Preliminary design study on the concept of nanofluidic molten salt reactor

Abstract

Molten salt reactor (MSR) is the one of the most promising reactor types among Gen-IV reactors due to its intrinsic safety features and sustainability. For the liquid-fueled MSR, lots of efforts on the development of molten salt reactor technologies had been conducted by Oak Ridge National Laboratory of USA in 1950s, and it was demonstrated successfully by molten salt reactor experiment. Recently, this concept has been reconsidered as a breakthrough of the current nuclear safety and waste issue. Most of the MSR designs reported until now adopt the fuel salt of eutectic formation with fertile material such as uranium, plutonium, or TRU with fluoride or chloride salt, which enables the fuel salt as homogeneous state as possible. However, due to the complexity of fuel salt composition during depletion giving uncertainties of the thermophysical properties as well as bad thermal and transport properties such as thermal conductivity, specific heat, design and analysis of molten salt reactor and related systems should consider these carefully. With aims of the developing technologies regarding the nanoparticle and nanofluid, molten salt with fuel nanoparticle has been considered as one of the possible options for the molten salt reactor concept as advanced heat transfer fluid or advanced coolant itself. Starting with this idea, this paper introduces new concept of molten salt reactor, nanofluidic molten salt reactor and deals with the preliminary study on the reactor design features with heat transfer enhancement of coolant using in-house code for the integral analysis of molten salt reactor; neutronics and thermal-hydraulic coupled solver in Multiphysics toolkit OpenFOAM. And then, development of the solver will be briefly described including Multiphysics modeling of nanofluidic fuel salt and system, and sensitivity analysis technique using adjoint-based method. Especially for the decay heat removal system for drain tank of liquid fueled MSR, the feasibility of the molten salt nanofluid application is investigated.