First! Fusion Net Energy Gain

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Zorba

Lifer
Oct 22, 1999
14,526
9,899
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And you complete trips by travelling the distance required, not by sitting in a vehicle. That's why distance is the correct measure, not hours. Again, even if we grant the assumption that the per-hour risk is equal if your measure of safety obscures the fact that driving across the country is ten times more dangerous than flying that is not a good measure.

Both miles and hours obsurces the most dangerous times of driving and flying, to/landing and city driving. Per trip/cycle actual captures this a bit better.

It's unclear to me why you think these relationships should be linear. That being said, we absolutely do regulate safety differently for small planes than for large ones for exactly that reason (among others) - fewer lives at risk.
You are the one proposing risk analysis via output versus exposure. Only very small planes are regulated differently, all transport aircraft are Part 25.
 

fskimospy

Elite Member
Mar 10, 2006
83,985
47,938
136
Both miles and hours obsurces the most dangerous times of driving and flying, to/landing and city driving. Per trip/cycle actual captures this a bit better.
I'm not at all confident that's the case and distance traveled is the primary method used by every transit agency I am aware of.

You are the one proposing risk analysis via output versus exposure. Only very small planes are regulated differently, all transport aircraft are Part 25.
I am showing you why that is relevant for planes, I did not say that planes and power plants should be regulated the same way.

Again, the point of the car/plane analogy was to point out that people are very bad at assessing risk - plane travel is MUCH safer than driving but people think otherwise. Same with nukes vs. fossil fuels - nukes are much safer but people think the opposite.
 

Maxima1

Diamond Member
Jan 15, 2013
3,515
756
146
I forgot to add. As I've mentioned before the reason Chernobyl wasn't worse is because the Soviet Union was willing to risk thousands of lives preventing further catastrophe. What country would do that today? Definitely not the US or Japan, maybe China.

The NRC is just as likely to be corrupted as the FAA, FCC, FTC, and SEC, and didn't exactly come out looking great after TMI. Plus to actually have the impact you are talking about when need nukes all over the world. Do you think Inida and Saudi Arabia will operate their plants at the same standard as the US and France?

Chernobyl is apples and oranges to even old reactor designs.


In its basic concept, the Chernobyl reactor resembles the world’s first reactor--an “atomic pile,” it was called then--of graphite and uranium built under a University of Chicago stadium in 1942, at the start of the Manhattan Project, the program that developed the first atomic bomb. It differs radically from most nuclear power plants in the West, which use water as both the moderator and coolant.

In most water-cooled reactors, the opposite effect occurs. A loss of cooling water means a loss of the moderator as well, and neutrons are no longer slowed enough to maintain fission. Instead of accelerating, the nuclear chain-reaction stops.

Even in conventional reactors, intense heat is still emitted from decaying radioactive wastes in the fuel. This is sufficient to damage the core severely, as happened in 1979 at the Three Mile Island nuclear plant near Harrisburg, Pa.

At Three Mile Island, however, there was no devastating explosion and no significant release of radioactivity. The damaged core remained inside its heavy, steel pressure vessel, and the steel-and-concrete building surrounding the reactor trapped the radioactivity that leaked from the cooling system.

At Chernobyl, the use of combustible graphite in the core and the absence of a containment structure account for the massive scale of radioactive contamination that was released into the environment, according to safety engineers familiar with the report.

 

Perknose

Forum Director & Omnipotent Overlord
Forum Director
Oct 9, 1999
46,038
8,725
136
At Three Mile Island, however, there was no devastating explosion and no significant release of radioactivity.
Although all the published research says otherwise, I remember a lab scientist, a very grounded person, telling me at the time that in the immediate aftermath radiometers downwind were spinning off the charts.
 
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sdifox

No Lifer
Sep 30, 2005
94,976
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It is.

Try it in space sometime.
gettyimages-114951190-b3daa7ad018e8b1ee0515920b03cb8d03dc8ad88.jpg

Nights are shorter but maintenance is a bitch.


What is the power envelope of ISS, assuming it is not classified.
 

