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PostPosted: Mar 03, 2010 10:26 am 
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Read over ORNL-5388 and see what conclusions you come to regarding permitted activities for proliferation.
The interpretation that >12% 233U is not permitted to exist anywhere I think is stricter than current regulations.
Certainly maintaining a strict <12% 233U everywhere at all times is a higher level of anti-proliferation and was the line taken by the DMSR but I think it is more strict than is required.

I think we agree that current regulations would forbid transport of clean 233U with greater than 12%.
However, I think the presence of intense radiation from fission products provides self-protection.
In Dr. Peterson's AHTR he exposes clean 233U pebbles to a neutron flux at the secure site prior to shipment.

Similarly, existing LWRs are allowed to have fuel inside the reactor that is only 3 months old. At that point the plutonium in the solid fuel is pretty close to pure 239Pu that would not be allowed in general. So from this I conclude that being inside the reactor provides a level of protection.

Proliferation concerns are graded based on multiple effects combined.
I have attached the paper sent by Dr. Peterson on proliferation guidelines.


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PostPosted: Mar 03, 2010 11:35 am 
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Lars wrote:
I have attached the paper sent by Dr. Peterson on proliferation guidelines.

Thanks -- interesting paper.

One curious aspect I noticed:

In the Fissile Material Type (MT) Proliferation Resistance Metric, HEU is graded as Very Low resistance, while LEU is graded Very High resistance.

That sounds fine, until you read that LEU is defined as "nominally 5% 235U".

Most LFTR discussion on this forum assumes LEU is up to 20% 235U.
Big difference !

Moreover, the paper's LEU definition would imply a corresponding "nominal" value of just 3% for 233U.


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PostPosted: Mar 03, 2010 2:07 pm 
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Lars wrote:
Read over ORNL-5388 and see what conclusions you come to regarding permitted activities for proliferation.
The interpretation that >12% 233U is not permitted to exist anywhere I think is stricter than current regulations.


I have yet to see where such a regulation exists. All that document talks about is the level of U-238 downblending required to be equivalent to 20% enriched uranium.


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PostPosted: Mar 03, 2010 2:59 pm 
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Lars, Jaro, Kirk, thank you. As a relative newby I have almost no understanding of the regulatory hurdles and in my reading on this forum there doesn't seem to much discussion on the subject. In the form of a question, is it worth setting up a new discussion area within Liquid-Halide Reactors to discuss Regulatory Issues?

There are some wonderful discussions here on different approaches and design options, but if those designs have no hope of meeting existing regulatory hurdles, I would think that would be worth better understanding the specific hurdle/s. Equally for those designs with the potential to meet regulatory requirements, that's a major plus worth noting. And beyond that there might be some channels for influencing regulation (he said extremely optimistically).


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PostPosted: Mar 03, 2010 4:53 pm 
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Kirk Sorensen wrote:
Lars wrote:
Read over ORNL-5388 and see what conclusions you come to regarding permitted activities for proliferation.
The interpretation that >12% 233U is not permitted to exist anywhere I think is stricter than current regulations.


I have yet to see where such a regulation exists. All that document talks about is the level of U-238 downblending required to be equivalent to 20% enriched uranium.



Reference:

http://www.iaea.org/Publications/Docume ... categ.html

With all kindly respect, your statement is not true.

The IAEA rules for fissile transport allows for self protection and physical form factor difficulty; a loophole!

It is possible to move small amounts of self protected U233 (2.4 % U232) around without an armed escort if the quantities are small (see enclosure below).

Note from the reference document: This categorization should be based on the potential risk of the material being used for a nuclear explosive device, which itself depends on: the type of material, e.g. plutonium, uranium; isotopic composition, i.e. content of fissile isotopes; physical and chemical form; degree of dilution; radiation level; and quantity;. For example:

In particular, the protection of nuclear material with a radiation level that exceeds 1 Gy/hr (100 rad/hr) at one meter unshielded, which is classified as Category I or II, may be reduced one category level below that determined by the fissile content of the material;

If the physical barrier is in the form of hot molten fluoride salt in which a small amount of pure U232/233 is greatly diluted, that should fit the requirement for both dilution and a physically restrictive form factor similar in principle to the TRISO fuel form that Per Peterson is relying on.

