ML20057A036
| ML20057A036 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 08/26/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20057A031 | List: |
| References | |
| NUDOCS 9309100328 | |
| Download: ML20057A036 (3) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION l
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WASHINGTON, D C. 20555-0001 l
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.138 TO FACILITY OPERATING LICENSE NPF-9 BRAMENDMENT NO.120 TO FACILITY OPERATING LICENSE NPF-17 DUKE POWER COMPANY MCCUIRE NUCLEAR STATION. UNITS 1 AND 2 y
DOCKET N05. 50-369 AND 50-370
1.0 INTRODUCTION
l By letter dated July 13, 1993, Duke Power Company (the licensee) submitted a request for changes to the McGuire Nuclear Station, Units 1 and 2, Technical j
Specifications (TS). The requested changes would increase the minimum J
Refueling Water Storage Tank (RWST) boron concentration to 2175 ppm, increase j
the minimum Cold leg Accumulator (CLA) boron concentration to 2000 ppm, and l
implement several administrative changes.
These changes are reflected in 1
proposed TS 3.1.2.5, 3.1.2.6, 3.5.1.1, 3.5.5, 3.9.1, 3.9.12, and 4.9.12, and j
2 the appropriate sections of the TS Bases. The staff's safety evaluation of j
the proposed changes follows.
I 2.0 EVALUATION 2.1 Chances to RWST Boron Concentrations In order to accommodate a core with a larger percentage of Mark-BW fuel in a
Cycle 9 and subsequent cycles, the licensee's Cycle 9 reload analysis showed that an increase in the RWST minimum boron concentration was required in order l
to meet shutdown margin requirements. The proposed minimum RWST boron i
j concentration is 2175 ppm and the licensee states that their analysis showed
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that this concentration is sufficient to maintain long-term sub-criticality l
l following a Loss of Coolant Accident (LOCA).
In order to maintain a 100 ppm operating window, it is proposed to increase the maximum boron concentration l
to 2275 ppm. The licensee's analysis of the above changes was performed with i
1 well established and NRC-approved meth us (Reference 1) using appropriate conservatism. The staff finds these ch mes acceptable.
1 Several changes are proposed for Unit 1 in order to reduce the differences between the two unit's TS. These changes involve increasing the maximum RWST baron concentration from 2100 ppm to '975 ppm and implementing the recirculation sump pH change discussed in the following section. The licensee's analysis of the above changes was performed with well established and NRC-approved methods (Reference 1) using appropriate conservatism. The staff finds these changes acceptable.
9309100328 930026 DR ADOCK 05000369 PDR
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. The RWST boron concentration change has prompted the licensee to make the following additional changes the Unit 1 TS:
1.
It is proposed to increase the minimum boron concentration in the
-fueling canal and the spent fuel pool to 2175 ppm to ensure that the i
hJST boron concentration will remain within specification following refueling operations. The staff considers this change acceptable because it meets the shutdown margin requirements.
2.
The minimum post-LOCA coolant pH has been revised from 8.5 to 7.5 due to the increased acidity of the water. The staff feels that this should not pose any additional threat of corrosion to the reactor vessel, piping, etc., because this pH value is above the minimum recommended value in the Standard Review Plan. Section 6.1.1 " Engineered Safety Features Materi al s. " The staf f, therefore, finds this change acceptable.
(Note that this change is also made to Unit 2 as previously discussed.)
3.
To preclude boron precipitation at this higher concentration, the licensee proposes to reduce tha hot leg racirculation initiation time from 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> to 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. The
.censee's analysis has shown this to be acceptable and the staff conco s in this finding.
2.2 Cold tea Accumulator Coten Chance The licensee's Unit 2, Cycle 9 reload analysis shcwed that in order to maintain post-LOCA sub-criticality, the CLA minimum boron concentration needs to be raised from 1900 ppm to 2000 ppm.
Furthermore, the licensee proposes to increase the maximum CLA baron concentration from 2100 ppm to 2275 ppm to maintain an operating margin. This change is also being applied to Unit 1 in order to maintain similar TS between the two units. The previously discussed changes to the post-LOCA pH and the hot leg recirculation initiat:an time are appropriate for these proposed CLA boron concentrations as well. The proposed CLA boron concentration changes were analyzed by the licensee using well established and NRC-approved methods (Reference 1) and the staff finds them acceptable.
The licensee also proposes to increase the volume weighted accumulator boron concentration from 1500 ppm to 1900 ppm for Unit 2 and from 1500 ppm to 1800 ppm for Unit 1.
This large change is necessary due to the fact that the i
minimum volume weighted boron concentration should have been increased to 1800 ppm for both units in their Cycle 8 reload report, but, as the licensee states, "...(was) inadvertently left out."
The proposed change from 1500 to 1900 ppm boron will bring Unit 2 up to the value required for Cycle 9 i
operation, and an increase to 1800 ppm for Unit I will bring Unit I up to an acceptable value for its current cycle.
The evaluation of the above changes was performed with well established and NRC-approved methods (Reference 1) and the staff finds them acceptable.
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i i l Based upon the above discussions, the staff concludes that the proposed TS changes relating to RWST and CLA boron concentrations are acceptable. The staff's conclusion is based upon the following:
1.
The referenced analysis used established techniques that were properly verified.
2.
The analysis was suitably conservative and bounding.
3.
The consequences of limiting accidents are acceptable.
4.
The proposed TS are consistent with the analyses provided.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the North Carolina State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 EjVIRONMENTAL CONSIDERATION The amendments change requirements 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 amendments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released off;ite, and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has previously issucd a proposed finding that the amendments involve no significant hazards consideration, and there has been no public commer.t en ::ch floding (58 FR 39581 dated July 23,1993).
Accordingly, the amendments meet 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 o ironmental assessment need be prepared in connection with the issuance of t2 4,
iments.
5.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health ano 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 amendments will not ce inimical to the common defense and security or to the health and safety of the public.
6.0 REFERENCE 1.
"DPC-NF-2010A, McGuire Nuclear Station / Catawba Nuclear Station Nuclear Physics Methodology for Reload Design," Duke Power Company, June 1985.
Principal Contributor:
T. Ulses Date:
August 26, 1993 i