9 ms·

Leaks are designed out because the entire reactor vessels are surrounded by a giant swimming pool. The temperature stays low enough because this swimming pool i

Leaks are designed out because the entire reactor vessels are surrounded by a giant swimming pool. The temperature stays low enough because this swimming pool is passively cooled. Lack of relible decay heat[1] cooling caused both Fukushima and three mile island accidents. Having passive decay heat removal usually decreases the probability of core damage by about 100x. 1 https://whatisnuclear.com/decay-heat.html https://whatisnuclear.com/decay-heat.html

benj111 8y ago
"Having passive decay heat removal usually decreases the probability of core damage by about 100x." 100x isn't 100% though. 100 of these small reactors has the same risk as one large reactor. Perhaps higher, because like you, everyone goes around saying the risk has been designed out. Though obviously one small reactor going boom is preferable to a big one doing the same.
- acidburnNSA 8y ago
  100% safe is never the metric. Nothing is 100% safe. Every form of energy generation has risks that have to balance the good the energy source brings. Nuclear is nearly unique in that it can produce carbon-free energy (unlike fossil and biomass), continuously for 2 years on end between reloads (unlike wind/solar/coal), and it can be deployed in a wide variety of geographic locations (unlike hydro and geothermal). The risk is that there are occasionally nuclear accidents: Three mile island and fermi 1 meltdowns, both of which killed zero people. Chernobyl, which killed ~50 from ARS and up to 4,000 early deaths over the next several decades (on top of a few million cancers that would have happened anyway in the population). Fukushima, which killed up to one person. Can anyone name any fatal natural gas explosions? Any hydro dam failures that killed 100,000? How many people per year does coal kill by operating normally (~200,000). We as a society accept certain risks from our energy infrastructure because of all the good we get from it. Here is a plot of how many thousands of days of life are lost by various things [1]. Note that nuclear is almost ridiculously low. This chart doesn't include the impact of climate change on human lives. Nuclear fission is a climate superpower, and we cannot be justified in neglecting this natural resource because we're afraid of something going boom. TLDR: A factor of 100x improvement in nuclear safety goes from tiny risk to supertiny. Current plants are already safer than almost everything else we know. Some studies have more people dying from installing solar on their roofs than getting killed by radiation from nuclear fission plants. [1] https://i.imgur.com/ClgbpA4.png https://i.imgur.com/ClgbpA4.png
  - v_lisivka 8y ago
    Yeah, even Sun will blow and destroy our Solar system, so solar energy is not safe too. BTW: Will you move to Chornobyl to demonstrate that radioactivity is safe? Land is cheap here.
    - acidburnNSA 8y ago
      Sure, if my family and job were there. Its a thriving wildlife refuge now. Check it out. https://thoughtscapism.com/2019/05/08/worlds-worst-energy-accidents-in-environmental-perspective/ https://thoughtscapism.com/2019/05/08/worlds-worst-energy-ac...
      - uterus-liner 8y ago
        Pretty tough talk, posting comments on the internet. You have convenient excuses, and a lot of talk. How about you actually do it?
      - v_lisivka 8y ago
        I can drive to Chornobyl by bicycle. I just don't want that. Wildlife is thriving in my area too, because people abandon homes and move to cities instead. However, if you like it, you can create similar exclusion zone near to you. Just vote for nuclear power and wait until next nuclear disaster.
        AstralStorm 8y ago
        Come on. You can drive nearly to the reactor itself and not even get a yearly background radiation dose now. There are a few hot spots where contaminated gear from decommissioning is stored, that's it. People got cancers at increased rate, which is limited to less than two generations of damage. The range had expired a bunch of years ago. Going into high mountains is a bigger radiation risk today. As a bonus, you can just drive to Fukushima on a bike today and not even get a daily dose of some inhabited places in the US.
        8y ago
C1sc0cat 8y ago
What happens if the swimming pool leaks ?
- rwcarlsen 8y ago
  The pool only needs to function for a few days during/after an accident until heat energy from fission product decay reduces to lower levels. The pool's function is as an accident mitigation measure - and when any accident occurs the reactor enters a "shut down" state. The decay heat energy that needs to be dissipated is much lower than normal reactor operational power output.
- CodeCube 8y ago
  I mean ... millions of people who barely maintain their homes avoid pool leaks, and when it does leak, it tends to be slow enough that they can call in a professional to fix the problem. Imagine a fastidiously maintained facility ... I think they can probably work it out
  - 781 8y ago
    You have to consider stuff like terrorist attack and so on. Nobody is so incentivized in making your backyard pool leak.
    - jcranmer 8y ago
      What if a dam explodes? More people have died due to dam failures (both intentional and accidental) than have died to nuclear power, but there is nowhere near the freaking out over the safety of dams compared to nuclear power. For comparison, the Banqiao Dam failure (the largest dam failure in history) killed as many people as the sum total of every nuclear power plant failure and every atomic bomb ever used, combined.
      - petschge 8y ago
        While dam break cost lives, there is crucial differences that are never mentioned by the pro-nuclear crowd on HN. 1.) Dam breaks devastate much smaller areas. So even if the human toll is the same, the amount of infrastructure lost is smaller. 2.) The area is unlivable (or even inaccessible) for a much smaller duration of month instead of millenia. Maybe land lost "forever" (on the timescale of individual human lives) is not a big problem in some part of the world, but in densely populated areas (any they need the most power, so would have MORE reactors per area) you can not simply block off an area the size of Belgium because a reactor exploded. This makes nuclear power a lot less attractive in India, Europe or (coastal) China.