2 kilos of hot, radioactive, deluded U233 can be considered as type III nuclear materials.


Attachments:
Iaea ruel for U233.jpg
Iaea ruel for U233.jpg [ 30 KiB | Viewed 2254 times ]

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PostPosted: Mar 03, 2010 5:34 pm 
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Axil wrote:
Reference:

http://www.iaea.org/Publications/Docume ... categ.html

With all kindly respect, your statement is not true.

The IAEA rules for fissile transport allows for self protection and physical form factor difficulty; a loophole!

It is possible to move small amounts of self protected U233 (2.4 % U232) around without an armed escort if the quantities are small (see enclosure below).


That describes the category, not whether or not you can move it, nor whether you can use it. It's not like U-233 in relatively pure form is not legally allowed to exist.

You'll never get to 2.4% U-232. No way.


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PostPosted: Mar 03, 2010 5:46 pm 
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Kirk Sorensen wrote:
Axil wrote:
Reference:

http://www.iaea.org/Publications/Docume ... categ.html

With all kindly respect, your statement is not true.

The IAEA rules for fissile transport allows for self protection and physical form factor difficulty; a loophole!

It is possible to move small amounts of self protected U233 (2.4 % U232) around without an armed escort if the quantities are small (see enclosure below).


That describes the category, not whether or not you can move it, nor whether you can use it. It's not like U-233 in relatively pure form is not legally allowed to exist.

You'll never get to 2.4% U-232. No way.



From the reference as follows:

Quote:
Requirements for Category III Nuclear Material Transport

8.5.1. Advance notification to receiver

8.5.1.1. The shipper should give the receiver advance notification of the planned shipment specifying the mode of transport (road/rail/sea/air), the estimated time of arrival of the shipment and the exact point of hand-over if this is to be done at some intermediate point before the ultimate destination.

8.5.2. Provision of locks and seals

8.5.2.1. Where practicable, locks and seals should be applied to vehicles or freight containers.

8.5.3. Search of load vehicle

8.5.3.1. There should be a detailed search of the load vehicle prior to loading and shipment, to ensure that sabotage devices have not been implanted or that sabotage has not been initiated.

8.5.4. Measures after shipment

8.5.4.1. The receiver should notify the shipper of the arrival of the shipment immediately or of non-arrival within a reasonable interval after the estimated time of arrival at the destination.


Notice: No guns and helicopters required.

Any type of breeder (source of neutrons) can generate pure U232 form pure Th230 in any desired amount.

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PostPosted: Mar 03, 2010 5:53 pm 
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The only description I found there relating to 233U made no reference to the enrichment level.
So I presume this defines what level you get with pure 233U (and by speculation anything above 12%).
Since our quantity will be far more than 2kG this is the arena of interest to us.

Unirradiated puts it into category I.

Irradiated puts it into category II - same as fresh 10-20%LEU.

So from an international transport perspective only (your government may have stricter rules) we can ship any enrichment of 233U that has enough fission products to be radiating at 100 rad/hr with the same hassles as shipping 10-20%LEU.

Oddly, the recommend (but do not insist) on the same level of protection for thorium and depleted uranium - but there is a lower level requirement for <10% LEU. Very odd.


Note that these rules specify nothing about what goes on inside the reactor core.


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PostPosted: Mar 03, 2010 5:54 pm 
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Axil wrote:

Any type of breeder (source of neutrons) can generate pure U232 form pure Th230 in any desired amount.

So long as you have sufficient funds and time.


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PostPosted: Mar 03, 2010 6:15 pm 
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Lars wrote:
The only description I found there relating to 233U made no reference to the enrichment level.
So I presume this defines what level you get with pure 233U (and by speculation anything above 12%).
Since our quantity will be far more than 2kG this is the arena of interest to us.

Unirradiated puts it into category I.

Irradiated puts it into category II - same as fresh 10-20%LEU.

