A New Numerical Nuclear Reactor Neutronics Code SHARK

In order to establish the next-generation reactor physics calculation method based on the numerical nuclear reactor technology and realize high-fidelity modeling and calculation, a new numerical nuclear reactor neutronics code SHARK is developed. The code is based on the direct transport method with construct solid geometry (CSG) method, advanced subgroup resonance method, direct transport MOC method in rectangle and hexagonal geometry, large-scale parallel, and CMFD acceleration method. The C5G7, macro BEAVRS and VERA benchmarks are verified to show the accuracy of the code and method. Numerical results show good accuracy and calculation performance of SHARK, and the direct transport method can be adopted on numerical nuclear reactor calculation.

Preface

List of International Conference On High Temperature Reactor Technology 2021, Editorial Board And Reviewers, Design And Layout are available in this pdf.

Magneto-convective fluctuation during downward flow of liquid metal in a heated pipe in a transverse magnetic field

An imposed strong magnetic field suppresses turbulence and profoundly changes the nature of the flow of an electrically conducting fluid. We consider this effect for the case of mixed convection flows in pipes and ducts, in which unique regimes characterized by extreme temperature gradients and high-amplitude fluctuations (the so-called magnetoconvective fluctuations) have been recently discovered. The configuration is directly relevant to the design of the liquid-metal components of future nuclear fusion reactors. This work presents the general picture of the flow transformation emerging from the recent numerical studies (DNS - Direct Numerical Simulation), illustrates the key known facts, and outlines the remaining open questions. Implications for fusion reactor technology and novel experimental and numerical methods are also discussed.

Thermodynamic Assessment of the AF–CrF3 (A = Li, Na, K) and CrF2–CrF3 Systems

Understanding the corrosion mechanisms and the effect of corrosion products on the basic properties of the salt (e.g., melting point, heat capacity) is fundamental for the safety assessment and durability of molten salt reactor technology. This work focused on the thermodynamic assessment of the CrF2−CrF3 system and the binary systems of chromium trifluoride CrF3 with alkali fluorides (LiF, NaF, KF) using the CALPHAD (computer coupling of phase diagrams and thermochemistry) method. In this work, the modified quasi-chemical model in the quadruplet approximation was used to develop new thermodynamic modelling assessments of the binary solutions, which are highly relevant in assessing the corrosion process in molten salt reactors. The agreement between these assessments and the phase equilibrium data available in the literature is generally good. The excess properties (mixing enthalpies, entropies and Gibbs energies) calculated in this work are consistent with the expected behaviour of decreasing enthalpy and Gibbs energy of mixing with the increasing ionic radius of the alkali cations.

Westinghouse eVinci™ Heat Pipe Micro Reactor Technology Development

Westinghouse Electric Co. is developing the eVinci™ Micro-Reactor to provide grid resiliency for strategic infrastructure, deliver power for remote applications and support growing space fission power needs. At the heart of the reactor technology are alkali metal heat pipes. Alkali metal heat pipes replace the complex primary coolant systems necessary for other high temperature reactor designs with a safe, simple system that has no moving parts. The heat pipe reactor relies on alkali metal phase change resulting in superior temperature uniformity within the reactor core and elimination of the need for a pressurized primary system containment vessel. An array of closed heat pipes provides redundancy of the primary heat removal path and enables a modular core design that supports reduced scale testing. Westinghouse has commissioned a dedicated facility aimed at developing heat pipe technology for commercial nuclear applications. The efforts build upon the success of the KRUSTY nuclear demonstration and solves some of the challenges associated with commercial micro-reactors that require use of low enriched uranium (LEU). Westinghouse has completed first of a kind demonstration testing of high-performance alkali metal heat pipes using Iron, Chromium, Aluminum (FeCrAl) alloys. This technology enables a LEU micro-reactor core in addition to an open-air Brayton thermodynamic power conversion cycle.