RS-23-038, Response to Request for Additional Information for the Byron Proposal to Reinsert an Accident Tolerant Fuel Lead Test Assembly

Response to Request for Additional Information for the Byron Proposal to Reinsert an Accident Tolerant Fuel Lead Test Assembly

ML23058A147
Person / Time
Site:	Byron
Issue date:	02/27/2023
From:	Lueshen K Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML23058A146	List: RS-23-038, Response to Request for Additional Information for the Byron Proposal to Reinsert an Accident Tolerant Fuel Lead Test Assembly
References
RS-23-038, EPID L-2022-LLA-0131
Download: ML23058A147 (1)

Text

4300 Winfield Road Warrenville, IL 60555 630 657 2000 Office WITHHOLD FROM DISCLOSURE IN ACCORDANCE WITH 10 CFR 2.390 RS-23-038 10 CFR 50.90 February 27, 2023 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Byron Station, Unit 2 Renewed Facility Operating License No. NPF-66 NRC Docket No. STN 50-455

Subject:

Response to Request for Additional Information for the Byron Proposal to Reinsert an Accident Tolerant Fuel Lead Test Assembly

References:

1. Letter from K. Lueshen (Constellation Energy Generation, LLC) to U.S. NRC, License Amendment Request to Reinsert an Accident Tolerant Fuel Lead Test Assembly, dated August 31, 2022 (ADAMS Accession No. ML22243A094)

2. Email from J. Wiebe (U.S. NRC) to R.L. Steinman (Constellation Energy Generation, LLC),

Subject:

Preliminary RAIs Related to L-2022-LLA-0131 -

Byron, Unit 2, Reinsertion of an Accident Tolerant Fuel Lead Test Assembly, dated January 20, 2023 In Reference 1, Constellation Energy Generation, LLC (CEG) submitted an amendment request to revise language in Technical Specification 2.1.1, "Reactor Core SLs," and 4.2.1, "Fuel Assemblies," to allow a previously irradiated Accident Tolerant Fuel (ATF) Lead Test Assembly (LTA) to be further irradiated during Byron Station Unit 2, Cycle 25.

In Reference 2, the NRC requested additional information that is needed to complete review of the proposed relief request. Attachment 3 to this letter provides the additional information requested. Attachment 1 is a non-proprietary version of Attachment 3 where the proprietary information has been redacted. contains information proprietary to Westinghouse, and is supported by an Affidavit signed by Westinghouse, the owner of the information. The Affidavit, found in Attachment 2, sets forth the basis on which the information may be withheld from public disclosure by the Nuclear Regulatory Commission (NRC) and addresses with specificity the considerations listed Attachment 3 contains Proprietary Information. Withhold from public disclosure under 10 CFR 2.390. When separated from Attachment 3 this document is decontrolled.

February 27, 2023 U.S. Nuclear Regulatory Commission Page 2 in paragraph (b)(4) of Section 2.390 of the Commissions regulations. Accordingly, it is respectfully requested that the information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR Section 2.390 of the Commissions regulations.

Correspondence with respect to the copyright or proprietary aspects or the supporting Westinghouse Affidavit should reference CAW-23-003 and should be addressed to Camille T.

Zozula, Manager, Regulatory Compliance & Corporate Licensing.

CEG has reviewed the information supporting a finding of no significant hazards consideration, and the environmental consideration, that were previously provided to the NRC in Reference 1.

The additional information provided in this submittal does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration. In addition, the information provided in this submittal does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendment.

CEG is notifying the State of Illinois of this response related to a previous application for a change to the Technical Specifications by sending a copy of this letter and its attachments to the designated State Official in accordance with 10 CFR 50.91, "Notice for public comment; State consultation," paragraph (b).

There are no regulatory commitments contained in this letter. Should you have any questions concerning this letter, please contact Ms. Rebecca L. Steinman at (630) 657-2831.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 27th day of February 2023.

