Electrolytic decontaminating method for removing radioactive contaminant from metal surface

A metal surface, electrolyte technology, applied in radioactive purification, nuclear engineering and other directions, can solve the problems of long decontamination time, low metal corrosion rate, high decontamination cost, reduce the generation of secondary waste, and wide operating temperature range , the effect of prolonging the service life

Active Publication Date: 2007-06-27
CHINA INST FOR RADIATION PROTECTION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

With the development and improvement of the nuclear industry, most electrolytes cannot be used for electrolytic decontamination of radioactively contaminated materials due to the following reasons: (1) The formula contains chemical components that are incompatible with the waste liquid receiving and processing system of nuclear facilities (such as S, P, halogen, organic matter, etc.), it is difficult to treat the waste liquid after decontamination; Advantages of decontamination; (3) The temperature requirement for decontamination is too high, and a heating device is required to complicate the decontamination device; (4) The formula often contains high-concentration acid, which requires strict material selection for the decontamination device, and the cost of decontamination is high ; (5) The decontamination waste liquid has no self-purification function, and the life of the electrolyte is not long

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] The α surface contamination of a contaminated sample is 2.07×10 5 cpm, β surface contamination is 1.58×10 4 cpm, gamma pollution metering rate 1.67×10 3 cpm. The decontamination device used can be a general tank-type electrolytic decontamination device or an in-situ electrolytic decontamination device.

[0015] Connect the contaminated sample as the anode to the positive pole of the power supply, and the cathode to the negative pole of the power supply, and fill the gap between the cathode and the anode with the electrolyte solution. The electrolyte formula is HNO with a mass percentage of 5%. 3 , the mass percent is 10% NaNO 3 , and the rest is water. The electrolysis temperature is room temperature, and the current density is 0.6A / cm 2 , after 15 minutes of electrolysis, the measured values ​​of α and β surface contamination of the contaminated sample were close to the background, and the decontamination factors were α: 2.59×10 5 , β: 1.32×10 4 , γ: 213.

Embodiment 2

[0017] The α surface contamination of a contaminated sample is 1.61×10 4 cpm, β surface contamination is 1.54×10 4 cpm, gamma pollution metering rate is 29cpm. The decontamination device can be a general tank-type electrolytic decontamination device, or an in-situ electrolytic decontamination device.

[0018] Connect the contaminated sample as the anode to the positive pole of the power supply, and the cathode to the negative pole of the power supply, and the electrolyte formula is HNO with a mass percentage of 4%. 3 , with a mass percentage of 5% NaNO 3 , and the rest is water. The electrolysis temperature is 20°C, and the current density is 0.3A / cm 2 , After 20 minutes of electrolysis, the measured values ​​of α and β surface pollution and the measurement rate of γ pollution of contaminated samples are all background values.

Embodiment 3

[0020] The α surface contamination of a contaminated sample is 2.86×10 5 cpm, β surface contamination is 1.11×10 4 cpm, gamma pollution metering rate is 413cpm. The decontamination device used can be a general tank-type electrolytic decontamination device or an in-situ electrolytic decontamination device.

[0021] Connect the contaminated sample as the anode to the positive pole of the power supply, and the cathode to the negative pole of the power supply. The electrolyte formula is 4% HNO by mass 3 , the mass percent is 10% NaNO 3 , the rest is water, the electrolyte is filled between the cathode and the anode, the electrolysis temperature is 30°C, and the current density is 0.6A / cm 2 , after 20 minutes of electrolysis, the α surface pollution measurement value of the contaminated sample is close to the background, the gamma pollution measurement rate is the background value, and the decontamination factors are α: 1.22×10 4 , β: 455.

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Abstract

The electrolytic decontaminating method for eliminating radioactive contaminant from metal surface includes connecting the decontaminated part to the anode of the power source, connecting decontaminating part to the cathode and feeding electrolyte into the electrolytic decontaminator for electrolytic decontaminating. The electrolyte consists of HNO3 in 3-10 wt%, NaNO3 in 5-20 wt% and water for the rest. The electrolytic current density is 0.1- 0.6A/cm2, and the electrolytic temperature is 20-50 deg.c. The electrolytic decontaminating method may be used for eliminating radioactive contaminant from metal parts of exservice nuclear installation, so that the metal waste may be degraded and reused.

Description

technical field [0001] The invention relates to a method for decontaminating the surface of radioactively contaminated materials, in particular to an electrolytic decontamination method for removing radioactive contamination on metal surfaces. Background technique [0002] The electrolytic decontamination technology abroad was widely used in radioactive decontamination in the early days. In the process of electrolytic decontamination, an efficient electrolyte that can be accepted by nuclear facilities has important practical significance for the application of electrolytic decontamination technology to nuclear facility decontamination. With the development and improvement of the nuclear industry, most electrolytes cannot be used for electrolytic decontamination of radioactively contaminated materials due to the following reasons: (1) The formula contains chemical components that are incompatible with the waste liquid receiving and processing system of nuclear facilities (su...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C25F1/00G21F9/00
Inventor 董毅漫刘文仓任宪文
Owner CHINA INST FOR RADIATION PROTECTION
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