ML15112B121
| ML15112B121 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 09/29/1983 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML15112B119 | List: |
| References | |
| NUDOCS 8310110575 | |
| Download: ML15112B121 (10) | |
Text
oUNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 ENVIRONMENTAL IMPACT APPRAISAL BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 123 TO FACILITY OPERATING LICENSE NO. DPR-38 AMENDMENT NO. 123' TO FACILITY OPERATING LICENSE NO. DPR'-47 AMENDMENT NO. 120' TO' FACILITY OPERATING' LICENSE NO. DPR-55 DUKE POWER COMPANY OCONEE NUCLEAR STATION', UNITS NOS. 1, 2 AND 3 DOCKETS' NOS.
50-269', 50-270 AND 50-287 8310110575 830929 PDR ADOCK 05000269 P
1.0 INTRODUCTION
AND DISCUSSION The storage capacity of the Unit No. 3 spent fuel pool at the Oconee Nuclear Station (ONS) is 474 fuel assemblies. The original design capacity of the pool was 216 fuel assemblies and the increase from 216 to the presently authorized 474 fuel assemblies was approved on December 22, 1975 by means of an amendment to the Unit's operating license. The amendment also included a supporting Safety Evaluation (SE) and an Environmental Impact Appraisal (EIA).
The limited storage capacity was in keeping with the expectation generally held in the industry that spent fuel would be kept onsite for a few years and then be shipped offsite for reprocessing and recycling of the fuel.
Reprocessing of spent fuel did not develop as had been anticipated, however, and in September 1975, the Nuclear Regulatory Commission (NRC, the Commission) directed the NRC staff (the staff) to prepare a Generic Environmental Impact Statement (GEIS, the Statement) on spent fuel storage.
The Commission directed the staff to analyze alternatives for the handling and storage of spent light water power reactor fuel with particular emphasis on developing long range policy. The Statement would consider alternative methods of spent fuel storage as well as the possible restriction or termination of the generation of spent fuel through nuclear power plant shutdown.
A Final Generic Environmental Impact Statement on Handling and Storage of Spent Light Water Power Reactor Fuel (NUREG-0575), Volumes 1-3 (the FGEIS) was issued by the NRC in August 1979. In the FGEIS, consistent with the long range policy, the storage of spent fuel is considered to be interim storage, to be used until the issue of permanent disposal is resolved and implemented.
One spent fuel storage alternative considered in detail in the FGEIS is the expansion of onsite fuel storage capacity by modification of the existing spent fuel pools. Applications for fifty such spent fuel capacity increases have been reviewed and approved. The finding in each case has been that the environmental impact of such increased storage capacity is negligible. However, since there are variations in storage pool designs and limitations caused by the spent fuel already stored in some of the pools, the FGEIS recommends that licensing reviews be done on a case-by-case basis to resolve plant specific concerns.
In addition to the alternative of increasing the storage capacity of the existing spent fuel pools, other spent fuel storage alternatives are discussed in detail in the FGEIS. The finding of the FGEIS is that the environmental impact costs of interim storage are essentially negligible, regardless of where such spent fuel is stored. A comparison of the impact costs of the various alternatives reflect the advantage of continued generation of nuclear power versus its replacement by coal fired power generation. In the bounding case considered in the FGEIS, that of shutting down the reactor when the spent fuel storage capacity is filled, the cost of replacing nuclear stations before the end of their normal lifetime makes this alternative uneconomical.
-2 This Environmental Impact Appraisal (EIA) addresses the environmental concerns related only to expansion of the Oconee Nuclear Station, Unit No. 3 spent fuel storage pool.
Additional discussion of the alternatives to increasing the storage capacity of existing spent fuel pools is contained in the FGEIS.
1.1 DESCRIPTION
OF THE PROPOSED ACTION By application dated March 10, 1983, and'supplemented by letters dated June 24 and 30, July 14, and August 8, 1983, Duke Power Company proposed an amendment that would allow an increase in the licensed storage capacity of the Unit No.
3 spent fuel pool from 474 to 825 fuel assemblies. The storage capacity would be increased by replacing the existing racks with new, more compact, neutron absorbing racks, similar to those installed in the Unit 1/2 spent fuel pool in December 1980.
