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Oral presentation

Reduction and resource recycling of high-level radioactive wastes through nuclear transformation; Theoretical predictions of the nuclear reaction data for nuclei involved in the nuclear transformation system

Furutachi, Naoya; Minato, Futoshi; Iwamoto, Osamu

no journal, , 

For the feasibility study of the nuclear transmutation system for the long-lived fission products(LLFPs), the simulation calculation to estimate the efficiency of the transmutation system is essential. The precision of the simulation calculation largely depends on the evaluated nuclear data used in the calculation. To improve the precision of the simulation calculation, developing nuclear data not only of LLFPs but also of all the nuclei involved in the simulation calculation is desirable. When we study the transmutation system using the nuclear reaction such as spallation reaction, it is anticipated that a wide range of nuclei including unstable nuclei with no or scarce experimental are produced. In particular, the shortage of nuclear experimental data in resonance region is a problem for nuclear data evaluation, because it is difficult to predict the resonant structure precisely in a theoretical way. One of the methods mitigating this problem is to use the resonance parameters randomly determined from the statistical properties of the resonance parameters. This approach is already adopted in TENDL nuclear data library. However, the cross section calculated using such a method would have a large uncertainty arising from the statistical fluctuation of the resonance parameters in principle. This uncertainty wasn't discussed in the previous study. In this study, we investigated the statistical method to predict the nuclear reaction data in resonance region focusing on its statistical uncertainties. Particularly, we shall discuss the neutron capture cross sections of nuclei expected to be produced via the transmutation of Se-79, Zr-93, Pd-107 and Cs-135.

Oral presentation

Study on cleaning performance for sludge in a centrifugal contactor

Sakamoto, Atsushi; Sano, Yuichi; Takeuchi, Masayuki; Matsuura, Takanobu*; Sakamoto, Yukio*; Sekita, Satoshi*

no journal, , 

In the present study, cleaning performance for sludge in a centrifugal contactor was investigated experimentally. It was confirmed that the splay nozzle could reduce the volume of washing solution and cleaning time significantly, compared with the cleaning without spray nozzle.

Oral presentation

Development of computer simulation technology in JAEA for study on new solvent extraction processes

Tsubata, Yasuhiro; Suzuki, Hideya; Matsumura, Tatsuro

no journal, , 

In JAEA, research and development activity in simulation technology for solvent extraction processes has been continued for many years. In our laboratory, a computer program PARC has been developed and used for experimental studies on multistage extraction processes. In this paper, outline of the process simulation technology in the JAEA are introduced.

Oral presentation

Adsorption behavior of europium, cerium and antimony on ammonium molybdophosphate

Onishi, Takashi; Sekioka, Ken*; Suto, Mitsuo*; Tanaka, Kosuke; Katsuyama, Kozo

no journal, , 

In order to establish simple methods for selective removal of cesium by ammonium molybdophosphates for $$gamma$$-ray spectrometry, adsorption behavior of europium, cerium and antimony on ammonium molybdophosphate were investigated.

Oral presentation

Reduction and resource recycling of high-level radioactive wastes through nuclear transformation; Extraction of Pd, Zr, Se and Cs having long lived radionuclides

Sasaki, Yuji; Morita, Keisuke; Suzuki, Shinichi; Shiwaku, Hideaki; Ito, Keisuke; Takahashi, Yuya*; Kaneko, Masaaki*

no journal, , 

Pd, Zr, Se, and Cs have very long lived radioactivities. These are the aimed elements to recover from high level radioactive waste and transmutated in order to reduce the environmental burden. All metals aimed show the different chemical behavior, so the different conditions for the recovery have to be set up. The solvent extractions of Se, Zr, Pd and Cs from nitric acid into 1-octanol are performed. It was found that Se, Zr and Pd can be extracted by phenylenediamine, TODGA, and NTAamide, respectively. In addition, Cs can be extracted up to 56% by di-t-butyl-dibenzo-18-crown-6.

Oral presentation

Recent progress of R&D on accelerator-driven system in JAEA

Sugawara, Takanori; Takei, Hayanori; Iwamoto, Hiroki; Oizumi, Akito; Nishihara, Kenji; Tsujimoto, Kazufumi

no journal, , 

The Japan Atomic Energy Agency (JAEA) has investigated an accelerator-driven system (ADS) to transmute minor actinides which will be partitioned from the high level waste. There are various inherent issues for the research and development on the ADS. The recent two activities to realize a feasible and reliable ADS concept are introduced in this paper. For the feasibility, the beam window design is one of the most important issues. To mitigate the design condition of the beam window, namely to reduce the proton beam current, the subcritical core concepts with subcriticality adjustment rods were investigated. For the reliability, the double-accelerator concept was proposed to reduce the beam-trip frequency.

