Establishment of experimental system for Mo/Tc production by neutron activation method

Ishida, Takuya; Shiina, Takayuki*; Ota, Akio*; Kimura, Akihiro; Nishikata, Kaori; Shibata, Akira; Tanase, Masakazu*; Kobayashi, Masaaki*; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.

JAEA-Technology 2015-030, 42 Pages, 2015/11

JAEA-Technology-2015-030.pdf:4.82MB

The research and development (R&D) on the production of Mo/Tc by neutron activation method ((n, ) method) using JMTR has been carried out in the Neutron Irradiation and Testing Reactor Center. The specific radioactivity of Mo by (n, ) method is extremely low compared with that by fission method ((n,f) method), and as a result, the radioactive concentration of the obtained Tc solution is also lowered. To solve the problem, we propose the solvent extraction with methyl ethyl ketone (MEK) for recovery of Tc from Mo produced by (n, ) method. We have developed the Mo/Tc separation/extraction/concentration devices and have carried out the performance tests for recovery of Tc from Mo produced by (n, ) method. In this paper, in order to establish an experimental system for Mo/Tc production, the R&D results of the system are summarized on the improvement of the devices for high-recovery rate of Tc, on the dissolution of the pellets, which is the high-density molybdenum trioxide (MoO) pellets irradiated in Kyoto University Research Reactor (KUR), on the production of Tc, and on the inspection of the recovered Tc solutions.

Dependence of the yields of AP sites and AP clusters produced in plasmid DNA on scavenging capacity and LET

Shiina, Takuya*; Watanabe, Ritsuko; Suzuki, Masao*; Yokoya, Akinari

Journal of Radiation Research, 55(Suppl.1), p.i15 - i16, 2014/03

BB2013-0476.pdf:0.21MB

https://doi.org/10.1093/jrr/rrt160

Improvement of the center boring device for the irradiated fuel pellets

Toyokawa, Takuya; Usami, Koji; Shiina, Hidenori; Onozawa, Atsushi

Proceedings of 49th Conference on Hot Laboratories and Remote Handling (HOTLAB 2012) (Internet), 6 Pages, 2012/09

http://hotlab.sckcen.be/en/Proceedings

Dependence of the yields of AP sites and AP clusters produced in pUC18 plasmid DNA on scavenging capacity and radiation quality

Shiina, Takuya; Sugaya, Yuki; Shiraishi, Iyo; Watanabe, Ritsuko; Yokoya, Akinari

no journal, , 

Many studies using synthetic AP clusters reported that AP clusters retard base excision repair processes. Sutherland et al. (2002) showed that AP clusters are induced efficiently in human cells by low LET X-irradiation with the similar yields with those for the pyrimidine or purine base lesion clusters. There, however, has been very little knowledge of AP sites and AP clusters induced by high LET radiation. In order to clarify the relation between track structure of C ions or X-rays and the induction processes of an AP or AP clusters, we measure the yield of AP sites visualized by the treatment of irradiated pUC18 plasmid DNA with the AP endoclease (Nfo), which converts an AP site to detectable single strand break. Several scavenging capacities of the samples are tested to estimate the effect of indirect action of diffusible OH radicals. These experimental data will be discussed with theoretical radiation track structure in the respect of repair susceptibility of the AP cluster.

Analysis of spatial distribution of DNA damage around the radiation track

Watanabe, Ritsuko; Shiina, Takuya*; Yokoya, Akinari

no journal, , 

We have estimated the initial DNA damage spectrum by track structure simulation method. The result shows that the increase of the complexity of initial DNA damage and cell lethality show partially similar trend in their LET dependence. The goal of our study is to elucidate and modeling the relationship between initial DNA damage and radiation-induced cellular response by using the calculated DNA damage spectrum. For this purpose, the spatial distribution of the damage in larger scale should be considered. In this presentation, in addition to the damage spectrum, the spatial distribution of each type of DNA damage around the radiation track will be shown. The simulated DNA damage spectrum and the spatial distribution such as the distance between two clustered DNA damages in chromosome domain in cell nucleus model was discussed in comparison with the yield of lethal damage estimated from the experimentally obtained survival curves.

Order effect of base excision processes to repair clustered DNA damage, 2

Shiraishi, Iyo; Shiina, Takuya; Sugaya, Yuki; Shikazono, Naoya; Yokoya, Akinari

no journal, , 

Cellular response to cluster DNA damage might depend on the order of repair processes because the configuration of the lesions will be modified by the reaction of the initial repair protein, affecting the DNA-binding or lesion-excision activities of the latter repair protein. In the present study, we investigate how the initial enzymatic repair affects the activity of the latter repair enzyme. Plasmid DNA (pUC18) irradiated with C6+ ion is treated with two base excision repair enzymes, Nth and Fpg, which convert pyrimidine and purine lesions to a SSB. The enzymatic activities are quantified by measuring the conformational changes of the plasmid using agarose gel electrophoresis. Obtained results show that the amount of enzymatically induced SSB is slightly (about 5%) less in DNA sample treated with Nth first and then Fpg than that in the sample treated with Fpg first and then Nth. The repairability of clustered damage induced by high-LET ions will be discussed.

Development of extraction and concentration system of Tc from Mo produced by (n,) method

Tanase, Masakazu*; Shiina, Takayuki*; Ota, Akio*; Fujisaki, Saburo*; Kawauchi, Yukimasa*; Kimura, Akihiro; Nishikata, Kaori; Yonekawa, Minoru; Ishida, Takuya; Kato, Yoshiaki; et al.

no journal, , 

Preliminary studies for obtaining Tc from, (n,)Mo produced in JMTR has been carried out, as a part of the industrial use expansion after JMTR will re-start. In order to obtain high specific-volume of Tc, a method was proposed for extracting Tc with MEK, followed by purification and concentration with acidic and basic alumina. In this study, preliminary tests, aiming construction of production system, were carried out using Re instead of Tc because Re and Tc are homologous elements. The average recovery yield of Re was very high to be 98%. Based on the result, an apparatus for Tc production was assembled.

Variation in DNA damage induced by monochromatic soft X-rays in the energy region of oxygen K-edge

Sugaya, Yuki; Shiina, Takuya; Shiraishi, Iyo; Fujii, Kentaro; Yokoya, Akinari

no journal, , 

no abstracts in English

Simulation study of microdosimetry and distribution of DNA damage including base damage

Watanabe, Ritsuko; Shiina, Takuya*; Yokoya, Akinari

no journal, , 

This study aims to examine and develop the production models of base damage in order to obtain the detail of the spectrum of initial DNA damage consisting of strand breaks and base lesions. Monte Carlo track structure code for ions TRACION and the DBREAK code system were used for the simulation for irradiation by photons and ions. The number and configuration of lesions on the DNA segment within a few tens base pairs length were estimated. In the presentation, the tested results will be compared with some available experimental data and examine. The detail of the positional distribution of damages which may be related to the inhibition of repair processing will be presented. In addition, the obtained DNA damage spectrum will be discussed related to not only LET but also microdosimetric quantities as specific energy or linear energy.

Dependence of the yields of AP sites and AP clusters in plasmid DNA on radiation quality and LET

Shiina, Takuya; Shiraishi, Iyo; Sugaya, Yuki; Watanabe, Ritsuko; Suzuki, Masao*; Yokoya, Akinari

no journal, , 

no abstracts in English