11 ms·

> I'm not keen on new nuclear (time and cost as much as anything else), but it's a terrible idea to phase out operating nuclear plants which are still safe and

> I'm not keen on new nuclear (time and cost as much as anything else), but it's a terrible idea to phase out operating nuclear plants which are still safe and within their planned lifetime. Funnily, I have almost the opposite view. I'm terrified of old nuclear because those first gen power plants are all missing a lot of safety lessons. Nuclear disasters happen at old plants. I want old nuclear plants to be either upgraded or decommissioned. I have much less concern about new nuclear (other than it taking a very long time and an a lot of money to deploy). A healthy social attitude to nuclear would be to require periodic upgrades or decommissions as the plant ages.

thrownthatway 6mo ago
What nuclear disasters? Exactly? Name one nuclear disaster at an old nuclear plant whose lessons weren’t applied to the whole fleet.
- cogman10 6mo ago
  Fukushima. It was a Gen 1 plant which already has the issue that a thermal runaway is possible. There were other examples of this happening like TMI. The backup for Fukushima was onsite generators which were flooded and ultimately failed causing the meltdown. The safety lessons we learned from all gen 1 reactors was to apply passive shutdown mechanism where if input power fails fission ultimately stops. That's not something that can be applied across the fleet because it requires more infrastructure and an almost complete redesign of the reactor's setup. Which is why these early reactors all have a potential risk of thermal runaway. Edit: It looks like all gen Is have been decommissioned as of 2015, which is great. But we really should now be talking about decommissioning gen IIs and leaping forward to Gen IVs.
  - navane 6mo ago
    That's a big nevertheless.
  - leonidasrup 6mo ago
    Fukushima Daiichi Nuclear Power Plant was NOT using Generation I reactors. "Gen I refers to the prototype and power reactors that launched civil nuclear power. This generation consists of early prototype reactors from the 1950s and 1960s, such as Shippingport (1957–1982) in Pennsylvania, Dresden-1 (1960–1978) in Illinois, and Calder Hall-1 (1956–2003) in the United Kingdom. This kind of reactor typically ran at power levels that were “proof-of-concept.”" https://www.amacad.org/publication/nuclear-reactors-generation-generation/section/5 https://www.amacad.org/publication/nuclear-reactors-generati...
    - cogman10 6mo ago
      Got my gens mixed up, so thanks. But I think my point is still valid. These Gen II reactors should be retired and replaced.
  - shawabawa3 6mo ago
    It's worth noting that the Fukoshima disaster 1. Lead to basically zero direct deaths 2. Was caused by the forth most powerful earthquake to have ever been recorded in the world (since ~1900), and the most powerful earthquake ever recorded in Japan 3. ~20,000 people died due to the Earthquake Requiring a nuclear plant in Belgium to be safe enough to survive what caused the Fukoshima disaster is probably not a good use of money
    - wholinator2 6mo ago
      I don't know but i feel like Nuclear reactors are something worth taking to the 99.99% percentile of safety. How much money does it really cost? And how does that money compare to the economic prosperity of the land that is currently radiation free. As well, i think us (assuming) not knowledgeable Nuclear engineers discussing the cost benefit of reactor safety should be basically locked out of the conversation. Plausible sounding soundbites are just too easily generated these days for anyone without credentials to have stake in these decisions.
      - swiftcoder 6mo ago
        > How much money does it really cost? The problem is as much time as it is money. We have reactors producing energy now, it will take a decade plus to replace them, and due to both climate policy and supply issues around the wars in Russia and the Middle East, we can't afford to do without the energy for that decade...
        simondotau 6mo ago
        And if that nuclear would be displacing coal power, you have to consider the health and environmental costs of that coal generation which you haven't displaced.
        thrownthatway 6mo ago
        > climate policy Fuck climate policy. There could be an earthquake any moment now that ruptures a massive natural CO formation that would eclipse any anthropogenic generated emissions in matter of hours. What have we done to mitigate that risk? Nothing. There is a non-zero chance Earth will be relieved of the responsibility of harbouring complex life any moment now by a loose pile of gravel travelling at 60 kilometres a second. Zero mitigation. Let’s work out this food-housing-energy deal for everyone before we mandate unaffordable unreliable energy that results in unaffordable everything. Maybe your shielded from that because your own a mid six figure income at $UNICORN, but I guarantee you the rest of us have had enough of this climate change fucking bullshit luxury belief.
