ML20083B941

Forwards for Info,Notes Taken by W During 950505 NRC Senior Mgt Meeting

ML20083B941
Person / Time
Site:	05200003
Issue date:	05/05/1995
From:	Mclntyre B WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9505150011
Download: ML20083B941 (7)

Text

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WOStinghouse Energy Systems Box 355 Pittsburgh Pemsylvania 15230-0355 Electric Corporation DCP/NRC0318 Docket No.: STN-52-003 May 5,1995 Document Control Desk I

l U.S. Nuclear Regulatory Commission l

Washington, D.C. 20555 l

A'ITENTION:

KRISTINE SHEMBARGER I

SUBJECT:

NOTES FROM THE MAY 3,1995 SENIOR MANAGEMENT MEETING

Dear Ms. Shembarger:

Attached for your information and use aie the notes taken by Westinghouse during the May 3,1995 Westinghouse /NRC Senior Management meeting.

Please contact me if you have any questions concerning these notes.

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n Brian A. McIntyre Manager Advanced Plant Safety and Licensing

/nja Attachment ec:

T. J. Kenyon NRC 9505150011 950505

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t SENIOR MANAGEMENT MEETING May 3,1995 STATUS OF ACTIONS FROM LAST MEETING Bill Russell reemphasized the importance of developing an action items list at the end of each meeting and beginning the next meeting with a status of unfinished actions.

1. Action All:

NRC and Westinghouse to develop and maintain a list of actions from senior management meetin;;s. The list of unfinished actions will be the focus of the meetings.

DISCUSSION ON STAFF RESOURCE PROJECTIONS i

Mike Case (NRC) presented resource projections for the AP600 review. The NRC projects that 79 thousand l

hours of direct effort will be required during the FSER phase of the AP600 review. This projection is based in part on the experience with the ABWR and System 80+ reviews (67.3 thousand and 61.2 thousand respectively). Mike Case noted that external forces affecting resources are 1) focus shifting to operating plants, 2) overall resources declining,3) competition for resources increasing and 4) advanced reactor resources less interchangeable.

Bill Russell indicated that technical review sections that have been previously dedicated to advanced plant reviews are being re-assigned to operating plant issues. He emphasized that the resources to perform the l

AP600 review are available now but if the schedule is delayed and those resources are reassigned to operating plants they will not be pulled back. Critical branches are PRA, containment, severe accidents, and l

Chapter 15 review areas.

Bob Vijuk indicated that Westinghouse could provide phased submittals--areas where we have partially complete reports (for example, test reports).

Bill Russell recognized the value of creatively addressing the resource issue.

Bill Russell emphasized that the staff requires actual SSAR revisions in order to provide FSER input (letters or draft input are not sufficient, based on the lessons learned from CE and GE cfforts).

2. Action All:

NRC and Westinghouse to develop actions to address resource issues discussed at 5/3/95 Senior Management Meeting.

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3. Action W:

Westinghouse to identify areas where phased submittals can be provided (and schedule) to support scheduled review activities.

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LEAK HEFORE HREAK Ashok Thadani indicated that the staff is reevaluating their position on leak-before-break for AP600 and will inform Westinghouse of the results of the reevaluation upon completion.

The Westinghouse presentation emphasized the need for providing Hexibility in trading off piping supports to limit normal stresses versus pipe whip / jet shields for maximum stresses. Bill Russell and Goutam Bagchi indicated that to provide this Dexibility may require additional audits and possibly parametric studies.

4. Action N:

NRC to schedule internal meeting to firm up position before May 5. NRC to inform Westinghouse of revised position on LHB at earliest possible date.

RADIOLOGICAL CONSEOUENCES Westinghouse provided a presentation on the AP600 containment design and radiological calculations. Key points in the presentation were 1) The AP600 containment design is robust,2) the AP600 pressure transient is similar to existing operating plants (containment pressure at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is lower than some currently operating plants),3) margin has been designed into the AP600 containment,4) the containment is designed to mitigate activity releases to the environment and 5) the calculated LOCA dose is reasonable and can be i

shown to meet the appropriate, c limits with margin.

Bill Russell indicated that his concern is beyond the short term containment response (beyond 24 or even 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />). Bill Russell referred to an event at Braidwood where containment connections were open except for i

bottom covers, potentially permitting containment bypass, for an entire cycle due to operator error (the particular connections were for hydrogen sensors, which for AP600 are within containment). Bill Russell noted that he is looking for containment pressure at 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and 30 days.

During followup discussion on dose calculations Jim Grover indicated that his presentation used the low volatile releases directly from NUREG 1465.

