We are overloading the planet: Now What?

[Bomb#20]

90 * (1/5%) * 7 = 12600

???

It's from your link. 90 years is how long he says proven uranium reserves would last at the current rate of use. 5% is how much of our remaining fossil fuels he says that's equivalent to. 7 is how many times more energy supply than our remaining fossil fuels he says using breeder reactors would turn the proven reserves of uranium into. So I did the arithmetic.

An expert would know native "too dilute" natural uranium works just fine in a nuclear reactor. If he told the Canadians it must be enriched to become viable they'd roll their eyes and go right on powering their cities with the same natural uranium reactors they've been using for decades. What "must be" done to get a reactor to work depends on the reactor; not everybody builds their reactors to American designs.

Stupid Yankees! The US Nuclear Regulatory Commission says uranium needs to be enriched before it can be used ( see Uranium Enrichment).

Oh my god, the US government is US-focused! Oh my god, Americans aren't paying much attention to the rest of the world! I'm shocked, shocked!

Maybe we should all write to them and tell them they are full of baloney. Can you give us a credible source that refutes their claim?

You didn't google "Canadian nuclear reactors"?

Nuclear power in Canada - Wikipedia

en.wikipedia.org

"All currently operating Canadian nuclear reactors are a type of pressurized heavy-water reactor (PHWR) of domestic design, the CANDU reactor. CANDU reactors have been exported to India, Pakistan, Argentina, South Korea, Romania, and China. While there are (as of 2022) no plans for new CANDUs in Canada or elsewhere, Canada remains a technology leader in heavy water reactors and natural uranium fueled reactors more broadly. ...
Building partly on the experimental data obtained from ZEEP, the National Research Experimental (NRX)—a natural uranium, heavy water moderated research reactor—started up on July 22, 1947. ...
The 20 MWe NPD started operation in June 1962 and demonstrated the unique concepts of on-power refuelling using natural uranium fuel, and heavy water moderator and coolant. These features formed the basis of a fleet of CANDU power reactors ..."​

(I'd also point out that the fact that unenriched uranium can be used should be painfully obvious even to infamously provincial Americans, since the Manhattan Project built its first reactor in 1942.

Chicago Pile-1 - Wikipedia

en.wikipedia.org

"The reactor used natural uranium."​

Obviously so, since in 1942 enriched uranium existed only in milligrams. But of course that was a research reactor, not a power-generation reactor.)

We know how to build breeder reactors.

Yes, that is one way to get around potential shortages of uranium. It is very risky, because the plutonium produced can easily be made into nuclear bombs, but yes that is an option.

For sufficiently difficult values of "easily". Yes, diversion is a concern, but some breeder designs are more resistant to it than others. Here's one that's been proposed:

Traveling wave reactor - Wikipedia

en.wikipedia.org

 

[bilby]

Predictions of peak oil have been put off by improved survey and drilling methods the fact that they were nonsense to begin with, based as they were in a failure to grasp the vital difference between a reserve and a resource, but it is still finite.

FTFY.

Obviously oil and coal are finite; Equally obviously it dorsn't matter, because if we burn most of the total resource we will be completely fucked well before the stuff has all been used up.

 

[Loren Pechtel]

Would it be economical to use that dispersed uranium to make electricity for the masses?

The richest people might be able to afford such energy. Could you and I afford it?

The 700 year figure was for uranium that was already known to be concentrated enough for profitable extraction; it wasn't for dispersed uranium.

"Proven uranium reserves would last 90 years at the current rate of use" (https://tmurphy.physics.ucsd.edu/energy-text/energy-murphy.html p258) We don't know how much more we will find that is economical to process, but we have been looking hard, and not finding much.

But people here are talking about using it for most of our electric power generation, or even most of our total power generation. Then that supply would go much quicker.

I followed your link's links.

