[ExI] cost of SBSP and thorium

[Keith Henson]

On Sat, Aug 18, 2012 at 5:00 AM,  John Clark <johnkclark at gmail.com> wrote:
>
> On Fri, Aug 17 Keith Henson <hkeithhenson at gmail.com> wrote:
>
>> there are no thorium power reactors
>
> Today that is true but if this was before1969 it would not be.
>
>> in spite of places like India having a lot of it and needed energy badly.
>>  Why?
>>
> That's the only substantial criticism I get, if it's such a great idea why
> aren't we doing it?  I could ask you the same thing about power satellites.

I told you why.  Until early this year nobody had an idea of how to
get the transportation down cheap enough for power satellites to make
sense economically.

snip

"The People’s Republic of China has initiated a research and
development project in thorium molten-salt breeder reactor
technology.[100] It was formally announced at the Chinese Academy of
Sciences  (CAS) annual conference in January 2011. Its ultimate target
is to investigate and develop a thorium based molten salt breeder
nuclear system in about 20 years."

*If* power sats were to be developed on the most economical schedule,
it calls for enough of them 20 years after the start to get humanity
off fossil fuels.

>> Going from none to 30,000 one GW thorium burners is as much of a boggle
>> factor going from none to 30 TW
>> of power sats.
>
> A Thorium reactor has produced 7.4 megawatts of power for several years,
> and it used technology that was over 40 years old; but even with today's
> technology a power satellite has not managed to produced one watt for one
> second.

And they never will produce one watt for one second.  If they are
built at all, they have to produce hundreds of GW or there is no
reason whatsoever to build them.

I might add that nuclear reactors, U or Th are (in my opinion) the
next best choice for supplying TWs of power to replace fossil fuel.
If you read David MacKay's book, nothing else scales into the amount
of power we need.

However, the time scale involved (which I don't understand at all)
makes them a questionably choice.  Any thoughts on why even the
Chinese think it will take 20 years?

Keith