ML18164A319
| ML18164A319 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 06/18/2018 |
| From: | Natreon Jordan Plant Licensing Branch II |
| To: | James Shea, Skaggs M Tennessee Valley Authority |
| Jordan N, 415-7410 | |
| References | |
| Download: ML18164A319 (16) | |
Text
Watts Bar Nuclear Plant Pre-Submittal Teleconference for Proposed License Amendment Request Regarding Application to Revise Watts Bar Nuclear Plant Units 1 and 2 Technical Specifications and 10 CFR 50.12 Exemption Request to Implement Optimized ZIRLO' Fuel Rod Cladding June 19, 2018
Agenda
- Opening Remarks and Purpose of the Proposed License Amendment Request (LAR) and Exemption Request
- Proposed Technical Specification Changes
- Technical Analysis of the Proposed LAR and Exemption Request
- Regulatory Precedent
- Schedule for Submittal
- Summary and Closing Remarks l 2
Opening Remarks and Purpose of the Proposed LAR and Exemption Request
- The proposed Technical Specification (TS) amendment revises the WBN Units 1 and 2 TS 4.2.1, Fuel Assemblies, and 5.9.5, Core Operating Limits Report (COLR), to allow the use of Optimized ZIRLO'1 as an approved fuel rod cladding material.
- The license amendment request (LAR) is consistent with the Nuclear Regulatory Commission (NRC) safety evaluation that approved the use of Optimized ZIRLO fuel rod cladding material as documented in WCAP-12610-P-A and CENPD-404-P-A, Addendum 1-A (Proprietary) and WCAP-14342-A and CENPD-404-NP-A (Non-Proprietary).
- In support of this LAR, an exemption request is also being submitted in accordance with 10 CFR 50.12, "Specific exemptions, from certain requirements of 10 CFR 50.46, "Acceptance criteria for emergency core cooling systems for light-water nuclear power reactors," and 10 CFR 50, Appendix K, "ECCS Evaluation Models."
Proposed WBN 1 & 2 TS 4.2.1 Changes l 4
Proposed WBN 1 & 2 TS 5.9.5 Changes l 5
Technical Analysis of the Proposed LAR
- Optimized ZIRLO was developed to meet the needs of longer operating cycles with increased fuel discharge burnup and fuel duty.
- Compared to ZIRLO2, the lower tin content and microstructure difference of Optimized ZIRLO provides a reduced corrosion rate while maintaining the benefits of mechanical strength and resistance to accelerated corrosion from abnormal chemistry conditions.
- Optimized ZIRLO scheduled to be loaded in the WBN Unit 2 Fall 2020 Refueling Outage (U2R3) and the WBN Unit 1 Fall 2021 Refueling Outage (U1R17).
Technical Analysis of the Proposed LAR
- Optimized ZIRLO evaluated and approved by the NRC in their Safety Evaluation (SE) (ML051670403) for WCAP-12610-P-A and CENPD-404-P-A, Addendum 1-A .
- The LAR (Enclosure 1 to the submittal) addresses each of the 10 conditions in the NRC SE. Exceptions are:
- NRC Condition 8b, WBN uses a Westinghouse fuel design and not a CE fuel design; therefore, Condition 8.b does not apply.
- NRC Condition 9, WBN is not licensed to use the LOCBART or STRIKIN-11 codes.
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Technical Analysis of the Proposed LAR
- TVA submitted a LAR to NRC on 3/5/18 (ML18064A192) for WBN Unit 2 to permit continued use of the PAD4TCD computer program to continue to establish core operating limits until the WBN Unit 2 steam generators (SGs) are replaced.
- TVA submitted a LAR to NRC on 12/20/17 (ML17354B282) to authorize the use of TPBARs in the WBN Unit 2 reactor core.
- The use of Optimized ZIRLO is bounded by the analyses that support these licensing actions.
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- The 10 CFR 50.46 and 10 CFR 50, Appendix K regulations are currently limited in applicability to the use of fuel rods with zircaloy or ZIRLO cladding. 10 CFR 50.46 and 10 CFR 50, Appendix K do not apply to the proposed use of Optimized ZIRLO fuel rod cladding material because Optimized ZIRLO has a slightly different composition than zircaloy or ZIRLO.
