Development Status of the PEBBLES Code for Pebble Mechanics: Improved Physical Models and Speed-up

摘要: PEBBLES is a code for simulating the motion of all pebbles in pebble bed reactor. Since reactors are packed randomly and not precisely placed, location fuel elements reactor deterministically known. Instead, when determining operating parameters can be simulated stochastic locations found. The output information relevant other simulations such as positions reactor, packing fraction change an earthquake, velocity profiles created by recirculation. goal this level three milestone was to speedup through implementation on massively parallel computer. Work has resulted speeding up both single processor version creation new PEBBLES. Both running capability have improved since fiscal year start. hybrid MPI/OpenMP run increasingly common cluster hardware profile that combines nodes with multiple processors share memory networked together. OpenMP portions usemore » Open Multi-Processing shared processing model split task across node shares memory. Message Passing Interface (MPI) portion uses messages communicate between different over network. following wall clock speed NGNP-600 sized runs 1.5 times faster compared at beginning year. This primarily due static friction described report. When 64 processors, 22 current version. using 88 23 achieved. improvements combine make more capable useful simulation report details effects work done course year.« less