Kr-85 sealed radioactive source vacuum inflation system and inflation method

Abstract

The invention relates to a Kr-85 sealed radioactive source vacuum inflation system and an inflation method. The system comprises a booster pump, an aluminum protection module, a radioactive source tank, a low-temperature recovery tank, a reserved expansion port, an instrument, a valve assembly, a pneumatic control component, a pneumatic pump, a vacuum pump and a control box, wherein the pneumaticpump, the vacuum pump and the control box are used in matching. The inflation method comprises the following steps of source box installation; system vacuumizing; source box leakage detection; raw material gas releasing; inflating or pressurizing and inflating; source shell connection cutting off and source shell sealing; liquid nitrogen adding, and pipeline gas recovering by a raw material tank;and liquid nitrogen adding, and residual gas recovery by a tail gas tank. By means of the system, the operation safety is improved, the Kr-85 sealed source performance is improved, the production process is simplified, the inflation pressure is increased, emergency treatment is conducted on accidents in the radioactive source production process, safety protection measures are set, misoperation isprevented, and meanwhile, efficient recovery of residual radioactive gas is achieved.

Description

technical field [0001] The invention belongs to the field of radioactive source vacuum inflation, and in particular relates to a Kr-85 sealed radioactive source vacuum inflation system and an inflation method. Background technique [0002] The Kr-85 sealed radioactive source is a radioactive source made by sealing Kr-85 gas in the source cladding. Kr-85 sealed radioactive source is generally used in β-ray thickness gauge to measure the thickness of paper and film. [0003] There are two methods for preparing the Kr-85 sealed radioactive source: one is to immobilize Kr in a solid carrier by adsorption to make a solid source. Adsorbents include activated carbon, silica gel, zeolite, and cage-like organic compounds such as quinone and the like. However, since the Kr-85 solid source is not very stable, it is only reliable in low temperature environments. When serving in high temperature environments, Kr will decompose from the solid adsorbate. Another preparation method is us...

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Problems solved by technology

[0005] Because the valves of the system are manual valves, it is easy to cause high doses to the hands; the pipeline volume of the system is large, the vacuum pumping efficiency is low, the production operation time is prolonged, and the exposure dose of personnel is prolonged

Due to the large volume of the pipeline, the 85 The recovery efficiency of the Kr gas cold trap is certain, and there will be residual radioactive gas in the pipeline (the dose on the outer surface of the pipeline can reach 5μSv / h), and the residual gas will be pumped out of the system during the subsequent vacuum pumping, which will easily cause excessive emissions.

The source shell interface is a vacuum rubber tube, which is more prone to aging in the radiation field, causing leakage at the connection, and leaks are prone to occur during the vacuuming and inflation of the source shell

The early Kr-85 sealed radioactive sources were all negative pressure sources. This system has disadvantages such as poor inflation pressure accuracy and poor safety.

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