ML20091R677

Forwards Response to Commitment in SER,NUREG-0979,Section 7.2.2.2 Re Design Verification Testing of Optical Isolators

ML20091R677
Person / Time
Site:	05000447
Issue date:	05/30/1984
From:	Sherwood G GENERAL ELECTRIC CO.
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
RTR-NUREG-0979, RTR-NUREG-979 MFN-073-84, MFN-73-84, NUDOCS 8406150203
Download: ML20091R677 (2)

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, GENERAL ELECTRIC NUCLEAR POWER SYSTEMS DMSION GENERAL ELECTRIC COMPANY e 175 CURTNER AVENUE

• SAN JOSE, CAUFORNIA 95125 May 30, 1984 MFN# 073-84 U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington D.C. 20555 Attention: Mr. D. G.-Eisenhut, Director-Division of Licensing

SUBJECT:

IN THE MATTER OF 238 NUCLEAR ISLAND GENERAL ELECTRIC STANDARD SAFETY ANALYSIS REPORT (GESSAR II) DOCKET NO. STN 50-447 Verification Testing of Optical Isolators Attached please find response to GE commitment in Section 7.2.2.2 of Safety Evaluation Report NUREG-0979 regarding design verification testing of optical isolators.

The information is provided at the request of M. J. Virgilio, ICSB.

Sincerely, l

I f G enn G. Sherwood, Manager Nuclear Safety and Licensing Operation GGS: cal:rm/K053012*

Attachments cc: M. J. Virgilio, NRC D. C. Scaletti, NRC L. S. Gifford, GE-Bethesda (w/o att.)

F. J. Miraglia (w/o att.)

C. O. Thomas (w/o att.)

R. M. Ketchel (w/o att.)

R. W. Strong D. L. Foreman e4ou ,n n .4o,,o PDR ADOCK 05000447 E PDR

(.

. 't The optical isolators used in the GESSAR II design fully comply with the requirements of Regulatory Guide 1.75. Each divisional chamber contains only wiring and equipment associated with that specific division. Each chamber is enclosed by metal barriers also in accordance with the guide.

Therefore, any individual failure of card or component can at most affect only equipment within the same chamber, which is the same divisie6. The single-failure criterion is thus preserved regardless of the optical isolators capability to withstand line-to-line or line-to ground faults.

Such capability is of interest for reliability and system availability evaluations, but is not pertinent for safety evaluations because of the isolation and redundancy provided in the design.

GE has designed the cards for high reliability, v51ch includes tolerance of abnormally high voltages on the input gates. This is accomplished by high impedence resistors which limit input currents to non-destructive levels. The 12-volt logic input pins of sample carcs were subjected to the following overrange voltagas for the time durations shown:

DC Volts Temperature Time 150 Ambient 2 minutes 400 Ambient 1 millisecond (pulse)

After applying a 150-volt DC signal to the inputs for two minutes, the card was determined to be functioning properly. The 400 volt, 1 millisecond pulse was then applied at the inputs and verified on the oscilloscope.

Following the application of the pulse, the card was still functioning normally.

t RWS: cal: rm/K053013*

5/30/84

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