Heavy water, formed with a hydrogen isotope, is not radioactive but has research and medical applications and can also be used to produce weapons-grade plutonium.
The
heavy water being purchased from the Atomic Energy Organization of Iran will be shipped to the Oak Ridge National Laboratory in Tennessee, where it would be used for research purposes.
In the late 1980s, a leakage of
heavy water happened at the same plant, which led to its closure for several months.
The paras reached a basement room containing the master safe and 286 cells with a six-month supply of
heavy water. Six worked there, attaching explosives to the safe, while four guarded their line of retreat back along the cables.
Canada has shut down its
heavy water refining plants and has been left with large stockpiles of
heavy water it can't export as more countries move toward building light-water reactors.
The nuclear reactors are based on thermal
heavy water technology.
When the researchers repeated the experiment in
heavy water, the differences disappeared.
Tritiated
heavy water is pumped from the nuclear power plant to the separation centre in batches.
The report also said Iran had continued with its
heavy water projects.
Two atoms of it, bonded with one of oxygen, form a molecule of "
heavy water." Water that has been highly enriched in such molecules is itself known as "
heavy water," and is extremely effective at slowing down the fast-moving neutrons that drive nuclear chain reactions.
"If they said it's operational, if it's producing
heavy water, that would be a big breakthrough," said David Albright, a former weapons inspector, who now heads the Institute for Science and International Security.
Documents released to the BBC's Newsnight programme suggest that an answer given by Dr Howells, right, the MP for Ponty- pridd, wrongly suggested that the UK Government had been unaware that a 20-tonne consignment of '
heavy water' sold to Norway in 1958 would be sold on to Israel.