EA-1060; Environmental Assessment Consolidation and Interim Storage of Special Nuclear Material at

environmental assessment (EA), DOE/EA - 1060, for the consolidation, processing, and interim storage of Category I and II special nuclear material (SNM) in Building 371 at the Rocky Flats Environmental Technology Site (hereinafter referred to as Rocky Flats or Site), Golden, Colorado. The scope of the EA included alternatives for interim storage including the no action alternative, the construction of a new facility for interim storage at Rocky Flats, and shipment to other DOE facilities for interim storage.

The DOE has identified a need to improve the environmentally and physically safe, secure, and verifiable storage of Category I and II SNM until long-term disposition is determined and implemented. This is a direct result of the changed mission to manage waste and materials, and to clean up and convert Rocky Flats for beneficial use. Additionally, DOE has determined that by consolidating Category I and II SNM in Building 371, considerable cost savings will be realized because of reduced surveillance and safeguard requirements. Long-term storage and disposition of SNM are under analysis in the Programmatic Environmental Impact Statement (PEIS) for Storage and Disposition of Weapons-Usable Fissile Materials (DOE, 1994). The duration of interim storage at Rocky Flats is projected to be 10 to 15 years.

The DOE is seeking to enhance the safety of SNM management at Rocky Flats. Containment of radioactive releases is one of the key objectives of ensuring safe operations and is heavily dependent upon the structural integrity of the buildings in which the SNM is located. Several of the buildings at Rocky Flats were designed and constructed before current nuclear design requirements were developed. Building 371 was built to stringent nuclear design standards and represents the most structurally sound building at the Site for storage of SNM.

In parallel with consolidation, DOE is studying ways to enhance the safety of storing SNM in Building 371. The studies are in response to the Defense Nuclear Facilities Safety Board Recommendation 94-3. A number of the safety improvements under consideration are consistent with the proposed action of the EA (e.g., one improvement under consideration is to over-pack the double-nested containers under the proposed action with a third container to prevent further dispersal of material from a catastrophic accident condition). Some of the improvements, however, exceed the scope of the EA. If DOE decides to pursue these improvements, further review will be required to evaluate all potential environmental effects.

A public meeting was held on April 18, 1995 to discuss the scope and analyses in the EA. The public and State of Colorado were given 30 days to comment on the EA. Eighty-eight written comments were received and subsequently were responded to in the final EA. Many of the comments expressed concerns about SNM consolidation in one building and about long-term storage of SNM at Rocky Flats. Others expressed concerns that additional alternatives should be considered. Complete documentation of these written comments and responses, as well as the proceedings of the public meeting held on April 18, 1995 are included in Appendix C of the EA.

PROPOSED ACTION: The proposed action consists of the consolidation, processing, and interim storage of Category I and II SNM (9.8 metric tons of plutonium and 6.7 metric tons of enriched uranium) in Building 371. The proposed action would involve the transfer of SNM from six buildings where it is currently stored to Building 371. Much of the SNM inventory is already located in Building 371. Activities that would be conducted when necessary to prepare the SNM prior to transfer to Building 371 include: reducing the size of metal pieces; packaging for transfer to Building 371; and transferring from current storage buildings to Building 371. Modifications in Building 371 to support the consolidation effort include: installation of SNM processing and packaging equipment; construction of a new vault; enhanced storage capacity in the central storage vault; and dock modifications to accept Safe, Secure Transports for offsite shipment of SNM.

Once the SNM is consolidated into Building 371, it would be processed for environmentally sound and physically safe storage. Activities performed in the proposed process line in Building 371 to prepare the SNM for safe storage include: removing plutonium oxide from the metal surface; reducing the size of metal pieces to accommodate the storage container; heating of the oxide to a range of 800^oC to 1200^oC in new furnaces within a glovebox to stabilize it; and placing the metal and oxide in an approved, inert-atmosphere, welded-seal storage container.

ALTERNATIVES CONSIDERED: DOE considered in detail the no action alternative which would continue the present practice of storing inventories of SNM in several existing buildings at Rocky Flats without regard to differences in structural integrity and resistance to release of airborne particulates under accident conditions. Current operating and management practices for SNM inventories require performance of inspections, processing of pyrophoric oxide into stable form, sampling, inventory/accountability, replacement of temporary packaging, and maintenance of facility safety systems. The no action alternative was considered unacceptable as it does not meet the DOE safety and risk reduction objectives for existing inventories of SNM.

Alternatives considered but eliminated from further analysis were construction of a new facility at Rocky Flats for interim storage and offsite shipment of SNM to other DOE facilities for interim storage. Neither of these alternatives were shown to meet the strategic or programmatic goals of reducing the risk and cost associated with interim storage of SNM until a permanent solution for storage within the DOE Weapons Complex becomes available.

ENVIRONMENTAL EFFECTS: Most activities associated with the proposed action and the no action alternative would take place inside existing buildings. As a result, neither of these alternatives would affect water or biological resources. An air quality assessment was conducted and no air quality impacts to the environment were anticipated. A small potential exits for acute worker exposure to radioactive materials from accidents. Chronic worker exposure to radiation would be limited to those levels accepted under federal regulation by adherence to standard practices under the "As Low As Reasonably Achievable" program. The cumulative effect of the proposed consolidation, processing to meet storage criteria, and interim storage in Building 371 at Rocky Flats would be to reduce the risks to both workers and the public over the long term. Other environmental effects would include a potential for a slight increase in annual emissions of radionuclides. However, these emissions would not be generated in quantities that would require a Colorado Department of Public Health and Environment Air Pollutant Emission Notice, new permit, or permit modification. The low-level and transuranic waste generated by consolidation activities would not result in any measurable environmental effects because of strict adherence to safety procedures and requirements for generating, storing, and shipping wastes at Rocky Flats.

FOR FURTHER INFORMATION ABOUT THIS ACTION, CONTACT:

Carl R. Sykes
Materials Management Division
U.S. Department of Energy
Rocky Flats Field Office
P.O. Box 928 - T124A
Golden, CO 80402-0928
Telephone: (303) 966-3684

PUBLIC AVAILABILITY:

Copies of this EA or further information on the DOE NEPA process are available from:

Patricia M. Powell
NEPA Compliance Officer
U.S. Department of Energy
Rocky Flats Field Office
P.O. Box 928 - 116
Golden, Colorado 80402-0928
Telephone: (303) 966-3260

DETERMINATION: Based on the information and analyses in the EA, DOE has determined that the proposed consolidation, processing, and interim storage of Category I and II SNM in Building 371 at the Rocky Flats Environmental Technology Site does not constitute a major Federal action significantly affecting the quality of the human environment within the meaning of the National Environmental Policy Act of 1969, as amended. Therefore, an Environmental Impact Statement for the proposed action is not required.

Signed in Golden, Colorado, this 22nd day of June, 1995.

Mark N. Silverman
Manager
Rocky Flats Field Office
U. S. Department of Energy

LIST OF ACRONYMS AND ABBREVIATIONS

ACL: Administrative Control Level
ALARA: As Low As Reasonably Achievable
APEN: Air Pollutant Emission Notice
CDPHE: Colorado Department of Public Health and Environment
CFR: Code of Federal Regulations
D & D: decontamination and decommissioning
^oC: degrees centigrade
DOE: U. S. Department of Energy
DOT: U. S. Department of Transportation
EA: environmental assessment
EDE: effective dose equivalent
EPA: Environmental Protection Agency
FONSI: Finding of No Significant Impact
FSAR: final safety analysis report
FY: fiscal year
g: gram
HEPA: high efficiency particulate air
IAEA: International Atomic Energy Agency
ICRP: International Commission on Radiological Protection
kg: kilogram
LANL: Los Alamos National Laboratory
LS/DW: Life Safety /Disaster Warning
mrem: millirem
NCRP: National Committee on Radiation Protection
NRC: Nuclear Regulatory Commission
NTS: Nevada Test Site
OSHA: Occupational Safety and Health Act
PACS: Personnel Access Control System
PEIS: programmatic environmental impact statement
PIDAS: Perimeter Intrusion Detection and Assessment System
PM^-10: particulate material less than 10 microns in size
RCRA: Resource Conservation and Recovery Act
rem: roentgen equivalent man (a unit of absorbed radiation dose in biological matter)
SAAM: selective alpha air monitor
SAR: Safety Analysis Report
SNM: Special Nuclear Material
SST: Safe, Secure Transport
TA: Technical Area
TSR: Technical Safety Requirements
TRU: transuranic
UPS: uninterruptible power supply
USCOE: U. S. Army Corps of Engineers
VSS: vital safety system
WIPP: Waste Isolation Pilot Plant

1.0 INTRODUCTION

The Department of Energy (DOE) is proposing the consolidation, processing, and interim storage of Category I and II special nuclear material (SNM) in Building 371 at the Rocky Flats Environmental Technology Site (hereinafter referred to as Rocky Flats or Site). Category I and II SNM is generally defined as quantities of nuclear material (plutonium and uranium) that pose an attractive theft or sabotage target, and thus require very stringent measures for secure management. Interim storage refers to the safe, controlled, verifiable storage facilities and conditions that would be established in the near term, approximately 10 to 15 years (DOE, 1994). The interim storage status would remain in effect until final disposition of the SNM is determined and implemented. This environmental assessment (EA) addresses the potential environmental effects resulting from the proposed action and the no action alternative.

Background Information

In 1989, all nuclear operations were halted at Rocky Flats. The SNM used in these operations was in various stages of production and located in several buildings when the work stopped. The material was placed in containers for temporary storage with the intent of resuming operations. However, in the State of the Union Address of January 1992, the President canceled production of the W88 warhead which was the primary mission at Rocky Flats. Subsequently, production activities at Rocky Flats were stopped, and the SNM used in those activities was stored in existing containers, awaiting further disposition. However, the available containers and facilities used during production were never intended for extended periods of storage. As a result of the change in mission to environmental restoration and cleanup, Rocky Flats must now place the SNM in suitable interim storage until final disposition is determined.

As part of the DOE's Openness Initiative, Secretary of Energy Hazel O'Leary announced in December 1993 that the total measured inventory of plutonium currently stored at Rocky Flats is 12.9 metric tons (approximately 28,400 pounds). In June 1994, Secretary O'Leary announced that the enriched uranium inventory at the Site is 6.7 metric tons (approximately 14,800 pounds). The scope of the SNM Consolidation and Interim Storage Program is limited to Category I and II SNM: 9.8 metric tons of plutonium in various forms and 6.7 metric tons of enriched uranium. The enriched uranium is anticipated to be shipped to the Y-12 facility in Oak Ridge, Tennessee. However, operations at the Y-12 facility are currently suspended. In the event that Y-12 does not resume operations, the enriched uranium would be consolidated in Building 371 and packaged for storage. The plutonium exists in various forms, including weapons parts, metal and alloy, and oxide used in support of the former Rocky Flats mission of nuclear weapons component production. The remaining 3.1 metric tons of SNM are residues, which are not Category I or II SNM, and therefore are not addressed in this EA.

