ML20133C101
| ML20133C101 | |
| Person / Time | |
|---|---|
| Issue date: | 11/07/1984 |
| From: | Dircks W NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Asselstine J NRC COMMISSION (OCM) |
| Shared Package | |
| ML20132B257 | List: |
| References | |
| FOIA-85-199 NUDOCS 8507200438 | |
| Download: ML20133C101 (1) | |
Text
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[ g NUCLEAR REEULATORY COMMISSION g j WASHINGTON, D. C. 20566
%,..../ NOV 0 71984 MEMORANDUM FOR: Comissioner James K. Asselstine FROM: William J. Dircks Executive Director for Operations
SUBJECT:
CONSIDERATION OF MARK II BWRs IN ACCIDENT SOURCE TERM REASSESSMENT This is in response to your memorandum of October 23, 1984 on the above-captioned subject. Although the reference to contractor calculations in SECY-84-395 does not specifically refer to Mark II BWRs, the Mark II type of vapor suppression containment is not being excluded from source term considerations.
The omission of the Mark II plants from the contractor calculations reported in BMI-2104 arises from the historical developments of this projcct briefly sum-marized below.
The intent of the BCL calculations reported in the contractor report BMI-2104 was to demonstrate the new source term methodology arising from the fission product behavior modeling described in NUREG-0772 (1980). The number and type of plants, as well as the limited number of specific accident sequences selec-ted for analysis were b'ased on the consideration of the diversity of plant and sequence, such that the methodology would be exercised for a wide spectrum of conditions. The environment for fission product behavior in Mark II plants was not considered to be markedly different from the environment presented by the Mark I design, and therefore, was omitted.
As the results of the contractor calculations became available and were exoosed to expert peer review, it became apparent that the overrriding factor in source term estimation is containment integrity, particularly the timing and mode of containment failure. Since the containment loading and response may be more sensitive to specific design details, additional containment designs, including a Mark II containment (i.e., Limerick) were added to the list of calculations to be perfonned by the contractor. Because of the timing of these contract modif-cations, however, the results of the Limerick calculations are not included in the BMI-2104 report. The results of the Mark II calculations, as well as other additional contractor calculations, will be sumarized in the staff's assessment of accident source terms in NUREG-0956.
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BELAIRBS-199 Wil iam J. Di cks Executive Director for Operations cc: Chairman Palladino Comissioner Roberts Comissioner Bernthal Commissioner Zech SECY OGC OPE
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