ML19210E040
| ML19210E040 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay, Diablo Canyon |
| Issue date: | 11/16/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| Shared Package | |
| ML19210E041 | List: |
| References | |
| NUDOCS 7911290195 | |
| Download: ML19210E040 (1) | |
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UNITED STATES
~$.(,,- (*' j NUCLEAR REGULATORY COMMISSION r.
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cC REGION V 9,1 -.h E
1990 N. CAllFORNIA BOULEVARD
,o SUITE 202, WALNUT CREE K PLAZA
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WALNUT CREEK, CALIFORNI A 94596 November 16, 1979 Docket Mos. 50-133, 50-275 50-323 Pacific Gas and Electric Company 77 Beale Street San Francisco, California 94106 Attention: Mr. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
The enclosed IE Circular No. 79-22 is forwarded to you for information. No written response is required. Should you have any questions related to your understanding of this matter, please contact this office.
Sincerely, e
i f.gv R. H. Engelken 0
Director E nclosures:
1.
IE Circular No. 79-22 E.
Recently Issued IE Circulars cc w/ enclosures:
W. Baer, PG&E W. Raymond, PG&E R. Ramsay, PG&E, Diablo Canyon E. Weeks, PG&E, Humboldt Bay J. Worthington, PG&E 3433 356 7911290 A
SSINS: 6830 Accession No.:
7908220142
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UNITED STATES ld MUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 November 16, 1979 IE Circular No. 79-22 STROKE TIf1ES FOR POWER OPERATED RELIEF VALVES Description of Circumstances:
Most PWRs utilize power-operated relief valves (PORVs) to prevent overoressuriza-tion of the reactor coolant systen when the reactor is at low temperature. On April 13, during a cressure transient at Robinson 2, the PORVs did not functicn as rapidly as intended. The estimated stroke time for the PORVs was three to five s conds whereas the intended stroke time is two seconds. As a result, the ores-a sure transient did acoroach a cressure limit which is based on nil ductility considera tions. Prior to April 13, the PORVs had not been used or exercised since February,1978, when they had been repacked and stroked. Although the valve stens were. scored at that time, stroke times were satisfactory. The licensee and the valve manufacturer believe that the scored stems and the 14-month interval without exercise resulted in poor perfomance of the PORVs.
Recomended Actions for Licensees' Consideration:
All holders of PWR operatino licenses or construction oemits shoulc be aware of the ootential problem of the type discJssed above.
Because of the generic imolications in this matter, it is reconnended that both licensees of operating facilities and holders of construction pemits conduct a review to determine if periodic serveillance of PORVs is necessary to assure that the PORVs will perfom as intended.
No written response to this Circular is required.
If you require additional inforration reoardino these matters, contact the Director of the accropriate NRC Reofonal Office.
1433 357 A
IE Circular No. 79-22 Enclosure November 16, 1979 RECENTLY ISSUED IE CIRCULARS Circular Subject n te of Issued to a
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Issue 79-21 Prevention of Unplanned 10/19/79 All holders of Power Releases of Radioactivity Reactor OLs and cps 79-20 Failure Of GTE Sylvania Relav 9/24/79 All utilities having a Tyoe PM Bulletin 7305, Cataloc CP SU12-11-AC With A 120V AC Coil 79-19 Loose Lockinc Devices on 9/13/79 All Power Recctor Ingersoll-Rand Pumps Operating facilities and all utilities having a CP 79-18 Proper Installation of 9/10/79 All Holders of a Target Rock Safety-Relief Power Reactor OL Valves or CP 79-17 Contact Problem in 58-12 8/14/79 All Power Reactor Switches on General Electric Licensees with o C" Conoany Metalclad Circuit and/or OL Breakers 79-16 Excessive Radiation Exposures 8/16/79 All Radicaraphy To " embers Of The General Public Licensees And A Radicaracher 79-15 Bursting of High Pressure Hose 8/8/79 All Materials Priority I, and Mal #urction of o lief Fuel Cycle and Ooerating e
Valve "0" Rino in Certain Self-Power 9eactor Licensees Contained Breathina Apparatus 79-la Unauthorized Procurement and 7/13/79 All "edical Licensees Distribution of XE-133 exceot Teletherachy Medical Licensees and to all Radiocharmaceu-tical Sunolfers
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