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JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR, JRR-3 and JRR-4 Facilities

Tsuchida, Daiki; Mitsukai, Akina; Aono, Ryuji; Haraga, Tomoko; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2022-004, 87 Pages, 2022/07

JAEA-Data-Code-2022-004.pdf:6.73MB

Radioactive wastes generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried in the near surface disposal field. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes until by the beginning of disposal. In order to contribute to this work, we collected and analyzed samples generated from JPDR, JRR-3 and JRR-4. In this report, radioactivity concentrations of 20 radionuclides ($$^{3}$$H, $$^{14}$$C, $$^{36}$$Cl, $$^{60}$$Co, $$^{63}$$Ni, $$^{90}$$Sr, $$^{94}$$Nb, $$^{99}$$Tc, $$^{rm 108m}$$Ag, $$^{129}$$I, $$^{137}$$Cs, $$^{152}$$Eu, $$^{154}$$Eu, $$^{234}$$U, $$^{238}$$U, $$^{238}$$Pu, $$^{239+240}$$Pu, $$^{241}$$Am, $$^{244}$$Cm) were determined based on radiochemical analysis and summarized as basic data for the study of evaluation method of radioactive concentration.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JPDR and JRR-4

Aono, Ryuji; Mitsukai, Akina; Haraga, Tomoko; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2020-006, 70 Pages, 2020/08

JAEA-Data-Code-2020-006.pdf:2.59MB

Radioactive wastes which generated from research and testing reactors in Japan Atomic Energy Agency are planning to be buried at the near surface disposal field. Therefore, it is required to establish the method to evaluate the radioactivity concentrations of radioactive wastes by the time it starts disposal. In order to contribute to this work, we collected and analyzed the samples generated from JPDR and JRR-4. In this report, we summarized the radioactivity concentrations of 19 radionuclides ($$^{3}$$H, $$^{14}$$C, $$^{36}$$Cl, $$^{60}$$Co, $$^{63}$$Ni, $$^{90}$$Sr, $$^{94}$$Nb, $$^{99}$$Tc, $$^{rm 108m}$$Ag, $$^{129}$$I, $$^{137}$$Cs, $$^{152}$$Eu, $$^{154}$$Eu, $$^{234}$$U, $$^{238}$$U, $$^{238}$$Pu, $$^{239+240}$$Pu, $$^{241}$$Am, $$^{244}$$Cm) which were obtained from radiochemical analysis of those samples.

Journal Articles

Neutronics assessment of advanced shield materials using metal hydride and borohydride for fusion reactors

Hayashi, Takao; Tobita, Kenji; Nishio, Satoshi; Ikeda, Kazuki*; Nakamori, Yuko*; Orimo, Shinichi*; DEMO Plant Design Team

Fusion Engineering and Design, 81(8-14), p.1285 - 1290, 2006/02

 Times Cited Count:20 Percentile:80.39(Nuclear Science & Technology)

Neutron transport calculations were carried out to evaluate the capability of metal hydrides and borohydrides as an advanced shielding material. Some hydrides indicated considerably higher hydrogen content than polyethylene and solid hydrogen. The hydrogen-rich hydrides show superior neutron shielding capability to the conventional materials. From the temperature dependence of dissociation pressure, ZrH$$_{2}$$ and TiH$$_{2}$$ can be used without releasing hydrogen at the temperature of less than 640 $$^{circ}$$C at 1 atm. ZrH$$_{2}$$ and Mg(BH$$_{4}$$)$$_{2}$$ can reduce the thickness of the shield by 30% and 20% compared to a combination of steel and water, respectively. Mixing some hydrides with F82H produces considerable effects in $$gamma$$-ray shielding. The neutron and $$gamma$$-ray shielding capabilities decrease in order of ZrH$$_{2}$$ $$>$$ Mg(BH$$_{4}$$)$$_{2}$$ and F82H $$>$$ TiH$$_{2}$$ and F82H $$>$$ water and F82H.

Journal Articles

Numerical analysis of fractional distillation characteristics for radioactive metallic waste vaporized in the shape of atomic beam

Akaoka, Katsuaki; Maruyama, Yoichiro

Nihon Genshiryoku Gakkai Wabun Rombunshi, 4(2), p.127 - 134, 2005/06

The fractional distillation characteristics of the materials used for the reactor pressure vessel made of ASTM A302B and the structures in reactor made of SUS304 which are the radioactive metallic waste of Japan Power Demonstration Reactor (JPDR) were analyzed numerically. In the simulation, the vaporization rates of the components of the waste were calculated by using the Langmuir's equation and Henry's law. As the result of simulation, it was calculated that $$^{152}$$Eu, $$^{154}$$Eu, $$^{14}$$C and $$^{94}$$Nb can be reduced to less than clearance level by the fractional distillation. On the ASTM A302B case, it was pointed out that the other radioactive nuclei which are $$^{54}$$Mn, $$^{55}$$Fe, $$^{60}$$Co, $$^{59}$$Ni and $$^{63}$$Ni satisfy clearance level after 77 years cooling down. On the SUS304 case, it was pointed out that $$^{59}$$Ni and $$^{63}$$Ni must be separated to satisfy clearance level using isotope separation.

