ML17192A772
| ML17192A772 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 06/06/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17192A770 | List: |
| References | |
| NUDOCS 8007010011 | |
| Download: ML17192A772 (10) | |
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UNITED ST ATES NUCLEAR REGULATORY COMMISSION WASHINGTON. 0. C. 20555 ENVIRONMENTAL IMPACT APPRAISAL BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATING TO THE MODIFICATION OF THE SPENT FUEL STORAGE POOL PROVISIONAL OPERATING LICENSE NO. DPR-19 AND FACILITY OPERATING LICENSE NO. DPR-25 COMMONWEALTH EDISON COMPANY Date:
DRESDEN NUCLEAR POWER STATION UNIT NOS. 2 AND 3 DOCKET NOS. 50-237 AND 50-249 l ~ -
June 6, 1980 J)~ o(,
t/ 0010/00 If
~
1.0 Introduction and Discusiion A Final Generic Environmental Impact Statement (FGEIS) on Handling and Storage.. of Spent light Water Power Reactor Fuel (NUREG-0575, Volumes 1-3) was issued by the Nuclear Regulatory Commission (NRC) August 1979.
The NRC staff evaluated and analyzed alternatives handlinq and storaqe of spent light water power reactor fuel with emphasis on-long range-policy.
Consistent with the long range policy, the storage of spent fuel addressed in the FGEIS 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 the onsite fuel storage capacity by modification of the existing spent fuel pools.
O~ the date of issuance of.the FGEIS (August 1979), 40 applications for spent fuel pool.capacity expansions )
were approved with the finding in each case that the environmental impact of the proposed increased storage was 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 detai 1 in the FGEIS.
- The finding *of the FGEIS is that the environmental impact-costs of interim storage are essentially negli-gible, 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, where spent fuel generation is terminated, the cost of replacing nuclear stations before the end of their normal lifetime makes this alternative uneconomical.
This.Environmental Impa~t Appraisal (EIA) incorporates the appraisal of environmental concerns applicable to expansion of the Dresden Unit 2.& 3 spent fuel storage pools, for additional discussion of the alternatives to increasing the storage capacity of existing spent fuel pools refer ~o the FGEIS *. This EIA consists of three major parts plus a summary and conclusion.
The three parts are: (1) descriptive material, (2) an appraisal of the environmerital impacts of the proposed action, and (3) an appraisal of the environmental impact of postulated accidents.
l~l Des~riotion of the Prooosed Action
.By application dated May 11, 1978, as supported by letters dated January 12, 1979, January 24, 1979, May 30, 1979, June 12, 1979, August.17, 1979, and October 19, 1979, Commonwealth Edison Company (the licensee) requested an amendment to PJ'.'Ovisional Operating license No. DPR-19 and Facility Operating License No. OPR-25 for Dresden Nuclear Power Station Units 2 and 3 (Dresden 2/3).
The proposed amendment would allow an increase in the storage capacity of each of the two spent fuel pools (SFPs) from l,420 to 3,780 fuel assemblies.*
The environmental impacts of Dresden 2/3.as designed, were considered in the Final Environmental Statement relative to.the continuation of construc-tion and operation of Dresden 2/3, issued November 1973.
The purpose of this environmental impact appraisal (EIA) is to determine and evaluate any additional environmental impacts which are attributable to the proposed increase in the SFP storage capacity for these two units.
1.2 Need for Increased Storage Capacity The Dresden Nuclear Power Station of Commonwealth Edison Company includes two 800.MWe and one 200 MWe nuclear generating units. Fuel storage pools are provided for each of the generating units. Currently there are 1,420 storage spaces in the spent fuel pools for Dresden Units 2 and 3 and 672 spaces in the SFP for Dresden Unit 1.
Dresden 2 and 3 have 724 fuel assemblies in each core while Dresden 1 has 464 fuel assemblies.
The modifications evaluated in this environmental impact appraisal are the proposals.by the licensee to increase the pool storage capacity from 1,420 to 3,780 spaces in each of the Dresden Units 2 and 3 spent fuel pools.
The proposed increase would be accomplished by replacing the existing spent fuel storage racks with new, more compact, neutron absorbing racks.
The porposed rack design uses a nominal 6.3 X 6.3 inch center-to-center spacing as opposed to the current nominal spacing of 6.5 X 12 inches.
This modification would extend spent fuel storage capability through 2005 compared to 1984 with the existing combined licensed capacity.
