Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Tashiro, Shinsuke; Amano, Yuki; Yoshida, Kazuo; Yamane, Yuichi; Uchiyama, Gunzo; Abe, Hitoshi
Nihon Genshiryoku Gakkai Wabun Rombunshi, 14(4), p.227 - 234, 2015/12
The release characteristics of Ru from highly active liquid waste (HALW) have been investigated under the condition of accidental evaporation to dryness by boiling of HALW. Using a laboratory-scale apparatus, non-radioactive simulated HALW (s-HALW) was heated with an external heater to dryness to observe the release characteristics of Ru and gaseous nitrogen oxides. As a result, Ru was significantly released between 120 and 300 
C of the s-HALW. The cumulative release ratio of Ru was 0.088. It was also found that the partially released amount of Ru against the temperature of the s-HALW had two peaks with one maximal at about 140 C and maximum at about 240 C. Referring to the results of the release rate of gaseous nitrogen oxides and the volume of condensate, which was a collection of the mixed vapors of steam and nitric acid released from the s-HALW, we discussed the causes of Ru release around these peaks.
Mine, Tatsuya*; Mihara, Morihiro;
JNC TN8430 2000-009, 35 Pages, 2000/07
JNC-TN8430-2000-009.pdf:0.88MB
In the geological disposal system of TRU wastes, nitrogen generation by denitrifying bacteria could provide significant impact on the assessment of this system, because nitrate contained in process concentrated liquid waste might be electron acceptor for denitrifying bacteria. In this study, the activities and tolerance of denitrifying bacteria under disposal condition were investigated. pseudomonas denitrificans as denitrifying bacteria was used. The results showed that Pseudomonas denitrificans had activity under reducing condition, but under high pH condition (PH
9.5), the activity of Pseudomonas denitrificans was not detected. It is possible that the activity of Pseudomonas denitrificans would be low under disposal condition.
Mine, Tatsuya*; Mihara, Morihiro; ; *; *
JNC TN8430 2000-003, 33 Pages, 2000/04
On the geological disposal system of the radioactive wastes, the activities of the microorganisms that could degrade the asphalt might be significant for the assessment of the system performance. As the main effects of the biodegradation of the asphalt, the fluctuation of leaching behavior of the nuclides included in asphalt waste has been indicated. In this study, the asphalt biodegradation test was carried out. The microorganism of which asphalt degradation ability was comparatively higher under aerobic condition and anaerobic condition was used. The asphalt biodegradation rate was calculated and it was evaluated whether the asphalt biodegradation in this system could occur. The results show that the asphalt biodegradation rate under anaerobic and high alkali condition will be 300 times lower than under aerobic and neutral pH.
; ; ; ; *
PNC TN8410 93-046, 46 Pages, 1993/03
The TRUEX process has been developed to recover transuranium elements from high level liquid waste. This process uses octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) which is able to extract tri-valent actinides. It is already well known that a third phase appears at the interface when rare earths and other metal ions are extracted from a concentrated solution into TRUEX solvent which consists of CMPO with TBP - dodecane mixture. The basic researches concerning behavior of third phase formation and elimination were done in previous experiments. Succseively, dependency of temperature on organic phase composition, behavior of U extraction, applicability to high level liquid waste and diluent effect were investigated in these experiments. Consequently, these results were made obviously. By composition analysis of solvent which extracted nitric acid, it was found that not only concentration of extracted species, but temperature also influences on the composition of split phase. Extraction of high uranium concentration caused yellow precipitation. Critical concentration for precipitation were constant in each system and not dependent on temperature significantly. This precipitation was considered to affect extraction procedure, so that the condition should be selected carefully. In experiment using simulated waste, it's found that with appropriate condition of TBP concentration and temperature, dilution of concentrated liquid waste would not be necessary. From this work, 1.4 M for TBP concentration and 40 C are promisible and that are typical values for concentrated waste. However, to determine the practical conditon for real waste treatment, further experiments should be done. From comparison of hydrocarbon composed of 12 carbons with n-dodecane as diluent, carbon chain length and banching influence on critical concentration of third phase formation.
; Nomura, Kazunori; ; ; Kuno, Yusuke
PNC TN8410 92-172, 112 Pages, 1992/06
Basic distribution studies and counter-current flowsheet experiments employing a mixture of CMPO with TBP as a reference solvent were conducted to evaluate the applicability of the TRUEX process to high level liquid wastes(HLLW) generated from the PUREX reprocessing process. Real highly active raffinate (HAR) solutions were used for these experiments. Concerning the major nuclide components of HLLW, various effecting factors on D values such as acidity, temperature, the ratios of CMPO/TBP and components concentration were investigated, respectively. Earlier (the first and second) counter-current flowsheet runs with laboratory scale mixer-settlers have shown excellent capability of the TRUEX process for actinides separation from real HAR solution. However, these tests showed unexpected significant retention of ruthenium and plutonium in the solvent. In the successive third run, some improvements to increase separation factor of these two nuclides and neptunium were demonstrated. This annual report summarizes results derived from the counter-current runs and basic study that treat the distribution of Np (IV, V, VI), other actinides and fission products, and the solubilities of extracted complexes to clarify the third phase split conditions. The results from supporting study which will cover solvent degradation and cleanup, and innovating new extractant, etc. are also included.
*; ; ; *
Journal of Nuclear Science and Technology, 19(5), p.410 - 418, 1982/00
Times Cited Count：2 Percentile：32.89(Nuclear Science & Technology)no abstracts in English
; ;
Nucl.Chem.Waste Manage., 3, p.23 - 28, 1982/00
no abstracts in English
; ;
JAERI-M 8864, 13 Pages, 1980/05
no abstracts in English
Yoshida, Kazuo; Tashiro, Shinsuke; Amano, Yuki; Yamane, Yuichi; Uchiyama, Gunzo; Abe, Hitoshi
no journal, ,
The experiments with simulated high level liquid waste (HLLW) have been carried out to obtain basic data about the behaviors of radioactive materials in an accident of evaporation to dryness by boiling of HLLW. The amount of ruthenium (Ru), which is one of key materials for public risk, volatized and transferred to vapor phase was measured in the experiments. Correlation equation of Ru transfer rate to vapor phase is proposed with parameters of temperature, nitric acid mole fraction and activity in HLLW.
Taniguchi, Takumi; Irisawa, Keita; Ito, Yuzuru; Namiki, Masahiro; Osugi, Takeshi; Abe, Tomohisa; Sato, Junya; Sakakibara, Tetsuro; Nakazawa, Osamu; Meguro, Yoshihiro; et al.
no journal, ,
no abstracts in English
Garc
a-Lodeiro, I.*; Lebon, R.*; Mahoney, D.*; Zhang, B.*; Irisawa, Keita; Osugi, Takeshi; Nakazawa, Osamu; Kinoshita, Hajime*
no journal, ,
Leaching tests have been conducted on CAC and CAP systems prepared with minimised water content, containing simulated secondary aqueous wastes to investigate their feasibility as wasteforms. In CAC, the effect of reduction in water content on leaching was small whereas CAP system indicated a significant benefit of reduction in water content. CAP appears to be beneficial to retain alkaline earth elements such as Sr, when cured at elevated temperatures.
