ML052130299

Response Letter to David Weissman of Alliance for Nuclear Responsibility Diablo Canyon and San Onofre

ML052130299
Person / Time
Site:	Diablo Canyon, San Onofre
Issue date:	08/01/2005
From:	William Jones NRC/RGN-IV/DRP
To:	Weissman D Alliance for Nuclear Responsibility
References
Download: ML052130299 (3)

Text

August 1, 2005 David Weissman Alliance for Nuclear Responsibility P.O. Box 1328 San Luis Obispo, CA 93406-1328

Dear Mr. Weissman:

This letter is in response to your June 17, 2005, E-mail to our Public Affairs Officer, Victor Dricks, inquiring about the availability of comparative data on steam generator (SG) degradation rates for the San Onofre Nuclear Generating Station and the Diablo Canyon Nuclear Power Plant.

NRC cannot provide charts or diagrams or the kind of information that specifically addresses your questions regarding those facilities. As a safety regulator, the NRC closely monitors SG tube degradation mechanisms, rather than rates.

As part of its licensing requirements, the NRC established a SG surveillance program and reporting requirements that all nuclear plants must meet as a condition of operation. These requirements are identified in the Technical Specifications (license), "Steam Generator (SG)

Tube Surveillance Program," Sections 5.5.2.11 and 5.5.9, respectively. They establish the type of inspections, frequency, acceptance criteria, and repair and/or plugging limits. Licensees are directed to inspect tubes based on operating experience from similar plants, all nonplugged tubes with detectable wall penetrations greater than 20 percent, and tubes in those areas where prior experience has indicated potential problems may occur. Both Diablo Canyon and San Onofre are required by their Technical Specifications to report the number of tubes plugged after each SG tube inspection. During each refueling cycle, following SG tube inspection, licensees must verify their ability to meet NRC requirements through the next operating cycle (usually 18 to 24 months) prior to restart.

When we review these reports, we focus on whether the individual tubes are capable of performing their intended safety function. If too many tubes were plugged/repaired, the licensee would need to demonstrate that continued operation with the SGs is acceptable. We do not chart the data, which reflects degradation trends, but the information needed to do so is publicly available on the NRC website, where results of its SG tube inspections are posted:

http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/steam-gen.html.

David Weissman These are the ADAMS ML numbers for the most recent "annual" reports submitted by San Onofre and Diablo Canyon regarding the results of their SG tube inspections.

- San Onofre 2 - ML040850599

- San Onofre 3 - ML043020275

- Diablo Canyon 1 - ML050940293

- Diablo Canyon 2 - ML050820052 Help in using ADAMS is available by contacting the NRC Public Document Room staff at 1-800-397-4209.

Sincerely,

/RA/

William B. Jones Chief, Project Branch B Division Reactor Projects

David Weissman Electronic distribution to:

W. Jones (WBJ)

V. Dricks (VLD)

SISP Review Completed: __wbj__ ADAMS: : Yes G No Initials: __wbj__

Publicly Available G Non-Publicly Available G Sensitive  : Non-Sensitive S:\DRP\DRPDIR\Weissman-Alliance response letter.wpd RIV:PAO C:DRP/B VLDricks;df WBJones

/RA/ /RA/

8/1/05 8/1/05 OFFICIAL RECORD COPY T=Telephone E=E-mail F=Fax