Practical Method for Estimation of Atmospheric Dispersion of Gaseous Material and External Exposure Due to Radioactive Cloud

[摘要] When radioactive gas is discharged into the free air at the time of accident or ordinary operation of atomic plants, discharged effluent is dispersed by atmospheric turbulent diffusion. The concentrations of radioactive airborne substances are governed partly by the source characteristics (height of source, temperature and velocity of emission of the discharged gases) and partly by meteorological parameters. Many studies for dispersion formula have been presented by O. G. Sutton (1947), F. Pasquill (1958), P. J. Meade (1958, 1960), J. Sakagami (1960) and others.In this paper, first a brief description is given of PbI2 smoke experiments that have been tried within a few kilometers range at Tokai-Mura (Ibaraki Pref., Japan) from 1958 to 1959. The results of experiments show a good agreement with those of computations which are obtained by Meade's method (1958). Next, the author describes of 41A gas release experiments (1961) in use of JRR-2 at JAERI, in which we measured of ray total external ex-posure on the ground surface during 41A cloud passage by a network extended 2 km downwind.As a result, we have certified that measured exposure shows a good agreement with ones which are calculated under the assumption of spatial concentration distributions obtained by Meade's method (1958).

[学科分类] 大气科学