ML20064K766
| ML20064K766 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Robinson |
| Issue date: | 10/27/1978 |
| From: | Dance H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML082180535 | List:
|
| References | |
| FOIA-82-261 NUDOCS 8106220165 | |
| Download: ML20064K766 (2) | |
Text
,a a tt UNITED STATES N NUCLEAR REGULATORY COMMISSION!N 4.,
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ATL ANTA. GE oRGI A 00303 OCT 2 7 1978
& c./ocure 1 SSINS 9150 MEMORANDUM FOR:
E. L. Jordan, Assistant Director for Technical Programs, Division.of Reactor Operations, IE:HQ THRU:
. J. Long, Chief, Reactor Operations and Nuclear Support Branch, Region II FROM:
H. C. Dance, Chief, Reactor Projects Section No.1,
- RONS Branch, Region II SU3J ECT
- --
EXCESSIVE LEAKAGE OF CONTAINMENT PURGE VALVES (AITS F24091H2)
Recent inspection findings at the H. B. Robinson 2 facility indicate that the current surveiLL'ance requirements f6r containment purge valves at all facilitics may not be adequate.
The 1977 annual report for the H. B. Robinsori 2 facility indicated a high frequency of adjustcents to the containment purge valves togorrect exces-sive Leakage.
A discussion with.the Licensee concerning the apparent
' problem with preper sealing of containment purge valves revealed the following information:
1.-
During a one year period, from June 1977, there were 15 dccumented work packages for maintenance adjustments of containment purge valve seats.
2.
The Licensee e.stimated that the excessive Leakage c'endition occurred at a frequency of one. time for every five valve cycles.
(i.e., open and shut equats one cycle) 3.
The Licensee assessment of the leakage problem resulted in the conclusion that there are no permanent corrective measures available to reduce the frequency of excessive leakage.
This conclusion is based on the fact that these valves are 42 inch butterfly type with I
resilient seals and a closure time of 2 seconds.
Therefore, with a l
Very low leakage limit, periodic " excessive leakage" is inherent with this type of valve.
4.
Once properly sealed, purge valves maintain proper sealing while they remain closed.
The excessive leakage occurs when valves do not seal properly following valve closure.
[ /OOprO/ c/
2 CONTACT:
T. J. M: Henry
/
242-5565
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E. L. Jordan -
5.
The H. B. Robinson 2 facilit'y has a Penetration Pressurization System which automatically pfessUFizef the inner space between the inner and outer purge valves.
Therefore valve leakage is detected shortly after closure such that adjustments can be made by maintenance personnel to restore the leakage within the allowance by Technical Specifications.
6.
Many f acilities built after H. B. Robinson 2 do not have a Penetration Pressurization System.
Therefore excessive leakage of containment purge valves can only be detected by the local leak rate testing performed at refuel.ing intervals.
- 7..',The H. B. Robinson purge valves are supplied by Allis-Chalmers Mfg.
Company,.Model 50 FR' Stream Seal Valve.
Based upon the above information, periodic excessive leakage of contain-ment purge valves caused by valve cycling may be an inherent problem at any: facility with a similar type of valve.
In addition, the assumption
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that excessive leakage through containment purge valves will not occur between refueling interval testing does not'. appear valid.
The above information indicates that the leak te. sting required by the Technical Specifications may not,be adequate for facilities without a Penetration, Pressurization System.
Therefore an evaluation should be made to determine.if the present frequency of leak rate testing con-tainment purge valves is adequate to assure. containment integrity.
H. C. Dance, Chief Reactor Proj ects Section No. 1
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.cc:
R. D. Martin P. J. Kellogg R. C. Lewis D. Neighbors, DDPM:HQ O
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