"VEHICULES SOUS-MARINS"!
Source ADIT, octobre 2003: Japon, Successful Dive
by World's First Fuel Cell Research Submersible
http://www.jamstec.go.jp/jamstec-e/index-e.html
On August 12, 2003, the Japan Marine Science and Technology
Center (JAMSTEC) conducted a successful test of its deep-sea autonomous
underwater vehicle (AUV). The "Urashima" is the world's first research
submersible powered by a fuel cell. The AUV navigated at depths of up to
300 meters in Suruga Bay while technicians tested the electrical power
generating capacity and other functions. JAMSTEC aims to have the AUV make
an independent long-distance run of 300 kilometers during fiscal 2004.
When "Urashima" submerges to its maximum depth of
3,500 meters, the surrounding water pressure reaches 350 atmospheres and
the pressure inside the fuel cell reaches about 2 atmospheres. Compared
to the operation of fuel cell vehicles (FCVs) under normal atmospheric
pressure, under deep-sea conditions the fuel cell cannot easily emit the
trace amounts of impurities such as nitrogen and carbon dioxide contained
in hydrogen and oxygen gas, as well as the water generated through the
process of power generation. Furthermore, if this water is discharged outside
the vehicle, neutral buoyancy cannot be maintained.
"Urashima" therefore employs a "closed system" in
which these impurities and water accumulate inside the fuel cell. This
system requires more advanced technology than in FCVs under normal atmospheric
conditions and represents the world's first practical development of that
technology
