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The one thing I still wonder is whether SMRs could create a security nightmare. Every nuclear power plant is a fantastic target for terrorists. Transports of n

The one thing I still wonder is whether SMRs could create a security nightmare. Every nuclear power plant is a fantastic target for terrorists. Transports of nuclear waste are a fantastic target, too. I read once that the UK has many nuclear waste trains driving all the time, most of them empty, just to make it hard to guess which one to hit. (I assume other western countries have the same system). That kind of security doesn’t scale well. How do you protect infrastructure with many SMRs?

BlueTemplar 3y ago
I am more concerned about when/if we have millions of small nuclear reactors around, some of them will end up abandoned/lost. Then many years later, they will start to leak (think rain getting in).
- samus 3y ago
  Unlikely, that would imply a major breakdown of civilization. They are all connected to power lines, else they would not have been installed in the first place.
  - BlueTemplar 3y ago
    Well yes, major breakdowns of civilization have happened before and will happen again. There's one going on right now on the Ukraine/Russia border !
    - samus 3y ago
      And we saw what happens when nuclear installations are caught behind frontlines. In such situations, installations composed of SMRs would have advantages. For example, artillery blowing one up would be quite gnarly still, but less so than if that happened to a much larger monolithic plant!
  - gambiting 3y ago
    I mean during cold war many RTGs were deployed in remote regions of the world and subsequently lost. We even know of some cases where random people came across them and opened them up(unknowingly killing themselves in the process).
    - samus 3y ago
      SMR won't deployed to remote locations and then forgotten though. They will be installed and managed like usual nuclear installations: at dedicated sites, with appropriate security, and close supervision. Their purpose is to make these installations more modular and thus cheaper to maintain, extend, upgrade, and ultimately to decommission.
      - BlueTemplar 3y ago
        And yet before this I kept seeing publications about how they can be packed in a few containers/trailers and delivered anywhere to start producing heat/power... I guess it might have been about a different company, but you can understand my worries ? Also comes to mind the previous recklessness of some : while the USA has judged the use of "full blown" nuclear reactors in space too dangerous, the USSR launched 33 of them, 3 of which accidentally fell back to Earth, one contaminating a chunk of Canada. They even seemed to have kept launching them after Chernobyl, though that might have been inertia ? https://en.wikipedia.org/wiki/US-A https://en.wikipedia.org/wiki/US-A
        samus 3y ago
        Just because it could be deployed almost anywhere, doesn't mean it will. Just like with rental housing containers that could be ordered to be shipped anywhere a road leads to. We will likely see more nuclear installations though due to the fact that they don't have to be gargantuan to scale with the engineering costs. But they will be subject to the same regulatory regime that governs the existing installations.
naasking 3y ago
Switch to a thorium fuel cycle so virtually all of the fissionable material is spent, rather than 90+% of it remaining in the waste.
- perlgeek 3y ago
  Somehow, Thorium has been the future of nuclear reactors about as long as fusion has been. It's almost a running gag. (And yes, I know that there are concrete plans for commercial Thorium fission reactors, in a way that aren't for fusion, but still no fully-operating, commercial reactor, afaict).
  - AnthonyMouse 3y ago
    That's not really saying much given the number of new nuclear reactors of any fuel source the west has built in the current century. You have to build something in order to build something that runs on Thorium.
- LorenPechtel 3y ago
  Just use breeder reactors. Somebody repurposing the plutonium? No. Plutonium is not plutonium. For a bomb you need Pu-239. The more Pu-240 in your material the harder it is to slam the pieces together fast enough to avoid a premature chain reaction from robbing your bomb of most of it's power. For both bomb-making and fuel breeding the desired reaction is U-238 + n => U-239, decays to Np-239, decays to Pu-239. There is also the reaction Pu-239 + n => Pu-240. The power guys don't care, Pu-240 works fine. The bomb guys do care. Thus the power guys leave the fuel in the reactor until too much neutron poison builds up. The bomb guys leave the fuel in the reactor only a short time.
gadders 3y ago
Hire more of these people? https://www.gov.uk/government/organisations/civil-nuclear-constabulary/about https://www.gov.uk/government/organisations/civil-nuclear-co... "The Civil Nuclear Constabulary (CNC) is the armed police force in charge of protecting civil nuclear sites and nuclear materials in England and Scotland."
credit_guy 3y ago
