Nuclear Reactor tested

http://thespacereporter.com/2012/11/...e-exploration/

On Wednesday, November 28, 2012 8:07:48 AM UTC-7, Greg (Strider) Moore wrot
e:
http://thespacereporter.com/2012/11/...-nuclear-react
ors-for-deep-space-exploration/

I worked several years ago on a study for the now-defunct NASA Exploration
Team (NEXT) on long-range propulsion investments. Our #1 conclusion was tha
t, while there are various methods for making use of fission reactors for p
ropulsion, and we didn't know yet which approach was best, there was no esc
aping the need to have a fission system for "routine" travel within the sol
ar system. NASA at the time didn't listen to us, but this is a bit of good
news.

Matt writes:

On Wednesday, November 28, 2012 8:07:48 AM UTC-7, Greg (Strider) Moore wrot
e:
http://thespacereporter.com/2012/11/...-nuclear-react
ors-for-deep-space-exploration/

I worked several years ago on a study for the now-defunct NASA Exploration
Team (NEXT) on long-range propulsion investments. Our #1 conclusion was tha
t, while there are various methods for making use of fission reactors for p
ropulsion, and we didn't know yet which approach was best, there was no esc
aping the need to have a fission system for "routine" travel within the sol
ar system. NASA at the time didn't listen to us, but this is a bit of good
news.

The article doesn't appear to be about propulsion?

At Thu, 10 Jul 2014 18:51:58 EDT (greenaum) wrote:


I realise this is an old post, but Usenet's hardly busy these days...

Just makes me wonder, is there any known Uranium on the Moon? Or maybe
an asteroid?

The main problem with nukes in space seem to be launching them from
Earth. Obviously they wouldn't go critical (though most of the public
probably don't know that), but even then nobody fancies a ton of
radioactive dust spread through *any* layer of the atmosphere, however
high up the hypothetical launch rocket would be when it blew up.

There's the possibility of staggering launches, sending a few KG up
alongside satellites etc, maybe. That way we're only risking a small
amount each time. OTOH more launches = greater risk of exploding. The
fact that rockets still fail catastrophically at such a high rate
(compared to most other human endeavours) is a big part of it.

If rockets were more reliable, then launch worries would lessen,
though there's still the worry of having it up there, over our heads,
waiting to come back down. So you'd have to keep any nuclear fuel out
of Earth orbit, launch it as the last part of a multi-launch mission,
or a single mission that leaves Earth's gravity straight away.

But Uranium on the Moon might be an ideal solution. Nobody would mind
accidents up there, although as ever it's better to keep things tidy.

Ah, but OTOH, we wouldn't want to Moon to leave Earth's orbit... :-)
(http://www.imdb.com/title/tt0072564/)


Failing that, what about Thorium? It's seen by some as the perfect
solution for nuclear fission. Don't know a lot about it but it seems
like a wonder fuel from it's proponents, much less worry in every way.

Didn't the Soviets fly a working reactor ages ago? Steven Baxter's
novel "Titan" has it as the power-source for a mission to Saturn's
moon. Aboard a modified Space Shuttle launching on a load of Apollo
odds 'n' ends, including the Saturn V sat out on the lawn of some
museum for the last 30 years.

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On Thursday, July 10, 2014 6:51:58 PM UTC-4, greenaum wrote:
I realise this is an old post, but Usenet's hardly busy these days...


True, but this is really an old post... You could have just as well started
a new thread.



Just makes me wonder, is there any known Uranium on the Moon? Or maybe
an asteroid?


Not so much on the moon:
http://www.space.com/8644-moon-map-s...rt-supply.html

In fact compared to the Earth only areas within Copernicus crater seems to
have abundance ratios comparable to what we have in the Earth's crust. Ther
efore the mining and purification processes needed would be more complex th
an those needed to extract fission-grade Uranium here on Earth simply due t
o the fact that we are on the Moon.

http://en.wikipedia.org/wiki/Abundan...arth%27s_crust

An asteroid? Perhaps, but which one? We have so little to no survey data on
that. And even among raging optimists, anything other than a NEO would not
be practical to mine within the next decade or two.

The main problem with nukes in space seem to be launching them from
Earth. Obviously they wouldn't go critical (though most of the public
probably don't know that), but even then nobody fancies a ton of
radioactive dust spread through *any* layer of the atmosphere, however
high up the hypothetical launch rocket would be when it blew up.

Actually rocket dynamics helps a great deal. If you are not launching large
amounts of materials aka Shuttle-C fashion (i.e. directly across from your
fuel tanks) explosions aboard modern rockets would take place BELOW the pa
yload. If the payload were to be placed in a hardened "cask" there is littl
e change it would fragment. Rather it would just be pushed into a different
ballistic trajectory. Most scenarios would have the cask come down into th
e deep ocean. There are three defunct nuclear submarines I can think of tha
t are resting at the bottom of the ocean whose reactors present no threat t
o anyone on land.

There's the possibility of staggering launches, sending a few KG up
alongside satellites etc, maybe. That way we're only risking a small
amount each time. OTOH more launches = greater risk of exploding. The
fact that rockets still fail catastrophically at such a high rate
(compared to most other human endeavours) is a big part of it.

Suggest you read up on the casks used to transport highly radioactive nucle
ar waste within the US. Amazingly sturdy devices.

If rockets were more reliable, then launch worries would lessen,
though there's still the worry of having it up there, over our heads,
waiting to come back down. So you'd have to keep any nuclear fuel out
of Earth orbit, launch it as the last part of a multi-launch mission,
or a single mission that leaves Earth's gravity straight away.

I really don't understand the paranoia here. This is really irrational fear
.. Look we *already* have literally TONS of fissile nuclear material all wit
hin a 100 miles or so of major urban/suburban areas, (think Indian Point on
the Hudson in NY north of NYC, or Braidwood Station near suburban Chicago)
..

Having something in orbit that *might* present a problem 50-60 years down t
he road, assuming absolutely NO supervision in all those intervening years
is a big stretch IMHO. But unlike our nuclear power stations on Earth, the
"problem" with orbiting nuclear material is easily overcome with simple del
ta-V!

No the biggest problems to overcome are emotional/political not scientific
or engineering.

But Uranium on the Moon might be an ideal solution. Nobody would mind
accidents up there, although as ever it's better to keep things tidy.

Except that anywhere outside of Copernicus crater, it is literally non-exis
tent and at Copernicus no more abundant than here on Earth! You think minin
g and processing U on Earth is expensive? Hold on to your wallet.

Failing that, what about Thorium? It's seen by some as the perfect
solution for nuclear fission. Don't know a lot about it but it seems
like a wonder fuel from it's proponents, much less worry in every way.

IMO hardly a wonder fuel. Like all things engineering there are trade-offs.
Unlike the light-water pressurized or boiling water reactors in use in the
US, Thorium bead reactors have some advantages when used to build electric
al power stations. One is they are hard if near impossible to drive into me
ltdown. However, the reason you don't see these in widespread use in ships
and submarines is not because they were unknown at the time we began a nucl
ear navy, but because of their sheer size compared to smaller PWR/BWR react
ors of equivalent power output. Similar engineering constraints would be in
play for spacecraft applications. Space reactors, except those used solely
for propulsion, will have a lot more in common with their Naval cousins (e
sp. submarines) because of size/mass constraints than they would with elect
rical power plants.

Didn't the Soviets fly a working reactor ages ago?

You are thinking of Topaz?...

http://en.wikipedia.org/wiki/TOPAZ_nuclear_reactor

Dave