On the Feynman-alpha method for reflected fissile assemblies

The Feynman-alpha method is a neutron noise technique that used to estimate the prompt period of fissile assemblies. and quantity are widespread interest including in applications such as nuclear criticality safety, safeguards nonproliferation, stockpile stewardship; may also be infer keff multiplication factor. predicated on time-correlated detections deviate from Poisson random variable due multiplication. Traditionally, measurements diagnosed with one-region point kinetics, but two-region models required when assembly reflected. This paper presents derivation kinetics equations based double integration Rossi-alpha equations, develops novel propagation measurement uncertainty, validates theory. Validation achieved organic scintillator weapons-grade plutonium reflected by various amounts copper achieve values 0.83–0.94 periods 5–75 ns. results demonstrate should use model instead model. simplified deviates validated much 10% period, reduces for small reflector. estimates compared those approach. comparative more precise than accurate keff<0.92, whereas generally higher multiplications. uncertainty developed this work all will therein improve fitting accuracy appropriate precision estimates.