ML20195F797
| ML20195F797 | |
| Person / Time | |
|---|---|
| Issue date: | 09/09/1986 |
| From: | Sniezek J Committee To Review Generic Requirements |
| To: | Stello V NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| Shared Package | |
| ML20151C834 | List: |
| References | |
| FOIA-87-714 NUDOCS 8609170458 | |
| Download: ML20195F797 (90) | |
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UNITED STATES 7 j
NUCLE AR REGULATORY COMMISSION
- e WASHINO TON, D. C. 20666
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s SEP 9 1986 MEMORANDUM FOR: Victor Stello, Jr.
Executive director for Operations FROM: James H. Sniezek, Chairman Comittee to Review Generic Requirements
SUBJECT:
MINUTES OF CRGR MEETING NUMBER 91 The Comittee to review Generic Requirements met on Wednesday, July from 1-5 p.m. A list of attendees for this meeting is enclosed (Enclosure 123,1986}.
L. Shotkin and W. Beckner (RES) presented for CRGR review the proposed ECCS rule revisions (Section 50.46) and proposed changes to Appendix K to Part 50.'
Included in this review package was a proposed Regulatory Guide that set forth the proposed guidance for use of more realistic modeling of ECCS performance should licensees and pemittees elect such modeling options. A proposed Comission policy paper recomending in favor of issuance of the proposed pack-age for public coment was provided with this CRGR review package. Enclosure 2 sumarizes this matter (Category 2 item). It should be noted that CRGR review of this matter could not be concluded a' meeting No. 91 and will be continued to a future agenda.
Enclosure 2 contains predecisional infonnation and therefore will not be re-leased to the Public Document Room until the NRC has considered (in a public forum) or decided the matter addressed by the information.
In accordance with the ED0's July 18,1983, directive concerning "Feedback and Closure on CRGR Reviews," the above item requires a written response from the cognizant office to report agreement or disagreement with the CRGR recomenda- l tions in these minutes. This response, which is required within 5 working days after receipt of these minutes, is to be fomarded to the CRGR Chairman and, if there is disagreement with the CRGR recomendations, to the EDO for decisionmaking.
Questions concerning these meeting minutes should be referred to Walt Schwink (492-8639).
AI., v mes niezek, Chairman Comit e to Review Generic Requirements
Enclosures:
As stated cc: (See page 2) ,
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. cc:, Comission (5)
SECY ;
- Office Directors r
! Regional Administrators ;
i CRGR Members i G. Cunningham I L. Shotkin W. Beckner l J. Reyes M. Fleishman J
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Enclosure 1 LIST OF ATTENDEES CRGR MEETING NO. 91 July 23, 1986 CRGR MEMBERS J. Sniezek, DEDROGR J. Heltemes, AE00 E. Jordan, IE R. Cunningham, HMSS J. Scinto, OGC W. Morris for D. Ross), RES .
B. Sheron for R. Bernero), NRR OTHERS M. Taylor J. Clifford D. Rasmuson M. Lesur M. Fleishman N. Lauben P. Boehnert L. Shotkin W. Beckner J. Reyes l
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' i Enclosure 2 to the Minutes of CRGR Meeting No. 91 Proposed Revisions to 10 CFR 50.46 (ECC5 Rule),
Appendix K and Related Regulatory Guide (draft)
L. Shotkin and W. Beckner (RES) presented for CRGR review the proposed ECCS (Emergency Core Cooling Systems) rule revision package that would take into account a considerable body of researen findings about c*di cooling performance since the issue (1973) of the existing ECCS rule. 6 copy of the vugraphs used in presenting this matter to CRGR are attached heeto.
CRGR was being requested to recommend in favor of t bnsmitt41 of the proposed ECCS rule revisions and a draft Regulatory Guide to the Comission for its approval to issue for public coment. Review of this propond CRGR review package was requested by memorandum dated Juda 12, l'JJ6, from R. Minogue to the CRGR Chairman, J. H. Sniezek. Included in this CRGR review package are the following items:
Proposed Comission policy paper coneerving the ECCS rule revisions.
Advanced notice of Proposed Rulersking,1./06/78 (FSciosure A).
- Summary of ECCS research (Enclosu.'a B).
Conservatism in Appendix K and Fn.46 (Ewosure C).
- RegulatoryAnalysis(EnclosureD).
Notice of Proposed Rulemaking Ifnclocute E)
Environment Assessmenu (Enclosure F).
- Draft Regulatory Guide (Enclosure r-).
In their presentation, the RES staff point \1 out tnt in addf tion to the above items, a technical document that sumarizes the emergency
- ore c0011:3 system (ECCS) research results used in support of this proposed ru1& ding effort would be ready for public coment about October 1986. This ratser extensive coerpendium (on the order of 10,000 pages) of research Nsults is timed at pro-viding the informed and interested readers with an nyerview of t.echnical bases that exist in support of the use of more realistic U.e., best es'limate) ECCS calculations in the licensing process. The RES staff also pointed out thac additional changes that would include in the added proposed information (Draft) about thoseRegulator)istic real ECCS predictiveGJide w models and date found acceptable to the staff.
The staff proposal for the ECCS rule revisions is irtended tc (1) allow certair.
changes and corrections to be made to the ECCS evalue' inn vielt without re-quiring any imediate reanalysis by applicants or licensees and (2) pmdt tae use of realistic calculations, along with uncertadn?" analyses, to be used ir, the evaluation of ECCS perfonnance. Applicants and heensas cculd slect to use these more realistic ECCS calculations but would r.ot be regidred to do so.
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. 2-They could also continue to rely on the use of the more conservative evaluation models based on the present calculational features in Appendix K. As to back-ground, Section 50.46 of 10 CFR Part 50 requires (and will continue to require) that calculations be perfortned to show that the ECCS will adequately cool the reactor core in the event of a loss-of-coolant accident (LOCA). Appendix K sets forth certain required and acceptable features that the ECCS evaluation models, used to perform these required calculations, must contain. The results of these calculations are used by the staff to determine the acceptability of the ECCS perfonnance for purposes of plant licensing. In many instances, these calculations result in technical specification limits on reactor operations (e.g., peak local power) in order to compl with the 2200*F peak cladding tem-perature limit and other limits of 650.46(y).b These limits can restrict the total power output and constrain optimal operation of many reactors (e.g., most Westinghouse plants) in terms of efficient fuel utilization, maneuvering capa-bility and surveillance requirements. According to the staff, removing un-necessary restrictions on plant operations could allow increased U.S.
electricity production, worth perhaps a hundred million dollars a year, without a significant loss of safety benefits to the public health and safety. In some cases, removal of these restrictions could also result in positive benefits to safety and to could alleviate certain system level restrictions (e.g., trip setting, LCOs) thu can result in spurious trips and unnecessary plant down-time. As examples, ,the staff noted that diesel generator reliability could be improved by .equiring less rapid start and loading times. Also, by allowing a higher neutron flux at the core center, less neutron leakage at the vessel wall would result, thus reducing reactor vessel weld embrittlement and the likeli-hood of crack propagation given very severe pressurized *.hermal shock (PTS) events. In general, the staff advised CRGR that the distortions created by artificial conservatisms in Appendix K can (1) adversely affect the overall safety of plant design and its operation, and (2) result in considerable di-version of both NRC's and industry resources to the conduct of analyses that are in fact not very relevant to risk, thus, taking attention away from more important safety issues.
The NRC, DOE (including AEC and ERDA), U.S. nuclear ir.dustry and foreign re-search sponsored on ECCS performance since issue (1973) of the present ECCS rule, was said by the staff to provide a sufficient technical understanding to show that the existing ECCS rule restrictions are more stringent than required.
Thus, the staff is recomending that the ECCS rule de amended to reflect this more realistic assessment of safety and to allow for the removal of unnecessary operating restrictions. This action was said to be consistent with tN 1973 Cosimission opinion published with the existing ECCS rule. A number of alter- l native rulemaking appronhes have been consiuered by the staff and eacn ap- I rm sch has been evaluated in terns of safety, impact on the industry, and
%e NRC and industry resourets require:1. As a result, the staff is recommend-mg the elimination of the r!quiremert to use the existing Appendix K features and tit unnecessary analytic conserv6tisms at the option of applicants ano !
M censees. The conservative ano: orescriptive nature of Appendix K is now be-lieved by the staff to be no longer necessary in view of the current improved
%owledge about ECCS performance. More realistic analyses, combined with un-certainty evaluations, is now thought by the staff to be a sound and acceptable citerrative sethod to demonstrate conformance with that principal performance criteria for LCCS as set forth by 650.46(b).
. . Based on the staff's presentation and its review of the proposed rulemaking package, CRGR offered the following principal coments and recomendations:
- 1. CRGR observed that the proposed rulemaking package was in need of further work to make clear what the staff means by its use of language such as inadequate, non-conservative, overly-conservative, etc. There was also a need for the staff to better define the nature of the problems found with use of certain of the required ECCS evaluation models. As examples where this further work was needed, CRGR noted the following areas:
- a. Ambiguity of language as used in the proposed Comission paper (pg.
4, first paragraph) where inadequacies of the required Appendix K models (e.g., discharge model) are discussed.
- b. Ambiguity was noted concerning the NRC staff resource impacts that might be expected should a majority of licensees elect to pursue the use of the more realistic ECCS performance calculations. CRGR sug-gested that the staff review the consistency (and ensure the valid-ity) of those various estimates such as are presented in Enclosure D (pp. 8 and 14), Enclosure E (pg.16), and in the proposed Comission paper (pg.11). The CRGR suggested that the potential NRC resource impacts attendant to this rulemaking should be clearly stated and placed 'up-front" in the Comission paper,
- c. CRGR noted that in Enclosure D (pg.14) the staff indicated that "the single most significant concern" about this proposed ECCS rulemaking was the potential for reopening ECCS rulemaking hearings that could cause ' major problems" and consume the time and talents of many en-gineers and attorneys. It was not imediately clear to the CRGR that this language was necessary in the rule package or was consistent with the estimated NRC resource burden of the proposed rulemaking (if indeed the litigative risks were as high as suggested by use of this language). CRGR noted that the proposed rulemaking was intended only to create an option for the use of more realism in the ECCS calcu-lations and would not be mandatory; thus, little or no safety benefit could be claimed by the staff to justify a very large NRC resource burden if this burden is expected to be brought about by extensive litigation and hearings on this matter. CRGR suggested that the staff consider use of language to reflect that the staff would further assess there potential litigative risks and the associated resource burdens when such matters can be better calibrated from :til public coments received on the proposed rulemaking. This further assessment could be made prior to the decision to proceed with a l final rule. '
- d. The language in Enclosure C (pg. 3) where various vendor calculations I are discussed relative to the proposed ECCS rule revisions was found to be ambiguous and without a conclusive bottom-line. CRGR suggested that the staff should revise the language to make it more conclusive or, if applicable, acknowledge that additional study was underway to better characterize the magnitudes of uncertaint), the known incon-sistencies and the degree of conservatism /non-conservatism involved in these vendor calculations.
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. . e. CRGR suggested that the language contained in Enclosure E (pg.17) about resource constraints brought on by the Gram-Rudman-Hollings legislation was unnecessary in the proposed rulemaking package and should be deleted,
- f. Regarding the proposed rule revisions, CRGR observed that the staff was, in some cases, changing "shall" to "must" and questioned the rationale and need for such unconsequential revisions--particularly when such changes were not being carried consistently throughout the rule. CRGR suggested that, normally, the staff should strive for a uniform internal consistency throughout the body of rules--otherwise staff should refrain from making such inconsequential and perhaps inconsistent revisions within this ECCS rule,
- g. The proposed rule language of par (2), pg. 21, Enclosure E was ques-tiened and the following revisions were suggested:
(1) "will" be imposed- " should be revised to "may"_ be imposed- "
since the nature of any operational restrictions made would be at the choice and discretion of the Director of NRR. (first line)
- 2) Add period and delete all language after the word "section."
fourthline)
Additionally, CRGR suggested that the staff seek additional legal opinion to support use of the word "and" as opposed to use of the word or in line four of par (2)--the concern being that an implied requiFement to use both the realistic and the conservative ECCS perfonnance calculations should not be given.
- h. CRGR suggested that the last sentence on pg. 24 of Enclosure E should be revised to give a more pointed reference to the ECCS performance criteria in 50.46(b).
- i. CRGR observed that Introduction section of the proposed (draft)
Regulatory Guide (RG) reads as though the staff does not yet know what needs to be done for the realistic or best estimate calcula-tions. This ambiguity could allow licensees to change their calcula-tional methods until such a time the staff provides more specific guidance on what to do (such as defining more specific examples of the realistic models that would be found acceptable by the staff for ECCS performance). CRGR suggested that the staff should consider revising this RG language to be somewhat more definitive. It should be made clear that use of the realistic or best estimate calculations are not being required by the ECCS rule revisions, and that if such calculations were elected for use, certain defined models set forth in this Regulatory Guide would be viewed as acceptable by the staff.
CRGR also noted that as a matter of style, the staff might wish to write the Regulatory Guide as though the proposed ECCS rule revisions l were now final. O l
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. . 2. CRGR identified several issues concerning the proposed ECCS rule revisions that could not be satisfactorily resolved during meeting number 91 and reconnended that these matters be continued for CRGR review at a future meeting. CRGR reconnended that the staff's and/or office positions on these matters be made more clear and solidified. These issues were:
- a. The staff is proposing to delete the Dougall-Rohsenow heat transfer correlation as an acceptable feature from the existing Appendix K evaluation models. CRGR observed that the potential impacts of this proposed deletion were not adequately assessed by the proposed ECCS rulemaking package. The act of deleting this model from Appendix K could result in some unspecified jeopardy for applicants or licensees who had received prior staff approval with on this feature in the ECCS evaluation modeling. CRGR inquired about the nature of "grand-fathering' being considered and the appropriateness of allowing plants to continue operation if the staff is now stating that the correlation has been determined to be non-conservative over certain of regions of the ECCS performance calculations. CRGR also ques-tiened what might be the reanalysis burdens required of the affected plants and of the NRC staff.
- b. CRGR questioned the language and stringency of the reporting re-ouirements being pr sed by the ECCS rule revisions. CRGR observed that the language would not' require error reporting by permittees and applicants--only licensees--pursuant to $50.72 and 50.73. CRGR questioned why the staff wanted to require each and every modeling or calculational error to be innediately reported no matter how small (e.g., l'F) in either the conservative or non-conservative direction.
The staff provided mixed views on the need for innediate reporting of such minor errors that were within that 50'F band now being cited in the proposed rule as "significant." CRGR also questioned why the staff saw a need to impose a rule upon itself to provide a 60-day response to the reported errors no matter how small or insignificant such errors were,
- c. CRGR noted that the provisions of the CRGR charter would require a clear determination by the Director of the Office of RES whether the proposed rule revisions would result in a decrease in the overall protection of public health and safety or the cormon defense and security and whether the proposal would result in cost savings for the NRC and/or the industry.
At their earliest convenience, the staff was requested to schedule a further CRGR review of proposed resolutions for those issues in paragraph 2 above.
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CPS PEVIEW OF FH0FOSED l
REVISION OF llE ECCS PllE 10 CFR 50.% AND APPE?0lX K l
.I JtLY 23,1986
) WILLIAM E00ER
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MOTKXFD-0JRRENT RU_LE 50.46(A) EQUIPES TIMT ENRGENCY CORE COOLING SYSTEPS "... E DESIGNED SUCH TilAT ITS CALO1ATED C0 CLING PEPF0ff#EE CONFORMS TO TIE CRITERIA SET FORT 11 IP' PAPAGRAPII(B)...APPEP0lX K, ECCS EVALUATION N0DELS, SETS FORTil CERTAIN E0l'IPED NO ACCEPTABLE FEATUPES OF EVALUATION ITDELS."
50.46(B) CRITERIA INCLl0E: (1) CALCULATED PEAK CLADDING TEMIPATUE LIMIT OF 2200*F,
- 2) t%XIP1F1 CLADDING OXIDATION OF 17% OF T11IOMSS, 3) f%XIPtf1 IlYDROGBl GDEPATION LESS TIMN 1%
OF HYPOTETICAL APIXNT FROM TOTAL ETAL EACTION, 4) C00LABLE tttrtil# PMINTAIED, AND
- 5) LONG TERM COOLING PROVIDED.
APPD0lX K CONTAIPS SKCIFIC FEATURES THAT EVALUATION ITDELS (81) itET CONTAIN (E.G., SOURCES OF EAT TO BE INCLUDED IN TE CALCULATIOPS), SECIFIC FEATURES EMS PIET EXCLl0E (E.G., STEAM C00 LING OrtY FOR LOW REFL0nD RATES), SKCIFICALLY EQUIRED 700ELS ( E.G., IT0DY BREAK FLOH),
AND MODELS M1101 AE ACCEPTABLE, BUT NOT EQUIRED (E.G., SPECIFIC EAT TPANSFER 00RRELATIONS).