Paratus

Lifer
Jun 4, 2004
16,672
13,418
146
Which was obviously my point. On a per hour basis driving and flying are roughly on par with each other, so the exposure difference is dominant in the equation. The example I gave of skiing versus walking in your own house is equivalent to your driving vs wing suit jumping.

Your original post didn't consider exposure at all and was much more like saying "you have a 1 in 101 chance of dying in a car accident, while only a 1 in 50,000 chance of dying in a wing suit accident" without mentioning the relative difference in average exposure.
I was comparing lifetime risks in which the exposure is across the average lifetime.

Just an FYI I also answered more points in your post but regardless of what I do the forum is placing the rest of my post inside the quote. So if you didn’t see it expand the quote. If you did no worries.
 

Paratus

Lifer
Jun 4, 2004
16,672
13,418
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What is the power envelope of ISS, assuming it is not classified.
Really depends on how to answer that.

Do you want beginning of life power generation where each of the 8 solar arrays can produce 31KW for 248kw total?

The limits we run each of the 8 channels at so we keep the total ISS power at or under ~ 100KW ?

The battery limits so each night pass doesn’t use more than a 1/3 of the battery power leaving at least 2/3rds for power failures?


The basic point I was trying to make is if you size your power generation and storage correctly, include fault tolerance and cross strapping capability along with the ability to loadshed and taking into account worst case loading and loss of power generation it’s possible to run critical system on nothing but renewables and storage.

Doing it on the ground presents other challenges and other benefits but it’s still fundamentally the same.
 
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woolfe9998

Lifer
Apr 8, 2013
16,188
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I have mentioned likelihood a lot, probability is basically all I've discussed in this thread.

But you can't say "see the worst case isn't that bad" when the only reason the worst case (so far) wasn't much worse is because of actions that would not happen here.

If you have evidence that a regional wide risk is impossible feel free to present it. If it isn't impossible, then we must decide what probability of that consequence we are willing to accept. I'm guessing most people would want that probability so low that the current experience would be no where close to enough to use the line "see it hasn't happened, therefore it won't."

I don't bother with "impossible." If you are experienced in risk analysis, you know that "possible" and "impossible" are irrelevant. Climate change is a certainy. It isn't merely possible.
 

Zorba

Lifer
Oct 22, 1999
14,526
9,899
136
I was comparing lifetime risks in which the exposure is across the average lifetime.

Just an FYI I also answered more points in your post but regardless of what I do the forum is placing the rest of my post inside the quote. So if you didn’t see it expand the quote. If you did no worries.
I didn't notice that, I'll go read the rest. I agree that what you were doing accounts for life time exposure, but stating it like that makes things with low exposures seem less risky than they actually are on a marginal basis.
 

Zorba

Lifer
Oct 22, 1999
14,526
9,899
136
I don't bother with "impossible." If you are experienced in risk analysis, you know that "possible" and "impossible" are irrelevant. Climate change is a certainy. It isn't merely possible.
Possible and impossible is not irrelevant in a risk analysis, if a consequence isn't credible it isn't evaluated generally. It's impossible for a car to irradiate a city so that consequence isn't considered.

So what is the actual worst case of a modern US reactor? If widespread contamination can't physically happen then build away. If it's wiping out large areas, we need to have an honest look at the probabilities and decide if it is worth losing large areas every now and then due to failures.
 

Moonbeam

Elite Member
Nov 24, 1999
72,409
6,080
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According to reason one in the Greenpeace link that states six reasons against a nuclear road, the first is this:

1. Nuclear energy delivers too little to matter
In order to tackle climate change, we need to reduce fossil fuels in the total energy mix well before 2050 to 0%.

According to scenarios from the World Nuclear Association and the OECD Nuclear Energy Agency (both nuclear lobby organisations), doubling the capacity of nuclear power worldwide in 2050 would only decrease greenhouse gas emissions by around 4%. But in order to do that, the world would need to bring 37 new large nuclear reactors to the grid every year from now, year on year, until 2050.

