A method for inverse dynamic measurement of subcriticality without space effect

Abstract

The invention provides a subcritical degree reverse dynamic measuring method free of a space effect. Compared with other methods, the method is characterized in that subcritical degree online measurement free of the influence of the space effect is achieved, wherein a stationary source mode is selected to work out space positions with the neutron-flux density normalization shape function unchanged after the state of a reactor is changed to arrange detectors; the reference subcritical degree of a subcritical reactor and the neutron-flux density under the condition that a stable external source is available are measured based on a pulse neutron source method or a source jerk method, and an external neutron source item is scaled with a subcritical inverse dynamic formula; the subcritical degree is calculated on line according to time-sequence data read at the positions of the detectors. The method has the advantages that the influence of redistribution of the neutron-flux shape space is avoided when the subcritical degree is measured; the delay effect of delayed neutrons can be responded to; the subcritical degree can be measured online in real time regardless of low power or high power.

Description

technical field [0001] The invention relates to the technical field of measuring the subcriticality of a subcritical system, in particular to an inverse dynamic measurement method for the subcriticality without space effect. Background technique [0002] The minimization of nuclear waste is a key issue for the sustainable development of nuclear fission energy. Accelerator-driven subcritical system (ADS) is a highly efficient nuclear waste transmutator and a key technology for solving nuclear waste. ADS consists of a medium-energy high-current proton accelerator, an exogenous neutron generating target and a subcritical reactor, and is a highly efficient nuclear waste transmutator (or incinerator). In ADS, the proton beam generated by the accelerator bombards the heavy metal target (such as liquid Pb or Pb-Bi alloy) in the subcritical reactor, causing a spallation reaction, and then generates neutrons to drive the subcritical through cascade reactions inside and outside the n...

AI Technical Summary

Problems solved by technology

The inverse dynamic method is relatively mature for critical reactors, and various reactivity instruments for reactors have been produced. The subcriticality measurement of subcritical systems driven by strong external sources, especially accelerator-driven subcritical reactors, needs to be solved for the application of inverse dynamics. Two problems: (1) the validity of the kinetic equation of the subcritical point; (2) the calibration and reference subcriticality measurement after the introduction of external sources;

[0037] The second problem is that it is necessary to calibrate the external source, and transform it into a deep subcritical measurement method, such as the pulsed neutron source method or the jump source method to accurately measure the reference subcritical degree ρ $ , and then based on the reference subcriticality and the detector position under the core containing a steady-state external source, the neutron flux density data p(0) is used to scale the size of the external source item: s=-p(0)βρ $

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