5.2 Nevada Test Site
Under the Pit Storage Relocation Alternative (see section 3.1.3), pit storage operations at Pantex Plant would be transferred to another site. The Nevada Test Site (NTS) is one of the candidate sites for the storage of pits (Figure 5.2–1). The Device Assembly Facility (DAF), located in Area 6, and the P-Tunnel complex, located in Area 12, are the specific facilities being considered for interim pit storage at NTS. This section discusses each facility, the affected environment at NTS, and the potential impacts that would be associated with pit storage.
Each aspect of the affected environment at NTS has been assessed and the potential environmental impacts to each have been evaluated. Each environmental resource is discussed commensurate with the degree to which the resource could be impacted by or have an effect on interim pit storage at the candidate facilities.
Nevada Test Site. NTS is a government-owned, contractor-operated facility, currently managed by Bechtel Nevada. NTS encompasses approximately 3,500 square kilometers (1,350 square miles) of land area reserved to the jurisdiction of DOE. This land has been withdrawn from all forms of appropriation under public land laws. The four existing land withdrawals that comprise NTS are still being used for the purpose for which they were withdrawn. NTS is located in Nye County, Nevada, approximately 105 kilometers (65 miles) northwest of Las Vegas (Figure 5.2–1) (DOE 1996c:4-9). Due to its large size, the perimeter of NTS is not fenced; however, security patrols are used to control the site. Security and hazardous areas are fenced and some are protected with armed guards and electronic security measures (DOE 1995q:A-7).
Major activities at the site include maintaining the capability to conduct underground nuclear weapon tests, performing environmental restoration actions, supporting the Yucca Mountain high-level waste repository project and the DOE nuclear emergency response team activities, operating a DOE low-level waste disposal facility, and offsite monitoring of nuclear treaty compliance (DOE 1995q:A-8). Both DAF and P-Tunnel complex were designed and built to support the site's historical nuclear weapons mission.
Device Assembly Facility. DAF, located approximately 24 kilometers (15 miles) north of Mercury, is designed specifically to accommodate operations involving nuclear materials (PC 1995a). DAF is a 9,000-square meter (100,000-square foot) facility with state-of-the-art safeguards and security systems (Figure 5.2–2). Approximately 1,170 square meters (12,600 square feet) of this space is available for storing up to 8,000 pits. The facility structures are designed to withstand effects of site-specific natural phenomena, and a Perimeter Intrusion Detection and Alarm System already exists around the building. No construction involving new land disturbance would be required at this site.
As shown in Figure 5.2–2, DAF consists of a number of separate facilities (assembly cells, assembly bays and high bays, testing laboratories, and staging areas) and corridors under an earth cover. Since the original mission of DAF was nuclear explosive operations, the design of bays and cells in DAF is based on existing designs for bays and cells at Pantex Plant.
DAF has two shipping and receiving buildings for loading and unloading of pit containers. These buildings provide truck loading and unloading equipment, including a truckbed-height dock with a built-in leveler ramp and a staging area that is forklift, cart, and crane accessible.
Figure 5.2-1.--Location of Device Assembly Facility and P-Tunnel at the Nevada Test Site.
Figure 5.2-2--Simplified Layout of Device Assembly Facility at the Nevada Test Site.
Should DOE choose to store pits at DAF, a pit placement, retrieval, and inventory system would be implemented. It is expected that a Stage Right-like automated or shielded pit handling and inventory system would be developed.
P-Tunnel. P-Tunnel is one of several tunnels at Rainier Mesa (Area 12 of NTS) previously used by the Defense Nuclear Agency for conducting underground nuclear experiments (Figure 5.2–3). This tunnel has approximately 5 kilometers (3 miles) of usable tunnel length and approximately 240 meters (800 feet) of protective overburden. The tunnel is large enough to accommodate more than 20,000 pits. The tunnel portal area currently has several support structures, but there is no security fence to protect the tunnel area. A security system to protect the tunnel portal can be developed within the already disturbed area without disturbing new lands.
