I suppose I could go look this up somewhere else, but I just feel like asking here. I recall reading that the proportion of U-235 that gets removed during uranium enrichment is significantly below 100 percent. What would be an accurate number or range?

I'll try to answer my own question here.

This from the UNEP post-conflict DU report on Bosnia:

When uranium decays,another nuclide or isotope is created,which in turn is also radioactive,leading to a long chain of radionuclides (uranium daughter products)being produced (see Appendix O 'Data on Uranium').DU is roughly 40 per cent less radioactive than natural uranium and,consequently, less radiotoxic.This is because during the industrial process by which uranium ore is converted to uranium metal,uranium is chemically separated from all its daughter products beyond U-234,i.e. radium,radon and others.

      In the enrichment process used for the production of nuclear fuel,the uranium concentration of the isotope U-235 is enriched from 0.7 per cent in natural uranium to roughly 4 per cent in the uranium destined for fuel in nuclear reactors.

      The by-product is uranium with a lower concentration of U-235,i.e.depleted uranium (DU). The U-235 concentration in the DU produced is usually 0.2-0.3 per cent.In enrichment plants,U-235,which is slightly lighter in mass than U-238,is used to separate the two iso- topes,allowing the enrichment process of U-235.

     Since U-234 is an even lighter isotope,its concentration is correspondingly higher in fuel uranium and lower in DU when compared with natural uranium.The fact that DU has lower concentrations of U-235 and U-234 than natural uranium also explains why DU is less radioactive than natural uranium.Data on the specific activity of DU are given in Table 2.1.

...
The overwhelming part of the radiation emitted from the nuclides in the U-238 series is emitted from the isotopes that follow after U-234.Compared with the sum of the energy of alpha radiation emitted per transformation from all isotopes in the U-238 series,the isotopes that follow after U-234 emit about 89 per cent of the alpha energy,roughly 58 per cent of the beta radiation energy and about 98.6 per cent of the gamma radiation energy (Appendix O,Table O.4).

If reprocessed uranium from a nuclear reactor is used (fully or partially)as feed material in the enrichment process of uranium,or if this was the case during earlier runs of the technical facilities of the enrichment plant,the DU may contain tiny traces of fission products,uranium isotopes and transuranic elements that are specific to reprocessed reactor fuel.In DU penetrator material found during earlier UNEP missions to the Balkans region (UNEP,2001; UNEP,2002),traces of U-236 and Pu-239/240 could be identified.U-236 was analysed around 0.003 per cent (mass per cent),and Pu-239/240 contamination of the DU was around 20 Bq/kg (10 -2 micrograms per kilogram),which is equivalent to the very low content of one plutonium atom per 100 billion uranium atoms.This indicates that the DU found in the Balkans came into contact with reprocessed uranium at some point during its fabrication process.The concentration of contaminating nuclides is indeed so low that their contribution to the total radiation dose of DU is insignificant and can be neglected in assessing risk to humans or the environment.

This post was last modified: 08-09-2007 11:25 PM by Beagle17.

Here is a link describing in lay terms all the processes involved in uranium enrichment.

Uranium enrichment gradation scale

Regards,
Mike

http://www.umrc.net/du_and_ndu.aspx
Go here for more true info on DU and NDU.

Have more lovely doc appts at VA today; my heart looks like that of someone at least 30 years my age; DU contamination? I think so!

Will send more info and stuff when get more active again on the puter.

Hope the link above helps you and others on this forum.

Listen to Susan too, she has a lot to offer as her husband, Terry died from the effects of DU.

Tanya

I'll try to answer my own question here.

This from the UNEP post-conflict DU report on Bosnia:

    

Quote:

When uranium decays,another nuclide or isotope is created,which in turn is also radioactive,leading to a long chain of radionuclides (uranium daughter products)being produced (see Appendix O 'Data on Uranium').DU is roughly 40 per cent less radioactive than natural uranium and,consequently, less radiotoxic.This is because during the industrial process by which uranium ore is converted to uranium metal,uranium is chemically separated from all its daughter products beyond U-234,i.e. radium,radon and others.

