Verification and Validation of Monte Carlo n-Particle Code 6 (MCNP6) with Neutron Protection Factor Measurements of an Iron Box.

摘要

Using a 1984 benchmark experiment, MCNP6 replicated the neutron flux and neutron protection factor (NPF) measurements of an iron box, which simulated a basic military vehicle, resulting in less than 5% difference from the published results. Additionally, the neutron flux spectrum of a 239 PuBe source was characterized using a Bonner Sphere Spectrometer (BSS) and the solution unfolded using the Maximum Entropy Deconvolution (MAXED) program, producing a X2/df of 0.97. Utilizing a steel box provided by the DTRA, measurements of neutron flux from a D-D neutron accelerator were recorded via BSS inside and outside of the box. Both flux spectra were unfolded through MAXED using MCNP6 computations as a priori, which resulted in X2/df values of 0.86 and 0.91, respectively. NPF assessments of the steel box were then conducted using experimental and MCNP6 flux spectra for the box, as well as H*(10) scaling, with final results differing by less than 1%. MAXED software was leveraged for all flux spectrum unfolding, incorporating updated BSS response functions generated within this research from MCNP6. This experiment and its conclusions strongly support the verification and validation of MCNP6 for modeling NPF assessments of military vehicles.