Posted by Larry Hoover on December 27, 2016, at 0:18:55
In reply to Re: What happened? » Larry Hoover, posted by SLS on December 25, 2016, at 13:58:18
> Hi, Larry.
> I'm glad you are contributing to a movement towards safer nuclear energy.
For clarity, the Generation IV nuclear reactors have a design characteristic of being passive fail-safe. What that means is that no mechanical or human interactions are required to render the reactor safe under any adverse event.
Three Mile Island was a twice-over human failure. The staff were inadequately trained to deal with an emergency, and the equipment was inadequately maintained to respond to an emergency. When the primary water coolant system failed, the backup cooling pump was not triggered in time, and it did not work when it was finally actuated.
Chernobyl was entirely a human-caused tragedy, in that drunken staff at the two reactors "played chicken" by seeing how unstable they could make their respective reactors, until thermal changes made it impossible to exert control once more by inserting control rods to bring them back under control. The actions of the reactor staff were expressly forbidden and contrary to their training.
At Fukishima, a similar reactor to that at Three Mile Island, the back up coolant pump was diesel-powered, but located at the same level as the nuclear plant. The tsunami wave that cut the grid power to the main cooling system also swamped the backup power supply. Engineers had argued for elevating the backup generators, but accountants had argued for cost-savings by locating the generators adjacent to the plant. Another human error, IMHO.
These three reactors were Generation II reactors. The ones I'm working on are Generation IV designs. A Chinese pebble bed reactor of this engineering level has successfully passed a Loss Of Coolant Incident (LOCI). The reactor simply went to sleep when the helium gas (inert) coolant was intentionally stopped. The reactor actually performed better than the engineers expected, shutting down at a lower temperature, and more quickly than the computer models had predicted.
A commercial scale Chinese pebble bed reactor is expected to go into service in late 2017.
There are small modular versions of the pebble bed design expected to go into testing within a few years. The advantage of these new designs is that they can be installed virtually anywhere, allowing for the development of a distributed power network. Reactors will not only produce electricity, but can also produce hydrogen (fuel cells?), and heat for industrial and domestic applications.
I think that small modular nuclear reactors are the future of humankind, but that's just my opinion.