General overview of the research project investigating the radionuclide solution behavior in mock mortar matrix modeled after conditions at the Fukushima-Daiichi Nuclear Power Station

Igarashi, Go*; Haga, Kazuko*; Yamada, Kazuo*; Aihara, Haruka; Shibata, Atsuhiro; Koma, Yoshikazu; Maruyama, Ippei*

Journal of Advanced Concrete Technology, 19(9), p.950 - 976, 2021/09

https://doi.org/10.3151/jact.19.950

New project on the analysis of contamination mechanisms of concrete at the Fukushima Daiichi Nuclear Power Station

Yamada, Kazuo*; Maruyama, Ippei*; Koma, Yoshikazu; Haga, Kazuko*; Igarashi, Go*; Shibuya, Kazutoshi*; Aihara, Haruka

Proceedings of International Waste Management Symposia 2019 (WM2019) (CD-ROM), 6 Pages, 2019/03

The Evaluation of Solidifying Performance of Heavy Metal Waste Using Cementitious Materials (2)

Fujita, Hideki*; Harasawa, Shuichi*

JNC TJ8410 2005-005, 103 Pages, 2005/02

JNC-TJ8410-2005-005.pdf:0.75MB

Some of radioactive waste generated from JNC's facilities contain the poisonous substances such as lead and mercury. In order to establish an appropriate method of the treatment of these heavy metals, solidification performance was evaluated using cementitious materials. The results are summarized below:1. The test of stabilization process of mercuryThe conversion process from mercury to the powdery mercury sulfide(red) was examined. It was confirmed that the conversion was possible using the liquid phase reaction at 80C by the addition of sulfur powder with the NaOH solution. 2. The fabrication and evaluation of solidified wastes (1) solidification test of the lead wasteAs for the elution ratio of lead, it had obtained the better result (0.06 mg/L) at the case of solidification of sulfide lead 30mass% packed in the total solidified waste by using Highly Fly-ash contained Silicafume Cement (HFSC) than standard value(0.3mg/L) at Regulations of Waste Management and Public Cleansing Law. Additionally, it was confirmed the using admixture of the inorganic reducing agent such as the Iron (II) chloride tetrahydrate deceased the elution ratio of lead to the under limit of measurement (0.01 mg/L) at the case of solidification of sulfide lead 30 mass% packed in the total solidified waste by using Low Alkalinity Cement contained calcium sulpho-aluminate (LAC). (2)solidification test of the mercury waste Four types of solidified waste were fabricated with different binder. It was confirmed one-axis compressive strength for all solidified waste to pass the technical standards 15kg/cm2 (1.5 Mpa) for homogeneously solidified waste as the Low-level Radioactive Waste Disposal Center in Aomori Prefecture, and the elution ratio of mercury, it had obtained the result for all solidified waste to pass the standard value (0.005 mg/L) at Regulations of Waste Management and Public Cleansing Law.

Study on the Alteration of Hydrogeological and Mechanical Properties of the Cementitious Material (III); Summary Report

Takei, Akihiko*; Fujita, Hideki*; Harasawa, Shuichi*

JNC TJ8400 2004-025, 79 Pages, 2004/02

JNC-TJ8400-2004-025.pdf:5.79MB

We experimentally investigated the influence of several phenomena at the disposal environment, to evaluate the long-term alteration of cementitious material. The results are shown below. (1)Hardened cement paste specimens were altered and characterized after artificial seawater permeation. The calcium dissolution was accelerated, and secondary minerals containing magnesium were deposited. The permeability became one to three orders of magnitude smaller than data from specimens altered by deionized water permeation. It was estimated that secondary mineral formations reduced the permeability. These results meant that seawater and pure water differ remarkably from each other in influence to alteration of cementitious material. (2)Two type mixture proportions concrete, two type mixture proportions mortar and a cement paste under same W/C ratio 55% were characterized, to apply the accumulated data of paste to concrete or mortar. Compressive strength of paste was lower than that of concrete and mortar. It was contrary to the previous report. The behavior of Young's modulus and Poisson's ratio could be explained well using amount of aggregate. The data of permeability meant that boundary between aggregate and cement paste didn't become path of water flow, and that aggregate disturbed permeation. (3)Self-sealing property of cracked specimen of cementitious material were investigated by the water permeation test using sodium bicarbonate solution. The permeability decreased in two orders of magnitude, and possibility of sealing was suggested. By the morphology, the deposits in the cracks might be portlandite and C-S-H, and be not calcium carbonate. (4)Alteration of characteristics of cementitious material in sodium-nitrate and ammonia solution was evaluated by the water permeation test. Alteration degree of the nitrate and ammonia solution case showed similar trend to that of the sodium nitrate solution case. This result meant that ammonia solution would not ...

