ML19345G112
| ML19345G112 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 11/27/1974 |
| From: | Searls F PACIFIC GAS & ELECTRIC CO. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 12144, NUDOCS 8103020462 | |
| Download: ML19345G112 (2) | |
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77 BEALE STREET
- SAN F R A N CISCO, C ALIFO R NI A 94106 * (415) 781 4211 P R IE D E R I C K T. S E A R L S mees seuw November 27, 1974
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Director Directorate of Licensing
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Office of Regulation U. S. Atomic Energy Commission COCKE D s
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Docket No. 50-133 License No. DPR-7 m"prM
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Humboldt Bay Power Plant 9
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Dear Sir:
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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 damage to four core spray nozzle locking straps.
On October 30, 1974 the reactor was shutdown for a l
regularly scheduled refueling outage.
On November 1, 1974 during l
a routine inspection of the reactor vessel head, including the core spray ring and nozzles, it was noted that the locking straps which prevent the spray nozzles from unscrewing were broken on four of the twenty spray nozzles.
None of the nozzles with broken straps had started to unscrew or were damaged.
The spray nozzles extend down through the plane of the reactor head flange and are located inside the react or head storage fixture when the head is off the reactor vessel.
Inspection of the storage fixture after the discovery of the broken locking straps and prior to storage of the head revealed that its plastic cover was damaged at the points where the nozzles with broken straps had been located.
Therefore, it appears that the nozzles contacted the storage fixture when the reactor head was being lifted from the storage fixture in preparation for installation on the reactor vessel at the end of the last refueling outage in September 1973.
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l Director November 27, 1974 Directorate of Licensing U. S. Atomic Energy Commission Page 2 All locking straps were inspected and the'four faulty straps rewelded to firmly lock the nozzles in place.
The reactor vessel held installation procedure is being changed to require inspection of the spray ring and nozzles 'just before instr llati ;n.
The reactor head handling equipment has been modified to stabia.ize the vessel head when it is lifted from its storage fixture.
This is the first instance of this type of damage.
Very truly yours,
/R rahAo CC:
Mr. R. H. Engelken, Director Directorate of Regulatory Operations Region V i
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