ML20035E057
| ML20035E057 | |
| Person / Time | |
|---|---|
| Issue date: | 08/05/1992 |
| From: | Wylie C Advisory Committee on Reactor Safeguards |
| To: | Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-2829, NUDOCS 9304140225 | |
| Download: ML20035E057 (16) | |
Text
hbbN~0$h CERTIFIED BY:
DATE ISSUED:
7/15/9'f C. WYI,IE - 8/5/92 PM %!9M3
SUMMARY
HIGHLIGHTS / MINUTES OF THE ACRS i
SUBCOMMITTEE ON IMPROVED LIGHT WATER REACTORS MEETING i
JUNE 18, 1992 BETHESDA, MARYLAND INTRODUCTION t
The ACRS Subcommittee on Improved Light Water Reactors met on June 18, 1992, at 7920 Norfolk Avenue, Bethesda, Maryland, to continue its review of the Final Safety Evaluation Report (FSER) of the
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EPRI's Requirements Document for the evolutionary designs.
There were no written or oral statements received or presented from
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members of the public at the meeting.
The entire meeting was held in open session.
E.
G.
Igne was the cognizant ACRS staff member l
for the meeting.
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Attendees i
Principal meeting attendees were as follows:
ACRS C. Wylie, Chairman C. Michelson J.
Carroll D. Ward T. Kress P.
Davis, ACRS Consultant
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Presenters J. Wilson, NRR E. Whitaker, EPRI E. Rumble, EPRI B.
Pusheck, EPRI J.
Yedidia, EPRI K. Whitaker, EPRI i
i NRC Staff
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R. Van Houten H. Bailey l
l' J. Wigginton R. J.
Dube R.
Pierson D. Smith C. McCracken D. Thatcher P. Kruzic T. Kenyon i
EPRI Others J. Trotten D.
Strawson, MPR G.
Buckhold E.
Swanson, BWNS 4
T. Marston R. Schumaker, BWNS l
P. Giovanni A. Beard, Halliburton NUS V.
San Angelo, Bechtel Power Corp.
i S. Additon, TENERA i
r.
h ~ * ~ ~ ^ *
- b
-R, PDR l
I r .l l l Improved LWR Subcommittee 2 l Meeting - June 18, 1992 l l Openino Remarks j The meeting was convened and the opening statement read by Mr. C. l Wylie, Chairman of the ACRS Subccmmittee on Improved Light Water l. Reactors, at 8:30 a.m. The Chairman, and other members of the i a t l Subcommittee did not at this time, have any prepared comments / { f statement regarding the meeting or the agenda. ) l 1. Status and Overview - J. Wilson, NRR i i l Mr. J. Wilson is the project manager at NRR for the EPRI ALWR l l Requirements Documents for Evolutionary Plants project. He l ll stated that his introductory remarks are similar to the ones I ) he made yesterday, June 17, 1992, on this same subject, except l the purpose of today's meeting is to discuss Chapters 2 - 13 [ s of the EPRI evolutionary requirements document and the staff's i I review of the document. He indicated that the staff is seeking ACRS comments on the evolutionary requirements j document and on the staff's SER and request that ACRS comments I ~ be provided in July 1992 in order to support the staff's l, planned issuance of NUREG-1242 (Final SER for EPRI Evolution- [ a f ary Requirements Document) in August 1992. 3 i j In reply to a question by Mr. D. Ward, Mr. Wilson stated that I l the staff was not performing a regulatory compliance review ) nor a design review, but based on the submitted requirements 3 document the staff judged whether the existing regulations would be met with the proposed EPRI design or where misinter-l l pretation of an EPRI requirement is possible. Based on the SRP for guidance and the level of detail presented by the EPRI f requirements documerts, the staff assumed that all current regulatory requirements would be met by a design that complied I 3 with the EPRI ALWR Requirements Documents except when specif1-J s cally noted in the SER. Further, Mr. Wilson stated that the l i 5
