ML20133H222
| ML20133H222 | |
| Person / Time | |
|---|---|
| Issue date: | 06/20/1985 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2317, NUDOCS 8508090244 | |
| Download: ML20133H222 (10) | |
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P& NKER f 1 3 CERTIFIED COPY i .,
'. ISSUED: June 20, 1985 b b L L v U. M b }/
MINUTES OF THE COMBINED MEETING OF THE ACRS SUBCOMMITTEES ON METAL CCMPONENTS AND SEISMIC DESIGN OF PIPING MAY 23-24, 1985 WASHINGTON, DC The combined ACRS Subcommittees on Metal Components and Seismic Design of Piping met in Washington, D.C. on May 23 and 24, 1985 to review the NRC Piping Review Committee's recommendations in the following areas:
(1) Stress-Corrosion Cracking in Piping of BWR, (2) Evaluation of Seismic Design, (3) Evaluation of the Potential for Pipe Breaks, and (4) Evaluation of Other Dynamic Loads and Load Combinations.
Notice of the meeting was published in the Federal Register on May 2, 1985 (Attachment A). The schedule of items covered in the meeting is in Attachment B. A list of handouts, kept with the office copy of the mirutes, is included in Attachment C. There were no written or oral statements received or presented from members of the public at the meeting. E. Igne was the cognizant ACRS staff member for the meeting. .
Principal Attendees ACRS P. Shewmon, Chairman, Metal Components C. Siess, Chairman, Seismic Design of Piping C. Michelson, Member R. Axtmann, Member H. Etherington, Member J. Ebersole, Member M. Bender, Consultant J. Hutchinson, Consultant E. Rodabaugh, Censultant S. Bush, Consultant 8508090244 850620 PDR ACRS gil A;D CRIGINAIs Cortified By 8A -
2 May 23-24, 1985 Meeting i
f METAL COMPONENTS / SEISMIC DESIGN OF PIPING th t i
NRC Others L. Shao W. Shack, ANL R. Vollmer E. Johnson, Westinghouse J. O'Brien H. Clar, Westinghouse R. Klecker J. Nestell, MPR S. Hou P. Docherty, Westinghouse R. Bosnak R. Borsum, B&W G. Arlotto F. Sondgeroth, NUS D. Guzy W. Neely, TVA A. Taboada R. Cunningham, Duquesne Light M. Vagins C. Schlaseman, MPR L. Gallagher P. Telthorst, IPC C. Serpan W. Lobo, Boston Ed The NRC Piping Review Committee (PRC) was formed in response to a request from the Executive Director for Operations of the NRC that a comprehensive review be made of NRC requirements in the area of nuclear power plant piping. The activities of the PRC were divided into four tasks handled by appropriate task groups, as follows:
Pipe Crack Seismic Design Pipe Break Other Dynamic Loads and Load Combination Each task group has prepared a report appropriate to its scope. In addition, the PRC has prepared a Summary document listing its conclusions and recommendations. The five volumes make up the " Report of the U.S. Nuclear Regulatory Commission Piping Review Committee,"
NUREG-1061. The subtitles of the five volumes are:
Volume 1: Investigation and Evaluation of Stress Corrosion Cracking of BWR Plants Volume 2: Evaluation of Seismic Designs - A Review of Seismic Design Requirements for Nuclear Power Plant Piping Volume 3: Evaluation of Potential Pipe Breaks Volume 4: Evaluation of Other Dynamic Loads and Load Combinations Volume 5: Summary - Piping Review Committee Conclusions and Recommenda-tions Presentations of highlights of the above reports were given by Task Group Chairmen S. Bush, S. Hou, R. Klecker, J. O'Brien and L. Shao, respectively.
METAL COMPONENTS / SEISMIC DESIGN OF PIPING 3 May 23-24, 1985 Meeting It was stated that the suggested changes are quite substantial. The collective judgment of the PRC is that the implementation of the changes will have positive effects on both the licensing process and the safety and reliability of nuclear reactor power plants. Essentially all the principal suggested changes would lead ultimately to a simplification of licensing and, if implemented, plant piping would be more accessible and inspectible, thereby reducing occupational radiation exposure, costs, and likelihood of undetected defects. The PRC recognizes that imple-mentation of the recommendations will require changes in regulations, regulatory guides, and standard review plans (SRPs), as well as changes in the ASME Code. [ NOTE: The ACRS currently does not review SRPs and ASMECodeonasystematicbasis.]
