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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
Jarod Wilson, Sara Hauptman, Akshay Dave, Kaichao Sun, Lin-wen Hu (MIT), Ruimin Ji, Yang Zou (CAS)
Proceedings | 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) | Charlotte, NC, April 8-11, 2018 | Pages 76-83
The growing global demand for emission-free energy is creating a market for advanced Generation-IV NPP, and the Fluoride salt-cooled High-temperature Reactor design with a pebble-type fuel is a promising candidate. However, this design also brings unique challenges, namely evaluating the effects of the fuel’s distribution and dynamic movement. Generating explicitly described fuel pebble loading patterns is non-trivial. This study serves two main purposes: 1) to investigate the neutronic performance of pebble type fuel within the TMSR-SF1, and 2) to conduct a preliminary comparison between pebble coordinate generation methods. The first method of coordinate generation, the Discrete Element Method (DEM), is a particle-tracking model which accounts for inter-particle forces. While this method generates packing distributions closer to real-world scenarios, it is computationally intense. The alternative method analyzed is a mathematical model (MM), which fills arbitrary domains through simple geometric rules on the addition of particles. This method, while less realistic, generates coordinates significantly faster. Afterwards, fuel pebble coordinates from both methods are utilized to generate inputs for high-fidelity neutronics modelling. The results of these simulations, with the aid of various tools within Python, allowed for the neutronic analysis of the core, specifically when considering the eigenvalues of each coordinate set, and the fission power distribution within the fuel pebbles. It was found that the packing fraction in the axial direction to be consistent within the MM coordinate generation method, and the general trends similar between it and DEM-generated coordinates. Additionally, the eigenvalues of the simulated core were found to be proportional to the number of pebbles within the core. Finally, the fission power distribution of the cores was found to be qualitatively consistent both within many sets of MM-generated coordinates, and in comparisons of the two coordinate generation methods.