P-Tunnel would require minimal facility upgrades (primarily the installation of guide rails for a Stage Right forklift). No new pit placement, retrieval, and inventory system development effort would be required to accept a pit storage mission. The P-Tunnel alternative is well suited for the Stage Right equipment and techniques successfully implemented at Pantex Plant.
P-Tunnel is also being proposed for the long-term storage of weapons-usable fissile materials. The Storage and Disposition of Weapons-Usable Fissile Materials Programmatic EIS (DOE/EIS–0229) will address the long-term storage options including the P-Tunnel.
5.2.1 Environmental Resources Not Discussed in Detail
Each of the following environmental resources at NTS has been assessed. The
analyses show that the impacts to these resources from the potential storage of
pits at either DAF or P-Tunnel are small enough to warrant a limited discussion.
Therefore, these resources are discussed briefly below and will not be
addressed further in this section.
5.2.1.1 Facilities and Infrastructure
The infrastructure operations at NTS that could be impacted by or be expected to directly support pit storage operations include security, vehicle and building maintenance, utilities, administration, safety and health protection, and general support (e.g., cafeteria, general stores, etc.). Waste management and transportation support are discussed below and in sections 5.2.1.10 and 5.2.1.11, respectively. Direct impacts from the implementation of pit storage include a small increase in the NTS security force. Electrical usage due to interim pit storage (estimated to be 4,110 megawatthours per year) represents a 2.4 percent increase over the site's fiscal year 1993 usage of 168,000 megawatthours and 1.2 percent of the site's fiscal year 1993 system capacity of 350,000 megawatthours (DOE 1995k:A-8). Maintenance support and the indirect impacts resulting from pit storage worker requirements (e.g., water, wastewater treatment, and fuel), would increase minimally in comparison to the current and historical onsite infrastructure support levels and system capacities. Neither facility is currently being utilized at historical or design levels. P-Tunnel modifications would involve construction of a secure access control system at the tunnel portal. There would only be a insubstantial temporary impact to infrastructure services during this construction.
Figure 5.2-3--Layout of P-Tunnel at the Nevada Test Site.
5.2.1.2 Land Resources
No land disturbance is projected for DAF under the Pit Storage Relocation
Alternative, and only limited soil disturbance in an already disturbed area is
being considered for P-Tunnel (installation of a security system at the portal
to P-Tunnel). The Pit Storage Relocation Alternative does not include any new
land uses at NTS. Impacts to land use would not be expected.
5.2.1.3 Geology and Soils
The only aspects of geology and soils that could be affected by or have an
effect on the implementation of interim pit storage at NTS are soil disturbances
and the risks associated with earthquakes. The risks due to earthquakes were
assessed and found to be bounded by other accidents, as discussed in section
5.2.2.1. The only impact to soils would be from the construction of a secure
access control system at the P-Tunnel portal. This area has already been
repeatedly disturbed by the original mining of the tunnel and the subsequent
activities associated with nuclear testing. Upgrades to DAF that would involve
land disturbance are not anticipated; therefore, impacts to soils are not
anticipated.
5.2.1.4 Water Resources
Because of the nature of pit storage activities, operations at DAF or
P-Tunnel would not impact surface water or groundwater. The construction of a
secure access control system at the P-Tunnel portal is expected to minimally
impact surface water and groundwater because of the currently disturbed state of
the ground surface. No surface waters are withdrawn for use at NTS. Wastewater
is discharged to sewage lagoons, ponds, or septic tank/leach field systems and
not to natural surface waters. Wastewater would not have a measurable effect on
groundwater quality because of the combined effects of a deep water table (152
to 732 meters [500 to 2,400 feet] below land surface), low discharge volumes,
high evaporation rates, and a composition consistent with treated and sanitary
wastewater regulations. The water demands of pit storage operations are
attributed to personnel usage and are considered negligible in comparison to the
2,400 million liters (633 million gallons) used annually at NTS (DOE
1995k:4-116, 4-147).
5.2.1.5 Air Quality
NTS air quality is well within all applicable local, State, and Federal
ambient air quality standards except for particulate matter of aerodynamic
diameter less than 10 micrometers (PM10). The 24-hour PM10 standard is exceeded
due to moderate background concentrations of dust and contributions from
operations at NTS. The impacts to air quality from normal pit storage
operations would be due entirely to vehicle emissions (approximately 150
vehicles per day) and are considered negligible relative to the overall
vehicular emissions at NTS.
