E6-20568. Energy Northwest, Columbia Generating Station Independent Spent Fuel Storage Installation Environmental Assessment and Finding of No Significant Impact Regarding a Proposed Exemption

AGENCY:

Nuclear Regulatory Commission.

ACTION:

Environmental Assessment and Finding of No Significant Impact.

FOR FURTHER INFORMATION CONTACT:

Christopher M. Regan, Senior Project Manager, Division of Spent Fuel Storage and Transportation, Office of Nuclear Material Safety and Safeguards, U.S. Nuclear Regulatory Commission, Washington, DC 20555. Telephone: [phone]; fax number: [phone]; e-mail: [e-mail].

SUPPLEMENTARY INFORMATION:

The U.S. Nuclear Regulatory Commission (NRC or Commission) is considering a request dated September 14, 2006, from Energy Northwest (applicant or Energy Northwest) for an exemption from certain requirements of Title 10, Code of Federal Regulations (CFR), Part 72 (10 CFR part 72), specifically, 10 CFR 72.212(a)(2), 72.212(b)(2)(i)(A), 72.212(b)(7), and 72.214, pursuant to 10 CFR 72.7, for the Columbia Generating Station (CGS) Independent Spent Fuel Storage Installation (ISFSI), located on the CGS site in Benton County, Washington. The CGS ISFSI is an existing facility constructed for interim dry storage of spent nuclear fuel.

At the CGS ISFSI, Energy Northwest has stored spent nuclear fuel in fifteen Holtec International HI-STORM 100 storage casks. As set forth in 10 CFR 72.214, the NRC has approved use of the HI-STORM 100 Cask System in Certificate of Compliance (CoC) 1014. The NRC has issued Amendments 1 (effective date July 15, 2002) and 2 (effective date June 7, 2005) to CoC 1014. Energy Northwest loaded the spent nuclear fuel into the HI-STORM 100 storage casks at the CGS ISFSI under Amendment 1. If approved by the NRC, the exemption would apply to all HI-STORM 100 storage casks fabricated and used in accordance with Amendment 1 of CoC 1014 at the CGS ISFSI.

The exemption would authorize the applicant to perform analyses consistent with that granted by the NRC in Amendment 2 to CoC 1014 in lieu of certain analyses required by Amendment 1 to CoC 1014, specifically, Appendix B, Section 3.4.3.a., Site Specific Parameters and Analyses (concerning the determination of Holtec HI-STORM 100/ISFSI pad interface coefficient of friction under environmental conditions that may degrade the pad/cask interface, such as those caused by icing).

The NRC has prepared an environmental assessment for this proposed action in accordance with the requirements of 10 CFR part 51. Based on the environmental assessment, the NRC has concluded that a Finding of No Significant Impact (FONSI) is appropriate with respect to the proposed action.

Environmental Assessment (EA)

I. Identification of Proposed Action

By letter dated September 14, 2006, Energy Northwest requested an exemption from the requirements of 10 CFR 72.212(a), 72.212(b)(2)(i), 72.212(b)(7) and 72.214, specifically, exemption from complying with Appendix B, Section 3.4.3.a., Site Specific Parameters and Analyses of Amendment 1 to CoC 1014, which requires a determination of the HI-STORM 100/ISFSI pad interface coefficient of friction under environmental conditions that may degrade the pad/cask interface, such as those caused by icing. Approval of the exemption request would allow the applicant to perform an analysis consistent with that granted by the NRC in Amendment 2 to CoC 1014 when evaluating icing conditions between the bottom of the HI-STORM 100 storage casks and the ISFSI pad in lieu of determining the HI-STORM 100/ISFSI interface coefficient of friction. The presence of ice formation at the interface between the bottom of the HI-STORM 100 storage casks and the ISFSI pad can result in the storage system being in an unanalyzed condition. Energy Northwest determined that the HI-STORM 100 storage casks used at the CGS ISFSI were susceptible to the icing phenomena and developed compensatory measures during cold weather conditions to maintain the friction coefficient in accordance with Amendment 1 to CoC 1014.

For the NRC to permit Energy Northwest to demonstrate the safe condition of the HI-STORM 100 storage casks at the CGS ISFSI during cold weather conditions by performing analyses consistent with methods approved in Amendment 2 to CoC 1014, the NRC must grant Energy Northwest an exemption from certain general license conditions defined in 10 CFR 72.212 and the list of approved casks in 10 CFR 72.214. The NRC regulation, 10 CFR 72.212(a)(2), states that the general license for the storage of spent nuclear fuel at power reactor sites is limited to storage in casks approved under the provisions in 10 CFR part 72. By exempting Energy Northwest from 10 CFR 72.214, 10 CFR 72.212(a)(2) and certain other regulations in 10 CFR part 72.212 that concern compliance with the applicable CoC, namely, 72.212(b)(2)(i)(A) and 72.212(b)(7), Energy Northwest will be authorized to deviate from CoC 1014 (Amendment 1) Appendix B, Section 3.4.3.a, which requires determination of the HI-STORM 100/ISFSI pad interface coefficient of friction.

II. Need for the Proposed Action

Fifteen HI-STORM 100 storage casks have been loaded under Amendment 1 of CoC 1014 and are stored at the CGS ISFSI. Energy Northwest is currently performing compensatory measures during cold weather conditions, including monitoring operator walkdowns, de-icing, and clearing of a pathway on the ISFSI for draining, to maintain the friction coefficient in accordance with Amendment 1 to CoC 1014. Elimination of the need to continue implementation of these compensatory measures would reduce worker radiation dose and free operators to be more responsive to other duties.

