As the decommissioning of nuclear power plants progresses, interest in the inevitably generated radioactive waste is also increasing. Especially, because the containers of ILW packages are significantly more expensive than the containers of LLW packages, the special attention should be focused on minimizing the number of the containers of ILW packages. The radiation dose limit for packaging of ILW shall not exceed 2 mSv/h and 0.1 mSv/h on contact and at 2 m, respectively in South Korea. Meanwhile, The DEMplus provides various environmental geometry and all properties such as materials, absorptions, and reflections and the estimation of the radiation dose rates is based on the radiation interactions of the designed 3D geometry model. With the consideration of the radiation dose rate by using DEMplus and its strategy of packaging and cutting plan, the number of containers for ILW packages generated from decommissioning of Reactor Vessel Internal (RVI) of a nuclear power plant that has been in operation for decades was optimized in this paper. The modular shielded containers (MSC) with shielding inserted were used for radioactive wastes that require shielded packaging. In order to verify the accuracy of the estimated radiation dose rate by using DEMplus, the estimated results were compared with those obtained using MicroShield. The trends of the estimated radiation dose rates using DEMplus and the estimation of MicroShield were similar to each other. The results of this study demonstrated the feasibility of using DEMplus as a means of estimating the radiation dose limit in packaging plan of the radioactive waste.

As the decommissioning of nuclear power plants increases, there is an increasing interest in the amounts of radioactive waste. Especially, the radiation dose limit for packaging of radioactive wastes shall not exceed 2 mSv·h−1 and 0.1 mSv·h−1 on contact and at 2 m, respectively in South Korea. The DEMplus provides various environmental geometry and all properties such as materials, absorptions, and reflections and the estimation of the radiation dose rates is based on the radiation interactions of the designed 3D geometry model. With the consideration of the radiation dose rate by using DEMplus and its strategy of packaging plan, the radiation shielding was optimized and estimated in this paper. The modular shielded containers (MSC) with shielding inserted were used for radioactive wastes that require shielded packaging. In order to verify the accuracy of the estimated radiation dose rate by using DEMplus, the estimated results were compared with those obtained using MicroShield. The trends of the estimated radiation dose rates using DEMplus and the estimation of MicroShield were similar to each other. The results of this study demonstrated the feasibility of using DEMplus as a means of estimating the radiation dose limit in packaging plan of the radioactive waste.

In the dismantling process of a reactor coolant system (RCS) piping, a radiation protection plan should be established to minimize the radiation exposure doses of dismantling workers. Hence, it is necessary to estimate the individual effective dose in the RCS piping dismantling process when decommissioning a nuclear power plant. In this study, the radiation exposure doses of the dismantling workers at different positions was estimated using the MicroShield dose assessment program based on the NUREG/CR-1595 report. The individual effective dose, which is the sum of the effective dose to each tissue considering the working time, was used to estimate the radiation exposure dose. The estimations of the simulation results for all RCS piping dismantling tasks satisfied the dose limits prescribed by the ICRP-60 report. In dismantling the RCS piping of the Kori-1 or Wolsong-1 units in South Korea, the estimation and reduction method for the radiation exposure dose, and the simulated results of this study can be used to implement the radiation safety for optimal dismantling by providing information on the radiation exposure doses of the dismantling workers.

The healing environment in hospitals is very important. Three factors must be satisfied to create a healing environment in the hospital. First, chemical elements such as pathogens and pollutants must be controlled. Second, physical factors such as temperature, humidity and airflow must be satisfied. Third, psychological factors must be satisfied. The purpose of this study was to evaluate the indoor thermal environment by conducting a questionnaire (Thermal Sensation Vote, TSV) and a Predicted Mean Vote (PMV) measurement. The questionnaires were distributed to 20 medical staff (nurse), 84 inpatients and 113 outpatients. Temperature, humidity, air quality and comfort were evaluated. Measurements were conducted in the waiting room and lobby of the first and second floors of the outpatient area as well as wards on 10th floor. Both south and north-facing wards were divided to analyze the PMV difference by the orientations. The survey results showed high satisfaction values in the outpatient department for temperature satisfaction and comfort. In the inpatient department, air quality satisfaction showed good values. Moreover, the humidity satisfaction level in the nurse station was high. The PMV measurement results showed that the PMV was lower in the ward than in the outpatient area. Comparison of the questionnaire and measurement results showed that the questionnaire results were lower than those of the measurement in the outpatient area. As a result, it is necessary to reduce the gap between questionnaire and measurement results It is also important to create an indoor environment that matches the thermal preferences of the occupant by operating the air handling unit (AHU).

It is known that air pollutants such as fine dust and exhaust gas from vehicles are harmful to human health. In particular, the black carbon emitted by vehicles is known to cause a large number of premature deaths. This study analyzed the effect of a noise barrier on the inflow amount of black carbon from a nearby high traffic road to a school area, using numerical analysis performed at two elementary schools. Also, the correlation between the noise barrier’s shape, height and the inflow amount of black carbon was assessed. As a result, it was found that the higher the noise barrier, the lower the inflow amount of black carbon observed at the school A. However, the inflow amount of black carbon at school B was not greatly influenced by the height of the noise barrier. The inflow amount of black carbon at the schools could be changed not only by the height of the noise barrier, but also by the shape, height and position of the noise barrier and the school building.

The concern of fine particle (PM2.5) management of outdoor environments has been increasing due to its exposure and related health effects in Korea. As a result, PM2.5 standard in atmosphere environment was regulated in 2015. On the other hand, indoor PM2.5 standard has been required because most people spent their times in indoor environments. In this study, we measured the PM2.5 and PM10 concentrations both indoor and outdoor environments of public-use facilities such as underground stations, underground shopping centers, and nurseries for 24 hour with filter-weighing method in Seoul and Daegu. Measurement duration was from March to April in 2014 during the Asian dust period. At all measurements, indoor to outdoor (I/O) concentration ratios exceeded 1 except 1 day nursery in Daegu in spite of Asian dust period. The ratios of PM2.5 to PM10 concentrations ranged from 0.63 to 0.75 in indoor environments, and from 0.63 to 0.82 in outdoor, indicating that PM2.5 should be carefully managed in indoor environments as well as outdoor atmosphere.