ML22164A036
| ML22164A036 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Catawba, McGuire  |
| Issue date: | 07/19/2022 |
| From: | Stone Z Plant Licensing Branch II |
| To: | Pigott E, Simril R Duke Energy Carolinas |
| Stone Z | |
| References | |
| EPID L-2021-LLA-0198 | |
| Download: ML22164A036 (25) | |
Text
OFFICIAL USE ONLY - PROPRIETARY INFORMATION OFFICIAL USE ONLY - PROPRIETARY INFORMATION July 19, 2022 Mr. Tom Simril Site Vice President Catawba Nuclear Station Duke Energy Carolinas, LLC 4800 Concord Road York, SC 29745 Mr. Edward Pigott Site Vice President McGuire Nuclear Station Duke Energy Carolinas, LLC 12700 Hagers Ferry Road Huntersville, NC 28078
SUBJECT:
CATAWBA NUCLEAR STATION, UNITS 1 AND 2, AND MCGUIRE NUCLEAR STATION, UNITS 1 AND 2 ISSUANCE OF AMENDMENTS TO REVISE THE CONDITIONAL EXEMPTION OF THE END-OF-CYCLE MODERATOR TEMPERATURE COEFFICIENT MEASUREMENT METHODOLOGY (EPID L-2021-LLA-0198)
Dear Mr. Simril and Mr. Pigott:
The Nuclear Regulatory Commission (NRC, the Commission) has issued the enclosed Amendment No. 313 and 309 to Renewed Facility Operating License NPF-35 and NPF-52 for the Catawba Nuclear Station, Units 1 and 2, respectively, and Amendment Nos. 323 and 302 to Renewed Facility Operating License Nos. NPF-9 and NPF-17 for the McGuire Nuclear Station, Units 1 and 2, respectively. The amendments are in response to your application dated October 25, 2021, as supplemented by letter dated April 7, 2022.
The amendments revise the conditional exemption of the end-of-cycle moderator temperature coefficient measurement methodology which removes the incore quadrant power tilt conditional exemption acceptance criterion, adds an alternate approach for calculating the most negative moderator temperature coefficient (MTC) (i.e., the safety analysis MTC analysis value), and modifies the power distribution reaction rate failure criterion to prevent a false positive (criterion exceeded) due to an instrument issue. to this letter contains proprietary information. When separated from, this document is DECONTROLLED.
OFFICIAL USE ONLY - PROPRIETARY INFORMATION T. Simril and E. Pigott OFFICIAL USE ONLY - PROPRIETARY INFORMATION The NRC has determined that the related safety evaluation (SE) contains proprietary information pursuant to Title 10 of the Code of Federal Regulations Section 2.390, Public inspections, exemptions, requests for withholding. The proprietary information is indicated by text enclosed within double brackets. Accordingly, the NRC staff has also prepared a non-proprietary publicly available version of the SE, which is provided as Enclosure 6. The proprietary version of the SE is provided as Enclosure 5.
A Notice of Issuance will be included in the Commissions monthly Federal Register notice.
If you have any questions, please contact me at 301-415-0615 or by e-mail at Zackary.Stone@nrc.gov.
Sincerely,
/RA/
Zackary Stone, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-413, 50-414, 50-369, and 50-370
Enclosures:
- 1. Amendment No. 313 to NPF-35
- 2. Amendment No. 309 to NPF-52
- 3. Amendment No. 323 to NPF-9
- 4. Amendment No. 302 to NPF-17
- 5. Safety Evaluation (proprietary)
- 6. Safety Evaluation (non-proprietary) cc w/Enclosure 1, 2, 3, 4, and 6: Listserv DUKE ENERGY CAROLINAS, LLC NORTH CAROLINA ELECTRIC MEMBERSHIP CORPORATION DOCKET NO. 50-413 CATAWBA NUCLEAR STATION, UNIT 1 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 313 Renewed License No. NPF-35 1.
The Nuclear Regulatory Commission (NRC, the Commission) has found that:
A.
