Experimental validation of unique combination numbers for third- and fourth-order neutron correlation factors of zero-power reactor noise

DOI IR HANDLE Web Site 5 Citations 21 References Open Access

Abstract

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.

Journal

Citations (5)*help

See more

References(21)*help

See more

Related Projects

See more

Keywords

Details 詳細情報について

Report a problem

Back to top