4.12 INTRASITE TRANSPORTATION
4.12.1 Affected Environment
This section describes the intrasite transportation and handling of hazardous materials at Pantex Plant. Within Pantex Plant Site, approximately 30,000 transfers of nuclear and explosive materials take place each year, many of which are transported between zones, particularly Zones 4, Zone 11, and 12, and between buildings in these zones. These materials include nuclear explosives, nuclear components, tritium, radioisotopic thermoelectric generators (RTGs), depleted uranium, high explosive(s) (HE) components and materials, chemicals, and other hazardous materials. The materials involved in these latter transfers do not involve an external radiation hazard as do weapons, pits, or to a lesser extent canned subassemblies (CSAs).
In addition, low-level waste (LLW), low-level mixed waste (LLMW), and other hazardous wastes are transported onsite for storage, treatment, and disposal. Interzonal transfers between Zones 4, 11, and 12 are carried out on paved roads. Transportation between buildings in Zones 11 and 12 is frequently carried out via enclosed ramps. Typical vehicles and equipment used for transportation on roads include hardened trailers, Safe Secure Tractor Trailers (SSTs), flatbed trailers, vans, trucks, and tow motors. Transfer of materials via ramps is carried out by forklifts and pallet jacks.
The following subsections further describe the intrasite hazardous materials transportation activities at Pantex Plant. Worker doses resulting from transportation activities are also provided in these subsections to determine human health risks analyzed in section 4.14, Human Health.
4.12.1.1 Onsite Transfers of Radioactive Material
Onsite transfer of radioactive material is governed by DOE orders and Pantex-specific standards. The Transportation and Staging Department is responsible for transfers of nuclear explosives and nuclear explosive components between zones. The inventory control section of the Production Stores Department is responsible for transfers of nuclear explosives and nuclear explosive components between bays and cells within buildings in Zone 12. The Waste Operations Department is responsible for transportation of radioactive wastes onsite.
Nuclear ExplosivesWithin zones, nuclear explosives are transported on paved roads and covered walkways (ramps) using an electric forklift. During onsite transfers, nuclear explosives are retained in weapons-specific handling gear (H-gear) containers. Nuclear explosives within H-gear containers produce weapons system-specific external radiation hazards. Certain types of nuclear explosives are transported as a complete unit and are attached to their H-gear; this type of nuclear explosive has a bounding dose rate of 8 millirem per hour at 1 meter. Nuclear warheads, however, are contained within system-specific H-gear packages; this type of nuclear explosive has a bounding dose rate of 50 millirem per hour at the surface of the package. H-gear containers are towed between locations or lifted by the forklift and driven to locations. The speed limit for nuclear explosive transfers within ramps is 8 kilometers (5 miles) per hour.
Nuclear explosives are transported between zones within either hardened trailers or SSTs. SSTs are similar in appearance to commercial tractor trailers but are equipped with unique safety and safeguards features that prevent unauthorized cargo removal and minimize the likelihood of an accidental radioactive material release. Hardened trailers are similar in design to SSTs but have fewer security features than SSTs, which are designed for offsite transport. Table 4.12.1.11 shows the number of nuclear explosive and nuclear explosive component interzone transfers for 1993.
PitsAt the point of removal from a weapon, pits are swipe-tested to ensure that there is no surface radioactive contamination. Pits are then placed in ALR8 containers and sealed with a tamper-indicating device. A pit within a container presents an external radiological hazard that is weapons system-specific. A typical dose rate is 3 millirem per hour at 1 meter for the ALR8 container. Within Zone 12, pit transfers related to component testing, weapon assembly, or weapon modifications are accomplished with electric forklifts and special nuclear material (SNM) tie-down pallets.
All pits are expected to be staged using Stage Right techniques and equipment by December 1996. Stage Right techniques and equipment would enable the stacking of pit containers with the containers long axis oriented horizontally within a steel pallet. Figure 4.12.1.11 is an artists rendition of a Stage Right magazinemagazine. These staging techniques and equipment have simplified pit transfers and reduced the need for entrance into magazines by personnel and their exposure to radiation. Pits being transferred to Zone 4 West for staging are placed at the disassembly point within a Stage Right pallet (either four or six containers per pallet) and, using an electric forklift, loaded into a pallet trailer, which can carry 24 pit containers. The pallet trailer is driven to Zone 4 West and parked at the storage magazine. In the past, hardened trailers and SSTs have been used to move pits between zones, and they could be used in the future.
