Author Topic: Good news on the Plutonium production issue  (Read 57014 times)

Offline mlindner

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Re: Good news on the Plutonium production issue
« Reply #40 on: 03/22/2013 12:46 AM »
I have a question for people in the know based on the following from the article:

“We’re expecting reports from (the DOE) later this year on a complete schedule that would then put plutonium on track to be generated at about 3.3 pounds a year, so it’s going quite well,” Green said.

The fresh plutonium has the added benefit of reviving NASA's small and decaying supply of older plutonium still in storage.

“It fairly old -- more than 20 years,” Green said, “When we add newly generated plutonium through this process to the older plutonium in a mixture of one new-to-two old units, we can actually revive that and get he energy density we need. So for every 1 kilogram [2.2 pounds], we really revive 2 other kilograms of the older plutonium by mixing it.”

If they can revive old Plutonium stock with the newly produced Plutonium,  how much old stock do they have to use to boost the yearly total?


It's not really "reviving" anything. What they're doing is mixing the old part Pu-238 and Lead (from having decayed) with new 100% Pu-238 to make something that per unit has less lead than the old stuff. Basically they're degrading the new Pu-238 so they aren't forced to dump the old Pu-238. Presumably this is fine as a given mission only needs a certain power density and the RTGs or ASRG come in units so there is probably some excess power normally.
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Offline Blackstar

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Re: Good news on the Plutonium production issue
« Reply #41 on: 03/22/2013 01:20 AM »
I do not see anything changing until either NASA is given the right to produce its own Pu-238

Huh?  NASA doesn't desire, the manpower, facilities nor expertise to do it.  Also, it is a bad idea. 

Also illegal.

Offline iamlucky13

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Re: Good news on the Plutonium production issue
« Reply #42 on: 03/22/2013 01:41 AM »
I do not see anything changing until either NASA is given the right to produce its own Pu-238

Huh?  NASA doesn't desire, the manpower, facilities nor expertise to do it.  Also, it is a bad idea. 

Also illegal.

Obviously that's the first part he is suggesting should change, but oversight of nuclear materials in this country falls under the DOE for a reason, and fragmenting that role complicates the safety and security rationale behind it. Even the military has to work with the DOE on this stuff.

Offline DarkenedOne

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Re: Good news on the Plutonium production issue
« Reply #43 on: 03/22/2013 01:52 AM »
I'm considering responding point by point to what you wrote, but I'm not sure it's worth it. There are a bunch of half-true and incomplete statements above. For the record, I worked on both a high-level review of the Pu-238 supply issue and a study that dealt with planetary science for the next decade. Your statement about the Europa mission, for instance, is false. The killer was the cost, not Pu-238 availability. And NASA or a "commercial operation" cannot produce Pu-238. For starters, the source material, Neptunium, is owned by DoE, and furthermore, only DoE is legally allowed to produce these materials.

In any case, I'm pretty sure my statements are complete.  As far as being half-truths what I have stated the truth to the best of my ability.  If something I have said is incorrect then it is not intentional.  If you have the experience you say you have than your sources of information are better than mine.

Offline hop

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Re: Good news on the Plutonium production issue
« Reply #44 on: 03/22/2013 01:57 AM »
I'm considering responding point by point to what you wrote, but I'm not sure it's worth it.
Given that DarkenedOne already had a whole thread dedicated to the idea of NASA producing it's own pu back in 2011 http://forum.nasaspaceflight.com/index.php?topic=26927.0, it's hard to see the point.

It was a non-starter back then, and the only thing that has changed is that pu production is basically on track now.

Offline DarkenedOne

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Re: Good news on the Plutonium production issue
« Reply #45 on: 03/22/2013 01:58 AM »
I do not see anything changing until either NASA is given the right to produce its own Pu-238 or a commercial operation is able to supply it.

Neither will ever happen. As Jim points out, NASA doesn't *want* the former idea; furthermore, the latter is stupid and dangerous.

Sorry to break it to you, but there are a number of companies that sell isotopes that are produced in commercial reactors for uses in various industries including nuclear medicine.  That is not to mention the hundreds of research reactors at universities where they produce isotopes for their own experiments.
« Last Edit: 03/22/2013 01:59 AM by DarkenedOne »

Offline DarkenedOne

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Re: Good news on the Plutonium production issue
« Reply #46 on: 03/22/2013 02:30 AM »
I'm considering responding point by point to what you wrote, but I'm not sure it's worth it.
Given that DarkenedOne already had a whole thread dedicated to the idea of NASA producing it's own pu back in 2011 http://forum.nasaspaceflight.com/index.php?topic=26927.0, it's hard to see the point.

