Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Tamada, Masao; Seko, Noriaki; Kasai, Noboru; Shimizu, Takao*
FAPIG, (169), p.3 - 12, 2005/03
Braid adsorbent having functional group of amidoxime is a promising material for the recovery of uranium dissolved in the seawater. This braid adsorbent was made by polyethylene multi-fibers in which amidoxime groups were introduced by radiation-induced graft polymerization and subsequent chemical treatment. Reaction time for graft polymerization was 5 h and the resulted braid adsorbent had 2.8 mmol/g-adsorbent of amidoxime group. The braid adsorbent obtained was moored at the offing of Okinawa Island. The adsorption of uranium reached 1.5g/kg-adsorbent for 30 d soaking. The mooring system for braid adsorbent has possibility which reduced the cost for the recovery of uranium from seawater. It is shown that 134 km
of mooring area is needed for annual product of 1200 tons of uranium. In addition, there is 6000 km and more of suitable sea area for the collection of the uranium in the regions from Okinawa Islands to Tosa Bay in Japan.
Kumata, Masahiro; Oda, Tetsuzo; Miyamoto, Yutaka; Uchikoshi, Takako*; Nakahara, Yoshinori; Yamamoto, Yoichi; Hokida, Takanori; Hirota, Naoki*; Inoue, Yoji; Shinohara, Nobuo
Dai-23-Kai Kaku Busshitsu Kanri Gakkai Nihon Shibu Nenji Taikai Rombunshu, p.39 - 44, 2002/12
The International Monitoring System (IMS) will be established across the world to verify compliance with the Comprehensive Test Ban Treaty (CTBT). The IMS will be capable of detecting and identifying nuclear explosions of detonated within the atmosphere, underwater and underground. 321 monitoring stations will be set around the world as a monitoring network of the IMS. The four technologies of seismology, hydroacoustic, infrasound, and radionuclide will be used for monitoring purposes. In order to build the radionuclide monitoring network, 80 radionuclide stations were chosen. Particles in the atmosphere are collected on a filter at each station to measure radioactivity by a HP-Ge detector. Further, 40 out of these 80 stations will be equipped with an automatic radioactive noble gas sampler/analyzer. The JAERI is establishing infrastructure to host radionuclide air monitoring equipment for two raionuclide stations in Japan. This paper presents the current status of the establishment and promising performance of the stations in Japan.
Shimizu, Takao*; Tamada, Masao; Seko, Noriaki; Sakaguchi, Isamu*
Kaiyo Kaihatsu Rombunshu, 18, p.737 - 742, 2002/06
Total amount of uranium in seawater is 4.5 billion tons corresponding to 45,000 times of annual demand for nuclear fuel in the world, though its concentration is only 3.3 mg/m3. The target of this study is that the cost-down of uranium collection from the sea to three times of the market price. This price is cheaper than the recycle fuel by nuclear reprocessing. The present study proposed a high performance adsorbent made by means of both radiation induced graft polymerization and braid technique. The drag force of the braid type adsorbent in water channel was measured. In the west coast of Okinawa prefecture, the adsorption of uranium and the adhesion of sea creature were investigated. It was clarified that reduction of the drag force by the deformed braid adsorbent in the water flow, the increment of uranium adsorption owing to high temperature of seawater, and little adhesion of the creature.
Tomita, Yutaka; Kijima, Yuichi; Furuno, Akiko; Yamamoto, Yoichi
no journal, ,
The Japan Atomic Energy Agency (JAEA) has operated two radionuclide stations which are Takasaki radionuclide station (RN38) and Okinawa radionuclide station (RN37) for the CTBT (Comprehensive Nuclear- Test-Ban Treaty) International Monitoring System (IMS). RN38 was built in the Takasaki Advanced Radiation Research Institute of the National Institutes for Quantum and Radiological Science and Technology (QST) in 2002. Radioactivity of particulate radionuclides and radioxenon gases are measured at RN38 by using a Radionuclide Aerosol Sampler / Analyzer (RASA) and a Swedish Automatic Unit for Noble Gas (SAUNA) respectively. It was worthy of special mention that the SAUNA of RN38 detected the radioxenons which were related to the DPRK-3 event in 2013. RN37 was installed in a renovated facility at the Okinawa Tracking and Communication Station of the Japan Aerospace Exploration Agency (JAXA) in 2006. It measures only radioactivity of particulate radionuclides by using a RASA. JAEA contributes to the CTBT international verification regime through these activities. Operation and some monitoring results of both radionuclide stations will be reported in this presentation.
Tomita, Yutaka; Furuno, Akiko; Yamamoto, Yoichi
no journal, ,
Various restrictions under the COVID-19 crisis have been imposed on the operation and maintenance of the radionuclide stations of RN37 and RN38 in Japan. We will report on how JAEA is working with PTS, manufacturers of RASA and SAUNA, and local operators in order to overcome this challenge.
Tomita, Yutaka; Furuno, Akiko; Kurihara, Toshiyuki; Yamamoto, Yoichi; Sakurai, Shinichi*
no journal, ,
There are the two IMS radionuclide stations, RN37 Okinawa and RN38 Takasaki, in Japan. JAEA (Japan Atomic Energy Agency) has been operating both of the stations. RN37 Okinawa has been observing for more than 15 years without long missing periods since received the certification in February 2007. RN37 Okinawa is located in the subtropical zone and close to the sea. Therefore, the station building and equipment are susceptible to corrosion due to high temperature, high humidity, and salt damage. This makes maintenance more difficult than that of RN38 Takasaki which is located inland in the temperate zone. In this presentation, we will report on O&M specific for the RN37 Okinawa, including measures against salt damage, lightning, and humidity, etc.
