International efforts to remove highly enriched uranium from Vietnam are complete after a removal operation that has taken almost 10 years of planning.
Since 1983 the reactor at Vietnam's Dalat research centre has been powered by nuclear fuel supplied by Russia.
Sarah Dickerson from the National Nuclear Security Administration (NNSA) in the United States has told Radio Australia's about 16 kilograms of highly enriched uranium have been removed from the country.
"So that's not quite enough to make a nuclear weapon which is estimated to need about 25 kilograms," she said.
"But certainly if you took that and combined it with the material from another secondary country, it's something that could be used by terrorists to make a nuclear weapon."
She says an agreement between the United States and Russia cleared the way for uranium removal from third countries to help prevent theft of the material.
"This was never directed specifically at Vietnam... we were looking at all third countries that had highly enriched uranium from Russia," she said.
"So that included the Czech Republic, Hungary and Libya and several other countries."
Ms Dickerson says the operation in Vietnam has been particularly complex, taking almost 10 years of planning.
She says Vietnam will still use low enriched uranium - material that is enriched to less than 20 per cent - to power their research reactor.
"But that material is considered to be much less attractive by terrorists for use in a nuclear weapon," she said.
The highly enriched material has been sent to a secure facility in Russia where it will eventually be "down-blended" into low enriched uranium for use in research reactors or nuclear power plants.
Although Vietnam is now clear of all highly enriched uranium, the NNSA will continue to work with the country to ensure the low enriched uranium is adequately protected.
There are further plans to remove about 3,000 kilograms from other countries by the end of 2016 to 2017, according to Ms Dickerson.
"We do not necessarily have agreements in place with all the countries that have been identified but we're working on that," she said.