Carrying-out of whole nuclear fuel materials in Plutonium Research Building No.1

Inagawa, Jun; Kitatsuji, Yoshihiro; Otobe, Haruyoshi; Nakada, Masami; Takano, Masahide; Akie, Hiroshi; Shimizu, Osamu; Komuro, Michiyasu; Oura, Hirofumi*; Nagai, Isao*; et al.

JAEA-Technology 2021-001, 144 Pages, 2021/08

JAEA-Technology-2021-001.pdf:12.98MB

Plutonium Research Building No.1 (Pu1) was qualified as a facility to decommission, and preparatory operations for decommission were worked by the research groups users and the facility managers of Pu1. The operation of transportation of whole nuclear materials in Pu1 to Back-end Cycle Key Element Research Facility (BECKY) completed at Dec. 2020. In the operation included evaluation of criticality safety for changing permission of the license for use nuclear fuel materials in BECKY, cask of the transportation, the registration request of the cask at the institute, the test transportation, formulation of plan for whole nuclear materials transportation, and the main transportation. This report circumstantially shows all of those process to help prospective decommission.

Preliminary missions for the decommissioning of the laboratory building No.1 for the plutonium research program

Segawa, Yukari; Horita, Takuma; Kitatsuji, Yoshihiro; Kumagai, Yuta; Aoyagi, Noboru; Nakada, Masami; Otobe, Haruyoshi; Tamura, Yukito*; Okamoto, Hisato; Otomo, Takashi; et al.

JAEA-Technology 2016-039, 64 Pages, 2017/03

JAEA-Technology-2016-039.pdf:5.24MB

The laboratory building No.1 for the plutonium research program (Bldg. Pu1) was chosen as one of the facilities to decommission by Japan Atomic Energy Agency Reform in September, 2013. The research groups, users of Bldg. Pu1, were driven by necessity to remove used equipment and transport nuclear fuel to other facilities from Bldg. Pu1. Research Group for Radiochemistry proactively established the Used Equipment Removal Team for the smooth operation of the removal in April, 2015. The team classified six types of work into the nature of the operation, removal of used equipment, disposal of chemicals, stabilization of mercury, stabilization of nuclear fuel, transportation of nuclear fuel and radioisotope, and survey of contamination status inside the glove boxes. These works were completed in December, 2015. This report circumstantially shows six works process, with the exception of the approval of the changes on the usage of nuclear fuel in Bldg. Pu1 to help prospective decommission.

Microscopic evidence for long-range magnetic ordering in the ground quartet systems SmAl (: Ti, V, Cr)

Ito, Takashi; Higemoto, Wataru; Ninomiya, Kazuhiko; Sakai, Akito*; Nakatsuji, Satoru*

Journal of the Physical Society of Japan, 81(Suppl.B), p.SB050_1 - SB050_4, 2012/12

https://doi.org/10.1143/JPSJS.81SB.SB050

Recently, Al compounds (: rare earth, : transition metal) have attracted much attention due to interesting physical properties closely related to their caged-structure. Each ion is confined in a Frank-Kasper cage consisting of 16 Al atoms and the large coordination number leads to strong - hybridization. In addition, the Frank-Kasper cage allows various multipole degrees of freedom for the -electrons at low because of a highly symmetric crystalline-electric-field (CEF). Among the Al series, PrAl (: Ti, V) and SmAl (: Ti, V, Cr) exhibit both these features. The ground doublet systems PrAl (: Ti, V) show a phase transition at = 2.0K (Ti) and 0.6K (V). The order parameter is believed to be an electric quadrupole active in the subspace. A possibility of the quadrupole Kondo effect has been discussed based on characteristic -dependence in specific heat, resistivity, and magnetic susceptibility. The ground quartet systems SmAl (: Ti, V, Cr) also exhibit a phase transition at = 6.4K (Ti), 2.3K (V), and 1.8K (Cr). A nuclear specific heat study in SmTiAl suggests that the primary order parameter is a magnetic dipole in spite of field-insensitive nature of the phase boundary. A possible importance of a secondarily ordered octupole moment was discussed. We here present a microscopic study of PrTiAl and SmAl (: Ti, V, Cr) using muon spin relaxation. In PrTiAl, no additional local field was observed in the ordered phase. This strongly supports the quadrupole ordering scenario. On the other hand, an appearance of a coherent local field was observed below in SmAl. This is consistent with the primary magnetic dipole ordering. The frequency distribution suggests that the magnetic structure is possibly different between the SmAl compounds.

