ML18011A379
| ML18011A379 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 03/03/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML18011A378 | List: |
| References | |
| NUDOCS 9403100016 | |
| Download: ML18011A379 (10) | |
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+y*~4 UNITED STATES NUCLEAR REGULATORY COMMISSION WASNlNGTON, D.C. 2055&0001 SAFET EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.
46 TO FACILITY OPERATING LICENSE NO. NPF-63 CAROLINA POWER 5 LIGHT COMPANY SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1
DOCKET NO. 50-400
- 1. 0 INTRODUCTION By letter dated August 27,
- 1993, as supplemented February 17, 1994, the Carolina Power
& Light Company (CPKL or the licensee) submitted a request for changes to the Shearon Harris Nuclear Power Plant, Unit 1, (SHNPP) Technical Specifications (TS).
The request would revise the SHNPP TS 2. 1. 1, 2.2. 1,
- 3. 1. 1, 3.2.5, 3.9. 1, 5.4.2 and associated Bases to incorporate changes to reactor core safety limits, reactor trip system instrumentation setpoints, power distribution limits, and shutdown boron concentration control in support of the transition from nuclear fuel supplied by Westinghouse Electric Corporation to nuclear fuel supplied by Siemens Power Corporation (SPC or Siemens) and a reactor core safety average temperature reduction effort beginning with Cycle 6 operation.
The February 17, 1994, letter provided clarifying information within the scope of the original application and did not change the initial proposed no significant hazards consideration determination.
- 2. 0 EVALUATION The SHNPP will begin transition from nuclear fuel supplied by Westinghouse Electric Corporation to nuclear fuel designed and fabricated by SPC.
The transition will span 5 fuel cycles.
Cycles 6 through 10 will have a mixed fuel core of varying composition during the transition.
The SPC-designed fuel will be supported by SPC design methodology, while the Westinghouse fuel will continue to be supported by the original Westinghouse calculation.
Plant response will be supported by the SPC methodology.
The proposed changes to the current TS are related to three areas:
(1) the transition from Westinghouse-supplied fuel to SPC-supplied fuel; (2) efforts to reduce the primary coolant average temperature; and (3) shutdown boron concentration control.
Following are details of the staff evaluation.
- 2. 1 Transition Core-Related Chan es The reactor fuel supplied by Siemens (HTP) is somewhat different from that supplied by Westinghouse (LOPAR and Vantage
- 5) with respect to thermal, hydraulic, and neutronic characteristics.
Also, the methodologies used by Siemens to evaluate the accidents postulated in the Final Safety Analysis Report (FSAR) are different from the methodologies 9403100016 '940303 PDR ADOCK '05000400 p
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used by Westinghouse.
Accordingly, the SHNNP TS and Bases have been revised to reflect the transition differences as follows:
(a)
(b)
Specification
- 2. 1.1, Figure 2. 1-1, "Reactor Core Safety Limits Three Loops in Operation" The existing Figure 2. 1-1 was developed by Westinghouse for a core composed of only Westinghouse fuel assemblies.
These curves have been revised for the Cycle 6 core which is composed of both Siemens HTP and Westinghouse Vantage 5 and LOPAR fuel assemblies.
The new set of reactor safety limit curves have been established for the transition core using the approved Siemens HTP correlation.
The Bases associated with this Specification have also been revised to reflect the use of a transition core and the use of Siemens methodologies.
The staff has reviewed this TS change and associated Bases related to the transition and finds that the proposed TS change is acceptable since the approved methodologies are used and the departure from nucleate boiling ratio (DNBR) uncertainty is no longer applicable to the SHNPP Cycle 6 operation.
Specification 2.2. 1, Table 2.2-1, "Reactor Trip System Instrumentation Trip Setpoints" The upper limit of f(I) function deadband associated with the OTBT Reactor Trip function, Table 2.2-1 Functional Item 7, has been changed from <6.0 to +12.0 percent, since Siemens methodologies allow for a larger range of operating Axial Flux Distributions (AFDs) than Westinghouse methodologies.
The value of +12X was chosen for the value of q, q that would be expected to bound the possible normal operation axial flux difference for Cycle 6 and future cycles.