  - SoftTalker 6mo ago
    > if input power fails fission ultimately stops AIUI fission was stopped basically immediately. The problem was removing the decay heat from the fission by-products; without pumps to move cooling water that didn't happen. I think modern reactor designs have enough passive cooling that this failure mode can't happen. There are a lot of active reactor plants where it still could be possible though.
  - thrownthatway 6mo ago
    Fukushima Daiichi is irrelevant to European nuclear reactor safety.
  - deleted 6mo ago
    [deleted]
- mannykannot 6mo ago
  The claim that disasters happen to older plants is not refuted by the observation that lessons learned are applied to the whole fleet. One might object that there is selection bias in the original claim, due to the slowdown in construction of recent plants, but that is a separate issue. A more thorough investigation of the causes of all events leading to a significant degradation of safety margins would be needed to determine whether and how older designs are inherently more risky and whether that risk can be adequately mitigated given the constraints imposed by their design. The fact that, prior to Chernobyl, there were several foreshadowing incidents with RBMKs which should have raised serious concerns, suggests that 'lessons learned' isn't much of a reason to be satisfied with the status quo.
  - thrownthatway 6mo ago
    RMBKs are irrelevant to nuclear reactor safety. You had a good argument up until you went there.
    - anonymars 6mo ago
      Even if we don't treat Chernobyl as sui generis, the safety situation with nuclear power is akin to that of airplanes. We don't bat an eye at the quotidian death toll of cars or coal I've yet to see a nuclear safety argument that doesn't reduce to 'nuclear energy provokes emotional fear' Oh, it occasionally irradiates a swath of land and renders it uninhabitable? How about coal ash ponds or indefinite mine fires or infamous oil spills or dam failures or even the mining scars... Happy to be proven wrong, but https://ourworldindata.org/grapher/death-rates-from-energy-production-per-twh https://ourworldindata.org/grapher/death-rates-from-energy-p...
      - thrownthatway 6mo ago
        > it occasionally irradiates a swath That has happened exactly once.
        Kon5ole 6mo ago
- mm0lqf 6mo ago
  theres the well known inherent problem with the graphite at UK AGR reactors which could be very bad (can crack or misshape in such a way that the control rods or fuel rods cant be moved), not to mention the boiler cracking at the weldseams, they only mitigated this at some sites because they all are slightly different in design, they basically ignored it in the ones which didnt yet have it for decades ,the regulator ended up finding exactly that lessons learnt on older reactors were not being applied to newer ones which had the same problems inherent to them
- arijun 6mo ago
  I think the issue comes with unknown unknowns. Before Fukushima someone might have said the same thing you just have, but a new disaster still came along and caused a lot of issues. I am still bullish on nuclear, but I think waving away concerns might do more harm than good.
  - tshaddox 6mo ago
    Unknown design flaws in old nuclear power plants wouldn't be fixed in new nuclear power plants, unless if by chance.
  - AngryData 6mo ago
    Fukushima was a known risk though, they just never bothered to fix the problem. Plus just being planned in the 60s meant the initial design was born only about 15 years after nuclear power was invented. Fukishima was like driving around in a Model T, being told original brakes and tires and lack of seatbelts were unsafe, but still being regularly driven down busy roads without bothering to upgrade those features.
    - thrownthatway 6mo ago
      You reckon during the 44 years Fukushima Daiitchi operated there were no systems control and data acquisition upgrades? And you reckon that the site operated for 44 years on a Gen II design without melting down is somehow an insisted or how unsafe those reactors were. If that earthquake and tsunami had been only a bit different in either magnitude or location, those reactors could be operating still now. Or if the plant operated had hardened those backup generators and water pumps a bit more. There are 70 AP1000 reactors in operation, construction or planned. Look at this: Because of its simplified design compared to a Westinghouse generation II PWR, the AP1000 has: 50% fewer safety-related valves 35% fewer pumps 80% less safety-related piping 85% less control cable 45% less seismic building volume Isn’t this the kind of thing hackers and tech advocates should be getting a raging hardon over. This reactor does nearly twice as much as its predecessor using half the materials to build, at least for some systems.
      - 6mo ago
- legulere 6mo ago
