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JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JRR-2, JRR-3 and hot laboratory facilities

Tobita, Minoru*; Haraga, Tomoko; Sasaki, Takayuki*; Seki, Kotaro*; Omori, Hiroyuki*; Kochiyama, Mami; Shimomura, Yusuke; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2019-016, 72 Pages, 2020/02

JAEA-Data-Code-2019-016.pdf:2.67MB

In the future, radioactive wastes which generated from research and testing reactors in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. 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 JRR-2, JRR-3 and Hot laboratory facilities. In this report, we summarized the radioactivity concentrations of 25 radionuclides ($$^{3}$$H, $$^{14}$$C, $$^{36}$$Cl, $$^{60}$$Co, $$^{63}$$Ni, $$^{90}$$Sr, $$^{94}$$Nb, $$^{93}$$Mo, $$^{99}$$Tc, $$^{108m}$$Ag, $$^{126}$$Sn, $$^{129}$$I, $$^{137}$$Cs, $$^{152}$$Eu, $$^{154}$$Eu, $$^{233}$$U, $$^{234}$$U, $$^{238}$$U, $$^{238}$$Pu, $$^{239}$$Pu, $$^{240}$$Pu, $$^{241}$$Pu, $$^{241}$$Am, $$^{243}$$Am, $$^{244}$$Cm) which were obtained from radiochemical analysis of those samples.

JAEA Reports

Waste liquid treatment for uranium liquid waste containing impurities

Sato, Yoshiyuki; Aono, Ryuji; Haraga, Tomoko; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Testing 2019-003, 20 Pages, 2019/12

JAEA-Testing-2019-003.pdf:2.08MB

In the Radioactive Waste Management Technology Section, the radioactive liquid waste generated in the test using natural uranium in the past has been stored based on the contents of permission. Although we decided to perform solidification treatment in order to reduce the risk in storage, no rational treatment method has been established so far. Therefore, we examined adsorption treatment of natural uranium using uranium adsorbent (Tannix), and finally stabilized treatment by cement solidification. The treatment methods and findings obtained for a series of operations in waste liquid treatment are summarized in this report for reference when treating similar liquid waste.

Journal Articles

Positronium in room temperature ionic liquids

Hirade, Tetsuya

AIP Conference Proceedings 2182, p.030007_1 - 030007_5, 2019/12

There are many new application of room temperature ionic liquids (RTILs) for many different fields. One of them is reprocessing spent nuclear fuels and then research of irradiation effects on RTILs are very important. The positron annihilation techniques are very strong tool to investigate fast reactions of excess electrons. Positron annihilation age-momentum correlation (AMOC) experiment was applied to deepen understanding the phenomena occurred at very young positron ages. We clarified that Ps bubble formation in RTILs was very slow and, finally, oscillation of Ps bubble was observed just after the Ps formation at near melting temperatures. These results can indicate that Ps formation occurred in very short time in RTILs. The phenomena observed by Ps just in RTILs will be discussed.

Journal Articles

On the hydrogen production of geopolymer wasteforms under irradiation

Cantarel, V.; Arisaka, Makoto; Yamagishi, Isao

Journal of the American Ceramic Society, 102(12), p.7553 - 7563, 2019/12

 Times Cited Count:0 Percentile:100(Materials Science, Ceramics)

The hydrogen gas (H$$_{2}$$) production of wasteforms is a major safety concern for encapsulating nuclear wastes. For geopolymers, the H$$_{2}$$ produced by radiolytic processes is a key factor because of the large amount of water present in their porous structure. Herein, the hydrogen production was measured under $$^{60}$$Co gamma irradiation. The effect of water saturation and sample size were studied for pure geopolymers, or using zeolites as an example waste. When geopolymer monolithic samples were large and saturated by water, the hydrogen released was measured up to two orders of magnitude lower with a 40 cm long cylinder samples (1.9$$times$$10$$^{-10}$$ mol/J) than a sample in powder form (2.2$$times$$10$$^{-8}$$ mol/J). To interpret results, a simple model was used, considering only hydrogen production, a potential recombination and its diffusion in the geopolymer matrix. Knowing the diffusion constant of the matrix, the model was able to reproduce the evolution of the hydrogen release as a function of the water saturation level and predict the evolution when sample size is increased up to 40 cm.