s 4 Improved LWR Subcommittee 3 Meeting - June 18, 1992 t requirements document does not have legal or regulatory statu's, but serves as a vehicle to obtain consistent resolu-i tion of common operating plant problems, and is not intended l to replace the staff's review of future design specific j certification application. 2. Chapter 2. Power Generation System and Chanter 13. Main Turbine Generator System - E. Rumble, EPRI l l i Mr. E. Rumble stated that there are no controversial technical l problems with Chapter 2, although dialogue with the staff is i needed on some vendors specific items, e.g., flow capacity of l the turbine bypass valve, attachment loads for safety and 1 1 relief valves and condensate makeup system raw water pretreat-ment. With respect to load rejection, Mr. Rumble stated that PWRs require 100 percent while BWRs require 40 percent capability. In a PWR, a reactor trip will not actuate the h PORV of the steam generator, or cause lifting of the pressur-izer safety valves during a turbine trip. A 100 porcent bypass capability cost-benefit study was performed on a BWR and found that it was not warranted. In reply to a question by Mr. J. Carroll, Mr. Rumble stated that if a utility wanted 100 percent bypass capability in a BWR plant the design basis certificate needs to be changed. In a reply to a question by Mr. C. Michelson, EPRI agreed to add valve operability j requirements, especially during blowdown conditions, on the main steam isolation and the reactor water cleanup valves of j BWR power plants, } l i On Chapter 13, Mr. Ruble stated that only vendor issues remains. Of these issues Mr. Ruble mentioned three items that needs further dialogue with the staff, namely, 60-year design life of the main turbine-generator, need for prototypical i P r
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t i Improved LWR Subcommittee 4 3 Meeting - June 18, 1992 s testing and turbine missiles. Mr. Wilson stated that with respect to these issues, the staff accepts EPRI's commitment I to meet the applicable requirements, but that the staff needs g to verify compliance during the FDA/DC review. f,] l t 3. Chapter 3. Reactor Coolant System and Reactor Non Safety l Auxiliary Systems and Chapter 4. Reactor Systems - J. Yedidia, EPRI Mr. J. Yedidia presented the SER status of chapter 3. There t are no open issues, no confirmatory issues (except one which 4 I was included as a vendor-specific issue) and three vendor specific issues. Mr. Yedidia stated that more dialogue with the staff is needed on the chemical and volume control system j (CVCS). He stated that the staff's position is not clear. ] The staff agrees that for evolutionary plants the CVCS could j be considered as an auxiliary system that provides non-safety grade function, but since this system is required to function [ under adverse post-accident conditions the staff will need to { review individual applications during the FDA/DC review to j S verify compliance. The staff expert was not present to address this concern. l ( l Mr. Yedidia next discussed the Post Accident Sampling System j ) (PASS) issue. This matter was discussed before and was a subject on a recent ACRS letter. Mr. T. Kenyon, NRR, in reply to Mr. Carroll's question on the status of the ACRS letter on a the PASS concern stated that the staff is still drafting a response. On Chapter 4, Mr. Yedidia, stated that all open issues are closed except for two vendor-specific issues. There are no open confirmatory issues and the FSER has seven vendor
i Improved LWR Subcommittee 5 i Meeting - June 18, 1992 specific issues. Of these vendor specific issues Mr. Yedidia state'd that these could be simply resolved. In response to a question by Mr. C. Michelson, Mr. Yedidia stated that they will check Section 6 of Chapter 3 in order to resolve the r matter of reactor vessel level instrumentation for both PWR i I and BWR plants. r 4. Chapter 5. Encineered Safety Systems - E. Whitaker, EPRI. i Mr. E. Whitaker stated that this chapter is a continuation of yesterday's (ACRS Subcommittee meeting of June 17, 1992) discussion of Chapter 1, Section 2. This chapter discusses the basic three levels of protection, e.g., accident resis-
- tance, core damage prevention and mitigation.
