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JAEA Reports

Review and evaluation on the surface area of vitrified products of high-level waste; Surface area increase factors due to fracturing and their bases for the performance assessment of geological disposal

Igarashi, Hiroshi

JAEA-Review 2020-006, 261 Pages, 2020/09

JAEA-Review-2020-006.pdf:4.42MB

A literature review was conducted on the increase in surface area of vitrified products of HLW due to the fracturing caused by cooling during glass pouring process and by mechanical impact, from the perspective of a parameter of the radionuclide release model in the performance assessment of geological disposal system studied overseas. The review was focused on the value of surface area increase factor set as a parameter in the model, the experimental work to evaluate an increase in surface area, and how the parameters on surface area were determined based on the experimental results. The surface area obtained from the experiments executed in Japan was also discussed in comparison with the overseas studies. On the basis of the investigation, the effects of various conditions on the surface area were studied, such as a diameter of vitrified product, cooling condition during and after the glass pouring, impact on vitrified products during their handling, environment after the closure of disposal facility, and others. The causes of fracturing are associated with the phenomena or events in the waste management process such as production, transport, storage, and disposal. The surface area increase factors set in the nuclide release model of the glass and their bases were reviewed. In addition, the measured values and the experimental methods for surface increase factors published so far were compared. Accordingly, the methods for measuring surface area as the bases were identified for these factors set in the models. The causes of fracturing and features of these factors were studied with respect to the relation with the waste management process. The results from the review and assessment can contribute to the expanding the knowledge for the conservative and realistic application of these factors to performance assessment, and to the developing and upgrading of safety case as a consequence.

Journal Articles

In-source laser spectroscopy of dysprosium isotopes at the ISOLDE-RILIS

Chrysalidis, K.*; Barzakh, A. E.*; Ahmed, R.*; Andreyev, A. N.; Ballof, J.*; Cubiss, J. G.*; Fedorov, D. V.*; Fedosseev, V. N.*; Fraile, L. M.*; Harding, R. D.*; et al.

Nuclear Instruments and Methods in Physics Research B, 463, p.472 - 475, 2020/01

 Times Cited Count:2 Percentile:62.87(Instruments & Instrumentation)

A number of radiogenically produced dysprosium isotopes have been studied by in-source laser spectroscopy at ISOLDE using the Resonance Ionization Laser Ion Source (RILIS). Isotope shifts were measured relative to $$^{152}$$Dy in the $$4f^{10}6s^{2}~^{5}I_{8}$$ (gs) $$rightarrow$$ $$4f^{10}6s6p~(8,1)^{0}_{8}$$ (418.8 nm $$_{rm VAC}$$)resonance transition. The electronic factor, $$F$$, and mass shift factor, M, were extracted and used for determining the changes in mean-squared charge radii for $$^{rm 145m}$$Dy and $$^{rm 147m}$$Dy for the first time.

Journal Articles

$$alpha$$-decay branching ratio of $$^{180}$$Pt

Cubiss, J. G.*; Harding, R. D.*; Andreyev, A. N.; Althubiti, N.*; Andel, B.*; Antalic, S.*; Barzakh, A. E.*; Cocolios, T. E.*; Day Goodacre, T.*; Farooq-Smith, G. J.*; et al.

Physical Review C, 101(1), p.014314_1 - 014314_4, 2020/01

 Times Cited Count:5 Percentile:84.86(Physics, Nuclear)

The $$alpha$$-decay branching ratio of 0.52(5)% from the ground state of $$^{180}$$Pt to the ground state of the daughter nucleus $$^{176}$$Os has been determined more precisely than before. The $$^{180}$$Pt was produced as the $$beta$$-decay granddaughter of $$^{180}$$Hg which was produced and separated with the CERN-ISOLDE facility. The reduced $$alpha$$-decay width calculated with the present result has provided a new picture of the systematics for the $$alpha$$-decay width of neutron-deficient Pt isotopes.

Journal Articles

Fine structure in the $$alpha$$ decay of $$^{218}$$At

Cubiss, J. G.*; Andreyev, A. N.; Barzakh, A. E.*; Andel, B.*; Antalic, S.*; Cocolios, T. E.*; Day Goodacre, T.*; Fedorov, D. V.*; Fedosseev, V. N.*; Ferrer, R.*; et al.