The PRC has completed its review of the four reports and has established three priority cKegories, A, B and C, as well as subcategories within each. There a'e greater differences between A and B than between A-1 and A-2; for e cample, the PRC feels that Category A items are highly significant in the context of both regulatory requirements and research needs. Only Cetegory A items, listed in order of priority, are covered in this summary.
A-1: This item wo W reiax the loss-of-coolant accident (LOCA) criteria and apply leak-before-break (LBB) criteria instead. The implementation of such an action would permit removal of pipe restraints and jet impingement barriers, thereby enhancing the accessibility and inspectibility of piping.
A-2: Changes (increase) in seismic damping values have been accepted by the NRC Staff on a case-by-case basis. Broader implementation of these changes could substantially reduce the excessive number of piping supports, particularly snubbers. These changes in damping values have been incorporated into ASME-III.
A-3: Achangeinoperatingbasisearthquake(OBE)accelerationswould have a major impact on the design of new plants and extend well beyond piping considerations. In this instance, a decision is necessary concerning what is an appropriate ratio of OBE to SSE (safe sht. en=:cthgake). The ultimate aim is that the OBE not
METAL COMPONENTS / SEISMIC DESIGN OF PIPING 4 May 23-24, 1985 Mesting control plant design, which can be achieved by decoupling the OBE from SSE.
A-4: In the case of BWR intergranular stress corrosion cracking (IGSCC),
the PRC recommends the further implementation of ongoing practices to replace existing recirculation piping with materials known to be more resistant to IGSCC, such as 316 NG, 304 NG and 347 NG. The procedures currently exist and have been used to implement such actions.
A-5: This item represents an interface between the first three items, particularly A-1. PRC believes it is appropriate to decouple the LOCA from seismic events in systems where LBB is applicable.
A-6: This item relates to improvement and modification of leak detection systems. This issue impacts BWR-IGSCC as well as recommendation A-1.
Along with the above recommendations, the PRC has also prepared the following list of Category A items for research in order of priority.
A-1: The full-scale pipe fracture experiments of the NRC Degraded Piping Program should be completed. Of primary interest is the development and/or validation of fracture mechanics analysis techniques for ductile piping. Experimental variables should include flaw geometries, material toughness, axial-to-bending load ratios and static / dynamic loads.
A-2: Advanced techniques and procedures for crack detection and depth sizing should continue to be developed and incorporated in Code requirements. Included should be analysis of the human factor, equipment qualification and certification, and inspection techniques for detection and dimensioning of flaws in pipes repaired by the weld overlay process.
I
METAL COMPONENTS / SEISMIC DESIGN OF PIPING 5 May 23-24, 1985 Meeting o
A-3: Test programs (e.g., EPRI's piping capacity tests) for verifying seismic design margins and identifying failure modes for typical piping systems should be supported. Test results should be evalu-ated and recommendations provided for criteria changes (e.g., re-classification of seismic inertial stresses as " secondary"), as appropriate. Both cracked and uncracked piping systems should be tested.
A-4: Work under way at Lawrence Livermore National Laboratory on Babcock and Wilcox and General Electric reactor coolant loop piping designs should be completed to learn whether earthquake in combination with reactor coclant loop double-ended guillotine break may be excluded for these designs.
A-5: Work should be performed to determine the reliability of methods to predict leak rate and validate the reliability of leak-detection systems.
B. D. Liaw, NRR, discussed Professor Paris' concerns. Prof. Paris has stated that the original ASME Section XI IWB-3640 is " dangerous" because it did not account for low toughness welds that could lead to pipe failures below the limit loads. In addition, Prof. Paris has stated that the thermal stresses should be included in establishing the acceptance criteria. B. D. Liaw agrees with Prof. Paris' concerns and stated that the new proposed IWB-3640 will address these matters. Prof.
Paris also stated that the NRC Staff should require the utilities to postulate support failures or other physical limits. B. D. Liaw stated that the Staff did not agree because the supports margins of safety have not been changed.
J. O'Brien, RES, discussed the proposed modifications to GDC-4. There are two versions of the proposed modification: a limited or interim scope rule and a broad-scope rule to modify GDC-4 of 10 CFR Part 50.
The limited rule allowed use of " leak-before-break" technology only in ,
the primary main loop piping of PWRs. Dynamic effects are excluded, while the equivalent area of a double-ended pipe rupture is still
METAL COMPONENTS / SEISMIC DESIGN OF PIPING 6 May 23-24, 1985 Meeting ,
postulated as the design basis for emergency core cooling systems and containments. The broad-scope rule extends the limited-scope rule to the " leak-before-break" concept to all high energy piping systems in all light water reactors (LWRs) when certain acceptance criteria are met.