  Chernobyl lacked a containment and there are still reactors of the same type running without containment in Russia.
  - thrownthatway 6mo ago
    There’s still 7 RMBK reactors running, I believe. And other than Chernobyl no melt downs. So they seem to be fairly reliable if they aren’t run by clowns.
  - mpweiher 6mo ago
    Well yes, Russia is Russia. The RBMK with its well-known design flaws could never have been certified/built in the West. Yes, these design flaws were well-known long before the Chernobyl accident. In his posthumously published memoirs, Valery Legasov, the First Deputy Director of the Kurchatov Institute of Atomic Energy, revealed that the institute's scientists had long known that the RBMK had significant design flaws. Legasov's suicide in 1988, following frustrated attempts to promote nuclear and industrial safety reform, caused shockwaves throughout the scientific community. https://en.wikipedia.org/wiki/RBMK#Improvements_since_the_Chernobyl_accident https://en.wikipedia.org/wiki/RBMK#Improvements_since_the_Ch... A list: https://en.wikipedia.org/wiki/RBMK#Design_flaws_and_safety_issues https://en.wikipedia.org/wiki/RBMK#Design_flaws_and_safety_i... However, the units that are still operating were modified after the accident to remove at least a few of the elements of the accident chain that made the reactor inherently unsafe. Still no containment, and still not anywhere close to the requirements for Western reactors, but they seem to be operating reasonably safely.
    - legulere 6mo ago
      How about the VVER-440 still running e.g. in the Czech Republic and Slovakia that lack proper containment? Still only Russia being Russia?
      - mpweiher 6mo ago
        The subject was modifications made to reactor types that had major accidents, and specifically the RBMK-1000. Last I checked, the VVER-440 is not an RBMK-1000, did not explode at Chernobyl, and has not had a major accident. "The two VVER-440 units in Loviisa, Finland have containment buildings that fulfil Western safety standards. A typical design feature of nuclear reactors is layered safety barriers preventing escape of radioactive material. VVER reactors have three layers: 1. Fuel rods: the hermetic zirconium alloy (Zircaloy) cladding around the uranium oxide sintered ceramic fuel pellets provides a barrier resistant to heat and high pressure. 2. Reactor pressure vessel wall: a massive steel shell encases the whole fuel assembly and primary coolant hermetically. 3. Reactor building: a concrete containment building that encases the whole first circuit is strong enough to resist the pressure surge a breach in the first circuit would cause. Compared to the RBMK reactors – the type involved in the Chernobyl disaster – the VVER uses an inherently safer design because the coolant is also the moderator, and by nature of its design has a negative void coefficient like all PWRs. It does not have the graphite-moderated RBMK's risk of increased reactivity and large power transients in the event of a loss of coolant accident. The RBMK reactors were also constructed without containment structures on grounds of cost due to their size; the VVER core is considerably smaller" https://en.wikipedia.org/wiki/VVER#Safety_barriers https://en.wikipedia.org/wiki/VVER#Safety_barriers It also appears that the VVER-440 does have a containment building, and older variants that had problems with said containment building were forced to shut down. "One of the earliest versions of the VVER-type, the VVER-440, manifested certain problems with its containment building design. As the V-230 and older models were from the outset not built to resist a design-critical large pipe break, the manufacturer added, with the newer V-213 model, a so called Bubble condenser tower that – with its additional volume and a number of water layers – aims to suppress the forces of rapidly escaping steam without the onset of a containment-leak. As a consequence, all member-countries[citation needed] with plants of the VVER-440 V-230 type, as well as older types, were forced by the politicians of the European Union to shut them down permanently. Because of this, the Bohunice Nuclear Power Plant had to close two reactors and the Kozloduy Nuclear Power Plant had to close four. Whereas in the case of the Greifswald Nuclear Power Plant, the German regulatory body had already made the same decision in the wake of the fall of the Berlin Wall."
leonidasrup 6mo ago
Nuclear reactors are regularly maintained, tested and checked. When possible, old plants are upgraded to new safety standards. You can upgrade certain components, and safety systems. However things like the containment structure or pressure vessel can't be changed. You for example can't retrofit a core catcher, but you could improve the turbines, I think Steam Generators as well, replace PLC's, Tsunami proof your site by building a larger tsunami wall / making your backup generators flood proof...
- cogman10 6mo ago
