Recovering sea-water uranium - what advantage Fusion?

[Andrew Mason]

Apparently efforts to recover U from seawater were abandoned in the 1970s when studies concluded that it would cost about $1400 / lb. At the time, the spot price of U was about $40/lb.

If the cost of recovering U from sea water can be brought down to $100 a pound, (current price is around $62 US/lb), there would appear to be a virtually unlimited supply of U for nuclear reactors. Work on U recovery from seawater in Japan indicates that the cost may be approaching this level. Given the huge enrichment cost, the actual cost of U is a pretty small part of the total fuel cost.

Question:

So what would the advantage be of fusion? In strictly economic terms, the enormous research and development cost for a fusion reactor would seem to be better directed at recovering U from seawater and using the U in seawater instead of the H for energy.

AM

 

[berkeman]

Yeah, not many people seem to realize that fusion has nuclear waste as well (less, but still non-zero). The main advantae of fusion versus fission seems to be that a reactor meltdown stops on its own with fusion. But the disadvantage so far with fusion seems to be that the easier RX to achieve are plenty dirty. But if we could sustain the cleaner fusion RX...

 

[Andrew Mason]

Yeah, not many people seem to realize that fusion has nuclear waste as well (less, but still non-zero). The main advantae of fusion versus fission seems to be that a reactor meltdown stops on its own with fusion. But the disadvantage so far with fusion seems to be that the easier RX to achieve are plenty dirty. But if we could sustain the cleaner fusion RX...

I have a feeling that if the amount of research effort that has been put into fusion had been applied to making fission technology safe (as well as addressing the troubling security issues) we could have solved these problems by now. The main problem with fission is keeping enriched uranium or fissionable plutonium, as well as the highly radioactive fission waste, away from terrorists and rogue nations.

If U can be mined from seawater, we have a potentially serious international problem. I think we would do well to address this issue now before the technology starts proliferating uncontrollably.

AM

 

[Morbius]

So what would the advantage be of fusion? In strictly economic terms, the enormous research and development cost for a fusion reactor would seem to be better directed at recovering U from seawater and using the U in seawater instead of the H for energy.

Andrew,

Deuterium is even MORE plentiful in seawater than is Uranium.

Deuterium has an abundance of about 0.015% relative to all Hydrogen.
Water is 2/18 or about 11% Hydrogen.

Therefore water is about 0.0000167 Deuterium = 1.67e-5 Deuterium or
16,700 parts per billion. Uranium is about 3 parts per billion in seawater,
and the fissile U-235 is 0.7% of that.

Additionally, you get more energy per unit mass in fusion than in fission.
Fission gives you about 1 MeV / amu. Fusion gives you about 3.5 MeV/amu.

So the fusion energy content of the Deuterium in seawater represents
almost 3 MILLION TIMES as much energy as the fission energy content
of the U-235!

THAT's why it's worth going after the fusion technology.

Dr. Gregory Greenman
Physicist

 

[Morbius]

I have a feeling that if the amount of research effort that has been put into fusion had been applied to making fission technology safe (as well as addressing the troubling security issues) we could have solved these problems by now.

Andrew,

Those problems are essentially solved with "inherently safe" or
"passively safe" reactors such as Argonne's Integral Fast Reactor or IFR:

http://www.pbs.org/wgbh/pages/frontline/shows/reaction/interviews/till.html

The IFR can benignly handle accident conditions; and is proliferation resistant as
Dr. Till explained. Too bad President Clinton canceled it.

The main problem with fission is keeping enriched uranium or fissionable plutonium, as well as the highly radioactive fission waste, away from terrorists and rouge nations.

If a rogue nation is bent on developing nuclear weapons, they can do
that without nuclear power or help from Western technology.

At the start of the Gulf War in 1991, Iraq was only about a few months
away from having nuclear weapons; all done with indigenously developed
technology and resources. See the article by Dr. David Kay, USA's chief
nuclear weapons inspector, and Dr. Jay Davis, then Associate Director
of Lawrence Livermore National Laboratory beginning on page 20 of the
July 1992 issue of "Physics Today".