Prior to the placement of pit pallets into a magazine, a temporary staging ramp with a pallet turner is installed. This ramp ensures that the Stage Right forklift is properly positioned to place the pit pallets within the storage magazine. Once the ramp installation is complete, a standard forklift removes the pallet from the pallet trailer and places it on the pallet turner with the pit containers in the vertical position (Figure 4.12.1.12). The pallet turner is then rotated 90 degrees so that the pit containers are in the horizontal position. A shielded Stage Right forklift (shown in Figure 4.12.1.11), or an automated guided vehicle, is then driven onto the staging ramp to the pit turner, where the forklift boom lifts the pallet off the turner. The forklift is then driven between the permanently installed guiderails inside the magazine to the desired location. Pits are retrieved from a storage magazine in a similar manner.
Figure 4.12.1.1-1.--Stage Right Maintenance.
Figure 4.12.1.1-2.--Placement of Stage Right Pallet on Pallet Turner.
Canned Subassemblies(CSA)At the point of removal from a weapon, canned subassemblies (CSAs) which may contain highly enriched uranium (HEU)highly enriched uranium, are either packaged in sealed steel containers, fastened onto metal frames, or staged in plywood boxes. A packaged canned subassembly (CSA)CSA produces a weapons system-specific external radiation hazard. A packaged CSA has a bounding dose rate of 0.2 millirem per hour at 1 meter. These components are loaded onto SNM tie-down pallets and transferred by electric forklift to an approved storage facility to await transfer to either the Y-12 PlantY-12 Plant (at Oak Ridge Reservation) for final disassembly or Zone 4 for temporary staging. CSA transfers related to component testing, weapon assembly, or weapon modifications within Zone 12 are accomplished using either SNM tie-down pallets or special pallets and electric forklifts.
CSAs ready for transfer to Zone 4 are moved by electric forklift to a loading dock within Zone 12, where they are loaded into a hardened trailer or SST, tied down within the trailer, and driven to a storage magazine within Zone 4 West. Upon arrival at the magazinemagazine, CSAs are placed on a pallet and driven into the magazine using an electric forklift. CSAs are placed on the floor using the forklift, a manual hand truck, or a small hydraulic truck. CSAs are retrieved from a storage magazine in the same manner.
Radioisotopic Thermoelectric GeneratorsAt the point of removal from a weapon, Radioisotopic Thermoelectric Generator (RTG)RTGs are placed in an approved container. The containers are then transported to an approved storage facility to await transfer to Los Alamos National Laboratory. RTGs within containers do not present a radiological hazard. RTG transfers related to component testing, weapon assembly, or weapon modifications within Zone 12 are accomplished with electric forklifts or carts using SNM tie-down pallets or wire baskets.
Tritium ReservoirsAt the point of removal from a weapon, tritium reservoirs are placed in either Kennedy Kits, metal suitcases, or H1616 containers. The reservoirs within the container do not present a radiological hazard. The container is transported to the Tritium Staging Facility to await transfer to the Savannah River Site (SRS)Savannah River Site. Some reservoirs are processed through a separate facility prior to delivery to the Tritium Staging Facility. Reservoir transfers occur in a wire basket secured to either a forklift or the bed of an electric cart. Tritium reservoir transfers related to component testing, weapon assembly, limited-life component replacements, or weapon modifications within Zone 12 are accomplished in a similar manner.
Low-Level and low-level mixed waste (LLMW)Mixed Radioactive Wastes
Both low-level and mixed radioactive wastes are transported from the generation point to the central collection area in Building 1242. Upon approval for shipment to Building 1242, the waste is loaded onto a flatbed or stakebed truck, secured with tie-downs, and relocated to the storage facility truck dock. At the truck dock, the waste package is checked for damage and proper paperwork and added to the facility inventory. From Building 1242, radioactive wastes are transferred to an onsite storage facility using a flatbed or stakebed truck. These storage facilities include Building 119N, Building 117N Pad, Zone 4 East Magazines 50 and 56, and 25 Conex Boxes.
