221–230 of 373 posts
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Make an efficient fusion reactor the size of a truck, and the solar system becomes your backyard.
Make an efficient fusion reactor of any size, and you can power Fischer-Tropsch plants to synthesize carbon-neutral hydrocarbon fuel for the existing fossil-fuel infrastructure.
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Speaking pedantically, the next decade actually starts 1-Jan-2021.
This is not even pedantically correct. I quote ISO/WD 8601-2: Representation of a decade must be exactly three digits, leading zeros, if any, must be included. Thus the time interval 200 through 209 is represented as ‘020’ and NOT ‘20’; the latter would represent the time interval 2000 through 2099. Here you can clearly see that the ISO definition of a decade is in keeping with the common understanding, not whatever…
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Deuterium is a stable isotope, but Tritium’s half life is only 12.32 years making it quite radioactive. There is significant effort put into using lithium blankets to create tritium at which point arguably the fuels are lithium and deuterium. But that’s also going to require irradiate the relevant equipment.
Tritium is worth $30,000 a gram.
At scale it’s significantly cheaper to produce.
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You're correct, that's a good ballpark for the average heat generation rate in the sun. However, 99% of heat generation in the sun occurs in the core (approximately the center 25% by radius) and this area is much more energy dense. Further, fusion reactors could achieve an even higher volumetric heat generation rate then the sun's core does. To collect energy, heat would be transferred to a working fluid (e.g., molte…
There's something that feels so archaic about using a nuclear reactor to... boil water and spin a turbine. It's disappointing that we haven't figured out a better way to convert to electrical energy than what we were using in the 1800s.
Inducing a current by moving something in a magnetic field, or vice versa, may seem like simple designs, but perhaps that's why we haven't replaced them yet. Rotational motion seems easy to service and efficient.
Same with water being particularly easy to turn into a gas using heat, as well as being super plentiful on Earth. There are just a lot of things going for a steam turbine
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I’m also a layperson and also a fan of the 7-X, almost on purely aesthetic grounds. The plasma shape is a beautiful twisted loop, the magnets resemble a French crueler, and with the shielding and instrumentation it has all the charm of a steampunk time machine
As a layperson, this design seems far too complex to be useful for fast iterative research and ultimately, economic replication. It reminds me of the principle that one shouldn't start a space travel project that is estimated to take more than x years to complete, because by that time, technological progress will have surpassed its speed and capabilities, and would physically overtake it (the 'wait calculation').
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"Non Radioactive Fuel" is technically correct. But. The fusion produces neutrons.[1] That means that at least some parts of the infrastructure can't avoid becoming radioactive. Decommissioning -- at the very least -- is still a problem. Any actual nuclear physicists want to chime in here? [1]Yes, the concept of "Aneutronic fusion" exists: https://en.wikipedia.org/wiki/Aneutronic_fusion >. But read the parts about the…
Deuterium is a stable isotope, but Tritium’s half life is only 12.32 years making it quite radioactive. There is significant effort put into using lithium blankets to create tritium at which point arguably the fuels are lithium and deuterium. But that’s also going to require irradiate the relevant equipment.
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Continuing the pedantalization escalation the 21st century started 2001-01-01 if you follow the Gregorian calendar "named after Pope Gregory XIII, who introduced it in October 1582" However if you are not fussed about pope Greg and then and go with ISO 8601 or common usage it started 2000-01-01.
And the transition from Julian to Gregorian just changed the leap year rules. It didn't change the fact that there's no year 0. The 1st Century began in the year 1. I don't believe anything in ISO 8601 refers to the century starting 2000-01-01 as "the 21st century" (though apparently it does, in some contexts, allow "20" to refer to the century that started on that date). The century called "the 1900s" overlaps with…
It is not issue of Julian vs Gregorian date, but the issue that ISO 8601 uses different conventions. Traditionally, there were two disjoint timelines (AD/CE and BC/BCE), both starting at year 1. Within these conventions, it make sense that first century is 1-100 CE, second century 101-200 CE and so on.
ISO 8601 instead uses astronomical year numbering ( https://en.wikipedia.org/wiki/Astronomical_year_numbering ), which has signed integer year numbers including year 0. Therefore, there is no beginning of timeline and most natural way how to define centuries by div 100, e.g. years 0-99 is century 0, and so on.
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That's a version of "The Wait Calculation". For instance, it would be a waste of resources to build a starship right now to visit the closest other solar systems, because given our current maximum velocity and our rate of technological increase, it's a virtual certainty that in the future we would be able to build a second starship that would catch up and overtake it. Eventually there is a break even point (for the c…
This is a great mental model. I'm curious about applying this in areas of one's own life. Certain things that you'd actually accomplish faster, by starting later and leveraging the compounded time / resources that would have been spent pursuing it earlier.