Characterization of SNM

The SNM included in the program scope is grouped into three types: metal, oxide, and pits. Pieces of SNM that weigh 50 grams or more are identified as metal and are generally raw materials such as buttons, ingots, and completed or semi-fabricated parts. The SNM oxide includes pure plutonium oxide, plutonium oxide mixtures, and plutonium/enriched uranium mixtures and metal pieces that weigh less than 50 grams. These oxides are by-products of weapons fabrication and plutonium processing and sometimes contain other substances including fluorides, greases, and other impurities. Pits are a component part of nuclear weapons and will not require any processing before being transferred and stored in Building 371.

2.0 PURPOSE AND NEED

The DOE has identified a need to improve the environmentally and physically safe, secure, and verifiable storage of Category I and II SNM until long-term disposition is determined and implemented. This is a direct result of the changed mission to manage waste and materials, and clean up and convert Rocky Flats to beneficial use. Long-term storage and disposition of SNM are under analysis in the Programmatic Environmental Impact Statement (PEIS) for Storage and Disposition of Weapons-Usable Fissile Materials (DOE, 1994). The duration of interim storage at Rocky Flats is projected to be 10 to 15 years.

3.0 DESCRIPTION OF THE PROPOSED ACTION AND ALTERNATIVES

3.1 Proposed Action

The proposed action consists of the consolidation, processing, and interim storage of Category I and II SNM (9.8 metric tons of plutonium and 6.7 metric tons of enriched uranium) in Building 371 (Figure 3-1). The proposed action would involve the transfer of SNM from Buildings 707, 771, 776/777, 779, and 991 (refer to section 4.2) to Building 371 and much of the SNM inventory is already located in Building 371. Buildings 707, 771, 776/777, 779, and 991 will hereinafter be referred to as "export buildings."

The following activities would be conducted when necessary to prepare the SNM prior to transfer to Building 371:

reduce the size of metal pieces in Building 707
package for transfer to Building 371
transfer from export buildings to Building 371

The following minor modifications would be essential in Building 371 to support the consolidation effort:

installation of SNM processing and packaging equipment
construction of a new vault
enhanced storage capacity in the central storage vault
dock modifications to accept Safe, Secure Transports (SSTs) for offsite shipment of SNM

Figure 3-1 Proposed SNM Consolidation and Processing for Storage

Once the SNM is consolidated into Building 371, it would be processed for environmentally and physically safe storage. The following activities would be performed in the process line installed in Building 371 to prepare the SNM for safe storage:

remove as much of the oxide from the metal surface as possible by brushing
reduce the size of metal pieces to accommodate the storage container by breaking, cutting, sawing, pressing, etc.
heat the oxide to a range of 800íC to 1200íC in new furnaces within a glovebox to stabilize it and to remove any water content
place the metal and oxide in the approved, inert-atmosphere, storage container (refer to Section 3.1.5)

Thermal stabilization of plutonium oxides required for current fire safety purposes is addressed in the EA for Resumption of Thermal Stabilization of Plutonium Oxide in Building 707 (DOE, 1994a).

3.1.1 Selection of Building 371

Many factors were considered in the selection of Building 371 as the proposed location for consolidation and interim storage of Category I and II SNM. It is the only existing building at Rocky Flats that has the potential for meeting, without major modifications, the requirements for all aspects of SNM consolidation (EG&G, 1994). These requirements include health, environmental, and radiation safety protection, and the engineered capacity to withstand severe natural phenomena. The plutonium recovery area in Building 371 was designed to withstand a tornado with 300 mile-per-hour tangential winds; to maintain containment integrity through an earthquake with a 0.21 gravity surface acceleration (approximately 6.0 on the Richter scale); and to withstand forces greater than those anticipated from snowstorms and floods. The high efficiency particulate air (HEPA) filter-equipped exhaust stacks have isolation valves that close in less than 10 seconds to seal the building and protect it from both positive and negative pressures. The building was designed for fire prevention and has comprehensive fire detection and suppression systems. The building utilizes the safe-refuge concept of directed air flow and physical barriers to isolate areas of greater hazard, augmented by a short travel distance from a hazardous zone to a safer zone. These air flow and containment zones provide environmental integrity which is assured by a comprehensive monitoring program.

Building 371 is proposed for consolidation and interim storage of Category I and II SNM for other reasons as well. It is the only building with the capacity to store the entire Rocky Flats Category I and II SNM inventory, and it is already the single largest repository of SNM at the Site. This means that there would be less work involved in bringing the remainder of the SNM to Building 371 than there would be in taking its inventory to another onsite location.

3.1.2 SNM Preparation and Other Activities Performed in Export Buildings

SNM Preparation

Consolidation of SNM would be preceded by other actions required to prepare the SNM for safe transfer and storage. The 700 Area SNM Preparation Program is addressed in the EA for Resumption of Thermal Stabilization of Plutonium Oxide in Building 707 (DOE, 1994a). This program includes the removal of plastics from the inner storage containers and the oxide to be brushed from metal part surfaces. The brushed metal pieces are packaged and placed temporarily in secured storage areas. The oxide collected from brushing the metal, as well as other unstabilized oxide in the 700 area, is thermally stabilized, packaged, and placed temporarily in secured storage areas. Stabilized oxide from the Solution Stabilization Program, as proposed in the EA for Actinide Solution Processing at Rocky Flats Environmental Technology Site (DOE, 1995), would be consolidated into Building 371.

Metal pieces not already located in Building 371 that are too large to fit into SNM containers would be cut into smaller pieces in Building 707. They would then be packaged in 1-liter containers and returned to temporary secured storage. The metal pieces would be transferred between Building 707 and Buildings 771, 776/777, and 779 through connecting tunnels and enclosed passageways (Figure 3-2) on transfer carts designed specifically for moving SNM.

Figure 3-2. Proposed Onsite Movement for SNM Consolidation.

SNM Packaging and Transfer by Truck

Packaging of SNM for transfer to Building 371 would be performed in Buildings 707, 771, 776/777, and 779. All of the SNM being transferred to Building 371 would be packaged in transfer containers. The SNM would be transferred by truck from Buildings 707, 771, 776/777, and 991 to Building 371 (Figure 3-2). The SNM would be transported by the most direct route practicable which would be free of any construction or other hazards. The truck route would be closed to other Site traffic during the transfer.

3.1.3 Construction of a Storage Vault in Building 371

As part of the proposed action, Room 3337 in Building 371 would be modified to become a storage vault for SNM. This modification, along with the stacker/retriever maintenance and upgrade activities, would create secure capacity within Building 371 to support the requirements of the SNM Consolidation and Interim Storage Program.

Room 3337 originally contained tanks supporting plutonium processing operations. In the mid-1980s it was decommissioned and all of the interior tanks and piping were removed. The room currently contains no process or process-related equipment. It is now used as storage for 55-gallon drums containing residues and transuranic (TRU) waste. Under the proposed action, the residues and TRU waste would be relocated to another existing storage location, either within Building 371 or in another building at Rocky Flats. The relocation would comply with all regulatory requirements.

The room is constructed of 2-foot-thick, reinforced concrete walls. Essential modifications to the room would include the following:

installation of two steel mezzanines, for a total of three storage levels (including the ground level)
installation of individual bins for SNM storage with features for criticality prevention and radiological shielding
installation or modification of safety systems such as selective alpha air monitors (SAAMs), criticality detectors, and heat detectors
security fixture upgrades and remote monitoring equipment

3.1.4 The Central Storage Vault and Stacker/Retriever in Building 371

The central storage vault, Room 1206 in Building 371, is the single largest SNM repository at Rocky Flats. It features reinforced concrete walls, remote handling equipment (the stacker/retriever), and a nitrogen (inert) atmosphere. The stacker/retriever is a computer operated shuttle for moving SNM between the central storage vault and the input/output stations. The central storage vault is a compartment approximately 300 feet long, 15 feet wide, and 40 feet high. A total of 1,428 storage bins in steel tiers are mounted against the walls on either side of the compartment. There are currently 150 empty storage bins. Material pallets would be procured and placed into the central storage vault to increase storage capacity of SNM.

Currently, SNM is transferred on aluminum pallets about four feet square that hold four permanently attached, double-walled, lead-shielded receptacles. The proposed SNM containers (refer to Section 3.1.5) would be placed into the shielded receptacles. The stacker/retriever also handles approximately 100 flatbed pallets which have a lip around their edges to prevent materials from falling off. These pallets could be easily modified to become material pallets to further increase the SNM storage capacity of the central storage vault.

The building cannot receive new material pallets into the central storage vault. Input/Output Station No. 6 would have to be modified in order to receive the pallets. This modification would require cutting a hole in the input/output station large enough to move the pallets through it. A glovebox would be attached to this penetration and would incorporate lifting and handling equipment for moving the pallets. The glovebox would prevent the release of contamination and maintain the inert atmosphere within the central storage vault.

The stacker/retriever is a large and complex system which requires regular and frequent maintenance. Maintenance work would be performed in order to ensure the continued operability of the system. This would include activities such as lubrication, repair, and replacement of various stacker/retriever components.

3.1.5 SNM Processing in Building 371

In order to prepare SNM for safe storage, the requirements of the DOE Criteria for Safe Storage of Plutonium Metal and Oxide (DOE, 1994b) would be implemented. The requirements are as follows: 1) oxide is in a stabilized form; 2) both metal and oxide are free of plastics and stored in sealed, corrosion-resistant containers in an inert atmosphere that does not create a need for further processing; and 3) a minimum of two radiation barriers are present.

A process line would be installed in Room 3206 of Building 371 (Figures 3-3 and 3-4) to implement these criteria. The process line would interface with the stacker/retriever through Input/Output Station No. 6. Three new furnaces would be installed in the process line that would have the capability to thermally stabilize oxide within a range of 800^oC to 1200^oC. Thermal stabilization within this range would meet the DOE test criteria (Loss-On-Ignition) for removing moisture, completing the oxidation reaction, and eliminating any remaining potentially corrosive compounds. In addition, the dispersibility hazard would be reduced by increasing the oxide particle size. Enriched uranium oxide would not require thermal stabilization because of its chemical stability. The Loss-On-Ignition testing would be performed within the process line. Even oxides that were previously stabilized to render them nonpyrophoric would be subject to this stabilization process.