"First, we take 0.72% of the 7.6 million tons available to represent the portion of uranium in the form of U235. ...​

We see from this that proven uranium reserves give us only ... about 5% of our total remaining fossil fuel supply. ...​

Proven uranium reserves would last 90 years at the current rate of use...​

To be fair, proven reserves are always a conservative lower limit on estimated total resource availability. And since fuel cost is not the limiting factor for nuclear plants, higher uranium prices can make more available, from more difficult deposits. ...​

In its native form, U235 is too dilute in natural uranium—overwhelmingly dominated by U238—to even work in a nuclear reactor. It must be enriched to 3–5% concentration to become viable. ...​

But what if we could use the bulk uranium, U238, in reactors and not only save ourselves the hassle of enrichment, but also gain access to140 times more material, in effect? Doing so would turn the proven reserves of uranium into about 7 times more energy supply than all of our remaining fossil fuels."​

There are three takeaways from all this. First, the guy is not an expert on nuclear power; he's just regurgitating conventional American practice. An expert would know native "too dilute" natural uranium works just fine in a nuclear reactor. If he told the Canadians it must be enriched to become viable they'd roll their eyes and go right on powering their cities with the same natural uranium reactors they've been using for decades. What "must be" done to get a reactor to work depends on the reactor; not everybody builds their reactors to American designs.

Second, see everything bilby keeps having to write over and over about the difference between proven reserves and how much we have.

And third, the guy just said our proven reserves are enough for twelve thousand six hundred years ( 90 * (1/5%) * 7 = 12600 ), and he granted that that's a conservative lower limit, even if we don't take price rises into account. We know how to build breeder reactors.

What reactor can eat plain U238? I thought you couldn't sustain a chain reaction in it. (Now, using it in a breeder does work.)

 

[Loren Pechtel]

Again, the claim here is that we are so overwhelmingly certain that modifying our regulations will allow nuclear reactors to save the planet, that we are not allowed to ask, "What happens if nuclear doesn't save the planet?"

We are where we started--with no solution in sight. The "green" answer of destroying our economy for no real benefit isn't an answer.

Please show me the evidence that, when nuclear reactors are operating without unneeded regulations, the result will be so overwhelming that we should not even ask what we should do if nuclear fails to fulfill this promise.

Simple: Deaths per TwH:
Nuclear: 0.03
Gas: 2.82
Oil: 18.43

In a regulatory climate that was optimum for the consumer these numbers should be approximately the same rather than nearly three orders of magnitude apart. And reality is worse than that because the oil and gas numbers do not count the threat from global warming. (Yes, there are other power sources with numbers similar to nuclear--but none are remotely capable of meeting the demand.)

(Note that you might find a 0.07 number floating around for nuclear. That's based on assigning the deaths from the Fukushima evacuation to nuclear rather than to politics. The expected death toll of staying put was less than one.)

Regarding the claim of grass-roots resistance being the problem, see .

The economic problem is a regulatory problem. Reactors weren't unduly expensive until they were basically regulated out of existence by requiring them to be as safe as feasible.

 

[Loren Pechtel]

We know how to build breeder reactors.

Yes, that is one way to get around potential shortages of uranium. It is very risky, because the plutonium produced can easily be made into nuclear bombs, but yes that is an option.

A common misperception. The reality is that reactor grade plutonium is extremely hard to make into a bomb.

The basic problem is one of neutrons. It all comes down to the multiplication factor. What happens when a neutron enters your mass of material? Fundamentally, neutrons can escape (which is why critical mass matters--too much surface to volume and you lose too many neutrons), they can dissipate in non-fissile reactions (27% in pure Pu-239) or they can cause fission (average 2.98 neutrons per fission.) All the fancy engineering of a nuclear weapon is to very quickly convert the material from a form where the multiplication factor is less than one to a form where it is in excess of two.

U-235 doesn't emit very many neutrons, you can simply slam two pieces together (Little Boy) with a good chance that you get full assembly before some neutron starts the reaction. (Note: The Little Boy design actually had about a 1% chance of being a fizzle but at the time they knew it could happen but didn't have the computer power to estimate the odds.)

Pu-239 is far more sensitive. Try the simple approach and the expected result is the reaction starts while the pieces aren't quite together yet. The multiplication factor is low, the heat produced drives the material apart before any large amount of energy has been released. (Over the decades there have been a few cases where someone accidentally put too much plutonium in a container--a blue flash, a bang too weak to kill, but anyone nearby is a walking corpse. The only way I see to use it as a weapon is to thwart Indiana Jones as it could be used to make a booby trap that would still work reliably after many centuries.)

