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."
(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).
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.
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?
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.
But it is well possible that some people could still try. The Four Lions, only in the real world.
The other stuff sure, but it takes a truly mind boggling amount of radiation to incapacitate someone (near) instantly. A lot more than that.
100-150 Gy? The only concrete number I found looking around for ‘instant’ was 1000 Gy to likely kill someone within an hour.
I think incapacitation is what matters. The human body will fight death for some time, but it won't be able to running around with a heavy backpack of fission material. Various tissues will scream bloody hell almost immediately from being torn apart by the radiation.
Definitely a death sentence either way.
It's a fascinating(if very morbid) read if you want to have a look:
https://www-pub.iaea.org/MTCD/publications/PDF/Pub925_web.pd...
The point is, that maybe the terrorists wouldn't be inacapacitated, but they certainly wouldn't be able to ignore the effects for very long if at all.
https://www-pub.iaea.org/MTCD/publications/PDF/Pub925_web.pd...
> In the United States, the design and thickness of the containment and the missile shield are governed by federal regulations (10 CFR 50.55a), and must be strong enough to withstand the impact of a fully loaded passenger airliner without rupture.
What if they just want to overide the safety mechanisms of the reactor and trigger a meltdown?
This is why the crackdown on modern terrorism became so draconion.
They love death as we love life.
Well, actually we don't know this for sure, because the guy (obviously) did not survive to tell the story. It may have been intentional suicide, or simply an unintentional operator error.
But it does not matter. Since then the design of nuclear reactors evolved in such a way as to make it very difficult for an operator to be able to intentionally or unintentionally trigger a blow-up or a melt-down.
It’s good to hear that it’s risk that is already mitigated.
Personally the thing that turns me off nuclear the most is that if things do go wrong sections of land basically become uninhabitable for thousands of years. I probably shouldn’t care but it seams like a major downside.
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).
Human beings are just utter crap at intuitively estimating risk.
Also, COVID (to round out the top three in many places).
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.
[https://en.wikipedia.org/wiki/Nuclear_fallout]
For actual studies on the impacts, see [https://pubmed.ncbi.nlm.nih.gov/11109179/]
Notably, Stronium-90 levels in deciduous teeth of kids born in the 80's.
"Strontium-90 concentrations in deciduous (baby) teeth of 515 children born mainly after the end of worldwide atmospheric nuclear bomb tests in 1980 are found to equal the concentrations in children born during atmospheric tests in the late 1950s. Recent Sr-90 concentrations in the New York-New Jersey-Long Island metropolitan area have exceeded the expected downward trend seen in both baby teeth and adult bone after the 1963 ban on atmospheric testing. Sharp rises and declines are also seen in Miami, Florida. In Suffolk County, Long Island, Sr-90 concentrations in baby teeth were significantly correlated with cancer incidence for children 0 to 4 years of age. "
Stronium in teeth is a proxy for Stronium in bones too, and those don't fall out.
> Human beings are just utter crap at intuitively estimating risk.
It's like worrying about the KGB covertly planting listening devices in your house while tech companies are openly planting listening devices in your house. It's not at all unreasonable to be concerned about invasion of privacy, but the people who think they're at significant risk of being individually targeted by the security service of the former Soviet Union because of what they saw on TV have got a screw loose.
The people who prioritise 0-risk living over energy security are self defeating; but the problem is they keep trying to take the rest of us down with them. Their victory of nuclear energy might technically be one of the biggest catastrophes to ever hit humanity. We have never been hit by something else with so high an opportunity cost in absolute terms. Blind and ignorant fear is no basis for making policy decisions.
Defaulting to extreme skepticism and caution towards any technology that dangerous is not a bad starting point though.
For the fuckwits in any given electorate, your maxim would be better phrased as "default to not having any fucking opinion at all on that of which you know not"
The counterargument is that blowing up a train or stealing a truck usually doesn't poison the local area for generations. Higher risks means some consideration is due. If the stakes are higher but the probability is the same, the expected value is still higher.
I for one don't want to live in a hellscape pockmarked by miniature exclusion zones.
The market has spoken on that matter.
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.
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).
> 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.
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_...
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.
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.
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
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.
https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident
https://en.wikipedia.org/wiki/Kramatorsk_radiological_accide...
