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Power NASA Space United States Science

ORNL Restores US Capability To Produce Plutonium-238 (ornl.gov) 129

hypnosec writes: Oak Ridge National Laboratory has successfully produced 50 grams of plutonium-238, an isotope that produces heat without a lot of other, problematic radiation. This makes it suitable for use in radioisotope thermoelectric generators, which can power space probes. The new sample effectively revives the U.S.'s end-to-end plutonium-238 production capabilities, which have been dormant for around 30 years since work was stopped at the Savannah River Plant in South Carolina. The ORNL is optimistic this important milestone will pave the way for regular production of the material, ensuring constant supply for NASA's future missions.
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ORNL Restores US Capability To Produce Plutonium-238

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  • ... until your rover detonates. :P

  • WE don't want some random Libyan terrorist stealing it and recruiting a local mad scientist to make nuclear bomb. But if the scientist steals the Plutonium to make a time machine...
  • by mlts ( 1038732 ) on Wednesday December 23, 2015 @12:04AM (#51169519)

    Yes, it is radioactive, and yes, it is a very nasty heavy metal... but there are still pacemakers ticking away with this stuff as the "battery" 25+ years later.

    I wonder if Pu-238 might have some use in areas where batteries are needed and extremely hard to replace other than space projects. Definitely not for a battery for a smartphone, because we don't want Youtubers like TechRax to get radiation poisoning, but airline flight data recorders come to mind.

    • It can be very useful as a heater in various applications, dead-nuts reliable and not too dangerous if you encase is properly.

    • by evilviper ( 135110 ) on Wednesday December 23, 2015 @12:40AM (#51169659) Journal

      but airline flight data recorders come to mind.

      Terrible idea. First, flight data recorders have easy access to ample power (from the aircraft) for 99.9% of their life... It's only that 0.1% of the time that batteries would have to kick-in, and rechargeable NiMH work great and can last for decades in such an easy duty-cycle.

      Secondly, an RTG costs more than your HOUSE, and is huge.

      Third, PU-238 doesn't make electricity, just heat, so you need a full heat engine in there, somewhere. A simple Peltier works, but they're maybe 90% efficient, so you're talking extremely high temperatures to generate a useful amount of electricity, which need to be conducted out somewhere. That means your iPhone or flight data recorder power by PU-238 will have to run several-hundred degrees hotter than you'd find comfortable...

      • by evilviper ( 135110 ) on Wednesday December 23, 2015 @12:45AM (#51169673) Journal

        Ugg... Peltiers are about 10% efficient, meaning you'll need to dump 90% of the heat coming out of the PU-238...

        Stupid 4+ minute wait.

        • by mlts ( 1038732 )

          It does make sense though. I was assuming by "thermal-electric" generator that a heat engine was involved in the process with a reverse Peltier method.

          In general, nuclear (be it fission, elements for radioactive decay, etc) is to be way underused, just due to the sheer and unwarranted fear of it. Yes, it has its dangers, but if used right, it can solve a lot of the world's major problems. It doesn't suffer fools gladly... but neither did steam energy, nor early internal combustion prototypes.

          • The difference though, is that when steam and ICE failed to suffer a fool, it was only the fool and possibly a few bystanders that were harmed. When a nuclear power source fails to suffer a fool, you've generally got some nasty environmental contamination on your hands, and it's unlikely that anyone is going to be willing to clean it up even if they are able. Fukushima springs to mind, but even a plutonium pacemaker that doesn't get removed before cremation is going to be a nasty little local issue. Not t

      • It's that .1% of time after the plane crashes that really matters. The NiMH batteries last what.... 30 days? A lot of searches have lasted a lot longer.

        • 30 days? A lot of searches have lasted a lot longer.

          Very few searches last that long, and power to the FDR pretty much only helps in large water body crashes. If it's in a field somewhere, you just go around with a metal detector until you find something. Even underwater, you're assuming only power is running out, when a high-speed crash could damage the pinger, and being buried under debris could obscure and render it ineffective.

          Doubling the capacity of the batteries would add maybe $20 to the cost of

    • by plopez ( 54068 )

      As I pointed out else where Pu-238 is toxic and the waste products and chemicals used in its manufacture are toxic. The waste will doubtless be stored on site and ORNL is built on karst.

    • The Russians used to use RTGs to power remote, badly-accessible lighthouses and navigation beacons in the Arctic region. The USAF has RTG-powered radar stations in Alaska.

