AEM Technology sees milestone with first VVER-TOI

AEM Technology has completed the manufacture of the bottom of the reactor vessel for unit 1 of the Kursk II nuclear power plant under construction in western Russia. This is the first of the VVER-TOI (typical optimised, with enhanced information) design nuclear reactors.

AEM Technology has completed the manufacture of the bottom of the reactor vessel for unit 1 of the Kursk II nuclear power plant under construction in western Russia. This is the first of the VVER-TOI (typical optimised, with enhanced information) design nuclear reactors.

The bottom of the VVER-TOI vessel for Kursk II-1 (Image: Rosatom)

Atomenergoproekt, which like AEM Technology is a subsidiary of Russian state nuclear corporation Rosatom, announced the VVER-TOI design in 2010. This design has an upgraded pressure vessel, increased power to 3300 MWt and 1255-1300 MWe gross (nominally 1300), improved core design to increase cooling reliability, further development of passive safety with 72-hour grace period requiring no operator intervention after shutdown, lower construction and operating costs, and 40-month construction time. It will use a low-speed turbine-generator.

Announcing completion of the reactor vessel bottom today, AEM Technology said the procedure had been carried out in two stages. The Volgodonsk branch of its subsidiary Atommash conducted thermopressing and 'punching' during heating of the component for six hours at a maximum temperature of 1070 degrees and placing a 300 millimetre-thick sheet weighing 64 tonnes onto it with a force of 12,000 tonnes.

Rosatom describes the VVER-TOI as the "logical development" of its so-called Generation 3+ units and an "evolutionary step" in improving the reactor vessel design of high-capacity plants. This design provides for an increase in the dimensions of the shell of the core of the reactor vessel, the use of improved welding materials, and the optimisation of the design of steam generators, the corporation says. The design also "ensures high economic performance with the maximum safety level of the unit", it adds.

Kursk II will replace four RBMK units currently operating at the site and commissioning of the first two Kursk II units will be synchronised with the closure of Kursk 1 and 2.

In 2015, Rosatom's nuclear power plant operator subsidiary, Rosenergoatom, announced its plan to decommissioning nine units by 2023 - four VVERs (Kola 1&2, Novovoronezh 3&4), three RBMKs (Leningrad 1&2 and Kursk 1) and the four small Bilibino EGPs, total 4808 MWe gross, 4573 MWe net. Three more RBMK units (Kursk 2, Leningrad 3&4) and the Beloyarsk 4 BN-600 fast reactor are due to retire by 2027, total 3600 MWe gross, 3427 MWe net. 

Researched and written
by World Nuclear News