Investigators: Kenzo Nishimaki, Akio Koyama & Satoshi Fukutani
Abstract: Most of the low level radioactive wastes arising from the nuclear reactor decommissioning are concretes and metals. It is important to dispose them safely. Radioactivity of Cs-134, Co- 60, and Eu-152 in the reactor biological shielding concrete of Kyoto University Reactor (KUR) was estimated based on elemental analysis and the calculation of neutron reaction, and these values were compared with the values of clearance levels or legal regulation. Tritium is another key element of the safety evaluation when very low-level radioactive waste is submitted to trench disposal because artificial and natural barriers are not considered effective for tritium migration. 192 concrete samples were irradiated by neutron using Pn-2 facility of KUR and immersed in leaching water to obtain basic data for the creation of tritium in neutron irradiated concrete and its leachability in water.
Publications:
A.Koyama and K.Nishimaki; Environ. Sanit. Eng. Res., 12, 3,
1998 (in Japanese)
A.Koyama and K.Nishimaki; Environ. Sanit. Eng. Res., 13,
3, 1999 (in Japanese)
A.Koyama et al. ; Environ. Sanit. Eng. Res., 14, 3,
2000 (in Japanese)
A.Koyama; Proceedings of the 35th Scientific Meeting of
KURRI, 2001 (in japanese)
Investigators: Satoshi FUKUTANI, Akio KOYAMA & Kenzo NISHIMAKI
Abstract: Many toxic materials, such as heavy metals and radionuclides, are added on the environment. They reach the food chain via ground surface and underground water, resulting in public risk and potential heath hazard. The purpose of this study is to evaluate the reaction of such additional materials with soil constituents and the migration of them in the ground. Antimony(Sb), one of such toxic materials, was proved that when it was added on the ground soil, small amount of antimony was migrated to liquid phase and there ware at least two, fast and slow, migration velocity.
Publications:
S.Fukutani et al.; Environ. Eng.Res. Vol.35, 153-160, 1998
(in Japanese)
S.Fukutani et al.; Water Purification and Liquid Wasters
Treatments, Vol. 41, 257-260, 2000 (in Japanese)
S.Fukutani al.; Environ.
Sanit. Eng. Res., Vol. 12, 198-203, 1998 (in Japanese)
Investigators:Hiroaki KOIDE & Tetsuji IMANAKA
Abstract: For the purpose of evaluating environmental impact of radioactivity release from nuclear facilities, we have been continuing radioactivity monitoring around several facilities. In 1999 the criticality accident that happened in the JCO uranium fuel company was the most severe accident in the Japanese history of the atomic energy development because two operators were exposed by fatal amount of radiation and died. Many employees and residents were also exposed by radiation of more than permission dose. We have investigated the effects of the accident, i.e. neutron doses and radioactive contamination in environment.
Publications:
H. Koide; Radioactive Contamination and Exposure,
Gijutsu-to-Ningen, Vol. 28, December 1999 (in Japanese).
H. Koide; Health
Physics and Nuclear Disaster Prevention, J. Health Physics, Vol. 35 No.1,
36-38(2000) (in Japanese)
H. Koide; Radioactive Contamination from the JCO
Criticality Accident, J. Environ. Radioact 50 (1-2) 123-130(2000)
Investigators: Tetsuji IMANAKA & Hiroaki KOIDE
Abstract: One of important issue in which our society is now involved is whether we depend on nuclear energy or not. In order to find a reasonable answer to this issue it is necessary to clarify merits and demerits accompanying the use of nuclear energy. Our group has been analyzing various aspects of demerits of nuclear energy including radiological consequences of the nuclear accidents such as TMI-2 (USA 1979), Chernobyl-4 (USSR 1986), JCO criticality accident (Japan 1999) etc.
Publications:
A. Adachi, H. Koide; Can we live with Nuclear Power?,
Kamogawa-Publishing Co. Ltd., (1998) (in Japanese).
O. Nasvit, T. Imanaka; J.
Health Physics, Vol. 33 No.2, 1998.
T. Imanaka ed.; Radiological Consequences
of the Chernobyl NPP Accident: International Collaboration Report,
Gijutsu-to-Ningen, 1998 (in Japanese).
T. Imanaka; Gijutsu-to-Ningen, Vol.
28, December 1999 (in Japanese).
T. Imanaka; Gunshuku, Vol. 223, May 1999 (in
Japanese).
T. Imanaka; J. Environ. Radioactivity, Vol. 50 No.1-2, 2000.
K.
Komura, A. Yousef, Y. Murata, T. Mitsugasira, R. Seki, T. Imanaka; J. Environ.
