Last week I had another opportunity to give a “TechTalk” at Google and I chose to spoke on how saving the uranium-233 inventory at Oak Ridge could allow us to produce power-generating radioisotopes to explore space and to extract life-saving medical radioisotopes.
The video might not be ready for a few weeks, so I wanted to go ahead and post the slides.
“Save the Uranium-233 to Save Solar System Exploration” (PPT with notes, 4.6MB)
I did things a little differently on this presentation than usual, with the slides consisting almost totally of images and a narration included in notes along with the slides. To enjoy the presentation more in the manner it was given at Google, I recorded a narration, which is a substantially larger download, but if you’d like to hear me telling the story this is probably the better one to watch/listen.
“Save the Uranium-233 to Save Solar System Exploration” (PPT with audio narration, 18.1MB)
I wasn’t terribly happy with the audio quality of the narration, so if anyone has better ideas or wants to re-record it with better equipment feel free.
Excellent as always. For the record: I could read the ppt and notes with openoffice (actually LibreOffice for Mac 3.3RC4). I couldn’t get the audio to play.
I note that the anti-nuclear Schmidt is moving to a different role in Google. And I’ll bet their efforts to create RE<C has put a dint in their confidence about renewables. Wouldn't it be great if the new management figured out that the world, which is their oyster, is going to go downhill badly if we don't make nuclear power work.
Sorry about the audio problems…I didn’t get a chance to listen to the whole narration after I recorded it but I did notice that some of the slides had some audio problems.
There’s a lot of great folks at Google thinking about thorium. Maybe something exciting will come out of it.
Thank you very much.
A very good speech. So smart to highlight the benefits, with LFTR and not to destroy the U233.
The rest of the day I think of your slide show and just filled with hope for the future. You should get a tip if you have not had time to see it:
With 30-40% efficiency becomes Pu238 batteries well on earth (other than Russian lighthouses).
http://www.gizmag.com/researchers-create-more-efficient-thrmoelectric-material/17632/
http://www.nature.com/nchem/journal/vaop/ncurrent/full/nchem.955.html
Yours sincerely Gunnar
Sorry I was to fast, not 30-40% but much more than todays, thermoelectric materials…….. if they can deliver 14% efficiency it would be fine.
Isn’t U-232 also useful for an RTG?
No, U-232 isn’t a good choice for an RTG because its decay chain has hard gamma emissions. Pu-238 decays to U-234 that has a very long half-life and little emissions.
Downblending the U-233 stocks because they want to shutter the storage building? Now it’s confirmed – our government energy programs are being run by bureaucratic, proliferation-blinded idiots. Time to start learning Chinese.
Thank you for this very nice presentation.
One comment regarding the use of radio-isotopes in space: the presentation only talks about feeding their energy to RTG generators, which is current practice. However I expect that thermo-photovoltaic energy conversion will be used in the future. It has following advantages:
- much larger scaling for high-energy applications (i.e. electric propulsion)
- about 30% conversion efficiency is possible with present technology.
In one sentence: Pu-238/Sr-90 production -> Thermo-photovoltaic energy conversion in space -> MPD thrusters -> very much enhanced capabilities from current practice
The details of this concept are described here:
http://www.astrophys-space-sci-trans.net/6/19/2010/astra-6-19-2010.pdf
The funny thing about Np-237 is that it’s the isotope which is most credibly a proliferation threat in a fuel cycle with commercial reprocessing.
Everybody and his brother is worried about Pu, but Pu formed in a commercial fuel cycle is always going to contaminated with Pu-238, Pu-240 and Pu-241 which are undesirable in nuclear weapons.
Although Np-236 is long lived, Np-236 is not produced by neutron capture, so Np separated from a commercial fuel cycle is almost pure Np-237. This has a critical mass similar to HEU and has a very low spontaneous fission rate, so it’s a desirable material for a crude gun-type fission bomb. Even if a commercial reprocessing system never separates pure Np-237, it would be relatively easy to chemically separate Np-237 from an actinide mixture or from an aged mixture of Np-237 + fission products.
(Note you want to get the Np-237 away from the fission products anyway, because Np-237 is long-lived)
In the long term, commercial reprocessing systems should do something with the Np-237 they accumulate. Np-237 is a good fast reactor fuel, and it could also be blended into LWR fuel or FBR blanket material, which would cause the rapid production of Pu-238, which would make a Pu-cycle system all the more proliferation proof.
Of course, that Np-237 could also be fabricated into targets that are free of U-238 and produce pure Pu-238 for space exploration and other uses. (On cold days like this, I wish I had a pile of Pu-238 pellets in my house!)
How can I support this?
Just curious, what is the actual purpose of RTGs given the fact they can produce 2000 Watts at max (from your slides) from a few tens kg of plutonium ? I guess to produce electricity on board for a very long time not to move spacecrafts themself, or what ?