Builders have begun installing the dome of the reactor building of Russia’s multi-purpose fast neutron research reactor MBIR at the industrial site of the Research Institute of Atomic Reactors (NIIAR – part to Rosatom) in Dimitrovgrad (Ulyanovsk region).

The 150MWt multi-purpose sodium-cooled fast neutron reactor will be the world’s largest facility of its kind. It is expected to provide the nuclear industry with a modern and technologically advanced research infrastructure for the coming 50 years. Its unique technical characteristics will make it possible to solve a wide range of research problems to support the development new competitive and safe NPPs, including fast reactors based on closing the nuclear fuel cycle. Research time needed at the new reactor will be several times less in comparison with the currently operating installations.

Rosatom says the construction of MBIR is the most important project for the long-term development of the experimental base of Russia’s domestic nuclear industry, “which will ensure Russia's leadership in the development of innovative reactor technologies for the next half century”.

MBIR will be the basis of an international research centre (ICC MBIR). It will replace the BOR-60 experimental fast reactor that has been in operation at NIIAR since 1969. BOR-60 is due to close in 2025. MBIR will be used for materials testing for Generation IV fast neutron reactors. It will be capable of testing lead, lead-bismuth and gas coolants and will enable reactor and post-reactor experiments, perfecting technologies for the production of isotopes and modified materials.

The chief designer of the project is the NA Dollezhal Scientific Research & Design Institute of Power Engineering (JSC Nikiet); the scientific supervisor is the AI Leipunsky Institute of Physics & Power Engineering (IPPE); the general designer is GSPI: and the general construction contractor is JSC Orgenergostroy Institute.

The process of erecting the dome includes the installation of 22 arches about 12 metres high, each weighing 74 tonnes. The span of the arch is 38 metres. The dome elements were manufactured at the Nizhny Tagil Metal Structures Plant, a leading manufacturer of industrial, civil and special-purpose construction products.

“The work includes 22 stages, each of which is a complex technological operation and requires extensive preparation,” said Sergey Kiverov, NIIAR Deputy Director responsible for facilities under construction. “This includes, pre-assembly of structural elements on the ground, followed by slinging and lifting to the design level. Crane operators, slingers, welders and engineers are involved in the installation, in total more than 100 builders were involved.”

Kiverov noted that the pre-assembly of the first arch took about 14 days, and its direct installation took four hours. The work was carried out using a heavy crawler crane with a lifting capacity of 750 tonnes.

Gennady Sakharov, Director for Capital Investments, State Construction Supervision & State Expertise at Rosatom said this process indicates the closing of the thermal circuit of the reactor building. “All arches will be installed by the end of this year. Work on the construction of MBIR is being carried out on schedule, using the planned number of personnel,” he explained.

Image: Installation of the dome of the reactor building at the MBIR construction site (courtesy of Rosatom)