Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Shimizu, Takao*; Tamada, Masao
Kaiyo Kaihatsu Rombunshu, 20, p.617 - 622, 2004/06
Recovery system of braid type adsorbent which stands straight with built-in float from sea bottom was proposed on the points of effective and economical view. The system scale for 1200 t/y recovery (demand for 6 atomic power plants) with braid type adsorbent was optimized by a model in which the efficiency of uranium adsorption was proportional to the uranium concentration surrounding the adsorbent. The recovery system of 2.67 millions adsorbents which were arranged with the distance of more than 60m intervals among the adsorbents could collect 1200t/y uranium. The system still collected 1000 t/y uranium when the interval distance decreased to 4 m. The area occupied by the adsorbents was 6.5 km square. The sea area on the coast of Japan was searched for recovery system of braid type adsorbent by considering the factors of the temperature, the depth, the fishery, and the territorial waters of Japan. The selected sea area was located form the South East Islands to the offing of Koch in the depth range from 100m to 200m, where the Japan Current flew.
Seko, Noriaki; Tamada, Masao; Kasai, Noboru; Yoshii, Fumio; Shimizu, Takao*
Kaiyo Kaihatsu Rombunshu, 20, p.611 - 616, 2004/06
Development of the recovery technology of uranium of storing all over seawater can stable supply of mineral resources over the future. The amidoxime adsorbents used by nonwoven fiber of the shape of cloth produced by the radiation graft polymerization technique. It became clear that their adsorbents of the high form of contact efficiency with seawater are important. Therefore, the braid adsorbents by which contact efficiency with seawater is improved were devised. Moreover, by the mooring system using braid adsorbents, since it counted upon lightweight-ization, i.e., rationalization of the marine structure which occupies the great portion of total cost, in this research, while developing the producing method, performance evaluation was performed, and the production method and the applicability of a recovery system were examined.
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.
