ML20041C684
| ML20041C684 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/16/1982 |
| From: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| REF-SSINS-6820 IEB-81-03, IEB-81-3, NUDOCS 8203020459 | |
| Download: ML20041C684 (2) | |
Text
Bulletin Reply 81-Q3 7,
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RECEfV90 U.S. Nuclear Regulatory Commission 79 Office of Inspection and Enforcement g7 MAR 011982>
Region V a muss sunserammes 1450 Maria Lane, Suite 210 3'esammena p
Walnut Creek, CA 94596-5368 1
Attention:
R.H. Engelken, Director FG DOCKET NO. 50-206 SAN ON0FRE UNIT 1
Dear Mr. Engelken:
Subject:
IE Bulletin 81-03 Referenccs:
1.
IE Bulletin 81-03, Flow Blockage of Cooling Water to Safety System Components by Corbicula Sp. ( Asiatic Clam) and Mytilus Sp. (Mussel).
2.
Letter, J.G. Haynes (SCE) to R.H. Engelken (NRC),
dated June 4,1981. Response to IE Bulletin 81-03.
3.
Letter, J.G. Haynes (SCE) to R.H. Engelken (NRC),
dated June 9,1981.
Licensee Event Report 81-009 attached.
Licensee Event Report 81-009 reported a blockage on the saltwater discharge side of Component Cooling Heat Exchanger E-20A due to the growth of a salt water arthropod identified as Pollicipes (Mitella) polymerus (gooseneck barnacle). Flow blockage of safety related systems by this specific organism was not referenced in the subject IE Bulletin (Reference 1) or discussed in the response (Reference 2). The submittal letter for LER 81-009 (Reference 3) concluded that the barnacle growth which developed during the 1980-81 plant outage would not recur once the plant returned to normal operation because of heat treatment of the Saltwater Cooling System at designated intervals.
To preclude the eventuality of a similar blockage during a future extended outage, the Unit 1 Preventive Maintenance Program has been revised. Every six months during an extended outage, the Component Cooling Heat Exchangers will be individually disassembled and the in-ternals and associated butterfly valves inspected for the presence of marine growth that could potentially lead to flow blockage.
Since the plant has endured outages in excess of six months in the past without gg f, 8203020459 820216 (E\\
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U.S. Nuclear Regulatory Commission February 16, 1982 evidence of this problem, the stated interval is considered sufficient.
However, Preventive Maintenance Sheet CCW-10, which governs the inspec-tion, has been footnoted to require a second inspection four months later, should the first inspection show undesirable marine growth.
Including the requirement in the PM Program will assure inspection at the specified interval (s). A procedure covering disassembly, inspec-tion and cleaning of these components is in the process of being issued.
Please contact me if you have any further questions on this matter.
b
/
cc:
U.S. Nuclear Regulatory Commission L.F. Miller - USNRC Resident Inspector
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