  Right, and ultimately Japan has decided the safest and I assume cheapest route with these reactors wasn't to rebuild but rather to decommission. These reactors can be made safer, but they all still have a foundational design flaw which means the ultimate goal should be replacing rather than continually spending money reinforcing.
  - leonidasrup 6mo ago
    On the contrary, Japan is changing it's energy policy and restarting it's nuclear reactors. "Japan’s Energy Plan: New Policy Shifts Nuclear Power Stance from Reduction to Maximization" https://www.nippon.com/en/in-depth/d01195/ https://www.nippon.com/en/in-depth/d01195/ https://www.reuters.com/sustainability/boards-policy-regulation/japan-prepares-restart-worlds-biggest-nuclear-plant-15-years-after-fukushima-2025-12-21/ https://www.reuters.com/sustainability/boards-policy-regulat...
    - cogman10 6mo ago
      Hmm, I may have been too vague. When I stated "these" I was talking specifically about the Fukushima plants and not Japan's policy for reactors nationally. Are they planning on restarting the Fukushima plants? I didn't think they were.
      - mpweiher 6mo ago
        The Fukushima plants were completely destroyed by the meltdowns and subsequent Hydrogen explosions that were caused by the Tsunami. There was never any chance of "restarting" them, so not sure why you brought that up.
boringg 6mo ago
> A healthy social attitude to nuclear would be to require periodic upgrades or decommissions as the plant ages. Tell me you don't work in energy without telling me. Most heavily regulated industry on the planet - constant upgrades and safety reports.
- cogman10 6mo ago
  Name a Gen II plant that was upgraded to a Gen III, III+ or Gen IV plant. There's a reason new Gen II plants cannot be built, and all the regulations and safety reports in the world will not fix the fundamental design flaw of these plants. We can mitigate and make meltdown less likely, we can't eliminate it without replacing the plants all together.
  - boringg 6mo ago
    The difference between different generations is wildly different and regulations aren't structured to allow for upgrading. It becomes a cost and regulatory burden thing - might as well rebuild then upgrade, very little to do with safety.
    - cogman10 6mo ago
      And I agree. I think this is a place where the regulations are broken. They should be changed to encourage new gen nuclear be built. Ideally, they could be tweaked so that the sites of old nuclear plants can be reused to produce new nuclear plants.
  - pyrale 6mo ago
    > Name a Gen II plant that was upgraded to a Gen III, III+ or Gen IV plant. That's a bit of an impossible ask. To give you a comparison with airplanes, F16 aren't "upgraded" to F35s. But there is an upgrade process, and F16s today are vastly different from F16s as they were in 1978. Likewise for nuclear plants, reviews are done following incidents and new discoveries, and overhauls are done, both in terms of process and material changes. Gen2 plants aren't the same as they were when they were built.
  - 6mo ago
davedx 6mo ago
Do you fly?
pqtyw 6mo ago
> Nuclear disasters happen at old plants. You used plural? What disasters are you talking about? Even Chernobyl wasn't technically first generation (not that it has anything to do with power plan safety in western countries anyway). Three Mile Island kind of proved it was fairly safe given that's the worst disaster to ever happen without any external factors (like tsunamis or being designed and run by soviet engineers..)
- arijun 6mo ago
  I may agree with your conclusion that old plants are safe enough (or at least take a deep dive study to see if their expected externality is worse than whatever would replace them). However: > the worst disaster to ever happen without any external factors The problem is external factors happen. You can’t just raise your hands up and say “wasn’t my fault,” when they do. A tsunami washing over a solar farm would be a lot safer than what happened at Fukushima.
  - BurningFrog 6mo ago
    The Fukushima quake was a truly extraordinary outlier though! 4th biggest quake ever recorded in history hit at the exact spot where the tsunami could overpower the protective wall at the reactor. Yet nobody died from the radiation. Meanwhile the 20k people who died in the tsunami are forgotten. No one demands we stop building cities by the ocean.
    - throwaway2037 6mo ago
      > Meanwhile the 20k people who died in the tsunami are forgotten. You are wrong. They are not forgotten.
- goodpoint 6mo ago
  I lost count at 50 https://en.wikipedia.org/wiki/Lists_of_nuclear_disasters_and_radioactive_incidents https://en.wikipedia.org/wiki/Lists_of_nuclear_disasters_and...
Moldoteck 6mo ago
safety is great and in some cases it can be improved. check out what great carenage is in france Even assuming all bad stuff, nuclear is statistically ok https://ourworldindata.org/safest-sources-of-energy https://ourworldindata.org/safest-sources-of-energy