The application for amendment to the Catawba Nuclear Station, Unit 1 (the facility) Renewed Facility Operating License No. NPF-35 filed by the Duke Energy Carolinas, LLC, acting for itself, and North Carolina Electric Membership Corporation (the licensees), dated October 25, 2021, as supplemented by letter dated April 7, 2022, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations as set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commissions regulations set forth in 10 CFR Chapter I; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commissions regulations and all applicable requirements have been satisfied.
2.
Accordingly, by Amendment No. 313, Renewed Facility Operating License No. NPF-35, is hereby amended to accept the revision of the conditional exemption of the end-of-cycle moderator temperature coefficient measurement methodology as described in the application and supplement.
3.
This license amendment is effective as of its date of issuance and shall be implemented by the completion of refueling outage C1R27 (Spring 2023).
FOR THE NUCLEAR REGULATORY COMMISSION Michael T. Markley, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance: July 19, 2022
/RA - S. Williams for/
DUKE ENERGY CAROLINAS, LLC NORTH CAROLINA MUNICIPAL POWER AGENCY NO. 1 PIEDMONT MUNICIPAL POWER AGENCY DOCKET NO. 50-414 CATAWBA NUCLEAR STATION, UNIT 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 309 Renewed License No. NPF-52 1.
The Nuclear Regulatory Commission (NRC, the Commission) has found that:
A.
The application for amendment to the Catawba Nuclear Station, Unit 2 (the facility) Renewed Facility Operating License No. NPF-52 filed by the Duke Energy Carolinas, LLC, acting for itself, North Carolina Municipal Power Agency No. 1 and Piedmont Municipal Power Agency (the licensees), dated October 25, 2021, as supplemented by letter dated April 7, 2022, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations as set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commissions regulations set forth in 10 CFR Chapter I; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commissions regulations and all applicable requirements have been satisfied.
2.
Accordingly, by Amendment No. 309, Renewed Facility Operating License No. NPF-52, is hereby amended to accept the revision of the conditional exemption of the end-of-cycle moderator temperature coefficient measurement methodology as described in the application and supplement.
3.
This license amendment is effective as of its date of issuance and shall be implemented by the completion of refueling outage C2R26 (Spring 2024).
FOR THE NUCLEAR REGULATORY COMMISSION Michael T. Markley, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance: July 19, 2022
/RA - S. Williams for/
DUKE ENERGY CAROLINAS, LLC DOCKET NO. 50-369 MCGUIRE NUCLEAR STATION, UNIT 1 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 323 Renewed License No. NPF-9 1.
The Nuclear Regulatory Commission (NRC, the Commission) has found that:
A.
The application for amendment to the McGuire Nuclear Station, Unit 1 (the facility), Renewed Facility Operating License No. NPF-9, filed by the Duke Energy Carolinas, LLC (the licensee), dated October 25, 2021, as supplemented by letter dated April 7, 2022, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations as set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations set forth in 10 CFR Chapter I; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
Accordingly, by Amendment No. 323, Renewed Facility Operating License No. NPF-9, is hereby amended to accept the revision of the conditional exemption of the end-of-cycle moderator temperature coefficient measurement methodology as described in the application and supplement.
3.
This license amendment is effective as of its date of issuance and shall be implemented by the completion of refueling outage M1R29 (Fall 2023).
FOR THE NUCLEAR REGULATORY COMMISSION Michael T. Markley, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance: July 19, 2022
/RA - S. Williams for/
DUKE ENERGY CAROLINAS, LLC DOCKET NO. 50-370 MCGUIRE NUCLEAR STATION, UNIT 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 302 Renewed License No. NPF-17 1.
The Nuclear Regulatory Commission (NRC, the Commission) has found that:
A.
The application for amendment to the McGuire Nuclear Station, Unit 2 (the facility), Renewed Facility Operating License No. NPF-17, filed by the Duke Energy Carolinas, LLC (the licensee), dated October 25, 2021, as supplemented by letter dated April 7, 2022, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations as set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations set forth in 10 CFR Chapter I; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
2.