Physical Review C, 99(6), p.064317_1 - 064317_6, 2019/06

 Times Cited Count:5 Percentile:69.53(Physics, Nuclear)

An $$alpha$$ decay of $$^{218}$$At was studied at the CERN-ISOLDE facility using a laser-ionization technique. Coincidence $$alpha$$-$$gamma$$ data were collected for the first time and a more precise half-life value of T$$_{1/2}$$ = 1.27(6) s was measured. A new $$alpha$$-decay scheme was deduced based on the fine-structure of the $$alpha$$ decay. The results lead to a preferred spin and parity assignment of J$$_{pi}$$ = (3$$^{-}$$) for the ground state of $$^{218}$$At; however, J$$_{pi}$$ = (2)$$^{-}$$ cannot be fully excluded.

Journal Articles

Identification of the crossing point at $$N$$ = 21 between normal and intruder configurations

Lic$u{a}$, R.*; Rotaru, F.*; Borge, M. J. G.*; Gr$'e$vy, S.*; Negoita, F.*; Poves, A.*; Sorlin, O.*; Andreyev, A. N.; Borcea, R.*; Costache, C.*; et al.

Physical Review C, 95(2), p.021301_1 - 021301_6, 2017/02

 Times Cited Count:12 Percentile:79.17(Physics, Nuclear)

Journal Articles

First ionization potential of the heaviest actinide lawrencium, element 103

Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Stora, T.*; Sato, Nozomi*; Kaneya, Yusuke; Tsukada, Kazuaki; D$"u$llmann, C. E.*; Eberhardt, K.*; Eliav, E.*; et al.

EPJ Web of Conferences, 131, p.05001_1 - 05001_6, 2016/12

 Times Cited Count:0 Percentile:0.9

Ionization efficiency in a surface ionization process depends on the first ionization potential of the atom. Based on the dependence, the ionization potential of the atom can be determined. We measured ionization efficiencies of fermium, einsteinium, mendelevium, and lawrencium by using a newly developed gas-jet coupled surface ion-source. The ionization potential of the elements have not been determined so far due to their low production rates and/or their short half-lives. Based on a relationship between the ionization efficiency and the ionization potential obtained via measurements of short-lived lanthanide isotopes, the ionization potentials of these actinide elements have been successfully determined.

Journal Articles

Local fields at nonmagnetic impurity sites in a perovskite $${rm La_{0.7}Ca_{0.3}MnO_3}$$

Sato, Wataru*; Komatsuda, Sayaka*; Osa, Akihiko; Sato, Tetsuya; Okubo, Yoshitaka*

Hyperfine Interactions, 237(1), p.113_1 - 113_6, 2016/12

 Times Cited Count:2 Percentile:67.01

The magnetic hyperfine field and electric field gradient at the$$^{111}$$Cd($$leftarrow$$ $$^{rm 111m}$$Cd) and $$^{rm 111}$$Cd($$leftarrow$$$$^{rm 111}$$In) probe nuclei introduced in a perovskite manganese oxide $${rm La_{0.7}Ca_{0.3}MnO_{3}}$$ ($$T_C$$ $$sim$$ 250 K) were measured for the study of the local magnetism and structure by means of time-differential perturbed angular correlation spectroscopy. In the ferromagnetic phase at 77 K, a very slight supertransferred magnetic hyperfine field (SMHF) ($$<$$ 0.014 T) combined with a well-defined electric field gradient was observed at the nonmagnetic $$^{111}$$Cd nucleus on the La/Ca A site. This observation suggests that the large magnetic hyperfine field ($$B_{hf}$$ = 6.9 T) measured, in our previous work, at the $$^{140}$$Ce probe nucleus on the A site originates from the contribution of a 4$$f$$ spin oriented by the SMHF from adjacent Mn ions.

Journal Articles

Internal decay of the (10$$^{-}$$) intruder state in $$^{184}$$Tl

Van Beveren, C.*; Andreyev, A. N.; Barzakh, A.*; Cocolios, T. E.*; Fedorov, D.*; Fedosseev, V. N.*; Ferrer, R.*; Huyse, M.*; K$"o$ster, U.*; Lane, J. F. W.*; et al.

