Method for determining nuclear reactor element worths

A method for determining nuclear reactor element worth is proposed which consists in the fact that the reactor is brought out into a supercritical state and then by the investigated element displacement it is brought out into a subcritical state during which the neutron flux before, during and after the element displacement is measured at equal intervals of time by detector. To increase the method accuracy by eliminating the errors conditioned by non-removable external neutron source and detector efficiency instability, the steady-state neutron flux before the reactor bringing out into the supercritical state and after its transfer into subcritical state is additionally measured. After that the efficient external sourse and reactivity for reactor supercritical state are additionally determined. Application of the method proposed allows one to create more optimized, more efficient research and power reactors with large external neutron sources and to improve nuclear safety conditions as it allows one to obtain a more precise and reliable evaluation of reactivity effect for various modes