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PRESENT STATUS OF HTGR AND HYDROGEN PRODUCTION DEVELOPMENT IN JAEA
Introduction
In recent years, 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. Therefore, it is
universally recognised that hydrogen is one of the best energy media and its demand will increase
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 utilisation were expressed as follows; hydrogen is a clean energy carrier without
carbon dioxide (CO 2 ) emission, and commercialisation 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 CO 2
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-sulphur (IS)
process is one of the promising candidates to produce hydrogen effectively and economically. The
project of hydrogen production by IS process with the High-temperature Engineering Test Reactor
(HTTR) has been proceeded at the Japan Atomic Energy Agency (JAEA) to meet massive demand of
future hydrogen economy. The HTTR with 30 MW of thermal power is the only Japanese HTGR, built
and operated on the site of the Oarai Research and Development Centre of JAEA. Under the HTTR
project, JAEA has been developing the thermochemical IS process step by step.
This paper presents the 2100 vision of JAEA on future perspective of energy supply, especially on
HTGR utilisation in the field of iron manufacturing, chemical industries, oil refineries, etc. In addition,
this paper presents the present status of the HTTR Project including research and development
activities of HTGR reactor technology, hydrogen production technology with the thermochemical
water-splitting IS process, and the commercial HTGR plant design.
Hydrogen production with HTGR
The HTGR, which is graphite-moderated and helium-cooled, is particularly attractive due to its unique
capability of producing high temperature helium gas in addition to its fully inherent and passive
safety characteristics (Shiozawa, 2005). The HTGR-based production of hydrogen, the energy carrier
for an emerging hydrogen economy, is expected to be among the most promising applications to solve
the current environmental issues of CO 2 emission. With this understanding the development studies
of HTGR cogeneration system including hydrogen production have been carried out in Japan.
Until now, hydrogen is being used as raw materials of chemical products such as ammonia, but
hardly used as an energy carrier like electricity. In the near future, however, hydrogen will be widely
used as clean energy carrier for fuel cells to generate electricity, because hydrogen can significantly
contribute to reduce greenhouse gas emissions and fuel cells are being rapidly developed in the world.
Research and development (R&D) of fuel cell vehicles (FCV) and stationary power generators have
intensified all over the world.
Figure 1 shows an expected amount of hydrogen demand in the future on the basis of the
introduction target of FCV and fuel cells for household. The current total number of vehicles in Japan
is about 75 million and substantial increase of vehicles is not expected in the future, considering the
non-increase in the population. Hydrogen demand in the country was only 0.15 Gm 3 in 2000, but
might rapidly grow according to the target of the Japanese government to introduce 5 million of FCV
by 2020 and 15 million of FCV by 2030 (NEDO, 2005).
Hydrogen must be artificially produced from raw materials and energy, since hydrogen exists
scarcely in the nature. Figure 2 briefly explains methods of hydrogen production. The conventional
hydrogen production process in industry is mainly the steam reforming of methane (natural gas), in
which a large amount of carbon dioxide (CO 2 ) emission is inevitable by any means unless proper carbon
management is taken. On the other hand, hydrogen production without significant emission of CO 2 is
possible by water electrolysis or thermochemical water-splitting using natural energy (renewable
energy) or nuclear energy. However the cost of electrolysis production is thought to be expensive
48 NUCLEAR PRODUCTION OF HYDROGEN – © OECD/NEA 2010