ML20217H494
| ML20217H494 | |
| Person / Time | |
|---|---|
| Site: | University of California-Davis |
| Issue date: | 03/30/1998 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML20217H482 | List: |
| References | |
| NUDOCS 9804030368 | |
| Download: ML20217H494 (7) | |
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9 . . . . . ,o UNITED STATES NUCLEAR REGULATORY COMMISSION ENVIRONMENTAL ASSESSMENT AND FINDING OF NO SIGNIFICANT ENVIRONMENTAL IMPACT REGARDING PROPOSED ISSUANCE OF FACILITY OPERATING LICENSE NO. R-130 DEPARTMENT OF THE AIR FORCE AT MCCLELLAN AIR FORCE BASE MCCLELLAN AIR FORCE BASE TRIGA REACTOR DOCKET NO. 50-607 The U.S. Nuclear Regulatory Commission (the Commission) is considering issuance of Facility Operating License No. R-130 for a term of 20 years for the Department of the Air Force at McClellan Air Force Base (AFB) (the applicant) 2.3-megawatt thermal (MW(t))
TRIGA reactor located at the McClellan Nuclear Radiation Center (MNRC), McClellan AFB, California.
ENVIRONMENTAL ASSESSMENT ;
Description of the Proposed Action This environmental assessment is written in connection with the proposed issuance of Facility Operating License No. R 130 for the MNRC TRIGA research reactor at McClellan AFB, California, in response to an application from the applicant dated October 23,1996, as supplemented. The proposed action would authorize operation of the MNRC reactor at a power level of 2.3 MW(t) for a period of 20 years. The MNRC has been in operation since mid-1991 under the authority of the Department of the Air Force under Section 91b of the Atomic Energy Act. The applicant has sought NRC licensing of the reactor because of the planned closure of McClellan AFB.
Need for the Proposed Action The proposed action will authorize continued operation of the MNRC to allow the applicant to perform its mission of neutron radiography, irradiation services, research and development, and teaching.
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Alternatives to the Proposed Action There are two principal alternatives to the proposed action. One alternative (the proposed
' alternative) would be to issue an operating license under the provisions of 10 CFR Part 50 for operation of a class,104(c) facility. The other alternative (the no-action alternative) would be to deny the application for an operating license, which would result in continued operation of the MNRC under the auspices of the Department of the Air Force. To take this action would not be responsive to the applicant and would have an environmental impact
. similar to the proposed alternative.
Site Description The MNRC is currently in operation at the McClellan AFB located approximately 13 km (8 mi) from downtown Sacramento, California, in the Central Valley between the coast range and the Sierra Nevada, about 145 km (90 mi) northeast of San Francisco, California. The
~ area is situated on the alluvial plains of the Sacramento River and its tributaries in a
- relatively flat area with an elevation of 15 - 23 m (50 - 75 ft) above mean sea level.
Approximately 700,000 people, including the city of Sacramento with a population of approximately 580,000, reside within 16 km (10 mi) of the MNRC. A detailed site description can be found in the MNRC Safety Analysis Report.
Facility Description
- The Reactor.
The MNRC reactor is a light water moderated and cooled TRIGA reactor, using low-enriched (less than 20 percent U 235) uranium fuel. Since mid-1991, the MNRC has been operated by McClellan AFB.for the U.S. Air Force. Although the licensed power level of the reactor is 2.3 MW(t), the applicant proposes in the technical specifications to operate the reactor at a nominal, maximum steady-state power level of 2.0 MW(t). The licensed power level limit of 2.3 MW(t) will be limiting when testing the reactor power level scram. The reactor has pulsing capability, with a maximum reactivity step addition of 1.75$ proposed by the applicant.