The last decade only showed a few to 10 new grid connections per year. Ramping that up to 37 is physically impossible – there is not sufficient capacity to make large forgings like reactor vessels. There are currently only 57 new reactors under construction or planned for the coming one-and-a-half decade. Doubling nuclear capacity – different from the explosive growth of clean renewable energy sources like solar and wind – is therefore unrealistic. And that for only 4% when we already need to reduce 100%.

So I ask myself what if this is true? What is the point of arguing whether people assess risk properly and means by which that stupidity will never be beaten out of them by those who want to shove nuclear down their ignorant throats, if we can’t build enough of them to prevent environmental disaster anyway.

Also, no matter how safe a nuclear reactor we can design, there is the real risk is sabotage. Very thoughtful of us to store juicy sticks of dynamite with detonators connected to the internet.

Talk about airline safety, yup. Save enough that partially trained people safely landed them into the Twin Towers.

But let’s just stick with point one. Is it a fact we can’t build even enough reactors to get a 4% reduction much less 100% soon enough to matter? If so, why bother with a risk analysis? Solar and wind and storage are already
 

Zorba

Lifer
Oct 22, 1999
14,526
9,899
136
I disagree.

Let’s compare two “risky” events. Like I already posted the lifetime risk of death by car accident is 1/101 (that’s a 5X5 on most Risk matrices). As you say the frequency of driving increases the risk.

Now let’s compare it to wingsuit flying. That has a risk of death of 1/500 flights. If you do it 10 times in your life that’s a lifetime risk of 1/50 or twice as likely.

Probabilistic Risk Assessment needs to take into account the likelihood a risk can occur and the frequency of exposure before two risks can be compared
I agree with you on what's in the nested quote. That is what I was attempting to say. We need a real policy decision using real data. Obviously not using nukes has serious guaranteed negative externalities. While operating nukes has low guaranteed externalities but much larger hazards. It's a trade.

The real problem is safe nuclear plants aren't economical to build or operate which is why literally no one builds them. Even if an accident is fully contained it's outrageously expensive to clean up.

One problem with all accidents is people point to one of issues and imply "see that can't/won't happen here/again," but all three accidents come back to humans and economic decisions.

Comparing realized deaths isn't really that great of a measure when talking of low probability of very high consequence events, especially when compared to high probability "lower" consequence events.

As an example, let's consider the number of deaths from conventional weapons vs nukes. Conventional weapons have killed millions in the last 50 years, nukes have killed basically none. So should we stop selling conventional weapons and start handing out nukes? More than likely less people would die, but one dumb move could kill millions as opposed a few with one conventional weapon.
 

Ajay

Lifer
Jan 8, 2001
15,434
7,850
136
According to reason one in the Greenpeace link that states six reasons against a nuclear road, the first is this:

1. Nuclear energy delivers too little to matter
In order to tackle climate change, we need to reduce fossil fuels in the total energy mix well before 2050 to 0%.

According to scenarios from the World Nuclear Association and the OECD Nuclear Energy Agency (both nuclear lobby organisations), doubling the capacity of nuclear power worldwide in 2050 would only decrease greenhouse gas emissions by around 4%. But in order to do that, the world would need to bring 37 new large nuclear reactors to the grid every year from now, year on year, until 2050.

The last decade only showed a few to 10 new grid connections per year. Ramping that up to 37 is physically impossible – there is not sufficient capacity to make large forgings like reactor vessels. There are currently only 57 new reactors under construction or planned for the coming one-and-a-half decade. Doubling nuclear capacity – different from the explosive growth of clean renewable energy sources like solar and wind – is therefore unrealistic. And that for only 4% when we already need to reduce 100%.

So I ask myself what if this is true? What is the point of arguing whether people assess risk properly and means by which that stupidity will never be beaten out of them by those who want to shove nuclear down their ignorant throats, if we can’t build enough of them to prevent environmental disaster anyway.

Also, no matter how safe a nuclear reactor we can design, there is the real risk is sabotage. Very thoughtful of us to store juicy sticks of dynamite with detonators connected to the internet.

