A Numerical simulation of I in the atmosphere emitted from nuclear fuel reprocessing plants

Nishizawa, Masato; Suzuki, Takashi  ; Nagai, Haruyasu  ; Togawa, Orihiko 

Suzuki et al. (, , 268-275, 2008) estimated that more than 80% of Iodine-129 (I) in seawater in the Japan Sea came from nuclear fuel reprocessing plants. Considering the distance from the main nuclear reprocessing plants in Europe to the Japan Sea and the time scales of atmospheric and ocean circulations, large portion of I in the Japan Sea is presumed to be transported through the atmosphere. In the present study, a global chemical transport model, MOZART-4, is applied to investigate the behavior of I emitted from nuclear fuel reprocessing plants in Europe (Sellafield in the UK and La Hague in France) and to estimate the distribution in the atmosphere and deposition in remote sites. The result of numerical simulation for more than fifty-year period from the 1950s is validated by comparison with measurements of I around the world and analyzed to clarify the characteristic of the distributions of concentration and deposition of I. The modeled concentrations of I in precipitation in Europe and depositions in Japanese waters are in the same order as measurements. The emitted I to the atmosphere is distributed and deposited all over the Northern Hemisphere due to the prevailing westerlies. The emission of I to the atmosphere is thus important in considering the transport and deposition of I to remote sites.