Plutonium raises more difficult issues. Because, at least in
principle, all mixtures of plutonium isotopes could be used to
make a nuclear explosive device, plutonium cannot be blended
to a highly proliferation resistant form in the same way that
highly enriched uranium can. The NAS study identified two
leading candidate approaches for reducing the accessibility of
weapons plutonium to a level corresponding to the 'spent fuel
standard'. They are:
* The current reactor/spent fuel option, which would use
light-water reactors or Canadian deuterium-uranium reactors of
currently operating types or evolutionary adaptations of them,
employing mixed-oxide fuel in a once-through mode, to embed
the weapons plutonium in spent fuel similar to the larger
quantity of such fuel that will exist in any case from
ordinary nuclear electricity generation
* The vitrification with wastes option, which would immobilise
the weapons plutonium together with intensely radioactive
fission products in heavy glass logs of the type planned for
use in the immobilisation of military high level radioactive
wastes.
All options should be evaluated carefully to determine which
offers the best solution for long term disposition of former
weapons plutonium, including any new possibilities that emerge
as nuclear disarmament proceeds.
The security risks of plutonium in spent fuel are not zero,
and this is so whether the plutonium is of military or
civilian origin. So while it is very worthwhile to provide for
weapons plutonium, as rapidly as possible, the same chemical
and radiological barriers to diversion and theft for weapons
use as exist for reactor grade plutonium in spent fuel, it is
also important that safeguards and protections applied to all
spent fuel are adequate in relation to the residual security
risks posed by such material.
Work should be accelerated on development of techniques for
IAEA safeguarding of former weapons use fissile material. The
nuclear weapon states should work closely with the IAEA to
develop methods which provide the high level of assurance
needed without compromising sensitive information.
Civil Fissile Material
In principle, plutonium of any isotopic composition (apart
from plutonium containing 80 percent or more of the isotope
Pu-238) can be used in nuclear explosive devices, and for IAEA
safeguards purposes all plutonium (other than Pu-238) is
regarded as a 'direct use material' that can be used in the
manufacture of nuclear explosives. Because of the short time
needed to convert direct use material into components for a
nuclear explosive device it has been suggested that
verification of a nuclear weapon free world would be
simplified if plutonium recycle did not occur. Use of
plutonium in civil power programs is not proscribed by the
NPT, however, and a number of countries have formed the view
that they have no alternative to plutonium use in their civil
fuel cycle if they are to meet their electricity supply needs.
Such states have invested large sums in civil plutonium use.
Plutonium is produced as a natural consequence of the
irradiation of U- 238. The production of plutonium in a
conventional reactor is therefore unavoidable. In practice,
plutonium for nuclear weapons purposes is produced in
dedicated reactors where burn-up levels, hence Pu-240 and
Pu-238 content, can be minimised and there is no doubt that
plutonium at a suitably low burn-up level is extremely
attractive for nuclear weapons purposes, and that 'reactor
grade' plutonium is less so. History shows that reactor grade
plutonium has not been a material of choice for weapons use.
Nevertheless, plutonium use in the civil fuel cycle raises a
number of issues including the requirement that strict
controls be applied through application of safeguards,
physical protection and rigorous national accountancy and
control. Because of the sensitivity of this material, any
stockpiling of plutonium by a non-nuclear weapon state beyond
legitimate energy needs would be of security and proliferation
concern and could result in doubts about the viability of a
nuclear weapon free world.
It is essential that the control regime for civil plutonium
use continue to deliver high levels of confidence that such
material remains in exclusively peaceful use. States using
civil plutonium also have a duty to ensure that by doing so
they are not creating regional or wider tensions. This
obligation is especially cogent regarding assurances that they
are not stockpiling fissile material in excess of normal civil
operational requirements for nuclear energy requirements. One
means of doing this would be for such states to increase
transparency regarding their management and use of fissile
material by publishing details of their projected fissile
material needs and fissile material holdings. Once a
comprehensive, voluntary arrangement is operating steps could
be taken to develop a treaty requiring all states to declare
and account for their stocks of fissile material.
A correct balance must be struck by the international
community between the interests of states using weapons grade
or direct use material for civil purposes and the wider
general interest in ensuring that use of such material does
not result in proliferation pressures or frustrate achievement
of a nuclear weapon free world.