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EACVM1tfD-APPEWIX K -
APPENDIX K AND 50.46 WE ISSlED IN 1975 PASED ON TIE DOLEDGE E ECCS EPF0FANCE AT T11AT TIE AFTER EXIITSIE EARINGS. CEPTAIF APfJLS E AFPEN)IX K EPE DUf! AT TilAT TIE TO E VERY CONSERVATIVE (E.G., DECAY WAT), PUT ERE USED TO 00VER IMERTAlflTY IN TE OVERALL [MERSTANDIPG OF ECCS PERFOMANCE.
FANY FEATUES OF ENS AE POT SPECIFIED BY APPEM)IX K. TIESE AEAS PAVE GENEPALLY BEEP TEATED <
00NSERVATIVELY ALSO DlE TO STAFF EQUIRENNIS OR DUE TO APR.ICANTS PROPOSING SIIPLIFIED AND/0R WNSERVATIVE PUELS.
RESEARDI Pdc 0RND SINCE 1975 PAS SHOWN Tl!AT TE ET EFECT OF TESE CONSERVATISM IS tRREhlISTIC, YET HIGLY CONSERVATIVE, EVALUATION N0DELS.
DISTORTIONS CREATED BY TIE USE OF ARTIFICIAL 00NSERVATISMS IN APPENDIX K CAN ADVERSELY AFRCT TE OVERALL SAFETY OF PLANT DESIGN APD OPERATICF EXAPPLES INCLlE OVERLY TIGfr TRIP SETR)INIS CAUSING NEEDLESS SCRAMS; OVEPLY TIGIT DIESEL GEERATOR START TIES EQUIREENTS (REDilCING DIESEL ELIABILITY); FLAT RADIAL POWEP PROFILES LEADING TO ilIGER FLUX ON VESSEL (PTS CONCERN); ARTIFICIAL DESIGN OF ECCS ACClMLATORS PRESENT APPENDIX K E0lilPEENTS RESULT IN CONSIDERABLE DIVERSION OF INDUSTPY E) AM) REGLATORY ESOUPCES TO SAFETY ANALYSIS THAT AE IN FACT IRRELEVANT, TAKIPE ATTENTION AWAY FROM PORE IPPORTAFT ISSLES FPC, DOE, IP00STRY AND FOREIGN ESEAROi ERF0PMD SIfE 1975 PROVIDES A TEOMICAL BASIS WHIOf PEPMITS M)RE EALISTIC TREATTE OF ECCS ANALYSES.
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CONSERVATIVE MARGINS IN APFDDIX K AP!ALYSES ESTINGHOUSE ANALYSIS: 1. ALL CURRENT APPDOIX K ASSIWTIONS KT = 2178F
- 2. NO FLOW BLOCVA PCT = 1962F
- 3. CATIGRT-PAKEL OXIDATION P00EL PCT = 2114F
- 4. CATIDRT-PAWEL OXIDATION AND B0 FLN BLOCKAE PCT = 1941F
- 6. 1979 #S DECAY EAT NO CATHCART-PAWEL OXIDATION PCT = 1716F TRAC-PF1/K01 EEST ESTIMATE CALQLATION WITH WORST CASE INITIAL AP0 B0lN)ARY CONDITIONS (SIMILAR TO CASE 6) PCT = 1403F TPAC-PF1/?001 BEST ESTIMATE CALCULATION WITH POST PROPARE INITIAL AND B0lf0ARY C0f0lTIONS PCT = 935F 6
l COMPARISON OF LOFT DATA WITH LICENSING
- EVALUATION MODEL PREDICTIONS ll Mr g g 3 3 j
DATA
...........NRC 200(s - !=. ./ ----- EXXON __
- *. t WESTINGHOUSE S !
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1975-1978: EAPLY RESEARGi 910WED EVIIDE OF LARGE 00NS3VATISM IN AM90lX K FEATURES. LITTLE INDICATION OF INDUSTRY St4 TORT TO EVISE APPD' DIX K. MAJOR PROBLEM OF AP'ALYSES DlE TO ERRORS IN EM.
1975: AERICAN MlYSICAL SOCIETY (APS) IDENTIFIED S CIFIC ECCS RESEAR01 NEEDS 1978: EAP1Y STAFF tnUHIS TO EVISE APPEM)IX K. ANPR PUBLISED IN FEDEPAL EGISTER IN DECE?EER,1978.
1979: TMI ACCIDENT TERMINATED FURTIEF WORK 1981: APPEN)IX K REVISION / GIN CONSIDERED 19R3: SECY-831472 INTRODUCED TIE CONCEPT OF USIFE EALISTIC MDDELS WITil lFCERTAINTY BOLNDS IN TIE LICENSif0 PROCESS. If0lSTRY IP0ICATES APPENDIX K IS LIMITING PLANT OPEPATION.
19811: INDUSTRY WAS PEOLESTED TO CAL 0 TATE TE EFECT ON APPROVED EMS OF CERTAIN PROFRID EVISIONS TO APPEM)IX K. BASED ON TIIIS ST10Y APO EXPERIENCES WIT 11 IrFPOVED E EM, STAFF ECIDED TO IT0 POSE A RlLE EVISION PASED ON SECY-83 f4 72.
1986: PROPOSED PULE, DRAFT EGULATORY EllIDE, AM) SLPMARY OF ECCS RESEARO{ C0PPLETED.
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ISSLES
- BPOAD SUPPORT FOR EVISING TE f1LE BY NRC STAFF, ACES, AND INDUSTRY: NO ItDICATION OF OPPOSITION FROM PUBLIC OR INTEPVENORS AT TilIS TIN.
BROAD SUPPORT FOR CURPENT RULE EVISION APPROAOi BASED ON SECY-83172 1 (I.E., EALISTIC EM WITH UNCEPTAINTY EVALUATION).
- WHILE TIEE IS BPGAD SUPPORT FOR A RULE PEVISION AND AGREEFUIT ON llE GENERAL APPROAOi, TEPE HAVE BEEN A WIDE VARIATION IN OPINIONS ON SECIFIC DETAILS. NPR, RES, M ELD STAFF HAVE HAD EXTENSIVE DISQlSSI(N ON TE DETAILS OF TE PROPOSED RULE. Tills HAS PESILTED IN A SIGNIFICANT DELAY, BUT HAS RESLLTED IN ALL VIEWS EING ADE00ATELY CONSIDERED AND A PROPOSED RLE THAT WE BELIEVE TO BE ELL THOLEHT OUT M S0lN).
A PAJOR AEA 0F STAFF DISCUSSION STIMLATED BY PEVIOUS CRGR KETING INVOLVED HOW DETAILED M PPESCRIPTIVE To t%KE TE RLLE. A VERY GENERAL PULE HAS BEEN PROFOSED, WITil AN ACGPPANYING EGlLATORY GUIE. TE CONTENT AFD LEVEL OF DETAIL OF TE EGULATORY GUIDE WAS ALSO AN ITEM 0F STAFF DISCUSSIONS.
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+0 OPTIONS (DNSIDEED A NO OlANGE PLANTS WOULD CONTINLE TO E RESTRICTED IN OPERATION BY CLFRENT PtLE.
LICENSEES WOULD CONTINUE 10 SEEK RELIEF Tim 0VG1 TE INTERIM SECY-831472 APO THROUGH EXEPPTIONS.
B PTDIFICATION AS IN 1978 #FR l -
SlESTANTIAL OMNES 50Ull) E DELAYED DOES NOT ESOLVE C0rfolTS ECEIVED EUTfD0 LNG P0RE Sl0STANTIAL 01 ANES.
C P0DIFY ERTAIN PARTS OF AFTENDIX K FMMN TO BE HIG1.Y CONSERVATIVE OR (FREALISTIC.
PLAffTS WOULD NO LONER BE LIMITED BY ECCS FILE RESTRICTIONS C0fGISTENT WITH NUREG-0885 00LICY OF IN00RFORATING ESULTS OF RESEAROI IN LI&NSING ADDITIffML AfMLYSES W0l!.D E ElUIED TO ENSlRE SlFFICIENT CONSERVATISM IN EMS.
RULE f%Y HAVE TD BE REVISED IN TE RIINE IF EW RESEARCH ESlLTS BEUPE AVAILABLE.
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P Ofi%O OL WO W 1E t C C A O O QI L
L fD L L I L A R A A - - - - A C C - - - -
D E
. FHOPOSED RA.E EVISION
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50.%(A)(1) -
(I) ...AFALYTICAL TEONIGE REALISTICALLY DESCRIBES TIE EEIMVIOR OF TIE PEACTOR .WiTEM..."
"GPPARISONS TD APPLICABLE EXPERIENTAL DATA..."
"tNCERTAINTY MJST BE AC00lt!TED ITIR Su llMT... TEE IS A IIIGI LEVEL 0F ITTABILIlY TIMT TE CRITERIA
[PAPAGPAPli B] W0llE NOT E EX0EED."
(II) "ALTEMMTIVELY, AN ECCS EVAllMTIft' K0El. mY E DEVELOFFD IN ON0ffMNCE WITl8...AFYDE)!X K..."
50.%(A)(2)
"ESTRICTIONS ON PEACTOR OPERATION WILL K IPFOSED...IF TE EVALIMTIONS OF ECCS COOLING PEPf0RNCE Suff1ITTED ARE NOT GPfSISTENT WIT 11 PARAGRAPHS (A)(1)(I) #3 (11)...#0 REullRED TO PRHECT PlRIC EALTil NO SAFETY."
50.t#6(A)(3)
...ESTImTE TE EFFECT OF ANY OiANE TD OR ERROR IN AN ACCEPTABLE EVAllRTION MI)EL..."
...SIf711FICANT OMNGE OR ERPOP IS (PE MIIOi HESll.TS IN...TEriERATURE DIFFERENT BY N)RE TIMM 50*F..."
"FOR EA01 SIGNIFICANT OMNGE TD, OR ANY ERPOR...EPORT TE NATUPE OF TE OMNGE OR ERPOR MC ITS ESTINTED EFFECT (N TIE LIMITING ECCS AMLYSIS
! ~
11
...EPORT A PROPOSED SOEDULE."
" ... FACILITlrS NOT HAVING NRC APPROVED INTEGPATED SOEI?JLING SYSTEM, A SOEDULE FOR ACHIEVIPC C0f?LIANCE WILL BE ESTABLISED BY llE NRC STAFF WITllIN 60 DAYS..."
"APrf 01ANGE OR ERROR...DOES NOT 00EDRM TO CRITERIA SET FORTH IN PARAGPAPH (B)...IS A REPORTAitE EVENT AS DESCRIBED IN 50.72 AND 50.73."
APPENDIX K I.C.S.B - DOUGALL-ROHSENOW NTELATION PB0VED AM) ANOTER EAT TRANSFER CORRELATION NtitFENCE UPDATED.
- II - CHANGES & DOCLPDITATION EQUIRENNTS TO
- 1. P90VE 20*F DEFINITION OF SIGNIFICANT OMNGE
- 2. PROVIDE A COPFLETE LISTING OF C0PRfIER IP0 GRAM OPLY IF REDISTED BY STAFF.
- 3. MAKE CONSISTENT WITH 01ANGES IN 50.%(A).
a .
- n
BF,GULATORYGUIDE STATES TilAT A 95% PROBABILITY IS ACCEf7 FABLE TO TE STAFF TO EET TIE EQUIREMM TO SHOW WITH A "...HIGH LEVEL OF PROBABILITY Tl!AT TE CRITERIA W0 LAD t0T E EXCEEDED." TWO SIGMA EETS PROBABILITY / CONFIDENCE EOUIREMMS.
- GEERAL GUIDANE ON WAT TIE STAFF WOULD EXPECT TO SLPPORT TIE 95% PROBABILITY E5TIMATE, BUT NO PRESCRIPTIVE PROCEDURE FOR UNCERTAINTY EVALUATION.
GEERAL GUIDAN& ON WHAT WOULD BE EXEutu IN KALISTIC P0DELS. BASIC EQUIREENT IS COPPAPISON TO APPLICABLE DATA.
DESCRIf7 TION OF PEALISTIC PDDELS PARALLELS APPENDIX K 79 HIGHLIGfr il0W REALISTIC P0DELS MIGHT DIFFER FRCM APPEPDIX K PElll0DS.
SECIFIC ACCEPTABLE REALISTIC P0DELS AND DATA BASES HAVE BEEN REPDVED FROM DRAFT EGULATORY GUIE AND AE INCLUDED IN PREFAE TO TW GUIE.
TESE PDDELS AND DATA BASES AE SUBJECT TO CHANGE BEFDPE CRAFT IS PUBLISHED BASED ON ONGOING STAFF AND EVIEW GROUP ECOMTNDATIONS.
SEEKING PUBLIC COPPENT ON EED FOR SRCIFIC PODELS AND DATA BASES IN EGULATORY GUIDE AND ON TE MODELS AND DATA PROPOSED TO E LISTED AS ACCEPTABLE.
13
Cft1PENDIlfi 0F ECCS RESEARGi FOR RFALISTIC _L_0_CA_ ANALYSI_S SifEARY OF ECCS KSEARGI IS EING PREPARED TO SUPPORT TIE RULEMAKING. IT BASICALLY RESPONDS TO ALL OF TE RESEARG1 NEEDS IDENTIFIED BY TE 1975 APS PEVIEW GROUP PURPOSE OF TE REPORT IS NOT TO DIECTLY SUPPORT SECIFIC C0lHITER CODES OR SECIFIC P0DELS TliAT MAY BE CONTAINEI' IN TE EGULATORY GUIDE (ALT 100G1 E AE ENSURING TliAT TIE D00MNT AND TIE EGULATORY GUIDE AE CONSISTENT).
REPORT WILL NOT BE ALL-INCLUSIVE D00MNT PROVIDING GEAT DETAIL APCUT EVERY P0 DEL.
FASIC PilRPOSE OF TE DOClf0T IS TO PROVIDE A "POAD MAP" TO ESEAR01 S0 TilAT TIE PEADER IS PROVIDED WITil AN OVEFVIEW OF M1AT HAS PEEN DOPE AND IS DIECTED TO OTTER D00MNTS FOR FURTER DETAILS. TilIS WILL ALLOW IPF0PND KADERS TO FORM TIEIR OWN CONCLUSIONS CONCERNING
1 14
EGlLATORY ANALYSIS-EFFECT OF RULE OWEE - -
CALCULATED RAK CLADDING TEPPEPATURES (PCT) DURING LAPGE BWAK LOCA (INCLl0 LNG (A' CERTAINTY B0l#DS)
M)ULD BE REDllCED. AFOUNT OF REDUCTION M)ULD E PLANT SWCIFIC APO ALSO DEPEND ON TIE ACCUPACY E TE CALClLATION. HOWEVER, TE REDUCTION IN CALCULATED PCT M)ULD LIKELY BE LARGE ENOUGH SO Tl!AT LARGE LOCA CONSIDERATIONS M)ULD NO LONGER BE LIMITING. OTER CONSIDERATIONS (E.G., DPE, SBLOCA)
MXJLD LIMIT PLANT OPERATION.
I SMALL BEAK LOCA (SBLOCA) P0DELS AE GENERALLY PEE EALISTIC T11AN LARGE BREAK P0DELS AND WOULD E LESS AFECTED BY TE PROPOSED RULE CHANGE, SBLOCA MAY ECOPE LIMITIPE.
REDUCED CALCULATED LARGE BREAK LOCA PCT COULD PESULT IN:
INCREASED ALLOWED PEAK LOCAL POER INCEASED TOTAL POWER CHANGES IN EQUIPPENT, SURVEILLANCE OR LC0 ALL TE ABOVE GIANGES W0llD LIKELY NOT E POSSIBLE AT TE SAE TIE AND MANY OTER FACTORS ALSO K00LD llAVE TO BE CONSIDEED SUCH AS:
i DNB LIMITS PLANT HARDWAE LIMITS 0TER CHAPTER 15 EVENTS t
4 15
L-EGULATORY ANALYSIS-PLANTS EXPFCTED TO BEEFIT GE AND ESTIt0 HOUSE PLANTS AE CENERALLY LIMITED IN OKRATING FLEXIBILITY AND/0R TUTAL POWER BY TE ECCS RULE AS EVIDENCED BY:
WRITTEN RESPONSES FRfE E Af0 ESliNGH0'JSE SIGNIFICANT RESOUPCES INVESTED BY E /.ND W IN IPPROVED ECCS CALCULATIONS RECENT BWR APPLICATIONS OF NEW E SARR filDEl.
TE E SAFER MODEL APPROVED LNER SECV-83-472 PROVIDES BWRS WITH TE CAPABILITY TO OBTAIN SIGNIFICANT REDUCTION IN 0 RATING LIMITATI0FS. IT MAY E PCRE DIFFICLLT TO EDUCE OPERATING LIMITATIONS ON W PLANTS THOUGH TE USE OF SECY-83-472 W/0 A RULE CHANGE.
