My country is going to commit economic suicide ...

[apis]

According to Wikipedia electricity to Hydrogen conversion can be up to 95%. Modern fuel cells are in the 50% to 60% ballpark. When the waste heat it used a fuel cell can reach 85% efficiency.

IMHO you are seriously underestimating the cost of thousands of kilometers of electricity grid.

Wikipedia says it's currently 70-80% which is what the study used (75%), it also assumed fuel cell efficiency of 50% which sounds about right to me. On top of that you have compression and transport which uses energy.

You have to compare it to the cost of all of the hydrogen infrastructure. You need factories to produce the hydrogen and compress it and then you need containers to store it in, and finally trucks/boats/trains to transport it physically. You also have to account for some losses. On top of that you have to have people working in those factories, ships, trucks, etc. Compare that to a cable and I bet the cable is cheaper, but I haven't done any calculations.

[nctnico]

I have not read it thouroughly but this document seems to have a nice summary of costs and losses in electricity grids:
https://iea-etsap.org/E-TechDS/PDF/E12_el-t&d_KV_Apr2014_GSOK.pdf

[apis]

Maybe this snipped from an old documentary will convince you. Note the quote by Vassili Nesterenko, a top nuclear physicist who was present at the site. "Our experts studied the possibility and concluded that the explosion would have had a force of 3-5 megatonnes. Minsk, which is 320km from Chernobyl, would have been razed, and Europe rendered uninhabitable." This is seconded by Mikhail Gorbachev. I assume you know who he is and how well informed he would have been.

It really surprises me how many people feel they know better, based on I'm not sure what exactly.

I talked to a nuclear physicist here in Sweden who's an expert on nuclear weapons and who has studied the Chernobyl disaster. He explained that an explosion in the megaton class was completely impossible. The biggest fission bomb humans have designed or detonated was 500 kiloton, to get more you need a fusion bomb and there isn't even the right elements in a nuclear reactor for that. A bomb also need very special configurations in order for it to detonate and it would be impossible for that to happen by chance. That documentary makes no sense what so ever, it's a perfect example of the scaremongering I've been talking about.

A steam-explosion is just what it sounds like, the heat from the molten core might have created more steam, which if confined could cause a pressure buildup and a sudden rupture could then potentially have spread some more debris locally around the reactor. The initial explosion was much more powerful though, possibly powered by a nuclear chain reaction (although not an explosion like in a bomb). The fuel was located in vertical tubes and the roof of the building was made of wood and tar-paper (it was supposed to be concrete). The result was that the initial explosion shot radioactive material high up into the atmosphere like a gigant nuclear cannon. A second explosion caused by built up steam pressure then further destroyed the reactor. If there had been a third steam explosion in the basement it could perhaps have made things a little worse but not by much.

I'll attach a report with an analysis of what risk the molten core poses after the accident. The main danger is that if it comes in contact with too much water the nuclear reaction can restart, increasing the radioactivity and heat output, however it will only last until the water is boiled away again (there is zero risk of a nuclear explosion). That could cause more problems locally so it's undesirable and why they have built a new cover over the accident site.

Interestingly there was a naturally ocuring nuclear reactor in central Africa where this occurred over a period of a few hundred thousand years:
https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor

As for what politicians think: Hans Blix was the head of the International Atomic Energy Agency at the time of the Chernobyl disaster. As such, Blix was the first Western representative to inspect the consequences of the Chernobyl disaster in the Soviet Union on site.
https://en.wikipedia.org/wiki/Hans_Blix

Here is a opinion piece by him from 2007 where he argues for more nuclear power:
https://translate.google.com/translate?hl=&sl=sv&tl=en&u=http%3A%2F%2Fwww.fokus.se%2F2007%2F05%2Fhans-blix-karnkraft-ja-tack%2F
If any politician was well informed about what was going on at the time it would have been him.

[Mr. Scram]

I talked to a nuclear physicist here in Sweden who's an expert on nuclear weapons and who has studied the Chernobyl disaster. He explained that an explosion in the megaton class was completely impossible. The biggest fission bomb humans have designed or detonated was 500 kiloton, to get more you need a fusion bomb and there isn't even the right elements in a nuclear reactor for that. A bomb also need very special configurations in order for it to detonate and it would be impossible for that to happen by chance. That documentary makes no sense what so ever, it's a perfect example of the scaremongering I've been talking about.

