Author Topic: Good news on the Plutonium production issue  (Read 88920 times)

Offline Avron

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Re: Good news on the Plutonium production issue
« Reply #60 on: 12/20/2013 01:37 pm »

It has taken the US decades and several Billion to develop it's current RTG technology. It is not something you can do overnight. It would eat India's entire space budget, leaving none for rockets or space missions.

is a 1950 technology using a heat source and thermocouples.. its very simple .. it will take India less that three months to get it running if needed.. the Russians could easy supply.

Offline GuessWho

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Re: Good news on the Plutonium production issue
« Reply #61 on: 12/20/2013 04:15 pm »

is a 1950 technology using a heat source and thermocouples.. its very simple .. it will take India less that three months to get it running if needed.. the Russians could easy supply.

And the expertise you possess to make this kind of statement is ....?

Offline DMeader

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Re: Good news on the Plutonium production issue
« Reply #62 on: 12/20/2013 04:38 pm »
is a 1950 technology using a heat source and thermocouples.. its very simple .. it will take India less that three months to get it running if needed.. the Russians could easy supply.

I doubt that India has either the infrastructure or the expertise to produce and separate the required plutonium isotope, and acquiring those would take a lot longer than three months.

Offline savuporo

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Re: Good news on the Plutonium production issue
« Reply #63 on: 12/20/2013 04:57 pm »
You need other elements, Pu-238 has a half life of 87.7 years, and generates a fair amount of internal heat, hence it's current use.
It's worth mentioning that Polonium-210 is a viable alternative, and  Americium-241 is apparently being considered.
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Offline hop

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Re: Good news on the Plutonium production issue
« Reply #64 on: 12/20/2013 05:15 pm »
It's worth mentioning that Polonium-210 is a viable alternative,
Not really, the half life is much to short for most the types of missions you would want to use RTGs for.  The Soviets used it for heaters on Lunokhod, but they didn't have a long cruise and had a design life of months. It would be no good for outer planets missions or long duration missions like MSL. Am-241 and Sr -90 could be used, but they have very significant drawbacks.

India does have substantial indigenous nuclear expertise, including working with plutonium, so there's little reason to think couldn't make RTGs if they wanted to. Looking at the cost and difficulty of the US restart should make it clear the suggestion they could do it in months is implausible.

Offline savuporo

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Re: Good news on the Plutonium production issue
« Reply #65 on: 12/20/2013 05:20 pm »
Not really, the half life is much to short for most the types of missions you would want to use RTGs for.  The Soviets used it for heaters on Lunokhod, but they didn't have a long cruise and had a design life of months.
Well, Lunokhod-2 worked for 4 months, and didnt die of cold. For applications like exploring lunar poles i think it would be entirely appropriate.
A complete guess, but i think there is a good chance that heaters in Chang'e are polonium as well, especially considering that Chinese specialists apparently have been to Sarov on couple of occasions. 
« Last Edit: 12/20/2013 05:24 pm by savuporo »
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Offline Avron

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Re: Good news on the Plutonium production issue
« Reply #66 on: 12/20/2013 05:20 pm »

is a 1950 technology using a heat source and thermocouples.. its very simple .. it will take India less that three months to get it running if needed.. the Russians could easy supply.

And the expertise you possess to make this kind of statement is ....?

Not sure why it has to be personal .. any way...

"According to the 2012 SIPRI Yearbook, the Indian arsenal comprises 80 to 100 warheads.[1] The ranges of such estimates are generally dependent on analyses of India's stockpile of weapons-grade plutonium, estimated at 0.54 ± 0.18 tons.[2] Although India has also stockpiled roughly 2.4 ± 0.9 tons of highly enriched uranium (HEU), some of this material is most intended for use in nuclear submarines and research reactors"

eh .. thats half a ton of  weapons-grade plutonium. And you thought that only the US had any capability.. well Russia has been running Lighthouses on RTG's..

edited to add ref link : http://www.nti.org/country-profiles/india/nuclear/
« Last Edit: 12/20/2013 05:26 pm by Avron »

Offline Kryten

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Re: Good news on the Plutonium production issue
« Reply #67 on: 12/20/2013 05:35 pm »
 RTG's use plutonium-238, weapons use plutonium-239; the processes of producing and refining the two are completely different.

Offline Avron

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Re: Good news on the Plutonium production issue
« Reply #68 on: 12/20/2013 06:24 pm »
RTG's use plutonium-238, weapons use plutonium-239; the processes of producing and refining the two are completely different.

