ML20033A260
| ML20033A260 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 11/13/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20033A259 | List: |
| References | |
| TAC-47092, NUDOCS 8111250044 | |
| Download: ML20033A260 (3) | |
Text
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S UNITED STATES g$egi NUCLEAR REGULA'ORY COMMISSION
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.%u SAFETY EVALUATICN BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPCRTING AMENDMENT NO. 87 TO FACILITY OPERATING LICENSE NO. OPR-57 GEORGIA POWER CCMPANY OGLETHORPE PCWER COR? ORATION MUNICIPAL ELECTRIC AUTHORITY OF GEORGIA CITY OF DALTON, GECRGIA ECWIN I. HATCH NUCLEAR PLANT, UNIT NO. 1 DOCKET NO. 50-321 Introducti:n 3y letter dated October 27, 1931, Georgia Power Company (GPC or the licensee) made application to modify the Technical Specifications (TSs) for the Edwin I. Hatch Nuclear Plant, Unit No.1 (Hatch 1), to accommodate 155 new fuel assemolies to be ased to replace leaking fuel assemblies. The c:re had previousi; been reloaded with 168 fuel assemblies for Cycle 5 in June 1951. While only 11 of the 158 fuel assemblies were determined, by 'nsrection, :: contain leaking fuel cins, the licensee took crudent action in re lacing ne entire 163 assemolies. This acticr is no: a j
rei:ac, :ut is nee:ed because the replacement fuel will be a:erated with Maximum Average Planar Linear Heat Generation Rate (MAPLHGR) values and
'4inimum Critical cwer Ratio (MCPR) values different from the 163 assemblies :cntaining the leaking fuel cins. The safety limit MCPR remains unchangec at 1.07.
Evaluation l
"A:LHSR Limit TS Curves The licensee's pro;osed MAPLHGR limits for the replacement fuel have been calculated using ;reviously ap roved methods presented in the General Electric C ::any (GE) letter of May 23,1C81, entitled, " Additional Information Regarding Extension of Emergency Core Cooling System Performance Limits." We conclude that these revised TS curves are acceptable.
i 0:eratine Limit MC?R Values t
t GPC recuested a T5 change for Hatch 1 for the Rod Block Monitor (REM) setpoint to 107 percent and the MCPR limit for all fuel tyce to 1.29.
The limit values are based on the rod withdrawal event (RWE).
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8111250044 811113 PDR ADOCK 05000321 P
. By letter dated May 18, 1981, GE presented a planned change in the method of analysis of the RWE for reloads. The change eliminates the specific calculation for a given reload of the peak Linear Heat Generation Rate (LHGR) for the event and uses a statistically detemined function (of R5M setting) for the change in critical power ratio relative to the initial ratio (aCPR/ICPR) for the event. The first use of this approach is for the Hatch 1 operation to replace fuel assemblies in Cycle 5.
The GE planned change in RWE analysis is similar to the change in analysis for the fuel mislocation event submitted by GE in November 1980.
Instead of a specific analysis for each reactor and cycle, a statistical analysis of the results of many such analyses was done to demonstrate a suitable bound which could be used for the event. The analysis showed that at a 95 percent probability level, 95 percent confidence level (95/95) the worst event MCPR would be greater than 1.03.
Our review cencluded that the analysis provided "a basis for discontinuir.g plant-cycle specific mislocated bundle analyses on present and near term supciemental reload licensing submittals," although the review continued with questions related to future populations of reloads.
For the RWE, GE has comoiled the results of 40 recent RWE analvses. The peak KW/FT of limiting bundles was compared to plastic strain limits arid the ratios were well under one at the 95/95 level. They thus concluded that, as for the fuel misloading event, the calculation and reporting of KW/:T values fcr each plant cycle is unnecessary. The same RWE analyses were also examined to determine the mean value anc standard deviation of 1.CPR/IC R as a function of the REM setting.
From this was developed a relation between the setting and a 95/95 value of aCPR/ICPR.
GE proposes tc use Inis relation as applied to :ne MCPR as determined either from the RWE or whatever other event maj provide the limiting value.
(If RWE is tiniting, a full RWE may be done to lower the MCPR, if desired.) Thus, enerz ily (95 percent of tne time at a 95 percent confidence) a given cycle will for MCPR from the RWE) which is greater than that from a be assigned a aCPR cycle s:eci ic analysis.
The review of tr.is proposal has reached a conclusion similar to that for the fuel misiccation event.
It is reasonable to base a reload analysis for the event on s statistical analysis of past reloads. A 95/95 level for the RWE limited initial MCPR, which implies a 95/95 level for not exceeding the corewide event MCPR (e.g.1.07) is a reasonable level, com:atible with other limits used by the NRC staff. The analysis presented Drovides sufficient information and a basis for discontinuing plant-cycle s eci fic RWE analyses on present and near term supplemental reload licensing submittals, although the review will c:ntinue to examine future populations of reloads.
For the Dresent Hatch 1 replacement fuel, the information is sufficient to conclude that the MCPR value of 1.29 for all fuel types when using a REM setting of 107, band on the statistical analyses of RWE, is sufficient to provide a suitable limit without the need for a cycle specific analysis and is thus acceptacle.
1 1 Environmental Consideration We have determined that the amendment does not authorize a change in effluent ' types'or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action whicn is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(a), that an environmental in:act statement, or negative declaration and environ-mental impact a:praisal need not be prepared in connection with the issuance of this amendment.
Conclusien We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the Orebability or consequences of accidents previously considered and d:es not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the precosed manner, and (3) such activities will be conducted in compliance with the C enission's regulations and the issuance of this amendment will not be inimical t0 tne commen defense and security er to the health and safety of the ;ublic.
Catec:
Novenber 13, 1981
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