Nuclear Science and Engineering

The analysis of molten salt samples benefits significantly from using small, uniform samples. One such analysis technique that requires these samples is the diamond-based microfluidic alpha spectrometer (DiMAS), which relies on depositing very small quantities of molten fluoride salts on its surface to enable high-resolution alpha spectrometry. To facilitate this, a pneumatic droplet generator fo…

Advances in nuclear technology and modern medicine have driven the development of a variety of radiopharmaceuticals, labeled with medical isotopes, that play an important role in the treatment and diagnosis of various diseases. With the decommissioning of high-flux nuclear reactors, high-energy proton-induced spallation reactions on thorium are now becoming an alternative and the most commonly us…

Power reactor noise, which describes the fluctuations of the neutron flux around its mean value, is a valuable tool in nuclear reactor monitoring. In recent years, several numerical tools have been developed to solve the Fourier-transformed Boltzmann equation that underpins neutron noise theory in the frequency domains. Among the proposed computational strategies, Monte Carlo methods are motivate…

The Jezebel plutonium critical assembly, operated from 1954 to 1977, has been a benchmark for validating nuclear data, particularly for fast 239Pu fission, over the past 70 years. However, since its disassembly decades ago, there have been issues with Jezebel’s legacy, including incomplete documentation, limited opportunities for long-term system parameter observations, and a lack of means to tes…

Resonance self-shielding in the unresolved resonance region (URR) is driven by the variance of the cross-section distribution, which probability tables are designed to represent. This paper identifies two mechanisms by which standard nuclear data processing distorts this variance. First, the multiplicative normalization used to enforce mean consistency between the probability table and the evalua…

The Chebyshev rational approximation method (CRAM) computes the matrix exponential by applying the best rational approximation (of order k) to ex on (−∞,0] directly to the matrix. Published CRAM coefficients are available up to order 48. Applications such as coupled depletion-transport calculations, extended-precision arithmetic, nuclear safeguards verification, or nuclear arms control and disarm…

This paper evaluates the accuracy and computational performance of the RAPID (real-time analysis for particle transport and in-situ detection) code system and its newly developed physics-informed artificial intelligence (AI) extension, RAPID-AI, for whole-core reactor simulations. RAPID is based on the multistage response function transport (MRT) methodology, a hybrid deterministic Monte Carlo ap…

Lithium plays a dual role in deuterium-tritium (D-T) fusion systems by enabling tritium breeding in blankets and providing an efficient heat removal medium in liquid-metal components. However, most existing investigations treat neutronic behavior, jet thermohydraulics, and feedback control as largely decoupled layers, and there is currently no compact analytical framework that simultaneously link…

The French nuclear energy landscape is currently experiencing a renewal, including innovative reactor designs. Among innovative reactor concepts, some use TRi-structural ISOtropic (TRISO) particle fuel. The implementation of such new fuel presents a challenge for nuclear criticality safety (NCS) assessment during operations in nuclear power plants, in manufacturing and reprocessing facilities, as…