BaW AND CE CLAIM NO BENEFIT FOR 'IEIR PLANIS.
16
- _ _ _ _ _ - _ _ _ -_ - _ _ _ _ _ _ _ .- ._ . -_ .1
KGILATORY ANALYSIS-FOTENTIAL COST SAVINGS WESTINGHOUSE CLAIMS MOST PLAT (IS AE LOCA LIMITED AND COULD E UPGRADED IN TUTAL POWER BY AFCilT 5% IF LOCA LIMITS REMNED. PRESENT VALE (10% DISCOUNT RATE) 0F SLOI A POWER INCREASE FOR A E PLANT ASSINING A 30 YEAR LIFE RANGES FROM $13M TO $1fl7M, WITH AN AVERAE FOR TE 27 1CURRENTLY OPERATING H PLANTS OF $68M. LOWER ASSifED DISC 0lWT RATES OR LONGEP PLANT LIVES M)ULD INCKASE TESE ESTIMATES.
INCREASING ALLOWED LOCAL RAK FGER (SAN TOTAL F0WER) RESULTS IN f0PE FLEXIBLE FUEL MANAGEPEFT AND MANEUVERING CAPABILITIES. TESE AE C0lTLICATED SUBJECTS AND LOCA LIMITS AE ONLY ONE OF SEVERAL LIMITING FACTORS. HOWEVER, SAVINGS OF $3-6M RR PLANT PER YEAR MAY E POSSIBLE.
GEERIC RELOAD ANALYSES AND FEER EANALYSES OFFER FOTENTIAL SAVINGS.
P01ENTIAL HARIWAE CHANGES, LCO, ETC. HAVE NOT BEEN EVALUATED 17
' me ,
LOCA LIMITS ON WESTING 00SE PLANTS CURENT TEONICAL SKCIFICATIONS AND UPDATED FSAR'S If0ICATED THAT:
15% OF M PLANTS ARE POT RESTRICIED BY APPENDIX K LOCA CRITERIA 0 (F = 2.32; LIMITING LBLOCA PCT < 2W0*F) 41% HAVE MDDERATE OPERATIONAL W STRICTIONS LIMITATIONS ON LOAD FOLLOWING LIMITATIONS ON STEAM GENERATOR TUBE PLUGGING (F = 2.32; LIMITING BLOCA 0
PCT >2000*F) 44% HAVE STRONG OKRATIONAL RESTRICTIONS LIMITATIONS AS ABOVE INCREASED COE t0NITORING EQUIREFENTS POSSIBLE DIFFICULTIES IN A01IEVING FULL POWER (E.G., D. C. COOK 2; F = 1.97; LIMITING LBLOCA PCT = 2187'F) 0 (GENERALLY F 2.?; LIMITING BLOCA PCT > 2100*F) 0 18
PEGJLATORY ANALYSIS _ SAFETY IWACT
, OiAP0ES MilOf FAY PEStiLT FP.0M PROPOSED PULE COULD ESULT IN R)SSIBLE KGATIVE Af0 POSITIVE SAFETY IMPACTS.
DO NOT ECutDO ATTETTING TO OllMTIFY NET IWACT ECAltSE:
EGATIVE ASRCTS EXAMINED WERE F00M) TO E St%LL COWARED TO LDCEPTAINTY IN OVERALL RISK MAtN OF TE POSITIVE IWACTS, MilOf WE BELIEVE TO E EAL, AE HIGILY SUBJECTIVE.
PAJOR RISK IWACT BELIEVED TO RESULT FROM POTENTIAL OfANGES TO PLANT E0llIPENT MilOi, mille POSSIBLE LNDER TIE PROPOSED RULE, IS NOT THOUGHT TO E A LIKELY RESULT.
TIE PROPOSED RULE P%Y:
ALLEVIATE OVERLY TIGHT SETPOINTS: REDLCING EEDLESS SQWIS ALLEVIATE OVERLY TIGiT DIESEL GENEPATOR START TIES; INCREASING DIESEL ELIABILITY PERMIT EUTRON FLt]X PROFILES M1IDI REDUCE FLlDICE OP' VESSEL APO CORRESi&OIPU PIS RISK POSSIBLY PERMIT POWER INCRFASE 19
t 1
SlftIARY A RULE EVISION HAS BEEN PROPOSED BASED ON INCREASED KKN_ EDGE OF ECCS PERFORMANCE GAIED SINCE TIE RULE WAS WRITTEN TE EFFECT OF TE RULE IS TO REDUCE LXtECESSARY PL#ff RESTRICTIONS WIT 11 A POTENTIAL FOR ECONOMIC BEFEFIT WITH EGLIGIBLE trtt.us ON SAFETY.
RULE INCOPPORATES TE EXISTING LICENSING ETICDS SO AS TO NOT PLACE ANY ADDITIONAL BURDEN ON PLANTS NOT EEDING OR DESIRING TO mal (E USE OF EH RULE PROVISIONS.
20
SOEULE FOR REVISION OF ECCS RLE ACRS PEETING TO UPDATE ECCS RULE ACTIVITIES APRIL 1986 NRR, DPR, ELD, RES CONCUR WITH PROPOSED RULE JtNE 1986 CRGR PEETING JlLY 1986 ED0 JULY 1986 COMISSION AUGUST 1986 NOTI & OF PROPOSED RLEMAKING ISSUED FOR RRIC 0(MENT NOVEPBER 1986 C0ffENT PERIOD ENDS MAY 1987 FINAL RULE RRISHED NOVEPEER 1987 i
O SCEIUfFJ38 PEPARATION AND PUBLI_ CATION _(E -
EGLATORY Gl!IT FOR EALISTIC ECCS ANALYSES
[
U.S. EXPERTS REVIEW 0F T ERMD-HYDRAULIC m DELS BEGINS APRIL 1986 NRR EVIEW OF DRAFT EGULATORY GUIT COPPLETED JtM 1986 PRELIMINARY PESILTS OF U.S. EXPERT EVIEW JlLY 1986 ES SELECTS mDELS AND DATA BASE FOR DRAFT EGULATORY GUIT FOR PUBLIC CLWENT OCTOBER 1986 DRAFT EGillATORY GUIE ISSIED FOR PUPLIC C0mNT NOVENER 1986 PUBLIC CutENT ERIOD ENDS MAY 1987 FINAL REL RlENOFENA PDDELS SELECTED JtE 1987 FINAL U.S. EXPERTS ECutENDATIONS FOR THERM-HYDRAULIC P0DELS JtLY 1987 RES SELECTS FINAL P0DELS Am DATA BASE OCTOBER 1987 FINAL EGULATORY GUIE ISSIED NOVEM ER 1987
.SOEDitE FOR PREPARATION AND PUPLICATION OF - -
"00rFENDILM OF ECCS RESEARCH FOR REALISTIC LOCA ANALYSIS" i
ROUGH DRAFT COPPLETED APRIL 1986 INEL PEVIEW BEGINS APRIL 1986 INE1. REVIEW C&PLETED JLLY 1986 FES EDITING COPPLETED ALGUST 1986 DFAFT ISSUED FOR PUPLIC C0rf9fT OCTOBER 1986 EXTERNAL EXRRT REVIEW BEGIPS OCTOBER 1986 PUBLIC CutENT PERIOD AND EXTERNAL EXKRT REVIEW CRFLETE MAY 1987 ES EVIEW/ EDITING COPPLETE OCT0PER 1987 FINAL REPORT PUBLISHED NOVEPBER 1987 9
a M.
.- t o' t
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SCHEDULE FOR REVISION OF ECCS RULE REGULATORY GUIDE AND RESEARCH COMPENDIUM RULE:
p ACRS NRR, DRR CRGR EDO C0pmISSION NPRM COMENT MTG ELD, RES MTG F'WL PERIOD Rt'LE CONCURRENCE ENDS O O O O O 4/86 6/86 7/86 O O O 7/86 8/06 11/86 5/87 1!/87 REGULATORY GUIDE:
T/H NRR T/H RES ISSUE COPMENT EXPERTS REVIEW EXPERTS FINAL FINAL FINAL FlalAL SELECTS FOR PERIOD REVIEW COPMENTS FUEL T/H EXPERT T/H EXFCtf StWIATORY RESULTS MODELS/ PUBLIC ENDS MODELS REVIEW RESULTS DATA CormENT G7IDF.
O O O O O O 1550eD O O 4/86 6/86 7/86 10/86 O O 11/86 5/87 6/87 6/87 7/87 11/3 ECCS RESEARCH COMPENDIUM:
ISSUED COPMENT FOR PUBLIC PERIOD ROUGH COMMENT ENDS INEL INEL DRAFT REVIEW RES O O COMMENT EDIT!!MG 10/86 5/87 RES REVIEW FINAL COMPLETE BEGINS REWRITES COMPLETED COMPLETE REPORT C- O O O 4/86 4/86 7/86 8/86 EXTERNAL REVIEW EXTERNAL 9 O REVIEW 10/87 BEGINS 11/87 COMPLETE
'M O 10/86 5/87
10 CFR 50.109 PROVISIONS 1 .
- 1. OIllECTIVE OF PROPOSED RULE:
TO MDDIFY 10 CFR 50.46 AND APPENDIX K TO PERMIT TIE LEE OF REALISTIC ECCS EVALUATION ft)DELS
- 2. GENERAL DESCRIPTION OF LICDSEE OR APPLICANT ACTIVITY:
PERMITS llSE OF CURRENT APP & DIX K FED ODS PERMITS USE OF REALISTIC EVALUATION MODELS, WITH SUfTORTING JUSTIFICATIOP TO VALIDATE PDDEL, C0rPARISONS TD EXPERIPENTAL DATA AfD UNCERTAINTY ESTIVATES
- 3. POTENTIAL OIANGE IN PUBLIC RISK:
PROPOSED RULE WOULD RESULT IN 5-10% INCEASES IN LOCAL POWER OR TOTAL POWER MlIOl WILL HAVE A E GLIGIBLE IfPACT ON RISK.
- 5% INCREASE IN FISSION PRODUCTS
- PCT PIET STILL REMAIN BELOW 2200*F DNB, TURBINE DESIGN ETC. h00LD LIMIT TIE Af0LWT OF MARGIN REDUCTION PEPMITTED UNDER PROPOSED RULE
- 4. POTENTIAL IPPALT TO EPPLOYEE RADIOLOGICAL EXPOSUE:
PRIFARY EFFECT OF PROPOSED RULE I?M)LVES CALCULATIONAL PETHODS - IFSIGNIFICANT EFFECT
- ON EPPLOYEE RADIOLOGICAL EXPOSUE IPPROVED FUEL UTILIZATION CAN PEDUCE RADIOLOGICAL EXPOSURE IF FUEL RELOADS CAN BE REDUCED
- 5. INSTALLATIONS AND CONTINUING COSIS:
PLANT SRCIFIC
- SEVEFAL MILLION DOLLARS PER YFAR SAVINGS IN IPPROVED FUEL LITILIZATION AfD OPERATION PRESENT VALLE OF 13-147 MILLION DOLLAPS (DEFU0 LNG ON PLANT) IN EERGY REPLACEPEFT COST SAVINGS ON TE LIR OF TE PLANT
1
- 6. POTENTIAL SAETY IPPACT:
HIGHER EAKING FACTORS RPMIT REDUCED FLUENCE AT VESSEL k'ALL WITil C0 RESPONDING REDUCTION IN PTS PISK ECCS EQUIPKNT NifTEPS, SIZES OR SURVEILUKE EQUIREfBITS MIGir EE PEDUCED AND STILL NET TIE ECCS DESIGN CRITERIA INCREASE DIESEL GEERATOR START TIE DURATION REDUCE NEEDLESS SCRAMS BY LOOSENIPU TRIP SETFOINIS
- 7. ESTIMATED FRC RESOURCE PURDEN:
311 STAFF YEARS FOR GENERIC 10 DEL EVIEW NO NET INCREASE OVER PLANNED EXPENDITUE IN CONJUNCTION WITl! SECY-83 f l72
- 8. _FUTENTIAL IfPACT ON DIFFERENT FACILITIES 1 DEPENDS ON IKM llE PLANE IS LIMITED BY LOCA RESTRICTIONS
- B8W AND CE CLAIM TliAT TEIR PLAfffS AE GEERALLY NOT LOCA LIMITED GE PLANTS ECEIVE REI.IEF FROM LOCA RESTRICTIONS THROUGH SAFER P0DELS APPP0XIMATELY 57 WESTINGHOUSE PLANTS LIMITED BY LOCA RESTRICTIONS U17 OPEPATING/10 UNDER CONSTRUCTION)
- 9. INTERIM OR FINAL RULE:
PROPOSED RULE, WlEN MADE EFECTIVE, F0ULD BE DOE S0 IN FINAL F0Pf1
Enclosure 4 to Minutes of CRGR Meeting No. 84 Proposed Broad-Scope Revision of General Design Criterion 4 (Leak-Before-Break)
G. Arlotto (RES) and J. Richardson (RES) presented for CRGR review a proposed broad-scope revision to General Design Criterion (GDC) 4 which reflects the findings of extensive analyses and research efforts indicatin acceptable for PWR licensees to apply leak-before-break (LBB)g that it isto technology demonstrate that postulated large pipe ruptures need not be treated as part of the design basis for PWRs (as is now required by NRC regulation) in certain licensing safety analyses that examine the dynamic effects of high-energy pipe break (e.g., pipe whip effects and jet impingement on safety systems). Copies of the briefing slides used by RES at this meeting are attached (see Attachments 1 and 2 to this Enclosure). The package of documents submitted by RES for review at this meeting were identified in a memorandum dated January 13, 1986, R. B. Minogue to J. H. Sniezek; that initial package included the following documents:
- 1. Draf t Connission paper, updated, "Proposed Broad-Scope Rule to Modify General Design Criterion 4 of 10 CFR Part 50," and enclosures as follows:
- a. Enclosure 1 - Proposed Federal Register Notice (Rule)
- b. Enclosure 2 "Assessment of Value-Impact Associated with Elimination of Postulated Pipe Ruptures from the Design Basis of Nuclear Power Plants" (Contractor Report by LLNL, dated March 29,1985).
- c. Enclosure 3 - Proposed Public Announcement i 1
- d. Enclosure 4 - Proposed Congressional Letters
- e. Enclosure 5 - Proposed Environmental Assessment
- 2. "Sumary of Proposed Generic Requirements for CRGR Review," da'ted June 3, 1985(updated).
Several documents not included in the initial package were submitted subsequently by RES in connection with this review; they were as follows:
- 1. Concurrence Sheet for Comission Paper in Item 1 above.
- 2. "Comparison Between U.S. and FRG Proposed Revision for Pipe Rupture Design Requirements at Nuclear Power Plants" (Attachment 3 to this Enclosure). j
- 3. "Backfit Analysis for Broad Scope Modification to Generic Design Criterion 4."
The proposed broad-scope revision to GDC-4 presented at this meeting was a follow-on to a similar matter considered earlier and in more limited scope by
CRGR in the context of the Comittee's review of USI A-2 on asymetric blowdown loads. (See Minutes of CRGR Meeting No. 47, dated October 14,1983.) In the resolution of USI A-2, the NRC staff provided the technical justification for the conclusion that large margins against unstable crack extension exist for certain stainless steel PWR primary coolant piping postulated to have large flaws, even when subjected to the safe shutdown earthquake in conbination with loads associated with normal plant conditions. Accordingly, the staff concluded that it is acceptable for PWR licensees to apply leak-before-break technology, in lieu of postulated large pipe ruptures at discreto locations specified by the staff, in licensees' analyses submitted for the purpose of resolving USI A-2. The CRGR recomended that the EDO accept staff's technical findings in that regard, but also noted that the staff's findings and the technical justification in support of those findings could apply more broadly to break locations other than those specified for consideration in USI A-2 and to assumptions made for PWR primary loop piping and components, for connected to the primary loops, and perhaps to the piping of othere.g., (piping balance-of-plant (BOP)) systems in the plant as well. The Comittee recom-mended a special staff effort to extend the USI A-2 conclusions more broadly.
The staff subsequently undertook an effort to amend GDC-4 to allow broader application of the leak-before-break technology, adopting a two step approach involving (1) development of a limited-scope interim rule to apply to the primary loop piping of PWRs, where sufficient technical evidence was already available and had been reviewed by the staff, ACRS, and CRGR, and (2) a follow on broad-scope rule to apply more generally to nuclear plant piping that could be found to meet appropriate acceptance criteria yet to be explored and developed. The limited-scope rule is now before the Comission for final approval (Ref. - Background Item 2.c). The staff hopes to issue for public coment the proposed broad-scope rule, considered at this meeting, in March 1986.
