Radiological assessment of the decontaminated and decommissioned Korea Research Reactor-1 building

Establishment of analysis methodology for ionizing mattresses using RESRAD-BUILD code

The methodology of analysing ionizing mattresses using the RESRAD-BUILD code is described. RESRAD-BUILD is a free computer program developed by Argonne US National laboratory. The RESRAD-BUILD code can analyze radiation exposures resulting from occupying a building contaminated with radioactive materials or housing contaminated furniture or equipment. In May 2018, the South Korean government pulled the mattresses of manufacturer Daijin Bed Co from its markets because these mattresses had unsafe radiation levels. After that, the AEC (Atomic Energy Council, Taiwan) had immediately conducted an inspection of ionizing mattresses of Taiwan and found that the radiation level of mattresses of two domestic brands exceed the legal standards. For assessing the dose of the ionizing mattress, it was necessary to establish a methodology for analyzing these in case of nuclear industry unusual products. This was done by using the RESRAD-BUILD code and the data are presented in this manuscript. The analysis results of RESRAD-BUILD were compared with the assessment result to the dose announced by the AEC. The RESRAD-BUILD result which the air exchange rate is 10–2/h is similar with the AEC data. In addition, the results present that the air exchange rate is very significant for calculating the dose.

Comparative Analysis of Probabilistic Analysis and Deterministic Analysis by RESRAD Code

The decommissioning of nuclear facilities indicates that the site is finally released according to a limited or unlimited site reuse purpose. In this process, the assessment of exposure dose to decommissioning workers and nearby residents is essential. Based on MARSSIM, a widely used decommissioning guideline in the United States, derivation of the exposure dose and derived concentration guideline level (DCGL) is mandatory using the probabilistic analysis of the RESRAD code. Here, DCGL is the radionuclide-specific concentration that satisfies the site release criteria. By applying the priority 1 parameter, which has the greatest effect on the dose, the dose is derived through deterministic and probabilistic analyses. The results were compared and analyzed. The purpose of this study was to provide a basic database that can be applied to the development of parameter lists and distributions suitable for the characteristics of nuclear facilities in South Korea. In addition, the process of deriving the dose by applying the deterministic and probabilistic analyses of RESRAD was assessed.