ML19291A453
| ML19291A453 | |
| Person / Time | |
|---|---|
| Site: | San Onofre, Zion  |
| Issue date: | 04/13/1979 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Fraley R Advisory Committee on Reactor Safeguards |
| References | |
| NUDOCS 7905160043 | |
| Download: ML19291A453 (12) | |
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Raymond F. Fraley, Executive Director Advisory Conmittee on Reactor Safeguards h'ashington, D.C.
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Dear Mr. Fraley:
Your memorandu:n of October 11, 1978 forwarded Cc=aittee co:uents on our report of August 15, 1978, which reported on the then current status of resolution of a nu:nber of questions that the Com:aittee had asked during the period September 1977 through February 1978. A number of the Conmittee cc~ents appear to require no further action at this time.
For those ratters that are still open, the enclosure to this letter presents additional information.
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t Harold R. Denton, Director Office of Nuclear Reactor Regulation
Enclosure:
As Stated 4THis DOCUMEt4T CONTAl.tlS 5.k POOR QUAUTY PAGES 7905160093
7 m um. s c ui t 1.
Seismi_c_ Pe-eyalop tinn of San Onofre_l, The Con..aittee through its Plant Operations and San Oncfre Subcc::mittees is following the SEP and San Gnofre I seismic re-evaluation.
ACRS consultants and the San Onofre Subcomittee are reviewing the San Onofre site specific earthquake program.
Upon completion of their review, a decision on the future course of ACRS activities will he made.
Staff Response:
The seismic re-evaluation of San Onofre, Unit I has been integrated into the SEP.
The licensee had chosen to propose seismic input parameters for the seismic re-evaluation of important safety related structures, systems and components based on a Site Specific Earth-quake Model (SSEM) developed in its site specific earthquake program.
The staff and its consultants have reviewed the licensee's SSEM described in its May 1978 final report " Simulation of Earthquake Ground Motions for San Onofre huclear Generating Station, Unit 1".
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From this reciew specific areas were identified that need additional studies before the staff can make a determination on the acceptability of the site specific earthquake program.
The licensee is presently doing the additional studies relating to the intcgration of mesh size, slip functions and appropriateness of certain parameters presented in the May 1978 final report.
These studies are scheduled to be completed in the March-April time frame.
Concurrently, the staff is continuing the review of the site specific earthquake program with the assistance of its consultants.
Completian of the licensee's additional studies, and the staff's determination of acceptability of the SSEM program, along with other einpirical arguments, are significant milestones in the SEP review schedule that need to be accomplished for the seismic re-evaluation of San Onofre Unit 1 to proceed with the completion of the overall SEP by February 1981.
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Zion _ Operpting. E.xperience_
The Subcounittee on Plant Arrangenents plans to acet with the NPC staff on October 25, 1978 to review the tuo areas outstanding.
The future course of ACRS activity will be decided af ter that meeting.
Staff Response:
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The staff did ueet with the Plant Arrangements Subconnittee on 4
October 25, 1978. At the October 25, 1978 meeting, the licensee, l
Fluor Powe* Services and the staff discussed the Zion Station review with members of the subcommittee.
Based on our meetings with the licensee and the information contained in the June 16, 1978 rcport, we indicated that we believe that the objectives of the ACRS -
recommended review have been met and that although some corrective action is recommended, as discussed in the report, none are con-5 sidered to be of first order significance from the standpoint of reactor safety.
We therefore indicated to the Subcommittee members that we considered this item of the ACRS June 17, 1977 letter to be completed.
Backfi_t Review In its letter of June 17, 1977, the ACRS recommended that Commonwealth Edison Company review the Zion Station for possibly significant differences from current criteria and that the NPC staff evaluate this review and report to the ACRS its conclusion concern-ing possible backfitting requirements.
On November 10, 1977, we and the licensee met with the Zion Station ACRS Subcommittee to discuss the licensee's proposed plans with regard to the recon: mended review.
It was agreed that the review would involve the review of Zion Station against the Regulatory Guides and Standard Review Plans and that the Byron /Braidwood design would be used as the reference plant.
By letter dated September 12, 1978, the licensee sutn'ittcJ o report (datedJuly 20,1978) which suanarized the review cor.dum ceu by themselves and their consultant Sargent & Lundy Engineers.
The staff is presently reviewing this report and anticipates that additional information will be required from the licensees before we can make any conclusions with regard to any possible backfitting requirements.
