ML20248B918
| ML20248B918 | |
| Person / Time | |
|---|---|
| Site: | Three Mile Island  |
| Issue date: | 10/04/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20244A735 | List: |
| References | |
| FOIA-89-88 NUDOCS 8904110088 | |
| Download: ML20248B918 (8) | |
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i DISCUSSION OF PUBLIC COMMENTS
' AND STAFFRECOMMENDATiON ON USE OF EPICOR-II AT THREEMILEISLANDNbCLEARGENERATINGSTATION UNIT NO. 2 Prepared By l Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission October 4,1979 ,
8904110088 890405 PDR FOIA PDR PERLMAN89-88
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1.0 INTRODUC_ TION, l
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i As a result of the March 28, 1979 accident at The Three Hile Island Nuclear Generating Station (TMI), Unit 2 facility, a sig;ificart amount of radio-active ' contaminated water has been generated and collected in Unit 2 auxiliary bu11 ding tanks. At the present time, approximately 387,000 gallons of con-i
- taminated water is stored in these tanks. To process the contaminated water, !
1 1 Metropolitan Edison Company (the licensse) has designed and completed construc-tion of a system, EPICOR-II, which utilizes filtration end demineralization processes to remove radioactive materials from the water streams. {
The actual use of the EPICOR-II system, however, has been delayed pending reso-lution of the impacts associated with the operation of the EPICOR-II system. ,]
As & result of a filed by the City of Lancaster on May 20, 1979, the Con, mission directed the staff, on May 25, 1979, to prepare an environmental
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assessment for the use of EPICOR-II at TMI, Unit 2 and allow a period of 30 days I i
for public comment. A.. draft of the environmental assessment was released for public comment on August 20, 1979, and a total of 40 comments were received. i i
Of these 40 comments wo, including the Commonwealth of Pennsylvania, were in i I
agreement with the staff that the EPICOR-ll system should be used to decon- '
taminate the Auxiliary Building water at TMI, Unit 2. Only four of these 40 comments, The City of 1.ancaster, the Susquehanna Valley Alliance, the Common-wealth of Pennsylvania, and the Franklin and Marshall College were substantive in nature. The City of 1.ancaster and the Susquehanna Valley Alliance had ex-tensive legal and technical comments and were opposed to the use of the EPIC 0R-II system. The remaining 36 comments were letters from private indi-viduals or organizations.
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1 2.0 DISCUSSION OF COMMENTS Many commentors voiced objections to' discharging radioactive waste water into the Susquehanna River after being processed through the EPICOR-II system. As l stated in Section 1.0 of the assessment, the proposed action does not include the disposition of processed water from EPICOR-II, including the discharge of any processed water into the Susquehanna River. The use of the EPICOR-II system, as described in the revised environmental assessment, is only for the decontamination of the waste water and does not consider or permit disposal of the cleaned up water. Disposition of processed water will be covered in a LC 3afate assessment at a later date.
Several commentors voiced objections to the discharge of radioactive materials in gaseous effluents fran the operation of EPICOR-II. The dominant radioactive gases (Xe-133 and I-131) discussed in the draft environmental assessment have decayed to insignificant levels, due to their relatively short half-lives of 5.3 days for Xe-133 and 8 days for I-131. The expected radiaoctive gaseous release concentrations of these nuclides will be less than the minimum detect-able activity levels for the radiation monitor in the EPICOR-II ventilation system ductwork.
Several commentors questioned the public and occupational radi.ation expo-sure levels for various process operations of the EPICOR-II system. As dis-cussed in Section 4.0 of the environmental assessment, a design crigrion for the system was that occupational exposure should be maintained "as low as is I reasonably achievable." Therefore, the design was made consistent with the guidance of Regulatory Guide 8.8. We estimate that operation of EPICOR-II l
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t Q l will result in 1-5 man-rem of occupation dose. This estimate includes all activities involved in the operation of EPICOR-II, the handling and transfer of liners to and from the temporary storage facility, up to the time when the spent prefilter/deminerlizer liner and cask or spent demineralized liner'and cask 13 loaded on the truck for shipment to an approved burial facility. This estimate I
is a very small_cercentace fless than 1%) of_ tjgL otal annn21 nrennathnales3 t
at a nuclear oower plant. The dose to individuals involved in the operation of EPICOR-II will be within the limits of 10 CFR Part 20 arxf maintained as low as q 1
is reasonably achievable. The_ estimated maximum dose to an indMdel-4t the_. !
I site boundary on a continuous basis is less than 1 millirem. This dose includes j
i all of the handling operations and is less than 4% of the 25 millirem annual limit {
l in 40 CFR 190. >
Several commentors questioned the selection of the filtration and demineralize- l tion process incorporated in the EPICOR-II system vice an evaporation process. 1l The most viable alternative to a filtration / demineralize. tion process for the.
I cleanup of i_ntennedi.. ate-leval waste is_ the process of evaporation and subsequent j
condensation of the distilled water. An evaporation process was rejected on the N basis of theTnflead tim"e*for construction and the(Tcwer reliabilitlof such /
sys tems., Systems employing evaporators are not as reliable as filtration /de-mineralization systems due to such problems as pump failure and tpbe failure, !
resulting in evaporator outages approximately 30% of the time. Thus, a system employing an evaporator would be less efficient in reducing the large inven- i tory of intennedicte-level waste. Based on operating experience at other plants, the required u additional maio_tAnance;_an_an._eyapqtator system would re-sult_in higher occupational expns-es than fota filtr_ation[ demineralized system.
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_ 4 Several comments were directed.at the detailed aspects of the EPICOR-II system operation, such as preset values for automatic valve actuation and predeter-mined radiation levels for the various process radiation monitors. The detailed steo by_ step operational -
oroced_v.tes for the EPICOR-II system are described in the plant noma 1, as well as abnonnal, operating procedures which received close re.v.ieunsLey.aly.ation by the. NRC staff onsite as did the training of the system operating personnel .