It was a non-starter back then, and the only thing that has changed is that pu production is basically on track now.

The important thing is that current and future spaceflight missions are not impeded by a lack of Pu-238.  It is very important if we want to continue to have a robust spaceflight program, especially if we want a robust manned program.

Who produces it and how is not as important.  People have been clamouring for the restart of plutonium production for many years now.  From what I read the main blocker to production was the interdepartmental bickering over who pays for it.  Bringing the entire operation under one department would likely reduce these problems.

Offline iamlucky13

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Re: Good news on the Plutonium production issue
« Reply #47 on: 03/22/2013 02:50 AM »
I do not see anything changing until either NASA is given the right to produce its own Pu-238 or a commercial operation is able to supply it.

Neither will ever happen. As Jim points out, NASA doesn't *want* the former idea; furthermore, the latter is stupid and dangerous.

Sorry to break it to you, but there are a number of companies that sell isotopes that are produced in commercial reactors for uses in various industries including nuclear medicine.  That is not to mention the hundreds of research reactors at universities where they produce isotopes for their own experiments.

Not hundreds. 28. And many of them extremely small.
http://www.trtr.org/Links/TRTR_December.html

None of them are producing 25,000 Curies per year of single isotopes, especially not so much isolated material.

Research supply companies like United Nuclear don't run their own reactors. They buy and repackage isotopes. United Nuclear sells samples in the microCurie range. They get theirs from Oak Ridge, which is a DOE facility, and where the Pu-238 is being produced.

Most of the medical facilities in the US buy their isotopes from the Canadian government, which owns the Chalk River reactor.

Offline Jim

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Re: Good news on the Plutonium production issue
« Reply #48 on: 03/22/2013 04:54 AM »
Bringing the entire operation under one department would likely reduce these problems.

It is, under DOE.

Offline baldusi

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Re: Good news on the Plutonium production issue
« Reply #49 on: 03/25/2013 04:54 PM »
Don't you need centrifuges to separate the Pu-238 from the original material (probably americum?). Couldn't they use centrifuges to separate the Pu238 from the lead in the old stock?
BTW, if they do need centrifuges I seriously doubt any gvt in the world would allow a pure commercial production.

Offline Lar

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Re: Good news on the Plutonium production issue
« Reply #50 on: 03/25/2013 05:19 PM »
Don't you need centrifuges to separate the Pu-238 from the original material (probably americum?). Couldn't they use centrifuges to separate the Pu238 from the lead in the old stock?
BTW, if they do need centrifuges I seriously doubt any gvt in the world would allow a pure commercial production.

While this might be technically possible, I suspect that the effort/equipment/cost to centrifuge is far higher than the cost to just mix two things together...
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Offline kevin-rf

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Re: Good news on the Plutonium production issue
« Reply #51 on: 03/25/2013 05:34 PM »
I suspect you only need centrifuges if you are separating isotopes of the same element. All other separations are chemistry.

I bet it is more an issue of dissolving and reprocessing Pu238 which is highly radioactive that makes removing the lead prohibitive. Just yucky chemistry in a very radio active environment of a product that produces a fair amount of heat.   
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Offline savuporo

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Re: Good news on the Plutonium production issue
« Reply #52 on: 12/09/2013 09:10 PM »
The other Pu-238 thread inexplicably died.
So thats the next best update thread for this  :

http://www.planetary.org/blogs/guest-blogs/van-kane/20131208-the-asrg-cancellation-in-context.html

I think its slightly insane that anyone ever considers a solar powered probe out at Saturn, or even Jupiter for that matter.
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Offline Mike_1179

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Re: Good news on the Plutonium production issue
« Reply #53 on: 12/10/2013 02:21 AM »
The other Pu-238 thread inexplicably died.
So thats the next best update thread for this  :

http://www.planetary.org/blogs/guest-blogs/van-kane/20131208-the-asrg-cancellation-in-context.html

I think its slightly insane that anyone ever considers a solar powered probe out at Saturn, or even Jupiter for that matter.

Juno is making it work.  It's not a ton of power to work with (around 450-ish watts if I remember) but its in the same neighborhood as the Galileo orbiter had at Jupiter using an RTG - I think that was in the mid 500's.

