放射能汚染土壌洗浄処理における高濃縮汚染残土固形化処理性能評価

Performance evaluation of a solidification process for highly concentrated radiation contaminated surplus soil

石山 新太郎; 大谷 和久*; 山下 学*

Ishiyama, Shintaro; Otani, Kazuhisa*; Yamashita, Manabu*

570,000Bq/kgを越える福島県下の放射能汚染土壌の洗浄プロセスにおいて固形化工程に使用する可搬型(360mmD360mmH800W)と固定大型フィルタープレス(1880D2140H9085W)の性能評価を行うため、汚染土壌の洗浄試験とそれに基づく放射線量評価を実施し、下記結論を得た。(1)可搬型フィルタプレスにより10%近い減容率を達成するとともに、濃縮固形化に伴う放射線量は出発土壌の1.3-6.7倍に達した。(2)高縮固形化工程における可搬型及び大型固定型フィルタプレス装置の中心における線量はそれぞれ2.5及び196Sv/hであり、特に大型固定型においては通常及び異常時点検補修の際に放射線防護規定の放射線量を越える危険性がある。

For the purpose of performance evaluation of the field portable (360 mmD 360 mmH 800 mmW) and fixed mount type filter presses(1880 mmD 2140 mmH 9085 mmW) for soil consolidation in radiation contaminated soil washing process, decontamination water washing test and radiation assessment for these filter presses were conducted with over 570,000 Bq/kg radiation contamination soil in FUKUSHIMA and the following results were derived; (1) About 10% volume reduction was achieved in soil consolidation process by the field portable filter press with 1.3-6.7 times high condensation of radiation density. (2) During soil consolidation, core dose in the field portable and fixed mount type were evaluated as 2.5 and 196 Sv/h, respectively, and exposed dose in ordinary maintenance and inspection in excess of radiation protection guide level, especially for the fixed mount type in terms of radiation protection.