3 ms·

First, the costs of nuclear power are quite substantial AND they are front-loaded making it a bad investment. You will need to go through a lot of red tape and

by iopq 4y ago

First, the costs of nuclear power are quite substantial AND they are front-loaded making it a bad investment. You will need to go through a lot of red tape and spend all the money right away to get some benefit later when it's built. Second, it's not zero carbon if you include building the plants, since the plants have a limited lifespan, so there's still a carbon footprint for the materials. Third, if you switch all of our energy to nuclear today with a magic switch, we would run out of all easy to mine uranium in a few decades. While that is not a concern in our lifetimes, some progress on thorium plants and so forth must be made for nuclear to be a long term solution.

ekianjo 4y ago
> Second, it's not zero carbon if you include building the plants, since the plants have a limited lifespan, so there's still a carbon footprint for the materials. Nothing is zero carbon either. Batteries have a very long supply chain that involves a lot of carbon heavy steps, and their disposal also creates pollution. The same goes for solar panels, but people conveniently choose to ignore that. > we would run out of all easy to mine uranium in a few decades We dont need uranium to run on nuclear power. There are several alternatives already.
ETH_start 4y ago
>>Third, if you switch all of our energy to nuclear today with a magic switch, we would run out of all easy to mine uranium in a few decades. There are vast quantities of uranium in ocean water in concentrations that while low, still allow it to be extracted. More importantly, breeder reactors can harvest 100X more energy from uranium than currently deployed reactor types, and in the process eliminate all of the long-lasting nuclear waste, i.e. those with a half life of millions/billions of years. With known supplies of uranium and thorium on Earth, nuclear fission can provide 100% of humanity's current energy needs for something like 2 billion years. For reference, the sun's rising luminosity is expected to boil Earth's oceans away in 900 million years. We could 1000X current energy consumption with nuclear, and have enough fuel on Earth for over a million years. Long before the fuel runs out, we will be able to exploit resources beyond Earth.
- pfdietz 4y ago
  All those options are significantly more expensive than what we've been building. I mean, we've built fast reactors, and thermal breeders with thorium, and had pilot efforts for U extraction from sea water. None of them could compete with LWRs with a once-through fuel cycle on conventionally mined uranium. Fast reactors also present the possibility of prompt fast criticality (that is, an actual nuclear explosion) in a serious accident if enough of the core melts and moves around.
  - ETH_start 4y ago
    Thanks for the sobering information. In any case, costs can be brought down significantly with 1. more reasonable regulations and 2. economies of scale, which just requires building more plants. So if - due to massive expansion of nuclear power - we get to the point that uranium supplies are dwindling and causing the price of uranium ore to rise, we may still see breeder reactors with lower construction and operating costs than current generation reactors. I suspect modularity in reactors, that enables a genuine global market to emerge in reactor manufacturing, would be instrumental in bringing down reactor construction costs. >>Fast reactors also present the possibility of prompt fast criticality I'm quite the layman in this subject, but my understanding is that there are fourth generation fast reactor models, with passive safety features, that effectively eliminate that possibility.
    - pfdietz 4y ago
      The claims that costs can be brought down with better regulations and economies of scale are often made, but the evidence for that is marginal. For regulations: how does one identify "reasonable" regulations? How is this to be determined? The usual way this is done in other industries is by allowing accidents to happen, then add regulations that would have prevented them. I doubt that would be acceptable for nuclear: unlike (say) aviation accidents, the cost of an individual accident can be extremely large. As for economies of scale, the evidence for that in nuclear is slight. Maybe S. Korea? But elsewhere costs seem to have increased with experience rather than decreasing. Nuclear involves large units that take a long time to build; there's not much room for anyone to gain much experience over their career. If anything, experience decay (as organizations and individuals age) seems to overwhelm experience growth. > fast reactors Fast reactors inherently have this problem, since a fast chain reaction occurs without a moderator. In a LWR, concentration of the fuel in an accident reduces reactivity, as the moderator is reduced. In a fast chain reaction, concentration of the fuel will increase reactivity. Putatively safe 4th generation reactors merely assert that such rearrangement cannot happen. If the analysis that led to that conclusion is found to be in error then anyone who has built such a reactor will be in deep trouble. Perhaps molten salt fast reactors will have sufficiently credible analysis, but those have their own issues (such as need for large amounts of isotopically separated chlorine in molten chloride reactors and exposure of the walls of the reactor to unshielded/unmoderated fast neutrons.)