3.
Evaluation of fiRC and EPRI Repor_ts__on !h an_ Enginyering_ in fluclear Plants The Subcom.nittee on Plant Arrangements plans to neet with the NRC staff in the near future to discuss these reports.
Staff Response:
The f1RC s tudy regarding human factors engineering in control rocms, conducted under contract with ferospace Corporation, has been corpleted.
The first phase of an EPRI sponsored study to review existing control room design, conducted by Lockheed Missiles and Space Division, also has been completed.
Phase II of the EPRI effort, now in progress, is ained at development of criteria for control room design.
The staff would be pleased to arrange for presentations by the contractors performing the studies and to meet with the Plant Arrangements Subcommittee to discuss these reports.
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Sei snl c_ De_s.i gn Ma rgi nf_ a t _"or t h /Inna_
i It appears that this information could be develop <:d by the liccnsee from existing seismic analysis without the "r'ajor effort" suggested by the licensee.
The Cocuittee will consider this matter further after receipt of the final report from the NRC staff as indicated in Mr. Case's letter of June 14, 1978.
Staff Response:
A draft of this report is currently under preparation.
It is anticipated that it can be coc>pleted by about June 1979.
Copies will be forwarded to the Coc'mittee '. shen they are available.
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Ccrggj]ugic.es of F_uel J i_f t-O f f i q EUR '_s, The ACRS looks forward to receipt of the Staf f's Sumary as indicated.
Staff Response:
The current best estimate completion date for the review of the potential for fuel lif t-of f is June 1979.
Our evaluation will include independent audit calculations of the potential for fuel bundle lif t-off considering the A-2 '.lorking Groups tiethodology for Cor:bining Loads.
'le will also evaluate two related General Electric Company's topical reports.
(EWR Fuel Channel fiechanical Design and Deflection, fiEDE-21354-P and B'c:R-6 Fuel Assembly, Evaluation of Corbined Safe Shutdcun Earthquake (SSE) and Loss of Coolant Accident (LOCA) Loadings, i;EDE-21175-P).
The probability for fuel bundle lif t-off appears sufficiently remotes therefore an evaluation of the consequences has not ' cen performed.
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S t ry tc_h_ Poper_
This issue has been resolved to the satisfaction of the Co.,aittee.
Staff Response:
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Regional Tectonics of the Paci fic f;ortiraest The Comaittee does not believe these studies have been closed out, for exanple, work is continuing in connection with the Skagit review, and the Office of Research has initiated a program on this subject.
The Comiittee would like to be kept informed of significant develop-ments as they occur.
Staff Response:
With respect to the Skagit review, Puget Sound Power & Light r.ompany will soon submit a substantial package of additional seismic infor-mation.
This material will be revicued by the Staff and by the USGS when it arrives.
The Staff will provide the Committee with information concerning the status of this review as it proceeds.
The Office of Research studies in the Pacific florthwest are limited to a contract with Teledyne Geotech Corporation co-funded by the U.S.
Army Corps of Engineers.
The purpose of this program is to analyze seismograms writtun for the Department of Defense by their Long Range
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Seismic Monitorh,; Stations from 1962 to mid-1965.
These records were made by highly sensitive, relatively densely deployed instruments, but never checked for local activity which was actually regarded as noise by the original observers.
The records are equivalent to three-and-one-half years of data recorded by a local network specifically emplaced to monitor local activity, and, as such, are available to us at a fraction of the usual cost.
The final report is due at the end of this quarter and will contain a list of the earthquakes, giving their locations and magnitudes and relating them to the gross tectonic regime. A compari-son with historical seismicity will be made to demonstrate the degree of stationarity over time and with respect to the entire magnitude range.
Preliminary results indicate very well defined seismic zones and lineations that mirror the historical trends.
In addition, some new areas of activity have emerged.
On September 28-29, 1978 the Staff met with geophysicists at the University of Uashington and with representatives of the Oregon and Washington State Geological Surveys and a representative from the University of Oregon in Portland, Oregon.
flRC interests in seismic studies and the identification of tectonic and geologic features which could be corre-lated with seismic activity or characterized as susceptible to earth-quake activity were outlined in detail.
. The discussions i.ere keyed to making them aware of special problems faced by the NRC and to an effort to discern their degree of interest and their general capability in the area of geophysical investigation.
