Calculation method of minimum nuclear critical accident radiation source item

Abstract

The invention relates to a minimum nuclear critical accident radiation source item calculation method, which screens out a critical accident scene from various mechanisms of possible critical accidents, and further optimizes and considers a source item by adopting a method of simplifying a geometric model. Aiming at the problem that normalization factors of a neutron source item and a photon source item are different when a critical accident radiation source item is analyzed by a three-dimensional Monte Carlo program, the neutron source item and the photon source item are respectively normalized by adopting a three-time differential calculation mode through technologies of writing a fission volume source, reading the fission volume source, closing a fission cross section, generating a switch for fission photons and the like; therefore, the problem of source item analysis difficulty in a non-critical state is solved. According to the method, the requirement for reasonable analysis of the minimum nuclear critical accident radiation source item in arrangement design and threshold setting of a nuclear critical accident alarm system is met, and the method is an advanced minimum nuclearcritical accident radiation source item calculation method with engineering feasibility.

Description

technical field [0001] The invention relates to a nuclear criticality safety analysis technology for fissile materials outside a reactor, in particular to a calculation method for a minimum nuclear criticality accident radiation source item, which is used for layout optimization and threshold value selection of a nuclear criticality accident alarm system. Background technique [0002] The nuclear criticality accident alarm system is used to timely detect nuclear criticality accidents and trigger alarms to urge personnel to evacuate to prevent radiation exposure after the first peak of nuclear criticality accidents; Measure and mitigate to minimize the consequences of nuclear criticality accidents. Since the radiation exposure after the first peak is still large, the rapid evacuation response triggered by the nuclear criticality accident alarm system plays an important role in reducing the radiation dose of the operators. [0003] In the design of spent fuel reprocessing pla...

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Problems solved by technology

In the design of the post-processing intermediate test plants that have been built in my country, due to the limitation of calculation means and the lack of design experience, the simplified treatment of single-equipment and one-dimensional calculation has been adopted, and no detailed analysis and research has been carried out on the radiation source item of the minimum nuclear criticality accident.

[0006] Judging from the research and design of nuclear criticality accident alarm systems at home and abroad, the calculation of the radiation source term of the minimum nuclear criticality accident is based on the definition of the minimum nuclear criticality accident, but how to establish the calculation model of the radiation source term of the minimum nuclear criticality accident And how to calculate the neutron and photon source items separately, there is no published detailed and systematic calculation and analysis method for reference

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