The staff believes that safety and cost benefits will be realized by the proposed rule change because it would pennit removal of pipe whip restraints and jet impingement barriers, required under the existing regulation, which (1) increase the time required and the occupational exposures associated with routine in-service inspections of affected piping (due to interferences created by the restraints / barriers involved) and (2) can increase the likelihood of pipe break due to stresses resulting from unintended thermal expansion interferences (e.g., a number that were inadvertently created when the high energy pipe break requirements were backfit extensively to existing PWR designs several years ago). The value impact analysis which supports the proposed rule change suggests a (lower-bound) best-estimate occupational dose reduction benefit of 34,000 man-rem for PWR and 86,000 man-rem for PWRs, considering an 85 plant total LWR population with an average remaining 35 years of life.
Estimated cost savings to utilities on the same bases are $186 million dollars for PWRs and $30 million dollars for BWRs.
The Comittee did not complete its review of this matter at Meeting No. 84, but raised points in the discussion at this meeting in the principal areas indicated in the following, to be addressed further by RES at Meeting No. 85 on February 5,1986.
- 1. The intended scope of the proposed GDC-4 revision should be clarified regarding applicability to piping in nonseismic category I structures which otherwise would meet the proposed acceptance criteria set forth by the staff for implementing the leak-before-break approach.
- 2. The value-impact analysis provided (which appears very similar to that provided in connection with a more limited scope LBB proposal considered earlier by CRGR) should be revised to make it more obviously applicable to and supporting of the broader-scope LBB action proposed now.
- 3. The staff's case for the potential safety improvements to be realized from approval and implementation of the proposed rule change seems to be generally overstated throughout the draft package. RES should consider revising the wording of the package in that regard to avoid the unintended suggestion that NRC should be requiring by order (rather than pennitting by rule change) the removal of pipe whip restraints, jet impingement .
barriers, etc.
- 4. RES should review usage of the terms important to safety and I safety-related throughout the package to assure proper usage consistent '
with the most recent guidance approved by the Commission in this area. )
1
- 5. The wording cf the proposed acceptance criteria should be revised to make clearer the staff's intent that, if dynamic effects of pipe rupture are j
excluded by licensees in their design analyses of piping systems affected, ASME Code margins (not necessarily "as built" margins) must be maintained. !
In many cases, for operating plants, the margins provided "as built" are !
very conservative (i.e., go considerably beyond code margin requirements).
- 6. RES should clarify the reference to IEB-79-14 in the proposed acceptance criteria. It does not appear that that bulletin should apply directly to some yet to be licensed (i.e., NTOL or CP) plants.
- 7. The wording of the draft rule should be revised to distinguish more ,
clearly (as does the Piping Review Committee Report) between the tore l general acceptance criteria proposed (which are intended as the sindatory, l Comission-approved requirements involved) and the more detailed "technical guidance" for interpreting / applying those criteria (which j appear to be intended more as SRP or Reg Guide type guidanc.e). Giving ,
both the criteria and the associated technical guidance the stature (or appearance) of mandatory requirements could be extremely troublesome in the practical implementation context.
- 8. RES should be prepared to discuss in greater detail at Meeting No. 85 the specifics of the associated SRP guidance that will be required by the staff to review licensee submittals expected under the revised rule; e.g.:
- a. Provide specific examples that will clarify the intent of the (proposed) acceptance criteria referring to "... fluid systems piping that operating experience has indicated is particularly susceptible to failure from intergranular stress corrosion (IG5C)."
4
- b. How will the proposed leakage detection criterion be applied with respect to pipe cracks that may be susceptible to plugging?
- c. How will acceptance criteria be interpreted / applied in the context of applicability to BWR piping (specifically, consideration of the applicability of the proposed acceptance criteria to new vs. old BWR piping)?
- d. With regard to the proposed criterion that "...LRB is not applicable to piping susceptible to failure from water hammer...," clarify whether licensees w'll be expected to provide detailed analyses of water hammer phenomenology and possible effects, or to demonstrate that the expected occurrence rate for water hammer is acceptably low.
ATTACHMENT 1 to ENCLOSURE 4 .
BROAD SCOPE GDC-4 RULE OUTLINE i
I O ABSTRACT 0 HISTORY l 0 SAFETY ISSUE 0 REASON FOR LIMITING LBB TO DYNAMIC EFFECTS 0 DEFINITION OF DYNAMIC EFFECTS 0 FOREIGN PRACTICES 0 VALUE/ IMPACTS 0 ACCEPTANCE CRITERIA 0 NRC RESOURCE DEMANDS 0 RELATED NRC REGULATORY ACTIONS I
I A i
i H_ ROAD SCOPE GDC-4 RULE ABSTRACT
! THIS RULE ALLOWS APPLICATION OF LEAK-BEFORE-BREAK TECHNOLOGY TO HIGH ENERGY FLUID SYSTEM PIPING TO DEMONSTRATE THE RULE THAT SPECIFIC PIP i RUPTURES NEED NOT BE TREATED IN THE DESIGN BASIS.
DEPENDS ON ADVANCED FRACTURE MECHANICS TECHNIQUES WHICH HAVE EXPERIMENTALLY VALIDATED. ALL REACTOR PIPING IN ALL REACTOR j
TYPES WHICH SATISFY RIG 0ROUS ACCEPTANCE CRITERIA CAN TAKE ADVANTAGE OF THE RULE. ONLY DYNAMIC EFFECTS ASSOCIATED WITH PIPE CONTAINMENT DESIGh,
! RUPTURES ARE EXCLUDED FROM THE DESIGN BASIS.
ECCS PERFORMANCE AND ENVIRONMENTAL QUALIFICATION ARE NOT IMPACTE THE REMOVAL OF PIPE WHIP RESTRAINTS, JET I BY THIS RULE.
IMPINGEMENT BARRIERS AND OTHER RELATED FACILITY DESIGN CHANGES IN OPERATING PLANTS, PLANTS UNDER CONSTRUCTION AND FUTURE DESIGNS ARE PERMITTED. AVERTED RADIATION EXPOSURES ARE EASURED IN
! 10,000'S OF MAN-REM. COST SAVINGS ARE MEASURED IN $100 i'
MILLION'S.
i l
)' _ _ _ _ - _ - _ _ _ _ .
3 BROAD SCOPE GDC-4 RULE HISTORY 0 JUNE 14, 1983 ACRS IN LETTER TO EDO SUPPORTS REGULATORY APPLICATION OF LEAK-BEFORE-BREAK TECHNOLOGY TO PRIMARY COOLANT LOOP PIPING 0F PWRS.
0 OCT, 14, 1983 CRGR MINUTES NUMBER 47 OBSERVES THAT "FINDINGS CONCERNING LBB HAVE BROAD IMPLICATIONS THAT G0 BEYOND RESOLUTION OF THE A-2 ISSUE .... FINDINGS COULD EXTEND TO OTHER BREAK LOCATIONS (AND TO)
PIPING CONNECTED TO THE COOLANT SYSTEM AND PERHAPS TO THE PIPING 0F OTHER SYSTEMS IN THE PLANT."
0 JUNE 29, 1984 NRR REQUESTS RES TO UNDERTAKE RULEMAKING "T0 DETERMINE THE APPROPRIATE DYNAMIC EFFECTS TO BE CONSIDERED FOR PIPING SYSTEM FAILURES. THERE IS A NEED FOR RULEMAKING THAT COULD ALLOW LESS THAN FULL DOUBLE-ENDED PIPE BREAKS."
!' BROAD SCOPE GDC-4 RULE i
) HISTORY (CONTINUED) i O DEC. 4, 1984 RES SPONSORS RULEMAKING COVERING ALL FLUID SYSTEM
! PACKAGE STATES "THE SCOPE OF AFFECTED PIPING.
- PIPING HAS NOT BEEN DETERMINED: HOWEVER, AT THE VERY LEAST, PRIMARY SYSTEM PIPING OF PWRS WILL BE f AFFECTED."
'1 APRIL 1, 1985 USNRC PIPING REVIEW COMMITTEE (NUREG-1061, VOLUME I O
- 5) WRITES: "THE COMMITTEE BELIEVES THAT LBB l TECHNOLOGY ... MAY BE APPLIED .... IN HIGH ENERGY FLUID SYSTEMS INSIDE AND OUTSIDE THE CONTAINENT."
THEIR HIGHEST PRIORITY RECOMMENDATION IS TO "USE l
LBB CRITERIA RATHER THAN DOUBLE-ENDED GUILLOTINE l
BREAK IN DESIGN OF PIPING."
0 JULY 1, 1985 A PROPOSED LIMITED SCOPE MODIFICATION TO GDC-4 i
DEALING WITH ONLY PRIMARY COOLANT LOOPS OF PWRS IS l
' PUBLISHED. THIS FAST TRACK RULE BENEFITS MANY NT0LS AND DOES NOT REQUIRE FURTHER ACRS OR CRGR REVIEW. LIMITED SCOPE RULE STATES "THE C0ffilSSION WILL PROPOSE A BROADER AMENDMENT TO GDC-4 COVERING l
- ALL REACTOR PIPING IN ALL REACTOR TYPES."
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J BROAD SCOPE GDC-4 RULE i SAFETY ISSUE
' APPR0XIMATELY 15,000 PIPE WHIP RESTRAINTS IN SERVICE TODAY OF VARYING MORE SIZES AND DESIGNS (INSTALLED AT A COST OF ROUGHLY $2 BILLION).
THAN 100,000 EXPERIENCE YEARS ACCUMULATED WITH PIPE WHIP RESTRAINTS, WITHOUT HOWEVER, EVEN ONE INSTANCE WHERE A PIPE WHIP RESTRAINT WAS INDIAN POINT, DUANE ARNOLD AND NEEDED TO PERFORM A SAFETY FUNCTION.
MAINE YANKEE, WHICH TO DATE REPRESENT THE MOST SEVERE LEAK / BREAK PIPING PROBLEMS IN SERVICE, DID NOT REQUIRE PIPE WHIP RESTRAINTS TO l
l MAINTAIN SAFETY. WE BELIEVE FOREIGN EXPERIENCE IS SIMILAR.
PIPE WHIP RESTRAINTS DEGRADE SAFETY BY LIMITING THERMAL EXPANSION W l CONTACT BETWEEN THE RESTRAINT AND PIPE OCCURS DUE T0:
A. ANY OF THE ESTIMATED 2000 LOCKED (FAILED) SNUBBERS NOW INSTALLED i LOCALLY RESTRAINING THERMAL MOTION. (APPROXIMATELY 40,000 SNUBBERS IN SERVICE, WITH 4000 FAILED "FREE" AND 2000 FAILED i "LOCKED").
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- t BROAD SCOPE GDC-4 RULE a
SAFETY ISSUE (CONTINUED) l B. INABILITY TO LIMIT, CONTROL OR ESTIMATE THE INFLUENCE ON THERMAL 4
GROWTH OF PIPE SUPPORT GAPS.
C. DIFFICULTIES WITH MAINTAINING TOLERANCES AND ALIGNMENTS IN PIPE WHIP RESTRAINTS, WHICH IN THE COLD CONDITION MAY BE SEVERAL INCHES AWAY FROM PIPING, WHILE DURING OPERATION ARE TO BE A FRACTION OF AN INCH AWAY IN SOME CASES.
THESE CONTACT PROBLEMS MAY CAUSE CRACKS TO GROW AT LOCATIONS NOT PROTECTED AGAINST PIPE RUPTURE BECAUSE OF MODIFIED STRESSES.
1 PIPE WHIP RESTRAINTS LIMIT ACCESSIBILITY FOR AND DIMINISH d
EFFECTIVENESS OF INSERVICE INSPECTION WHILE INCREASING WORKER RADIATION EXPOSURES.
)
-- - --__-- - -__ - - _ ____________________ __ ^ - - * - - - - - - - - _ _ _ _ _ _ _ _
7 BROAD SCOPE GDC-4 RULE REASONS FOR LIMITING LBB TO DYNAMIC EFFECTS 0 DYNAMIC EFFECTS LEAD TO THE PLACEMENT OF COUNTER PRODUCTIVE HARDWARE WHICH NEGATIVELY AFFECTS PLANT PERFORMANCE IN TERMS OF DEGRADED SAFETY AND INCREASED COSTS.
O LEAKS, VALVE MALFUNCTIONS AND OTHER SOURCES OF BLOWDOWN IMDOSE REQUIREMENTS FOR CONTAINMENTS, ECCS AND ENVIRONMENTAL QUALIFICATION WHICH CANNOT BE ELIMINATED BY. INVESTIGATING PIPING i INTEGRITY.
O IF LBB IS APPLIED TO CONTAINMENT, ECCS AND ENVIRONMENTAL QUALIFICATION DESIGN BASES TO ELIMINATE THE DEGB ACCIDENT, THEN A REPLACEMENT PIPE RUPTURE ACCIDENT MUST BE DEVELOPED FOR THESE ASPECTS OF FACILITY DESIGN.
0 MAJOR LONG TERM RULEMAKING WOULD BE NEEDED TO ADDRESS OTHER THAN DYNAMIC EFFECTS, THEREBY FORESTALLING IMMEDIATE PAYOFF IN ELIMINATING PIPE WHIP RESTRAINTS, JET IMPINGEMENT BARRIERS AND i UNDERTAKING OTHER BENEFICIAL FACILITY MODIFICATIONS.
i
1 BROAD SCOPE GDC-4 RULE i
- DEFINITION OF DYNAMIC EFFECTS 0 PIPE RUPTURE GENERATEC NISSILES (INSULATION, PIPE SUPPORT BOLTS, ETC.).
l 0 PIPE WHIP AfiD OTHER PIPE BREAK REACTION FORCES.
4 i
! O JET IMPINGEMENT FORCES.
! O DECOMPRESSION WAVES WITHIN THE RUPTURED PIPE (AFFECTS PIPE 4 COMPONENTS AND THEIR INTERNALS).
i O PRESSURIZATION IN CAVITIES, SUBCOMPARTMENTS AND COMPARTMENTS, i EXCEPT WHEN THESE VOLUMES ARE PART OF THE CONTAINMENT SYSTEM.
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1 BROAD SCOPE GDC-4 RULE .
(SOURCE:
INTERNATIONAL LBB SEMINAR ON OCT 28-30, 1985)
FOREIGN PRACTICES:
GENERAL NOTES: 1. NO NATION ACCEPTING OR CONSIDERING LBB AT THIS TIME WILL MODIFY REQUIREMENTS FOR CONTAINMENTS, l ECCS OR ENVIRONMENTAL QUALIFICATION.
- 2. EVERY NATIONAL ACCEPTING OR CONSIDERING LBB AT THIS TIME WILL INCLUDE, OR IS DISPOSED TO INCLUDE,
' CRITERIA FOR LEAKAGE DETECTION.
1H( STRONG INCLINATION TO REJECT LBB FOR SIZEWELL BASED ON CONCERNS WITH SCC AND NDE (CEGB AT ODDS WITH NII ON THIS).
FRANCE UNDECIDED, BUT WEAKLY INCLINED TO REJECT LBB AT THIS TIME
- PARTLY BECAUSE OF COMMITMENT TO STANDARDIZATION. RESEARCH ON LBB IN PROGRESS.
! STRONG COMMITMENT TO LBB IN PWR MAIN COOLANT, MAIN FEED AND FRG MAIN STEAM INSIDE CONTAINMENT.
ITALY CLOSE TO FRG PRACTICES.
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BROAD SCOPE GDC-4 RULE FOREIGN PRACTICES: (CONTINUED)
INCLINED TO ACCEPT LBB, HEAVY INVESTMENT IN LBB RESEARCH.
JAPAN CANADA INCLINED TO ACCEPT LBB FOR CERTAIN PIPING SYSTEMS AT THE DARLINGTON FACILITY.
' MOST OTHER COUNTRIES SEEM TO BE LESS ACTIVELY INVOLVED IN LBB, OR ARE OBSERVING DEVELOPMENTS IN THE LEADERSHIP COUNTRIES ABOVE.
i
it BROAD SCOPE GDC-4 RULE VALUE/ IMPACTS 0 FOR THE LIMTIED SCOPE RULE, APPLYING LBB TO PRIMARY COOLANT LOOP PIPING IN A FORECASTED POPULATION OF 85 PWRS LED TO THE FOLLOWING .
BEST ESTIMATE RESULTS:
34,000 MAN-REM AVERTED RADIATION EXPOSURES:
REDUCED COSTS: $186 MILLION 0 IF LBB COULD BE APPLIED TO BWR RECIRCULATION LOOP PIPING UNDER f THE BROAD SCOPE RULE, THESE QUANTITIES COULD BE INCREMENTED AS FOLLOWS (BASED ON A F0PECASTED 38 BWRS):
8,600 MAN-REM AVERTED RADIATION EXPOSURES:
REDUCED COSTS: $30 MILLION 0 FOR ANY FUTURE PLANT, COST SAVINGS OF APPROXIMATELY $90 MILLION l
i ARE ESTIMATED PER PLANT THROUGH SELECTIVE EXCLUSION OF PIPE BREAKS (DUE TO IMPROVED CONSTRUCTION SCHEDULES, REDUCTIONS IN l SOME l
FINANCING COSTS AND DIRECT DESIGN AND CONSTRUCTION COSTS).