Accordingly, by Amendment No. 302, Renewed Facility Operating License No. NPF-17, is hereby amended to accept the revision of the conditional exemption of the end-of-cycle moderator temperature coefficient measurement methodology as described in the application and supplement.
3.
This license amendment is effective as of its date of issuance and shall be implemented by the completion of refueling outage M2R28 (Spring 2023).
FOR THE NUCLEAR REGULATORY COMMISSION Michael T. Markley, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance: July 19, 2022
/RA - S. Williams for/
ENCLOSURE 6 NON-PROPRIETARY SAFETY EVALUATION FOR AMENDMENT NOS. 313 AND 309 TO RENEWED FACILITY OPERATING LICENSE NPF-35 AND NPF-52 DUKE ENERGY CAROLINAS, LLC CATAWBA NUCLEAR STATION, UNITS 1 AND 2 DOCKET NOS. 50-413 AND 50-414 AND LICENSE AMENDMENT NOS. 323 AND 302 TO RENEWED FACILITY OPERATING LICENSE NPF-9 AND NPF-17 MCGUIRE NUCLEAR STATION, UNITS 1 AND 2 DOCKET NOS. 50-369 AND 50-370
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR AMENDMENT NOS. 313 AND 309 TO RENEWED FACILITY OPERATING LICENSE NPF-35 AND NPF-52 DUKE ENERGY CAROLINAS, LLC CATAWBA NUCLEAR STATION, UNITS 1 AND 2 DOCKET NOS. 50-413 AND 50-414 AND LICENSE AMENDMENT NOS. 323 AND 302 TO RENEWED FACILITY OPERATING LICENSE NPF-9 AND NPF-17 MCGUIRE NUCLEAR STATION, UNITS 1 AND 2 DOCKET NOS. 50-369 AND 50-370
1.0 INTRODUCTION
By application dated October 25, 2021 (Reference 1), as supplemented by letter dated April 7, 2022 (Reference 2), Duke Energy Carolinas, LLC (Duke, the licensee), requested changes to DPC-NE-1007-PA, Revision 0, Conditional Exemption of the EOC [End of Cycle]
MTC [Moderator Temperature Coefficient] Measurement Methodology, (Reference 3),
(Reference 4), (Reference 5), and (Reference 6), a methodology used to meet Surveillance Requirement (SR) 3.1.3.2 in lieu of an EOC MTC measurement for the Catawba Nuclear Station, Units 1 and 2 (CNS or Catawba), and the McGuire Nuclear Station, Units 1 and 2 (MNS or McGuire).
The proposed changes would remove the incore quadrant power tilt conditional exemption acceptance criterion, add an alternate approach for calculating the most negative MTC (i.e., the safety analysis MTC analysis value), and modify the power distribution reaction rate failure criterion to prevent a false positive (criterion exceeded) due to an instrument issue.
From March 1 to March 2, 2022, the U.S. Nuclear Regulatory Commissions (NRC) staff conducted an audit to support its review of the amendment request, as discussed in the NRC staffs audit plan dated February 18, 2022 (Reference 7), and audit summary dated
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION March 15, 2022 (Reference 8). The supplement dated April 7, 2022, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the staffs original proposed no significant hazards consideration determination as published in the Federal Register on February 8, 2022 (87 FR 7211).
The NRC staffs safety evaluation (SE) contains proprietary information as originally submitted by letter dated October 25, 2021, as supplemented by letter dated April 7, 2022. Proprietary information withheld under Title 10 of the Code of Federal Regulations (10 CFR) Section 2.390 is identified by text enclosed within double brackets as shown here (( )).