Pu requires carefully engineered explosive lenses to crush a sphere far faster than could be done with a gun type device. Even this has it's limits, though--if the neutron flux is too high you're not going to be able to assemble it fast enough at least with chemical explosives. (This got me to wondering if it could be used in the second stage of a Teller Ulam device....) The problem here is one of economics:

For a bomb the desired reaction is U-238 + n -> U-239, decays to Np-239, decays to Pu-239.
For a bomb the undesired reaction is Pu-239 + n -> Pu-240.
For a reactor this reaction is not of concern as they don't care about neutron emitters.

Thus to make a bomb you leave the fuel in the reactor only for a short period of time, before much of the decay has occurred. This is not of importance to a power reactor, there's no reason to change the fuel nearly as often. Thus the plutonium from a reactor will have a high concentration of Pu-240. Plutonium recovered from reprocessing is virtually useless in a bomb.

And what about separating them? If you're going to go to the effort of separating might as well go for a U-235 bomb. While it's not my field I can see no way it isn't at least 3x as hard to separate Pu-239 from Pu-240 as it is to separate U-235 from U-238. To separate them you convert them to a gas (and AFIAK the lightest gas you can make out of them is by adding 6 fluorine atoms) and do something to separate it by density. The plutonium atoms are 3x closer in weight.

 

[Bomb#20]

What reactor can eat plain U238? I thought you couldn't sustain a chain reaction in it. (Now, using it in a breeder does work.)

We weren't talking about plain U238; we were talking about unenriched natural uranium. 140 parts U238, one part U235. CANDU reactors can eat it. (As can a few obscure types.) The power still comes from the U235; the U238 mostly still turns into waste. CANDU is just a design in which having 140 parts of U238 in the way doesn't ruin the U235 chain reaction.

What's going on is the neutrons from a U235 fission come out too fast and need to be slowed down. The usual way is to make them bounce around in water before they hit another U235. But the problem is that when you run them through water some of the neutrons hit hydrogen nuclei and fuse with them and form deuterium, instead of bouncing off and slowing down. The loss of neutrons is why it's hard to sustain a chain reaction. So what do you do about it? There are three simple solutions:

1 - Enrich the uranium. Fewer neutrons times more U235 targets gives enough collisions to keep the chain reaction going. This is the usual approach.
2 - Stop the water from absorbing neutrons. A hydrogen nucleus can't turn into deuterium twice, so use water in which most of the hydrogen nuclei already absorbed neutrons and turned into deuterium, aka "heavy water". CANDU reactors do this.
3 - Don't use water. Find something else that's good at slowing neutrons. The early atomic piles used graphite.

 

[bilby]

What reactor can eat plain U238? I thought you couldn't sustain a chain reaction in it. (Now, using it in a breeder does work.)

We weren't talking about plain U238; we were talking about unenriched natural uranium. 140 parts U238, one part U235. CANDU reactors can eat it. (As can a few obscure types.) The power still comes from the U235; the U238 mostly still turns into waste. CANDU is just a design in which having 140 parts of U238 in the way doesn't ruin the U235 chain reaction.

What's going on is the neutrons from a U235 fission come out too fast and need to be slowed down. The usual way is to make them bounce around in water before they hit another U235. But the problem is that when you run them through water some of the neutrons hit hydrogen nuclei and fuse with them and form deuterium, instead of bouncing off and slowing down. The loss of neutrons is why it's hard to sustain a chain reaction. So what do you do about it? There are three simple solutions:

1 - Enrich the uranium. Fewer neutrons times more U235 targets gives enough collisions to keep the chain reaction going. This is the usual approach.
2 - Stop the water from absorbing neutrons. A hydrogen nucleus can't turn into deuterium twice, so use water in which most of the hydrogen nuclei already absorbed neutrons and turned into deuterium, aka "heavy water". CANDU reactors do this.
3 - Don't use water. Find something else that's good at slowing neutrons. The early atomic piles used graphite.

Discussion of moderation in-thread is against the Terms of Use of the board.



There's also:

4 - Encourage lots of the fast neutrons to hit the ²³⁸U that's hanging around (or give it some other targets, such as ²³²Th), to create ²³⁹Pu (or ²³³U), which are further fuel for fission.

A fast breeder reactor can actually use negative quantities of fuel - That is, you get out more fissile material (which can be reprocessed into MOX fuel for existing PWRs) than you put in. This makes it very difficult to run out of fuel for nuclear power, particularly given the vast amounts of Thorium in the lithosphere.

