Valve Qualification for Normal and Accident Conditions in Light Water Reactors

The experimental qualification of safety and relief valves for boiling water reactors and pressurized water reactors is presented. Both are pilot-operated valves and were originally designed for steam flow but have to function also for water and two-phase flow under accident conditions.Tests show excellent operability of the valves with steam flow. With water, the required function was achieved after modifying the cross section and the pressure drop from and to the control volume in the main valves.