2.0 REGULATORY EVALUATION
2.1 Description of System
SR 3.1.3.2 requires the licensee to measure MTC within seven effective full power days of reaching the equivalent of an equilibrium core boron concentration of 300 parts per million (ppm). The measured value of MTC is then compared to the surveillance limit as specified in the core operating limits report (COLR). This demonstrates that limiting condition of operation (LCO) 3.1.3, Moderator Temperature Coefficient, is met which ensures that the MTC is within the limits assumed in the licensees accident or transient analysis, as documented in the Catawba and McGuire Updated Final Safety Analysis Reports (UFSARs) (Reference 9) and (Reference 10). If the MTC is more negative than assumed in certain accident and transient analyses, then the magnitude of power excursions caused by overcooling will be underestimated.
The Duke Energy methodology report, DPC-NE-1007-PA, Revision 0, describes a methodology by which EOC MTC measurement may be exempted, provided that the revised predicted MTC is less negative than the SR 3.1.3.2 limit specified in the COLR and measurements of other core operating characteristics (assembly power, incore quadrant tilt, core reactivity difference, beginning of cycle (BOC) hot zero power MTC, individual control bank worth, and total control bank worth) are consistent with design predictions.
The revised predicted MTC is the design prediction of EOC MTC adjusted to account for uncertainty in the prediction and corrections for ((
)) The requirements that other core operating characteristics be consistent with design predictions provide assurance that the prediction of MTC can be relied on. These requirements are referred to as benchmark criteria throughout this document.
2.2 Description of Proposed Change The licensee proposed three changes to the methodology in DPC-NE-1007-PA, Revision 0.
One change adds an alternate approach for calculating the difference between the safety analysis MTC and the LCO 3.1.3 MTC limit. The current method assesses the change in MTC ((
))
The other two changes modify the benchmark criteria of the method. One of these changes removes the intermediate power and full power incore quadrant power tilt benchmark criteria.
The other change would modify the assembly power benchmark criterion so that a faulty measurement does not result in violation of the criterion.
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION Additionally, the licensee proposed administrative changes to DPC-NE-1007-PA, Revision 0, to update the revision number and report date, fix grammatical errors, and adjust numbering of tables.
2.3 Regulatory Requirements and Guidance Documents The regulations in 10 CFR 50.36(b) states, in part:
The technical specifications will be derived from the analyses and evaluation included in the safety analysis report, and amendments thereto, submitted pursuant to [10 CFR] 50.34.
The regulations in 10 CFR 50.36(c)(2), Limiting conditions for operation, states, in part:
Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility. When a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met.
The regulations in 10 CFR 50.36(c)(3), Surveillance requirements, states, in part:
Surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met.
Regulatory Guide 1.105, Revision 4, Setpoints for Safety-Related Instrumentation, (Reference
- 11) describes an approach that is acceptable for ensuring that setpoints for safety-related instrumentation are initially within and remain within technical specification limits.
The Westinghouse report, WCAP-14851-A, Safety Evaluation Supporting the Conditional Exemption of the Most Negative EOL [end of life] Moderator Temperature Coefficient (Reference 12) is an example of a generic NRC-approved topical report that, like DPC-NE-1007-P, allows for conditional exemption of EOC MTC measurement.
American National Standards Institute (ANSI)/International Society of Automation (ISA) 67.04.01-2018, Setpoints for Nuclear Safety-Related Instrumentation, (Reference 13) is endorsed to be used in complying with the regulations to ensure that: (a) setpoints for safety-related instrumentation are established to protect nuclear powerplant safety and analytical limits, and (b) the maintenance of instrument channels implementing these setpoints ensures they are functioning as required, consistent with the plant technical specifications.
ANSI/American Nuclear Society (ANS)-19.11-2017, Calculation and Measurement of the Moderator Temperature Coefficient of Reactivity for Pressurized Water Reactors (Reference
- 14) is a third-party standard intended to provide guidance and specify criteria for the calculation and measurement of the MTC of reactivity in pressurized water reactors.
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3.0 TECHNICAL EVALUATION
The NRC staff evaluated the proposed changes to the method to ensure that SR 3.1.3.2 continues to verify that LCO 3.1.3 is met, and that meeting LCO 3.1.3 ensures that actual MTC is bounded by the value assumed in the Catawba and McGuire UFSAR accident and transient analysis.
