ML19256F369
| ML19256F369 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 11/16/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | William Jones OMAHA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 7912190028 | |
| Download: ML19256F369 (1) | |
Text
CENTRAL FILES PDR:HQ n alcut UNITED STATES LPDR
[e NUCLEAR REGULATORY COMMISSION E
REGION IV Ng}g
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y th,., {i. g 611 RY AN PL AZA DHIVE, SUITE 1000 ARLINGTcN, TEXAS 76012 s %g;tptif p p e.: uppg p November 16, 1979 Docket No.
50-235 Omaha Public Power District ATTN:
W. C. Jones, Division Manager -
Production OparnHons 1623 Earney Street Omaha, Nebraska 68102 Centlemen:
The enclosed IE Circular No. 79-22, is forvarded to you for information.
No written response is raquired.
Should you have any questions related to your understanding of this matter, please contact this office.
Sincerely, l
Karl V.
yfrit Director
Enclosures:
1.
IE Circular No. 79-22 2.
Recently Issued IE Circulars cc:
S. C. Stevens, Manager Fort Calhoun Station Post Of fice Box 98 Fort Calhoun, Nebraska 68102 1625 044 mu oo 02F
SSINS:
6830 Accession No.:
7908220142 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 IE Circular No. 79-22 Date: November 16, 1979 Page 1 of 1 STROKE TIMES FOR POWER OPERATED RELIEF VALVES Description of Circumstances:
Most PWRs utilize power-operated relief valves (PORVs) to prevent overpressuriza-tion of the reactor coolant system when the reactor is at low temperature.
On April 13, 1979, during a pressure transient at Robinson 2, the PORVs did not function as rapidly as intended.
The estimated stroke time for the PORVs was three to five seconds whereas the intended stroke time is two seconds.
As a result, the pressure transient did approach a pressure limit which is based on nil ductility considerations. 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 stems were scored at that time, stroke times were satisfactory. The licensee and the valve manufacturer believe that the scored stems and the 14-month int rval without exercise resulted in poor performance of the PORVs.
Recommended Actions for Licensees' Consideration:
All holders of PWR operating licenses or construction permits should be aware of the potential problem of the type discussed above. Because of the generic implications in this matter, it is recommended that both licensees of operating facilities and holders of construction permits conduct a review to determine if periodic surveillance of PORVs is necessary to assure that the PORVs will perform as intended.
No written response to this Circular is required.
If you require additional information regarding these matters, contact the Director of the appropriate NRC Regional Office.
1625 045
IE Circular No. 79-22 November 16, 1979 RECENTLY ISSUED IE CIRCULARS Circular Subject Date Issued To No.
Issued 79-14 Unauthorized Procurement 7/13/79 All Medical Licensees and Distribution of Except Teletheraphy XE-133 Medical Licensees and to all Radiopharmaceutical Suppliers 79-15 Bursting of High Pressure 8/8/79 All Materials Priority I, Hose and Malfunction of Fuel Cycle and Operating Relief Valve "0" Ring in Power Reactor Licensees Certain Self-contained Breathing Apparatus 79-16 Excessive Radiation 8/16/79 All Radiography Exposures to Members Licensees of the General Public and a Radiographer 79-17 Contact Problem in SB-12 8/14/79 All Power Reactor Switches on General Licensees with a Electric Company Construction Permit Metalclad Circuit (CP) and/or Operating Breakers License (OL) 79-IP Proper Installation of 9/10/79 All Holders of a Target Rock Safety-Relief Power Reactor Operating Valves License (0L) or Construction Permit (CP) 79-19 Loose Locking Devices on 9/13/79 All Power Reactor In8ersoll-Rand Pumps Licensees with a Construction Permit (CP) and/or Operating Licensee (OL) 79-20 Failure Of GTE Sylvania 9/24/79 All Power Reactor Relay, Type PM Bulletin Licensees with a 7305, Catalog SU12-11-AC Construction Permit (CP)
With A 120V AC Coil and/or Operating Licensee (0L) 79-21 Prevention of Unplanned 10/19/79 All holders of Power Releases of Radioactivity Reactor Operating Licenses (OLs) or Construction Permits (cps)
Enclosure 1675 046