At present, we are awaiting the results of our discussion.
Informal notification has been received that proposals addressing various aspects of our problem are in preparation by both Universities.
A proposal was received from the state geologists and, after critical review, a meeting was convened among the proposers and the Staff.
The proposal was deemed generally inappropriate, and after the discussion the proposer; agreed to reconsider their approach and possibly submit an amended proposal.
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p_ C Coo _k_, Un i t 2_,
0pp ra t_i n_g_ Expe r i enc e The Comaittee looks forward to a report on D C Ccok Unit 2 APDMS performance and ECCS reliability in March 1979.
lio..ever, the Conaittee would appreciate an early response to Dr. Isbin's request for infor, nation on gan:na irradiation tests. This request was forwarded to the f1RC staff by rnemorandum from G. R. Quittschreiber on July 10, 1978, a
Staff Response:
Dr. Isbin's request for information on gai na irradiation tests was responded to by a note dated January 3,1979 from M. M1ynczak to G. Quittschreiber.
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9.
Vulnerabili ty_of_ _Syste as_ V_i tal_ t o S afe Shu tdov,n_
1 This item was discussed during the Security portion of the review of the Yellow Creek plant (January 1978).
The inquiry. lated to the ability of all systems needed to achieve and maintain safe i
shutdown to perform their intended function in the face of a I
variety of disruptive events including sabotage.
Mr. Vassallo sdid that the matter was being s'udied and that he would provide the ACRS with a schedule for resolution.
l Staff Response:
i The ability of systems needed to achieve and.Laintain safe shutdown to perform their intended function in the face of a variety of dis-ruptive events, including sabotage, is addressed by two research programs:
1.
In July 1977 NRR requested a research program to investigate various plant design alternatives for their potential to increase protection against sabotage.
This study is part of Task Action Plan A-29.
This research contract has been awarded to SANDIA, and the initial phase of the work, i.e.,
facility characterization is underway.
Preliminary results of the first phase of the work are scheduled for October 1979.
This program and its status is described in greater detail in the Decenber 4,1978 update of the Status of Generic ACRS Concerns.
2.
On February 24, 1978 NRR and SD requested that RES initiate a research program to evaluate alternative provisions for assuring the safe shutdown and cooldown functions of reactor plants under conditions other than normal operation or design basis accidents.
The events to be considered in this study include loss of AC and DC power, fire inside and/or outside containment, control room damage, aircraf t crash, and off-site explosions.
This study is not intended to address plant security but close coordination between this study and the sabotage study described above will be maintained. A work statement and proposed schedule for this research program is under developnent.
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Combining Seismic and Other Abnornal L oads in the Dnign of Nuclear Plants The formation of a task force to study and develop recer mendations on combining seismic and other loads is a step in the right direc-tion.
The Co:wittee would like to be informed of the schedule for completion of this work.
Staff Response:
The method of combination of leads is being addressed in a number of current staff technical activities, including B'.-lR containment loads (TAPS A-7, A-8, and A-39) and aspmetric blowiown loads on the reactor coolant system and other safety-related equipment (TAP A-2).
These activities include consideration of the combina-tion of various accident loads (e.g., LOCA discharge loads plus suppression pool dynamic loads), combination of accident loads and earthquake loads (SSE), and conbination of operational loads (e.g., SRV discharge) with anticioated earthquate loads (OBE).
The working group formed by the Directors of DSS and DOR met I
during the summer of 1978 and issued the report NUREG-0484
" Methodology for Combining Dynamic Responses." The group recommended use of the SRSS method of combining dynamic responses to SSE and LOCA loads.
The Director of NRR has approved use of this interim position in licensing activities related to TAPS A-7, A-8, A-39 and A-2.
I The report has been provided to the ACRS Fluid Dynamics Subcom-mittee and was discussed at its November 26 to 28 neeting on the Mark II containment program (A-8 and A-39) and the licensing review of the three lead MK II Bt:Rs (Zinmer, laSalle, Shoreham).
The MK II owners group has also asked NRR to consider extension of its approval of SRSS nethodology to the case of combined OBE and Safety Relief Valve loads.
This is a case of loads which ccmbine under " abnormal, rather than accident" conditions.
We expect to reach a decision on this matter in early February 1979 for use in the MK II review and for dynanic qualifications of safety equipment. He expect to review the decision with the Fluid Dynamics Subcommittee.
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