Some of the Gen IV fast spectrum molten salt reactors currently in the design phase can even use High Level "Waste" from PWRs as a feedstock. The spent fuel doesn't need chemical processing at all; You can just chop it up and dissolve it directly into the molten salt.

Liquid fueled reactors have a lot of advantages over solid fuel designs, but US reactor design has to date been dominated by naval reactor requirements, and IMO insufficient work has been done on designs more suitable for commercial use.

This is in part driven by the availability of reactor operator skills amongst former naval personnel, who are the backbone of the US commercial reactor operator community.

 

[Merle]

Supply of Uranium - World Nuclear Association

Uranium is a relatively common metal, found in rocks and seawater. Economic concentrations of it are not uncommon.

world-nuclear.org

That is the source I have been using to show that, yes, we are finding more uranium, but we are doing it by spending a whole lot more money to find it.



The graph doesn't say the dollars are inflation adjusted, so that would make a difference. Nevertheless, it does show the skyrocketing search for more uranium starting around 2007. And it makes sense that exploration skyrocketed at that time. It was becoming obvious we needed other energy sources for the future, and nuclear was certainly a key player. Anybody in the business would certainly want a big supply of quality reserves on the books. Exploration skyrocketed. They found little of the cheap (<130/KgU) stuff but did find some more expensive stuff. Looking at this, it is hard to say that the reason we haven't found more is that we haven't tried.

Fuel is a minor portion of the cost of nuclear power, so we could certainly afford to search harder. Nevertheless, the chart to me indicates that there might not be a lot of readily-available, low-cost usable stuff out there.

Nobody is wasting money on prospecting and mineral assays in the search for stuff that's not going to run out for many decades.

See graph above.

 

[Merle]

Merle, Merle, Merle...

I said that my 80s era text said at the rate of the day there was about 700 years of uranium reserves.

Steve, Steve, Steve...

That's what I said you said.

My 80s era text put the global reserves at 700 years. Now it is less, obviously with increased demand.

Ah, so the original claim was that we had a known viable supply of uranium for 700 years at 1980s level of usage.

 

[Merle]

Predictions of peak oil have been put off by improved survey and drilling methods the fact that they were nonsense to begin with, based as they were in a failure to grasp the vital difference between a reserve and a resource, but it is still finite.

FTFY.

Obviously oil and coal are finite; Equally obviously it dorsn't matter, because if we burn most of the total resource we will be completely fucked well before the stuff has all been used up.

Informed peak oil writers are not saying that we will not find more oil. The claim has been that, for decades, we have been using oil far faster than we find it.

The most critical supply is the middle distillates used for diesel, jet fuel, and marine bunker fuel. It appears to have already reached its peak. See Our Oil Predicament.

We have delayed the peak due to massive fracking efforts to get the hard-to-access tight oil supplies. And this stopgap measure may have reached its limit. See The Peak Cheap Oil Debate

This time, the sky is really falling.

 

[Merle]

It's from your link. 90 years is how long he says proven uranium reserves would last at the current rate of use. 5% is how much of our remaining fossil fuels he says that's equivalent to. 7 is how many times more energy supply than our remaining fossil fuels he says using breeder reactors would turn the proven reserves of uranium into. So I did the arithmetic.

Ah, you were talking about breeder reactors. Yes, if we willing to accept the risks involved with breeder reactors, we can make our uranium supplies last much longer.

You didn't google "Canadian nuclear reactors"?

Nuclear power in Canada - Wikipedia

en.wikipedia.org

"All currently operating Canadian nuclear reactors are a type of pressurized heavy-water reactor (PHWR) of domestic design, the CANDU reactor. CANDU reactors have been exported to India, Pakistan, Argentina, South Korea, Romania, and China. While there are (as of 2022) no plans for new CANDUs in Canada or elsewhere, Canada remains a technology leader in heavy water reactors and natural uranium fueled reactors more broadly. ...​

Building partly on the experimental data obtained from ZEEP, the National Research Experimental (NRX)—a natural uranium, heavy water moderated research reactor—started up on July 22, 1947. ...​

The 20 MWe NPD started operation in June 1962 and demonstrated the unique concepts of on-power refuelling using natural uranium fuel, and heavy water moderator and coolant. These features formed the basis of a fleet of CANDU power reactors ..."​

Sorry, I missed that link. This is very interesting.

