Transfer of irradiated FiR 1 TRIGA fuel to reuse at USGS

The FiR 1 TRIGA reactor on the Otaniemi Campus close to Helsinki, Finland, was permanently shut down in June 2015. The reactor is under the US DOE FRR spent fuel return program, but due to political and administrative reasons, the DOE INTEC facility in Idaho was not allowed to receive the used fuel from FiR 1. In 2020 a new path for repatriation of the fuel to the United States was opened culminating in US Geological Survey (USGS) TRIGA reactor (GSTR, Denver, Colorado) receiving early 2021 all the irradiated fuel from FiR 1. This solution between USGS and VTT was elaborated with the assistance of the Edlow International Company (EIC). It included USGS and DOE agreeing on the disposition of also FiR 1 irradiated fuel inventory and NRC accepting to expand the USGS’s license limits to include the full FiR 1 irradiated fuel inventory. USGS is planning for an intensive use of the reactor during the current operating license valid till October 2036 and is therefore in need of more fuel. USGS has identified that the FiR 1 fuel is suitable to be used in the GSTR and has significant burnup capacity left. VTT contracted EIC to transfer the irradiated fuel from FiR 1 to GSTR. EIC contracted NAC International to carry out the transfer using the NAC-LWT cask and associated fuel-handling systems [1]. Fortum Power and Heat was contracted to establish the local transport and support organization in Finland. Cask loading and road transport in Finland took place under VTT license granted by the Finnish Radiation and Nuclear Safety Authority - STUK. The cask loading took place late December 2020, and on 29th December, the Pacific Nuclear Transport Limited (PNTL) nuclear fuel carrier Pacific Grebe sailed off from the Port of Helsinki. Failed fuel was put into five sealed failed fuel cans. A team from Idaho National Laboratory witnessed this as these cans will be transferred in the future intact to INTEC Idaho. This article describes the arrangements for cask loading in the middle of the Finnish winter along with the actual transfer of the fuel from the reactor tank and the dry pits to the NAC-LWT cask outside the reactor building inside a weather cover tent. The intense two-week operation involved some thirty people in a Finnish-US team.