> Every nuclear power plant is a fantastic target for terrorists. It is not. Let's say you are a terrorist, and you and your team have taken hold of a nuclear power plant. Then what? It's a problem for the world, but not different from you taking over a hotel or a city hall. You might threaten or even kill hostages, but there's no way you can create a significant nuclear threat. Let's say you force an operator, at gunpoint, to remove some rods from the reactor, or otherwise you get possession of some nuclear material. So what? How are you going to get away? You will be surrounded by hundreds or thousands of SWAT officers. What is the scenario where it will make a difference if they take over the nuclear power plant vs a different building?
- naasking 3y ago
  The point is that they could potentially abscond with nuclear material before being surrounded, obviously.
  - inglor_cz 3y ago
    Handling nuclear material straight out of the reactor is a good way to kill yourself very painfully.
    - naasking 3y ago
      Sure, but if we're talking about terrorists that a documented history of being willing to blow themselves up, I don't see why they wouldn't do this too. To avoid the painful death, blow yourself up after absconding but before radiation poisoning really takes its toll.
      - throwway120385 3y ago
        We're talking about people with EG civil engineering degrees masterminding these plots. The middle-eastern terrorists of yesteryear are not necessarily uneducated. Osama Bin Laden was educated as an engineer in the US and likely would have thought through the endgame and implications of such a plot well before executing it. These people are not stupid and would likely know what they are getting in to. I'd be more worried about a single unhinged person, but that's why we have security guards, and the problem would likely solve itself in short order in that case.
3D30497420 3y ago
My issue with thinking like this is that there are plenty of targets for terrorists: packed trains, stealing a big truck, etc. The fact that these events are pretty rare suggests that there aren't nearly as many terrorists as people seem to be worried about. Every power generation method has its plusses and negatives. I don't know if the risk from an SMR incident outweighs other methods, but it sounds promising. We certainly need an alternative to sources we know are bad (coal, oil, etc).
- psunavy03 3y ago
  Western society in general is a bunch of future cancer and heart disease victims all freaking out that they're going to die in a nuclear meltdown, or by the hand of a terrorist, or by a lone gunman "mass shooter," or in a plane crash, or any number of other threats that are scary but statistically highly unlikely. Human beings are just utter crap at intuitively estimating risk.
  - throw0101c 3y ago
    > Western society in general is a bunch of future cancer and heart disease victims all freaking out that they're going to die in a nuclear meltdown […] Also, COVID (to round out the top three in many places).
    - appointment 3y ago
      COVID has killed 7 million people since 2019. Airliner* crashes killed 80 people in 2023. These risks are not of the same class. * admittedly I'm exaggerating slightly by not considering private and military aviation, but I'm too lazy to find that total.
      - sidewndr46 3y ago
        The difference is you can trivially avoid death by airliner crash. You can't practically reduce your chance of death by COVID unless you simply never go outdoors or have visitors
chasil 3y ago
Ideally, the reactor is designed in such a way that a catastrophic failure is not possible. Something along the lines of the salt plug in a molten salt reactor, that melts when cooling fails and dumps the liquid into a boron bath, halting fission.
areoform 3y ago
Getting to the material is mechanically difficult. It's also the type of problem that neatly solves itself. A fuel rod toting terrorist is a dead terrorist. > The acceptance criteria in DSRS Section 12.3–12.4 state that accessible portions of the facility that are capable of having radiation levels greater than 1 Gy/h (100 rads/h) should be shielded and clearly marked with a sign stating that potentially lethal radiation fields are possible. DCA Part 2, Tier 2, Revision 3, identifies a number of areas (e.g., resin demineralizers, filters, SRSTs) that may contain quantities of radioactive material resulting in radiation dose rates exceeding 100 rads/h (1 Gy/h). Now what I'm about to say changes with the fuel being used, but from LLNL's report, > Even for fuel that has cooled for 15 years, a lethal dose (LD50) of 450 rem can be received at 1m from the fuel assembly after several minutes. https://www.osti.gov/servlets/purl/10137382 https://www.osti.gov/servlets/purl/10137382 Good luck trying to carry that stuff out. They'll be the walking dead in a few minutes. They'll be unable to walk and will be just dead in ~100 minutes. Give or take 10 to 20 minutes depending on how they're holding the item etc. https://en.wikipedia.org/wiki/Acute_radiation_syndrome#Dose_effects https://en.wikipedia.org/wiki/Acute_radiation_syndrome#Dose_... And no, they can't just "put it in [a] lead [box]" to run away with it, because then they'll die to bremsstrahlung radiation or braking radiation. It'll take longer, but the end result will be the same. If it's fuel that hasn't gone into the reactor yet/hasn't undergone neutron activation, then it's not radioactive enough to be a concern unless consumed. Terrorists are rare and they're usually not that capable. It's easier for them to buy a gun or a lorry and mow down a crowd than it is to plan a fiendishly complicated radiation heist.