Transportation ManagementMovements of nuclear explosives and nuclear components are coordinated with and tracked by the SNM control center via a secure telephone system. A custodian is assigned to oversee transfer operations. For Zone 12 transfers, a walker-spotter walks in front and directs all traffic, including foot traffic, to stop until the vehicle safely passes. Signs and corridor mirrors help alert drivers to any approaching hazards during transfers. The amount of combustible material allowed in ramps used for nuclear material transfers is strictly limited. The speed limit for vehicles carrying nuclear materials within and between buildings in Zone 12 is 8 kilometers (5 miles) per hour. The speed limit for SNM transfers between Zones 4 and 12 is 32 kilometers (20 miles) per hour. All personnel involved in these transfers are required to wear dosimeters. All Transportation and Staging Department personnel handling pit containers are required to wear lead aprons and lead-lined gloves.
4.12.1.2 Zone 4 West Nuclear Material Staging Operations
The Transportation and Staging Department is responsible for Zone 4 operations involving nuclear explosives and nuclear explosive components. The bulk of the activity associated with the Zone 4 West staging magazines involves material movements to and from the production areas in Zone 12, as discussed in section 4.12.1.1. Other activities that take place in Zone 4 West include:
- The performance of inventories and inspections of the SNM contents of the magazines.
- The documentation of the arrival or departure of each SNM item with the SNM control room.
- The unloading of weapons and nuclear components from arriving SSTs.
- The loading of weapons and nuclear components into departing SSTs.
- The loading of canned subassembly (CSA)CSAs into departing SSTs.
Arriving weapons, Joint Test Assembly (JTA)Joint Test Assemblies, and Test Beds are driven to Zone 4 West, where they are unloaded in front of a storage magazinemagazine. Weapons contained in SSTs are unloaded as follows:
- A flatbed trailer with an electric forklift on the bed is backed up to the open SST trailerthe flatbed trailer is a 12-meter (40-foot) commercial trailer with the same bed height as the SST and sideboards to prevent objects on the bed from falling off.
- The tie-downs securing the nuclear explosive within the SST are removed.
- The forklift on the flatbed trailer drives into the SST, removes the H-gear containing the weapon, and places it on the flatbed trailer.
- An electric forklift on the ground removes the H-gear containing the weapon from the flatbed trailer and drives it into the magazine for storage.
The unloading of nuclear explosives using H-gear containers with rollers or casters is an exception to the above description. In this case, the H-gear containing the weapon is rolled to the edge of the SST, where it is placed on the ground by an electric forklift and rolled into the magazine. In addition, certain weapon systems are too heavy to be unloaded by either of the above methods. In such cases, a loading dock within Zone 4 is used.
DOE requires safeguards and security programs at facilities handling SNM. At Pantex Plant, this program requires the periodic inventory of magazines containing nuclear explosives and nuclear explosive components. The frequency of inventory for pit staging magazines is dictated by the staging class of the magazine. Pit staging magazines are divided into two classes, normal and exempt magazines. Normal staging magazines contain reserve components for existing weapon systems. For these magazines the maximum time between inventories would be 12 months and 1 week. Exempt magazines contain components that are not expected to be reused. For these magazines the maximum time between inventories would be 21 months and 1 week.
Inventories in the magazines when pit containers are placed in Stage Right configuration are performed with automatic bar code readers and video cameras attached to an inventory pallet. This pallet is moved inside the magazine by either the shielded Stage Right forklift or an automated guided vehicle. As the pallet is moved, the bar code reader and video camera verify the presence of each pit container within the magazine and the integrity of both the container and the tamper-indicating device. Only the driver using the shielded forklift is required to be in the magazine during the inventory. The use of an automated guided vehicle is currently being implemented. No personnel are required in the magazine with the automated guided vehicle. No pit movement is required for the inventory. All other inventories of magazines not in Stage Right configuration (weapons, weapons components, etc.) are inventoried by hand.
Random pit evaluations are required to meet component reliability requirements. Less than 30 pits (approximately) are selected each year for these evaluation activities. The pallets containing the pits chosen for evaluation are removed from the magazinemagazine either manually or using Stage Right techniques and equipment. These pits are transferred to Zone 12 for evaluation activities.
