Minimum detectable annual dose calculation for routine individual monitoring programme in case of plutonium and uranium contamination of the workplace.

An example of a numerical method application for minimum detectable annual dose calculation that can be guaranteed by the operating monitoring programmes for plutonium and uranium is presented. The method analyses the frequency distribution for a total number of counts obtained in n measurements performed during n monitoring intervals that are inside the calendar year. Urine sample radiometric measurement technique for plutonium and uranium operating monitoring programmes is investigated, showing dependences of the detection limits on the frequency of measurements, on number of calendar years under observation and on the activity median aerodynamic diameter (AMAD). Only a probability density function (PDF), for the background number of counts, stochastic variability of urine excretion and uncertainty of the intake pattern were taken into account as the main variables influencing the calculated detection limits. But there is no limitation for the proposed method to include the variability of other influencing model parameters in the calculation procedure.