ML20247E471

Provides Views on Operation of EPICOR-II Sys for Processing Approx 400,000 Gallons of Contaminated Water Collected in Auxiliary Bldg Tanks

ML20247E471
Person / Time
Site:	Three Mile Island
Issue date:	10/09/1979
From:	Snyder B NRC OFFICE OF POLICY EVALUATIONS (OPE)
To:	Gilinsky, Hendrie, Kennedy NRC COMMISSION (OCM)
Shared Package
ML20244B007	List: ML20244B006 ML20247E388 ML20247E407 ML20247E419 ML20247E426 ML20247E437 ML20247E441 ML20247E471 ML20247E478 ML20247E482
References
FOIA-89-88 NUDOCS 8904030098
Download: ML20247E471 (4)

Text

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UNITED STATES Y

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LEARwAssmoTon, REGULATORY COMMISSIOq '

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MEMORANDLH FOR: Chairman Hendrie h Commissioner Gilinsky Commissioner Kenne.iy

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Commissioner Bradford Commissioner Ahearne hROM: Bernard J. Snyder, Acting Director, OPE .h - ,

SUBJECT:

OPERATION OF THE EPICOR-II SYSTEM AT TMI-2 1 The purpose of this memorandum is to provide views on the operation of the EPICOR-II System for processing approximately 400,000 gallons of contaminated

> water collected in auxiliary building tanks. This memorandum covers three technical and' policy aspects: process adequacy, solidification of resins, and suggested questions for the staff along with the most significant public coments . I understand that OGC is providing a separate memorandum regarding the litigative aspects.

Recommendation I recomend that the Comission approve operation of the EPICOR-II system as soon as the dewatering process for radioactive resins is demonstrated to eeet the criteria of no free-standing water and subject to other conditions discussed below. I recommend that a minimum time period for beginning -

solidification of resins now be established by the staff with Comission ~

concurrence, and subsequent shipments be made after that time only if resins are solidified. I suggest that you may want to obtain the staff's response to the questions and coments in Section III of this memorandum as part of your decision process.

Discussion I. Adequacy of the EPICOR,-II System The basic goal of decontaminating the~ collected water is to fix the radioactive fission products in a less mobile form and reduce the risk of exposure for the public Ud on-site workers. Processing of radioactive water by the use of isn-exchange resin bed demineralizers, such as EPICOR-II, is a well-established practice. From the operation of the earliest water cooled reactors to the present, both central station power plants and Naval propulsion reactor plants have used resin bed demineralizers. The performance of such systems is predictable and the process can be considered reliable and effective.

' I Contact >

Bernie Snyd&r, OPE \

63-43276 g40g8890329f PER LMA N89 PDR;

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I .The only viable' alternative

• to demineralization is to utilize an evaporative process. This alternative and some~of its disadvantages--

were briefly discussed in the staff's Environmental Assessment (Section

'6.0). However, the staff did not discuss a number of disadvantages that would result if an' evaporator was used. An evaporative process' would produce a very high activity sludge as .the " bottoms". of .the L evaporator. Probably these bottoms would have a much higher specific activity than the hottest EPICOR-II resins. -A frequently encountered problem is that evaporator bottoms containing chemical residues which 1

are difficult to solidify. Considering both the~ higher specific ,

i l activity and difficulty of solidification, a much higher man-rem exposure-would probably result if an evaporator were used instead of -

, 'EPICOR-II.

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. . o On balance, the EPICOR-II system, if properly operated, would be the best approach. The major but I believe manageable, concern in the handling of radioactive resins. Remote handling is required, with-dose rates expected to range from'1000 rem /hr. for the prefilter/deminerah ;

h: down to 3 rem /hr. for the post-filter. Since' 50 change-outs' of  !

demineralizers ar_e anticipated to be required to process this >ater, l the possibility is f airly high that leakage could occur from improper I

-connections. ~If leakage were _to occur it would be in arsas'outside "

the shield walls which require manned access to make and break the quick-disconnect fittings. Clean-up of any' spill could- be a significant-

. occupational dose. contribution. For this reason, I suggest that the Consnission require that a hydrostatic test of the system (with clean

' water) be conducted after each demineralized unit replacement,- before-introducing further contaminated water for processing. Furthermore, the licensee should be required to process the lowest activity water first. (Some additional. points are covered in the suggested questi6ns,Section III of'this memorandum).

