Measurement of prompt neutron decay constant and large subcriticality by the Feynman-. alpha. method

Journal Article · Mon Jan 01 04:00:00 EST 1990 · Nuclear Science and Engineering; (USA)

DOI:https://doi.org/10.13182/NSE104-53· OSTI ID:6978443

Misawa, T ^[1]; Shiroya, S; Kanda, K ^[2]

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1. Nagoya Univ. (Japan)
2. Kyoto Univ. (Japan)

The Feynman-{alpha} experiments have been carried out using light-water-moderated and -reflected cores loaded with highly enriched uranium fuel at the Kyoto University critical assembly. An experimental technique using a multichannel scaler was developed to improve the accuracy of measurement and to shorten measuring time. Then, the {beta}{sub eff}/l values of single and coupled cores with different neutron spectra were measured to demonstrate the capability of the present technique for measuring the prompt neutron decay constant {alpha}. Moreover, the Feynman-{alpha} method was applied to measuring large subcriticalities. Through these experiments, it is found that the present technique greatly improves the accuracy of {alpha} measurement, and the one-point reactor approximation is applicable to a tightly coupled core. It is also found that the subcriticality down to approximately {minus} 35 $ can be measured by this method if the position of the neutron detector is chosen carefully, and the present Feynman-{alpha} method can be applied to a subcriticality monitoring system.

• OSTI ID: 6978443
• Journal Information: Nuclear Science and Engineering; (USA), Journal Name: Nuclear Science and Engineering; (USA) Vol. 104:1; ISSN 0029-5639; ISSN NSENA
• Country of Publication: United States
• Language: English

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