- 0F THESE PIPE BREAKS ARE CLASSIFIED AS ARBITRARY INTERMEDIATE PIPE RUPTURES AND CAN BE EXCLUDED VIA THE REVISION TO SRP 3.6.2 CURRENTLY UNDERWAYs OTHER PIPE BREAKS DEPEND ON THIS PRESENT l
RULEMAKING.
12.
BROAD SCOPE GDC-4 RULE ACCEPTANCE CRITERIA (BASED WITH SOME REVISIONS ON CHAPTER 5, VOLUME 3, NUREG-1061) 0 LBB IS NOT APPLICABLE TO PIPING SUSCEPTIBLE TO FAILURE FROM CORROSION (FOR EXAMPLE, IGSCC).
0 8.BB IS NOT APPLICABLE TO PIPING SUSCEPTIBLE TO FAILURE FROM W HAMMER.
3 0 LBB IS NOT APPLICABLE TO PIPING SUSCEPTIBLE TO FAILURE FROM i
FATIGUE (HIGH AND LOW CYCLE THERMAL AND MECHANICAL FATIGUE).
THE PRESENCE OF MINOR CORROSION, WATER HAPMER AND FATIGUE N_QTE:
i EITHER ALONE OR IN COMBINATION DOES NOT EXCLUDE APPLICATION OF LBB. APPLICANTS AND LICENSEES MUST DEMONSTRATE THAT THESE PHENOMENA CAN BE RESISTED WITH MRGINS TO COVER
' UNCERTAINTIES IN ORDER TO TAKE ADVANTAGE OF LBB, THE BULK CORROSION OF NRC ACCEPTANCE CRITERIA DEALS WITH FATIGUE.
REQUIREMENTS CAN BE SATISFIED BY SELECTING MATERIALS l
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BROAD SCOPE GDC-4 RULE i
l ACCEPTANCE CRITERIA (CONTINUED)
WITH IMUNE TO CORROSION OR THROUGH CONTROL OF WATER CHEMISTRY.
REGARD TO WATER HAPMER, APPROXIMATELY 150 DAMAGING WATER HAPPERS HAVE OCCURRED IN THE LAST TWENTY YEARS, AND AT INDIAN POINT AND IN PIPING.
MAINE YANKEE HAVE CAUSED LARGE LEAKS (BUT NOT DEGBS)
THE STAFF HAS CONCLUDED THAT ELIMINATION OF WATER HAPMER IS N HOWEVER, PROVEN DESIGN CHANGES (J-TUBES, "KEEP-FULL" l
POSSIBLE.
j SYSTEMS AND VACUMN BREAKERS) CAN MINIMIZE THE POTENTIAL FOR APPLICANTS AND l
HAMMER AS CAN OPERATOR AWARENESS AND TRAINING.
LICENSEES CAN USE HISTORICAL INFORMATION TO DEMONSTRATE THAT WATER HA MER DOES NOT AFFECT SPECIFIC CLASSES OF PIPING SYST ALTERNATIVELY, A COPPIITENT TO DESIGN CHANGES AND IMPROVED j
- OPERATING PROCEDURES MAY SATISFY CONCERNS WITH WATER HAPPER.
! CORROSION AND WATER HAPMER HAVE NOT BEEN OBSERVED IN PWR PR COOLANT LOOPS.
l O LBB IS NOT APPLICABLE IF THERE IS A HIGH PROBABILITY OF PIPE FAILURE OR DEGRADATION FROM INDIRECT CAUSES SUCH AS FIRES, MISSILES, EQUIPPENT FAILURES OR FAILURES OF SYSTEMS AND j
COMPONENTS IN CLOSE PROXIMITY TO THE PIPE.
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BROAD SCOPE GDC-4 RULE ACCEPTANCE CRITERIA (CONTINUED) 0 THE CR?TERIA IN NUREG-1061, VOLUME 3, CHAPTER S ARE REVISED SUCH .
THAT THE CASE-BY-' CASE EVALUATION OF ENVIRONMENTAL EFFECTS IS NOT ALLOWED.
1 0 MARGINS IN PIPE SUPPORTS AND SUPPORTS OF PIPE MOUNTED COMPONENTS ARE TO BE MAINTAINED AFTER THE DYNAMIC EFFECTS OF PIPE RUPTURE ARE EXCLUDED FROM THE DESIGN BASIS.
O LBB IS NOT APPLICABLE IF REQUIREMENTS OF IEB 79-14 HAVE NOT BEEN MET (REQUIRES AS-BUILT CONFIGURATION IN STRESS ANALYSIS).
O LBB ONLY APPLICABLE IF PIPING MATERIALS NOT SUBJECT TO CLEAVAGE FRACTURE (BRITTLE FRACTURE) OVER TEMPERATURE RANGE WHERE RUPTURE HAS SERIOUS CONSEQUENCES.
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' BROAD SCOPE GDC 14 RULE ACCEPTANCE CRITERIA (CONTINUED) ~
i L
DETAILED FRACTURE MECHANICS PROCEDURE O SPECIFY LOADS AND STRESSES (TYPE, MAGNITUDE, SOURCES AND l COMBINATION METHOD). IDENTIFY LOCATION (S) WHERE HIGHEST STRESSES COINCIDENT WITH POOREST MATERIAL PROPERTIES OCCUR.
O IDENTIFY MATERIALS, THEIR SPECIFICATIONS AND PROPERTIES (TOUGHNESS AND TENSILE DATA, THERMAL AGING AND OTHER LIMITATIONS). ,
l O POSTULATE LARGEST FLAW PERMITTED BY SECTION XI AT LOCATION (S)
I ABOVE. SHOW BY FATIGUE CRACK GROWTH ANALYSIS THAT SIGNIFICANT
) GROWTH DOES NOT OCCUR. ,
O POSTULATE THROUGHWALL FLAW SIZE S0 THAT LEAKAGE IS DETECTED WITH i MARGIN UNDER NORMAL LOADS AT LOCATION (S) ABOVE.
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BROAD SCOPE GDC-4 RULE
. ACCEPTANCE CRITERIA (CONTINUED)
' DETAILED FRACTURE MECHANICS PROCEDURE (CONTINUED) 0 APPLY N+SSE LOADS TO SHOW POSTULATED IN NORMAL)
THROUGHWALL FLA (I.E., CRACK GROWTH MINIMAL FOR LONG PERIOD).
0 APPLY N+SSE LOADS TO SHOW A MARGIN GREATER THAN 2 BETWEE POSTULATED THROUGHWALL FLAW AND CRITICAL SIZE CRACK.
O SHOW THAT POSTULATED THROUGHWALL FLAWS ARE STABLE IN TE CRACK GROWTH WHEN APPLYING LOADS 1.4 TIMES N+SSE LOADS.
! O J-R AND TENSILE CURVES SHOULD BE PROVIDED FOR TEMPERAT UPPER RANGE OF NORMAL OPERATION AND SHOULD SHOW DUCTIL t_________ __ _ ______ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _---_- - _ --- _ _
O "
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BROAD SCOPE EDC-4 RULE ,
ACCEPTANCE CRITERIA (CONTINUED)
DETAILED FRACTURE MECHANICS PROCEDURE (CONTINUED) 0 IDEALLY, J-R CURVES OBTAINED FROM SPECIMEN THICKNESSES GREATER l l
THAN PIPE WALL.
- SPECIMEN SIZED TO OBTAIN CRACK EXTENSIONS CONSISTEN J/T CONDITION.
- IF SPECIMEN SIZE LIMITATIONS EXIST, EXTRAPOLATION IF '
APPROPRIATE, MAY BE USED.
O PROVIDE TENSILE CURVES FROM PROPORTIONAL LIMIT TO MAX LOAD.
~
l 0 IDEALLY, MATERIALS TESTS (BOTH BASE AND WELD METALS) SHOULD BE IF ARCHIVAL MATERIAL CONDUCTED USING ARCHIVAL MATERIAL.
UNAVAILABLE, SUBSTITUTE SPECIENS FROM 3 HEATS HAVING SAME MATERIAL SPECIFICATION.
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, it BROAD SCOPE GDC-4 RULE ACCEPTANCE CRITERIA (CONTINUED)
DETAILED FRACTURE MECHANICS PROCEDURE (CONTINUED) 0 TWO TENSILE AND J-R CURVES SHOULD BE OBTAINED FROM EACH OF 3 HEATS WITH SAME MATERIAL SPECIFICATIONS, THERMAL AND FABRICATION HISTORIES AS PIPING MATERIAL.
- FROM ARCHIVAL MATERIAL, 3 TENSILE AND J-R CURVES IS SUFFICIENT.
TESTING TEMPERATURES SHOULD BE NEAR UPPER RANGE OF NORMAL OPERATION (E.G., 5500 F).
ONE TENSILE AND J-R CURVE SHOULD BE OBTAINED AT LOWER TEMPERATURE (E.G., HOT STANDBY) TO DETERMINE DEPENDENCE OF i
TOUGHNESS ON TEMPERATURE.
O SUBJECT TO GENERIC RESTRICTIONS, LIMIT LOAD ANALYSIS ACCEPTABLE IF LIMIT MOMENT GREATER THAN 3 TIMES N+SSE MOMENT.
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W.
L BROAD SCOPE GDC-4 RULE ACCEPTANCE CRITERIA (CONTINUED) 0 LEAKAGE DETECTION SYSTEMS SHOULD BE SUFFICIENTLY RELIABLE, REDUNDANT, DIVERSE AND SENSITIVE S0 THAT A MARGIN GREATER THAN 10 ON DETECTION OF UNIDENTIFIED LEAKAGE FROM THROUGHWALL FLAW EXISTS.
O RESIDUAL WELDING STRESSES AND COLD SPRINGING STRESSES ON A CASE-BY-CASE BASIS MAY REQUIRE SPECIAL REMEDIES, AS FOR EXAMPLE, IHSI.
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l BROAD SCOPE GDC-4 RULE NRC RESOURCE DEMANDS 0 GE (FOR GESSAR) AND DUQUESNE LIGHT CO. (FOR BEAVER VALLEY, UNIT
- 2) ARE ALREADY MAKING DEMANDS FOR NRC RESOURCES UNDER THE BRO SCOPE RULE. ,
O IT IS EXPECTED THAT IF THE BROAD SCOPE RULE IS NOT PUBLISHED T ;
COMISSION WILL BE INUNDATED WITH REQUESTS FOR SYSTEM AND PL UNIQUE EXEMPTIONS TO GDC-4 IN ADDITION TO PETITIONS FOR RULEMAKING. THIS EXPECTATION ARISES BECAUSE THE PIPING REVIEW CO MITTEE PUBLICALLY SUPPORTED A BROAD SCOPE RULE AND THE LIMITIED SCOPE RULE STATED THAT "THE COMISSION WILL PROPOSE A TWO-THIRDS OF COMENTERS ON THE BROADER AMENDMENT TO GDC-4".
l
> LIMITED SCOPE RULE URGED THAT THE BROADER RULE BE EXPEDITED.
O APPROXIMATELY TEN TO TWENTY NRC MAN YEARS OF EFFORT PLUS j ADDITIONAL RESEARCH OVER THE NEXT SEVERAL YEARS ARE ESTIMATED J RESPOND TO INDUSTRY INITIATIVES TAKEN UNDER THE BROAD SCOPE RULE '
NOTE: INDUSTRY HAS ALREADY EXPENDED AND IS CONTINUING TO EXPEND l ' CONSIDERABLE RESOURCES FOR LBB RESEARCH, ANALYTICAL TECHNIOUES AND CRITERIA DEVELOPMENT. ,
. 11 BROAD SCOPE GDC-4 RULE RELATED NRC REGULATORY ACTIONS SRP 3.6.2 IS F,EING REVISED TO ELIMINATE REQUIREMENTS FOR ARBITRARY INTERMEDIATE PIPE BREAKS. THIS REVISION WILL ALSO ALLOW THE REMOVAL 0F PIPE WHIP RESTRAINTS AND JET IMPINGEMENT BARRIERS, BUT IS HOWEVER, THE SRP REVISION HAS ABOUT INDEPENDENT OF THIS RULEMAKING.
THE PIPE RUPTURES THE SAME POTENTIAL MAGNITUDE OF VALUE/ IMPACTS.
BEING ELIMINATED VIA THE SRP REVISION ARE:
- 1. ARBITRARY IN THE SENSE THAT THEY ARE REQUIRED WITHOUT PHENOMEN0 LOGICAL BASES, THAT IS, EVEN THOUGH STRESSES AND USAGE FACTORS (A FATIGUE MEASURE) ARE ACCEPTABLY LOW, THESE BREAKS ARE STILL POSTULATED.
- 2. INTERMEDIATE TO CONTRAST WITH TERMINAL END BREAKS WHICH ARE S POSTULATED. TERMINAL END BREAKS ARE POSTULATED WITHOUT SPECIFIED PHENOMEN0 LOGICAL BASES BECAUSE HISTORY TEACHES THAT PIPE RUPTUR ARE MORE LIKELY TO OCCUR AT TERMINAL ENDS. '
-_A L .- -
BROAD SCOPE GDC-4 RULE RELATED NRC REGULATORY ACTIONS (CONTINUED) .
THIS RULEMAKING AFFECTS POSTULATED BREAKS WHICH ARE ffDT NORMALLY ARBITRARY INTERMEDIATE BREAKS. ABOUT FIFTEEN NUCLEAR POWER UNITS HAVE ALREADY BEEN ALLOWED TO RELAX ARBITRARY INTERMEDIATE BREAK REQUIREMENTS EVEN THOUGH THE REVISION IS STILL IN PROGRESS.
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i Enclosure 2 to the Minutes of CRGR Meeting No. 98 Review of Proposed Rule Change to 10 CFR 20 for Personnel Dosimetry Processor Accreditation K. Goller (RES) presented for CRGR review a proposed revision to the NRC regulations on personnel monitoring in 10 CFR Part 20 to require NRC licensees to use personnel dosimetry processors that are accredited under the National Voluntary Laboratory Accreditation Program (NVLAP). The NVLAP program is operated by the National Bureau of Standards (Department of Coninerce). A copy of their presentation is attached.
To date, there are no specific regulatory requirements (perfonnance standards) for personnel dosimetry processing, even though accurate and consistent measurements are directly related to the ability of the licensees to conform to NRC regulations in 10 CFR 20. Recognizing this, three rounds of proficiency testing of processors were sponsored by the NRC. Acceptance criteria was based on Health Physics Society Standards. The results indicated that improvements in processing were warranted, and that measurable improvement could be expected by requiring the processors to be certified by NVLAP. In this regard, a proposed rule was published in 1984. The CRGR was requested at Meeting No. 98 to recomend in favor of issuing the final rule.
A number of major points were discussed at the meeting:
- 1. It is not clear how much control the NRC has over the NVLAP program.
Although there is an NRC staff member on the NVLAP certificatico board, it was concluded that the NRC has no direct / specific control over NVLAP. i However, it was noted that in general, the existing memorandum of l understanding between the NRC and the Department of Comerce allows the l NRC to veto major changes in the NVLAP program.
- 2. How would the backfit provisions of 10 CFR 50.109 be applied? NVLAP certification is based on ANSI Standard N13.11, which would most likely not be reviewed against 10 CFR 50.109. Who would review changes to the standard? While CRGR believes that the NRC is relinquishing some control, the Comittee concluded this might result in industry dedication to improving dosimetry in general. The concern reall proposed mechanism to review changes (backfitting)y . RES is anrequested was absencetoof a consider whether any changes in the proposed rule were warranted with l respect to improving control of backfitting. '
- a. Page 19 of Enclosure C, Analysis of Coninents, indicates that NRC cannot oversee the quality control aspects of dosimetry processing due to personnel limitations. Staffing is not really the issue, it is simply a question of priorities. NRC can, and will, continue to review dosimetry processors on a sampling basis.
- b. Page 30/31 of Enclosure C Analysis of Comments, indicates that NRC will issue supplementary information. The package should indicate what type of guidance will be issued and in what form (i.e.,
Regulatory Guide, staff positions, etc.).
- 4. The issue of best available control technology was discussed; i.e., is 230 percent simply the best we can do? It appears that this is the case.
However, the rule change would not help in eliminating other sources of error, such as TLD placement, overage by tape, etc.
- 5. RES emphasized that the proposed rule change would only save occupational exposure in an indirect fashion. If industry was reporting dose as 11,000 man-rem different than what is perceived to be the actual dose, industry likely will take steps to eliminate this apparent inaccurar.y and thereby utilize the information in the ALARA program to reduce exposure. Further, reported dose likely will have a net reduction due to more accurate reporting. .