- giva 3y ago
  I just want to point out that a terrorist that drives a plane into a skyscraper is a dead terrorist too. You need one terrorist to extract the material and put some quantities in a somewhat shielded container before being incapacitated, and then others to spread it on the subway.
  - areoform 3y ago
    Radiation isn't magic. Several feet/meters of water are used as shielding for the fuel for a good reason. If you put an activated fuel rod inside of a lead lunch box, you will still die. You will now die from a lethal dose of bremsstrahlung. https://en.wikipedia.org/wiki/Bremsstrahlung https://en.wikipedia.org/wiki/Bremsstrahlung If you interact with this material as an amateur without processes, robotics and safety, you will die. Period. You will also suffer from intense nausea and be unable to move before you die. Sharks with lasers are more realistic than this concern. The more plausible scenario is a "dirty bomb" that spreads depleted uranium particles everywhere and gives people cancer long-term. But there's an element of impracticality to this and there's a reason why it hasn't happened yet.
mytailorisrich 3y ago
I expect SMRs would be protected as standard nuclear plants are. Therefore, these are not easy targets and we've seen that they are very easy targets everywhere that will have the desired effect.
ElectronCharge 3y ago
I like the idea of siting them underground, which completely addresses the aircraft strike vulnerability. Physical security is also easy when they're underground. Thorcon was pursuing this, but has switched to a ship-based approach. Searching today, I found a new (to me at least) company that's working on a truly small reactor, 3-15 MW electricity, and is planning on underground siting: https://www.usnc.com/mmr/ https://www.usnc.com/mmr/ It also supplies 10-45 MW of thermal, so great for poleward climes. Fission will be a critical technology going forward, until fusion generation can compete on power to size/weight ratio...and cost. And until aneutronic fusion power is practical, there's no large benefit to fusion regarding waste.
jszymborski 3y ago
SMRs feel like a much worse target from what I understand. I'm no expert, but my understanding 1) SMRs are typically designed to be walk-away safe. Their smaller capacity means its harder for them to go critical in a spectacular way. [0] 2) Distributed targets are hard to respond to, but they're also hard to hit in an impactful way. Instead of having to hit one giant nuclear plant which supplies an entire regions energy, you have to hit many much smaller targets which supply much less energy. [0] https://www.forbes.com/sites/jamesconca/2018/01/24/can-we-make-a-nuclear-reactor-that-wont-melt-down/ https://www.forbes.com/sites/jamesconca/2018/01/24/can-we-ma...
- Retric 3y ago
  Getting it critical is a long way from the worst thing you can do with access to one or more SMR. However, nobody is going to be using these things individually. You still need a steam turbine, and cooling tower etc. So the general assumption is people will be using 10+ of these things and the added complexity would be offset by economies of scale.
AnthonyMouse 3y ago
> The one thing I still wonder is whether SMRs could create a security nightmare. People are going to tell you why this isn't a major concern, but the main reason it doesn't matter is that it doesn't matter. There are chemical poisons every bit as nasty as anything in a nuclear reactor which have a half-life of ~forever and aren't that hard to make or obtain. You can't prevent this because they're simple compounds made of common elements. People are afraid of nuclear because of its association with nuclear weapons, not because there is anything uniquely dangerous inside the reactor worse than things in chemical plants all over the place that nobody pays any attention to.
- lazide 3y ago
  Eh, kinda. The chemical ‘poison’ equivalent to a hot fuel rod (if spread around) is probably roughly equivalent to a couple hundred liters of VX nerve gas or Sarin.. Which, if not near anyone, isn’t very dangerous! It will lose that strength pretty quickly, and the longer lived elements are more like a ton of PCBs, or several tons of organic lead compounds. Not great, don’t live there, but with proper PPE it wouldn’t kill you anytime soon. But if moved to a place where people are at and can’t escape from, or smeared on something worth a lot of money, is a really big problem. If magnified (with say cobalt powder), it could be an even bigger mess. Hot fuel rods are very strictly controlled for a reason.
  - AnthonyMouse 3y ago
