Iran recently announced plans to develop nuclear-powered
submarines, requiring enough highly enriched uranium for two nuclear
weapons. Tehran's ambition seems to be more than just a bargaining
chip. Upping the ante on its questionable nuclear program is
dangerous and needless.
After a recent announcement by the deputy chief of the Iranian
navy that it is considering nuclear propulsion for its submarines,
actions have proceeded swiftly. A bill an Iranian Parliament
(Majlis) committee was approved, and debate has followed, parallel
to the latest round of P5+1 talks with Iran in Istanbul, which
concluded last week.
The Majlis debate brought to the arena additional aspects of the
Iranian plans: the use of nuclear propulsion for oil tankers and
possible use of uranium with higher enrichment. There is speculation
that nuclear propulsion will be used as a bargaining chip to trade
away in international talks or as (eventual) justification for
continuing uranium enrichment and get to higher enrichment. Some
have raised questions about Iran's proclamations and its actual
capacity to develop nuclear submarines.
Nuclear powered vessels were not mentioned in the paper
distributed by Iran at the recent Moscow and Istanbul talks. (What
else is in the pipeline that has not been mentioned?)
The issue gets more complicated, since non-nuclear-weapon states
are allowed to remove from IAEA safeguards nuclear material intended
for non-proscribed military use, such as fuel for nuclear
submarines, under arrangements to be agreed with the International
Atomic Energy Agency.
Nuclear-powered vessels around the world
Since the 1940s, about 500 vessels with nuclear propulsion have
been built. Most are nuclear powered submarines that belong to
nuclear-weapons states. The majority of nuclear powered vessels at
sea are also military, such as aircraft carriers. Only a few
countries have constructed merchant vessels with nuclear reactors.
Most of the civilian nuclear vessels are in Russia, which uses
nuclear-powered icebreakers in the Arctic regions.
Currently Brazil and Argentina are the only non-nuclear-weapons
states with plans to build nuclear-powered submarines. Canada had
plans in the 1980s to acquire such vessels to guard its vast Arctic
waterways, but gave them up not least for cost reasons.
Traditionally, fuel for naval reactors uses highly enriched
uranium to reduce reactor size. For example, American submarines use
highly enriched uranium fuel of up to 97 percent enrichment and fuel
for Russian icebreakers is enriched up to 75 percent.
There have been some exceptions. Low-enriched uranium fuel has
been introduced in submarines in France. The "caramel" low-enriched
uranium fuel used in French submarines is known to be around 7.5
percent enriched, which enables enrichment and manufacturing at its
civilian plants. Brazil's planned nuclear submarine is also expected
to use low-enriched uranium fuel. Merchant ships such as the USS
Savannah (US), Otto Hahn (Germany), and Mutsu (Japan) used low-
enriched uranium fuel, but they no longer exist.
Nuclear reactors in vessels are also complex, costly, and varied.
The design of submarine and surface-vessel reactors differ from each
other. With a few exceptions, naval reactors have been pressurized
water reactors. Built to withstand a rough sea environment, long
refueling intervals, and compact in size, naval reactors are built
to much more rigorous standards than other pressurized water
reactors. Due to design constraints, only one third of the energy
produced is used for propulsion. …