Influence of conversion factors on the radioactivity evaluation of clearance objects consisting of several materials.

Control panel waste generated from nuclear power plants is a new candidate for clearance under Japan's amended regulations. In the radioactivity evaluation, a simplified conversion factor for density and source location conditions has been used, assuming that it applies to unmixed materials such as metals. To investigate its applicability to control panels consisting of metal and organic materials, we examined the application of the conventional conversion factor by simulations of radiation measurements for a point source in a control panel.

Evaluation of the probability distribution of radioactivity estimated by inverse problem solution using Monte Carlo Method.

In this study, we derived the posterior probability distribution of the total activity estimated by inverse problem solution. The posterior probability distribution was derived by applying the Monte Carlo approach of the GUM Supplement 1 to the model of evaluation. The decision threshold, the detection limit, and the limits of the coverage interval for the results, all of which are defined in ISO 11929-2 as characteristic limits, were also derived.

Derivation of uncertainty propagation for clearance measurement.

Clearance measurements are performed to calculate the sum of the ratios of the measured activity concentration to the limit for all nuclides to be considered. In the derivation of the uncertainty, the modeling of the measurement is essential. By using formula for the modeling, the uncertainty and upper limits of the coverage interval can be calculated by uncertainty propagation.

Evaluation of the detection limit of net count in peak for the energy spectrum of CZT detector.

Pulse shape processing techniques have been used to improve the energy spectrum of the cadmium zinc telluride (CZT) detector, however, quantitative evaluation of the improvement, to determine whether it is acceptable to the related stakeholders, is required. In this study, the detection limit of net count in the full-energy absorption peak according to ISO 11929-1:2019 was selected to quantitatively evaluate the improvement of the characteristics of net count in the peak in the energy spectrum.

Reduction of left-lateral segment from living donors for liver transplantation in infants weighing less than 7 kg: technical aspects and outcome.

LLS reduction has been frequently used in infants weighing <7 kg. Twenty recipients weighing <7 kg at the time of LDLT, median age 11.0 months and body weight 5.