These incidents, while uncomfortable, are just not that concerning. You can kill yourself with damn near anything if you mishandle it badly enough.
[0] https://en.wikipedia.org/wiki/Solanine#Recorded_human_poison...
Until they did it.
After all, it’s very impractical getting a bunch of random terrorists training in flying well enough to do this without being caught.
Let alone co-ordinating everything, getting through multiple layers of airport security, etc.
And everyone ‘successful’ is going to die too. Who would do that?
Historically, terrorists would just hijack a plane for attention and/or money and then let everyone go except for those stupid enough to fight them.
Which is why the reaction onboard to the terrorists taking the planes was so muted, until a passenger on one of the planes heard the news of the first impact, and they realized they were in a very different situation than a hijacking for money.
Not considering dirty bomb type issues a threat would likely be a mistake.
Having a bunch of disposable idiots throw hot fuel rods into a water tanker truck, then driving to manhattan, seeding the water with cobalt-59, and letting the mess ‘sort itself out’ (or blowing the the truck up) certainly wouldn’t be hard compared to 9/11 in these scenarios, or likely kill more than a handful of terrorists. Depending on how well secured the fuel was anyway.
It would create an absolutely terrific mess though.
The only hard part here would be getting the hot fuel (and the idiots), everything else would be ‘COTS’.
Which, like 9/11, would not be seen as ‘expensive’.
This isn’t sharks with lasers territory.
the real economics low-hanging fruit is to build those regular NPPs in increments, basically cheaper AND faster (which also means even cheaper). get real economies of scale, apply all of the last century's industrialization benefits on nuclear energy. (because current cost overruns are insane and mostly because of too-slow AND super-duper-artisanal (which means even slower) plant construction.
Was literally an episode of the Lone Gunmen. https://en.wikipedia.org/wiki/The_Lone_Gunmen_(TV_series)
In the pilot episode, which aired March 4, 2001 (exactly six months and one week prior to the September 11 attacks[5]), rogue members of the U.S. government remotely hijack an airliner flying to Boston, planning to crash it into the World Trade Center, and let anti-American terrorist groups take credit, to gain support for a profitable new war following the Cold War. The heroes ultimately override the controls, foiling the plot.Clearly, Vince Gilligan is a member of the illuminati. Though the list of follow up episodes was a bit meh. Perhaps also telling?
[https://en.wikipedia.org/wiki/The_Lone_Gunmen_(TV_series)#ci...], such as
Episode 6 - "A man contacts the Lone Gunmen, believing his life has been stolen after being abducted by aliens. They end up getting caught in a love triangle involving a one-eyed stereo salesman, brainwashing, and a wrestling dwarf."
Episode 10 - "Yves and Frohike go undercover as tango dancers to stop a man from selling government secrets."
Or, the real 'telling the truth in the form of a lie'?
Their last episode #13 - "The Lone Gunmen team up with Man in Black agent Morris Fletcher to find Yves. What they uncover is Romeo-61, a secret government organization responsible for decades of major incidents."
Was Vince picking up top-secret communications in his fillings (maybe even subconsciously) and ended up telling too much? Or a SG-1 style 'early disclosure'/'disinfo' campaign? Or false-false flag? Or coincidence? Or reaction to some actual gov't preparatory 'conspiracy theory' poisoning the well?
The world may never know. /s
Therefore, these are not easy targets and we've seen that they are very easy targets everywhere that will have the desired effect.
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/
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.
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-ma...
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.
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.
There is this kind of weird thing that people do where they assume nuclear waste is uniquely dangerous. It isn't! We can just measure it, so the danger is perfectly legible. This is a good thing! The rest of industrial waste is NOT like this. You can see studies of people who live in areas near oil refineries and chemical plants in Texas and Louisiana -- population level cancer and birth defect rates are very high. It's exactly as you say, bog standard "dangerous chemicals" are just as dangerous as nuclear radiation is. Only we can't measure them, so I guess what can ya do if a whole city gets birth defects or cancer?
The double standard is actually wild. I would prefer to live next to a nuclear plant, thank you very much. I can get a geiger counter and know if I'm being poisoned.
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.
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.
The issue is chemicals tend to be less dense and energy intense. And instill a lot less fear (usually). Many are heavily regulated too though, and some are getting more and more so.
