ML20064E271
| ML20064E271 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 11/08/1978 |
| From: | ARKANSAS POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20064E270 | List: |
| References | |
| NUDOCS 7811160063 | |
| Download: ML20064E271 (1) | |
Text
.
INTERIM REPORT LPSI DRAIN LINE WELD FAILURE Description of Deficiency A leak was detected in a drain line weld (GCB-508-1) off L. P. Safety Injection Pump 2P60A on August 16, 1978. Radiographic and Liquid Penetrant Examinations revealed a 3/4 inch linear indication on the 1 inch side of a 1" x 2" reducer running circumferential1y in the fusion zone between weld metal and fitting.
Original records revealed weld had successfully passed Liquid Penetrant Examina-tion and Hydro Testing. As examination of the failed weld was performed.
The examinution, combined with jobsite information, indicates that fatigue was the cause of tailure, possibly the results of excessive cyclical (alternating) stesses from che LPSI pump located within four (4) feet of the subject weld.
It was determined the crack was not associated with material quality or welding process used. Also, no positive evidence was found to support the possiblilty that corrosion fatigue or stress corrosion cracking mechanisms contributed to the failure.
Safety Implication This leak could not have gone undectected for an extended period of. time because the LPSI pump rooms are inspected each shift and the rooms are equipped with safety grade drain level detectors. In the worst case, a non-leaking (therefore undetected) crack, the fitting could have begun to leak during post-LOCA re-circulation.
It is extremely unlikely, though possible, that this leakage could exceed the Sgpm considered in the Final Safety Analysis Report. Leakage of this fitting during a LOCA could reduce LPSI flow from one punp--mostiikely an insigni-ficant amount. Complete failure would be required to reduce the flow as much as 500 gpm and would be within the single failure analysis for this system.
During shutdown cooling operation, a failure of this fitting would result in a loss of reactor coolant inventory and small radiological dose to operators.
781116 Oc6 3
.