ML20070N176
| ML20070N176 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 04/28/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20070N174 | List: |
| References | |
| NUDOCS 9405050198 | |
| Download: ML20070N176 (3) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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SAFFTY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 59 TO FACTU TY OPERATING LICENSE N0 NPF-58 THE CLEVELAND ELECTRIC ILLUMINATING COMPANY. ET AL.
PERRY NUCLEAR POWER PLANT. UNIT NO. 1 DOCKET NO. 50-440
1.0 INTRODUCTION
By letter dated January 19, 1990, the Cleveland Electric Illuminating Company, et al. (the licensee), requested changes to the Technical. Specifications (TSs) for the Perry Nuclear Power Plant (PNPP), Unit 1.
The proposed changes would revise TS 3.3.2, Isolation Actuation Instrumentation, Tables 3.3.2-1, 3.3.2-2, l
3.3.2-3, and 4.3.2.1-1 to delete the reactor core isolation cooling (RCIC) system isolation on high RCIC room differential temperature.
In the cu rent design for Perry, isolation actuation instrumentation is installed to isolate RCIC if a steam leak develops.in the RCIC piping.
Diverse and redundant means of detecting a leak are included in the design.
The proposed change is intended to improve the reliability of the RCIC system by reducing the chances of an inadvertent and unnecessary isolation of RCIC on a spurious RCIC room high differential temperature signal.
2.0 EALUATION The leak detection system at Perry is designed such that a leak from RCIC that occurs in the RCIC equipment room may be detected by RCIC equipment room high temperature, RCIC equipment room high differential temperature, RCIC steam line high flow, RCIC steam line low pressure, or RHR/RCIC steam line high fl ow. The room differential temperature is measured by comparing the air temperature in the room with the air temperature in the associated room cooler downstream of the cooling coils in the room cooler.
The temperature of the cooling water for the coils in the room cooler varies with the temperature of Lake Erie, the ultimate low temperature heat sink for the cooling water The variations in the cooling water temperature lead to variations in system.
the measured differential temperature for the room even when the heat source in the room is constant.
In addition, the room cooler only operates when RCIC is operating. When the room cooler is started, the initial differential temperature tends to be larger than the steady state differential temperature.
These factors can combine to cause an inadvertent and unnecessary isolation of RCIC because of a sensed RCIC room high differential temperature when there is not a steam leak.
The licensee submitted the proposed change to TS 3.3.2 following an inadvertent isolation of RCIC on RCIC equipment room high differential temperature.
In this case there was no steam leak.
The isolation occurred Y YY O
P
. because of a sensed high differential temperature during a period when the temperature of Lake Erie was low.
RCIC was operating to supply inventory to the reactor vessel following a reactor scram due to a loss of feedwater.
After approximately 37 minutes of operation RCIC isolated when the sensed room differential temperature reached the established setpoint of 36 *F.
Testing by the licensee indicated that, although other factors contributed to this trip, the existing design impact.J the reliability of RCIC negatively.
The proposed change would remove the RCIC isolation on RCIC equipment room high differential temperature but leave the alarm function in place to provide the operators with information concerning potential leaks in the room. As an interim measure, the staff approved changes to the setpoint for the isolation of RCIC on RCIC equipment room high differential temperature (amendment nos. 26 and 28).
The setpoint changes provided greater margin between the operating differential temperature and the isolation setpoint.
Part 50 of Title 10 of the Code of Federal Regulations (10 CFR 50), Appendix A, General Design Criterion (GDC) 54, Piping Systems Penetratino Dateinment, states in part:
Piping systems penetrating primary reactor containment shall be provided with leak detection, isolation, and containment capabilities having redundancy, reliability, and performance capabilities which reflect the importance to safety of isolating these piping systems.
If the RCIC isolation on RCIC equipment room high differential temperature were removed, there would still be redundant, diverse, reliable means of isolating a leak from RCIC in the equipment room.
The remaining isolation functions would be RCIC equipment room high temperature, RCIC steam line high flow, RCIC steam line low pressure, and RHR/RCIC steam line high flow.
Therefore, GDC 54 would still be met.
The change would also increase the reliability of RCIC by eliminating the potential for unnecessary isolations of RCIC due to high RCIC equipment room high differential temperature caused by conditions other than a leak from RCIC.
Therefore, the proposed change to TS 3.3.2 is acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Ohio State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
Pursuant to 10 CF'R 51.21, 51.32, and 51.35, an environmental assessment and finding of no significant impact has been prepared and published in the Fedetal Reaister on December 16, 1993 (58 FR 65737).
Accordingly, based upon the environmental assessment, the Commission has determined that the issuance of this amendment will not have a significant effect on the quality of the human environment.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: Andrew J. Kugler Date:
April 28, 1994 4
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