On minimization of potential harm to health from the planned special exposure of the personnel of radiation hazardous facilities

The method that substantiates the management decisions to minimize potential harm to health of employees at radiation hazardous facilities associated with the planned special exposure is presented in the article. The simple way to reduce collective radiation-associated risk for the employees is to distribute those admitted to the planned special exposure in accordance with the value of their expected individual risk. This approach will allow selecting the workers with the least expected risk. The risk was calculated with the use of computer program "PPO" based on ICRP mathematical models recommended for assessment of radiation risks. Risk values were estimated for employees at 105 radiation hazardous facilities affiliated to the State Corporation “Rosatom”. Potential health risks related to the planned special exposure were calculated for every employee, who could receive integrated dose of 200 mSv including radiation doses received previously. The basic parameter of the individual risk is the ratio of expected risk, associated with the planned special exposure, to expected individual health risk, associated with exposure to background radiation for subsequent 30 years, it is expressed as the number of lost days of life. For estimation of the maximum individual dose to be received by an employee as a result of the elevated exposure the following requirement should be met: the worker's risks ratio should not exceed the estimated limit determined from analysis of expected risks. When planning the special exposure to a dose of 200 mSv, the highest ratio of individual risks should not exceed 33%, and the averaged employees’ risk ratio should be 8%. Maximum radiation dose, that could be received by 450 employees as a result of the planned special exposure was calculated. The doses meeting the above requirement vary between 100 mSv and 200 mSv. It is recommended to use this dose range when planning special exposure.