A numerical simulation method for molten material behavior in nuclear reactors

Validation of free-convective heat transfer analysis with JUPITER to evaluate air-cooling performance of fuel debris in dry method

“…All of those numerical analyses series are going to perform with JUPITER. In our previous works, JUPITER was validated for singe-phase flow, multi-phase flow, solid boundary in flow, solidification and those composite phenomena by comparing with benchmark tests and VULCANO (Journeau et al, 2006) experimental results (Yamashita et al, 2017a). Those comparisons proved that JUPITER results were in agreement with those benchmark tests and the VULCANO results.…”

“…In order to reduce those unknown parameters, Japan Atomic Energy Agency (JAEA) has evaluated the air-cooling performance of the fuel debris in the dry method by using JUPITER (Yoshida et al, 2016). JUPITER is originally developed for the phenomenological simulation of melt relocation behaviors of the reactor core in the RPV and the PCV (Yamashita et al, 2017a(Yamashita et al, , 2017b(Yamashita et al, , 2017c. The code is a multi-phase, multi-component thermal-hydraulics simulation method based on computational fluid dynamics.…”

Application of a Preconditioned Chebyshev Basis Communication-Avoiding Conjugate Gradient Method to a Multiphase Thermal-Hydraulic CFD Code

“…In the JUPITER code [6], thermal-hydraulics of the molten material in nuclear reactors is described by the equations of continuity, Navier-Stokes, and energy, assuming Newtonian and incompressible viscous fluids. The dynamics of gas, liquid, and solid phases of multiple components consisting of fuel pellets, fuel cladding, the channel box, the absorber, reactor internal components, and the atmosphere are described by an advection equation of the volume of fluid (VOF) function.…”

“…In order to resolve this issue at mathematics or algorithm levels, in Refs. [3,4], we have introduced communication-avoiding (CA) Krylov methods to a fusion plasma turbulence code GT5D [5] and a multiphase thermal-hydraulic CFD code JUPITER [6].The implicit solver in the GT5D is well-conditioned, and the communicationavoiding general minimum residual (CA-GMRES) method [7] was stable for large CA-steps s > 10. On the other hand, the Poisson solver in the JUPITER is ill-conditioned, and the convergence of the left-preconditioned communicationavoiding conjugate gradient (P-CACG) method [7] was limited for s ≤ 3.…”

“…In order to resolve this issue at mathematics or algorithm levels, in Refs. [3,4], we have introduced communication-avoiding (CA) Krylov methods to a fusion plasma turbulence code GT5D [5] and a multiphase thermal-hydraulic CFD code JUPITER [6].…”