ML20217K613
| ML20217K613 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 04/27/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20217K604 | List: |
| References | |
| NUDOCS 9805040039 | |
| Download: ML20217K613 (3) | |
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UNITED STATES g
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NUCLEAR REGULATORY COMMISSION g
WASHINGTON, D.C. someH001
- .l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMFNDMENT NO 193 TO FACILITY OPERATING LICENSE NO. DPR-71 AND AMENDMENT NO. ??a TO FACILITY OPERATING LICENSE NO. DPR-82 CAROLINA POWER & LIGHT COMPANY BRUNSWICK STEAM Ft FCTRIC PLANT. UNITS 1 AND 2 i
DOCKET NOS. 50-325 AND 50-324 i
1.0 INTRODUCTION
in its letter of October 29,1997, supplemented by letters dated January 28 and April 20,1998, Carolina Power & Light Company (CP&L), the licensee for Brunswick Steam Electric Plant (BSEP) Units 1 & 2, submitted proposed changes to the Technical Specifications (TS ). The changes would update the TS description of control rod assemblies to allow for boron carbide and hafnium absorber materials. The revised TS section is consistent with NUREG-1433,
" Standard Technical Specifications." The licensee has also restricted the use of control rod assembly absorber materials to those approved by the NRC staff.
2.0 DISCUSSION AND EVALUATION i
TS 5.3.2, Control Rod Assemblies, provides a description of the control rod assemblies in the i
reactor core. The proposed TS change is being requested to support the replacement of a portion of the BSEP-1 control rod assemblies with a different design than currently used. The control rods currently installed in the BSEP reactors were designed and fabricated by General Electric (GE). Three distinct types of GE control rod assemblies are currently used in BSEP-1&2. The original equipment type is a control rod assembly containing only boron carbide (B,C) absorber tubes. The second type is a hybrid control rod assembly which uses boron carbide absorber tubes and three solid hafnium rods in the outside edge of each wing. The third type is an advanced hybrid control rod assembly which uses a combination of boron carbide absorber tubes, solid hafnium strips as replacements for select boron carbide absorber tubes, and a hafnium absorber plate at the top of each cruciform wing.
During the next BSEP-1 refueling outage, CP&L is planning to install the model CR82M-1 control rod assembly manufactured by Asea Brown Boveri (ABB). By letter dated February 20, 1986, the staff accepted Licensing Topical Report (LTR) TR-UR-85-225, " ASEA-ATOM Control Blades for U.S. BWRs." One of the control rod assembly designs covered by LTR TR-UR 9905040039 980427 PDR ADOCK 05000324 P
. 225 is designated as " Type-4." The Model CR 82M-1 control rod assemblies di#er from the j
Type 4 design in three ways.
j The model ABB CR82M-1 assemblies use 316L stainless steel wing material, rather I
than 304L stainless steel. The use of 316L stainless steel will not s#ect any physical j
arrangement or orientation of any system. The change will provide equivalent or better physical properties, including increased resistance to cracking. This is acceptable to the NRC staff.
Cobalt content is reduced in the ABB Model CR 82M-1 compared to the Type 4 model.
This change provides a reduction in the gamma radiation source term, and is acceptable to the NRC staff.
The nuclear exposure life limit of a control rod assembly is defined as a 10 percent-reduction in cold rod worth, relative to the initial worth of an original equipment blade.
Control rod blade segment neutron exposure is tracked by the on-line core monitoring system (CMS) computer in terms of integrated neutron flux. By convention, the Integrated segment flux is expressed in units of 10" neutrons per square centimeter (snyt). The limiting lifetime (10% worth reduction) for the original GE control rod assemblies corresponded to approximately 2.5 snyt. The. nuclear exposure lifetime of the ABB CR82M-1 control rod assembly (10% worth reduction relative to the initial worth of the original GE assembly) c:orresponds to 5.1 snvt, as tracked by the CMS. This is due both to a higher initial B C loading, and the fact that the hafnium worth remains 4
relatively constant. Since the control rod worth limit is equivalent, this is acceptable to the NRC staff.
In addition, the revised TS section is consistent with NUREG-1433, " Standard Technical Specifications." The licensee has stated that shutdown margin is increased slightly with the Model CR 82M-1 assembly (a conservative change). The licensee is also required by the TS to use only previously approved control rod materials. Therefore, the changes are acceptable.
3.0 SIATE CONSULTATION in accordance with the Commission's regulations, the State of North Carolina official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
These 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. 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 consideration, and there has been no public comment on such finding (62 FR 66137). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR l
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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 amendments.
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 cperation 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: G.Golub, NRR/DSSA Date:
April 27, 1998 l
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AMENDMENT NO.193 TO FACILITY OPERATING LICENSE NO. DPR BRUNSWICK, 1
- UNIT 1 AND AMENDMENT NO. 224 TO FACILITY OPERATING LICENSE NO. DPR BRUNSWICK, UNIT 2 DISTRIBUTION DeelseWider PUBLIC PDil-1 Reading File J.' Zwolinski OGC G. Hill (4)
T. Collins ACRS OPA OC/LFDCB i
I L. Plisco, Rll l
i cc: Brunswick Service List I
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