An important objective during a nuclear power plant emergency is to avoid the release of radioactive materials to the environment. At Kola Unit 2 in Russia, new, highly efficient valves have been installed to contain steam and radioactive fission products in an accident. The new valves were installed in the piping of the existing confinement system.

These new confinement isolation butterfly valves are designed to spring into action through a system of sensors and actuators. When a sensor detects an abnormal situation, it will signal an actuator to close the correct valve(s).

A total of 11 confinement isolation valves, valve actuators and sensors were manufactured by U.S.-based Enertech (and supplied in conjunction with another U.S. firm, Burns & Roe) and were installed in the ventilation system piping.

The confinement isolation valves provided at Kola offer numerous features that will ensure a long operating life and enhanced nuclear power plant safety. The valves are nuclear grade, and are manufactured to meet exacting standards for precision and service. The seating components are laminated stainless steel coupled with a graphite seat ring. This metal-to-metal seat requires little, if any, maintenance. Because the seat is retained within the body of the valve, there is reduced seat erosion.

The valves are designed to perform well under severe operating conditions. In the Kola reactors, the valves have been installed near the confinement wall penetrations through which the ventilation system passes.