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- .'l . ' . , c-INTERIM REPORT OF THIRD PARTY. REVIEW'OF'7.'- ! - c r- 9 ; . (!ib.?J -
{ THREE MIpE ISLAND, UNIT 1, STEAM GENERATOP REPAIR :., ' ' ;.; e l- . ,
" ~O J f / 8 /f A C Z ) d S '. y;< T ygun: E,G. LaA4 L W ( ;
t s ! R. F. Wilson - Vice President, Technical Functions- . l GPU Nuclear - . l ' m, .= N },
, Frepared by .
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THIRD PARTY REVIEW GROUP: ; -
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l Stephen D. Brown d. .).m Stanley A. Holland V 72
- 9 Arturs Kalning E Willian H. Layman S u 'y David J. Morgan - :u Richard W. Weeks Edwin J. Wagner - Chairman. .
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t 4 l Submitted for the Review Group p
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by: U i W - p.g. wer. . date* 9/27/82 l 8506140112 850125 PDR FOIA - DETJENS4-897 PDR
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i 4 PURPOSE: . l This is an interim report of the Third Party Review Grodp to ! - i . . + n. ' Q aluate a cart of the TMI-l Steam Generator Repair Programh=...'[),[Ei5'hh .- t that relating to the safety of conducting the proposed repair i. " of the steam generators while the plant is in a cold shutdowni-i *; f l ..yfi, condition, including the effects of the repair on the steam ; '(" f'i I generators and on the' remainder of the TMI-l plant. This -
. i interim report was requested by R. F. Wilson, GPU Nuclear,-
'h*1 i!.L on August 10, 1982 to obtain the Review Group's evaluation of.i ' ' ' ' Y' ,
this part of the steam generator program concurrent with decisi,on making on conducting the repair in THI-1. .As GPU T Nuclear completes the remainder of the overall repair. program, [ '., .' M ?- the Review Group will report its evaluationcof the remainder. ' of Scope of Review defined in the Charter for this Third.' , ( Party Review. . i CONCLUSION: , j Based upon the information developed by the repair program and . l summarized in the Safety Evaluation, the Review Group concludes,' I. - 4 that the proposed repair conducted on the TMI-l steam generators a!. 1 in conformance with the control systems described will not have adverse effects on the nuclear safety related items of the plant (including the steam generators) in the cold' shutdown i condition. This includes consideration of potential hazards ' from: f 1. Missiles generated by the explosive process. , i 2. Introduction of chemical residues in the steam ' generators, reactor coolant system or the reactor
- plant ambient.
- 3. Transmission of pressure pulses through air oristructures to sensitive items such as previously expanded :tubesi t' L
previously plugged tubes, other stcan generator structures - ! or safety related instruments and controls. (',
- 4. Handling of explosives in nuclear safety related' equip .
ment or structures (We note that no Review Group member, is expert in handling explosives. Acceptance of the' f response to this potential hazard is based on the
- procedure controls described in the-Safety Evaluatica, their compliance with the Laws of the State ofiPennsylvania and tne exclusive use of blasters licensed in accordance :
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with that Law) . -
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- 5. Occupational radiation exposures. - a ;; .d.8 .n i
.",' I This conclusion applies only to the safety of the plant, including .
the, steam generators, of conducting the proposed repair Wilai the0.*', t ., ..; i! ' ' plant is in the cold shutdown condition.' This conclusion does 4I b. ' not apply to the safety of returning the plant, with steam to service..
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J. gene,rators repaired by the proposed process, , Although efficacy of the repair is not a consideration.in the safety j of conducting the repair, it will be important to the safety'of -
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returning the plant service. GPU. Nuclear may elect to proceed ! : . - I- !' t with the proposed repair at substantial economic cost.: .The
-r Review Group therefore considers it appropriate to render an -
3 opinion now about.the efficacy of the repair sar it may affect. future safety considerations. ! Tne Review Group believes that the proposed repair, after. completion . " ' of the on-going qualification and when conducted in accordance with
't the control procedures, has a high probability of producing tube-: i-to-tubesheet joints adequate for a safe operation of the plant.
However, based upon industrial experience with expanded, unwalded pse tube-to-tubesheet joints in high pressure heat -exchangers, it. is l expected that greater leak rates will occur during normal operation '. .,I than typically experienced on new nuclear plant steam generators. - The Safety Evaluation covering return of the plant to service should'" consider this possibility , i 1 f APPROACH: I On April 12, 1982, R. F. Wilson of GPU Nuclear established a Third Party Review of the TMI-l steam generator repair program.. A Charter was supplied which defined the purpose, scope, member-
. ship and operations cf the Review Group. The evaluations of the Review Group have been conducted in conformance.with the. Charter. . , ,
The membership of the Review Group, selected by GPU Nuclear for expertise in the following technical specialties is: Affiliation _ f Specialty Name E. J. Wagner . Burns'and Roe,'Inc. Steam Generator Design ' Pennsylvani~a: Power & . Light . . Chemistry D. J. Morgan R. W. Weeks Argonne National Lab - Materials , Stress Analysis A. Kalnins Lehigh University '
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Safety Analysis W. H. Layman EPRI - NSAC S. A. Holland Duke Power Co. Plant Operations EPRI - NDE Center Non-Destructive S. D. Brown Examinations wh .
