Daily Rules, Proposed Rules, and Notices of the Federal Government
Dominion Nuclear Connecticut, Inc., (the licensee, Dominion) is the holder of Renewed Facility Operating License No. NPF-49, which authorizes operation of the Millstone Power Station, Unit 3 (MPS3). The license provides, among other things, that the facility is subject to all rules, regulations, and orders of the Nuclear Regulatory Commission (NRC, the Commission) now or hereafter in effect.
MPS3 shares the site with Millstone Power Station Unit 1, a permanently defueled boiling water reactor nuclear unit, and Millstone Power Station Unit 2, a pressurized water reactor. The facility is located in Waterford, Connecticut, approximately 3.2 miles west southwest of New London, CT. This exemption applies to MPS3 only. The other units, Units 1 and 2, are not part of this exemption.
Section 50.46 of Title 10 of the
Both of the above requirements require the use of zircaloy or ZIRLO
In summary, by letter dated November 17, 2011, (Agencywide Documents Access and Management System (ADAMS), Accession No. ML11329A003), the licensee requested an exemption from the requirements of 10 CFR 50.46 and Appendix K to 10 CFR part 50. The reason for the exemption is to allow the use of Optimized ZIRLO
Pursuant to 10 CFR 50.12, the Commission may, upon application by any interested person or upon its own initiative, grant exemptions from the requirements of 10 CFR part 50 when (1) the exemptions are authorized by law, will not present an undue risk to public health or safety, and are consistent with the common defense and security; and (2) when special circumstances are present. These circumstances include the special circumstances that application of the regulation is not necessary to achieve the underlying purpose of the rule.
This exemption would allow the licensee to use Optimized ZIRLO
The underlying purpose of 10 CFR 50.46 is to establish acceptance criteria for adequate ECCS performance. By letter dated June 10, 2005 (ADAMS Accession No. ML051670408), the NRC staff issued a safety evaluation (SE) approving Addendum 1 to Westinghouse Topical Report WCAP-12610-P-A and CENPD-404-P-A, "Optimized ZIRLO
The underlying purpose of 10 CFR Part 50, Appendix K, Section I.A.5, "Metal-Water Reaction Rate," is to ensure that cladding oxidation and hydrogen generation are appropriately limited during a LOCA and conservatively accounted for in the ECCS evaluation model. Appendix K states that the rates of energy release, hydrogen concentration, and cladding oxidation from the metal-water reaction shall be calculated using the Baker-Just equation. Since the Baker-Just equation presumes the use of zircaloy clad fuel, strict application of the rule would not permit use of the equation for Optimized ZIRLO
Based on the above, no new accident precursors are created by using Optimized ZIRLO
The proposed exemption would allow the use of Optimized ZIRLO
Special circumstances, in accordance with 10 CFR 50.12(a)(2)(ii), are present whenever application of the regulation in the particular circumstances is not necessary to achieve the underlying purpose of the rule. The underlying purpose of 10 CFR 50.46 and Appendix K to 10 CFR part 50 is to establish acceptance criteria for ECCS performance and to ensure that cladding oxidation and hydrogen generation are appropriately limited during a LOCA and conservatively accounted for in the ECCS evaluation model. The wording of the regulations in 10 CFR 50.46 and Appendix K is not directly applicable to Optimized ZIRLO
Accordingly, the Commission has determined that, pursuant to 10 CFR 50.12, the exemption is authorized by law, will not present an undue risk to the public health and safety, and is consistent with the common defense and security. Also, special circumstances are present. Therefore, the Commission hereby grants Dominion an exemption from certain requirements of 10 CFR 50.46 and Appendix K to 10 CFR part 50, to allow the use of Optimized ZIRLO
Pursuant to 10 CFR 51.32, the Commission has determined that the granting of this exemption will not have a significant effect on the quality of the human environment (77 FR 50533).
This exemption is effective upon issuance.