Spent nuclear fuel

SNF storage

There are several options for long-term storage of SNF. The three major options for LWR SNF are pool storage at the reactor or a centralized site, dry cask storage at the reactor or a centralized site, and storage/disposal in a repository. All can provide long-term, safe SNF storage. Centralized storage has become the preferred option for many countries (e. g., France, Japan, and Sweden) with significant nuclear power programs.

The current fuel cycle in the United States is an open (or once-through) fuel cycle. Nuclear fuel makes a single pass through a reactor, after which the SNF is removed, stored for a period, and then directly disposed of in a geological repository for permanent isolation. Other fuel cycles (partial recycle or closed fuel cycle) are currently under evaluation but no deploy­ment date has been established. The disposal of SNF and HLW has been a technical and institutional challenge for the United States. However, the United States has successfully sited and operated WIPP — a geological repository for the disposal of defense transuranic (plutonium) wastes — for over a decade.

Dry cask storage is currently the preferred option for long-term storage of SNF because the cask has no moving parts (natural circulation air-cooling for decay heat removal) and requires very little maintenance. As with transport casks, there are economic incentives to storing the fuel in the pool for a decade before transfer to dry cask storage.

The possibility of storage for a century, which is longer than the antici­pated operating lifetimes of nuclear reactors, suggests that the United States should move toward centralized SNF storage sites, starting with SNF from decommissioned reactor sites and in support of a long-term SNF management strategy. Ideally, such storage sites would be at repository sites or at sites capable of future expansion to include reprocessing and other back-end facilities should the United States choose a closed fuel cycle. While this proposal is made in the context of a better long-term fuel cycle system, it also addresses two near-term issues: SNF at decommissioned sites and federal liability for SNF storage.

The federal liability for SNF storage is a result of changing federal poli­cies and delays in the repository program. At the time when most US NPPs were built, it was assumed that LWR SNF would be reprocessed. The plants were built with limited SNF storage capacity because of the expectation that SNF would be shipped within a decade to reprocessing plants for recovery and recycle of plutonium.

US government decisions in the 1970s not to allow commercial reprocess­ing and the resultant national decision to dispose of SNF directly ultimately led to a decision to ship SNF from reactors directly to a geological reposi­tory. Under the NWPA, utilities signed contracts with the federal govern­ment for disposal of SNF with removal of SNF from reactor sites starting in 1998. As reactor SNF storage pools filled and it became evident that the US government would not meet its contractual obligations to receive SNF, utilities began to construct modular dry-cask storage systems for their SNF to enable continued operation of the reactors.

There is a growing national obligation to utilities to address the inability of the government to remove SNF from nuclear plant sites, according to contracts signed with the DOE. The costs are meant to cover the expenses utilities have incurred to build their own dry cask storage facilities at their sites. By 2020, most of the utilities will have built their own ISFSIs for which the government will have to pay as required by court decisions.

The Private Fuel Storage Company (PFS), a utility consortium designed and licensed as an ISFSI in Utah, is a limited liability company (LLC) formed from eight commercial nuclear utilities that attempted to establish an interim waste storage facility on the Skull Valley Goshute Reservation in Utah. The project proposed to store 40,000 metric tons of irradiated fuel in dry cask containers above ground on concrete pads.

The NRC issued a license to PFS on February 21, 2006, but conditioned construction authorization on the company first arranging for adequate funding. On February 21, 2007, progress in developing the facility was indefinitely delayed by actions of the US Department of the Interior, which disapproved the lease arrangement between PFS and the Skull Valley Band and denied PFS the use of public lands for an intermodal transfer facility. The 10th Circuit Court of Appeals vacated decisions by the US Department of the Interior that blocked construction of PFS in June 2010. The ruling returned the PFS application for a right-of-way and lease of tribal land to the Department of the Interior for further consideration. The Department of the Interior was still considering the request in December 2012, when PFS submitted a letter to the NRC requesting that the license be terminated to avoid future licensing fees.

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