The White House announced last week that the U.S. inventory of highly enriched uranium (HEU) as of September 2013 has been declassified.
“The newly declassified information shows that, from 1996 to 2013, U.S. HEU inventories decreased from 740.7 metric tons to 585.6 metric tons. This reflects a reduction of over 20 percent,” according to a March 31 White House fact sheet.
The White House added that “This announcement marks the first time in fifteen years that the United States has declassified and released information of this kind.”
But that assertion is in error.
In 2006, the Department of Energy declassified and released data on US HEU inventories dating from 2004. See Highly Enriched Uranium Inventory: Amounts of Highly Enriched Uranium in the United States, Department of Energy, January 2006.
Moreover, the DOE report from a decade ago shows that almost all of the 20% reduction in HEU inventories cited by the White House last week had already been accomplished by 2004, when the HEU total was 590.5 metric tons. Thereafter, in the period between 2004 and 2013, the total HEU inventory evidently declined by only about 5 additional metric tons (less than 1%) to 585.6 metric tons. [See correction below.]
But the White House added that “further reductions in the inventory are ongoing; the U.S. Department of Energy’s material disposition program has down-blended 7.1 metric tons of HEU since September 30, 2013, and continues to make progress in this area.”
The latest disclosure was made to enhance nuclear transparency so as to encourage reciprocal disclosures by other nuclear weapons states.
“The U.S. commitment to sharing appropriate nuclear security-related information has also been demonstrated by recent actions such as the declassification of information on the U.S. nuclear weapons stockpile and transparency visits by officials from non-nuclear weapons states to Los Alamos and Sandia National Laboratories,” the White House said. “These actions show that countries can increase transparency without revealing sensitive information.”
Correction I mistakenly wrote that the inventory of HEU in 2004 was 590.5 Metric Tons. But that number was the amount of U-235. (I read the 2006 DOE report wrong.) The actual inventory of HEU at the time was 686.6 Metric Tons.
Therefore, between 2004 and 2013 there was a reduction in the U.S. HEU inventory of 101 Metric Tons. Thanks to Prof. Alan Kuperman for pointing out the error.