The end of the cold war left the United States with a surplus of weapons-grade plutonium. Much of this material is found in a key nuclear weapon component known as a pit. In 1997, DOE announced a plan to dispose of surplus, weapons-grade plutonium through an approach that included fabrication of plutonium into MOX fuel for use in domestic commercial nuclear reactors. In 2000, the United States and Russia entered into a Plutonium Management and Disposition Agreement, in which each country pledged to dispose of at least 34 metric tons of surplus, weapons-grade plutonium. Through a protocol to the agreement signed in 2010, the United States and Russia reaffirmed their commitment to dispose of surplus, weapons-grade plutonium as MOX fuel in nuclear reactors, and the agreement entered into force in 2011.