ML20073D942
| ML20073D942 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/22/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20073D937 | List: |
| References | |
| NUDOCS 9409280159 | |
| Download: ML20073D942 (3) | |
Text
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[pa arogk UNITED STATES y.-
NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 20555 o001
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SAFETY EVALVATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 95 TO FACILITY OPERATING LICENSE NO. NPF-49 NORTHEAST NUCLEAR ENERGY COMPANY. ET AL.
MILLSTONE NVCLEAR POWER STATION. UNIT NO. 3 DOCKET N0. 50-423
1.0 INTRODUCTION
By letter dated April 18, 1994, the Northeast Nuclear Energy Company, (the licensee) submitted a request for changes to the Millstone Nuclear Power Station, Unit No. 3 Technical Specifications (TS). The requested changes would revise Surveillance Requirement (SR) 4.7.14 to verify area temperature limits at least once per 7 days when the Electrical Environmentally Qualified (EEQ) temperature monitor (datalogger) alarm is operable, and at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> when the datalogger alarm is inoperable.
The primary purpose of area temperature monitoring is to display area temperature associated with the Limiting Condition for Operation (LCO). The area temperature limitations ensure that safety-related equipment will not be subjected to temperatures in excess of their environmental qualification temperatures.
Exposure to excessive temperatures may degrade equipment and can cause a loss of its operability. The temperature limits include an allowance for instrument error of f2.2 F.
This information provides the necessary support for the operator to take the manual actions for which no automatic control is provided and that are required for safety systems to accomplish their safety functions for Design Basis Accidents (DBAs).
The temperature limits are used to establish the environmental qualification operating envelope for various area of the plant (e.g., containment, diesel generater building, turbine building, and main steam valve building). The maximum peak air temperatures were calculated to exceed the design temperature for only a few seconds during transients. The temperature limit is also used in the depressurization analyses to ensure that the minimum pressure limit is maintained following an inadvertent actuation of the Containment Spray System.
The basis of a design temperature, however, is to ensure the performance of safety related equipment inside each particular area.
Thermal analyses showed that the time interval during which the ambient temperature exceeded the design temperature was short enough that the equipment surface temperatures remained below the design temperature.
Therefore, it is concluded that the calculated transient air temperatures are acceptable for DBAs.
9409280159 940922 DR ADOCK 050004 3
The operability of the EEQ datalogger alarm function ensures that there is sufficient information available on selected area temperatures to monitor and to assess the area status and behavior following an accident.
The availability of the datalogger alarm is important so that responses to corrective actions can be observed and the need for, and magnitude of, further actions can be determined.
2.0 EVALUATION Control room operators use a personal computer (PC) te retrieve information from a data acquisition system to determine that area temperatures are within their limits.
If communication with the data acquisition system is lost, an alarm condition is received during the data transmission and an error message is displayed.
If a system malfunction arises, the alarms would be monitored to verify that area temperature limits are not exceeded once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> as the current TS requires.
The proposed amendment would change the current SR frequency to also determine that area temperatures are within their limits at least once per 7 days when the EEQ datalogger alarm function is operable.
The frequency is based on operating experience that demonstrates that the failure of the data acquisition system is rare, and that systems are in place to alert the operator of any failures and/or errors. The surveillance must be performed within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> each time the datalogger alarm function is inoperable. Thus, performance of the surveillance ensures that undetected overt temperature excursions are limited to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The amendment request includes the licensee's commitment to revise surveillance procedures to require that the PC monitor be checked for error messages during every shift. The licensee contends that a temperature excursion can be detected by the datalogger alarm function before the current surveillance because the area monitoring system is a continuous on-line data acquisition system. Therefore, the temperature data is available regardless of the surveillance frequency and/or datalogger alarm operability.
The staff has reviewed the changes to SR 4.7.14 and found that they are acceptable because (1) the qualification for a design basis event is not affected, (2) the determination of area temperatures associated with the LC0 required area temperature limits is maintained, and (3) the surveillance procedures will require that the PC monitor will be checked for any error messages once per shift.
3.0 STATE CONSULTATIQH In accordance with the Commission's regulations, the Connecticut State official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a surveillance requirement.
The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Comission has previously issued a proposed finding that the amendment involves no significant hazards
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. consideration, and there has been no public. comment on such finding (59 FR 39593). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR i
51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, l
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 the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
Maudette Griggs Date:
September 22, 1994 i
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