If U can be mined from seawater, we have a potentially serious international problem. I think we would do well to address this issue now before the technology starts proliferating uncontrollably.

Uranium is one of the most uniformly distributed elements in the Earth's
crust. ANY nation has sufficient Uranium in the ground within its borders
to make nuclear weapons. They just have to dig it up - they don't need
seawater.

The main hurdle that the world has relied on is the difficulty of obtaining
enrichment technology. That hurdle is there for seawater uranium too.

However, a determined nation, like Iraq and Iran; can overcome that
hurdle.

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

Additionally, you get more energy per unit mass in fusion than in fission.
Fission gives you about 1 MeV / amu. Fusion gives you about 3.5 MeV/amu.

Gregory,

There are an estimated 5 billion tonnes of U in sea-water. So does it really matter if fusion gives more energy?

We have only used 170,000 Tonnes of U in all reactors in the world to date. So even a million tonnes represents about a hundred years of supply. A billion tonnes represents tens of thousands of years supply. There is also more Thorium than U in sea water. So there is another couple of hundred thousand years worth of supply. And that does not even touch the U in granite, coal etc.

Andrew,

Those problems are essentially solved with "inherently safe" or
"passively safe" reactors such as Argonne's Integral Fast Reactor or IFR:

http://www.pbs.org/wgbh/pages/frontline/shows/reaction/interviews/till.html

The IFR can benignly handle accident conditions; and is proliferation resistant as
Dr. Till explained. Too bad President Clinton canceled it.

Did he give a reason for cancelling it?

If a rogue nation is bent on developing nuclear weapons, they can do
that without nuclear power or help from Western technology.

At the start of the Gulf War in 1991, Iraq was only about a few months
away from having nuclear weapons; all done with indigenously developed
technology and resources. See the article by Dr. David Kay, USA's chief
nuclear weapons inspector, and Dr. Jay Davis, then Associate Director
of Lawrence Livermore National Laboratory beginning on page 20 of the
July 1992 issue of "Physics Today".

Uranium is one of the most uniformly distributed elements in the Earth's
crust. ANY nation has sufficient Uranium in the ground within its borders
to make nuclear weapons. They just have to dig it up - they don't need
seawater.

The main hurdle that the world has relied on is the difficulty of obtaining
enrichment technology. That hurdle is there for seawater uranium too.

However, a determined nation, like Iraq and Iran; can overcome that
hurdle.

All good points. But doesn't that mean we just have to start now by setting up a world system for controlling mining and particularly the enrichment of U? If we say it can't be done I think we are conceding that humanity will end up with a nuclear catastrophe. All we have to do first is establish world peace... then it should be easy to control U.

AM

 

[Morbius]

Gregory,

There are an estimated 5 billion tonnes of U in sea-water. So does it really matter if fusion gives more energy?

Yes - but extracting that 5 billion tonnes requires running the ENTIRE volume
of the ocean through your extraction facility to recover all that.

Another way of looking at it, is for a given amount of energy; you only
have to process 1/3,000,000 of the amount of water for fusion as you do
for fission from seawater uranium.

Did he give a reason for cancelling it?

Yes - it was a campaign promise he made to the anti-nukes that
supported his election.

All good points. But doesn't that mean we just have to start now by setting up a world system for controlling mining and particularly the enrichment of U? If we say it can't be done I think we are conceding that humanity will end up with a nuclear catastrophe.

That's what the NPT - the Nuclear Non-Proliferation Treaty is all about.
You get nations to agree not to pursue a path to nuclear weapons.

The problem is ENFORCEMENT! We have cases like Iraq, Iran, and
North Korea that were found to be CHEATING on their treaty obligations.
What did the United Nations which oversees the treaty do?

In a word; NOTHING! There were no downsides for previous violators;
so why should any nation abide by the treaty?

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

Those problems are essentially solved with "inherently safe" or
"passively safe" reactors such as Argonne's Integral Fast Reactor or IFR:

http://www.pbs.org/wgbh/pages/frontline/shows/reaction/interviews/till.html

The IFR can benignly handle accident conditions; and is proliferation resistant as
Dr. Till explained. Too bad President Clinton canceled it.

