Regular readers know that Iran’s uranium conversion facility (UCF) at Esfahan (Isfahan) stinks—a fact Paul first reported in the October 2004 edition of Arms Control Today and which forms the basis for IC judgements about Iran’s proximity to a nuclear weapons capability.

Nuclear Fuel and Reuters (hat tip SQ and GSN) have written four articles in the last month detailing problems with the UCF. Francois Murphy and Louis Charbonneau with Reuters have the best quote:

“The UF6 is crap,” said a Western, Vienna-based diplomat, who follows Iran’s nuclear case closely.

The three Nuclear Fuel stories (Platts asked me to remove the .zip file … I suspect my posting was fair use, but I was moved by Ms. Margaret Ryan’s usage of all caps to indicate that I did NOT have permission), all by Mark Hibbs, are less colorful, but provide loads more detail.

Hibbs reports that Iran is unable to remove metallic impurities from yellowcake (U3O8). Impurities will impede enrichment and may clog cascade piping or collect on surfaces, crashing unbalanced centrifuges.

Apparently the Iranians lacked the sweet skills to execute the Chinese blueprints—something the Chinese told the Iranians after cutting off assistance. Iran has subsequently taken an alternative, less sophisticated route to purifying U3O8:

In 1990, China had agreed to build UCF in Iran as a turnkey project. When in 1997 the U.S. had persuaded China not to build the plant in Iran, China nonetheless sold Iran blueprints for the conversion plant. Iran built the plant according to Chinese specifications between 1998 and 2003. Without additional hands-on assistance from Chinese engineers, however, Iran failed to master the U3O8 purification process.

In 2004, Iran responded to the difficulties by removing mixer-settlers called for by the Chinese process, and replacing the equipment with pulse columns.

The pulse columns are of Iranian design and were tested at the Tehran Nuclear Research Center (TCNC), the leading center of Iran’s uranium conversion research and development program during the 1990s and before UCF was built. During the R&D program for the pulse columns, Iran first test operated columns made of glass before it tested, and then began installing at UCF, columns made of metal. Vienna officials said Iranian experts told the IAEA that the Chinese purification process was “too complex” to master without outside assistance.

Hibbs also reported that Iran has suffered uranium process losses of about 40% and has not been able to demonstrate operation of the plant at even half of its declared throughput of 200 metric tons U as UF6.

One weird thing: One of Hibbs’ articles says the opposite: That Iran had trouble with pulse columns and switched to mixer-settlers. IAEA DG Mohamed ElBaradei told the Board that Iran moved “from mixer settlers to pulse columns” because the former “was technically and mechanically complex and more difficult …” But this is way outside my expertise, so further clarification is appreciated.

Update: The original post had a sweet illustration from the New York Times, but a reader noticed the graphic—however handsome—was wrong. Damn, that’s metaphoric.