The 16th and final HI-STORM FW dry storage system has been placed into the dry storage building at the Krško NPP in Slovenia, US-based Holtec International said on its Facebook page. Slovenian nuclear utility Nuklearna Elektrarna Krško’s (NEK’s) used fuel dry storage facility at Krško NPP was commissioned ahead of schedule in April with the placement by Holtec of the first cask. Placement of the 16th cask marks completion of the first loading campaign Holtec noted. “We thank our partners at NEK for their support in project preparation and execution that led us to such a successful conclusion.”

Transfer to dry storage of the 16 casks containing 592 used fuel rods was supervised by the Slovenian Nuclear Safety Administration (URSJV – Uprava republike Slovenije za jedrsko varnost) and monitored by other authorised organisations. NEK says the dry storage will meet all the conditions needed for extended operation of the Krško NPP for an additional 20 years (to 2043), for which it has a final environmental consent.

Construction of the 696 MWe Westinghouse pressurised water reactor – first western NPP in eastern Europe – began in 1975 and it began commercial operation in 1983. Construction of the dry storage facility began after Holtec won the contract in 2017.

The HI-STORM FW casks are qualified to a severe earthquake level that produces foundation pad accelerations 2.1 times higher than the earth’s gravity. They are also engineered to withstand impact from a military or commercial aircraft, exceeding the International Atomic Energy Agency’s (IAEA’s) guidance for operating NPPs.

NEK says the technology provides a high level of safety for workers and the environment during the transfer of the used fuel elements from the pool to containers and the transport of the containers to the dry storage as well as for the entire period of temporary storage. The containers can also be used to transport the used fuel to a final repository in future.

Image: The last HI-STORM FW dry storage system has been placed into the dry storage building at the Krško NPP in Slovenia (courtesy of Holtec)