Russia plans start-up of first Gen-III unit this summer

The first fuel assembly was loaded at unit 2 of the Novovoronezh II nuclear power plant in western Russia on 24 March at 3.28am, while the "active phase" of the loading process began the following day.

Novovoronezh 6 is a Generation-III VVER 1200/392M pressurised water reactor (PWR) unit with a design net capacity of 1114 MWe. It is the first of two units at Novovoronezh II - the lead project for the deployment of the AES-2006 design incorporating a Gidropress-designed PWR, an evolutionary development from the VVER-1000. Construction of Novovoronezh II units 1 and 2, also known as Novovoronezh units 6 and 7, began in June 2008 and July 2009, respectively. The original Novovoronezh site nearby already hosts three operating reactors and two that are being decommissioned.

Russian regulator Rostechnadzor issued the operating licence for Novovoronezh 6 on 23 March, thus permitting first criticality and eventual commercial operation of the unit.

The announcement of the start of fuel loading at unit 2 followed a meeting chaired by Novovoronezh plant director, Vladimir Povarov, and the general director of ASE Group, Valery Limarenko. The meeting included an inspection of the unit's reactor building and control room as well as its solid radioactive waste reprocessing and nitrogen-oxygen facilities.

The meeting was also held to discuss "equipment supply, the timing of obtaining permits, the progress of individual operations necessary for achieving the minimum controlled power level, as well as the progress of preparations for the first criticality of unit 6," ASE Group said.

Povarov said the fuel loading procedure was different to those previously used at pilot power units because the reactor core of Novovoronezh 6 will be partly filled with fuel assembly "dummies". This will "ensure additional safety" during the first criticality phase, Povarov said. In the same statement, Fedor Tatarkin, chief engineer at the Novovoronezh plant, said that at the first stage of fuel loading, just one-third of all loaded assemblies will contain fresh nuclear fuel, while the rest will be dummies. The dummy assemblies will be gradually replaced by fresh nuclear fuel in accordance with the operating schedule, he added.

Achieving start-up of the unit according to schedule requires "strict adherence" to all stages of preparation for its launch, Povarov said. "If there are any risks [to the schedule], then we need to know about them in advance in order to resolve them quickly," he said.

Limarenko added that, "despite the very tight schedule, every effort will be made to ensure the unit is connected to the network in a timely manner".

As of today, 108 of a total of 163 of the fuel assemblies have been inserted and fuel loading is to be completed on 2 April, according to the ASE Group statement. Physical start-up will take about 55 days, with commercial operation to start by the end of this year, Povarov said.

ASE Group consolidates the engineering know-how of Russian state nuclear corporation Rosatom through the ongoing merger of NIAEP, ASE and Atomenergoproekt.

Several generations of reactors are commonly distinguished. Generation I reactors were developed in 1950-60s, and outside the UK none is still running today. Generation II reactors are typified by the present US and French fleets and most in operation elsewhere. So-called Generation III (and III+) are advanced reactors, though the distinction from Generation II is arbitrary. The first are in operation in Japan and others are under construction or ready to be ordered. Generation IV designs are still on the drawing board and will not be operational before 2020 at the earliest.

The new Novovoronezh units will have a passive heat removal system that, in the event of loss of on-site power supply, will provide long-term heat removal from the reactor core to the atmosphere using natural circulation.