    It depends on what kind of damage you're trying to cause. Someone would use different chemicals for trying to kill a lot of people in one place immediately than trying to cause a large economic impact by filling the area with something expensive to eliminate that causes health problems. But the same is true of radioisotopes. The most immediately fatal ones have a short half-life and are only effective at that when concentrated rather than dispersed over a large area. If you have physical access to something with a high monetary value and you want to mess it up, chemical explosives do just fine and can be made from ordinary household substances. > Hot fuel rods are very strictly controlled for a reason. The main legitimate reason is that some existing reactors were purposely designed not to poison the fuel with heavier Plutonium isotopes in a way that makes it unsuitable for producing weapons, because the countries wanted to use them for that, but that can be solved in newer designs by doing the opposite. The main political reason is media fear mongering and decades of Russian propaganda designed to keep people buying Russian gas. Which you can kill as many people with as you can with a fuel rod, but half the population has it piped into their homes.
rich_sasha 3y ago
You can still put them on a small few sites, with heavy security. You will still reap the yet-to-be-demonstrated benefit of cheaper per-MW power (personally I'm hopeful).
WatchDog 3y ago
There are already hundreds(thousands?) of geographically distributed nuclear weapon silos. I would be more worried about weapons than I would be about nuclear waste.
- actionfromafar 3y ago
  Put an SMR next to every silo, then. The security is partly paid for already, I guess?
jillesvangurp 3y ago
It's a good thing to call out. The short version of this is that nuclear proponents are a bit hand wavy on this topic and that there is no good plan for this; nor any economical modeling worth talking about. But there's no such thing as nuclear power deployed on an insecure location. At best you have nuclear plants on very remote or hard to reach sites where the security is a bit minimal. But essentially all existing nuclear is the subject of intense and costly security. Under current non proliferation treaties, that's neither optional nor likely to change any time soon. Logically that means co-locating small nuclear plants on larger sites is the most cost effective way to secure them. That's something people have speculated about. The most suitable locations for that would be existing nuclear plants and decommissioned coal plants. Of course if you do that, you need to compare the efficiency of having lots of small reactors in one place and compare it to having 1 big reactor in the same place. Big reactors tend to be more efficient. The notion that you can just fedex these things to wherever, plop them down and then check back in 30 years is a bit naive. That's not how it works in the real world. People deploying these things are going to be on the spot for securing them at a non zero cost. 24x7 for life time of the reactor and the waste. Total cost of ownership is not limited to production and shipping (also needs security) but also has to include inspections, day to day operations, site security, waste disposal, handling, and security. (though that is commonly excluded and off-loaded on future generations of course), etc. If you exclude all those things the cost per kwh looks more rosy than it is. The real cost is something most nuclear proponents avoid talking about simply because it generally looks pretty bad. But somebody still has to pay for that.
goodpoint 3y ago
> How do you protect infrastructure with many SMRs? You don't. In times of increasing polarization and risks of social unrest we need safe and decentralized energy sources like PV.
sidewndr46 3y ago
I can't speak for the UK but in the US this can't be true. The plan for nuclear waste from the energy industry in the US is to leave political office before it is an issue. There is no way to dispose of it, period. Multiple plans have been put forth, many billions spent and none of it has ever actually been implemented. I think the military is a little different in that they get to override certain concerns.
belorn 3y ago
A Nuclear power plant as a target for terrorists sounds nice as a movie plot, but in practice it sound as a lot of work for much less results. If they wanted to go after the power infrastructure, a hydrpower dam are generally just guarded with fences and cameras, has built in weak points, and the destruction they bring causes whole nation to shut down. As a side effect they also bring down down stream transmission lines, shutdowns roads transportation on water, rail and road. A dam is basically a large number of nuclear bombs suspended above all the city that is down stream. Going down in scale, natural gas deliveries, especially train and trucks, are rolling bombs. 22 tank cars has the equivalent energy of the Hiroshima bomb. Both trains and trucks goes through city centers. Those things are dangerous even without terrorist plots. Laws against this however has generally gone the other direction, with more freedom for train and trucks to transport this with less security.

