Title:
METHOD FOR MEASURING COMPOSITION, SUBCRITICALITY, DELAYED NEUTRON RATIO, NEUTRON GENERATION TIME, AND PROMPT NEUTRON LIFESPAN OF NUCLEAR FISSILE MATERIAL ON THE BASIS OF ONLY SIGNALS OF NEUTRON DETECTOR AND THE LIKE
Document Type and Number:
Japanese Patent JP2018159669
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a method and device using the method that allow reactivity to be properly measured even in a situation where information on an inner structure of a nuclear fuel body system such as, for example, a post-incident nuclear reactor, or an entire shape thereof is not obtainable.SOLUTION: Using that n(t)=αq(t)+nof an expression is established where the number of neutrons, to be detected by a neutron detector, at a time t in a nuclear fuel is denoted as n(t), the number of neutrons when the neutron remains stable after a change in reactivity and the like is denoted as n, a coefficient of subcriticality is denoted as α, and a weighted time differential n(t) of the number of neutrons n(t) is denoted as q(t), and a ratio of αq and n - n(a difference between n serving as a calculation rate deducting a noise component from a neutron detection signal and a value nat a stable time of the neutron stands at 1 regardless of the time, a delayed neutron ratio and a delayed neutron decay constant are determined.SELECTED DRAWING: Figure 1
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Inventors:
YAMANE YUICHI
Application Number:
JP2017057974A
Publication Date:
October 11, 2018
Filing Date:
March 23, 2017
Export Citation:
Assignee:
JAPAN ATOMIC ENERGY AGENCY
International Classes:
G21C17/00; G21C17/108
Attorney, Agent or Firm:
Nichimine International Patent Office