- 6. Due to the cost of certification, as many as ten small businesses may decide not to continue supplying dosimeters. These businesses could possibly be given an option or alternate equivalent method of becoming certified. It was decided that the discussion on small business irnict as ir,cluded in the original package was adequate.
- 7. CRGR questioned whether NVLAP certification was the best way to achieve the improvement in dosimetry processing. An alternative approach might be to issue a rule that states dosimetry processors must satisfy the 30 percent acceptance criteria around the NBS value as stated in Health Physics Society Standards. This, however, was seen as too prescriptive, and might lead to multiple rule changes whenaver industry standards <
change. '
On the basis of their review of the proposed rule change and the discussion at I
this meeting, the Committee recommended that the rule change be issued, subject !
to the changes in the package as noted above.
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BRIEFING FOR CRGR i
FINAL RLE TO AlBD 10 TR 20.202 PERS0MEL DDSIETRY PRD&SSOR ACCEDITATION I
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PEW EQJIRRENT ALL lEC LICENSEES WOLLD BE ROUIRED TO USE IN-HOUSE OR COTERCIAL DOSIETRY PROCESSORS ACCREDITED BY NBS (NVLAP) FOR PROCESSING THOSE PERSOPN1 D0SIETERS (EADGES) USED 10 SATISFY EGLLATIONS OR LICENSE EQUIR&DRS TO DETERMIE OCCLPATIONAL W10LE BODY DOSES.
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PERSONNEL D0SIMETRY PROCESSOR ACCREDITATION ,
BACKGROUND ,
o REGULATIONS REQUIRE MONITORING FOR NEUTR0NS, BETA PARTICLES, HIGH AND LOW ENERGY PHOTONS o NUMEROUS STUDIES BEGINNING IN 1955 SHOWED POOR PERFORMANCE OF MANY PROCESSORS EXCESSIVE BIAS AND VARIANCE DIFFICULTY MEASURING DOSES FROM LOW ENERGY PHOTONS DIFFICULTY MEASURING NEUTRONS o NRC CONTRACTED WITH UNIVERSITY OF MICHIGAN TO TEST PERSONNEL DOSIMETRY PROCES$0RS AGAINST A DRAFT CONCENSUS PERFORMANCE STANDARD (1977-1982);
LESS THAN 50% OF THE INITIAL TESTS WERE PASSED o THEREFORE, NRC PUBLISHED ANPRM REGARDING NEED FOR MANDATORY TESTING /
ACCREDITATION PROGRAM (1980) o COMMENT 0RS EXPRESSED PREFERENCE FOR FEDERAL GOVERNMENT PROGRAM 9
3
PERSONNEL DOSIMETRY PROCESSOR ACCREDITATION (CONTINUED) o NRC REQUESTED THAT NBS ESTABLISH AN ACCREDITATION PROGRAM AND PROVIDED SEED MONEY (1980)
PROGRAM STARTED IN JANUARY 1984 54 0F 90 KNOWN PROCESSORS ARE CURRENTLY IN PROGRAM '
45 ARE ACCREDITED: 9 ARE UNDER REVIEW o NRC PUBLISHED A PROPOSED RULE THAT WOULD REQUIRE THE USE OF NBS (NVLAP)
ACCREDITED D0SIMETRY PROCESSORS (JAN 1984)'
o NINETY-TilREE COMMENT LETTERS RECEIVED, 80% IN FAVOR OF RULE o FINAL RULE DIFFERS FROM PROPOSED RULE BY ONLY A MINOR CHANGE (REQUIREMENT FOR LICENSEES TO HAVE COPY OF THEIR PROCESSOR'S ACCREDITATION CERTIFICATE WAS DELETED) o SUCCESS OF NBS NVLAP PROGRAM ATTRIBUTED TO PROSPECT OF NRC FINAL RULE t
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COST trttcilVEESS OF RULE ,
~
o FIRST PROFIC;ENCY TEST SHOWED:
LESS THAN 50% OF TEST CATEGORIES EE PASSED PUST M O FAILED DID SO BY FACIDRS OF 2 TD 4. S0E AS HIGI AS 2000 UNDEESTIMATES AND OVEESTIMTES EE ABOUT EDUALLY DISTRIBUTED o AS A FIRST APPR0XIMATION:
25% OF ECORDED DOSES EE LOW BY FACTDR OF 3 25% OF ECORDED DOSES WEE HIGi BY FACTOR OF 3 o APPLICATION OF THESE ESTIMATES TO 1982 fFP WORKER ECORDS (CONSIDERING ONLY A!HJAL DOSES ABOVE 2 REMS) SHOWS:
11,000 PERSON MS ECEIVED BUT NOT ECORDED; Ur0ER RULE, EWLOYEPS WOULD PROBABLY HAVE REDUCED IPDIVIDUAL DOSES CLOSE TO PEVIOUS LEVELS, WITH A COLLECTIVE-DOSE REDUCTION APPROA0ilNG 11,000 PERSONREPS 3700 PERSON PBS ECORDED BUT NOT ECEIVED; LF0ER RULE, EWLOYERS MIGif HAVE ALLOWED ADDITIONAL EXPOSURE FOR CERTAIN SKILLED WORKERS; EFECT ON COLLECTIVE DOSE WOULD HAVE BEEN SMALL o LARGE FRACTION OF THIS COLLECTIVE DOSE COLLD HAVE BEEN ELIMINARD BY REDUCING DOSE LKERTAINTIES THROUGH ACCEDITATION o BASED ON EALTH trrttis COSTS ALOE, ACCREDITATION N0lLD HAVE SAVED 'JP TO $7,000.000 AS (IPPAED TO ACCEDITATION PROGRAM COSIS OF ABOUT $630,000 FOR TE 75 OPERATING PLANTS IN 1982 5
SlESTANTIAL IPPROVE?ENT IN SAFEIY ,
o BASED ON ANALYSIS OF 1982 DOSE ECORDS, ACCREDITATION COULD HAVE:
PREVENTED ACTUAL OVEEXPOSURES OF 175 IEIVIDUALS PEVENTED POSSIBLE OVEREXPOSURES OF AWTEP.1685 IEIVIDUALS PREVENTED A fBN lNREPORTED EXPOSURE OF 5.9 REMS TO EACH OF 1,860 INDIVIDUALS PREVENTED AN UNREPORTED EXF0SURE OF 11,090 PERSON REPS TO THOSE ECEIVING DOSES ABOVE 2 REMS e
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PERTIENT FACTS ,
O PEVIOUS VOLINTARY ACCEDITATION PROGRAM WAS EVER SUCCtsSFUL o 1.4 MILLION USA WORKERS E0 VIE RADIATION P0NITORING (AB0lff 25% WORK FOR NRC LICENSEES)
O CONTRCIAL DOSIKTRY PROCESSIfE BUSIESS IS HIGHLY COPPETITIVE (ESTIPATEI) TO BE
$34 MILLION Aff4] ALLY) o WELL-QJALIFIED FIRMS C&PETE AGAINST THOSE LESS QJALIFIED ASSlWTIONS o CUSTWERS OFTEN HAVE LITTLE EXPERTISE IN DOSIETRY PROCESSING; GEERALLY C0hTRACT.T0 LOWEST BIDDER o LESS-0UALIFIED FIRMS OFIEN fEGLECT TEOMICAL #0 OPERATIONAL DETAILS TO KEEP PRICES LOW o WELL-QJALIFIED FIRMS SOETIPES REDUCE TIE QJA!.ITY OF TEIR PROCESSING PERFOMANCE TO REMAIN CCrttitlIVE 7
... . - . _ _ . __m _. - - ,_ _ .- .- . _.. _ _ _ . . . . - - --_ . . _
PM&SSOR CATEGORIES -
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MMUA'. COST TOTAL LARGE LARGE COPPERCIAL 7 LARGE PRIVATE 7 NUCLEAR POWER PLARIS 31 45 $8375.00 $376,US INTEREDIATE 1
l NATIONAL LABORATORIES 9 UNIVERSITIES #0 PEDICAL 4 P!ILITARY 8 DOE CONTRACTORS J_0 31 $5700.00 $176,700 SMALL '
STATE EALTH DEPARIPENTS 4 SMALL BUSIESS 10 '
14 $2850.00 $ 39,900 -
GRAl0 TOTAL $593,475 !-
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A Enclosure 3 to the Minutes of CRGR Meeting No. 82 Review of Proposed IE Bulletin Hoter-Operated Value (Mov) comon Mode Failures During Plant Transients Due to Improper Switch Settings E. Rossi, H. Bailey and R. Kiessel (IE) presented for CRGR review the subject proposed IE Bulletin. Issuance of the bulletin was proposed by the staff in response to two recent failures of MOVs in operating plants (i.e., Davis-Basse and Sequoyah), and a history of similar problems with MOVs in operating plants over the years despite a nunter of regulatory actions taken previously to address such problems. The proposed bulletin specifies actions to be taken by all licensees /permittees, intended to better assure that the switch settings on MOV operaters are selected, set and maintained correctly so that MOVs will operate properly upon demand over the entire range of differential pressures that might be experienced across the valves during both nonnal operation and abnonnal events within the design basis of the plant. Special emphasis was given in the actions prescribed in the proposed bulletin, to testing of MOVs under the highest differential pressure that might reasonably be expected to occur within the design basis, as a means of demonstrating needed operability and reliability characteristics.
The package submitted by IE to CRGR for review was transmitted by memorandum dated October 4,1985. J. M. Taylor to V. Stello, Jr.; the package included the following documents:
- 1. Proposed Bulletin, undated, entitled "Motor-Operated Yalve Comon Mode Failures During Plant Transients Due to improper Switch Settings," and
Attachment:
- a. "Table ! - Sumary of Significant MOV Abnormalities Identified by MOVATS"
- 2. Information Required for CRGR Review (in accordance with provisions of ,
Section IV.B of the CRGR Charter).
- 3. Cost-Benefit Analysis for Proposed Bulletin 4 Proposed Temporary Instruction, "Initial Inspection Requirements for )
(proposed) IE Bulletin...", and Attachments: I
- a. Appendix !!, "Temporary Instruction, Supplement 1"
- b. Appendix III, "Temporary Instruction, Supplement 2" l
Other documents provided for infomation to CRGR by ROGR staff in connection with the Comittee's review of this item were:
- 1. Memorandum, dated September 20, 1985, C. R. Norelius, Region !!!, to E. L. Jordan, IE, entitled "Proposed IE Bulletin: Motor-Operated Failurc-During Plant Transients Due To Improper Switch Settings" (transmitting detailed coments - Attachment 1 to this enclosure).
- 2. Letter, dated September 6,1985, R. A. Szalay AIF to C. E. Rossi, IE, regarding "!E Oraf t Bulletin: Motor-Operated Valve Faiiures During Plant Transients due to Improper Switch Settings."
Copies of the slides used for this presentation by IE to sumarize the :
background and specific catent of this bulletin and to focus discussions at this meeting are attached (see Attachments 1 and 2 to this enclosure).
The proposed bulletin focused on MOVs in the emergency feedwater and high pressure injection or core spray systems. Detailed actions specified with respect to these systems / valves include: ,
- 1. For each plant, review (and revise, as necessary) the design basis for operation of MOVs in the specified systems to determine the differential pressures that are expected to occur across those valves during normal operation or any abnonnal event within the design basis of the plant;
- 2. Given the results of (1), review (and revise, as necessary) the methods used to select, set, and maintain proper MOV operation switch settings (specifically, the settings for valve operator torque, torque bypass, '
valve position limits, and overload) to assure that valves will operate properly upon demand under all conditions that are expected to occur within the design basis. (Thisshouldincludespecificallytestingthe operability of the MOVs involved under the highest differential pressures that would be experienced across the valves during nomal operation or any abnonnal event within the design basis of the plant).
- 3. Prepare or revise procedures to assure that correct MOV switch settings '
are maintained throughout the life of the plant.
- 4. Within 120 days after the date of issuance of the proposed bulletin, submit to NRC a report that describes the licensee's/pemitee's erogram to accomplish the above actions and the schedule for completion of aose ,
actions (not to exceed 2 years from the date of the bullet') '
- 5. Within 60 days af ter completion of all the above, provide to NRC a written report to include the following:
- a. Verification of completion of the actions specified above-
- b. A sumary of findings with respect to pretest and post-test MOV switch settings and operability (to be used by NRC in the resolution !
of generic issue !!.E.6) !
The staff estimated that, conservatively, a reduction in core melt probability of 1.0 E(-6)/ reactor-year could be achieved as a result of implementing the 1
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I proposed bulletin. Considering 134 plants with an estimated average life of about 28 years, this would equcte to 1.2 E(4) person-rems averted public and occupational dose benefit. Using a conversion factor of $1,000/ person-rem, the total benefit expected by the staff to be gained by implementing the proposed bulletin is $12 million. The total cost of implementing this bulletin was i estimated by the staff to be $2.2 million; that figure included (a) the dollar value (i.e. $600K) of 558 person-rems additional occupational exposure expected to accrue in the testing of approximately 20 valves / plants in contaminated systems (b) $270K estimated cost of NRC review of licensees' responses to the bulletin, and (c) $7.6 million negative cost due to averted properly damage and clean up expenses expected to result from improvement of core melt frequency. The staff estimate for the time required reasonably to complete all actions specified in the proposed bulletin was about 2 years, 1
There was much discussion of the term "within the design basis *' used in the proposed bulletin and what was intended by,the staff in prescribing tests of I MOVs under the highest differential pressures expected to occur "within the
- design basis." Specific questions examined in some detail were the following
(a) Did the staff intend a review by licensees of the _ existing, approved design basis for their facilities (to establish the differential pressures that MOVs might experience), or did the staff really intend by this bulletin to catend the existing, approved design basis for all facilities to include /acconnodate the specific sequence and combination of equipment and operator features that occurred on June 9 at Davis-Besse?
(b) Did the staff really intend to specify testing of MOVs under the highest differential pressures that could be experienced in connection with any conditions within the design basis, including large pipe breaks?
The Comittee noted that the June 9 event at Davis Pre was cited prominently
- in the discussion of background for issuing the buP e ,in; ard tht.i; background 1
discussion was juxtaposed in the proposed bulletin e 4th a requirement for a I
comprehensive conditions (specifically,review of the flows and desi;n basis differential of eachunder pressures operating) which MOVs plant, to detemine might be expected to be called upon to operate. That juxtaposition in the
] proposed bulletin, without any explicit added statement that the combination of features in the June 9 was outside the existing, approved design basis for Davis-Besse, carried with it the suggestion that the staff thought it necessary for all operating nuclear plants to be able to accennodate that particular sequence of events / failures, and that the proposed bulletin was the vehicle intended to accomplish this. The same suggestion came through in remarks by
- some staff members in discussions at details of the proposed bulletin with the i CRGR at this meeting. The Connittee asked the staff to clarify its intention i
(and the wording of the proposed bulletin) in this regard, noting that if the l l
staff intended an expansion of the existing design basis it did not appear that '
adequate justification for such a generic measure had been offered in the l review package. '
- l Af ter discussion of these points the staff agreed that the wording of the l proposed bulletin should be modified to state explicitly that licensees /
pemittees should review carefully their existing, approved design bases 1
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(i.e., analyses and assumptions documented previously in licensees' FSAR analyses, operating and emergency procedures, etc., and accepted on the basis of the normal staff review process for licensino) as a means of establishing the differential pressures and other conditions under which MOVs should be able to operate, and as the basis for deciding what tests should be applied to MOVs to demonstrate the capability to operate under those conditions. The staff will then determine, on the basis of review of the licensees' bulletin responses whether there is the need to redefine or extend the existing design basis for any licensee's facility, and/or whether the specific MOV tests proposed by licensees are adequate to demonstrate suitable operability within whatever design basis the staff decides is appropriate. With regard to the question of licensees considering large pipe breaks (and the differential pressures that could accompany them) in their design basis analyses, the staff indicated that the wording of the bulletin will be revised to include the consideratior, of pipe breaks in the design basis reviews specified, but exclude actual testing of MOVs under pipe break conditions.
The question of whether or not the actions specified in the proposed bulletin constituted backfitting and, if so, whether such backfitting was justified in view of the cost-benefit analysis provided by staff, was discussed in some detail. It was noted that the incremental benefit of the proposed action projected by the staff was quite small; but it was also acknowledged that, if better methods were available for taking fully into account comon mode effects in such analyses, the projected benefit outlook would likely be significantly improved. The question was made somewhat moot, however, by the staff's clarification of its intent with regard to the "design basis" question i addressed above. it was agreed that, if the actions specified in the bulletin were clearly directed only to correction of deficiencies in meeting the existing, approved design basis (as would be made clear by revising the wording of the bulletin), then no backfitting was involved and the proposed actions did not have to be justified on the basis of cost-benefit.
