Irradiation growth behavior of improved Zr-based alloys for fuel cladding

Amaya, Masaki; Kakiuchi, Kazuo; Mihara, Takeshi

Proceedings of International Nuclear Fuel Cycle Conference / Light Water Reactor Fuel Performance Conference (Global/Top Fuel 2019) (USB Flash Drive), p.1048 - 1056, 2019/09

Online chemical adsorption studies of Hg, Tl, and Pb on SiO and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA

Lens, L.*; Yakushev, A.*; Dllmann, Ch. E.*; Asai, Masato; Ballof, J.*; Block, M.*; David, H. M.*; Despotopulos, J.*; Di Nitto, A.*; Eberhardt, K.*; et al.

Radiochimica Acta, 106(12), p.949 - 962, 2018/12

https://doi.org/10.1515/ract-2017-2914

Online gas-solid adsorption studies with single atom quantities of Hg, Tl, and Pb on SiO and Au surfaces were carried out using short-lived radioisotopes with half-lives in the range of 4-49 s. This is a model study to measure adsorption enthalpies of superheavy elements Cn, Nh, and Fl. The short-lived isotopes were produced and separated by the gas-filled recoil separator TASCA at GSI. The products were stopped in He gas, and flushed into gas chromatography columns made of Si detectors whose surfaces were covered by SiO or Au. The short-lived Tl and Pb were successfully measured by the Si detectors with the SiO surface at room temperature. On the other hand, the Hg did not adsorb on the SiO surface, but adsorbed on the Au surface. The results demonstrated that the adsorption properties of short-lived Hg, Tl, and Pb could be studied with this setup, and that this method is applicable to the experiment for Cn, Nh, and Fl.

Petrographic data of silicic igneous rocks in the Tono area, central Japan

Ueki, Tadamasa; Niwa, Masakazu

JAEA-Data/Code 2018-005, 94 Pages, 2018/08

JAEA-Data-Code-2018-005.pdf:15.6MB

Mountain development has an influence on long-term changes of uplift, erosion, and groundwater flow related to change in hydraulic gradient. Provenance analysis is one of promising geological methods to understand origin and formation process of mountains. Case study in the Tono area, central Japan has been done for research and development of individual technique to estimate a provenance. In this report, petrological descriptions by meso- and microscopic observations and elemental distributions using scanning X-ray analytical microscope of basement rocks (silicic igneous rocks) from the study area were compiled.

Polar rotor scattering as atomic-level origin of low mobility and thermal conductivity of perovskite CHNHPbI

Li, B.; Kawakita, Yukinobu; Liu, Y.*; Wang, M.*; Matsuura, Masato*; Shibata, Kaoru; Kawamura, Seiko; Yamada, Takeshi*; Lin, S.*; Nakajima, Kenji; et al.

Nature Communications (Internet), 8, p.16086_1 - 16086_9, 2017/06

https://doi.org/10.1038/ncomms16086

A Remote-operated system to map radiation dose in the Fukushima Daiichi primary containment vessel

Nancekievill, M.*; Jones, A. R.*; Joyce, M. J.*; Lennox, B.*; Watson, S.*; Katakura, Junichi*; Okumura, Keisuke; Kamada, So*; Kato, Michio*; Nishimura, Kazuya*

Proceedings of 5th International Conference on Advancements in Nuclear Instrumentation Measurement Methods and their Applications (ANIMMA 2017) (USB Flash Drive), 6 Pages, 2017/06

We are developping a submersible ROV system, coupled with radiation detectors aimed at mapping the interior of the reactors at the Fukushima Daiichi Nuclear Power Station. To map the -ray intensity environment a cerium bromide (CeBr) inorganic scintillator detector sensitive to -rays has been incorporated into the ROV to measure -ray intensity and identify radioactive isotopes. The ROV is a cylindrical shape with a diameter of about 150 mm, and it have two end caps of five pumps each allowing control of the ROV in 5 degree of freedom. It is possible to directly replace the CeBr detector with a single crystal chemical vapour deposition (CVD) neutron detector with a Li convertor foil that is capable of mapping the thermal neutron flux.

