ML19248D392
| ML19248D392 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/27/1979 |
| From: | Rehm T NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Helfman S PRESIDENT'S COMMISSION ON THE ACCIDENT AT THREE MILE |
| References | |
| NUDOCS 7908150729 | |
| Download: ML19248D392 (2) | |
Text
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27 s-JUL, ?
1979 July 26,1979
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Mr. Stan Helfman President's Cormiission on TMI 2100 M Street..N.W., Suite 714 Washington, D. C.
Dear Stan:
Attached is the information you requestea from Edson Case, Deputy Director, Office-of Nuclear Reactor Regulation.
Sincerely,
/g Thomas A. Rehm Assistant to ED0 i.1cfosure Background info to 1/10/78 re Loop Seals in Pressurizer Surge Line bcc: Willian Besaw/ADM E. Kevin Cornell /NRC-T?il ED0 R/F 7908156721 c
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israel /lecesco:ca Background Information to January 10, 1978 f;ote to RSB -- Loop Seals in Pressurizer Surge Line The potential effect of loop seals (i.e., a manometer effect) in a pressurizer surge line on pressurizer level indications was considered by fir. S. Isr4el (RSB) back in 1977 as a generic technical matter rather than during the review of any specific plants; however, he did recognize that the loop seal configuration appears to be unique to B&W The nature of the concern for the loop seal deals with plant designs.
behavior as a mano$eter where level changes would be associated with differences g in pressure between the primary system and the pressurizer.
In some transient situations where voids would be formed in the primary This system,thepressu(izermaynotbethehottestpointinthesystem.
Since the could lead to the manometer effect in the pressurizer.
pressurizer is where the instrumentation is installed to measure system coolant level, this situa on could lead to misleadir.g level information.
The operator relies.on level indication for the tantrol of makeup flew to the plant system.
Operating experience available at the time that '.he memorandum ;as prepared did not reveal any situah'}:n for which the operator could not effect safe plant shutdown; consequently, actions to pursue this matter further at the time were not taken.
This has remained generally true up to The experience of the Till 2 accident, makes it apparent that greater now.
emphasis in the review must be given to this matter.
IhL 52)
EWN Lt
._