Spin-orbital short-range order on a honeycomb-based lattice

Nakatsuji, Satoru*; Kuga, Kentaro*; Kimura, Kenta*; Satake, Ryuta*; Katayama, Naoyuki*; Nishibori, Eiji*; Sawa, Hiroshi*; Ishii, Rieko*; Hagiwara, Masayuki*; Bridges, F.*; et al.

Science, 336(6081), p.559 - 563, 2012/05

https://doi.org/10.1126/science.1212154

Frustrated magnetic materials can remain disordered to the lowest temperatures. Such is the case for BaCuSbO, which is magnetically anisotropic at the atomic scale but curiously isotropic on mesoscopic length and time scales. We find that the frustration on the triangular lattice is imprinted in a nanostructured honeycomb lattice of Cu ions that resists a coherent static Jahn-Teller distortion. The resulting two-dimensional random-bond spin-1/2 system on the honeycomb lattice has a broad spectrum of spin-dimer like excitations and low-energy spin degrees of freedom that retain.

Test execution of liquid-type grout at depth of 300m of Mizunami Underground Research Laboratory

Nobuto, Jun*; Tsuji, Masakuni*; Kusano, Takashi*; Mikake, Shinichiro; Kamiya, Akira; Ishii, Yoji

Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.179 - 184, 2011/01

At Mizunami Underground Research Laboratory, the water inflow should be minimized, considering water treatment expense. Although cement grout has been applied to reduce water inflow up to 460 m depth, water inflow through small fractures which cement grout cannot penetrate can not be neglected at deeper underground. Liquid-type grout which has high durability as well as good penetrability was therefore tested at the depth of 300 m. Test results indicated that liquid-type grout could sufficiently reduce hydraulic conductivity of rock mass with less than 1Lu, and could keep improvement effect even after applied water pressure of more than 9 MPa was applied.

Pressure dependence of the structure of liquid Sn up to 19.4 GPa

Narushima, Takashi*; Hattori, Takanori; Kinoshita, Tomohiro*; Hinzmann, A*; Tsuji, Kazuhiko*

Physical Review B, 76(10), p.104204_1 - 104204_8, 2007/09

https://doi.org/10.1103/PhysRevB.76.104204

The structure of liquid Sn was investigated up to 19.4 GPa by synchrotron X-ray diffraction. Upon compression up to about 3-6 GPa, the structural features, which reflect the anisotropic local structure become less prominent; i.e., the hump on the high- side of the first peak in the structure factor becomes smaller, the position of the second peak relative to that of the first peak in , , decreases, and the coordination number, CN, increases. These features indicate that the liquid structure changes toward a simple liquid metal upon compression. However, at higher pressures, the structural parameters nearly unchanged. The parameters in this pressure range are still deviated from their respective values for simple liquid metals. These findings suggest that, contrary to previous expectations, the liquid does not monotonically approach a simple liquid metal, but takes a relatively stable intermediate form with an anisotropic local structure before approaching a simple liquid metal. The high-pressure behavior of liquid Sn is compared to those of liquid Si and liquid Ge and the systematics in liquid group 14 elements are discussed.

Pressure-induced structural change of liquid CdTe up to 23.5GPa

Hattori, Takanori; Kinoshita, Tomohiro*; Narushima, Takashi*; Tsuji, Kazuhiko*; Katayama, Yoshinori

Physical Review B, 73(5), p.054203_1 - 054203_9, 2006/02

https://doi.org/10.1103/PhysRevB.73.054203

The structure of liquid CdTe was investigated at pressures up to 23.5GPa using synchrotron X-ray diffraction. The structure factor, S(Q), and the pair distribution function, g(r), drastically change in two pressure regions, 1.8-3.0 GPa and 7.0-9.0 GPa, accompanied with marked increase in the average coordination number, CN. These findings suggest that there exists at least three stable liquid forms below 23.5GPa. The pressure interval of the structural change is much smaller compared to other liquids of tetrahedrally bonded materials. Comparing the shapes of S(Q) and g(r), and other structural parameters with the respective data for the reference materials reveals that the lowest- and intermediate-pressure forms have the same local structures as the crystalline counterpart (zinc-blende-like local structure and a NaCl-like local structure), while the highest-pressure form has a different local structure from that in the crystalline form.