3.1 Relationship Between the Technical Specification 3.1.3 Limit and the Most Negative MTC Section 2.2 of DPC-NE-1007-P, Revision 1, describes the relationship between the MTC assumed in the safety analyses and the LCO 3.1.3 MTC. The most negative MTC permitted by LCO 3.1.3 is defined at the all rods out condition. However, LCO 3.1.6, Control Bank Insertion Limits, and LCO 3.2.3, Axial Flux Difference, permit a range of control rod positions and axial flux difference, some of which result in a more negative MTC. The LCO 3.1.3 MTC is less negative than the safety analysis MTC because the LCOs, which are derived from the safety analyses, include some margin to assure that operation will be within the bounds of the initial conditions assumed in the safety analysis. The difference accounts for, among other things, variations in ((
)) and instrumentation uncertainty.
The approved DPC-NE-1007-PA, Revision 0, describes a ((
)) procedure for calculating the difference between the safety analysis and LCO 3.1.3 MTC. In this approach, ((
))
The NRC staff reviewed the licensees proposed approach for ((
)) As part of the licensees approach, they confirmed that the set of effects considered is complete, assessed the magnitude of each effect, and clarified that ((
)) This SE discusses the completeness of the set of terms and the value of each term, however, only the ((
)) is modified by the licensees proposed changes.
3.1.1 Completeness of set of terms The licensee considered perturbations to MTC from ((
)) In the Selection of Key Parameters Section of Reference 2, the licensee justified why the terms in equation 1 of DPC-NE-1007-P, Revision 1, represent the complete set contributing to the difference between the LCO 3.1.3 MTC and the MTC assumed in the safety analysis. ((
))
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION As a point of comparison, the NRC staff considered discussion in Section 2.4, Conservatism of the Most Negative Feasible MTC Conversion, of WCAP-14851-A and the recommendations in Section 6.2, Extrapolation, of ANSI/ANS-19.11-2017 (Ref. 13). These documents list the following variables as important to the calculation of MTC:
Moderator temperature
Pressure
Axial flux difference
Control rod position
Reactor power
Boron concentration
Xenon concentration
((
))
Based on the above, and because the set of terms is not modified by the proposed revision, the NRC staff finds that the licensee included the important terms affecting MTC for the purpose of determining the difference between the LCO 3.1.3 limit and the MTC assumed in the accident and transient analyses.
3.1.2 Values of terms The licensees method assesses MTC ((
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION
))
The licensee stated that ((
)) The licensee explained that these uncertainties reflect larger variation than is typically encountered during operation and provided a frequency distribution of actual ((
)) in their supplement dated April 7, 2022, to support their claim. ((
)) The NRC staff finds that these frequency distributions support the conservatism of ((
)) modeled by the licensees method.
Due to the consistency of methods of determining ((
)) with existing guidance, the conservatism of the ((
)), and because the method of determining values of these allowances is not changed by the proposed revision, the NRC staff finds that the licensee has appropriately justified the approach in determining values of these allowances.
3.1.3 Independence of terms The licensee provided justification for ((
)), since this is implicitly assumed by the licensees ((
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION
)) Therefore, the NRC staff finds the licensees ((
)) to be acceptable.
Since the licensee adequately justified the independence of its terms, the NRC staff finds that the proposed method of calculating margin between the safety analysis MTC and LCO 3.1.3 MTC conservatively accounts for the difference attributable to instrumentation uncertainty and the range of conditions permitted by technical specifications.
3.2 Removal of Measured Incore Quadrant Power Tilt Criterion The Duke Energy methodology report, DPC-NE-1007-PA, Revision 0, included seven benchmark criteria that must be met for the licensee to be exempted from the SR 3.1.3.2 requirement to measure MTC. The proposed revision would remove the full power and intermediate power incore quadrant tilt benchmark criteria. This change is described in Change 3-1: Confirmation of Reactor Core Performance (Section 3.3) and associated Technical Justification sections of Attachment 2 to the licensees submittal dated October 25, 2021.