JAEA Reports

Study on the evaluation methodology of the radioactivity concentration in low-level radioactive wastes generated from post irradiation examination facility

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

JAEA-Technology 2019-015, 52 Pages, 2019/11

JAEA-Technology-2019-015.pdf:2.46MB

In the future, radioactive waste which generated from nuclear research facilities in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. It is necessary to establish the method to evaluate the radioactivity concentrations of the radioactive wastes. In this work, we studied the evaluation method of radioactivity concentration based on radiochemical analysis data (H-3, C-14, Cl-36, Co-60, Ni-63, Sr-90, Mo-93, Nb-94, Tc-99, Ag-108m, Sn-126, I-129, Cs-137, Eu-152, Eu-154, U-233+234, U-238, Pu-238, Pu-239+240, Pu-241, Am-241, Am-243, Cm-244) which was generated from research facility Hot Laboratory. As a result of examining the application of the scaling factor method, the correlation with Key-nuclide in some nuclides which are Sr-90, I-129, Eu-154, U-233+234, Pu-238, Pu-239+240, Am-241, Cm-244 confirmed by the correlation coefficient and t-test. In the present radiochemical analysis data, the mean activity concentration method can be applied to all nuclides which could not be applied to the scaling factor method H-3, C-14, Cl-36, Ni-63, Mo-93, Nb-94, Tc-99, Ag-108m, Sn-126, Eu-152, U-238, Pu-241 and Am-243. Ni-63, Tc-99, Eu-152 and U-238 could be applied to the scaling factor method with getting several additional data, this study will be continued to review for the practical evaluation method.

JAEA Reports

Analysis of the radioactivity concentrations in low-level radioactive waste generated from JRR-2 and JRR-3 facilities

Haraga, Tomoko; Shimomura, Yusuke; Mitsukai, Akina; Ishimori, Kenichiro; Kameo, Yutaka

JAEA-Data/Code 2019-004, 48 Pages, 2019/10

JAEA-Data-Code-2019-004.pdf:4.67MB

In the future, radioactive wastes which generated from research and testing reactors in Japan Atomic Energy Agency are planning to be buried for the near surface disposal. 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 JRR-2 and JRR-3. 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

Rapid analytical method of $$^{90}$$Sr in urine sample; Rapid separation of Sr by phosphate co-precipitation and extraction chromatography, followed by determination by triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS)

Tomita, Jumpei; Takeuchi, Erina

Applied Radiation and Isotopes, 150, p.103 - 109, 2019/08

 Times Cited Count:1 Percentile:100(Chemistry, Inorganic & Nuclear)

A rapid analytical method for determining $$^{90}$$Sr in urine samples (1-2 L) was developed to assess the internal exposure of workers in a radiological emergency. Strontium in a urine sample was rapidly separated by phosphate co-precipitation, followed by extraction chromatography with a tandem column of Pre-filter, TRU and Sr resin, and the $$^{90}$$Sr activity was determined by ICP-MS/MS. Measurement in the MS/MS mode with an O$$_{2}$$ reaction gas flow rate 1 mL min$$^{-1}$$ showed no tailing of $$^{88}$$Sr at m/z = 90 up to 50 mg-Sr L$$^{-1}$$. The interferences of Ge, Se and Zr at m/z = 90 were successfully removed by chemical separation. This analytical method was validated by the results of the analyses of synthetic urine samples (1.2-1.6 L) containing a known amount of $$^{90}$$Sr along with 1 mg of each of Ge, Se, Sr and Zr. The turnaround time for analysis was about 10 h, and the detection limit of $$^{90}$$Sr was approximately 1 Bq per urine sample.

