04-1944. Maine Yankee Atomic Power Company Independent Spent Fuel Storage Installation Issuance of Environmental Assessment and Finding of No Significant Impact for a Proposed Exemption

The U.S. Nuclear Regulatory Commission (NRC or Commission) is considering issuance of an exemption to Maine Yankee Atomic Power Company (MYAPC or licensee), pursuant to 10 CFR 72.7, from specific provisions of 10 CFR 72.212(a)(2), 72.212(b)(2)(i), 72.212(b)(7), and 72.214. The licensee is using the NAC-UMS Storage System to store spent nuclear fuel from the decommissioning reactor at an Independent Spent Fuel Storage Installation (ISFSI). The requested exemption would allow MYAPC to deviate from requirements of the NAC-UMS Certificate of Compliance No. 1015 (CoC or Certificate), Amendment 2, Appendix B, Section B 3.4.2.6. Specifically, the exemption would relieve MYAPC from the requirement to maintain a coefficient of friction between the vertical concrete cask and ISFSI pad surface of at least 0.5.

Environmental Assessment (EA)

Identification of Proposed Action

By letter dated October 2, 2003, as supplemented on October 21, 2003, MYAPC requested an exemption from the requirements of 10 CFR 72.212(a), 72.212(b)(2)(i), 72.212(b)(7), and 10 CFR 72.214 to deviate from the requirements in CoC No. 1015, Amendment 2, Appendix B, Section B 3.4.2.6. MYAPC is storing spent nuclear fuel under the general licensing provisions of 10 CFR part 72 in the NAC-UMS Storage System at an ISFSI located at the Maine Yankee Atomic Power Station in Wiscasset, Maine. The licensee is loading additional spent fuel into storage at the ISFSI.

The current requirements in CoC No. 1015, Amendment 2, Appendix B, state that physical testing shall be conducted to demonstrate that the coefficient of friction between the vertical concrete cask and ISFSI pad surface is at least 0.5.

By exempting MYAPC from specific provisions of 10 CFR 72.212(a)(2), 72.212(b)(2)(i), 72.212(b)(7), and 10 CFR 72.214 for this request, MYAPC will not be required to maintain a coefficient of friction between the vertical concrete cask and ISFSI pad surface of at least 0.5.

The proposed action before the Commission is whether to grant this exemption under the provisions of 10 CFR 72.7. The NRC staff has reviewed the exemption request and determined that not maintaining a coefficient of friction between the vertical concrete cask and the ISFSI pad surface of at least 0.5, is consistent with the safety analyses previously reviewed for the NAC-UMS system, and would have no impact on the design basis and would not be inimical to public health and safety.

Need for the Proposed Action

During the 2002-2003 winter, MYAPC discovered a condition in which the surface area between the vertical concrete casks and the ISFSI pad had a significant covering of ice (approximately 80-95 percent of the surface). This winter icing condition may result in a reduced coefficient of friction that does not meet the requirements of CoC No. 1015, Amendment 2, Section B 3.4.2.6, for a coefficient of friction of at least 0.5 between the vertical concrete casks and the ISFSI pad surface. The icing condition was unanticipated and therefore not explicitly addressed in the cask licensing basis. The presence of ice causes a loss of contact between the vertical concrete casks and the ISFSI pad and leads to an indeterminate coefficient of friction. Since the icing condition renders previous test results insufficient to demonstrate a coefficient of friction greater than 0.5, MYAPC would not be in compliance with the CoC during these icing conditions.

Granting the requested exemption will allow MYAPC to regain compliance with CoC No. 1015, Amendment 2, in a timely manner. Section B 3.4.2.6 is a requirement specific to MYAPC and applicable to no other licensees.

Environmental Impacts of the Proposed Action

The licensee requested the exemption from maintaining a coefficient of friction between the vertical concrete cask and the ISFSI pad surface of at least 0.5 as specified in CoC No. 1015, Amendment 2. The NRC staff performed a safety evaluation of the proposed exemption. Staff reviewed the analysis provided by MYAPC in the exemption request for winter icing conditions which may result in a reduced coefficient of friction between the vertical concrete cask and the ISFSI pad surface, and limited vertical concrete cask sliding during a design earthquake. Staff judged that the design earthquake will not cause large sliding of the NAC-UMS vertical concrete cask on the ISFSI pad surfaces. In the unlikely event of vertical concrete cask impacts, staff evaluated the magnitude of the impact load between two colliding casks and determined the impact load would be far less severe than that encountered in a tip-over accident for which the NAC-UMS system has been demonstrated structurally adequate. The staff concludes that the NRC has reasonable assurance that the proposed exemption has no impact on off-site doses, and is acceptable.

Therefore, the environmental impact of not maintaining a coefficient of friction between the vertical concrete cask and the ISFSI pad surface of at least 0.5, is no greater than the environmental impact already assessed in the initial rulemaking for the NAC-UMS storage system (65 FR 62581, dated October 19, 2000).

The proposed action will not increase the probability or consequences of the analyzed accidents, no changes are being made to the types of effluents that may be released offsite, and there is no increase in occupational or public radiation exposure. Therefore, there are no significant radiological environmental impacts associated with the proposed action. Therefore, the staff has determined that there is no reduction in the ability of the NAC-UMS system to perform its safety function, nor significant environmental impacts, as a result of not maintaining a coefficient of friction between the vertical concrete cask and the ISFSI pad surface of at least 0.5.

Alternative to the Proposed Action

Since there is no significant environment impact associated with the proposed action, alternatives with equal or greater environmental impact are not evaluated. The alternative to the proposed action would be to deny approval of the exemption. Denial of the exemption request will have the same environmental impact.

Agencies and Persons Consulted

This exemption request was discussed with Mr. Charles Pray, State Nuclear Safety Advisor for the State of Maine, on January 6, 2004, and he stated that the State had no comments on the technical aspects of the exemption. The NRC staff has determined that a consultation under Section 7 of the Endangered Species Act is not required because the proposed action will not affect listed species or critical habitat. The NRC staff has also determined that the proposed action is not a type of activity having the potential to cause effects on historic properties. Therefore, no further consultation is required under Section 106 of the National Historic Preservation Act.

Finding of No Significant Impact

The environmental impacts of the proposed action have been reviewed in accordance with the requirements set forth in 10 CFR Part 51. Based upon the foregoing EA, the Commission finds that the proposed action of granting the exemption from specific provisions of 10 CFR 72.212(a), 72.212(b)(2)(i), 72.212 (b)(7), and 10 CFR 72.214, and not requiring MYAPC to maintain a coefficient of friction between the concrete cask and ISFSI pad surface of at least 0.5, will not significantly impact the quality of the human environment. Accordingly, the Commission has determined that an environmental impact statement for the proposed exemption is not warranted.

The request for exemption was docketed under 10 CFR part 72, Docket 72-30. For further details with respect to this action, see the exemption request dated October 2, 2003, as supplemented. The NRC maintains an Agencywide Documents Access and Management System (ADAMS), which provides text and image files of NRC's public documents. These documents may be accessed through the NRC's Public Electronic Reading Room on the Internet at http://www.nrc.gov/​reading-rm/​adams.html. If you do not have access to ADAMS or if there are problems in accessing the documents located in ADAMS, contact the NRC Public Document Room Reference staff at 1-800-397-4209, 301-415-4737, or by e-mail to [e-mail].

Dated at Rockville, Maryland, this 23rd day of January, 2004.

For the Nuclear Regulatory Commission.

Stephen C. O'Connor, Sr.,

Project Manager, Spent Fuel Project Office, Office of Nuclear Material Safety and Safeguards.