 

[Merle]

Again, the claim here is that we are so overwhelmingly certain that modifying our regulations will allow nuclear reactors to save the planet, that we are not allowed to ask, "What happens if nuclear doesn't save the planet?"

We are where we started--with no solution in sight. The "green" answer of destroying our economy for no real benefit isn't an answer.

Again, the question is what we should do if we find that technical solutions are unable to allow humans to continue at anywhere near their current consumption patterns in the next century. Some people here have refused to answer this question. They are so certain that technology can do it, the question doesn't even make sense. So they tell us they are justified in refusing to answer the question.

You, at least, acknowledge that the question can be addressed.

Your answer appears to be, that if technology fails, we are screwed, and there is no use even trying. Fair enough.

I still hold out the option that, if we really are in that condition, then options like reducing consumption per capita or a non-coercive movement to reduce birthrates can be put on the table. Hence, this thread to discuss our options.

You still have not explained how the green answer would destroy our economy. Sure, cutting back would hurt the economy. But how is that not better than stepping on the gas and driving at full speed headlong into the massive barrier ahead? If we hit the brakes before the crash, might not that improve our odds of survival?

Please show me the evidence that, when nuclear reactors are operating without unneeded regulations, the result will be so overwhelming that we should not even ask what we should do if nuclear fails to fulfill this promise.

Simple: Deaths per TwH:
Nuclear: 0.03
Gas: 2.82
Oil: 18.43

In a regulatory climate that was optimum for the consumer these numbers should be approximately the same rather than nearly three orders of magnitude apart. And reality is worse than that because the oil and gas numbers do not count the threat from global warming. (Yes, there are other power sources with numbers similar to nuclear--but none are remotely capable of meeting the demand.)

Oh my. By this logic, if the deaths per TwH of hooking generators up to stationary bicycles is say 0.03, then we could simply undo government regulations on stationary bicycles until the deaths on bicycles per TwH reach 2.82, and our energy problems will be solved?

I am glad the death per TwH for nuclear are low. And that may tell us we have some latitude to relax regulations. But that still does not answer the basic question: How does anybody know that relaxing these regulations will have such a huge effect that nuclear power will go on to supply virtually all the energy we would need in the next century?

 

[Millrat]

I am glad the death per TwH for nuclear are low. And that may tell us we have some latitude to relax regulations. But that still does not answer the basic question: How does anybody know that relaxing these regulations will have such a huge effect that nuclear power will go on to supply virtually all the energy we would need in the next century?

We don’t. What we do know is that the largest source of energy supplies consumed to date have enjoyed such relaxed regulations - virtually unregulated early on.

 

[steve_bank]

There is also natural background radiation. Radon gas is a problem is some areas. It can be a problem in homes.

Radon released from granite building materials can be released over the lifetime of use but typically will be diluted by ventilation. In addition to radon, naturally occurring radioactive elements in the granite can emit small amounts of beta and gamma radiation.

All granite, and most earthen materials, contain trace amounts of uranium and radium, emit gamma radiation and release radon gas.Nov 14, 2023

The is background natural X-ray radiation.

Jet crews and frequent flyers are exposed to higher radiation than at the surface.

How much radiation does air and space crew receive? <1 mSv in a year is on average received by aircrew where all routes flown do not exceed an altitude of about 9000 metres. 6 mSv in a year is a typical radiation doses received by aircrew flying long-haul polar routes.

Radiation Dose

Patient safety information about radiation dose from X-ray examinations and CT scans (CAT scans)

www.radiologyinfo.org

Naturally occurring "background" radiation

We are exposed to natural sources of radiation all the time. According to recent estimates, the average person in the U.S. receives an effective dose of about 3 mSv per year from natural radiation, which includes cosmic radiation from outer space. These natural "background doses" vary according to where you live.

People living at high altitudes such as Colorado or New Mexico receive about 1.5 mSv more per year than those living near sea level. A coast-to-coast round-trip airline flight is about 0.03 mSv due to exposure to cosmic rays. The largest source of background radiation comes from radon gas in our homes (about 2 mSv per year). Like other sources of background radiation, the amount of radon exposure varies widely depending on where you live.

