5 ms·

> our undergrad reactor thermohydraulics class's professor was notoriously strict because there's just no tolerance for failing to do the math for cooling a rea

> our undergrad reactor thermohydraulics class's professor was notoriously strict because there's just no tolerance for failing to do the math for cooling a reactor. How is this different from calculating any other design?

kurthr 9y ago
Because, in a "normal" case of a large suspension bridge failing, you might kill 20-30, if a bus was going over as it failed. Fixing it might cost $Bs. In the case of a nuclear meltdown (or "temporary fission surplus") you might acutely impact 10-100s of million people and significantly shorten the lives of several 10s of thousand (see Chernobyl). Costs might range into the many $100Bs.
- rdiddly 9y ago
  If structural engineering were a relaxed and informal field with a lot of trial and error and no entry requirements, your example we be a good one.
  - deleted 9y ago
    [deleted]
- rdiddly 9y ago
  Zero loss of life is considered acceptable in any non-military field of engineering or design that I'm aware of. (With the possible exception of automotive and highway design, where we have a huge blind spot, but that's a topic for another day.) Bridge collapses and nuclear accidents both tend to produce non-zero loss of life, and be considered shall-we-say "bad." So they are treated exactly the same by their respective fields; namely, zero such incidents are tolerated, allowed or expected. Which means your example doesn't demonstrate a difference or answer the question "How is this different from calculating any other design?" Nobody allows collapsing a bridge just because it "only" kills 30 people. (By the way, the Golden Gate is about 8,000 feet long, a car is about 25 feet long, let's say 30 including buffer space, and there are 6 lanes. So if traffic is bumper-to-bumper, everybody is in their car alone, and there are no trucks or buses, that means there are about 1,600 people on the bridge. More if there are buses and carpools, less if there are trucks.) If you wanted to show a difference, you would have to pick a field of design where catastrophic failures are tolerated and calculation accuracy isn't such a big deal, such as the shitty web apps we all work on. Unfortunately you picked structural engineering, where as far as I know they require 6 years of school, 4 years of mentoring and two all-day exams just for licensure, at least two engineers have to sign off on every design, and both of those engineers are held personally liable (read financially and professionally ruined) for any negligence resulting in an accident. It's a non-illustrative example.
  - kurthr 9y ago
    How many bridge failures are likely to dirrectly affect people in another state or country with different laws and standards for construction without their knowledge? Which nuclear accident affected all of Europe? How many bridge failures are there per year? How many people die on average? Can you name one with greater than 150 casualties? Let me help: https://www.wikipedia.org/wiki/List_of_bridge_failures https://www.wikipedia.org/wiki/List_of_bridge_failures https://www.wikipedia.org/wiki/Chernobyl_disaster https://www.wikipedia.org/wiki/Chernobyl_disaster Now if you want to talk about tsunami, that's a different topi, but it's pretty clear why the design, review, and construction of nuclear power plants are more restrictive than even the largest and most expensive bridges (or other civil engineering projects with the possible exception of dams).
    - rdiddly 9y ago
      As I tried so hard to point out, "which accident is worse" is not the point. They are both unallowably bad. You are correct that a serious nuclear accident is likely worse than a bridge collapse. The question was how and whether mistakes in nuclear design are treated differently from other engineering fields. You brought up bridge collapses, which is a bad example because mistakes aren't tolerated in bridge design either. Or in structural engineering in general, which includes the design of nuclear plants by the way. You now bring up frequency of bridge collapses per year, which doesn't seem relevant either. Or if we somehow decide it's relevant, it's actually a counter-indicator to your point. Because if it's a low number, that means the bridge field probably takes mistakes very seriously and ferrets them out successfully. And if it's a high number, that starts to weaken your point about "which is worse." But the number would have to be pretty big to compete, and we would stop building bridges long before reaching it, and again it's not about which is worse. You finally address the point in the last line. Educate me about those design/review/construction restrictions if you like.
      - kurthr 9y ago
        I am not certain you will find the equivalent of the NRC, the IAEA, the NEPIO, or various international treaties involving most (any?) other construction projects. https://www.iaea.org/topics/construction-and-commissioning-of-nuclear-power-plants https://www.iaea.org/topics/construction-and-commissioning-o... Why wouldn't you want a random state, local, or national business design and regulate a unique nuclear power plant? What could possibly go wrong? LOL! To be clear the number of unique (because looks are important) bridge designs proliferates and the suppliers change regularly while every new nuclear reactor is a close derivative of one that has been built and tested for decades. That's not because it's the easiest or highest profit, but because international regulation and public fear are real.