This would provide storage for spent fuel generated at ONS while maintaining full core off load capability through 1990.
The environmental impacts of the ONS as designed, were considerd in the Final Environmental Statement (FES) relative to the continuation of constuction and operation of ONS issued March 1972. The purpose of this EIA is to determine and evaluate any additional environmental impacts which are attributable to the proposed increase in the SFP storage capacity of the Station.
1.2 NEED FOR INCREASED STORAGE CAPACITY The ONS consists of three generating units with a licensed power of 2,568 MWt for each unit.
Units 1 and 2 share a common SFP with a storage capacity of 1312 storage locations.
Unit 3 has a pool with a capacity of 474 storage locations.
All three units have 177 fuel assemblies in each core.
The modifications evaluated in this EIA are those proposed by the licensee to increase the pool storage capacity from 474 to 825 spaces in the Oconee Unit 3 SFP.
The proposed increase would be accomplished by replacing the existing fuel storage racks with new racks as mentioned above. The proposed rack design uses a nominal 10.60-inch center-to-center spacing. The old racks had a nominal 14.09-inch center-to-center spacing. This modification would extend spent fuel storage capability to October 1991 compared to September 1988 with the current capacity.
The increased capacity would extend the capability for a full core discharge from January 1988 to March 1990. This capability, while it is not needed to protect the health and safety of the public, is desirable in the event of a need for a reactor vessel inspection or repair. Such off load capability would reduce occupational exposures to plant personnel.
-3 1.3 FUEL REPROCESSING HISTORY Currently, spent fuel is not being reprocessed on a commercial basis in the United States.
The Nuclear Fuel Services (NFS) plant at West Valley, New York, was shutdown in 1972 for alterations and expansion; in September 1977, NFS informed the Commission that it was withdrawing from the nuclear fuel reproces sing business.
The plant is on land owned by the State of New York.
NFS's lease with the State of New York expired in 1980 and their license has been suspended. The State of New York has requested the utilities who own the spent fuel presently stored in the pool to remove it. The Allied General Nuclear Services (AGNS) proposed plant in Barnwell, South Carolina, is not licensed to operate. The General Electric Company's (GE) Morris Operation (MO) in Morris, Illinois is in a decommissioned condition.
Although no plants are licensed for reprocessing fuel, the storage pool at Morris, Illinois is licensed to store spent fuel.
On May 4, 1982, the license held by GE for spent fuel storage activities at its Morris Operation was renewed for another 20 years; GE is not accepting any additional spent fuel for storage at this facility.
2.0 THE FACILITY The principal features of the spent fuel' storage and handling at the Oconee Nuclear Station as they relate to this action are described here as an aid in following the evaluations in subsequent sections of this environmental impact appraisal.
2.1 THE SPENT FUEL POOL (SFP)
Spent fuel assemblies are intensely radioactive due to their fresh fission product content when initially removed from the core; also, they have a high thermal output. The SFP was designed fo'r storage of these assemblies to allow for radioactive and thermal decay prior to shipping them to a reprocessing facility. The major portion of decay occurs in the first 150 days following removal from the reactor core. After this period, the spent fuel assemblies may be withdrawn and placed in heavily shielded casks for shipment. Space permitting, the assemblies may be stored for longer periods, allowing continued fission product decay and thermal cooling.
2.2 RADIOACTIVE WASTES The station contains waste treatment systems designed to.collect and process the gaseous, liquid and solid waste that might contain radioactive material.
The waste treatment systems are evaluated in the ONS FES dated March 1972.
There will be no change in the waste treatment systems described in Section V.D and Appendix 111.3 of the FES because of the proposed modification.
-4 2.3 SFP CLEANUP' SYSTEM The SFP cooling and cleanup system consists of two circulation pumps, two heat exchangers, two filters, an ion exchangers, and the required piping, valves and instrumentation. This equipment is Pri a separate-toops.-- The pumps' draw water from the pool.
This flow is passed through the heat exchangers and then returned to the pool.
Approximately 100gpm in each loop is bypassed through the filter and ion exchanger to maintain the clarity and purity of the water.
Therefore, because we expect only a small increase in radioactivity released to the pool water as a result of the proposed modification as discussed in Section 3.2, we conclude the SFP cleanup'system is adequate for the proposed modification and will keep the concentraiions of radioactivity in the pool water to acceptably low levels.
