Data on migration analysis for TRU waste disposal; Results of plutonium solubility experiments in porewater of cement hydrates

Suguro, Toshiyasu; Nishikawa, Yoshiaki*; Watahiki, Takashi*; Kagawa, Akio

JAEA-Technology 2013-023, 22 Pages, 2013/10

JAEA-Technology-2013-023.pdf:2.41MB

For safety assessment of TRU waste disposal, solubility of plutonium was investigated under hardened cement paste porewater condition. Polycarboxylic acid compound, which have the possibility to be used for the TRU waste disposal, was selected as the cement admixture for the experiment. Initial concentration of Pu was 10 M in the experiment. The porewater of hardened cement paste was obtained by squeezing out the kneading of ordinary portland cement and deionized water with the cement admixture. The porewater of hardened cement paste without cement admixture is also used for the experiment. The maximum experimental period was 154 days. The experiment was carried out at room temperature (298 5 K) under argon atmosphere, in which oxygen concentration was lower than 1 ppm. Pu concentration in the porewater of hardened cement paste with or without the cement admixture were in the order of 10 mol/dm after 154 days. This value is comparable to the solubility of Pu(IV) under high pH condition, suggesting that the solubility of Pu was not affected by the cement admixture in hardened cement paste.

Data on plutonium sorption onto rock; Results of the experiment for data on plutonium sorption onto tuff under conditions of reducing and of presence of nitrate

Suguro, Toshiyasu; Nishikawa, Yoshiaki*; Komuro, Takashi*; Kagawa, Akio; Kashiwazaki, Hiroshi; Yamada, Kazuo

JAEA-Technology 2007-058, 20 Pages, 2007/11

JAEA-Technology-2007-058.pdf:3.26MB

For safety assessment of TRU waste disposal, data on sorption data of plutonium on Tuff have been obtained by a static batch-type experiment. Because the repository condition will be reducing and be affected by considerable amount of nitrate in waste, the authors carried out the experiments using Tuff under the reducing (NaSO as added as reductant) and anoxic condition (O1 ppm) and solution of 0 to 0.5 M NaNO. The experimental results suggest that distribution coefficient (Kd) ranges 0.2 to 0.7 m kg in case of L/S=0.1 m kg. Similarly the Kd ranges, 1 to 7 m kg at L/S=1 m kg. However, almost samples of the solution after experiments were plutonium solubility less than detection limit(10mol/dm) of alpha spectrometer. The reason, it is guessed plutonium coprecipitation with calcium hydroxide, because experiments using saturated calcium hydroxide in the liquid.

Promising Fast Reactor Systems in the Feasibility Study on Commercialized FR Cycle Systems

Sakamoto, Yoshihiko; Sakamoto, Yoshihiko; Enuma, Yasuhiro; Ando, Masato; Nishikawa, Akira; Kotake, Shoji; Ieda, Yoshiaki

Dai-14-Kai Kantaiheiyo Genshiryoku Kaigi (2004-Nen 3-Gatsu 21-Nichi25-Nichi), 0 Pages, 2003/00

This paper describes the summary of an interim report of phase II of the Feasibility Study on Commercialized FR Cycle Systems, related to reactor systems. Promising plant concepts (sodium-, lead-bismuth-, helium-, and water-cooled fast reactor) and reactor core concepts are presented. These concepts are quantitatively evaluated from the viewpoint of the suitability to the development targets, such as economic competitiveness, efficient utilization of resources and reduction of environmental burden, with securing safety. As results, sodium cooled fast reactor is well suited to the development targets. LBE cooled fast rector would have a potential to attain the development targets. Helium gas cooled fast reactor would have the great potential for high thermal efficiency and multipurpose energy system. And water cooled fast reactor has the advantage that there are many experiences with LWR. Furthermore the crucial issues for technical feasibility are also clarified as road map of key technology development for each concept.

