Re: New fusion power system test creates 300,000 degrees C plasma

On Sun, 01 Dec 2024 12:46:26 -0500, Joe Gwinn <joegwinn@comcast.net>
wrote:

On Sat, 30 Nov 2024 23:54:54 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:
>

On 11/30/24 22:59, john larkin wrote:

On Sat, 30 Nov 2024 21:12:23 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:
 

On 11/30/24 18:19, john larkin wrote:

On Sat, 30 Nov 2024 11:57:50 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:
>

On 11/30/24 10:34, Liz Tuddenham wrote:

Jeroen Belleman <jeroen@nospam.please> wrote:
>

On 11/29/24 23:03, Liz Tuddenham wrote:

Jeroen Belleman <jeroen@nospam.please> wrote:
>

On 11/29/24 21:04, Liz Tuddenham wrote:

Jeroen Belleman <jeroen@nospam.please> wrote:
>
[...]

It would be lovely to have 50kWTh or so of PU238 in the basement,
if it could be made cheaply enough. Power for a lifetime for the
whole house and then some.

>
...but the lifetime might not be very long if any got out.
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>

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If, if. Such arguments can be used to prove anything.
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I've got a diesel-powered car in the basement garage. Fully tanked,
it contains 60kg of fuel, good for 2.4GJ or so. Imagine the havoc
that could cause, if it got loose. For reference, a stick of dynamite
is about 1MJ.

>
I've seen what happened when builders accidentally set fire to a tank of
diesel far bigger than that.  It burned slowly and steadily until it set
fire to the roof of the house - then the house burned down.  Nobody was
injured or killed, the mess was easily cleaned up and a new house built
on the site.
>
It wasn't like the sudden release of energy you would get in a fuel-air
explosion (quite difficult to initiate with diesel without specialist
knowledge) and there wasn't a lot of residual toxic contamination.
>
>

>
OK. Now back to small 238Pu fuelled units. Why would you expect
anything to go wrong if the Pu was contained in a hermetic canister?

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There's always an idiot (or a terrorist) who would challenge themself to
open it.
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>

>
Yes, probably. There have been similar incidents in the past.
I'm convinced it can be made safe enough for widespread normal
use, but there will always be some fool somewhere. If we let
that stop us, no technology is safe enough.
>
Jeroen Belleman

>
A kilogram, properly distributed, would make a city uninhabitable for
centuries. Imagine such an active alpha emitter in a water supply.

>
There are myriad ways to create havoc, if we wanted to. I have castor
plants in the garden. They are very decorative. Properly distributed,
there is enough ricin in them to kill tens of thousands of people.
Nobody cares. Weaponizing noxious substances isn't so easy.
>

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It would make some cool glow-in-the-dark gadgets.
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Critical mass is around 10 Kg. Kids could make nukes.
>

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238Pu doesn't sustain a chain reaction, at least not in the quantities
we talk about. Nukes use 239Pu, the fissionable isotope. That's the
isotope that has a critical mass in the 10kg ballpark. Even then, it's
*very* hard to keep it together for long enough to create a sizable
explosion. No kid is going to pull that off, even if he could get his
hands on 239Pu in sufficient amounts.
>
Jeroen Belleman

 
Wiki claims
 
https://en.wikipedia.org/wiki/Plutonium-238
 
10 Kg critical mass. Are they wrong?
 

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I think so.
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Jeroen Belleman

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More sophisticated bomb design likely requires less plutonium.

Reflectors and tampers reduce critical mass, as does explosive
supercompression.

A bit of tritium in the pit helps too. I think the minimal nuke used
about 1 Kg of p239.

>
Joe Gwinn

p238 would be a terrible bomb material. Might work, though, in an
implosion bomb with a neutron injector to kick-start things.

p238 isn't "fissile", namely doesn't capture slow neutrons well.