The shielded cab on the Stage Right forklift protects the driver from ionizing radiation while inside storage magazines. Stage Right forklifts are equipped with a special boom that prevents penetration of plutonium containers during handling operations. This boom is equipped with a limit switch that stops the forklift if the boom accidentally touches a pit container. Stage Right forklifts are operated within guide rails that prevent movement of the forklift outside a clearly defined path. Zone 4 personnel involved in pit movements are required to wear lead aprons.
4.12.1.3 Radiological Exposures from Onsite Radioactive Material Shipments and Zone 4 West Nuclear Material Staging Activities
Radiological exposures incurred by workers in the Transportation and Staging Department during the performance of both transportation and staging activities for the years 1993 through 1995 are provided in Table 4.12.1.31. Onsite transfers of SNM within buildings and between bays and cells are performed by the production technicians or Production Stores personnel. Exposures related to these activities are considered as part of production operations, not transportation. The doses incurred by workers in the Waste Operations Department are also provided in Table 4.12.1.31. These doses were incurred in the performance of all activities involving radioactive waste, not just transportation.
4.12.1.4 Onsite Transfers of high explosive(s) (HE)High Explosive Material
Pantex Plant operations involve the onsite movement of high explosive(s) (HE)HE. These explosives include Department of Transportation (DOT) Hazard Class/Division 1.1, DOT Hazard Class/Division 1.3, and DOT Hazard Class/Division 1.4. DOT Hazard Class/Division 1.1 explosives include, but are not limited to, RDX, HMX, and TNT.
These explosives are used as the primary HE component in nuclear explosives. DOT Hazard Class/Division 1.3 explosives include TATB. This explosive is also used as a primary HE component in nuclear explosives. TATB is considered an insensitive high explosive, because it is extremely stable and resistant to heat, shock, and impact. DOT Hazard Class/Division 1.4 includes detonators, ignitors, timers, and switches.
HE is transferred at Pantex Plant Site to support assembly and disassembly operations. The HE is placed in an approved container prior to any transfer being performed. All transfers are conducted using Pantex Plant approved procedures. Routes for HE transport are restricted to paved roads. Vehicles used for the transport of HE must be equipped with a flashing amber light, which is operated at all times when explosives are being transported. The detonation of HE within an onsite trailer is considered an extremely unlikely event (10-4 to 10-6 per year) (Pantex 1994:3-71). In addition, the consequences of an HE detonation would not result in hazardous offsite consequences (Pantex 1993:3-15).
4.12.2 Impacts of Proposed Action
4.12.2.1 Impacts of Continued Operations
Under the Proposed Action, the following onsite transportation and staging activities will continue at Pantex Plant:
- Dismantlement activities with accompanying onsite hazardous material transfers (e.g., weapons, pits).
- Stockpile management activities with accompanying onsite hazardous material transfers (e.g., weapons, tritium reservoirs).
- Zone 4 staging of weapons, canned subassembly (CSA)CSAs, and adioisotopic Thermoelectric Generator (RTG)RTGs with accompanying inspection, inventory, and surveillance activities.
- Onsite transportation activities for other materials (e.g., wastes, chemicals).
- Storage of up to 20,000 pits with accompanying inspection, inventory, and surveillance activities at Zone 4, and pit transfers between Zone 12 and Zone 4.
- The transportation associated with the repackaging of pits from ALR8 containers into other DOT-criteria containers (i.e., onsite pit transfers of up to 20,000 pits between Zone 4 and Zone 12).
Nuclear explosives from both dismantlement and stockpile management activities would continue to be transported and handled within the Pantex Plant boundary. Transfers would be performed as described in sections 4.12.1 and 4.16.1 (Intersite Transportation of Nuclear and Hazardous Materials). No public exposure to radiation is expected from onsite, incident-free transport of nuclear explosives.
Pit components from both dismantlement and stockpile management activities would continue to be transported and handled within the Pantex Plant boundary. These transfers are described in sections 4.12.1 and 4.16.1. In addition to dismantlement and stockpile management activities, pit transfers would occur as part of the pit repackaging effort. The pit repackaging effort would require the transfer of pits in ALR8 containers from Zone 4 West storage magazines to Zone 12, where they would be repackaged into DOT-criteria containers. The DOT-criteria containers would be returned to Zone 4 West for interim storage. All container transfers would be performed using Stage Right techniques and equipment. Current schedules indicate an average repackage rate of approximately 1,000 pits per year starting in 1997. No public exposure to radiation is expected from onsite, incident-free transport of pits.
canned subassembly (CSA)CSAs from both dismantlement and stockpile management activities would continue to be transported and handled within the Pantex Plant boundary. No public exposure to radiation is expected from onsite, incident-free movements of CSAs.