Several comments addressed the removal of specific radionuclides by the EPICOR-II system such as tritium. The _ discussion of the _g.g.n.nentrations_gf s radionuclides that would be left in water processed by the EPICOR-II system_ . . . _ . . . . . ~
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J will be a subject of a selarate assessment for the disposition of,.t.he_ pro-cessed water. The system requirement to be capable of producing discharge quality water does not foreclose other options for the disposition of the pro--
cessed water in any way. <
Several operational comments on the interim and the concrete storage facilities for onsite storage of radioactive solid waste were questioned. Each cell in the interim storage facility is provided with a drip pan in which the liner is placed to collect any leakage or drippage. Leakage is not expected to occur since each liner is-dewatered prior to placement. The leak integrity of the l
liner, the_cel_ls_and the_dr.ip.. pan will gr. event.mi.gratio.n of . radioactivity _fr.gm l the liners to the groundwater. In addition to this protection, a well has been drilled in the proximity of the storage facility which will be monitored to assure that no activity migrates fran the liners to the groundwater. For the I concrete storage facility, the cell base plates are provided with a drain line i
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leading to a sump to collect washdowns or liner drippage. All liquid collected in the sump will oe sampled and analyzed for radioactivity and processed as re-quired.
3.0 RECOMMENDATIONS The staff has carefully reviewed and evaluated the comments from the 40 indivi-duals / organizations on the staff's Environmental Assessment on the Use of EPICOR-II at Three Mile Island, Unit 2, and incorporated the comn, ants into the j assessment, as appropriate. However,,the--. staff's posit _lan.renins_has.icsHL.
un.shanged. The need.for decontamination of the intermediate level waste water in the auxiliary building tanks is as evident now as it was several months ago f
and for the same reasons elaborated in the assessment. The .t.ank n = k e.s.
sentially full (approximately 95,000 gallons) of intennediate level waste water,
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and is no longer _ available for con,tingency purposes. The waste water in the auxiliary b'uilding tanks, and those inaccessible eraas of the building not yet decontaminated, continue to be a source of exposure to those workers requiring
, access to the building. The auxiliary building inleakage, including t"4w w__.._._. -
froaQhe makeup _and. purification system, highlights the need to decontaminate.e the tank and fluid system wa.ste water and those areas of the buildi.hg. which.
have never been decontaminated. Although the inlea_kage_
_ ka rate to the auxiliary-
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building,.is contained .in tanks, it doe,s.contribut.e to occupational exposure.s !
As decay of iodine and xenon radionuclides has minimized the potential for re-leases to the environment, the greatest impact of unprocessed waste water and nondecontaminated areas of the auxiliary building is to the occupational j 1
workers perfonning surveys, equipment maintenance, valve lineups, sampling l
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I operations, equipment modifications, etc. 'the stored waste water should be l
processed to lessen this impact and permit the decontamination of those com- -
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ponents and areas which continue to be a source of exposure.
The staff recommends processing for other reasons. Unit 2 capacity for sto. rag, of waste water is m+ 4 M?+erl c _tAhe_ filled at ,some. time. near the..e..n.d .of.Oc.tgker. .
i The staff does not recommend utilizing the available storage capacity (approx -
imately 225,000 gallons) in Unit I for several reasons. The o w >J tin u
.. -m storage wculd essentially'spreadf_. the contamination kroblem t_o JJqit.l It is
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likely that trace amounts of TMI-2 contamination would be depos.ited on piping and in tahs used for a'llowed processing or discharge of TMI-1 water. Conse--
l quently, subsequent processing and oischarge of TMI-l water under these circum- f stances would be inconsistent with the Commission's May 25 Statement. In ;
l addition, public perception might be that TMI-2 water was being processed i through the TMI-1 facility.
The procesting of Unit 2 waste water would allow for greater flexibility _in i
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the accommodation of both proct" sed and unprocessed water as the second por- 7.
tion of this assessment, dealp; with the disposition of processed water, is -
resolved. For example, processed water could be sto_ red in outdoor tanks or .
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in the onsite railroad cars or in _the_".B"B spent. fuel y_ool, o Due to the levels of activity and the attendant hazards in unprocessed intermediate level waste water, outdoor storage of such waste or storage in the B spent fuel pool would not be permitted.
l Delaying or deferring processing of intermediate level waste water does nothing for the long lived (30 years half-life) dominant isotope, Cs-137, but only pro-t 9
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-longs the time when pressinr' will be required. Delaying will also reduce the operational and storage flexibility that currently exists (e.g., the licensee
'being required to use an EPICOR-II tank for the collection and housing of un-processed waste water). !
The staff believes that ion-exchange is the best and most reliable technology to use in the processing of the intennediate level waste water, especially when viewed in the context of (1) the time required to construct'an adequate processing system in a timely fashion; and (2) the reliability and maintain- !
ability of the' processing system. An evaporator is a lo'ng lead time item and is anticipated to be "down" for maintenance two days out of every seven.
l Lastly, the staff's assessment predicted light exposure (i.e., less than I mrem) i i
to the maxirum individual from the nonnal operation of EPICOR-II. This exposure. !
l was calculated from expected releases of Xe-133 and 1-131, both of which have decayed to insignificant levels. Thus, the major contributors to the anticipat- l l
ed releases of radiaottive material in gaseous effluents no longer exist and l
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should no longer be a deterrant tu the processing of the waste water.
The staff concludes that since the operation of EPICOR-II does not constitute )
a significant environmental impact, the intennediate-level waste water should be processed to minimize the sources of exposure to the occupational workers required to enter the auxiliary building.
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