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JAEA Reports

Study on radionuclide analysis of rubble and plants for decommissioning of Fukushima Daiichi Nuclear Power Station

Seki, Kotaro; Sasaki, Takayuki*; Akimoto, Yuji*; Tokunaga, Takahito; Tanaka, Kiwamu; Haraga, Tomoko; Ueno, Takashi; Ishimori, Kenichiro; Hoshi, Akiko; Kameo, Yutaka

JAEA-Technology 2016-013, 37 Pages, 2016/07

JAEA-Technology-2016-013.pdf:2.09MB

In this study, based on the simple and rapid analytical method established from the wastes from research facilities, we created analytical schemes which is applicable to rubble and plants collected at Fukushima Daiichi, then transported to Nuclear Science Research Institute of JAEA. We examined the applicability, and confirmed quantifiability of radioactivity concentration with high recovery rate without being affected by fission products such as $$^{90}$$Sr and $$^{137}$$Cs.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities, 4

Omori, Hiroyuki; Nebashi, Koji; Shimada, Asako; Tanaka, Kiwamu; Yasuda, Mari; Hoshi, Akiko; Tsuji, Tomoyuki; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2014-029, 31 Pages, 2015/03

JAEA-Data-Code-2014-029.pdf:1.51MB

Simple and rapid methods to evaluate the radioactivity concentrations are required for the radioactive waste generated from research facilities in the Japan Atomic Energy Agency to dispose of in a near-surface repository. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid waste generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid waste generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In this report, we reported the analytical data determined in fiscal 2014 ($$^{137}$$Cs and $$^{93}$$Mo) and summarized them with the radioactivity concentrations obtained in the past as basic data to consider the evaluation method of radioactivity concentrations in the stored waste taken from JPDR.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities, 3

Yasuda, Mari; Tanaka, Kiwamu; Watanabe, Koichi; Hoshi, Akiko; Tsuji, Tomoyuki; Kameo, Yutaka

JAEA-Data/Code 2014-011, 59 Pages, 2014/08

JAEA-Data-Code-2014-011.pdf:16.84MB

Simple and rapid methods to evaluate the radioactivity concentrations are required to be established for the near surface disposal of radioactive wastes generated from research facilities at Japan Atomic Energy Agency. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid wastes generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid wastes generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In the present paper, we summarized data about the radioactivity concentrations which accumulated by the analysis.

Journal Articles

Radiochemical analysis of rubble and trees collected from Fukushima Daiichi Nuclear Power Station

Tanaka, Kiwamu; Shimada, Asako; Hoshi, Akiko; Yasuda, Mari; Ozawa, Mayumi; Kameo, Yutaka

Journal of Nuclear Science and Technology, 51(7-8), p.1032 - 1043, 2014/07

 Times Cited Count:16 Percentile:12.97(Nuclear Science & Technology)

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities, 2

Tanaka, Kiwamu; Yasuda, Mari; Watanabe, Koichi; Hoshi, Akiko; Tsuji, Tomoyuki; Higuchi, Hidekazu

JAEA-Data/Code 2013-008, 16 Pages, 2013/11

JAEA-Data-Code-2013-008.pdf:2.41MB

Simple and rapid methods to evaluate the radioactivity concentrations are required to be established for the near surface disposal of radioactive wastes generated from research facilities at Japan Atomic Energy Agency. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid wastes generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid wastes generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In the present paper, we summarized data about the radioactivity concentrations which accumulated by the analysis.

JAEA Reports

Study on the evaluation method to determine the radioactivity concentration in low-level radioactive wastes generated at JPDR facilities, 1

Tsuji, Tomoyuki; Kameo, Yutaka; Sakai, Akihiro; Hoshi, Akiko; Takahashi, Kuniaki

JAEA-Technology 2012-045, 37 Pages, 2013/02

JAEA-Technology-2012-045.pdf:2.43MB

It is necessary to establish practical evaluation methods to determine radioactivity concentrations of the important nuclides for safety assessment on disposal of radioactive wastes in order to dispose of low-level radioactive wastes generated from various nuclear facilities in JAEA. In this report, the practical evaluation methods such as the scaling factor method for JPDR facilities have been studied for disposal of the low-level radioactive wastes generated from nuclear reactor facilities in JAEA.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR facilities

