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Haga, Kazuko*; Shibuya, Kazutoshi*; Osugi, Takeshi; Yamada, Kazuo*
Haikibutsu Shigen Junkan Gakkai-Shi, 33(6), p.435 - 447, 2022/11
Cement solidification technology has been widely applied to waste stabilization and treatment because cement is not only relatively stable in physical and chemical properties after hardening, but also an inexpensive and easy-to-handle solidification material and treatment facilities are simple and economical. As the current status of cement solidification treatment technologies for wastes, this paper describes a study on cement solidification of wastes from the Fukushima Daiichi Nuclear Power Plant accident, the current status of cement solidification treatment of low-level radioactive wastes, and cement solidification technology for incinerated ash, and review previous research results on immobilization and leaching mechanisms of heavy metals in cement solidified products.
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
Times Cited Count：5 Percentile：36.98(Construction & Building Technology)Yamada, Kazuo*; Maruyama, Ippei*; Haga, Kazuko*; Igarashi, Go*; Aihara, Haruka; Tomita, Sayuri*; Kiran, R.*; Osawa, Norihisa*; Shibata, Atsuhiro; Shibuya, Kazutoshi*; et al.
Proceedings of International Waste Management Symposia 2021 (WM2021) (CD-ROM), 10 Pages, 2021/03
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
Sato, Isamu; Tanaka, Kosuke; Koyama, Shinichi; Matsushima, Kenichi*; Matsunaga, Junji*; Hirai, Mutsumi*; Endo, Hiroshi*; Haga, Kazuo*
Energy Procedia, 82, p.86 - 91, 2015/07
Times Cited Count：2 Percentile：17.42(Nuclear Science & Technology)Experiments simulating overheating conditions of fast reactor severe accidents have been previously carried out with irradiated fuels. For the present study, the chemical forms of the fission products (FPs) included in the irradiated fuels were evaluated by thermochemical equilibrium calculations. At temperatures of 2773 K and 2973 K, the most stable forms of Cs, I, Te, Sb, Pd and Ag are gaseous compounds. Cs and Sb detected in the thermal gradient tube (TGT) in the experiments can take gaseous chemical forms of elemental Cs, CsI, Cs
MoO
, CsO and elemental Sb, SbO, SbTe, respectively. By comparing experimental results and the estimations, it is seen CsI thermochemically behaves in a manner that traps it in the TGT, while elemental Cs trends to move as fine particles. The moving behavior of the gaseous FPs will obey not only thermochemical principles, but also those of particle dynamics.
Hino, Ryutaro; Yokomizo, Hideaki; Yamazaki, Yoshishige; Hasegawa, Kazuo; Suzuki, Hiromitsu; Soyama, Kazuhiko; Hayashi, Makoto*; Haga, Katsuhiro; Kaminaga, Masanori; Sudo, Yukio*; et al.
Nihon Kikai Gakkai-Shi, 107(1032), p.851 - 882, 2004/11
no abstracts in English
; Haga, Kazuo;
JNC TN4420 2002-001, 102 Pages, 2002/10
JNC-TN4420-2002-001.pdf:4.13MB
no abstracts in English
Haga, Kazuo; Hamada, Hirotsugu
Proceedings of 3rd International Conference on Nuclear Engineering (ICONE-3), 0 Pages, 1995/00
None
Nomura, Norio; Haga, Kazuo;
PNC TN9410 93-169, 71 Pages, 1993/10
Within a framework of transportable reactor study, a conceptual design study of power source has been performed for lunar base or space stations. Energy supply systems using Radioisotope fueled Thermoelectric Generators(RTGs) for extremely severe surroundings are introduced in this paper. At first, potential of RTGs for small-scale energy supply unit was researched from the point of theory, system structure, and performance. Also the manufacturing processes of radioisotopes to be used in RTGs were investigated. Secondly in order to make the nuclear energy system on the moon independent of the earth as much as possible, we proposed concepts of an investigation and mining method for uranium ore and continuous operation for nuclear fuel cycle which uses laser technology to reprocessing and group separation of elements as well as enrichment of uranium. Thirdly a Rankine cycle system sourced solar energy (Solar Ray System) was introduced. The power generating equipments of the system is the same as those of transportable reactor. Lastly we showed a concept of electrostatic power system sourced cosmic rays and a shielding method from cosmic rays.
; Haga, Kazuo
7th International Conference on Emerging Nuclear Energy Systems (ICENES '93), 0 Pages, 1993/09
None
Haga, Kazuo; Nomura, Norio; Otsubo, A.
7th International Conference on Emerging Nuclear Energy Systems (ICENES '93), 0 Pages, 1993/09
None
Nomura, Norio; Haga, Kazuo; ; Seino, Hiroshi;
PNC TN9410 93-154, 218 Pages, 1993/08
Within a framework of transportable reactor study, a conceptual design of power source to lunar base or space station has been performed. In this paper, structure and capability of compornents for a lunar base power plant are described. It is shown that SPECTRA-L is applicable to it. This is a 300kWe reactor, which needs no refueling during ten years operation. It is found that total weight is less than ten tons and the decay heat can be removed by natural circulation. The optimum construction method on lunar base is also proposed. A concept of a 3000kWe LUnar Base Activities Reactor (LUBAR) is also introduced. LUBAR is composed of one reactor unit and two generation units. The reactor section has three reactors. This plant can be operated for thirty years by changing the reactors. The optimized construction method is also proposed for this plant. The key technologies to realize these plants are described with the tentative R&D schedule.
; Haga, Kazuo
PNC TN9410 93-115, 75 Pages, 1993/04
[Objective] In order to miniaturize the transportable reactors studied at Frontier Advanced Reactor Group, a few modifications are added to the design concept of the reactor. In this report burning period calculations are performed to know the burning periods of the modified reactors. [Methods] The two dimensional transport and burning calculation code of TWODANT-BURN was used in the analysis. The core fuels were nitrides. The analysis was performed in the cases of nitrogen isotope components changed from those of natural nitrogen. The cores analysed are as follows. Core A : The core studied in 1991 for a deep sea reactor was used as a reference core. In order to miniaturize the core by decreasing the neutron leakage, the upper and lower ends of the radial reflectors were made 10 cm longer than those of the reference core. Core B : The gas plenum length of fuel pins were shortened, compared with that of the core A. Fuel volume was chosen to be 62.6%, that is, the maximum value from the point of geometry. Core C : The core moving upward and downward in a annular reglector. Continuous burning period was analysed. [Results] The results are as follows, Core A : Reactivity increased 20% from that of the reference core in the case of approapriate selection of fuel volume, 
U 95% enrichment and Pu content. The core A was about 21cm in diameter and height. Continuous burning period was about 10 years. Core B : The core B was about 21cm in diameter and height. Continuous burning period was about 10 years. Core C : Calculational results showed that the burning period of 2 years was technically possible for thermal output of 15 MWt.
; Haga, Kazuo
PNC TN9410 93-064, 66 Pages, 1993/02
[Objective]The objective of this report was concept construction of a fast reactor system for an unmanned deep sea base using a power source larger than 10 kWe, which is expected in the former half of a next century. [Method]Based on the studies performed until now, a compact system design was completed. The design used a NaK cooled fast reactor system as a primary circuit and He-Xe miture gas loops as secondary loops. Some studies were performed on the safety design, the operation method of the system, and the radiation damage of cables and paints. [Result]The system concept of the reactor and primary/secondary loops set in a pressure hull using two spheres of 2m 
was constructed. The safety design study was also satisfactory at the present stage of the study of the fast reactor system.
; Haga, Kazuo
PNC TN9410 93-006, 43 Pages, 1992/11
[Objective] To study hydrogen production methods using a high temperature fast reactor as its heat source. The hydrogen is expected to be clean energy source in the next century. [Method] Study was performed on a high temperature steam electrolysis method using a solid electrolyte, which is a hydrogen production method studied elsewhere. [Results] Assuming that hydrogen production system study was operated at 700 and 880
C of reactor vessel outlet coolant temperature of the HTFR, electrolysis efficiencies were determined to be 91.6 and 92.2 %, respectively. In this case, the electrolysis efficiency is shown as the following equation. Blectrolysis efficiency = (Heat generated by combution of produced hydrogen)/(Heat from HTFR + Electric power used for electrolysis) The system can also be operated at 550C with an additional heating system up to 900C. However technical feasibility of the heat exchangers used in the hydrogen production system is not clear.
Tamaoki, Tetsuo*; Sakai, Takuhiko*; Endo, Hiroshi*; Haga, Kazuo; Takahashi, Ryoichi*
Nuclear Technology, 99(1), p.58 - 69, 1992/07
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)None
; Haga, Kazuo; Sekiguchi, Nobutada
PNC TN9410 92-252, 62 Pages, 1992/05
[Objective] Study on the concept of a fast reactor gas turbine cogeneration system used near a small town, where there are not a large number of engineers, in a cold district distant from a large city. [Method] The population of the small town is supposed 200 to 2000 thousands. The study was performed on three kinds of plant systems, that is, 100, 50 and 10 MWe's. The design of a high temperature fast reactor previously studied for hydrogen production was used for a primary system. A closed Brayton cycle (CBC) was adopted for the secondary system to generate electric power. These plant systems have not the accident occurence possibility of sodium-water reaction since a steam turbine is not used for electric power generation. Water treatment is not necessary, too. In order that the gas turbine system has high thermal efficiency, the reactor vessel coolant outlet temperature is desirable to be high. Therefore the temperature was set to be 650 to 700C which is considered the highest temperature attained by steel and nickel alloy structural material. The temperature is higher than that of usual FBR's by 100 to 150C. Exhausted heat from the closed Brayton cycle is used for cogenration like district heating. [Result] The following plant systems were found to be possible from the conceptual design study on the above three kinds of power scale plants. [100 and 50MWe systems] Both systems adopted two loops for primary system. The former adopted four loops design and the latter two loops design for the secondary system, respectively. The reactor coolant temperature was 700C at the reactor outlets for both systems. An non-intercooling type compressor was used in the secondary system. The thermal efficiency of the CBC was about 24%. The scales of the building containing the secondary system were 31m in width, 40m in depth and 30m in height for the former and 31m in width, 22m in depth and 30m in height for the latter. [10MWe system] A ...
