originally posted by: Hyperboles
that report is in error, there couldn't have been a chain reaction, they are lying, for what reason I do not know.
What does this even mean? Why couldn't there have been a chain reaction. Highly fissile material like 235Uranium, or 239Plutonium once over a certain
mass and of certain geometry will be in a state of self-sustaining chain reaction. The Demon Core shown in Arbitrageur's post was a sphere of
Plutonium designed to be 5% below the critical mass for a self sustained fission state. Materials in this close to critical mass and genometry
typically self heat because the fission process is occurring within it, and the resultant energy absorbed. That is why Plutonium is used in
Thermoelectric generators in satellites the material will constantly produce heat that can be used to power systems for a very long time.
The Demon core killed 2 people, both times caused by accidental experimental error.
The first was during neutron reflection experiments in which the core was placed into a tungston carbide castle, each piece of the reflector bringing
the core closer to being critical, due to neutrons that would otherwise be lost are then being reflected back at the core. The experimentalist dropped
one of the bricks onto the core, which was enough to compress the core and further reflect more neutrons into it causing it to enter a prompt chain
reaction until he was able to lift the brick off of it. The result being he received a fatal dose of neutrons and died 25 days later. The other person
in the room died 19 years later, receiving a far lower dose.
The second was an experiment to determine how close to critical the mass was, the core being placed in a hemisphere of beryllium (neutron reflector).
The idea is to have a second hemisphere lowered over the top of it, and count the activity using scintillator counters. Now, the actual proper
procedure was to have shims in place to prevent the two hemispheres from fully closing around the core, which would definitely make it go critical. So
the process is, lower the top hemisphere and monitor activity at each position.
The experimentalist in question had taken to performing this test not using shims to maintain separation, but the edge of a screw driver. He had done
it on many occasions, and it had been pointed out by many that one mistake would cause his death... non the less he thought he knew better and it
wouldn't happen to him... on that day, the screw driver blade slipped and the hemispheres were allowed to close, causing the core to go critical. He
described how he saw a flash of blue light in his eyes, and feel heat instantly over his skin, attributed to large burst of neutrons which are readily
thermalized in water. To prevent a sustained reaction he was able to flip the top hemisphere off of the core. He however was a dead man walking,
getting 5 times the dose the first victim of the core, and died 9 days after the incident. Other people present that day were tracked, all dying many
years later, but many of the deaths attributed to radiation related complications and illnesses
So now that it is all spelt out in detail how the experiments and accidents occurred... tell me, how do you get a fatal dose of neutrons out of a
piece of material without it going critical or entering a state where a chain reaction briefly occurs?
why use a detonator then in the weapons. super critical or otherwise if you get a chain reaction from some lousy bricks.
Your flippant and arrogant dismissal shows how little you understand nuclear technology and the control of run away conditions. When a mass like this
goes critical, it doesn't instantly explode. If you think it does then you are very sadly mistaken. Surrounding a core with shielding would make it
energy a super critical state and begin to produce large amounts of radiation and heat. There is a lag time between the initial critical state and the
chain reaction entering an explosive state. The heat can cause physical and geometric changes in the material which can do three things... either
prevent the core going into a explosive state, dropping it sub critical, melt the core or enter an explosive state. Typically you'd not want to melt
the core as that is quite dangerous and tends toward the explosive state.
To get such a system to explode you need to hold the core in a super critical state, well over its critical point and maintain that critical mass.
THEN it will explode, the chain reaction rapidly accelerating and producing heat and radiation contained within the device. In that state the energy
density becomes so high that an explosion from the rapid expansion and liquefaction and vaporization of the device become inevitable simply from the
amount of highly penetrating radiation being produced.
So the point of having a detonation mechanism is for safety.... there is a very good reason while modern high explosives are somewhat 'safe' these
days... because too many people died using unstable materials in which mishandling can cause them to go off. Nitrate based blasting material in mines
for example, are actually not that explosive in their normal state. Its with the addition of a blasting cap or energy delivery device which makes them
explode. Until then, even tossing a cigarette on them doesn't have a huge probability to cause an explosion (id still not recommend it though, just in
case) It is such if you are designing a nuclear device, you wouldn't want it so dangerously close to critical in a standby configuration. You would
also want the core of it to be able to go critical very rapidly upon triggering. It is such that a typical device works on either gun type combination
of the core material to a single super critical mass... or a configuration in which you melt and compress the core using high explosives to produce
Clear? So exactly why make a statement demonstrating your ultimate lack of ability to comprehend any nuclear technology as to try and demonstrate you
know better than everyone in the world?
pendulum and others: all physical processes pertaining to time keeping/ flow have to tally with one another. there can be no contradiction. I hope
understanding of all above comes to you, if you get your head out of the sand
a reply to: Arbitrageur
A Pendulum is a composite mechanical object and its very operation is driven by the acceleration due to gravity... not the bending of space time
directly. As we already discussed at exacerbating length... because a pendulum wont swing when placed at a lagrange point, does in no way mean time
stops there. To claim that a pendulum clock is = to an atomic clock is to show supreme ignorance.
edit on 14-5-2019 by ErosA433 because: (no reason given)
edit on 14-5-2019 by ErosA433 because: (no reason given)