Hoshi, Akiko; Tsuji, Tomoyuki; Tanaka, Kiwamu; Yasuda, Mari; Watanabe, Koichi; Sakai, Akihiro; Kameo, Yutaka; Kogure, Hiroto; Higuchi, Hidekazu; Takahashi, Kuniaki

JAEA-Data/Code 2011-011, 31 Pages, 2011/10

JAEA-Data-Code-2011-011.pdf:1.7MB

Simple and rapid methods to evaluate the radioactivity concentrations are required to be established for the near surface disposal of radioactive wastes generated from research facilities at Japan Atomic Energy Agency. In order to establish the methods to evaluate the radioactivity concentrations of miscellaneous solid wastes generated from research and testing reactors, we collected and analyzed samples from miscellaneous solid wastes generated by the decommissioning of JPDR (Japan Power Demonstration Reactor). In the present paper, we summarized data (262 data) about the radioactivity concentrations of the 7 important nuclides ($$^{3}$$H, $$^{14}$$C, $$^{60}$$Co, $$^{59}$$Ni, $$^{63}$$Ni, $$^{90}$$Sr, $$^{137}$$Cs) which accumulated by the analysis.

JAEA Reports

Clearance of concrete generated from modification activities of JRR-3; Method for measuring and evaluating of radioactivity concentration

Satoyama, Tomonori; Kishimoto, Katsumi; Hoshi, Akiko; Takaizumi, Hirohide; Tsutsumi, Masahiro; Inanobe, Hiroshi; Yoshimori, Michiro

JAEA-Technology 2011-003, 53 Pages, 2011/03

JAEA-Technology-2011-003.pdf:1.6MB

In Nuclear Science Research Institute, clearance activities for extremely low-level radioactive concrete debris, which were generated from the modification activities of JRR-3 from FY 1985 to FY 1989 and now are stored in the waste storage facility NL, have been carried out in order to plan reasonable disposal and effectively reusing of concrete waste, moreover to secure storage capacity at the waste storage facilities. Method for measuring and evaluating of radioactivity concentration was applied for approval of Minister of MEXT on November 8, 2007, approved on July 25, 2008. After that the necessary equipments for clearance works were equipped and operational safety progress and manuals for clearance works were prepared. So clearance works were started in FY 2009. This report summarizes the method for measuring and evaluating of radioactivity concentration for concrete generated from modification activities of JRR-3.

Journal Articles

Analysis of Th, U, Pu, and Am in radioactive metal waste using extraction chromatography

Shimada, Asako; Haraga, Tomoko; Hoshi, Akiko; Kameo, Yutaka; Nakashima, Mikio; Takahashi, Kuniaki

Journal of Radioanalytical and Nuclear Chemistry, 286(3), p.765 - 770, 2010/12

 Times Cited Count:4 Percentile:65.16(Chemistry, Analytical)

JAEA Reports

Analysis of the radioactivity concentrations in asphalt- or cement-solidified products generated from research facilities

Hoshi, Akiko; Kameo, Yutaka; Katayama, Atsushi; Sakai, Akihiro; Tsuji, Tomoyuki; Nakashima, Mikio; Kihara, Shinji; Takahashi, Kuniaki

JAEA-Data/Code 2009-023, 84 Pages, 2010/03

JAEA-Data-Code-2009-023.pdf:12.81MB

In order to establish the practical evaluation methods such as scaling factor method to determine the radioactivity concentrations of the important nuclides for safety assessment of disposal of radioactive wastes, we analyzed low-level radioactive liquid waste (56 samples), which is generated from various research facilities at Nuclear Science Research Institute from FY1998 to FY2007 and accumulated the radioactivity concentrations data (563 data) of the 17 important nuclides. We investigated the correlation of the radioactivity concentrations of the important nuclides with the "Key nuclides ($$^{60}$$Co or $$^{137}$$Cs)". In present paper, the radioactivity concentrations data of the 17 important nuclides and the results of the correlation of the radioactivity concentrations are summarized for the data to establish the practical evaluation methods to determine the radioactivity concentrations in asphalt-solidified or cement-solidified products.

