Nuclear fuel burnup depth measuring device and method based on active neutron space intensity distribution

Abstract

The invention discloses a nuclear fuel burnup depth measuring device based on active neutron space intensity distribution and a measuring method thereof. The measuring device comprises a compact D-D neutron source, a neutron moderator and a gamma shielding body which wrap the D-D neutron source in sequence, a conical neutron collimation hole channel formed in the neutron moderator, and a thermal neutron image detector system connected with the conical neutron collimation hole channel. The conical neutron collimation pore channel is arranged at a certain distance above the compact D-D neutron source and is used for obtaining quasi-parallel neutron beams. Because the thermal neutrons and different elements in the nuclear fuel have different reaction sections, the neutron fluxes of the conical neutron collimation pore channels penetrating through the nuclear fuel element sample are different in space, and the burnup depth space distribution and the average burnup of the nuclear fuel element are measured according to the established response model of the thermal neutron transmission intensity and the fuel burnup. The method belongs to a novel nuclear fuel burnup non-destructive analysis technology, and has the characteristics of rapidness, accuracy, no damage and good spatial resolution.

Description

technical field [0001] The invention belongs to the technical field of non-destructive detection of high radioactive nuclear materials, and in particular relates to a nuclear fuel burnup depth measurement device and measurement method based on active neutron spatial intensity distribution. Background technique [0002] The fuel element is the core component of a nuclear reactor, and its performance index directly reflects the safety and economy of the reactor. The burnup marks the degree of nuclear fuel consumption during the operation of the reactor. The deeper the burnup, the more fully the nuclear fuel is used, which can reduce the cost of power generation. But the fuel consumption cannot be infinitely deepened, otherwise the chain reaction will be difficult to maintain. Accurate measurement of the burnup depth of reactor fuel elements has a great effect on improving reactor efficiency and economy, and is of great significance in the fields of nuclear power plants, burnup...

AI Technical Summary

Problems solved by technology

[0005] The problems existing in the prior art are: the destructive analysis (DA) technique takes a long time period to measure the burnup depth of the irradiated nuclear fuel, has high environmental requirements for the measurement, and has complicated measurement procedures. The high-resolution gamma spectrometry method of nuclear fuel burnup depth after irradiation is limited by low measurement efficiency and difficulty in distinguishing complex gamma spectra, resulting in low measurement accuracy of nuclear fuel burnup depth; The passive neutron measurement method of nuclear fuel burnup depth after irradiation is limited by neutron detectors with high detection efficiency, and the neutron intensity decreases exponentially with cooling time, making it difficult to correct the measurement data

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