Journal Articles

Novel universality class for the ferromagnetic transition in the low carrier concentration systems UTeS and USeS exhibiting large negative magnetoresistance

Tateiwa, Naoyuki; Haga, Yoshinori; Sakai, Hironori; Yamamoto, Etsuji

Physical Review B, 100(6), p.064413_1 - 064413_7, 2019/08

 Times Cited Count:0 Percentile:100(Materials Science, Multidisciplinary)

We report the novel critical behavior of magnetization in low carrier concentration systems UTeS and USeS that exhibit the large negative magnetoresistance around the ferromagnetic transition temperatures $$T_{rm C}$$ $$sim$$ 85 and 23 K, respectively. We determine the critical exponents, $$beta$$ for the spontaneous magnetization $$M_{rm s}$$, $$gamma$$ for the magnetic susceptibility $$chi$$, and $$delta$$ for the magnetization isotherm at $$T_{rm C}$$ with several analytical methods. The ferromagnetic states in UTeS and USeS have strong uniaxial magnetic anisotropy. However, the critical exponents in the two compounds are different from those in the three-dimensional Ising system. Similar exponents have been reported for the uranium ferromagnetic superconductors UGe$$_2$$ and URhGe. An important finding is that the novel critical phenomenon appears regardless of the charge carrier density or the degree of the itinerancy of the $$5f$$ electrons.

Journal Articles

$$^{125}$$Te-NMR study on a single crystal of heavy fermion superconductor UTe$$_2$$

Tokunaga, Yo; Sakai, Hironori; Kambe, Shinsaku; Hattori, Taisuke; Higa, Nonoka; Nakamine, Genki*; Kitagawa, Shunsaku*; Ishida, Kenji*; Nakamura, Ai*; Shimizu, Yusei*; et al.

Journal of the Physical Society of Japan, 88(7), p.073701_1 - 073701_4, 2019/07

 Times Cited Count:5 Percentile:4.38(Physics, Multidisciplinary)

We report $$^{125}$$Te-NMR studies on a newly discovered heavy fermion superconductor UTe$$_2$$. Using a single crystal, we have measured the $$^{125}$$Te-NMR Knight shift $$K$$ and spin-lattice relaxation rate $$1/T_1$$ for fields along the three orthorhombic crystal axes. The data confirm a moderate Ising anisotropy for both the static ($$K$$) and dynamical susceptibilities ($$1/T_1$$) in the paramagnetic state above about 20 K. Around 20 K, however, we have observed a sudden loss of NMR spin-echo signal due to sudden enhancement of the NMR spin-spin relaxation rate $$1/T_2$$, when the field is applied along the easy axis of magnetization (=$$a$$ axis). This behavior suggests the development of longitudinal magnetic fluctuations along the $$a$$ axis at very low frequencies below 20 K.

Journal Articles

Anomalous ferromagnetic ordering in EuCuP

Iha, Wataru*; Kakihana, Masashi*; Matsuda, Shinya*; Honda, Fuminori*; Haga, Yoshinori; Takeuchi, Tetsuya*; Nakashima, Miho*; Amako, Yasushi*; Gochi, Jun*; Uwatoko, Yoshiya*; et al.

Journal of Alloys and Compounds, 788, p.361 - 366, 2019/06

 Times Cited Count:0 Percentile:100(Chemistry, Physical)

Journal Articles

Measurements of thermal-neutron capture cross-section and resonance integral of neptunium-237

Nakamura, Shoji; Kitatani, Fumito; Kimura, Atsushi; Uehara, Akihiro*; Fujii, Toshiyuki*

Journal of Nuclear Science and Technology, 56(6), p.493 - 502, 2019/06

 Times Cited Count:1 Percentile:22.81(Nuclear Science & Technology)

