Enriched Particles

The harsher tone of the International Atomic Energy Agency (IAEA) Director General Yukiya Amano’s latest report on Iran’s nuclear activities, as compared to the more diplomatic phrasing of its direct predecessor Mohamed ElBaradei has led to a lot of warmongering among America’s neocons and the Israel Lobby. Main criticism has been directed to the mentioning of old allegations regarding military dimensions of the program; Iran’s withdrawal of designated IAEA inspectors due to leakage of confidential information to the media; controversially discussed obligations of implementing additional protocols of the Nuclear Non-proliferation Treaty (NPT) and modified Code 3.1 which would have allowed early provision of design information of nuclear facilities such as the newly constructed and until mid 2009 covert uranium enrichment facility at Fordow near Qom; and finally Iran’s ongoing efforts of enriching uranium 235 to nearly 20% at the Pilot Fuel Enrichment Plant (PFEP) at Natanz, allegedly for eventually fueling the research reactor in Tehran (TRR) with higher enriched fuel plates or rods. The more than 40 years old TRR produces medical isotopes for diagnosis and treatment of, for instance, cancer.

The latter issue must be considered a contingency plan for Iran in case the fuel swap, which has been suggested in the so-called Tehran declaration of 17 May 2010 undersigned by Iran, Turkey and Brazil, would eventually fail.

One interesting piece of information in Amano’s report has not drawn much attention but was analyzed today by Joshua Pollack at ArmsControlWonk.com. The IAEA had detected particles enriched up to 7.1% uranium 235 in the vicinity of the ordinary Fuel Enrichment Plant (FEP) at Natanz.

In paragraph 7 it is mentioned that,

“7. Since February 2007, the Agency (the IAEA) has taken a large number of environmental samples at FEP, the results of which have indicated a level of enrichment of uranium of less than 5.0% U-235. In one recent result, a small number of particles from samples taken in the cascade area were found with enrichment levels of between 5.0% and 7.1% U-235, i.e. higher than stated in the Design Information Questionnaire (DIQ). The Agency, in a letter dated 13 August 2010, informed Iran of this matter and requested clarification. In letters dated 17 August 2010 and 1 September 2010, Iran provided a possible explanation for the presence of such particles, along with supporting information. Iran’s explanation is not inconsistent with the Agency’s findings.”

In a footnote to this paragraph, it is detailed that,

“In this regard, it should be noted that Iran’s explanation refers to a known technical phenomenon associated with the start-up of centrifuge cascades.”

The “known technical phenomenon” is described by Pollack today.

“After some scratching around, what turns up is a paper by Houston Wood and Stephanos Tongelidis, ‘Gas Centrifuge Cascade Study for Maximum Assays During Start-Up.’ (Not online, sorry.) As the authors explain it, when UF6 gas is fed into a cascade during start-up, it’s done slowly at first, gradually ramping up to the ‘operational’ rate:

‘During start-up of the separation process using gas centrifuges, the concentration of 235U may rise above the desired production level before coming back down at steady state conditions. As uranium feed initially enters the facility, the flow rate will increase until it reaches the design flow rate. This transient condition will produce an enrichment ‘spike’ in the gas centrifuges.’”

Pollack finds it plausible that then few particles of enriched to 7.1% may be found.

“Wood and Tongelidis develop a model of a cascade meant to produce 3-6% U-235, develop a set of scenarios, and find that ‘expected peak enrichment levels due to the time transient [are] between 8-20% 235U.’ That makes small traces of 7.1% U-235 seem comprehensible, certainly.”

But Pollack remains skeptical:

“There are more sinister explanations as well. It’s at least possible that the operators have been deliberately experimenting with higher levels of enrichment here and there, perhaps to create ‘noise’ or find out what can or cannot be detected by inspectors. This seems unlikely, though: the Iranians are already enriching to nearly 20% at the adjacent PFEP facility, so what would be the point of mucking around beyond 5% at FEP?”

I do not share Pollack’s skepticism. I am afraid that not informing the public in Amano’s report about the details of the plausible explanations provided by the Iranians does not lead to more confidence or safety but more sanctions and threats of war. Somebody should teach the major diplomat, whose reports may in fact eventually lead to peace or war, some diplomacy.

Last modified October 4, 2010.

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