The 1997 U.S.-Russia Plutonium Production Reactor Agreement (PPRA) requires the cessation of plutonium production for use in nuclear weapons.  This is achieved through monitoring to assure that shut down plutonium production reactors in both countries do not resume operations.  NNSA also ensures that weapons-usable plutonium produced by the remaining operational reactors in Russia, estimated to be at least nine metric tons once it is all reprocessed, is placed in secure storage and remains accounted for until transferred to a disposition regime.  NNSA serves as the agreement’s executive agent for the U.S. government, and is responsible for agreement monitoring in cooperation with the Defense Threat Reduction Agency (DTRA).