The thermal-neutron capture cross-section($$sigma_{0}$$)and resonance integral(I$$_{0}$$) were measured for the $$^{237}$$Np(n,$$gamma$$)$$^{238}$$Np reaction by an activation method. A method with a Gadolinium filter, which is similar to the Cadmium difference method, was used to measure the $$sigma_{0}$$ with paying attention to the first resonance at 0.489 eV of $$^{237}$$Np, and a value of 0.133 eV was taken as a cut-off energy. Neptunium-237 samples were irradiated at the pneumatic tube of the Kyoto University Research Reactor in Institute for Integral Radiation and Nuclear Science, Kyoto University. Wires of Co/Al and Au/Al alloys were used as monitors to determine thermal-neutron fluxes and epi-thermal Westcott's indices at an irradiation position. A $$gamma$$-ray spectroscopy was used to measure activities of $$^{237}$$Np, $$^{238}$$Np and neutron monitors. On the basis of Westcott's convention, the $$sigma_{0}$$ and I$$_{0}$$ values were derived as 186.9$$pm$$6.2 barn, and 1009$$pm$$90 barn, respectively.

Journal Articles

Evidence for weak spin-orbit interaction experienced by Cooper pairs in the spin-triplet superconductor UPt$$_3$$; $$^{195}$$Pt-NMR study

Aoyama, Taisuke*; Kotegawa, Hisashi*; Kimura, Noriaki*; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika*; To, Hideki*

Journal of the Physical Society of Japan, 88(6), p.064706_1 - 064706_7, 2019/06

 Times Cited Count:0 Percentile:100(Physics, Multidisciplinary)

Journal Articles

Flow-electrode CDI removes the uncharged Ca-UO$$_{2}$$-CO$$_{3}$$ ternary complex from brackish potable groundwater; Complex dissociation, transport, and sorption

Ma, J.*; Zhang, Y.*; Collins, R. N.*; Tsarev, S.*; Aoyagi, Noboru; Kinsela, A. S.*; Jones, A. M.*; Waite, T. D.*

Environmental Science & Technology, 53(5), p.2739 - 2747, 2019/03

 Times Cited Count:3 Percentile:37.68(Engineering, Environmental)

Journal Articles

Structure of nitride layer formed on titanium alloy surface by N$$_{2}$$-gas exposure at high temperatures

Takeda, Yusuke; Iida, Kiyoshi*; Sato, Shinji*; Matsuo, Tadatoshi*; Nagashima, Yasuyuki*; Okubo, Nariaki; Kondo, Keietsu; Hirade, Tetsuya

JPS Conference Proceedings (Internet), 25, p.011023_1 - 011023_3, 2019/03

In this study, we prepared samples under two different conditions, (1) 810$$^{circ}$$C, for 600 min, and (2) 850$$^{circ}$$C, for 720 min. A depth-profile analysis of the surfaces of the samples is conducted through Doppler broadening (DB) measurements of positron annihilation $$gamma$$ rays using a slow positron beam. It was indicated that many of positrons annihilated in defects near the surface. According to the TEM image, there are nano-crystal grains near the surface and then positrons can diffuse in the grains and annihilate in defects at the grain boundaries. Furthermore, DB measurements indicated that there is a depth dependence on the chemical composition where positrons annihilate. EDS spectroscopy measurements also indicated that there is a depth dependence of impurities such as Vanadium. These results indicated change of the chemical composition at the grain boundaries.

Journal Articles

Quantum beats on triplet-positronium reactions in water

Hirade, Tetsuya

JPS Conference Proceedings (Internet), 25, p.011021_1 - 011021_2, 2019/03

Irradiation of water produce some reactive species such as OH radical. OH is formed by the reaction of a water cation and a water molecule just after ionization. On the other hand, a high energy positron injected in water will form cations and excess electrons even at the end part of the track. And hence, some positrons can form Positronium (Ps) with one of the excess electrons. The electrons in OH and Ps used to be in a same orbital in a water molecule before ionization of that water molecule. Therefore they were singlet at the time of the ionization. Every electron have each own hyperfine coupling constant after ionization. In water, reaction between Ps and OH, such as radical reaction or spin conversion, is possible. Therefore, quantum beats on these reaction can occur and the frequency of quantum beats will indicate the hyperfine coupling constant of OH which depends on the structure around OH. Therefore it is becoming possible to discuss the structure of water and reactivity of OH in the structure.

