Abstract
This paper discusses the generation of temperature
majorant cross sections, the type of cross sections
required by two separate techniques related to Monte
Carlo neutron tracking, namely, the Dopplerbroadening
rejection correction (DBRC) and target motion sampling
(TMS) temperature treatment methods. In the generation of
these cross sections, the theoretically infinite range of
thermal motion must be artificially limited by applying
some sort of a cutoff condition, which affects both the
accuracy and the performance of the calculations. In this
paper, a revised approach for limiting thermal motion is
first introduced, and then, optimal cutoff conditions are
determined for both the traditional majorant, commonly
used in DBRC implementations and old implementations of
the TMS method, and the revised majorant. Using the
revised type of temperature majorant cross sections
increases the performance of the TMS method slightly, but
no practical difference is observed with the DBRC method.
It is also discovered that in ordinary reactor physical
calculations, the cutoff conditions originally adopted
from the SIGMA1 Dopplerbroadening code can be
significantly relieved without compromising the accuracy
of the results. By updating the cutoff conditions for
majorant generation, the CPU time requirement of Serpent
2.1.17 is reduced by 8% to 23% in TMS calculations and by
1% to 6% in problems involving DBRC.
Original language | English |
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Pages (from-to) | 209-223 |
Journal | Nuclear Science and Engineering |
Volume | 180 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2015 |
MoE publication type | A1 Journal article-refereed |
Keywords
- target tracking
- CPU time
- cut-off conditions
- majorant
- Monte Carlo neutron
- reactor physical calculation
- target motions
- temperature treatments
- thermal motion
- Monte Carlo methods