ML20077G160
| ML20077G160 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 07/22/1983 |
| From: | Schroeder C COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 7016N, NUDOCS 8308030397 | |
| Download: ML20077G160 (2) | |
Text
,
\\ one First NItional Plaza, Chicigo. Ilianons Commonwealth Edison a
O
/
O Address Reply to: Post Office Box 767
\\s Chicago, Illinois 60690 July 22, 1983 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
LaSalle County Station Unit 1 30% Rated Thermal Power Based on Turbine First Stage Pressure Interlock Setpoint NRC Docket-No. 50-373 References (a):
License NPF-11, Appendix A, Technical Specification Pages 3/4 3-4, 3/4 3-5, and 3/4 3-41.
(b):
LaSalle Special Test 83-38.
Dear Mr. Denton:
Reference (a) contains footnotes to requirements that the turbine first stage parameters be less than or equal to 140 psig, which state:
" Initial Setpoint.
Final Setpoint to be determined during startup test program.
Any required change to this setpoint shall be submitted to the Commission within 90 days of test completion."
BACKGROUND:
The reactor scram and EOC/RPT due to turbine stop valve closure and turbine control valve fast closure is bypassed automatically at reactor powers less than 30% rated thermal power.
This power level is sensed by monitoring the main turbine first stage pressure with a setpoint of less than or equal to 140 psig.
DISCUSSION:
A test has been completed and reviewed (References (a) and (b)) to determine the turbine first stage pressure verses reactor thermal power.
Using the average pressure of 2 precision Heise pressure gauges this test showed that during a normal reactor and turbine startup, the turbine first stage pressure at 30% rated thermal power is 158 psig (this is with the feedwater heaters on line).
This pressure is well above the Technical Specification setpoint of 140 psig.
(140 psig corresponds in this case to approximately 27.5%
rated thermal power.)
In the worst case, with no feedwater heaters on line (not a normal condition),
the average turbine first stage pressure at 30% rated ggf)g thermal power was 140 psig.
0 P
7---
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H. R. Denton July 22, 1983 CONCLUSION:
This test shows that the setpoint of 140 psig is acceptable as is.
Even in the worst case, this setpoint will provide the appropriate interlock at or before 30% rated thermal power.
Therefore, no Technical Specification changes are required as specified in the footnotes on pages listed in Reference (a).
To the best of my knowledge and belief the statements contained herein are true and correct.
In some respects these statements are not based on my personal knowledge but upon information furnished by other Commonwealth Edison employees and consultants.
Such information has been reviewed in accordance with Company practice and I believe it to be reliable.
Enclosed for your use are one signed original and forty (40) copies of this letter.
If there are any questions in this matter, please contact this office.
Very truly yours, 2.
3 C. W. Schroeder Nuclear Licensing Adminstrator im cc:
NRC Resident Inspector - LSCS 7016N
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