Alkali hydrolysis experiment of organic materials such as cement additives

Fukumoto, Masahiro; Nishikawa, Yoshiaki*

JNC TN8400 2001-017, 355 Pages, 2001/03

JNC-TN8400-2001-017.pdf:6.43MB

The alkali hydrolysis experiments which seem to be important from the view point of the alteration mechanism using the following seven organic materials was performed as a part of the evaluation of the influence on the disposal of the organic materials contained in the TRU wastes. As a result of the alkali hydrolysis experiments (90C and 91d), each organic materials became those of lower molecular weight. The degradation products were able to be detected in the solution. The organic materials seem to be degraded to the organic matters which were confirmed in this study in a long term of disposal. The degradation products were shown below. Therefore, the evaluation of the influence on the migration of radionuclides by degradation products becomes important in the future. (1)Cement additives of Naphthalenesulfonic acid and Ligninsulfonic acid ( Naphthalenedisulfonic acid etc.) (2)Cement additives of polycarboxylic acid ( Oligomer of distal methoxypoly ethylene glycol.) (3)Ethylenediamine-N,N,N',N'-tetraacetic acid disodium salt ( Acetic acid desorped and cyclized organic matters from EDTA.) (4)Tributyl phosphate ( Dibutyl phthalate, n-butanol) (5)Poly vinyl acetate ( Acetic acid) (6)Nylon66 ( Adipic acid, Hexamethylenediamine) (7)Cured epoxy resin ( Glycerol poly glycidyl ether, Carboxylic acid)

Distribution coefficients measurement experiment of americium to Ca-bentonite with cement additives

; Nishikawa, Yoshiaki*; Kagawa, Akio;

JNC TN8400 2000-017, 30 Pages, 2000/03

JNC-TN8400-2000-017.pdf:1.97MB

The influence of the cement additives on the distribution coefficients of americium-241 to the Ca-bentonite was confirmed. The adsorption experiment of americium-241 to Ca-bentonite with cement additives was performed by the batch method, as a part of the influence evaluation of the organic in the research of TRU waste disposal. As a result, the distribution coefficient of americium-241 to the Ca-bentonite was over 1.2E+3m/kg in the condition of the absence of cement additives. In the case of low concentration (0.3g/kg) of the naphthalenesulfonic acid type cement additives, the distribution coefficient was 5.2E+2mkg. And, in the case of high concentration (30g/kg) of the same cement additives, the distribution coefficients was 2.0E-1m/kg. On the other hand in the case of flow concentration (0.5g/kg) of the polycarboxylic acid type cement additives, the distribution coefficients was over 1.3E+3m/kg. And, in the case of high concentration (50g/kg) of the same cement additives, the distribution coefficient was 1.8E-1m/kg. Here, selected cement additives concentrations were based on a standard concentration of 10g/kg when the ratio of water:cement is about one. From these results, the distribution coefficient of americium-241 to the Ca-bentonite decreases according cement additive concentration. The distribution coefficients were similar on different kinds of cement additives. The cement additives concentration influences the distribution coefficient. The distribution coefficient was small in the case of high concentration of the cement additives. That is, it is thought that the cement additives have small influences on the distribution coefficient of americium-241 to the Ca-bentonite in the case of low concentration, though the cement additives have influences on the distribution coefficient of americium-241 to the Ca-bentonite in the case of high concentration.

None

Shibutani, Tomoki; Nishikawa, Yoshiaki*; Inui, Shinichi*; Uchidate, Nobuyuki*; Yui, Mikazu

PNC TN8410 94-395, 41 Pages, 1994/10

PNC-TN8410-94-395.pdf:1.01MB

None

Solubility of actinide ions in cement pore water, 1; Effect of super plasticizer on solubility of plutonium

Suguro, Toshiyasu; Kagawa, Akio; Nishikawa, Yoshiaki*; Watahiki, Takashi*; Mihara, Morihiro; Iijima, Kazuki

no journal, , 

no abstracts in English