In particular, strengthening the control on " weapon-usable" fissile materials-highly enriched uranium (HEU) and separated plutonium is essential.

加强控制武器用裂变材料——高浓铀（HEU）和分离钚是极为本质的。

youdao

Until this year, Pyongyang has denied U.S.accusations it possessed a covert HEU, or highly enriched uranium program, in violation of previous agreements.

VOA: standard.2009.09.06

It is almost certain that the country is working with highly enriched uranium (HEU) technology.

ECONOMIST: Asia.view

Acquiring nuclear weapons requires three elements: fissile material (such as highly enriched uranium, HEU, or plutonium), a delivery system and a warhead.

ECONOMIST: Nuclear proliferation

Current law is aimed at phasing out U.S. exports of highly enriched uranium (HEU) precisely to reduce the risk of the material being stolen or diverted by proliferating states for nuclear weapons production.

CENTERFORSECURITYPOLICY: Kyl and Schumer move to monitor uranium exports