Talk about airline safety, yup. Save enough that partially trained people safely landed them into the Twin Towers.

But let’s just stick with point one. Is it a fact we can’t build even enough reactors to get a 4% reduction much less 100% soon enough to matter? If so, why bother with a risk analysis? Solar and wind and storage are already
Well, firstly, we are not going to hit net zero in 2050 - that ship has already sailed (unless mother nature has another miracle hidden from us). Nuclear energy is useful as baseload capacity along with batteries to maintain constant power (according to needs) regardless of weather and climatic variations. 4th generation Nuclear Reactors have all be designed from the ground up to avoid all the safely issues with old tech PWR power plants. They don't need giant containment domes. So they are cheaper. Current plans are to build them in 100MW to 300MW capacities to allow faster turnaround times (they are built and certified much faster than GW PWRs so that inventor aren't just sitting around earning no income). There are designs out there that are shooting to be mini (sub 100 MW) and micro generators (sub 10 MW) to enable them to build in mass production factories.

The point is to take a multi-pronged approach to reducing our carbon output so that the combined efforts get us their faster. If that 4% number is true (and that's with older designs), that aint nothing! As with so many things regarding climate change - we had the chance to start earlier (those 4th gen nuclear design were already on the drawing board ~20 years ago). But, humans, ya know, we don't hit the brakes on a collapsing bridge till the a couple cars have clearly gone off the edge. Hmm, if only we had put up the money to just 'maintain' the damn thing.
 

Zorba

Lifer
Oct 22, 1999
14,526
9,899
136
I just want to add, I'm not anti-nuke plants in general. I don't think we should be shutting them down and replacing them with gas. I also think we should be reprocessing fuel and probably breeding. But I also understand if we go out and build 500 new PWRs we are increasing our risk of a major accident at least 5x, probably more as we stretch the NRC and add new operators and contractors to the equation. It's impact is also marginal if we don't also put them in India, Africa, etc, but will those places maintain high safety standards?

There are no silver bullets to climate change and replacing all base load with fission is about as likely as replacing it all with fusion at this point.

Driving real efficiency standards would have just as much impact, maybe more as building a realistic number of new reactors in the US.
 

Moonbeam

Elite Member
Nov 24, 1999
72,409
6,080
126
I just want to add, I'm not anti-nuke plants in general. I don't think we should be shutting them down and replacing them with gas. I also think we should be reprocessing fuel and probably breeding. But I also understand if we go out and build 500 new PWRs we are increasing our risk of a major accident at least 5x, probably more as we stretch the NRC and add new operators and contractors to the equation. It's impact is also marginal if we don't also put them in India, Africa, etc, but will those places maintain high safety standards?

There are no silver bullets to climate change and replacing all base load with fission is about as likely as replacing it all with fusion at this point.

Driving real efficiency standards would have just as much impact, maybe more as building a realistic number of new reactors in the US.
Rather likely the case:

https://sustainablesolutions.duke-energy.com/resources/net-zero-emissions/

I find the argument that we are alreqdy 20% of the way there with renewables interesting. A large percent of fossil fuel energy from burning and the corresponding emissions produced produce no electricity. Solar and wind do not have such waste.
 

Moonbeam

Elite Member
Nov 24, 1999
72,409
6,080
126
Well, firstly, we are not going to hit net zero in 2050 - that ship has already sailed (unless mother nature has another miracle hidden from us). Nuclear energy is useful as baseload capacity along with batteries to maintain constant power (according to needs) regardless of weather and climatic variations. 4th generation Nuclear Reactors have all be designed from the ground up to avoid all the safely issues with old tech PWR power plants. They don't need giant containment domes. So they are cheaper. Current plans are to build them in 100MW to 300MW capacities to allow faster turnaround times (they are built and certified much faster than GW PWRs so that inventor aren't just sitting around earning no income). There are designs out there that are shooting to be mini (sub 100 MW) and micro generators (sub 10 MW) to enable them to build in mass production factories.