Thermophysical properties of americium-containing barium plutonate

Tanaka, Kosuke; Sato, Isamu; Hirosawa, Takashi; Kurosaki, Ken*; Muta, Hiroaki*; Yamanaka, Shinsuke*

Journal of Nuclear Science and Technology, 52(10), p.1285 - 1289, 2015/10

https://doi.org/10.1080/00223131.2015.1029554

Polycrystalline specimens of americium-containing barium plutonate have been prepared by mixing the appropriate amounts of (PuAm)O and BaCO powders followed by reacting and sintering at 1600 K under the flowing gas atmosphere of dry-air. The sintered specimens had a single phase of orthorhombic perovskite structure and were crack-free. The elastic moduli were determined from the longitudinal and shear sound velocities. The Debye temperature was also determined from the sound velocities and lattice parameter measurements. The thermal conductivity was calculated from the measured density at room temperature, literature values of heat capacity, and thermal diffusivity measured by laser flash method in vacuum. The thermal conductivity of americium-containing barium plutonate was roughly independent of the temperature and was almost the same magnitude as that of BaPuO and BaUO.

On the requirement for remodelling the spent nuclear fuel transportation casks for research reactors; A Review of the drop impact analyses of JRC-80Y-20T

Review Group on the Structure of the Spent Nuclear Fuel Transportation Casks for

JAERI-Review 2005-023, 133 Pages, 2005/07

JAERI-Review-2005-023.pdf:18.88MB

The Japan Atomic Energy Research Institute (JAERI) constructed two stainless steel transportation casks, JRC-80Y-20T, for spent nuclear fuels of research reactors and had utilized them for transportation since 1981. A modification of the design was applied to the USA for transportation of silicide fuels. Additional analyses employing the impact analysis code LS-DYNA that was often used for safety analysis were submitted by the JAERI to the USA to show integrity of the packages; the casks were still not approved, because inelastic deformation was occurred on the surface of the lid touching to the body. To resolve this problem on design approval of transportation casks, a review group was formed at the end of this June. The group examined the impact analyses by reviewing the input data and performing the sensitivity analyses. As the drop impact analyses were found to be practically reasonable, it was concluded that the approval of the USA for the transportation casks could not be obtained just by revising the analyses; therefore, remodelling the casks is required.

Numerical study of zonal flow dynamics and electron transport in electron temperature gradient driven turbulence

Li, J.; Kishimoto, Yasuaki

Physics of Plasmas, 11(4), p.1493 - 1510, 2004/04

https://doi.org/10.1063/1.1669397

The electron temperature gradient (ETG) driven turbulence in tokamak core plasmas is numerically investigated based on three-dimensional gyrofluid model with adiabatic ion response. Attentions are focused on the zonal flow dynamics in ETG fluctuations and the resultant electron heat transport. A high electron energy confinement mode is found in the weak magnetic shear regime, which is closely relevant with self-organization behavior of turbulence through the enhanced zonal flow dynamics rather than the weak shear stabilization of ETG fluctuations. It is demonstrated that the weak shear is favorable for the enhancement of zonal flows in ETG turbulence.

Charge disproportionation and magnetic properties in perovskite iron oxides

Kuzushita, Kaori; Morimoto, Shotaro*; Nasu, Saburo*

Physica B; Condensed Matter, 329-333(1-4), p.736 - 737, 2003/05

https://doi.org/10.1016/S0921-4526(02)02478-X

The physical properties of perovskite iron oxides are closely related to the network of FeO octahedra. The charge disproportionation (2Fe Fe + Fe), not observed in SrFeO, occurs in the oxides being cut the network of FeO octahedra, for example, by introduction of Fe by substitution La for Sr and change in the dimension by insertion of SrO layer. When Co is substituted 40% of Fe in SrFeO, the magnetic order changes to ferromagnetic from antiferromagnetic and charge disproportionation is suppressed.

Thermal hydraulic analysis of the JMTR improved LEU-core

Tabata, Toshio; Nagao, Yoshiharu; Komukai, Bunsaku; Naka, Michihiro; Takeda, Takashi*; Fujiki, Kazuo

JAERI-Tech 2002-100, 108 Pages, 2003/01

JAERI-Tech-2002-100.pdf:4.44MB

After the investigation of the new core arrangement for the JMTR reactor in order to enhance the fuel burn-up and consequently extend the operation period, the "improved LEU core" that utilized 2 additional fuel elements instead of formerly installed reflector elements, was adopted. This report describes the results of the thermal-hydraulic analysis of the improved LEU core as a part of safety analysis for the licensing. The analysis covers steady state, abnormal operational transients and accidents, which were described in the annexes of the licensing documents as design bases events. Calculation conditions for the computer codes were conservatively determined based on the neutronic analysis results and others. The results of the analysis, that revealed the safety criteria were satisfied on the fuel temperature, DNBR and primary coolant temperature, were used in the licensing. The operation license of the JMTR with the improved LEU core was granted in March 2001, and the reactor operation with new core started in November 2001 as 142nd operation cycle.