As a result of the discussions at this meeting, the Corsnittee reconsnended that the proposed bulletin be issued, subject to incorporation of the revisions i
indicated in the preceding. IE agreed to coordinate the necessary revisions i with ROGR staff prior to the issuance of the bulletin.
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) ilENRY BAILEY, IE l I
) NICHARD KIESSEL, IE i l
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TITLE: PROPOSED lE BULLETIN 85-XX, HOTOR-OPERATED VALVE COMMON MODE FAILURES DURING PLANT TRANSIENTS DUE TO IMPROPER SWITCH SETTINGS.
PURPOSE:
REQUEST LICENSEES TO DEVELOP AND IMPLEMENT PROGRAM TO ENSURE SWITCHES ON AUXILIARY FEEDWATER AND HIGH PRESSURE INJECTION / CORE SPRAY MOTOR-OPERATEL VALVES ARE SET AND MAINTAINED PROPERLY TO ACCOMODATE THE HIGHEST DIFFERENTIAL PRESSURE WITHIN THE DESIGN BASIS.
ADDITIONAL OBJECTIVE: TO ENCOURAG.i THE INDUSTRY TO DEVELOP IMPROVED PROGRAMS FOR ENSURING VALVE OPERABlLlTY.
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l ORDER OF PRESENTATION l
- 1. DESCRIPTION OF A LIMITORQUE VALVE-OPERATOR i
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- 2. DAVIS BESSE LOSS OF MAIN AND AUXlLIARY FEEDWATER, OF JUNE 9, 1985
- 3. EXAMPLES OF OTHER MOTOR-OPERATED VALVE SWITCH PROBLEMS l l
- 4. ACTIONS REQUIRED BY PROPOSED BULLETIN 1
- 5. COST-BENEFIT ANALYSIS
- 6. INPO ACTIVITIES l 1
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BASIC PRINCIPLE OF OPERATION i
L. Switch Assembly Torque Switches q
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Splined Shaf t O,h Worm Gear Legs to Valve Stem Rotate Stem Nur Stem Nut
DAVIS BESSE LOSS OF MAIN AND AUXILIARY FEEDWATER, JUNE 9, 1985 OPERATOR INADVERTENTLY CLOSED AFW ISOLATION VALVES BOTH MOTOR-OPERATED AFW VALVES FAl LED TO REOPEN AFW VALVES WERE OPENED BY HANDWHEELS DURING RECOVERY FROM EVENT FAILURES CAUSED BY IMPROPER SETTING OF TORQUE BYPASS SWITCH METHODS FOR; (1) SELECTING SETPOINT AND; (2) SETTING l TORQUE BYPASS SWITCHES WERE DEFECTIVE l
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l EXAMPLES OF OTHER MOTOR-OPERATED VALVE SWITCH PROBLEMS
- 1. PILGRIM, MARCH 31, 1982 1
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HPCI SYSTEM VALVE FAILED TO OPEN. INVESTIGATION SHOVED THIS l VALVE OPERATOR AND NINE OTHER VALVES IN THE HPCl, CORE SPRAY AND CONTAINMENT SPRAY SYSTEMS DlD NOT HAVE TORQUE BYPASS j SWITCHES INSTALLED. THIS EVENT OCCURRED APPROXIMATELY SIX MONTHS AFTER lE CIRCULAR 81-13 HAD IDENTIFIED THE SAME PROBLEM AT BRUNSWICK 2 AND COOPER. THE CURRENT INSERVICE TESTING REQUIREMENTS NORMALLY WILL NOT DETECT THE, LACK OF A TORQUE BYPASS CIRCUIT.
- 2. SAN ONOFRE UNIT 1, SEPTEMBER 3, 1981 SAFETY INJECTION VALVES IN BOTH TRAINS FAILED TO OPEN WHEN CHALLENGED UNDER AN ACTUAL SI SIGNAL. IMPROPERLY SET VALVE OPERATOR TORQUE AND TORQUE BYPASS SWITCHES WERE THE CAUSE OF THIS FAILURE.
- 3. TROJAN, OCTOBER 28, 1976 '
l TWO VALVES IN THE CHARGING PUMP SUCTION FAILED TO OPEN IN RESPONSE TO A SPURIOUS SAFETY INJECTION SIGNAL. THE CAUSE l WAS FOUND TO BE IMPROPERLY ADJUSTED TORQUE BYPASS SWITCHES.
- 4. SEQUOYAH UNIT 2, MAY 2, 1985 TWO MFW ISOLATION VALVE STEMS SHEARED FROM THEIR DISCS. IN-CORRECT VALVE-WIDE-OPEN LIMIT SWITCH SETTINGS WERE THE CAUSE.
- 5. NORTH ANNA UNITS 162, JULY 22, 1984 BASED ON NRC RESIDENT INSPECTOR CONCERNS, INSPECTIONS OF VALVE OPERATORS WERE COMPLETED ON UNITS IS2. 67 OF 134 VALVE OPERATORS ON UNIT 1 AND 62 OF 138 VALVE OPERATORS ON UNIT 2 WERE FOUND TO HAVE TORQUE SWITCH SETTINGS THAT WERE NOT WITHIN THE LIMITS SPECIFIED BY PROCEDURE.
- 6. OYSTER CREEK, JANUARY 5, 1984 GPU REPORTED IN LER 83-024 THAT A NUMBER OF TORQUE SWITCHES WERE SET BELOW THE MANUFACTURER'S RECOMMENDED VALUES AND WERE SET EVEN LOWER THAN THE SETPOINTS USED DURING PREOPERA-TIONAL TESTING. DURING THIS REVIEW, GPU DISCOVERED THAT NO FORMAL SETPOINT REQUIREMENTS FOR TORQUE SWITCH SETTINGS EXISTED. j
- 7. H. B. ROBINSON 2, JULY 30, 1982 WHILE IN HOT SHUTDOWN, OPERATORS TRIED UNSUCCESSFULLY TO '
REMOTELY CLOSE THE PORV BLOCK VALVES. ONE VALVE WAS THEN CLOSED MANUALLY. THE MOTOR-OPERATOR WAS USED TO UNSEAT THE SECOND VALVE FROM THE BACKSEAT. WHEN THE CLOSED POSITION WAS REACHED, THE MOTOR CONTINUED TO APPLY TORQUE ,
CAUSING THREE OF THE FOUR YOKE-TO-BONNET BOLTS TO BREAK. i THE TORQUE SWITCH WAS FOUND TO BE INOPERABLE.
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- 8. OCONEE 2, SEPTEMBER 18, 1981 DURING A COOLDOWN TO STOP A SG TUBE LEAK, A 12 INCH MOV IN THE SINGLE DECAY HEAT SUCTION LINE FAILED TO OPEN UPON DEMAND.
THE OPERATOR WAS REMOVED AND THE VALVE WAS OPENED WITH A HOIST AFTER A 17 HOUR DELAY. AN IMPROPERLY ADJUSTED TORQUE SWITCH IS BELIEVED TO HAVE CAUSED OR CONTRIBUTED TO THis FAILURE.
- 9. COOPER, DECEMBER 1980 RHR INJECTION VALVE FAILED TO OPEN. BOTH TRAIN A AND TRAIN B TORQUE BYPASS SWTICHES FOUND NOT TO BE INSTALLED.
- 10. BRUNSWICK 2, SEPTEMBER 1980 RCIC INJECTION VALVE FAILED TO OPEN. TORQUE BYPASS SWITCH WAS NOT INSTALLED. FOUR OTHER RCIC VALVES FOUND NOT TO HAVE TORQUE BYPASS SWITCHES.
- 11. CRYSTAL RIVER 3, FEBRUARY 3, 1977 '
i TWO DECAY HEAT REMOVAL VALVES WOULD NOT OPEN REMOTELY DURING PLANT COOLDOWN. THE VALVES WERE OPENED BY HAND AND THE TORQUE SWITCHES WERE RESET.
- 12. CRYSTAL RIVER 3, FEBRUARY 3,1977 I
TWO DECAY HEAT REMOVAL VALVES WOULD NOT OPEN REMOTELY DURING PLANT COOLDOWN. THE VALVES WERE OPENED BY HAND AND THE TORQUE SWITCHES WERE RESET. '
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ACTIONS REQUIRED BY PROPOSED BULLETIN l A.
REVIEW AND REVISE AS NECESSARY THE DESIGN BASIS FOR MOTOR- i OPERATED VALVE OPERATION IN AFW AND HPl (RCIC FOR BWR)
SYSTEMS.
B.
REVIEW AND REVISE AS NECESSARY THE METHODS FOR SELECTING'AND SETTING SWITCHES. ESTABLISH THE CORRECT SWITCH SETTINGS FOR THE ABOVE VALVES.
C.
TEST THE ABOVE VALVES WITH THE SETTINGS FROM ITEM B AND WITH THE LARGEST DIFFERENTI AL PRESSURE DETERMINED FROM ITEM A.
ALTERNATIVES TO TESTING CAN BE USED WHERE APPROPRIATELY JUSTIFIED.
D.
PREPARE OR REVISE PROCEDURES AS NECESSARY TO ENSURE THE SETTINGS FROM ITEM B ARE MAINTAINED DURING PLANT LIFE.
E. WITHIN 120 DAYS, PROVIDE A WRITTEN DESCRIPTION OF THE PROGRAM TO COMPLETE ITEMS A THROUGH D.
WITHIN 2 YEARS, PLANTS WITH AN O. L. SHALL IMPLEMENT THIS PROGRAM.
FOR PLxNTS WITH A C. P., THE PROGRAM SHALL BE IMPLEMENTED WITHIN 2 YEARS OR ISSUANCE OF AN O.L., WHICHEVER IS LATER. t 1
F. PROVIDE A WRITTEN REPORT UPON COMPLETION OF THE PROGRAM.
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THE REPORT WILL BE USED IN RESOLUTION OF GENERIC ISSUE !
II.E.6.1.
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l COST-BENEFIT ANALYSIS CORE MELT REDUCTION l
l PRA SHOWS THE REDUCTION IN RANDOM Slf!GLE FAILURES (WITHOUT COMMON MODE CONSIDERATION) WOULD REDUCE CORE MELT FREQUENCY APPROXIMATELY 1.0 E-6 PER REACTOR-YEAR.
BENEFITS PUBLIC DOSE BENEFIT IS 2.3 PERSON-REM / REACTOR-YEAR. TOTAL PUBLIC' DOSE BENEFIT IS 1.2E4 PERSON-REM.
OCCUPATIONAL DOSE BENEFIT IS .02 PERSON-REM / REACTOR-YEAR.
TOTAL OCCUPATIONAL DOSE BENEFIT ls 80 PERSON-REM.
TOTAL DOSE BENEFIT, ($1000/ PERSON-REM), IS 12 MILLION DOLLARS.
COST INDUSTRY COST IS BASED ON 20 VALVES PER PLANT TESTED AND 24 PERSON-HRS / VALVE INITI ALLY AND 1 PERSON - HR/ VALVE / YEAR FOLLOW-ON.
INDUSTRY COST (1985 DOLLARS):
OCCUPATIONAL DOSE COST IS 600K DOLLARS.
LABOR COST IS 5.1 MI LLION DOLLARS.
ONSITE PROPERTY DAMAGE NEGATIVE COST IS 3.8 MILLION DOLLARS.
TOTAL INDUSTRY COST I S 1. 9 M I LL I ON DOLLARS .
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-2 NRC COST (1985 DOLLARS):
OCCUPATIONAL COST IS ZERO DOLLARS.
LABOR COST IS $270K DOLLARS, BASED ON 2 PERSON-HRS / VALVE INITI ALLY WITH NO FOLLOW-ON REQUIRED.
TOTAL COST, INDUSTRY AND NRC I S 2. 2 M I LLION DOLLARS.
BENEFIT-COST RATIO IS 5.5.
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INPO ACTIVITIES INPO REPORT 83-037, "ASSESSMENT OF MOTOR-OPERATED VALVE FAILURES," OCTOBER, 1983 iS A COMPREHENSIVE REPORT OF MOTOR-OPERATED VALVE FAILURES SIGNIFICANT OPERATING EXPERIENCE REPORT (SOER) 83-9, OCTOBER 21, 1983 RECOMMENDS TESTING WITH DIFFERENTIAL PRESSURE.
APPROXIMATELY A 30% RESPOfiSE BY INDUSTRY TO SOER 83-9.
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Enclosure 3 to the Minutes of CRGR Meeting No. 80 U5I A-43 Contair. ment Emergency Sump Perfortnance Dr. T. Speis and A. Serkiz of NRR presented for CRGR review a proposed final resolution to USI A-43. The CRGR was requested to reconsnend several actions pursuant to resolving USI A-43:
- 1. Issue the staff's technical findings in NUREG-089/, Revision 1 for use as an information source by applicants, licensees, and the staff in addressing the design and operation of containment emergency sumps and BWR RHR suction intakes.
- 2. Issue Regulatory Guide 1.82, Revision 1, to include the technical findings reported in the new NUREG-0897 Revision 1. This would provide improved regulatory staff positions as guidance for assessment of sump perfonnance and BWR RhR suction intakes, including , debris blockage effects.
- 3. Issue NRC Standard Review Plan (SRP) Section 6.2.2, Revision 4, to incorporate the guidance provided by the revised Regulatory Guide 1.82 and the technical findings in NUREG-0897, Revision 1.
- 4. Issue a generic letter to all applicants and licensees outlining the potential for safety concerns related to post-LOCA sump blockage and the fact that the original Regulatory Guide 1.82 (Revision 0) is inadequate in light of the more current information resulting in Revision 1 to Regulatory Guide 1.82.
A copy of the viewgraphs used for the A-43 proposal is attached. The proposed A-43 resolution discussed was a revision to a previously presented proposal which was discussed at CRGR meeting nunter 66 on July 11, 1984. The new proposal was to take actions to assure that the technical findings and new guidance are available to the nuclear industry, to advise the industry of the inherent safety benefit to be gained by using the new guidelines, to state the t' ff's position that this new guidance will be used by the NRC only in new CP reviews and certain standardized design reviews, and to reconinend that the staff's technical findings on A-43 should be considered when insulation is replaced at operating plants.
Revisions in the prior regulatory analyses (discussed at meeting number 66) were discussed at this meeting in support of the proposed resolution. These are highlighted briefly:
- 1. Credit for operator action to recover ECCS flow that may have been lost is now given as a 50 percent likelihood that the operator will detect and
- 1 mitigate a loss of flow given a sump blockage event.
- 2. Plants of varying containment types and having different accident mitigating systems were evaluated to better define the risks inherent in each design type. Expected values of offsite consequences and
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l value/ impact ratios were calculated for all the plant types considered and l
I were generally such that much more than $1000/ person-rem would be required to effect safety-beneficial changes in the plants. In addition, the conservatism inherent in pipe break probabilities used in the regulatory analysis was recognized in the regulatory analysis and discussed in the CRGR meeting. Pipe break data used in the analysis has since been superseded by advanced fracture mechanics analysis and experiments. The more recent work shows that breaks in ductile pipes larger than eight inches in diameter, the size range necessary to provide a significant sump blockage probability, may occur at frequencies that are several orders of magnitude less than the frequencies used in the A-43 analyses.
The CRGR decided to reconnend approval of the proposed A-43 resolution presented, with several specific comments on changes that should be incorporated in the various documents:
- 1. The more recent work on fracture-mechanics resulting in lower estime.tes of pipe-break frequency should be explicitly recognized and referenced in the sunnary section of the regulatory analysis.
- 2. Implementation wording in the Regulatory Guide and SRP section should be modified to clearly show that the NRC staff use of the new review material will be forward-fit only.
- 3. The generic letter should clearly state that NRC application of the new guidance to an operating plant, particularly with respect to the NRC staff reviews of licensee 10 CFR 50.59 reviews, will be treated by the NRC staff as a plant-specific backfit action pursuant to 10 CFR 50.109.
- ? %q'o UNITED STATES g
! n NUCLEAR REGULATORY COMMISSION /<
g E WASW NOTON, O. C. 20$66 V f .-
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MEMORANDUM FOR: Victor.Stello, Jr.
Acting Executive Director for Operations FROM: James H. Sniezek, Chairman ,
Committee to Review Generic Requirements '
SUBJECT:
MINUTES OF CRGR MEETING NUMBER 85 l
The Comittee to Review Generic Requirements (CRGR) met on Wednesday, February 5,1986 from 1:00-5:00 p.m. A list of attendees for this meeting is enclosed (Enclosure 1). j
proposed Broad-Scope Rulemaking to Modify General Design Criterion 4 of 10 CFR Part 50. Enclosure 2 sunnarizes this matter (Category 2 item).