Radioisotopic Thermoelectric Generator (RTG)RTGs from both dismantlement and stockpile management activities would continue to be transported and handled within the Pantex Plant boundary. The twin pack currently used for onsite transport and handling of RTGs is being phased out in favor of a newer mode of the currently approved DOT6M, Type B package for all onsite transfers. Onsite transfers of RTGs do not have the potential for significant environmental impacts because an RTG within a transfer container does not present an external radiological hazard and RTGs are constructed in such a way that an accidental release of plutonium is not reasonably foreseeable in the onsite transportation environment. RTGs are able to withstand an exposure of 1,000 ûC (1,832 ûF) for 1 hour or an impact of 571 kilometers (355 miles) per hour on a steel surface with no plutonium release (GE 1975).
Tritium reservoirs from both dismantlement and stockpile management activities would continue to be transported and handled within Pantex Plant boundary. No worker or public exposure to radiation occurs from onsite incident-free movements of tritium reservoirs.
Onsite transfers of depleted uranium (DU)depleted uranium (DU) would continue, but transfers of DU do not result in significant environmental impacts. DU does not present an external radiological hazard in the transportation environment. The radiological hazard of uranium depends upon its degree of enrichment. With increased enrichment, there is a corresponding increase in the radiological hazard from the uranium (DOE 1988).
DOE is using the safety analysis process as defined in DOE Order 5480.23 to identify and control threats to the safety of onsite shipments of radioactive material. Safety issues related to onsite transportation activities are currently evaluated in the Onsite Transportation Safety Risk Assessment (Pantex 1994). However, DOE is planning to issue a complete Safety Analysis Report for onsite transportation activities.
The bounding onsite transportation accident (low probability/high consequence), in terms of offsite consequences, would be an accident involving the detonation of high explosive(s) (HE)HE contained within weapons during transit. An HE detonation within a weapon would lead to the dispersal of plutonium and other radioactive material into the environment. (Weapons are designed so that in the event of an accidental HE detonation, there would be no significant nuclear reactions.) An accidental HE detonation is only possible for those weapon systems containing conventional HE. The insensitive HE contained in some weapon systems does not have the potential to accidentally detonate. It has been determined that the following scenarios may lead to an accidental HE detonation within an in-transit weapon: a long-lasting fire supplied with fuel by a crashed aircraft; or a mechanical impact to a weapon from a tornado, a wind-generated missile, a direct hit by a crashing aircraft, or a bullet striking thehigh explosive(s) (HE) HE.
Because of speed limits and protective handling gear, no onsite vehicle accident can create the impact conditions necessary for an HE detonation within a nuclear explosive. In addition, no onsite nuclear explosive movements are allowed in severe weather that may threaten the safety of the transport (e.g., tornado, severe wind). Nuclear explosives that are sensitive to bullet impacts (those containing conventional HE) are protected by a bullet resistant covering when not inside a hardened trailer or SST.
The likelihood of an aircraft crashing into a critical area at Pantex Plant is extremely remote. The probability of this event occurring is evaluated in section 4.15, Aircraft Accidents. The likelihood of an aircraft crashing into a critical area at Pantex Plant and affecting (by fire or direct hit) an intransit weapon is considered not reasonably foreseeable (frequency of occurrence is less than 10-6 per year) and at least several orders of magnitude less likely than an aircraft impact to a Pantex Plant facility (because of the limited target area of the trailer compared with facilities and the limited time that weapons are contained in a trailer).
In terms of risk (the product of probability and consequence), the potential environmental impacts from an airplane crash into a Zone 4 weapons magazine, as discussed in section 4.14 (Human Health), are much more significant than those associated with a crash into a hardened trailer. However, if this event were to occur, it would have the potential to cause environmental impacts. It is estimated that an HE detonation of numerous nuclear weapons within a hardened trailer would lead to a cumulative population dose of 4,820 person-rem with a corresponding public health risk of less than 2 x 10-7 excess cancer fatalities per year.