Physical Review C, 92(1), p.014325_1 - 014325_8, 2015/07

 Times Cited Count:8 Percentile:57.47(Physics, Nuclear)

Journal Articles

Component tests on research and development of HTTR hydrogen production systems

Ohashi, Hirofumi; Nishihara, Tetsuo; Takeda, Tetsuaki; Inagaki, Yoshiyuki

Proceedings of 13th International Conference on Nuclear Engineering (ICONE-13) (CD-ROM), 8 Pages, 2005/05

A hydrogen production system connected to the High-Temperature Engineering Test Reactor (HTTR) is being designed to be able to produce hydrogen using a nuclear heat of 10 MW supplied by the HTTR. The HTTR hydrogen production system is first connected to a nuclear reactor in the world, hence an mock-up model test is planned to carry out prior to the demonstration test of the HTTR hydrogen production system. In parallel to the mock-up model test, the following tests as an essential problem, a corrosion test of a reforming tube, a permeation test of hydrogen isotopes through a heat exchanger tube, an integrity test of a high-temperature isolation valve, and a performance test of a hydrogen permselective membrane are carried out to obtain detailed data for a safety review and development of analytical codes. This paper describes the present status of the component tests on the R&D of the HTTR hydrogen production system.

Journal Articles

Proton-neutron configurations in $$^{236g,m}$$Am and its EC-decay daughter $$^{236}$$Pu

Asai, Masato; Sakama, Minoru*; Tsukada, Kazuaki; Ichikawa, Shinichi; Haba, Hiromitsu*; Nishinaka, Ichiro; Nagame, Yuichiro; Goto, Shinichi*; Kojima, Yasuaki*; Oura, Yasuji*; et al.

European Physical Journal A, 23(3), p.395 - 400, 2005/02

 Times Cited Count:12 Percentile:65.45(Physics, Nuclear)

The EC decay of $$^{236}$$Am has been studied through $$gamma$$-ray spectroscopy. Two EC-decaying states have been found in $$^{236}$$Am with half-lives of 3.6 min and 2.9 min. In $$^{236}$$Pu, we have found the $$K^{pi}=0^{-}$$ octupole band and two-quasiparticle states one of which is a $$K$$ isomer with a 1.2 $$mu$$s half-life. The EC transitions from $$^{236g,m}$$Am to the two-quasiparticle states in $$^{236}$$Pu show small $$log ft$$ values of 4.8--5.3, which allowed us to assign proton-neutron configurations of $$^{236g,m}$$Am and the two-quasiparticle states.

Journal Articles

Aging deterioration test of seismic isolation applied to fusion experimental reactor

Takeda, Nobukazu; Nakahira, Masataka; Kakudate, Satoshi; Takahashi, Hiroyuki*; Shibanuma, Kiyoshi; Yabana, Shuichi*; Matsuda, Akihiro*

Proceedings of 9th World Seminar on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures (CD-ROM), p.299 - 306, 2005/00

For the ITER, a fusion experimental reactor, it is planned to use rubber bearings in order to enhance the reliability of integrity with a sufficient margin even for the earthquakes beyond the design basis earthquake. In application for nuclear plants, the vertical compression of the isolator is 2$$sim$$5 MPa and there is no experience for such a high compression as 10 MPa to be used for the ITER. Therefore, there is not enough design data of the rubber bearings with high compression, and thus a detailed estimation of performance is necessary. As a result of the endurance test after aging, it was validated that the bearing can be applied safely until 400th cycle even after 40 years of aging. On the other hand, the residual deformation was found at the 246th cycle. This means that the residual deformation can be observed enough earlier than the change of the macroscopic mechanical parameter such as stiffness. Therefore, it is possible to prevent break of the bearing during operation by sensing a sign of break with a periodical visual inspection.

Journal Articles

Status on seismic design and verification for ITER in Japan

Takeda, Nobukazu; Nakahira, Masataka; Tada, Eisuke; Fujita, Satoshi*; Fujita, Takafumi*

Nihon Jishin Kogakkai Rombunshu (Internet), 4(3), p.298 - 304, 2004/04

ITER is a Tokamak-type international fusion experimental device composed of superconducting magnets, a vacuum vessel, and so on. These are operated at a quie wide temperature ranging from 4K to 200 degree C. For this, multiple plates have been chosen as the machine support so as to peovide flexibility in the radial direction while keeping high rigidity vertically. This results in a low natural frequency of around 4Hz in the horizontal direction. Since those structures are designed in accordance with the IAEA seismic acceleration of 0.2g as a reference, a seismic isolation is required if earthquake-proof larger than 0.2g is necessary. Considering these conditions, analytical and experimental studies have been conducted to characterize the ITER dynamic response in Japan. This paper outlines the latest status on seismic design for ITER in Japan and evaluation on tokamak dynamic response and verification tests using scaled tokamak model.

