ML16343A601
| ML16343A601 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/06/1998 |
| From: | Steven Bloom NRC (Affiliation Not Assigned) |
| To: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| Shared Package | |
| ML16342E202 | List: |
| References | |
| TAC-M98283, TAC-M98284, NUDOCS 9808100047 | |
| Download: ML16343A601 (4) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 205554001 August 6, 1998 Mr. Gregory M. Rueger, Senior Vice President and General Manager Pacific Gas and Electric Company NPG - Mail Code A10D P. O. Box 770000 San Francisco, California 94177
SUBJECT:
REQUEST FOR ADDITIONALINFORMATIONREGARDING PROPOSED W*
STEAM GENERATOR TUBE ALTERNATEREPAIR CRITERIA FOR DIABLO CANYON POWER PLANT, UNITS 1 AND 2 (TAC NOS. M98283 AND M98284)
Dear Mr. Rueger:
The NRC is currently reviewing a proposal to amend the technical specifications (TS) for Diablo Canyon, Units 1 and 2 to permit the application of alternate repair criteria for degraded steam generator tubing. The W* ("W-Star") repair criteria would permit steam generator tubes with
'laws located below the tubesheet secondary face to remain in service provided certain conditions are satisfied.
In order to complete our review of the your proposed TS amendment, the NRC staff requires additional information as described in the enclosure.
Questions 2 and 4 contain information that is considered to be proprietary by your vendor.
It is noted that satisfactory resolution of Question 1 is of critical importance to determining the acceptability of the proposed license amendment.
In addition, the NRC believes that you and your vendor may be unable to supply the data requested in Question 1 to support your response.
Ifthis is the case, then you may consider adopting additional requirements as part of the implementation of W*to verify, on a periodic basis, the conservatism in the proposed leak rate model developed in WCAP-14797, Revision 1, "Generic W" Tube Plugging Criteria for 51 Series Steam Generator Tubesheet Region WEXTEX Expansions."
Such requirements could include, additional testing of simulated steam generator tube flaws to benchmark the leak rate model, supplemental in-situ pressure testing of flaws in WEXTEXexpansions, or completion of leak rate testing on flawed tubes removed from actual steam generators.
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Mr. Gregory M. Rueger August 6, 1998 Please provide your response within 60 days from receipt of this letter. Ifyou have any questions regarding this matter, please contact me at (301) 415-1313.
Sincerely, Original Signed By Steven D. Bloom, Project Manager Project Directorate IV-2 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket Nos. 50-275 and 50-323
Enclosure:
Request for Additional Information cc w/encl (Questions 1,3, 5 through 7): See'next page
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