ML20028D289
| ML20028D289 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/29/1982 |
| From: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML20028D290 | List:
|
| References | |
| NUDOCS 8301170292 | |
| Download: ML20028D289 (2) | |
Text
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Q9 Southern California Edison Company 5' zy OE S A N ONO F R E NUC LE A R G EN ER A TINC. S T A T f 0N h[g,,
[O P.O. eO x 12a S AN C LEMENTE, C ALIFORNI A 92672
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H. B. R A Y TELEPHONE December 29, 1982 svar o~ - NaaE a m - mo 1
U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region V 1450 Maria Lane, Suite 210 Walnut Creek, California 94596-5368 Attention:
Mr. R. H. Engelken, Regional Administrator
Dear Sir:
Su bject:
Docket No. 50-361 30-Day Report Licensee Event Report Nos.82-153 and 82-154 San Onofre Nuclear Generating Station, Unit 2 This submittal is in accordance with the reporting requirements of Section 6.9.1.13b of Appendix A to Facility Operating License NPF-10.
It describes two (2) reportable occurrences involving Limiting Condition for Operation (LCO) 3.3.4 associated with the Turbine Overspeed Protection System (TOPS).
Completed copies of LER 82-153 and 82-154 are enclosed, which address these events.
While in Mode 1, on November 30, 1982, following a turbine trip at 1037, low pressure turbine stop valve 2VV-22005, located on Low Pressure Turbine #3, and low pressure turbine stop valve 2VV-2200R, located on Low Pressure Turbine #2, did not close fully.
Consequently, they were declared inoperable, and LC0 3.3.4 Action Statement a was invoked.
As required by this Action Statement, valve 2VV-2200T on Low Pressure Turbine #3 and valve 2VV-2200Q on Low Pressure Turbine #2 were secured in their closed position at 1945 on the same day, isolating the affected steam leads.
Valves 2UV-22005 and 2VV-2200R were again declared operable on December 8, 1982, when surveillance requirement 4.3.4.a was satisfactorily completed.
However, as further investigation of the cause of failure of the low pressure turbine stop and intercept ulves, four of the twelve valves, including 22005 and 2200R, were disassambled and inspected during the current outage.
i 8301170292 821229 PDR ADOCK 05000361 RM S
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a Mr. R. H. Engelken December 29, 1982 Upon disassembly, evidence of galling between the butterfly valve disc stub shaft and casing bore was observed in valves 2200R, S, and V while 2200M appeared only to require cleaning. Measurement of shaft and bore diameters indicated an absolute minimum clearance between shaft and bore in the three valves exhibiting galling.
The stub shafts were machined to provide additional clearance between shaft and bore while remaining within drawing tolerances for each diameter.
The four valves were cleaned and reassembled and cycling tests after reassembly provided no further indication of binding, galling, or erratic valve movement.
The operation of all turbine stop and intercept valves will be closely monitored throughout the remainder of the power escalation test program and corrective action, similar to the above, will be applied to the remaining eight valves as necessary.
Since the requirements of Action statement 3.3.4.a were satisfied as soon as a valve was determined to be inoperable, the possibility of creating a turbine missile that would endanger plant personnel or result in an accident endangering the health and safety of the public was eliminated.
If there are any questions regarding the above, please contact me.
Sincerely, H Sh / ? Tug i
l
Enclosure:
LER 82-153 & 82-154 A. E. Chaffee (USNRC Resident Inspector, San Onofre Unit 2) cc:
U. S. Nuclear Regulatory Commission l
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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