5.2.1.6 Acoustics
The major sources of noise at NTS include equipment, machines, blasting and
explosives testing, and military aircraft operations. At the NTS boundary, away
from most facilities, noise from most sources is barely distinguishable above
background sources. The only sources of noise that would be associated with pit
storage operations would be from transportation vehicles and air conditioning
and heating equipment for the occupied areas of the facility. These impacts
would be minimal and are not expected to be discernible offsite.
5.2.1.7 Biotic Resources
The threatened desert tortoise (Gopherus agassizii) is the only Federally
listed threatened or endangered species that permanently resides on NTS,
although the bald eagle (Haliaeetus leucocephalus) and American peregrine falcon
(Falco peregrinus anatum) may occur on an incidental basis (DOE 1995p). DAF is
in an area of infrequent desert tortoise activity, and P-Tunnel is outside the
range of the desert tortoise at NTS. Though the existing U.S. Fish and
Wildlife Service Biological Opinion for NTS requires a preactivity survey for
any project that would result in soil disturbance, no soil disturbance is
projected for interim storage of pits at DAF, where desert tortoise activity is
infrequent (DOE 1995n:10). The existing U.S. Fish and Wildlife Service
Biological Opinion requires all personnel at NTS to complete the DOE Nevada Area
Office Desert Tortoise Education Program to minimize the risk to desert
tortoises from construction, maintenance, and transportation activities (Letter
1992:7-8). No wetlands beyond those associated with isolated springs have been
identified at NTS (DOE 1993g:4-12, 4-27). As a result, impacts to biotic
resources would not be expected.
5.2.1.8 Cultural Resources
No historic or prehistoric sites have been found at P-Tunnel (DOE 1992d:1-4, 8). Nine sites, seven of which were single, isolated artifacts, were located at DAF. These sites were not recommended for eligibility to the National Register of Historic Places (DRI nd:1-3; DOE 1994s). The Pit Storage Relocation Alternative does not include any action that would disturb these sites. Therefore, no direct impacts to cultural or paleontological resources would be expected.
DOE has ongoing consultation with 13 Native American tribes and one
pan-tribal organization (the Owens Valley Board of Trustees) that have cultural
ties to NTS. Native American groups including the American Indian Writers
Subgroup of the Consolidated Group of Tribes and Organizations at NTS have
expressed concern regarding areas containing Traditional Cultural Properties
(DOE 1995k:4-123). The Pit Storage Relocation Alternative is not expected to
adversely affect these areas of concern. However, the Consolidated Group of
Tribes and Organizations would be consulted prior to initiation of any
activities.
5.2.1.9 Socioeconomic Resources
Approximately 150 additional personnel (including 120 security personnel)
would be required for interim storage of pits at NTS. This number represents
less than a 3 percent increase in the total NTS workforce. Most of these
workers can be locally hired; therefore, no significant site or regional
population and workforce increases are anticipated. According to the 1990
Census, 150 workers represent 0.03 percent of the employed workforce in the
socioeconomic Region of Influence, which includes the Las Vegas metropolitan
area (NV Cen 1993:Table 145). No socioeconomic impacts would be anticipated.
5.2.1.10 Waste Management
NTS currently manages mixed waste, low-level waste, hazardous waste, and
nonhazardous waste in accordance with a number of Federal and State regulations,
permits obtained under these regulations, and DOE orders. These requirements
are primarily under the authority of the Environmental Protection Agency, DOE,
and the State of Nevada Department of Environmental Protection's Bureau of Waste
Management (DOE 1995k:Chapter 5). NTS anticipates disposal of 14,100 cubic
meters (18,500 cubic yards) of mixed waste and 28,300 cubic meters (37,000 cubic
yards) of low-level waste annually (DOE 1993h:63). Pit storage operations would
generate less than 1 cubic meter (1.3 cubic yards) each of mixed, low-level, and
hazardous waste, which would not impact the current waste management at NTS.
