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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 29, 2014 11:10 pm 
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Getting back on track, does anyone know how much Pu239 would be required to start the ORNL DMSR? Similar to the amount of U235 required??


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 30, 2014 5:22 am 
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Lindsay wrote:
Getting back on track, does anyone know how much Pu239 would be required to start the ORNL DMSR? Similar to the amount of U235 required??


It has a bigger thermal neutron fission cross section, so you'd need a bit less I think. Maybe 20-30% less? But, it also absorbs more neutrons than U235, so you need more makeup fuel if I should speculate.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 30, 2014 5:39 am 
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Also, if the U235 comes as LEU it has >80% U238 so then the advantage for Pu will be much bigger (even if RGPu).


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 30, 2014 11:21 am 
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Remember if you are talking about reactor grade plutonium to only count the Pu-239 and the remaining Pu241. As a rough guess I would expect that you are looking to keep the probability of fission constant so (quantity of U-235)*(U-235 fission cross-section) / (total absorption cross-section) ~= {(quantity of Pu-239) * (Pu-239 fission cross-section) + (quantity of Pu-241) * (Pu-241 fission cross-section)} / (total absorption cross-section)

With U-235 you have a significant fertile in the U-238 so that weighs on the total absorption cross-section. If you are looking to breed a significant portion of your fuel then the fertile cross-section should be similar to the fission cross-section so you use 1 neutron to fission, some to losses (including absorption by Pu-239 without fission), and the rest to fertile->fissile. You hope the rest turns out to be approaching 1.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 30, 2014 12:33 pm 
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robert.hargraves wrote:
Now that the Savannah River Site MOX fabrication facility is shut down, how will the US meet its treaty obligations to dispose of at least 34 tons of weapons-grade plutonium?

http://nuclearstreet.com/nuclear_power_ ... 9kqoPk7tEF
Quote:
Embattled SRS MOX Project Gains Support in Washington
Nuclear Street News Team Tue, Jul 29 2014

Political support in Congress is coalescing around funding to continue construction of the overbudget MOX fuel plant at the Savanah River Site, despite the Obama administration's plan to close it.

SRS MOX project. Source: DOEAppropriations bills in both the House and Senate include roughly $345 million for construction next year, and an earlier agreement between South Carolina politicians and the Department of Energy extended work at the plant through the end of September. On Monday, the Augusta Chronicle reported that Energy Secretary Ernest Moniz instructed the plant's contractors to draw up plans for various levels of funding. At an event with Moniz at the Savannah River Site, members of the South Carolina congressional delegation confirmed funding would likely be available through next year.

The project employs 1,800 people and would eventually provide a disposal method for surplus plutonium, as outlined in an arms reduction agreement with Russia. The plant is 60 percent complete and has drawn the scrutiny of the DOE inspector general's office, which reported the project is three years behind schedule and saw its budget increase from $2.9 billion to $7.7 billion over five years.


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 Post subject: Re: Plutonium dispostion
PostPosted: Jul 31, 2014 12:04 am 
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http://dae.nic.in/writereaddata/.pdf_38
U-Pu MOX in LWR is a concept overtaken by more advanced thinking. Th-Pu MOX is more suitable for higher burn up. Refer to pages 6-8 of the reference link.


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 Post subject: Re: Plutonium dispostion
PostPosted: Feb 13, 2016 8:52 am 
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Interesting news about the MOX Fuel Fabrication Facility in South Carolina this week:

http://www.world-nuclear-news.org/UF-Ob ... 21601.html

The Obama administration is going to kill the MOX project at the Savannah River Site.

However, the following sentences caught my eye:

"Russia and the USA have each launched the construction of MOX plants. The Americans have already spent $7.7 billion and eight years on building theirs, but at the start of [last week] the US Congress announced that, with no end in sight, they are halting construction. We also have a MOX facility, which we built in two-and-a-half years for RUB9 billion ($136 million). The plant is in operation," Kirienko said.

This is scandalous, if the Russian information is correct. The MOX facility in South Carlina has already cost US$ 7.7 bn. and is not yet complete. The Russians have built a similar, but completed MOX facility for US$ 136 mn. in 2.5 years.

I can not get my head around this: how does the U.S. manage to spend such an amount on a facility that the Russians have built for a price that is at least 50 times less ?


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 Post subject: Re: Plutonium dispostion
PostPosted: Feb 13, 2016 5:18 pm 
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Dear Camiel,

if I see it from the technical point of view...the military Pu is in a metallic state..it is to necessary to grind it to a powder...to oxidize it to PuO2 ...mix it with UO2 powder....a yearly capacity of 34to Pu/yr. ..about 110Kg/day or 6 Kg/hr If it is not a nuclear site I would estimate the costs to < 50 Mio.


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 Post subject: Re: Plutonium dispostion
PostPosted: Feb 13, 2016 6:40 pm 
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camiel wrote:
I can not get my head around this: how does the U.S. manage to spend such an amount on a facility that the Russians have built for a price that is at least 50 times less ?

