ML102220110

July 28, 2010, Summary of Teleconference with DNC to Discuss Generic Letter 2004-02 Supplemental Response Request for Additional Information

ML102220110
Person / Time
Site:	Millstone
Issue date:	09/14/2010
From:	Sanders C Plant Licensing Branch 1
To:
Sandeers, Carleen, NRR/DORL, 415-1603
References
GL-04-002, TAC MC4695, FOIA/PA-2011-0115
Download: ML102220110 (4)

Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555-0001 September 14, 2010 LICENSEE:

Dominion Nuclear Connecticut, Inc. (DNC)

FACILITY: Millstone Power Station, Unit NO.3

SUMMARY

OF JULY 28, 2010, TELECONFERENCE WITH DNC TO DISCUSS GENERIC LETTER 2004-02 SUPPLEMENTAL RESPONSE REQUEST FOR ADDITIONAL INFORMATION (TAC NO. MC4695) On July 28, 2010, a Category 1 public teleconference was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Dominion Nuclear Connecticut, Inc. (DNC). 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 and to the July 13, 2010, Category 1 public meeting on MPS3 GL 2004-02 supplemental response. A summary of the April 8, April 20, and June 7, 2010, teleconferences can be found at Agencywide Documents Access and Management System (ADAMS) Accession Nos. ML101170575, ML101250623, and ML101590648, respectively. A summary of the July 13, 2010, public meeting can be found at ADAMS Accession No. ML102010261. The handouts from the July 13, 2010, public meeting can be found at ADAMS Accession No. ML101950505. This meeting was intended to give DNC the opportunity to discuss potential paths forward for responding to the NRC staffs RAI dated February 4, 2010 (ADAMS Accession No. ML100070068), specifically MPS3's RAI NO.6. 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 NRC staff provided feedback on potential paths to resolve the remaining head loss and vortexing concern. The following potential approaches were discussed: Perform a chemical test in the Rig-89 using a more prototypical debris bed. Perform a chemical test in the Rig-33 at a pool depth representative of MPS3. Demonstrate the Rig-33 test is non-representative of MPS3 through further testing (e.g. run the Rig-89 test, lowering the water level to observe change in head loss, to demonstrate the impact of the water level on the test results). The NRC staff also provided feedback on a holistic evaluation the licensee might perform in the absence of further testing, stating DNC should consider the following:

-2The NRC staff also provided feedback on a holistic evaluation the licensee might perform in the absence of further testing, stating DNC should consider the following: Providing a discussion of the apparent discrepancy in the head loss effects of calcium addition between Rig 33 and Rig 89 tests as it relates to any conclusions about the effects of calcium phosphate precipitate. Providing estimated calcium concentration considering all plant-specific calcium sources (e.g., insulation materials, bare concrete, concrete dislodged from a loss-of-coolant accident jet) and the Atomic Energy of Canada Limited leaching test results. Providing results of the evaluation of the structural limit on the strainer. Use of the most limiting Rig-33 results in comparing head loss against margin. Providing a curve of limiting strainer design margins (e.g., net positive suction head, strainer differential pressure, flashing) versus time along with a discussion of the potential additional head loss caused by chemical precipitates. Providing justification for any assumptions related to delayed precipitation timing. Consulting licensees' successful holistic approaches.

DNC agreed to provide a potential path forward, including a submittal date for a draft holistic argument.

by August 4,2010. 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 contac me at 301-415-1603.

Carleen J. Sa e s, Project Manager Plant LicensinB anch 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 Mark Sartain William Bartron Martin Legg Joseph Rigatti Dave Dakers Dave Sommers Wanda Craft Gary Nayler Paul Klein John Lehning Carleen Sanders Michael Scott Steven Smith Matthew Yoder LIST OF JULY 282010, TELECONFERENCE DOMINION NUCLEAR CONNECTICUT, INC. MILLSTONE POWER STATION, UNIT GENERIC LETTER 2004-02 SUPPLEMENTAL Enclosure

-2The NRC staff also provided feedback on a holistic evaluation the licensee might perform in the absence of further testing, stating DNC should consider the following: Providing a discussion of the apparent discrepancy in the head loss effects of calcium addition between Rig 33 and Rig 89 tests as it relates to any conclusions about the effects of calcium phosphate precipitate. Providing estimated calcium concentration considering all plant-specific calcium sources (e.g., insulation materials, bare concrete, concrete dislodged from a loss-of-coolant accident jet) and the Atomic Energy of Canada Limited leaching test results. Providing results of the evaluation of the structural limit on the strainer. Use of the most limiting Rig-33 results in comparing head loss against margin. Providing a curve of limiting strainer design margins (e.g., net positive suction head, strainer differential pressure, flashing) versus time along with a discussion of the potential additional head loss caused by chemical precipitates. Providing justification for any assumptions related to delayed precipitation timing. Consulting licensees' successful holistic approaches. DNC agreed to provide a potential path forward, including a submittal date for a draft holistic argument, by August 4, 2010. 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.

/raj 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 RidsNrrPMMillstone Resource RidsNrrLAABaxter Resource RidsRgnlMailCenter Resource tq 0 Ice: ML101950284 Mt tq urnmarv: via e ADAMS Accession Nos.: Packace:

ML102220488, Mt N , S ML102220110

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DATE 09/07/10 09/01/10; 09/13/10 09/09/10 DORULPL 1-2/BC HChernoff 09/14/10 ..Official Record Copy