PROCEDE ET APPAREIL POUR MESURER L'ETAT DE COMBUSTION D'UN COMBUSTIBLE NUCLEAIRE

摘要

Process for measuring the state of combustion of a nuclear fuel comprises measuring the fast neutron count of the fuel. The state of combustion is then red from a curve giving the relation calculated from the ratio of emission of neutrons and the state of combustion of a nuclear fuel having a comparable history, the rate of emission corresp. to the neutron count obtd. by multiplying the count by the ratio of rate of emission of neutrons given by the curve of comparable fuel history and the known state of combustion of a similar for its count treasured in similar manner. When fuel is removed from a nuclear reactor by virtue of being "spent" or as a result of fissure etc. it has to be stored. If the state of combustion can be read from known data and the current rate of neutron emission, the remaining life, its remaining content of U (235) etc. can be calculated so that it can be stored in an appropriate location according to its activity. The distance between the used fuel units can be reduced provided their activity state is known, without initiating a chain reaction while still maintaining an adequate safety margin. The moderator used is pref. water or polyethylene.