The controlling issue in the dose calculations is the lambda values based on the thermal hydraulics inside containment and the resulting aerosol removal processes.

Bill Russell asked if Westinghouse had looked at other accident management techniques to stop long term radiological releases. In response, it was noted that in the long term period of interest that there are essentially no aerosols left, signifiantly reducing the dose effects of any containment leakage. Bob Vijuk indicated that Westinghouse could provide some long term calculations using the fan coolers but the benefit will be small. Westinghouse discuwed the results of an evaluation of a 200 ppm spray system located at the polar crane elevation, noting that the calculated dose bene 6ts were very small. Westinghouse discussed the possibility of using the fire protection system as a source of spray water but that the system would not necessarily be located at the top of containment.

Ashok Thadani indicated that the fire system possibility is in line with what the NRC is looking for and that the NRC is not looking for an automatic system.

Jack Kudrick note <l that the staff has a number of questions relative to the aerosol removal integrated with

' the containment thermal hydraulic response.

The NRC's main concern is extended containment pressure (long-term) issue and the potential for leakage

through containment penetrations. The NRC noted that the language in the proposed revision to 10CFR100 allows the NRC some flexibility in DBA dose calculations when consideration is given for " enhanced mitigation features" such as a nonsafety spray system used to reduce long term containment pressure.

Bill Russell discussed the NRC philosophy for calculating DBA doses in the past using a lot of inherent conservatisms. In the AP600 review, the NRC is willing to consider an integrated approach that balances uncertainties in DBA dose calculations against the benefits provided by additional features (not necessarily safety-related features). The focus for these features is on capability, availability and reliability.

Westinghouse agreed to investigate long term mitigation strategies using additional external water, fan coolers, or an internal spray system at expected and off normal (stratified) containment conditions.

it was agreed that interactions need to be accelerated between Westinghouse and NRC on DBA calculations.

5. Action W:

Westinghouse to provide containment pressure curves out to 30 days.

6. Action W:

Westinghouse to evaluate the possible long term pressure / radiological mitigation options and provide benefits. Also look at effect of sprays in penetration areas.

Consideration of features and the DBA analysis to be provided in July. A schedule for completion to be provided during the week of May 8,1995.

7. Action All:

Westinghouse (Grover) and NRC (Lee) to meet in Pittsburgh to discuss DBA source term calculations with next two weeks.

SECURITY A short discussion on the current status of the review was provided. Westinghouse /NRC status and understanding of issue are consistent.

INITI AI, TEST PROGRAM A short discussion on the current status of the review was provided. Westinghouse /NRC status and understanding of issue are consistent. Ashok Thadani stated that he is looking for a schedule for submittal of Chapter 14 actions / revisions. It was noted that the schedule is dependent on ITAAC revision process.

l Submittals will occur when the test abstracts are available.

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t Bob Vijuk emphasized the need to utilize the benefits of design certification testing and analysis using i

validated codes and not to unnecessarily run full-scale tests or, the actual constructed plants.

It was agreed that further progress on key technical issues should not wait for completion of ITAACs. The potential differences in position need to be resolved soon. The dialogue should begin before the end of May.

8. Action W:

Westinghouse to address NRC comments on initial test program that focus on what

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could be hard spots in test scope by the end of May.

I.

PASSIVE SYSTEMS RELIABILITY The NRC (Butcher) indicated that NRC and Westinghouse have agreed upon an approach. Agreement on specific tasks will allow for agreement on the specific resolution. Westinghouse and NRC met immediately following the meeting to review the schedule milestones.

TECIINICAL SPECIFICATIONS The NRC presentation noted that Westinghouse intends to propose criteria to optimize Technical Specification Completion Times (CT's) and Surveillance Frequencies (SFs). The criteria would consider design basis, transient and T/li anulyses; PRA sensitivity analyses; and reasonable repair requirements based on licensee inputs. It is intended that Westinghouse and NRC staff will agree on the criteria before Westinghouse proposes specific cts and SFs.

9. Action W:

Westinghouse to provide completion time / surveillance interval criteria to staff during the week of May 8,1995.

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RTNSS A short discussion on the current status of the review was provided. Westinghouse /NRC status and understanding of issue are consistent.

ADVERSE SYSTEMS INTERACTIONS 1

A short discussion on the current status of the review was provided. Westinghouse /NRC status and understanding of issue are consistent. A report on ASI is to be provided by Westinghouse in June,1995.

l POST-72 IIOUR SUPPORT ACTIONS A meeting between Westinghouse and NRC staff on post-72 hour support actions was held on April 27, 1995. The NRC has not accepted the Westinghouse positions for the AP600. Tim Collins referred to the list of Reactor System Branch meeting open items (Hsii issues) as examples of issues that needs to be addressed.

