2023-09-28T09:13:27Z
https://nagoya.repo.nii.ac.jp/oai
oai:nagoya.repo.nii.ac.jp:00027483
2023-01-16T04:19:17Z
320:321:322
Experimental validation of unique combination numbers for third- and fourth-order neutron correlation factors of zero-power reactor noise
Endo, Tomohiro
89827
Yamamoto, Akio
89828
Yamanaka, Masao
89829
Pyeon, Cheol Ho
89830
Reactor noise
Feynman-α method
higher-order neutron correlation
subcriticality
double factorial
bootstrap method
statistical error
covariance
KUCA
measurement
Zero-power reactor noise is useful for subcriticality measurements. Based on the nuclear reactor physics and the theory of neutron detection, this paper theoretically clarifies that the third- and fourth-order neutron correlation factors Y3 and Y4 can be expressed as functions of the second-order neutron correlation factor Y. In particular, if the neutron-counting gate width is sufficiently large, the saturation values Y3/Y^2 and Y4/Y^3 are almost equal to the unique combination numbers, ‘3’ and ‘15,’ for a source-driven subcritical system, where the subcriticality is less than 10,000 pcm. These unique combination numbers, ‘3’ and ‘15,’ for Y3/Y^2 and Y4/Y^3 were validated using actual zero-power reactor noise measurements carried out at the Kyoto University Criticality Assembly. In this study, the estimation of statistical errors and correlations between different gate widths owing to the bunching method was achieved by the moving block bootstrap method. For a sufficiently long measured reactor noise in a steady and unperturbed state, a statistical test for the evaluation of the critical state and the absolute measurement of subcriticality can be carried out by statistically quantifying the difference between the measurement value of Y3/Y^2 and the unique combination number.
ファイル公開：2020/03/04
journal article
Taylor & Francis
2019-03-04
application/pdf
Journal of Nuclear Science and Technology
4
56
322
336
0022-3131
1881-1248
https://nagoya.repo.nii.ac.jp/record/27483/files/JNST56(4)_pp322-336_2019_rev1.pdf
eng
https://doi.org/10.1080/00223131.2019.1580625
This is an Accepted Manuscript of an article published by Taylor & Francis Group in Journal of Nuclear Science and Technology on 04/03/2019, available online: http://www.tandfonline.com/10.1080/00223131.2019.1580625.