ML20138Q996
| ML20138Q996 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 12/23/1985 |
| From: | Nauman D SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8512300179 | |
| Download: ML20138Q996 (2) | |
Text
South C:rollra Electric & Gas Company Dan A. N:uman P.O. Box 765 Vice Presioent Colurrbia, SC 29218 Nuclear operations 9
(803) 748-3513 SCE&G
~~
December 23, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Comission Washington, DC 20555
Subject:
Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 SPDS Digital Isolator
Dear Mr. Denton:
By a letter dated April 18, 1985 from Mr. O. W. Dixon, Jr., to Mr. H. R. Denton, South Carolina Electric and Gas Company (SCE&G) provided responses to NRC Staff questions on the Virgil C. Summer Nuclear Station Safety Parameter Display System (SPDS). As a result of further NRC review of that submittal, a question was raised about one of the qualification tests for the Rochester Instrument digital isolators.
This letter is hereby provided in response to that NRC Staff concern.
Test number two described on page 3 of Attachment A to the April 18, 1985 letter was determined by the NRC Staff to be an inadequate test for isolation for the digital isolators being used at the Virgil C. Summer Nuclear Station. Therefore SCE&G requested further test data from the isolators' manufacturer. As a result, the data resulting from the test set-up shown in Attachment A to this letter was provided to SCEuG by the manufacturer. This data supports that, even in the event of the maximum postulated credible fault which these isolators would be exposed to at the Virgil C. Sumer Nuclear Station, isolation is maintained between the non-1E and 1E outputs and inputs of the system as described in the April 18, 1985 letter.
If you have any fbrther questions, please advise.
Very tr
- ours, N
D.
"a AMM: DAN:tdh c:
V. C. Summer R. A. Stough
- 0. W. Dixon, Jr./T. C. Nichols, Jr.
G. Percival E. H. Crews, Jr.
R. L. Prevatt W. A. Williams, Jr.
J. B. Knotts, Jr.
J. N. Grace NPCF Group Managers File
/
I C. A. Price I,
s,h, ((N[
- 0. S. Bradham C. L. Ligon (NSRC) e44 e312300179 851223 DR ADOCK 0500 5
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i ATTACH)ENT A 14 V
+
.-M-I J
KA sw 3 ________________c EI 4401 l
19 VDC.
I,o).4.c WLk
',,,,i, l4O VDC or y- - - - -
p \\31. VAC
@ 50.-p i*
tow to low I
hpA VM I
(IE)
Dulod (non \\E)
Results:
140 VDC Tests - Relay contacts on non IE s ide of isolator module fused closed. Circuit traces opened.
Isolation was maintained.
132 VAC Tests - Relay contacts remained undamaged. Circuit traces opened.
Isolation was maintained.
i i
.