Nuclear Power Forum Main Message Replies

The current date and time is:

Original Main Message:

f chemisty (Click here to reply)
Thu Oct 21 16:02:23 EDT 1999 , jess
Where did the original nuetron come from that starts theNuclear Fission Chain Reaction?
Posted from out200-46.sdcoe.k12.ca.us.

Replies:

1 (Click here to reply) Sun Jan 2 15:01:09 EST 2000 , Karl Johanson (karljohanson@home.com)

On Thu Oct 21 16:02:23 EDT 1999, jess said:
>Where did the original nuetron come from that starts theNuclear Fission Chain Reaction?

An excellent question. When uranium 235 decays it usually produces alpha particles ("wavicles" to be more precise). Very rarely uranium produces a neutron due to decay. These very few neutrons are enough to get an atomic pile to begin fissioning. In nature the number of neutrons produced is low and the concentration of uranium in the ground is low as well. This adds up to an extremely low rate of neutron induce fission in nature. (This wasn't always true. In the past the percentage of U235 in natural uranium was much higher. Natural nuclear reactors at Gabon Africa went critical for around half a million years when ground water moved through uranium deposites and acted as natural neutron moderators. Good news from these reactors is that the plutonium produced barely migrated through the rock it was formed in (as evidenced by it's decay products) even though boiling water flowed over it for half a million years (more than 20 times the half life of plutoniunm 239). A web search on "nuclear" and "Gabon Africa" should find many interesting sites on this.)

Nuclear weapons require very high initial amounts of neutrons compare to nuclear reactors. They use a radio-isotope which produces neutrons as an "initiator" to start the chain reactions of fission in the weapon.
_

f	chemisty (Click here to reply)	Thu Oct 21 16:02:23 EDT 1999 , jess
	Where did the original nuetron come from that starts theNuclear Fission Chain Reaction?
	Posted from out200-46.sdcoe.k12.ca.us.

1	(Click here to reply)	Sun Jan 2 15:01:09 EST 2000 , Karl Johanson (karljohanson@home.com)
	On Thu Oct 21 16:02:23 EDT 1999, jess said: >Where did the original nuetron come from that starts theNuclear Fission Chain Reaction? An excellent question. When uranium 235 decays it usually produces alpha particles ("wavicles" to be more precise). Very rarely uranium produces a neutron due to decay. These very few neutrons are enough to get an atomic pile to begin fissioning. In nature the number of neutrons produced is low and the concentration of uranium in the ground is low as well. This adds up to an extremely low rate of neutron induce fission in nature. (This wasn't always true. In the past the percentage of U235 in natural uranium was much higher. Natural nuclear reactors at Gabon Africa went critical for around half a million years when ground water moved through uranium deposites and acted as natural neutron moderators. Good news from these reactors is that the plutonium produced barely migrated through the rock it was formed in (as evidenced by it's decay products) even though boiling water flowed over it for half a million years (more than 20 times the half life of plutoniunm 239). A web search on "nuclear" and "Gabon Africa" should find many interesting sites on this.) Nuclear weapons require very high initial amounts of neutrons compare to nuclear reactors. They use a radio-isotope which produces neutrons as an "initiator" to start the chain reactions of fission in the weapon.
	_