ML20153B143
| ML20153B143 | |
| Person / Time | |
|---|---|
| Issue date: | 04/19/1988 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2567, NUDOCS 8807120721 | |
| Download: ML20153B143 (14) | |
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CERTIFIED COPY DATE ISSUED: April 19, 1988
SUMMARY
/ MINUTES OF THE ACRS SUBCOMMITTEE MEETING ON STRUCTURAL ENGINEERING MARCH 30, 1988 CULVER CITY, CALIFORNIA The ACRS Subconinittee on Structural Engineering met on March 30, 1988 at the Pacifica Hotel in Culver City, California to review the EPRI/NRC Piping and Fitting Dynamic Reliability Program (PFDRP).
Notice of the meeting was published in the Federal Register on March 14, 1988 (Attachment A). The schedule of items covered in the meeting is in Attachment B. A list of handouts kept witt the office copy of the minutes is included in Attachment C. There were no written ur oral statements received or presented from members of the public at the meeting. E. G. Igne was Cognizant ACRS Staff Member for the meeting.
Principal Attendees ACRS D . Siess, Chairman l
P. G. Shewmon, Member D. Ward, Member S. Bush, Censultant E. Rodabaugh, Consultant l
NRC E Guzy l Others S. Tagart, EPRI l Y. Tang, EPRI I W. English, GE l S. Ranganath, GE eso)120721 880419 K. Herz, ANCO PDP ACRS PDR V. DeVita, ETEC 2567 ,
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Minutes / Structural Engineering 2 March 30, 1988 Highlights
- 1. D. Guzy, RES, presented a brief outline of the Piping and Fitting Dynamic Reliability Program (PFDRP). The emphasis of this program is to determine a technical basis for the design of piping components subjected to dynamic inertial loads. The objectives of the program are
- 1) to identify dynamic failure mechanisms, 2) to provide high-level nonlinear response data and 3) to develop improved ASME code design rules. The EPRI/NRC cooperative program involve 1) General Electric, San Jose, 2) ANCO Engineers, 3) ETEC and 4) MCL (Material Characterization Lab.). Its consultants involve 1) E. Rodabaugh, 2) R.
Kennedy, 3) D. Senders ~, 4) R. Cloud, 5) D. Munsen, 6) S, Moore, 7) R.
Bosnak and 8) L. Severud. The program was initiated in the spring of 1985. All testing has been completed except for a retest of a systems test. The program will be completed in June 1988 with final reports shortly thereafter. This program maintained interaction with the ASME and the PVRC Standards groups. Preliminary results have been published l
in Technical Journals and by SMIRT. D. Guzy stated that the main thrust on the issues came from the NRC Piping Review Cornittee, which raised concerns about overconservatisms in inertial load design of piping
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In reply to a question, D. Guzy stated that cast piping components are not included in the matrix of test specimens.
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Minutes / Structural Engineering 3 March 30, 1988
- 2. S. Tagart Jr., EPRI, presented an introduction and overview of the PFDRP. Early pipe design criteria were based on semi-static fatigue In 1975, Japanese research showed tests and static failure criteria.
large dynamic margins and a fatigue ratchet failure mode for piping; no collapse failure was observed. Recently PVRC and the NRC Piping Review The Committee recommended a program to improve piping design criteria.
EPRI/NRC PFDRP was in response to the PVRC and NRC reconnendations.
Before this program was initiated the following was known, o Piping dynamic margin was large but uncertain, o Piping failure mode for reversed dynamic loading is ratcheting and fatigue and not static collapse, o Reduction of piping code margins required convincing experi-mental evidence plus engineering understanding, o Modern nuclear power plants had too many snubbers.
Based on the PFDRP, the following is now known about the behavior of piping systems under seismic loading conditions:
o Why static collapse does not generally occur.
o What types of dynamic loads can collapse piping, i.e., water hammer type loadings, o How to predict approximately component test results from fitst principles, o Limitations on linear dynamic analysis, o Clarified concepts of apparent damping, i
Minutes /Strectural Engineering 4 March 30, 1988 o Why sound piping systems are so fundamentally resistant to t seismic and other cyclic-type dynamic inputs i.e., true damping is very high at moderate dynamic ductility o How to understand ratcheting.
