ML19345G111
| ML19345G111 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 12/06/1974 |
| From: | Searls F PACIFIC GAS & ELECTRIC CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| IEB-74-14, NUDOCS 8103020456 | |
| Download: ML19345G111 (2) | |
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PACIFIC GAS AND E LE C T RIC C O M PANY FO*Mb l
77 B E ALE S T R EET. S A N F R A N CISCO, C ALIFO R NI A 94106. (415) 781 4211 w e. ssue P R E D E RIC K T. S E A R LS December 6, 1974
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Mr. R. H. Engelken, Director Directorate of Regulatory Operations Region V g
/'0 1990 N. California Boulevard
'h O Walnut Creek Plaza, Suite 202
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Walnut Creek, California 94596 DEC 91974 g C
Re:
Docket No. 50-133 g -m,, y i.e License No. DPR-7 gu, t.7 F.EQ.
Humboldt Bay Power Plant
'J' CPERATIONS
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Unit No. 3 b
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Dear Mr. Engelken:
Your letter dated November 15, 1974 with the enclosed Regulatory Operations bulletin No. 74-14 requested that we review our current operating procedures which are applicable to relief valve discharges to the suppression pool to determine if they are
' adequate in certain specific areas.
s Our review indicates that the following areas are ade-quately covered by operating procedures or technical specification limits:
1.
(Item 1.a. of your letter)
Limiting bulk suopression pool temperatures during normal operation and during controllable transients.
Section III.B.10.6. (3) of the Technical Specifications requires that bulk sup-pression pool temperature be less than 90*F at all times during power operation.
2.
(Item 1.b. of your letter)
Recuiring reactor trip M the bulk sunpression pool temperature exceeds that established as a limit for controllable transients or if relief valves fail to reseat properlv.
Operating procedures require that action be taken to investigate and correct abnormal increases in suppression pool temperature and to initiate a controllable reactor shut-down b fore suppression pool temperature reaches 90*F.
nosoa" P00R ORIGINAL
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I Mr. R. H. Engelken 2'
December 6, 1974 P
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Since discharges to the suppression pool are not ex-pected to occur during normal plant transients it is believed that a controlled reactor shutdown is suf-ficient and a reactor trip is not required.
Humboldt Bay Power Plant has two automatic vent valves, but they are only initiated if a loss of coolant accident or main steam line break outside of containment occurs, and they are not designed for use during normal transients.
Normal transients are handled by the full capacity turbine bypass valves that discharge to the main condenser.
3.
(Item 1.e. of your letter) conduct of[ visual internal and external inspection cg[ sumeression pool structure for evidence of damage in instances where one or more relief valve (s) fails to reseat properly or discharges tgt the suporession pool for an extended period of tbme.
Section III.B.6. of the Technical Specifications requires that a thorough inspection be made of the suppression chamber following any full capacity safety valve discharge.
We also interpret this to mean any full capacity vent valve discharge.
In responding to Items 1.c. and 1.d. of your letter, operating procedures will be reviewed in the following areas and appropriate revisions made in order to minimize the effect of steam discharge to the suppression pool:
1.
Requiring a reactor shutdown if a safety valve fails to rescat properly and damage to the suppression pool could result from continued discharge.
2.
Taking prompt steps in case of inadvertent safety valve actuation or failure to reseat to minimize the duration of steam discharge.
4 I
3.
Promptly initiating suppression pool circulation to dissipate local peaking of water temperatures in cases of safety valve discharge.
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These procedural changes will be made so that they will not have an adverse effect on other areas of plant operation and i
will be completed by February 1,1975.
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very truly yours,
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