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- 3-E. G. Wallace of GPU Nuclear is a non-voting member who serves . -[..as liai ,
members have been present and participated in all meetingslof the ;l'M W II"' l
' " i' '! P Review Group.. . ,
It should be notac that the members act as independent individuals7'. * . . - <T* on this Review Group. Neither.their individual statements:nor- l
.their contributions to any reports of this Review Group are ' i .c. t 5ed.. <) A :l . r to represent the opinions or conclusions of the organizationsn erp]1{; '7',"
with which they.are affiliared. . , [ ,T . The evaluation reported in this interim report was conducted .: ,. f concurrently with evaluation of the. full. Scope of Review.5efinedtin.! 9!h,F g.. '
,1 the Charter. The Avaluation was conducted using reviews of
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,,l pertinent documents, submittal of written. questions ,to GPU '
Nuclear, written responses by GPU Nuclear, review of specialty , topics by individual members, presentation by cognizant GPU , Nuclear or contract,or personnel, Review Group meetings.and *, Executive Sessions of the Review Group. members only. . Ful'li day i '
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meetings of the entire Review Group were held on April.23, s May 20 and 21, and August 24 and 25, 1982.
- c 0; The focus of the evaluation of this interim report was the Safety 'k -
Evaluation of the TMI-l steam generator repair 20,distributed 1982 and to.the, of<its -
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Rev'iew Group (E. G. Wallace letter4). of AugustThe proposed repair described in .r~ j reference documents 1, 2 and f' this Safety Eva:uation is the explosive . expansion of the . top 17 ore . i 22 inches of the tubes within the top tubesheets of both. steam .,,'l'
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generators. The repair will be made on all, tubes which-willibe .' returned to service. The explosive expansion creates new pressure boundary joints between the reactor coolant and steam-side of the steani generators. i l l COMMENTS: During the review of the Safety Evaluation and supporting documents, I certain observation,s were made by the Review Group. These : l comments and the GPU Nuclear responses could be~ pertinent toIthe *! ' l conclusions of the Review Group in assessing the return of the l plant to service. They are therefore documented as follower. l. The Safety Evaluation states that the repair joints wiIl. be leak tight and meet the design
- bases of the ,,
As the Review Group stated under l original joints. Conclusion, the repaired joints will probably be' adequately ', However, the joints leak tight for safe operation. l ' should not be expected to be as leak tight in normal . .
'f operation as those of typical new steam generators.
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The Safety Evaluation forpotential-for the return of the plant isak., to , :w,g 4 service should consider the highe'r , jyp. $; . rates from reactor coolant to steam systems and the.> ,,,,g oy g. handling of resultant radioactivity discharges'such ais,: . .Ju N ; - M fron; the condenser air ejectors." GPU Nuclear,.agrined.. pf. ,, f.;c yy
- 2. Although indirect measurements provided some indicatione;,'.3,c.,-g, tne repair process qualification does not contain a '
direct metallographic examination to verify that the . ' . , ; ;,a,.. d . j;',, metallurgical structure of the tube material. iri the .
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expanded region is not degraded by tne expansion. . GPU Nuclear said that such ,a metallographic examination e.,. would be included in the qualification. ( ,
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- i. 3. Paragrapn 6.1 of the Safety Evaluation discusses , , .; . , .
residues left on the steam generator surfaces by p , < ' explosive expansion. The Review Group understands'that (,, ;;j the testing at Mt. Vernon showed greater amounts of . residue than expected based upon mock-up tests. Some 1,, cleaning is now expected to be necessary. GPU. Nuclear . :~ further advised that a material called Immunol is under I..: i consideration as a coating to facilitate removal of . residues. It would be applied to the tube surfaces ,e ' before the explosive expanding. l [ The Review Group suggested that specific. limits and- . appropriate check methods be included in. procedures to ; _, preclude existence of detrimental contamination from. , either the explosive residues or Inununol after completion ' of t.he repair. GPU Nuclear agreed. ;. , , ! 4. Paragraph 6.5 of the Safety Evaluation indicates that :the j steam generators w:.ll be isolated by temporary plugs , from the reactor coolant pystem during repair.6 Howeverc , a cognizant contractor person stated that,-based.upon-the [ Mt. Vernon testing, temporary plugs might not be used. . l The Review Group considered it.important to-assure thatt. . contaminants from explosives not be allowed ter travel into the reactor coolant system. GPU Nuclear agreed , , , and reiterated that the temporary plugs will be used. Y j
- 5. Paragraph 8.0 of the Safety Evaluation discusses the .
4 quality-assurance and quality control for the; repair. .
. The Reva.ew Group asked whether a quality plan existed
specifically for the repair. GPU Nuclear adviced that .- the quality actions are an integral part of each procedure
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- j and that all the repair activities wouM be . conducted . ',3, cr.ph.15]r;,i in accordance with written ' procedures and, the .TILI-1. ." 4 Jr: iib R yp Quality Assurance Plan. .-
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A specific quality check of .the adequacy' of :tho' oveirall ; t!y. 4 bl jni . explosive process (type of explosives, amount of. charger ..i. , c ,,.i i ., charge condition, correctness of . assembly, etc.) was it . - a g,, pu n ' suggestad by the Review Group as'the type of check that . , . ;. . g ,. g . might be identified by a specific quality plan for -the s... - , . 5 ,,i..;ce2 repair. . The intent of such a check wouM be to- detect ; ; ; m. qrn. any reptir process failure early rather than during i . . . . ,,+@ testing at the completion of. repair. This specific check p ip.m an might be conducted by actually explosively: expending a ,c,.2 , i . 3. p g : test joint periodically with production . explosives and. esi.4 i.. :;S;,, equipment. GPU Nuclear advised they would assure that t.:q pc,,; , the integral quality provisions of their procedures .u.- ,' constitute an adequate quality plan for the repair.and thakiap W q, . overall quality control check such as suggested would.. .. c. . . ,; . . ; , , be incladed. . e e e e e 9 e 1 e r -._ . ._ _ _.._. ._ . _ __ __}}