ML20213D873
| ML20213D873 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 10/19/1981 |
| From: | Butler W Office of Nuclear Reactor Regulation |
| To: | Schauer F Office of Nuclear Reactor Regulation |
| References | |
| CON-WNP-0405, CON-WNP-405 NUDOCS 8111130023 | |
| Download: ML20213D873 (1) | |
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MEMORANDUM FOR:
F. Schauer, Chief, Structural Engineering Branch, DE FROM:
W'. Butler, Chief, Containment Systems Branch, DSI
SUBJECT:
REQUEST FOR REVIEW ASSISTANCE: WNP-2 CONTAINMENT DESIGN EXTERNAL PRESSURE i
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The primary containment for WNP-2 is a free-standing steel pressure vessel enclosed in a reinforced concrete biological shield wall and separated by compressible isolation material. The applicant stated that the design ex-ternal differential pressure is 4.0 pounds per square inch. However, since the compressed insulation between the concrete biological shield and the free-standing steel containment exerts a uniform pressure of two pounds per square inch on the free-standing steel containment, the reactor building pressure may be no greater than two pounds per square inch above the primary containment pressure.
The WNP-2 plant is equipped with three reactor building-to-wetwell and nine wetwell-to-drywell vacuum relief valves to ensure that the containment pres-sure will not be less than two pounds per square inch below the reactor build-ing pressure. The analyses provided by the applicant, based on a worst case condition, indicated that the maximum calculated negative overall containment pressure across the containment wall will be less than two pounds per square inch gauge. However, since we believe the margin will be small (our analysis has not yet been completed), we are concerned about the degree of accuracy in determining the pressure exerted on the free-standing steel containment by the insulation. We, therefore, request the Structural Engineering Branch to deter-mine if the uniform pressure exerted by the insulation will not exceed the two pounds per square inch established by the applicant.
If you have any questions regarding this request, contact F. Eltawila (29418).
Original cigned by V;altcrR.Eatier.
Walter R. Butler, Chief Containment Systems Branch Division of Systems Integration cc:
T. Speis R. Tedesco
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