A steam-explosion is just what it sounds like, the heat from the molten core might have created more steam, which if confined could cause a pressure buildup and a sudden rupture could then potentially have spread some more debris locally around the reactor. The initial explosion was much more powerful though, possibly powered by a nuclear chain reaction (although not an explosion like in a bomb). The fuel was located in vertical tubes and the roof of the building was made of wood and tar-paper (it was supposed to be concrete). The result was that the initial explosion shot radioactive material high up into the atmosphere like a gigant nuclear cannon. A second explosion caused by built up steam pressure then further destroyed the reactor. If there had been a third steam explosion in the basement it could perhaps have made things a little worse but not by much.

I'll attach a report with an analysis of what risk the molten core poses after the accident. The main danger is that if it comes in contact with too much water the nuclear reaction can restart, increasing the radioactivity and heat output, however it will only last until the water is boiled away again (there is zero risk of a nuclear explosion). That could cause more problems locally so it's undesirable and why they have built a new cover over the accident site.

Interestingly there was a naturally ocuring nuclear reactor in central Africa where this occurred.
https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor

As for what politicians think: Hans Blix was the head of the International Atomic Energy Agency at the time of the Chernobyl disaster. As such, Blix was the first Western representative to inspect the consequences of the Chernobyl disaster in the Soviet Union on site.
https://en.wikipedia.org/wiki/Hans_Blix

Here is a opinion piece by him from 2007 where he argues for more nuclear power:
https://translate.google.com/translate?hl=&sl=sv&tl=en&u=http%3A%2F%2Fwww.fokus.se%2F2007%2F05%2Fhans-blix-karnkraft-ja-tack%2F
If any politician was well informed about what was going on at the time it would have been him.

You have to understand that an opinion reportedly relayed from an unnamed and unknown nuclear weapons expert not going on record who doesn't appear to have been on site isn't going to counter a third party video with a internationally renowned expert going on record after having been part of the investigation on site himself. As far as I can tell has Hans Blix never made any statements directly contradicting the secondary steam explosion disaster nearly happening. Maybe it's time to concede you may have overlooked some historical facts. There's really no shame in that.

[nctnico]

A quick Google turned up there is a yield limit on fission bombs which is well below the 1Mton range. Perhaps it is better to do some fact checking yourself before deciding something isn't true based on... what exactly?

The largest pure-fission bomb ever constructed, Ivy King, had a 500 kiloton yield,[2] which is probably in the range of the upper limit on such designs.[citation needed] Fusion boosting could likely raise the efficiency of such a weapon significantly, but eventually all fission-based weapons have an upper yield limit due to the difficulties of dealing with large critical masses. (The UK's Orange Herald was a very large boosted fission bomb, with a yield of 750 kilotons.) However, there is no known upper yield limit for a fusion bomb.

From:
https://en.wikipedia.org/wiki/Nuclear_weapon_yield

[Mr. Scram]

A quick Google turned up there is a yield limit on fission bombs which is well below the 1Mton range. Perhaps it is better to do some fact checking yourself before deciding something isn't true based on... what exactly?

The largest pure-fission bomb ever constructed, Ivy King, had a 500 kiloton yield,[2] which is probably in the range of the upper limit on such designs.[citation needed] Fusion boosting could likely raise the efficiency of such a weapon significantly, but eventually all fission-based weapons have an upper yield limit due to the difficulties of dealing with large critical masses. (The UK's Orange Herald was a very large boosted fission bomb, with a yield of 750 kilotons.) However, there is no known upper yield limit for a fusion bomb.

From:
https://en.wikipedia.org/wiki/Nuclear_weapon_yield

Based on the video recorded testimony of a nuclear expert who has been part of the investigation on site. I'm not sure you're entirely aware of the nature of the explosion which was prevented.

https://www.eevblog.com/forum/renewable-energy/my-country-is-going-to-commit-economic-suicide/msg2071906/#msg2071906

[apis]

Maybe it's time to concede you may have overlooked some historical facts. There's really no shame in that.

Maybe you will one day realise the irony of what you just wrote.

No one is going to write anything official or take the trouble of going on record just to refute what that guy said, because a silly documentary isn't taken serious by professionals. But as ntcnico said, you can Google and see for yourself that what he said can not possibly be true.

