ML19210E507
| ML19210E507 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 11/16/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Hines E DETROIT EDISON CO. |
| References | |
| NUDOCS 7912050124 | |
| Download: ML19210E507 (1) | |
Text
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Tertn Docket No. 50-341 The Detroit Edison Company ATTN:
Mr. Edward Hines, Assistant Vice President and Manager Quality Assurance
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Detroit, MI 48226 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, James G. Keppler Director
Enclosure:
IE Circular No. 79-22 cc w/ encl:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Ronald Callen, Michigan Public Service Commission Eugene B. Thomas, Jr.,
Attorney 1498 081 RIII RIII Q,sl Fiorelli/bk Keppler 11/15/79 79120 5 0 /2 J
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6830 Accession No.
7908220142 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 November 16, 1979 IE Circular No. 79-22 7dOKE 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, 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 pres-sure 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 interval 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 serveillance of PORVs is necessary to assure that the PORVs will perform
. 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.
Enclosure:
Recently Issued IE Circulars
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IE Circular No. 79-22 Enclosure November 16, 1979 RECENTLY IS$dED IE CIRCULARS Circular Subject Date of Issued to No.
Issue 79-21 Prevention of Unplanned 10/19/79 All holders of Power Releases of Radioactivity Reactor OLs and cps 79-20 Failurr Of GTE Sylvania Relay 9/24/79 All utilities having a Type P4 Bu.letin 7305, Catalog CP SU12-5.1-AC With A 120V AC Coil 79-19 Loose Locking Devices on 9/13/79 All Power Reactor 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 S8-12 8/14/79 All Power Reector Switches on General Electric Licensees with a CP Company Metalclad Circuit and/or OL Breckers 79-16' Excessive Radiation Exposures 8/16/79 All Radiography To Members Of The General Public Licensees And A Radiographer 79-15 Bursting of High Pressure Hose 8/8/79 All Materials Priority I, and Malfunction of Relief Fuel Cycle and Operating Valve "0" Ring in Certair Self-Power Reactor Licensees Contained Breathing Apparatus 79-14 Unauthorized Procurement and 7/13/79 All Medical Licensees Distribution of XE-133 except Teletheraphy Medical Licensees and to all Radiopharmaceu-tical Suppliers 1498 083