The two-step approach to rulemaking was adopted because safety and economic benefits could immediately be obtained by an amendment limited to the primary loops of PWRs because sufficient technical evidence had already been developed, reviewed by the NRC Staff, the CRGR and the ACRS. The acceptance criteria of the broad-scope rule have not yet been accepted by the CRGR and the ACRS. R. Bosnak, NRR, stated that changes to GDC-4 did not change the requirements of equipment qualification criteria. The margins for heavy component support integrity and structural design have not been changed.
Arbitrary intermediate breaks will be eliminated in branch pipes or runs if the stress and fatigue criteria are met. Changes reflecting this new criteria will be made tc the Standard Review Plan.
W. Johnston, NRR, discussed the matter of material properties degradation of aged cast stainless steel. He stated that information obtained from an NSSS vendor indicates that-models exist for predicting Charpy impact values for cast stainless steel piping material at the plant end-of-life. Criteria also exist for determining whether reference material properties are representative of aged end-of-life properties. Evaluation of crack stability and leak rate for through-wall flaws indicates that margins in the aged cast stainless steel material exists at its end-of-life. He further stated that a research program on cast stainless steel pipe is ongoing and further answers on this matter are expected.
Future Activities The joint subcommittee recommended that the full ACRS hear this matter at the August 1985 meeting.
NOTE: A complete transcript of the meeting is on file at the NRC Public Document Room at 1717 H St., N.W., Washington, D.C. or can be obtained at cost from Ann Riley & Associates, 1625 I St., N.W., .
Suite 921, Washington, DC 20006, telephone (202) 293-3950. l
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- Federzl Registtr / Vol. 50. No. 85 / Thursdzy. Msy 2.1985 / Notices 18755 h
e The a enda for sub%ct meeting shail olca 13 unwarranted invasion af electrical power, and a refueling cavity '
personal pris acy; and (3) inforrna tion water seal failure, respectively.%ere be as fo laws: - ,
the disclosure of which would was one abnormal occurrence at a fuel Thursday. Moy 22.1985430 s m. ont:7 ,
significantly frustrate implementation of cycle facility: the event involved the conclus/oo ofbusiness ,_. ;
8 proposed agency action: pursuant to degraded material access area barriers. Friday May M.1985-430a.m. amtilthe authority granted me by the Chairman's There were four abnormal occurrences' conclusionofbusiness . ti c.
~ -
Delegation of Authority to Close , at the other NRClicensees.One %e Sub u" i b.
Advisory Committee Meetings, dated
,anuary 15.1978. I have determined that invohed contaminated
- radiopharmaceuticals used in several m dificat.cowattee'windiscous ions to GeneralDesigut"'-~e- @.
Criterion.4 that will account far the ama;.7 these meetings will be closed to the diagnostic a. .dministrations. Two .
1, g
public pursuant to subsections (c) (4). (6) invohed therapeutic medical of theleak befom-bmak concep& 4, end (9)(B) of section 522b of Title 45.* misadministrations.ne other involved Pipmg systemin operating plants and p p
United States Code. ~.. -
significant internal exposure to iodine. plants under construc5on. Status of te . g NRC Piping Review r 'nmmittee reportsN , .: I
^
Further information about these - 125 to a hospital employee.%ere was meetings can be obtained from Mr. one a' bnormal occurrence reported by an 2 wiH also be - - q ,
Stephen].McClearly. Advisory ~ Agreement State: the event involved (NUREG-1061.
discussed at fhis meetigg.-;s Volumes,-3)M,m. *> i Committee Management Officer.
' ' contaminated radiopharmaceuticals .
,(* used in several diagnostic ~.. .'~
Oral stat'ements 'may be pre,sented by./
membais of t!;epablic with ocecurrename . -[
, J Natiunal Endowment for the . . ' ,l'~. ' ' .
of the S6mmittee Chairman;writtena .
Humanities. Wa shington, D.C. 20506, or call (202) 786-0322.
administrations. M > ~" C '
The report also contabis information " statements will be acx:epted and made U. I{
h Strphen J. McCleary. updating some previously repos tad .,,_. available to the Committee. Recordings > -
, Adsisory Committee. Mcnogement Officar.
willbe permitted only duringthose W % _=
' [m Doc. BM0060 Tiled 5-1-85: a.45 ern) abnormal occurrences...
Interested persons may revsew. t if he - portionsof themeetings.whenh:Gd-
. report at the NRC's Public Documenk -a p
aI
,,w, o coca im eim transcript is being kept, and questions e~;.
