High Order Harmonic Wave Filtering Method Used In Prompt Neutron Attenuation Constant Calculation Of ADS Sub-Critical Reactor

MUSE（Multiplication with an external source） series experiments carried out by the EU show that the Pulsed Neutron Source（PNS） method is appropriate for keffmeasurement in deep sub-critical conditions.In PNS method,the accuracy of prompt neutron attenuation constant α plays a key role for accurately keff measurement.In this paper,the analysis of α constant measurement on fast-thermal coupled subcritical facility Venus-1# is performed.By using high order harmonic wave filtering technique,the time interval for α fitting is obtained and the fitted α values are spatially independent with locations of detectors.Furthermore,the comparison of prompt multiplication factors kpderived from fitted α and calculated by MCNP（Monte Carlo N Particles） is made,which shows a good conformation.Results in this research indicate that,the high order harmonic wave filtering method can effectively avoid the problem that the measured α values depend on the locations of detectors,and the α values obtained from which can be used for keff off-line monitoring in ADS sub-critical reactors.