ML100130753

Summary of Meeting with Representatives of Pacific Gas and Electric Company to Discuss Preliminary Seismic Studies Diablo Canyon Power Plant, Units 1 and 2 Shoreline Fault

ML100130753
Person / Time
Site:	Diablo Canyon
Issue date:	01/20/2010
From:	Wang A Plant Licensing Branch IV
To:	Pacific Gas & Electric Co
Wang, A B, NRR/DORL/LPLIV, 415-1445
References
Download: ML100130753 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 January 20, 2010 LICENSEE: Pacific Gas and Electric Company FACILITY: Diablo Canyon Power Plant, Units 1 and 2

SUMMARY

OF JANUARY 5, 2010, MEETING WITH PACIFIC GAS AND ELECTRIC COMPANY REGARDING SHORELINE FAULT On January 5, 2010, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) staff and representatives of the Pacific Gas and Electric Company (PG&E, the licensee) at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. PG&E provided a status of the efforts to estimate and constrain the newly identified Shoreline fault at the Diablo Canyon Power Plant (DCPP) site. The licensee provided the NRC staff presentation slides in support of this meeting (Agencywide Documents Access and Management System (ADAMS) Accession No. IVIL100060063). A list of attendees is enclosed.

The areas discussed during the meeting included the following:

• Location of the fault,

• Variations in the seismicity alignment,

• Geophysical profiling,

• Mapping offshore wave-cut platforms,

• Style of faulting,

• Constraints on activity (fault slip-rate),

• Length and rupture area,

• Magnitude of potential earthquakes,

• Ground motions, and

• Primary surface fault rupture; secondary fault deformation.

The Shoreline fault study has determined the following:

1. The microseismicity lineament is a real feature,

2. The Shoreline fault zone has 3 segments,

3. The Shoreline fault is a vertical, strike-slip fault which is consistent with the earlier assumptions, and

4. The Shoreline fault is 300 meters from the intake structure and 600 meters from the power block as compared to the 1,000 meters previously assumed.

- 2 Based on the above, the operability determination performed by the licensee in November 2008 which determined the Hosgri fault was bounding is still valid. In addition, because of the closeness of the power block to the Shoreline fault, PG&E performed additional analysis to determine if secondary fault deformation could damage any safety-related systems or structures. This study concluded that any damage due to secondary faulting is very unlikely and the impact on the DCPP seismic core damage frequency is negligible.

PG&E stated that the Shoreline fault studies were accelerated and the current schedule is to have the Shoreline fault study completed by the end of 2010. The rest of the tectonic modeling for the central California region is due to be complete in 2012. Barbara Bryon from the California Energy Commission (CEC) asked if three-dimensional imaging studies as recommended by the CEC are going to be performed. PG&E stated it is looking into the funding for this project and, if funded, would extend the central California study until 2013.

PG&E agreed to provide the following for the NRC staff:

1. Any additional onsite geotechnical site characteristics corrected using data gathered for the independent spent fuel storage facility,

2. A copy of a paper by Lloyd Cluff dated 1985 regarding techniques for assessment of fault activity slip rates, and

3. Technical write-up of the assessments of impact by secondary faulting due to be completed in February 2010.

The NRC staff stated another meeting would be useful before PG&E completes the Shoreline fault study at the end of the year and PG&E agreed. Members of the public were in attendance.

Public Meeting Feedback forms were not received.

Please direct any inquiries to me at 301-415-1445, or Alan.Wang@nrc.gov.

~vJ Alan Wang, ~anager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323

Enclosure:

List of Attendees cc w/encl: Distribution via Listserv

LIST OF ATTENDEES JANUARY 5, 2010, MEETING U.S. NUCLEAR REGULATORY COMMISSION (NRC) WITH PACIFIC GAS AND ELECTRIC COMPANY (PG&E)

DIABLO CANYON SHORELINE FAULT NAME AFFILIATION L. Cluff PG&E N. Abrahamson PG&E T. Baldwin PG&E T. Grebel PG&E M. Markley NRC K. Manoly NRC A. Kammerer NRC A. Wang NRC R. Karas NRC V. Graizer NRC A. Stieve NRC G. Bagchi NRC S. Devlin NRC G. Stirewalt NRC N. Chokshi NRC R. Pichumani NRC Y.U NRC L. Bauer NRC K. Green NRC P-Y. Chen NRC C. Denissen NRC J. Braisted NRC B. Bryon California Energy Commission R. MacDonald California Energy Commission D. Weisman Alliance for Nuclear Responsibility Enclosure

-2 Based on the above, the operability determination performed by the licensee in November 2008 which determined the Hosgri fault was bounding is still valid. In addition, because of the closeness of the power block to the Shoreline fault, PG&E performed additional analysis to determine if secondary fault deformation could damage any safety-related systems or structures. This study concluded that any damage due to secondary faulting is very unlikely and the impact on the DCPP seismic core damage frequency is negligible.

PG&E stated that the Shoreline fault studies were accelerated and the current schedule is to have the Shoreline fault study completed by the end of 2010. The rest of the tectonic modeling for the central California region is due to be complete in 2012. Barbara Bryon from the California Energy Commission (CEC) asked if three-dimensional imaging studies as recommended by the CEC are going to be performed. PG&E stated it is looking into the funding for this project and, if funded, would extend the central California study until 2013.

PG&E agreed to provide the following for the NRC staff:

4. Any additional onsite geotechnical site characteristics corrected using data gathered for the independent spent fuel storage facility,

5. A copy of a paper by Lloyd Cluff dated 1985 regarding techniques for assessment of fault activity slip rates, and

6. Technical write-up of the assessments of impact by secondary faulting due to be completed in February 2010.

The NRC staff stated another meeting would be useful before PG&E completes the Shoreline fault study at the end of the year and PG&E agreed. Members of the public were in attendance.

Public Meeting Feedback forms were not received.

Please direct any inquiries to me at 301-415-1445, or Alan.Wang@nrc.gov.

/RN Alan Wang, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323

Enclosure:

List of Attendees cc w/encl: Distribution via Listserv DISTRIBUTION:

PUBLIC RidsNrrDe Resource RidsOgcRp Resource LPL4 Rlf RidsNrrDeEeeb Resource RidsRgn4MailCenter Resource RidsAcrsAcnw_MailCTR Resource RidsNrrDeEmcb Resource CDenissen, RIVIDRS/EB1 RidsNroDeEmb2 Resource RidsNrrDlrRpb2 Resource JBraisted, RIVIDRP/RPB-C RidsNroDser Resource RidsNrrDorlLpl4 Resource WMaier, RIV RidsNroDserRgs1 Resource RidsNrrPMDiabloCanyon Resource LTrocine, EDO Region IV RidsNroDserRgs2 Resource RidsNrrLAJBurkhardt Resource ADAMS Accession Nos. Meeting Notice ML1093560100, Meeting Summary ML100130753, Handouts ML100060063 OFFICE NRRlLPL4/PM NRRlLPL4/LA NRR/LPL4/BC NRR/LPL4/PM NAME AWang JBurkhardt MMarkley AWang DATE 1/20/10 1/19/10 1/20/10 1/20/10 OFFICIAL RECORD COpy