kurthr 9y ago

Because, in a "normal" case of a large suspension bridge failing, you might kill 20-30, if a bus was going over as it failed. Fixing it might cost $Bs. In the case of a nuclear meltdown (or "temporary fission surplus") you might acutely impact 10-100s of million people and significantly shorten the lives of several 10s of thousand (see Chernobyl). Costs might range into the many $100Bs.

rdiddly 9y ago
If structural engineering were a relaxed and informal field with a lot of trial and error and no entry requirements, your example we be a good one.
- deleted 9y ago
  [deleted]
rdiddly 9y ago
Zero loss of life is considered acceptable in any non-military field of engineering or design that I'm aware of. (With the possible exception of automotive and highway design, where we have a huge blind spot, but that's a topic for another day.) Bridge collapses and nuclear accidents both tend to produce non-zero loss of life, and be considered shall-we-say "bad." So they are treated exactly the same by their respective fields; namely, zero such incidents are tolerated, allowed or expected. Which means your example doesn't demonstrate a difference or answer the question "How is this different from calculating any other design?" Nobody allows collapsing a bridge just because it "only" kills 30 people. (By the way, the Golden Gate is about 8,000 feet long, a car is about 25 feet long, let's say 30 including buffer space, and there are 6 lanes. So if traffic is bumper-to-bumper, everybody is in their car alone, and there are no trucks or buses, that means there are about 1,600 people on the bridge. More if there are buses and carpools, less if there are trucks.) If you wanted to show a difference, you would have to pick a field of design where catastrophic failures are tolerated and calculation accuracy isn't such a big deal, such as the shitty web apps we all work on. Unfortunately you picked structural engineering, where as far as I know they require 6 years of school, 4 years of mentoring and two all-day exams just for licensure, at least two engineers have to sign off on every design, and both of those engineers are held personally liable (read financially and professionally ruined) for any negligence resulting in an accident. It's a non-illustrative example.
- kurthr 9y ago
  How many bridge failures are likely to dirrectly affect people in another state or country with different laws and standards for construction without their knowledge? Which nuclear accident affected all of Europe? How many bridge failures are there per year? How many people die on average? Can you name one with greater than 150 casualties? Let me help: https://www.wikipedia.org/wiki/List_of_bridge_failures https://www.wikipedia.org/wiki/List_of_bridge_failures https://www.wikipedia.org/wiki/Chernobyl_disaster https://www.wikipedia.org/wiki/Chernobyl_disaster Now if you want to talk about tsunami, that's a different topi, but it's pretty clear why the design, review, and construction of nuclear power plants are more restrictive than even the largest and most expensive bridges (or other civil engineering projects with the possible exception of dams).
  - rdiddly 9y ago
    As I tried so hard to point out, "which accident is worse" is not the point. They are both unallowably bad. You are correct that a serious nuclear accident is likely worse than a bridge collapse. The question was how and whether mistakes in nuclear design are treated differently from other engineering fields. You brought up bridge collapses, which is a bad example because mistakes aren't tolerated in bridge design either. Or in structural engineering in general, which includes the design of nuclear plants by the way. You now bring up frequency of bridge collapses per year, which doesn't seem relevant either. Or if we somehow decide it's relevant, it's actually a counter-indicator to your point. Because if it's a low number, that means the bridge field probably takes mistakes very seriously and ferrets them out successfully. And if it's a high number, that starts to weaken your point about "which is worse." But the number would have to be pretty big to compete, and we would stop building bridges long before reaching it, and again it's not about which is worse. You finally address the point in the last line. Educate me about those design/review/construction restrictions if you like.
    - kurthr 9y ago
      I am not certain you will find the equivalent of the NRC, the IAEA, the NEPIO, or various international treaties involving most (any?) other construction projects. https://www.iaea.org/topics/construction-and-commissioning-of-nuclear-power-plants https://www.iaea.org/topics/construction-and-commissioning-o... Why wouldn't you want a random state, local, or national business design and regulate a unique nuclear power plant? What could possibly go wrong? LOL! To be clear the number of unique (because looks are important) bridge designs proliferates and the suppliers change regularly while every new nuclear reactor is a close derivative of one that has been built and tested for decades. That's not because it's the easiest or highest profit, but because international regulation and public fear are real.