* Many nuclear submarines run on high-grade uranium fuel
* Experts doubt Iran can make such underwater vessels
* But may provide pretext for enriching uranium further
* Iran denies it is seeking nuclear weapons capability
By Fredrik Dahl
VIENNA, July 5 Iran's announcement that it plans
to build its first nuclear-powered submarine is stoking
speculation it could serve as a pretext for the Islamic state to
produce highly enriched uranium and move closer to potential
atom bomb material.
Western experts doubt that Iran - which is under a U.N. arms
embargo - has the capability any time soon to make the kind of
sophisticated underwater vessel that only the world's most
powerful states currently have.
But they say Iran could use the plan to justify more
sensitive atomic activity, because nuclear submarines can be
fuelled by uranium refined to a level that would also be
suitable for the explosive core of a nuclear warhead.
"Such submarines often use HEU (highly enriched uranium),"
former chief U.N. nuclear inspector Olli Heinonen said, adding
Iran was unlikely to be able source the fuel abroad because of
the international dispute over its nuclear programme.
It could then "cite the lack of foreign fuel suppliers as
further justification for continuing on its uranium enrichment
path", Heinonen, now at Harvard University's Belfer Center for
Science and International Affairs, said.
Any move by Iran to enrich to a higher purity would alarm
the United States and its allies, which suspect it is seeking to
develop the capability to make nuclear bombs and want it to curb
its nuclear programme. Tehran denies any atomic arms ambitions.
It would also likely further complicate diplomatic efforts
to resolve the decade-old row over Tehran's nuclear programme
and may add to fears of a military confrontation.
Several rounds of talks between Iran and six world powers
this year have so far failed to make significant progress,
especially over their demand that the Islamic Republic scale
back its controversial enrichment work.
"Iran is using this submarine announcement to create
bargaining leverage," Shashank Joshi, a senior fellow and Middle
East specialist at the Royal United Services Institute, said.
"It can negotiate away these 'plans' for concessions, or use
the plans as a useful pretext for its enrichment activity."
Iranian deputy navy commander Abbas Zamini was last month
quoted as saying that "preliminary steps in making an atomic
submarine have started"..
He did not say how such a vessel would be fuelled, but
experts said it may require high-grade uranium.
Iran now refines uranium to reach a 3.5 percent
concentration of the fissile isotope U-235 - suitable for
nuclear power plants - as well as 20 percent, which it says is
for a medical research reactor in Tehran.
Nuclear weapons need a fissile purity of 90 percent, about
the same level as is used to fuel U.S. nuclear submarines.
"This is a bald excuse to enrich uranium above 20 percent,"
Mark Fitzpatrick, director of the International Institute for
Strategic Studies think-tank in London, said.
A Western diplomat agreed that it could provide another
possible justification for making highly enriched uranium,
adding Iran could also use medical isotope production as an
"What it all means to me is that they could enrich above 20
percent, or even just say they intend to, and then point to some
or all of these 'justifications'," the envoy said.
Iran says its nuclear programme is for purely peaceful
energy and medical purposes and that it is its right to process
uranium for reactor fuel under the nuclear Non-Proliferation
Treaty, a global pact to prevent the spread of atomic arms.
An Iranian lawmaker this week said parliament planned to ask
the government to equip Iran's naval and research fleet with
"non-fossil" engines, Press TV state television reported in an
apparent reference to nuclear fuel.
While nuclear submarines generally run on highly refined
uranium, merchant vessels can also operate on low-enriched fuel,
Mark Hibbs of the Carnegie Endowment for International Peace
The six powers - the United States, France, Germany,
Britain, China and Russia - want Iran to halt 20 percent
enrichment. If Iran not only rejected this demand but also
started enriching to even higher levels, it would risk
dramatically raising the stakes in the dispute.
The United States and Israel have not ruled out military
action to prevent Iran from obtaining nuclear weapons, sparking
fears of a possible escalation into a new Middle East war.
The submarine statement and this week's missile tests by the
Islamic Republic signalled Iranian defiance at a time when the
West is stepping up the sanctions pressure on the major crude
producer with a European Union oil embargo.
"I see this as an effort to demonstrate Iranian resolve at a
time when sanctions are getting unprecedentedly tight," Joshi,
of the Royal United Services Institute, said.
It is difficult and very expensive to make atomic
submarines. "There is no way that Iran could build a
nuclear-powered submarine," Fitzpatrick said.
Such submarines - which the United States, Russia, China,
France and Britain have - can be at sea without refuelling and
stay under water for much longer periods than those using
diesel, experts said.
Naval reactors deliver a lot of power from a small volume
and therefore run on highly enriched uranium but the level
varies from 20 percent or less to as much as 93 percent in the
latest U.S. submarines, the World Nuclear Association, a
London-based industry body, said on its website.
Iran's announcement is another statement "that they are
capable of producing the most-advanced and prestigious military
technology and, as usual, there is little truth in what is being
claimed", military expert Pieter Wezeman, of the Stockholm
International Peace Research Institute think tank, said.
(Additional reporting by Yeganeh Torbati and Marcus George in
Dubai; Editing by Alison Williams)