3.0 ENVIRONMENTAL IMPACTS OF THE PROPOSED ACTION 3.1 NONRADIOLOGICAL The environmental impacts of ONS, as designed, were considered in the FES.
Increasing the number of assemblies stored in the existing Unit 3 fuel pool will not cause any new environmental impacts. The amounts of waste heat emitted by ONS will increase slightly (less than one percent), resulting in no measurable increase in impacts upon the environment.
3.2' RADIOLOGICAL 3.2'.1 INTRODUCTION The potential offsite radiological environmental impact associated with the expansion of spent fuel storage capacityiat Oconee Nuclear Station has been evaluated.
During the storage of the spent fuel under water, both volatile and non volatile radioactive nuclides may be released to the water from the surface of the assemblies or from defects in the fuel cladding. Most of the material released from the surface of the assemblies consists of activated corrosion products such as Co-58, Co-60, Fe-59 and!Mn-54, which are not volatile. The radio nuclides that might be released to the water through defects in the cladding, such as Cs-134, Cs-137, Sr-89 and Sr-90, are also predominantly non-volatile at the temperature conditions that exist in pool storage. The primary impact of such non-volatile radioactive nuclides is their contribution of radiation levels to which-workers in and near the SFP would be exposed. The volatile fission product nuclides of most concernithat might be released through defects in the fuel cladding are the noble gases (xenon and krypton),
tritium and the iodine isotopes.
-5 Experience indicates that there is little radionuclide leakage from spent fuel stored in pools after the fuel has cooled for several months. The predominance of t-he radionuclides in the pool water appears-to be radionuclides that were present in the reactor coolant system prior to refueling (which become mixed with water in the spent fuel pool during refueling operations), or crud dislodged from the surface of the spent fuel during transfer from reactor core to the SFP. During and after refueling, the spent fuel pool cleanup system reduces the radioactivity concentrations considerably.
A few weeks after refueling, the spent fuel cools in the pool so that the fuel cladding temperature is relatively cool,'approximately 180 0F. This substantial temperature reduction reduces the rate of release of fission products from the fuel pellets, and decreases the gas pressure in the gap between pellets and cladding, thereby tending to retain the fission products within the gap. In addition, most of the gaseous fission products have short half-lives and decay to insignificant levels within a few months.
Based on operational reports submitted by licensees, and discussions with storage facility operators, there has not been any significant leakage of fission products from spent light water reactor fuel stored in the Morris Operation (MO) (formerly Midwest Recovery Plant) at Morris, Illinois, or at Nuclear Fuel Services' (NFS) storage pool at West Valley, New York.
Spent fuel has been stored in these two pools which, while it
-was in a reactor, was determined to have significant leakage and was therefore removed from the core. After storage in'the onsite spent fuel pool, this fuel was later shipped to either MO or NFS for extended storage. Although the fuel exhibited significant leakage at reactor operating conditions, there was no significant leakage from this fuel in the offsite storage facility.
3.2.2 RADIOACTIVE MATERIAL RELEASED TO THE ATMOSPHERE With respect to releases of gaseous materials to the atmosphere, the only radioactive gas of significance which could be attributable to storing additional fuel assemblies for a longer period of time would be the noble gas radionuclide Krypton-85 (Kr-85).
As discussed previously, experience has demonstrated that after spent fuel has decayed 4 to 6 months, there is no longer a significant release of fission products, including Kr-85, from stored fuel containing cladding defects.:,
For the simplest case, we assumed that all of the Kr-85 that is going to leak from defective fuel is going to do so in the 12-month interval between refuelings. In other words, all of the Kr-85 available for release is assumed to come out of the fuel before the next batch of fuel enters the pool.
As far as potential dose to offsite populations is concerned, this is actually the worst case, since each refueling would generate a new batch of Kr-85 to be released.
As more and more fuel is added to the pool, one might think that this would increase the releases, but according to the terms of our model, this is not the case since all of the Kr-85 available for release has already left the defective fuel previously stored in the pool before the next batch enters, with the result that the annual releases
-6 are not cumulative but remain approximately the same.. In other words, the enlarged capacity of the pool has no effect on the total amount of Kr-85 released to the atmosphere each year. Thus, we conclude that the proposed modifications will not have any significant impact on exposures offsite.