Within the process line, all plastics would be removed, metal pieces would be brushed to remove any oxide, and metal pieces too large to fit the into the storage container would be reduced in size. The SNM content of each container would be as close as possible to, but not greater than 4.5 kg per container of metal; and as close as possible to, but not greater than 5.1 kg per container of oxide. Other equipment used to support the process line (e.g., heating, ventilation, and air conditioning equipment) may be installed on the second floor of the building.

Figure 3-3. Layout of Proposed Process Line in Building 371 (Room 3206).

Figure 3-4. Proposed Process Flow of SNM in Building 371.

Figure 3-5. Proposed Storage Containers

Los Alamos National Laboratory (LANL) is developing corrosion-resistant, nested, welded storage containers (Figure 3-5). The requirement for a minimum of two radiation barriers would be met as follows:

The nested (inner material container and outer boundary container) combination would be used for storage in vaults and vault-type rooms with normal air atmospheres.
The material container alone would be used in the central storage vault because the shielded material pallets would serve as the second radiation barrier.

To meet the requirement that the SNM be stored in an inert atmosphere that would not create a need for further processing, both metal and oxide would be placed in material containers which would be filled with helium and then welded shut. The helium would serve as a means for leak checking the welded containers. The material containers to be stored in the shielded material pallets in the central storage vault would pass through the process line to Input/Output Station No. 6 and then into the central storage vault via the stacker/retriever.

As shown in Figure 3-4, the material containers to be stored in other vaults or vault-type rooms in Building 371 would undergo the following steps: 1) decontamination; 2) removal from the contaminated glovebox; 3) placement in a helium-filled, noncontaminanted glovebox; 4) placement inside the boundary container; and 5) welded shut. The nested containers would be leak checked, removed from the process line, and moved to a secured storage area.

The existing glovebox line in Room 3206 would be utilized as practical and replaced where necessary (Figure 3-3). Laboratory and measurement equipment from other Rocky Flats buildings would be installed as needed and used in the process line. The process line would incorporate redundant systems for safety purposes so that downtime for individual systems within the process would not halt the entire operation. The capacity of the process line would average 11 kg/day. At this rate, the entire inventory of Category I and II SNM could be processed by fiscal year 2002.

3.1.6 Measurement Equipment and Analytical Capabilities

In order to support the interim storage mission, the capability to analyze and characterize nuclear materials must be available in Building 371. This capability would support both the process line and nuclear material accountability requirements. Essential equipment likely would include package (drum or can) scanners, calorimeters, neutron detectors, gamma scanners, and other measurement equipment. Areas within Building 371 would be modified as necessary (e.g., equipment removals, drum relocation, power drops, etc.).

3.1.7 Refurbishment of Shipping Dock and Modifications to Accommodate SSTs

Shipping dock 18T in Building 371 would be modified to be compatible with SSTs used for offsite shipment of SNM. Modifications to the shipping dock would be fairly limited. A dock leveler would be installed; an enclosure would be built outside the dock to accommodate the dimensions of the SSTs; and various electrical, fire protection, and other safeguards and security upgrades would be undertaken as appropriate.

3.1.8 Waste Management

Low-level and transuranic (TRU) waste would be generated during the course of the proposed action activities. The waste would be assayed to determine how to categorize it. Low-level waste contains 100 nanocuries per gram or less of TRU elements and TRU waste exceeds this concentration.

Under the proposed action, approximately 130 cubic yards (approximately 9 fifty-five-gallon drums and 30 crates) of low-level waste and approximately 1,040 cubic yards (approximately 3,800 fifty-five-gallon drums) of TRU waste would be generated. There is no regulatory limit on the quantity of low-level or TRU waste that can be stored onsite; however, the low-level waste would be sent to an approved disposal facility. It is anticipated that there is adequate storage capacity at Rocky Flats for the low-level and TRU waste generated from the proposed action activities.

Approximately 100 cubic yards (374 fifty-five-gallon drums) of TRU waste currently is located in Room 3337 of Building 371. This room would be modified to become a storage vault for SNM under the proposed action, and the TRU waste would be moved to another approved storage location, either within Building 371 or in another storage location at Rocky Flats.

3.2 No Action Alternative

The no action alternative would continue the present practice of storing inventories of SNM in available nuclear materials buildings at Rocky Flats without regard to differences in structural integrity and resistance to release of airborne particulates under accident conditions. Under the no action alternative, material storage would continue in Buildings 371, 707, 771, 776/777, 779, and 991. Current operating and management practices for SNM inventories require performance of inspections, processing of pyrophoric oxide into stable form, sampling, inventory/accountability, replacement of temporary packaging, and maintenance of facility safety systems. The present practice requires that these activities be conducted in all facilities at Rocky Flats which store, process, and maintain SNM. Under the no action alternative, SNM storage and management activities would continue to be performed in many buildings throughout the Site. SNM would be managed in a total of 22 storage vaults as compared to 7 vaults (and vault-type rooms) which would be utilized under the proposed action in Building 371. This point is important because six workers are required in order to access one vault. The following activities would be conducted under the no action alternative:

frequent surveillance of material in 22 vaults
inventory of the material occurs bimonthly
selective alpha air monitors (SAAMs) and criticality monitors must be inspected and maintained on a potential daily basis
alarm testing must occur monthly and annually

The Rocky Flats Health and Safety Practices (EG&G, 1994) requirements would continue until final disposition of SNM is determined and implemented . These requirements include biannual inspection, weighing, and stabilization of the material. The biannual inspection may result in the following activities: 1) unpacking the current storage container, 2) brushing the metal, 3) repackaging the metal, 4) transferring unstabilized oxide to Building 707, 5) thermally stabilizing the oxide, and 6) repackaging the stabilized oxide.

Any future offsite transfer of SNM to a long-term storage facility would be severely impeded because the material would not be packaged in appropriate storage containers, and would be stored in many locations rather than in the proposed centralized storage area equipped with a transfer-ready shipping dock. In addition, the SNM would still require preparation and handling to ready it for final disposition.

3.3 Alternatives Considered But Not Further Analyzed

Alternatives to the proposed action and the no action alternative are described in the following sections. None of these alternatives have been shown to meet the strategic or programmatic goals of reducing the risk and cost associated with interim storage of SNM until a permanent solution for storage within the DOE Weapons Complex becomes available. The alternatives for interim storage other than the no action alternative include construction of a new facility for interim storage at Rocky Flats and shipment of SNM to other DOE facilities for interim storage.

3.3.1 Construction of a New Consolidation and Interim Storage Facility at Rocky Flats

This alternative would provide the capability to store SNM inventories safely after the facility is completed and qualified for use. The new storage facility would be located within the existing Protected Area in order to preserve current security and safety measures. This alternative may also require the demolition of existing building(s) before construction could begin. Siting of the facility outside of the existing Protected Area's Perimeter Intrusion Detection and Assessment System (PIDAS) security enclosure would result in a requirement for a new security enclosure with fences and sophisticated surveillance systems. Due to funding, design, permitting, and building requirements, the time required to complete consolidation of the SNM into the facility would be approximately 10 to 16 years.

This alternative would not meet the risk reduction objectives of consolidation and interim storage for several reasons. A new facility would have design and structural integrity characteristics similar to those already available with Building 371. Any reduction in risk to workers or the public would be delayed. The new facility would still be in the Denver metropolitan area and would not decrease safety or health risks by increasing distance from this population center.

The construction and operation of a new SNM storage facility potentially would result in environmental impacts that would not occur if consolidation and interim storage proceeds in the existing Building 371 facility. Construction of the facility in the Industrial Area would likely create a soil disturbance resulting in a potential for airborne radiological contamination. The new facility also would be very costly and would offer no additional risk reduction or improvement in environmental protection as compared to Building 371.

3.3.2 Shipment of SNM to Other DOE Facilities for Interim Storage

The alternative to ship SNM to other DOE facilities for interim storage would achieve long-term risk reduction to the public, but is not feasible over the next 10 to 15 years. There are currently several facilities around the DOE Weapons Complex which store and process relatively small quantities of SNM, but they have little or no excess capacity for SNM storage. In contrast, Rocky Flats is one of very few facilities with the capability to store large quantities of SNM.

No single offsite facility or combination of sites meets all of the requirements for storing the Rocky Flats SNM inventory. The DOE Weapons Complex facilities investigated for this purpose include Savannah River Site, Los Alamos National Laboratory, Pantex Plant, and the Hanford Site.

The Savannah River Site, located near Aiken, South Carolina, has five vaults with the capacity to store plutonium. However, these vaults cannot handle the powders, chunks, metal solids, and other compound forms of SNM currently stored at Rocky Flats. Two other vaults are currently being used to store SNM at Savannah River Site and do not have the capacity to store additional SNM from Rocky Flats.

Los Alamos National Laboratory (LANL) is located in Los Alamos, New Mexico. Pits and other forms of plutonium not sealed up in weapons have been stored in the Technical Area 41 (TA-41) and TA-55 facilities. The TA-55 facility is at approximately 90 percent capacity and over-committed for LANL pit storage needs. No additional capacity for inventories of SNM from Rocky Flats exists. The TA-41 facility is inactive because it does not meet current DOE requirements for environment, safety and health, security, and conduct of operations. The programmatic requirements at LANL did not justify the costs associated with the required changes at the TA-41 facility.

The Pantex Plant is located near Amarillo, Texas. Although Pantex is planning to increase its interim storage capacity for plutonium pits from its current inventory of 6,800 to 20,000, there are no plans to construct vaults for storing other forms of SNM. The type of steel magazine used for pit storage at Pantex is unsuitable for the safe and secure storage of other forms of SNM.

The Hanford Site is located in south-central Washington State, near the city of Richland. The primary mission at the site is environmental restoration. Hanford is not a candidate for additional storage due to prohibitive costs associated with the conversion of facilities, the termination of the site defense mission, and the commitment to clean up the site (DOE, 1994). As such, Hanford currently is not a viable choice for interim storage of inventories of SNM from Rocky Flats.

None of the individual DOE Weapons Complex sites meet all of the engineering criteria for consolidation and interim storage of the entire Rocky Flats SNM inventory. Although some quantities of the Rocky Flats inventory could be shipped to these sites, processing and packaging would still be required to ship even small quantities of SNM. The material shipped to offsite destinations would be shipped a second time once the long-term storage site is selected. This double shipping would result in increased risks to the environment and to public and worker health. Increased security risks would also result from the additional handling and transportation activities.

A long-term storage solution is being analyzed in the PEIS for Storage and Disposition of Weapons-Usable Fissile Materials (DOE, 1994); however, this solution will not be available for at least ten years. Due to this delay in the long-term storage decision and the other reasons discussed above, immediate shipment of SNM inventories from Rocky Flats is considered to be infeasible.