5.2.1.11 Intrasite Transportation
Mercury Highway is the primary route into NTS from U.S. Highway 95 (Figure 5.2–1). Vehicular access to the DAF is via the Mercury Highway, which is a 7.8-meter (26-foot) wide paved road. DAF is approximately 1.5 kilometers (4,900 feet) west of the Mercury Highway and is served by a paved access road. The Mercury Highway is a controlled access road within the NTS boundaries and is not open to the public. P-Tunnel is located in Area 12 of NTS, north of the Area 12 camp. Vehicular access to P–Tunnel is via the Mercury Highway, Tippipah Highway, Rainier Mesa Road, and Road 12–01, as shown in Figure 5.2–1. The traffic on these roads is controlled by NTS personnel; no public traffic is allowed on these roads. Because a release of plutonium from an intersite pit shipment would require a severe accident (e.g., an accident with a fuel tanker or train [see section 4.16.4.2]), the controlled transportation environment within NTS does not pose a significant threat to pit shipments. Consequently, the contribution to overall transportation risk from onsite transportation is negligible. Radiological impacts of unloading pits at the two facilities are described in section 5.2.2.1, Human Health.
5.2.1.12 Aircraft Accidents
The airspace above NTS, designated as R4808, is a special-use airspace identified by Federal Aviation Administration regulations. This designation applies to all aircraft and is unlimited in height. Clearance to enter the restricted airspace above NTS must be obtained from DOE. Aircraft pilots desiring to fly through NTS airspace are required to contact the DOE Operations Coordination Center at NTS; information regarding the type of aircraft and nature of flight into the restricted airspace must be provided. DOE does authorize flights into the restricted airspace.
There are four airports and five landing strips in the vicinity of DAF and P-Tunnel. Las Vegas McCarran International Airport is the major commercial airfield in the State of Nevada. This airport, located approximately 122 kilometers (76 miles) southeast of NTS, is used by commercial (air carrier and air taxi), military, and general aviation aircraft. In 1994, McCarran International Airport had 488,347 aircraft operations (take-offs and landings). North Las Vegas Airport is located just north of McCarran International Airport and is used by commercial air taxi, military, and general aviation aircraft. In 1994, North Las Vegas Airport had 188,707 aircraft operations (take-offs and landings). Table 5.2.1.12–1 summarizes the total number of airfield operations at the McCarran International and North Las Vegas Airports (PC 1996j). Nellis Air Force Base, located 107 kilometers (67 miles) from NTS, is also north of McCarran International Airport and is only used by military aircraft.
The closest airfield to NTS, Indian Springs Auxiliary Field, approximately 48 kilometers (30 miles) southeast of DAF, has two runways used only by military aircraft. Beatty Airfield, approximately 67 kilometers (42 miles) west of DAF, has one runway used only by general aviation aircraft. There are five landing strips located on or near NTS; the most frequently used is the Desert Rock Airstrip, located in Area 22 southwest of Mercury. Desert Rock Airstrip has a single runway and is 30 kilometers (19 miles) south of DAF. Two single runway airstrips are located on NTS; one 6 kilometers (4 miles) north at Yucca Lake in Area 6, and the other 27 kilometers (17 miles) south in Area 22. Two single-runway airstrips are located west of NTS; one 62 kilometers (39 miles) west-northwest and the other 78 kilometers (49 miles) north-northwest.
Four of the landing strips and the four airfields are outside the probability density function boundary for the types of aircraft that use each of the facilities. The operations at the landing strip near Yucca Lake are infrequent and restricted to use by the public, and were therefore not included in the analysis. Only non-airport (in-flight) aircraft were therefore included in the analysis as required by the Draft DOE Standard (DOE 1996g). Further details on these nine facilities are contained in volume II, appendix E.
Penetration calculations for Manzano Weapons Storage Area (WSA) indicate aircraft cannot penetrate 9 meters (30 feet) of soil and rock. Since the proposed pit storage location inside of P-Tunnel is approximately 240 meters (800 feet) below the mesa, pits stored in P-Tunnel are immune from aircraft accidents (PC 1995b).
