Radioactivity decontamination in and around school facilities in Fukushima

摘要

Approximately two months after the Fukushima nuclear accident, the Japan Atomic Energy Agency (JAEA) led off a series of demonstration tests to develop effective but easily applicable decontamination methods for various school facilities in Fukushima. This effort included (1) dose reduction measures in schoolyards, (2) purification of swimming pool water, and (3) removal of surface contamination from playground equipment. Through these demonstration tests, they established practical methods suitable for each situation: (1) In schoolyards, dose rates were drastically reduced by removing topsoil, which was then placed in 1-m-deep trenches at a corner of the schoolyard. (2) For the purification of pool water, the flocculation coagulation treatment was found to be effective for collecting radiocesium dissolved in the water. (3) Demonstration tests for playground equipment, such as horizontal bars and a sandbox wood frame indicated that the decontamination effectiveness considerably varied depending on the material, paint or coating condition of each equipment piece. These findings were summarized in reports, some of which were compiled in localational guidelines or handbooks for decontaminating the living environment in Fukushima.