thrownthatway 6mo ago

What nuclear disasters? Exactly? Name one nuclear disaster at an old nuclear plant whose lessons weren’t applied to the whole fleet.

cogman10 6mo ago
Fukushima. It was a Gen 1 plant which already has the issue that a thermal runaway is possible. There were other examples of this happening like TMI. The backup for Fukushima was onsite generators which were flooded and ultimately failed causing the meltdown. The safety lessons we learned from all gen 1 reactors was to apply passive shutdown mechanism where if input power fails fission ultimately stops. That's not something that can be applied across the fleet because it requires more infrastructure and an almost complete redesign of the reactor's setup. Which is why these early reactors all have a potential risk of thermal runaway. Edit: It looks like all gen Is have been decommissioned as of 2015, which is great. But we really should now be talking about decommissioning gen IIs and leaping forward to Gen IVs.
- navane 6mo ago
  That's a big nevertheless.
- leonidasrup 6mo ago
  Fukushima Daiichi Nuclear Power Plant was NOT using Generation I reactors. "Gen I refers to the prototype and power reactors that launched civil nuclear power. This generation consists of early prototype reactors from the 1950s and 1960s, such as Shippingport (1957–1982) in Pennsylvania, Dresden-1 (1960–1978) in Illinois, and Calder Hall-1 (1956–2003) in the United Kingdom. This kind of reactor typically ran at power levels that were “proof-of-concept.”" https://www.amacad.org/publication/nuclear-reactors-generation-generation/section/5 https://www.amacad.org/publication/nuclear-reactors-generati...
  - cogman10 6mo ago
    Got my gens mixed up, so thanks. But I think my point is still valid. These Gen II reactors should be retired and replaced.
- shawabawa3 6mo ago
  It's worth noting that the Fukoshima disaster 1. Lead to basically zero direct deaths 2. Was caused by the forth most powerful earthquake to have ever been recorded in the world (since ~1900), and the most powerful earthquake ever recorded in Japan 3. ~20,000 people died due to the Earthquake Requiring a nuclear plant in Belgium to be safe enough to survive what caused the Fukoshima disaster is probably not a good use of money
  - wholinator2 6mo ago
    I don't know but i feel like Nuclear reactors are something worth taking to the 99.99% percentile of safety. How much money does it really cost? And how does that money compare to the economic prosperity of the land that is currently radiation free. As well, i think us (assuming) not knowledgeable Nuclear engineers discussing the cost benefit of reactor safety should be basically locked out of the conversation. Plausible sounding soundbites are just too easily generated these days for anyone without credentials to have stake in these decisions.
    - swiftcoder 6mo ago
      > How much money does it really cost? The problem is as much time as it is money. We have reactors producing energy now, it will take a decade plus to replace them, and due to both climate policy and supply issues around the wars in Russia and the Middle East, we can't afford to do without the energy for that decade...
      - simondotau 6mo ago
        And if that nuclear would be displacing coal power, you have to consider the health and environmental costs of that coal generation which you haven't displaced.
      - thrownthatway 6mo ago
        > climate policy Fuck climate policy. There could be an earthquake any moment now that ruptures a massive natural CO formation that would eclipse any anthropogenic generated emissions in matter of hours. What have we done to mitigate that risk? Nothing. There is a non-zero chance Earth will be relieved of the responsibility of harbouring complex life any moment now by a loose pile of gravel travelling at 60 kilometres a second. Zero mitigation. Let’s work out this food-housing-energy deal for everyone before we mandate unaffordable unreliable energy that results in unaffordable everything. Maybe your shielded from that because your own a mid six figure income at $UNICORN, but I guarantee you the rest of us have had enough of this climate change fucking bullshit luxury belief.
- SoftTalker 6mo ago
  > if input power fails fission ultimately stops AIUI fission was stopped basically immediately. The problem was removing the decay heat from the fission by-products; without pumps to move cooling water that didn't happen. I think modern reactor designs have enough passive cooling that this failure mode can't happen. There are a lot of active reactor plants where it still could be possible though.