.The MNRC provides a broad range of radiographic and irradiation services for both military and non-military purposes. Nondestructive inspection of aircraft components, the primary function of the facility, is accomplished in four bays, each with its own beam of neutrons T for radiography purposes. All four bays are capable of using radiography film techniques, but Bays 1,2,' and 3 will normally.use electronic imaging devices. In addition to the radiography bays, the MNRC reactor core and associated experimental facilities are used to
. conduct a variety of irradiation services, including silicon' doping, production of both medical and industrial isotopes, and neutron activation analysis. Reactor usage has
- increased with time. The facility is currently operated 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a day,5 days a week.
The TRIGA reactor is located in a cylindrical aluminum walled tank, and the core is positioned approximately 0.6 m (2 ft) below grade. The reactor tank is surrounded by a
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,3 3-monolithic block of reinforced concrete. Below ground level, the concrete is approximately
- 3.4 m (11 ft) thick.- Above ground level, the concrete walls vary in thickness from 3 ,
approximately 3 m to'1 m (10 ft to 3% ft), with the small dime'nsion at the tank top. The 'I tank is supported by a concrete pad approximately 2.9 m (9% ft) thick.
The basic purpose of the massive concrete structures is to provide biological shielding for personnel working in and around the MNRC. However, the massiveness of these
. structures provide excellent protection for the reactor against natural phenomena, e Heat Dissipation System j
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' Heat generated by fission in the reactor fuel is removed from the primary cooling system by circulating pool water through a plate-type heat exchanger and transferring heat to the -
. secondary coolant. ' A mechanical draft cooling tower located outdoors removes heat
- absorbed by the secondary coolant through an evaporative process. Secondary system delta T during normal operation at 2 MW is 8 *C (15 'F). Evaporative water loss at full-power operation is estimated to be 51 Ipm (13.5 gpm). Secondary system blowdown to the industrial waste system limits the concentration of dissolved solids in the cooling tower i basin and is estimated to be approximately 49 Ipm (12 gpm). Makeup. water to offset evaporative loss and blowdown is provided by the McClellan AFB water' supply. The heat exhausted from the facility has averaged approximately 2500 MW-hours per year over the past 3 years, although this figure willincrease with the current 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a-day,5-day a-week usage, e Chemical Usage Approximately 2300 liters (600 gal) of a mixture of sodium hydroxide and phosphoric acid
- are used each year in the secondary cooling system for the prevention of hard scales (plated-out silicates). Approximately 400 liters (100 gal) of glutaraldehyde (brand name BioMax 15) are used each year in the secondary cooling system as a biocide. ,
Approximately 25 liters (7 gal) of buffer are used as reagents annually and approximately 30 liters (8 gal) of acetone and isopropyl alcohol are used for cleaning.
g . Radioactive Waste Management Radioactive waste generated from the operation of the MNRC is either monitored and released or packaged and transferred for offsite disposal. Examples of solid waste include
~ absorbent paper, plastic gloves, spent samples, contaminated laboratory apparatus, spent standards,~and clean-up resins from the domineralizer. Liquid waste typically consists of spent standards, diluents, and liquid from rinsing ~ of. contaminated objects during
' decontamination. Potential airborne waste includes nitrogen-16 (N 16), argon-41 (Ar-41),
and neutron-activated dust particles.-
Solid rs'dioactive waste is consolidated and compacted to reduce volume before it is 2
shipped either in 55-gallon drums or B-25 containers approved by the Department of
! Transportation for offsite disposal in a licensed burial facility.
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The volume of dry active waste produced by'the facility over the past five years is
' approximately 0.6 cubic meter per year (one 55-gallon drum and six resin bottles per year).
Solid waste shipment volumes very from year to year, from a low of 0 in 1995 and 1996, to'10.3 cubic meters in 1994 (when the majority of the waste was from disposal of.the old National Institute of Standards and Technology linear accelerator that was co-located with i the MNRC TRIGA).'
Radioactive liquid waste is generated only in very smalf, low-level quantitles and is recycled, evaporated, or solidified such that no radioactive liquid waste is released to the environment. It is MNRC policy not to release liquid effluents as waste or effluent.
