Assessment of Radiological Dose around a 3-MW TRIGA Mark-II Research Reactor

Abstract

A hypothetical accidental case of a 3-MW TRIGA Mark-II research reactor has been assumed to assess the radiological consequences due to the deposition of 137 Cs and 90 Sr on ground, vegetation, milk and meat. The air concentrations in sixteen cardinal directions have been estimated where the maximum concentration has been found to be at 110 m distance from the core of the reactor for all the directions. Calculated maximum doses of 137 Cs, 90 Sr and both 137 Cs and 90 Sr have been found to be within the ranges of 0.005-0.014 μSv hr –1 , 0.013-0.036 μSv hr –1 and 0.018-0.05 μSv hr –1 , respectively for all the directions, which are below the measured background dose limit 0.25 μSv hr –1 and also within the IAEA acceptable dose rate limit of 0.5 μSv hr –1 . The calculated low doses due to the aforementioned radionuclides can be considered negligible with regard to the radiation hazards. The relationship between total effective dose rate for various pathways (i.e. immersion, inhalation, ground deposition, and ingestion of contaminated vegetation, milk, meat) and air concentration in all the directions has been established. Obtained relation reveals that the total effective dose rate is directly proportional to the air concentration, and the overall proportionality constants for 137 Cs and 90 Sr radionuclides have been obtained as 0.57 and 0.28, respectively. This study might provide information on the radiological safety required for the radiation protection purposes of the people living in the vicinity of the reactor site.