ML20149G052

Informs That Anonymous Friend of Author in Utility Suggests That AEC Better Look Into Potential for common-mode Failures in Instrumentation & rod-drive Systems

ML20149G052
Person / Time
Site:	Browns Ferry
Issue date:	07/11/1973
From:	Hanauer S US ATOMIC ENERGY COMMISSION (AEC)
To:	Hendrie J, Ippolito L, Stello V US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20149G041	List: ML20149G037 ML20149G048 ML20149G052
References
NUDOCS 9707220417
Download: ML20149G052 (1)

Text

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• ATOMIC ENERGY COMMISSION

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July 11,1973

• J. M. Hendric, L V. Stello, L T. Ippolito, L POTEFTIAL SYSTEMS FOR C0'DION-MODE FAILURES IN INSTRO!ENTATION AND ROD An anonymous friend of mine in a utility .sugr,ests that we had better look into the follouing:

1.

i Impulse lines (small pipes connecting the big process pipes to ,.

transducers for pressure, flow, level) appear to be.run without sufficient regard to their possible vulnerability to the acci-dent for uhich they are supposed to provid.s protectiun. As exampics, failure of a primary pipe or a steam line could wipe

' out redundant channels of protective instrumentation by break- '

ing or pinching redundant impulse lines. This would appear to be forbidden by IEEE-279, but my informant assures me that examples of vulnerability are apparent. *

2. The discharge pipes from GE rod drives must be open (to the scram discharge volude) to allow the rods to scram. One such pipe leads from each of,~<200 rod drives. They are run in bundles without apparent regard to vulnerability to kinking and pinching from whipping broken pipes and such. edjacent rods are bundled in such a way that pinching off a number of pipes in one bundle will make the reactor supercritical on injection of cold ECCS water. '

It seems to me that these potential problems are indeed worth looking into. -

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S. H. Hanauer, DRTA  ;

i cc: L. Rogers, RS E. G. Case,.L i i

D. F. Knuth , RO )

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