JAEA Reports

Clearance of concrete generated from modification activities of JRR-3; Investigation of contamination situation of concrete

Satoyama, Tomonori; Kishimoto, Katsumi; Takaizumi, Hirohide; Hoshi, Akiko; Okoshi, Minoru; Tachibana, Mitsuo

JAEA-Technology 2009-060, 42 Pages, 2010/01

JAEA-Technology-2009-060.pdf:4.17MB

In the modification activities of JRR-3, a large volume of extremely low-level radioactive concrete debris were generated from dismantling of concrete structure around reactor body during one-piece removal of reactor body. These concrete debris are stored in the waste storage facility NL of the Nuclear Science Research Institute. The applicability of clearance to concrete debris generated from the modification activities of JRR-3 was examined as waste measures in the Nuclear Science Research Institute. First, generated place, amount of volume and radioactivity of concrete debris in the waste storage facility NL were surveyed from records in the modification of JRR-3 and data sheets of radioactive waste stored in the waste storage facility. Next, the radioactivity of samples taken from concrete debris stored in the waste storage facility NL was measured, and distribution of those radioactivity concentration was investigated to evaluate the contamination situation. In addition, activated contamination situation of concrete structure was evaluated by activated calculation. As a result, radioactivity of concrete debris was enough lower than clearance levels, so it was found that concrete debris in the waste storage facility NL was able to treat as clearance materials.

Journal Articles

Simple determination of $$^{99}$$Tc in radioactive waste using Tc extraction disk and imaging plates

Kameo, Yutaka; Katayama, Atsushi; Hoshi, Akiko; Haraga, Tomoko; Nakashima, Mikio

Applied Radiation and Isotopes, 68(1), p.139 - 143, 2010/01

 Times Cited Count:8 Percentile:44.15(Chemistry, Inorganic & Nuclear)

A simple method was developed for determination of $$^{99}$$Tc in low-level radioactive waste: Technetium-99 retained by a solid phase extraction disk was directly measured with imaging plates system. It was found that more than 97% of Tc were retained by the disk from a solution of pH 2 to 12, whereas depth profile of Tc in the disk, which greatly influences the counting efficiency, depended on solution pH. The present method was successfully applied to actual radioactive liquid waste samples arising from nuclear research facilities.

JAEA Reports

Simple and rapid determination methods for low-level radioactive wastes generated from nuclear research facilities (Guidelines for determination of radioactive waste samples)

Kameo, Yutaka; Shimada, Asako; Ishimori, Kenichiro; Haraga, Tomoko; Katayama, Atsushi; Hoshi, Akiko; Nakashima, Mikio

JAEA-Technology 2009-051, 81 Pages, 2009/10

JAEA-Technology-2009-051.pdf:3.6MB

Simple and rapid determination methods were developed for an evaluation of important nuclides, U, and Th in wastes generated from research facilities at Nuclear Science Research Institute and Oarai Research and Development Center. The present methods were assumed to apply to solidified products made from miscellaneous wastes by plasma melting at the Advanced Volume Reduction Facilities. In order to reduce costs of radiochemical analysis and to establish a routine analytical system, counting efficiency of non-destructive $$gamma$$-ray measurements was improved, and times for pretreatment of solidified product samples and subsequent radiochemical separations were shortened. In addition to this, rapid and high sensitive detection methods were developed for a determination of long-lived nuclides. The present paper describes guidelines for the determination of radionuclides in the low-level radioactive wastes by using the present simple and rapid methods.

Journal Articles

Analytical method for $$^{59}$$Ni and $$^{63}$$Ni in low-level radioactive wastes arising from nuclear research facilities

Kameo, Yutaka; Haraga, Tomoko; Katayama, Atsushi; Hoshi, Akiko; Nakashima, Mikio

Radioisotopes, 58(5), p.153 - 160, 2009/05

A routine analytical method was developed for the determination of $$^{59}$$Ni and $$^{63}$$Ni in low-level radioactive wastes arising from nuclear research facilities. A separation scheme of $$^{59}$$Ni and $$^{63}$$Ni in waste samples was optimized by considering concentration of interference radionuclides and chemical composition of the waste samples. Concentrations of $$^{59}$$Ni and $$^{63}$$Ni in actual radioactive wastes such as pipes and liquid waste could be well determined by the present analytical method. In the determination, the time required for the chemical separation was five to seven days per ten samples. It was concluded that the present method could be applied to a routine determination of $$^{59}$$Ni and $$^{63}$$Ni in low-level radioactive wastes. In the present experiment, radioactivity ratio of $$^{63}$$Ni/$$^{59}$$Ni in pipe samples, which were taken from a nuclear research reactor, was estimated by a computer code (ORIGEN2). Radioactivity ratio of $$^{63}$$Ni/$$^{59}$$Ni, obtained by the computer calculation, was ranged from 98 to 109 and that obtained by the present analytical method was 118 $$pm$$ 6.