[nctnico]

A quick Google turned up there is a yield limit on fission bombs which is well below the 1Mton range. Perhaps it is better to do some fact checking yourself before deciding something isn't true based on... what exactly?

The largest pure-fission bomb ever constructed, Ivy King, had a 500 kiloton yield,[2] which is probably in the range of the upper limit on such designs.[citation needed] Fusion boosting could likely raise the efficiency of such a weapon significantly, but eventually all fission-based weapons have an upper yield limit due to the difficulties of dealing with large critical masses. (The UK's Orange Herald was a very large boosted fission bomb, with a yield of 750 kilotons.) However, there is no known upper yield limit for a fusion bomb.
From:
https://en.wikipedia.org/wiki/Nuclear_weapon_yield

Based on the video recorded testimony of a nuclear expert who has been part of the investigation on site. I'm not sure you're entirely aware of the nature of the explosion which was prevented.

https://www.eevblog.com/forum/renewable-energy/my-country-is-going-to-commit-economic-suicide/msg2071906/#msg2071906

Again some Googling can easely debunk that: https://en.wikipedia.org/wiki/Thermonuclear_weapon A nuclear fusion bomb has a very special construction and uses all kind of materials likely not present in the right shape & amount in a molten nuclear reactor. All in all it is very likely there is an error in the translation from Russian to English. 0.2 to 0.3 Megatonnes would be a number within the realm of possibilities given the reaction would be fission only.

Perhaps someone fluent in Russian could listen and transcribe what the expert is saying.

Edit: I hope I'm not flagged for looking up information on nuclear bombs... 

[Mr. Scram]

Maybe you will one day realise the irony of what you just wrote.

No one is going to write anything official or take the trouble of going on record just to refute what that guy said, because a silly documentary isn't taken serious by professionals. But as ntcnico said, you can Google and see for yourself that what he said can not possibly be true.

It literally doesn't get much better than video expert testimony. Flat out denying its relevance isn't going to cut it. Please understand that the explosion prevented was dangerous due to the interaction with the water.

[Mr. Scram]

Again some Googling can easely debunk that: https://en.wikipedia.org/wiki/Thermonuclear_weapon A nuclear fusion bomb has a very special construction and uses all kind of materials likely not present in the right shape & amount in a molten nuclear reactor. All in all it is very likely there is an error in the translation from Russian to English. 0.2 to 0.3 Megatonnes would be a number within the realm of possibilities given the reaction would be fission only.

Perhaps someone fluent in Russian could listen and transcribe what the expert is saying.

Edit: I hope I'm not flagged for looking up information on nuclear bombs... 

I've been looking for a rapport which may have been the source of this specific claim, but I haven't been able to dig it up so far. I can't rule out errors in translation, but the described impact of said explosion seems reasonably consistent with the numbers and that entire part being mistranslated seems increasingly unlikely. I can imagine we're not understanding the proposed mechanism through which this explosion would occur. Either way, even a 0.2 to 0.3 megaton explosion would have been a massive disaster. That secondary explosion would have dwarfed what we came to know as the Chernobyl disaster. Despite how bad it already was, we had a lucky escape.

[apis]

Maybe you will one day realise the irony of what you just wrote.

No one is going to write anything official or take the trouble of going on record just to refute what that guy said, because a silly documentary isn't taken serious by professionals. But as ntcnico said, you can Google and see for yourself that what he said can not possibly be true.

It literally doesn't get much better than video expert testimony. Flat out denying its relevance isn't going to cut it. Please understand that the explosion prevented was dangerous due to the interaction with the water.

If you think it doesn't get better than a heavily edited and translated interview in a TV "documentary" then you have a pretty scary attitude to facts. At most such a clip could serve as inspiration for further investigations. Maybe you should look up what a peer reviewed scientific journal is.

Of course it was about interaction with water, steam is water in the gas-phase, that is why they talk about a steam-explosion. That is very different from a nuclear fusion bomb.

I've been looking for a rapport which may have been the source of this specific claim, but I haven't been able to dig it up so far.

Yet you keep insisting you know better than every one else. Maybe it's time to take your own advice and concede you might have been wrong, there is no shame in that, only in insisting you are right in spite of overwhelming evidence of the contrary.

