Parallel 3-D method of characteristics in MPACT

Conference · Mon Jul 01 04:00:00 EDT 2013

OSTI ID:22212693

Kochunas, B.; Dovvnar, T. J. ^[1]; Liu, Z. ^[2]

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1. Department of Nuclear Engineering and Radiological Sciences, University of Michigan, 2200 Bonisteel, Ann Arbor, MI 48109 (United States)
2. School of Nuclear Science and Technology, Xi'an Jiaotong University, No. 28 Xianning West Road, Xi'an, Shaanxi 710049 (China)

A new parallel 3-D MOC kernel has been developed and implemented in MPACT which makes use of the modular ray tracing technique to reduce computational requirements and to facilitate parallel decomposition. The parallel model makes use of both distributed and shared memory parallelism which are implemented with the MPI and OpenMP standards, respectively. The kernel is capable of parallel decomposition of problems in space, angle, and by characteristic rays up to 0(104) processors. Initial verification of the parallel 3-D MOC kernel was performed using the Takeda 3-D transport benchmark problems. The eigenvalues computed by MPACT are within the statistical uncertainty of the benchmark reference and agree well with the averages of other participants. The MPACT k{sub eff} differs from the benchmark results for rodded and un-rodded cases by 11 and -40 pcm, respectively. The calculations were performed for various numbers of processors and parallel decompositions up to 15625 processors; all producing the same result at convergence. The parallel efficiency of the worst case was 60%, while very good efficiency (>95%) was observed for cases using 500 processors. The overall run time for the 500 processor case was 231 seconds and 19 seconds for the case with 15625 processors. Ongoing work is focused on developing theoretical performance models and the implementation of acceleration techniques to minimize the number of iterations to converge. (authors)

• Research Organization: American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
• OSTI ID: 22212693
• Country of Publication: United States
• Language: English

Related Subjects

97 MATHEMATICS AND COMPUTING
BENCHMARKS
COMPUTER CALCULATIONS
COMPUTER CODES
CONVERGENCE
EIGENVALUES
NEUTRON TRANSPORT
PARALLEL PROCESSING
PERFORMANCE
THREE-DIMENSIONAL CALCULATIONS