Correct they are different..  one needs U238 and the other U235..  both need irradiated by reactor neutrons, P238 needs  a chemical separation and some more irradiated by reactor neutrons ..  and it you want you can get P238 from your spent fuel rods or plutonium producing reactors, just needs some separation that is a tad more expensive .
« Last Edit: 12/20/2013 06:26 pm by Avron »

Offline Kryten

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Re: Good news on the Plutonium production issue
« Reply #69 on: 12/20/2013 06:30 pm »
 That technique would require you to separate the Pu-238 from the Pu-239, which would be incredibly difficult. Actual production involves neutron bombardment of Neptunium-237 followed by chemical separation, and Np-237 isn't easy to produce in the first place.

Offline savuporo

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Re: Good news on the Plutonium production issue
« Reply #70 on: 12/20/2013 06:40 pm »
Am-241 and Sr -90 could be used, but they have very significant drawbacks.
ESA view on am-241 situation described here

http://www.lpi.usra.edu/meetings/nets2012/pdf/3029.pdf

Quote
The existing stocks of plutonium at Sellafield are more than sufficient for the production of multiple 241-Am-based RTGs each year for a number of years.

http://www.oosa.unvienna.org/pdf/pres/stsc2012/tech-18E.pdf
http://www.europeanthermodynamics.com/news/wp-content/uploads/2013/04/LeicesterUniSpace3.pdf

Oh, they are looking at stirlings too, and 4-watt RTG output prototype in testing.
« Last Edit: 12/20/2013 06:46 pm by savuporo »
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Offline hop

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Re: Good news on the Plutonium production issue
« Reply #71 on: 12/20/2013 07:53 pm »
Well, Lunokhod-2 worked for 4 months, and didnt die of cold. For applications like exploring lunar poles i think it would be entirely appropriate.
Yes, it works for short duration missions like this, but as I said this is a very narrow subset of the kind of space missions you want RTGs for. A dubious investment unless you are sure you aren't going to want to use them anywhere else.

Po-210 has a half life of 138 days, so even for lunar exploration it would be insufficient for missions that are intended to last much longer than Lunokhod-2, unless it was vastly overpowered to start with.
Quote
A complete guess, but i think there is a good chance that heaters in Chang'e are polonium as well, especially considering that Chinese specialists apparently have been to Sarov on couple of occasions. 
The Chinese have said they are using Pu-238. This was discussed quite a bit in the Chang'e thread.


Offline Avron

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Re: Good news on the Plutonium production issue
« Reply #72 on: 12/21/2013 05:42 pm »
That technique would require you to separate the Pu-238 from the Pu-239, which would be incredibly difficult. Actual production involves neutron bombardment of Neptunium-237 followed by chemical separation, and Np-237 isn't easy to produce in the first place.

Np-237 is made how? 

Take ur old spent fuel rods  and add barium and simmer at approx 1200C
2 NpF3 + 3 Ba → 2 Np + 3 BaF2

Offline savuporo

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Re: Good news on the Plutonium production issue
« Reply #73 on: 12/21/2013 05:44 pm »
The Chinese have said they are using Pu-238. This was discussed quite a bit in the Chang'e thread.
No, i dont think they ever talked about their fuel source. Discussed yes, but there is no information available from official sources that would confirm that. It could be either Po-210 or Pu-238, and its highly unlikely we will know.
« Last Edit: 12/21/2013 05:45 pm by savuporo »
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Offline Avron

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Re: Good news on the Plutonium production issue
« Reply #74 on: 12/21/2013 06:06 pm »
It would be nice for someone to get Americium-241  working.. ok its 25% power, and needs approx 2cm lead for enclosure but has a half life of 400plus years

Offline GuessWho

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Re: Good news on the Plutonium production issue
« Reply #75 on: 12/22/2013 01:18 pm »
That technique would require you to separate the Pu-238 from the Pu-239, which would be incredibly difficult. Actual production involves neutron bombardment of Neptunium-237 followed by chemical separation, and Np-237 isn't easy to produce in the first place.

Np-237 is made how? 

Take ur old spent fuel rods  and add barium and simmer at approx 1200C
2 NpF3 + 3 Ba → 2 Np + 3 BaF2

Actually no.  Np-237 is separated out using the PUREX process which uses tributyl phosphate (TBP).  That solution goes through a number of reductions in oxidation states before being precipitated out as neptunium oxalate and then calcined into neptunium oxide.  Then as stated before, the Np-237 is fabricated into targets and irradiated by a high neutron flux to produce Pu-238 which must then be separated, reacted to form PuO2, and then formed into high density compacts before it can be used as a radioisotope heat source.  And that is only the start as significant work post compact forming is needed to encapsulate and protect the PuO2.  And beyond that, one has to design a structural support around the PuO2 fuel forms to prevent release of the PuO2 under potential accident scenarios as PuO2 is highly toxic.  Hardly something one does in 3 months as you claim.  But perhaps you have an advanced degree in nuclear physics,  inorganic chemistry, materials science or specialty manufacturing that enables you to do all this in 3 months.  Hence my prior question; what expertise do you possess to make this kind of statement?

