Burn-up measurement system for spent fuel assembly

Abstract

The invention discloses a gamma-spectrum detection system consisting of an antimony zinc cadmium detector and used for measuring burn-up of a spent fuel assembly. The system comprises a CZT detector, a digital multi-channel analyzer, a shielding aligner, a shield, a pressure-resistant sealing container and the like, wherein the shielding aligner is a cylinder; a conical groove is formed on an upper part of the shielding aligner; a movable slider is arranged in the conical groove; the movable slider is dragged by a step motor through a screw to move up and down; and the width of an alignment hole is controlled to be 0-5 mm. The system controls the width of the alignment hole by adjusting the movable slider so as to control a full-spectrum counting rate of a detected energy spectrum within a proper range and obtain relatively high measurement precision. Meanwhile, the measuring system is relatively compact and is favorable to be freely moved in a spent fuel assembly storage pool for in situ measurement.

Description

technical field [0001] The invention belongs to the technical field of gamma ray radiation measurement, in particular to a gamma spectrum detection system composed of cadmium zinc telluride detectors used for measuring the burnup of spent fuel assemblies. Background technique [0002] The non-destructive measurement methods of spent fuel burnup mainly include: Cherenkov glow detection, total gamma, high resolution gamma spectrum (HRGS), passive neutron and active neutron measurement, etc. The fork-shaped detector composed of passive neutron measurement and high-resolution HPGe gamma spectrometer can be used for burnup measurement of spent fuel, but usually requires a complex hardware system, and the collimation part of the front end of the HPGe detector often needs to be installed Inside the facility, if the system design is not done well in advance, it will be very difficult to retrofit later. [0003] Although the energy resolution of cadmium zinc telluride detectors (her...

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Problems solved by technology

Due to the setting of the track for the CZT detector to move back and forth, the length of the entire measuring device is relatively long, and it is not suitable for random installation and measurement in the storage pool of densely packed spent fuel assemblies.

In addition, in the United States in 2005 patent US6895065-B1, "Gamma spectrometric characterization of short cooling time nuclear spent fuels using hemispheric CdZnTe detectors" (Nuclear Instruments and Methods in Physics Research A 448 (2000) 598-603), "Spent-fuel with character small CZT detectors" (Nuclear Instruments and Methods in Physics Research A 564 (2006) 290-294), French A.Lebrun and Italian R.Berndt have disclosed the use of CZT detectors to measure 134 Cs with 137 Counting rate of Cs to calculate related technologies for spent fuel burnup in spent fuel pools, but there is no automatic control of mechanical parts to achieve optimal measurement conditions

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