Am-242m Fission Fuel

["Wes Van Pelt" <vanpeltw@idt.net>]

Radsafers,
Here is an excerpt of the article
(http://www.beyond2000.com/news/Jan_01/story_953.html) on Am242m as a
fission fuel for space propulsion. Anyone know anything about Am242m???



A rare nuclear material, americium-242m, is the Israeli scientists'
suggestion. They report that Am-242m could maintain sustained nuclear
fission as an extremely thin metallic film, less than a thousandth of a
millimetre thick. In this form, the high-energy, high-temperature fission
products can escape the fuel elements and be used for propulsion.

It is not possible to obtain such fission-fragments from conventional
radioactive fuels such as uranium-235 and plutonium-239, as they require
large fuel rods to absorb the fission products. These would be an
impractically bulky addition to a space probe.

Professor Yigal Ronen sought to develop a lighter nuclear reactor not by
redesigning the hardware, but by examining alternative fuels. He found that
americium-242m was the best isotope, requiring only 1 per cent of the mass
of uranium or plutonium to reach its critical state. He determined that the
fuel could sustain fission in the form of thin films. The importance of the
discovery lies in the flexibility of its application: the fission products
can be used as a propellant themselves, to heat a gas for propulsion, or to
fuel a special generator that produces electricity.

"There are still many hurdles to overcome before americium-242m can be used
in space," says Ronen. "There is the problem of producing the fuel in large
enough quantities from plutonium-241 and americium-241, which requires
several steps and is expensive. But the material is already available in
fairly small amounts. In addition, actual reactor design, refuelling, heat
removal, and safety provisions for manned vehicles have not yet been
examined."

Ronen also says that he is sure the fuel will one day propel man with great
speed to Mars, as it is the only proven material whose fission products can
be made available for such high-speed propulsion.


Regards,
Wes

Wesley R. Van Pelt, PhD., CIH, CHP
Wesley R. Van Pelt Associates, Inc.
Consulting in Health Physics and Environmental Radioactivity.
mailto://vanpeltw@idt.net


************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html