A more immediate necessity for expanded storage capacity arises from the prudent practice of maintaining sufficient room in the SFP to off-load a full core (724 fuel assemblies) should this be necessary for inspection or repair of reactor internal equipment or piping.
While this capability is not necessary to prote~t the health and safety of the public, it is desirable to reduce occupational exposures.
With the present SFP capacity for Dresden 2/3, the licensee will lose full core discharge capability*
af:er refueling in 1982.
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; on September 22, 1976, NFS informed the Col1ll1ission that they were withdrawing from the nuclear fuel reprocessing business.
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 deconmissioned condition. Although no plants are licensed for repro-cessing fuel, the storage pool at Morris, Illinois and the storage pool at West Valley, New York (on land owned by the State of New York and leased to NFS through 1980) are licensed to store spent fuel.
The storage pool at West Valley is not full but NFS is presently not accepting any additional spent fuel for storage, even from those power generating facilities that had contractual arrangements with NFS.
GE is also not accPpting any additional spent fuel for storage at the Morris Operation.
Construction of the AGNS receiving and storage station has been completed.
AGNS has applied for - but has not been granted - a license to receive and store irradiated fuel assemblies in the storage pool at Barnwell prior to a decision on the licensing action relating to the separation facility.
1.3 Radioactive Wastes The station contains waste treatment systems designed to collect and process the gaseous, liquid and solid waste that might contain radioactive material from both units.
The waste treatment systems are evaluated in the Dresden 2/3 Final Environmental Statement (FES) dated November 1973.
There will be no change in the waste treatment systems described in Section 3.5 of the FES because of the proposed modification.
1.4 Spent Fuel Pool Purification System Each of the two units has a completely i~dependent SFP and SFP cooling and purification system.
The following description of the SFP purification system is for Unit 2 with Unit 3 having an identical system.
The SFP purification system is part of the.pool cooling system.
It consists of a precoat filter, a mixed bed demineralizer and the required piping, valves and instrumentation. This purification system is similar.
to such systems at other nuclear plants which maintain concentrations of radioactivity in the pool water at acceptably low levels.
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 2.1, we conclude the spent fuel pool purification system is adequate for the proposed modification and will keep the concen-trations of radioactivity in the pool water to acceptably low levels.
2.0 Environmental Impacts of the Proposed Action 2.1 Nonradiological The environmental impacts of Dresden 2/3, as designed, were considered in the FES.
Increasing the number of assemblies stored in the existing fuel pools will not cause any new environmental impacts.
The amounts of waste heat emitted by each of the units will increase slightly (less than one percent), resulting in no measurable increase in impacts upon the environment.
If.. '* 2.2 Radiological 2.2.1 Introduction The potential offsite radiological environmental impacts a~s~ciated with the expansion of each of the spent fuel storage capac1t1es were evaluated and determined to be environmentally insignificant as ad-dressed be 1 ow.
The additional spent fuel which would be stored due to the expansion is the oldest fuel which has not been shipped and should have decayed at least four years.
During tne 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 f~om 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 radionuclides 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 nonvolatile.
The primary impact of such nonvolatile radioactive nuclides is their contribution of radiation levels to which workers in and near the SFP would be exposed.
The volatile fission product nuclides cf most con-cern that might be*released through defects in the fuel cladding are the noble gases (xenon and krypton), tritium and the iodine isotopes.
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 rad1onuclides in the spent fuel pool water appear to
. be radionuclides that were present in the reactor coolant system prior to refue 1 i ng (which becomes mixed with *water in the spent fue 1 poo 1 dur-ing refueling operations) or crud dislodged from the surface of the spent fuel during transfer from the reactor core to the SFP.
During ana after refueling, the spent fuel pool purification system reduces the ra-dioactivity concentrations considerably. It is theorized that most failed fuel contains small, pinhole-like perforations in the fuel clad-ding at the reactor operating condition of approximately 8µ0°F.
A few weeks after refueling, the spent fuel cools in the spent fuel pool so that the fuel clad temperature is relatively cool, approximately l80°F.
This substantial temperature reduction should reduce the rate of re-lease of fission products from the fuel pellets and decrease the gas pressure in the gap between pellets and clad, thereoy tending to retain the fission products within the gap.
In addition, most of the gaseous fission products have short half-lhes and decay to insignificant levels within a few months.
Based on the operational reports submitted by the licensees or discussions with the operators, there has not been any sig-nificant leakage of fission products from spent light water reactor fuel stored in the Morris Operation (MO) (fonnerly 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 detennined 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 i,n the off site storage facility.