So from an international transport perspective only (your government may have stricter rules) we can ship any enrichment of 233U that has enough fission products to be radiating at 100 rad/hr with the same hassles as shipping 10-20%LEU.

Oddly, the recommend (but do not insist) on the same level of protection for thorium and depleted uranium - but there is a lower level requirement for <10% LEU. Very odd.


Note that these rules specify nothing about what goes on inside the reactor core.



Quote:
Since our quantity will be far more than 2kG this is the arena of interest to us.


True. At startup, to transport a few tons of pure U233, you need guns and helicopters.

Quote:
8.3. Requirements for Category I Nuclear Material Related to the Mode of Transport

8.3.1. General

8.3.1.1. In addition to the requirements mentioned above, there should be further detailed requirements for Category I material related to the mode of transport as set out below.

8.3.2. Shipment by road

8.3.2.1. Designated load vehicle(s) should be used exclusively for each consignment and should preferably be specially designed to resist attack and equipped with a vehicle disabling device. Each load vehicle should carry a guard for that vehicle.

8.3.2.2 Each load vehicle should be accompanied by at least one vehicle manned by one or more guards.

8.3.2.3 If the transport cannot be completed in one day, prior arrangements should be made for overnight stay at a stopping place approved by the competent authority. During such overnight stays the load vehicle should be immobilized or parked in a locked and guarded building or compound.

8.3.2.4 There should be two-way communication between the load vehicle and the escort vehicle in addition to communication between these vehicles and the transport control centre.

8.3.3. Shipment by rail

8.3.3.1 Shipment should be in a freight train in an exclusive use wagon.

8.3.3.2 Accompanying guards should travel in the carriage nearest to the shipment.

8.3.4. Shipment by sea

8.3.4.1. Shipment should be carried out by a dedicated transport ship.

8.3.4.2. The shipment should be placed in a secure compartment or container which is locked and sealed.

8.3.5. Shipment by air

8.3.5.1 Shipment should be by aircraft designated for cargo only and for which the nuclear material is its sole cargo.


To supplement the slightly sub breakeven operational Lftr with monthly additional fissile in the appropriate physical fuel form factor requires minimal protection during transport under IAEA rules as I interpret them.

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PostPosted: Mar 03, 2010 7:19 pm 
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Lars wrote:
Axil wrote:

Any type of breeder (source of neutrons) can generate pure U232 form pure Th230 in any desired amount.

So long as you have sufficient funds and time.

.....and where does the Th230 come from ??
....is there ANY amount of this stuff, in pure form, in existence anywhere on earth ?
....why do you assume "any desired amount" ?
....is this the same as assuming regulations limited to just the desired amount ?
....or how about MSR development funding in "any desired amount" ?


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PostPosted: Mar 03, 2010 8:24 pm 
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jaro wrote:
Lars wrote:
Axil wrote:

Any type of breeder (source of neutrons) can generate pure U232 form pure Th230 in any desired amount.

So long as you have sufficient funds and time.

.....and where does the Th230 come from ??
....is there ANY amount of this stuff, in pure form, in existence anywhere on earth ?
....why do you assume "any desired amount" ?
....is this the same as assuming regulations limited to just the desired amount ?
....or how about MSR development funding in "any desired amount" ?


Thanks for your reiteration of this topic, I need the practice.

Quote:
.....and where does the Th230 come from ??
....is there ANY amount of this stuff, in pure form, in existence anywhere on earth ?


To refresh your memory once again see the following:

viewtopic.php?f=6&t=185&start=15&st=0&sk=t&sd=a

We discussed this before at the following:

viewtopic.php?p=28178#p28178

Quote:
....why do you assume "any desired amount" ?

....is this the same as assuming regulations limited to just the desired amount ?


If a mode of U232 breeding is put into place that can produce pure U232, then U232 can provide denaturing at any level that the IAEA desires or whoever else defines as safe. If a goodly supply of pure U232 is on hand, simple proportional mixing of U232 into U233 would provide the desired denaturing assay level whatever it turns out to be.

Quote:
....or how about MSR development funding in "any desired amount" ?