Application of Log Interpretation Methods to Evaluate Heterogeneity in Diatomaceous Mudstone at Horonobe Area

Hara, Akio; Tsuji, Takashi*; Hoshi, Kazuyoshi*; Yagi, Masahiko*; Nishimura, Mizue*; Kawada, Koji*; Hou, J.-Y.*

Program and Abstracts, p.65, P. 65, 2005/02

To evaluate heterogeneity of diatomaceous mudstone in Horonobe area, physical properties and lithofacies of sedimentary rocks have been estimated from natural ray log data and electrical micro imaging (EMI) log data. Spatial distribution of heterogeneity of sedimentary rocks has been discussed by comparison of log data acquired from several boreholes. Five sedimentary facies, A to E, have been established. Sedimentary facies A and B, which can decipher bedding planes clearly in EMI image, have been developed horizontally with low ray and high SiOcontents while sedimentary facies D, bedding planes are not clear to decipher, have been developed horizontally with high ray and low SiOcontents. The results of this study support the estimation of Hara (2004) namely the strata which characterized with high ray have been high AlOcontents and rich in terrigenous sediments such as clay minerals, on the other hand, the strata characterized with low ray have high SiOcontents and rich in diatomaceous fossils. Layered sedimentary facies can correlate between boreholes based on natural ray log and EMI log analysis. Sedimentary system and spatial distribution of strata of Horonobe area can estimate from the results of the facies correlation.

Study on a Method to Evaluate Heterogeneity of Sedimentary Rocks Using a Forward Model, II

Hoshi, Kazuyoshi*; Hou, J.-Y.*; Kawada, Koji*; Tsuji, Takashi*; Suwabe, Mizue*

JNC TJ8400 2005-008, 138 Pages, 2005/01

JNC-TJ8400-2005-008.pdf:25.65MB

Developing a method to evaluate heterogeneity of sedimentary rocks is very important for a site survey and a property test of the site. We studied siliceous shale from wells in the Horonobe area, and developed a sedimentary process modeling software in order to establish a method to evaluate heterogeneity of sedimentary rocks. Well log analysis of Koetoi and Wakkanai Formations revealed variations of porosity, shale content, and amount of erosion. We correlate marker beds, and establish a compaction curve for siliceous shale in the Horonobe area. EMI analysis revealed alternation of thin beds which can not been recognized by naked eyes. Chemical analysis shows that this heterogeneity originates from a variation in diatom and clastic material contents in the rock. We also examined seismic data using GDI method. For sedimentary modeling software, we expanded the sedimentary simulation module, and attached another module to compare the calculated results with actual data. We also attached the module to find the best input parameters. We performed a test run using the geology model we made for Horonobe area.

Study on Evaluation Method for Heterogeneous Sedimentary Rocks Based on Forward Model

Kato, Arata*; Kawada, Koji*; Masui, Yasuhiro*; Tsuji, Takashi*; Suwabe, Mizue*

JNC TJ8400 2003-093, 178 Pages, 2004/02

JNC-TJ8400-2003-093.pdf:5.72MB

It is very important to estimate the facies distribution of heterogeneous sedimentary rocks for geological disposal of high level radioactive waste. The heterogeneousness of sedimentary rocks is due to variable distribution of grain size and mineral composition. The objective of this study is to establish the evaluation method for heterogeneous sedimentary rocks based on forward model. In this study, the following items were studied. 1..The sedimentary system for Koetoi and Wakkanai formations in Horonobe area was compiled based on published papers. 2..The cores of HDB-1 were observed mainly from sedimentological view. 3..The facies and compaction property of argillaceous rocks were studied based on physical logs and core analysis data of wells. 4..The structure maps, isochrone maps, isopach maps and restored geological sections were made. 5..The soft wear for sedimentary model to show sedimentary system on a basin scale was developed.