III. Environmental Impacts of the Proposed Action

The potential environmental impact of using the HI-STORM 100 Cask System was initially analyzed in the environmental assessment for the final rule to add the HI-STORM 100 Cask System to the list of approved spent fuel storage casks in 10 CFR 72.214 (65 FR 25241; May 1, 2000). In addition, the potential environmental impact of Amendment 2 changes to CoC 1014 was analyzed in the environmental assessment for the final rule that amended 10 CFR 72.214 to add Amendment 2 to CoC 1014 (70 FR 32977; June 7, 2005). Both environmental assessments concluded that there would be no significant environmental impacts as a result of the respective actions, and as such, the NRC made a finding of no significant impact. The NRC staff finds that the conclusions set forth in these environmental assessments continue to be valid.

The HI-STORM 100 Cask System is designed to mitigate the effects of design basis accidents that could occur during storage. Design basis accidents account for human-induced events and the most severe natural phenomena reported for the site and surrounding area. Postulated accidents analyzed for an ISFSI include tornado winds and tornado generated missiles, design basis earthquake, design basis flood, accidental cask drop, lightning effects, fire, explosions, and other incidents. Considering the specific design requirements for each accident condition, the design of the HI-STORM 100 Cask System, would prevent loss of containment, shielding, and criticality control.

Amendment 1 to CoC 1014, Appendix B, Section 3.4.3.a, requires that the Coulomb friction coefficient for the HI-STORM 100/ISFSI pad interface be at least 0.53 under all conditions. Amendment 2 to CoC 1014, Appendix B, Section 3.4.3.a. includes a provision, that for free standing casks, the response of the casks under the site's Design Basis Earthquake (DBE) could be established using the best estimate of the friction coefficient in an appropriate analysis model. The analysis would demonstrate that the DBE would not result in cask tip-over or cause a cask to fall off the pad, or cause an impact between casks, or if an accident were to occur, would demonstrate that the maximum g-load experienced by the stored spent nuclear fuel would be limited to 45 g's. The use of methods described in Section 3.4.3.a of Appendix B, approved by the NRC in Amendment 2 to CoC 1014, in demonstrating the safe storage of spent nuclear fuel during environmental conditions that might degrade the pad/cask interface friction, such as those caused by icing, will not result in any degradation of specific design requirements, namely, containment, shielding or criticality control. Without the loss of either containment, shielding, or criticality control, the risk to public health and safety is not compromised.

By permitting the use of methods described in Section 3.4.3.a of Appendix B, approved by the NRC in Amendment 2 to CoC 1014, there will be a reduction in occupational exposure due to the relief from the performance of compensatory measures. Therefore, the NRC staff has determined that acceptable safety margins are maintained and that there are no significant environmental impacts as a result of using the methods described in Section 3.4.3.a of Appendix B, approved by the NRC in Amendment 2 to CoC 1014, to demonstrate safe storage of spent nuclear fuel at the CGS ISFSI.

IV. Alternatives to the Proposed Action

The staff evaluated the no action alternative, which would be a denial of the exemption request. Denial of the exemption request would result in continued performance of compensatory measures by Energy Northwest, thereby continuing to subject workers to an increased radiation dose than would be the case if the compensatory measures were not conducted.

V. Agencies and Persons Consulted

On October 27, 2006, Mr. Michael Mills of the State of Washington Energy Facility Site Evaluation Council was contacted about the EA for the proposed action and had no concerns.

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. The proposed action will not have a significant effect on the quality of the human environment because the use of the Amendment 2 methodology will reduce worker radiation dose, and further, will not result in any degradation to specific cask design requirements, namely, containment, shielding, or criticality control. As described in the foregoing EA, the Commission finds that the proposed action of granting an exemption from 10 CFR 72.212(a)(2), 72.212(b)(2)(i)(A), 72.212(b)(7), and 72.214, pursuant to 10 CFR 72.7, which will permit Energy Northwest to perform analyses consistent with that granted by the NRC in Amendment 2 to CoC 1014, Appendix B, Section 3.4.3.a at the CGS ISFSI, is not a major Federal action significantly affecting the quality of the human environment and, therefore, an environmental impact statement is not required.

Further Information

In accordance with 10 CFR 2.390 of NRC's “Rules of Practice,” final NRC records and documents regarding this proposed action, including the exemption request dated September 14, 2006, are publically available in the records component of NRC's Agencywide Documents Access and Management System (ADAMS). These documents may be inspected at NRC's Public Electronic Reading Room at http://www.nrc.gov/​reading-rm/​adams.html. These documents may also be viewed electronically on the public computers located at the NRC's Public Document Room (PDR), O1F21, One White Flint North, 11555 Rockville Pike, Rockville, MD 20852. The PDR reproduction contractor will copy documents for a fee. Persons who do not have access to ADAMS or who encounter problems in accessing the documents located in ADAMS, should contact the NRC PDR Reference staff by telephone at 1-800-397-4209 or [phone], or by e-mail to [e-mail].

Dated at Rockville, Maryland, this 20th day of November 2006.

For the Nuclear Regulatory Commission.

Christopher M. Regan,

Senior Project Manager, Division of Spent Fuel Storage and Transportation, Office of Nuclear Material Safety and Safeguards.