SKB found to be fit for safe operation of waste facilities

Licensees of a nuclear facility in Sweden must by law make an overall assessment of the facility's radiation safety at least every 10 years. In September 2018, SKB submitted its overall assessments for Clab and SFR. SSM has reviewed the assessments to determine whether the requirements of the Nuclear Activities Act are met and whether SKB has the ability to maintain and increase radiation safety in the facilities until the next overall assessment.

Following its review, the regulator said today SKB's report is "well-structured and reports self-critically, systematically and clearly for the business". It deems SKB to have "the prerequisite to operate Clab and SFR in a radiation-safe manner until the next overall assessment in 2028". SSM concluded SKB "conducts appropriate activities with the aim of maintaining and increasing radiation safety"

"SKB has also identified and documented appropriate and reasonable measures and improvements in order to maintain and increase radiation safety," said Leif Jonasson, investigator at SSM and project manager for the authority's review. "The action plan has been integrated into the day-to-day operations."

However, SSM said it identified shortcomings, most of which concern the report and are typically that it is not detailed enough or that conclusions are not sufficiently substantiated. The regulator said the shortcomings have little significance for radiation safety, but that they should be remedied before the next overall assessment.

"In the overall assessment, SKB has made a thorough review of its current operations at Clab and SFR and how it intends to handle the challenges it sees during the coming ten-year period," Jonasson said. "The Swedish Radiation Safety Authority thus assesses that SKB achieves the purpose of an overall assessment."

The SFR repository, in the municipality of Östhammars, is situated 60 metres below the bottom of the Baltic Sea. It comprises four 160-metre-long rock vaults and a chamber in the bedrock, with a 50-metre-high concrete silo for the most radioactive waste. Two parallel one-kilometre-long access tunnels link the facility to the surface.

Most of the short-lived waste deposited in the SFR - which began operations in 1988 - comes from Swedish nuclear power plants, but radioactive waste from hospitals, veterinary medicine, research and industry is also deposited within it. The facility currently houses about 63,000 cubic metres of waste and is 60% full. SKB applied in December 2014 to treble the size of the SFR facility, adding a further 170,000 cubic metres of capacity. The extended part of the repository will consist of six new rock chambers, each 240-275 metres in length.

The Clab interim repository for used fuel has been operating since 1985 at Oskarshamn, and its original 5000 tonne capacity was expanded to 8000 tonnes soon after 2000, and in 2015 SKB applied to extend it to 11,000 tonnes to cater for all the fuel from all the present reactors. The used fuel is stored under water in an underground rock cavern for some 40-50 years. It will then be encapsulated in copper canisters with a cast iron internal structure for final emplacement packed with bentonite clay in a 500 metre deep repository in granite.