ML17348B067
| ML17348B067 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 08/26/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17348B066 | List: |
| References | |
| NUDOCS 9109050312 | |
| Download: ML17348B067 (3) | |
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~O 4~**4 UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO 148 TO FACILITY OPERATING LICENSE NO.
DPR-31 AND AMENDMENT NO. 143 TO FACILITY OPERATING LICENSE NO. DPR-41 FLORIDA POWER AND LIGHT COMPANY TURKEY POINT UNIT NOS.
3 AND 4 DOCKET NOS. 50-250 AND 50-251
- 1. 0 INTRODUCTION By letter dated June 21, 1991, Florida Power and Light Company (the licensee) requested approval of amendments to the Technical Specifications (TS) of the Turkey Point Plant Units 3 and 4.
Specifically, the proposed amendments would revise Technical Specification 4.7.2.b to allow heatup to 547'F prior to conducting component cooling water (CCW) heat exchanger performance tests, while still requiring performance of the test prior to entering mode 2.
2.0 DISCUSSION Turkey Point monitors intake cooling water
( ICW) temperatures and CCW heat exchanger-performance to assure that adequate heat removal capability is maintained.
CCW heat exchanger performance tests are accomplished by measuring a temperature differential across each CCW heat exchanger for both ICW and CCW.
Heat exchanger fouling and allowable ICW temperatures are then calculated using the differential temperatures (delta-T) and ICW flow rates.
When the Reactor Coolant System (RCS) average temperature is at least 547'F, the heat load on the heat exchangers is adequate to provide significant delta-Ts, such that the calculation is reasonably accurate.
With RCS temperatures less than 200'F, the heat load, and therefore the delta-Ts, are small.
The ICW delta-T under these conditions is approximately 0.3'F.
Therefore, the magnitude of the potential measurement errors approaches the actual delta-T values, resulting in unreliable calculations.
The current surveillance requirement is.applicable to modes 1, 2, 3, and 4.
The licensee proposes to conduct this surveillance only after plant heatup to at least 547'F, but prior to entering mode 2.
In order to assure CCW operability and satisfactory heat exchanger performance prior to entering mode 4, the licensee will clean the CCW heat exchangers prior to mode 4 operation when TS 4.7.2.b would otherwise prohibit entry into mode 4 (i.e.,
when greater than 31 days have elapsed since the heat exchanger performance test was satisfactorily accomplished).
In addition, CCW operabi lity will be confirmed in accordance with TS 4.7.2.a prior to entry into mode 4.
By performing the heat exchanger performance tests under hot plant conditions and prior to entry i
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into mode 2, the licensee proposes to confirm CCW operability and satisfactory heat exchanger performance prior to reactor criticality.
3.0 EVALUATION The operability of the CCW system ensures that sufficient cooling capacity is available for continued operation of safety-related equipment during normal and accident conditions.
Under the current TS 4.7.2.b, the heat exchanger performance test is required prior to entry into mode 4, and at least once every 31 days thereafter while in modes 1, 2, 3, or 4.
Conduct of this test prior to mode 4 operation is unreliable due to small (near zero) delta-Ts across the heat exchangers.
These small delta-Ts result from the low RCS system temperature and reduced heat loads, and they magnify the inherent instrument errors.
In the worst case, these errors could cause indication of satisfactory heat exchanger performance when heat exchanger performance is, in fact, unsatisfactorily degraded.
As a result, the plant could be heated up and the reactor taken critical with insufficient component cooling.
By increasing the RCS temperature prior to conduct of the heat exchanger performance test of TS 4.7.2.b(2),
greater heat loads are placed on the heat exchangers, resulting in larger delta-Ts.
This, in turn, minimizes the effect of instrument errors on the calculations of heat exchanger performance.
The test then provides greater assurance of heat exchanger operability, and the corresponding ability of the CCW system to cool safety-related components during normal and accident conditions.
Assurance of satisfactory heat exchanger performance is thus deferred until the RCS temperature is at least 547'F.
Additionally, the licensee has committed to cleaning the heat exchangers prior to mode 4 operations, when more than 31 days have elapsed since the heat exchanger performance was verified in accordance with TS 4.7.2.b(2).
In conclusion, CCW system operability will be demonstrated prior to mode 4
operation in accordance with TS 4.7.2.a, and heat exchanger performance will be demonstrated by conduct of the performance test of TS 4.7.2.b(2) prior to mode 2 operation if not performed during the previous 31 days.
The staff accepts this means of demonstrating CCW system operability during plant heatup.
4.0 STATE CONSULTATION
Based upon the written notice of the proposed amendments, the Florida State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
These amendments change a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements.
The NRC staff has determined that the amendments involve 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 amendments involve no significant hazards considera-tion and there has been no public comment on such finding (56 FR 33957).
Accordingly, these amendments meet 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 prepared in connection with the issuance of these amendments.
6.0 CONCLUSION
The Commission 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 amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
D.
Dorman Date: August 26, 1991