ML12284A072

Summary of Preapplication Meeting with Pacific Gas and Electric to Discuss License Amendment Request Related to New Reactor Coolant Loss of Flow Analysis at Diablo Canyon Power Plant, Units 1 and 2

ML12284A072
Person / Time
Site:	Diablo Canyon
Issue date:	10/16/2012
From:	Joseph Sebrosky Plant Licensing Branch IV
To:	Office of Nuclear Reactor Regulation
Sebrosky J NRR/DORL/LPLIV 301-415-1132
References
TAC ME9435, TAC ME9436
Download: ML12284A072 (4)

Text

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~"i October 16. 2012

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Pacific Gas and Electric Company FACILITY:

Diablo Canyon Power Plant, Unit Nos. 1 and 2

SUMMARY

OF SEPTEMBER 25,2012, PREAPPLICATION MEETING WITH PACIFIC GAS AND ELECTRIC COMPANY RELATED TO LICENSE AMENDMENT REQUEST FOR CHANGES IN THE LOSS OF COOLANT FLOW ANALYSIS (TAC NOS. ME9435 AND ME9436)

On September 25,2012, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of Pacific Gas and Electric Company (PG&E, the licensee) at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. PG&E requested this pre-application meeting to discuss its plans for a license amendment request (LAR) related to changes in the complete loss of forced reactor coolant flow analysis for Diablo Canyon Power Plant, Unit Nos. 1 and 2. The meeting notice and agenda, dated September 6, 2012, are available in the Agencywide Documents Access and Management (ADAMS) at Accession No. ML12248A115. The licensee's meeting slide presentation is available at ADAMS Accession No. ML12284A090. A list of attendees is provided in the Enclosure.

PG&E described the issue to be resolved in the proposed LAR, the options that it considered to resolve the issue, and the preferred option that it has chosen to resolve the issue. PG&E indicated that the issue to be resolved is that the current accident analysis for complete loss of forced reactor coolant flow credits the reactor trip system reactor trips on undervoltage (UV) and underfrequency (UF) on the reactor coolant pump 12 kiloVolt (kV) power supply buses as the primary trip to prevent exceeding the departure from nucleate boiling ratio (DNBR) limit.

However, the 12 kV bus UV and UF relays, potential transformers (PTs), and test switches are not Design Class I and are not seismically qualified. PG&E considered three different options that are described in its meeting slides and ultimately decided to pursue the option to credit the existing Design Class I reactor coolant system (RCS) low-flow trip as the primary method to prevent exceeding the DNBR limit during a complete loss of forced reactor coolant flow accident. The NRC staff offered the following items for PG&E to consider in developing its LAR:

Consider providing information in the LAR to ensure that the 90 percent Technical Specification setpoint for reactor coolant loop flow based on differential pressure is still valid for the loss of reactor coolant flow analysis. For example, the elbow taps locations for the measurement of the differential pressure are still appropriate.

Recognizing that the reactor coolant pump flow degrades over time, consider providing the reactor coolant loop flow values used in the loss of reactor coolant flow analysis and the basis for them. Consider providing information that would correlate the total reactor coolant flow to the loop flows.

- 2 Consider providing the DNBR analysis method used previously in the loss of reactor coolant flow analysis in the LAR and providing the NRC approval letter for this analysis method.

Consider providing the current analysis primary trip and the DNBR and the new analysis primary trip and the DNBR.

Consider identifying whether changes to the initial conditions were made for the new loss of reactor coolant flow analysis from the previous analysis.

PG&E indicated that it would consider the staff's insights and make adjustments to the LAR, as appropriate, to address them.

v.

roject Manager Docket Nos. 50-275 and 50-323

Enclosures:

Ust of Attendees cc w/encl: Distribution via Ustserv

LIST OF A TIENDEES SEPTEMBER 25,2012, MEETING WITH PACIFIC GAS AND ELECTRIC COMPANY REGARDING REVISED LOSS OF COOLANT FLOW ANALYSIS FOR DIABLO CANYON POWER PLANT, UNITS 1 AND 2 DOCKET NOS. 50-275 AND 50-323 NAME Kenneth Schrader Dan Brosnan*

Mark Sharp*

Brandy Lopez*

Jim Andrachek Prem Sahay*

Summer B. Sun Samir Darbali Jim Andersen Josh Miller Joe Sebrosky Leonard Willoughby*

Dean Overland*

• participated via telephone ORGANIZATION Pacific Gas and Electric Pacific Gas and Electric Pacific Gas and Electric Pacific Gas and Electric Westinghouse U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission (Region IV)

U.S. Nuclear Regulatory Commission (Region IV)

Enclosure

- 2 Consider providing the DNBR analysis method used previously in the loss of reactor coolant flow analysis in the LAR and providing the NRC approval letter for this analysis method.

Consider providing the current analysis primary trip and the DNBR and the new analysis primary trip and the DNBR.

Consider identifying whether changes to the initial conditions were made for the new loss of reactor coolant flow analysis from the previous analysis.

PG&E indicated that it would consider the staff's insights and make adjustments to the LAR, as appropriate, to address them.

Please direct any inquiries to me at 301-415-1132 or at Joseph. Sebrosky@nrc.gov.

IRA!

Joseph M. Sebrosky, Senior Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323

Enclosures:

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

PUBLIC SKennedy, EDO RIV LPLIV Reading VDricks, OPA RIV RidsAcrsAcnw_MailCTR Resource TWertz, NRR RidsNrrDeEeeb Resource WMaier. RIV RidsNrrDeEicb Resource JAndersen. NRR/DE/EEEB RidsNrrDorl Resource PSahay, NRRIDE/EEEB RidsNrrDorlLpl4 Resource SSun, NRR/DSS/SRXB RidsNrrDssSrxb Resource SDarbali, NRR/DE/EICB RidsNrrDssStsb Resource JMiller, NRR/DSS/SRXB RidsNrrLAJBurkhardt Resource LMicewski, RI, RIV RidsNrrPMDiabloCanyon Resource LWilioughby. RI, RIV RidsOgcRp Resource DOverland. RI, RIV RidsOpaMail Resource NO'Keefe, RIV/DPR/PRB-B RidsRgn4MailCenter Resource LMiller, RIV

. ee Ing ADAMS A ccesslon Nos. Meetmg N0l'Ice ML12248A115 MrSummary ML12284A072. I L

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• JSebrosky 1Q/16/12 10/15/12 DATE 10116/12 10/15/12 10/16/12 OFFICIAL RECORD COpy