I suspect that Russia does not have equivalent agencies to our OSHA, EPA, and NRC. I suspect that Russians are reluctant to protest the building of a facility that handles nuclear material like US citizens are known to do. We respect the freedom of expression here, unlike in Russia where people that advocate for same sex marriage can be imprisoned. I have to wonder, how does Russia treat nuclear power protestors? If Russia can claim there are no homosexuals in their nation then I expect them to also claim everyone supports the Russian nuclear power industry.

I don't know if bureaucracy and protesters can drive the cost of a nuclear facility up to 50x what it might in a less free nation but I have no doubt that it has an effect.

I can recall that US facilities that handled radioactive material during World War II were built very quickly and cheaply. There were also cases of the children of the workers from those facilities showing health problems from heavy metal poisoning and radiation exposure because the workers would go home with radioactive dust on their clothes.

Again, it's unlikely that an overabundance of caution that we have in the US towards our health, especially when it comes to nuclear safety, can drive up costs like we see. I suspect that political pressures also come in since every US senator is going to want to make sure a federally regulated industry, like nuclear power, will end up in their state.

I've said this before and I'll keep saying it, I believe that every state in the USA has the authority to bypass federal nuclear regulations and regulate nuclear power as it sees fit within its borders. I believe that such cost overruns would be much less likely if a state regulated the industry on its own, and therefore nuclear power would be undoubtedly more profitable than any other energy source we have now. If nations with as few as 3 million people can operate a nuclear power plant then I'd think even a state as small as Iowa could do so without federal government interference, that would include about half of the states. If that sounds like too much to ask for then what about a state with a population comparable to the UAE? They have about 9 million people and a nuclear power program. If the UAE can sustain a nuclear power program then so should about 1/4 of the states in the USA that have a population above 9 million.

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Disclaimer: I am an engineer but not a nuclear engineer, mechanical engineer, chemical engineer, or industrial engineer. My education included electrical, computer, and software engineering.


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 Post subject: Re: Plutonium dispostion
PostPosted: Feb 14, 2016 12:26 am 
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Russian, Chinese and Korean reactors are lowest cost as things stand. It might be best to outsource the use of plutonium as thorium-plutonium mixed oxide in Russia, China or India. You can get more energy from same fissile due to in situ irradiation of thorium and burning of U-233.
file:///C:/Users/sony/Downloads/glbrchth.pdf
Norwegians are trying out such a fuel.


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 Post subject: Re: Plutonium dispostion
PostPosted: Feb 14, 2016 2:16 am 
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camiel wrote:
Interesting news about the MOX Fuel Fabrication Facility in South Carolina this week:

http://www.world-nuclear-news.org/UF-Ob ... 21601.html

The Obama administration is going to kill the MOX project at the Savannah River Site.


Here's something that caught my eye:
Quote:
Areva noted that, according to their Plutonium Management and Disposition Agreement, the USA and Russia must change their surplus plutonium at the isotopic level to render the nuclear material unattractive for weapons use.


I read that to mean that the Pu-239 must be blended down with enough Pu-238 (decay heat hazard) and/or Pu-240 (spontaneous fission hazard) to make it non-viable for use in a weapon. With Pu-238 being extremely valuable as RTG fuel this means down blending with Pu-240. If I'm reading the properties of Pu-242 correctly then it appears blending with Pu-242 would be bad for use as fuel since it's a neutron poison, and that's assuming we have any to blend. Again, assuming I'm reading the properties of Pu isotopes correctly it appears that isotopes other than Pu-240 are short lived enough and/or difficult enough to produce that we'd have very little of it.

I have a question, how much Pu-240 do we have to down blend the weapons grade stuff to reactor grade?

(I also have another question not specifically related to this issue, would high purity Pu-240 be considered "depleted plutonium", "enriched plutonium", or would either term be non-sensical? The terms have well defined terms when it comes to uranium but do they also apply to plutonium?)

jagdish wrote:
Russian, Chinese and Korean reactors are lowest cost as things stand. It might be best to outsource the use of plutonium as thorium-plutonium mixed oxide in Russia, China or India. You can get more energy from same fissile due to in situ irradiation of thorium and burning of U-233.


Blending weapon grade plutonium with thorium does not seem to me to meet the treaty requirements as I understand them. Assuming it would we would need a facility capable of doing this, and the issue at hand is the facility capable of producing this mixed oxide fuel is under threat of not being completed as promised. I'd also assume that there are political issues in shipping even demilitarized plutonium outside our borders. Assuming that we can blend plutonium with thorium into fuel we'd also have to find a reactor operator comfortable with using this as a fuel. Which gets to this...

jagdish wrote:
file:///C:/Users/sony/Downloads/glbrchth.pdf
Norwegians are trying out such a fuel.


