Rosatom preps to unload fuel rods from Lepse service vessel

lepse header. (Photo: Thomas Nilsen) The Lepse. (Photo: Thomas Nilsen)

Officials in Russia have set a beginning date for removing hundreds of spent nuclear fuel assemblies from the bowels of the Lepse nuclear service ship, one of the country’s most radioactively contaminated Cold War legacy vessels.

Anatoly Zakharchev, who is overseeing the fuel removal process for state nuclear corporation Rosatom, said in a recent interview that the complicated process of extracting the spent fuel from the ship would begin in the last quarter of 2018.

The fuel removal process ­– including the extraction of several damaged assemblies ­– is one of the most technically demanding nuclear legacy cleanup operations Russia has ever undertaken. When it’s complete in 2020, it will be a decades-long culmination of technical preparation and represent the coordination of millions of dollars in international funding during often trying political circumstances.

The new phase in the Lepse dismantlement is also another remarkable development toward cleaning up naval and civilian nuclear debris in Northwest Russia. In June, the first containers of spent nuclear fuel that accrued over fifty years at Andreyeva Bay were hauled away for storage. Both are projects that Bellona has long advocated for.

backside-Lepse The Lepse's stern section, cut away. (Photo: Nerpa Shipyard)

During its 30-year career, the Lepse was used to unload spent nuclear fuel from Soviet nuclear icebreakers. After its decommissioning, the ship spent more than two decades laden with its radioactive cargo at the Atomflot icebreaker port in Murmansk, just four kilometers from the city’s population of 300,000.

Its irradiated holds contain 639 spent nuclear fuel assemblies, many of which were damaged when the vessel refueled the Lenin Icebreaker in 1965 and 1967, and which defy removal by conventional means.

The boat was finally towed from Atomflot to the Nerpa naval shipyard in September 2012, after more than a decade of strenuous negotiations among Bellona, the Russian government and financial institutions – most notably the European Bank of Reconstruction and Development – to mobilize funding for its disposal.

Bio-protection-Lepse Steel bio-protection shields surrounding the Lepse's bow. (Photo: Nerpa Shipyard)

Once it got to Nerpa, the 79-year-old Lepse ran into a traffic jam and bobbed neglected on the water until 2014, when, during foul weather conditions and thick fog, it was finally docked.

Rosatom’s Zakharchov said in his interview that remote controlled spent fuel removal cranes developed especially for the Lepse project had been successfully tested.

Once the Lepse was put into dry-dock at Nerpa, it was cut into five sections, or “storage packages”: the stern section, which is said to be relatively uncontaminated; the section with liquid radioactive waste tanks; the engine and boiler room, and two packaged bow sections, one of which contains the notorious 639 spent nuclear fuel assemblies.

When it was hauled out of the water onto a special slipway, the bow storage package, along with the side sections, was completely enclosed to ensure climate control for the spent nuclear fuel assemblies inside.

The vessel was also fitted with a communications system, a ventilation system and trace gas detection equipment to ensure safety for the 5000 technicians working on its dismantlement.

Lepse-1. The Lepse. (Photo: Nerpa Shipyard)

Radiation safety shields have also been erected around the perimeter of the vessel, and additional protections were added around the bow to prevent some 4600 microsieverts of radiation from escaping into the surrounding environment.

After the vessel was pulled out of the water onto its slipway, decommissioning engineers began forming the storage packages – essentially big blocks holding the remains of the vessel. These will be shipped to long-term storage in Sayda Bay, a refurbished storage site on the coast of Kola Bay where dozens of reactor compartments from other nuclear vessels are housed.

The Lespe was built in 1934, and served and as a floating fuel unloading point for Soviet Icebreakers from 1961 until its retirement in 1988. That year, it was docked at Atomflot.

In 1994, the vessel and the dangers it posed to Murmansk caught Bellona’s eye, and the organization mobilized the European Union to allocate funding toward removing it from the city’s harbor and safely dismantling it.

But when it was towed to Nerpa, the Lepse ran into further complications. Rosatom and the Ministry of Defense were locked in a quarrel about what to do with the Leninsky Komsomol nuclear submarine – the Soviet Union’s first ­– which was taking up the Lepse’s berth.

Those difficulties were finally resolved two years ago, and the Lepse was gingerly moved from the water to dry dock. The Leninsky Komsomol, which had already been cut into three pieces, was welded back together as a museum piece.

 

Charles Digges

charles@bellona.no