Slashdot Mirror
New Small Fission Reactor For Deep-space Missions Demonstrated
cylonlover writes "Exploring the regions of deep space beyond Mars means sending probes where solar power isn't practical. Since the 1960s, NASA has equipped its Apollo missions and unmanned explorers with Radioisotope Thermal Generators (RTGs). These have worked very well, but they run on plutonium 238, which is currently in short supply. Therefore, the Los Alamos National Laboratory is developing a new small nuclear reactor for spacecraft that uses uranium instead of plutonium to power Stirling engines and generate electricity. At the Nevada National Security Site's Device Assembly Facility near Las Vegas, engineers from Los Alamos, the NASA Glenn Research Center and National Security Technologies LLC conducted a Demonstration Using Flattop Fissions (DUFF) experiment that produced 24 watts of electricity using a pair of free-piston Stirling engines."
This is the most beautiful poetry I have ever seen. Oh my God.
It's probably less the number of probes we're sending, and more the general decrease in amount of Plutonium. PU hasn't been manufactured much since the end of the cold war; everybody is busy stepping down their weapon programs instead. Now, some of that former-warhead material is great for RTGs, but the stuff degrades. It has a moderately short half-life (it has to, or it wouldn't be active enough to passively generate the heat needed for an RTG) and a lot of the stuff that was viable for spacecraft 30 years ago is pretty cold now (see the Voyager probes, for example, which are running on extremely low power).
They can't just fix the problem by sending more, either; not only is it in short supply in general, but it's too heavy to send much on a spacecraft. Instead, they send enough to run the mission at full capacity for a few years, scaling back over time. That requires a supply of pretty fresh / pure Plutonium though, and that means making and separating more of it... except doing runs into a serious political problem. We *could* keep using RTGs (although they aren't perfect by any means, they get the job done) if we could convince people to let us manufacture their fuel source...
There's no place I could be, since I've found Serenity...
You must be a Vogon.
Only critical if combined. If the rocket breaks apart or the engines explode, the core would fall apart; it lacks the explosives necessary to bring the Uranium to super-criticality. Worst likely case would be that the control rod gets jammed but the housing stays intact, but the cooling system is destroyed, leaving the core at critical and causing a meltdown. The odds of that seem extremely low, though.
It'd be a very nasty "dirty bomb" if it blew up in the atmosphere, but no more than that, and a slug of Plutonium hot enough to run a spacecraft for a few years or even decades is a nasty thing to blow up in the atmosphere too. We've been launching those for decades, though.
There's no place I could be, since I've found Serenity...
It seems like you're confusing Pu-239, which is used in weapons and has a half-life of 24000 years, with Pu-238, which is not used in weapons and has a half-life of around 90 years.
It's wouldn't be objectively any nastier than the other toxic substances such as hydrazine that would be sprayed all over the place in an explosion. "Dirty bombs" are not something to be taken seriously. Blowing up an equal mass of mercury would be more dangerous than the uranium, and the damage uranium would pose is more that it is a heavy metal than due to it being radioactive.
"Dirty bombs" are a true terrorism weapon - they cause far more terror than is actually justified, just like the 9/11 attacks did for air travel. Radiation is all scary and mysterious and dangerous and Chernobyl and Fukushima and OMG we're all gonna die!
That's their purpose, more than actually causing fatalities.
Just because you're paranoid doesn't mean there isn't an invisible demon about to eat your face
even depleted u-238 can be used in the right type of reactor, and thorium too. we have millenia of fission fuel supply, we just need to start using smart designs rather than the primative and dangerous gen i and ii
My father was is the first lot of troops into Nagasaki and he stayed there for as part of the Japanese Occupation Force. They were given no warnings about radiation, no protective equipment, and allowed to pick and pry wherever they wanted among the ruins. HIs photos were taken from pretty much every part of the city.
He had no health problems that could be attributed to radiation. Those of his friends and shipmates who were there also were the same. In every case when they suffered serious ill health it was due to smoking or drinking.
What I have noticed though is curious congenital conditions occasionally popping up in their children, about 1 child in 4 or 5, when there was no history of it previously. This may or may not be coincidence but while these conditions may be awkward for those that have them, no-one has died from one yet.
I myself have worked with radioactive materiels and while they creep the bejesus out of anyone who has anything to do with them the radiation is not overly dangerous at low levels except over long periods, say taking x-rays every day. Even spending six months in Nagasaki starting two weeks after they dropped a plutonium bomb on it didn't cause any problems among the people I know who did it.
I said - don't look Ethel!..., but it was too late..., she'd already looked.
It's a HaiKKKu
Table-ized A.I.