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JAEA Reports

Development of denitration technique for MA-type bituminized waste product by aqueous leaching method

Irisawa, Keita; Komatsuzaki, Toshio; Kawato, Yoshimi; Sakakibara, Tetsuro; Nakazawa, Osamu; Meguro, Yoshihiro

JAEA-Technology 2015-008, 28 Pages, 2015/03

JAEA-Technology-2015-008.pdf:13.63MB

In JAEA, 16,671 drums of intermediate-radioactive bituminized waste products (BWPs) have been stored in asphalt solidification storages. As a way of reduction of uncertainty in assessment of disposal of the BWPs, a processing technique of separation of nitrate salts from the BWP by means of an aqueous leaching method was studied. As elemental techniques for the denitration process, (1) crushing techniques of a BWP and (2) denitration techniques for the crushed BWP by the aqueous leaching method were investigated. In order to promote leaching amounts of nitrates, the BWP was crushed, and the grain size distribution was investigated by sieving. Moreover, leaching behaviors of nitrate, nitrite and elements as radionuclides including in the BWP were investigated.

JAEA Reports

User's guide of cement solidification test for incinerated ash

Nakayama, Takuya; Kawato, Yoshimi; Osugi, Takeshi; Shimazaki, Takejiro; Hanada, Keiji; Suzuki, Shinji; Sakakibara, Tetsuro; Nakazawa, Osamu; Meguro, Yoshihiro

JAEA-Technology 2014-046, 56 Pages, 2015/03

JAEA-Technology-2014-046.pdf:7.61MB

The combustible and flame-retardant radioactive wastes generated as a result of the research activities in Japan Atomic Energy Agency (JAEA) are incinerating to reduce their volume. The incinerated ash is planned to be solidified using cement for disposal. Since the properties of ashes generated in each institute of JAEA are varied with the type of incinerator and the wastes to be incinerated, it is necessary to do fundamental solidification tests in each institute to decide operating conditions of the planning cement solidification facility. It is important to standardize evaluating methods of cement and solidified waste because some characters depend on measuring method. This user's guide have been prepared how to decide the cement solidifying conditions of ash to design the cement solidification facility in JAEA. Requirements on the regulations of solidified radioactive waste have been examined and seven technical criteria, e.g. compressive strength, fluidity, have been selected as characters to be evaluated. Some empirical notes about selection of cement, admixtures, procedure on making a test piece, evaluation of expanding, compressive strength, solubility have been described. The strategy of tests and tips for finding optimized solidification condition has been summarized. Finally the example of optimized conditions satisfied the requirements and some problems to be solved have been described.

JAEA Reports

Development of refilling techniques of LA-type bituminized waste products

Irisawa, Keita; Komatsuzaki, Toshio; Kawato, Yoshimi; Sakakibara, Tetsuro; Nakazawa, Osamu; Meguro, Yoshihiro

JAEA-Technology 2014-039, 28 Pages, 2014/12

JAEA-Technology-2014-039.pdf:6.13MB

In JAEA, 13,296 drums of low-radioactivity bituminized waste products (BWPs) have been stored in asphalt solidification storages. In order to effectively utilize the space of the BWP in a repository site, we studied refilling techniques of the BWP from the drum to a box-shaped container. Tentative processes, which we devised, consisted of (1) take-off of BWP from the drum, (2) separation of a post filling part from BWP and (3) filling of BWP to a box-shaped container. Two methods for each process were selected, and work efficiencies of the methods were investigated by using a synthetic BWP.

Journal Articles

Expansion control for cementation of incinerated ash

Nakayama, Takuya; Suzuki, Shinji; Hanada, Keiji; Tomioka, Osamu; Sato, Junya; Irisawa, Keita; Kato, Jun; Kawato, Yoshimi; Meguro, Yoshihiro

Proceedings of 2nd International Symposium on Cement-based Materials for Nuclear Wastes (NUWCEM 2014) (CD-ROM), 12 Pages, 2014/06

JAEA Reports

Cement solidification test for incinerated ash, 1; Fundamental solidification characteristics of incinerated ashes

Kawato, Yoshimi; Tomioka, Osamu; Takahashi, Kuniaki; Meguro, Yoshihiro; Sakamoto, Hiroyuki*; Haga, Kazuko*

JAEA-Technology 2010-013, 38 Pages, 2010/07

JAEA-Technology-2010-013.pdf:1.36MB

It is important to understand fundamental solidification characteristics of incinerated ashes of combustible and poorly combustible wastes generated by JAEA. Simulated solidified substances using incinerator fly ash were prepared under different conditions such as solidified materials, ash filling rates, amount of solidification retarders and so on. The compressive strength of the solidified substances prepared using a normal portland cement (OPC), a blast furnace slag cement (BB), and a low alkalinity cement (LAC) exceeded a standard value, 1.47 N/mm$$^2$$. The compressive strength made from the BB was lower 1.47 N/mm$$^2$$ when the filling rate of the incinerated ash was 40%. For the substances using the LAC, all the strengths were over 1.47 N/mm$$^2$$. Pb and Zn would behave as retardative substances for solidification. All substances showed the compressive strength with the BB or the LAC. As insolubilizers for heavy metals, ferrous sulfate and sodium sulfide prevented Cr from elution.