benj111 8y ago

"Having passive decay heat removal usually decreases the probability of core damage by about 100x." 100x isn't 100% though. 100 of these small reactors has the same risk as one large reactor. Perhaps higher, because like you, everyone goes around saying the risk has been designed out. Though obviously one small reactor going boom is preferable to a big one doing the same.

acidburnNSA 8y ago
100% safe is never the metric. Nothing is 100% safe. Every form of energy generation has risks that have to balance the good the energy source brings. Nuclear is nearly unique in that it can produce carbon-free energy (unlike fossil and biomass), continuously for 2 years on end between reloads (unlike wind/solar/coal), and it can be deployed in a wide variety of geographic locations (unlike hydro and geothermal). The risk is that there are occasionally nuclear accidents: Three mile island and fermi 1 meltdowns, both of which killed zero people. Chernobyl, which killed ~50 from ARS and up to 4,000 early deaths over the next several decades (on top of a few million cancers that would have happened anyway in the population). Fukushima, which killed up to one person. Can anyone name any fatal natural gas explosions? Any hydro dam failures that killed 100,000? How many people per year does coal kill by operating normally (~200,000). We as a society accept certain risks from our energy infrastructure because of all the good we get from it. Here is a plot of how many thousands of days of life are lost by various things [1]. Note that nuclear is almost ridiculously low. This chart doesn't include the impact of climate change on human lives. Nuclear fission is a climate superpower, and we cannot be justified in neglecting this natural resource because we're afraid of something going boom. TLDR: A factor of 100x improvement in nuclear safety goes from tiny risk to supertiny. Current plants are already safer than almost everything else we know. Some studies have more people dying from installing solar on their roofs than getting killed by radiation from nuclear fission plants. [1] https://i.imgur.com/ClgbpA4.png https://i.imgur.com/ClgbpA4.png
- v_lisivka 8y ago
  Yeah, even Sun will blow and destroy our Solar system, so solar energy is not safe too. BTW: Will you move to Chornobyl to demonstrate that radioactivity is safe? Land is cheap here.
  - acidburnNSA 8y ago
    Sure, if my family and job were there. Its a thriving wildlife refuge now. Check it out. https://thoughtscapism.com/2019/05/08/worlds-worst-energy-accidents-in-environmental-perspective/ https://thoughtscapism.com/2019/05/08/worlds-worst-energy-ac...
    - uterus-liner 8y ago
      Pretty tough talk, posting comments on the internet. You have convenient excuses, and a lot of talk. How about you actually do it?
    - v_lisivka 8y ago
      I can drive to Chornobyl by bicycle. I just don't want that. Wildlife is thriving in my area too, because people abandon homes and move to cities instead. However, if you like it, you can create similar exclusion zone near to you. Just vote for nuclear power and wait until next nuclear disaster.
      - AstralStorm 8y ago
        Come on. You can drive nearly to the reactor itself and not even get a yearly background radiation dose now. There are a few hot spots where contaminated gear from decommissioning is stored, that's it. People got cancers at increased rate, which is limited to less than two generations of damage. The range had expired a bunch of years ago. Going into high mountains is a bigger radiation risk today. As a bonus, you can just drive to Fukushima on a bike today and not even get a daily dose of some inhabited places in the US.
        8y ago

C1sc0cat 8y ago

What happens if the swimming pool leaks ?

rwcarlsen 8y ago
The pool only needs to function for a few days during/after an accident until heat energy from fission product decay reduces to lower levels. The pool's function is as an accident mitigation measure - and when any accident occurs the reactor enters a "shut down" state. The decay heat energy that needs to be dissipated is much lower than normal reactor operational power output.
CodeCube 8y ago
I mean ... millions of people who barely maintain their homes avoid pool leaks, and when it does leak, it tends to be slow enough that they can call in a professional to fix the problem. Imagine a fastidiously maintained facility ... I think they can probably work it out
- 781 8y ago
  You have to consider stuff like terrorist attack and so on. Nobody is so incentivized in making your backyard pool leak.
  - jcranmer 8y ago
    What if a dam explodes? More people have died due to dam failures (both intentional and accidental) than have died to nuclear power, but there is nowhere near the freaking out over the safety of dams compared to nuclear power. For comparison, the Banqiao Dam failure (the largest dam failure in history) killed as many people as the sum total of every nuclear power plant failure and every atomic bomb ever used, combined.
    - petschge 8y ago
      While dam break cost lives, there is crucial differences that are never mentioned by the pro-nuclear crowd on HN. 1.) Dam breaks devastate much smaller areas. So even if the human toll is the same, the amount of infrastructure lost is smaller. 2.) The area is unlivable (or even inaccessible) for a much smaller duration of month instead of millenia. Maybe land lost "forever" (on the timescale of individual human lives) is not a big problem in some part of the world, but in densely populated areas (any they need the most power, so would have MORE reactors per area) you can not simply block off an area the size of Belgium because a reactor exploded. This makes nuclear power a lot less attractive in India, Europe or (coastal) China.