And no, there was never a possibility of a 0.2 megaton, or xx kiloton, or any form of nuclear explosion according to the nuclear weapons expert I talked to.

Besides, it's just common sense, if it was that easy to create a fusion bomb do you think e.g. North Korea or Iran would have so much trouble trying to build them?

Do you seriously think any politician, e.g. Gorbachev or Blix, would support nuclear power in their country if there was a real risk they would explode in a 3 megaton nuclear explosion? Both Russia and Sweden still has nuclear reactors and Hans Blix at least thinks we should have more. And apparently so does Putin: "The Russian energy strategy of 2003 set a policy priority for reduction in natural gas based power supply, aiming to achieve this through a doubling of nuclear power generation by 2020." https://en.wikipedia.org/wiki/Nuclear_power_in_Russia.

[Mr. Scram]

If you think it doesn't get better than a heavily edited and translated interview in a TV "documentary" then you have a pretty scary attitude to facts. At most such a clip could serve as inspiration for further investigations. Maybe you should look up what a peer reviewed scientific journal is.

Of course it was about interaction with water, steam is water in the gas-phase, that is why they talk about a steam-explosion. That is very different from a nuclear fusion bomb.

That's why I've been looking for the rapport which apparently goes along with the statements. This entire discussion is whether Chernobyl was close to becoming a much larger disaster and there isn't anything contradicting this. The story has been coherent from the beginning and claims it's some kind of manufactured story don't seem viable. I really don't understand why such a big deal is made out of it either. It's not as if the entire story of nuclear power having the potential of becoming large scale disasters hinges on it. It's good to be aware of as it gives a better perspective of what we're dealing with, but it's hardly worth going to war over.

[nctnico]

But people have to keep in mind that nuclear power plants which are constructed nowadays are build with the 'lessons learned' from dissasters and near-dissasters in the past. This doesn't guarantee nothing will ever go wrong again but the risk is extremely low.

[apis]

I really don't understand why such a big deal is made out of it either.

Because it is a lie. It is important that we base our decisions on facts or else we will make incorrect and even harmful decisions (like many have already by choosing coal instead of nuclear). If nuclear power reactors could blow up like nuclear bombs then no one in their right mind would use them or work in them or live near them. What happened at Chernobyl is pretty much the worst that could happen.

Now that we have a lot of research showing what the consequences was and it turns out nuclear power is far less harmful to peoples health and the environment than e.g. coal power or even hydro power. So the anti-nuclear activists are now pretending "oh, but but it could have been much worse". That is just dishonest and downright dangerous.

[Mr. Scram]

But people have to keep in mind that nuclear power plants which are constructed nowadays are build with the 'lessons learned' from dissasters and near-dissasters in the past. This doesn't guarantee nothing will ever go wrong again but the risk is extremely low.

Are there any charts which show the age and design type of various reactors around the world?

[Mr. Scram]

Because it is a lie. It is important that we base our decisions on facts or else we will make incorrect and even harmful decisions (like many have already by choosing coal instead of nuclear). If nuclear power reactors could blow up like nuclear bombs then no one in their right mind would use them or work in them or live near them. What happened at Chernobyl is pretty much the worst that could happen.

You can't will it to be untrue because it doesn't suit your narrative. We could argue all day long what the actual scale of the secondary explosion would have been, but even very conservative estimates mean the plant would have sustained massive damage and huge amounts of radioactive materials would have been ejected into the world. That still fits the original statement that Chernobyl has been a disaster prevented. There's a reason modern Russian plants are built with floors designed to prevent exactly this from happening. They do this because it almost did happen.

Again, I don't understand why you make such a big deal even out of something so irrelevant to your argument. It hurts your credibility if you flat out refuse to concede anything which isn't favourable for your position, especially in the face of the evidence presented. No amount of evidence is going to change anything as it'd just lead to mental gymnastics and more denial, so yet again I'm going to end the discussion here.

[nctnico]

I really don't understand why such a big deal is made out of it either.

Because it is a lie. It is important that we base our decisions on facts or else we will make incorrect and even harmful decisions (like many have already by choosing coal instead of nuclear).

