Ignalina Nuclear Power Plant - Reactors

Reactors

The Ignalina nuclear power plant contained two RBMK-1500 water-cooled graphite-moderated channel-type power reactors. The Soviet-designed RBMK-1500 reactor was originally the most powerful reactor in the world with an electrical power capacity of 1,500 megawatts (MW) and thermal power capacity of 4,800 MW, but this distinction was later superseded by other nuclear reactors elsewhere. After the Chernobyl disaster of April 1986 the reactor was de-rated to 1,360 MW. These are of a similar type of reactor (RBMK-1000) as at the Chernobyl power plant, hence the European Union's insistence on closing them. Each unit of the power plant was equipped with two K-750-65/3000 turbines with 800 MW generators.

In December 1983, when Ignalina Unit 1 came online, a design flaw of the RBMK was noticed for the first time. The graphite moderated tips on the control rods, which partially caused the Chernobyl accident, were entered in to the reactor. They immediately caused a power surge. In this case the control rods did not get stuck, and could get down to the bottom of the reactor. The boron in the control rods stopped the nuclear reaction. Other nuclear organizations and RBMK plants were informed of the problem, but it was not addressed until after the accident at Chernobyl. The subsequent modifications were tested at Ignalina during 1987 and 1988.