Respectfully, Digitally signed by Lueshen, Kevin Lueshen, Kevin Date: 2023.02.27 09:41:18

-06'00' Kevin Lueshen Sr. Manager Licensing Constellation Energy Generation, LLC Attachments 1 Response to Request for Additional Information (Non-Proprietary Version) 2 Westinghouse Electric Company 10 CFR 2.390 Affidavit 3 Response to Request for Additional Information (Proprietary Version) cc: NRC Regional Administrator, Region III NRC Senior Resident Inspector, Byron Station Illinois Emergency Management Agency - Division of Nuclear Safety

RS-23-038 ATTACHMENT 1 BYRON STATION, UNIT 2 Docket No. STN 50-455 Renewed Facility Operating License No. NPF-66 Response to Request for Additional Information (Non-Proprietary Version)

RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version)

REQUEST FOR ADDITIONAL INFORMATION RELATED TO CHANGES TO TECHNICAL SPECIFICATIONS 2.1.1 AND 4.2.1 TO ALLOW A PREVIOUSLY IRRADIATED ATF LTA TO BE FURTHER IRRADIATED AT BYRON STATION, UNIT 2, DURING CYCLE 25 DOCKET NO. 50-455 EPID: L-2022-LLA-0131 INTRODUCTION By letter dated August 31, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22242A094), Constellation Energy Generation, LLC, (CEG, the licensee) submitted a license amendment request (LAR) to request revisions to Technical Specification 2.1.1, "Reactor Core SLs," and 4.2.1, "Fuel Assemblies," to allow a previously irradiated Accident Tolerant Fuel (ATF) Lead Test Assembly (LTA) to be further irradiated during Byron Station Unit 2, Cycle 25. Byron Station plans to reinsert a previously irradiated LTA containing test rods with Westinghouse ADOPTTM fuel pellets and chromium-coated cladding in Unit 2 during the Fall 2023 refueling outage. The subject LTA would remain in the Unit 2 core for one additional cycle, i.e., Cycle 25; and will then be discharged during the Spring 2025 refueling outage.

After reviewing the LAR (Reference 1), the NRC staff has developed the following requests for additional information (RAIs).

REGULATORY BASES AND RAIs SNSB RAI 1:

REGULATORY BASIS:

10 CFR 50.67 which establishes radiation dose limits for individuals at the boundary of the exclusion area and at the outer boundary of the low population zone.

RAI:

In section 3.4 of attachment 6 to the LAR, the licensee indicates that, for the Condition III and IV accident analysis performed using the current approved methods for Cycle 25, fuel rods in the reinserted LTA are not predicted to fail. The licensee states that this was confirmed for the locked rotor and rod ejection analysis.

Please provide a discussion on the analysis methodology and the results from evaluations performed for the limiting case(s) to show that high burnup ATF LTA does not experience DNBR or exceed other applicable fuel integrity acceptance criteria during:

a) the locked rotor event &

b) the rod ejection event.

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RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version)

CONSTELLATION RESPONSE TO SNSB RAI 1:

a) Locked Rotor:

The Lead Test Assembly (LTA) evaluation is based on the existing method in the Byron Updated Final Safety Analysis Report (UFSAR). [

]a,c b) Rod Ejection:

[

]a,c 2 of 11

RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version)

[

]a,c 3 of 11

RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version)

SNSB RAI 2:

REGULATORY BASIS:

10 CFR 50.46(b)(4), Coolable geometry, which states Calculated changes in core geometry shall be such that the core remains amenable to cooling.

RAI:

In section 3.4 of attachment 6 to the LAR, the licensee states that the LTA will have a significant reduction of power and peaking factors relative to the core lead such that the LTA being reinserted for higher burnup does not pose any additional fuel dispersal risk. The licensee further states in section 4.1 of the attachment 6 to the LAR that no cladding rupture has been demonstrated for the LTA, which would preclude concerns associated with fuel dispersal under high burnup conditions. During an audit conducted over December 12-16, 2022, the licensee discussed further information supporting these statements in its LAR.

To demonstrate no cladding rupture and preclude any concerns associated with fuel dispersal, drawing as necessary upon materials discussed during the audit, please provide the following:

(a) A comparison of rod internal pressures at the proposed higher burnups for the ATF LTA to a comparable standard reload fuel assembly, along with brief discussion of the methodology behind the comparison.

