Measurement of the Effective Capture Cross Section of ²³⁸Np in the High Flux Isotope Reactor

The cross sections of ²³⁷Np and ²³⁸Np are important for accurate modeling and simulation of ²³⁸Pu in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). Uncertainties in these cross sections can impact the ability to predict and optimize the target design and loading for ²³⁸Pu production targets. The effective capture cross section of ²³⁷Np in the location of pneumatic tube 1 in HFIR was measured as a first step in the measurement of the ²³⁸Np capture and fission cross sections. This paper describes the flux measurements, ²³⁷Np experiments, and data analysis of the ²³⁷Np capture cross section in HFIR.