The point is to take a multi-pronged approach to reducing our carbon output so that the combined efforts get us their faster. If that 4% number is true (and that's with older designs), that aint nothing! As with so many things regarding climate change - we had the chance to start earlier (those 4th gen nuclear design were already on the drawing board ~20 years ago). But, humans, ya know, we don't hit the brakes on a collapsing bridge till the a couple cars have clearly gone off the edge. Hmm, if only we had put up the money to just 'maintain' the damn thing.
Why would you want to produce more nuclear waste in a world that has been promising to store it safely since the inception of the industry and has not done so yet. Energy producers are interested in producing money for psychopaths. Since day one all the waste produced is exposed on the surface often in old leaking containers. You nuclear people are dreamers who have swallowed a bill of goods. You hope to turn all of the intelligently self interested NIMBYs by passing laws that shove the threat of poisoning down their throats. Bury your nuclear waste under federal, state, and local government buildings. There will be no push back from hypocrites like those selfish assholes in Nevada.
 

hal2kilo

Lifer
Feb 24, 2009
23,424
10,317
136
Hazards can sometimes be eliminated through substitution.
Until reality rears it ugly head and finds that the substitution is worthless. Seals in missile tubes come to mind. Oh, my they were using an acid based cleaner before, but you know acid is automatically bad. Early PCB cleaner substitutes sucked, but they did get better.
 

Moonbeam

Elite Member
Nov 24, 1999
72,409
6,080
126

Seems like a rather serious attempt to provide an objective answer. The conclusion, go renewable and avoid nuclear or nuclear renewable mixed as nuclear will slow down the achievement of the needed reductions arriving the fastest.
 

cytg111

Lifer
Mar 17, 2008
23,182
12,841
136
again


Plus there is not enough fission material to go around… If we go for the nuclear long term its really fusion or bust.
 

Moonbeam

Elite Member
Nov 24, 1999
72,409
6,080
126
again


Plus there is not enough fission material to go around… If we go for the nuclear long term its really fusion or bust.
While the argument is complex, especially when two powerful arguments against nuclear are removed from the table, it is pretty clear that for the US the right answer is renewables.
 

[DHT]Osiris

Lifer
Dec 15, 2015
14,088
12,180
146
Ya'll know we're already irradiating our planet by burning fossil fuels right? We're just not doing any cleanup, kicking that can down the road since it's quiet rather than being forced to clean it up because it was loud. Even including accidents, there's less radioactive contamination from fission reactors than coal plants.

That doesn't even include the smoking river of other contaminants given off by said coal plants.
 

Moonbeam

Elite Member
Nov 24, 1999
72,409
6,080
126
Ya'll know we're already irradiating our planet by burning fossil fuels right? We're just not doing any cleanup, kicking that can down the road since it's quiet rather than being forced to clean it up because it was loud. Even including accidents, there's less radioactive contamination from fission reactors than coal plants.

That doesn't even include the smoking river of other contaminants given off by said coal plants.
From my point of view so much of this thread misses the point, left brain technical, engineer thinking verses right brain holistic, humanistic thinking.

It should have nothing to do with the risks of fossil fuels verses anything else. The point is that the burning of carbon based materials for energy production is bringing us closer and closer to a titanic climate disaster and we have very little time left to prevent it. It threatens civilization and possibly human survival. The burning of fossil fuels must stop so the only relevant question is how to replace the needed energy they now supply.

There are two main alternatives, nuclear and renewables and into which massive efforts must be poured. That only renewables can and must win that race could not be more obvious to me. It's where all the acceleration is to be found as well as decreasing costs across the board. It is where the investment, talent, and plans are most being made. It is already happening. It is something the public puts on their roofs when they can afford it. It appeals to the conscious of parents who think of the future of their children. It can't be turned easily into a weapon or sabotaged to produce an ecological disaster. It does not need to be built next to oceans and rivers or use pipe corroding molten salts for cooling. The area used can have multiple uses including water efficient greenhouse pesticide free organic food. No toxic waste to dream one can safely store for tens of thousands of thousands of years.