On June 5, 2008, Russia shut down the ADE-5 plutonium production reactor at the Siberian Chemical Combine, ending plutonium production in Seversk/Tomsk-7. The other plutonium production reactor in Seversk - ADE-4 - was shut down on April 20, 2008.
The only remaining plutonium production reactor - ADE-2 in Zheleznogorsk/Krasnoyarsk-26 - will continue to operate until 2010. Since 1994, the plutonium produced by the three reactors was stored in oxide form and was not used for weapon purposes.
UPDATE 06/09/08: The reactor was stopped at 1:03pm local time. This post on Totalwonkerr.com has links to photos and videos.