ML20079C776
| ML20079C776 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 06/21/1991 |
| From: | Piet P COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9106260083 | |
| Download: ML20079C776 (2) | |
Text
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[
h Ccmmenwealth Edison
) 1400 Opus Place
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~ ' ~J Downers Grove, Ulinois 60515 q
\\_ j June 21, 1991 U.S. Nuclear Regulatory Commission Attn:
Document Control Desk Hashington, D.C.
20555
SUBJECT:
LaSalle County Station Units 1 and 2 Supplement to CECO's Response to Inspection Report 373/90022 and 374/90023 NRClocke.tlo1J0-H3_and_5D-174.
REFERENCES:
(a)
M. A. Ring letter to Cordell Reed dated October 11, 1990.
(b)
P.L. Piet letter to A. Bert Davis dated April 15, 1991.
The purpose of this letter is to submit Commonwealth Edison's (CECO) test results in response to the subject NRC Inspection Report (Reference (a)).
CECO has completed our tests which verify that the subject resistors meet the requirements of Regulatory Guide (RG) 1.97.
In Reference (b), CECO committed to the NRC to test the subject resistors and provide a report outlining the test results by June 30, 1991.
The testing was performed by an independent laboratory (Hyle Laboratories) in conjunction with CECO's cognizant A/E (Sargent & Lundy) on May 22-23, 1991.
The eaulvalent ci' cult of a Reactor Water Level Instrument Loop (821-N026A) was subjected to a series of simulated maximum credible faults.
All testing was performed per pre-approved test specifications using the appropriate test equipment under specified test conditions.
The test specification was designed to accurately simulate conditions that thoroughly test the subject resistors.
Hyle Laboratories reported some minor deviations in the test results from the test specification acceptance criteria.
These deviations were attributeu to electrical noise in combination with other interference such as power-supply ripples or input pressure variation.
The test results (with small deviations outside of the acceptance criteria) showed that the applied credible fault had negligible impact on instrument loop performance.
No noticeable change in appearance of the test circuitry specimens was noted as a result of the test.
The test circuit successfully completed its final functional test performed after subjection to all previous credible fault testing.
In addition, the test results showed that the worst case credible fault had,o impact on circuit performance.
CECO's Engineering Department has performed an in-depth review of the test results and has concluded that the l
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6 U.S. Nuclear Regulatory Commission June 21, 1991 postulated credible faults will not degrade the subject Class lE circuit (with 22 kohm resistors performing an isolation function for the non-Class lE Startrec System) below an acceptable level.
The satisfactory test results therefore demonstrate that the subject circuit meets the requirements of RG 1.97.
Please direct any questions you may have concerning this matter to this office.
Very truly yours, d
Peter L. Piet Nuclear Licensing Administrator PLP/cag ZNLD/1022/#
cc:
A. B. Davis, Regional Administrator - RIII B. Siegel, Project Manager - NRR T. Tongue, Senior Resident Inspector - LSCS