DAF was modeled conservatively as a single facility with a length of 201 meters (659 feet), a width of 76 meters (250 feet), and a height of 9 meters (30 feet) (PC 1994c). Using the Draft DOE Standard for determining the frequency of aircraft crashes, the frequency of hitting DAF was calculated as 1.5 x 10-6 for all types of aircraft (DOE 1996g). It should be noted that the frequency calculation represents a conservative upper bound. Since this frequency is greater than 10-7, in accordance with the Draft DOE Standard, further analysis was necessary. A local response structural analysis for the facility was performed according to the Draft DOE Standard with a wall thickness of 46 centimeters (18 inches) (DOE 1986b). This wall thickness was selected since it is the minimum thickness for the bays and cells where plutonium would be stored. An overburden of 1.5 meters (5 feet) was included for three sides of the facility.
The analysis was performed for the maximum penetrator missile
for each of the aircraft categories mentioned in section 4.15.2, except for
helicopters. The commercial air carrier, large military, and small military
aircraft categories were the only three aircraft missiles capable of penetrating
the facility from the side with no overburden; the frequency of releasing
material from DAF was 8.1 x 10-8. Since this frequency is less than 10-7, in
accordance with the Draft DOE Standard, no further analysis was required.
Further details of the frequency of hitting DAF and the frequency of releasing
material are contained in volume II, appendix E.
5.2.2 Resources Discussed in Detail
5.2.2.1 Human Health
The basic approach used in assessing human health concerns is to first identify the affected environments and establish a baseline that represents the risk from current operations. Changes in this baseline risk resulting from the Pit Storage Relocation Alternative are then examined. Impacts from both normal operations and potential accidents are estimated.
Assessing the human health risk impact from potential accidents resulting from the relocation of pits to NTS and storing them in either DAF or P-Tunnel involves a risk screening process. The first step in this process is to identify a broad spectrum of potential accident scenarios. The second step in the process uses screening techniques to identify the specific scenarios that dominate risk (i.e., scenarios that contribute an appreciable fraction of the total risk), where risk is the product of frequency and consequence. Rigorous consequence evaluations are only performed for the identified risk-dominant scenarios.
Two types of accident consequences are examined:
- Worker and public exposure.
- The probability of the accident causing fatal cancer in a worker or the public.
If DOE chooses to relocate pits to NTS, two aspects of this relocation contribute to a potential for environmental impacts. They are the impacts associated with:
- Transferring pits from the transporter to their storage location inside the facility.
- Storage itself (i.e., potential impacts resulting from having the pits reside inside the facility).
Each time pits are transferred from the transporter to their storage location inside the facility, there is a small probability that an accidental release could occur due to a handling accident. In addition, the transfer of pits from the transporter to their storage location would result in radiological exposures to involved workers.
Affected EnvironmentThe release of radioactivity and toxic chemicals to the environment from a DOE facility is an important issue for onsite workers and the public. Since the human environment contains many sources of radioactivity and toxic chemicals, it is essential to understand the sources of these substances and how effectively they are controlled.
Table 5.2.2.1–1 summarizes the major sources of radiation exposure in the vicinity of NTS. The average annual probability of developing a fatal cancer for a resident of Nevada is 1.4 x 10-3. Using a nominal fatal cancer risk factor of 5 x 10-4 cancer fatalities per person rem and the environmental radioactivity data for NTS in Table 5.2.2.1–1, it is calculated that fatal cancers attributable to environmental radioactivity released from NTS constitute a negligible fraction of the average yearly fatal cancer probability in the vicinity of NTS (DOE 1994t:4-20).
Figures 5.2.2.1–1 and 5.2.2.1–2 depict the offsite population within an 80-kilometer (50-mile) radius of DAF and P-Tunnel, respectively. Wind speeds and directions in the NTS vicinity are presented in Figure 5.2.2.1–3. Winds are predominately from the southwest during the summer and from the northeast during the winter.
Impacts of Facility UpgradesThere is no significant impact on human health associated with NTS facility upgrades. The only upgrade required is to modify P-Tunnel and DAF to accept Stage Right transfer and storage equipment. The facility impact involves modifying floor space to accept Stage Right guide rails and fastening Stage Right attachment fixtures to storage facility walls. These are standard industrial operations that do not expose workers to any special hazards (e.g., radionuclides, toxic chemicals, or high explosives).