(b) An evaluation of margin to rupture for the limiting LTA rod for the LOCA event along with an assessment of the effect of significant factors that would influence the margin to rupture at the proposed higher burnups for the LTA. Please consider the following specific questions in addressing the available margin:

i. A quantification of the margin to rupture for the [

] of the LTA proposed for reinsertion during Cycle 25.

ii. A comparison of the limiting fuel rod for the LTA proposed for reinsertion [

]. The NRC staff observes that there are multiple differences [ ] that were not directly included in the analysis that could affect the propensity for rupture, including at least the following: (1) a difference in linear power density, (2) a burnup-driven difference in rod internal pressure, and (3) a burnup-driven difference in fuel stored energy.

Please clarify the magnitude of the differences with respect to these factors, and any other key factors identified by the licensee, along with their expected net impact on the limiting cladding rupture margin for the LTA.

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RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version)

CONSTELLATION RESPONSE TO SNSB RAI 2:

1.0 Characterization of Proposed Higher Burnup LTA Conditions The lead test assembly (LTA) will be reinserted in the center core assembly, underneath a guide tube (GT) structure, and will be operated at a lower power and peaking factors than the core lead rod (Figure RAI 2-1). Given the significant difference in the power between the LTA and the lead rod from the FULL SPECTRUM' Loss of Coolant Accident (FSLOCATM) Evaluation Method (EM) Analysis of Record (AOR) (Reference 2), the core lead rod is not well representative of the LTA conditions at high burnup. The [

]a,c 1.1 Nuclear Design The LTA Average Linear Heat Rate (ALHR) varies between [ ]a,c a,c throughout the cycle, reaching the [ ] Similarly, the LTA Peak Linear Heat Rate (PLHR) varies between [ ]a,c throughout the cycle, reaching the [ ]a,c Finally, the burnup of the LTA (more specifically the lead rod in the LTA) ranges from [

]a,c

[

]a,c 1.2 Fuel Rod Design The differences between the LTA and [ ]a,c in power and burnup established in Section 1.1 lead to differences in the fuel rod initial conditions. As noted in the RAI, the rod internal pressure (RIP) and fuel rod stored energy are of particular interest when demonstrating margin to rupture.

1.2.1 Impact on Rod Internal Pressure The RIP range from the AOR fuel performance data is compared to the RIP range from the LTA fuel performance data. This comparison is made at [

]a,c Since RIP tends to increase with burnup and ALHR, using a [ ]a,c ADOPT, FULL SPECTRUM, and FSLOCA are trademarks or registered trademarks of Westinghouse Electric Company LLC, its affiliates and/or its subsidiaries in the United States of America and may be registered in other countries throughout the world. All rights reserved. Unauthorized use is strictly prohibited. Other names may be trademarks of their respective owners.

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RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version)

[ ]a,c than those determined in Section 1.1 will tend to be slightly conservative. As the LTA rods contains both UO2 and ADOPT pellets, the

[ ]a,c Figure RAI 2-2 shows LTA and AOR rod internal pressure ranges as function of burnup. The RIP range of the LTA fuel and the AOR fuel are similar up to the 62 GWd/MTU. As the LTA continues to accrue burnup, the predicted RIP continues to increase. At end-of-life, the LTA RIP range is [ ]a,c than the AOR RIP range.

Since higher RIP increases the potential for burst, this detrimental effect is considered in the margin to rupture quantification in Section 2.0. To account for the [

]a,c 1.2.2 Impact on Fuel Stored Energy The fuel average temperature from the AOR fuel performance data are compared to those for the LTA rods. The comparison is performed at the PLHRs established in Section 1.1.

Figure RAI 2-3 shows that the fuel average temperatures are [

]a,c compared to the LTA rod. When comparing the fuel temperatures at the [

]a,c Since lower stored energy decreases the potential for burst, this beneficial effect is not considered in the margin to rupture quantification, while recognizing that the fuel stored energy will have a first order effect on the calculated cladding temperature.