The link is broken but I assume it talks about using this mixed Pu-Th in a solid fuel water cooled reactor. If the Norwegians can build such a reactor then so can we. If the problem is getting rid of this weapon grade plutonium at a rate required to meet a treaty obligation, the federal government is willing to spend billions of dollars to do so, and the treaty allows for the use of the plutonium as fuel for energy production then I say we use it to make energy to offset the cost to dispose of the fuel.

It seems the NRC is essentially unwilling to license a civilian reactor that deviates from a water cooled solid fuel reactor. It also seems like the DoD is perfectly willing to use nuclear reactors for powering US Navy vessels and military bases. The best solution that I see in solving this issue is to invest this billions of dollars the federal government is willing to spend on getting rid of this plutonium is to hand the money and plutonium to the DoD and instruct them to build as many plutonium burning power plants as they can to meet their energy needs and meet the nation's treaty obligations.

I don't know how many reactors the DoD wants or needs but if the option of military nuclear reactors is open to us with this treaty then I say we do it.

Of course we also have the option of the people in Congress and the White House to instruct the NRC to get their butts off their thumbs and invest this money that is set aside for disposal of plutonium and put it towards civilian nuclear power. This gets back to the original problem, the federal government is so dysfunctional that if they had to vote on what to eat for lunch they'd be deadlocked in a heated debate until all of them died of starvation.

This also gets back to what I stated in my previous post, I believe that the state governments should no longer allow the federal government to have a monopoly on the licensing of nuclear facilities. The states should assert their authority to license their own reactors and fuel processing plants. Thinking that the federal government will solve a problem they created sounds naive to me. State governments are not immune to the federal government's problem of political deadlock but at least we have 50 times as many chances of something useful getting done rather than placing all our faith in the federal government getting around to solving this.

We should not be even considering burying this plutonium or shipping it to other nations. What we should be doing is turning this material into fuel. Fossil fuels may be cheap now but they might not be in five years. We need to start building nuclear reactors now so that when (not if) fossil fuel prices go up again that we have reactors on line as a buffer to how much damage the rising cost of energy has on the economy.

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Disclaimer: I am an engineer but not a nuclear engineer, mechanical engineer, chemical engineer, or industrial engineer. My education included electrical, computer, and software engineering.


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 Post subject: Re: Plutonium dispostion
PostPosted: Feb 14, 2016 3:15 pm 
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By the time construction started in South Carolina Siemens finally scraped its MOX plant in Hanau, after several attempts to get an export license for the equipment. The building was sold to internet provider 1&1 which uses it as a data center.


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 Post subject: Re: Plutonium dispostion
PostPosted: Feb 17, 2016 9:42 pm 
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Kurt Sellner wrote:
I have a question, how much Pu-240 do we have to down blend the weapons grade stuff to reactor grade?

This may help:


Attachments:
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DoE-NNSA_WGPu-MOX_options.JPG [ 371.13 KiB | Viewed 2069 times ]
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 Post subject: Re: Plutonium dispostion
PostPosted: Feb 18, 2016 12:49 am 
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jaro wrote:
Kurt Sellner wrote:
I have a question, how much Pu-240 do we have to down blend the weapons grade stuff to reactor grade?

This may help:


Thanks, that chart is quite informative. What I noticed were three things. First, my suspicions on a rarity of Pu isotopes with atomic masses of 241 and greater does seem to be largely true. Second, if the claims of the unimaginable mass of spent fuel is true then we have plenty of Pu-240 to blend down weapons grade plutonium. Third, I now believe that the claims of the threats of weapons proliferation from reprocessing spent fuel is overblown. The quality of the plutonium from spent fuel is far from what one would need to produce weapons.

I did a quick Google search and I see that Pu-240 can capture a neutron to become Pu-241. Fission of Pu-241 produces about 2.9 neutrons. That tells me that a mix of Pu-239 and Pu-240 of nearly any ratio would be quite valuable as a nuclear fuel even if worthless for weapons. Unless I'm missing something important.

I won't even pretend that I know all the precautions that need to take place to process spent fuel and plutonium weapon cores to fluoride salts but it does look like the chemistry is pretty simple. Expose the material to fluorine gas and collect the salts it produces. Once you have a pile of salts the PuF and UF can be separated out, the isotopes mixed to meet treaty requirements and reactor fuel requirements. Put the PuF and UF in a DMSR in the necessary ratios and now you are burning plutonium. Sounds much easier than any MOX solid fuel processing.

Again, I may be missing an important detail.

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Disclaimer: I am an engineer but not a nuclear engineer, mechanical engineer, chemical engineer, or industrial engineer. My education included electrical, computer, and software engineering.


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 Post subject: Re: Plutonium dispostion
PostPosted: Feb 18, 2016 6:50 am 
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One can probably build a ~1kT device from reactor grade plutonium, but it would require advanced design techniques which would be a big risk for a first time builder.
But that is hardly the strategic weapon that proliferation is designed to prevent.


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