ML20133L443
| ML20133L443 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 08/06/1985 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20133L427 | List: |
| References | |
| NUDOCS 8508120615 | |
| Download: ML20133L443 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION r,
j WASHWGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION
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-SUPPORTING AMENDMENT NO. 89 TO FACILITY LICENSE NO.-DPR-71 AND AMENDMENT NO. 114 TO FACILITY LICENSE NO. DPR-62 CAROLINA POWER & LIGHT COMPANY BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 DOCKET NOS. 50-325 AND 50-324
1.0 INTRODUCTION
.By letter dated April 9,1985, the Carolina Power & Light Company (the licensee) submitted proposed changes to the Technical Specifications (TS) appended to Facility Operating License Nos. DPR-71 and DPR-62 for the Brunswick Steam Electric Plant, Units 1 and 2.
The proposed changes would change the TS to pennit loading of up to four fuel bundles around the source range monitor (SRM), if needed, in order to obtain the required minimum count. The changes are directed at the Limiting Conditions for Operation (LCO) for core monitoring during core alterations, and addresses source range monitor operability, via count rate, and fuel assembly loading limits.
It specifically involves Specification 3.4.9.2 and related Bases and Definitions for both Units 1 and 2.
2.0 BACKGROUND
The Brunswick units, in comon with many other boiling water reactors (BWRs), use spiral unloading and reloading for full core reloading. The.
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spirals for reloading begin at the core center and^ grow outward. The initial fuel loaded is thus some distance from the SRMs which are located nearly halfway out along the core radius.
For such operations it is
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generally required that at least a minimum count rate be maintained on the SRMs whenever fuel is in the core. This minimum count rate for Brunswick is 3 counts per second.(cps). There are exceptions to this requirement, however. The exception relevant to the present request is that-during I
spiral reloading including (at least some) irradiated fuel, a given maximum number of fuel assemblies may be loaded around each SRM before requiring i
the 3 cps operability state. The concept is that the neutrons produced by irradiated fuel (e.g., by gama-neutron reactions on the D,0 in the water) l can provide the.needed SRM count rate to demonstrate the required operability while still maintaining a highly subcritical fuel array.
The present Brunswick TS permit a maximum of two assemblies to be loaded i
adjacent to each SRM before requiring 3 cps. The requested change is to l
allow up to four.
If some of the fuel to be loa'ded at these locations were i
fresh, irradiated assemblies would be substituted until core load was complete, at which time it would be exchanged for the fuel intended for
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that location. The irradiated fuel thus used would be selected for high irradiation and to have a lower reactivity worth than the fuel it is
, temporarily replacing.
3.0 EVALUATION Durin'g the past several years several utilities have requested Technical Specification changes to permit loading up to four assemblies adjacent to each SRM before attaining required count rates to demonstrate operability.
The primary basis for acceptability is that the resulting configurations are far subcritical. This applies to the presently allowed Brunswick configuration, two assemblies adjacent to each SRM, or the configurations, up to four, accepted for other reactors. Generally at least eight tightly clustered assemblies, without control rods, are required for criticality.
In the requested configurations tnere will be at most only four tightly i
r clustered assemblies at each SRM, which will be neutronically well isolated (no reactivity interaction) from those around other SRMs and control rods will be inserted. Thus the system will be far suberitical when the initial (SRM) loading is completed and the SRM meet the required count rate ~.
Therefore, this is acceptable for Brunswick.
The proposed changes to the Technical Specifications for both Brunswick Units 1 and 2 are:
(1) to the Definitions for S iral Reload and Spiral Unload to include up to four (rather than two assemblies around each SRM.
(2) to Specification 3.9.2 and 4.9.2, Refueling Operations.
Instrumentation, to pemit four (rather than two) assemblies to be loaded around each SRM in order to achieve 3 cps, before requiring that count rate.
(There is also an administrative word change of
" Condition" to Operational Condition.")
f (3) to the Bases for 3/4.9.2 to indicate four (rather than two) assemblies.
(4) to the Bases for 3/4.1.1, Shutdown Margin, indicating that deviations from the nomally scheduled loading patterns are permitted to allow irradiated fuel not scheduled to be located around the SRMs to be temporarily loaded to achieve required SRM count rate if the (cold) reactivities of the loaded assemblies are, individually, less than the l
assemblies scheduled for the location. Thus the shutdown margin analysis for the scheduled pattern bounds the altered pattern.
I Since the only proposed changes are to increase the number of assemblies l
around each SRM from two to four and to permit the use of irradiated fuel l
at the four locations, these Technical Specifications changes suitably l
cover the proposal and are acceptable.
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Carolina Power & Light Company has requested TS changes for Brunswick, Units 1 and 2 to increase from two to four the number of irradiated fuel assemblies which may be located around SRMs before requiring 3 cps. The primary reason for the request is to provide greater assurance that the required count rate can be achieved. The primary basis for the safety of the requested change is that the core will be subcritical during the loading around the SRMs, and subsequent loading will be well monitored by the SRM.
Based on our review we have concluded that the core will be subcritical during the loading around SRMs and subsequent loading will be well monitored by the SRMs. Therefore, this process is acceptable, the requested Technical Specification changes appropriately implement the process and the changes are also acceptable.
4.0 ENVIRONMENTAL CONSIDERATION
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The amendments involve a change in the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. The 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 consideration and there has been no public comment on such finding.
Accordingly, the amendments meet the eligibility criteria for categorical exclusionsetforthin10CFR51.22(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 amendments.
5.0 CONCLUSION
We have 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, and (2) such activities will be conducted in compliance with the Commission's regulations and 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:
H. Richings
. Dated: August 6,1985 e
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