The key requirements for the ESS are as follows: core damage probability of, 1x10-5, e whole body dose, 25 rem at 0.5 mile for events with a i cumulative frequency of 1x10-6, e no fuel damage for a double-ended pipe break up to 6 inches in diameter, and severe accident protection. e Mr. Whitaker indicated that this chapter seems to have the most areas of concern. He stated that many of these concerns can be simply resolved with the staff. Of major concern is the classification of BWR containment spray systems. EPRI claims that the staff review is based on earlier BWR design 1 and that the URD minimize bypass leakage, therefore, the containment spray core can be classified as non-safety grade. l
9 1 i l Improved LWR Subcommittee 6 Meeting - June 18, 1992 1 i With respect to passive plant Mr. Whitaker stated that containment sprays would complicate the design because an accumulator system would be needed and besides, EPRI believes that no containment sprays are needed. Mr. McCracken, NRR, stated that the issue has not yet been resolved. He stated 1 that the values proposed for bypass leakage is too low and probably difficult to achieve. Therefore, the staff feels that based on past experience sufficient design margins does not exist in the requirements document and the use of contain-ment sprays should provide more than adequate design margins even accounting for design uncertainties. In reply to a question by Mr. Ward, on whether to have a spray or should the spray be classified as safety grade, Mr. Whitaker stated that two divisions of sprays are provided for in the requirement documents -- the question is whether they need to be safety grade. Mr. Buckhold, EPRI, stated that the i design requirements for safety grade vs. non-safety grade systems are vastly different, i.e., QA, surveillance, environ-i ment (seismic), redundancy, tech. spec., etc., but the designs are similar. He believes that the issue of safety design requirements can be addressed without containment sprays, but as an added safety margin the ABWR and SBWR have non-safety i grade sprays. i i 4 Mr. Whitaker next discussed core debris coolability. The staff does not agree with the value for potential core debris spreading of 0.02 sq. m./MWt. It was stated that the staff would make a later determination of what adequate spreading value they would accept, although Mr. Whitaker felt comfort-able with_the value of 0.02. In response to a question by Mr. Ward, Mr. Whitaker stated that previous discussions with f the staff indicated that the 0.02 value seems to be i
^ Improved LWR Subcommittee 7 Meeting - June 18, 1992 except for the question of uncertainty. satisfactory Mr. W'ard expressed some concerns about the experimental and analytical bases for the 0.02 value. Mr. Wylie suggested that this matter be discussed as an agenda item during the ACRS July 1992 meeting. i Mr. Davis, ACRS Consultant, questioned the requirement'of a whole body dose of less than 25 rom at 0.5 mile for events with a cumulative frequency of 1x10-6. Mr. Whitaker stated that this requirement attempts to limit the frequency of large release. Mr. Davis is concerned that a high energy plume release from the containment could bypass a near-site popula-tion and still have an extremely large release. Mr. Carroll suggested that this concern be discussed at the July 1992 ACRS meeting. Mr. Michelson stated that the RCIC and RWCU valves i should be operable under pipe break conditions. Mr. Trotten of EPRI, agrees and words to that effect will be added to the a i document. Further, it was mentioned that the staff is still evaluating the question of whether alternate AC power sources under limited condition of operations will be given credit. Before credit can be give, the staff stated that it must resolve the surveillance changes in the technical specifica-tions and consider external events that are most likely to cause loss of offsite power. l Mr. S. Additon, TENERA, clarified the matter of the 0.02 l square meter /MWt core debris spreading value. Mr. Additon S stated that the.02 value is based on water boiling on top of the debris, and that the debris would be in a coolable configuration. The debris is assumed to spread - and the empirical basis for the expected core debris spreading is ] addressed in a report submitted in conjunction with the evolution plant requirements document. (DOE /ID-10278,
