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Paolo
according to Flight International UK could use plutonium in space nuclear power demonstration
Drkskywxlt
http://www.spaceflightnow.com/news/n1007/09rtg/

ESA is getting serious about starting their own RTG production, with one official saying:
QUOTE
Southwood said in an interview with Spaceflight Now. "We are building for a pretty major capability being available in Europe in the 2020s."


However, ESA is looking at using americium, which produces less power and more neutron radiation. No explanation is given as to why that and not Pu-238.

NASA does not have enough Pu-238 for JEO currently, but will if the contract to buy plutonium from Russia can be renegotiated. Russia wants more money since they have the monopoly on plutonium. If those contracts are fulfilled, then there will be plenty for JEO.

Still waiting on approval of US restart of Pu-238 production.
stevesliva
QUOTE (Drkskywxlt @ Jul 9 2010, 11:43 AM) *
However, ESA is looking at using americium, which produces less power and more neutron radiation. No explanation is given as to why that and not Pu-238.


http://en.wikipedia.org/wiki/Americium-241

Since it's used in smoke detectors, there must be an industrial supply of it.
Drkskywxlt
QUOTE (stevesliva @ Jul 9 2010, 12:03 PM) *
http://en.wikipedia.org/wiki/Americium-241

Since it's used in smoke detectors, there must be an industrial supply of it.


Good thought...that may be it. But the article also mentions that ESA will talk to the nuke industries in the UK and France for guidance on how to begin. Maybe that's just for the RTGs themselves as opposed to the fuel?
AndyG
QUOTE (Drkskywxlt @ Jul 9 2010, 04:43 PM) *
ESA is looking at using americium, which produces less power and more neutron radiation. No explanation is given as to why that and not Pu-238.


Longer half-life gives you a gentler decay rate, of course. Handy for Cassini-length missions. And as electronics generally become more efficient, maybe the energy density of Pu is less of an advantage?

Andy
stevesliva
Since we were talking nuclear isotopes in this thread, I have a question regarding this:
http://www.nytimes.com/2012/02/07/science/...netium-99m.html

... they are basically kicking around ways to expose Mb-99 to a neutron source to create Tc-99.

Is this perhaps similar to how Pu-238 is created? By exposing Np-238 to a neutron source? Could strategic supplies of both isotopes be created in the same facility?
Holder of the Two Leashes
Plutonium 238 can be produced in usable purity in two different ways. Separate out neptunium 237 from spent reactor fuel. Place this in a reactor to expose it to neutrons. The Np-237 atoms that capture a neutron will either fission or form Np-238. Np-238 will decay to Pu-238 in short order. There will always be a little bit of Pu-239 contamination from double neutron capture. This is the standard process.

You can also make it from exposing americium 241 to neutrons, producing Am-242, which beta decays to Curium 242, then alpha decays to Pu-238. This method requires a high flux of neutrons.
Astro0
Thanks for the answer.

Could I suggest however that we leave this discussion here.
The thread, which was started two years ago, was about an ESA study.
The merits and possibilities of Pu238 production for RTGs has been discussed and debated elsewhere.

On past experience, the issue can run too close to breaching UMSF Rule 1.2 on contentious issues. Thanks.

Astro0 (UMSF Admin Team)
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