Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Pulsing an IEC 1,2,3 BANG!!!! (neutron activation)
Date: Oct 13, 1:37 pm
Poster: Richard Hull

On Oct 13, 1:37 pm, Richard Hull wrote:

>Gotta be safer than dissolving fuel slugs in nitric acid in a bucket, though..??
>I like all the news reports about how coins and jewelry at some distances (hundreds of meters) is now radioactive due to neutron activation. So much for the public geiger counter scans during the event (which WE all know don't detect neutrons)..



I didn't hear about the neutron activation bit! Hundreds of meters! Those poor bastards up close must have really gotten nuked! It takes a huge flux to neutron activate stuff! That's flux and not just neutron numbers like we use!

Either they are lying or that event lasted a lot longer than folks were told.

This is the subject of my next planned neutron counter blurb. Isotropically emitted neutrons taken as a short range flux fall off rapididly to nothing in very short distances. To rapidly and significantly neutron irradiate from a point source at 100 meters would require the mother of all fluxes!.......or a simple deadly lethal flux level sustained over many hours or days. When one considers how long it takes to activate some short lived isotopes inside the heart of a roaring reactor or pile, the reported 100 meter activations fall clearly into a "super event" disaster catagory.

Geiger counters, of course, are the only way to determine neutron activation in situ. (most iostopes giving off beta rays.)

I hope the neutron activation story didn't come from a sample of coin or jewelry taken into a lab and dropped into a sealed and shielded proportional counter which can measure vanishingly small trace levels of activation. If so, this could fall back into a small accident catagory.

Richard Hull