Theoretical basis for reduction of number of survey units of MARSSIM final status survey at decommissioning facilities

To investigate the effects of combining two survey units quantitatively in the final status survey of MARSSIM for a decommissioning facility, an expression for the sample size of combined survey unit was developed, which consists exclusively of related parameters of the two survey units. The simulation results using the expression showed that all combining cases considered always result in a decrease in the overall sample size and that it is beneficial to combine two survey units whose radiological characteristics are similar or not significantly different from each other to obtain more decrease in the overall sample size. The results also show that it is necessary to check the practicability of a specific combining case since not all the combined survey units have reasonable sample sizes to obtain. The results also implied that dividing a single survey unit into two separate survey units would result in an increase in the overall sample size. (C) 2021 Elsevier Ltd. All rights reserved.