Assuming that the spent fuel will be stored onsite for several years, Iodine-131 releases from spent fuel assemblies to the SFP water will not be significantly increased because of the expansion of the fuel storage capacity since the Iodine-131 inventory in the fuel will decay to negligible levels between refuelings for each unit.
Storing additional spent fuel assemblies is not expected to increase the bulk water temperature during normal refuelings above the 150OF used in the design analysis. Therefore, it is not expected that there will be any significant change in the annual release of tritium or iodine as a result of the proposed modifications from that previously evaluated in the FES. Most airborne releases of tritium and iodine result from evaporation of reactor coolant, which contains tritium and iodine in higher concentrations than the spent fuel pool.
Therefore, even if there were a higher evaporation rate from the spent fuel pool, the increase in tritium and iodine released from the plant as a result of the increased stored spent fuel would be small compared to the amount normally released from the plant and that which was previously evaluated in the FES. If it is des.ired to reduce levels of radioiodine, the air can be diverted to charcoal filters for the removal of radioiodine before release to the environment.
In addition, the Station radiological effluent Technical Specifications, which are not being changed by this action, limit the total releases of gaseous activity.
3.2.3 SOLID RADIOACTIVE WASTES The concentration of radionuclides in the pool water is controlled by the filters and the demineralizer and by decay of short-lived isotopes. The activity is highest during refueling operations when the reactor coolant water is introduced into the pool, and decreases as the pool water is processed through the filters and demineralizer. The increase of radioactivity, if any, due to the proposed modification, should be minor because of the capability of the cleanup system to continuously remove radioactivity in the SFP water to acceptable levels.
While we believe that there should not be an increase in solid radwaste from the SFP operations due to the modification,'as a conservative estimate, we have assumed that the amount of solid radwaste may be increased by 51 cubic feet of resin per year from the ion exchanger (an additional resin bed per year) and the filters (two additional filtersiper year). The estimated annual average amount of solid waste shipped from the ONS from 1973 to 1977 was about 37,000 cubic feet per year. If the storage of additional spent fuel
-7 does increase the amount of. solid waste from the SFP purification systems by about 51 cubic feet per year, the increase in total waste volume shipped would be less than 0.3% and would not have any significant environmental impact.
The present spent fuel racks to be removed from the SFP are contaminated. The licensee has chosen as a first alternative to decontaminate the racks and eventually sell the racks as scrap material.
A second alternative, should the first not prove feasible, would be to dispose of the contaminated racks as was done for the 1980 rerack of the Unit 1/2 SFP. If the disposal of the present Unit 3 racks is required, it is estimated that the ten racks would comprise approximately 8,250 cubic feet (as compared to the last Unit 1/2 rerack of fourteen racks comprising about 11,540 cubic feet of waste) of waste to be disposed of as low level waste. The old racks would be shipped, uncompacted, to the Barnwell site in South Carolina., The licensee is able to do this as the Barnwell facility does not have restrictions on compaction for in-state facilities such as ONS. This enables the licensee to avoid incurring a 5 man-rem dose that compaction would incur.
The total waste shipped from the Station will be increased by less than 0.5% per year when averaged over the lifetime of the Station.
This will not have a significant environmental impact.
3.2.4 RADIOACTIVITY RELEASED TO RECEIVING WATERS There should not be a significant increase in the liquid release of radio nuclides from the Station as a result of the proposed modification. The amount of radioactivity on the SFP filter and demineralizer might slightly increase due to the additional spent fuel in the pool, but this increase of radioactivity should not be released in liquid effluents from the Station.
The Station radiological effluent Technical' Specifications, which are not being changed by this action, restrict the total releases of liquid radioactivity from the Station.
3.2.5 OCCUPATIONAL RADIATION EXPOSURES We have reviewed the licensee's plan for the removal and disposal of the low density racks and the installation of the high density racks with respect to occupational radiation exposure. The occupational exposure for the entire operation is estimated by the licensee to be 22 person-rems.
We consider this to be a reasonable estimate because it is based on dose rates and occupancy factors for individuals performing specific jobs during the modification and experience gained by the. Oconee Nuclear Station, Units 1 and 2 Spent Fuel Pool Expansion.