Journal Articles

Reaction between spin-correlated triplet positronium and OH radical in water

Hirade, Tetsuya

JPS Conference Proceedings (Internet), 25, p.011022_1 - 011022_3, 2019/03

OH radicals which are very reactive are formed by radiation decomposition in water. The behavior of OH radicals is important in corrosion of materials and reactions in living bodies. Recently, the reaction occurring between positronium (Ps) formed by OH radicals formed at the end of the positron track when positron is incident and positronium (Ps) formed by reaction of excess electrons formed with OH radical formation with the thermo-positron, it is reported that quantum beat occurs due to spin correlation. This quantum beat seems to have a period depending on the hyperfine coupling constant of OH radical. It is thought that the period and intensity of the quantum beat depends on the temperature, and it seems that it reflects the state around the OH radical. From the temperature dependence of the quantum beat detected by the reaction of this spin-correlated OH radical and triplet positronium we will explain what the liquid structure might be.

Journal Articles

Electronic structure in heavy fermion compound UPd$$_2$$Al$$_3$$ through directional Compton profile measurement

Koizumi, Akihisa*; Kubo, Yasunori*; Yamamoto, Etsuji; Haga, Yoshinori; Sakurai, Yoshiharu*

Journal of the Physical Society of Japan, 88(3), p.034714_1 - 034714_6, 2019/03

 Times Cited Count:0 Percentile:100(Physics, Multidisciplinary)

Journal Articles

Novel critical behavior of magnetization in URhSi; Similarities to the uranium ferromagnetic superconductors UGe$$_2$$ and URhGe

Tateiwa, Naoyuki; Haga, Yoshinori; Yamamoto, Etsuji

Physical Review B, 99(9), p.094417_1 - 094417_12, 2019/03

 Times Cited Count:3 Percentile:11.04(Materials Science, Multidisciplinary)

We study the critical behavior of dc magnetization in the uranium ferromagnet URhSi around the ferromagnetic phase transition at $$T_{rm C}{,}{sim}{,}$$10 K. The critical exponent $$beta$$ for the spontaneous magnetization below $$T_{rm C}$$, $$gamma$$ for the magnetic susceptibility, and $$delta$$ for the magnetic isotherm at $$T_{rm C}$$ have been determined as $$beta$$ = 0.300 $$pm$$ 0.002, $$gamma$$ = 1.00 $$pm$$ 0.02, and $$delta$$ = 4.32 $$pm$$ 0.04 by the scaling analysis and the critical isotherm analysis. Magnetization has strong uniaxial magnetic anisotropy in the ferromagnetic state of URhSi. However, the universality class of the critical phenomenon does not belong to the 3D Ising system ($$beta$$ = 0.325, $$gamma$$ = 1.241, and $$delta$$ = 4.82). The obtained exponents in URhSi are similar to those in uranium ferromagnetic superconductors UGe$$_2$$ and URhGe. We discuss the static and dynamical magnetic properties of URhSi in comparison with those in UGe$$_2$$, URhGe and UCoGe.

Journal Articles

Hydrogen gas measurements of phosphate cement irradiated during heat treatment

Irisawa, Keita; Kudo, Isamu*; Taniguchi, Takumi; Namiki, Masahiro*; Osugi, Takeshi; Nakazawa, Osamu

QST-M-16; QST Takasaki Annual Report 2017, P. 63, 2019/03

no abstracts in English

Journal Articles

Micro-PIXE analysis study of ferrite products synthesized from simulated radioactive liquid waste containing chemical hazardous elements

Abe, Tomohisa; Shimazaki, Takejiro; Osugi, Takeshi; Nakazawa, Osamu; Yamada, Naoto*; Yuri, Yosuke*; Sato, Takahiro*

QST-M-16; QST Takasaki Annual Report 2017, P. 140, 2019/03

no abstracts in English

1422 (Records 1-20 displayed on this page)