Katsuyoshi Tatenuma

A 99mTc generator using a new inorganic polymer adsorbent for (n, γ) 99Mo

Abstract A 99mTc generator has been prepared using an inorganic polymer adsorbent newly developed for low specific activity 99Mo. The adsorbent (PZC) was synthesized from zirconium chloride and isopropyl alcohol on heating. To adsorb 99Mo, PZC was added to the solution of 99Mo prepared from neutron-irradiated natural MoO3. The amount of 99Mo (Mo) adsorbed to PZC reached about 200 mg/g-PZC. Technetium-99m was eluted with a small volume of saline solution in the yield of about 80%. The breakthrough of 99Mo was less than 0.5% in good conditions.

Newly developed decontamination technology based on gaseous reactions converting to carbonyl and fluoric compounds

A new gas-phase decontamination technology is developed based on gaseous reactions utilizing the volatile properties of the carbonyl and fluoric compounds of radioactive transition elements and actinides (corrosion products, fission products, and transuranium) on a materials surface. The feasibility of this new technology is determined by removing nonradioactive (Co, Cr, Ni, Re, Mo, Mn, Ru, and Zn) and radioactive ( 60 Co, 63 Ni, and 103 Ru) nuclide transition elements as gaseous forms under high CO pressure (50 to 200 atm) and high temperature (∼350°C). Experiments involving U and using fluoric gases are also performed. For radioactive nuclides existing in an oxide layer of stainless steel, pretreatment with supercritical CO 2 + I 2 + H 2 O is used to remove the oxide layer completely, and by the subsequent gaseous reaction, 95 to 99% of 60 Co is removed from the layer by CO gas treatment at a pressure of 200 atm. The plasma treatment using fluorine gas results in U being removed with high efficiency (∼60%) after only 5 min, even at a reduced pressure of I Torr and at room temperature. When the carbonyl and fluoric species generated from a nontoxic gas mixture (1 Torr) of CF 4 and O 2 is used, U and 60 Co are removed simultaneously with high removal efficiencies of 80 and 100% for 60 Co and U, respectively. The data provide evidence that chemically reactive plasma treatment is available as a gas-phase decontamination method that can be conducted using nontoxic gases under safe and mild conditions such as reduced pressure, shorter time periods, and ambient temperature. Finally, a fluoric chemical reaction can be used to remove solid U deposits by converting them to gaseous U compounds at room temperature and without using plasma treatment. The pressure of ClF 3 gradually affects the higher removal efficiency of U, and the removal efficiency is >90% under the conditions of 30 min and >100 Torr. The results verify that chemical reactions involving carbonylation and fluorination reactions can be utilized for gas-phase decontamination, and the potential for this new idea for decontamination is affirmed. If gas-phase decontamination technology is further developed, it will be not only convenient but also economically advantageous because decontaminating and treating the large volume of nuclear wastes-especially nonincinerable radioactive wastes-are currently very difficult.

Development of Tritium Release Apparatus Using Pulse Mode Heating

Tritium release apparatus with the function of pulse mode heating was developed by using the infrared ray furnace to demonstrate the pulse mode heating of tritium breeder blanket for the fusion reactor. This apparatus was installed in the glove box of the beryllium PIE facility that constructed the hot-laboratory of Japan Materials Testing Reactor. The performance of this apparatus is that the minimum time of rapid heating up to 1015 {degree}C is about 119 s and maximum heating rate reached at 1000 {degree}C/min. The maximum temperature depends on the crucible materials because of the differences for infrared ray absorption. The conversion efficiency of the gaseous water by ceramic electrolysis cell is above 99.99%. The pulse mode heating of the tritium breeder and neutron multiplier materials of the blanket could be demonstrate by using this apparatus. 7 refs., 7 figs., 1 tab.