Calculation of CFBR-Ⅱ’s Prompt Neutron Decay Constant at Delayed Criticality by the Simulated Burst-Neutron Method

By calculating foreign benchmark assemblies prompt neutron decay constants at delayed criticality, it is proved that the results calculated is faithful by using the simulated burst-neutron method. CFBR-Ⅱ’s prompt neutron decay constants are calculated with the method at five subcritical states. The prompt neutron decay constant attained at delayed criticality is 0.55μs^-1 by linear extrapolation.There are difference between calculational result and the experimental result. The article simply analyses reasons for the difference.