Other potential onsite transportation accidents are much more likely to occur but have less potential for environmental impacts. A characteristic high probability/low consequence accident involving radioactive material is a forklift puncture causing a release of plutonium from a pit container in the onsite transportation environment. This event is discussed in section 4.14, Human Health.
Zone 4 West Staging ActivitiesUnder the Proposed Action, as many as 20,000 pits could be stored in Zone 4. Approximately 60 storage magazines would be required to store that number of pits. This total includes 18 Modified Richmond magazines and 42 Steel Arch Construction magazines. PIT magazinemagazine activities would include inspections, inventory, surveillance pit removals, and repackaging pit removals. All of these activities would be performed using the Stage Right equipment and techniques.
In addition to the surveillance pit removals, DOE plans to sample a number of sealed storage containers from Zone 4 magazines. The purpose of this evaluation is to verify the integrity of the storage containers. It is expected that 20 to 22 containers would be removed from the magazines annually and taken to Zone 12 for evaluation. The containers selected for evaluation will be removed from a storage magazine and transported to Zone 12 using Stage Right equipment and techniques.
Other magazine activities that may occur within the timeframe evaluated in this EIS include the restacking of pits in a limited number of magazines to comply with design laboratory pit temperature limits and pit movements and instrumentation placements in a limited number of magazines to facilitate third-party verifications. In addition, to allow for operational flexibility, DOE may choose to store a small number of pits in a non-Stage Right configuration. All storage magazinemagazine operations will be performed in a manner that minimizes worker radiological exposure.
Radiological Impacts From Onsite Transfers of Radioactive Material and Zone 4 West Staging Activities
Because future stockpile management requirements cannot be accurately predicted, this EIS examines impacts associated with operations on 2,000, 1,000, and 500 weapons per year (and associated interzone transfers) in addition to the pit movements described above. Table 4.12.2.11 presents the estimated exposures to the 50 people (based on current operation levels) who are directly involved with transportation and staging operations. Workers who are not directly involved are not allowed in the vicinity of material transfer operations. These exposures were estimated using historical dosimetry information from the Transportation and Staging Department. No public exposure to radiation is expected from non-incident onsite material transfers and Zone 4 staging operations (Pantex 1996c; Battelle 1994).
Excess cancer fatality risks were calculated using a dose-to-risk conversion factor of 4 x 10-4 excess cancer fatalities per person-rem (NAP 1990). Assuming an operations on 2,000 weapons activity level and assuming that the same 50 people remain involved in material handling for the 10 years under evaluation in this EIS, there would be an additional 0.024 excess cancer fatalities in this group due to this exposure. The probability of cancer fatalities from all causes in the general population is estimated at approximately 20 percent, which implies that 10 of 50 workers who are not exposed to radioactivity from Pantex Plant will develop a fatal cancer anyway.
Assuming that a maximum exposed worker receives less than 300 millirem per year (which is consistent with historical doses [see Table 4.12.1.31]) over the timeframe evaluated in this EIS, the incremental increase in lifetime fatal cancer probability from the projected exposure period of 10 years is approximately 1.2 x 10-3 (1 chance in 833). The estimated probability of an average member of the public developing a fatal cancer from causes not related to this radiation exposure is 0.2 (1 chance in 5).
4.12.3 Impacts of No Action Alternative
Under the No Action Alternative, DOE will perform the following onsite transportation and staging activities at Pantex Plant:
- Dismantlement activities with accompanying onsite hazardous material transfers until the 12,000 pit storage limit is reached (e.g., weapons, pits).
- Stockpile management activities with accompanying onsite hazardous material transfers (e.g., weapons, tritium reservoirs).
- The transportation associated with the repackaging of pits from ALR8 containers into other DOT-criteria containers (i.e., onsite pit transfers of up to 12,000 pits between Zone 4 and Zone 12).
- Storage of 12,000 pits with accompanying inspection, inventory, and surveillance activities at Zone 4.
- Continuation of Zone 4 staging of weapons, CSAs, and Radioisotopic Thermoelectric Generator (RTG)RTGs with accompanying inspection, inventory, and surveillance activities.
