Segementation of reactor vessel internals at Oskarshman 2 (Credit: GEH)US-based GE Hitachi Nuclear Energy (GEH) has completed the segmentation of reactor internals at unit 2 of the Oskarshamn nuclear plant in Sweden.

GEH said it had dismantled, segmented and packed reactor internals of  Oskarshamn 2, a 638MWe boiling water reactor (BWR). All the handling and segmentation of reactor internals was carried out underwater.

The work was mainly carried out using the Primary Segmentation System, designed by REI Nuclear. GEH acquired the business and certain assets of REI Nuclear in December 2018.  

“This is a historical milestone for the decommissioning of OKG units 1 and 2,” commented Johan Dasht, CEO and managing director of OKG AB. “Removal and disposal of reactor internals take place directly after defuelling of the units in order to simplify further decommissioning and improve the environment in the plant.”

GEH will now continue with the dismantling and segmentation of reactor internals at the 473MWe Oskarshamn 1 BWR. 

German utility E.ON, which has a 54.5% stake in Oskarshamn, decided in October 2015 to permanently close Oskarshamn 1&2. Oskarshamn 2 closed in 2015 and Oskarshamn 1 in 2017. Oskarshamn 3, a 1400MWe BWR which started up in 1985, continues to operate.

In January 2016. E.ON spun off of its non-renewable assets into Uniper, which, in December 2018, announced a "long-term and common strategy" for the demolition of two units each at Sweden’s Barsebäck and Oskarshamn plants. All radioactive waste is due to be removed from the four units unit between 2020 and 2028. The total cost of the decommissioning is estimated at SEK10 billion ($1.1 billion).

Photo: Segementation of reactor vessel internals at Oskarshman 2 (Credit: GEH)