The Technical Justification Section states that the licensee has used the conditional exemption methodology for ((
)) cores, ((
)) of which violated the incore tilt benchmark criterion. The licensee measured MTC each time the incore tilt benchmark criterion was violated in accordance with SR 3.1.3.2. ((
)) This data was compared with that used to establish the predictive bias and uncertainty in MTC during review of DPC-NE-1007-P, Revision 0.
Few measurements are available to assess the effect of violating the incore tilt criterion on MTC prediction because most of the Catawba and McGuire cores have met the incore tilt benchmark criterion since DPC-NE-1007-PA, Revision 0, was adopted. Further, it is unclear whether incore
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION tilt criteria were met for the data in the comparison (DPC-NE-1007-PA, Revision 0) set. Although limited in statistical power, the new data does not indicate that the predictive bias and uncertainty in MTC established during review of DPC-NE-1007-P, Revision 0, is inapplicable when the incore tilt criterion is violated.
((
)) The incore quadrant tilt criterion accounts for flux asymmetry between core quadrants. The licensee performed two analytical studies to examine the effect of flux asymmetry between core quadrants on MTC. In the first, ((
)) This would violate the incore tilt benchmark criterion. ((
)) As points of comparison, the difference between the TS 3.1.3 MTC limit defined in the COLRs for Catawba Units 1 and 2 (Reference 16) and (Reference 17), and McGuire, Units 1 and 2 (Reference 18) and (Reference 19), and the MTC assumed in the accident and transient analysis (as documented in Table 15-4 the Catawba and McGuire UFSAR) is 8 pcm/°F.
The licensees second study considered an ((
)) The licensee stated that this scenario is highly improbable because it assumes that the defective fuel is located in the same core quadrant with manufacturing defects that are consistently biased in one direction relative to the design specification, and that fuel with these defects are loaded in the same quadrant of the core through random chance. ((
))
The licensee stated that both studies demonstrate the ((
))
The NRC staff reviewed the licensees calculations and finds that they demonstrated the ((
))
associated with quadrant power tilts. Because the ((
)), the NRC staff finds that removing this criterion will not result in reduced assurance of the accuracy of the MTC prediction. Additionally, other benchmark criteria, such as the assembly power benchmark criterion, will continue to require measurement of EOC MTC in the event that the power distribution is not as designed. Since the revised set of benchmark criteria will still provide assurance that the MTC prediction reflects the as-loaded core, performing the revised surveillance methodology will continue to provide assurance that LCO 3.1.3 is met. The NRC staff finds that this change is consistent with 10 CFR 50.36(c)(3) and is therefore, acceptable.
3.3 Modification of Assembly Power Criterion The licensee proposed to modify the assembly power benchmark criterion that must be met for the SR 3.1.3.2 requirement to measure MTC to be suspended. This change is described in Change 3-2: Confirmation of Reactor Core Performance (Section 3.3) and associated Technical Justification sections of Attachment 2 to the licensees submittal dated
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION October 25, 2021. Assembly power is measured at multiple instances throughout the cycle, as specified by TS 3.2.1, Heat Flux Hot Channel Factor FQ(X,Y,Z) and TS 3.2.2, Nuclear Enthalpy Rise Hot Channel Factor (FH(X,Y). In each instance, data is obtained in multiple locations throughout the core. Currently, all these measurements must be within +/-10 percent of the predicted value to exempt the EOC MTC measurement requirement.