Oral presentation

Raman spectroscopy of (U, Ce)O$$_{2-x}$$

Watanabe, Masashi; Kato, Masato; Sunaoshi, Takeo*; Yato, Tadao*; Konashi, Kenji*

no journal, , 

Raman spectroscopy has been used to detect the oxygen vacancies and proven to be a very powerful characterization technique. Recently, Raman spectra were measured for UO$$_{2+x}$$, but the Raman spectral data of hypo-stoichiometric actinide oxides are limited. The present work demonstrated that the Raman microscopy could successfully be used to detect the Raman spectra of non-stoichiometric (U, Ce)O$$_{2}$$.

Oral presentation

Continuous extraction and separation of Am(III) and Cm(III) using a highly practical alkyl diamide amine ligand

Suzuki, Hideya; Tsubata, Yasuhiro; Kurosawa, Tatsuya; Sagawa, Hiroshi; Matsumura, Tatsuro

no journal, , 

Alkyl diamide amine (ADAAM), a highly practical reagent with a simple structure, was evaluated for the separation of Am(III) and Cm(III). ADAAM is a multidentate ligand comprising one soft N-donor atom and two hard O-donor atoms as part of its central frame. This tridentate set of donor atoms provide selective binding for Am(III) and Cm(III) in highly acidic media and yield separation factors of up to 5.5. A continuous liquid-liquid extraction and stripping process were performed using ADAAM in n-dodecane as the extractant in a multistage countercurrent mixer-settler extractor. Separation of Am(III) and Cm(III) in very high yield was demonstrated.

Oral presentation

Progress in domestic securement of Pu standard material

Motoki, Chika*; Furuta, Koya*; Yamaguchi, Kazuya*; Saito, Shingo*; Fujiwara, Hideki*; Shibano, Koya; Sumi, Mika; Kageyama, Tomio

no journal, , 

Certified Reference Materials (CRMs) of uranium and plutonium are necessary to perform Isotope Dilution Mass Spectrometry (IDMS) for nuclear material accountancy. Qualified Pu standard Material is a highly precious resource on a global scale. Therefore domestic securement of the material is strongly desired. JNFL entrust the development of preparation technique of Pu standard material to JAEA. Recently, purified Pu nitrate solution from MOX powder stored at JAEA was characterized. The framework for certification is presented in this brief.

Oral presentation

Separation of palladium from high-level liquid waste by extraction with 5,8-diethyl-7-hydroxy-6-dodecanone oxime

Morita, Yasuji; Yamagishi, Isao

no journal, , 

Separation of palladium from high-level liquid waste (HLLW) by extraction with 5,8-diethyl-7- hydroxy-6-dodecanone oxime (DEHDO) was studied through batch and continuous extraction tests using simulated HLLW, which showed possibility to establish selective separation process for Pd.

Oral presentation

Study on transmutation of radioactive iodine in fast reactors

Tachi, Yoshiaki; Wakabayashi, Toshio*; Takaki, Naoyuki*

no journal, , 

In order to minimize risks caused by radioactive waste, we have stared research and development on transmutation of radioactive iodine using fast reactor. Iodine-129 is one of long-lived fission products and it is dominant nuclide having an influence on future public radiation exposure after radioactive waste disposal. Iodine-129 will be transmuted efficiently by neutrons of fast reactor, thereby reliability of geological disposal of radioactive waste will be improved.

Oral presentation

Recent progress on R&D of reprocessing and minor actinide separation process with innovative extractants in CHON principle

Matsumura, Tatsuro; Ban, Yasutoshi; Suzuki, Hideya; Tsubata, Yasuhiro; Hotoku, Shinobu; Tsutsui, Nao; Suzuki, Asuka

no journal, , 

The new reprocessing and minor actinide (MA) separation processes using innovative extractants in accord with CHON principle has been developed in Japan Atomic Energy Agency aimed for reduction of radioactive wastes from nuclear fuel cycle. The new nonorganophosphorus extractants which have appropriate extraction behaviors for each separation steps were developed. Continuous counter-current experiment of each solvent extraction process with uranium, plutonium and tracers of minor actinides were carried out. The experimental results showed that the separation performance of the solvent extraction processes were demonstrated successfully.

