ML20070L250

Forwards LERs 82-142/01T-0 & 82-001/01T-0.Detailed Event Analysis Submitted

ML20070L250
Person / Time
Site:	San Onofre
Issue date:	12/13/1982
From:	Ray H SOUTHERN CALIFORNIA EDISON CO.
To:	Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20070L253	List: ML20070L250
References
NUDOCS 8301030058
Download: ML20070L250 (2)

Text

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Southern California Edison Company S AN ONOFRE NLCLE AR GENER ATING STA TION 5%

P.O. B Ox 128 S A N C LEMENT E. C A LIFORNI A 92671 H. B. R AY tetspwome

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h U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement

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1450 Maria Lane, Suite 210 -; g Walnut Creek, California 94596-5368 W g&

Attention: Mr. R. H. Engelken, Regional Administrator

Subject:

Docket Nos. 50-361 and 50-362 14-Day Follow-Up Report Licensee Event Report No.82-142 (Docket No. 50-361)

Licensee Event Report No.82-001 (Docket No. 50-362)

San Onofre Nuclear Generating Station, Units 2 and 3

Reference:

Letter, H.B. Ray (SCE) to R.H. Engelken (NRC),

dated November 30, 1982 The referenced letter provided you with confirmation of our prompt notification of your office of a reportable occurrence involving Limiting Condition for Operations (LC0's) 3.7.5 and 3.0.3 on the Control Room Emergency Air Cleanup System (CREACUS).

Pursuant to sections 6.9.1.12b of Appendix A, Technical Specifications to Operating Licenses NPF-10 and NPF-15, for San Onofre Units 2 and 3, respectively, this letter provides the required follow-up report and completed Licensee Event Reports (LER's) for this occurrence.

On November 24, 1982, while Unit 2 was in Mode 3 and Unit 3 was in Mode 6, CREACUS Train A was placed in an inoperable status to allow charcoal filter replacement on cooling unit E-418. The Action Statement associated with LC0 3.7.5 allows operations to continue for seven days before requiring that the train be restored operable.

On November 28,1982 at 1230 while Unit 2 was in Mode 3, and Unit 3 was in Mode 6, Emergency Chiller E-335 was declared inoperable due to a motor winding high temperature trip. This rendered CREACUS Train B inoperable thus exceeding the limits of LC0 3.7.5. Technical Specification LC0 3.0.3 becaec governing for both units, allowing one hour before a Unit 2 shutdown /cooldown was required.

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8301030058 821213 3O PDR ADOCK 05000361 02 ? l

R. H. Engelken. December 13,1982 Unit 2 plant cooldown toward Mode 4 was initiated at 1300 and was terminated at 1700 on November 28, 1982, when E-335 was returned to operable status. Mode 4 was not achieved but LCO 3.0.3 was satisfied, which required action within one hour to place the plant in Mode 4 within the following six hours. No inimediate action was necessary at Unit 3 under LC0 3.7.5 (or Section 3.0.3). The unit was in Mode 6.

This event was caused by the failure of a Resistance Temperature Detector (RTD), in the motor winding high temperature trip circuit.

A. resistor was installed parallel with the RTD. This temporary modification allowed clearing of the trip and restoration of cooling unit E-335 to operable status. This did not eliminate motor protection since an additional existing RTD in the motor winding end turn slot is operating and is providing adequate protection for the motor.

An additional corrective measure will include a design change to use the installed spare RTD for the motor winding high temperature trip function.

It should be noted that failure of RTD's is not unexpected during the plant life and, therefore, no additional corrective measures are planned.

No event requiring CREACUS operation occurred during the time both trains were inoperable and hence, public health and safety were not affected.

If there are any questions regarding the above, please contact me.

Sincerely, bh ['NN7 k

Enclosures:

LER 82-142 (Unit 2)

LER 82-001 (Unit 3) cc: A. E. Chaffee (Resident Inspector, San Onofre Units 2 and 3)

U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Office of Management Information and Program Control Institute of Nuclear Power Operations

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