4.0 AFFECTED ENVIRONMENT

4.1 Natural Environment

Rocky Flats is located on 6,550 acres in rural northern Jefferson County, Colorado, 16 miles northwest of downtown Denver (Figure 4-1). The Rocky Flats Industrial Area occupies approximately 400 acres in the middle of the Site. The remaining 6,150 acres form a Buffer Zone around the active part of Rocky Flats. The Buffer Zone provides a distance of more than one mile between the developed portion of the Site and any public road or private property.

Rocky Flats is 6 miles from the nearest school and 10 miles from the nearest hospital. Approximately 291,000 people live within 10 miles of the Site, over 1,100,000 within 20 miles; while the entire metropolitan Denver area, with a population of over 2.1 million, is within 50 miles of the Site (EG&G,1994a). Population centers are generally to the northeast and southeast of the Site.

Rocky Flats is located on a broad alluvial terrace at the base of the Rocky Mountains at an elevation of about 6,000 feet. Underlying the Site is the Rocky Flats Alluvium, a soil composed of cobbles, coarse gravel, and sand over a largely claystone bedrock. Seismic activity in the area is low and the potential for landslides and subsidence is minimal. Adjacent land uses are agricultural to the west, agricultural with some industrial to the south, agricultural and very-low-density residential to the east, and agricultural/open space to the north.

The climate at Rocky Flats is mild, sunny, and semi-arid with an average of 15 inches of precipitation annually. Winds are generally out of the west and northwest with an average velocity of 8 to 9 miles per hour. Wind gusts exceeding 60 miles per hour occur frequently throughout the year, and gusts exceeding 100 miles per hour occur occasionally. Peak gusts are associated with the winter months.

Figure 4-1. Location of Rocky Flats Environmental Technology Site.

The air quality is generally better at Rocky Flats than in the urbanized portion of the Denver metropolitan area. However, the greater Denver area, including Rocky Flats, is a non-attainment area for carbon monoxide and PM-10 (particulate material less than 10 microns in size), and is in interim compliance for ozone (EPA, 1994). Air emissions from Rocky Flats are within permitted limits for all pollutants for which there are standards. Radionuclide emissions from Rocky Flats are limited by Clean Air Act regulations (40 CFR Part 61, Subpart H) to those amounts that would result in the public receiving a dose of 10 millirem (mrem) per year. The dose of radionuclide emission (point-specific and diffuse sources) to the public from Rocky Flats in 1993 was 0.0016 mrem (EG&G, 1994b). In comparison, the annual natural background radiation for the Denver area is approximately 350 mrem (NCRP, 1987).

Surface water drainage from Rocky Flats flows to the east. The developed area of the Site is drained by Woman and Walnut Creeks, while three other streams drain portions of the Buffer Zone. Ponds on Woman and Walnut Creeks store stormwater runoff from the Site and from the Rocky Flats sewage treatment plant. The contents of the ponds are analyzed to ensure they meet the standards of the Colorado Water Quality Control Commission prior to release downstream. Rocky Flats is not located within the 100-year floodplain as classified by the U.S. Army Corps of Engineers (USCOE, 1992).

Scattered wetlands exist throughout the Site including three small wetlands (combined area less than one acre) between Buildings 371 and 776/777 (ASI, 1990). None of these wetlands are located in the immediate area of the proposed action (Krause, 1994).

The Buffer Zone provides habitat potentially suitable for the Ute Ladies'-Tresses, an orchid listed by the U.S. Fish and Wildlife Service as "threatened." However, individuals of the species were not found in the first or second of three consecutive annual Site wide surveys (ESCO, 1993). A small community of a Colorado plant "species of concern," the forktip threeawn, has been identified along the railroad tracks that enter Rocky Flats from the west along the west access road. This area is over a mile from the location of the proposed action activities. No habitat suitable for either of these species has been documented within the area of the proposed action.

Habitat suitable for a federal Category 2 plant species (a species whose listing as "threatened" or "endangered" may be appropriate, but for which adequate data are not available), the Colorado Butterfly Weed, exists in the Buffer Zone, but no individual of the species has been found in recent surveys (ESCO, 1993). The Preble's Meadow Jumping Mouse is a Colorado "species of concern" and a federal Category 2 species which DOE treats as an endangered species. It is a resident of many of the riparian areas at Rocky Flats, including those along Woman Creek. No threatened or endangered species, other species of concern, or migratory birds were found in a survey conducted in September 1994 in the undeveloped area east and north of Building 371 (Ryon, 1994).

4.2 Built Environment

The Rocky Flats built environment is the Industrial Area in which the majority of work activities occur and where most of the Site's workers are located. The locations of buildings at Rocky Flats are shown in Figure 4-2 (the buildings that play a role in the proposed Category I and II SNM Consolidation and Interim Storage Program are highlighted.) Buildings 371 and 707 would play the most active role in the proposed action while Buildings 771, 776/777, 779, and 991 would perform consolidation support functions.

The remainder of this section provides a description of these buildings. With the exception of Building 371, all of the buildings were built to commercial industrial standards. Building 371 was built to strict nuclear design standards.

4.2.1 Building 371

Building 371 was originally built to: 1) recover plutonium from residues generated by plutonium-related fabrication, assembly, and research activities throughout Rocky Flats; 2) convert the recovered plutonium into high-purity buttons; and 3) recover associated americium and convert it into americium dioxide, a saleable product. The building, completed in 1981, was built to stringent nuclear design standards and was intended to replace facilities in Building 771.

Building 371 currently stores Category I and II SNM and is proposed to be the primary SNM consolidation and interim storage facility until final disposition is determined and implemented. Portions of the Rocky Flats plutonium residues, TRU waste, and RCRA waste inventories currently are stored in Building 371. The exterior walls of the building, both above and below grade, are cast-in-place reinforced concrete. The walls can withstand the forces imposed by a tornado or a design-basis earthquake of approximately Richter 6.0 and still provide an outer containment barrier for radioactive materials. Vaults have reinforced concrete walls that are 8 inches to 24 inches thick. Stairway and elevator walls are constructed of poured-in-place concrete. Walls divide process areas into compartments separated by wide access corridors. Additional walls within the compartments form tank vaults, process canyons, and control rooms. Canyon and tank vault walls are constructed of 2-foot-thick concrete to protect workers from any possible radiation emissions. Dispersal of airborne radioactivity within the building is minimized by "cascading" differential pressures from areas of low potential contamination to areas of high contamination. The differential pressure within each ventilation zone is maintained by redundant fans. The building has both normal and emergency power supplies and contains various types of fire detection/alarm and fire suppression systems. Other detection and alarm systems provide airborne radiation monitoring and criticality detection for the building.

The four-level facility has approximately 186,000 square feet of floor space and contains six plutonium storage vaults and vault-type rooms. The stacker/retriever moves radioactive materials between the central storage vault and the input/output stations. In addition to this transport capability, the central storage vault was designed for storage of Category I and II SNM.

Figure 4-2. Buildings 371, 707, 771, 776/777, 779, and 991 at Rocky Flats Environment Technology Site.

4.2.2 Building 707

Building 707 was built as a manufacturing facility for casting, fabricating, assembling, and testing finished plutonium parts. Operations in the facility were divided into six categories:

1) metallurgy, 2) fabrication (machining), 3) assembly, 4) inspection, 5) nondestructive testing, and 6) support. The building was completed in 1969 and is the primary facility for metal brushing, size reduction of metal, and thermal stabilization activities.

Building 707 is a two-story facility with 74,240 square feet per floor. A single-story portion with 18,560 square feet comprises the east side of the building. The building contains ten modules in which various manufacturing activities have taken place in the past. Building 707 is connected directly, through other buildings or by tunnels, to Buildings 776/777, 771, 778, and 779.

4.2.3 Building 771

Building 771 was built in 1953, primarily for use in plutonium recovery, but it also has capabilities for chemical research, plutonium metallurgy, and analytical laboratory activities. The building once housed maintenance shops and a waste packaging facility. Three basic operations were conducted in the building: 1) chemical and physical processes for recovering and refining plutonium metal and americium oxide; 2) plutonium chemistry research; and 3) radiological analyses of samples for isotopic content, impurities, and trace elements. The principal operation was recovery of plutonium from residues generated during plutonium-related fabrication, assembly, and research operations throughout the Site.

Building 771 is a two-level facility with approximately 151,000 square feet of floor space and stores plutonium that requires stabilization. The building is connected by a tunnel to Building 776/777 which is directly connected to Buildings 779 and 707. The tunnel between Buildings 771 and 776 is concrete-lined and is equipped with a HEPA filtration ventilation system.

Calorimetry, a material balance process used to determine the quantity of plutonium in a storage container, is performed in Building 771 for the pyrophoric oxide that is stabilized in Building 707. Calorimetry has continued in Building 771 during curtailment of nuclear operations as part of ongoing plutonium management operations.

4.2.4 Building 776/777

Building 776/777 is comprised of two adjoining buildings and is considered as a single structure. Building 776/777 was originally built for six major categories of operations: 1) weapons production support; 2) site-return processing; 3) waste operations; 4) research and development; 5) special projects; and 6) support activities such as radiation monitoring, maintenance, and process materials support. Currently, Building 776/777 is used for waste operations such as drum storage and residue drum venting.

Building 776/777 is a two-story facility with approximately 156,200 square feet of floor space and contains SNM that requires stabilization. The building is connected to Building 779 by an enclosed hallway, to Building 771 by a tunnel, and to Building 707 via Building 778.

4.2.5 Building 779

Building 779 is a research and development facility originally built to support production and recovery processes. The facility was completed in 1965 and the external structure was subsequently upgraded to withstand an earthquake of 6.0 on the Richter scale.

Although production activities have been halted, research and nonnuclear production support activities such as liquid carbon dioxide cleaning, waste minimization/characterization, stockpile reliability evaluation, and surface analyses continue. The building consists of approximately 68,000 square feet of floor space on two floors with a small basement and contains SNM that requires stabilization. The building is connected by tunnel either directly, or through other buildings to Buildings 776/777, 707, and 771.

4.2.6 Building 991

Building 991 was built in 1952 and is used primarily for shipping SNM and other certified product materials (including nonnuclear materials). The facility and its associated underground tunnels and vaults are also used for storing SNM and other certified product materials.

Operations in the building are the standard warehousing functions of receiving, storing, and shipping these materials, both onsite and offsite. In the past, there were several operations involving nondestructive testing, machining, inspection, and final quality acceptance certification of nuclear and nonnuclear materials. Current operations in the building consist of nondestructive testing, a metrology laboratory, a surface laboratory, an alarms maintenance shop, various logistics activities, and storage of waste.

4.3 Safety Systems

Throughout the SNM Consolidation and Interim Storage Program, safety systems would be in place to protect workers, the public, and the environment. The systems include vital safety systems (VSSs) and design features such as gloveboxes, vaults, and other building systems.

