Monte Carlo simulation method for active critical device in approximate critical process

Abstract

The invention relates to a Monte Carlo simulation method for an active critical device in an approximate critical process, which is suitable for the field of neutronics physical analysis of a nuclearcritical device with an external neutron source. According to the invention, the method comprises the steps: decomposing a continuous neutron transport process into successive generations of analog calculation, and according to successive generations of system neutron effective proliferation factors and successive generations of physical quantity statistical counting, and carrying out the weightedsummation to obtain final calculation results of physical quantities such as nuclear critical device power level and neutron flux distribution are obtained. According to the method, Monte Carlo simulation of the transport process of the external neutron source in the approaching critical process of the nuclear critical device is achieved, and the situation that infinite transport calculation of the external neutron source of a certain generation is not terminated due to randomness of the Monte Carlo method is avoided; the Monte Carlo simulation method for the neutron transport process of theactive critical device is advanced and has engineering feasibility.

Description

technical field [0001] The invention relates to a neutronics physical analysis technology for a nuclear critical device, in particular to a Monte Carlo simulation method for an active critical device in the process of approaching criticality. Background technique [0002] When carrying out nuclear criticality experiments, in order to better monitor the physical state of the nuclear criticality device, it is usually necessary to configure a certain intensity of external neutron sources in the nuclear criticality device, and at the same time arrange neutron detectors at different positions. The neutron flux distribution and its change rate are used to infer the characteristic parameters of the nuclear criticality device such as subcriticality and reactivity introduction rate, so as to carry out nuclear criticality-related experiments safely and efficiently. [0003] For this reason, in the design of nuclear criticality devices, it is necessary to calculate and analyze the neut...

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Problems solved by technology

Computational analysis usually adopts three-dimensional Monte Carlo program. During calculation and analysis, the following problems are often encountered: the system itself k eff Larger, for example, when it exceeds 0.99, due to the randomness of the Monte Carlo method itself, there is a greater probability that the infinite transport calculation of a certain external neutron source will not terminate, and it is difficult to carry out the effective neutron transport process. Luo simulated the situation, so that the neutron flux distribution data of each detection point could not be obtained, which brought great difficulties in the range design of neutron detectors at each detection point, and the reference of flux values ​​during debugging and operation.

[0007] Judging from the survey situation, the relevant research is mostly used for experimental measurement and analysis, and there are relatively few neutronics physical analysis and simulations in the process of approaching the critical process of the critical device with an external neutron source, and the system itself eff When it exceeds 0.99, there will be a problem that the infinite transport calculation of a certain generation of neutron sources will not be terminated during the simulation of the Monte Carlo program, and it is difficult to carry out an effective neutron transport process. No researcher has given a feasible solution

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