Table 5.2.2.1-1.--Major Sources of Radiation Exposure in the Vicinity of the Nevada Test Site (.pdf)
Impacts of Storing 20,000 PitsHuman health impacts from pit storage activities could potentially result from normal operations and potential accident scenarios. Normal operations would impact only onsite workers. Normal operational impacts result from the unloading of pits from Safe Secure Tractor Trailers (SSTs) at the P-Tunnel access area. Unloading operations would result in radiological exposure to cargo handlers. Based on conservative calculations made for the handling of pits at Pantex Plant, worker doses from unloading 2,000 pits per year are estimated to be 27 person-rem per year or 270 person-rem for unloading 20,000 pits (the maximum number of pits which may be stored at P-Tunnel). Once removed from the SSTs, pits would be transferred into P-Tunnel for storage. Pit transfers within P-Tunnel would result in radiological exposures to onsite workers handling the pits; doses of less than 2 person-rem per year for handling 2,000 pits and about 13 person-rem for the placement of 20,000 pits.
The combined worker dose from unloading and storage of 20,000 pits at P-Tunnel would be 283 person-rem distributed over the 30 people directly involved in material handling. Assuming that the same 30 people continue to handle 20,000 pits over a period of 10 years and using a dose-to-risk conversion factor of 4 x 10-4 latent cancer fatality (LCF) per person-rem, there would be an additional 0.11 LCF experienced by this group due to radiological exposure from pit handling.
The probability of LCFs from all causes in the general population is estimated at 20 percent, which implies that 6 of 30 workers would develop a fatal cancer from all other causes. With an additional 0.11 LCF from pit handling, the total risk of latent fatal cancers among workers at P-Tunnel would increase by 1.8 percent.
Some operational accidents could result in impacts to both onsite workers and the offsite general population. Radiological exposures and the resultant risk of LCFs have been calculated.
Figure 5.2.2.1-1--Population Within 80 kilometers (50 miles) of Device Assembly Facility.
Figure 5.2.2.1-2--Population Within 80 kilometers (50 miles) of P-Tunnel.
Figure 5.2.2.1-3--Wind Speed and Direction at the Nevada Test Site.
The probability of an onsite worker contracting a fatal cancer from radiological exposures from pit storage activities was calculated using a fatal cancer risk factor of 4 x 10-4 LCF per person-rem, and the cumulative worker dose was estimated from previous historical doses resulting from similar operations (ICRP 1991).
The risk screening methodology indicates that the radiological health risk from accidents associated with the storage of 20,000 pits in P-Tunnel is dominated by handling accidents that could occur when the pits are being transferred from the transporter. A standard tine forklift is likely to be used to remove pit containers from an SST. Using DOE's methodology, the probability of a standard tine forklift causing a puncture during a single handling operation is in the extremely unlikely range (i.e., 10-4 to 10-6) (DOE 1992h). For handling 2,000 pits annually, the accident frequency is approximately 10-3 per year. This relatively low accident frequency results from the robust construction of AT–400A shipping containers.
Pit container inventories at NTS are expected to be performed using either shielded or automated techniques and equipment. Consequently, these normal operations are not expected to result in any significant radiological exposure to workers.
Other storage activities that may occur within the timeframe evaluated in this EIS include:
- Restacking a limited number of pits to comply with design laboratory temperature goals.
- A limited number of pit movements and/or instrumentation placements to facilitate third-party inspections.
Impacts of these routine activities are also considered to be negligible.
Earthquakes offer the greatest threat from natural phenomena (see appendix D). Available seismology studies show that active faults such as the Mine Mountain Fault, the Carpetbag Fault, Yucca Flat Fault, and the Cane Spring Fault in the NTS vicinity are capable of generating earthquakes of up to 0.85 g (Raytheon 1995:2-36). NTS has a natural background seismicity (Raytheon 1995:2-33). The Cane Springs fault, located 5 to 8 kilometers (3 to 5 miles) south-southeast of DAF, has been identified as the most significant feature from the standpoint of seismic risk. However, a large proportion of seismic events occurring near NTS may have been aftershocks from past nuclear explosions.