Worker safety is further enhanced by personal protective equipment and other requirements in accordance with the Occupational Safety and Health Act (OSHA) and other applicable regulations. Administrative safety procedures also enhance the safe conduct of operations.

The VSSs prevent and mitigate potential accidents. These systems have surveillance testing requirements and limits for operations which are specified in the Operational Safety Requirements for the Building 371 Final Safety Analysis Report (FSAR) and in FSARs for the export buildings. Table 4-1 lists the VSSs in Building 371 and many of the export buildings that are designed to help ensure safe operation of the SNM consolidation and processing activities. Brief descriptions of these systems are provided below; more detailed descriptions can be found in each building's FSAR.

The SNM processing activities would be performed in gloveboxes. Gloveboxes are totally enclosed structures made of steel and leaded glass and are accessible through gloveports. Workers handle SNM through the gloveports so that there is no direct physical contact with the SNM. Gloveboxes used in association with SNM processing are equipped with an exhaust HEPA filter to prevent accumulation of SNM in exhaust ductwork.

Personal protective equipment is provided to enhance worker safety. Throughout the proposed action activities, operators would be equipped with appropriate protective clothing as determined by job reviews and documented on radiation work permits. Each operator is trained on the safety equipment required for each activity. Each person involved in an activity is required to read and follow the requirements of the radiation work permit. The normal equipment required for operations involving SNM is coveralls, external radiation dosimeters, safety glasses, and safety shoes. Many of the operations also require using two pairs of surgical gloves. Workers use alpha monitors to check for SNM contamination each time they exit a set of glovebox gloves. If contamination is found, work stops until the cause is identified and corrected.

Table 4-1. Vital Safety Systems in Building 371 and Export Buildings.

Vital Safety System	Description
Ventilation Systems	Maintains negative pressure in gloveboxes
	Filters all exhaust through stages of HEPA filters
	Provides some gloveboxes with inert atmospheres
Selective Alpha Air Monitors (SAAMs)	Monitors the modules and effluent exhaust for airborne contamination
Fire Protection Systems	Detects and suppresses fires in gloveboxes, plenums, and modules in Building 371 and the export buildings
Life Safety/Disaster Warning System	Transmits audio alarms and safety announcements through public address speakers
Criticality Alarm System	Detects and transmits alarms of any criticality
Emergency Power System	Emergency diesel generators back up normal and alternate utility electrical power supplies
	Uninterruptible power for sensitive electrical loads engage upon loss of normal and alternate power

Ventilation

Many of the SNM preparation activities described in Section 3.0 would be conducted within the confines of gloveboxes. Ventilation systems maintain the gloveboxes at a negative pressure. If any breach were to develop (e.g., a torn glove), the flow of air would be from the room to the gloveboxes, thus limiting the spread of contamination.

Exhaust air from gloveboxes must pass through four stages of HEPA filters prior to release to the atmosphere. Each stage of HEPA filters provides a removal efficiency of at least 99.8 percent. The multi-stage HEPA filters essentially prevent contamination from reaching the atmosphere. Only one stage of the HEPA filters is tested to verify efficiency in Buildings 771, 776/777, and 779; two stages are tested in Buildings 371 and 707.

Selective Alpha Air Monitors

Selective Alpha Air Monitors (SAAMs) monitor and detect the presence of airborne contamination in rooms, plenums, and modules. Upon the alarm of a SAAM, remedial actions are taken to prevent worker exposure and release of contamination to the environment.

Fire Protection

Fire protection VSSs provide fire detection and fire suppression in all buildings containing radioactive material. Gloveboxes and exhaust plenums are equipped with glovebox overheat detectors which sound an alarm should ambient temperature in the system rise. Alarm indication is provided both locally and to the fire department. Fire detection systems sound an alarm should a fault occur within the system.

Exhaust plenums are protected by a water deluge system that sprays water before the first stage of HEPA filters in the event of an overheated plenum. The water deluge system protects the integrity of the HEPA filters. Further fire suppression capability is provided by fire hoses and fire extinguishers.

Life Safety/Disaster Warning

The Life Safety/Disaster Warning (LS/DW) VSS provides a means for the audio transmission of alarms and safety announcements over public address speakers located in all buildings.

Criticality Alarm

The criticality alarm VSS detects any criticality event through the use of numerous detectors. The system provides audio and visual beacon alarms. A criticality event is extremely unlikely due to the small amounts of SNM being handled at any one time and the size and configuration of containers used for transportation and storage. Strict administrative controls called criticality safety limits are enforced in all buildings to control the amounts and forms of SNM in any given location.

Emergency Power

Normal and alternate power is supplied from the Public Service Company of Colorado to the VSSs. Emergency diesel generators provide backup power capabilities should normal and alternate power be lost. Uninterruptible power supply (UPS) systems would provide continuous power for sensitive components of VSS electrical loads upon loss of power. For example, fire detection panels, the LS/DW system, and the criticality alarm system all have their own backup batteries or UPS system.

5.0 ENVIRONMENTAL EFFECTS

It is DOE policy to conduct operations in compliance with all applicable federal, state, and local laws and regulations, and with all applicable DOE Orders. Environmental monitoring programs are implemented to identify and minimize environmental impacts from Site operations. The air, groundwater, and surface water in and around the Site are monitored routinely. Air emissions are monitored at all potential sources and at ambient air monitors located around the Site boundary and other offsite locations. Rocky Flats has comprehensive groundwater and surface water programs for monitoring and characterizing the water quality and flow patterns in the Site area. The annual Site Environmental Report for Rocky Flats (EG&G, 1994a) presents summary environmental data and a discussion of environmental monitoring and compliance programs at the Site. The report also includes an estimate of the impact of Site operations on human health and the environment.

The expectation is that neither the proposed action nor the no action alternative would cause any adverse environmental effect. Therefore, this EA focuses on the human health effects potentially resulting from radiological exposures associated with the proposed action and the no action alternative. The other alternatives described in Section 3.3 of this EA were determined to be infeasible and were not analyzed further.

A radiological risk comparison is depicted at different stages of the proposed action and the no action alternative for risk to the public (Figure 5-1) and risk to workers (Figure 5-2). The time period for these comparisons extends from the start of consolidation activities through the end of interim storage (approximately 10 to 15 years). The arbitrary risk dimension illustrates how risk increases or decreases with time (refer to Appendix A for information on risk assessment).

The risk analyses in this section use the conservative assumption that risk to the public is equal to that of the maximally exposed offsite individual (i.e., a hypothetical person who lives continuously at a point on the Site boundary where exposure to the public from accidents would be the highest).

Figure 5-1. Radiological Risk to the Public from the Proposed Action and the No Action Alternative

Figure 5-2. Radiological Risk to Workers from the Proposed Action and the No Action Alternative.

5.1 Non-Radiological Environmental Effects

Most activities of both the proposed action and the no action alternative would take place inside existing buildings. As a result, neither of the alternatives would affect water or biological resources. A wetlands analysis was conducted and concluded that the small areas of wetlands within the Protected Area would not be impacted adversely (Krause, 1994). A review of the Site hydrologic analysis concluded that no floodplains would be affected (USCOE, 1992). An air quality assessment was conducted and no air quality impacts to the environment were anticipated (Putney, 1994).

5.2 Waste Management Environmental Effects

Proposed Action

Under the proposed action, approximately 130 cubic yards (approximately 9 fifty-five-gallon drums and 30 crates) of low-level waste and approximately 1,040 cubic yards (approximately 3,800 fifty-five-gallon drums) of TRU waste would be generated. There is no regulatory limit on the quantity of low-level or TRU waste that can be stored onsite; however, the low-level waste would be sent to an approved disposal facility. It is anticipated that there will be adequate storage capacity at Rocky Flats for the low-level and TRU waste generated from the proposed action activities.

The generation, relocation, and storage of this waste would not result in any measurable environmental effects because of strict adherence to safety procedures and requirements for managing waste at Rocky Flats.

No Action Alternative

Approximately 510 cubic yards (approximately 1,860 fifty-five-gallon drums) of TRU waste would be generated under the no action alternative by ongoing thermal stabilization and other SNM maintenance activities over the interim storage period. It is anticipated that there will be adequate storage capacity at Rocky Flats for the TRU waste generated from the no action alternative. The generation of this waste would not result in any measurable environmental effects because of strict adherence to safety procedures and requirements for managing waste at Rocky Flats.

5.3 Radiological Environmental Effects

Risk resulting from the proposed action or the no action alternative has two components: risk from normal operations and risk from accidents. For each component, risk results from exposure to ionizing radiation. The source of ionizing radiation at Rocky Flats is SNM. The amount of radiation a person may experience is called the radiation dose. An internal dose results from the SNM entering a person's body. An external dose results from a person being in proximity to penetrating radiation.

Analyses of radiation dose and its health effects rely on scientific assumptions to compensate for lack of understanding and data. For example, a risk estimate may assume the existence of effective mitigative action and protective measures in preparation for an accident or other unplanned event (refer to Appendix A for information on risk assessment).

5.3.1 Radiological Effects from Normal Operations

Normal operations are those that proceed according to a predetermined plan. Most normal operations are routine. For example, the Site routinely emits very low concentrations of radioactivity from its HEPA filtered ventilation stacks. The dose of radionuclide emission (point-specific and diffuse sources) to the public from Rocky Flats in 1993 was 0.0016 mrem (EG&G, 1994b). In comparison, the annual natural background radiation for the Denver area is approximately 350 mrem (NCRP, 1987).

5.3.1.1 Risk to the Public from Normal Operations

Proposed Action

The proposed action involves brushing metal, size reduction of metal, thermal stabilization of oxide, transportation, packaging, and interim storage of SNM. These activities would slightly increase the potential for radionuclide air emissions. Under the proposed action, approximately 5,300 kg of SNM in solid form would be reduced in size, approximately 4,000 kg of plutonium in solid form would be brushed, and approximately 3,100 kg of SNM oxide would be thermally stabilized. Because of its chemical stability, approximately 1,300 kg of enriched uranium would not require thermal stabilization or brushing prior to packaging.

The estimated atmospheric emission potential for the proposed action is 0.31 grams (or 0.02 curies) of plutonium 239/240 and was calculated using the emission and control factors in the 40 CFR Part 61, Appendix D protocol. Actual emissions would be lower than those estimated because of the very conservative assumptions used in the calculations. Modeling the calculated emission to the public with the CAP88-PC computer dispersion code results in an estimated annual dose of 0.055 mrem for the anticipated seven-year consolidation effort. The annual Site emission limit for dose to the public is 10 mrem. In comparison, the public living in the Denver-metropolitan area receives an annual dose of approximately 350 mrem from naturally occurring radiation (NCRP, 1987).

