ML20056H370
| ML20056H370 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 08/24/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20056H366 | List: |
| References | |
| NUDOCS 9309090204 | |
| Download: ML20056H370 (4) | |
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wAssiscTou, o.c. 20sss-oooi gv j SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 67 TO FACILITY OPERATING LICENSE NO. NPF-47 GULF STATES UTILITIES COMPANY RIVER BEND STATION. UNIT 1 DOCKET NO. 50-458
1.0 INTRODUCTION
By letter dated July 2,1993, Gulf States Utilities Company (GSU) (the licensee) requested an amendment to Facility Operating License No. NPF-47 for the River Bend Station, Unit 1.
The proposed amendment would revise Technical Specification (TS) 6.9.3.2 to incorporate a footnote that permits the licensee to disregard a.0a minimum critical power ratio (MCPR) penalty for misoriented fuel bundles for the remainder of the Cycle 5 fuel load.
TS 6.9.3.2 requires that the core operating limits be determined using methods described in the latest version of NEDE-240ll-P-A, " General Electric Standard Application for Reactor Fuel," (GESTAR) approved by the NRC.
GESTAR presents generic information relative to the fuel designs and analyses of General Electric boiling water reactor plants for which GE provides the fuel.
The generic information is supplemented by plant cycle-unique information and analytical results. GE documents and supplies this information to the licensee in the supplemental reload licensing report, including a listing of the fuel to <e loaded in the core and the results of the safety analyses.
1 GE performed a cycle specific analysis to calculate the operating limit minimum critical power ratio (0LMCPR) for River Bend for the Cycle 5 reload.
That analysis concluded that the misoriented fuel bundle event is the limiting event for determining the OLHCPR for Cycle 5 operation. The OLMCPR reported in the supplemental reload licensing report was 1.22.
In preparing the Core Operating Limits Report (COLR) required by TS 6.9.3.1, the licensee performed a 10 CFR 50.59 evaluation to justify disregarding the
.04 MCPR penalty f ir a misoriented fuel bundle and listed the OLMCPR for Cycle 5 operations in the COLR as 1.18.
The licensee based disregarding the penalty for a misoriented fuel bundle on the extensive verification of fuel bundle orientation that was performed during and after loading the core. The verification included independent review of video tapes of the fuel bundles in the core.
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However, disregarding the penalty for a misoriented fuel bundle resulted in the OLMCPR being calculated by a method not previously reviewed and approved by the NRC and therefore required a change to TS 6.9.3.2 prior to implementation.
In addition to the requested change, the staff is making an editorial clarification to TS 6.9.3.2.
The current version of TS 6.9.3.2 requires that the licensee use the analytical methods in the latest version of GESTAR approved by the NRC in determining the core operating limits. The intent of the requirement was that the licensee would use the revision that was approved at the time the reload analysis was performed. With this clarification, the change removes the possibility that the technical specification could be interpreted to require that the methods for determining the core operating limits be revised each time a new revision of GESTAR is approved.
2.0 EVALUATION The required OLMCPR at steady state operating conditions specified in the COLR is derived from the established fuel cladding integrity safety limit MCPR of 1.08 and 1.07 with either one or two recirculation loop (s) in operation, respectively, and an analysis of abnormal operational occurrences.
For any abnormal operating occurrence analysis, with the initial condition of the reactor being at the steady state operating limit, it is required that the resulting MCPR does not decrease below the safety limit MCPR at any time during the occurrence assuming instrument trip settings are correct.
To assure that the fuel cladding integrity safety limit is not exceeded during any anticipated abnormal operating occurrence, the most limiting events are
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analyzed to determine which result in the largest reduction in critical power ratio. The limiting event yields the largest delta MCPR. When added to the safety limit MCPR, the required minimum OLMCPR is obtained.
In addition to abnormal operating occurrences, the effect of a misoriented fuel bundle on OLMCPR is also analyzed in determining the limiting event.
The Cycle 5 reload core design was based on an OLMCPR of 1.18.
Subsequent to manufacturing and delivering the fuel for the r' Mad core, but prior to restart, GE discovered an error in the treatmen. ;,f misoriented fuel bundles in the analysis for the reload. GE subsequently performed a cycle specific analysis to calculate the OLMCPR for River Bend for the Cycle 5 reload. That analysis concluded that the misoriented fuel bundle event is the limiting event for determining the OLMCPR for Cycle 5 operation.
The OLMCPR reported by GE in the Cycle 5 supplemental reload licensing report is 1.22.
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Prior to startup out of the refueling outage, the licensee and GE met with the NRC to discuss a GE proposal to reclassify the misoriented fuel bundle from an r
abnormal operating occurrence (A00) to an accident. The licensee was informed that misoriented fuel bundles must be treated as an A00 until the NRC's review of the GE proposal was completed.
Because the core reload was designed for an OLMCPR of 1.18 and operating at an OLMCPR of 1.22 will result in reduced operating flexibility and possible derate of the facility, the licensee was s
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.- told that if they chose to submit a TS amendment request, the NRC would consider a one-time deviation from the OLHCPR penalty if the licensee could provide adequate justification.
The licensee performed a calculation to estimate the probability of operation with a misoriented fuel bundle given the extensive verification of fuel bundle orientation and location in the core that occurred following the last reload of the core. This calculation est.imated the probability of a misoriented fuel bundle to be 7.36E-07 per cycle.
In addition, a subsequent independent verification of fuel bundle orientation in the core was performed by GE through the review of video tapes of the core. To provi + additional assurance that the core was properly loaded, the NRC's Resident Inspector reviewed the video tapes of the core.
The editorial change revises the parenthetical language at the end of TS 6.9.3.2 from " latest approved revision" to "the approved revision at the time the reload analyses are performed." This change removes the possibility that the technical specification could be interpreted to require that the methods for determining the core operating limits be revised each time a new revision of GESTAR is approved. The licensee has agreed to the editorial change.
The staff has reviewed the licensee's submittal and has concluded that the probability of the existence of a misoriented fuel bundle is very low and that operating the plant with an OLMCPR of 1.18 will satisfy the licensing requirements for safe operation.
Based on our review, including the Resident Inspector's inspection of the core loading, we conclude that the proposed change is acceptable.
3.0 STATE CONSULTATION
In accordance with the Comission's regulations, the Louisiana State official was notified of the proposed issuance of the amendment. The State official had no coments, i
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a j
facility component located within the restricted area as defined in 10 CFR Part 20. 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 consideration, and there has been no public coment on such finding (58 FR 39257). 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 prepared in connection with the issuance of the amendnent.
5.0 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 amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
Edward T. Baker, PDIV-2/NRR Date: August 24, 1993 I
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