Examination of decontamination of various materials at houses in difficult-to-return zone

Mori, Airi; Tanabe, Tsutomu; Wada, Takao; Kato, Mitsugu

JAEA-Technology 2017-006, 38 Pages, 2017/03

JAEA-Technology-2017-006.pdf:2.98MB

Large quantities of radioactive materials were released into the environment as a result of the Fukushima Daiichi Nuclear Power Station accident. Residential areas and forest areas near the power station were contaminated with the radioactive materials. Outside of the houses, schools and the other buildings are being decontaminated by national authority and local government. On the other hand, the materials (such as walls, floors, or windows) which constitute the houses are not decontaminated officially. In order to prepare decontamination methods that can be applied easily, we conducted examinations of decontamination for various materials in houses. Fibrous materials, woods, glasses, concretes, plastics, vinyl chloride materials, metals and synthetic leathers were used in our examinations. These materials were collected from houses in difficult-to-return zone, and were contaminated by radioactive materials released by the accident. Dry methods (suction, wiping, adsorption and peelable coating), wet methods (wiping, brushing, polishing and washing) and physical method (peeling of materials) were used for decontamination. As a result of our examinations, materials with low water permeability, such as glasses, concretes, vinyl chloride materials and metals, were able to be decontaminated efficiently (about 90% reduction) by using wet methods. Materials with high water permeability like woods were relatively well decontaminated by peelable coating (about 60%-70% reduction). In addition to the examination described above, the difference of contamination reduction effect between chemical properties of detergents and the effect of rubbing of peelable coating were also examined. Finally, the most effective method was summarized based on these examinations.

Radiation shielding provided by residential houses in Japan in reactor accidents accompanied with atmospheric release

Yamaguchi, Yasuhiro; Minami, Kentaro

JAERI-M 90-234, 34 Pages, 1991/01

JAERI-M-90-234.pdf:0.97MB

no abstracts in English

4th International Symposium on Radiation Protection, Theory and Practice

Amano, Hikaru

Hoken Butsuri, 24, p.372 - 373, 1989/00

no abstracts in English

Analysis of influence of indoor radiation dose rates on existence of neighboring buildings using reflection boundary

Furuta, Takuya; Takahashi, Fumiaki

no journal, , 

Precise radiation dose assessment for residents is desired for radiation protection under contaminated environment due to the accident at Fukushima Daiichi Nuclear Power Station. Evaluation of dose rates inside houses is important for this assessment as well as those outside houses by monitoring because people stays inside houses for a large part of a day. We have studied radiation dose reduction inside buildings standing on isolated flat field as the typical data. However, radiation dose reduction for houses in urban area may be different from that for isolated houses because of influence of neighboring buildings. We therefore simulated a situation of infinitely aligned houses virtually by using reflection walls placed at the boundary of geometry containing a house. The radiation dose rate inside this house was computed by transporting radiations using PHITS. We found that dose rates per unit radiation concentration inside the house was lowered as the distance between houses was reduced because of shielding effect by neighboring houses and reduction of radiation source contributed to the dose rate.

Assessment of doses from the contamination inside house in evacuation area

Mori, Airi; Ishizaki, Azusa; Tanabe, Tsutomu; Wada, Takao; Kato, Mitsugu; Munakata, Masahiro

no journal, , 

no abstracts in English

On the characteristics of air dose rate distribution inside and outside Fukushima wooden houses

Kim, M.; Malins, A.; Machida, Masahiko; Yoshimura, Kazuya; Yoshida, Hiroko*; Saito, Kimiaki

no journal, , 

no abstracts in English