The annual dose to the public in 1989, the last year of weapons production at Rocky Flats, was 0.0002 mrem (as measured from point-specific sources). The annual dose based on monitored emissions since cessation of weapons production has decreased steadily ever since (the 1993 dose, as measured from point-specific sources, was 0.000017 mrem). These annual doses were based on actual emission measurements, while the proposed action and no action alternative doses are based on conservative calculations. Measured emissions and the resulting annual dose to the public from the proposed action is projected to be 0.055 mrem for seven years. This annual dose is higher than the 1989 dose, but still far below the annual Site emission limit of 10 mrem.

No Action Alternative

The annual dose for the no action alternative was estimated by combining the 1993 radionuclide air emission measurements with the calculated doses expected for the Building 707 Thermal Stabilization and the Building 371/771 Liquid Stabilization Programs. Measured emissions and a resulting estimated annual dose of 0.0048 mrem for fifteen years compares closely with the 1989 dose, and is far below the annual Site emission limit of 10 mrem.

5.3.1.2 Risk to Workers from Normal Operations

Workers are exposed routinely to ionizing radiation at as low as reasonably achievable (ALARA) levels during normal operations at Rocky Flats. ALARA is an approach to radiation protection that minimizes and controls exposures to workers and the public to levels as low as reasonably achievable, taking into account social, technical, economic, and public policy considerations. Accordingly, worker doses are maintained below regulatory and contractual limits. Occupational Radiation Protection (10 CFR Part 835) regulatory limits apply to individual workers, and contractual limits with DOE for individual Rocky Flats workers are dramatically lower than these regulatory limits for individual workers in general.

Current regulatory limits are consistent with the 1987 National Council on Radiation Protection (NCRP) recommendations. The NCRP recommendations for occupational exposure have the intent of limiting radiation worker risk to a level that is reasonable and acceptable with respect to the value of the work being performed. The regulatory limit stated in 10 CFR Part 835 is 5.0 rem effective dose equivalent (EDE) annually. The contractual limit with DOE for individual Rocky Flats workers is 2.0 rem EDE annually. Rocky Flats has a far lower Administrative Control Level (ACL) of 0.75 rem EDE annually, and actual individual worker doses have been below the ACL. The ACL helps ensure that worker exposures are ALARA. Based on the radiogenic cancer assumptions in the 1987 NCRP recommendations, workers receiving the ACL dose experience an annual latent cancer fatality (LCF) risk of about one in ten thousand, which is the all-industry average.

Proposed Action

The proposed action would reduce radiological exposures for most Rocky Flats radiation workers by consolidating SNM into Building 371. Radiation sources would be relocated to areas where exposure to workers would be minimal. The central storage vault in Building 371 utilizes the fully automated stacker/retriever and shielded pallets to minimize worker interaction with SNM. Radiation workers would not need to enter the central storage vault during loading and inspection activities, further reducing radiological exposures.

The proposed SNM containers would require less frequent inventory inspection than the bimonthly inspections required in the export buildings because they provide for more stable storage than do the currently used containers. Although dose rates in the SNM consolidation vaults and vault-type rooms would be somewhat higher than in the export building vaults, an overall dose savings for the worker population would result from the reduced inspection frequency.

Dose is calculated as the dose rate multiplied times the length of exposure. For example, the SNM stored in the vault proposed for Room 3337 would produce dose rates in the range of 40 to 70 mrem per hour. In comparison, other vaults at the Site typically have dose rates less than 50 mrem per hour. However, the SNM consolidation effort reduces the frequency of inventory inspection by a factor of 24 from the current requirement. Thus, a dose savings would be realized for the workers performing the inventories. With the use of the stacker/retriever, the SNM could be inspected remotely inside the central storage vault which would further contribute to dose savings. Improved labeling of the interim storage containers would reduce the time required for inspection of a container, also contributing to dose savings.

The primary radiological risk to workers associated with the proposed SNM consolidation effort results from exposure in vaults and vault-type rooms. Collective exposure for the workers would be 43 person-rem EDE over a seven-year period; however, the annual dose of an individual worker would be less than the Site ACL.

Dose rates in rooms adjacent to the central storage vault would increase by less than 0.2 mrem per hour, and dose rates in the halls adjacent to other vaults and vault-type rooms in Building 371 would increase by less than 0.5 mrem per hour. The room adjacent to the central storage vault would have the highest occupancy rate at approximately six person-hours per day. Workers in that room would experience an annual collective dose increase of 0.3 person-rem EDE. The current median dose rate in the room is approximately 0.5 mrem per hour.

Because the room occupancy rate is divided among several workers, an increase of 0.2 mrem per hour would not place workers in danger of exceeding the current ACL. These figures are based on the conservative assumption of maximum room occupation.

As consolidation efforts progress, worker activity unrelated to the storage of SNM is expected to decrease in Building 371. This would counterbalance the increased dose rates during consolidation activities. The occupancy of the halls around the SNM storage areas would be small relative to that encountered in the same areas during loading, inspection, and surveillance activities. The estimated occupancy of these areas during consolidation activities is estimated at 170 person-hours per year. If the hall occupancy is also assumed to be 170 person-hours per year (a conservative assumption), a collective annual dose of less than 0.1 person-rem EDE would be received.

Dose rates in areas near the SNM storage vaults and vault-type rooms, including laboratories, could rise from current levels to more than the 0.5 mrem per hour, the design criterion for routine occupation. As SNM consolidation activities draw to conclusion, however, the tasks in the radiation areas would diminish. Design and job reviews would ensure that occupational exposures of workers in these areas remain ALARA.

The dose estimates for SNM consolidation conservatively assume that the plutonium is 75 years old and that it all is in oxide form. Over time, plutonium oxide produces additional neutrons and secondary photons, which results in higher potential dose rates than from SNM in metal form. Under the proposed action, most of the Rocky Flats worker population would avoid this dose rate increase because the SNM would be removed from the buildings in which they work.

No Action Alternative

Many of the safety systems in the older buildings require an inordinate amount of frequent preventative and corrective maintenance. Degradation of building vital safety systems (VSSs) increases the radiation exposure of the material handlers and support personnel. Maintenance of the VSSs under the no action alternative would require work on five buildings as compared to only one if the proposed action of consolidation of SNM in Building 371 is selected.

By leaving SNM stored in the export buildings, workers would realize a dose savings from not conducting consolidation activities. However, the additional dose from the current inventory inspection frequency and increased maintenance activities in radiation areas would be greater over time than from the initial dose savings. Radiological risk associated with the no action alternative is illustrated in Figure 5-2.

5.3.2 Exposure from Radiological Accidents

The following sections address risk to the public and workers from radiological accidents.

5.3.2.1 Risk to the Public from Accidents

Accidents may occur during the processing and movement of SNM that have the potential for exposure of the public to radiological contamination. The accidents considered include fires, explosions, spills, criticalities, and external events such as truck and airplane crashes, earthquakes, extreme winds, tornados, floods, snow loading, and lightning.

Public health effects from radiological contamination are derived from the number of grams of SNM that potentially could be released by a particular accident scenario. The health effects from uranium are orders of magnitude lower than those from plutonium; therefore, the following discussion focuses entirely on plutonium. Assumptions are made concerning the physical processes that can release plutonium from its container or enclosure, the amount of material that can become airborne, the fraction of this material that can enter and be retained by the body, and the atmospheric transport properties of the material. These assumptions are based on experimental data and engineering judgment. Systems and structures are credited for mitigation of consequences when it is considered appropriate to assume their availability during the accident. Similarly, accident probabilities are derived from equipment and human failure data.

Risk to the public from plutonium exposure is a combination of the probability and consequence of accidental release. Two different accidents may have the same overall risk, even though one has a high probability of occurrence but a small consequence, while the other accident may have a low probability of occurrence and a large consequence.

The estimates of risk to the public for SNM consolidation made use of safety analyses previously generated for similar operations, including those documented in the Final Environmental Impact Statement for Rocky Flats Plant Site (DOE, 1980) and Final Safety Analysis Reports (EG&G, 1980s). The safety analyses evaluated the probability of loss of confinement, potential pathways to the environment, and health effects resulting from those releases. The existing analyses required some adjustment of accident parameters to adapt them specifically to the proposed action and the no action alternative. The adaptations represent the entire range of dominant accident possibilities for all facilities and constitute the relative public risk estimate for selected bounding accidents. This analysis is described in detail in Safety Analysis in Support of the Environmental Assessment for Consolidation and Interim Storage of SNM in Building 371 (EG&G, 1995).

Proposed Action

The proposed action would reduce the risk to the public in the long term. Figure 5-1 illustrates how activities necessary for consolidation and processing of SNM would cause an initial rise in risk to the public. These include size reduction of metal, brushing of metal, thermal stabilization of oxide, packaging, and transportation; all of which increase the probability of operational accidents during the seven-year duration of these activities. The risk to the public for the most severe accident of each type considered is presented in Table 5-1.

The probability of operational accidents would decrease after consolidation and processing of SNM. Interim storage of the material in Building 371 would involve minimal handling of SNM, particularly after the introduction of the proposed storage containers for oxide and metal. Once the proposed action is completed, the SNM stored at Rocky Flats would represent a lower risk to the public.

The probabilities for the occurrence of accident categories (related to the consequences to the public and workers) may be different because the bounding accidents and/or the dynamics of exposure may be different for the two groups.

A fire during size reduction of plutonium metal in Building 707 represents the bounding fire accident with the greatest release of plutonium into the environment (see Appendix A for an explanation of bounding accident scenarios). It was assumed conservatively that simultaneous loss of normal and alternate offsite electric power and the building's emergency diesel generator would occur, resulting in the loss of the Building 707 ventilation and HEPA filtration systems for gloveboxes and process rooms. It also was assumed that pyrophoric materials would spontaneously ignite and breach the glovebox. Without active ventilation, a portion of the release would migrate directly to the outside environment through a crack around personnel egress doors. This scenario has a probability of occurrence of 6x10^-5 per year with a dose to the public of 1x10^-2 rem EDE. The resultant latent cancer fatalities (LCFs) among the population within 50 miles from the Site for this accident scenario is 1x10^-3.

Table 5-1. Consequences to the Public* from Bounding Accidents.

Bounding Accident Category	Proposed Action: Probability of Occurrence (per year)	No Action Alternative: Probability of Occurrence (per year)	Proposed Action: No. of Latent Cancer Fatalities Among Population <50 miles from Site	No Action Alternative: No. of Latent Cancer Fatalities Among Population <50 miles from Site
Fire	6x10^-5	2x10^-6	1x10^-3	3x10^-4
Explosion	5x10^-5	5x10^-5	4x10^-2	4x10^-2
Spill	1x10^-3	1x10^-4	4x10^-3	5x10^-4
Criticality	1x10^-4	1x10^-4	6x10^-4	6x10^-4
Intra-Building Transfers	1x10^-4	1x10^-4	5x10^-4	5x10^-4
Onsite Truck Transportation	9x10^-7	9x10^-8	8x10^-1	5x10^-2
Natural Phenomena	1x10^-3	1x10^-3	1x10^-1	1x10^-1
Airplane Crash	4x10^-8	4x10^-9	5x10⁰	5x10⁰
Severe Accident	8x10^-4	8x10^-4	6x10^-1	9x10^-1

Beyond Design Basis

*Risk to the public is assumed conservatively as equal to that of a hypothetical person who lives continuously at a point on the Site boundary where exposure to the public from accidents would be the highest.

