Fine. I was using action while you are using state, but we can use enriching for clarity to reduce confusion. The point is the same.
Not so fast with the dictionary. I didn't stop with the noun/verb issue. That would have been pedantic. I also provided, from the same reference that you are using, evidence that enrichment is also used to refer to the degree of the enrichment of fissile material and not merely as the name of the process or state.
What did you think the wikipedia article meant when it referred to an enrichment of 80 percent? Is it your opinion that such usage is incorrect?
That does not mean that you have worked through the question of what you need to do to increase the rate of decay, and then determined how that affects the rest of the (atomic) world.
Are you claiming to have done so? I'm going to return to this question at the end. I'll just note here that I don't see that you have actually made an argument that addresses this point. Instead you have asserted effects that result directly from an increased fission rate. And some of those assertions are demonstrably wrong. I'll deal with those first.
I am in fact familiar with the factors that are required to allow a sustained chain reaction, and your posts suggest that you are not. Increasing the number of source neutrons alone without increasing the percentage of those neutrons that cause fission will not result in criticality. In fact the lack of a suitable source of neutrons for starting a chain reaction is a problem that we dealt with occasionally when the submarine's reactor had been shut down for a considerable period.
Curiously, the natural reactors at Oklo were started by spontaneous fission.
Started, yes. I've already acknowledged that some source of neutrons is required to start the chain reaction and that neutrons from spontaneous fission are candidates for doing so.
But the starting of the Oklo reactor required something more than a ource of neutrons. Some action must have occurred such as adding a water moderator, or concentrating the uranium, or changing the shape of the "vessel" in which the uranium is contained. In other words by some change that actually affected keff so that it became > 1. The wikipedia article describes some possible scenarios.
Your argument regarding the natural state of enrichment does not rebut my argument in any way. Nor does the observation that natural reactors can no longer occur. As your source indicates, the reason that they can no longer occur is because of the ever decreasing amount of U235 relative to U238. That point is completely consistent with my argument as well as yours. But other factors suggest that I am correct.
It does not double the number of targets, but it does double the number of bullets, thus doubling the exposure of the targets, with the effect being the same as doubling the enrichment in material today. This would also be akin to providing a neutron reflector around the material.
I'll make two points regarding the above
First, increasing spontaneous fission is not akin to providing a reflector. A reflector allows some of those neutrons that escape the mass of uranium to have a second chance at creating fission. Increasing the number of source neutrons alone does not increase the chance that any one of those neutrons induces fission.
Further, simply increasing the generation rate of source neutrons won't
decrease the percentage of neutrons that get absorbed in materials other than uranium, and would not necessarily decrease the
percentage of neutrons that escape the mass of uranium.
Secondly, you are ignoring half of the argument that I made. Increasing enrichment increases both bullets and targets, while increasing the decay rate simply increases the bullets. I think it should be quite obvious that those two situations do not produce the same result. That should at least open up the possibility that increasing enrichment will increase keff (see six factor formula) while increasing the decay rate might not.
But let's address your questioning of whether I have considered what other reactions might increase if the decay rate is increased. I think this is a valid point.
The mechanism for increasing the decay rate has not been specified. At this point the mechanism is PFM (pure freaking magic). I think it is reasonable (but perhaps not inevitable) that the mechanism will increase spontaneous fission in the same way it increases U238 decay rates, exactly as you have proposed, and I have assumed that such a thing will happen.
But I don't think it is reasonable that the same PFM would inevitably change things such as the relative rates of absorption of neutrons in uranium vs. other materials, the rate at which neutrons are slowed down by a moderator such as water, or the probability that a neutron in the vicinity of a U235 atom actually gets absorbed. So absent a mechanism, I don't see how you can conclude that increasing the decay rate will inevitably produce a critical geometry.
I think our disagreement results from your belief that enrichment enables criticality by increasing the number of spontaneously generated neutrons. My position is that enrichment enables criticality primarily by increasing the number of targets available for each generated neutron.
Edited by NoNukes, : No reason given.
Under a government which imprisons any unjustly, the true place for a just man is also in prison. The proper place to-day, the only place which Massachusetts has provided for her freer and less desponding spirits, is in her prisons, to be put out and locked out of the State by her own act, as they have already put themselves out by their principles. Thoreau: Civil Disobedience (1846)
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