ML20040A507

Comments on Proposed Removal of Redundant ESF Actuation Sys Signals from B-SAR-205 MSIV Design,Per NUREG-0138.Change Does Not Provide Sufficient Interface Criteria to Assure Signal Compliance W/Ieee Std 279-1971

ML20040A507
Person / Time
Site:	05000561
Issue date:	03/16/1978
From:	Ippolito T Office of Nuclear Reactor Regulation
To:	Cox T Office of Nuclear Reactor Regulation
Shared Package
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References
FOIA-80-515, FOIA-80-555, RTR-NUREG-0138, RTR-NUREG-138 NUDOCS 8201210195
Download: ML20040A507 (1)

Text

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Do UNITED STATES f*'

~*h NUCLEAR REGULATORY COMM!sslON i-I WASHING TON. D. C. 20555

%, **"*f MAR 1 S 1978 MEMORANDUM FOR: Tom Cox FROM:

T. Ippolito, Chief, Instrumentation and Control-Systems Branch, DSS

SUBJECT:

B-SAR-205 DESIGN CHANGE IN MAIN STEAM LINE ISOLATION

~ ~ ~

Babcock and Wilcox has proposed removing the redundant ESFAS signals from ~ ~

~

the MSIV's and thus take full credit for the turbine stop valves in order to close the system following a main steam line break.

NUREG 0138 was referenced in a discussion as the basis for this change.

The NUREG docu-ment does allow credit for turbine stop valves as backup to MSIV's while not requiring the turbine stop. valves to be seismically qualified.

This allowance for the ' turbine stop valves explicitly assumes that the electri-cal aspects of the MSIV's meet the requirements of IEEE Std 279-1971.

This explicit assumption is no longer valid as the redundant ESFAS signal to each MSIV has been removed.

ESFAS actuatien subsystem A now will only signal loop A MSIV's to close and the same for ESFAS actuation subsystem B for loop B.

We, therefore find the proposed design to be unacceptable and require either of the following to be accomplished.

1) Reinstate the redundant ESFAS signal to each MSIV or

2) Provide sufficient interface criteria for the ESFAS signals

~

terminating at the turbine stop valves to assure these sig-nals meet all the requirements of IEEE Std 279-1971.

A

/

. A. II lito, Chief Instrumentation and Control Systems Branch Division of Systems Safety cc:

R. Tedesco C. Miller F. Rosa M. Srinivasan

0. Parr PSS Members D. Vassallo ICSB Members ewbury

Contact:

R. Fitzpatrick 492-7276 8201210195 810403 PDR FOIA MADDEN 80-515 PDR

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