S. Tagart stated that, based on the preliminary results of the PFDRP, opportunities and challenges abound to optimize piping system design for safety ano cost. In addition, significant code margin reduction prcposals will be forthccming, in areas such as:
o Independent support motion (ISM) with SRSS, o Simplified static analysis, o Non-linear methods, o SAM modifications, and o Design by rules rather than by analysis.
- 3. W. English, GE, discussed the PFDRP program structure, objectives and test programs (system component, and specimen test). The major objective was to develop an improved, realistic and defensible set of piping design rules for inclusion in the ASME code. The other objec-tives are as follows:
o Determine actual failure mechanisms for piping systens and components, o Measura piping system damping for various strain levels over a range of frequencies.
Minutes / Structural Engineering 5 March 30, 1988 o Determine influence of support failure on piping system response, o Show effect of low frequency input to piping from buildings subjected to large amplitude earthquakes.
o Demonstrate that piping components and systems can tolerate earthquakes much larger than the SSE without pipe failure, o Develop laboratory procedures for quantitative evaluation of fatigue-ratcheting.
o Quantify economic benefits of new design rules to utilities by application to typical piping system.
o Simplify piping system dynamic analysis.
Components tested (6 inch diameter, schedule 10,40,80) were elbows, tees, reducers, nozzles and support connections fabricated of stainless and carbon steels. Plan for the component tests was for the input peak to be about 0.5 Hz below the component naturel frequency. Fatigue-ratchet cracking in 2-3 seismic inputs was the desired result. In most instances, the desired results were achieved with the schedule 10 and 40 components; schedule 80 components cracked in abnot 5-9 seismic inputs.
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00servations from the component tests are as follows:
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o Dynamic load reversals prevents collapse, l
o Seismic loads behave like secondary not primary stresses.
) o Ratchet failure loads are much greater than the SSE.
o Ratcheting does not impair functionality.
o Damping for large dynamic loads is greater than shown in l
r Minutes / Structural Engineering 6 March 30, 1988 Regulatory Guide 1.61.
o Amplified higher frequenc,y safety relief valve (SRV) load cause small response.
o Failures are characterized by fatigue and/or ratcheting, not static collapse.
Systems test were run with components similar to those tested in the component tests. PWR cooling water chemistry with an internal pressure of 1000 psi at room temperature was used in the systems test. Three hydraulic actuators simulating three support system dynamic inputs were employed in these tests. Observations from the system tests confirmed the observations from the con'ponent tests. It was extremely difficult to fail piping with simulated seisn.ic loads. With a smile, W. English, stated that the buildings will fail long before the piping wfil.
Water hamer tests were run with loops fabricated with 3-inch and 6-inch dian'eter, schedule 40, carbon steel pipe. Tests were run with and without pipe supports and with supports simulating pipe branches and pressure vessels.
i Loading conditions for the water hamer tests were as follows:
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o simulated steam haniner, o hard system acoustic, and l
o water plug.
Internal test pressures in the loop varied from 150 to 2000 psi.
Minutes / Structural Engineering 7 March 30, 1968 i
Preliminary observations from the water hamer tests are as follows:
o Water slug causes primary loading and can collapse the pipe o Steam hamer and hard tests behaved more like secondary loading and did not cause the pipe to collapse, o Piping support can tolerate loads about 10 times rated load without failure, o Pipe can tolerate transient pressures to about 2 times burst pressure without failure.
o As a basic rule; design piping systems to avoid water hammer.
Specimen tests were also run. The objectives of the specimen tests are listed below:
o Develop lab specimen to evaluate fatigue ratcheting with mean stress, o Correlate specimen behavior with compenent behavior.
1 o Investigate fatigue ratcheting effects at 550 F.
Results of the tests are as listed below:
l o 2-bar test conservatively estimates effects of ratcheting on cyclic life.
o Beam and pipe specimen confirmed 2-bar test results.
o With controls on cumulative ratchet strain, mean stress and j
temperature did not affect cyclic fatigue life.
o Cyclic creep observed in low frequency specimen testing may l
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Minutes / Structural Er.gineering 8 March 30, 1988 not be present in high frequency seismic loading.
