Absolute measurement of reactivity of sub-critical reactor system comprises counting neutrons before and after switching on external neutron source

摘要

The process for obtaining an absolute measurement of the reactivity of a sub-critical system comprising a reactor fed by an external neutron source comprises putting the reactor (1) into a first sub-critical state, switching on the external neutron source (2) and counting the neutron flow representative of the first sub-critical state. The external neutron source is then switched off, the reactor is put into a second subcritical state, and the source is switched on again to provide a second neutron flow measurement. The measurements are then applied to a given formula to obtain an absolute value.