Offline NovaSilisko

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Re: Good news on the Plutonium production issue
« Reply #54 on: 12/10/2013 03:28 AM »
The other Pu-238 thread inexplicably died.
So thats the next best update thread for this  :

http://www.planetary.org/blogs/guest-blogs/van-kane/20131208-the-asrg-cancellation-in-context.html

I think its slightly insane that anyone ever considers a solar powered probe out at Saturn, or even Jupiter for that matter.

Juno is making it work.  It's not a ton of power to work with (around 450-ish watts if I remember) but its in the same neighborhood as the Galileo orbiter had at Jupiter using an RTG - I think that was in the mid 500's.

From what I understand, Juno has to expend almost half of its electricity to power heaters, whereas Galileo had the advantage of being able to use heat directly from the RTGs, without using any of the power they produce (or perhaps a small amount, to heat areas more distant from the RTG? someone who knows please correct me)
« Last Edit: 12/10/2013 03:30 AM by NovaSilisko »

Offline Jim

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Re: Good news on the Plutonium production issue
« Reply #55 on: 12/10/2013 03:37 AM »


Juno is making it work.  It's not a ton of power to work with (around 450-ish watts if I remember) but its in the same neighborhood as the Galileo orbiter had at Jupiter using an RTG - I think that was in the mid 500's.


Yeah, with instruments with low data rates or short data takes.
Juno is an exception, especially since it has no real imaging instruments.

Offline RonM

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Re: Good news on the Plutonium production issue
« Reply #56 on: 12/10/2013 04:04 AM »
The other Pu-238 thread inexplicably died.
So thats the next best update thread for this  :

http://www.planetary.org/blogs/guest-blogs/van-kane/20131208-the-asrg-cancellation-in-context.html

I think its slightly insane that anyone ever considers a solar powered probe out at Saturn, or even Jupiter for that matter.

Juno is making it work.  It's not a ton of power to work with (around 450-ish watts if I remember) but its in the same neighborhood as the Galileo orbiter had at Jupiter using an RTG - I think that was in the mid 500's.

From what I understand, Juno has to expend almost half of its electricity to power heaters, whereas Galileo had the advantage of being able to use heat directly from the RTGs, without using any of the power they produce (or perhaps a small amount, to heat areas more distant from the RTG? someone who knows please correct me)

Galileo had two RTGs mounted on booms extending from the spacecraft. They would not have been able to effectively heat the vehicle.

Juno is probably having to use more power to heat the craft because of the batteries.

The big difference is that Galileo operated around Jupiter for eight years and Juno will only last a little over a year. Juno's solar panels and batteries will not be able to survive the harsh environment like RTGs. Then again, if we had to wait on plutonium production, we wouldn't have the Juno mission.

Offline Mike_1179

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Re: Good news on the Plutonium production issue
« Reply #57 on: 12/10/2013 04:13 AM »


Juno is making it work.  It's not a ton of power to work with (around 450-ish watts if I remember) but its in the same neighborhood as the Galileo orbiter had at Jupiter using an RTG - I think that was in the mid 500's.


Yeah, with instruments with low data rates or short data takes.
Juno is an exception, especially since it has no real imaging instruments.

Good point.  There's probably also a mass penalty for large solar arrays instead of an RTG as well, so there are sacrifices to be made.   Dawn is also out beyond Mars using solar panels only as well, so they do have their place, based on what the mission needs. 

Offline akula2

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Re: Good news on the Plutonium production issue
« Reply #58 on: 12/20/2013 01:11 PM »
How long it takes to research, design and develop a RTG? 3-5 years?
How much $ might go into this entire effort? Few hundred million? or 2-3 Billion?  :o

We are using Thorium Nuclear Reactors to generate power. How much feasible to make Thorium RTG?

Estimated world thorium resources in tonnes:

India     846,000
Turkey     744,000
Brazil     606,000
Australia     521,000
USA     434,000



Offline kevin-rf

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Re: Good news on the Plutonium production issue
« Reply #59 on: 12/20/2013 01:28 PM »
RTG's do not work the same as reactors. They work off the heat generated by decay of radio isotopes with short half lives. Thorium 232 with a half life of 14.05 billion years does not meet that requirement. You can not get enough heat out of natural decay. 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 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.
« Last Edit: 12/20/2013 01:31 PM by kevin-rf »
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