ML20214R530
| ML20214R530 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 12/01/1986 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20214R534 | List: |
| References | |
| NUDOCS 8612080010 | |
| Download: ML20214R530 (2) | |
Text
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- f" UNITED STATES NUCLEAR REGULATORY COMMISSION n
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SAFETY EVALUATICU BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT N0. 65 TO FACILITY OPERATING LICENSE NPF-9 AND APENDVENT NO. 4 6 TO FACILITY OPERATING LICENSE NPF-17 DUKE POWER COMPANY DOCKET NOS. 50-369 AND 50-370 McGUIRE NUCLEAR STATION, UNITS 1 AND 2 INTRODUCTION By letter dated December 12, 1985, Duke Power Company, the licensee for McGuire Nuclear Station, Units 1 and 2, requested a change to Technical Specification (TS) surveillance requirement 4.2.5 and its referenced Table 3.2-1 "DNB (departure from nucleate boiling) parameters" for the Peactor Coolant System average temperature (Tavg) and the pressurizer pressure asso-ciated with station instrumentation. The existing TS specifying limits for these DNB related parameters does not account for indication instrumentation measurement uncertainties and therefore requires that the measured values, as given by station indication instrumentation, be adjusted for instrument-ation uncertainties prior to comparison with the proposed parameter limits of TS Table 3.2-1.
The requested amendments would adjust these parameters to include the instrumentation uncertainties, allowing direct comparison against measured values, as indicated on station instrumentation. Associated TS Bases 3/4.2.5 "DNB Parameters" would also be revised to reflect the pro-posed changes to TS 4.2.5 and Table 3.2-1.
These changes for pressurizer pressure limit in Table 3.2-1 would also cor-rect typographical errors in the existing value and unit (existing value
"> 2230 psai"should have been "> 2220 psia" based upon the values assumed iii the FSAR safety analyses) an'd would express this limit in units of psig rather than psia.
The requested changes to Table 3.2-1 would delete all entries regarding three-loop operation.
(Such limits had been left blank and were irtended for future amendments pending NRC approval of three-loop operation.)
EVALUATION McGuire Technical Specification 3.2.5, Limiting Condition for Operation for DhD Parameters, requires that the Reactor Coolant System average temperature i
and pressurizer pressure be maintained within the limits specified in Table 3.2-1.
Associated surveillance specification 4.2.5 requires that these temp-erature and pressure parameters in Table 3.2-1 be periodically verified to be within their specified limit.
Table 3.2-1 specified that the coolant average temperature should be no higher than 593"F and the pressurizer pres-sure should be no lower than "??30 psai".
8612090010 861201 PDR ADOCK 05000369 P
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o The staff finds that the safety analyses for l'cGuire were based upon a pres-surizer pressure limit no lower then 2220 psia. Therefore, the value in Table 3.2-1 prior to these amendments, 2230 psia. ves overly conservative and re-sulted from a typograchical error. This error is corrected in the present amendments in that the changes for pressurizer pressure (discussed below) are based upon the intended value, 2220 psia. The reviseo pressurizer pressure limits are also specified in units of psig, rather than psia, because steticn indication instrumentation is in psig.
The revision to Table 3.2-1 by these amendments substitutes new values for the
" Reactor Coolant System Tavg" and " Indicated Pressurizer Pressure" respectively.
Values are given in the revised table for indication by instrument meters or corputer readout available to the staticn cperators. The limits in the revised table are adjusted by appropriate uncertainties in the indicating system so that the limits previously in the Technical Specifications (as corrected for the error in pressurizer pressure) are maintained. fccordinoly, surveillance specification 4.2.5 is chanced to require that these parameters in Table 3.2-1 be periodically measured by averaging the indications (meter or computer) of the operable channels and verified to be within the reviseo specified limits.
Associated Bases 3/4.2.5, "DNB Parameters," is supplementea to note that (1) the " indicated Tavg values and the indicated pressurizer pressure values correspcod to analytical limits of 592.6*F and 2220 psia respectively, with allcwance for indication instrumentation measurement uncertainty", erd that (2) "the indication instrumentation measurement uncertainties are eccounted for in the limits provided in Table 3.2-1."
The revised Table 3.2-1 differentiates between limits for the case of four operable channels and the case of three operable channels. This is appro-priate because carameter uncertainty associated with the average of four independent channels is different than that for the average of three inde-perdent channels. Similarly, the revised table differentiates between limits for indications provided by analog meters and those provided by digital com-puters because channel accuracy associated with these two information sources differs.
He find that the uncertainty allowances centained in the licensee's letter of Decenber 12, 1985, and used for the revised linits, are appropriate. Since conformance with the previcus Specification requires that the same station indication instrunentation in the new Specificatier t'c adjusted for instru-mentation uncertainties prior to comparison with the specified limits, the Change is essentially acministrative, and does not Chance thF safety Of tl:e statice.
Pe therefor <- find the revised limits as discussed, including tic estociated wording changes and revised Casis in the licensee's submittt!,
ecceotable.
Prior to these amendments Table 3.2-1 had included provisions for limits during operation with three reactor coolant loops in operaticn. flo actual values had been specified; rather, this portion of the table had been intended for future application pendfre lictrsee analyses and NRC approval of such operation.
In accordance with the licensee's request, the present amendnints delete these provisions for including possible future three-loop operation values. The revised Table 3.2-1, therefore, applies only for four-loop oper-ation. Delction of such provisions does not affect safety and is purely administrative; this change is, therefore, ecceptable.