Oral presentation

Degradation behaviors of the TODGA/SiO$$_{2}$$-P adsorbent for extraction chromatography

Miyazaki, Yasunori; Watanabe, So; Sano, Yuichi; Kofuji, Hirohide; Takeuchi, Masayuki; Ishigami, Ryoya*

no journal, , 

Extraction chromatography has been employed to separate minor actinides (MAs) from spent nuclear fuel for the purpose of reducing environmental impact. In our strategy, the polymer-coated SiO$$_{2}$$ particle with an extractant is packed in a column and utilized for group separation and/or isolation of the specific element (Am and Cm, for example) from high level liquid waste. The safety use of chromatography was assessed by irradiation to the adsorbent with He$$^{2+}$$ beam and $$gamma$$ ray to simulate the high-level nuclear waste. In this study, we focused on a recently developed extractant TODGA and its degradation behavior on top of the SiO$$_{2}$$-P adsorbent was investigated by a similar experimental manner.

Oral presentation

Evaluation of the flowsheet with TDdDGA by counter-current trials using mixer-settlers and centrifugal contactors

Sano, Yuichi; Kibe, Satoshi; Sakamoto, Atsushi; Takeuchi, Masayuki; Suzuki, Hideya; Tsubata, Yasuhiro; Matsumura, Tatsuro

no journal, , 

The flowsheet with TDdDGA extractant for recovering MA(III) from PUREX raffinate was evaluated by counter-current trials with surrogate PUREX raffinate using mixer-settlers and centrifugal contactors. The extraction and back-extraction of Ln(III) which show the similar tendencies as MA(III) could be achieved successfully, especially their back-extraction proceeded more efficiently in centrifugal contactors, which might be due to superior phase separation performance of centrifugal contactors.

Oral presentation

Ceramography and EPMA investigation of irradiation behavior of annular MOX pellets

Sasaki, Shinji; Isozaki, Misaki; Ishimi, Akihiro; Maeda, Koji

no journal, , 

Fuel rods containing annular MOX pellets were irradiated at over 400 W/cm to burnup of nearly 30,000 MWd/t in the experimental fast reactor, Joyo. The microstructural change and redistribution of Pu and U in the pellets were investigated by ceramography and EPMA.

Oral presentation

The Effect of O/M ratio on inter-diffusion of uranium and plutonium in MOX fuel

Matsumoto, Taku; Morimoto, Kyoichi; Kato, Masato; Tamura, Tetsuya*; Uno, Hiroki*

no journal, , 

The O/M ratio dependence on inter-diffusion of uranium and plutonium was evaluated by isothermal diffusion tests using diffusion couples consisting of (U$$_{0.51}$$Pu$$_{0.46}$$Am$$_{0.03}$$)O$$_{2-x}$$ and UO$$_2$$ disks. The inter-diffusion coefficient at O/M = 1.992 was about two orders of magnitude greater than that at O/M = 1.942. In addition, significant grain boundary diffusion was observed at O/M = 1.992.

Oral presentation

Evaluation of condensation behavior for vaporized FP species

Takai, Toshihide; Sato, Isamu*; Yamashita, Shinichiro; Furukawa, Tomohiro

no journal, , 

Aerosols are produced when the vapor species released from overheated fuels are transported to reactor cooling system under severe accident. The chemical forms of the aerosol may be determined a region between the vapors release and the aerosols formation. No information is available about the chemical forms in the region. The using of hypothesis chemical forms in source term evaluation becomes one of the causes of uncertainty. For the improving evaluation accuracy, it is necessary to obtain the chemical forms data in the region. Applicability of a cascade impactor was investigated to determine the material properties of right after the aerosol formation, because it had possibility to collect aerosols in the classified stage in each particle size and determine the material properties for each stage.

Oral presentation

Study on the condition of MOX granules suitable for constant die filling in MOX fuel pellet production

Akashi, Masatoshi; Nishina, Masahiro; Morimoto, Kyoichi; Kato, Yoshiyuki; Kato, Masato

no journal, , 

A die filling experiment was carried out using granulated MOX powder to investigate the condition of MOX granules suitable for constant die filling. It was found that the mean particle diameter and the Hausner ratio gave an indication of the die filling for the granulated MOX powder.

Oral presentation

Recent activity on R&D of pyrochemical treatment of spent nitride fuels for MA transmutation in JAEA

Hayashi, Hirokazu; Sato, Takumi; Shibata, Hiroki; Tsubata, Yasuhiro

no journal, , 

This paper overviews current status and recent activity on development of pyrochemical treatment of spent nitride fuels for MA transmutation in JAEA. Recent studies devoted to the development of the anode suitable for nitride fuels, from which nitrogen gas is released by the electrorefining, and that of the renitridation apparatus suitable for scale-up.

Oral presentation

Current status of SmART cycle project in JAEA

Watanabe, So; Sano, Yuichi; Kofuji, Hirohide; Takeuchi, Masayuki; Tanaka, Kosuke; Koizumi, Tsutomu; Mizuno, Tomoyasu; Kihara, Yoshiyuki

no journal, , 

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