Journal Articles

Numerical analysis of fractional distillation for radioactive metal

Akaoka, Katsuaki; Maruyama, Yoichiro

RIST News, (39), p.23 - 31, 2005/03

For the separation of radionuclide from the radioactive metallic waste generated by the decommissioning of nuclear facilities, a new method combined with the distillation and laser separation is being studied. The characteristics of fractional distillation for duralumin were analyzed numerically using the Henry's law and the Langmuir's equation, and its result agreed well with the experiment. Next, the fractional distillation characteristics of the materials used for the structures in reactor made of SUS304 which are the radioactive metallic waste of Japan Power Demonstration Reactor (JPDR) were analyzed numerically. As the result of the simulation, it was calculated that the radioactive metallic waste will be reduced to less than 1/100.

Journal Articles

New laser decontamination technique for radioactively contaminated metal surfaces using acid-bearing sodium silicate gel

Kameo, Yutaka; Nakashima, Mikio; Hirabayashi, Takakuni*

Journal of Nuclear Science and Technology, 41(9), p.919 - 924, 2004/09

 Times Cited Count:10 Percentile:57.33(Nuclear Science & Technology)

A new laser decontamination method utilizing a gel made from a sodium silicate solution and an acid was developed for removing radioactive nuclide incorporated into a surface oxide layer on metal waste. Decontamination tests were carried out using both simulated contaminated samples and pipe specimens cut from the primary coolant system of the Japan Power Demonstration Reactor. In the case of surface oxide layer consisting mainly of iron oxide, more than 99% of surface radioactivities were removed after two to three decontamination runs. In order to ascertain the role of laser irradiation on chemical reactions, chemical states of O and Fe in the oxide layer before and after decontamination were analyzed by X-ray photoelectron spectroscopy. It was found that the oxide layer was dissolved into the acid-containing gel, and the reaction was extensively promoted by the laser irradiation.

JAEA Reports

Numerical analysis of fractional distillation characteristics for radioactive metallic waste

Akaoka, Katsuaki; Maruyama, Yoichiro

JAERI-Research 2004-012, 12 Pages, 2004/08

JAERI-Research-2004-012.pdf:3.52MB

The fractional distillation characteristics at between 0 $$^{circ}$$C and 2500 $$^{circ}$$C(the rate is 200 $$^{circ}$$C/h) of radioactive metallic waste for JPDR which mainly consists of stainless steel were analyzed numerically. In the simulation, the vaporization rates of the components of JPDR waste were calculated by using the Langmuir's equation and Henry's law. As the results, it was calculated that $$^{152,154}$$Eu, $$^{14}$$C and $$^{94}$$Nb can be removed by the fractional distillation. On the other hand, $$^{54}$$Mn and $$^{55}$$Fe can be reduced by cooling them for about 30 years. Therefore, by removing $$^{59,63}$$Ni and $$^{60}$$Co using laser separation method, it will be possible to reduce the radioactive metallic waste by less than one one-hundredth.

Journal Articles

High-sensitive detection by direct interrogation of 14 MeV Acc neutrons, 1; Uranium-contained metal matrix in a waste dram

Haruyama, Mitsuo; Takase, Misao*; Tobita, Hiroshi; Mori, Takamasa

Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(2), p.185 - 192, 2004/06

no abstracts in English

Journal Articles

An Investigation of steel plate-cast iron hybrid casting process for recycling of low level radioactive metal waste

Nakamura, Hisashi; Hirabayashi, Takakuni; Akimoto, Jun*; Takahashi, Kenji*; Shindo, Hideaki; Sakurai, Daihachiro*; Almansour, A.*; Okane, Toshimitsu*; Umeda, Takateru*

Materials Science Forum, 329-330, p.441 - 448, 2000/00

no abstracts in English

Journal Articles

Restricted recycling technology development for radioactive metallic waste; Waste container fablication tests

Nakamura, Hisashi; Hirabayashi, Takakuni

Nihon Kikai Gakkai Dai-6-Kai Doryoku, Enerugi Gijutsu Shimpojiumu '98 Koen Rombunshu, p.371 - 376, 1998/00

no abstracts in English

Journal Articles

Analysis and prediction of geochemical dynamic processes near the earths surface

Kobutsugaku Zasshi, 19(5), p.289 - 293, 1990/07

no abstracts in English

11 (Records 1-11 displayed on this page)
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