5 ms·

Given how much experience we have with this class of reactors, and the inherent safety of PWRs (e.g. TMI, vs. BWRs like a Fukushima), and that the organization

by hga 11y ago

Given how much experience we have with this class of reactors, and the inherent safety of PWRs (e.g. TMI, vs. BWRs like a Fukushima), and that the organization running it has long, continuous experience in running these, not much, I'd expect. They only unique danger comes from it being mothballed for so long, and the possibility that resulted in undetected degradation (anything more that corrosion?).

zamalek 11y ago
Agreed. If PBR is to be taken as the flagship of reactor safety (physics prevents a problem from ever occurring), the safety features in Gen II PWR come pretty damn close. You'd need a long cascade of extremely unlikely events in order for it to dangerously fail, for example, the reactor vessel being bent so that the rods are unable to be affected by gravity. Having first breached the concrete and steel whatever caused the catastrophe would also need to bend uranium.
- hga 11y ago
  Indeed. TMI was pretty close to a worst case disaster for a PWR with a partial, uncontrolled meltdown, with a lot of corium ending up on the bottom of the vessel where it did exactly what was planned, sat there not particularly bothering anyone except the company which would have really rather continued generating power from the reactor. I'd have to double check, but as I recall if you were standing outside the containment vessel, you'd have received the dosage you'd get from sleeping with two other people (potassium-40) ... which we should clearly outlaw right now due to that grave danger (along with living in the Mile High city of Denver, commercial jetliner travel, and eating bananas).
  - 3JPLW 11y ago
    > a lot of corium ending up on the bottom of the vessel where it did exactly what was planned Yes, that's what happened, but I wouldn't say it was planned. Popular wisdom at the time was that the corium should have melted the whole way through the containment vessel. It was only afterwards that they discovered that the water and corium itself helped keep the steel containment vessel cool enough to prevent melting (albeit just barely).[1] Yes, almost no radiation was released. But we got very lucky. It was close to melting through the containment vessel. "By some estimates, the core was 30 minutes away from melting through the eight-inch-thick steel reactor vessel when cooling water was finally restored."[2] 1. http://articles.latimes.com/1994-01-30/news/mn-17003_1_nuclear-fuel http://articles.latimes.com/1994-01-30/news/mn-17003_1_nucle... 2. https://www.washingtonpost.com/wp-srv/national/longterm/tmi/stories/cleanup032889.htm https://www.washingtonpost.com/wp-srv/national/longterm/tmi/...
    - hga 11y ago
      Yes, that's what happened, but I wouldn't say it was planned. Popular wisdom at the time was that the corium should have melted the whole way through the containment vessel. The "popular wisdom" is utter propaganda bullshit; have you ever wondered why the popular at the time and mentioned in [1] "China Syndrome" is for some inexplicable reason is not longer bandied about? The design of the reactor vessel allowed for this and withstood the stress without the bigger concrete containment vessel even coming into play. Note even in [1]: Besides the insulating property of the fuel and the strength of the steel vessel, previous studies had shown the concrete bases on which U.S. reactors are built also would hold up against melting fuel, Beckjord said. That you are confounding the reactor and containment vessels in your posting suggests to me how effective that propaganda has been.
- rsync 11y ago
  I don't have anything new to say about TMI/PBR/PBM, etc., however this sentence stands out: "You'd need a long cascade of extremely unlikely events in order for it to dangerously fail" Have we learned nothing at all ? Even when given extremely relevant and instructive examples within the last 10 years ? From Fukushima to Lehman Brothers, we continue to be shown that these unlikely events are highly correlated - even if they are extremely unlikely individually. The Tsunami comes with the Earthquake
  - zamalek 11y ago
    > Fukushima With Fukushima they knew what the problems were and chose to make an half-assed attempt at safety - for example: the 2008 Tsunami study was ignored. I guess what could be surmised is that nuclear power is only completely safe in the absence of human nature. Which makes you correct in a round-about way. However, it is unsafe in comparison to what? Nine times out of ten not being able to breath anywhere on the planet, forever, seems like the more dangerous prospect; versus making a specific piece of land uninhabitable for a few thousand years. Nuclear waste is far easier to see, which makes us more aware of it and hence our monkey brains believe it is more dangerous ("smoke just dissolves into the air!"). I can't think of any power solution that doesn't have severe drawbacks; however, nuclear is at the very least not the top contender in that list.
    - smileysteve 11y ago
      > However, it is unsafe in comparison to what? Nine times out of ten not being able to breath anywhere on the planet, forever, seems like the more dangerous prospect; The arsenic and other emissions from a coal plant are roughly measurable to a nuclear MELTDOWN every 10 years.
      - zamalek 11y ago
        ... and because of the current anti-nuclear sentiment, when South Africa faced a power crisis they decided to build the biggest coal power plant in the southern hemisphere[1]. I honestly can in no small way whatsoever see that as a win for the environment. [1]: https://en.wikipedia.org/wiki/Medupi_Power_Station https://en.wikipedia.org/wiki/Medupi_Power_Station Thanks for that factoid.