- 4. S. Ranganath, GE, Discussed potential piping design rule changes as The following ratchet crtierion is based on a result of the PFORP.
results of component and system.
o Where good data are available, the measured strains can be used to determine the stress level below which there is not ratcheting. Fortypicalmeanstressvalues(0.5Sm) significant ratcheting was not observed for stress amplitudes below approximately 6 Sm for both carbon steel and stainless l This stress value may be used as steel at room temperature.
1 the stress level below which special fatigue or ratcheting is not necessary, S. Ranganath proposed the following new code limits for the short term:
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Level B 3.0 S or 2.0 Sy m
4.5 S or 3.6 Sy Level C m 6.0 S or 4.0 Sy Level D m 0 Fatigue analysis for Level B; no specific ratcheting controls need be considered.
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9 Minutes / Structural Engineering March 30, 1988 o
For the long term goals of code implementation, S. Ranganath stated that test data show that piping components can tolerate loads well beyond He feels that static analysis may in fact be current code limits.
acceptable in most cases resulting in significant simplification and that the long term design analysis goal should be to implement realistic stress limits with simpler analysis methods.
- 5. In closing, D. Guzy, RES, discussed other RES piping design The elements research programs as defined in NUREG-1222 (forthcoming).
of the program include 1) piping response methods, i.e., damping, ISM method, high frequency, closely spaced mode and nonlinear response, nozzle flexibility and design, 3) support design, 4) cumulative effect of piping criteria changes, 5) IPIRG (degraded pipe studies) and 6) piping reliability studies.
Subcommittee Action:
A subcommittee report to the ACRS will be presented.
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I;0TE: A transcript of the meeting is available at the NRC Public Document Room, 1717 H St. NW. Washington, D.C. or can be
! purchased from Heritage Reporting Corporation, 1220 1. Street,
( NW., Washington, D. C. 20005, Telephone (202) 628-4888.
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ATTACHMENT A 8290 F;deel RIgist:r / Vo!, 53, No. 49 / Monday, March 14, 1988 / Notices fa) Extending the K, Factor curve up to Alternotive to the ProposedAction Mond;y, March 18,1986-4.30 a.m. Until Since the Commission concladed that.
the Conclusion oOusbm ren 1
- there are no significant envira====aal The Subcommittee will be briefed ami (b) Clamping the Upscale Setpoints effects that would resnlt from the review:11) ne Human Factors Researdi for the Rod Block Monitor in TS Table proposed action, any attematives with 332 at h 1m recirnlath now Program plan,(2) the Fitness for Daly equal or grea:er environmental impseta Rule, and (3) Policy Statement on value. need not be evaluated. Training and Qualification (tentstire).
(c) Iru:reasing the Motor Generator Set The principal alternstrve would be to Oral state.sumts may be presented by mechamcal and electncal stops in TS deny the requested amendrnent.his mambers of the pubHc with the 4.4.1.1.3 to physically allow for would not reduce environmental concurrence of the Wremittee increased core flow. impacts of plant operation and would
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Chairman: written statemeWa wid be ~
The proposed action is in accordante result in reduced operational fwxibuity. accepted and made available to the with the licensee's application for Committee. Recordings will be permitted amendment dated December 14,1987. A/ternative Use ofResoames only during those portions of the The Needfor the Pmposed Action This action does not involve the use of rneeting when a transcript is being kept, any resources not previously considered and questions may be asked only by The proposed chaoge to the TS is in the Mnal Environmental Statement for members of the Subcommittee,its required in order to provide the license the Hope Creek Generating Station, consultants, and Staff. Persons desiring with appropriate safety limits for dated December,1984. to make oral statements should notify operation with the Cycle 2 reload core, the ACRS staff member named below aa greater operational flexibility during the Agencies and Ar.rsons Consuhed: far in advance as is practicable so that initial portions of the operating cycle. The NRC stafireviewed the licmsee's appropriate arrangements can be made.