See Appendix B, Useful Information, for Examples of Scientific Notation Usage

The bounding explosion accident is the ignition of leaked acetylene from an oxy-acetylene welding operation with subsequent damage to a glovebox where metal items are being reduced in size. In Building 707, the force of the explosion was assumed to breach the building confinement systems by blowing open personnel egress doors. This would cause an unfiltered release of plutonium into the environment. The probability of this scenario occurring is 5x10^-5 per year with a dose to the public of 4x10^-1 rem EDE. The resultant LCFs among the population within 50 miles from the Site for this accident scenario is 4x10^-2. (The scenario for Building 371 is equivalent with the exception that all releases would be filtered and the resulting in doses would be orders of magnitude lower.)

The bounding spill accident results from a container of plutonium oxide being dropped from the loading/receiving dock which would cause an unfiltered release. Transfer containers are designed to withstand anticipated incidents such as being dropped from the dock or truck; however, it was assumed conservatively that the dropped container would have an improperly sealed lid as a result of human error. The dock doors were assumed to be open at the same time, allowing direct dispersal of plutonium into the environment. The probability of this scenario occurring is 1x10^-3 per year with a dose to the public of 4x10^-2 rem EDE. The resultant LCFs among the population within 50 miles from the Site for this accident scenario is 4x10^-3.

The Rocky Flats occurrence reporting data base has not documented one criticality accident in the 40-year history of operations. Criticality safety limits are strictly enforced and are very specific as to the quantity and mass of fissile material materials allowed in a given location. These measures have successfully prevented such an occurrence at Rocky Flats.

The bounding criticality accident assumed a violation of double contingency, allowing sufficient quantities of plutonium metal to be placed in a configuration that would initiate a criticality. (Double contingency is a practice of designing a process such that no single accident will result in a criticality.) The probability of this scenario occurring is 1x10^-4 per year with a dose to the public of 3x10^-2 rem EDE. The resultant LCFs among the population within 50 miles from the Site for this accident scenario is 6x10^-4. The risk from criticality accidents would decrease sharply after completion of consolidation efforts, reflecting the reduced frequency of handling these materials.

Movement of plutonium on carts was analyzed for accidents including fires inside and outside plutonium containers, explosions, spills, and criticalities. The bounding accident for intra-building transfers is a fire initiated by pyrophoric plutonium while moving carts in Building 778. The probability of this scenario occurring is 1x10^-4 per year with a dose to the public of 5x10^-3 rem EDE. The resultant LCFs among the population within 50 miles from the Site for this accident scenario is 5x10^-4

The bounding accident for onsite truck transportation is a severe collision of a truck transporting plutonium oxide. The crash was assumed to breach the diesel fuel tank and ignite a fire which engulfs the entire truck. Half of the containers were assumed to be breached and release part of their contents into the environment. The probability of this scenario occurring is 9x10^-7 per year with a dose to the public of 2x10⁰ rem EDE. The resultant LCFs among the population within 50 miles from the Site for this accident scenario is 8x10^-1.

Natural phenomena events include earthquakes, extreme winds, and tornados. The bounding natural phenomena scenario is an earthquake of 0.14 gravity bedrock acceleration (approximately 6.0 on the Richter scale). This would result in the loss of offsite power and onsite emergency diesel power and portions of Building 707 would collapse. The probability of this scenario occurring is 1x10^-3 per year with a dose to the public of 1x10⁰ rem EDE. The resultant LCFs among the population within 50 miles from the Site for this accident scenario is 1x10^-1.

Over the long term, natural phenomena events dominate risk to the public. These events have a low probability of occurrence and a large consequence. Consolidation of SNM into Building 371 would lower the Site risk because the building meets the design basis requirements for these events. Therefore, risk to the public would be substantially reduced over the seven-year period as preliminary activities are completed and material is consolidated into Building 371.

Analyses were performed for the crash of an airplane into Building 707 (Module J) and into a new vault in Building 371. In the bounding accident, a small plane would penetrate some rooms on the main floor of either building. The accident involves plutonium metal and the analyses take no credit for sealed containers. The probability of this scenario occurring is 4x10^-8 per year with a dose to the public of 2x10¹ rem EDE. The resultant LCFs among the population within 50 miles from the Site for this accident scenario is 5x10⁰.

A severe earthquake of 0.21 gravity bedrock acceleration (greater than 6.5 on the Richter scale) was analyzed which is beyond the design basis for the Site. This earthquake would collapse all of Building 707, while Building 371 would remain intact. The probability of this scenario occurring was estimated to be 8x10^-4 per year with a dose to the public of 6x10⁰rem EDE from the collapse of Building 707. The resultant LCFs among the population within 50 miles from the Site for this accident scenario is 6x10^-1.

No Action Alternative

Under the no action alternative, there would be an ongoing need to move SNM, brush metal, and stabilize oxides. Dispersible forms of plutonium oxide would accumulate in unsealed containers while safety systems would continue to degrade. Risk to the public would be smaller initially for the no action alternative (as illustrated in Figure 5-2), but it rises to exceed the risk of the proposed action over time.

Risk from fire, explosion, and spill accidents associated with the no action alternative would be lower for operational accidents during the period of SNM consolidation and processing because the material would not be handled to the extent expected under the proposed action. The SNM stored in the export buildings are inside gloveboxes and would have a greater probability of being involved in a room fire or explosion than would material stored in the central storage vault in Building 371. Gloveboxes in the export buildings are susceptible to fires from a number of potential initiators.

The probability of a criticality accident occurring under the no action alternative would be similar to that of the proposed action. The SNM would continue to be handled on a regular basis as part of the ongoing Thermal Stabilization Program (DOE, 1994a).

The risk from onsite transport of plutonium metal and oxide would be somewhat lower initially under the no action alternative because fewer containers of pyrophoric oxide would be moved by truck from Building 371 to Building 707 for stabilization and packaging. This would reduce the probability of the material being involved in a truck fire. Although the probability of a truck fire is somewhat greater when carrying pyrophoric material than when carrying stabilized oxide, the overall risk is lower because the amount of pyrophoric material permitted in each container is only 1 kg as compared to 5 kg of stabilized material.

Natural phenomena events dominate risk to the public from the export buildings. These buildings are susceptible to natural phenomena such as high winds, tornados, and earthquakes. Various structural analyses have confirmed that the export buildings could collapse, causing plutonium to be released directly to the atmosphere. Building 371 is designed to withstand these natural forces. Plutonium released by an earthquake inside the intact Building 371 structure must pass through two stages of HEPA filters which would reduce public exposure by six orders of magnitude.

The risk due to an airplane crash is similar under both the proposed action and the no action alternative, partly because it was assumed that all containers were vulnerable during the ensuing fire. However, if test results for the proposed storage containers demonstrate that they can withstand a 30-minute fire, then public dose from this accident would be lower by two to three orders of magnitude for the proposed action.

Relative Risk to the Public

The total relative risk for each of the accidents described above is summed in Table 5-2 for the entire Site for both the proposed action and the no action alternative. Only the risk for those previously analyzed accidents of each type have been included in this total. Relative risk does not represent actual risk, but rather the relative risk for a specific accident sequence as it occurs in each building. The accidents in Table 5-2 do not fully account for potential additional doses from equipment degradation and accumulation of dispersible forms of plutonium oxide in unsealed containers in the export buildings. The relative risk is dominated over the long term by radiological releases from natural phenomena events. During the short term (i.e., the seven-year period of SNM consolidation and processing) the relative risk would be dominated by operational accidents such as spills of plutonium oxide.

5.3.2.2 Risk to Workers from Accidents

Physical and administrative radiological controls minimize the frequency of radiological accidents, and mitigation and detection systems minimize accident consequences. The mitigation and detection systems, together with radiological controls, minimize exposures from anticipated accidents, although large radiation doses and fatalities are possible during some accidents.

Proposed Action

Risk to the worker is assessed for the same accidents as for the public (refer to Section 5.3.2.1). The probabilities for such accidents in most cases are very similar for the worker and the public, but the consequences are substantially higher for workers because of their close proximity to an accident at the Site.

Table 5-2. Relative Risk to the Public* from Accidents.

Accident Category	Proposed Action: Relative Risk to the Public (rem/yr)	No Action Alternative: Relative Risk to the Public (rem/yr)
Fire	<2x10^-6	<2x10^-8
Explosion	2x10^-5	<7x10^-5
Spill	2x10^-4	1x10^-5
Criticality	6x10^-6	2x10^-5
Transportation (Intra-Building & Onsite Truck)	3x10^-6	7x10^-7
Natural Phenomena	1x10^-3	3x10^-3
Airplane Crash	7x10^-7	9x10^-7
Severe Accident Beyond Design Basis	5x10^-3	3x10^-2
Composite Risk Total	6x10^-3	3x10^-2

See Appendix B, Useful Information, for Examples of Scientific Notation Usage

Radiation exposure from an accident would be greatest for workers in the immediate vicinity of the accident. Other Rocky Flats workers located away from the accident would receive exposures similar to, but greater than, exposure to the public. During the preparation and processing of SNM for consolidation, an increased work activity level in the presence of SNM and an increased SNM inventory in the consolidation areas would temporarily increase the risk from the proposed action.

Accidents could release radioactive material directly into the environment of the immediate workers, making the material available for inhalation as an aerosol. Accidents are most likely to occur during and prior to SNM repackaging and would present the greatest risk for the worker population.

Radiological controls, including gloveboxes and other secondary containments, minimize the probability of release to the workers environment. Selective alpha air monitors (SAAMs) and room air ventilation are required detection and mitigation systems, respectively. SAAM alarms notify workers when airborne radioactive material is present, and process areas in Building 371 are ventilated with eight room-air volumes per hour.

Radiation exposure events have a low probability of occurrence and their expected contribution to the total dose of the worker population is minimal. During consolidation activities, the probability and consequence of accidents involving SNM would increase from current levels. The consequences to workers from bounding accidents under the proposed action are shown in Table 5-3.

A dose of 400 to 500 rem received within 24 hours is normally considered fatal in 50 percent of the population. However, plutonium gives a very small daily exposure. An overall high dose results from the tendency of plutonium to localize in the bone, providing dose over a lifetime, but with very little received during any 24-hour period.