- Pursuant to 10 CFR 50.12, the requested exemption is authorized by law, does not present undue risk to public health and safety, and is consistent with the common defense and security. Approval of this exemption request does not violate the underlying purpose of the rule. In addition, special circumstances exist to justify the approval of an exemption from the subject requirements.
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- The exemption request addresses Criteria 1 and 2 of 10 CFR 50.12, "Specific exemptions.
- Criterion 1
- This exemption is authorized by law.
- This exemption will not present an undue risk to public health and safety.
- This exemption is consistent with the common defense and security.
- Criterion 2 - Special circumstances support the issuance of an exemption.
- 10 CFR 50.12(a)(2)(ii), "Application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule.
- For WBN, application of the subject regulations is not necessary to achieve the underlying purpose of the rule.
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Technical Analysis of the Exemption Request
- The exemption request (Enclosure 2 to the submittal) regards the provisions of 10 CFR 50.46, and 10 CFR 50, Appendix K.
- 10 CFR 50.46 contains acceptance criteria for the emergency core cooling system (ECCS) for reactors that have fuel rods fabricated either with zircaloy or ZIRLO fuel rod cladding material.
- Concurrently, 10 CFR 50, Appendix K.I.A.5, requires the Baker-Just equation be used to calculate the rate of energy release, hydrogen generation, and cladding oxidation from the metal-water reaction in the core. The Baker-Just equation assumes the use of a zirconium alloy other than Optimized ZIRLO' material.
- The exemption request relates solely to the specific cladding material identified in the above regulations (fuel rods with zircaloy or ZIRLO cladding) and will provide for the application of 10 CFR 50.46 and 10 CFR 50, Appendix K acceptance criteria to fuel assembly designs utilizing Optimized ZIRLO fuel rod cladding at WBN Units 1 and 2.
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Technical Analysis of the Exemption Request Supporting information for the Exemption Request includes:
- Compliance with the conditions in the NRC SE for WCAP-12610-P-A and CENPD-404-P-A, Addendum 1-A.
- Future reload evaluations will ensure that acceptance criteria are met for the insertion of fuel assemblies composed of fuel rods clad with Optimized ZIRLO These fuel assemblies will be evaluated using NRC-approved methods and models.
- Application of the Baker-Just equation has been demonstrated to be appropriate for Optimized ZIRLO. Due to the similarities in material composition of the Optimized ZIRLO and ZIRLO fuel rod cladding, the application of the Baker-Just equation will continue to conservatively bound all post-LOCA scenarios.
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Regulatory Precedent
- This LAR and exemption request are similar in nature to the following LARs and exemption requests approved by the NRC that authorized the use of Optimized ZIRLO fuel rod cladding:
- Beaver Valley Power Station, Unit Nos. 1 and 2 (ML18022B116 and ML17313A550 dated 3/1/18)
- Palo Verde Nuclear Generating Station, Units 1, 2, and 3 (ML17319A207 and ML17319A103 dated 1/23/18)
- R.E. Ginna Nuclear Power Plant (ML17131A066 and ML17131A113 dated 6/21/17)
- Wolf Creek Generating Station (ML16179A293 and ML16179A440 dated 8/2/16)
- Seabrook Station, Unit No. 1 (ML13213A143 and ML13213A074 dated 3/5/14)
- RAIs associated with the above submittals (as applicable) were reviewed l 13
Schedule for Submittal
- June 19, 2018 - Pre-submittal teleconference with NRC
- August 3, 2018 - Submit LAR to NRC
- Request NRC approval within one year from the date of submittal with a 30-day implementation date
- Supports schedule for planning activities for the U2R3 Refueling Outage and the U1R17 Refueling Outage.
- September 2018 - Telecon or meeting to discuss any NRC questions (if needed) l 14
Closing Remarks
- Proposed LAR and exemption request will allow the use of Optimized ZIRLO as an approved fuel rod cladding material.
- Proposed LAR and exemption request provides reasonable assurance that the health and safety of the public will not be endangered.
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