This paper describes efforts to establish a neutron imaging radiography capability in an available beam port at the University of Utah 90-kW TRIGA Reactor (UUTR) from computational analysis of the proposed beamline. We employ methods in 3-D Monte Carlo and S_N deterministic radiation transport methods to characterize the neutron beamline before its construction. Incident beam currents established using results from 3-D S_N and Monte Carlo full core models were employed as a starting point for the source term in a full-scale MCNP6 computational model of the neutron beam port system to predict the spatial and energy-dependent neutron flux expected to exit the beam pipe onto the imaging operations floor. Our analysis reveals a full-power total neutron flux of 2.5 × 10⁷ ± 1.4 × 10⁵n/cm²/s, where 92% of this flux streams through the surface normal within angle tally bin of $0^{°}<\theta <2^{°}$. This neutron flux is above the threshold of industrially relevant neutron flux magnitudes necessary to probe non-destructive imaging in high-Z materials and opens up possibilities for tomographic imaging. Further analysis regarding the functionality and optimal design of the beam port utilizes both Monte Carlo and deterministic 3-D radiation transport methods to characterize principal neutron beam line attributes such as the L/D ratio, theoretical cadmium ratios, neutron-to-photon ratio, effective beam diameter estimates, and predicted neutron flux to irradiated foil samples. These supplemental models are developed in efforts to solidify consistency between Monte Carlo and deterministic methods, as subsequent development of a radiation beamstop will employ a hybrid fashion of the two for variance reduction purposes. In addition, primary and secondary radiation dose rates are evaluated to assess parameters for safe installation, guide future irradiation tests, and design of a beam stop for optimal shielding.

本文描述了通过对拟议光束线的计算分析，在犹他大学 90 千瓦 TRIGA 反应堆 (UUTR) 的可用光束端口中建立中子成像射线照相能力的努力。我们采用 3-D Monte Carlo 和 S _N确定性辐射传输方法中的方法来表征中子束线在其构建之前。使用 3-DS _N和 Monte Carlo 全核模型的结果建立的入射束电流被用作中子束端口系统的全尺寸 MCNP6 计算模型中源项的起点，以预测空间和能量相关的中子预计会离开光束管到达成像操作层的通量。我们的分析表明全功率总中子通量为 2.5 × 10 ⁷ ± 1.4 × 10 ⁵ n/cm ² /s，其中该通量的 92% 流经角计数仓内的表面法线$0^{°}<\theta <2^{°}$. 该中子通量高于探测高 Z 材料无损成像所需的工业相关中子通量大小的阈值，并为断层成像开辟了可能性。关于束端口的功能和优化设计的进一步分析利用蒙特卡罗和确定性 3-D 辐射传输方法来表征主要中子束线属性，例如 L/D 比、理论镉比、中子光子比、有效光束直径估计，并预测辐射箔样品的中子通量。这些补充模型的开发是为了巩固蒙特卡罗和确定性方法之间的一致性，因为辐射光束停止器的后续开发将采用两者的混合方式来减少方差。此外，