ML16343A472
| ML16343A472 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 01/31/1997 |
| From: | Steven Bloom NRC (Affiliation Not Assigned) |
| To: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 9702050393 | |
| Download: ML16343A472 (6) | |
Text
January 31, 1997 Hr. Gregory H. Rueger Pacific Gas and Electric Company NPG Hail Code AlOD P. 0.
Box 770000 San Francisco, California 94177
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION'- THE LANDSLIDE POTENTIAL AT DIABLO CANYON POWER PLANT
Dear Hr. Rueger:
On January 3,
1997, Pacifi'c Gas and Electric Compan'y (PGtmE) declared an Unusual Event at the Diablo~Canyon Power Pla'nt due to a mud,slide on the county road leading to the plant. entrance.
This led to some concern on the part of the NRC staff as to the potential for land slides that could effect Plant Category I structures or equipment.
Our request for additional information is enclosed.
Please submit. your response within 60 days of receipt of this letter.
Sincerely, Original Signed By Docket Nos.
50-275 and 50-323
Enclosure:
Request for Additional Information cc w/encl:
See next page Steven D. Bloom, Project Manager Project Directorate IV-2 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation DISTRIBUTION:
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Mr. Gregory M. Rueger January 31, 1997 cc w/encl:
NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.
Box 369 Avila Beach, California 93424 Dr. Richard Ferguson, Energy Chair Sierra Club California 1100 11th Street, Suite 311 Sacramento, California 95814 Ms. Nancy Culver San Luis Obispo Mothers for Peace P. 0.
Box 164 Pismo Beach, California 93448 Chairman San Luis Obispo County Board of Supervisors Room 370 County Government Center San Luis Obispo, California 93408 Mr. Truman Burns Mr. Robert Kinosian California Public Utilities Commission 505 Van Ness, Room 4102 San Francisco, California 94102 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Harris Tower E Pavillion 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 Christopher J.
- Warner, Esq.
Pacific Gas 8 Electric Company Post Office Box 7442 San Francisco, California 94120 Mr. Robert P.
Powers Vice President and Plant Manager Diablo Canyon Nuclear Power Plant P. 0.
Box 56 Avila Beach, California 93424 Telegram-Tribune ATTN:
Managing Editor 1321 Johnson Avenue P.O.
Box 112 San Luis Obispo, California 93406 Mr. Steve Hsu Radiologic Health Branch State Department of Health Services Post Office Box 942732 Sacramento, California 94232 Diablo Canyon Independent Safety Committee ATTN:
Robert R. Wellington, Esq.
Legal Counsel 857 Cass Street, Suite D
Monterey, California 93940
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ENCLOSURE RE UEST FOR ADDITIONAL INFORMATION PACIFIC GAS AND ELECTRIC COMPANY DIABLO CANYON POWER PLANT UNITS NOS.
1 AND 2 DOCKET NOS.
50-275 AND 50-323 On January 3,
1997, Pacific Gas Electric Company (PG8E) declared an Unusual Event at the Diablo Canyon Power Plant due to a
mud slide on the county road leading to the plant entrance.
This led to some concern on the part of the NRC staff as to the potential for land slides that could effect Plant Category I structures or equipment.
Of particular concern are the effects of earthquake vibratory ground motion on soil slope stability following a period of prolonged precipitation.
A review of the Diablo Canyon Updated Final Safety Analysis Report (UFSAR) and the NRC Operating License Safety Evaluation Report indicates that the stability of cut slopes adjacent to the plant were analyzed and reviewed as part of the licensing process, but there is no discussion of the stability of natural slopes in either document.
Plant site geologic
- maps, Figure 2.5-8 and Figure 2.5-9, in the UFSAR show numerous areas marked as landslide deposits.
In addition, an aerial photograph which was taken during the construction of the plant appears to show a large landslide scar, on the hillside east of the plant buildings and south of the raw water storage reservoirs, with transmission line towers mounted on it.
Provide an analysis of the landslide hazard in the site vicinity and any potential impact on Category I structures and equipment and other important facilities, such as access roads.
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