by iopq 4y ago

ekianjo 4y ago

> Second, it's not zero carbon if you include building the plants, since the plants have a limited lifespan, so there's still a carbon footprint for the materials. Nothing is zero carbon either. Batteries have a very long supply chain that involves a lot of carbon heavy steps, and their disposal also creates pollution. The same goes for solar panels, but people conveniently choose to ignore that. > we would run out of all easy to mine uranium in a few decades We dont need uranium to run on nuclear power. There are several alternatives already.

ETH_start 4y ago

>>Third, if you switch all of our energy to nuclear today with a magic switch, we would run out of all easy to mine uranium in a few decades. There are vast quantities of uranium in ocean water in concentrations that while low, still allow it to be extracted. More importantly, breeder reactors can harvest 100X more energy from uranium than currently deployed reactor types, and in the process eliminate all of the long-lasting nuclear waste, i.e. those with a half life of millions/billions of years. With known supplies of uranium and thorium on Earth, nuclear fission can provide 100% of humanity's current energy needs for something like 2 billion years. For reference, the sun's rising luminosity is expected to boil Earth's oceans away in 900 million years. We could 1000X current energy consumption with nuclear, and have enough fuel on Earth for over a million years. Long before the fuel runs out, we will be able to exploit resources beyond Earth.

pfdietz 4y ago
All those options are significantly more expensive than what we've been building. I mean, we've built fast reactors, and thermal breeders with thorium, and had pilot efforts for U extraction from sea water. None of them could compete with LWRs with a once-through fuel cycle on conventionally mined uranium. Fast reactors also present the possibility of prompt fast criticality (that is, an actual nuclear explosion) in a serious accident if enough of the core melts and moves around.
- ETH_start 4y ago
  Thanks for the sobering information. In any case, costs can be brought down significantly with 1. more reasonable regulations and 2. economies of scale, which just requires building more plants. So if - due to massive expansion of nuclear power - we get to the point that uranium supplies are dwindling and causing the price of uranium ore to rise, we may still see breeder reactors with lower construction and operating costs than current generation reactors. I suspect modularity in reactors, that enables a genuine global market to emerge in reactor manufacturing, would be instrumental in bringing down reactor construction costs. >>Fast reactors also present the possibility of prompt fast criticality I'm quite the layman in this subject, but my understanding is that there are fourth generation fast reactor models, with passive safety features, that effectively eliminate that possibility.
  - pfdietz 4y ago
    The claims that costs can be brought down with better regulations and economies of scale are often made, but the evidence for that is marginal. For regulations: how does one identify "reasonable" regulations? How is this to be determined? The usual way this is done in other industries is by allowing accidents to happen, then add regulations that would have prevented them. I doubt that would be acceptable for nuclear: unlike (say) aviation accidents, the cost of an individual accident can be extremely large. As for economies of scale, the evidence for that in nuclear is slight. Maybe S. Korea? But elsewhere costs seem to have increased with experience rather than decreasing. Nuclear involves large units that take a long time to build; there's not much room for anyone to gain much experience over their career. If anything, experience decay (as organizations and individuals age) seems to overwhelm experience growth. > fast reactors Fast reactors inherently have this problem, since a fast chain reaction occurs without a moderator. In a LWR, concentration of the fuel in an accident reduces reactivity, as the moderator is reduced. In a fast chain reaction, concentration of the fuel will increase reactivity. Putatively safe 4th generation reactors merely assert that such rearrangement cannot happen. If the analysis that led to that conclusion is found to be in error then anyone who has built such a reactor will be in deep trouble. Perhaps molten salt fast reactors will have sufficiently credible analysis, but those have their own issues (such as need for large amounts of isotopically separated chlorine in molten chloride reactors and exposure of the walls of the reactor to unshielded/unmoderated fast neutrons.)