ML19345G128
| ML19345G128 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 06/18/1973 |
| From: | Searls F PACIFIC GAS & ELECTRIC CO. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 4005, NUDOCS 8103020679 | |
| Download: ML19345G128 (2) | |
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Attention:
Director, Directorate of Licensing Re:
Docket No. 50-133 License No. DPR-7 Section C.4. (a)
Gentlemen:
Pursuant to Section IX.H.2.b. (2) of Appendix A to the Humboldt Bay Unit No. 3 Facility Operating License, we are hereby notifying you of the failure of the cleanup pump motor.
On May 20, 1973, the Unit was in normal power operation.
The cleanup pump was secured to replace depleted cleanup deminer-alizer resins.
Approximately 30 minutes after the pump shaft had stopped rotating, the shaft seals began to discharge a small amount of steam in the area of the pump.
When the pump was returned to service the leakage subsided and the pomp ran normally.
After ap-proximately 20 minutes of operation two arc flashes were observed in the vicinity of the pump, and the motor tripped on overcurrent.
An inspection revealed electrical arc tracking around the motor ventilation louvres, and it is surmised that one or more windings failed as a result of moisture accumulated while the seals were discharging steam.
The loss of the pump does not render the cleanup system inoperable.
As in previous cases when the cleanup pump was out of service due to excessive seal leakage, the demineralizer effluent can be valved to the condenser hotwell instead of the reactor, utilizing the pressure differential. between the reactor and the hot-well to operate the system.
Thus water quality will be maintained within license limits during normal operation.
The control rod hydraulic pumps (one of which is on the emergency power bus) may also be used to operate the cleanup system as a back up to the P00R ORIGINAL gm g g,
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o U. S. Atomic Energy Commission 2
June 18, 1973 core spray system during post-incident decay heat removal operations.
Nevertheless, the loss of the cleanup pump does constitute a variance from the performance specifications contained in the Technical Speci-fications, specifically Sections III.A.3.d(2) and IV.A.4.
Accordingly, we consider the loss of the pump to be an unusual event as described in Section IX.H.2.b. (2).
Because the radiation levels in the vicinity of the pump
-ore relatively high during plant operation the motor was not removed for inspection and repair until the reactor maintenance outage of June 13-15, 1973.
The motor will be subsequently repaired or re-placed as necessary.
We expect to return the pump to service before the Cycle 9 startup currently scheduled for September 1973.
Very truly yours, s
s a
CC: U. S. Atomic Energy Commission Directorate of Regulatory Operations, Region V 2111 Bancroft Way Berkeley, California 94704
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