Thanks very much for the link on the IFR. After further reading on this reactor it is apparent that the politicians may not have fully understood the potential of this technology.

The most remarkable feature of the IFR seems to be its ability to run on its original fuel for decades by reprocessing and reusing it. This also has the advantage of eliminating long term waste storage. Its design also made it very difficult and very unlikely for anyone to make a nuclear weapon out of the fuel.

It occurred to me that Clinton may have killed it at the behest of the Uranium mining industry. The IFR would have put them all out of business.

AM

 

[Morbius]

Thanks very much for the link on the IFR. After further reading on this reactor it is apparent that the politicians may not have fully understood the potential of this technology.
It occurred to me that Clinton may have killed it at the behest of the Uranium mining industry. The IFR would have put them all out of business.

Andrew,

The potential of the IFR was made VERY CLEAR to government officials by my
former collegues at Argonne like Dr. Till. After years of research and testing,
they had a reactor design that "inherently safe", proliferation resistant, and
could burn-up long lived nuclear waste. One would think that would be an
easy sell. However, they ran into a "buzz-saw"; one of the most anti-nuclear
Administrations to come to power in Washington. The Clinton Administration
with Al Gore running energy and environmental policy; just didn't want to hear
about it.

For example, a very respected government scientist, Dr. William J. Happer;
suggested that measurements be made of the ozone hole problem to see if
it was as big a problem as had been claimed. That didn't sit well with Al Gore;
and Dr. Happer was promptly fired.

DOE Secretary Hazel O'Leary announced that LLNL would be shutdown; a
decision she later reversed when LLNL scientists went along with the
Administration's policy vis-a-vis the CTBT. If the scientists didn't
"toe the line" in the Clinton Administration; they were silenced.

It wasn't the uranium mining industry.

Bill Clinton and Al Gore CAMPAIGNED on the fact that federal monies were given to
national labs to work on nuclear programs. They promised to put an end to that
practice and shutdown research on nuclear power. That's what they did - and said
so at the time.

Clinton stated that nuclear power research "wasn't needed" in his first
State of the Union address in 1993:

http://www.presidency.ucsb.edu/ws/index.php?pid=47232

"We are eliminating programs that are no longer needed, such as
nuclear power research and development. We're slashing subsidies
and canceling wasteful projects."

--President William J. Clinton, February 17, 1993

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

Andrew,

The potential of the IFR was made VERY CLEAR to government officials by my former collegues at Argonne.

It wasn't the uranium mining industry.

Gregory,

My comment was intended to be facetious - just pointing out that it would put uranium mining out of business. It was ultimately Congress that voted to end funding.

It appears that a NAS report in 1994 opposed development of plutonium fueled reactors, including the IFR, on security grounds. So Clinton was not without some support. I haven't been able to find that report. But it seems to me that the fuel cycle from thermal reactors with its high level (including plutonium) waste is as much of a security threat.

AM

 

[Morbius]

It appears that a NAS report in 1994 opposed development of plutonium fueled reactors, including the IFR, on security grounds.

Andrew,

The IFR addresses those concerns. In the IFR; plutonium NEVER LEAVES the
high radiation area around the reactor. The IFR features on site reprocessing of
spent fuel. That's why the IFR uses metal, rather than ceramic fuel.

When spent fuel is removed from the IFR, it is reprocessed by "halide slagging" and
electrorefining. Any plutonium that remains in the spent fuel is sent back to the
reactor as Dr. Till stated in his interview. Only short-lived fission products leave the
IFR as waste.

I find it difficult to believe that the NAS included the IFR in a report citing the
security problem. I'm sure the NAS did, or SHOULD have; understood that
there is no security problem with plutonium in IFR waste. The plutonium produced
by the IFR is immediately recycled back to the IFR as fuel.

Additionally, as Dr. Till stated; the IFR reprocessing scheme doesn't separate out
the plutonium by itself. It leaves other actinides and other plutonium isotopes mixed
in with the Pu-239. As Dr. Till stated; it is impossible to use IFR waste plutonium
as nuclear weapons fuel.

