Containment is more efficient, and proliferation concerns are lessened.

Since uranium and plutonium are nuclear weapons materials, there have been proliferation concerns.

Supporters of the provision say there are no proliferation concerns, that only our close allies are covered under the program.

The recovery of high-purity uranium-233 has been raised as a potential nuclear proliferation concern.

U-233 may be intentionally downblended with U-238 to remove proliferation concerns.

Despite these proliferation concerns, Washington has shown understanding of Israel's desire to acquire nuclear weapons and missiles.

However, the arrangement was cancelled a year later due to international pressure because of proliferation concerns.

It is responsible for understanding nuclear threat devices and foreign nuclear weapons that cause proliferation concerns.

This means Helikon-type plants can be relatively small, making the technology a nuclear proliferation concern.

But proliferation concerns have been long-standing and very serious.