CALCULATION OF CONTROL AND ACCEPTABLE LEVELS OF RADIATION FACTORS FOR NUCLEAR PROPULSIONS

In accordance with requirements of regulatory and guideline documents on radiation safety for controlled radiation factors for the purposes of operating control, controlled and acceptable levels are established. Any excess of these levels requires the determination of the causes and implementation of actions designed to eliminate the excess. The paper presents the method of calculation of these levels and establishing the levels in practice at the present time, disadvantages of accepted regulations are analyzed. It was shown that existing documents do not take into account some circumstances that define the radiation safety test procedure. In a number of measured control points of the radiological situation and staff radiation exposure, the values of controlled parameters are independent of reactor system mode. In the same points that show the dependence of measured data on a reactor power level, values of controlled parameters may also depend on a mode of pumps and purification system. Furthermore, real-time measurements review has showed that beyond the range of lower limit of measuring range of verification means in the range with nonspecified error, the measured data variance is described by mean value and acceptable error. At the same time, a mean value may be a lower order to lower limit of measuring range. Setting a value of controlled level equal to a sum of a mean of double or tripled root-mean-square deviation depending on the accepted confidence level, a possibility of earlier detection of controlled level excess emerges. In this situation, an exact absolute value of a controlling parameter is not essential as that radiation factor level poses no hazard to life. It is important to capture the onset of significant increase of radiation factor i.e. change of radiological situation.

marine medicine, acceptable level, controlled level, radiological safety, radiation control, effective dose