On Mon, 2009-12-28 at 04:11 -0800, Robbo wrote: > The model to be used is the population model - exponential growth > constrained by carrying capacity. We are human - we have obviously > increased the carrying capacity for ourselves a 1000 fold or more and > we are only just at the beginning of bigger, better and many more > technological advances. Thorium in fast neutron reactors would seem > to be an obvious candidate for a fuel of the coming centuries. Let’s > solve one problem at a time. Just when we should be confident - you > want to throw in the towel? > > There are billions of people now in the direst poverty. We are > nowhere near filling the universe with wheat. At any rate - economic > growth is not necessarily about physical resource inputs. It includes > medicine, education, art, poetry, music, philosophy, mathematics and > technological innovation.
So then you do agree that there are limits to growth? Limits that we will hit long before we fill the universe with wheat? Filling the universe with wheat would take about 1400 years at 3% growth. Not to mention cheap FTL transportation, converting a lot of the hydrogen and helium to carbon and assorted other improbable and/or impossible technologies. Are we not just discussing what the limits are? There is very roughly four times as much thorium as uranium. That would allow for two additional doublings, or just 48 more years at 3% growth, or two more squares on the chessboard. Ignoring little details such as waste heat. Growth isn't sustainable. There are limits to growth. Thorium could also allow for about four times the current energy usage for five billion years. Use of wind and solar energy could double or triple this again, allowing for more than eight times current energy usage for the expected life of the planet. The hard part is how do we avoid the climate disaster from burning fossil fuels (and several other potential disasters) and transition to a static resource use, static population, sustainable economy? Or do we crash, as exponential growth exceeds carrying capacity? BTW: A thorium fueled fast neutron reactor seems to me to be a very very odd choice. Thorium, unlike uranium, doesn't need fast neutrons to have a breeding ratio greater than one in a reactor. Both light water cooled and heavy water cooled reactors have been operated with thorium fuel rods, and have been shown to produce more fuel (U233) than consumed. Fast neutron reactors are more complex and expensive, but have the advantage of being able to breed more fuel (plutonium) from uranium (U238) than they consume (plutonium and U235). Why used a more expensive and complex reactor with the advantage of being able to breed fuel from uranium to breed fuel from thorium when cheaper and more reliable reactors can do that? I don't understand at all. Now, my interest in nuclear power comes from the fact that it seem to be a requirement to solve the global warming issue. I'm no expert on the details of nuclear power, so perhaps someone can point me to a discussion explaining this choice. -- Phil Hays <[email protected]> -- You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/globalchange