As Dr. George Stanford pointed out, the authors of the NAS study evidently didn't
understand the proliferation resistance of the IFR:

http://www.nationalcenter.org/NPA378.html

which also details the conclusions by nuclear weapons designers at
Lawrence Livermore National Laboratory:

"Some people do say that, but they're wrong, according to expert bomb designers
at Livermore National Laboratory. They looked at the problem in detail, and concluded
that plutonium-bearing material taken from anywhere in the IFR cycle was so ornery,
because of inherent heat, radioactivity and spontaneous neutrons, that making a bomb
with it without chemical separation of the plutonium would be essentially impossible -
far, far harder than using today's reactor-grade plutonium."

Real nuclear weapons experts from Lawrence Livermore shot down the contentions
of the authors of the NAS report [ who aren't nuclear weapons experts ]. IFR fuel
cycle plutonium can't be used as bomb fuel.

So what is the security concern?

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

A
Real nuclear weapons experts from Lawrence Livermore shot down the contentions of the authors of the NAS report [ who aren't nuclear weapons experts ]. IFR fuel cycle plutonium can't be used as bomb fuel.

So what is the security concern?

I agree that the IFR does not appear to produce material that could be easily used to produce a nuclear bomb. Not so with conventional reactors.

AM

 

[Morbius]

I agree that the IFR does not appear to produce material that could be easily used to produce a nuclear bomb. Not so with conventional reactors.

Andrew,

Even then.

The DOE has acknowledged that one can use so-called "reactor grade" plutonium,
that is plutonium from the nuclear waste of a commercial power reactor; in the
making of a nuclear weapon. However, it is difficult to do so; and may be beyond
the capability of a nascent nuclear proliferant.

What a nuclear weapons designer wants is plutonium that is made in special
"production reactors" in which the irradiated fuel is discharged after a relatively
low burn-up. That's how one gets nuclear bomb fuel.

A commercial power reactor is a relatively inefficient and expensive way to get
nuclear weapons material.

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

What a nuclear weapons designer wants is plutonium that is made in special "production reactors" in which the irradiated fuel is discharged after a relatively low burn-up. That's how one gets nuclear bomb fuel.

A commercial power reactor is a relatively inefficient and expensive way to get nuclear weapons material.

The frightening result, however, is that with a bit of depleted U and a breeder reactor, a rogue nation could easily make a bomb. The controls on depleted U are not nearly as strict as U235 or Plutonium. Depleted U is ubiquitous.

AM

 

[Morbius]

The frightening result, however, is that with a bit of depleted U and a breeder reactor, a rogue nation could easily make a bomb. The controls on depleted U are not nearly as strict as U235 or Plutonium. Depleted U is ubiquitous.

Andrew,

WRONG!

You can't get depleted Uranium; i.e U-238 to go critical in even a breeder reactor!

You need fissile material; U-235 and/or Pu-239 to fuel a reactor to turn U-238 into
bomb material.

If all you have is U-238 [ depleted Uranium ]; and no fissile material [ U-235 / Pu-239 ]
then you can't make a bomb or weapons material.

That's why the controls are on U-235 and Pu-239 and not depleted Uranium [ U-238 ].

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

Andrew,

WRONG!

You can't get depleted Uranium; i.e U-238 to go critical in even a breeder reactor!

You need fissile material; U-235 and/or Pu-239 to fuel a reactor to turn U-238 into
bomb material.

If all you have is U-238 [ depleted Uranium ]; and no fissile material [ U-235 / Pu-239 ]
then you can't make a bomb or weapons material.

That's why the controls are on U-235 and Pu-239 and not depleted Uranium [ U-238 ].

I was not suggesting the U-238 is fissile. But with a neutron source (eg. P-239) (and a reactor) you can turn fertile U-238 into fissile P-239. You could then use the resulting P-239 to turn more U-238 into more P-239 etc. With just a little P-239 and a lot of U-238 you could produce a lot of fissile material. We don't seem to be controlling the depleted U.

AM

 

[theCandyman]

I think that would take a long while. Even with enriched Uranium, if I remember correctly, it took several months to make enough Plutonium for the first Pu-239 based atomic bomb.

Also, is a CANDU reactor not considered critical? Or it's fuel not considered depleted Uranium (i.e. natural Uranium is not depleted)?