I I .~ Solidification of EPICOR-II Resins As discussed at the last Comission briefing, the quest'on of solidi-

_fication of the EPICOR-II resins has not been fully resolved. Prior i to generating any radioactive resin, I believe resolution should be reached. In,_mak.in_g_ a decision for TNI-2, it should be recognized that the Scitest EPICOR-II resins will have a specific . activity of about 10 curies /ft3 (mostly Cs-137). This specific activity is roughly 5 to'10 times higher than the hottest resins encountered in normal operation of a nuclear power plant.

• Leaving the water in the tanks at TMI indefinitely would not satisfy what I believe to be the basic goal of reducing the mobility of the radioactive i contaminants, considering the 30 year half-life of Cs-137.

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• Although some reactor licensees'have solidified resins in the past,

, there is currently no NRC requirement for solidification.* Based on gL a staff survey, less than one-fourth 'of the currently operating;

. reactors nave solidified resins in the past. ~0f these, most have s

used UF (ureaformaldehyde) or cement solidification. processes. The UF process has been the source of recent problems at the low level waste burial grounds (i.e., leakage resulting from incomplete solidi-

. fication). Generally, it appears that cement systems have been more satisfactory. However,, since some problems have been experienced with both types of systems, whether. portable or permanent on-site any solidification process proposed by Met. Ed. will require detailed l review by NRC staff.

As presently designed, the EPICOR-II system does not have capability for solidification within the resin liners. 'Without changing the design of the liners, resins would have to be flushed out and processed through an add-on solidification system. This is not'an insurmountable problem. However, some increased radiation exposure to workers would result with . additional processing of the resins. Trade offs among I the options of

solidification in an add-on system; solidification within redesigned resin liners; or dewatering resins within the - l

- liners appear to be necessary.

Requirements placed on the licensees of the three operating comercial disposal sites presently specify no free-standing liquids in low- ,

level waste accepted for burial. In order to meet stricter enforcement I of this requirement, tests are,being conducted by Met. Ed. to ensure that the no' f ree-standing water criteria can be met. Earlier tests involving a simple suction pumping technique yielded about.a gallon .

'of water when the bottom of a "dewatered" liner was punctured. Since this procedure did not result in an acceptable product, improved ,

techniques including warm air drying are being tested. In addition, i there is concern that-an initially dewatered resin may yield further water af ter transportation ..You should obtain f rom the staff- the latest results from testing of the dewatering process before approving {

operation of EPICOR-II. Assuming improved dewatering techniques are  !

successful in meeting the no free-standing water criteria, test results should be made available to the waste burial f acility licensees, the appropriate states, and the public. Prior to any off-site shipment of EPICOR-II resins, the best possible dewatering process should be used (after conclusive demonstration with non-radioactive resins).

In order to reduce exposures and possible risks due to accidents, ,

handling of resin liners should be minimized at the TMI site. l l

• Although NRR established a Branch Technical Position in 1975 that solidification of resins should be required, this has not yet been implemented.

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Convaission

-4 l The' question.of solidifying EPICOR-II resins before shipment has

.been considered by the NRR and NMSS staffs. As you were told at.the-last briefing, there .is some disagreement between NRR and NMSS, but this disagreement appears to have been narrowed down only to the' issue of when a fully operational solidification system can be avail-able at the site. Based on the attached memorandum from William.

Dircks to Harold Denton, dated October 3, and further discussions

' with'the staff, I understand that.-both agree that unti1~a satisfactory.

solidification system is operating, dewatered resins should be shipped

• - to burial sites. Although not explicitly stated in the attached memorandum, presumably these resins'would have to meet the no free-  ;

j standing water criteria. 'I suggest you obtain confirmation of this '

from the staff,.in order to ensure meeting the requirements where ~

, LLW is buried. I also understant that NRR will provide you with

) .their best estimate as to how soon a satisfactory solidification system can be available at TM14 Both NRR and NMSS apparently agree that solidification should be carried out as soon.as possible, and .

p that-no -long-term storage cf resin liners should be considered at  !

[ the TMI' site. . '

Under the,present circumstances, the best course appears to be to proceed with EPICOR-11 processing and off-site shipment ofiresins. as~

soon as the dewatering process is- demonstrated to meet the no free-standing water criteria. A minimum time period for beginnin'g solidification ,

should be established now by the staff, with Comission concurrence and subsequent shipments should be made,after that time only if they are solidified.

L III.

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Suggested Questions for the-Staff (including major issues' raised in , '

public coments)

The following are some questions which were identified in OPE's review'which you may wish to' address to the ' staff:

1. If there was any leakage along the transfer pipe between' the O,8 Auxiliary Building and the EPICOR-Il building how would it be V

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8 detected and what corrective actions would be taken? Does the 5, / guard pipe surrounding the transfer pipe (which would contain any leakage) slope toward the EPICOR-Il building sump for gravity drainage?

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