Journal Articles

Flow scheme and controllability of the HTTR hydrogen production system

Nishihara, Tetsuo; Shimizu, Akira; Inagaki, Yoshiyuki; Tanihira, Masanori*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 2(4), p.517 - 524, 2003/12

no abstracts in English

Journal Articles

Development of positron-emitting bromine nuclides production using an isotope separator

Fateh, B.; Ishioka, Noriko; Watanabe, Satoshi; Kume, Tamikazu; Sekine, Toshiaki*

JAERI-Review 2003-033, TIARA Annual Report 2002, p.259 - 261, 2003/11

no abstracts in English

Journal Articles

A Laser ion source with a thin ohmic-heating ionizer for the TIARA-ISOL

Koizumi, Mitsuo; Osa, Akihiko; Oshima, Masumi; Sekine, Toshiaki; Wakui, Takashi*; Jin, W.*; Katsuragawa, H.*; Miyatake, Hiroari*; Ishida, Yoshihisa*

Nuclear Instruments and Methods in Physics Research B, 204(1-4), p.359 - 362, 2003/05

 Times Cited Count:7 Percentile:47.94(Instruments & Instrumentation)

no abstracts in English

Journal Articles

The JAERI-KEK joint RIB project

Takeuchi, Suehiro

AIP Conference Proceedings 680, p.229 - 236, 2003/00

JAERI and KEK-Institute of Particle and Nuclear Studies are collabarating to build an ISOL-type radioactive ion beam(RIB) acceleration system in the JAERI-Tokai tandem accelerator lab. In this project, the tandem accelerator is used as a proton beam driver to create RIB from fission products of a uranium target and a RIB accelerator already built by KEK will be installed in an old target room of the tandem accelerator lab. The beam energy is 1.1 MeV/nucleon, which is not sufficient for experiments related to nuclear reactions. They have a plan to boost the beams to 5 - 9 MeV/u by developing a pre-booster and using existing super-conducting tandem-booster. The plan of this project, acceleration divices and present status will be outlined in the RIB session of the CAARI.

Journal Articles

Design of the ITER tritium plant, confinement and detritiation facilities

Yoshida, Hiroshi; Glugla, M.*; Hayashi, Takumi; L$"a$sser, R.*; Murdoch, D.*; Nishi, Masataka; Haange, R.*

Fusion Engineering and Design, 61-62, p.513 - 523, 2002/11

 Times Cited Count:25 Percentile:83.26(Nuclear Science & Technology)

ITER tritium plant is composed of tokamak fuel cycle systems, tritium confinement and detritation systems. The tokamak fuel cycle systems, composed of various tritium sumsystems such as vacuum vessel cleaning gas processing, tokamak exhaust processing, hydrogen isotope separation, fuel storage, mixing and delivery, and external tritium receiving and long-term storage, has been designed to meet not only ITER operation scenarios but safety requirements (minimization of equipment tritium inventory and reduction of environmental tritium release at different off-normal events and accident scenarios). Multiple confinement design was employed because tritium easily permeates through metals (at $$>$$ 150 $$^{circ}$$C) and plastics (at ambient temperature) and mixed with moisture in room air. That is, tritium process equipment and piping are designed to be the primary confinement barrier, and the process equipments (tritium inventory $$>$$ 1 g) are surrounded by the secondary confinement barrier such as a glovebox. Tritium process rooms, which contains these facilities, form the tertiary confinement barrier, and equipped with emergency isolation valves in the heating ventillation and air conditioning ducts as well as atmosphere detritiation systems. This confinement approach has been applied to tokamak building, tritium building, and hotcell and radwaste building.

Journal Articles

Approach for safety assurance and structural integrity of ITER

Tada, Eisuke; Hada, Kazuhiko; Maruo, Takeshi; Safety Design/Evaluation Group

Purazuma, Kaku Yugo Gakkai-Shi, 78(11), p.1145 - 1156, 2002/11

no abstracts in English

Journal Articles

Estimation of mechanical characteristics of actual size rubber bearings with scale models

Yabana, Shuichi*; Matsuda, Akihiro*; Nakahira, Masataka; Osaki, Toshio*

Nihon Kenchiku Gakkai 2002-Nendo Taikai Koen Kogaishu, P. 495, 2002/08

no abstracts in English

JAEA Reports

Characteristic evaluation of high compression seismic isolator for International Thermonuclear Experimental Reactor (ITER); Verification test of sub-scaled rubber bearings (Contract research)

Takahashi, Hiroyuki*; Nakahira, Masataka; Yabana, Shuichi*; Matsuda, Akihiro*; Otori, Yasuki*

JAERI-Tech 2001-064, 111 Pages, 2001/11

JAERI-Tech-2001-064.pdf:8.96MB

no abstracts in English

59 (Records 1-20 displayed on this page)