If an Lftr (i.e. two fluid) can breed U233 using Th232, then the same design can breed U232 from Th230 with little or no additional design cost; if that is what you mean here.

In general, if a pure thorium fuel cycle comes into existence, some reactor design will need to breed U233, that same design can breed pure U232.

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PostPosted: Mar 03, 2010 9:01 pm 
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Axil wrote:
Quote:
.....and where does the Th230 come from ??
....is there ANY amount of this stuff, in pure form, in existence anywhere on earth ?


To refresh your memory once again see the following:

viewtopic.php?f=6&t=185&start=15&st=0&sk=t&sd=a

We discussed this before at the following:

viewtopic.php?p=28178#p28178

From the old forum post,
Kirk Sorensen wrote:
thorium-230 (commonly referred to as ionium) ......is a daughter product of uranium-238, it is found in uranium ores at secular equilibrium in a concentration of 18.4 parts per million parts of uranium.


....which basically implies that the Th/U233 fuel cycle is made dependent on uranium mining for its "proliferation resistance".

Long term, we're looking at mining uranium at 300ppm or less -- that's 61 parts per billion Th230.

You can't be serious !
Kirk Sorensen wrote:
You'll never get to 2.4% U-232. No way.

Agree !


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PostPosted: Mar 03, 2010 9:56 pm 
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jaro wrote:
Axil wrote:
Quote:
.....and where does the Th230 come from ??
....is there ANY amount of this stuff, in pure form, in existence anywhere on earth ?


To refresh your memory once again see the following:

viewtopic.php?f=6&t=185&start=15&st=0&sk=t&sd=a

We discussed this before at the following:

viewtopic.php?p=28178#p28178

From the old forum post,
Kirk Sorensen wrote:
thorium-230 (commonly referred to as ionium) ......is a daughter product of uranium-238, it is found in uranium ores at secular equilibrium in a concentration of 18.4 parts per million parts of uranium.


....which basically implies that the Th/U233 fuel cycle is made dependent on uranium mining for its "proliferation resistance".

Long term, we're looking at mining uranium at 300ppm or less -- that's 61 parts per billion Th230.

You can't be serious !
Kirk Sorensen wrote:
You'll never get to 2.4% U-232. No way.

Agree !



Quote:
Agree !


Not quite yet.

Reference:

http://pintassilgo2.ipen.br/biblioteca/2006/11539.pdf

When Uranium mining ends, there is always Phosphate. Phosphate waste contains decent concentrations of 230Th in equilibrium (1508 +- 57 Bq /kg ), and there is endless tons of phosphate waste accumulated around the world with more tons produced daily in perpetuity.

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PostPosted: Mar 03, 2010 10:38 pm 
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jaro wrote:
thorium-230 (commonly referred to as ionium) ......is a daughter product of uranium-238, it is found in uranium ores at secular equilibrium in a concentration of 18.4 parts per million parts of uranium.
....which basically implies that the Th/U233 fuel cycle is made dependent on uranium mining for its "proliferation resistance".

Long term, we're looking at mining uranium at 300ppm or less -- that's 61 parts per billion Th230.

You can't be serious !
Kirk Sorensen wrote:
You'll never get to 2.4% U-232. No way.

Agree !

Slipped a digit. That is 6 parts per billion.
Just for fun let do some calculations:
Suppose we are fissioning 1 tonne u233 per year and have 2.4% u232.
Since the (fission + capture) cross-section of u232 is around the same as the fission cross-section of u233 we will be losing 1000kg * 2.4% or 24kg u232 per year.
Let's be optimistic and assume all of the Th230 and all of the Pa231 capture neutrons with no fissions or decay.
So we need 24kg Th230 per year.
At 6 ppbillion this means we need to sort through 4 million tonnes of ore per year to get your Th230 for a single 1 GWe reactor (if your extraction process is perfect).
This is 6 times more ore than an LWR has to wade through.
So could we do 240ppm - a hundred fold less - yes for this much of the calculations. But we still would need to understand how hard it is to separate the Th230 from the ore and what the concentration of Th230 is compared to Th232 in that ore.


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