Offline john smith 19

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Re: Good news on the Plutonium production issue
« Reply #76 on: 12/25/2013 11:14 am »
Actually no.  Np-237 is separated out using the PUREX process which uses tributyl phosphate (TBP).  That solution goes through a number of reductions in oxidation states before being precipitated out as neptunium oxalate and then calcined into neptunium oxide.  Then as stated before, the Np-237 is fabricated into targets and irradiated by a high neutron flux to produce Pu-238 which must then be separated, reacted to form PuO2, and then formed into high density compacts before it can be used as a radioisotope heat source.  And that is only the start as significant work post compact forming is needed to encapsulate and protect the PuO2.  And beyond that, one has to design a structural support around the PuO2 fuel forms to prevent release of the PuO2 under potential accident scenarios as PuO2 is highly toxic.  Hardly something one does in 3 months as you claim.  But perhaps you have an advanced degree in nuclear physics,  inorganic chemistry, materials science or specialty manufacturing that enables you to do all this in 3 months.  Hence my prior question; what expertise do you possess to make this kind of statement?
A succinct description of a very complex process. You also politely side stepped the fact most of this process has to be handled remotely due to radiation exposure, substantially complicating things.

And of course that just gets you to the raw material, not the finished RTG design itself. :(

That said it's an interesting idea that India could act as a niche supplier in this area, enabling any nation that wanted to build a long duration space mission.

But not a simple task.  :(
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Offline GuessWho

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Re: Good news on the Plutonium production issue
« Reply #77 on: 12/26/2013 05:12 pm »
Actually no.  Np-237 is separated out using the PUREX process which uses tributyl phosphate (TBP).  That solution goes through a number of reductions in oxidation states before being precipitated out as neptunium oxalate and then calcined into neptunium oxide.  Then as stated before, the Np-237 is fabricated into targets and irradiated by a high neutron flux to produce Pu-238 which must then be separated, reacted to form PuO2, and then formed into high density compacts before it can be used as a radioisotope heat source.  And that is only the start as significant work post compact forming is needed to encapsulate and protect the PuO2.  And beyond that, one has to design a structural support around the PuO2 fuel forms to prevent release of the PuO2 under potential accident scenarios as PuO2 is highly toxic.  Hardly something one does in 3 months as you claim.  But perhaps you have an advanced degree in nuclear physics,  inorganic chemistry, materials science or specialty manufacturing that enables you to do all this in 3 months.  Hence my prior question; what expertise do you possess to make this kind of statement?
A succinct description of a very complex process. You also politely side stepped the fact most of this process has to be handled remotely due to radiation exposure, substantially complicating things.

And of course that just gets you to the raw material, not the finished RTG design itself. :(

That said it's an interesting idea that India could act as a niche supplier in this area, enabling any nation that wanted to build a long duration space mission.

But not a simple task.  :(

Well, I didn't want to write a book. :-)  To complete the story, you also have to consider that everything that remotely touches the process is contaminated and the legacy costs to clean that contamination problem will haunt you for decades.

Offline john smith 19

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Re: Good news on the Plutonium production issue
« Reply #78 on: 12/29/2013 10:11 pm »
Well, I didn't want to write a book. :-)  To complete the story, you also have to consider that everything that remotely touches the process is contaminated and the legacy costs to clean that contamination problem will haunt you for decades.
Powdered Pu. One of the those deadly materials on the planet.  :(

Even with lower labour costs in India that's not going to be a trivial expense.  :(

I came across a book on "teleoperators" and it discussed the system used to build and take down the NERVA test engines at the delightfully named "Jackass Flats" test site.

That took some serious engineering work to pull off.  :(

I know high neutron flux is the preferred way to do this but I always felt devising a way to leverage the large number of US PWR's would make it possible without specialist reactors. Many hands make light work so to speak.

OTOH I think you've made it clear Avron was being (shall we say?) optimistic on their time scale.
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Offline akula2

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Re: Good news on the Plutonium production issue
« Reply #79 on: 01/06/2014 08:35 pm »
I doubt that India has either the infrastructure or the expertise to produce and separate the required plutonium isotope, and acquiring those would take a lot longer than three months.
I'm quite sure India would have tremendously progressed without those unfair technology restrictions  ???

Yes, it works for short duration missions like this, but as I said this is a very narrow subset of the kind of space missions you want RTGs for. A dubious investment unless you are sure you aren't going to want to use them anywhere else.
You were close  :)

So Thorium RTGs almost impossible or not worth (costs)?

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