HBL-12-004, 10 CFR 50.59 Report of Changes, Tests, and Experiments for the Reporting Interval of January 1, 2010, Through December 31, 2011

10 CFR 50.59 Report of Changes, Tests, and Experiments for the Reporting Interval of January 1, 2010, Through December 31, 2011

ML12060A029
Person / Time
Site:	Humboldt Bay
Issue date:	02/21/2012
From:	Conway J Pacific Gas & Electric Co
To:	Document Control Desk, NRC/FSME
References
HBL-12-004
Download: ML12060A029 (3)

Text

ePacific Gas and John Conway 77 Beale Street, B32 Electric Company' Senior Vice President San Francisco, CA 94105 Energy Supply and Chief Nuclear Officer 415.973.3336 Fax: 415.973.2313 Internet: jtch@pge.com February 21, 2012 PG&E Letter HBL-12-004 10 CFR 50.59 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Docket No. 50-133, OL-DPR-7 Humboldt Bay Power Plant, Unit 3 10 CFR 50.59 Report of Chanqes, Tests, and Experiments for the Reportingq Interval of January 1, 2010, through December 31, 2011

Dear Commissioners and Staff:

Pursuant to 10 CFR 50.59, the enclosure to this letter contains the Report of Changes, Tests, and Experiments for Humboldt Bay Power Plant (HBPP) Unit 3 for the reporting interval of January 1, 2010 through December 31, 2011. The report provides a summary of a 10 CFR 50.59 evaluation for one change made to the facility as described in the Defueled Safety Analysis Report (DSAR). The report also provides a summary of a revision to a previously submitted change.

The changes summarized in the enclosed report were reviewed and accepted by the Plant Staff Review Committee (PSRC). The PSRC determined that the changes did not require NRC approval and.did not require changes to the HBPP Technical Specifications.

No tests or experiments not described in the DSAR were performed during the reporting period.

There are no regulatory commitments in this letter.

If you have any questions or require additional information, please contact Mr. David Sokolsky at (415) 973-5024.

Sincerely, nTCoway Senior Vice President- Energy upply and Chief Nuclear Officer cc/enc: Elmo E. Collins, Jr., Regional Administrator, NRC Region IV Robert J. Evans, NRC Region IV Inspector John B. Hickman, NRC Project Manager.

HBPP Humboldt Distribution

Enclosure PG&E Letter HBL-12-004 10 CFR 50.59 REPORT OF CHANGES, TESTS, AND EXPERIMENTS JANUARY 1, 2010, THROUGH DECEMBER 31, 2011 HUMBOLDT BAY POWER PLANT, UNIT 3 DOCKET NO. 50-133 Change 2010-01 is described below. The change was made to Humboldt Bay Power Plant (HBPP) Unit 3 during the period from January 1, 2010 through December 31, 2011. A summary of the associated 10 CFR 50.59 evaluation is also included. The HBPP Plant Staff Review Committee reviewed a more complete record of this change and determined the change did not require NRC approval and did not require a change to the HBPP Technical Specifications.

Change 2009-01 was submitted in the 10 CFR 50.59 report contained in PG&E Letter HBL-10-006, dated March 4, 2010. In that report, PG&E stated that if the 10 CFR 50.59 evaluation were modified, PG&E will notify the NRC. The 10 CFR 50.59 evaluation for Change 09-01 was subsequently revised, and PG&E is notifying the NRC of the revision in this report.

Description of Change 2010-01 This change to the facility as described in the Defueled Safety Analysis Report (DSAR) addressed the impact to Unit 3 of the elimination of circulating water flow following the permanent shutdown of Units 1 and 2. The previously described design function of the Unit 1 and 2 circulating water flow was the dilution of Unit 3 liquid radwaste (LRW) effluent entering the discharge canal. This design function was replaced by the dilution effect on the discharge canal that occurs during the transition from lower to higher Humboldt Bay tides.

Justification and Summary of 10 CFR 50.59 Evaluation 2010-01 The HBPP Offsite Dose Calculation Manual (ODCM) states that the instantaneous concentration of radioactive material released beyond the site boundary shall be less than or equal to 10 times the concentrations specified in 10 CFR 20, Appendix B, Table 2, Column 2. This limitation provides reasonable assurance that the levels of radioactive materials released to Humboldt Bay will result in exposures within (1) the Section II.A design objectives of 10 CFR 50, Appendix I, to a member of the public, and (2) the limits of 10 CFR 20.1302 to the population.

PG&E calculations showed that the 10 CFR 20 regulatory limits on radioactive liquid effluent concentrations could be met through a dilution mechanism not previously credited in the DSAR. That mechanism is the change in discharge canal volume, conservatively minimized, and the resultant mixing, which occurs from low tide to high tide. Therefore, with Units 1 and 2 permanently shutdown and circulating water no longer available, the DSAR-described design function of circulating water flow has been replaced with discharge canal dilution from tidal effects.

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Enclosure PG&E Letter HBL-12-004 Summary of Revision to 10 CFR 50.59 Evaluation 09-01 The purpose of Revision 1 to 10 CFR 50.59 Evaluation 09-01 was to clearly document that the guidance of NEI 96-07, "Guidelines for 10 CFR 50.59 Implementation,"

Revision 1 was followed in reaching the determination that the proposed change to replace the DSAR-described spent fuel pool (SFP) rupture evaluation methodology was not a departure from an evaluation methodology, and that prior NRC approval was therefore not required to make this change. Revision 1 to 10 CFR 50.59 Evaluation 09-01 also states that the RESRAD-OFFSITE computer code is used extensively by both the industry and the NRC for decommissioning-related dose assessments, and that NEI 96-07, Revision 1, states that a licensee may adopt a completely new methodology without prior NRC approval provided the methodology is approved by the NRC for its intended application.

A complete description of Change 09-01, and justification and summary of the 10 CFR 50.59 evaluation for Change 09-01 are included in PG&E Letter HBL-10-006, dated March 4, 2010.

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