Because normal MNRC operations create only small volumes of diquid that contain radioactive materials, it has been possible to convert the liquids to a solid form. The reactor coolant is the only significant source of radioactive liquid, and it is con.tained to the j
maximum extent possible. There are no routine releases of this liquid and, thus, no significant volumes of liquid that require management as liquid waste. Certain maintenance
. operations result in draining small amounts of primary coolant from the primary system, but this liquid is easily collected at the point of origin and converted into a solid waste form.
Other liquid radioactive waste sources, such as laboratory wastes, decontamination solutions, and liquid spills, have been very rare and easily within the capability of the health physics staff to convert to a solid. These practices are expected to continue, i
' The principal radioactive gaseous wastes consist of small quantities of nitrogen (N 16) and of argon (Ar 41) released through the effluent emission stack and mixed with ambient air.
The maximum exposure because of these isotopes for MNRC personnelis administratively controlled to be as low as reasonably achievable (ALARA) and well below the 5000-mrem /yr 4 limit in 10 CFR Part 20. For individuals immediately outside the controlled MNRC ]
operations area, the exposure rate is less than 1.4-mrem /yr, most of which is due to Ar-41 (the N-16 component is negligible). The amount of activated dust particles is negligible, and ;
its release to the environrnent would be controlled by the MNRC ventilation system. These exposures are significantly below the limits in 10 CFR Part 20 (including the new Clean Air Act constraint rule in 10 CFR 20.1101(d) of 10 mrem /yr) and are negligible when compared to the approximately 300-mrem /yr exposure received by the general public in the United States as a result of natural sources.
Releases of routine gaseous effluents are monitored and controlled and can, for all practical
_ purposes, be limited to Ar-41, which !s generated by neutron activation of Ar-40 in air. The Ar-41 is released thorough the effluent emission stack and is kept ALARA through reducing air release around the reactor tank to low levels. Technical specifications restrict the release rate of Ar-41 to the limits in 10 CFR Part 20. The highest release rate measured over the last 5 years at the MNRC was 3.8 microcuries per second, as compared to the technical specification limit which is equivalent to 115 microcuries per second.
Other Waste Management Chemical and sanitary waste systems servicing the MNRC are similar to those existing at other similar laboratories 'and buildings. l l
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i EnvironmentalImpacts of Continued Operation
- Heat Dissipation Release of thermal' effluents from the MNRC will not have a significant effect on the
. environment.' This small amount of waste heat (approximately 12,000 MW hours per year
. at 24-hour-a-day,- 5-day-a week operation) will be released to the atmosphere by means of the cooling tower. Neither extensive drift nor fog is expected to occur at this heat
- dissipation rate. The small amount of waste heat released to the sewers by way of the cooling tower blowdown will not raise the average water temperature in the environment.
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- Chemical Usage
~ Chemicals used at the MNRC are not discharged to and will not have a significant effect on the environment. The sodium hydroxide and phosphoric acid mixture used as a scale inhibitor and the glutaraldehyde used as a blocide are all confined to the secondary cooling system, except for that contained in the approximately 49-lpm (12-gpm) blowdown to the industrial waste system. The buffer solutions used are discharged to the industrial waste system after use. The acetone and isopropyl alcohol used for cleaning are either lost due to evaporation or absorbed by wipes and rags and disposed of in solid waste.
Radiological Impacts To determine the impact of effluent releases, the MNRC conducts an environmental monitoring program consisting of surveys of radiation fields and surveys for contamination.