      The reason RTG's aren't more common: Pu-238 is incredibly expensive. The DOE has invested $15M/year to produce (eventually) 1.5 kg of Pu-238/year, which can produce ~750 W.

      • by nojayuk ( 567177 ) on Wednesday December 23, 2015 @05:54AM (#51170487)

        Most if not all of the Soviet-era lighthouse RTGs used Sr-90, an isotope of strontium rather than Pu-238 as a heat source. It required heavier shielding than a Pu-238 RTG but in land-based generators the extra mass of the case didn't affect its capabilities the way an RTG to be mounted on a spacecraft would.

        Sr-90 can be sourced from spent fuel from power plants and the Soviets had a fuel reprocessing capability to produce Sr-90 in quantity. The Russian government is looking to upgrade and expand their existing fuel reprocessing operations, in part to supply their next-generation series of fast reactors like the BN-800 with recycled spent fuel.

    • Some pacemakers use tritium (half life, around 9 years) in a betavoltaic generator, which is a lot easier to make small than a RTG. Tritium is a lot cheaper than Pu-238.
    • by delt0r ( 999393 )
      citation required. Pu238 has never been used in a pacemaker.
    • They have been used in Antarctica I think, eg. by the USSR
  • Per battery (Score:5, Informative)

    by ChrisMaple ( 607946 ) on Wednesday December 23, 2015 @01:06AM (#51169743)
    It looks like about 4 kg of plutonium-238 is required for a Mars Rover type mission. (Inferred from wikipedia article)
    • So does the Pu-238 act as a trickle charger for the battery banks on-board the rover, charging them during periods of inactivity or when needed? Or, can the Pu-238 source power the rover directly?

  • by Anonymous Coward on Wednesday December 23, 2015 @01:45AM (#51169859)

    The process described starts with a solid Neptunium-237 oxide, mixes it with Aluminum, presses it into pellets, irradiates it, chemically separates the Plutonium-238, and then processes it back into a solid oxide. They don't say where the Neptunium itself comes from, other than mentioning an existing inventory. It can be recovered from spent fuel, using another convoluted process starting with solid oxides.

    Creating 237Np would be a far more direct process with a LFTR [wikipedia.org], where the 2% of the fuel which does not fission mostly finds its way to be this very isotope. (The remainder become short-lived fission products.) Naturally, processing a liquid is easier than going through multiple solid oxide steps, and lends itself to a continuous process capable of producing 238Pu in volume. It would be far more interesting if ORNL were developing the processes for this instead.

    • Re: (Score:3, Insightful)

      by eis2718bob ( 659933 )

      This is the only comment (out of 49 so far) in this thread which is intelligent, useful, and constructive. There was a time (oh you youngsters!) when this was the rule, not the exception, on slashdot. The hamster comment deserves credit for humor, though.

      Is there a better site for news for nerds?

      • by bigpat ( 158134 )

        Is there a better site for news for nerds?

        Just set the slider at the top of the comment section to only display 2 and above comments or even 3 and above comments.

      • by KGIII ( 973947 )

        In the past week, I've gone over a few old articles and read every one of the comments. Two subjects spring to mind. The first is Mozilla with Firefox and the other is VMware. A common theme was that Firefox would never catch on with the masses and IE would remain king on the desktop. VMware was useless, a fad, vaporware that couldn't work, and virtual machines would never be of interest to anyone in the future, ever.

        I used to have a much lower UID but I got busy, stopped participating, lost the email addre

    • there is use for Np-237 in reactor core dosimetry and U.S. DOE labs supply it for that purpose. It is separated from normal spent fuel, about 1 part Np 237 per thousand parts plutonium is made

    • They don't say where the Neptunium itself comes from, other than mentioning an existing inventory.

      U.S. supplies of this are a byproduct of plutonium separation for weapons. I don't have exact figures handy, but the U.S. holds some tons of separated Np-237.

  • Mars-2020 and Europa-2025 have dibs on two of the missions. And you have to decide many years in advance which power source to use.

    Jupiter is border line solar. Most of its probes have been nuclear. But Juno due to arrive shortly has 180 feet of solar panels. Juno is designed to last only a short time because it is flying through Jupiters highly toxic geomagnetic fields to study them.

    I recall NASAs supply partly came from decommissioned Soviet warheads. But that process is now over.
  • "Let's splurge. Bring us some fresh Plutonium-238, the freshest you've got - this year's - no more of this old stuff"

How many hardware guys does it take to change a light bulb? "Well the diagnostics say it's fine buddy, so it's a software problem."

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