BlueTemplar 3y ago

I am more concerned about when/if we have millions of small nuclear reactors around, some of them will end up abandoned/lost. Then many years later, they will start to leak (think rain getting in).

samus 3y ago
Unlikely, that would imply a major breakdown of civilization. They are all connected to power lines, else they would not have been installed in the first place.
- BlueTemplar 3y ago
  Well yes, major breakdowns of civilization have happened before and will happen again. There's one going on right now on the Ukraine/Russia border !
  - samus 3y ago
    And we saw what happens when nuclear installations are caught behind frontlines. In such situations, installations composed of SMRs would have advantages. For example, artillery blowing one up would be quite gnarly still, but less so than if that happened to a much larger monolithic plant!
- gambiting 3y ago
  I mean during cold war many RTGs were deployed in remote regions of the world and subsequently lost. We even know of some cases where random people came across them and opened them up(unknowingly killing themselves in the process).
  - samus 3y ago
    SMR won't deployed to remote locations and then forgotten though. They will be installed and managed like usual nuclear installations: at dedicated sites, with appropriate security, and close supervision. Their purpose is to make these installations more modular and thus cheaper to maintain, extend, upgrade, and ultimately to decommission.
    - BlueTemplar 3y ago
      And yet before this I kept seeing publications about how they can be packed in a few containers/trailers and delivered anywhere to start producing heat/power... I guess it might have been about a different company, but you can understand my worries ? Also comes to mind the previous recklessness of some : while the USA has judged the use of "full blown" nuclear reactors in space too dangerous, the USSR launched 33 of them, 3 of which accidentally fell back to Earth, one contaminating a chunk of Canada. They even seemed to have kept launching them after Chernobyl, though that might have been inertia ? https://en.wikipedia.org/wiki/US-A https://en.wikipedia.org/wiki/US-A
      - samus 3y ago
        Just because it could be deployed almost anywhere, doesn't mean it will. Just like with rental housing containers that could be ordered to be shipped anywhere a road leads to. We will likely see more nuclear installations though due to the fact that they don't have to be gargantuan to scale with the engineering costs. But they will be subject to the same regulatory regime that governs the existing installations.

naasking 3y ago

Switch to a thorium fuel cycle so virtually all of the fissionable material is spent, rather than 90+% of it remaining in the waste.

perlgeek 3y ago
Somehow, Thorium has been the future of nuclear reactors about as long as fusion has been. It's almost a running gag. (And yes, I know that there are concrete plans for commercial Thorium fission reactors, in a way that aren't for fusion, but still no fully-operating, commercial reactor, afaict).
- AnthonyMouse 3y ago
  That's not really saying much given the number of new nuclear reactors of any fuel source the west has built in the current century. You have to build something in order to build something that runs on Thorium.
LorenPechtel 3y ago
Just use breeder reactors. Somebody repurposing the plutonium? No. Plutonium is not plutonium. For a bomb you need Pu-239. The more Pu-240 in your material the harder it is to slam the pieces together fast enough to avoid a premature chain reaction from robbing your bomb of most of it's power. For both bomb-making and fuel breeding the desired reaction is U-238 + n => U-239, decays to Np-239, decays to Pu-239. There is also the reaction Pu-239 + n => Pu-240. The power guys don't care, Pu-240 works fine. The bomb guys do care. Thus the power guys leave the fuel in the reactor until too much neutron poison builds up. The bomb guys leave the fuel in the reactor only a short time.

gadders 3y ago

Hire more of these people? https://www.gov.uk/government/organisations/civil-nuclear-constabulary/about https://www.gov.uk/government/organisations/civil-nuclear-co... "The Civil Nuclear Constabulary (CNC) is the armed police force in charge of protecting civil nuclear sites and nuclear materials in England and Scotland."

