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NS Savannah open house for National Maritime Day
On Sunday, May 17, in Baltimore, Md., there will be an open house on the NS Savannah to commemorate National Maritime Day. The Savannah acted as a passenger and cargo ship from 1962 to 1970, serving as a floating ambassador for President Eisenhower’s Atoms for Peace program and, more broadly, for the safe and peaceful uses of nuclear power.
Paul Seurin, Koroush Shirvan
Nuclear Science and Engineering | Volume 200 | Number 3 | March 2026 | Pages 574-605
Research Article | doi.org/10.1080/00295639.2025.2488702
Articles are hosted by Taylor and Francis Online.
Optimizing the fuel cycle cost through the optimization of nuclear reactor core loading patterns (LPs) involves multiple objectives and constraints, leading to a vast number of candidate solutions that cannot be explicitly solved. To advance the state of the art in core reload patterns, we have developed methods based on deep Reinforcement Learning (RL) for both single- and multi-objective optimization. Our previous research laid the groundwork for these approaches and demonstrated their ability to discover high-quality patterns within a reasonable time frame. On the other hand, Stochastic Optimization (SO) approaches are commonly used in the literature, but there is no rigorous explanation that shows which approach is better in which scenario. In this paper, we demonstrate the advantage of our RL-based approach, specifically using Proximal Policy Optimization (PPO) against the most commonly used SO-based methods: Genetic Algorithm, Parallel Simulated Annealing with mixing of states, and Tabu Search, as well as an ensemble-based method, i.e. the Prioritized replay Evolutionary and Swarm Algorithm. We found that the LP scenarios derived in this paper are amenable to a global search to identify promising research directions rapidly but then need to transition into a local search to exploit these directions efficiently and prevent getting stuck in local optima. PPO adapts its search capability via a policy with learnable weights, allowing it to function as both a global search method and a local search method. Subsequently, we compared all algorithms against PPO in long runs, which exacerbated the differences seen in the shorter cases. Overall, the work demonstrates the statistical superiority of PPO compared to the other considered algorithms.