Jin Iwatsuki

Development of Hydrogen Production Technology by Thermochemical Water Splitting IS Process Pilot Test Plan

Japan Atomic Energy Agency (JAEA) has been conducting a study on a thermochemical IS process for hydrogen production. A pilot test of IS process is under planning that covers four R&D subjects: (1) construction of a pilot test plant made of industrial materials and completion of a hydrogen production test using electrically-heated helium gas as the process heat supplier, (2) development of an analytical code system, (3) component tests to assist the hydrogen production test and also to improve the process performance for the commercial plant, (4) a design study of HTTR-IS system. Development of innovative chemical reactors is in progress, which are equipped with a ceramic heat exchanger. In the design of the IS plant, it is important to establish the system for “design by analysis”. Therefore, we have developed a multiphase flow analysis code that can analyze systems in which chemical reactions occur.

Counter-permeation of deuterium and hydrogen through INCONEL 600®

Abstract Permeation of hydrogen isotopes through a high-temperature alloy used for heat exchanger and catalyst pipes is an important problem in the hydrogen production system connected to the High-Temperature Engineering Test Reactor (HTTR). The objective of this study is to investigate the effect of the existence of hydrogen in an outside pipe on the amount of permeated deuterium through the pipe. It was found that the amount of permeated deuterium decreases by increasing the partial pressure of hydrogen in the outside pipe when the partial pressure of deuterium in the pipe is lower than 100 Pa and that of hydrogen in the outside pipe is larger than 10 kPa. The amount of permeated deuterium on counter permeation was predicted quantitatively by using an effectiveness factor for diffusivity of deuterium in metals and by taking into account the equilibrium state for hydrogen, deuterium, and HD molecules on the metal surface. From the results obtained in this study, it is supposed that the amount of tritium transferred from the primary circuit of the HTTR to the hydrogen production system will be reduced by the existence of high-pressure hydrogen in the catalyst pipe of the steam reformer.

Investigation on Iodine Release Behavior During the Operation of High Temperature Engineering Test Reactor (HTTR)

Japan Atomic Energy Agency (JAEA) has planned to investigate on iodine release behavior from fuel through the testing operation of High Temperature Engineering Test Reactor (HTTR) in order to contribute to the reasonable estimation of the radiation exposure necessary for the realization of HTGR in the future. In this test, the fractional release of iodine will be measured and evaluated by measuring xenon isotopes, the daughter nuclides of iodine isotopes, in the primary coolant sampling under the loss-of-forced cooling (LOFC) test by which the primary coolant circulator is shut down and/or the manual scram test of HTTR. In parallel, the local area of primary coolant circuit where iodine is plated-out will be evaluated. This paper describes the testing plan and the preliminary analytical study on the release behavior of iodine and xenon isotopes through the operation of HTTR.Copyright

Thermochemical Hydrogen Production IS process

The Japan Atomic Energy Agency (JAEA) is conducting research and development on nuclear hydrogen production using High Temperature Gas-cooled Reactor and thermochemical water-splitting Iodine-Sulfur (IS) process aiming to develop large-scale hydrogen production technology for “hydrogen energy system”. In this paper, the present status of R&D on IS process at JAEA is presented which focuses on examining integrity of such components as chemical reactors, separators, etc. Based on previous screening of materials of construction mainly from the viewpoint of corrosion resistance in the harsh process conditions of IS process, it was planned to fabricate the IS components and examine their integrity in the process environments. At present, among the components of IS process plant consisting of three chemical reaction sections, i.e., the Bunsen reaction section, the sulfuric acid decomposition section and the hydrogen iodide decomposition section, key components in the Bunsen reaction section was fabricated.Copyright

Development Program of IS Process Pilot Test Plant for Hydrogen Production With High-Temperature Gas-Cooled Reactor

At the present time, we are alarmed by depletion of fossil energy and effects on global environment such as acid rain and global warming, because our lives depend still heavily on fossil energy. So, it is universally recognized that hydrogen is one of the best energy media and its demand will be increased greatly in the near future. In Japan, the Basic Plan for Energy Supply and Demand based on the Basic Law on Energy Policy Making was decided upon by the Cabinet on 6 October, 2003. In the plan, efforts for hydrogen energy utilization were expressed as follows; hydrogen is a clean energy carrier without carbon dioxide (CO2 ) emission, and commercialization of hydrogen production system using nuclear, solar and biomass, not fossil fuels, is desired. However, it is necessary to develop suitable technology to produce hydrogen without CO2 emission from a view point of global environmental protection, since little hydrogen exists naturally. Hydrogen production from water using nuclear energy, especially the high-temperature gas-cooled reactor (HTGR), is one of the most attractive solutions for the environmental issue, because HTGR hydrogen production by water splitting methods such as a thermochemical iodine-sulfur (IS) process has a high possibility to produce hydrogen effectively and economically. The Japan Atomic Energy Agency (JAEA) has been conducting the HTTR (High-Temperature Engineering Test Reactor) project from the view to establishing technology base on HTGR and also on the IS process. In the IS process, raw material, water, is to be reacted with iodine (I2 ) and sulfur dioxide (SO2 ) to produce hydrogen iodide (HI) and sulfuric acid (H2 SO4 ), the so-called Bunsen reaction, which are then decomposed endothermically to produce hydrogen (H2 ) and oxygen (O2 ), respectively. Iodine and sulfur dioxide produced in the decomposition reactions can be used again as the reactants in the Bunsen reaction. In JAEA, continuous hydrogen production was demonstrated with the hydrogen production rate of about 30 NL/hr for one week using a bench-scale test apparatus made of glass. Based on the test results and know-how obtained through the bench-scale tests, a pilot test plant that can produce hydrogen of about 30 Nm3 /hr is being designed. The test plant will be fabricated with industrial materials such as glass coated steel, SiC ceramics etc, and operated under high pressure condition up to 2 MPa. The test plant will consist of a IS process plant and a helium gas (He) circulation facility (He loop). The He loop can simulate HTTR operation conditions, which consists of a 400 kW-electric heater for He hating, a He circulator and a steam generator working as a He cooler. In parallel to the design study, key components of the IS process such as the sulfuric acid (H2 SO4 ) and the sulfur trioxide (SO3 ) decomposers working under-high temperature corrosive environments have been designed and test-fabricated to confirm their fabricability. Also, other R&D’s are under way such as corrosion, processing of HIx solutions. This paper describes present status of these activities.Copyright