ML13331A446
| ML13331A446 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/18/1990 |
| From: | Nandy F Southern California Edison Co |
| To: | NRC/IRM |
| References | |
| IEB-89-002, IEB-89-2, NUDOCS 9006200500 | |
| Download: ML13331A446 (2) | |
Text
Southern Californla Edison Company 23 PARKER STREET IRVINE, CALIFORNIA 92718 F.
R. NANDY TELEPHONE MANAGER OF NUCLEAR LICENSING June 18, 1990 (714) 587-5400 U. S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 NRC Bulletin No. 89-02 San Onofre Nuclear Generating Station Unit 1 Our response to your letter dated March 12, 1990, requesting that we expand the scope of our review to include all safety related check valves that are the subject of NRC Bulletin 89-02 will require additional time. Your March 12, 1990, letter requested a response within 90 days, which would be
-approximately June 15, 1990. Due to the additional effort and the time required to perform an independent review, the response will be delayed until August 31, 1990.
By letter dated January 31, 1990, we submitted our response to Bulletin 89-02, "Stress Corrosion Cracking of High Hardness Type 410 Stainless Steel Internal Preloaded Bolting in Anchor-Darling Model S350W Swing Check Valves or Valves of Similar Design." This bulletin requests that we perform a review of our safety related check valves to determine if any check valves at San Onofre Unit 1 may be subject to failures caused by stress corrosion cracking similar to those cited in the bulletin. We performed a review of our safety related check valves and found that we do not have any check valves subject to the requirements of the Bulletin. Our review, however, was limited in scope to the safety related check valves included in the In-Service Testing (IST) program.
By letter dated March 12, 1990, you requested that we expand the scope of our review to cover all safety related check valves including those not in the IST program. In order to assure that we include in our review all of the safety related check valves that are not in the IST program, we have performed a detailed review of our plant design documents. Preliminary results of this review indicate that none of the safety related check valves used in San Onofre Unit 1 are Anchor-Darling Model S350W. We are continuing our research of our design documents to determine if any safety related swing check valves use internal preloaded type 410 stainless steel bolting.
9006200500 900618::
PIR ADOCK 05000206 Q
Document Control Desk June 18, 1990 Our review to date indicates the swing check valves at San Onofre Unit 1 do not use type 410 stainless steel bolting. We are still in the process of verifying the type of bolting used for five swing check valves. If we identify any check valves which would require disassembly and inspection per the bulletin, we will perform the inspections during the Cycle 11 refueling outage. If our January 31, 1990, submittal had identified any valves requiring inspection, the Bulletin would have required the inspections to be performed during the Cycle 11 outage. For this reason, a short delay in our submittal of the results of our additional review will not have an impact on our overall schedule to comply with Bulletin 89-02.
Additionally, to ensure that our response to Bulletin 89-02 is complete, we are performing an independent verification of our results. These factors will require a delay in the submittal until August 31, 1990.
Please call me if you have any questions about this matter.
Very truly your cc: J. B. Martin, Regional Administrator, NRC Region V C. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3