I wouldn't call it an outright lie because if the molten Uranium would have reached the water a chain reaction with unknown proportions could have taken place. I'm not sure if that would result in a really big explosion in the hundreds of kiloton range. First of all the amount of material wouldn't be very big because it would have leaked like lava through the floor, secondly the material would be very contaminated with whatever is dissolved in it (steel, concrete, whatever) and thirdly the water would be boiled and/or blown away. Maybe the explosion would be in the several kiloton range. Still enough to likely spread a lof of radioactive material over the surrounding area and make cleaning up the mess more difficult than it is. Also the neighbouring reactors could be affected leading to multiple reactors with a melt-down. All in all it seems to me that preventing an explosion below the reactor was extremely important but not because it could result in a massive atomic blast. The damage of even a small explosion could be tremendous.

[Kleinstein]

The fuel in most reactor is considered not suitable to create a nuclear explosion, without an extraordinary effort. This criterion is used by the IAEO if material to be safe to be handled by non weapons states.
So it is essentially impossible that this would happen by accident. If there is an obscure TV report claiming such things - the logical thing it to have a good laugh    and ignore those "experts", not matter why they claim they are experts. Jut put them in the same box as those claiming martians are coming next week.

When the initial explosion happened  the fuel elements where still essentially intact. So while it was a significant explosion, that could have also damaged a heavy concrete roof, there was not that much radioactivity coming out. The isotopes found in much of Europe also showed that this where mainly the rather mobile elements, essentially no uranium or plutonium.

With the molten fuel reaching water, there was a danger (not sure for it to happen)  to get another smaller steam-explosion, but now with heavily damaged fuel and thus possibly more radioactive material (especially also the heavy metals). Even if the nuclear reaction would restart, this would be slow and usually limited by the water boiling off, or super hot fuel pushed away. The nice thing about a water moderated reactor is that formation of steam kind of stabilizes the reaction.

[cdev]

The radioactive materials found in Japan after Fukushima are proving to be problematic, because randomly distributed in the dust there is a small but highly radioactive component of particles that emit gamma radiation and stay radioactive for a very long time.


Press Release: Radioactively-Hot Particles in Japan — Nuclear Energy Education
https://www.fairewinds.org/newsletter-archive//press-release-radioactively-hot-particles-in-japan

[IanMacdonald]

An enriched natural uranium (mostly U238 with a  few percent of U235) reactor cannot undergo a fission explosion of any size, and that is because U238's capture cross-section for fast neutrons is too large.  Fast neutrons typically get captured by U238 atoms before they reach the few U235 atoms present. The U238 atoms are transmuted (Mostly to PU239) but do not release a cascade of fast neutrons, so the process is not self-sustaining. 

A sustained reaction can only take place if there is a moderator present such as graphite or water. This slows the neutrons into the 'thermal' kinetic energy range. The slow neutrons don't greatly interact with U238, and hence continue until they reach a U235 atom. Where they cause fission, releasing 3 more fast neutrons. And, so on.

Remove the U238 and the moderator is no longer needed. Then, a fission explosion is possible. It still requires fast assembly though, otherwise the heat produced as the material becomes 'critical' and intensely radioactive will just result in a meltdown and disintegration.

The main explosion risk in commercial reactors, and the likely cause of the explosions at Chernobyl and Fukushima, is zirconium fuel pin cladding burning in steam or water, which releases hydrogen. Zirconium is chosen for its low neutron absorbtion combined with good physical strength. It is a metal, similar to magnesium. Like magnesium it is inflammable, but quite hard to ingite. Once ignited though, it burns furiously and is hard to extinguish. If the burning metal comes into contact with water it robs the oxygen, leaving hydrogen gas. Hydrogen is explosive over a very wide range of mixtures with air. It takes only a tiny spark to ignite a hydrogen/air mixture, and if in a strong confined vessel such as a containment building, the resulting explosion is powerful. In this case the strong building works against itself, leading to an even bigger bang.

The world's nuclear industry urgently needs to move away from designs using zirconium fuel cladding. This is by far the greatest safety risk in existing reactors. It turns a meltdown and local, manageable, contamination into a disaster area with pollution spread for miles around.   

[Mr. Scram]

The fuel in most reactor is considered not suitable to create a nuclear explosion, without an extraordinary effort. This criterion is used by the IAEO if material to be safe to be handled by non weapons states.
So it is essentially impossible that this would happen by accident. If there is an obscure TV report claiming such things - the logical thing it to have a good laugh    and ignore those "experts", not matter why they claim they are experts. Jut put them in the same box as those claiming martians are coming next week.