JAEA Reports

Study on transportation of low level waste package for disposal

Takahashi, Kuniaki; Kawato, Yoshimi; Hanada, Keiji

JAEA-Review 2009-010, 37 Pages, 2009/07

JAEA-Review-2009-010.pdf:2.39MB

Regulatory matters for transportation of radioactive waste, legislation, regulations and standards, are checked. We have conducted a study on cost and transportation measure for waste packages from Tokai reprocessing plant and MOX fuel fabrication facilities in Nuclear Fuel Cycle Engineering Laboratories. Here, the number, radioactive inventory and properties of the waste packages are quoted from the second progress report on research and development for TRU waste disposal in Japan. We sorted out the waste packages by the type of packages based on the legislation for transportation of radioactive material. We have studied the packaging for each type of package, and have estimated number of the packages of a conveyance, number of conveyances for transportation of all waste packages. As a result, the waste packages constitutes ca.86% of Industrial package Type 2, ca.2% of Type A package and ca.12% of Type B package. Number of transport by sea for the waste packages is estimated as about 120 times.

JAEA Reports

Experiments of sodium nitrate liquid waste treatment by biological method

Takahashi, Kuniaki; Meguro, Yoshihiro; Kawato, Yoshimi; Kuroda, Kazuhiko*; Ogawa, Naoki*

JAEA-Technology 2008-084, 12 Pages, 2009/02

JAEA-Technology-2008-084.pdf:1.06MB

Low level liquid waste discharged from a Reprocessing Facility includes sodium nitrate. In the case that it is directly solidified with cement and so on and then the solidified waste are disposed under the ground, sodium nitrate soaks into the environment through underground water layer. We planned to apply the biological treatment system that many ordinary industrial plants are running in the field of waste water treatment to reduce nitrate. We carried out degradation experiments of nitrate for 4wt% sodium nitrate solution by biological method. To solve the assignments that biological treatment technology has, we tested and obtained the results as shown below; (1) The amount of sludge ash could be cut down a tenth as much as usual. The disposal cost reduction of secondary waste is just in sight. (2) Treatment performance could be improved up to 7 kg-N/m$$^{3}$$/d from 4 kg-N/m$$^{3}$$/d. It could be expected the more compact system by improvement of the membrane set into the biological treatment tanks.

Oral presentation

Development of sodium nitrate waste fluid treatment technology by biological method

Takahashi, Kuniaki; Meguro, Yoshihiro; Kawato, Yoshimi; Shibata, Katsushi*

no journal, , 

Low level liquid waste discharged from Tokai Reprocessing Plant includes high concentration of sodium nitrate. In the case that the solidified waste are disposed under the ground, leached nitrate migrates into the environment and impacts on surround. To avoid this impact, we planned to apply the biological treatment system to reduce nitrate from this waste liquid. To solve the assignments that biological treatment technology has, we tested and obtained the results as shown below; (1) The amount of sludge ash could be cut down a tenth as much as usual. The disposal cost reduction of waste is just in sight. (2) Treatment performance could be improved up to 7 kg-N/m$$^{3}$$/d from 4 kg-N/m$$^{3}$$/d. It could be expected the more compact system by improvement of the membrane set into the biological treatment tanks.

Oral presentation

Development of biological treatment of high concentration sodium nitrate waste liquid

Takahashi, Kuniaki; Meguro, Yoshihiro; Kawato, Yoshimi; Ogawa, Naoki*; Kuroda, Kazuhiko*; Shibata, Katsushi*

no journal, , 

An electrolytic reduction, chemical reduction, and biological reduction have been picked up as a method of nitrate liquid waste treatment system exhausted from the reprocessing. As a result of comparing them, it was shown that the biological treatment was the most excellent method in safety and the economy.