- Continuation of other onsite transportation activities (e.g., waste, chemicals).
Table 4.12.31 presents the estimated exposures to the 50 people who are in transportation and staging activities. No public exposure to radiation occurs from non-incident onsite material transfers. All other impacts would be similar to those described for the Proposed Action. The difference between the Proposed Action (Table 4.12.2.11) and the No Action Alternative (Table 4.12.31) is due to a reduction in the number of pits being repackaged and the number of weapons being dismantled.bk3Safe Secure Tractor Trailer (SST)
4.12.4 Impacts of Pit Storage Relocation Alternative
IMPACTS FROM PIT STORAGE RELOCATION ALTERNATIVES- Because of the addition of a large number of SST Loading Operations, Transportation and Staging worker doses will increase for the Pit Storage Relocation Alternatives.
- At a 2,000 weapons level, the Transportation and Staging Department worker dose is estimated to be 61 person-rem for 10 years of operation.
- At a 2,000 weapons level, and with the relocation of 20,000 pits, the Transportation and Staging Department worker dose is estimated to be 344 person-rem for 10 years of operation.
4.12.4.1 Impacts of Relocating 20,000 Pits
Under this option, DOE would conduct the following onsite transportation and staging activities at Pantex Plant:
- Dismantlement activities with accompanying onsite hazardous material transfers (e.g., weapons, pits).
- Stockpile management activities with accompanying onsite hazardous material transfers (e.g., weapons, tritium reservoirs).
- Zone 4 staging of weapons, canned subassembly (CSA)CSAs, and RTGs with accompanying inspection, inventory, and surveillance activities.
- Onsite pit transfers (of up to 20,000 pits) between Zone 4 and bk2Zone 12Zone 12 associated with repackaging of pits from ALR8 containers into other DOT-criteria containers.
- Movement of pits to prepare for offsite shipment of up to 20,000 pits.
- Continuation of other onsite transportation activities (e.g., wastes, chemicals).
Onsite movements of nuclear explosives, non-pit nuclear explosive components (excluding pits), and other hazardous material would be identical to those occurring under the Proposed Action including the repackaging of pits. Movements of pits would differ from the Proposed Action in that pits stored in bk1Zone 4 would be shipped offsite. Impacts related to the offsite shipments of pits, including loading of pits into offsite shipment vehicles at Pantex Plant, are described below.
The loading and securing of pit containers within an Safe Secure Tractor Trailer (SST)SST will result in additional radiological exposureradiological exposures to onsite transportation workers. The over-the-road shipment of pits requires that the pit containers be restrained within the SST. Because of the complexity of the tiedown within a trailer, 10 to 15 minutes are required per container to perform the placement and tie-down operation. Transportation workers must be in proximity of the pit container during the placement and tie-down operation. Additionally, since an offsite pit shipment will contain more than one pit container, transportation workers will be in the proximity of numerous pit containers while operating within a trailer.
Because of the unavailability of historical dosimetry information specifically related to pit loading and unloading activities, conservative dose estimates have been made for this operation. Using estimates for time spent and position within a trailer during placement and tie-down operations and a dose rate of 1.5 millirem per hour at 1 meter from a pit package, the loading of pits into SSTs will result in an additional exposure of less than 27 person-rem per year (for 2,000 pits per year) or less than 270 person rem for 20,000 pits. Furthermore, the transfer of pits from magazinemagazines to SSTs would result in an additional 13 person-rem for the relocation of 20,000 pits. Further details of the assumptions used in these estimates are available in section F.7.
Onsite material movements for the 2,000 weapons level and the loading of 20,000 pits into SSTs is estimated to result in a 10-year cumulative dose of 344 person-rem (270 person-rem plus 13 person-rem for pit transfer loading activities plus 61 person-rem for normal operations) to transportation and staging workers. Using a dose-to-risk conversion factor of 4 x 10-4 excess cancer fatalities per person-rem and, assuming that the same 50 people remain involved in material handling and pit loading operations, there would be an additional 0.14 excess cancer fatalities in this group due to this exposure.
4.12.4.2 Impacts of Relocating 8,000 Pits
Under this option, DOE would relocate only 8,000 pits to other site(s). Pantex Plant would continue to store up to 12,000 PITs onsite. All other activities would remain as described under the Proposed Action including the repackaging of pits.