The Bases statements on Page B 2-4 associated with Table 2.2-1, Items 3 and 4, Power Ran e
Neutron Flux Hi h Rates, have been revised to reflect the deletion of the statement that no credit will be taken for the negative flux rate trip, since the Siemens analysis will take credit for the negative flux rate trip.
The negative flux rate trip is required to be operable by TS Table 2.2-1, Item 4, and Table 3.3-1, Item 4.
The Bases statements on Page B 2-5 associated with Table 2.2-1, Item 8, Overpower hT (OPBT),
have been revised to reflect the deletion of the reference to WCAP-9226 (a Westinghouse study of the Reactor Core Response to Excessive Secondary Steam Release).
The staff has reviewed the proposed changes and finds them acceptable since approved Siemens methodologies are used.
(c)
Specification Bases
- 3. 1. 1.3, "Moderator Temperature Coefficient" The Bases statements on Page B 3/4 1-2 describe an approach used by Westinghouse to determine the most negative MTC based on its relationship to MDC.
The description has been deleted since it refers to an approach that Siemens does not use.
Siemens uses Moderator Temperature Coefficient (MTC) rather than Moderator Density Coefficient (MDC) in its analytical models.
2.2 T,
Reduction Related Chan es The licensee has undertaken an effort to reduce the average coolant temperature in the reactor coolant system for Cycle 6 at SHNPP in order to extend the service life of the unit steam generators.
The T,, reduction affects the initial conditions assumed in the accident analyses.
The reduction in nominal T, at Rated Thermal Power is from 588.8 'F to 580.8 'F.
Accordingly, the SHNNP TS and Bases have been revised to reflect the transition differences as follows:
(a)
Specification 2.2. 1, Table 2.2-1 "Reactor Trip System Instrumentation Setpoints" The trip setpoint for OTBT (Note 1 on page 2-4 and page 2-8) and the trip setpoint for OPGT (Note 3 on page 2-4 and page 2-10) have been changed to reflect the T,, reduction.
This change improves both DNBR margin for those events mitigated. by the OTBT trip and margin to fuel melt and cladding strain for those overpower events mitigated by the OPET trip.
(b)
Specification 3.2.5, "DNB Parameters" The T, limit specified by TS 3.2.5.a and the Bases (page 3/4 2-14 and B 7/4 2-6) have been revised from 594. 1 'F to 586. 1 'F to reflect the 8 'F reduction in nominal T.
The difference between limit and nominal T,, (5.3 'F) remains Vhe same.
(c)
Specification 5.4.2, Reactor Coolant System Design Features-Volume The nominal T,, has been revised from 588.8 'F to 580.8 'F.
The staff has reviewed the proposed change and finds it=acceptable since the change would improve DNBR margin for those events mitigated by the OTBT trip.
la T
2.3 Shutdown Boron Concentration Control (a)
Specification 3.9. 1, Table 3.9-1 "Administrative Controls to Prevent Dilution During Refueling" The revision would replace the
">2000 ppm" with "the greater of 2000 ppm or the boron concentration required to maintain K,<< less than or equal to 0.95, as specified in the COLR."
The staff has reviewed the proposed revision and finds it acceptable since the addition of the wording to Table 3.9-1 eliminates the potential during Cycle 6 operation for a dilution path from the boric acid batch tank to the RCS when the RCS is required to be at a
minimum concentration greater than 2000 ppm.
Based on the above review, the staff concludes that the proposed TS changes are acceptable because of new approved Siemens methodologies used for safety analyses for Siemens fuel, an effort undertaken by the licensee to reduce primary coolant average temperature, and ensuring consistency within the plant TS and with accident analyses for Cycle 6 operations.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the State of North Carolina official was notified of the proposed issuance of the amendment.
The State official had no comments.
- 4. 0 ENVIRONMENTAL CONSIDERATION 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.
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 Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (58 FR 50966).
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 amendment.
- 5. 0 CONCLUSION The Commission has concluded, based on the considerations discussed
- above,
'hat:
(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,
e
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:
T. Huang Date:
March 3, 1994
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