Extended interim storage

The indefinite deferral of or lack of decision about the next activity of RRSF management, spent fuel processing, might lead to the extended interim storage option. 

The decision to water store spent fuel for periods longer than originally expected should be carefully compared with the option of migrating to dry storage. The final decision should be taken comparing the cost of both options. 

There is general agreement among the authors of this report that the current technical, economic and institutional status suggests that the countries of the region will likely implement the extended interim storage option for all research reactors. 

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The aim of extended interim storage is to maintain the integrity and retrievability of the spent fuel for a definite or even indefinite time period. It is considered that extended interim storage lasts beyond 20 years. 

It is likely that processed spent fuel, i.e. either LILW or HLW, will be stored in extended interim dry storage in each country of the region until a deep geological repository is available. 

At SRS and other basins storing US defence related spent nuclear fuel, extensive efforts are under way to improve fuel storage conditions. These efforts should result in extended storage capability. This interim wet storage, however, cannot be extended indefinitely, and provisions must be made for other disposition. The ultimate solution for this problem is processing the fuel to a more stable form using standard techniques readily available and utilized... 

In order to achieve these objectives, standard coupons assembled in racks were exposed for extended periods in the spent fuel storage basins of the nine participating countries. These specimen racks were withdrawn for interim and final inspections. This chapter provides details about (a) the materials, coupons and racks and (b) the protocol. 

Currently, aluminium based spent fuels from research reactors are in operational and interim wet storage. However, for an eventual extended storage as well as for disposal, there are some concerns about the suitability of the aluminium as a matrix resistant to water corrosion. Therefore, the preferred alternatives are extended storage in dry conditions and disposal of the derivatives from spent fuel processing instead of its direct disposal. 

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