ML20005E479
| ML20005E479 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 12/28/1989 |
| From: | Cockfield D PORTLAND GENERAL ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9001050312 | |
| Download: ML20005E479 (2) | |
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David W. Cockfield Vice President Nuclear December 28, 1989 Trojan Nuclear Plant Docket 50-344 License NPF-1 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington DC 20555
Dear Sirs:
Anticipated Transient Without Scram (ATWS)
Mitigating System Actuation Circuitry (AMSAC)
By letters dated April 13, 1988, October 3, 1988, and October 31, 1989 Portland General Electric Company specified certain connitments for the design of AMSAC. Unless superseded in one of the subsequent letters, commitments made in these letters continue to be valid. The following statements provide clarification of the commitments made:
1.
Regarding diversity, there is no power supply for the IE section of the isolators used in AMSAC, so no IE power supplies are required. The non-1E sections of the isolators are powered from non-1E sources.
2.
Whenever the C20 limit is referenced, the actual source of the signal will be directly from the turbine first-stage pressure transmitter and not from the output of the Hagan System.
This assures diversity.
3.
Operating and maintenance bypasses are continuously indicated in the Control Room using the "AMSAC TROUBLE" annunciator. The operator would be required to go to a back panel to distinguish which bypass was generating the alarm, or use the alarm video terminal or sequence of events printout.
4.
The testability commitment in the April 13, 1988 letter remains valid.
The comments in the October 31, 1989 letter regarding testability refor to exact procedural development to implement the testability commitment.
5.
The time delay values listed in the October 3, 1988 letter should be considered nominal (not exact) until design work is complete.
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The logic shown in Figure 1 of the April 13, 1988' letter is: correct, but test switches and alarm points are only preliminary.. Final test
- switch and alarm locations will support the testability connitments made.
Sincerely, c:
M'r. John B. Martin
-Regional = Administrator. Region V
,U.S. Nuclear Regulatory Commission Mr. David Stewart-Smith State of Oregon Department of Energy
~Mr. R. C. Barr
.NRC Resident Inspector
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