- thrownthatway 6mo ago
  Fukushima Daiichi is irrelevant to European nuclear reactor safety.
- deleted 6mo ago
  [deleted]
mannykannot 6mo ago
The claim that disasters happen to older plants is not refuted by the observation that lessons learned are applied to the whole fleet. One might object that there is selection bias in the original claim, due to the slowdown in construction of recent plants, but that is a separate issue. A more thorough investigation of the causes of all events leading to a significant degradation of safety margins would be needed to determine whether and how older designs are inherently more risky and whether that risk can be adequately mitigated given the constraints imposed by their design. The fact that, prior to Chernobyl, there were several foreshadowing incidents with RBMKs which should have raised serious concerns, suggests that 'lessons learned' isn't much of a reason to be satisfied with the status quo.
- thrownthatway 6mo ago
  RMBKs are irrelevant to nuclear reactor safety. You had a good argument up until you went there.
  - anonymars 6mo ago
    Even if we don't treat Chernobyl as sui generis, the safety situation with nuclear power is akin to that of airplanes. We don't bat an eye at the quotidian death toll of cars or coal I've yet to see a nuclear safety argument that doesn't reduce to 'nuclear energy provokes emotional fear' Oh, it occasionally irradiates a swath of land and renders it uninhabitable? How about coal ash ponds or indefinite mine fires or infamous oil spills or dam failures or even the mining scars... Happy to be proven wrong, but https://ourworldindata.org/grapher/death-rates-from-energy-production-per-twh https://ourworldindata.org/grapher/death-rates-from-energy-p...
    - thrownthatway 6mo ago
      > it occasionally irradiates a swath That has happened exactly once.
      - Kon5ole 6mo ago
mm0lqf 6mo ago
theres the well known inherent problem with the graphite at UK AGR reactors which could be very bad (can crack or misshape in such a way that the control rods or fuel rods cant be moved), not to mention the boiler cracking at the weldseams, they only mitigated this at some sites because they all are slightly different in design, they basically ignored it in the ones which didnt yet have it for decades ,the regulator ended up finding exactly that lessons learnt on older reactors were not being applied to newer ones which had the same problems inherent to them
arijun 6mo ago
I think the issue comes with unknown unknowns. Before Fukushima someone might have said the same thing you just have, but a new disaster still came along and caused a lot of issues. I am still bullish on nuclear, but I think waving away concerns might do more harm than good.
- tshaddox 6mo ago
  Unknown design flaws in old nuclear power plants wouldn't be fixed in new nuclear power plants, unless if by chance.
- AngryData 6mo ago
  Fukushima was a known risk though, they just never bothered to fix the problem. Plus just being planned in the 60s meant the initial design was born only about 15 years after nuclear power was invented. Fukishima was like driving around in a Model T, being told original brakes and tires and lack of seatbelts were unsafe, but still being regularly driven down busy roads without bothering to upgrade those features.
  - thrownthatway 6mo ago
    You reckon during the 44 years Fukushima Daiitchi operated there were no systems control and data acquisition upgrades? And you reckon that the site operated for 44 years on a Gen II design without melting down is somehow an insisted or how unsafe those reactors were. If that earthquake and tsunami had been only a bit different in either magnitude or location, those reactors could be operating still now. Or if the plant operated had hardened those backup generators and water pumps a bit more. There are 70 AP1000 reactors in operation, construction or planned. Look at this: Because of its simplified design compared to a Westinghouse generation II PWR, the AP1000 has: 50% fewer safety-related valves 35% fewer pumps 80% less safety-related piping 85% less control cable 45% less seismic building volume Isn’t this the kind of thing hackers and tech advocates should be getting a raging hardon over. This reactor does nearly twice as much as its predecessor using half the materials to build, at least for some systems.