Onsite material movements for the 2,000 weapons level and the loading of 8,000 pits into SSTs is estimated to result in a 10-year cumulative dose of 174 person-rem (113 person-rem for pit transfer and loading activities plus 61 person-rem for normal operations) to transportation and staging workers. Using a dose-to-risk conversion factor of 4 x 10-4 excess cancer fatalities per person-rem and assuming that the same 50 people remain involved in material handling and pit loading operations, there would be an additional 0.07 excess cancer fatalities in this group due to this exposure.
4.12.5 Cumulative Impacts
The cumulative impacts presented here include impacts of the continued operations at Pantex Plant combined with impacts associated with activities described in the WM PEIS, SSM PEIS, and S&D PEIS. Since the Pantex Plant EIS Proposed Action and the SSM PEIS No Action Alternative represent a continuum of operations, the impacts associated with any new mission or facility that could be implemented at Pantex Plant are discussed in the context of that continuum. The impacts from the WM PEIS program are combined with those of the Pantex Plant EIS Proposed Action. The impacts from the S&D PEIS are combined with those of the SSM PEIS No Action Alternative. A detailed discussion of this methodology is presented in section 4.2.
Cumulative impacts of radiological exposure of workers and the public in the Pantex Plant vicinity are described in section 4.14, Human Health.
4.12.5.1 Impacts of Alternatives in the Waste Management Programmatic Environmental Impact Statement
Intrasite transportation is not addressed in detail in the WM PEIS, but is included in parts of the intersite transportation analysis. Future project-specific NEPA reviews would be expected to assess this issue, if one or more waste disposal facilities are to be constructed at Pantex Plant as a result of the WM PEIS.
4.12.5.2 Impacts of Alternatives in the Stockpile Stewardship and Management Programmatic Environmental Impact Statement
The SSM PEIS includes three alternatives that apply to Pantex Plant: No Action, Downsize Existing Capability, and Relocate Capability. Under the No Action Alternative, no downsizing or modification of facilities would occur. Due to the reduced workload expected in the future, impacts from intrasite transportation activities are expected to be less than current impacts. Under the downsizing alternative, the facilities would be consolidated. This could further reduce the amount of intrasite transportation impacts. Under the relocation alternative, intrasite transportation associated with assembly and disassembly operations and HE fabrication would cease.
4.12.5.3 Impacts of Alternatives in the Storage and Disposition of Weapons-Usable Fissile Materials Programmatic Environmental Impact Statement
As discussed in sections 1.4 and 1.7.3 of this volume, the final S&D PEIS will include an alternative under which plutonium pits from Rocky Flats Environmental Technology Site (RFETS) could be transferred to Pantex Plant for storage in Zone 4 as early as 1997. Impacts related to intrasite transportation and additional pit handling will be described in appendix Q of the S&D PEIS. Adding RFETS pits to pits from Pantex Plant dismantlement operations would not exceed the storage limit of 20,000 pits analyzed under the Proposed Action. Furthermore, RFETS pits have the same characteristics, as analyzed in the S&D PEIS, as pits currently or previously stored at Pantex Plant.
Placing RFETS pits in Zone 4 storage would, however, require repackaging RFETS pits from FL-type containers into AL-R8 containers in Zone 12 prior to placement into Stage Right configuration. Additionally, once repackaged, the pits would be transferred from Zone 12 to Zone 4. The total exposure to workers from both the transfer of pit containers and the repackaging of pits arriving from RFETS would result in less than 10-2 additional latent cancer fatalities for involved workers, as reported in appendix Q of the S&D PEIS. No exposure to the public is expected from these operations.
4.12.6 Potential Mitigation Measures
Onsite shipments of radioactive material have been performed for many years at Pantex Plant without a significant accident involving radioactive material. radiological exposureRadiological exposures incurred from future onsite transportation activities would continue to be controlled and minimized by Pantex Plant procedures, administrative controls, and an active As Low As Reasonably Achievable program that promotes work practices that minimize worker exposures. The Pantex Plant Radiological Control Manual, and ultimately, the Federal regulations for occupational radiation protection dictate the magnitude of radiological exposure to workers and safe radiological work practices (Pantex 1995d; 10 CFR 835).
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