To put it simply, the amount of radiation from one adult chest x-ray (0.1 mSv) is about the same as 10 days of natural background radiation that we are all exposed to as part of our daily living.

I would say deaths from nuclear power would be 'in the noise' compared to all the combined effects of background risks.

Natural gas stoves in a kitchen present long term health risks.

 

[Merle]

How does anybody know that relaxing these regulations will have such a huge effect that nuclear power will go on to supply virtually all the energy we would need in the next century?

We don’t.

I agree. We don't know that. But one person here insists that, if certain regulations and grassroots reactions were removed, we can be absolutely certain that nuclear power could meet most of our electrical needs this century.

I think he is wrong.

 

[Merle]

What we do know is that the largest source of energy supplies consumed to date have enjoyed such relaxed regulations - virtually unregulated early on.

What we also know is that once raw sewage flowed in rivers. And there are two problems with raw sewage in rivers: number one and number two.

Sometimes regulations are good.

 

[bilby]

Supply of Uranium - World Nuclear Association

Uranium is a relatively common metal, found in rocks and seawater. Economic concentrations of it are not uncommon.

world-nuclear.org

That is the source I have been using to show that, yes, we are finding more uranium, but we are doing it by spending a whole lot more money to find it.

View attachment 45430

The graph doesn't say the dollars are inflation adjusted, so that would make a difference. Nevertheless, it does show the skyrocketing search for more uranium starting around 2007. And it makes sense that exploration skyrocketed at that time. It was becoming obvious we needed other energy sources for the future, and nuclear was certainly a key player. Anybody in the business would certainly want a big supply of quality reserves on the books. Exploration skyrocketed. They found little of the cheap (<130/KgU) stuff but did find some more expensive stuff. Looking at this, it is hard to say that the reason we haven't found more is that we haven't tried.

Fuel is a minor portion of the cost of nuclear power, so we could certainly afford to search harder. Nevertheless, the chart to me indicates that there might not be a lot of readily-available, low-cost usable stuff out there.

Nobody is wasting money on prospecting and mineral assays in the search for stuff that's not going to run out for many decades.

See graph above.

Australia alone has vast amounts of uranium that is not being exploited at all, and most of the uranium produced here is a byproduct of mining for other metals, at the Olympic Dam copper mine (Olympic Dam also produces gold).

The three most populous states, New South Wales, Queensland, and Victoria, all prohibit uranium mining, and QLD and VIC also prohibit exploration for uranium. This makes both mining and exploration far more expensive than it needs to be, and is a purely political decision.

There is certainly plenty of readiliy available uranium (and thorium) out there, at costs not more than the ceiling imposed by the cost of seawater extraction mentioned earlier in the thread.

Availability of fuel is not going to be a problem for nuclear power within any sane planning horizon; We likely have enough to last longer than the existence of our species.

 

[bilby]

Informed peak oil writers are

...an entirely fictional species.

 

[bilby]

if we willing to accept the risks involved with breeder reactors

There are no risks of breeder reactors that come anywhere close to the risks of any non-nuclear electricity generation technology, except onshore wind power; If we are NOT willing to accept that level of risk, then we are not willing to risk having electricity at all.

What specific risks do you have in mind?

 

[bilby]

the question is what we should do if we find that technical solutions are unable to allow humans to continue at anywhere near their current consumption patterns in the next century

We shall die in large numbers.

This is not in dispute, but it's also not going to happen.

You could as well say "the question is what we should do if we find that a huge asteroid will collide with the Earth in a few weeks time". IF that were the case, we could do nothing at all except die. But it isn't the case, so why are you worrying about it?

Technical solutions currently available to us ARE sufficient to "allow humans to continue at anywhere near their current consumption patterns in the next century", and for many centuries afterwards.

The question you should ask is, what we should do if we find that political and sociological barriers to implementing techology are unable to allow humans to continue at anywhere near their current consumption patterns in the next century.

And the answer is "We should elect saner politicians", which in turn implies that we should better educate our voting population, many of whom still falsely believe that our most dangerous electricity generation technologies are "safe enough", while also believing that our safest technology to do the same thing is "too risky" to even consider.

When decisions are made based on not just inaccurate but completely backwards risk assessments, continuing to do the wrong and stupid things is a certainty.