Room.1717 H Street. NW., Washington. . may be asked only by members of the A ".
DC or at any of the nuclearpower. plant - Subcommittee,its consnitents, and Stafi.'"
b cal blic Document Rooms '
[9 "
HUCLEAR REGULATORY g P d% WM MT" ' y COMMISSION statements should notify the ACES staff .
- Copies mi fic of NUREG-0090 .-' 'l Vol 7 No.3 (or any of the previous -
Abnormal Occurrence Report; Section repN b this series) may be purchased) canbe made.Q ' ~.74members as f
?
208 Repott Submitted to the Congress by callin6 (202) 275-2000 or (202) 275 3 arrangements , m 2171, or by writing to the Superinterident During thein1!1alportion of Ibe C . ' g Notice i4 bereby given that pursuant ,' of Documents. U.S. Government Printing meeting, the %bmmmittee, ,,.- along j with,,y to the requirements of section 208 of the
- e. Post e Box 37082. ' , any ofits consultants w .
f_
4 5- ) ' anay.jbe =\
Energy Rebrganization Act of 1974, as . Washington. D.C. 20013-7982. A yet r's : present, may exchange reh minaryp.ho y ,f -
amended, the Nuc! car regulato . ~
Commission (NRC)haspublish d and subscription to the NUREG-0000 senes views regarding matters to be +.Q. 'ge publication, which consists of four '
issued the periodic report to Congress issus.ls also available.Docum-nts may. ,considered .
'^'
during . . it the bala
' in abnormal occurrences (NUREG-W30, be purchased by check, money order. .Ihe--Subco'mm!'ttee
' meeting. wiB thanhaar ' . ', '" -
Vol 7. No. 3). sayasterCard, or charged to a W I'.
Under the Encrgy Reorganization Act s presentations by and hold discussions ~.
of1974. which created the NRC. an Dep s3t Account.- with representatives of the NRCStaff.T h Cop e 3 '
ebnormal occurrence is defined as "an p, chjs e Q',I'Wical its consultants, and otherinterested . . ..
unscheduled incident or event which the Information Service. Department of .. Persons regarding this review. r-% . .
3 Commissmn (NRC) detennmes la Commerce 5285PortRoyalRoad,- . "- / Furth'er information reganhng topics '.s. f signif . .st from the standpomt of pubh.c Springfield VA 2218L P ' P ' W - tobe discuss'ed, whether the meetingu . - i
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Dated at Washingtoft.DC.this 260 dah of ' . has been cancelleclor rescheduled. the ,,
e rm nat n.$a d on na Chatnnan'sMng on gens b & ^
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published in the Federal Register (42 FR ~ April taas. Q 4.m u :. w u 4 apportunity to present oral statementa "} ,
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10950) on February 24.1977. that etents For the NucleaiRegulatory Coinmission. s John C. Hoyla. acd the time allotted therefor can be - . .
j involving an actualloss or significant . [.' ., , . .
obtained by d prepaid telephone call to ,. ,t reduction in the degree of protection Ass' fant Secretory offbe Comm1sslon' .
the cognizant ACRS staHnsen2ber.* ;
against radioactive properties of source. [ . ac. 85-1009o Fded 5-1-85. 8.45 am)- Elpidio.Igne (telephone 202/634-1414) -e special nuclear, and byproduct materials si s coot ne&ei-as '. - - between 8:15 a.m. and 520 p.m. EDT.7-are abnormal occurrences. .
This report to Congress is for the th- Persons planning to attend this meeting . .
' calendar quarter of 1984.The report are urged to cantact the above named Advisory Committee on Reactor ' individual one or two days before the ' -
identifies the occurrences or events that safeguards; Subcommittee on Metal the Commission determined to be scheduled meeting to be advised of any Components and Structural significant and reportable; the remedial changes in schedule.etc.,which may Er.gtneering; Meeting actions that were undertaken are also dncribed. Daring the report period. The ACRS Subcommittee on Metal . have '
occurred.
Dat,ed. April 29.' toss. .
there were four abnormal occurrences at Components and Structural Engineering ...- -
M.'"*" E.Libarkin. - .., .
the nuclear power plants licens-d to will hold a combined meeting on f.tay 23 opet ate.These insolved degraded and 24,1985. Room 1046.1717 H Street. . AssistantExecutiveDirectorforproject . ,
Rl'"-
isol. tion saltes in emergency core NW. Washington DC. -
coahng systems. degraded shutdown The entire meeting will be open to- Im Doc. 85-10693 Filed 5-1-85: 8.45 am] '
s)sicms, a luss of offsite and onsite AC public attendance. -
, enseocooc m oeim . .