 

[Astronuc]

I think that would take a long while. Even with enriched Uranium, if I remember correctly, it took several months to make enough Plutonium for the first Pu-239 based atomic bomb.

Also, is a CANDU reactor not considered critical? Or it's fuel not considered depleted Uranium (i.e. natural Uranium is not depleted)?

CANDUs are critical at constant power, and the power level can vary. CANDUs use 'natural' U (~0.7% U-235), although lately the U is slightly enriched in order to reduce the number of discharged fuel assemblies.

U-238 is fertile. A neutron source (e.g. Po-Be, Pu-Be) has a very low neutron density, so with just a neutron source, it would take a long time to convert kgs of U-238 to Pu-239.

A friend and colleague of mine used to make logs of U-238 (DU) for Pu-239 production. It was a matter of simply inserting U-238 into a production reactor for many months, then removing the material and sending it to a reprocessing/recovery facility.

Reactor grade Pu contains amounts of Pu-241 and Pu-242, in addition to fission products (FP), so it would require remote handling to separate the Pu-239 and Pu-240 from the radioactive FP and one would still have Pu-241,242 to deal with.

 

[Morbius]

I was not suggesting the U-238 is fissile. But with a neutron source (eg. P-239) (and a reactor) you can turn fertile U-238 into fissile P-239. You could then use the resulting P-239 to turn more U-238 into more P-239 etc. With just a little P-239 and a lot of U-238 you could produce a lot of fissile material. We don't seem to be controlling the depleted U.

Andrew,

WRONG again - I'm sorry!

First Pu-239 is not what we call a "neutron source" - it is a fissile isotope; but has a
very low rate of spontaneous fissions - about 10 fissions/sec per kilogram.

You are in ERROR in saying that "with just a little Pu-239 and a lot of U-238..."; that
you could bootstrap your way into having a lot of fissile material. Unless you have
a "critical mass" of Pu-239 [ NOT "just a litttle" ] - you can't do ANYTHING!

That's why there are the controls on the amount of Pu-239. You aren't allowed to
have a "critical mass" of Pu-239.

The reason we don't control the depleted uranium U-238 is because we DON'T NEED to!

Besides - if someone wants Uranium; they could dig up natural uranium; at least
that has some more U-235 in it!

Depleted Uranium is even MORE USELESS than natural uranium from the ground
when it comes to making nuclear weapons.

Attempting to control depleted uranium would be counterproductive. It would sap
resources in trying to control the vast amount of a material that has industrial
uses from commercial airliner ballast to pigments and glazes. All for a
ZERO payback in terms of increased safety and security.

Dr. Gregory Greenman
Physicist

 

[Morbius]

I think that would take a long while. Even with enriched Uranium, if I remember correctly, it took several months to make enough Plutonium for the first Pu-239 based atomic bomb.

Candyman,

You are correct. The production reactors at Hanford started operation in September of
1944. As of July 1945, they had produced enough plutonium for 3 bombs - the bomb
tested in the "Trinity" test on August 15, 1945 at Alamagordo; the "Fat Man" bomb
that destroyed Nagasaki; and finally another "Fat Man" that was slated to be used if
Japan didn't surrender after Nagasaki. This bomb was ultimately detonated in the
"Crossroads Able" test at Bikini Atoll on July 1, 1946.

The Hanford production reactors were HUGE! The production of 3 critical masses
of plutonium in 9 months required a MASSIVE production complex. This is not a
"backyard operation" by any means. More moderate sized facilities requires YEARS
to make a critical mass.

There were 3 production reactors built at Hanford during the Manhattan Project;
B-Reactor, D-Reactor and F-Reactor. Here's a history of the B-Reactor:

http://www.hanford.gov/doe/history/files/HistoryofBArea.pdf

Also, is a CANDU reactor not considered critical? Or it's fuel not considered depleted Uranium (i.e. natural Uranium is not depleted)?

CANDU reactors are critical. The fuel in a CANDU is natural uranium which is
0.7% U-235. The other 99.3% of the Uranium is U-238.

The CANDU is moderated by heavy water. Heavy water is one of only two materials,
the other being graphite; that can moderate a reactor fueled by natural uranium.

