Nuclear power plants and their environmental impact

Methods are considered which are used in the estimation of the amount of radioactivity in the environment of a nuclear power plant caused by a gaseous discharge. It is outlined globally how data are used and which assumptions are made. Much attention is devoted to the gaussian plume model, a description of the spread of smoke gases into the atmosphere. According to this model the concentration is a function of the distance with respect to the source, the chimney and some parameters, like the velocity of the gas cloud and the standard deviations in the direction perpendicular to the movement of the gas cloud. For the values of these parameters various results from literature are compared and an estimation has been made. For the relative error in the concentration this holds to be equal to the sum of the relative errors in the aforementioned parameters. Apart from the description of waste currents, the dose-response relations for low ionizing radiation doses and a discussion about the source term, a crude estimation has been made of the dose for an individual at a distance of about 10 km of a normal nuclear power plant in operation in the Netherlands. Therewith it is assumed that his food predominantly originates from the surroundings. This estimation yields a value of 50±25 mREM a year when the power plant discharges the maximum allowed quantity of radioactive waste. Following various publications nuclear power plants discharge only a few percent of the allowed quantity. 15 refs.; 13 figs.; 27 schemes; 21 tabs