Model-based analyses of the cesium dynamics in the small mesotrophic reservoir, Pond 4. I. Estimating the inventories of and the fluxes among the pond's major biotic components.

A model of cesium (Cs) dynamics among the principal biotic and abiotic components of an 11.4-ha impoundment is described. The model is derived from analyses of field measurements of Cs-133 concentrations in pond components for 500 days following the addition of 4 kg of stable Cs-133 to the system.

Effect of the duration time of a nuclear accident on radiological health consequences.

This study aimed to quantify the effect of duration time of a nuclear accident on the radiation dose of a densely populated area and the resulting acute health effects. In the case of nuclear accidents, the total emissions of radioactive materials can be classified into several categories. Therefore, the release information is very important for the assessment of risk to the public.

Radiological risk assessment caused by RDD terrorism in an urban area.

This paper specifically discusses a radiological risk assessment due to RDDs (Radiological Dispersion Devices) containing Cs-137 in the metropolitan area of Seoul, South Korea. The comparison of an effective dose caused by airborne plume and deposited Cs-137 is performed with and without consideration of the wind direction. When the dose is computed conservatively, an effective dose is around twice that of a dose computed realistically.

Analysis of atmospheric dispersion factors for building wakes at the Wolsung nuclear site in Korea.

The characteristics of atmospheric dispersion considering the building effects in the Wolsung nuclear site in Korea were studied using ISC-PRIME and ARCON96 models. The maximum 2-h average atmospheric dispersion factor (ADF) was six times larger when the building geometry was considered in ISC-PRIME and two times larger in the exclusion area boundary. Owing to different adjustments for wind speed by the stability class, the ADFs calculated using ARCON96 were smaller than those calculated using ISC-PRIME.

Development of a radioactivity mapping tool to support the decision making for radiological emergency events.

A radioactivity mapping program was developed to support the decision making in case of a radiological emergency event. Geostatistics and kriging methods were used in the program to make a more accurate radioactivity map for the polluted area. Two variogram models, i.

Statistical approaches to forecast gamma dose rates by using measurements from the atmosphere.

In this paper, the results obtained by inter-comparing several statistical techniques for estimating gamma dose rates, such as an exponential moving average model, a seasonal exponential smoothing model and an artificial neural networks model, are reported. Seven years of gamma dose rates data measured in Daejeon City, Korea, were divided into two parts to develop the models and validate the effectiveness of the generated predictions by the techniques mentioned above. Artificial neural networks model shows the best forecasting capability among the three statistical models.

Determination of the source rate released into the environment from a nuclear power plant.

A study was carried out to determine the source rate from a nuclear power plant using the tracer experimental data conducted at the Yeoung-Kwang nuclear site. The least squares method optimises the agreement between the released source rate and the calculated source rate by minimising the errors between the measured concentrations and the calculated ones using the Gaussian plume model. The least squares estimator generally estimates the source rate to be within a factor of 2.