On-site background measurements for the J-PARC E56 experiment; A Search for the sterile neutrino at J-PARC MLF

Ajimura, Shuhei*; Bezerra, T. J. C.*; Chauveau, E.*; Enomoto, T.*; Furuta, Hisataka*; Harada, Masahide; Hasegawa, Shoichi; Hiraiwa, T.*; Igarashi, Yoichi*; Iwai, Eito*; et al.

Progress of Theoretical and Experimental Physics (Internet), 2015(6), p.063C01_1 - 063C01_19, 2015/06

https://doi.org/10.1093/ptep/ptv078

The J-PARC E56 experiment aims to search for sterile neutrinos at the J-PARC Materials and Life Science Experimental Facility (MLF). In order to examine the feasibility of the experiment, we measured the background rates of different detector candidate sites, which are located at the third floor of the MLF, using a detector consisting of plastic scintillators with a fiducial mass of 500 kg. The gammas and neutrons induced by the beam as well as the backgrounds from the cosmic rays were measured, and the results are described in this article.

Thermodynamic properties of lanthanides and actinides for reductive ectraction of minor actinides

Toda, Taro*; Maruyama, Takehiro*; Moritani, Kimikazu*; Moriyama, Hirotake*; Hayashi, Hirokazu

Journal of Nuclear Science and Technology, 46(1), p.18 - 25, 2009/01

https://doi.org/10.3327/jnst.46.18

The excess thermodynamic quantities of lanthanides and actinides in molten salts and liquid metals were studied for reductive extraction of minor actinides. The excess enthalpies and entropies of those elements in the molten chloride phase were found to be correlated with the ionic radii of metal ions possibly due to complex formation. In the liquid metal phase, on the other hand, the excess enthalpies were explained with Miedema's atomistic model and the excess entropies were explained with the vibrational entropy due to alloy formation. Using these correlations and models, some missing values of the excess thermodynamic quantities were evaluated and the separation factors of minor actinides from lanthanides were calculated in different reductive extraction systems. The higher separation factors were obtained in the system using aluminum or gallium than in the system using bismuth or cadmium as the liquid metal phase.

Life assessment of Mod.9Cr-1Mo steel; Quantitative evaluation of microstructural damage in creep interrupted specimens and in creep-fatigue specimens

; ;

JNC TN9400 99-038, 30 Pages, 1999/02

JNC-TN9400-99-038.pdf:0.99MB

Boiler and steam turbine components in power generating plants are used under creep and creep-fatigue conditions. It is important to measure both creep and creep-fatigue damage of the components in order to assess the residual life of the components. Modified 9Cr-1Mo steel, a candidate material for steam generator in FBR, has a tempered martensitic lath structure. It was proposed in the second report that lath width in the lath structure is closely related to creep strain, and using this relation one can assess residual creep life of a structural component made of the steel. The objectives of this study are to investigate the change of the lath structure during creep-fatigue deformation, and to estimate creep strain by measuring area of cell composing the lath structure. The area of cell can be a better measure of creep deformation than the lath width. The lath structure recovers during creep-fatigue deformation. The lath structure becomes equiaxed cell structure under creep-fatigue more quickly compared with the lath structure recovered during creep. The lath structure recovered under creep-fatigue has a stationary value of the lath width determined by maximum stress at Nf/2. (Nf: number of cycles) If the recovery process of the lath structure can be investigated under creep-fatigue, the lath width can be a measure of the life assessment under creep-fatigue. Area of cell composing the lath structure increases with creep deformation and reaches a stationary value S determined by creep stress. The rate of increase in the area is faster at a higher stress and temperature. A normalized change in the area of cel, S /S, was introduced as a measure of the recovery process of martensitic lath structure. S is the change in area of cell from the initial value S, S is the difference between S and S. S/S is uniquely related to creep strain independent of creep conditions. However, the sca

Creep life assessment of Mod.9Cr-1Mo steel, 1; Quantitative evaluation of microstructural damage in creep rupture specimens

Sawada, Kota; Maruyama, Koichi; Komine, Ryuji; Nagae, Yuji

PNC TN9410 97-035, 41 Pages, 1997/03

PNC-TN9410-97-035.pdf:1.87MB

Several microstructural changes take place in a material during the course of creep. These changes can be a measure of creep life consumption. In this paper, microstructural changes in Mod.9Cr-1Mo steel were studied in order to examine their ability as the measure of crecp life consumption. Macroscopic structural changes, such as void growth, rotation of lath structure toward the tensile axis and elongation of grains, are evident only in the necked portion of ruptured specimens. These macroscopic structural changes are not useful for creep life assessment. Lath width increases and dislocation density within lath decreases with increasing creep duration. These changes in dislocation substructure start in the early stage of creep life, and cause the increase of strain rate in the tertiary creep stage. The lath width and the dislocation density reach a stationary value before rupture. The stationary values are independent of temperature, and uniquely related to creep stress normalized by shear modulus. The extent of these microstructural changes are greater at lower stresses under which the material is practically used. These facts suggest that the lath width and the dislocation density within lath can be a useful measure of creep life consumption. Hardness of crept specimens is closely related to the lath width and the dislocation density within lath. The changes of these microstructural features can be evaluated by the measurement of handness.

None

Maruyama, Koichi*; Aoto, Kazumi

PNC TN9000 96-005, 3 Pages, 1996/05

PNC-TN9000-96-005.pdf:0.11MB

None

Present and future statuses of search experiment for sterile neutrino at MLF of J-PARC

Meigo, Shinichiro; Hasegawa, Shoichi; Nishikawa, Yuichiro; Maruyama, Takasumi*; Iwai, Eito*; Ota, Ryosuke*

no journal, , 

no abstracts in English