Revenue for the fourth quarter was $421.3 million, a decrease of 9 percent compared to the same quarter of 2011. Revenue from the sale of SWU for the quarter was $377.2 million compared to $394.2 million in the same period of the prior year. Revenue from the sale of uranium was $22.4 million, a decrease of $6.3 million from the same quarter last year. Revenue from our contract services segment was $21.7 million compared to $39.5 million in the fourth quarter last year.
For the full year, revenue was $1.92 billion, an increase of $246.3 million from 2011. SWU volume increased 31 percent year over year reflecting the variability in timing of utility customer orders, including orders that USEC and customers have advanced from 2013. The average SWU price billed to customers increased 5 percent compared to 2011, reflecting the particular contracts under which SWU were sold during the periods. Uranium revenue was $26.0 million, a decrease of $105.8 million compared to 2011. The decline in uranium sales in 2012 continued a trend that began several years ago, as our inventories of uranium available for sale have been sold.
Revenue from the contract services segment was $70.3 million, a 66 percent decrease year over year due primarily to the completion of USEC’s activities at the former Portsmouth GDP in September 2011. Revenues from our wholly owned subsidiary NAC decreased $15.0 million in 2012 compared to 2011 primarily as a result of timing in sales related to dry cask storage systems. USEC closed on the sale of NAC on March 15, 2013, and revenue in this segment is expected to decline significantly going forward.In a number of sales transactions, USEC transfers title and collects cash from customers but does not recognize the revenue until low enriched uranium is physically delivered. At December 31, 2012, deferred revenue totaled $123.1 million, compared to $181.5 million at December 31, 2011. The gross profit associated with deferred revenue as of December 31, 2012, was $6.3 million.