improwd power ascensloo capab>hty to request and did not consult other During the initial portion of the full power and addJtional abibty to agencies or persons meeting. the Subcommittee, along with compensate for reactmty reductmo due any of its consultants who may be '
to fuel exposure dunng the operataag Finding of No Significant impact present, may exchange preliminary cycle. views regarding matters to be The Comtnission has determmed not ravironmento/ Impacts of the Pmposed to prepare an environmentalimpact considered during the balarrce of the Aerito staternent for the proposed hceos, meetmg.
a mendment. The Subcommittee will then hear The propoed revisians to the Based upon the foregmng presentations by and hold discussions Technical Specification limits environmental assessment, we conclude with representatives of the NRC Staff, adequately compensate for the propocad that the proposed action will not have its consultants and otherinterested chariges m the fuelload and for s gnibcant effect on the goality of the persons regarding this review, operation wah increased core Dow and human envirorunent. Further information regarding topics extended load line limits. The proposed to be discussed. whether the meeting changes do not increase the probabihty For further details with respect to this action. see the application for has been cancel led or rescheduled, the or consequences cf accidents, no Chairman's ruling on requests for the changes are being made in the types of amendment dated December 14.1987 which is available for public inspectice opp rtunity to present oral statements any effluents that ruey be released and the time 4Holted therefor can be offsite, and there is no significant at the Commission's Public Document j Room,1717 H Street. NW., Washington, obtained by a prepaid telephone call to increase in the allowable individual or the cognbant ACRS staff member, Mr.
and at the Pennsville Public Library,190 cumulative occupational radiation. . So th Broadway, Pennsville. New Jersey Herman Alderman (telephone 202/634-exposure. Acconfingly, the Commisstoa 3297) between 7:30 a.m. and 4.30 p.m.
080"O' concludes that this proposed action Persons planning to attend this meeting would result in no significant Dated a t Bethesda. biaryland. this 7th day are urged to contact the above named radiological environmen tal i mpa ct. of March 1988. Individual one or two days before the With regard e potential non. For the Nclea r Regula tory Cosnrnasaon. scheduled meeting to be advised of any radiological impacts. the proposed . Walter R. Butler, changes in schedule, etc., which rnay change to the TS invohes systems afector. Project areceomt, /4 omma o/ have occurred, lochLed with.in the testricted area aa Reactar Pro,ects Ull. Offar c/Nxlear Date3f arch 7,1988.
defined in 10 CFR Part 20. It does not ReacwAqwlobo* Morton W. ubarkin, affect non-tadiological plant effluccis [Ht Doc. 46-5479 Fded 3-11-84 en am) .4ssistant Executive afectorfor Project and has no other emironmentalimpad. suo coo ne -ew R, w,,v.
Therefore, the Coramission concludes that there are no sMant non- Advisory Comrnittee on Reactor p Doc. m FM 31W W W radiological environmental impacts safeguards Subcommittee on Human associated with the proposed Factors; Meeting y l amendment. Advisory Committee on Reactor ne Notice of Consideration of ne ACRS Subcommittee on Human Factors wTil hold a meeting on March 28' Safeguards Structural Engineering; Issuance of Arundment and Meeting 1988. Room 1048,1717 H Street NW, Opportanny for Prior Hearing in Connec4Jon with (Ws action was Wa shington, DC. The ACRS Subcommittee on pubhahed in the Federal Register ao The entire meeting will be open to Structural Engineering will hold a i janaary 14,1988 (53 F'R 972). No request public attendance. meeting on March 30.1968, at the !
for besi4sig or pethm for leare to The ageada for the sul4eci mac<ing Pacifica Hotel. 6161 Cerrt'm ets Avenue, intervene was f! led fuDueys this notice. shell be as follows: Culver City, CA. ;
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l Federal Register / Vol. 53 -No;-49 / MmdayTMarch % 1se8 / Nottasf .
