Method for obtaining radioactive methyliodide vapors under dynamic conditions
- PDF / 594,169 Bytes
- 6 Pages / 595.276 x 790.866 pts Page_size
- 74 Downloads / 218 Views
Method for obtaining radioactive methyliodide vapors under dynamic conditions Alexander V. Obruchikov1 · Aleksei O. Merkushkin1 · Eldar P. Magomedbekov1 · Olga M. Anurova2 Received: 30 July 2020 / Accepted: 26 September 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract A “reagent” preparation technique for producing radioactive methyl iodide vapors applying an isotope exchange reaction has been developed. A laboratory facility for conducting heterophase iodine isotopic exchange under dynamic conditions has been created. Comparative studies of various inert carriers used in chromatography have been carried out. The dependences of the isotopic exchange efficiency on the gas flow rate and the methyliodide concentration are established. Keywords Radioactive methyliodide · Isotopic exchange · Iodine-131 · Iodine adsorbers tests · Gaseous radioactive waste
Introduction The air of nuclear power plants premises, removed by exhaust ventilation systems, can be contaminated with radioactive aerosols and gases. In addition to aerosols, the main danger for personnel and the population is represented by gaseous radioactive isotopes of iodine [1, 2], that get into production areas with uncontrolled leaks in the primary coolant. The ventilation systems efficiency depends directly on the sorbents quality used in gas cleaning devices. To assess the iodine sorbents quality, a unified approach based on the standard test procedure for granular charcoal under laboratory conditions has been developed in Russia [3, 4]. However, sometimes it is necessary to conduct “insitu” tests of iodine filters installed at nuclear power plants in order to confirm the possibility of their further operation or the need to replace sorbents that have reduced or lost their sorption capacity. Firstly, it is associated with temperature and humidity effect on the iodine sorbent, its aging and poisoning during the operation [5–9]. A pulsed supply of gaseous methyliodide ( CH3I) labeled with the isotope I-131 is used as a test agent for such experiments [10, 11]. CH3I is present in the gaseous radioactive waste of nuclear power
plants and is the most difficult to trap chemical form of radioiodine [1, 2, 12]. Radioactive methyliodide is often obtained by the reaction of dimethyl sulfate and metal iodide labeled I-131 [13, 14]. Another option is a contact of liquid methyliodide with Na131I aqueous solution without a carrier [4, 15]. The liquid radioactive methyliodide application is associated with the spillage risk and the indoor air contamination with its vapors during testing or due to safety violations while handling this substance. In our opinion, the optimal approach to obtaining gaseous CH3131I is based on the isotopic exchange reaction under the dynamic conditions. The reaction should take place in a twophase system between pairs of stable methyliodide and metal iodide containing iodine-131. This process can be safely carried out in a small portable radioactive methyliodide generator during acceptance tests and periodic efficiency monitorin
Data Loading...
