ICP-MS based on-line monitoring of Pu-239 airborne concentration.

An online monitoring technology of Pu-239 aerosol based on aerosol direct introduction device, membrane desolvation nebuliser and ICP-MS was established for workplaces of reprocessing plants. Briefly, 0.8 l min-1 Pu-239 aerosol from the workplace was introduced into the aerosol direct introduction device where the air was replaced by Argon, and then the aerosol was introduced into the ICP-MS for measurement. To determine the activity of Pu-239 aerosol, 1.10E-3 Bq ml-1 Pu-242 standard solution generated by a membrane desolvation nebuliser was used. The introduction efficiency of the nebuliser was determined by sampling the aerosol generated from the nebuliser with Lead Standard Solution by glass fiber filter, which was (26.82 ± 3.33) %. The mass bias between Pu-239 and Pu-242 for the ICP-MS measurement was determined by Pu-239 and Pu-242 standard solutions generated by the nebuliser, and mass discrimination correction factor for Pu-239/Pu-242 was 0.972 ± 0.010. The limit of detection (LOD) and limit of quantification (LOQ) of this system were calculated according to the ISO 20 899:2018, which were 2.24E-05 Bq m-3 and 7.45E-05 Bq m-3 with 1 min measurement. The main interference which was from U-238 was determined by U-238 standard solution generated by the nebuliser, and the interferences of U-238 to 239 was (8.50 ± 1.05) E-05. According to the counts of U-238 from several workplaces of reprocessing plant where this system was tested, 239 counts rate from the interferences of U-238 of those workplaces were at the same level of the system background counts, which meant that the LOD above was suitable for those places.

Stack releases of radionuclides from an integrated steel plant in China.

Crude steel production in China made up the majority of the global output, at 49.5% in 2014. High temperature smelting processes result in the release of natural radionuclides, including radon gas and other air pollutants into the atmosphere. This paper conducts an analysis of the raw materials, end products and flue gas sampled from an integrated steel plant from within China's Jiangxi Province, with annual production of 8.50 Mt of crude steel. Normalized stack emissions factors of radionuclides from steel production were first reported in China. The results showed that sintering was the main process that released natural radionuclides, and the main radionuclides released into the atmosphere were 222Rn (86.4 GBq/Mt), 210Pb (13.4 GBq/Mt), and 210Po (1.71 GBq/Mt). The results provided essential basic data for radiological impact assessment of steel production, as well as that of nuclear energy chain, coal chain and other electricity sources.

[Study on the extraction of polysaccharides from Marasmius androsaceus Mycelium].

OBJECTIVE: To optimize the extraction condition for the polysaccharides from Marasmius androsaceus Mycelium. METHODS: The single factor tests and response surface methodology (RSM) were applied. Overall research was proceeded by rational desingn. Technological condition parameters were determined according to regression analysis by SAS. RESULTS: The optimum condition was as follows: extraction temperature was 78 degrees C , extraction-duration was 1. 5h, water to material ratio was 36: 1. The optimum extracting rate for the polysaccharide was 11. 59%. CONCLUSION: The RSM is for optimum extraction process and it will improve the extraction conditions of polysaccharides.