For instance, can you name a chemical that will be any MORE expensive to clean off something you want to keep than a mixed radionucleotide soup? Even HF or FOOF should be way easier. Maybe methyl mercury?
Especially since (as Castle Bravo demonstrated), some of this stuff is essentially impossible to remove due to how chemically reactive it is. Some of the soup is going to want to bond like glue to everything, and is also pretty hot too - but not hot enough to be gone in a year or two.
To your point, there are definitely chemicals that can cause more actual immediate physical harm (probably), like phosgene. Or methyl mercury. Or a number of easily synthesizable chemical explosives.
But I'm not sure they would cause less fear than exploding a bunch of mixed 'hot' radionuclides in a crowded area. Probably because it wouldn't be predictable or immediately obvious who and how many would die. And there would be some pretty nasty looking video/photos of those who did.
To my original point - none of these are Sharks with Lasers on their head improbable, either way. And if someone wanted to instill as much fear and uncertainty as possible (like a terrorist), using the scariest method to the public as possible is going to be on their list.
So, worth making sure there are decent security precautions that actually get monitored/enforced, so someone doesn't just walk off with some hot rods at some point and cause a huge mess.
You won't find me arguing about propaganda and ideology though. Near as I can tell, that's killed more humans than anything else - and will continue to do so.
Also worth burning various media offices to the ground probably, but good luck getting any group of people to agree on whose eh?
Eh. Nuclear reactors are expensive because of regulatory requirements, not physics. It's not that hard to get natural uranium. If you're a criminal who just wants fission byproducts and doesn't care about NRC approval, you could make one without too much trouble. If you had some basic knowledge you might not even kill yourself.
> For instance, can you name a chemical that will be any MORE expensive to clean off something you want to keep than a mixed radionucleotide soup? Even HF or FOOF should be way easier.
HF or FOOF might not be that easy to remove now that the thing you're trying to clean it off of has been dissolved by acid or vaporized in the resulting explosion. It is in general hard to clean something after it has ceased to exist.
> But I'm not sure they would cause less fear than exploding a bunch of mixed 'hot' radionuclides in a crowded area.
I hate to quote FDR so maybe we should use the example of the English during The Troubles.
If you allow yourself to be terrorized, you let the terrorists win. People are afraid because the media and politicians tell them to be afraid because they're manipulating you just as much as the terrorists are, for their own purposes. Anyone caught doing this should be regarded as committing an act of betrayal and condemned as a coward attempting to capitalize on a tragedy.
> Also worth burning various media offices to the ground probably, but good luck getting any group of people to agree on whose eh?
You don't actually have to burn down their offices. Just stop watching them and at scale they'll fail.
And then you're more visible/have more of a footprint, and it's a lot harder to get under the radar.
And perhaps you'd even have something more useful to do with your life - or at least you'd have something you'd be hesitant to lose in retaliation.
Same as if you're able to build your own airplanes, you don't need to hijack any. But also, if you can hijack an airplane to do what you want to do - why bother going to the effort of building your own?
And as for the other points - I've never been worried about Hamas or personally cared to watch Fox News - and it's been decades. I also stopped reading/watching any general news several years ago.
So why are they not only still there, but have caused a lot of damage since? And made a lot of money?
No man is an island. And no matter how mentally healthy someone in Stalingrad was, they were still in for a world of hurt between '42 and the '60's, eh?
And if you refuse to use a tool against someone who will not hesitate to use it against you, guess what tool they'll eventually end up using all the time?
Gosh no. Rocket science is legitimately hard to the point that it's a cliche. Getting some elements to do physics together when you don't care about regulatory requirements is pretty much just a matter of putting them near each other and hoping you used enough shielding that it won't kill you.
> So why are they not only still there, but have caused a lot of damage since? And made a lot of money?
Because other people watched them, of course. Everyone has to do their part by turning off the fear-mongering talking heads. You can't stop other people from doing it, but you can stop doing it yourself, and so could they.
> And if you refuse to use a tool against someone who will not hesitate to use it against you, guess what tool they'll eventually end up using all the time?
The one that makes everyone hate them.
It is not possible to defeat evil by doing evil. You only become that which is to be defeated.
And the Nazi’s were destroyed by…. Hugs?
And not firebombing, machine gunning, etc. most of Western Europe?
