ML102010261

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Summary of July 13, 2010, Meeting with DNC to Discuss Generic Letter 2004-02 Supplemental Response Request for Additional Information
ML102010261
Person / Time
Site: Millstone Dominion icon.png
Issue date: 07/29/2010
From: Sanders C
Plant Licensing Branch 1
To:
Dominion Nuclear Connecticut
Sandeers, Carleen, NRR/DORL, 415-1603
Shared Package
ML102010281 List:
References
GL-04-002, TAC MC4695, FOIA/PA-2011-0115
Download: ML102010261 (5)


Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 29, 2010 LICENSEE: Dominion Nuclear Connecticut, Inc. (DNC)

FACILITY: Millstone Power Station, Unit NO.3

SUBJECT:

SUMMARY

OF JULY 13, 2010, MEETING WITH DNC TO DISCUSS GENERIC LETTER 2004-02 SUPPLEMENTAL RESPONSE REQUEST FOR ADDITIONAL INFORMATION (TAC NO. MC4695)

On July 13, 2010, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Dominion Nuclear Connecticut, Inc. (DNC).

Representatives from Atomic Energy of Canada Limited (AECL), DNC's contractor, participated via the phone. The purpose of the meeting was to discuss remaining issues identified during NRC staff review of the Millstone Power Station, Unit NO.3 (MPS3) Generic Letter (GL) 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors," supplemental response. Specifically, the meeting focused on the NRC's request for additional information (RAI) regarding the head loss and vortexing response. The meeting was a follow-up to the April 8, April 20, and June 7,2010, Category 1 public teleconferences on Millstone Power Station, Unit Nos. 2 & 3 GL 2004-02 supplemental response. A summary of the April 8, 2010, meeting can be found at Agencywide Documents Access and Management System (ADAMS) Accession No. ML101170575. A summary of the April 20, 2010, meeting can be found at ADAMS Accession No. ML101250623.

A summary of the June 7, 2010, meeting can be found at ADAMS Accession No. ML101590648.

The meeting was intended to give DNC the opportunity to explain its proposed approach for responding to the NRC staff's RAI dated February 4, 2010 (ADAMS Accession No. ML100070068), specifically MPS3's RAI NO.6. The meeting was also intended to give the NRC staff the opportunity to provide feedback regarding the licensee's proposed approach and to provide a mechanism for the NRC and DNC to come to mutual agreement on the remaining steps toward resolution of the outstanding GL 2004-02 issues for MPS3.

The licensee provided draft responses to the NRC staffs RAI dated April 8, 2010 (ADAMS Accession No. ML100980415). The licensee provided a revised copy of the draft responses based on discussions from the April 8, and April 20, 2010, teleconferences (ADAMS Accession No. ML101530556).

The slides from DNC's presentation can be found at ADAMS Accession No. ML101950505. For reasons provided in the slides, DNC's position is that the Rig 89 test is conservative.

The NRC staff believes the Rig 89 test is non-conservative with respect to the debris bed formation process. This is because of the tendency of debris to temporarily settle in front of the strainer, which has not been demonstrated to be representative of the plant, the debris addition

-2 rate, which may have been too great, and because the small (Rig 89) rig tends to result in flow streams not representative of the plant with respect to allocating debris uniformly over the strainer.

The NRC staff agreed that there is no visual evidence of debris bed non-uniformity, but that many of the NRC staff's concerns about the small test rig (Rig 89) are well documented; for example, the concern documented in the North Anna audit report (ADAMS Accession No.

Ml09041 0626).

The NRC staff stated that they agree that the Rig 89 submergence is more representative of the plant than the Rig 33 submergence, but the NRC staff views the submergence effect as having a minimal impact based on plant-specific deaeration calculations.

ONC stated that the use of river water for the Rig 33 test could have impacted its results, but the NRC staff and ONC agreed that this impact is probably not significant.

ONC stated that the large margins and various conservatisms provide confidence that overall strainer performance is adequate. The NRC staff stated that the licensee should address the conservatisms comprehensively in the final RAI response.

ONC stated that, contrary to the NRC staff's understanding from the June 7, 2010, teleconference, ONC is not adding the Rig 89 chemical effects head loss to the Rig 33 non chemical head loss.

On July 28, 2010, there will be a follow-up public teleconference (ADAMS Accession No.

rvll1 01950284), at which time the NRC staff will provide feedback on potential paths to resolve the remaining head loss and vortexing concern without reliance upon a holistic conclusion by the Integration Review Team (IRT). ONC is also considering options for resolution, including holistic resolution via the IRT process, and will provide that information during the meeting.

-3 No proprietary information was discussed at the meeting. No members of the public were in attendance. A list of attendees is provided in the enclosure.

If you have any questions, please contact me at 301-415-1603.

tJ Carleen J. san¢.e.r Project Manager I

Plant l.icensinqB nch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-423

Enclosure:

As stated cc w/encls: Distribution via Listserv

LIST OF ATTENDEES JULY 13 2010, MEETING WITH DOMINION NUCLEAR CONNECTICUT, INC. (DNC)

MILLSTONE POWER STATION, UNIT NO.3 GENERIC LETTER 2004-02 SUPPLEMENTAL RESPONSE W. Bartron J. Dakers M. Legg C. Maxson J. Rigatti R. Tooker W. Craft D. Rhodes D. Guzonas J. Lehning C. Sanders M. Scott Enclosure

- 3 No proprietary information was discussed at the meeting. No members of the public were in attendance. A list of attendees is provided in the enclosure.

If you have any questions, please contact me at 301-415-1603.

Carleen J. Sanders, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-423

Enclosure:

As stated cc w/encls: Distribution via Listserv DISTRIBUTION:

PUBLIC Branch Reading MScott, NRR PKlein, CSteger, NRR JLehning, NRR NRR RidsAcrsAcnw_MailCTR Resource RidsNrrDorlLpll-2 Resource RidsOgcRp Resource RidsNrrPMMilistone Resource RidsNrrLAABaxter Resource RidsRgnlMailCenter Resource ADAMS Accession Nos.: Package/ML102010281; Mtg Notice: ML101800513; Mtg Handout: ML101950505 MtQ Sumrnarv: ML102010261 OFFICE DORULPL1-2/PM DORULPL1-2/LA NRRISSIB/BC DORULPL1-2/BC NAME CSanders ABaxter MScott HChernoff DATE 7/29/10 7/26/10 7/22/10 7/29/10 Official Record Copy