Study on the Alteration of Hydrogeological and Mechanical Properties of the Cementitious Material II

Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*; Hibiya, Keisuke*; Yokozeki, Kosuke*; Watanabe, Kenzo*

JNC TJ8400 2003-047, 120 Pages, 2003/02

JNC-TJ8400-2003-047.pdf:4.46MB

We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or immersing as the fundamental data.

The Effect of Nitrates on the Alteration of the Cementitious Material II

Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*

JNC TJ8400 2003-042, 67 Pages, 2003/02

JNC-TJ8400-2003-042.pdf:4.7MB

TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. In this study, we estimated the influence of sodium nitrate and also that of the chemical compounds derived from the sodium nitrate to the degradation of the cementitious material. 1) Evaluation of the influence of nitrate ion on the alteration of the cementitious material Alteration of characteristics of cementitious material was evaluated by the water permeation test using sodium nitrate solution. The calcium concentration of sodium nitrate solution permeated sample was higher than that of blank. The result indicates that sodium nitrate solution will accelerate the alteration of cementitious material. the permeation test was continued by using the ion-exchanged water as the permeation-water. As the results, the chemical and physical characteristics of the samples approached to those of blanks.2) Evaluation of the influence of ammonia on the alteration of the cementitious material Alteration of characteristics of cementitious material in nitrate and ammonia solution was evaluated by the water permeation test using 1mol/liter-sodium-nitrate and 0.5mol/liter-ammonia solution (denoted as NH-solution in the following). The calcium concentration of NH-solution permeated sample was higher than that of blank and the value of the calcium concentration was almost the same as that of the sodium nitrate solution case. The alteration range by the calcium leaching of the solid phase of the NH-solution case shows similar trend to that of the sodium nitrate solution case. The acceleration of the calcium dissolution was considered from this result. And the change of the water-permeability indicated the same trend with sodium-nitrate-solution case. From these results we confirmed that ammonia solution would not influence the alteration of cementitious solution.

None

; *; Owada, Hitoshi*; *; *

JNC TJ6420 2002-007, 28 Pages, 2002/03

JNC-TJ6420-2002-007.pdf:0.38MB

None

The effect of nitrates on the alteration of the Cementitious Material

*; Owada, Hitoshi*; Fujita, Hideki*; *

JNC TJ8400 2002-033, 60 Pages, 2002/02

JNC-TJ8400-2002-033.pdf:1.97MB

TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. Since the temperature of the deep-underground is higher than that of the near surface and a part of the TRU waste generates the heat accompanied with the decay of the radioactive nuclides, the influences of the heat to the barrier material also should be taken into account. In this study, we estimated the influence of sodium nitrate and also that of the leachate from the ROBE-waste (borate-solidified body of concentrated low-level liquid waste) to the degradation of the cementitious material. We also obtained the mineralogical data of cementitious mineral after alteration in elevated temperature conditions. Results in this year are described below. (1)Alteration of characteristics of cementitious material in nitrate solution were evaluated by the water permeation test using sodium nitrate solution. The enhancement of the alteration of cementitious material due to sodium nitrate was observed. The dissolution quantity of the calcium of sodium nitrate solution permeated sample was larger than that of deionized water permeated sample (denoted as "blank" in following). Hydraulic conductivity of sodium nitrate solution permeated sample was lower than blank, but after changing permeation liquid from sodium nitrate solution to deionized water, hydraulic conductivity rose quickly. The increase of porosity and the decrease of compressive strength were observed in the case of sodium nitrate solution compared with blank. In the nitrate solution, sulfate type and carbonate type of AFm changed into the nitrate type AFm. The nitrate type AFm altered to the carbonate type AFm when the nitrate concentration was lowered. (2)The influence of the leachate from the two types of ROBE-waste on the dissolution of the cementitious material was evaluated by the leaching experiments. Dissolution of the calcium from the ...

None

; *; Owada, Hitoshi*; *; *

JNC TJ6430 2002-002, 38 Pages, 2002/02

JNC-TJ6430-2002-002.pdf:2.33MB

None

Research and development on preceding processing methods for contaminated water management waste at Fukushima Daiichi Nuclear Power Station, 5; Gamma-ray irradiation test on solidified body of cement and Alkali Activated Material

Taniguchi, Takumi; Imaizumi, Ken*; Namiki, Masahiro*; Osugi, Takeshi; Kuroki, Ryoichiro; Kikuchi, Michio*; Yamamoto, Takeshi*; Kaneda, Yoshihisa*; Haga, Kazuko*

no journal, , 

It is important to understand fundamental solidification characteristics of contaminated water management waste at Fukushima Daiichi Nuclear Power Station. The Solidified bodies are fabricated with cementitious material and Alkali Activated Material, and are irradiated with Gamma-ray.