[ RadSafe ] Space travel, reactor enrichment

[JPreisig at aol.com]

Hey Radsafe:
 
       Yeah, cost of going to Mars using a  reactor is going to be high.  
Reactor using Enriched
Uranium is dimensionally not all that large --- See Nerva, Prometheus and  
all that.  The rest of the spaceship
could be considerable in size.
 
       Launch of reactor space ship from  Earth is apparently another 
problem.  See some of my 
emails in Radsafe Archive dealing with this problem.  Basically, one  
builds the reactor spaceship
from modular parts up at the International Space station.  The modular  
parts would be transported to
the ISS via chemical rockets.  Then assemble the reactor  /spaceship.
 
      Then turn the reactor on, load up the space  crew and supplies and 
head to Mars or wherever.
 
      Once at Mars, the reactor spaceship is  placed in orbit around Mars.  
A type of Lunar Landing
Module would be used to get to and from Mars.  Collect samples etc. on  the 
surface of Mars.
 
      Return to the ISS.  Tether the  reactor/space ship to the ISS (or 
somewhere else) and 
let the crew return to Earth via the Space Shuttle II or some other  
spacecraft or rocket system.
 
      Sure, it's expensive.  NASA needs to  work on something besides just 
launching satellites.
 
      I need to do more calculations about launch  from Earth before I will 
fully concede that a
reactor/spaceship cannot launch itself from the surface of the Earth.
 
      Have a good  weekend...     Regards,  Joseph R. (Joe) Preisig,  PhD
 
 
 
 
In a message dated 8/5/2011 2:25:42 P.M. Eastern Daylight Time,  
Mike.Brennan at DOH.WA.GOV writes:

At the  moment, and for the foreseeable future, the cost of getting a
package out  of the Earth's gravity well is going to be higher than
something like  enriching uranium.  I personally have given a lot of
thought to how  one can design a reactor for use on a space ship (I write
science fiction),  and it is a non-trivial problem.  It is hard to run a
reactor that  doesn't have a permanent "down" to produce density
gradients.   

As for launching an "atomic rocket" from the Earth; I haven't  seen
anything that makes me believe anyone has figured out how to get  that
much acceleration our of heating reaction mass with a reactor.   But I
acknowledge to not knowing nearly everything.  

I, for  one, would not care to have to decon the launch site, however.  

-----Original Message-----
From:  radsafe-bounces at health.phys.iit.edu
[mailto:radsafe-bounces at health.phys.iit.edu]  On Behalf Of
JPreisig at aol.com
Sent: Friday, August 05, 2011 10:59  AM
To: radsafe at health.phys.iit.edu
Subject: [ RadSafe ] Space travel,  reactor enrichment

Hey Radsafe,

Hmmmmm.  Whether one uses sodium  or some other material in the  
primary loop of a reactor
on a space ship, one can use fast neutron  fission to possibly avoid
using  
highly enriched
Uranium (or  whatever) as a fuel.  Just use the usual 5% or whatever  
reactor  grade enrichment in
U235.  Hmmmmm, sounds much less expensive than  using 95% enriched
Uranium.

Guess the  mainland Chinese will have a  spaceship, based on all 
this, off the  ground soon
(using technology the USA and other countries  developed!!!!).

Have a good   weekend!!!!      Regards,    Joseph R.   (Joe)
Preisig,  
PhD




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