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

252 Cf neutron source was CFBR-Ⅱreactor’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 252 Cf neutron source. Neutron count rate arosed by bare 252 Cf neutron source and bare Am-Be neutron source were measured respectively.Leakage neutron count rate of CFBR-Ⅱreactor 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 252 Cf source’s. These parameters were applied to CFBR-Ⅱreactor’s running.