by hga 11y ago

zamalek 11y ago

Agreed. If PBR is to be taken as the flagship of reactor safety (physics prevents a problem from ever occurring), the safety features in Gen II PWR come pretty damn close. You'd need a long cascade of extremely unlikely events in order for it to dangerously fail, for example, the reactor vessel being bent so that the rods are unable to be affected by gravity. Having first breached the concrete and steel whatever caused the catastrophe would also need to bend uranium.

hga 11y ago
Indeed. TMI was pretty close to a worst case disaster for a PWR with a partial, uncontrolled meltdown, with a lot of corium ending up on the bottom of the vessel where it did exactly what was planned, sat there not particularly bothering anyone except the company which would have really rather continued generating power from the reactor. I'd have to double check, but as I recall if you were standing outside the containment vessel, you'd have received the dosage you'd get from sleeping with two other people (potassium-40) ... which we should clearly outlaw right now due to that grave danger (along with living in the Mile High city of Denver, commercial jetliner travel, and eating bananas).
- 3JPLW 11y ago
  > a lot of corium ending up on the bottom of the vessel where it did exactly what was planned Yes, that's what happened, but I wouldn't say it was planned. Popular wisdom at the time was that the corium should have melted the whole way through the containment vessel. It was only afterwards that they discovered that the water and corium itself helped keep the steel containment vessel cool enough to prevent melting (albeit just barely).[1] Yes, almost no radiation was released. But we got very lucky. It was close to melting through the containment vessel. "By some estimates, the core was 30 minutes away from melting through the eight-inch-thick steel reactor vessel when cooling water was finally restored."[2] 1. http://articles.latimes.com/1994-01-30/news/mn-17003_1_nuclear-fuel http://articles.latimes.com/1994-01-30/news/mn-17003_1_nucle... 2. https://www.washingtonpost.com/wp-srv/national/longterm/tmi/stories/cleanup032889.htm https://www.washingtonpost.com/wp-srv/national/longterm/tmi/...
  - hga 11y ago
    Yes, that's what happened, but I wouldn't say it was planned. Popular wisdom at the time was that the corium should have melted the whole way through the containment vessel. The "popular wisdom" is utter propaganda bullshit; have you ever wondered why the popular at the time and mentioned in [1] "China Syndrome" is for some inexplicable reason is not longer bandied about? The design of the reactor vessel allowed for this and withstood the stress without the bigger concrete containment vessel even coming into play. Note even in [1]: Besides the insulating property of the fuel and the strength of the steel vessel, previous studies had shown the concrete bases on which U.S. reactors are built also would hold up against melting fuel, Beckjord said. That you are confounding the reactor and containment vessels in your posting suggests to me how effective that propaganda has been.
rsync 11y ago
I don't have anything new to say about TMI/PBR/PBM, etc., however this sentence stands out: "You'd need a long cascade of extremely unlikely events in order for it to dangerously fail" Have we learned nothing at all ? Even when given extremely relevant and instructive examples within the last 10 years ? From Fukushima to Lehman Brothers, we continue to be shown that these unlikely events are highly correlated - even if they are extremely unlikely individually. The Tsunami comes with the Earthquake
- zamalek 11y ago
  > Fukushima With Fukushima they knew what the problems were and chose to make an half-assed attempt at safety - for example: the 2008 Tsunami study was ignored. I guess what could be surmised is that nuclear power is only completely safe in the absence of human nature. Which makes you correct in a round-about way. However, it is unsafe in comparison to what? Nine times out of ten not being able to breath anywhere on the planet, forever, seems like the more dangerous prospect; versus making a specific piece of land uninhabitable for a few thousand years. Nuclear waste is far easier to see, which makes us more aware of it and hence our monkey brains believe it is more dangerous ("smoke just dissolves into the air!"). I can't think of any power solution that doesn't have severe drawbacks; however, nuclear is at the very least not the top contender in that list.
  - smileysteve 11y ago
    > However, it is unsafe in comparison to what? Nine times out of ten not being able to breath anywhere on the planet, forever, seems like the more dangerous prospect; The arsenic and other emissions from a coal plant are roughly measurable to a nuclear MELTDOWN every 10 years.
    - zamalek 11y ago
      ... and because of the current anti-nuclear sentiment, when South Africa faced a power crisis they decided to build the biggest coal power plant in the southern hemisphere[1]. I honestly can in no small way whatsoever see that as a win for the environment. [1]: https://en.wikipedia.org/wiki/Medupi_Power_Station https://en.wikipedia.org/wiki/Medupi_Power_Station Thanks for that factoid.