When the initial explosion happened  the fuel elements where still essentially intact. So while it was a significant explosion, that could have also damaged a heavy concrete roof, there was not that much radioactivity coming out. The isotopes found in much of Europe also showed that this where mainly the rather mobile elements, essentially no uranium or plutonium.

With the molten fuel reaching water, there was a danger (not sure for it to happen)  to get another smaller steam-explosion, but now with heavily damaged fuel and thus possibly more radioactive material (especially also the heavy metals). Even if the nuclear reaction would restart, this would be slow and usually limited by the water boiling off, or super hot fuel pushed away. The nice thing about a water moderated reactor is that formation of steam kind of stabilizes the reaction.

The man interviewed was one of the lead experts on site at the time of the disaster. Note that that documentary isn't the only source of the story either. It's been well documented and supported by other surrounding facts. This just happens to be a recording of the actual expert saying it himself.

[apis]

The biggest nuclear explosion that North Korea has been able to create after several decades is estimated to be 10 kiloton. To say you can create a 2-3 megaton explosion (or kiloton for that matter) by simply dropping some fuel-waste mixed with concrete into water is just plain ridiculous.

At most there could have been a steam buildup in the basement which could possibly have spread more heavily contaminated material around the accident site. But it would not have affected areas far away from Chernobyl. I would guess it might have made the exclusion zone a little more contaminated and made the cleanup around the reactor building more difficult. It was also quite possibly a direct threat to the personnel working at the site after the accident. So of course it would have been important to prevent that from happening. But it wouldn't have made the overall outcome much worse.

[Mr. Scram]

The biggest nuclear explosion that North Korea has been able to create after several decades is estimated to be 10 kiloton. To say you can create a 2-3 megaton explosion (or kiloton for that matter) by simply dropping some fuel-waste mixed with concrete into water is just plain ridiculous.

At most there could have been a steam buildup in the basement which could possibly have spread more heavily contaminated material around the accident site. But it would not have affected areas far away from Chernobyl. I would guess it might have made the exclusion zone a little more contaminated and made the cleanup around the reactor building more difficult. It was also quite possibly a direct threat to the personnel working at the site after the accident. So of course it would have been important to prevent that from happening. But it wouldn't have made the overall outcome much worse.

Expert > apis. The point is and has been all along that Chernobyl could have easily been a worse disaster and that's what you finally admit in this post. Not wholeheartedly, but it'll have to do. Now can be please be done with this senseless discussion over what's essentially a footnote? It doesn't change the fact that nuclear power has the potential to cause massive disasters one way or another.

[cdev]

It seems to me to potentially be even more destructive over time if the explosion is non-nuclear but releases large amounts of gamma-ray emitting highly radioactive particles with very long half lifes. Which is what happened in several nuclear accidents although the thread here seems to not be engaging on that.

The media hasn't covered this but there are a large number of these particles in Japan, where a lot of people now have their own personal radiation detecting equipment. There is this usual black gunk alongside roads everywhere in the world which -now in Japan, it turns out has often been acting as a sponge it seems for these gamma-ray emitting particles that clearly originated in Fukushima. They are clearly from a non-natural source. They're very dangerous, even if they are very small because they can and do initiate cancers. If they exist as part of the soil in an area, thats potentially a health problem for a long time unless its laboriously removed. Kind of like in "A Handmaid's Tale".

(Some parts of Japan have fairly high natural radioactivity levels, but thats not what I am talking about here)

Also apis, I think you're significantly understating the yields of nuclear tests in the DPRK. Nuclear terrorism is a serious risk, and proliferation risk is worsened by increases in the use of nuclear power.

[nctnico]

Now can be please be done with this senseless discussion over what's essentially a footnote? It doesn't change the fact that nuclear power has the potential to cause massive disasters one way or another.

But you'd have to agree that using fossile fuels have also caused massive dissasters. Think about acid rain and smog.

In 1954 over 10000 people died and 100000 got sick due to smog in London:
https://en.wikipedia.org/wiki/Great_Smog_of_London
To kill and injure a similar amount of people in one go you'd need a small atomic bomb. There probably isn't any other single weapon which can cause this much damage to a population of a city.