The Hanford production reactors were moderated by graphite. The Savannah River
production reactors were moderated by heavy water.

All commercial power reactors in the USA are light water [ ordinary water ] moderated
and cooled. You can't get an LWR [ light water reactor ] to go critical on unenriched
or natural uranium. The fuel for an LWR must be enriched to about 3-4% U-235.

When you remove U-235 from natural uranium; what you have left is depleted uranium.

Think of natural uranium as milk. The U-235 is the cream or butterfat. Depleted
uranium is the buttermilk that's left after you make butter.

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

Andrew,

WRONG again - I'm sorry!

First Pu-239 is not what we call a "neutron source" - it is a fissile isotope; but has a very low rate of spontaneous fissions - about 10 fissions/sec per kilogram.

Ok. How about a little Californium then?

You are in ERROR in saying that "with just a little Pu-239 and a lot of U-238..."; that you could bootstrap your way into having a lot of fissile material. Unless you have a "critical mass" of Pu-239 [ NOT "just a litttle" ] - you can't do ANYTHING!

That's why there are the controls on the amount of Pu-239. You aren't allowed to have a "critical mass" of Pu-239.

The reason we don't control the depleted uranium U-238 is because we DON'T NEED to!

Are you saying that in a fast breeder reactor, the Plutonium that is produced from U-238 feedstock can only be used as fuel in the reactor and cannot be reprocessed to become weapons grade Plutonium?


AM

 

[Morbius]

Ok. How about a little Californium then?

Andrew,

If you are going to make a bomb like "Fat Man"; then you need about 10 kg of Pu-239.

That amounts to about 41.8 moles of Pu-239; or 2.5e+25 atoms.

Do you know how long it will take a radioisotope driven source like Californium to
make a critical mass of Pu-239? About a TRILLION years!

Most Californium radioisotopes have half-lives of less than 20 minutes!

Forget trying to breed weapons usable amounts of Plutonium by radioisotope-driven
means. You need a reactor; and for that you need masses of fissile material that
are controlled access.

Are you saying that in a fast breeder reactor, the Plutonium that is produced from U-238 feedstock can only be used as fuel in the reactor and cannot be reprocessed to become weapons grade Plutonium?

If the fast breeder reactor is the IFR - YES!

The mix of isotopes and radionuclides from the IFR system
can NOT be made into nuclear weapons!

The IFR was designed so that it doesn't present a proliferation risk!

In the interview Dr. Till said it was impossible to make nuclear weapons
with the IFR system, and he is right - it is IMPOSSIBLE by design.

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

Andrew,

If you are going to make a bomb like "Fat Man"; then you need about 10 kg of Pu-239.

That amounts to about 41.8 moles of Pu-239; or 2.5e+25 atoms.

Do you know how long it will take a radioisotope driven source like Californium to
make a critical mass of Pu-239? About a TRILLION years!

I am not suggesting that you don't need a reactor! You obviously need a large neutron flux so you need a sustained fission reaction.

All I was suggesting is that if there is no control on depleted uranium, a rogue nation could produce large quantities of weapons grade plutonium with a small amount of fissile material and a (non IFR) breeder reactor and a reprocessing facility. Obviously if you have more fissile material, you can get production up more quickly.

AM

 

[Morbius]

I am not suggesting that you don't need a reactor! You obviously need a large neutron flux so you need a sustained fission reaction.

All I was suggesting is that if there is no control on depleted uranium, a rogue nation could produce large quantities of weapons grade plutonium with a small amount of fissile material and a (non IFR) breeder reactor and a reprocessing facility. Obviously if you have more fissile material, you can get production up more quickly.

Andrew,

You still don't understand; you need a "critical mass" of the fissile material.

If the rogue nation has a "small amount" of fissile material; less than the
critical mass; it does ABSOLUTELY NO GOOD!

if you don't have enough fissile material, you don't have a critical mass;
so the reactor doesn't work - and you can't convert U-238 into Pu-239.

Do you understand the concept of "critical mass"? Reactors just flat out
don't work, until you have a minimum amount of the material. If you have
a "small amount"; it doesn't mean the reactor works at a low level; it
means the reactor doesn't work AT ALL! You need a certain minimum
amount, called the "critical mass" before the reactor will work at all.

