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Vectorization methods development for a new version of the KENO-V. a criticality safety code

Journal Article · · Nuclear Science and Engineering; (United States)
OSTI ID:5101424
;  [1];  [2]
  1. Oak Ridge National Lab., TN (United States)
  2. Univ. of Tennessee, Knoxville, TN (United States). Nuclear Engineering Dept.

The object of this research project is to develop a vectorized version of the KENO-V. a criticality safety code, benchmark it against the original version of the code, and determine its speedup factor for various classes of problems. The current generation of supercomputers is equipped with vector processors that allow the same operation to be simultaneously performed on a string of data. Unfortunately, the Monte Carlo algorithm used in KENO-V.a, which tracks particles individually, cannot utilize these vector processors. A new Monte Carlo algorithm that would efficiently utilize the vector processors currently used in computers is needed. The algorithm developed for the vectorized version of KENO-V. a is an event-based, stack-driven, all-zone, implicit-stack Monte Carlo algorithm. This algorithm divides the particles into one of four main stacks: free-flight, inward crossing, outward crossing, or collision. A fifth stack, kill, contains all particles that have either leaked from the system or have been terminated by Russian roulette. This approach minimizes data transfer between stacks and optimizes the vector length, thus maximizing the speedup. For the 25 benchmark problems, speedup factors ranging from 1.8 to 5.7 relative to the optimized scalar version of KENO-V.a were obtained. Problem geometry, material composition, and the number of histories per generation - all have significant effects on the speedup factor of a problem.

DOE Contract Number:
AC05-84OR21400
OSTI ID:
5101424
Journal Information:
Nuclear Science and Engineering; (United States), Journal Name: Nuclear Science and Engineering; (United States) Vol. 116:3; ISSN NSENAO; ISSN 0029-5639
Country of Publication:
United States
Language:
English