Chinese mixer-settlers at UCF

A few weeks ago, I noticed a slight inconsistency in a couple of otherwise outstanding articles by Mark Hibbs regarding Iran’s Uranium Conversion Facility (UCF)

The question concerned the method of extracting impurities from uranium—impurities that might crash Iran’s centrifuge cascades.

The Chinese design called for mixed settlers (like the Iraqi models at left), but the Iranians have switched to pulse colums

Marks Hibbs has penned a very helpful correction (Nuclear Fuels, September 12, 2005) that clear that all up:

Iran’s Uranium Conversion Facility (UCF) was originally based on mixer-settlers for solvent extraction, not pulse columns, which China developed during the early 1990s (NF, 29 Aug., 1). The mixer-settlers were developed during the 1950s, Western officials said.

Around 1993, China began specifying pulse columns at a plant in Hengyang; before that so-called “packed columns” were used there. Blueprints sold by China to Iran around 1997 for the design of UCF, however, specified mixer-settlers. According to the IAEA, during trial operation of UCF in 2004, Iran decided to replace these with pulse columns it had been developing since the 1990s.

Western experts described both pulse columns and mixer-settlers as sub-optimal for removing impurities from U3O8 and said considerable experience is necessary to operate them successfully on a routine basis.

Hibbs was kind enough to e-mail me the correction. He also noted with interest that China chose to specify mixer-settlers in the designs provided to Iran, rather than the pulse columns it installed at Hengyang in the early 1990s.

Why?

Chinese disdain for Iran’s sweet skills? Maybe simple desire to sell only the obsolete technology? The history of this Iran-China deal just keeps getting more and more interesting.