5 ms·

Fusion reactors are trivial to operate. You just turn them on. There are no runaway scenarios related to hidden states of isotope distributions. There are no

Fusion reactors are trivial to operate. You just turn them on. There are no runaway scenarios related to hidden states of isotope distributions. There are no dangerous refueling procedures. There are many fewer necessary safety measures and no fuel waste disposal. The most expensive operating cost is hull maintenance and that can be dropped to arbitrarily low levels with R&D (swallowed by capex).

ncmncm 5y ago
The whole plant has to be taken apart at regular intervals (2 years? 1 year?), all the fiercely radioactive "blanket" plumbing and reactor wall replaced by robotic remote control (and the old stuff put where?); and the thousand tons of molten radioactive lithium/beryllium has to be continually sieved for tritium to use for fuel. If the thousand tons of molten radioactive lithium/beryllium gets loose, it it distinguishable from a fission meltdown by being worse. Ordinary beryllium oxide dust is worse than radioactives; radioactive beryllium might be worse, or only just equally bad. Molten lithium burns on contact with air and explodes on contact with water, and lithium oxide vapor turns into drain opener on contact with your nose or throat. "Hull maintenance" is I guess your name for dismantling and replacing the whole hundreds-of-tons and miles-of-pipes radioactive innards of the reactor using only R/C robots. The most reliable product of fusion promotion has always been falsehood. It seems unlikely tho change.
- willis936 5y ago
  Modular sections are pulled out and the first wall is replaced. Most of the section is put back in. You can pipeline this (like how any industrial process or digital processor works) to make the maintenance take a matter of days. The old material is low-level radioactive waste for less than a hundred years, then it's just metal. A 25 Bn USD 1 GWe plant could have 5 reactors and only need 3 to operate at max load continuously. A tritium leak is orders of magnitude less worse than a fission meltdown in terms of poisoning the water table. In the absolute worst case the exclusion zone lasts 100 years. A tritum or molten salt leak also trivial to contain compared to a fission meltdown. Ten feet of concrete. This is reflected in lower costs to build and relative ease to comply with regulation. Draw me the scenario where there is an explosion that cannot be contained by existing engineered solutions. Your most reliable product is FUD and misinformation born of confident ignorance. You really ought to stop until you know more.
  - pfdietz 5y ago
    > a matter of days Simply cooling the magnets back to operating temperature will take longer than that. ITER's coils will take a month to cool down from room temperature. The problem with leaks isn't so much that tritium is dangerous; the problem is that a leak (of coolant, or air) into the vacuum vessel destroys the ability of the fusion reactor to function at all. One of the big problems with fusion that Lidsky pointed out is they cram all this complexity into a space that's off limits to people (due to induced radioactivity). Anything breaks there, even something minor? Time consuming pain. Abdou has put up numbers on estimated MTBF and MTTR for fusion reactors that given uptimes of maybe 4%.
pfdietz 5y ago
Fusion reactors are likely to have very high operating cost, due to their complexity and the difficulty of repairing them after even minor malfunctions (because all those complex innards will be inaccessible to hands on maintenance due to induced radioactivity.) A fission reactor can operate with 2% of its fuel rods leaking. A fusion reactor will cease to operate with a single leak from a blanket module into the reactor vessel.
- willis936 5y ago
  Everything needs a risk assessment. If a reactor needs to shut down once a month for two months of maintenance that is obviously untenable. Nobody is arguing that. Bad engineering yields bad results. MCF devices need not be made by bad engineers.
  - ncmncm 5y ago
    Or, indeed, be made at all. A $30 billion reactor complex, judging by recent experience with nukes, would never be completed, but would burn $100 billion before finally being cancelled. None of the money spent would be returned, afterward.

ncmncm 5y ago

The whole plant has to be taken apart at regular intervals (2 years? 1 year?), all the fiercely radioactive "blanket" plumbing and reactor wall replaced by robotic remote control (and the old stuff put where?); and the thousand tons of molten radioactive lithium/beryllium has to be continually sieved for tritium to use for fuel. If the thousand tons of molten radioactive lithium/beryllium gets loose, it it distinguishable from a fission meltdown by being worse. Ordinary beryllium oxide dust is worse than radioactives; radioactive beryllium might be worse, or only just equally bad. Molten lithium burns on contact with air and explodes on contact with water, and lithium oxide vapor turns into drain opener on contact with your nose or throat. "Hull maintenance" is I guess your name for dismantling and replacing the whole hundreds-of-tons and miles-of-pipes radioactive innards of the reactor using only R/C robots. The most reliable product of fusion promotion has always been falsehood. It seems unlikely tho change.

willis936 5y ago
Modular sections are pulled out and the first wall is replaced. Most of the section is put back in. You can pipeline this (like how any industrial process or digital processor works) to make the maintenance take a matter of days. The old material is low-level radioactive waste for less than a hundred years, then it's just metal. A 25 Bn USD 1 GWe plant could have 5 reactors and only need 3 to operate at max load continuously. A tritium leak is orders of magnitude less worse than a fission meltdown in terms of poisoning the water table. In the absolute worst case the exclusion zone lasts 100 years. A tritum or molten salt leak also trivial to contain compared to a fission meltdown. Ten feet of concrete. This is reflected in lower costs to build and relative ease to comply with regulation. Draw me the scenario where there is an explosion that cannot be contained by existing engineered solutions. Your most reliable product is FUD and misinformation born of confident ignorance. You really ought to stop until you know more.
- pfdietz 5y ago
  > a matter of days Simply cooling the magnets back to operating temperature will take longer than that. ITER's coils will take a month to cool down from room temperature. The problem with leaks isn't so much that tritium is dangerous; the problem is that a leak (of coolant, or air) into the vacuum vessel destroys the ability of the fusion reactor to function at all. One of the big problems with fusion that Lidsky pointed out is they cram all this complexity into a space that's off limits to people (due to induced radioactivity). Anything breaks there, even something minor? Time consuming pain. Abdou has put up numbers on estimated MTBF and MTTR for fusion reactors that given uptimes of maybe 4%.

pfdietz 5y ago

Fusion reactors are likely to have very high operating cost, due to their complexity and the difficulty of repairing them after even minor malfunctions (because all those complex innards will be inaccessible to hands on maintenance due to induced radioactivity.) A fission reactor can operate with 2% of its fuel rods leaking. A fusion reactor will cease to operate with a single leak from a blanket module into the reactor vessel.

willis936 5y ago
Everything needs a risk assessment. If a reactor needs to shut down once a month for two months of maintenance that is obviously untenable. Nobody is arguing that. Bad engineering yields bad results. MCF devices need not be made by bad engineers.
- ncmncm 5y ago
  Or, indeed, be made at all. A $30 billion reactor complex, judging by recent experience with nukes, would never be completed, but would burn $100 billion before finally being cancelled. None of the money spent would be returned, afterward.