Radioactivity, Vol. 50 No.1-2, 2000.
Investigators: Kenzo Nishimaki & Akio Koyama
Abstract: Organic liquid waste is difficult to treat by conventional radioactive liquid treatment processes, but in order to reduce long-term irradiation of the public the removal of radionuclides from such waste is preferable to dilution. Activated sludge processes are considered appropriate means for treating radioactive organic liquid waste. In this process, the fate of radionuclides eluted by treated water or immobilized by activated sludge, is extremely important for public safety and for the treatment of radioactive organic liquid waste.@We made uptake and desorption behavior experiments on the three short half-life radionuclides and used three nutritive types of artificial sewage as the feed solution. Then we discuss the uptake-desorption behavior of these radionuclides in an activated sludge process.
Publications:
A.Koyama et al.; Environ. Sanit. Eng. Res., 9, 3, 1995(in Japanese)
A.Koyama and K.Nishimaki; Environ. Sanit. Eng. Res., 10, 2, 1996
K.Nishimaki and A.Koyama;J. Environ. Syst. and Eng.,JSCE, No.566/‡Z-3, 1997
A.Koyama and K.Nishimaki; Waste Management, 17, 1 1997
Investigators:Kenzo Nishimaki & Naoya Satta
Abstract:Radionuclides in waste materials were disposed of on land. They reach the food chain via surface and underground water, resulting in public risk and potential heath hazard. The purpose of this study is to evaluate the reaction of radionuclides with soil constituents and the migration of them in the ground. Simple methods were developed to estimate the migration rate of Cs-137 in the undisturbed urban soil. The sorption of radioactive iodine(iodide and iodate evidenced by the breakthrough data, was investigated. Plural and specific sorption mechanisms were considered for iodide. A simple anion exchange reaction is found for iodate.
Publications:
N.Satta et al.;Environ. Sanit. Eng. Res.,9(3),217-222,1995 (in Japanese)
N.Satta et al.;Environ. Sanit. Eng. Res.,10(3),146-151,1996 (in Japanese)
N.Satta et al.;KURRI-KR-1,25-30,1996 (in Japanese)
N.Satta et al.;KURRI-KR-1,31-36,1996 (in Japanese)
N.Satta et al.;Environ. Sanit. Eng. Res.,11(3),195-200,1997 (in Japanese)
Investigators:Hiroaki Koide & Tetsuji Imanaka
Abstract: For the purpose of evaluating environmental impact of radioactivity release from nuclear facilities, we have been continuing radioactivity monitoring around several facilities. In 1988 the existence of high radiation area was disclosed around the Ningyo-toge mine that was closed in 1967. The origin of radiation is mining residues discarded and left as they were since the close of mining. Our group detected high concentration of Rn222 in air at an entrance of the old shaft. Since last year we have been trying to measure Radon daughter nuclides.
Publications:
M. Enomoto & H. Koide; Document: The Ningyo-Toge Mine, Hokuto-Shuppan,
1995(in Japanese)
H. Koide; Asio, Minamata and Ningyou-Toge, Environment and Society, 15,7-16(1997) (in Japanese)
H. Koide; Uranium Mining and Ningyou-Toge Uranium Mine, The News of Citizensf Nuclear Information Center, 281,9-10(1997)(in Japanese)
Investigators: Tetsuji Imanaka & Hiroaki Koide
Abstract: One of important issue in which our society is now involved is whether we depend on nuclear energy or not. In order to find a reasonable answer to this issue it is necessary to clarify merits and demerits accompanying the use of nuclear energy. Our group has been analyzing various aspects of demerits of nuclear energy including radiological consequences of the nuclear accidents such as TMI-2 (USA 1979), Chernobyl-4 (USSR 1986) etc. In these years we have been concentrating our efforts on the study of the consequences of Chernobyl NPPfs Accident.
Publications:
H. Koide et.al.; Energy and Human Being, Tokyo-Kyogakusya, 1995(in Japanese).
T. Imanaka; Gijutsu-to-Ningen, Vol. 24, April 1995 (in Japanese).
T. Imanaka; Sekai, Vol. 623, June 1996 (in Japanese).
V. P. Matsko, T. Imanaka; J. Health Physics, Vol. 32 No.1, 1997.
I.A. Ryabtsev, T. Imanaka; J. Health Physics, Vol. 32 No.2, 1997.
T. Imanaka, H. Koide et.al.; Proc. 32nd Sci. Meeting KURRI, January 1998 (in Japanese).
T. Imanaka ed.; KUR Report, KURRI-KR-21, 1998.