ML20079H331

Special Rept:On 911001,Train B Emergency Diesel Generator Declared Inoperable to Perform Quarterly Preventive Maint & to Verify Torque on Cam Shaft.Caused by Fractured/Cracked Cam Shaft.Fire Watch Established within 1 H

ML20079H331
Person / Time
Site:	San Onofre
Issue date:	10/08/1991
From:	Rosenblum R SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9110110029
Download: ML20079H331 (2)

Text

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Southem Califomia Edison Company 23 PARKER STREET IRVINE CALIFOFtNI A 9271B RM ROSE N DLUM TELEPHONE

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October 8, 1991 <7'4> s4-4 sos U. S. Nuclear Regulatory Commission )

Attention: Document Control Desk Washington, D. C. 20555 Gentlemen:

Subject:

Docket Nos. 50-361 and 50-362 Special Report San Onofre Nuclear Generating Station, Unit 2 and Unit 3 Technical Specification (TS) Section 3.7.8.2, action b, of facility Licenses NPF-10 & NPF-15 for San Onofre Nuclear Generating Station, Unit 2 and 3 respectively, requires Southern California Edison (SCE) to provide a Special Report when any of the safety related spray and/or sprinkler systems listed in Table 3.7-5 become inoperable for more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This letter provides the Special Report required by TS 3.7.8.2, action b.

The safety related spray and/or sprinkler systems will perform their intended functions when offsite power is available; however, in accordance with the Updated Fire Hazard Analysis (UFHA), the operability of these systems also requires the availability of emergency power. This required emergency power is supplied by the Unit 2 or Unit 3 train B Emergency Diesel Generator (EDG).

On October 1, 1991, at 04:50, with Unit 2 in Mode 6 and Unit 3 in Mode 1, the Unit 3 train B EDG G003 was declared inoperable to perform required quarterly preventative maintenance and to verify the torque on the cam shaft bearing block bolts. The Unit 2 train B EDG G003 was also inoperable. Therefore, the Unit 2 and 3 safety-related spray and/or sprinkler systems were rendered inoperable at the time Unit 3 EDG G003 was removed from service.

In accordance with Unit 2 and Unit 3 TS 3.7.8.2, action a, the necessary fire watch was established within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> after removing Unit 3 EDG G003 from service. The scheduled duration of the EDG outage was within the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> time limit of TS 3.7.8.2 action b. However, the inspection of Unit 3 EDG G003 revealed one fractured and three cracked camshaft to stubshaft dowel bolts which unexpectedly de?ayed reassembly of the EDG.

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' Document Control Desk October 8, 1991 The Unit 3 train B EDG was returned to service at 22:00 on October 3, 1991, af ter the necessary repairs, testing, and final inspection were satisfactorily completed. Therefore, the safety-related spray and sprinkler systems became operable end the Unit 2 and Unit 3 limiting conditions for operation of TS 3.7.8.2 were satisfied. The safety-related spray and sprinkler systems were inoperable for a total of 65 hours7.523148e-4 days <br />0.0181 hours <br />1.074735e-4 weeks <br />2.47325e-5 months <br />. ,

If you require any additional information regarding this Special Report.

please let me know.

Very truly yours, AtwAL~A$

cc: J. B. Martin, Regional Administrator, NRC Region V C. W. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1, 2, & 3 l

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