国际英语新闻：U.S., Russia sign plutonium disposition protocol

WASHINGTON, April 13 (Xinhua) -- U.S. Secretary of State Hillary Clinton and Russian Foreign Minister Sergey Lavrov signed a plutonium disposition protocol on Tuesday, which is aimed at eliminating "excess weapons-grade plutonium from defense programs. "

The protocol was signed by the two top diplomats on the sidelines of the ongoing nuclear security summit held in Washington D.C..

"The Plutonium Disposition Protocol represents an essential step in the nuclear disarmament process," the U.S. State Department said in a statement.

"The Protocol makes arms reductions irreversible by ensuring that United States and Russia will transparently dispose weapon- grade plutonium from their respective defense programs, thereby preventing the plutonium from ever being reused for weapons or any other military purpose," said the statement.

The signing marks a positive step for the nuclear security summit. Leaders from more than 40 countries are gathering in Washington for the summit, in a bid to secure nuclear facilities and materials in the world.