Method and system for evaluating melt fragmentation in sodium-cooled fast reactor (SFR)

A computer system, comprising:

• one or more processors;
• a memory;
• and
• one or more programs;
• wherein the one or more programs are stored in the memory, and are configured to cause, when executed by the one or more processors, the computer system to:
• (S1) read and pre-process information of each of a plurality of particles, comprising initial position, velocity, temperature, pressure, phase, and particle bulk number;
• (S2) create a Link-list;
• determine distribution of the plurality of particles in a grid after the pre-processing in step (S1);
• search for neighboring particles with a corresponding cutoff radius, and store the neighboring particles;
• determining a free surface;
• optimize the distribution of the plurality of particles using an optimized particle-shifting scheme;
• (S3) according to an optimized distribution obtained in step (S2), perform discretization on a temperature discretization operator using a high-order discretization model in combination with a heat transfer and phase transition model;
• re-calculate temperature, enthalpy and liquid phase volume fraction of each of the plurality of particles in a computational domain according to a heat conduction equation;
• and update physical parameters of the plurality of particles according to the temperature and the liquid phase volume fraction in combination with an equation of state (EOS);
• (S4) smooth density and viscosity of the plurality of particles with updated physical parameters obtained in step (S3);
• (S5) calculate a viscous force of individual particles according to smoothed density and viscosity of the plurality of particles obtained in step (S4) in combination with velocity;
• calculate a surface tension of the plurality of particles according to an inter-particle free energy model;
• make explicit correction to the velocity and a position of each of the plurality of particles based on the viscous force, the surface tension and gravity to obtain an intermediate velocity and an intermediate position of each of the plurality of particles at each time step;
• and
• (S6) solve a pressure Poisson equation according to a least-square moving particle semi-implicit (LSMPS) method to implicitly solve the pressure of each of the plurality of particles;
• update the velocity and the position of each of the plurality of particles based on the pressure, and obtain a velocity and a position of each of the plurality of particles at an n+1th time step in combination with the intermediate velocity and the intermediate position obtained in step (S5);
• search for a particle bulk according to Passively Moving Solid (PMS) correction to acquire center-of-gravity (CG) information of the particle bulk;
• update a velocity and a position of each particle in the particle bulk according to calculated velocity and calculated angular velocity of the particle bulk, so as to complete calculation at each time step in turn, thereby generating real-time melt fragmentation data of the SFR comprising the number of fragments, a maximum fragment mass and a maximum fragment size;
• generate a visual dynamic graph of melt fragmentation in real time based on the real-time melt fragmentation data;
• and monitor and locate for a user, conditions of the melt fragmentation inside the SFR in real time based on the visual dynamic graph.