Small Reactor Design

The D-5 small reactor design team is nationally recognized as a leader in the high-fidelity, coupled nuclear/mechanical/structural/thermal hydraulic design and analysis of space reactor systems, including deep space and surface power systems and nuclear thermal propulsion systems.

The design process integrates a thermal/structural fuel element analysis, along with a system hydraulic and nuclear solution, to provide realistic design simulations for comprehensive solutions. The fuel element analysis sizes a fuel pin based on specified design requirements, such as temperature, conduction gap size (beginning and end of life), operational lifetime, and pellet/clad materials. Material property data are used to assess both thermal- and irradiation-induced swelling of fuel meat and clad. That information is combined with predicted peak pellet fission gas releases to evaluate the generated fuel pin stresses and, ultimately, clad strain.

In addition to reactor design and assessment capabilities, the team has a highly developed spatial reactor shielding methodology for the design of shadow and component radiation shielding solutions as functions of required dose limitations. The analytical capability of computational fluid dynamics allows the team to evaluate complex fluid systems, such as water radiation shields requiring convection flow for cooling. A fundamental part of our work entails the design, development, and implementation of engineering demonstration units or test articles. Mockups of electrically heated space reactors allow the team to assess hot steady-state and transient reactor system scenarios.

The methodologies used by the team are extremely flexible and portable, allowing them to be applied to terrestrial reactor systems, as well as space reactor systems. Complementing the nuclear/thermal/structural work is an automated finite difference (FD) modeling tool for determining structural reactor stresses and strains accurately as a function of FD-evaluated spatial temperature distributions.

Biographies

• Dr. David Poston
• Thomas Marcille
• Richard Kapernick

Publications

• Poston, David
• User's Manual, Version 2.0 for Monteburns, Version 5B (pdf)
• Design and Analysis of the SAFE-400 Space Fission Reactor (pdf)
• Design of A Heatpipe—Cooled Mars Surface Fission Reactor (pdf)
• Nuclear Safety Calculations for Heatpipe Power System (HPS) Reactors (pdf)
• Los Alamos National Laboratory's Capability for Enabling Both "Early Flight" and "High Performance" Space Fission Reactors (pdf)