Journal Articles

Influence of hydrofluoric acid on extraction of thorium using a commercially available extraction chromatographic resin

Fujiwara, Asako; Hoshi, Akiko; Kameo, Yutaka; Nakashima, Mikio

Journal of Chromatography A, 1216(18), p.4125 - 4127, 2009/03

 Times Cited Count:8 Percentile:70.19(Biochemical Research Methods)

Dependence of Th recovery on HF concentration in nitric acid solutions (1$$sim$$5 mol/dm$$^{3}$$) containing 1$$times$$10$$^{-6}$$ mol/dm$$^{3}$$ of Th and various concentrations of HF was studied using a commercially available UTEVA resin column (for uranium and tetravalent actinide). Thorium recovery decreased with an increase in the HF concentration in the sample solutions. The concentration of HF at which Th recovery started to decrease was about 1$$times$$10$$^{-4}$$ mol/dm$$^{3}$$ in 1 mol/dm$$^{3}$$ HNO$$_{3}$$ solution, about 1$$times$$10$$^{-3}$$ mol/dm$$^{3}$$ in 3 mol/dm$$^{3}$$ HNO$$_{3}$$ solution, and about 1$$times$$10$$^{-2}$$ mol/dm$$^{3}$$ in 5 mol/dm$$^{3}$$ HNO$$_{3}$$ solution. When Al(NO$$_{3}$$)$$_{3}$$ (0.2 mol/dm$$^{3}$$) or Fe(NO$$_{3}$$)$$_{3}$$ (0.6 mol/dm$$^{3}$$) was added as a masking agent for F$$^{-}$$ into the Th solution containing 1$$times$$10$$^{-1}$$ mol/dm$$^{3}$$ HF and 1 mol/dm$$^{3}$$ HNO$$_{3}$$, the Th recovery improved from 1.4$$pm$$0.3% to 95$$pm$$5% or 93$$pm$$3%. Effective extraction of Th on UTEVA resin was achieved by selecting the concentration of HNO$$_{3}$$ and/or adding masking agents such as Al(NO$$_{3}$$)$$_{3}$$ according to the concentration of HF in the sample solution.

Journal Articles

Rapid separation of alpha-emitting nuclides in radioactive waste

Hoshi, Akiko; Watanabe, Koichi; Fujiwara, Asako; Haraga, Tomoko; Kameo, Yutaka; Nakashima, Mikio; Takebe, Shinichi

Nippon Genshiryoku Gakkai Wabun Rombunshi, 7(3), p.177 - 185, 2008/09

The simple and rapid separation method was developed for actinides in the low-level radioactive waste. Extraction chromatographic columns were used for the separation of U, Np, Pu, Am, and Cm in the solution of the simulated solidified product and the simulated waste solution. In the investigation of separation procedure, it was tried to construct the scheme with the relatively non-corrosive reagents aiming to apply to the routine analysis of the radioactive waste. Recoveries and decontamination factors of actinides in the solution of simulated waste were high enough to determine of actinides in radioactive waste by alpha-spectrometry, mass spectroscopy. The time required of the separation operation was 2-3 hours. The chromatographic method was applied to analysis of actinide in actual waste solution, high recoveries and decontamination factors were obtained, which indicated that the extraction chromatographic separation method would be adopted as a simple and rapid separation method of actinide in waste.

JAEA Reports

Research and development on the melting test of low-level radioactive miscellaneous solid waste

Nakashio, Nobuyuki; Kameo, Yutaka; Hoshi, Akiko; Nakashima, Mikio

JAEA-Review 2007-005, 35 Pages, 2007/02

JAEA-Review-2007-005.pdf:2.28MB

The Nuclear Science Research Institute of the Japan Atomic Energy Agency constructed the Advanced Volume Reduction Facilities (AVRF) in February 2003 for treatment of low-level radioactive miscellaneous solid waste (LLW). The waste volume reduction is carried out by a high-compaction process or melting processes in the AVRF. In advance of operating the melting process in the AVRF, melting tests of simulated LLW with RI tracers ($$^{60}$$Co, $$^{137}$$Cs and $$^{152}$$Eu) have been conducted by using the plasma melter in pilot scale. Viscosity of molten waste, chemical composition and physical properties of solidified products and distribution of the tracers in each product were investigated in various melting conditions. In this review, experimental results of the melting tests were discussed in order to contribute to actual treatment of LLW in the AVRF.