The proposed pit storage area in P-Tunnel is only a few hundred feet away from the site of some past nuclear explosions. Since the tunnel has survived these explosions without noticeable degradation, it is not reasonably foreseeable that the proposed pit storage area would be damaged by an earthquake. However, if the tunnel collapses, the impact forces could breach some certified shipping containers. The collapse would also seal the containers inside the tunnel, resulting in no significant short-term radionuclide releases to the exterior environment. Thus, the consequences to the public and workers are considered negligible. Some mitigation of a tunnel collapse would be needed after a major seismic event. A separate assessment of the risk associated with the mitigation would be necessary in order to address the specific magnitude of the collapse and the applicable mitigation technology.
Impacts of Storing 8,000 PitsStorage of 8,000 pits could be accomplished at either P-Tunnel or DAF. The risks associated with storing 8,000 pits in P-Tunnel are similar to but less than those of the 20,000-pit storage alternative. The total worker doses from unloading and pit transfer operations would be below 113 person-rem over 4 years. This exposure would result in an additional 0.04 LCF in this group. With an additional 0.04 LCF from pit handling, the total risk of LCFs among workers at NTS would increase by 0.7 percent.
Risk screening methodology also indicates that the risk from storage of 8,000 pits in DAF is dominated by forklift handling accidents. Note that the risk screening methodology evaluated all potential threats to pit container integrity, such as fire, aircraft crash, earthquake, flood, and other internal and external events.
Although DAF is more vulnerable to external events and natural phenomena than P-Tunnel, the contribution from these events to overall risk remains negligible as discussed in appendix D. Compared to the risk from a forklift accident during pit handling, the risk from aircraft accidents and earthquakes at DAF is low. To a significant extent, the low seismic risk at DAF is attributable to the robust construction of the facility (Raytheon 1995:5-7). Aircraft accidents are negligible risk contributors because of the extremely low probability of an impact.
It is estimated that a forklift puncture of a pit container would release 9.2 x 10-5 curies of plutonium. This is a conservative estimate of the respirable, airborne release caused by a puncture of one shipping container (DOE 1992f:7-39).
Given such a release, an involved worker (the forklift driver) would receive a dose of 6.6 rem, corresponding to an incremental increase in lifetime fatal cancer probability of 2.6 x 10-3. In addition, a non-involved worker 100 meters (328 feet) downwind along the center line of the plutonium dispersion plume would received a 6.3 x 10-2 rem exposure, corresponding to an incremental increase in lifetime fatal cancer probability of 2.5 x 10-5. The maximally exposed member of the public would receive a 3.9 x 10-5 rem exposure, corresponding to an incremental increase in lifetime fatal cancer probability of 2 x 10-8. The lifetime fatal cancer probability for an average individual from all other causes is approximately 0.2 (20 percent).
This event would result in an exposure to the public of 3.3 x 10-5
person-rem. Considering the likelihood and consequence of this event, on the
average, a member of the public will have an increased annual risk of developing
a fatal cancer from this potential accident of 1.1 x 10-15 fatal
cancers per year. The annual fatal cancer risk to a person in Nevada from all
other causes is 1.4 x 10-3 fatal cancers per year.
5.2.2.2 Environmental Justice
Affected EnvironmentIn order to identify the target populations covered by Executive Order 12898, 80-kilometer (50-mile) radius circles centered on DAF and P-Tunnel were overlaid on 1990 Census tract maps (UN 1995). The communities that lie within these 80-kilometer (50-mile) circles, hereafter called the DAF and P-Tunnel Regions of Influence (ROIs), are shown in Figure 5.2.2.2–1.
Population. According to the 1990 Census, there were 11,741 persons within the DAF ROI. White persons comprised nearly 84 percent of the population, Hispanics were the second largest group with slightly more than 7 percent, and Blacks accounted for slightly less than 7 percent of the total population in the ROIs. American Indians, Asians, Pacific Islanders, and other racial groups totaled less than 3 percent of the total population within 80 kilometers (50 miles) of the DAF ROI in 1990 (UN 1995).
