ML20205P517
| ML20205P517 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 04/09/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20205P510 | List: |
| References | |
| NUDOCS 9904200198 | |
| Download: ML20205P517 (4) | |
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[t UNITED STATES l
j NUCLEAR REGULA'iORY COMMISSION
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't WASHINGTON, D.C. 20555 4 001
.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.142 TO FACILITY OPERATING LICENSE NO. NPF-12 SOUTH CAF JLINA ELECTRIC & GAS COMPANY SOUTH CAROLINA PUBLIC SERVICE AUTHORITY VIRGIL C. SUMMER NUCLEAR STATION. UNIT NO.1 DOCKET NO. 50 395
1.0 INTRODUCTION
By letter dated September 18,1998, as supplernented by letter dated February 5,1999, South i
Carolina Electric & Gas Company (SCE&G) requested Technical Specifications (TS) changes to the Virgil C. Summer Nuclear Station (VCSNS) to incorporate a new reactor core power distribution monitoring system (PDMS). The new system uses an NRC-approved Westinghouse proprietary computer system, the best estimate analyzer for core operation-nuclear (BEACON),
to augment the flux mapping system when performing a core power distribution curveillance.
The proposed TS changes allow the use of the PDMS at power ranges greater than 25% rated thermal power (RTP). At ranges less than or equal to 25% RTP, the licensee must declare the PDMS inoperable. The existing TS will continue to require the licensee to perform a surveillance using the present movable incore detector system when the PDMS is declared inoperable.
The February 5,1999, submittal contained clarifying information only and did not change the initial no significant hazards consideration determination.
2.0 EVALUATION in a submittal dated September 18,1998, SCE&G propmed changing the current VCSNS TS associated with the BEACON monitoring system as follows:
change Limiting Condition for Operations (LCO) 3.1.3 and 3.2.2 to show when to use the PDMS or when to use the movable incore detectors to obtain power distribution information change LCO 3.2.3 to 1) show when to use the PDMS or when to use the movable incore detectors to obtain power distribution information, and 2) to properly consider measurement uncertai,ity when determining FN cH change Surveillance Requirements (SR) 4.2.2
- show using the PDMS above 25% RTP to obtain rower distribution information, rather than using the movable incore detectors 9904200198 990409 PDR ADOCK G5000395 P
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j l specify using the movable incore detectors to obtain power distribution information when the PDMS is inoperable i
- properly incorporate measured Fa(z) manufacturing and measurement i
uncertainties l
change several TS to replace "incore mapping," "incore flux mapping," " power
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distribution map "
- full core flux map," " flux map" or " flux mapping," with " core power distribution measurement (s)"
l make editorial changes to LCO 3.3.3.2 and SR 4.3.3.2 deleting incorrect references to
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F,,, since all reference to F,, should have been deleted as part of the Amendment 75 TS change associated with Vantage 5 Fuel
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change LCO 3.3.3 to add PDMS TS
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update TS Bases sections 3/4.2 and 3/4.3 to discuss the uncertainties used for the
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measurements obtained using the PDMS and to add the bases for the new PDMS operability requirements 1
update Administrative Controls Section 6.9.1
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- add Fa(z) and FN.sH manufacturing / measurement uncertainties to the cort operating limits report (COLR) add WCAP-12472-P-A to document the analytical methods used to determine the core operating limits
- correct editorial errors in the COLR, the licensee added the definitions and the equations which the PDMS or the flux mapping system use to determine the applicable measurement uncertainties associated with the core peaking factors. The constants placed in the COLR are used as coefficients in the uncertainties calculations and are determined using NRC-approved methodology. These constants are typically revised periodically to reflect cycle-specific requirements.
The NRC-approved BEACON Topical Report WCAP 12472-P-A (Ref.1) is acceptable for use at VCSNS, and it describes a greatly improved on-line power distribution monitoring system. This system provides direct, continuous core power distribution determination and directly relates power distribution to fuel safety limits for Westinghouse plants. At VCSNS, the licensee will use the BEACON system for measuring power distribution instead of using the rnoveable in-core flux mapping system when power is greater than 25% RTP. All existing power distribution limits remain unchanged. SCE&G will continue to perform power dictribution surveillances at the current frequency (every 31 effective full power days). The NRC staff has confirmed that the licensee has referenced and adhered to any restrictions and/or conditions the NRC imposed on j
WCAP-12472-P-A approval. SCE&G will use the BEACON system only with moveable in-core l
detectors, as the Westinghouse Topical Report does not apply to fixed in-core detectors.
The proposed TS 6.9.1.11 revision to add WCAP-1247-P-A,
- BEACON Core Monitoring and Operations Support System," August 1994, will ensure the values for cycle-specific parameters are maintained within the applicable limits of the plant safety analysis, thus ensuring
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F l l conformance to 10 CFR 50.36. The COLR will document the specific parameter limits resulting from VCSNS calculations, including mid-cycle or other revisions to parameter values and l
including the NRC-approved methodologies.
Since the proposed change to BEACON as a PDMS does not impact plant operation or safety and implementing the PDMS will continue to require operation within the core operational limits determined by NRC-approved methodologies, the staff finds that the proposed change is l
acceptable. Based on its review of the VCSNS analysis, the staff finds that SCE&G's request to implement the BEACON monitoring system and the proposed TS is acceptable.
3.0 STATE CONSULTATION
in accordance with the Commission's regulations, the State of South Carolina official was notified of the proposed issuance of the amendment. The State official had no comments.
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4.0 ENVIRONMENTAL CONSIDERATION
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The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that (1) the amendment involves no significant increase in the amounts and no significant change in the types of any effluents that 4
may be released offsite, and (2) that there is no significant increase in individual or cumulative l
occupcilional radiation exposure. The Commission has previously issued a proposed finding i
that the amendment involves no significant hazards consideration, and there has been no oublic comment on such finding (63 FR 64121). The amendment also changes recordkeeping or reporting requis 2nts. Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9) and (c)(10). Pursuant to 10 CFR 51.22(b) no environmental impact statem ent or environmental assessment need be prepared in connection j
with the issuance of the amendment.
5.0 CONCLUSION
The staff has reviewed the licensee's proposc2 VCSNS TS changes. Based on the staffs evaluation of the TS changes and the implementation requirements for using BEACON for measuring power distributions with moveable in-core detectors, the staff approves the proposed request to use BEACON at VCSNS to augment the flux mapping system when power is greater than 25% RTP.
l 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.
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, 6.0 REFERENCE 1.
Westinghouse Electric Corporation, WCAP-12472-P-A,
- BEACON Core Monitoring and Operations Support System" Topical Report, August 1994.
Principal Contributor: A. Attard Date: April 9, 199E l
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