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Tada, Kenichi; Endo, Tomohiro*
EPJ Web of Conferences, 284, p.14013_1 - 14013_4, 2023/05
Times Cited Count：0 Percentile：0.21(Nuclear Science & Technology)The self-shielding effect in the unresolved resonance region has a large impact on the fast- and intermediate-spectrum reactors. The probability table method is widely used for continuous-energy Monte Carlo calculation codes to treat the effect. In this method, a table provides the probability distribution of the cross-section for a nuclide in the given energy grid points. The table is generated by averaging with a lot of "ladders" which represent pseudo resonance structures. Though many nuclear data processing codes require the number of ladders as an input parameter to generate the probability table, an optimal number of ladders has not been investigated. Our previous study revealed that the suitable number of ladders depends on the nuclide and its resonance parameters. This result indicates that it is very difficult for users to find the optimal number of ladders. We developed the calculation method of the statistical uncertainty for the probability table generation.
Tada, Kenichi
Proceedings of International Conference on the Physics of Reactors; Transition To A Scalable Nuclear Future (PHYSOR 2020) (USB Flash Drive), 8 Pages, 2020/03
The probability table is widely used for continuous energy Monte Carlo calculation codes to treat the self-shielding effect in the unresolved resonance region. The ladder method is used to calculate the probability table. This method generates a lot of pseudo resonance structures using random numbers based on the averaged resonance parameters. The probability table affects the ladder number. i.e., number of pseudo resonance structures. The ladder number has large impact on the generation time of the cross section library. In this study, the appropriate ladder number is investigated. The probability table of all nuclides prepared in JENDL-4.0 is used to investigate the appropriate ladder number. The comparison results indicate that the differences of the probability table are enough small when the ladder number is 100.
Tada, Kenichi
Proceedings of Reactor Physics Paving the Way Towards More Efficient Systems (PHYSOR 2018) (USB Flash Drive), p.2929 - 2939, 2018/04
JAEA develops a new nuclear data processing system FRENDY. We investigated all processing methods and we focused on the probability table generation using the ladder method which is adopted in the PURR module in NJOY. To improve the probability table generation, the more sophisticated method was introduced in the calculation methods of the Chi-Squared random numbers and the complex error function. We also investigated the appropriate ladder number. To investigate the impact of the difference of the complex error function calculation method, the K
values of the benchmark experiments with the probability tables by the both methods were compared. The calculation results indicated that the appropriate ladder number is 100 and the difference of the calculation methods of the Chi-Squared random numbers and the complex error function has no significant impact on the neutronics calculation.
Tada, Kenichi; Nagaya, Yasunobu
no journal, ,
JAEA has been developing the nuclear data processing code FRENDY (FRom Evaluated Nuclear Data librarY to any application). In this presentation, construction of the probability table in the unresolved resonance region is described.
Tada, Kenichi
no journal, ,
JAEA started to develop the new nuclear data processing system FRENDY. FRENDY can generate the ACE (A Compact ENDF) file without NJOY module and it is implemented not only NJOY's nuclear data processing method but also FRENDY original method. In this presentation, the impact of the difference of nuclear data processing method on the k-effective value is investigated.
Nagaya, Yasunobu; Hagura, Hiroyuki*
no journal, ,
In order to build the criticality safety database for fuel debris, a Monte Carlo Solver Solomon has been under development. The probability table method has been implemented into Solomon to treat the self-shielding effect in the unresolved resonance region correctly. The implementation has been verified with the calculation of effective multiplication factors for simple geometry systems.
Tada, Kenichi
no journal, ,
To improve the probability table generation, the more sophisticated method was introduced in the calculation methods of the Chi-Squared random numbers and the complex error function. We also investigated the impact of the ladder number on the probability table. We confirm that the calculation speed of new method is 20% faster than that of the old method.
Tada, Kenichi
no journal, ,
The ladder number has large impact on the probability table generation time. In this paper, we investigate the appropriate ladder number to generate probability table. The calculation results indicate that the appropriate ladder number to generate probability table is 100.
Tada, Kenichi; Endo, Tomohiro*
no journal, ,
Probability table is used for consideration of self-shielding effect in the unresolved resonance region. The probability table is calculated by the Monte Carlo calculation method. However, statistical error of the probability table is not calculated. In this study, we developed statistical error calculation method for probability table generation and implemented this method to FRENDY.