10. Action W:

Westinghouse to review RSB meeting open items on post-72 hour support actions (IIsil issues) and indicate where clarification from NRC is needed.

11. Action N:

NRC to issue any additional questions on post-72 hour support actions.

~ CONTAINNIENT PERFORNIANCE A short discussion on the current status of the review was provided. Westinghouse /NRC status and understanding of issue are consistent.

4 IN-VESSEI, RETENTION.

The NRC (Monninger) indicated that the staff views the AP600 features to retain the core debris in-vessel as an enhancement over other plant designs. The main uncertainty that is affecting completion of the review is related to the response of the reactor vessel insulation during cavity flood-up and its effects on cooling of

.the reactor vessel. Bill Russell questioned the real need for vessel insulation. Westinghouse (Jim Scobel) noted that the insulation is a canned reflective insulation that serves a dual function to reduce reactor vessel heat loss and protect surrounding concrete from normal heat loads.

Bill Russell asked if it was necessary to insulate the lower head area and asked what the overall effect would be (thermal losses) if the insulation were removed from the lower head.

The NRC (Barrett) referred to a Finnish design that provided a passive mechanism that removes the insulation in a severe accident.

The staff is concerned about accepting an insulation concept reflected only by functional requirements.

12. Action W:

Westinghouse to perform a system level review of reactor vessel insulation. Evaluate the impacts of providing insulation on the walls to protect the concrete solely and not to reduce the thermallosses from the vessel.

PASSIVE IIYDROGEN CONTROL The NRC provided a short presentation on the technical areas being reviewed with respect to the use of PARS in the AP60(L These include the number and location of PARS (including impact of recombiner discharge), adequacy of existing testing, and effect of poisons.

NRC staff still awaiting submittal of the SSAR revision reflecting the design change to use PARS. This submittal will address number and kication of recombiners and impact of recombiner discharge. The Westinghouse position is that the number of tests performed is adequate to cover necessary phenomena in DBA space. With respect to poisons, PAR use is limited to DBA events and the quantity of poisons available in DBA space is small. Westinghouse is proposing to use two PARS. 'Ihe capacity of one is factor of four greater than the generation rates. Westinghouse emphasized that there should not be a need for a numerical impact from catalytic poisons.

NRC (Jack Kudrick) stated that they didn't see any major hurdles. The NRC wants identification of the j

testing database and currently database is not on AP600 docket. Westinghouse indicated that they will

'j incorporate EPRI and vendor data on PARS by reference.

13. Action W: Revision 3 of the SSAR will include PARS. Data will be incorporated via reference to the EPRI and vendor data.

14. Action W: Westinghouse to contact EPRI / vendor and facilitate delivery of data to the staff.

The NRC (Jack Kudrick) discussed staff concern on power supplies for igniters but noted that the staff is looking at PRA results.

15. Action N: NRC to provide feedback to Westinghouse on power supplies to llydrogen Igniters following completion of review of applicable portions of PRA. <

DISCUSSION ON PRHR RELIABILITY Bill Russell asked questions on the reliability of passive residual heat removal heat exchanger given the change from 1 PRHR to 2 PRHRs. He asked if Westinghouse had looked at operating experience for this type of component and extrapolated the concerns. Westinghouse noted that they had looked at BWR components of this type but the materials and chemistry are very different.

Bill Russell stated that he is interested in the impacts of PRHR leakage and asked whether Westinghouse had looked at circumferential cracking, impact of tubing integrity and IST, Bill Russell also asked whether Westinghouse had looked at operating experience for similar components and the impact of failure. He noted that this will be an important issue with respect of reliability of the PRHR.

16. Action W: Westinghouse to investigate reliability effects of PRHR leakage DESIGN CONTROL DOCUMENT NRC (Jerry Wilson) provided a discussion on proposed ways to implement the DCD for the AP600. Jerry Wilson indicated that information not in the DCD will not be carried forward on the rulemaking and therefore will not have issue preclusion. His presentation stressed that current Westinghouse SSAR revision efforts, particularly to include PRA, SAMDA, need to be sensitive to DCD needs. Westinghouse agreed to review NRC guidance when it is received and determine the best path.

17. Action N: NRC to issue guidance on preparation of the Design Control Document.

DSER STATUS OVERVIEW A brief status was provided on the AP600 DSER open items. NRC (Ted Quay) re-iterated that nothing will be written off in a final form until all necessary documentation is provided in a final form. In most cases this is an SSAR revision.

18. Action W: Westinghouse to rethink the process for revising the SSAR. Possible workaround is to issue chapter revisions (some subset of entire SSAR) i 1