2.2.2 Radioactive Material Released to Atmosphere With respect to gaseous releases, the only significant noble gas isotope attributable to storing adaitional assemblies for a longer period of time would be Krypton-~5. As aisc~ssea previously, experience has demon-strated that after spent fuel has decayed 4 to 6 months, there is no sig-nificant release of fission products from aefective fuel. However, we have conservatively estimated that an aaaitional 160 curies per year of Krypton-85 may be released from Doth units when the modified pools are completely filled. This increase would result in an additional total body dose to' an individual at the site boundary of less than.00015 mrem/
year. This d9se is insignificant when comparea to the approximately lOu mrem/year that an individual receives from natural background radiation.
The additional total Dody dose to the estimated population within a 50-mile radius of the plant is less than U.005 man-rem/year. *This is less than the natural fluctuations in th~ dose this population would receive from natural background radiation. Under our conservative assumptions, these exposures represent an increase of less than 0.1~ of the exposures from the plant evaluated in the FES for the individual at the site bound-ary (Table* 5.2) and the population (Table 5.4). Thus, we conclude that the proposed modification wil 1 not have any significant impact on expo-sures offsite.
Assuming that the spent fuel will be stored onsite for several years, Ioaine-131 releases from spent fuel assemolies 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 negli-gible levels between refuelings for each unit.
Storing additional spent fuel assemblies is not expected to increase the.bulk water temperature above the 125°F during normal refuelings 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 modification from that previously evaluated in the FES.
Most airborne releases from the plant result from leakage 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 r~sult of the increase in stored spen~ fuel would be small compared to the amount nor~ally released f~om.the plant and that which was previously evaluated in the FES.
If 1t 1s desired 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 eff'.uent '.e7hnical Specifications which are not being changed by this
~ct1on~ limit the total releases of gaseous activity from both units including the releases from both pools.
2.2.3 Solid Radioactiv* Wastes The concentration of radionuclides in the pool is controlled oy tne filter and the demineralizer and by decay of shortlived isotopes. The activity is high during refueling operations while reactor coolant water is intro-duced into the pool and decreases as the pool water is processed through*
the filters and demineralizer. The increase of radioactivity, if any, should be minor because the additional spent fuel to oe stored is rela-tively cool, thennally, and radionuclides in the fuel will have aecayea significantly.
While we believe that there should net be an increase in solid radWaste
- due to the moaification, as a conservative estimate ~e have assumed that the amount of solid radwaste may be increased by 36v cubic feet of resin a year from the demineralizer (two acditional resin oeas/year for each unit) from each unit. The ann~al average amount of solid waste shipped from Dresden Station Units l, Z and 3 during 1973 to 1977 is about 140,000 cuoic feet.per year.
Based on this, we estimate the ann~al average amount of solid waste from Dresden Z/3 is a~out 93,000 cubic feet per year. If the storage of addi ti ona 1 spent fue 1 aoes increase tne a.:iount of ~o 1 id waste from the SFP purification systems by ao.out 720 cubic feet per year, the increase in total waste volume shipped from o~esoen 2/3 woula De less tnan 0.8~ and would not have any significan~ environmental impact.
The present spent fuel racks to be re-:-:oved from the S~P are contaminated and will be disposed of as low level waste. The licensee has esti-mated that less tnan 20,000 cubic teet of racks will oe removed from the SFP because of the proposed modification. lf the olG racks are cut up.
the amount of solid waste would be less than 2,0UO CLoic feet.
Therefore, the total waste shipped from the station will be increased by less than o.~~
per year when averaged over the lifetil'! of tne station. This will not have a significant environmental.impact.
2.2.4 Radioactivity Released to Receiving aaters There should not be a significant increase in tne li~uid release of radionuclides from the station as a ~sult of the prcposed modifica-tion. The amount of radioactivity ir. the pool water ane1 on the SFP filter and demineralizer might slightly increase due to the additional spent fuel in the pool but this increase of raaioactivity should not result in a significant increase in raaicnuclioes in liq~ia effluents from the station.
The precoat filter removes insoluble radioactive mat:er from the SFP water. This is periooically oackf1usned to the filter slu~ge tank.
From this tank, the suspension of im;urities ana water is processed oy the 1 i quid radwas te system.
The demineralizer resin removes solu~le radioactive *.a~ter from the SFP water.
The resins are perioC1ica1ly flusned with water to the spent resin storage tank.