The bounding fire accident with the most serious worker consequences is from a dock fire in Building 707 which is initiated by maintenance activities such as welding or by an electrical short. The probability of occurrence is 2x10^-4 per year and the dose to a worker in the immediate vicinity is 3x10² rem EDE. The resultant LCFs among Rocky Flats workers for this accident scenario is 6x10^-1.

The bounding explosion accident is the ignition of leaked acetylene from an oxy-acetylene welding operation with subsequent damage to a glovebox where metal items are being reduced in size. This accident has a probability of occurrence of 5x10^-5 per year and would result in fatalities to workers in the immediate vicinity due to shrapnel and a shock wave accompanying the explosion.

Accidents involving the spill of plutonium oxide dominate risk to the worker due to inhalation of aerosolized plutonium. This type of accident has a relatively high probability of occurrence because of the need to handle the material on a regular basis in order to perform the proposed brushing of metal, size reduction of metal, thermal stabilization of oxide, and packaging activities. However, the bounding spill accident for worker risk assumed the discharge of a weapon by a security guard inside a vault. The probability of this scenario occurring is 9x10^-3 per year. The projectile is assumed to rupture a container of plutonium oxide, providing a dose to the worker of 8x10²rem EDE. The resultant LCFs among Rocky Flats workers for this accident scenario is 2x10⁰.

The bounding criticality accident assumed a violation of double contingency, allowing sufficient quantities of plutonium metal to be placed in a configuration that would initiate a criticality. (Double contingency is a practice of designing a process such that no single accident will result in a criticality.) The criticality would result in lethal doses of prompt gamma and neutron radiation to workers in the immediate vicinity of the criticality. The probability of this scenario occurring is 1x10^-4 per year. The risk from criticality accidents would decrease sharply after completion of consolidation efforts, reflecting the reduced frequency of handling these materials.

Movement of plutonium on carts was analyzed for accidents including fires inside and outside plutonium containers, explosions, spills, and criticalities. The bounding accident for intra-building transfers is a fire initiated by pyrophoric plutonium while moving carts in Building 778. The probability of this scenario occurring is 1x10^-4 per year and would result in a worker dose of 9x10⁰ rem EDE. The resultant LCFs among Rocky Flats workers for this accident scenario is 3x10^-2.

Table 5-3. Consequences to Workers from Bounding Accidents.

Bounding Accident Category	Proposed Action: Probability of Occurrence (per year)	No Action Alternative: Probability of Occurrence (per year)	Proposed Action: No. of Latent Cancer Fatalities Among Workers	No Action Alternative: No. of Latent Cancer Fatalities Among Workers
Fire	2x10^-4	2x10^-4	6x10^-1	1x10^-1
Explosion	5x10^-5	5x10^-5	Fatalities to Workers in Immediate Vicinity	Fatalities to Workers in Immediate Vicinity
Spill	9x10^-3	9x10^-3	2x10⁰	1x10⁰
Criticality	1x10^-4	1x10^-4	Fatalities to Workers in Immediate Vicinity	Fatalities to Workers in Immediate Vicinity
Intra-Building Transfers	1x10^-4	1x10^-4	13x10^-2	3x10^-2
Onsite Truck Transportation	9x10^-7	9x10^-8	7x10^-1	2x10⁰
Natural Phenomena	1x10^-3	1x10^-3	Fatalities from Building Collapse and Radiation	Fatalities from Building Collapse and Radiation
Airplane Crash	4x10^-8	4x10^-9	Fatalities from Falling Debris, Radiation, and Fire	Fatalities from Falling Debris, Radiation, and Fire
Severe Accident Beyond Design Basis	8x10^-4	8x10^-4	Fatalities from Falling Debris	Fatalities from Falling Debris

See Appendix B, Useful Information, for Examples of Scientific Notation Usage

The bounding accident for onsite truck transportation is a severe collision of a truck transporting plutonium oxide. The crash was assumed to breach the diesel fuel tank and ignite a fire which engulfs the entire truck. Half of the containers were assumed to be breached and release part of their contents into the environment. This accident has a probability of occurrence of 9x10^-7 per year and would result in a worker dose of 2x10³ rem EDE. The driver of the truck also could be killed in such a violent collision, although the short distances involved and the presence of escort vehicles should preclude the attainment of the necessary high speeds. The resultant LCFs among Rocky Flats workers for this accident scenario is 7x10^-1.

Natural phenomenon events include earthquakes, extreme winds, and tornados. The bounding natural phenomena scenario is an earthquake of 0.14 gravity bedrock acceleration (approximately 6.0 on the Richter scale) and has a 1x10^-3 per year probability of occurrence. Building 371 was designed to withstand an earthquake of greater than 6.0 on the Richter scale. However, office areas were not constructed to the same criteria and some workers are located in office areas that would be expected to collapse. Fatalities would occur from falling debris and exposure to radiation. Workers in the process area of Building 371 are well protected from falling debris, and the ventilation systems are designed to remain operable during and after a design basis earthquake.

The airplane crash accident analysis was prepared as an emergency planning tool and does not detail potential worker risks. Workers in the immediate vicinity of the accident would experience no radiation exposure from such an event because most vaults are not routinely occupied. Fatalities would occur from falling debris, burning fuel, and exposure to radiation. The probability of this scenario occurring is 4x10^-8 per year.

A severe earthquake of 0.21 gravity bedrock acceleration was analyzed and represents the bounding severe accident beyond design basis for workers. This earthquake would collaspe all of Building 707, while Building 371 would remain intact. The probability of this scenario occurring is 8 x 10^-4 per year. Radiation exposures to workers were not calculated since these consequences would be eclipsed by fatalities caused by falling debris.

No Action Alternative

Under the no action alternative, there would be an ongoing need to move SNM, brush metal, and stabilize oxides. Dispersible forms of SNM would accumulate in unsealed containers while safety systems would continue to degrade. Workers in the immediate vicinity of an accident generally would receive the highest dose. Workers at the Site who are not involved in the activity would experience potentially larger doses than the general public.

Possible accidents would release radioactive material directly into the immediate worker's environment, and the resulting SNM aerosol would be available for inhalation. The greatest risk to the worker population would involve release during inspection and surveillance of the SNM.

This analysis does not quantify the risk for each of the operational accidents associated with the no action alternative over the duration of interim storage period. Therefore, trends are qualitatively assessed by comparing the results of existing safety analyses. The comparison shows that the risk of radiological accidents would be greatest for the workers inspecting SNM in the current storage areas while other workers, not in the SNM storage areas, would experience an accident probability similar to the general public but with higher doses.

Over time, the degradation of safety systems and accumulation of dispersible forms of SNM in unsealed containers would lead to an increase in risk from fires, spills, and explosions. The anticipated failure of the current SNM storage containers would lead to an increased probability of accidents. The consequences of natural phenomena events also would increase because a larger fraction of the inventory would have been converted to oxide and contained in vulnerable containers.

The scenarios with the greatest consequences are natural phenomena events such as high winds, tornados, and earthquakes. Under the no action alternative, SNM would remain for many years in facilities which were not built to withstand these events; therefore, worker risk would increase with time. The probability of worker fatalities also would be greater in future years under the no action alternative because workers would continue to be required onsite to conduct the ongoing inspection and stabilization activities in many different buildings.

5.4 Cumulative Effects

The cumulative effect of the proposed consolidation and interim storage of SNM in Building 371 at Rocky Flats would be to reduce the risks to both workers and the public over the long term. Other effects would include a potential for a slight initial increase in annual emissions of radionuclides. These emissions would be far below the allowable Site emission limit. An estimated 1,040 cubic yards of TRU waste and 130 cubic yards of low-level waste would be generated as a result of the proposed action activities. Storage space for this waste, over the 10 to 15 year period considered for the proposed action, would continue to diminish.

Individual worker radiation exposure would not only remain well within DOE requirements of 5 rem EDE annually, but also within the more stringent Rocky Flats ACL of 0.75 rem EDE annually. Effects due to normal operations on the public, expressed in terms of an increase in the probability of dying from cancer, are essentially zero (less than 1.5 chances in one trillion).

5.5 Summary of Effects

The proposed action would require only minimal exterior construction activities, and most facility modifications would be inside an existing building. Therefore, impacts upon the natural environment would be minimal. Under normal operating conditions, there would be minor releases of non-radiological air pollutants associated with local transportation. There would be no adverse effects on water resources, floodplains, wetlands, threatened or endangered species, cultural resources, or other Site features. The low-level and TRU waste generated by the proposed action activities are not expected to result in any measurable environmental effects because of strict adherence to safety procedures and requirements for storing waste at Rocky Flats. A summary comparison of environmental effects resulting from the proposed action and no action alternative is found in Table 5-4.

Initially, the radiological risk from the proposed action during its implementation period is greater than from the no action alternative. After this initial increase in risk, the level of risk decreases below that of the no action alternative for the remainder of the interim storage period. Actual adverse effects upon human health are unlikely to result from implementation of either the proposed action or the no action alternative.

Table 5-4. Summary of Environmental Effects from the Proposed Action and the No Action Alternative.

Alternative	Worker Exposure from Normal Operations	Public Exposure from Normal Operations	Accident Risk	Waste Generated	Effects On Wetlands, Floodplains, and Threatened & Endangered Species
Proposed Action	Dose would increase in short term; decrease after consolidation (Figures 5-1 and 5-2)	0.055 mrem annual dose for 7 years	Risk would increase in short term; decrease after consolidation (Figures 5-1 and 5-2)	1,040 cu. yds. TRU waste and 130 cu. yds. of low-level waste generated	None
No Action	Dose would increase relative to increased level of maintenance and SNM inventory	0.0048 mrem annual dose for 15 years	Risk is lower initially, increasing over time (Figure 5-1 and 5-2)	510 cu. yds. TRU waste generated due to normal, ongoing activities	None

6.0 AGENCIES AND PERSONS CONSULTED

None.

7.0 REFERENCES

ASI: Wetlands Assessment, Rocky Flats Site. Advanced Sciences, Inc., April 1990.
DOE, 1980: Final Environmental Impact Statement, Rocky Flats Plant Site, DOE/EIS-0064. U.S. Department of Energy, April 1980.
DOE, 1994: Notice of Intent to Prepare a Programmatic Environmental Statement for Storage and Disposition of Weapons-Usable Fissile Materials, 59 FR 31985. U. S. Department of Energy, June 1994.
DOE, 1994a: Environmental Assessme

Weapons of Mass Destruction (WMD)

EA-1060; Environmental Assessment Consolidation and Interim Storage of Special Nuclear Material at Rocky Flats Environmental Technology Site, Rocky Flats Field Office, Golden, Colorado

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES