Return Main Page

Presentation

Scientific Committee

Scientific Programme

Conference Secretariat

Instructions for Authors

Registration

Lodging

Exhibit & Workshop

 

Small Size Fast Reactor for Heat Supply, H2 Production and Desalination T. Sawada*, H. Endo�, H. Ninokata *Tokyo Institute of Technology, Res. Lab. Nucl. Reactors 2-12-1 O-okayama, Meguro-ku, Tokyo, Japan 152-8550 �Toshiba Corporation, Isogo Nuclear Engineering Center 8, Shinsugita-cho, Isogo-ku, Yokohama 235-8523, Japan For future reactors, it is strongly required that the energy generation cost is really competitive in the market. The target of the competitiveness is, for instance, combined-cycle gas turbine with the target value of the cost is ca. 2-3 �/kWh. The other aspect of energy required in near future is hydrogen. Hydrogen is regarded as clean, or green, with no toxic gas emission in the environment. As illustrated by the use of hydrogen for automobiles in the form of fuel cells, in the near future we may be confronted with the requirement of mass production of hydrogen. In such situation, nuclear power station can be a powerful tool to produce hydrogen. The third one is the application of nuclear energy or heat to desalinate sea water for the mass production of portable water . . � Repowering system: Historically speaking, the significance of repowering was first addressed by Battelle Memorial Institute. There is already a certain assessment of the implication of the combination with combined-cycle gas turbine (CCGT) with balance of plant (BOP) of nuclear power station1. Integrated Reactor Evaluation Program (IREP) has been used to eveluate the cost optimisation of the secondary circuit of a nuclear power station. In the simplified scheme of the secondary cooling circuit for IREP, the heat of the exhausted gas from the gas turbine is transferred to the steam generator outlet which results in a higher inlet temperature for high pressure steam turbine. This approach is newly named as dual-combined (DuCom) system2. The system gives higher thermal efficiency owing to the increased average temperature of the hot heat source. This concept can be also applied to the MPFR energy unit for improve the total thermal efficiency. . � Nuclear Hydrogen Production: It is generally understood that in near future we will have a variation of usage of hydrogen from transportation to daily living partially replacing current natural gas consumption. Though the price of hydrogen is rather expensive in the present hydrogen market, the hydrogen has prominent features such as easy storage and transportation compatibility and environmentally friendly characteristics so that it will not produce toxic gases like SOx nor greenhouse effect gas like CO2. Even though there is notation that the use of hydrogen burning can produce NOx, though the major use of hydrogen in future is that for fuel cells. So far there have been fund a number of processes to produce hydrogen from methane and water. The representative processes are: iodine-sulfur (IS) process that requires process temperatures of 800 to 900 oC 3, the four-step UT-3 thermochemical cycle with bromine-calcium-iron developed at the University of Tokyo 4, sorption enhanced reaction (SER) process that has been developed by Hufton, et al. 5, and Pd membrane reforming method developed by Tokyo Gas co. ltd. 6. The latter two methods seem rather promising because they require comparatively low teperature of process heat such as 450 - 600 oC. The SER process can perform a very high conversion ratio such as 80% with just one-step of chemical reactor, which results in lower cost. Thus it has preferable feature to fit the current design of sodium-cooled fast reactors. On the other hand, the Pd membrane reformer has also excellent capability to produce hydrogen by methane reforming. The cost, however, strongly depends on the price of palladium so that we cannot expect effective cost reduction by scaling up the membrane reformer. � NuclearDesalination: Generally speaking, the deployment of small and medium sized reactor is less attractive from the viewpoint of economy. The potential siting of small reactors are isolated areas with small grids such as islands and cities with desertification lands. To overcome the economical drawbacks of small reactors, it should be one realistic option to use the reactor both for the electricity generation and sea water desalination to produce portable water for daily life as well as greening the deserts. A reverse osmosis (RO) system is proposed for the desalination 7. The RO process requires the pressure of about 6 MPa to meat the osmotic pressure of the saline solution. For this condition, the turbine-driven pumps can be used, of which original function is to pump the feedwater back to the reactor with high pressure environment of ? 7 MPa. Tsikauri G., �CCGT+LWR = The power plant of the future?� Nuclear Engineering International, Oct. 1997. Kyung K.H. and Florido P.C., �Economics of Advanced LWR at SMR Power Range in Developing Countries,� Proc. of Internat. Seminar on Status and Prospects for Small and Medium Sized Reactors, Cairo, Egypt, 27-31 May, 2001 Shimizu S., Nakajima H., and Onuki K., �A Progress Report on Bench Scale Studies of the Iodine-Sulfur Process for Thermochemical Hydrogen Production,� Proc. TCM on High Temperature Applications of Nuclear Energy, IAEA-TECHDOC-761, 1994. Sakurai M., et al., �Nuclear Hydrogen Production by Adiabatic UT-3 Thermochemical Process,� Proc. 11th World Hydrogen Energy Conf., Stuttgart, FRG, 1996. Hufton J. and Waldron W., �Sorption Enhanced Reaction Process (SERP) for the Production of Hydrogen,� Proc. the 2000 Hydrogen Program Review, NREL/CP-570-28890, 2000. (in Japanese) Kataoka K. and Heki H, �A Distinctive Coupling Concept of Small Natural Circulation BWR and RO Desalination Ssytem,� Proc. of Internat. Seminar on Status and Prospects for Small and Medium Sized Reactors, Cairo, Egypt, 27-31 May, 2001