Abstract
This study extended the capabilities of PCTRAN by including the Gaussian puff model and the basic numerical techniques, to efficiently calculate the radioactive effluent dispersion. PCTRAN is a PC based nuclear power plant simulation code, and capable of running faster than real time. Accident initiation events can be activated in the simulation software, and the radioactive materials are assumed to be released from the plant to the atmosphere at every time of interval. During a transient or an accident simulation, puffs are sequentially generated and dispersed in all directions governed by the Pasquill stability category, wind velocity and wind direction. The thyroid dose rate and whole body dose rate (as well as their accumulations) at every spatial location in the emergency planning zone (EPZ) are shown as a color-shaded plot. A postulated scenario was given in PCTRAN to demonstrate that the code predict the time-varying distributions of thyroid and whole body dose rates (and their accumulated dosages) efficiently. Therefore, the urgent decision-making on protective actions can be determined ahead of the accident time.