2.0 Evaluation of the Margin to Cladding Rupture for the Limiting LTA Rod An assessment of the margin to rupture for the limiting LTA rod for the LOCA event is performed to demonstrate that fuel dispersal from the high burnup LTA will not occur. The fuel rod rupture model in the FSLOCA EM is a function of [

]a,c 6 of 11

RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version)

[

]a,c 3.0 Summary A[ ]a,c to demonstrate that the rods in the LTA will not rupture under postulated LOCA conditions was performed. Information [

]a,c 7 of 11

RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version)

Table RAI 2 Margin to Cladding Rupture Results a,c 8 of 11

RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version) a,c Figure RAI 2 Comparison of FH and FQ for Cycle 25 LTA U72Y 9 of 11

RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version) a,c Figure RAI 2 Rod Internal Pressure Comparison 10 of 11

RS-23-038 ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version) a,c Figure RAI 2 Fuel Average Temperature Nuclear Design REFERENCES

1. Letter from Constellation Energy Generation, LLC, (CEG) to NRC, dated August 31, 2022, License Amendment Request for Changes to Technical Specification 2.1.1 and 4.2.1 To Reinsert an Accident Tolerant Fuel Lead Test Assembly at Byron Station Unit 2 (ADAMS Accession No. ML22242A094)

2. Letter from J. S. Wiebe (U.S. NRC) to B. C. Hanson (Exelon Generation Company, LLC),

Braidwood Station, Units 1 and 2, and Byron Station, Unit Nos. 1 and 2 - Issuance of Amendment Nos. 219, 219, 223, and 223 Regarding Revision of Technical Specifications 5.6.5, Core Operating Limits Report (COLR) (EPID L-2020-LLA-0038),

December 2020 (U.S. NRC Agencywide Documents Access and Management System (ADAMS) Accession No. ML20317A001).

3. WCAP-16996-P-A, Revision 1, Realistic LOCA Evaluation Methodology Applied to the Full Spectrum of Break Sizes (FULL SPECTRUM LOCA Methodology), November 2016.

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RS-23-038 ATTACHMENT 2 BYRON STATION, UNIT 2 Docket No. STN 50-455 Renewed Facility Operating License No. NPF-66 Westinghouse Electric Company 10 CFR 2.390 Affidavit

Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-23-003 Page 1 of 3 Commonwealth of Pennsylvania:

County of Butler:

(1) I, Zachary Harper, Manager, Licensing Engineering, have been specifically delegated and authorized to apply for withholding and execute this Affidavit on behalf of Westinghouse Electric Company LLC (Westinghouse).

(2) I am requesting the proprietary portions of Attachment 3 to RS-23-038 be withheld from public disclosure under 10 CFR 2.390.

(3) I have personal knowledge of the criteria and procedures utilized by Westinghouse in designating information as a trade secret, privileged, or as confidential commercial or financial information.

(4) Pursuant to 10 CFR 2.390, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.

(i) The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse and is not customarily disclosed to the public.

(ii) The information sought to be withheld is being transmitted to the Commission in confidence and, to Westinghouses knowledge, is not available in public sources.

(iii) Westinghouse notes that a showing of substantial harm is no longer an applicable criterion for analyzing whether a document should be withheld from public disclosure. Nevertheless, public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar technical evaluation justifications and licensing defense services for commercial power reactors without commensurate expenses. Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.

Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-23-003 Page 2 of 3 (5) Westinghouse has policies in place to identify proprietary information. Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows:

(a) The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any of Westinghouse's competitors without license from Westinghouse constitutes a competitive economic advantage over other companies.

(b) It consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage (e.g., by optimization or improved marketability).

(c) Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar product.

(d) It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or suppliers.

(e) It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercial value to Westinghouse.

(f) It contains patentable ideas, for which patent protection may be desirable.

(6) The attached documents are bracketed and marked to indicate the bases for withholding. The justification for withholding is indicated in both versions by means of lower-case letters (a) through (f) located as a superscript immediately following the brackets enclosing each item of information being identified as proprietary or in the margin opposite such information. These lower-case letters refer to the types of information Westinghouse customarily holds in confidence identified in Sections (5)(a) through (f) of this Affidavit.

Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-23-003 Page 3 of 3 I declare that the averments of fact set forth in this Affidavit are true and correct to the best of my knowledge, information, and belief. I declare under penalty of perjury that the foregoing is true and correct.

Executed on: 2/23/2023 _____________________________

Signed electronically by Zachary Harper