credit_guy 3y ago

> Every nuclear power plant is a fantastic target for terrorists. It is not. Let's say you are a terrorist, and you and your team have taken hold of a nuclear power plant. Then what? It's a problem for the world, but not different from you taking over a hotel or a city hall. You might threaten or even kill hostages, but there's no way you can create a significant nuclear threat. Let's say you force an operator, at gunpoint, to remove some rods from the reactor, or otherwise you get possession of some nuclear material. So what? How are you going to get away? You will be surrounded by hundreds or thousands of SWAT officers. What is the scenario where it will make a difference if they take over the nuclear power plant vs a different building?

naasking 3y ago
The point is that they could potentially abscond with nuclear material before being surrounded, obviously.
- inglor_cz 3y ago
  Handling nuclear material straight out of the reactor is a good way to kill yourself very painfully.
  - naasking 3y ago
    Sure, but if we're talking about terrorists that a documented history of being willing to blow themselves up, I don't see why they wouldn't do this too. To avoid the painful death, blow yourself up after absconding but before radiation poisoning really takes its toll.
    - throwway120385 3y ago
      We're talking about people with EG civil engineering degrees masterminding these plots. The middle-eastern terrorists of yesteryear are not necessarily uneducated. Osama Bin Laden was educated as an engineer in the US and likely would have thought through the endgame and implications of such a plot well before executing it. These people are not stupid and would likely know what they are getting in to. I'd be more worried about a single unhinged person, but that's why we have security guards, and the problem would likely solve itself in short order in that case.

3D30497420 3y ago

My issue with thinking like this is that there are plenty of targets for terrorists: packed trains, stealing a big truck, etc. The fact that these events are pretty rare suggests that there aren't nearly as many terrorists as people seem to be worried about. Every power generation method has its plusses and negatives. I don't know if the risk from an SMR incident outweighs other methods, but it sounds promising. We certainly need an alternative to sources we know are bad (coal, oil, etc).

psunavy03 3y ago
Western society in general is a bunch of future cancer and heart disease victims all freaking out that they're going to die in a nuclear meltdown, or by the hand of a terrorist, or by a lone gunman "mass shooter," or in a plane crash, or any number of other threats that are scary but statistically highly unlikely. Human beings are just utter crap at intuitively estimating risk.
- throw0101c 3y ago
  > Western society in general is a bunch of future cancer and heart disease victims all freaking out that they're going to die in a nuclear meltdown […] Also, COVID (to round out the top three in many places).
  - appointment 3y ago
    COVID has killed 7 million people since 2019. Airliner* crashes killed 80 people in 2023. These risks are not of the same class. * admittedly I'm exaggerating slightly by not considering private and military aviation, but I'm too lazy to find that total.
    - sidewndr46 3y ago
      The difference is you can trivially avoid death by airliner crash. You can't practically reduce your chance of death by COVID unless you simply never go outdoors or have visitors

chasil 3y ago

Ideally, the reactor is designed in such a way that a catastrophic failure is not possible. Something along the lines of the salt plug in a molten salt reactor, that melts when cooling fails and dumps the liquid into a boron bath, halting fission.

areoform 3y ago

Getting to the material is mechanically difficult. It's also the type of problem that neatly solves itself. A fuel rod toting terrorist is a dead terrorist. > The acceptance criteria in DSRS Section 12.3–12.4 state that accessible portions of the facility that are capable of having radiation levels greater than 1 Gy/h (100 rads/h) should be shielded and clearly marked with a sign stating that potentially lethal radiation fields are possible. DCA Part 2, Tier 2, Revision 3, identifies a number of areas (e.g., resin demineralizers, filters, SRSTs) that may contain quantities of radioactive material resulting in radiation dose rates exceeding 100 rads/h (1 Gy/h). Now what I'm about to say changes with the fuel being used, but from LLNL's report, > Even for fuel that has cooled for 15 years, a lethal dose (LD50) of 450 rem can be received at 1m from the fuel assembly after several minutes. https://www.osti.gov/servlets/purl/10137382 https://www.osti.gov/servlets/purl/10137382 Good luck trying to carry that stuff out. They'll be the walking dead in a few minutes. They'll be unable to walk and will be just dead in ~100 minutes. Give or take 10 to 20 minutes depending on how they're holding the item etc. https://en.wikipedia.org/wiki/Acute_radiation_syndrome#Dose_effects https://en.wikipedia.org/wiki/Acute_radiation_syndrome#Dose_... And no, they can't just "put it in [a] lead [box]" to run away with it, because then they'll die to bremsstrahlung radiation or braking radiation. It'll take longer, but the end result will be the same. If it's fuel that hasn't gone into the reactor yet/hasn't undergone neutron activation, then it's not radioactive enough to be a concern unless consumed. Terrorists are rare and they're usually not that capable. It's easier for them to buy a gun or a lorry and mow down a crowd than it is to plan a fiendishly complicated radiation heist.