The licensee proposed to modify this requirement so that one measurement is permitted to differ from the predicted value by more than +/-10 percent. Specifically, the criterion is not failed unless two ((
))
The licensee stated that the purpose of this change is to eliminate the condition where a bad measurement due to an instrument issue causes the benchmark criterion to be violated. They also stated that ((
))
The NRC staff reviewed the licensees arguments and agrees that a failed instrument does not indicate that the core is behaving differently than designed, and therefore preventing exemption of the MTC measurement due to a failed instrument is not consistent with the purpose of the conditional exemption methodology benchmark criteria. The NRC staff also finds the licensees assertion reasonable that ((
)) The NRC staff finds that the proposed revision does not degrade the ability of this benchmark criterion to detect deficiencies in the as-loaded core or the design prediction. The DPC-NE-1007-P, Revision 1, methodology will continue to provide assurance that LCO 3.1.3 is met because the revised assembly power benchmark criterion will still detect deficiencies in the as-loaded core or design predictions. Because performing the revised surveillance methodology will continue to assure that LCO 3.1.3 is met, this change is consistent with 10 CFR 50.36(c)(3) and the NRC staff find it acceptable.
3.4 Editorial Changes In addition to the changes discussed in Sections 0, 3.2, and 3.3 of this SE, the licensee also proposed multiple editorial changes to DPC-NE-1007-PA, Revision 0. These changes reflect the change in the date of the report and the revision number, fix grammatical errors, and adjust numbering of tables to be consistent with other changes in the document. Since these changes do not alter the implementation of SR 3.1.3.2, the NRC staff finds them acceptable.
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3.5 NRC Staff Conclusion
The NRC staff reviewed the proposed changes to DPC-NE-1007-P, Revision 1, with respect to the requirements of limiting conditions for operation and surveillance requirements described in 10 CFR 50.36(c)(2)(i) and 10 CFR 50.36(c)(3). The NRC staff finds that since the MTC is ((
)) and since the revised assembly power criterion will still detect deficiencies in the as-loaded core or design predictions, the revised set of benchmark criteria, if met, will continue to provide assurance that the MTC prediction reflects the as-loaded core. Therefore, meeting the revised surveillance requirement will assure that LCO 3.1.3 is met consistent with 10 CFR 50.36(c). The NRC staff also finds that the licensees proposed ((
)) method of calculating the difference between the LCO and safety analysis MTC will continue to result in an LCO that, if met, will ensure that actual core conditions are more favorable than the initial conditions of the accident and transient analyses.
Additionally, the NRC staff finds that the conclusions reached during review of DPC-NE-1007-PA, Revision 0, are not changed by the proposed revision. Therefore, the NRC staff finds these changes acceptable.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the South Carolina and North Carolina State official was notified of the proposed issuance of the amendments on June 7, 2022. On June 15, 2022, the State official confirmed that the State of South Carolina had no comments.
On June 10, 2022, the State official confirmed that the State of North Carolina had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change the requirements with respect to the installation or use of facility components 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 published in the Federal Register on February 8, 2022 (87 FR 7211), and there has been no public comment on such finding. 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 environmental assessment need be prepared in connection with the issuance of the amendments.
6.0 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 operation in the proposed manner, (2) there is reasonable assurance that 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.
OFFICIAL USE ONLY PROPRIETARY INFORMATION
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION 1 Gibby, Shawn, Duke Energy, letter to U.S. Nuclear Regulatory Commission, "Revision 1 of DPC-NE-1007-P, 'Conditional Exemption of the EOC MTC Measurement Methodology',"
October 25, 2021 (Agencywide Documents Access and Management System (ADAMS)
Accession Nos. ML21298A133, ML21298A134 (non-public)).
2 Gibby, Shawn, Duke Energy, letter to U.S. Nuclear Regulatory Commission, "Response to Request for Additional Information (RAI) Regarding Revision 1 of DPC-NE-1007-P,
'Conditional Exemption of the EOC MTC Measurement Methodology'," April 7, 2022 (ML22097A035 and ML22097A036 (non-pubilc)).
3 Hamrick, George T., Duke Energy, letter to U.S. Nuclear Regulatory Commission, "LIcense Amendment Request for Conditional Exemption of the End of Cycle (EOC) MTC Measurement Methodology," May 31, 2012 (ML121530441).
