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Hashiba, Kimihiro*; Fukui, Katsunori*; Sugita, Yutaka; Sanada, Masanori*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 21(2), p.75 - 82, 2014/12
Diatomaceous earth and siliceous rock are widespread in the areas along the Sea of Japan in Hokkaido Prefecture, Akita Prefecture, Noto Peninsula and Oki Islands. To construct underground structures in the siliceous rock mass, it is essential to understand its mechanical properties. In this study, siliceous mudstone of the Wakkanai formation obtained from the deep underground in Horonobe, Hokkaido was applied to various laboratory tests; uniaxial compression test, Brazilian tension test, drying shrinkage test and the test to investigate the time dependent behavior and strength recovery. The testing results showed that water has a huge effect on the deformation and failure of the siliceous mudstone; when the specimen is air dried in room temperature, the axial shrinkage strain reashes 0.9% and the strength is twice larger than that in wet condition. It was found that the siliceous mudstone exhibits the same degree of time dependent behavior and strength recovery as other rocks such as tuff and sandstone.
Sugita, Yutaka; Sanada, Masanori; Fujita, Tomoo; Hashiba, Kimihiro*; Fukui, Katsunori*; Okubo, Seisuke*
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.207 - 212, 2013/01
Radionuclide migration can be undesirably increased by weakening the mechanical properties of a rock mass in the excavated disturbed zone (EDZ) around the tunnels of a geolical disposal facility for high level radioactive waste. Laboratory testing of loading stress and loading time on failed siliceous mudstone specimens has identified the potential for the long-term recovery of the strength and impermeability of the rock mass in the EDZ.
Katsunuma, Yoshio*; Higuchi, Masanori*; Shiba, Akihiro*; Kataigi, Isao*
JNC TJ7410 2005-011, 64 Pages, 2004/02
JNC-TJ7410-2005-011.PDF:14.94MB
no abstracts in English
complexMiyahara, Sachiko; *; Shiba, Masanori*; *; ; *;
JNC TN8400 2002-014, 40 Pages, 2002/05
JNC-TN8400-2002-014.pdf:1.57MB
The current technology for the selective separation of plutonium and uranium from spent nuclear fuel (MOX) using TBP-HNO complex is being developed (Powdered fuel extraction process). It is promising to simplify the reprocessing process for the selective separation because of its potential to unite the chemical processes, dissolution process using nitric acid and co-extraction process using TBP solvent, and to operate under the ambient pressure and at relatively "mild" temperature. Plutonium oxide has reported to provide slower dissolution than uranium oxide in nitric acid. In this work dissolution behaviors of plutonium into TBP-HNO complex from powdered plutonium and uranium mixed oxide were examined. The powdered MOX fuel (average particles size 10
m) was prepared from PuO
-O pellets by heating for 4 hours at 400
C. The prepared powder was dissolved into TBP-4.74mol/L HNO complex and was stirred for 300 minutes. In the test with 6 grams of powdered MOX fuel and 20 mL of the TBP-HNO complex, the concentration of plutonium reached 0.17 mol/L and about 90 percent of plutonium was dissolved. It is experimentally confirmed plutonium was dissolved into the TBP-HNO complex from plutonium and uranium mixed oxide. The early dissolution rate was almost the same as that obtained with nitric acid solution. It is likely to predict the dissolution rate from the rate for nitric acid solution. Americium that was contained in the MOX fuel was also dissolved into the TBP-HNO complex, but was slower than plutonium.
; ; ; ; Wada, Koji; *; *; Suzuki, Shinji*; Shiba, Masanori*
PNC TN853 83-02, 187 Pages, 1983/08
no abstracts in English