)
Enclosure 2 contains predecisional infonnation and therefore will not be released to the Public Document Room until the NRC has considered (in a public forum) or decided the matter addressed by the information. )
In accordance with the ED0's July 18, 1983 directive concerning "Feedback and l Closure on CRGR Reviews," the item above requires written response from the j cognizant office to report agreement or disagreement with CRGR recommendations ;
in these minutes. The response, which is required within 5 working days after receipt of these meeting minutes, is to be forwarded to the CRGR Chainnan and l if there is disagreement with the CRGR recommendations, to the EDO for decision- l making.
Questions concerning these meeting minutes should be referred to Walt Schwink (492-8639)
(WD ames H. Sniezek, Chairman omittee to Review Generic Requirements
Enclosures:
As stated cc: Comission (5)
SECY Office Directors l Regional Administrators ,
CRGR Members l G. Cunningham G. Arlotto J. Richardson
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, . e t 2 Enclosure 1 LIST OF ATTENDEES CRGR MEETING NO. 85 February 5,1986 CRGR MEMBERS J. H. Sniezek R. Bernero E. Jordan J. Scinto J. Heltemes R. Cunningham D. Ross OTHERS W. Schwink R. Hernan G. Arlotto J. A. O'Brien W. Shields K. Wichman R. J. Bosnak W. V. Johnston C. Y. Cheng J. H. Conran R. Vollmer R. B. Minogue Z. Shepard
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Enclosure 2 to the Minutes of CRGR Meeting No. 85 Revision to General Design Criterion (GDC) 4 Lea k-Before-Brea k )
At Meeting No. 85, the Comittee continued its review (began at Meeting No. 84) of a RES-sponsored proposal to modify GDC-4 to pennit broad-scope application of the leak-before-break concept and technology, in lieu of postulated high-energy pipe ruptures in certain licensing safety analyses.
Copies of briefing slides used by G. Arlotto and J. P.ichardson, RES, to guide the presentations at this meeting, and to respond to specific questions or cocumnts raised by CRGR members at Meeting No. 84 (or provided by individual CRGR members subsequent to Meeting No. 841 are attached. (See Attachments 1&2 to this Enclosure.) Copies o'T the drafe Comission Paper and Federal Register Notice (FRN), revised to reflect the RES responses provided in Attachmelits 1&2, are also attached. (Sce Attachment 3 to this Enclosure.)
Major points of discussion at this meeting regarding the proposels put forward by RES for revision of GDC-4 are sumari ed in the following:
- 1. The Comittee did not feel that the concerns expressed at Meeting No. 84 regarding the acceptability of the regulatory analysis provided in support of this proposed action had been fully satisfied, despite changes made by RES to the proposed Comission Paper and the draf t Federal Register Notice package in the interim. The Comittee's concern in this area arises from the fact that the basic regulatory analysis cited in support of the broad-scope revision of GDC-4 is the one done (by an NRC contractor) for the limited-scope revision of that rule (now pending final action by the Commission); and that analysis comes across as negative regarding the broad-scope applications of leak-before-break now proposed by the staff.
An important transition has occurred in the staff's posture from initiation of the limited-scope rule to this broad-scope revision proposal. At the limited-scope rule stage, the proposed revision brought forward by the staff was strongly and broadly supported by technical analyses and experimental work already completed, and by a "stand-alone" regulatory analysis that reflected that status. That is simply not the case with the current broad-scope proposal. Necessarily, then, the staff's posture is a more permissive one at this stage. The broad-scope proposal put forward now by the staff would permit licensees to apply leak-before-break technology more broadly than is allowed under the limited-scope rule, but only if they are willing to provide the analyses necessary to convince the staff that this would assure a level of safety equivalent to that provided by the postulated pipe rupture analyses done under existing requirements. The Comittee does not consider such posture inappropriate, given the circumstances; but the transition that has oc-curred in the staff's posture from the limited-scope stage to the current broad-scope stage has not been made clear enough in the proposed package.
Instead, the staff appears to be favoring or promoting a rule change that
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goes well beyond the limited-scope rule on a basis that is clearly not as we'l-developed as that provided for the earlier measure. The Comittee believes that it is important that further work be done by RES to clarify this aspect of the proposed broad-scope package before it is issued for CouTnent.
- 2. There was considerable discussion regarding the content of the last paragraph on page 5 of the revised draf t F_RN (Attachment 3). It was !
variously characterized in the Comittee's coments as weak, confusirg, l perhaps even erroneous in some of its dspects, and in any case unnecessary ;
as supportive argument for the proposed action. Specifically, the l reference to "...i.0CAs other than pipe rupture that place requirements on safety given i.e.,(systems andtostructures..."
a reason was considered treat only dynamic confusing effects in this in the context rulemaking);
the observation was made in this same context that 10 CFR 50.46 refers only to pipe rupture. It was also noted that the argument tnat the j improper installation of pipe restraints could cause a safety problem could as easily be made for other safety equipment as well, and so should not be cited uniquely in this case as a basis for rule change. With regard to this latter comment, the staff responded that an important issue 1 in this particular case was the proneness to install pipe restraints improperly, i.e., so that thermal expansion caused interferences and re-sulted in unintended stresses, (as was evident from numerous observations in the operating environment); the staff felt that it is, therefore, entirely appropriate to state this fact as a legitimate cause for concern and basis for staff action in this instance. )
l No agreement was reached on these points at this meeting; but the !
Comittee continued to recomend that this paragraph be revised and/or !
supplemented to accommodate the concerns expressed, or that it be removed ,
altogether, before the proposed package is issued for comment. In the '
Comittee's view, as it currently stands, the wording contributes to confusion on the issue and detracts from the proposal.
- 3. The changes made by RES to the wording of the second full paragraph of page 6 of the draf t FRN following Meeting No. 84 (e.g., removal of the word "additional)" were still not felt to have adequately addressed the Comittee's coments regarding " ... required investigations of potential indirect failure mechanisms that could lead to pipe rupture." No mention was made of the potential backfit considerations involved, or how that issue would be treated by the staff, in the event the need for such investigations arose but the requirement for such analysis was not already identified within the existing design basis of a plant that wished to apply leak-before-break technology.
The Comittee recomended that the staff clarify their intentions in this regard explicitly in this paragraph of the draf t LRN before it is issued for comnent.
- 4. The Comittee noted that the wording of the first full paragraph on page 7 of the draft LRN was still in need of further clarification (i.e.,
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beyond the changes made by RES subsequent to Meeting No. 84), with regard to the intended meaning of the phrase "... conditions consistent with the design basis for the piping." In discussing this coment, the staff made clear that what was referred to was the design basis approved in the FSAR ,
(as amended, of course, by any subsequent approved rule or Comission !
Order) . The Comittee recommended that appropriate changes more clearly reflecting that specific intent be incorporated into the draft FRN before it is issued for coment. (Note that the same wording appears in the text ,
of the proposed language of the revised GDC itself; so it is crucial that !
the intent of this wording be made clear.)
- 5. The Comittee noted that, in the last paragraph on page,f"of the revised l FRN, there is still ambiguity regarding whether the "10 value is 1 Tntended to apply only to the main coolant loop piping, or whether "...all l rupture locations in the fluid system piping" refers to smaller RCP piping sizes as well. Also, the Committee felt tha the tone of the staff's .
characterization in this paragraph of a "10 g" probabilistic pipe break value as equivalent to the approved design basis of correctly engineered components and structures under existing deteministic requirements, implies strongly (but incorrectly) that equivalence has already been established femally by the Comission.
The Comittee recomended that, before the package is issued for coment, alternative wording be developed for this paragraph along the lines of the I following:
- a. Indicate explicitly that the "10-6" pipe break value applies to large main coolant piping only; and
- b. State simply that either a correctly engineered piping system design which complies fully with existing deterministic requirements (including analyses of pg"stulated pipe breaks), or a probabilistic pipe break value of "10 (adequately demonstrated by suitable i analyses to the satisfaction of the staff), would be an acceptable 1 method of complying with the new broad-scope rule. Explicit conclusions should not be drawn regarding "equivalence" where two I methods of compliance are each technically acceptable in themselves, but may be sufficiently different (as in this case) that exact equivalence would be difficult to establish.
- 6. The Comittee comented that the wording of the revised draft FRN at the top of page 8 also seemed poorly chosen as an accurate description of the deteministic basis for licensing of nuclear designs. The Comittee recomended that the word "presumes" be struck from the first line on that page, and that the sutence be revised to the effect that " ..the licensing of plants on a deteministic basis relies on a safety review process that assures reasonably that components and structures are engineered to meet applicable requirements and codes."
- 7. The Comittee found the wording of the penultimate paragraph on page 11 of the draft FRN still confusing, even after the revisions made by RES
, j I J subsequent to Peeting No. 84 Even as revised,the wording of that para-graph seemed to imply strongly that the broad-scope rule being proposed .
was only meant to apply to already constructed (i.e., "as-built)" plants.
The regulatory analysis, on the other hand refers to savings to be j realized in future (i.e., yet to be built) plants. The staff explained i that what is intended is whether under construction or already in l operation, that theaspiping the piping system systems initially thatorare conceived actually) designed installed must (not just be properly !
analyzed.
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The Comittee recomended that this important, but potentially confusing, !
point be further clarified by revision to the proposed package before it 1 is issued for comment.
- 8. As a means of addressing generally specific concerns and questions raised l by the Comittee at Meeting No. 84, regarding how the staff intended to actually implement the acceptance criteria set forth in the proposed broad-scope rule (questions / concerns that arose naturally due to the absence of applicable proposed Reg. Guides, revised SRP sections, or any other fonnal staff guidance at this stage on how to resiew applications I seeking to take advantage of leak-before-break), the staff noted changes incorporated in the draft Comission Paper and draft FRN subsequent to Meeting No. 84, including additions to the language oTthe GDC itself. <
(See last page of Attachment 1 to this Enclosure.) Specifically, the staff I is now requiring explicitly in the body of GDC-4 itself ".. evaluation of other concerns such as corrosion, water hamer, and leak detection..."
which were principal among the CRGR concerns raised earlier. After thorough discussion of these topics at this meeting, it was further agreed to change the words "such as" to "including" in the proposed additions to the wording of GDC-4, and to include "fatigue" as another concern to be evaluated. In this same context, it was also agreed to delete the word "thennal" from in front of "aging" in the penultimate paragraph on page 12 ,
of the revised draft EN, to address the problem of aging more generally j in this new rule.
In conclusion, on the basis of the discussions and considerations reflected in .
the preceding and the Minutes of Meeting No. 84, the Comittee recommended I that proposed broad-scope rule package be sent forward for consideration by the Comission, subject to the changes recomended in the preceding. (Changes to the package should be coordinated with the ROGR Staff). The Chaiman also i directed that it be recorded that the sentiment was expressed within the j Comittee (but was not supported by the full Comittee), that the scope of )
this revision should be extended beyond just dynamic effects. i
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(CP = COMMISSION PAPERS FRN = FEDERAL REGISTER NOTICE)
- 1. CLEAR UP APPLICATION TO PIPING IN NON-SEISMIC CATEGORY I STRUCTURES .
SEE FRN, PAGE 11, SECOND BAR DOWN
- 2. CLEAR UP MARGINS REQUIRED FOR COMPONENT SUPPORT REDESIGN SEE FRN, PAGE 6, FIRST BAR AND PAGE 16, LOWER PART OF FIRST BAR
- 3. CLEAR UP REFERENCE TO IEB 79-14 ,
- 4. NO ACTION REQUIRED
- 5. DEFINE "DESIGN BASIS" BETTER
,,, $ SEE FRN, PAGE 7, FIRST BAR
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SUMMARY
OF ACTIONS ON BROAD SCOPE GDC-4 3 I
- 6. NOACTIONREdVIRED j i
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- 9. DISCUSS ASSOCIATED RG AND SRF SCHEDULE .
SEE CP, PAGE 4 AND FRN, PAGE 10 SECOND BAR .
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(CP COMMISSION PAPER; FRN = FEDERAL REGISTER NOTICE)
- 1. N0HAVE INCIDENT NOT DIRECTLY RELEVANT
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- 2. REVIEW DBA EFFECTS AS A FUNCTION OF BREAK SIZE PART OF LONG TERM EVALUATION PROMISED IN CP, PAGE 4 AND FRN, PAGE 9
- 3. LOCA FROM OTHER SOURCES ??
SG MANHOLE COVERS, VALVE BONNETS AND RUPTURE DISKS CI'TED
- 4. IMPROPER INSTALLATION OF PIPE WHIP RESTRAINTS SHOULD BE CONTROLLED BY DA PRONENESS TO MALFUNCTION DISCUSSED l
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ROSS LIST OF CONCERNS
- 5. AGING ??
COVERED EXPLICITLY
- 6. IS PIPE RUPTURE WITHOUT PIPE WHIP RESTRAINTS SERIOUS; TO WHAT DOES 10-6 REFER IN MOST CASES AN ISOLATED RUPTURED PIPE IS NOT A SERIOUS THREAT TO PUBLIC HEALTH AND SAFETY; 10-6 IS THE ANNUAL PROBABILITY OF PIPE RUPTURES CORE MELT PROBABILITY IS LOWER
- 7. LEGAL VIEWS ON AMENDMENT TO CONSTRUCTION PERMIT THIS SECTION WAS WRITTEN BY OELD
- 8. EFFECT OF RULE ON CORE MELT PROBABILITY PESSIMISTIC ESTIMATES SHOW SMALL INCREASES IN PUBLIC RISKS. REALIST!C ESTIMATES POINT TOWARDS DECREASES IN PUBLIC RISKS
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< 9. PIPING IN NON-SEISMIC CATEGORY I STRUCTURES SEE FRN, PAGE 11, SECOND BAR
- 10. HOW ARE NORMAL PLUS SSE LOADS COMBINED?
SEE SRP 3.9.3
- 11. WILL OUTAGE TIMES FOR LEAKAGE DETECTION BE CHANGED?
NOT EXPECTED. LEAK DETECTION OUTSIDE CONTAINMENT SAME AS INSIDE CONTAINMENT 4
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- ARE FREE OF THIS REQUIREMENT COMMENT ACCEPTED
- 2. WHAT ELSE BESIDES PIPING GIVES LOCA?
SEE SIMILAR COMMENT FROM ROSS
- 3. WHAT DOES HIGH CONFIDENCE IN SUPPORT RELIABILITY MEAN?
THE STATEMENT IS DELETEDs IT DEALT WITH REPLACING SNUBBERS ON COMPONENTS
. 4. CAN THE RULE REQUIRE ADDITIONAL INVESTIGATIONS OF INDIRECTLY INDUCED LOCA?
THE OFFENDING ADJECTIVE "ADDITIONAL" IS DELETED; SEE FRN, PAGE 6, SECOND BAR e
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- 5. DEFINE "DESIGN BASIS" WITH RESPECT TO FSAR DONE, SEE ARLOTTO
SUMMARY
- 6. GIVE A CLEAR DEFINIT 10_N OF "PROBABILITY OF FLUID SYSTEM PIPING RUPTURE" - -.
THE SUM 0F THE PROBABILITY OF ALL RUPTURES AT EACH LOCATION ON THE FLUID SYSTEM IS GIVEN IN THE FRN, PAGE 7. THIS DEFINITION HAS BEEN USED FOR SEVERAL YEARS.
- 7. IS THE COMMISSION STATING THAT Tile IMPLICIT DESIGN G0AL OF THE DETERMINISTIC REVIEW IS 10-6 FAILURES (= PIPE RUPTURES) PER REACTOR YEAR?
YES, ON PAGE 7 0F THE FRN
- 8. NEED FOR DESIGN VERIFICATION AND FABRICATION VERIFICATION FRN REVISED TO ACCOMMODATE THIS COMMENTS SEE PAGE 7, SECOND BAR
___ _ _ _ _ _ _ - - - - ._m._-. __m .___________-_______.______-__m.mm.._-___-____ ___.___-__-._ __ m _ -__ .._ _
- 9. INDICATE ACCEPTANCE CRITERIA ARE "STAFF GUIDANCE" RATHER THAN COMMISSION STANDARDS DONE, SEE FRN PAGE 10, THIRD BAR
- 10. DELETE REFERENCE TO IEB 79-114 RE*/ISED TEXT APPEARS ON PAGE 11, TillRD BAR
- 11. JJ. NORMAL PLUS SSE LIMITING CONDITION ?
YES
- 12. WHAT DOES "FINAL CRACK SIZE IS LIMITED SUCH THAT A DOUBLE-ENDED PIPE BREAK WILL NOT OCCUR" MEAN?
STABLE CRACK GROWTH, A TERM JUST USED IN THE TEXTS SEE PEMULTINATE PARAGRAPH ON PAGE 13
- 13. IN REG ANALYSIS, CHANGF ELD TO 0 ELD DONE
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THESE ANALYSES MUST INCLUDE, AS A MINIMUM, A DETERMINISTIC :
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SOURCES OF PIPE MPTURE, .
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