Preliminary Study on Determination of ²³⁵U and ²³⁹Pu Using Delayed Neutron Counting Method

The preliminary study on the measurements of ²³⁵U and ²³⁹Pu in ²³⁵U-²³⁹Pu mixture using delayed neutron counting method was introduced. All samples were irradiated for 30 s at China Institute of Atomic Energy, cooled for 2 s, and counted for 100 s using a delayed neutron detector. It is found that the detection limits of ²³⁵U and ²³⁹Pu are 0.14 and 0.18 μg for ²³⁵U and ²³⁹Pu, respectively. The detection efficiency for delayed neutron is 0.015 0±0.001 0. The relative deviations between calculated mass and measured mass of ²³⁵U and ²³⁹Pu are 0.8% and 6.9%, respectively, for m(²³⁵U)/m(²³⁹Pu) of ²³⁵U-²³⁹Pu mixture sample is 1.2.