Let me know when you care about reality more than the illusion.
Some things, it's an existential threat - and existential threats like that tend to only be resolvable with by death or complete subjugation of one side or the other.
Notice how we were talking about terrorists and you had to switch to WWII to actually find an existential threat, and yet once you normalize these measures they become routine. Even the term "national security" was meant to imply this -- something critical to the security of the nation, that could cause it to fall to an enemy. How is this applicable to the War on Terror? Was the United States ever at risk of surrendering to bin Laden and disbanding Congress in favor of a Caliphate? It was not, and yet "national security" was the justification for every evil act committed in the name of fighting evil.
If you're weaker than someone else and you can win without fighting dirty, you're clever. If you're stronger than someone else and you can't win without fighting dirty, you deserve to lose.
Bin Laden initiated 9/11 on his own, destroyed a huge center piece of the US financial system and terrorized the entire country.
Were the responses justified, or useful?
What does that have to do with my point that hugs solve none of these actual real world problems?
Do you think that if the US had gone ‘oh, sorry yeah you have a point - our bad’ that things would have worked out better?
And I don’t see how that has anything to do with the risk that someone might also make a dirty bomb - you know, the conversation we’ve actually been having?
Until you actually talk about something related to real world situations here instead of constantly dodging them, I’m out.
> Some things, it's an existential threat - and existential threats like that tend to only be resolvable with by death or complete subjugation of one side or the other.
But a dirty bomb is not an existential threat to the United States. The US military actually evaluated them for their own use and concluded that they're militarily useless and not worth developing.
And since we're not dealing with an existential threat, we don't have to do anything radical to address it. Did some terrorists do a terrorism? Arrest them. They can't keep doing terror plots when they're locked up in prison forever, and if the result of terrorism is "you go to prison and nothing else changes" then there isn't a lot of incentive for anybody to do it.
Of course a dirty bomb isn't militarily useful to the US gov't. They have literal nuclear weapons. Hijacking a civilian airliner and using it to attack a target in a suicide attack ALSO isn't militarily useful to the US government. They have cruise missiles.
They also wouldn't stoop to these kinds of tactics, and have overpowering force in other areas, so what else is the enemy going to use (eventually)?
A tiny group (equivalent to a US Army Company in size) being able to attack one of the most prominent financial centers of the United States successfully (and, notably, the Pentagon as well!) on live TV, instilling fear and terror in the populace, and even getting away with it for a decade is of course an existential threat to the United States.
Near as I can tell, no country in the world could pull that off successfully, not even Russia or China.
And how do you propose the gov't was going to 'just arrest' Osama Bin Laden? Or any other terrorist group?
The whole point is that they hide among civilians and go deep underground when hunted, using what we won't do to be successful.
It took a decade to even FIND OBL. And if they put him on trial, it would just give him an audience to push buttons and get his message out even wider and stir up more shit. Look at what is going on with Israel and Palestine/Hamas.
And how would you propose that the gov't not have the populace scared when something like 9/11 happens.
Should the news just not report on someone plowing nearly fully occupied airliners into the iconic and fully occupied World Trade Center towers in downtown Manhattan, or the Pentagon - in broad daylight during a workday, no less.
Towers that were common tourist hotspots and were plainly visible literally from some of the busiest streets in one of the most prominent cities in the entire world?
With no warning, and no effective countermeasures or prevention at the time?
Or that the entire US picks up deep meditation practice to understand the futility of 'holding on' to such things and how they get used against oneself?
Neither of those are realistic, or even a good idea near as I can tell in this situation.
Honestly, this type of attitude is exactly what leads up to these kinds of situations happening. It's sticking one's head in the sand.
And the world isn't slowing down. Check out this 3D printed surface to air missile project on Youtube.
[https://www.youtube.com/watch?v=UvcDwSmmxWs]
And this little piece on the Glock Switch, which has been circulating for years. Also easy to make at home with a 3D printer, a vise, and a file.
[https://www.youtube.com/watch?v=DfVKcItEaiE]
I'm done wasting my time in this discussion now.
I would be more worried about weapons than I would be about nuclear waste.
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 ?
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.
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.
You don't. In times of increasing polarization and risks of social unrest we need safe and decentralized energy sources like PV.
I think the military is a little different in that they get to override certain concerns.
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.
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?