4 Capps, Steven D., Duke Energy, letter to U.S. Nuclear Regulatory Commission, "Response to NRC Request for Additional Information," March 13, 2013 (ML130740281).
5 Henderson, Kelvin, Duke Energy, letter to U.S. Nuclear Regulatory Commission, "Response to NRC Request for Additional Information Dated October 24, 2014," November 25, 2014 (ML14332A299).
6 Miller, G. Edward, NRC, letter to Steven Capps and Kevin Henderson, Duke Energy, "Issuance of Amendment Re: Technical Specifications (TS) 3.1.3, 'Moderator Temperature Coefficient (MTC)' and TS 5.6.5, 'Core Operating Limits Report,'," April 14, 2015 (ML15063A271).
7 Stone, Zackary, NRC, letter to Robert T. Simril and Tom Ray, Duke Energy, "Regulatory Audit in Support of the License Amendment Request for Revision to the Conditional Exemption of the End of Cycle Moderator Temperature Coefficient Measurement Methodology," February 18, 2022 (ML22040A127).
8 Stone, Zackary, NRC, letter to Robert T. Simril and Tom Ray, Duke Energy, "Regulatory Audit Summary Regarding License Amendment Request for Revision to the Conditional Exemption of the End of Cycle Moderator Temperature Coefficient Measurement Methodology," March 15, 2022 (ML22070B075).
9 Simril, Tom, Duke Energy, letter to U.S. Nuclear Regulatory Commission, "Submittal of Updated Final Safety Analysis Report (Revision 22)," October 28, 2021 (ML21301A203).
10 Pigott, Edward R., Duke Energy, letter to U.S. Nuclear Regulatory Commission, "Submittal of Updated Final Safety Analysis Report (UFSAR) Revision 23," April 7, 2022 (ML22097A086).
11 U.S. Nuclear Regulatory Commission, "Regulatory Guide 1.105, Revision 4 - Setpoints for Safety-Related Instrumentation," February 2021 (ML20330A329).
12 Westinghouse Electric Corporation, WCAP-14851-A (Public) and WCAP-13749-P-A (Non-Public), "Safety Evaluation Supporting the Conditional Exemption of the Most Negative EOL Moderator Temperature Coefficient Measurement," 1997 (ML20140D215, ML14358A301 (non-public)).
13 American National Standards Institute/International Society of Automation, Standard 67.04.01-2018, "Setpoints for Nuclear Safety-Related Instrumentation," ISA, Research Triangle Park, NC, 2018.
14 American National Standards Institute/American Nuclear Society, Standard 19.11-2017, "Calculation and Measurement of the Moderator Temperature Coefficient of Reactivity for Pressurized Water Reactors," ANS, La Grange Park, IL, 2017.
7.0 REFERENCES
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION 15 International Society of Automation, ISA-RP67.04.02-2010, "Methodologies for the Determination of Setpoints for Nuclear Safety-Related Instrumentation," Research Triangle Park, NC, 2010.
16 Simril, Tom, Duke Energy, letter to U.S. Nuclear Regulatory Commission, "Core Operating Limits Report (COLR) for Unit 1 Cycle 27 Reload Core, Revisions 1, 2, and 3," November 9, 2021 (ML21313A181).
17 Simril, Tom, Duke Energy, letter to U.S. Nuclear Regulatory Commission, "Core Operating Limits Report (COLR) for Unit 2 Cycle 25 Reload, Rev. 2," March 24, 2022 (ML22083A055).
18 Ceva, Celeste, Duke Energy, letter to U.S. Nuclear Regulatory Commission, "McGuire Unit 1, Cycle 29, Revision 0, Core Operating Limits Report (COLR)," April 21, 2021 (ML22111A296).
19 Ray, Thomas D., Duke Energy, letter to U.S. Nuclear Regulatory Commission, "McGuire Unit 2, Cycle 28, Revision 0, Core Operating Limits Report (COLR)," October 14, 2021 (ML21291A004).
Principal Contributors:
A. Rau, NRR Date: July 19, 2022
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