giva 3y ago
I just want to point out that a terrorist that drives a plane into a skyscraper is a dead terrorist too. You need one terrorist to extract the material and put some quantities in a somewhat shielded container before being incapacitated, and then others to spread it on the subway.
- areoform 3y ago
  Radiation isn't magic. Several feet/meters of water are used as shielding for the fuel for a good reason. If you put an activated fuel rod inside of a lead lunch box, you will still die. You will now die from a lethal dose of bremsstrahlung. https://en.wikipedia.org/wiki/Bremsstrahlung https://en.wikipedia.org/wiki/Bremsstrahlung If you interact with this material as an amateur without processes, robotics and safety, you will die. Period. You will also suffer from intense nausea and be unable to move before you die. Sharks with lasers are more realistic than this concern. The more plausible scenario is a "dirty bomb" that spreads depleted uranium particles everywhere and gives people cancer long-term. But there's an element of impracticality to this and there's a reason why it hasn't happened yet.

mytailorisrich 3y ago

I expect SMRs would be protected as standard nuclear plants are. Therefore, these are not easy targets and we've seen that they are very easy targets everywhere that will have the desired effect.

ElectronCharge 3y ago

I like the idea of siting them underground, which completely addresses the aircraft strike vulnerability. Physical security is also easy when they're underground. Thorcon was pursuing this, but has switched to a ship-based approach. Searching today, I found a new (to me at least) company that's working on a truly small reactor, 3-15 MW electricity, and is planning on underground siting: https://www.usnc.com/mmr/ https://www.usnc.com/mmr/ It also supplies 10-45 MW of thermal, so great for poleward climes. Fission will be a critical technology going forward, until fusion generation can compete on power to size/weight ratio...and cost. And until aneutronic fusion power is practical, there's no large benefit to fusion regarding waste.

jszymborski 3y ago

SMRs feel like a much worse target from what I understand. I'm no expert, but my understanding 1) SMRs are typically designed to be walk-away safe. Their smaller capacity means its harder for them to go critical in a spectacular way. [0] 2) Distributed targets are hard to respond to, but they're also hard to hit in an impactful way. Instead of having to hit one giant nuclear plant which supplies an entire regions energy, you have to hit many much smaller targets which supply much less energy. [0] https://www.forbes.com/sites/jamesconca/2018/01/24/can-we-make-a-nuclear-reactor-that-wont-melt-down/ https://www.forbes.com/sites/jamesconca/2018/01/24/can-we-ma...

Retric 3y ago
Getting it critical is a long way from the worst thing you can do with access to one or more SMR. However, nobody is going to be using these things individually. You still need a steam turbine, and cooling tower etc. So the general assumption is people will be using 10+ of these things and the added complexity would be offset by economies of scale.

AnthonyMouse 3y ago

> The one thing I still wonder is whether SMRs could create a security nightmare. People are going to tell you why this isn't a major concern, but the main reason it doesn't matter is that it doesn't matter. There are chemical poisons every bit as nasty as anything in a nuclear reactor which have a half-life of ~forever and aren't that hard to make or obtain. You can't prevent this because they're simple compounds made of common elements. People are afraid of nuclear because of its association with nuclear weapons, not because there is anything uniquely dangerous inside the reactor worse than things in chemical plants all over the place that nobody pays any attention to.