    - 6mo ago
legulere 6mo ago
Chernobyl lacked a containment and there are still reactors of the same type running without containment in Russia.
- thrownthatway 6mo ago
  There’s still 7 RMBK reactors running, I believe. And other than Chernobyl no melt downs. So they seem to be fairly reliable if they aren’t run by clowns.
- mpweiher 6mo ago
  Well yes, Russia is Russia. The RBMK with its well-known design flaws could never have been certified/built in the West. Yes, these design flaws were well-known long before the Chernobyl accident. In his posthumously published memoirs, Valery Legasov, the First Deputy Director of the Kurchatov Institute of Atomic Energy, revealed that the institute's scientists had long known that the RBMK had significant design flaws. Legasov's suicide in 1988, following frustrated attempts to promote nuclear and industrial safety reform, caused shockwaves throughout the scientific community. https://en.wikipedia.org/wiki/RBMK#Improvements_since_the_Chernobyl_accident https://en.wikipedia.org/wiki/RBMK#Improvements_since_the_Ch... A list: https://en.wikipedia.org/wiki/RBMK#Design_flaws_and_safety_issues https://en.wikipedia.org/wiki/RBMK#Design_flaws_and_safety_i... However, the units that are still operating were modified after the accident to remove at least a few of the elements of the accident chain that made the reactor inherently unsafe. Still no containment, and still not anywhere close to the requirements for Western reactors, but they seem to be operating reasonably safely.
  - legulere 6mo ago
    How about the VVER-440 still running e.g. in the Czech Republic and Slovakia that lack proper containment? Still only Russia being Russia?
    - mpweiher 6mo ago
      The subject was modifications made to reactor types that had major accidents, and specifically the RBMK-1000. Last I checked, the VVER-440 is not an RBMK-1000, did not explode at Chernobyl, and has not had a major accident. "The two VVER-440 units in Loviisa, Finland have containment buildings that fulfil Western safety standards. A typical design feature of nuclear reactors is layered safety barriers preventing escape of radioactive material. VVER reactors have three layers: 1. Fuel rods: the hermetic zirconium alloy (Zircaloy) cladding around the uranium oxide sintered ceramic fuel pellets provides a barrier resistant to heat and high pressure. 2. Reactor pressure vessel wall: a massive steel shell encases the whole fuel assembly and primary coolant hermetically. 3. Reactor building: a concrete containment building that encases the whole first circuit is strong enough to resist the pressure surge a breach in the first circuit would cause. Compared to the RBMK reactors – the type involved in the Chernobyl disaster – the VVER uses an inherently safer design because the coolant is also the moderator, and by nature of its design has a negative void coefficient like all PWRs. It does not have the graphite-moderated RBMK's risk of increased reactivity and large power transients in the event of a loss of coolant accident. The RBMK reactors were also constructed without containment structures on grounds of cost due to their size; the VVER core is considerably smaller" https://en.wikipedia.org/wiki/VVER#Safety_barriers https://en.wikipedia.org/wiki/VVER#Safety_barriers It also appears that the VVER-440 does have a containment building, and older variants that had problems with said containment building were forced to shut down. "One of the earliest versions of the VVER-type, the VVER-440, manifested certain problems with its containment building design. As the V-230 and older models were from the outset not built to resist a design-critical large pipe break, the manufacturer added, with the newer V-213 model, a so called Bubble condenser tower that – with its additional volume and a number of water layers – aims to suppress the forces of rapidly escaping steam without the onset of a containment-leak. As a consequence, all member-countries[citation needed] with plants of the VVER-440 V-230 type, as well as older types, were forced by the politicians of the European Union to shut them down permanently. Because of this, the Bohunice Nuclear Power Plant had to close two reactors and the Kozloduy Nuclear Power Plant had to close four. Whereas in the case of the Greifswald Nuclear Power Plant, the German regulatory body had already made the same decision in the wake of the fall of the Berlin Wall."

