The method of modular characteristic direction probabilities in MPACT

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

OSTI ID:22212845

Liu, Z. ^[1]; Kochunas, B.; Collins, B.; Downar, T. ^[2]; Wu, H. ^[1]

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

The method of characteristic direction probabilities (CDP) is based on a modular ray tracing technique which combines the benefits of the collision probability method (CPM) and the method of characteristics (MOC). This past year CDP was implemented in the transport code MPACT for 2-D and 3-D transport calculations. By only coupling the fine mesh regions passed by the characteristic rays in the particular direction, the scale of the probabilities matrix is much smaller compared to the CPM. At the same time, the CDP has the same capacity of dealing with the complicated geometries with the MOC, because the same modular ray tracing techniques are used. Results from the C5G7 benchmark problems are given for different cases to show the accuracy and efficiency of the CDP compared to MOC. For the cases examined, the CDP and MOC methods were seen to differ in k{sub eff} by about 1-20 pcm, and the computational efficiency of the CDP appears to be better than the MOC for some problems. However, in other problems, particularly when the CDP matrices have to be recomputed from changing cross sections, the CDP does not perform as well. This indicates an area of future work. (authors)

• Research Organization: American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
• OSTI ID: 22212845
• Country of Publication: United States
• Language: English

Related Subjects

97 MATHEMATICS AND COMPUTING
ACCURACY
COLLISION PROBABILITY METHOD
COMPARATIVE EVALUATIONS
CROSS SECTIONS
GEOMETRY
MATRICES
PROBABILITY