ML19210E428
| ML19210E428 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 11/16/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| NUDOCS 7912050024 | |
| Download: ML19210E428 (1) | |
Text
/
'o UNITED STATES E
y, ( [,,g NUCLEAR REGULATORY COMMISSION G.h" ". ' /... [E REGION I 9,
631 PARK AVENUE
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,o KING OF PRUSSIA, PENNSYLVANIA 19406
+.**
Docket No. 50-213 NOV 16 1979 Cor,necticut Yankee Atomic Power Company ATTN:
Mr. W. G. Counsil Vi a President - Nuclear ErJ neering and Operations i
P. O. Box 270 Hartford, Connecticut 06101 Gentlemen:
The enclosed IE Circular No. 79-22, " Stroke Times for Power Operated Relief Valves," is forwarded to you for information.
No writtan response is required.
Should you have any questions related to your understanding of this matter, please contact this office.
Sincerely,
?
lBoyce H. Grier m---
' Director
Enclosures:
1.
IE Circular No. 79-22 2.
List of Recently Issued Circulars CONTACT:
D. L. Caphton (215-337-5263) cc w/encls:
R. Graves, Plant Superintendent D. G. Diedrick, Manager of Quality Assurance J. R. Himmelwright, Licensing Safeguards Engineer 1500 225 29uosooLt
ENCLOSURE 1 SSINS:
6830 Accession No.:
7908220142 UNITED STATES NUCLEAR REGULATORY COMMISSION 3'
D 9
T 0FFICE OF INSPECTION AND ENFORCEMENT J
WASHINGTON, D. C.
20555 UM AJ m
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 systein 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 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 interval without exercise resulted in poor performance of the PORVs.
Recommended Actions for Licensees' Consideratioa:
All holders if PWR om rating licenses or construction permits should be aware of the potential ptvolem 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 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.
1500 226
ENCLOSURE 2 IE Circular No. 74-22 Date:
November 16, 1979 Page 1 of 1 RECENTLY ISSUED CIRCULARS Circular Subject First Date Issued To No.
of Issue 79-13 Bursting of High Pres-8/8/79 All Materials Priority sure Hose and Malfunc-I, Fuel Cycle and Opera-tion of Relief Valve "0" ting Power Reactor Ring in Certain Self-Licensees 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 8/14/79 All Power Reactor 58-12 Switches on Licensees with an OL General Electric or CP Metalclad Circuit Breakers 79-18 Proper Installation of 9/10/79 All Power Reactor Target Rock Safety-Licensees with an OL Relief Valves or CP 79-19 Loose Locking Devices 9/13/79 All Power Reactor Licensees on Ingersoll-Rand Pumps with an OL or CP 79-20 Failure of GTE Sylvania 9/24/79 All Power Reactor Licensees Relay, Type PM Bulletin with an OL or CP 7305, Catalog SU12-11-AC with a 120V AC Coil 79-21 Prevention of Unplanned 10/19/79 All Power Reactor Licensees Releases of Radioactivity with an OL or CP 1SrJD 227