      In the enrichment process used for the production of nuclear fuel,the uranium concentration of the isotope U-235 is enriched from 0.7 per cent in natural uranium to roughly 4 per cent in the uranium destined for fuel in nuclear reactors.

      The by-product is uranium with a lower concentration of U-235,i.e.depleted uranium (DU). The U-235 concentration in the DU produced is usually 0.2-0.3 per cent.In enrichment plants,U-235,which is slightly lighter in mass than U-238,is used to separate the two iso- topes,allowing the enrichment process of U-235.

     Since U-234 is an even lighter isotope,its concentration is correspondingly higher in fuel uranium and lower in DU when compared with natural uranium.The fact that DU has lower concentrations of U-235 and U-234 than natural uranium also explains why DU is less radioactive than natural uranium.Data on the specific activity of DU are given in Table 2.1.

...
The overwhelming part of the radiation emitted from the nuclides in the U-238 series is emitted from the isotopes that follow after U-234.Compared with the sum of the energy of alpha radiation emitted per transformation from all isotopes in the U-238 series,the isotopes that follow after U-234 emit about 89 per cent of the alpha energy,roughly 58 per cent of the beta radiation energy and about 98.6 per cent of the gamma radiation energy (Appendix O,Table O.4).

If reprocessed uranium from a nuclear reactor is used (fully or partially)as feed material in the enrichment process of uranium,or if this was the case during earlier runs of the technical facilities of the enrichment plant,the DU may contain tiny traces of fission products,uranium isotopes and transuranic elements that are specific to reprocessed reactor fuel.In DU penetrator material found during earlier UNEP missions to the Balkans region (UNEP,2001; UNEP,2002),traces of U-236 and Pu-239/240 could be identified.U-236 was analysed around 0.003 per cent (mass per cent),and Pu-239/240 contamination of the DU was around 20 Bq/kg (10 -2 micrograms per kilogram),which is equivalent to the very low content of one plutonium atom per 100 billion uranium atoms.This indicates that the DU found in the Balkans came into contact with reprocessed uranium at some point during its fabrication process.The concentration of contaminating nuclides is indeed so low that their contribution to the total radiation dose of DU is insignificant and can be neglected in assessing risk to humans or the environment.

Worked at the DOE site that produced much of the DU metal that later became tank armor and penetrators.  Most of what you have here is correct.  Keep in mind that the DU is waste material, primarily from the low end of the enrichment process (the Paducah DOE site).  Much of this DU was produced after the Paducah site began participating in a recycle loop with the Hanford DOE reactors sites, bringing low-enriched U back into the process.  This recycled material had traces of reactor build-up and fission products in it (very low, but still present).  The Paducah enrichment process naturally decontaminates this material further, but not to an absolute level.

So, the metal produced from these materials had some very small amounts of Pu, Np, Am, Tc, etc.  At these levels, the U would be the overwhelming contributor to health effects.  It would be very hard to imagine such low levels of trace contaminants overshadowing the U impacts.  Since the DOE facilities like Fernald had large stable well-studied workforces over a 50-year operating history, the health effects from U (and the inherent trace contaminants in the recycle loop) should be well-understood from the exposures that those workers had over long periods of time.  I have trouble imagining that DU munitions can be the cause of so many ailments when the same materials did not have the same effects on the workforce that made them to begin with.  There has to be more to the story.

How do the workers who handle this material dress? Do they wear suits over their clothing, do they wear some type of mask for breathing, do they wear gloves? What protective measures are they required to use when handling this?

Thank you.

Thanks for taking the time to input some good info, Cincykid.

About your comment quote above, I would expect that if DU is causing the high rates of birth defects in Iraq and/or GWS, then it is due to the fact that the DU burns into fine oxides and dust when a DU shell strikes a target (and even as it flies through the air, so they say.)

Most anti-DU activists agree that DU in a solid form is not particularly dangerous, though there is dissention on this point as well. It is the DU dust that is typically cited as the main problem.

Furthermore, there ARE reports of Paducah workers having significant problems. Let metry to find a link on that.

Again, thanks for posting your knowledge. I hope you'll come back to add things if you think they should be preserved here for others to find.