ML20116N183
| ML20116N183 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 10/16/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20116N161 | List: |
| References | |
| NUDOCS 9211230224 | |
| Download: ML20116N183 (3) | |
Text
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g UNITED STATES
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NUCLEAR REGULATORY COMMISSION i
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wAsHINoToN, D C. 30586
-SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIFji 9
RELATED TO AMENDMENT NO.
66-TO FACILITY OPERATING LICENSE' E NPF-62
.ILLIN0IS POWER COMPANY. ET AL.
CLINTON POWER STATION. UNIT NO. 1 DOCKET NO. 50-461
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1.0 INTRODUCTION
By letter dated July 1, 1991, Flinois Power Compnay (IP)_ proposed changes to Clinton Power Station (CPS) Te.nnical Specifications.(TS)._ The changes are in the instrument setpoints (SP) and allowable values (AV) for vario_us "Contain--
ment and Reactor Vessel Isolation Control Systems" (CRVICS) trip functions.
These trip functions perform primary and secondary containment isolation (Cl),
4 main steam line isolation (MSLI), reactor water cleanup system isolation,
(RWCI), reactor core isolation cooling system isolation (RCICl)t, and residual heat removal system isolation (RHRI).
The existing trip setpoints and allowable values of the instruments in the Architect Engineer's (Sargent and a
Lundy (S&L)) scope-of. design were calculated assuming a 6-month calibration-interval, whereas those in the Nuclear Steam Supply System vendor's (General Electric) scope of design were based on an 18-month calibration-interval. The CPS Technical Specification and Plant Calibration Procedures allow instrument calibration to be performed at 18-month intervals.
Consequently, the S&L~
design scope instrument setpoints and allowable values are recalculated considering an 18-month calibration interval. Additionally, due to the _
revised cooling water flow rates and more advanced, yet conservative modeling_
of the heat exchanger performance, the leak detection: temperature calculations-were revised. The results of these revised calculations ~ formed the basis ~ for-a subsequent revision to-the-leak-detection ins +ruments setpoint-calculations.
The new setpoints and/or -allowable values were 2alculated using 18-month calibration interval and revised leak detection _ temperature.
2.0 EVALUATION Except for one item, all of the CRVICS-instrumentation channels affected by--
the proposed changes are associated with the primary coolant leak detection s y s t em.-
The purpose of the leak detection system instrumentation-is to monitor leakage from the reactor coolant pressure boundary and initiate an alarm and/or an isolation function before the predetermined temperature limits-are exceeded. The CPS Updated Safety Analysis Report (USAR) identifies that these temperature instrument setpoints initiate the required safety function-when temperature rise:in the monitored creaDis due to;a 25-gpm equivalent steam leak, assuming the area ventilation system is operating as designed.
The leak detection system temperature monitors are located in equipment areas in the Auxiliary Building, main steam tunnel, and the Turbine Building. The 4
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licensee's revised calcul:1tions resulted in changes to setpoint values whit.h, for the most part, were in the conservative direction. Allowable value changes which were in the nonconservative direction were a result' of revised -
room temperature calculations for a 25-gpm leak (analytical limit for the instrument setpuint variation due to the instrument inaccuracy, calibration uncertainties, and drift allowance during the 18-ironth calibration interval).
IP confirmed that the proposed trip setpoint and the allowable values were established in accordance with the methodology of Regulatory Guide 1.105,
" Instrument Setpoints." The licensee also confirmed that in all cases, a 25-gpm equivalent steam leak will be isolated within the time specified in the CPS USAR.
The staff's review of the proposed changes to the setpoint and allowable values of CRVIC system instrumentation channels supports the licensee's justification for the proposed changes.
Each of the conservative changes in the instrument setpoint is made to avoid spurious initiation of the safety function during normal plant opera-tions (i.e., the setpoint is greater than the maximum expected ambient temperature in the monitored area).
Each of the nonconservative changes (increased trip setpoint and/or allowable value) is less than or equal to the conservatively calculated temperature rise due to a 25-gpm equivalent steam leak in the area where the ventilation system is in operation. The increased allowable values also ensure that the 25-gpm equivalent steam leak is isolated in sufficient time to avoid adverse effects on the qualification of the safe-shutdown components in the respective areas.
The only instrument in the proposed changes that is not associated with the primary coolant heat detection system is the containment pressure monitor which initiates primary and secondary containment isolation for high containment pressure.
This change in the instrument trip setpoint is in a conservative direction (i.e., less than the existing setpoint value of the pressure transmitter). The proposed change is conservative and the trip setpoint is well above the design containment pressure during normal p' ant operating conditions so as to avoid spurious initiation of the safety functions during plant operation.
Based on the above evaluation, the staff concludes that the proposed changes to the setpoint and/or allowable values of CRVICS instrumentation are acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the appropriate Illinois State official w n notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
This amendment changes a requirement with respect do installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement. The staff has determined that
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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 Commission has previously issued a proposed finding that the amend-ment involves no significant hazards consideration and there has been no public comment on such finding (56 FR 37584). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be preoared in connection with the issuance of the amendment.
5.0 LONCLUSION 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 the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
- 1. Ahmed Date: Octooer 16, 1992 i