Any person erho has Aled a petition for f considensg issuance of an ..nendment leave to interscoe or who has beer ,
The cntoe meeting mill be open to to Focity Operating Liccase No. NPF- admitted as a party may amend tse .l . f 21 issued to Washington PubDc Power petition without requestieg leave M the 0' pubhc attendance.The agenda for Supply the subjectSystemmeeting (the liwnsee) for Board up to fiNen 05] den pdu to the 05 chsll tw as follows- PCr first prehearms conference adveMed M ,
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Wednesday, March 30.1914-430 a m. E',a.aue lect 2 located inof Washington Benton Conly. Nuclear the proceeding.but such an ameMed
% shirtston The request for amendment petition must satisfy the specJlicity
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't Until the Conclusion of Business was submitted by letter dated January 5. regwements described above. ' M The Subcommittee williniew the 1N31 Reference GOLM&o02). Not later then fiNen (15) days prior to .!
The proposed amendment would the Grst prehearing conference Piping and Fitting Reliability ProgramOral allow the operation of statements WNP-2 with mayscheduled be presented b) a petlioner in the proceeding.
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, memt> cts of the pubhc with t!.e control of vahe RHR-We transferred shall fue to a supplement to the petttion to concurrence of the Subcomnutlee the Alternate Remote Shutdownintervene Panel wh:h rnast rechede a hst of Chairman: written statements w di dunns be norma operation. This action if the contentions which ate scopht to be accepted and made asailable to the approwd would result in resolution of litigated in the siatter. and the bases for Comm ttee. Record ngs wi!! be permitted concern over potential consequences of each contention set forth with tm!> during those portions of the reasonsbie specificity. Contentions sha!!
meeting when a transtnpt a being kept. a postulated control room fire. Prior to issuance of the proposed and questions ma> be asked only by be limited to mettets within the store of laense amendment. the Commission the amendment under consideration. A wdl has e made findings required by the petitioner who fails to fde such a mernhers of the Subcommittee. its Atomic Energ> Act of 1954 as amended consultan's and Staff Persons desiring supplement which satisfies these to make omi statements should notify (the Act) and the Commission's requirements with respect to at least one the ACRS staff member named below Dy as regulations ^
Ap*il13.19fA the beensee may ide contention will not be permitte far in adeance as a practicable so that panicipate as e party.
appropriate arrangernents can be mode a request for a hearing with resie cet t .I hose permitted tointervene become Durmg the initial pothon of the issuance of 'he amendment to g g meetirg the Subconmnttee along with subject facihty operatinglicense and gg . g any person whose interest may be gg any of its consultants who may be inte+vene, and have the CPPortmity to present. may exchange preliminary affected by this proceeding and wh P8"'.cmate fuuy in the condect of the view s rearding matters to be wishes to participate as a party in the heanns includmg the opportunity Ic considered dunng the balance of the proceeding must file a written petition present evidence and cross examine meeting for leat e to intenene. Requests for a witnesses.
Tbc Subcommit!ce will then hear hearing and petitions for leave to A rt gaest for a hearitt3 or a petition prescntations b) and hold daussions, intervene shall be filed in accordance for leas e to mtervene must be IUed wi with represenlaines of the NRC Staff, with the Commission's "Rules of the Secretary of the Commission. U.S Its consultuts, and other interested Practice for Domestic Licensing Proceedmgs" in 10 CFE Part 2. If a Nuclear Regulatory Coinmissina.
Washingen. DC 20555, Attention:
persons regard ng this reuew.Further request for information a t cering or regarding petition for topich Docketmg and Sm Emit w may tobe discussed whether the meeting leave to inten ene is fded by the above has been cancelled or rescheduled, the date, the Commission of an Atomic be dela cred to the Comrnission : Pubh Chairman's ruling on requests for the Safety and Licensing Bontd. designated Document Rooci.1717 II Street. NW..
% ashington. DC. by the above date.
opportunity to present oral statements by the Commission or an Atomic Safety and Licens'ng Board Panet wd! rule on u hue pet 2tions are ided during the L4t d it is and the finie allotted therefor can be the request and/or petition, and the ten (10) days of the not obtained by a prepaid telephone call to eequested that oner theorpetih(ce peno .
the cognizant ACRS staff member. Mr. Seuetery or the designated Atomic representative for the petitioner Elpidio Igne (telephone 202/634-1414) Safety and Licensing Board wdlissue a promptly so inform the Comminion by a between 7.30 a m. and 4:15 p m. Persons notice ot hcaring or an appropnale toll. free telephone call to % estern planning to attend this meeting are order.