leonidasrup 6mo ago

Nuclear reactors are regularly maintained, tested and checked. When possible, old plants are upgraded to new safety standards. You can upgrade certain components, and safety systems. However things like the containment structure or pressure vessel can't be changed. You for example can't retrofit a core catcher, but you could improve the turbines, I think Steam Generators as well, replace PLC's, Tsunami proof your site by building a larger tsunami wall / making your backup generators flood proof...

cogman10 6mo ago
Right, and ultimately Japan has decided the safest and I assume cheapest route with these reactors wasn't to rebuild but rather to decommission. These reactors can be made safer, but they all still have a foundational design flaw which means the ultimate goal should be replacing rather than continually spending money reinforcing.
- leonidasrup 6mo ago
  On the contrary, Japan is changing it's energy policy and restarting it's nuclear reactors. "Japan’s Energy Plan: New Policy Shifts Nuclear Power Stance from Reduction to Maximization" https://www.nippon.com/en/in-depth/d01195/ https://www.nippon.com/en/in-depth/d01195/ https://www.reuters.com/sustainability/boards-policy-regulation/japan-prepares-restart-worlds-biggest-nuclear-plant-15-years-after-fukushima-2025-12-21/ https://www.reuters.com/sustainability/boards-policy-regulat...
  - cogman10 6mo ago
    Hmm, I may have been too vague. When I stated "these" I was talking specifically about the Fukushima plants and not Japan's policy for reactors nationally. Are they planning on restarting the Fukushima plants? I didn't think they were.
    - mpweiher 6mo ago
      The Fukushima plants were completely destroyed by the meltdowns and subsequent Hydrogen explosions that were caused by the Tsunami. There was never any chance of "restarting" them, so not sure why you brought that up.

boringg 6mo ago

> A healthy social attitude to nuclear would be to require periodic upgrades or decommissions as the plant ages. Tell me you don't work in energy without telling me. Most heavily regulated industry on the planet - constant upgrades and safety reports.

cogman10 6mo ago
Name a Gen II plant that was upgraded to a Gen III, III+ or Gen IV plant. There's a reason new Gen II plants cannot be built, and all the regulations and safety reports in the world will not fix the fundamental design flaw of these plants. We can mitigate and make meltdown less likely, we can't eliminate it without replacing the plants all together.
- boringg 6mo ago
  The difference between different generations is wildly different and regulations aren't structured to allow for upgrading. It becomes a cost and regulatory burden thing - might as well rebuild then upgrade, very little to do with safety.
  - cogman10 6mo ago
    And I agree. I think this is a place where the regulations are broken. They should be changed to encourage new gen nuclear be built. Ideally, they could be tweaked so that the sites of old nuclear plants can be reused to produce new nuclear plants.
- pyrale 6mo ago
  > Name a Gen II plant that was upgraded to a Gen III, III+ or Gen IV plant. That's a bit of an impossible ask. To give you a comparison with airplanes, F16 aren't "upgraded" to F35s. But there is an upgrade process, and F16s today are vastly different from F16s as they were in 1978. Likewise for nuclear plants, reviews are done following incidents and new discoveries, and overhauls are done, both in terms of process and material changes. Gen2 plants aren't the same as they were when they were built.
- 6mo ago

davedx 6mo ago

Do you fly?

pqtyw 6mo ago

> Nuclear disasters happen at old plants. You used plural? What disasters are you talking about? Even Chernobyl wasn't technically first generation (not that it has anything to do with power plan safety in western countries anyway). Three Mile Island kind of proved it was fairly safe given that's the worst disaster to ever happen without any external factors (like tsunamis or being designed and run by soviet engineers..)

arijun 6mo ago
I may agree with your conclusion that old plants are safe enough (or at least take a deep dive study to see if their expected externality is worse than whatever would replace them). However: > the worst disaster to ever happen without any external factors The problem is external factors happen. You can’t just raise your hands up and say “wasn’t my fault,” when they do. A tsunami washing over a solar farm would be a lot safer than what happened at Fukushima.
- BurningFrog 6mo ago
  The Fukushima quake was a truly extraordinary outlier though! 4th biggest quake ever recorded in history hit at the exact spot where the tsunami could overpower the protective wall at the reactor. Yet nobody died from the radiation. Meanwhile the 20k people who died in the tsunami are forgotten. No one demands we stop building cities by the ocean.
  - throwaway2037 6mo ago
    > Meanwhile the 20k people who died in the tsunami are forgotten. You are wrong. They are not forgotten.
goodpoint 6mo ago
I lost count at 50 https://en.wikipedia.org/wiki/Lists_of_nuclear_disasters_and_radioactive_incidents https://en.wikipedia.org/wiki/Lists_of_nuclear_disasters_and...

Moldoteck 6mo ago

safety is great and in some cases it can be improved. check out what great carenage is in france Even assuming all bad stuff, nuclear is statistically ok https://ourworldindata.org/safest-sources-of-energy https://ourworldindata.org/safest-sources-of-energy