lazide 3y ago
Eh, kinda. The chemical ‘poison’ equivalent to a hot fuel rod (if spread around) is probably roughly equivalent to a couple hundred liters of VX nerve gas or Sarin.. Which, if not near anyone, isn’t very dangerous! It will lose that strength pretty quickly, and the longer lived elements are more like a ton of PCBs, or several tons of organic lead compounds. Not great, don’t live there, but with proper PPE it wouldn’t kill you anytime soon. But if moved to a place where people are at and can’t escape from, or smeared on something worth a lot of money, is a really big problem. If magnified (with say cobalt powder), it could be an even bigger mess. Hot fuel rods are very strictly controlled for a reason.
- AnthonyMouse 3y ago
  It depends on what kind of damage you're trying to cause. Someone would use different chemicals for trying to kill a lot of people in one place immediately than trying to cause a large economic impact by filling the area with something expensive to eliminate that causes health problems. But the same is true of radioisotopes. The most immediately fatal ones have a short half-life and are only effective at that when concentrated rather than dispersed over a large area. If you have physical access to something with a high monetary value and you want to mess it up, chemical explosives do just fine and can be made from ordinary household substances. > Hot fuel rods are very strictly controlled for a reason. The main legitimate reason is that some existing reactors were purposely designed not to poison the fuel with heavier Plutonium isotopes in a way that makes it unsuitable for producing weapons, because the countries wanted to use them for that, but that can be solved in newer designs by doing the opposite. The main political reason is media fear mongering and decades of Russian propaganda designed to keep people buying Russian gas. Which you can kill as many people with as you can with a fuel rod, but half the population has it piped into their homes.

rich_sasha 3y ago

You can still put them on a small few sites, with heavy security. You will still reap the yet-to-be-demonstrated benefit of cheaper per-MW power (personally I'm hopeful).

WatchDog 3y ago

There are already hundreds(thousands?) of geographically distributed nuclear weapon silos. I would be more worried about weapons than I would be about nuclear waste.

actionfromafar 3y ago
Put an SMR next to every silo, then. The security is partly paid for already, I guess?

jillesvangurp 3y ago

It's a good thing to call out. The short version of this is that nuclear proponents are a bit hand wavy on this topic and that there is no good plan for this; nor any economical modeling worth talking about. But there's no such thing as nuclear power deployed on an insecure location. At best you have nuclear plants on very remote or hard to reach sites where the security is a bit minimal. But essentially all existing nuclear is the subject of intense and costly security. Under current non proliferation treaties, that's neither optional nor likely to change any time soon. Logically that means co-locating small nuclear plants on larger sites is the most cost effective way to secure them. That's something people have speculated about. The most suitable locations for that would be existing nuclear plants and decommissioned coal plants. Of course if you do that, you need to compare the efficiency of having lots of small reactors in one place and compare it to having 1 big reactor in the same place. Big reactors tend to be more efficient. The notion that you can just fedex these things to wherever, plop them down and then check back in 30 years is a bit naive. That's not how it works in the real world. People deploying these things are going to be on the spot for securing them at a non zero cost. 24x7 for life time of the reactor and the waste. Total cost of ownership is not limited to production and shipping (also needs security) but also has to include inspections, day to day operations, site security, waste disposal, handling, and security. (though that is commonly excluded and off-loaded on future generations of course), etc. If you exclude all those things the cost per kwh looks more rosy than it is. The real cost is something most nuclear proponents avoid talking about simply because it generally looks pretty bad. But somebody still has to pay for that.

goodpoint 3y ago

> How do you protect infrastructure with many SMRs? You don't. In times of increasing polarization and risks of social unrest we need safe and decentralized energy sources like PV.

sidewndr46 3y ago

I can't speak for the UK but in the US this can't be true. The plan for nuclear waste from the energy industry in the US is to leave political office before it is an issue. There is no way to dispose of it, period. Multiple plans have been put forth, many billions spent and none of it has ever actually been implemented. I think the military is a little different in that they get to override certain concerns.

belorn 3y ago

A Nuclear power plant as a target for terrorists sounds nice as a movie plot, but in practice it sound as a lot of work for much less results. If they wanted to go after the power infrastructure, a hydrpower dam are generally just guarded with fences and cameras, has built in weak points, and the destruction they bring causes whole nation to shut down. As a side effect they also bring down down stream transmission lines, shutdowns roads transportation on water, rail and road. A dam is basically a large number of nuclear bombs suspended above all the city that is down stream. Going down in scale, natural gas deliveries, especially train and trucks, are rolling bombs. 22 tank cars has the equivalent energy of the Hiroshima bomb. Both trains and trucks goes through city centers. Those things are dangerous even without terrorist plots. Laws against this however has generally gone the other direction, with more freedom for train and trucks to transport this with less security.