So you control the fissile material; like U-235 and Pu-239.

If your controls on U-235 and Pu-239 are successful; it DOESN'T MATTER
how much U-238 they get - they can't do anything with it.

It's EASIER to control the fissile U-235 and Pu-239 than depleted uranium.

If you control the amount of fissile material someone can possess; you can
let them have all the depleted uranium they want; because they can't convert
it to fissile material.

Additionally, natural uranium is "BETTER" than the depleted uranium - at
least it has some U-235 in it. It makes NO SENSE to control depleted uranium
and not control natural uranium.

The problem with trying to control natural uranium is that it is EVERYWHERE!

Natural uranium is one of the most evenly distributed materials in the Earth's crust.

Pick the area of a football field ANYWHERE and excavate it for a depth of about
6 feet; and you will get about a kilogram of natural uranium out of that volume.

You CAN'T control natural uranium - it's LITERALLY EVERYWHERE!

Since you can't control natural uranium; it a WASTE of EFFORT to control
depleted uranium.

Your only hope is to control the fissile material - THAT you do have a hope of
controllng. Without the fissile material; you can't convert fertile depleted uranium
or fertile natural uranium into bomb fuel.

That's why it's WASTED EFFORT to control depleted uranium!

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

I understand that a critical mass of fissile material is required to initiate nuclear chain reaction but I didn't think it is that much material for Pu-239 - a few kg. or about half a litre in size.

So is it not correct that this small amount of Pu-239 with a lot of U-238 (and a breeder reactor) one could continue to run the reactor and continue indefinitely to produce weapons useable plutonium? If not, then I guess I am missing something important (or critical!). My point is that without the U-238 one would have to mine it or purchase (or steal) it. Sale of natural or uranium is very restricted but it does not appear that sale of depleted U is regulated.

I certainly appreciate your posts and your patience.

AM

 

[Astronuc]

Fast reactor fuel is usually 20% Pu, but LWR reactors are on the order of 5-8% Pu - with the Pu being 239, 240, 241 and perhaps some 242.

Of course, one could use a CANDU type reactor, which requires a substantial inventory of heavy water.

So one needs a good sized reactor to convert fertile into fissile material, and then one needs a reprocessing program. Reactors require special materials, particularly materials for control systems, and that would set off alarms in various intelligence organizations.

The IAEA would likely find out about it, given the large scale industrial process.

Large quantities of DU are really only available from enrichment facilities, and I would imagine it would attract someone's attention if large quantities of DU were being purchased.

Here is a useful discussion of Pu and its production.
http://www.uic.com.au/nip18.htm

 

[Morbius]

I understand that a critical mass of fissile material is required to initiate nuclear chain reaction but I didn't think it is that much material for Pu-239 - a few kg. or about half a litre in size.

Andrew,

At normal density, it's more than just a few kilograms.

So is it not correct that this small amount of Pu-239 with a lot of U-238 (and a breeder reactor) one could continue to run the reactor and continue indefinitely to produce weapons useable plutonium? If not, then I guess I am missing something important (or critical!). My point is that without the U-238 one would have to mine it or purchase (or steal) it. Sale of natural or uranium is very restricted but it does not appear that sale of depleted U is regulated.

I certainly appreciate your posts and your patience.

Here's an analogy that may illustrate my point.

Suppose we want to control the production of illegal drugs; heroin and pot, which come
from opium poppies and pot plants. How do we do that?

The farmer that grows the plants needs a few things; the seeds, soil, water and sunshine.

My suggestion for control is that anywhere you see someone growing these plants; you
confiscate the plants and don't let anyone have the seeds to plant. Without the seeds,
they can't grow the plants.

What you are saying, in essence; is let's put access controls on soil, water and sunshine.
Without soil, water and sunshine - you can't grow pot and opium poppies. That's true -
but - access controls on soil, water, and sunshine? GOOD LUCK doing THAT!

If you are concerned about what someone can do with depleted uranium; then you have
to be EQUALLY if not MORE concerned about natural uranium. Depleted uranium is
natural uranium with the fissile U-235 removed.

