A longstanding challenge to retrieve abandoned, highly radioactive spent nuclear fuel assemblies has been completed as part of a decade-long international collaboration to address nuclear and radiological risks at Andreeva Bay in Russia, the European Bank for Reconstruction and Development said.

The nuclear fuel assemblies, which had been lying for decades at the bottom of Building 5, an old spent fuel store, have been removed and secured in a complex operation that was the first of its kind. Following the successful operation, radiation levels at the facility have fallen by over 40%, the EBRD said.

This drop in radiation levels will allow further decommissioning tasks to be performed and remove one of the most significant radiological risks to the Barent Sea region.

The spent fuel will be transported to Atomflot, near Murmansk in the northwest of Russia, for onward transportation, safe storage and reprocessing at the Mayak nuclear facility in the Urals.

The work is part of a programme to overcome the legacy of the former Soviet northern fleet. The EBRD manages an an international fund for the work financed by contributions from Belgium, Canada, Denmark, the European Union, Finland, France, Germany, The Netherlands, Norway and the UK.

The Andreeva Bay coastal base was built in the 1960s to service nuclear submarines. Following an accident in Building 5 in 1982, water leakage from one of the pools for spent fuel caused widespread contamination. In 1988-89, most of fuel from Building 5 was transferred to the three dry storage unit tanks at the site and the building was abandoned.

However, a significant volume of radionuclides remained in the sludge at the bottom of the pools and six spent fuel assemblies remained at the bottom of one of the pools in Building 5. Following a radiological survey of the storage facility, urgent repairs of the building’s roof were performed and shielding was installed.