reactor core signature

[wlrun3@aol.com]

   ...i thought that each core load had a unique isotopic mix which could serve as a fingerprint much in the way that each nuclide has a unique decay constant and, with gamma spectroscopy, a unique gamma energy profile...

   ...if i am right, do the fuel vendors and the reactor engineers have these numbers...

   ...could i readily identify the core that originated contamination found uncontrolled out in the general population...

   ...can i tell by body count which core an intake came from...

   ...in the movie "Sum of All Fears" the nuclear weapon that destroyed baltimore is identified from the debris as originating from "K reactor, Savannah River, February, 1968"...

   ...is this realistic and, if so, can it be done for power reactor nuclides...

[G-reg]

I can't answer your first two questions, but the answer to all of the subsequent questions is "No".

Inside of a fuel pin, it may be at least theoretically possible (given enough raw data and an immense amount of number-crunching) to back-track a specific composition all the way to its origin.  I sure as hell couldn't do it...   

But once you get outside of the fuel pins, all bets are off.  No way, no how.  Reason being that no one plant itself (again, outside of the fuel pins) is iso-isotopic.  A smear taken inside a S/G bowl isn't going to have the same chemical or isotopic composition as a smear from inside the PZR, and neither of those is going to match a smear from the cavity.  And just to throw more variability into it, suppose the worker got his/her uptake while changing out a vacuum cleaner filter?

(But it certainly does make for some good sci-fi!   )

- Greg

[namlive]

Perhaps I shouldn't say anything, but I have seen spent fuel sampled to get a fingerprint should that material ever be used for a dirty bomb.
I don't believe each core has its own isotopic signature as much as each fuel design or mixture having its own signature.

[Marlin]

Since every reactor produces spent fuel with a unique "fingerprint" of small variations in isotopic concentrations, similar analyses could help investigators determine the source of material for a terrorist bomb.

http://www.nytimes.com/2009/03/03/science/03plut.html?_r=1&ref=science

http://nsspi.tamu.edu/project_det/index.php?project=3

[namlive]

Since every reactor produces spent fuel with a unique "fingerprint" of small variations in isotopic concentrations, similar analyses could help investigators determine the source of material for a terrorist bomb.

http://www.nytimes.com/2009/03/03/science/03plut.html?_r=1&ref=science

http://nsspi.tamu.edu/project_det/index.php?project=3

Interesting. Each reactor or fuel cycle produces a unique signature based on its power history. The forensic question would be, "How much difference is there in the isotopic mixture as compared to the accuracy of the analysis?"

Of course like everything else, if the fingerprint isn't on file... Not a lot of nuclear facilities are giving up pieces of their spent fuel to Uncle Sam to be fingerprinted, nor would the guilty party be likely to do so should a dirty bomb go off.

First, someone would of had to retreive spent fuel in order to make the bomb. Just go over to that spent fuel pool, pull out a few racks, stuff them under your jacket, and try to act natural walking out. For some reason, I don't see much of this happening. It would be easier to crash an airplane filled with jet fuel into the tin roof of a spent fuel pool.

[Marlin]

First, someone would of had to retreive spent fuel in order to make the bomb. Just go over to that spent fuel pool, pull out a few racks, stuff them under your jacket, and try to act natural walking out. For some reason, I don't see much of this happening. It would be easier to crash an airplane filled with jet fuel into the tin roof of a spent fuel pool.

Sampling and analyzing the fuel/product can be done easily, stealing it is another issue.

[retired nuke]

Hmmmm, I looked at it as a future lawsuit tracking down owners of waste for cleanup...legacy stuff....

[Marlin]

On Topic

Having spent many years working with commercial waste processing facilities and I've seen an endless variety of isotopic mixes for waste streams from each plant.  I'd imagine that any of you who do the sampling which serves as the basis for your 10CFR61 data are fully aware of the considerable variation in isotopic mixes throughout your plant and over time.  Combine that with variation in how different isotopes would distribute themselves during the bomb event and the uncertainty is unmanageable.  Isotopic fingerprints are pure Hollywood OR maybe stuff shovelled by a sales guy trying to get a government contract [neither of which is a very reliable source for technical information]. 

So you have recieved and sampled spent fuel?

From my link above:

Summary:A method for unique identification of spent nuclear fuel has been developed in order to enhance transparency in international safeguards. The method relies on distinguishable differences in fission product concentrations produced in the spent fuel as a result of variations reactor power history.

[Duke Nuker]

On Topic

Off Topic

On related note, what's the deal with the whole "dirty bomb" scenario anyway?  The whole idea of a bomb is to explode, and explosions spread stuff all over the place [
My apologies for the tangent, but I was wondering if anyone else was perplexed by the validity of the dirty bomb threat as I've been?

mgm

The idea is not to overexpose, it is to create panic by having a widespread radioactive material release.  Who cares about the actual exposure? (remember your history)  It is the tought of "radioactivity" being spread that is the attention getter.  A dirty bomb is not intended to overexpose anyone. It is a threat to the masses because they only know what the media has told them - Radiation = Very bad - in any amount.

[G-reg]

True.  I doubt that many individuals in the general public could draw any meaningful distinctions between Chernobyl, Three Mile Island, a dirty bomb, and "The China Syndrome".

To the general public at large, all of the above items are one homogeneous entity in their eyes.

To those "in the know", the most serious effect from a dirty bomb is a potentially lethal exposure to public fear and ignorance.

[namlive]

So you have recieved and sampled spent fuel?

I have been involved. The spent fuel is loaded into a PVC container and then into  an 8 ton cask underwater. It is then transported to a lab facility where the cask is unloaded into a shileded cell, where it is removed and sampled. (More complicated than I mention, but that is the meat of it.)

[peteshonkwiler]

To those "in the know", the most serious effect from a dirty bomb is a potentially lethal exposure to public fear and ignorance.

I'd say "ignorance" is the most serious effect to be expected and suffered.