Improved LWR Subcommittee 8 Meeting - June 18, 1992 " Technical Support for the Debris Coolability Requirements for ALWR in the Utility /EPRI LWR Requirements Document," by Fauske & Asso., Inc., dated June 1990.) In reply to a question by Mr. Carroll, Mr. Additon stated that if the GE-ABWR water flooding is activated by a thermal fuse while in the CE design, he believes that a manual system is used. Require-ments are written so that flooding would not wet the bottom of the reactor vessel. Ex-vessel steam explosion loads were also accounted for in the design. 5. Chapter 6. Buildino Desion and Arrancement - B. Pusheck, EPRI. Mr. B. Pusheck presented a brief overview of the building design and arrangement requirements and discussed Chapter 6 SER status. He felt that continuing dialogue with the staff is necessary in order to resolve certain issues on a generic basis rather then as a vendor specific issue. Some issues are the inspection of potential structural degradation of safety t related structures, e.g., inspection of the exterior stee) shell of the containment, degradation of intake structure and interactions between safety related structures and non-safety structural foundations. EPRI agrees with the staff's concern and believe it thould be resolved generically instead of I vendor specific issuts. The staff feels that many of these issues could be handled generically. Mr. Pusheck pointed out that the SER nisstates the design provision that the cask pit bottom will be designed to accommodate a spent fuel cask drop accident. This is an incorrect statement. The URD specifies two alternatives; (1) to separate the cask pit from the spent fuel, pool, so that when the cask is lowered and accidently dropped any damage to the pit locally will not permit draining of the spent fuel l I
Improved LWR Subcommittee 10 Meeting - June 18, 1992 7. Chanter 8. Plant Coolina System - J. Yedidia, EPRI. Mr. J. Yedidia presented a brief overview of the plant cooling water systems and the SER status of Chapter 8. All the icsues in this chapter is either closed or being resolved satisfacto-rily. Mr. Michelson requested that EPRI provide at the July 1992 ACRS meeting information regarding the need for a single f failure requirement in trying to isolate the ultimate heat sink to prevent building flooding. 8. The Pole of the Utility Reauirements Document - T. Marston, EPRI. Mr. T. Marston requested that he would like to address the Subcommittee in place of Ed Kintner, EPRI, who is not able to be here today because of conflicting schedule. Mr. Marston stated that it was important to keep in perspective the role of the utility requirements document. In a survey about ten years ago, the utilities were asked of its needs for the next i ~eneration of nuclear power plants. The results were that utilities wanted simplified plants with increased margin of safety in order to assure protection of investors. The other P major factor found in the survey that may prevent utilities from considering the nuclear option in the future is the lack of regulatory stability. In this area, the early resolution of generic / safety issues in the utility requirement document is a major step in promoting regulatory stability. Standard-ization also plays an important role in a utility decision in considering the nuclear option. Mr. Marston stated that recent survey indicates that over 80 percent of the nuclear utilities will be installing or planning to install baseload capacity and the type of power i
i Improved LWR Subcommittee 11 Meeting - June 18, 1992 plant chosen has to be attractive not only from the financial perspectives, but also from a risk perspective. He emphasized the need to resolve the generic issues now in order to make the nuclear option more attractive to the utilities. He i mentioned a recent economic study that shows that the ALWR, is "in-the-running," but is certainly not a leader. It was mentioned that the staff may be having a difficult problem in resolving generic issues for both operating and future plants together because it is being done in parallel. Mr. Marston feels that this may not be the proper solution as it may compromise the overall process. Mr. Carroll suggested that the staff discuss the matter of resolution of generic i issue during the July 1992 ACRS meeting. Mr. Marston in closing, stated that he hopes the resolution of generic issues [ does not vary f rom plant-to-plant. Mr. McCracken of the staff l 1 agrees. 