Measurement of CFBR-Ⅱ Reactor’s Initialization Multiplication Started up by Am-Be Neutron Source

²⁵²Cf neutron source was CFBR-Ⅱ reactor’s old start-up neutron source. Its neutron emissivity became too weak to be used because of short half life. Am-Be neutron source, which has long half time, was choosed to replace ²⁵²Cf neutron source. Neutron count rate arosed by bare ²⁵²Cf neutron source and bare Am-Be neutron source were measured respectively. Leakage neutron count rate of CFBR-Ⅱ reactor started up by these two kinds of sources were also measured respectively. According to these data, initialization multiplications of Am-Be source were gained in proportion to ²⁵²Cf source’s. These parameters were applied to CFBR-Ⅱ reactor’s running.