Or to turn that around; you could reconstitute natural uranium by taking depleted uranium
and adding the fissile U-235 back in. That fissile U-235 is only going to HELP you
breed plutonium by increasing the amount of neutrons due to U-235 fission.

So natural uranium is BETTER than depleted uranium as a fertile material for breeding
plutonium. If you control access to depleted uranium, you're kidding yourself, because
the proliferator is just going to use natural uranium in its stead.

So you would need to control natural uranium too. However, natural uranium is literally
EVERYWHERE - like soil, water and sunshine.

So to return to my analogy above; your point above that it takes just a small amount
of Pu-239 or U-235; is analogous to the point that it takes just a few seeds from
opium poppies or pot plant to start a drug farm.

So you would rather put access controls on soil, water, and sunshine.

I'm saying THAT'S more difficult than controlling a few seeds.

It's pointless trying to control soil, water and sunshine. It's pointless trying to
control natural uranium. Natural uranium is a ready substitute for the depleted
uranium you want to control. That's why trying to control depleted uranium is
pointless.

You control the access to the fissile materials, U-235, or Pu-239; because
those are the only things that you can realistically get a handle on controlling.

Make sense now?

Dr. Gregory Greenman
Physicist

 

[Andrew Mason]

What you are saying, in essence; is let's put access controls on soil, water and sunshine. Without soil, water and sunshine - you can't grow pot and opium poppies. That's true - but - access controls on soil, water, and sunshine? GOOD LUCK doing THAT!

If gathering raw uranium from the Earth was as easy as finding sunshine and soil, I would agree with you.

But it isn't. If you don't have a mineable deposit you face enormous costs to produce a small amount of U. You would need a mining facility (or you need the technology to get it out of sea-water - which is not yet widely available) and very large processing operation, not to mention refining facilities and the expertise to run them.

If you have a mineable deposit, the cost is more manageable but still requires a significant investment in processing and is hard to hide.

Since U-238 is the "seed" for Pu production in breeder reactor, I think the rogue nation will be looking for an easy supply of DU.

AM

 

[Morbius]

If gathering raw uranium from the Earth was as easy as finding sunshine and soil, I would agree with you.

But it isn't. If you don't have a mineable deposit you face enormous costs to produce a small amount of U.

Andrew,

As I showed in a previous post; you really don't need to have mineable deposits.

You can chemically separate out uranium from just about ANYWHERE.

Chemical separation is not that difficult.

You would need a mining facility (or you need the technology to get it out of sea-water - which is not yet widely available) and very large processing operation, not to mention refining facilities and the expertise to run them.

If you have a mineable deposit, the cost is more manageable but still requires a significant investment in processing and is hard to hide.

The production facilities for fissile materials are the things that are difficult to hide.

The chemical processing facilities needed to extract uranium from ore are EASY to
disguise. The processing operation isn't large at all, and doesn't have a big footprint.

[For example, Iraq hid their uranium mining operation from IAEA inspectors for the
entire DECADE of the 1980s. It wasn't until UNSCOM / UNMOVIC got in there
after the Gulf War of 1991 that the extent of the Iraq nuclear program became apparent.]

Uranium mining and extraction doesn't look much different than practically any other
mineral recovery effort. There's nothing that shouts out "Uranium".

You've got it backwards. You think the fissile material production is easy to hide,
while uranium ore extraction is not. It's actually the OTHER way around!

Since U-238 is the "seed" for Pu production in breeder reactor, I think the rogue nation will be looking for an easy supply of DU.

The U-238 isn't the "seed". The U-238 is like the soil and water.

An opium poppy converts minerals from the soil into the opium desired by the
drug trade; based on the "blueprint" contained in the seed. The soil is the raw material
for the plant; not the seed. The U-238 is the raw material, not the blueprint.

This has been thoroughly studied. Scientists, engineers, nuclear inspectors have
researched the control of nuclear materials for years.

Now you are trying to say that everyone is "missing something" because they haven't
put depleted uranium under "lock and key".

If what you propose would do any good; we'd already be doing it.

Dr. Gregory Greenman
Physicist