Numerical Calculation Scheme of Neutronics-Thermal-Mechanical Coupling in Solid State Reactor Core Based on Galerkin Finite Element Method

Abstract

It is of practical significance to study the multi-physical processes of solid state nuclear systems for device design, safety analysis, and operation guidance. This system generally includes three multi-physical processes: neutronics, heat transfer, and thermoelasticity. In order to analyze the multi-physical field behavior of solid state nuclear system, it is necessary to analyze the laws of neutron flux, temperature, stress, and other physical fields in the system. Aiming at this scientific goal, this paper has carried out three aspects of work: (1) Based on Galerkin’s finite element theory, the governing equations of neutronics, heat transfer, and thermoelasticity have been established; (2) a neutronics-thermal-mechanical multi-physical finite element analysis code was developed and verified based on benchmark examples and third-party software for multi-physical processes; (3) for a solid state nuclear system with a typical heat pipe cooled reactor configuration, based on the analysis code developed in this work, the neutronics-thermal-mechanical coupling analysis was carried out, and the physical field laws such as neutron flux, temperature, stress, etc., of the device under the steady-state operating conditions were obtained; and (4) finally, the calculation results are discussed and analyzed, and the focus and direction of the next work are clarified.

Generalized Thermoelastic Heat Conduction Model Involving Three Different Fractional Operators

“…The instant time parameter t presents a weak effect on the thermal stresses on the surface of the medium. Indeed, the value of 𝜎 𝜑𝜑 is almost equal to -0.45 on the surface of the solid sphere and the value of 𝜎 𝑟𝑟 is equal to 0 which is compatible with the mechanical boundary condition (28). Thermal stress may have detrimental effects on the performance of some thermoelastic devices if thermomechanical processes are unable to control rapid increases in core temperature.…”

“…It is obvious from Fig. 4 that the graph of 𝜎 𝑟𝑟 for different models starts with a zero value at the surface of the medium, achieving the boundary condition (28), then, it decreases rapidly with decreasing 𝑟 to attain a negative minimum value (near 𝑟 = 1.8) and finally increases gradually with decreasing 𝑟 until it reaches the steady-state.…”

“…Besides, the conditions ( 27) and (28), in the transform field, take the forms 𝜃 ̅ (𝑎, 𝑠) = 𝜃 0 𝑠 , 𝜎 ̅ 𝑟𝑟 (𝑎, 𝑠) = 0 (54) Substituting Eqs. ( 49) and ( 52) into the formulas of Eq.…”

“…In aviation [21][22][23][24][25], the high speed of the aircraft causes aerodynamic heating which firstly leads to high thermal stress and secondly weakens the airframe. In the field of nuclear sciences [26][27][28][29], the design and operation of nuclear reactors are affected by the exceptionally high temperatures they generate. Besides, research in the domain of thermoelasticity becomes growingly important concerning the efficacy analysis of rocket engine technology [30], spacecraft technologies, Laser machining [31], the mechanics of steam turbines [32][33][34] and in ship construction where moderate thermal stresses frequently cause ships to crack.…”