Re: Miniture Nuclear Batteries
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RussH said:
So, how did they test it for 98 years in 1969? Time machine? Seriously, there have been a number of small nuclear power supplies developed for such things as satellites, mainly by the Russians. We wouldn't want to pollute outer space, would we?
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Humm, something about half-life of the fuel in them.
Here is a link for the RTGs:
OFFICE OF SPACE & DEFENSE POWER SYSTEMS
Radioisotope Power Systems
History
Program Description
General Purpose Heat Source (GPHS)
Radioisotope Heater Units (RHU)
History
Publications and Fact Sheets
Cassini
The U.S. Department of Energy (DOE) has provided radioisotope thermoelectric generators for space applications since 1961. These generators provide electrical power for spacecraft by direct conversion of the heat generated by the decay of plutonium-238 (Pu-238) oxide to electrical energy. The first generator was used on the Navy Transit 4A spacecraft launched on June 29, 1961. Between 1961 and 1972, DOE provided power systems for six Navy navigational satellites. In addition, DOE provided power systems for two Air Force communications satellites, LES 8 and LES 9, both launched together on March 14, 1976
These solar system exploration missions have continued far beyond their design life of about 5 years each, with the Voyager spacecraft now having traveled through the solar system and beyond, providing data over the last 20 years. The Voyager spacecraft is expected to provide data for another 25 years.
They have even utilized them in recently launched things.
More info here:
http://www.ne.doe.gov/space/space-history.html
Also - you MIGHT check with the Coast Guard to see if they have info on very
similar devices (except they use Sr-90 instead of Pu-238) for powering bouys.
SNAP-27 Characteristics
The SNAP-27 power supply weighed about 20 kilograms, was 46 cm long and 40.6 cm in diameter. It consisted of a central fuel capsule surrounded by concentric rings of thermocouples. Outside of the thermocouples was a set of fins to provide for heat rejection from the cold side of the thermocouple.
Each of the SNAP devices produced approximately 75 W of electrical power at 30 VDC. The energy source for each device was a rod of plutonium-238 weighing approximately 2.5 kilograms and providing a thermal power of approximately 1250 W.
Plutonium-238 is a non-fissile isotope of plutonium that decays by alpha particle emission with essentially zero associated gamma emissions. This characteristic was very important for the ALSEP powering application, both because the instruments would have been negatively affected by interference from a gamma emitter and because the devices required close handling by lunar astronauts.
Even though the only radiation from Pu-238 is alpha particles which require little shielding, it is necessary to use thick gloves when handling a 2.5 kilogram rod of Pu-238. The surface temperature will reach about 500 degrees C because of the energy being released by radioactive decay. After ten years of continuous power output, a Pu-238 based RTG will still produce 92% of its initial power.
One measure of performance that is often used for chemical storage batteries is the amp-hour. A modern battery might have a capacity of 1.5 amp-hrs/kg. The SNAP-27 power supplies demonstrated the ability to provide more than 4380 amp-hrs/kg during the four years that their performance was monitored. Similar RTGs have produced 24,000 amp-hrs/kg during a 20 year operating life and are still going strong.
Other SNAP devices used various radioisotope's for power strontium, polonium, curium-242, Cesium, and of course Plutonium 238.
Additional work was conducted at Sanders Nuclear, a subsidiary of Sanders Associates of Nashua, New Hampshire and Cambridge Nuclear Corporation. There was work done on Thulium-170 and Thulium-171 isotopic powered thermoelectric converters.
In nuclear, Boeing's heritage includes development of space nuclear auxiliary power systems (SNAP 8 and SNAP 10A programs), high space power reactor systems (100 kWe SP-100 and 5 MWe Multi-Megawatt programs), and dynamic isotope power systems (2.5-to-6 kWe DIPS programs).
http://www.boeing.com/assocproducts/energy/spacepower.html
Be sure to check out the multi-megawatt (5,000,000 Watt) miniature nuclear power system....wonder what the use of that could be for... /ubbthreads/images/graemlins/wink.gif