The dose due to this operation is expected to be a small fraction of the total annual person-rem estimated for operating the Station.
-8 We have estimated the increment in onsite occupational doses which may result from the proposed increase in stored fuelassemblies. These are based on information supplied by the licensee and by the'utilization of relevant'assumptions for occupancy times and for dose rates in the spent fuel pool area.
The spent fuel assemblies themselves contribute a negligible amount to the dose rates in the pool area because of the depth of water shielding the fuel.
Based on present and projected operations in the spent fuel pool area, we estimate that the proposed modifications should add less than one precent to the total annual occupational radiation exposure and conclude that storing additional fuel in the pool will not result in any significant increase in doses received by workers.
3.2.6 RADIOLOGICAL IMPACTS TO THE POPULATION The proposed increase pf the storage capacity of the SFP would not create any significant additional radiological effects to the population.
The additional total body dose that might be received by an individual at the site boundary, and by the estimated population within a.'50-mile radius, is estimated to be less than 0.10 mrem/yr and 0.02 person-rem/yr, respectively. These doses are extremely small compared to the fluctuations in the annual dose this population receives from background radiation.
The population dose represents an increase of less than 0.01' percent of the dose previously evaluated in the FES forthe Oconee.Nuclear Station, Unit No. 3. We find this to be an insignificant increase in dose to the population resulting from the proposed action.
3.2.7 ENVIRONMENTAL IMPACT OF SPENT FUEL CASK/SPENT FUEL HANDLING ACCIDENTS Prior to commencing any removal of racks for the proposed modification, the spent fuel in the Unit No. 3 SFP will have been transferred to the Unit 1/2 SFP for storage. Also, the spent fuel cask is stored away from the pool so that prior to and during the modifications the possibility of an accident involving the fuel. assemblies from either the spent fuel cask or other loads is precluded.
Once the modifications are complete even though the pool will accommodate a larger inventory of spent fuel, we have determined that the use of the racks will not change the radiological consequences of a postulated fuel handling accident in the SFP area from.those values reported in the March 1972 FES for the Oconee Nuclear Station.
The environmental impact of a spent fuel shipping cask falling into either of the Oconee SFPs (Unit 1/2 or Unit 3) is given in the EIA dated September 10, 1976. These impacts are not changed because of the proposed modification of the Oconee Unit No. 3 SFP.
4.0
SUMMARY
The findings contained in the Final Generic Environmental Statement on Handling and Storage of Spent Light Water Power Reactor Fuel (the FGEIS) issued by the NRC in August 1979 were that the environmental impact of interim storage of
-9 spent fuel was negligible, and the cost of the various alternatives reflect the advantage of continued generation of nuclear power with the accompanying spent fuel storage. Due to the differences in spent fuel pool designs, the FGEIS recommended licensing spent fuel pool expansions on a case-by-case basis.
Expansion of the spent fuel storage capacity at Oconee Nuclear Station does not significantly change the radiological impact evaluated by the NRC in tha FES issued in March 1972. As discussed in Section 3.2.6 of this EIA, the additional total body dose that might be received by an individual at the site boundary or the estimated population within a 50-mile radius is less than 0.10 mrem/yr and 0.02 person-rem/yr respectively, and is less than the natural fluctuations in the dose this population would receive from background radiation.
The occupat ional exposure for the modifications (including rack decontamination for on-site storage) of the SFP is estimated by the licensee to be 22 person-rems.
This is conservative. Operation of the plant with additional spent fuel in the SFP is not expected to increase the occupational radiation exposure by more than one percent of the total annual occupational exposure at the Station.
5.0 BASIS AND CONCLUSION FOR NOT PREPARING AN ENVIRONMENTAL IMPACT STATEMENT We have reviewed the proposed modifications relative to the requirements set forth in 10 CFR 51 and the Council of Environmental Quality's Guidelines, 40 CFR 1500.6. We have determined, based on this assessment, that the proposed license amendments will not significantly affect the quality of the human environment. Therefore, the Commission has.determined that an environmental impact statement need not be prepared and that, pursuant to 10 CFR 51.5(c),
the issuance of a negative declaration to this effect is appropriate.
Dated: September 29, 1983