9. Chapter 9, Site Support Systens - B. Pusheck, EPRI. 4 j j Mr. B. Pusheck, presented a brief review of the site support I systems and provided the SER status on Chapter 9. All open l issues are closed as well as confirmatory issues. There are 13 utility-specific issues. Some of these utility-specific issues according to Mr. Pusheck should have a generic closure or discussed further with the staff to consider the generic 4 implications. j The staff states that fire protection for redundant shutdown systems in the containment should ensure that one shutdown j division will be free of fire damage. This can be achieved by the use of labyrinths inside containment to provide separa-tion, and that "line-of-sight" separation by distance is not [
i Improved LWR Subcommittee 12 Meeting - June 18, 1992 permitted. The industry position is that redundant shutdown f syste'ms inside the containment are excluded from the barrier l separation requirement and that fire protection inside the containment are accomplished by (1) spatial separation, (2) i limit combustible loading, and (3) detection and suppression systems. Complete separation for redundant shutdown systems outside the containment is provided. j Mr. McCracken stated that EPRI has misinterpreted the SER. The staff does not prohibit spatial separation in the contain-ment, although the staff will review each design on a case-by- [ t case basis. I Mr. Pusheck stated that the other issue is also related to the fire protection system. The staff recommends that consider-I ation should be given to " safety-grade provisions for fire protection systems to assure that shutdown capabilities are protected." The industry states that the ALWR requires designs to comply with all current regulatory requirements including additional guidance for fire barriers (outside j containment) and prevention of smoke and toxic gas migration. The industry further states that safety-grade fire protection system is a new requirement and should be identified as a new l l policy issue. Mr. Michelson asked whether or not it is credible to have a fire during an earthquake. If there are no fires during an [ earthquake, then seismically qualified fire protection system f is not needed. If you postulate a fire concurrent with an I earthquake, then enough fire protection capability to address f f that assumption is required. The water supply must be maintained after an earthquake. Mr. Pusheck stated the l provisions are available to deal with fires caused by earth-
- ~ Improved LWR Subcommittee 13 Meeting - June 18, 1992 quake. Mr. Pusheck stated that more dialogue with the staff is ne'eded to clarify the issue. 3 10. Chapter 10. Man-Machine Interface Systems and Chanter 11. Electrical Power Systems - E. Rumble, EPRI. Mr. Rumble stated that the objective is to take advantage of the gains in the man-machine interface system experience gained since plant have been licensed. He stated that there are three policy issues in Chapter 10. They are the digital control diversity for alternate shutdown, testing and surveil-lance, and reliable control room annunciators. i With respect to the diversity issue, Mr. Rumble stated that EPRI is in agreement with the there are no open issues staff, although it was pointed out the GE is still having dialogue with the staff on this matter. On testing and surveillance, and reliable control room annunciators, Mr. Rumble stated that our position is similar to the staff's. r On Chapter 11, Electrical Power Systems, Mr. Rumble discussed three utility-specific items, namely, load capability of the combustion turbine generator, power rating of the emergency diesel generator and design of lighting systems. In addition he discussed one policy issue, alternate power source to non-safety loads evolutionary plants. Mr. Rumble stated that of the three issues, he believes that' the design of lighting system is the most important. The staff requires that at least a portion of the continuous ac lighting systems in safety-related areas outside main control i i