Oral presentation

Study of cement solidification for incinerated ash, 1; Stabilization of heavy metals in cement solidified material

Tomioka, Osamu; Kawato, Yoshimi; Meguro, Yoshihiro; Haga, Kazuko*; Sakamoto, Hiroyuki*

no journal, , 

no abstracts in English

Oral presentation

Study of cement solidification for incinerated ash, 2; Heavy metal stabilizing mechanisms

Haga, Kazuko*; Sakamoto, Hiroyuki*; Tomioka, Osamu; Kawato, Yoshimi; Meguro, Yoshihiro

no journal, , 

no abstracts in English

Oral presentation

Hydrogen gas generation from cement solidified form by $$gamma$$-ray irradiation

Nakayama, Takuya; Kawato, Yoshimi; Meguro, Yoshihiro

no journal, , 

Radioactive combustible wastes generated in JAEA are incinerated and the incinerated ash obtained will be solidified with cement. Hydrogen gas may be generated from the cement solidified form by radiolysis. Therefore, we tried to determine G-value for hydrogen gas generation from the cement solidified form. The G-value is needed to evaluate safety of storage of the cement solidified form. An artificial cement solidified form of incinerated ash was irradiated with 2.7 kGy $$gamma$$-ray from a $$^{60}$$Co source for 1 hour. G-value calculated using the absorbed dose, the weight of the form and the amount of hydrogen generated was 1.22 $$pm$$ 0.18 molecule/100 eV.

Oral presentation

Study of cement solidification using incinerated ash, 3; Properties of cement solidified products with various incinerated ashes

Nakayama, Takuya; Suzuki, Shinji; Kawato, Yoshimi; Meguro, Yoshihiro

no journal, , 

Incinerated ashes differ in composition or characteristics for types of incinerator and the subject of incineration. Thus, we made solidified cement forms with various kinds of ashes for determine the kneading condition and solidified characteristics. As a result, we found that fluidity, compressive strength and hardening time were differing greatly for kinds of incinerated ashes.

Oral presentation

Study for cement solidified of incinerated ash of agricultural products, etc.

Nakayama, Takuya; Kawato, Yoshimi; Meguro, Yoshihiro

no journal, , 

no abstracts in English

Oral presentation

Study of conditioning technologies of secondary wastes produced from contaminated water treatment, 1; Cement solidification of sludge from coagulating sedimentation device

Sugaya, Atsushi; Horiguchi, Kenichi; Akutsu, Shigeru; Sato, Junya; Nakayama, Takuya; Kawato, Yoshimi; Meguro, Yoshihiro

no journal, , 

Cement solidification of sludge produced from contaminated water treatment by a coagulating sedimentation device was studied. Effect of water-to-cement ratio, loading rate, and components in the sludge on curing was investigated using simulated sludge. We have performed R&D work to apply cement solidification to the sludge and evaluated characteristics of solidification process with an eye towards the disposal as a basic study of waste treatment technology to prepare for the case if the sludge storage ability is not completely under safe conditions based on the results of long-term storage measure study. The results from these studies demonstrate that the simulated sludge can be successfully encapsulated by ordinary cement. We will investigate an allowance against variation of sludge constituents and characteristics and study a dissolution behavior of cesium and hazardous component from the waste form in the future.

Oral presentation

Study of cement solidification using incinerated ash, 4; Properties of cement solidified form of incinerated ash in Fugen

Nakayama, Takuya; Suzuki, Shinji; Kawato, Yoshimi; Meguro, Yoshihiro

no journal, , 

Fugen incinerated ash which is radioactive waste was researched about kneading characteristics and solidification behavior. As a result, fluidity was improved by adding water reducing admixture. Solidification form with bottom ash had slow hardening and expansion.

Oral presentation

Hydrogen gas generation from cement solidified form by $$gamma$$-ray irradiation, 2

Nakayama, Takuya; Kawato, Yoshimi; Suzuki, Shinji; Meguro, Yoshihiro

no journal, , 

no abstracts in English

Oral presentation

Study of conditioning technologies of secondary wastes produced from contaminated water treatment,3; Properties of waste form of simulated sludge with inorganic solidified materials

Sato, Junya; Nakayama, Takuya; Suzuki, Shinji; Tomioka, Osamu; Kawato, Yoshimi; Sugaya, Atsushi; Horiguchi, Kenichi; Akutsu, Shigeru; Meguro, Yoshihiro

no journal, , 

no abstracts in English

Oral presentation

Study of conditioning technologies of secondary wastes produced from contaminated water treatment, 2; Conditioning tests of simulated sludge with inorganic solidified materials

Nakayama, Takuya; Sato, Junya; Suzuki, Shinji; Tomioka, Osamu; Kawato, Yoshimi; Sugaya, Atsushi; Horiguchi, Kenichi; Akutsu, Shigeru; Meguro, Yoshihiro

no journal, , 

no abstracts in English

Oral presentation

Study of cement solidification using incinerated ash, 5; Hydrogen gas generation by radiolysis

Nakayama, Takuya; Suzuki, Shinji; Hanada, Keiji; Kawato, Yoshimi; Meguro, Yoshihiro

no journal, , 

no abstracts in English

22 (Records 1-20 displayed on this page)