Evaluation of HLW glass dissolution/alteration kinetics by using micro-channel flow-through test method; Initial glass dissolution rate as a function of pH and temperature

Inagaki, Yaohiro*; Sakatani, Keiichi*; Yamamura, Yuki*; Mitsui, Seiichiro; Noshita, Kenji*; Miura, Yoshiyuki*; Kanehira, Norio*; Ochi, Eiji*; Mukunoki, Atsushi*; Chiba, Tamotsu*

Dai-7-Kai Saishori, Risaikuru Bukai Semina Tekisuto, p.136 - 137, 2011/01

Conventional static test methods are not appropriate to evaluate glass dissolution behavior at an arbitrarily-fixed condition due to compositional change of the solution with glass dissolution. In this study, we applied a newly-devised micro-channel flow-through test method to measurement of the initial dissolution rates of Japanese simulated waste glasses, JAEA-P0798 and JNFL-KMOC, at arbitrarily-fixed conditions and we evaluated temperature and pH dependence of glass dissolution. The results showed that the initial dissolution rate increased with temperature and had "V-shaped" pH dependence at each temperature.

Preliminary analysis for evolution of redox conditions in the near field

Chiba, Tamotsu*; Sasamoto, Hiroshi; Miki, Takahito*; Inagaki, Manabu*; Yui, Mikazu

JNC TN8400 99-027, 144 Pages, 1999/06

JNC-TN8400-99-027.pdf:19.19MB

It is planned that high level radioactive waste is going to be disposed under deep geological environment. It is believed that the chemical condition of deep groundwater is generally anoxic and reducing. However, during construction and operation phase of repository, oxygen will diffuse some distance into the surrounding rock mass, and diffused oxygen may remain in the surrounding rock mass even after repository closure. In such a case, the transitional redox condition around the drift is not preferable in view point of safety assessment for HLW disposal. Hence, it is very important to evaluate evolution of redox conditions in the near field. This report describes results of preliminary analysis for evolution of redox conditions in the near field rock mass and buffer after repository closure based on the model developed by Chiba et al. (1999). The results of preliminary analysis are summalized as follows : (1)The decrease of oxygen in the near field rock mass and buffer are affected by pH of groundwater and surface area of iron-bearing minerals. (2)The decrease of oxygen in the near field rock mass takes place at time scales lower than 500 years in considering the hypothetical reference groundwater pH range for H12 report. It is implicated that the redox conditions in the near field rock mass will recover to reducing conditions. (3)The decrease of oxygen in the buffer takes place at time scales lower several tens years under neutral to weakly alkaline pH values of porewater in the buffer, even if it is assumed that residual oxygen in the near field rock mass after repository closure will diffuse into the buffer. On the other hand, under weakly acid pH values of porewater in the buffer, it may be presumed that oxygen remain in the buffer at time scale more than 500 years.

None

; Chiba, Tamotsu*

PNC TJ1281 98-008, 35 Pages, 1998/02

PNC-TJ1281-98-008.pdf:0.91MB

None

Study both for migration in heterogeneous permeability/sorption field and for behavior of FP migration in near-field. Vol.II Behavior of FP migration in near-field

Ikeda, Takao*; Amaya, Takayuki*; Chiba, Tamotsu*

PNC TJ1281 97-004, 42 Pages, 1997/03

PNC-TJ1281-97-004.pdf:0.78MB

It is very important to explain the sorption mechanisms of relevant radionuclides, for the performance assessment of geological disposal and for the technical development of engineering barrier system. In the previous studies 1993-1996, these tests were carried out to understand sorption mechanism of SN; -solubility tests -sorption tests onto bentonite, pure montmorillonite, A-FEO(OH) -extraction tests from these minerals -sorption tests onto tuff as a next step, these tests were carried out ragarding SN in this study; -diffusion tests (in-diffusion) -tests for effect of SN concentration and ionic strength on sorption -sorption tests onto granite -tests for effect of coexistent ions on solubility

None

Ikeda, Takao*; ; Chiba, Tamotsu*

PNC TJ1281 97-002, 182 Pages, 1997/03

PNC-TJ1281-97-002.pdf:6.29MB

None

None

Chiba, Tamotsu*; Inagaki, Manabu*

PNC TJ1281 96-008, 46 Pages, 1996/03

PNC-TJ1281-96-008.pdf:2.57MB

None

Investigation and research on depth distribution in soil of radionuclides released by accident of Fukushima Daiichi Nuclear Power Station, TEPCO, 3; Distribution coefficients of Cs and I onto soil

Tanaka, Shingo; Sato, Haruo; Niizato, Tadafumi; Amano, Kenji; Nohara, Tsuyoshi; Iwatsuki, Teruki; Murakami, Hiroaki; Sugita, Yutaka; Nakayama, Masashi; Abe, Hironobu; et al.

no journal, , 

The sorption distribution coefficients of cesium and iodine onto the soil are studied. The batch sorption experiments were conducted onto the 24 specimens obtained from 11 sites (12 geoslicers) at each two different depth compartment. The experiments were based on the way standardized by Atomic Energy Society of Japan. The Kd values of cesium ranged from 1,000 to 100,000 ml/g, corresponding to the result that most of the cesium in the investigation sites are stayed in the surface of the ground. On the other hand, the Kd values of iodine ranged from 0.4 to 150 ml/g. It is likely that the difference of Kd values is affected by not only the chemical form of the elements between cesium and iodine, but also mineral composition, cation and anion exchange capacities, content of organic matter, and so on. This investigation initially focuses on varieties of soil, such as sandy or clayey soil, and soil colors.

Study on an approach to assess the effect of seismicity/fault movement for groundwater scenarios of a geological disposal concept in a sedimentary rock

Ebashi, Takeshi; Kawamura, Makoto; Inagaki, Manabu; Shibata, Masahiro; Chiba, Tamotsu*

no journal, , 

no abstracts in English