urged to contact the above named As required by 10 CFR 2.714. a Union at (800) 325-6000 (in Missouri indisidual one or two days before the petition forleave tointervene must set(800) 342-6?o01. The M esteen Ur.ico operator should be gn en Datagram scheduled meetmg to be advised of anyforth with partculanty the interest of changes in schedule. etc., which may the petitioner in the proceeding. and Identific.ation Number 3 37 and the how that intccest inay be affected by the following messette addressed to George I
results of Ihe proceeding.The petition W. Knighton: Petitimer's name and have occurred' ,1968 telephone number, date ptMition was Dated March 9 shodd specafitaUy explain the resaons Morton W. Markin, why intervention sbould be perrnittedmaued; plant name; and peblication date end page number of this Federal Assistant Executive Directorfor Pmfectwith particular reference to the Register notice. A copy of the petition Retie w. following factors:(1) The nafure of the lFR Doc. B&-5Mt Filed 3-11-e& 8 45 amj suo coot two-os-a petitioner's right under theshodd Act aise General be cent to the Office of the toCounsel-Rockville.
bemade a party U.S. to the
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nature and extent of the petitioner's Nuclear Regulatory Commission.
property, financial or other interest inWa % w.DC N eM M W.
[ Docket No. 50-397) & procneng: and O) ee ponMe Nicholas S. Reynolds. Esq.. Bishop.
Washington Public Power Supply effect f ariy order wluch may be Cd. W and Reps, m 8d"#^
System; Consideration of issuanc'e petitioner,so, the pumding on de Seventeenth Street NW Washington.
interest.The petitaon DC 20030 and Mr. G.E. Doupe. Esq.,
should Amendment to Factttty Operating alsoldentify the specific aspectts) of the Washington Public Power Supply ucense and Opportunity foe Hearing System. P.O. Box 968. 3000 George seWecA matter of the proceeding as to The U.S. Nuclear Regulatory which petitioner wishes to intervene.
Commission (the Commission)is
- - ATTACHMENT B 4
REVISION 1 March 9, 1988 TENTATIVE SCHEDULE ACRS SUBCOMMITTEE ON STRUCTURAL ENGINEERING VISIT AND MEETING LOS ANGELES, CALIFORNIA, MARCH 29-30, 1988 Visit, March 29, 1988 B:00 a.m. 1. Leave from Pacifica Hotel & Conference Center 9:15 a.M. 2. Arrive ETEC 9:15 - 12:00 Noen 3. Visit ETEC 12:00 - 1:00 p.m. LUNCH 1:00 - 2:00 p.m. 4 Travel to ANCO 2:00 - 5:30 p.m. 5. Visit ANCO 5:30 - 6:30 p.m. 6. Return to Pacifica Hotel Meetino, March 30, 1988 8:30#- 8:45 a.m. I. Opening Stater.ents/ Introduction - C. Siess II. Introductory Statements & Overview 8:45 - 9:M a.m. D. Guzy, RES 9:J5 - 9;4 a.m. S. Tagart, EPRI i0 S3
- 9) 10 *****
9,A$ - 10:06a.m. ***** BREAK III. Test Results and Analyses to 05 W. English, GE 10:00 - 11:fd a.m.
IV. Propose Criteria and Code Changes
@ S. Ranganath, GE 11:fD-11:45a.m.
11:45 - 12:00 Noon V. Discussion and Adjournment s-
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- f ATTACHMENT C tC
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LIST OF HANDOUTS i
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- 1. ' Piping and Fitting Dynamic Reliability Program - D. Guzy
- 2. Piping and Fitting Dyn'amic Reliability Program EPRI Introduction and Overview.- Sam W. Tagart, Jr.
- 3. Piping and Fitting Dynamic Reliability Program - Bill English Overall Program Structure, Objectives of Program, PFDR Test Programs
- 4. Potential Design Rule Changes - S. Ranganath, GE Nuclear Energy
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- - E. IGNE s'\'
- ACPS SUBCOMMITTEE MEETING ON STRUCTURAL NGINEERING I
LOCATION Culver City, California ,
DATE March 29h1988 ATTENDANCE LIST
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