Journal Articles

Application of extraction chromatography to the separation of thorium and uranium dissolved in a solution of high salt concentration

Fujiwara, Asako; Kameo, Yutaka; Hoshi, Akiko; Haraga, Tomoko; Nakashima, Mikio

Journal of Chromatography A, 1140(1-2), p.163 - 167, 2007/01

 Times Cited Count:20 Percentile:44.68(Biochemical Research Methods)

Extraction chromatography with UTEVA resin was applied to separation of Th and U from control solutions prepared from a multi-element control solution and from sample solutions of solidified simulated waste. Thorium and U in control solutions with 1 to 5 M HNO$$_{3}$$ were extracted with UTEVA resin and recovered with a solution containing 0.1 M HNO$$_{3}$$ and 0.05 M oxalic acid to be separated from the other metallic elements. Extraction behavior of U in the sample solutions was similar to that in the control solutions, but extraction of Th was dependent on the concentration of HNO$$_{3}$$. Thorium was extracted from 5 M HNO$$_{3}$$ sample solutions but not from 1 M HNO$$_{3}$$ sample solutions. We conjecture that thorium fluoride formation interferes with extraction of Th. Addition of Al(NO$$_{3}$$)$$_{3}$$ and Fe(NO$$_{3}$$)$$_{3}$$, which have a higher stability constant with fluoride ion than Th does with it improved extractability of Th from 1 M HNO$$_{3}$$ sample solution.

JAEA Reports

Study on coincidence and anti-coincidence $$gamma$$-ray spectrometry for the rapid radioactivity evaluation of solidified products prepared from radioactive wastes

Haraga, Tomoko; Kameo, Yutaka; Hoshi, Akiko; Yonezawa, Chushiro*; Nakashima, Mikio

JAERI-Tech 2005-050, 35 Pages, 2005/09

JAERI-Tech-2005-050.pdf:1.35MB

Non-destructive $$gamma$$-ray spectrometry has been examined as a simple and rapid radioactivity measurement technique for the solidified products prepared by plasma melting for low level radioactive miscellaneous wastes generated from nuclear facilities. The Compton background resulting from the coexisting radionuclides pose a problem in the usual $$gamma$$-ray spectrometry which uses only a Ge detector. In order to reduce the background count and to measure the interested nuclide selectively, the coincidence and the anti-coincidence $$gamma$$-ray spectrometry using the Ge-BGO detector system were examined. As a result of applying the anti-coincidence $$gamma$$-ray spectrometry to a single $$gamma$$-ray emitter $$^{137}$$Cs and the coincidence $$gamma$$-ray spectrometry to multiple $$gamma$$-ray emitter $$^{152}$$Eu under existence of $$^{60}$$Co, the detection limits of $$^{137}$$Cs and $$^{152}$$Eu in the sample, which contained $$^{60}$$Co, were reduced by a factor of about 6 and 1.5, respectively. It was confirmed that the present methods are useful for the $$gamma$$-activity measurement of solidified products.

Journal Articles

Chemical stability of solidified products made from incombustible wastes by plasma melting

Kameo, Yutaka; Haraga, Tomoko; Nakashio, Nobuyuki; Hoshi, Akiko; Nakashima, Mikio

Nippon Genshiryoku Gakkai Wabun Rombunshi, 3(4), p.354 - 362, 2004/12

In order to investigate chemical stability of solidified products made from Low Level Radioactive Wastes (LLW) by plasma melting, a leaching test based on the MCC (Material Characterization Center)-3S Agitated Powder Leach Test Method was performed to determine Normalized Elemental Mass Loss (NL$$_{i}$$) of both main components (Na, Al, Si, Ca, and Fe) of the solidified product and radioactive tracers ($$^{60}$$Co, $$^{137}$$Cs, and $$^{152}$$Eu) incorporated into it. The results of leaching test indicated that NLi value was greatly affected by basicity defined as weight ratio of CaO to SiO$$_{2}$$ in the solidified product, while effect of FeO concentration on NL$$_{i}$$ value was small. In the case of basicity less than 0.8, logarithm of NL$$_{i}$$ linearly increased with the basicity, implying that NL$$_{i}$$ value can be estimated by chemical composition of the solidified products.

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