Stabilization treatment of nuclear fuel material contained with organic matter

Senzaki, Tatsuya; Arai, Yoichi; Yano, Kimihiko; Sato, Daisuke; Tada, Kohei; Ogi, Hiromichi*; Kawanobe, Takayuki*; Ono, Shimpei; Nakamura, Masahiro; Kitawaki, Shinichi; et al.

JAEA-Testing 2022-001, 28 Pages, 2022/05

JAEA-Testing-2022-001.pdf:2.33MB

In preparation for the decommissioning of Laboratory B of the Nuclear Fuel Cycle Engineering Laboratory, the nuclear fuel material that had been stored in the glove box for a long time was moved to the Chemical Processing Facility (CPF). This nuclear fuel material was stored with sealed by a polyvinyl chloride (PVC) bag in the storage. Since it was confirmed that the PVC bag swelled during storage, it seems that any gas was generated by radiolysis of the some components contained in the nuclear fuel material. In order to avoid breakage of the PVC bag and keep it safety for long time, we began the study on the stabilization treatment of the nuclear fuel material. First, in order to clarify the properties of nuclear fuel material, radioactivity analysis, component analysis, and thermal analysis were carried out. From the results of thermal analysis, the existence of organic matter was clarified. Then, ion exchange resin with similar thermal characteristics was selected and the thermal decomposition conditions were investigated. From the results of these analyzes and examinations, the conditions for thermal decomposition of the nuclear fuel material contained with organic matter was established. Performing a heat treatment of a small amount of nuclear fuel material in order to confirm the safety, after which the treatment amount was scaled up. It was confirmed by the weight change after the heat treatment that the nuclear fuel material contained with organic matter was completely decomposed.

"Crystal lattice engineering", an approach to engineer protein crystal contacts by creating intermolecular symmetry; Crystallization and structure determination of a mutant human RNase 1 with a hydrophobic interface of leucines

Yamada, Hidenori*; Tamada, Taro; Kosaka, Megumi*; Miyata, Kohei*; Fujiki, Shinya*; Tano, Masaru*; Moriya, Masayuki*; Yamanishi, Mamoru*; Honjo, Eijiro; Tada, Horiko*; et al.

Protein Science, 16(7), p.1389 - 1397, 2007/07

https://doi.org/10.1110/ps.072851407

In an attempt to control protein incorporation in a crystal lattice, a leucine zipper-like hydrophobic interface (comprising four leucine residues) was introduced into a helical region (helix 2) of the human pancreatic ribonuclease 1 (RNase 1) that was predicted to form a suitable crystallization interface. Although crystallization of wild type RNase 1 has not yet been reported, the RNase 1 mutant having four leucines (4L-RNase 1) was successfully crystallized under several different conditions. The crystal structures were subsequently determined by X-ray crystallography by molecular replacement using the structure of bovine RNase A. The overall structure of 4L-RNase 1 is quite similar to that of the bovine RNase A, and the introduced leucine residues formed the designed crystal interface. To further characterize the role of the introduced leucine residues in crystallization of RNase 1, the number of leucines was reduced to three or two (3L- and 2L-RNase 1, respectively). Both mutants crystallized and a similar hydrophobic interface as in 4L-RNase 1 was observed. A related approach to engineer crystal contacts at helix 3 of RNase 1 (N4L-RNase 1) was also evaluated. N4L-RNase 1 also successfully crystallized, and formed the expected hydrophobic packing interface. These results suggest that appropriate introduction of a leucine zipper-like hydrophobic interface can promote intra molecular symmetry for more efficient protein crystallization in crystal lattice engineering efforts.

Research and development of a method to remove chloride ions from liquid waste including U and Pu

Tada, Kohei; Kitawaki, Shinichi; Watanabe, So; Hinai, Hiroshi; Shibata, Atsuhiro; Nomura, Kazunori

no journal, , 

no abstracts in English

Co-precipitation for U and Pu onto Solid Cathode by Electrorefining in molten salt

Tada, Kohei; Kitawaki, Shinichi; Sakamura, Yoshiharu*; Murakami, Tsuyoshi*

no journal, , 

no abstracts in English

Details of research and development for pyrochemical reprocessing in JAEA

Kofuji, Hirohide; Tada, Kohei; Kitawaki, Shinichi; Hayashi, Hirokazu; Murakami, Tsuyoshi*; Sakamura, Yoshiharu*

no journal, , 

Metal electrorefining technology which is the most promising method of pyro-reprocessing has been developed in JAEA under the collaboration with CRIEPI. Through the research and development, feasibility of the process had been confirmed and design of process equipment and facility has been progressed. Technology would be expected suitable for the future nuclear fuel cycle concept which will be focused on reduction of environmental burden of the radioactive waste.

Pyroprocessing technology development for flexible introduction of fast reactor fuel cycle

Iizuka, Masatoshi*; Nohira, Toshiyuki*; Tada, Kohei; Murakami, Tsuyoshi*; Kofuji, Hirohide

no journal, , 

Development of highly flexible technology for recovery and transmutation of minor actinide

Tada, Kohei; Kofuji, Hirohide; Murakami, Tsuyoshi*

no journal, , 

no abstracts in English