Neutronics and Dose Reduction Strategies for STS Using Advanced Monte Carlo Techniques

The Second Target Station (STS) at the Spallation Neutron Source at Oak Ridge National Laboratory is a major initiative to develop a next-generation spallation neutron source. It will utilize a rotating, water-cooled tungsten target driven by a 700-kW, 1.3-GeV pulsed proton beam to tackle emerging challenges in materials science, nuclear physics, and technology. The STS will provide advanced cold neutron beams and house 18 state-of-the-art instruments designed to deliver enhanced high-resolution measurements and increased neutron beam intensity. The system will be equipped with two cryogenic liquid hydrogen moderators, complemented by water pre-moderators and a beryllium reflector.

In this presentation, I will discuss neutronics optimization studies using advanced radiation transport Monte Carlo methods with sophisticated variance reduction techniques, focusing on the design of key STS components. These include the innovative bunker, designed to house and shield the neutron production target, and the downstream utilities area intended for handling spent target components and materials from its operations. Emphasis will be placed on prompt dose evaluations in personnel access areas.