In 1990, nearly 96 percent of the population in the DAF ROI lived in the communities of Beatty, Pahrump, Mercury, and Indian Springs; the remaining population lived in the Amargosa Valley area (NV Cen 1992:Table 1; UN 1995). Thus, the entire population within the DAF ROI lived west, south, and southeast of the DAF site.
Figure 5.2.2.2-1--The Device Assembly Facility and P-Tunnel Regions of Influence in Nevada.
According to the 1990 Census, there were 4,386 persons within the P-Tunnel ROI. White persons comprised 84 percent of the population, Hispanics were the second largest group with 8 percent, and Blacks accounted for 5 percent of the total population in the circle. American Indians, Asians, Pacific Islanders, and other racial groups totaled less than 3 percent of the total population within the P-Tunnel ROI in 1990 (UN 1995).
In 1990, nearly 87 percent of the population in the P-Tunnel ROI lived in the communities of Beatty, Mercury and Indian Springs; the remaining population lived in the Amargosa Valley area (NV Cen 1992:Table 1; UN 1995). Thus, the entire population within the P-Tunnel ROI lived south, southwest, and southeast of P-Tunnel.
Minority Population. Figure 5.2.2.2–2 shows the 1990 Census block groups within the DAF ROI. The block groups are shaded if 25 percent or more of their populations were minority persons in 1990 and/or if 25 percent or more of their populations were below the poverty level based on their incomes in 1989. The 25 percent threshold levels for minority or low-income persons are based on the working definitions contained in the notice of the EPA's Office of Environmental Justice (59 FR 192). Three block groups within the DAF ROI have populations which were at least 25 percent minority or non-White in 1990. These concentrations of minority persons are found primarily in the communities of Indian Springs, Cactus Springs, and Mercury. In the P-Tunnel ROI, the distribution of minority population is similar to that of the DAF ROI (Figure 5.2.2.2–3).
Low-Income Population. Three block groups within the DAF ROI have populations in which at least 25 percent of persons were below the poverty level based on their incomes in 1989. These concentrations of low-income persons are found primarily at the eastern edge of Pahrump, in the western portion of Amargosa Valley, and in the Death Valley Junction area in California. In the P-Tunnel ROI, only one block group (the western portion of the Amargosa Valley area) has a population in which at least 25 percent of persons were below the poverty level.
Impacts of Storing 20,000 PitsBecause the interim storage of pits at the P-Tunnel would not require any major construction and because all facility modifications would take place inside existing facilities, impacts to the natural environment would be minimal. Under normal operating conditions, there would be minor increases in air pollutants associated with vehicles used during pit storage activities. Also, a minor increase in PM10 concentrations would be expected. These increases are associated with the operation of forklifts which are used to move the pits from the unloading area to the storage area.
These impacts are not likely to affect the surrounding population. Radiological releases from normal pit storage operations would have no measurable effect on an individual occupying a position near the Nevada Test Site (NTS)Nevada Test Site (NTS)NTS boundary for an entire year. Levels at the site boundary would be indistinguishable from natural background radiation. No adverse health effects would be expected among the general public, including minority and low-income populations, as a result of normal storage operations.
An abnormal event, such as accidental puncture of a pit storage container by a forklift, has the potential of exposing the general public to radiation. The analysis in the section 5.2.2.1, Human Health, indicates that the risk to the public from such an accident would be negligible. With no measurable impacts on the general population, the minority and low-income populations would not be disproportionately impacted.
Impacts of Storing 8,000 PitsThe human health impact of storing 8,000 pits in P-TunnelP-TunnelP-Tunnel would be lower than those identified for the storage of 20,000 pits. No significant adverse impacts are expected, and minority and low-income populations would not be disproportionately impacted.
The human health impacts of storing 8,000 pitpitpits in DAF would be negligible to the general public in the Device Assembly Facility (DAF)Device Assembly Facility (DAF)DAF ROI. Since impacts to the general public are expected to be negligible, minority populationminority populationminority and low-income populationlow-income populationlow-income populations would not be disproportionately impacted.
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