05000206/LER-1981-009, Forwards LER 81-009/01T-0.Detailed Event Analysis Also Submitted

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Forwards LER 81-009/01T-0.Detailed Event Analysis Also Submitted
ML20009A227
Person / Time
Site: San Onofre Southern California Edison icon.png
Issue date: 07/08/1981
From: Haynes J
SOUTHERN CALIFORNIA EDISON CO.
To: Engelken R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20009A228 List:
References
NUDOCS 8107090270
Download: ML20009A227 (2)
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LER-1981-009, Forwards LER 81-009/01T-0.Detailed Event Analysis Also Submitted
Event date:
Report date:
2061981009R00 - NRC Website
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J. G. H AY N E S T E L E P64 0 N E (213)S72-1742 M AN AGE R OF NUCLE AR OPER Af f 0NS 7/8/61 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement

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hMi l DOCKET No. 50-206 p-SAN ON0FRE - UNIT 1

Dear Sir:

Reference:

Letter dated June 9,1981 from SCE (J.M. Curran) to NRC (R. H. Engelken)

The referenced letter provided prompt written notification to your office of growth of some form of saltwater arthropod on the saltwater discharge pipe of the component cooling water heat exchanger E-20A such that the cross-sectional diameter was effectively reduced. This caused low coolant flod and mdlfunction of the butterfly valve. Further, the growth of the arthropod had partially blocked the heat exchanger tubing. Submittal is in accordance with the reporting requirements stipulated in Section 6.9.2 of Appendix A to our Provisional Operating License DPR-13.

In addition, a completed copy of Licensee Event Report No.81-009 is enclosed.

The saltwater arthropod was identified as Pollicipes (Mitella) polymerus commonly known as the gooseneck barnacle.

It is a common arthropod which has a high temperature tolerance, lives in the intertidal zone, likes turbulent water and is limited to caves and rocks with a water-air flow interface and dark environment.

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U. S. Nuclear Regulatory Commission Page # 2 An inspection revealed that the gooseneck barnacles were present from the heat exchanger discharge tube sheet outward toward the sea water discharge piping. The heat exchanger inlet tube sheet was found to be free of the barnacles. The partially plugged heat exchanger tubes were cleaned by shooting abrasive balls through the tubes using hign pressure air.

The heat exchanger tube sheet area and discharge piping were manually cleaned beyond the butterfly valve.

This incident occurred because of the current protracted shutdown of San Onofre Unit I which has lasted over 14 months. This extended shutdown has meant that the saltwater cooling system has not been heat treated for over a year. The plant is currently making preparation for return to power, at which point heat treatment can be renewed to control the barnacle growth in the manner which has been typical of San Onofre operations in the past.

In order to kill 100 percent of the organisms, any one of the following temperature-tine combinations would be necessary:

97'F for 3.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />,101'F for 1.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, or 105'F for 0.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

Pollicipes is expected to be less tolerant than the Bay Mussel (Mitilus), for which the heat treatment procedure of SONGS 1 was designed to control.

Therefore, conducting normal heat treatment at designated intervals will control Pollicipes. This is evidenced by the fact that the barnacle (Pollicipes) has not occurred in the past when SONGS 1 was in normal operation.

If you have any questions or desire additional information concerning this matter, please contact me.

Sincerel,

gh Attachments:

Licensee Event Report 81-009 cc:

L. F. Miller (NRC Resident Inspector)

Director, Office of Management Information & Program Control Director, Nuclear Safety Analysis Center

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