ML20141M461
| ML20141M461 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 08/27/1992 |
| From: | Rosenblum R SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9208280331 | |
| Download: ML20141M461 (2) | |
Text
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x; Southem Califomia Edison Company 23 PARVER STREET j
IRVINE, C ALIFORNIA 92718 R. M ROSE NBLUM TrilPH m E 9
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mu 2E1 ="s August 27, 1992 U. S. Nuclear Regulatory Commission Attention: Document Control Desk 4
j Washington, D.C. 20555 i
Gentlemen:
1
Subject:
Docket No. 50-361 j
Special Report on Inoperable Noble Gas Monitor San Onofre Nuclear Generating Station Unit 2 i
Technical Specifications (TS) 3.3.3.1 table 3.3-6 Action 19, for San Onofre i
Nuclear Generating Station, Unit 2, requires Southern California Edison (SCE) to provide a Special Repart when the Condenser Evacuation System Noble Gas Monitor becomes inoperable for longer than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> during Modes 1, 2, 3, and i
l 4.
This letter provides the Special Report required by TS 3.3.3.1.
On August 10,1992, at 1806 with Unit 2 in Mode 1, Condenser Evacuation System Wide Range Noble Gas Monitor 2RT-7870 was declared inoperable after failing a self controlled check source test.
Troubleshooting begen promptly in an i
effort to return the monitor to service prior to the expiration of the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> i
reporting 'ime limit-specified in the plant's TS.
In parallel with the repair ef forts, the pre-planned alternate method of monitoring specified in TS 3.3.3.1 was initiated. After ruling out more likely causes of failure, such as the check source operating mechanism and the high range detector pre-amplifier, the investigation determined that the high range detector had failed. After the cause of failure was determined, there was insufficient i
time to complete the re)lacement and calibration of the new high range detector within the 72 lour time frame.
Had the detector replacement been commenced initially upon monitor inoperability, the calibration still could not have been completed within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Xe-133 calibration gas is required for the calibration and must be ordered, since~ the shelf life is limited. There is approximately a one week lead time to obtain the. required calibration gas.
In this instance an expedited order was placed on August 13, 1992, with delivery on August 20, i
1992.
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9208280331 920827 r
PDR ADOCK 0S000361
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U. S. Nuclear Regulatory Commitsion. August 27, 1992 i
I The high range detector was replaced and calibration was commenced after j
receipt of the required calibration gas.
The monitor was returned to operable status on August 25, 1992.
If you.have any questions, please contact me, j;
.Very truly yours, 1
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cc: ' J. B. Martin, Regional Administrator, NRC Region V i
M. B. Fields, NRC Project Manager, San Onofre Units 2 and 3 l
C. W. Caldwell, NRC Senior Resident Inspector, San Onofre j
Units 1, 2, and 3 t
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