Operation and reliability characteristics of radiation loop

Abstract

The radiation loop (RL-L) was first constructed at the research nuclear reactor of the Institute of Physics, Latvian SSR Academy of Sciences, in 1963, the total activity of gamma radiation source being 25 kCi (1). The radiation loop was reconstructed simultaneously with the reactor, and in 1976 its activity was 80 kCi (2). In the loop, the alloy circulates from the activity generator located in the reflector of the reactor, to the irradiators which are placed in the working chamber. Liquid metal In-Ga-Sn alloy serves as gamma carrier. Two types of irradiators are installed in the radiation loop. The irradiators of various designs might be installed and used for carrying out specific chemical, physical and biological radiation processes. A working chamber of an appropriate space is available for the irradiation of samples (2). An original hydraulic circuit with a single circulation of gamma-carrier within the activity generator and irradiators have been used in the radiation loop RL-LM (3, 4). The circuit contains no mechanical valves. A number of radiation-proof MHD devices, such as electromagnetic pumps, flowmeters, a level gauge and others have been developed and tested in order to provide maintenance. The main contribution (96%) from the total gamma radiation power is due to gamma radiation from the short half-life (54.12 min) isotope In 116m. The total activity of gamma-carrier is 80 kCi, whereas the total gamma radiation power is 1.22 kW and mean gamma quantum energy is 1.15 MeV. The maximum dose rate is 21 Mrad h .