The water used to transfer the spent resin is re-turned to the liquid radwaste system for processing. The soluole raoio-activity wil1 be retained on the resins. lf any activity should be trans-ferred from the spent resin to this flush water, it *ould be removed by the 1 i quid raowaste system.
Leakage of water from the SFP, if a~1, would be oet~:ted by the pool low level alann, the flow glass in the arain line ana t~: level aetector on the skimmer surge tank. This water would oe transf:rreo to the liquid radwaste system. The radioactivity in the water wo~lG oe removed Dy the liquid radwaste sy~tern. There is nc leakage, at present. from the pool.
2.2.5 Occupational Exposures We have reviewed the licensee's plant for the removal and disposal of the low density racks and the ins~allation of tne high a!nsity racks witn re-spect to occupational radiatiJn expcsure.
The occu?ational exposure for the entire operation is estimated by the licensee to ru.nge from 18 to 47 man-rem.
We consider this to be a conservative estimate because it i 1s based on conservative dose rates and occupancy factors for indi-viduals performing a specific job during the modification. This opera-tion is expected to be a small fraction of the total annual man-rem burden from occupational exposure.
We have estimated the increment in onsite occupational doses at both units resulting from the proposed increase in stored fuel assemblies on the basis of information supplied by the licensee and by utilizing relevant assumptions for occupancy times and for dose rates in the spent fuel pool area from radionuclide concentrations in the SFP water. The spent fuel assemblies themselves contribute a negligible amount to the d.ose rates in the pool area because of the depth of water shielding the fuel.
The occupational radiation exposure resulting from the proposed actions represents a negligible burden.
Based on present and projected operations in the spent fuel pool area, we estimate that the proposed modifications should add less than one percent to the total annual occupational radiation exposure burden at both units. Thus, we conclude that storing additional fuel in the two pools will not result in any significant increase in doses received by occupational workers.
2.2.6 Impacts of Other Pool Modifications As discussed above, the additional radiological environmental impacts in the vicinity of Dresden 2/3 resulting from the proposed modifications are very small fractions (less than 13) of the impacts evaluated in the Dresden 2/3 FES.
These additional impacts are too small to be considered anything but local in character.
Based on the above, we conclude that an SEP modification at any other facility should not significantly contribute to the environmental impact of the Dresden Station and that the Dresden 2/3 SFP modification should not contribute significantly to the envirorvnental impact of any other facility.
3.0 Environmental Impact of Postulated Accidents Although the new high density racks will accommodate a larger inventory of spent fuel, we have determined that the installation and use of the racks will not change the radiological consequences of a postulated fuel handling accident and a fuel shipping cask drop accident in the SFP area from those values reported in the Dresden 2/3 FES dated November 1973.
Additionally, the NRC staff has under way a generic review of load handling operations in the vicinity of spent fuel pools to determine the likelihood of a heavy load impacting fuel in the pool and, if necessary, the radiological consequences of such an event.
In our Safety Evaluation dated June 1976 we concluded that the overhead crane
11:.I:,,
,. handling system and the spent fuel cask handling Technical Speci-fic~tions meet our requirements and are acceptable for handling spent fuel casks weighing up to 100 tons.
Because Dresden 2/3 will be prohibited from the movement of loads, other than a spent fuel shipping cask, with weight in excess of the nominal weight of a fuel assembly and handling tool over spent fuel assemblies in the SFP, we have concluded that the likelihood of a heavy load handling accident is sufficiently small that the proposed modifications are acceptable and no additional restrictions on load handling operations in the vicinity of the SFP are necessary while our review is under way.
4.0 Summary The ~EIS Jn Handling and Storage of Spent Light Water Power Reactor Fuel findings were
- ~hat the environmental impact of interim storage of 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. Because of the differences in spent fuel pool designs the GEIS recommended licensing spent fuel pool expansions on a case-by-case basis.
For Dresden 2/3, expansion of the storage capacity of the SEPs does not significantly change the radiological impact evaluated in the FES.
As discussed in Section 2.2.2, the additional total body dose that might be received by an individual or the estimated population within a SO-mile radius is less than.00015 mrem/yr and 0.005 man-rem/yr, respec-tively, and is less than the natural fluctuations in the dose this popula-tion would receive from background radiation.
The occupational exposure for the modifications of the SFPs is estimated by the licensee to be 18 to 47 manrem.
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 two units.
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 Part 51 and the Council of Environmental Quality's Guidelines, 40 CFR 1500.6.
We have detennined, 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, pur-suant to 10 CFR 51.S(c), the issuance of a negative declaration to this effect is appropriate.