Effects of Time Passage and Distance on Distribution of Carbon-14 among Parts of Rice during Growth Period at Korean CANDU Plant

The pattern of carbon-14 (C-14) distribution among parts of rice growing in the vicinity of the Korean CANDU plant during the growth period was investigated. Six-time samplings of rice and air were performed in seven fields from rice planting to harvest, and the measurements of C-14 content were made by using liquid scintillation counter on the air and each of available parts of the rice such as root, stem, crust and ear. The results illustrated that C-14 showed a relatively even distribution among parts of rice during the growth period implying C-14 accumulation was more dependent on interactions among the parts such as transportation of nutrients than on photosynthesis occurring only in stem that has chlorophyll. Also it was observed that the difference of C-14 concentration between each part of rice and the air decreased with time indicating that the time was needed for C-14 to reach equilibrium between both sides. The radius within which C-14 released from the Wolsong plant could have a significant effect on the C-14 concentrations of the parts was observed to be about 5 km.