t 3 Improved LWR Subcommittee 14 l Meeting - June 18, 1992 room and access route to these areas, should be provided from a Cla'ss 1E distribution system capable of being powered from a Class 1E diesel generator. Mr. Rumble states that this is j adding new requirements. Mr. Rumble indicated that he is I concerned about the increasing cost of the 1E systems and more administration work associated with technical specifications. This issue is still being resolved with the staff. f Mr. Rumble next discussed the policy issue that appears in Chapter 11. NRC will require that an evolutionary ALWR design I should include an alternate power source to the non-safety i loads -- unless the design can demonstrate that the design [ t margins in the evolutionary ALWR will result in transients for a loss of non-safety power event that are more severe then s ] those associated with the turbine-trip-only event in current j existing plant design. i i The staff has reviewed EPRI's plans to provide an alternate power source and found that EPRI's proposed requirement minimally satisfies the staff requirement -- and is accept- ] able. ] Before concluding the meeting, Mr. Michelson requested that Mr. Ruble comment on associated circuits at the July 1992 ACRS meeting. t Regarding Chapter 12 on Radioactive Waste Processing Systems, I Mr. Trotter, EPRI stated that there were no points of dis-f agreements, other than the HEPA filters which were discussed briefly at yesterday's meeting (June 17, 1992). The meeting was concluded at 3:05 p.m. 1 d a
Improved LWR Subcommittee 15 Meeting - June 18, 1992 Subcommittee Action / Future Plans The Subcommittee in its deliberations plans to refer this matter to the full Committee during the July 1992 ACRS meeting. Summary of Acreements. Assianments. Recuests. and Follow-up Matters The following agreements, assignments, requests and follow-up matters were the results of the meeting: The information on material selection on the ALWR should be sent to Dr. P. Shewmon for his review. His comments, if any, will be discussed at the July 1992 ACRS meeting. (Follow-up E. Igne) e T. Kress requested that we obtain a report from.S. Additon, 2 TENERA, on the technical basis for 0.02M /MWt value for core debris spreading. (Follow-up E. Igne) The following items should be discussed at the July 1992 ACRS e meeting. 2 basis for the 0.02 M /MWt value for core debris spreading clarification of the 25 REM 9 0.5 mile requirement I staff concerns of GI-82, Beyond the design basis accident: of the Spent Fuel Pool. l describe the handling of shield plug, etc., at the. spent fuel pool and the requirements of the lifting rig i I 5 ,t
Improved LWR Subcommittee 16 Meeting - June 18, 1992 the application of single failure criteria with respect 'to the ultimate heat sink and its potential to cause building flooding philosophy on the resolution of generic issues on operating and advance plant concurrently discussion on the use of associated circuits discuss technical specification requirements on shutdown risk for passive plants i Anoendix e List of attendees Annotated copy of agenda e List of Documents provided to the Subcommittee r e EPRI ALWR Utility Requirements Document, Evolutionary Plant, Vol. I, Chapters 1-13, April 1992 Revision EPRI ALWR Utility Requirements Docament, Passive Plant, Vol. III, Chapters 1-13, May 1992 Revision EPRI ALWR Utility Requirement Document, Overall Require-ments, Chapters 1-13, June 1986 NOTE: Additional meeting details can be obtained from a transcript of this meeting available in the NRC Public Document Room, 2120 L Street, N.W. Washington, D.C. 1 20006, (202) 634-3273 or can be purchased from Ann Riley and Associates, LTD., 1612 K Street, N.W., Suite 300, Washington D.C. 20006, (202) 292-3950.
[7t&Sb 2 f'.'})Q )~~ & 9) ' JSf tE'55 1c scro,w o }, vct E E # a t Mg ~'.),'o Thursday, h \\ ~ ue 18.1992 q 8:30-8:35 C. Wylie Introduction ~ 8M - J. Wilson Chapters 2 - 13 SERs 8:45 - 9i30 E. Rumble Chapters 2 and 13 9:30 -10:30 J. Yedidia Chapters 3 and 4 10:30-10:45 BREAK 10:45 -11:45 E. Whitaker Chapter 5 11:45-12:30 B. Pusheck Chapter 6 12:30 -1:30 LUNCH 1:30 00 K. Whitaker Chapter 7 2 00- 2:30 J. Yedidia Chapter 8 2:30 - 3:00 B. Pusheck Chapter 9 3:00 -3:15 BREAK 3:15 - 4:45 4 :$$ E. Rumble Chapters 10 and 11 -445 6 C. Wylie Concluding Remarks 320-595 l k .f i t i i f i .i i .}}