ML22063B178
| ML22063B178 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Catawba, McGuire  |
| Issue date: | 03/09/2022 |
| From: | Stone Z Plant Licensing Branch II |
| To: | Teresa Ray, Simril R Duke Energy Carolinas |
| Stone, Z. | |
| Shared Package | |
| ML22063B180 | List: |
| References | |
| EPID L-2021-LLA-0198 | |
| Download: ML22063B178 (7) | |
Text
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION March 9, 2022 Mr. Robert T. Simril Site Vice President Catawba Nuclear Station Duke Energy Carolinas, LLC 4800 Concord Road York, SC 29745 Mr. Tom Ray 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 - REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST FOR REVISION TO THE CONDITIONAL EXEMPTION OF THE END OF CYCLE MODERATOR TEMPERATURE COEFFICIENT MEASUREMENT METHODOLOGY (EPID L-2021-LLA-0198)
Dear Mr. Simril and Mr. Ray:
By letter dated October 25, 2021, Duke Energy Carolinas, LLC (Duke Energy) submitted a license amendment request (LAR) for Catawba Nuclear Station, Units 1 and 2, and McGuire Nuclear Station, Units 1 and 2. The LAR proposed to remove the incore quadrant power tilt conditional exemption acceptance criterion, add an alternate approach for calculating the most negative moderator temperature coefficient (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.
The U.S. Nuclear Regulatory Commission (NRC) staff has determined that additional information is needed as discussed in the Enclosure. On March 8, 2022, Mr. Joshua Duc of your staff agreed that Duke Energy would respond within 30 days of the date of this letter.
The NRC staffs request for additional information contains proprietary information as originally submitted in the letter dated October 25, 2021. Proprietary information withheld under Title 10 of the Code of Federal Regulations, Section 2.390 (10 CFR 2.390) is identified by text enclosed within double brackets as shown here (( )). A non-proprietary version of the RAI is provided as.
to this letter contains proprietary information. When separated from, this document is DECONTROLLED.
OFFICIAL USE ONLY PROPRIETARY INFORMATION R. T. Simril and OFFICIAL USE ONLY PROPRIETARY INFORMATION If you have any questions, please contact me at 301-415-0615 or via e-mail at Zackary.Stone@nrc.gov.
Sincerely,
/RA/
Zackary R. 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.
Request for Additional Information (Proprietary)
- 2.
Request for Additional Information (Non-Proprietary) cc: Listserv, w/o Enclosure 1
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION ENCLOSURE 2 NON-PROPRIETARY VERSION REQUEST FOR ADDITIONAL INFORMATION CATAWBA NUCLEAR STATION, UNITS 1 AND 2 MCGUIRE NUCLEAR STATION, UNITS 1 AND 2 DUKE ENERGY CAROLINAS, LLC LICENSE AMENDMENT REQUEST FOR REVISION TO THE CONDITIONAL EXEMPTION OF THE END OF CYCLE MODERATOR TEMPERATURE COEFFICIENT MEASUREMENT METHODOLOGY DOCKET NOS. 50-413, 50-414, 50-369, AND 50-370
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION REQUEST FOR ADDITIONAL INFORMATION CATAWBA NUCLEAR STATION, UNITS 1 AND 2 MCGUIRE NUCLEAR STATION, UNITS 1 AND 2 DUKE ENERGY CAROLINAS, LLC LICENSE AMENDMENT REQUEST FOR REVISION TO THE CONDITIONAL EXEMPTION OF THE END OF CYCLE MODERATOR TEMPERATURE COEFFICIENT MEASUREMENT METHODOLOGY DOCKET NOS. 50-413, 50-414, 50-369, AND 50-370 By letter dated October 25, 2021, (Agencywide Documents Access and Management System Accession (ADAMS) No. ML21298A133) Duke Energy Carolinas, LLC (Duke Energy) submitted a license amendment request (LAR) for Catawba Nuclear Station, Units 1 and 2, and McGuire Nuclear Station, Units 1 and 2. The LAR proposed to remove the incore quadrant power tilt conditional exemption acceptance criterion, add an alternate approach for calculating the most negative moderator temperature coefficient (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.
The U.S. Nuclear Regulatory Commission (NRC) staffs request for additional information (RAI) contains proprietary information as originally submitted in the letter dated October 25, 2021.
Proprietary information withheld under Title 10 of the Code of Federal Regulations, Section 2.390 (10 CFR 2.390) is identified by text enclosed within double brackets as shown here (( )).
Regulatory Basis:
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) requires that licensees include in their technical specifications limiting conditions for operation that reflect the lowest functional capability or performance levels of equipment required for safe operation of the facility.
The regulations in 10 CFR 50.36(c)(2)(ii)(B) requires that limiting conditions for operation be established for process variables that are initial conditions of a design basis accident or transient analysis that either assumes the failure of or presents a challenge to the integrity of a fission product barrier.
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION The regulations in 10 CFR 50.36(c)(3) requires that licensees include in their technical specification surveillance requirements related to test, calibration, or inspection to assure that the limiting conditions for operation will be met.
The following RAIs are made in view of clarifying the relationship of Limiting Conditions for Operation 3.1.3 to the initial conditions of the Updated Final Safety Analysis Report transient analysis and ensuring that the conditional exemption methodology in Surveillance Requirement 3.1.3.2 serves the function of a surveillance requirement.
Background for RAI-01, RAI-02, RAI-03 The Safety Analysis (SA) MTC calculation, as described in the licensees technical justification change 2-1 of DPC-NE-1007-P, Rev. 1, (ADAMS Accession No. ML21298A133, (ML21298A134
- non-public)), is the following:
The SA MTC is calculated by considering its mean and standard deviation separately. The mean of SA MTC is represented by equation (1).
(1)
Where each represents the mean (or bias) of a different parameter which impacts the SA MTC. Thus, the total mean of SA MTC is the summation of these individual means. The standard deviation of SA MTC is represented by equation (2).
(2)
The SA MTC is calculated by combining the mean and the variance as given in equation (3).
(3)
RAI-01
Please provide a description of each term (i.e., each ) in equation (1) above. Please describe what source of uncertainty is represented by the term and provide justification of the value chosen. Please confirm that the set of terms considered is the complete set of terms which could bias the SA MTC.
RAI-02
Please provide a description of each term (i.e., each ) in equation (2) above. Please describe what source of uncertainty is represented by the term and provide justification of the value chosen. Please confirm that the set of terms considered is the complete set of terms which could impact the variance of the SA MTC and provide justification that each term can be treated independently of the others.
OFFICIAL USE ONLY PROPRIETARY INFORMATION OFFICIAL USE ONLY PROPRIETARY INFORMATION
RAI-03
Please provide the value of the multiplier (i.e., the term) in equation (3) above, and please justify the choice of this value.
RAI-04
In the ((
)) Other mechanisms of introducing a quadrant power tilt may not produce similar compensating effects within each quadrant. It is unclear whether effects between quadrants will average out for larger tilts. Please discuss other plausible mechanisms of introducing incore tilt, and whether these might have a greater impact on the MTC and require the inclusion of an incore flux tilt criterion.
Request for Confirmation of Information, RCI-01 The proposed revision to Note 1 of Table 3-2 in DPC-NE-1007-P, Rev. 1, states that the assembly power distribution criterion is not considered failed unless ((
)) exceed the +/-10 percent limit. Please confirm that in the latter case, the criterion would be considered failed if the limit is exceeded in different core locations in each power distribution measurement.