VIENNA — Iran is cutting its stock of uranium that is closest to atomic weapons-grade as mandated in a deal with six world powers, the head of the UN nuclear agency said Monday.
But Yukiya Amano noted that the agency remains short of money to be able to monitor Tehran’s compliance with the agreement.
As part of the six-month interim deal, Iran must dilute half of its 20-percent-enriched uranium to a lower grade suitable for use as reactor fuel. Amano told the International Atomic Energy Agency’s 35-nation board that process ‘‘has reached the halfway mark.’’
The other half of the uranium is to be changed into oxide, a precursor of nuclear fuel that is relatively difficult to reconvert to 20 percent. Iran has told the agency it now is working on facilities to carry out that transformation.
Uranium enriched to 20 percent is only a technical step away from the 90-percent level needed for nuclear weapons.
Last month the IAEA said Tehran’s stockpile of 20 percent enriched uranium fell to 354 pounds from more than 460 pounds in January. With further enrichment, about 550 pounds is considered sufficient for the fissile core of one nuclear weapon.
Amano said the IAEA is still short about $2.2 million of the approximately $7.6 million it needs to monitor Iran’s compliance with the deal. Tehran dismisses other nations’ fears that it may want nuclear arms but has agreed to temporarily limit its atomic work in return for some sanctions relief.