Thirty (30) thermoluminescence dosimeters (TLDs) are placed at locations outside the perimeter of the reactor facility and are changed every 3 months. Since 1990, twenty one (21) of the thirty (30) TLDs located outside the perimeter have been placed in locations that meteorological conditions indicate will be the most likely to receive the maximum dose from Ar-41. In addition, TLDs are placed in various locations inside the MNRC, and the
' MNRC health physics staff conducts weekly surveys in accessible radiation areas and high-radiation areas, and in all other occupied areas of the MNRC. All of this monitoring confirms that individuals continualY working or residing near the reactor were highly unlikely to have received a total effective dose equivalent more than a small fraction of the
-10 CFR Part 20 limits. The environmental monitoring program is expected to continue
. indefinitely and will assist the applicant in ensuring that no member of the public receives an annual dose in excess of 10 CFR Part 20 limits (including the new Clean Air Act
> - constraint rule in 10 CFR 20.1101(d) of 10 mrem /yr). If such limits are approached, the applicant will take steps to analyze, control, and further limit the release of radioactivity and to ensure compliance with regulatory limits.
- Other Waste Management
- On the basis of the applicant's description of waste management practices, no release of
. potentially harmful chemical substances is expected to occur during normal operation.
Small amounts of nonradioactive chemicals or water with a high solid content may be 4
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released f'om r the facility.to the industrial waste system during periodic blowdown of the .
cooling tower or as a result of laboratory experiments. . Other potential effects of the
- MNRC's continued operation, such as noise or those that could adversely affect esthetics or the local flora and fauna, are expected to be minimal.
. Occupational Radiation Exposure Radiation exposures at the MNRC are very low. . Annual radiation exposures are typically
'below 50 mrem. In 1995, the collective dose for MNRC personnel was 2.9 person-rem, -
with the highest individual dose being 410 mrem. These individual doses are well below the limits set by regulatory requirements.
Environmental Effects of Accidents The staff reviewed the MNRC accident analysis presented in the applicant's safety analysis
. report as part of its safety evaluation and has concluded that there is reasonable assurance that such accidents will not release a significant quantity of fission products from the fuel cladding and, therefore, will not cause significant radiological hazard to the environment or the public.
This conclusion is based on the following information:
- 1. The maximum reactivity for any single experiment (and the absolute total reactivity worth of in tank experiments) allowed under the technical specifications is insufficient to support a reactor transient generating enough energy to cause overheating of the fuel or loss of integrity of the cladding.
2.' At a thermal power level of 2300 kilowatts, fuel failure could possibly occur in the unlikely event of a loss-of-coolant accident that uncovers the reactor core. The l licensee has installed an operator-actuated emergency core cooling system that can provide sufficient cooling to the reactor core to prevent fuel failure.
3.-- . The hypothetical loss of integrity of the cladding of one fuel element in air will not lead to radiation exposures for MNRC staff or in the unrestricted environment that exceed the guideline values of 10 CFR Part 20.
The NRC safety evaluation report associated with this action and the applicant's safety
' analysis report give a more detailed description of the MNRC accident analysis.
Long-Term Effects of Continued Facility Operation The long term effects of non-power reactor. facilities are considered to be beneficial as a
< result of their contribution to commerce, scientific knowledge,'and training. Because of the
- relatively small amount of capital resources involved and the small impact on the l
environment, very little irreversible or irretrievable commitment is associated with licensing i of the MNRC facility.
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7 ADencies and Persons Consulted The staff obtained the technical assistance of the Idaho National Engineering and Environmental Laboratory to perform the safety evaluation of licensing the MNRC TRIGA.
research reactor. This environmental assessment and finding of no significant impact was
. prepared by J. H. Wilson of the NRC staff. The staff consulted with the California official regarding the environmentalimpact of the proposed action, and the State official had no comments.
. Conclusion and Basis for No Significant impact Finding On the basis of the foregoing considerations, the staff has concluded that there will be no l significant environmentalimpact attributable to this proposed license issuance. Having reached this conclusion, the staff has further concluded that no environmental impact statement for the proposed action need be prepared and that a finding of no significant impact is appropriate.
For further details with respect to this action, see the applicant's request for an operating license dated October 23,1996, as supplemented on June 16, September 5, October 7
' and 9, and December 17,1997. These documents are available for public inspection at the NRC Public Document Room, the Gelman Building,2120 L Street, NW, Washington, D.C.
'20003.
Dated: March 30, 1998
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