Explosively operated valves in shafts and tubings for underground nuclear power reactors

In case of severe accidents in underground nuclear power reactors it is desirable to have redundant means to seal off the access paths. For this purpose it is proposed to utilize fast valve technology which has been developed for underground nucelar explosion experiments. Examples of such valves are described which operate in a single mode with very short closing times. These valves employ explosives, propellants and springs to drive the shutter. Problems of incorporating such valves into an underground nuclear power reactor are discussed. (orig.)