'ATTACHMEN'T A.~
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- fk4Ciei2, REVISED: Apr. 29, 1985 TENTATIVE SCHEDULE
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COMBINED MEETING OF ACRS SUBCOMMITTEES ON METAL COMPONENTS AND STRUCTURAL ENGINEERING MAY 23-24, 1985 WASHINGTON, D.C.
May 23, 1985 gM 9: 40
- .I Introductory Statements and Coments -0:30 - titf0 P. Shewmon and C. Siess; other members / consultants II. NRC Piping Review Committee Briefing VA. Introduction, Background and Schedule 04 45 9:00 9:30r
~
Shao/Vollmer -
io.2 o Mq.s - M440 v' B . 1. I, Pipe Crack, Bush
. Status cf implementation (NUREG-0313,Rev. 2) io.,g ine-o B. D. Liaw ' b "' N > C - #+40- tet44 N*** BREAK *** 1N-it..o C. Vol. II, Seismic Design of Piping Hou 11:00- M+ M w_
- 1. " Stiff" vs. " Flexible" piping system designs and comparison with designs of other countries, e.g., Japan, FRG, etc.;
also discussion of the possible reasons for higher reliability of snubbers in IDO - D3 L nuc plants in Japan ichudsen/ Bush itT00 - 12:30 (Bosna. t.; L PAQ4 12 .1, 4,,
M+39 - 4+-3p
- LUNCH *** n4 a:W D. Vol. III, Pipe Break, Klecker 1+39-4+40
- 1. Research programs on cast stainless tTo-130 steel degradation C. Serpan e 3:30 Implementation of Pipe Break Concept -
ts 4ab '
GDC-4 modifications, O'Brien (RES), 3ea8 - 4,00-I Wichman (NRR), Shields (OELD) su W.Sg
- 8REAK *** 4:00 - 4:15
- b. NRR discussions on leak-before-break concept including, but not limited to:
- cast stainless steel toughness degrada-tion (aging)
- review of degraded cast stainless steel data for W. B&W, CE and GE plants, b MN' *I
- app y 4:15 - 9300 W. Johnston s 9 '.L 44{ - Pr *
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- 3. Status of P. Paris' concerns, B. D. Liaw 5:00 - 5:15 /
- RECESS * *
- 5:15 May 24, 1985 (Reconvene at'8:30 a.m.)
II.D.4. Status of other technical changes to piping designs, e.g., component supports criteria
["... rigorous reexamination of the integrity of heavy component supports under all desicn conditions" (ACRS letter of June 14,1983).!;
elimination of arbitrary intermediate pipe breaks, etc. to'tC R. Bosnak 8:30 - N
-c -
II. E. Vol. IV, Combination of Dynamic and to:30 - ii' if Other Loads, J. O'Brien -9 4 0 -10:00 F. Vol. V, Executive Sumary n:ss t\'80 40.00-11.00 Shao/Vollmer s e '. tr - t o '.% 0 g *** + h00-11:15
- BREAK III. Discussions on the licensing aspects of li 0 5 Regulatory Guides 1.46 and 1.48 L' 9 R. Bosnak/ Richardson H+H-12:00 IV. Subcommittee discussions, future activities, and 1r.0 5- 1:05 Adjournment N122
O ATTACHMENT C LIST OF HAND 0UTS COMBINED MEETING OF ACRS SUBCOMMITTEES ON METAL COMPONENTS AND SEISMIC. DESIGN OF PIPING MAY 23-24, 1985 WASHINGTON, DC Attendee Sign-In Sheets
- 1. Larry Shao, RES, Introduction and Background, NRC Piping Review Committee
- 2. Spencer Bush, " Summary of Inspection Findings on large Piping in All Operating BWR Inspected According to IEB 82-03 and 83-02"
- 3. B. D. Liaw, Prof. Paris' Concerns
- 4. Shou-Nien Hou, NRC PRC Task Group on Seismic Design
- 5. NONE
- 6. R. W. Klecker, NRC, PRC Presentation: Potential for Pipe Breaks, NUREG-1061, Vol. 3
- 7. C. Serpan, RES, Materials Engineering Branch, Div. of Engineering Technology, Research Programs on In-Service Degradation of Cast Stainless Steel
- 9. William V. Johnston, RES, Aged Cast Stainless Steel; 9.a. Non-Proprietary 9.b. Proprietary
- 10. R. Bosnak, NRR/DE, PRC Technical Recommendations Status in Licensing Reviews