ML18026A870
| ML18026A870 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/16/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18026A869 | List: |
| References | |
| IEB-80-11, TAC-42873, NUDOCS 8402060144 | |
| Download: ML18026A870 (3) | |
Text
WASHINGTON, D. C. 20555
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UNITED STATES N
CLEAR REGULATORY COMMISSION
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING MASONRY HALL DESIGN IE BULLETIN 80-11 BROWNS FERRY 'NUCLEAR PLANT UNITS 1, 2
AND 3 DOCKET NOS. 50-259/260/296 The findings reported in thjs Safety Evaluation Report (SER) are based on the attached Technical Evaluation Report (TER) prepared by Franklin Research Center (FRC) as a contractor to NRC.
This TER contains the details of construction techniques
- used, technical information reviewed, acceptance
- criteria, and technical findings with respect to masonry wall construction at Browns Ferry units.
The staff has reviewed this TER and concurs with its technical findings.
-The following is our summary of major technical findings.
( 1)
The Browns Ferry units contain 7 1. safety-related masonry
'walls which serve as shield walls and/or partition walls.
'The following four types of masonry construction were identified at these units:
(a) reinforced; (b) unreinforced hollow core; (c) unreinforced solid shield block with mortared joints, and (d) unreinforced solid shield block with non-mortared or partially mortared joints.
The type of construction identified in Item (d) is uncoIImon in nuclear power plant facilities.
This issue is further discussed in the Item (3) below.
(2)
The criteria used by the licensee for the re-evaluation of mortared wall's either comply with or meet the intent of the staff acceptance criteria.
(3)
Except for four walls. (designated by Nos. 3, 40, 74 and 75),
all unmortared walls are being upgraded to protect the safety systems around them.
There are no safety-related attachments on the solid shield block walls.
The four walls which have not been upgraded are qualified on the basis of a wall stability analysis..
The staff, based on the FRC and FRC consultants'eview findings (see Section 3..1 of the TER for technical details),
has concluded that the sole use of the wall stability analysis to demonstrate the design adequacy of these four walls is not acceptable.
The staff furth'er conclude that the implementation of the following staff position is required to render these walls acceptable to the staff:
"These walls should be upgraded such that they incorporate structural elements capable of resisting tensile stresses and can be analyzed by the use of the 8402060144 840iih PDR ADOCK 05000250 8
conventional working stress method to demonstrate their conformance with the staff acceptance criteria (Appendix A of the TER).
Alternatively, measures should be provided to protect the safety systems which may be affected by the failure of these walls."
(4)
The licensee has identified 19 walls as requiring fixes.
The staff has reviewed the licensee's modification schemes for these walls and find them acceptable (see Section 3.2 of the TER), as the modified walls are shown to have either satisfied the intent of the staff acceptance criteria or adopted appropriate measures to protect the safety systems from the potential effects of wall failures.
Based on the above findings, the staff concludes that, with the exception of the four walls requiring
~ implementation of the staff position as discussed in Item (3) of this SER, the Items 2(b) and 3 of IE Bulletin 80-11 have been fullly implemented at Browns Ferry Units and there is a reasonable assurance that the safety-related masonry walls at Browns Ferry Units wi 11 withstand the specified design load conditions without impairment of (a) wall integrity or (b) the performance of reauired safety functions.
Principal Contributor:
N. Chokski Dated:
January 16, 1984
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