Using a material flow sheet I try to address the question – how much 20% enriched uranium does Iran have and how much of it is in fuel elements? Bottom line – only about 9%. 

Chart: SV

I provide a comparison of the 20% enriched uranium produced in the six month period in Iran between the May 25th, 2012 IAEA report and the November 16, 2012 report. I have put together a simple material flow sheet of the uranium facilities and quantities to simplify the results of the IAEA November report. Bottom line: the Iran’s have produced an additional 59 kgs of 20% enriched uranium since May 2012 ostensibly for the Tehran Research Reactor Fuel elements.

The following two reports were compared: May 2012 IAEA and November 2012 IAEA report.

I prepared the chart of material flow by facility as a means of comparing the amount of material produced between May and November 2012 and their relationship to the different Iranian facilities.

This post is an update of an earlier report that covers the Tehran Research Reactor and the design of their fuel elements. 

Providing a quick overview of the increases in Iran’s enriched uranium:

  • The amount of 20% enriched UF6 increased by 87 kgs this is equal to 59 kgs of 20% enriched uranium (meaning that 20% of the uranium is enriched in U-235 a primary fissile isotope) for a total of 233 kg of 20% enriched UF6 with 157 kgs of 20% enriched uranium.
  • The increase in the amount of 20% enriched UF6 that was chemically modified to 20% enriched U3O8 was 24 kgs for a total of 38 kgs of U3O8.
  • Of the 233 kgs of 20% enriched UF6 a total of 83 kgs has been sent to the Fuel Plate Conversion Facility or 36% to convert it to U3O8 for fuel plate production for the TRR.

As described earlier the TRR fuel elements have the following characteristics:

  1. 0.28 kg of U235 per fuel element (therefore 20% enriched uranium has 20% U235 and ~80% U-238)
  2. 0.214 kg of U235 per control fuel element

Therefore calculating out the amount of U-235 and uranium in the core:

  1. 6.4 kgs of U235 in the fuel elements and control elements.
  2. 32 kgs of uranium total in the core (at 20% enriched U235).

According to the IAEA there are 10 fuel plates with 20% enriched uranium as of November at the TRR, this would account for:

  • 2.8 kgs of U235 in the fuel rods or 14 kgs of 20% enriched uranium or 16 kgs of U3O8.

Therefore of the 38 kgs of 20% enriched U3O8 available approximately 42% has been used in the production of fuel elements for the TRR.

Or conversely of the 157 kgs of 20% enriched uranium that has been produced 14 kgs has been used in the fuel or 9%.

Therefore almost 90% of the 20% enriched uranium is not in fuel elements but could be further enriched in the form of UF6 or converted from U3O8 to UF6. This is the primary concern for those worried that Iran may decide to create a nuclear weapon breakout capability using their current base of enriched uranium.

As noted earlier – the process to convert from UF6 to U3O8 was~39% efficient with 61% losses that require recovery of the material. How they recover the material and how quickly is a question that is important in determining how much UF6 is needed.

Conversely the manufacturing of a fuel element is not an easy task and requires a significant amount of testing before it can be considered qualified. With the international community choosing not to provide Iran with replacement fuel elements for the Tehran Research Reactor it provides Iran justification for the production of the 20% enriched uranium to manufacture, test, and qualify their own fuel.



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