Tennessee Valley Authority; Sequoyah Nuclear Plant Independent Spent Fuel Storage Installation; Exemption

SUPPLEMENTARY INFORMATION:

I. Discussion

The NRC issued an exemption to TVA for the SQN ISFSI. By letter dated August 4, 2022, as supplemented by letters dated December 19, 2022, April 27, 2023, and January 3, 2024, TVA submitted to the NRC an exemption request for the SQN ISFSI, in accordance with section 72.7 of title 10 of the Code of Federal Regulations (10 CFR), “Specific exemptions,” from the requirements of 10 CFR 72.212(a)(2), 72.212(b)(3), 72.212(b)(5)(i), 72.212(b)(11), 72.214, 72.154(b), and 72.174. Specifically, the exemption request permits SQN ISFSI to deviate from conditions of the NRC CoC No. 1032, Amendment No. 3, appendix B, section 3.3, “Codes and Standards.”

The requirements contained in 10 CFR 72.212(a)(2), 72.212(b)(3), 72.212(b)(5)(i), 72.212(b)(11), 72.214, 72.154(b), and 72.174 are applicable to CoC No. 1032, which was issued to Holtec. The condition of CoC No.1032, appendix B, technical specifications, section 3.3, “Codes and Standards,” specifies American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code, 2007 Edition, as the governing B&PV Code for Holtec's HI-STORM Flood/Wind (FW) Multi-Purpose Canister (MPC) Storage System, the dry cask spent fuel storage system in use at SQN ISFSI. The ASME B&PV Code requires that 100 percent of the weld seam joining shell-to-shell of the MPC be inspected by radiography test (RT) where RT is a form of non-destructive examination.

The licensee loaded spent fuel in the HI-STORM FW dry cask storage system MPC Type 37 (MPC-37), Serial No. 234, for storage in the ISFSI at SQN under CoC No. 1032, Amendment No. 3, and its general license. During a review of manufacturer's documents, the CoC holder identified that MPC-37 Serial No. 234 at SQN ISFSI has a longitudinal shell-to-shell weld for which no digital RT is available following a weld repair, which is inconsistent with the governing ASME B&PV code for this CoC system. When TVA was notified of this issue, MPC-37 Serial No. 234 was already put in use, and TVA registered it by letter dated February 24, 2022, entitled “Sequoyah Nuclear Plant Registration of Spent Fuel Storage Cask Pursuant to 10 CFR 72.212(b)(2).” TVA then submitted this exemption request to the NRC to allow continued storage of spent fuel in MPC-37 Serial No. 234 for the service life of the canister at SQN, despite the non-compliance with the ASME B&PV code.

Based on the NRC staff's review of TVA's analysis supporting the exemption request, the NRC staff determined that, pursuant to 10 CFR 72.7, the exemption is authorized by law, will not endanger life or property or the common defense and security, and is otherwise in the public interest. Therefore, the NRC granted the licensee an exemption from the requirements of 10 CFR 72.212(a)(2), 10 CFR 72.212(b)(3), 10 CFR 72.212(b)(5)(i), 10 CFR 72.212(b)(11), 10 CFR 72.214, 10 CFR 72.154(b), and 10 CFR 72.174 with regard to: (1) meeting the requirement to repeat volumetric examination as required for the original weld on an approximately 7.5-inch portion of the repaired weld in conformance with section III, subsection NB, of the ASME B&PV Code, 2007 Edition, and (2) maintaining and having available documentary evidence of the test for the service life of the canister. The exemption allowed TVA to continue using MPC-37 Serial No. 234 to store spent fuel for the service life of the canister at SQN. All other relevant requirements of the CoC shall continue to be met. This exemption, including the supporting evaluation for issuance of it, can be found in the table as follows.

II. Availability of Documents

The documents identified in the following table are available to interested persons through one or more of the following methods, as indicated.