One possibility may be to draw a distinction between plutonium
of different isotopic grades and to use this distinction both
for safeguards purposes and for a proscription on the
separation of plutonium of an isotopic composition which makes
it attractive for weapons use. If combined with a prohibition
on production of uranium at or near weapons grade and the
cut-off convention (which would apply only to fissile material
produced for explosive use), this would stop production of all
nuclear material at or near weapons grade. This would
constitute an important confidence building measure in support
of the nuclear non- proliferation regime and the elimination
of nuclear weapons. Weapons grade nuclear materials have very
limited use in civil nuclear activities and therefore a
prohibition on their production should not cause practical
difficulties with any ongoing legitimate civil (or military)
requirement for such materials being met from existing stocks.
Were a state to be producing significant quantities of
separated plutonium at or near weapons grade, the application
of safeguards measures, though technically sound, would not
provide the requisite degree of assurance about the future
intent of the state concerned. The best way of building
confidence is to avoid production of material of this kind.
Where reprocessing of low burn-up material is proposed,
arrangements could be put in place to ensure such material is
reprocessed in stream with high burn-up material, such as
normal spent fuel, so that the resultant product will have a
sufficiently high proportion of the higher plutonium isotopes.
The clearest example of potential large scale incidence of low
burn-up plutonium is the blanket material from fast breeder
reactors. Plutonium in fast breeder blankets is the equivalent
of very low burn-up, its isotopic composition being similar to
weapons grade (or even 'super grade', i.e around 3 percent
Pu-240). Since production of blanket material is the major
reason for operating fast breeders (i.e to obtain plutonium
for recycle), obviously it is not practicable to proscribe the
production of such plutonium in irradiated blanket material.
It is possible however to avoid the production of low burn-up
plutonium as a separated product, by ensuring that irradiated
material containing any such plutonium will only be
reprocessed in stream with high burn-up material (e.g. fast
breeder core fuel, or light water reactor fuel).
It is an unfortunate consequence of the current practice of
not differentiating between plutonium grades for safeguards
purposes that special attention is not directed to plutonium
having the isotopic characteristics of greatest proliferation
concern. Where irradiated fuel containing low burn-up
plutonium is stored in spent fuel ponds, there is a strong
case for subjecting it to particular safeguards attention to
provide extra assurance of non-diversion.
A possible risk of drawing a distinction between the various
grades of plutonium is that it could result in pressure to
consider whether controls on reactor grade plutonium should be
reduced. A further consideration is that enhanced controls on
low burn-up plutonium would probably increase the costs of
safeguarding plutonium from weapons dismantlement. In
circumstances where safeguards resources are under great
pressure, it would be necessary to determine whether using
such resources to increase controls on low burn-up plutonium
would be the most cost-effective option in terms of benefit to
the non-proliferation regime. Therefore there would be merit
in investigating various categories of plutonium in terms of
applicable safeguards measures and resulting verification
costs.
As to a prohibition on production of uranium at or near
weapons grade, apart from minor quantities for laboratory use
the only civil requirement for highly enriched uranium (at or
above 20 percent U-235) is in certain research reactors and
critical assemblies. In recent years there has been a
concerted program of converting research reactors from highly
enriched uranium to low enriched uranium fuel, and very few
still operate on highly enriched uranium. Fewer still operate
on highly enriched uranium fuel of weapons grade, the recent
decision by Germany to proceed with a new reactor using such
fuel being a controversial example. To the extent that use of
highly enriched uranium cannot be avoided in advanced
scientific research, obtaining this material from the very
extensive stocks held by the nuclear weapon states will help
run down those stocks and obviate any further production.
Highly enriched uranium is also used by some of the nuclear
weapon states in marine propulsion reactors for both surface
ships and submarines. States using highly enriched uranium for
this purpose have adequate stocks and do not require further
production.
A prohibition on production of all nuclear material at or near
weapons grade may prove a practical step of considerable value
in support of the eventual elimination of nuclear weapons and
could be included in the proposed cut-off convention or a
complementary international agreement.
As nuclear disarmament gathers pace the amount of fissile
material to be brought under IAEA safeguards will increase
dramatically. This material will be made up of plutonium and
highly enriched uranium components from dismantled weapons and
fissile material inventories not stored in weapon component
form. As a guide, the United States currently has about 84
tonnes of weapons grade plutonium and about 500 tonnes of
weapons use highly enriched uranium. Russian stocks are at
least equal and could be higher. It is essential that former
weapons fissile material be afforded the highest standards of
accounting and control and physical protection to ensure that
it does not contribute to concerns about cheating or leakage
to other actors.
As agreed at the Moscow Nuclear Safety and Security Summit,
fissile material removed from weapons should be made subject
to IAEA safeguards as soon as practicable. This will have to
be done in a way that ensures that sensitive information
relating to weapons design is protected. The options for doing
this are either to convert the material to forms which do not
reveal weapons information when accounted for by traditional
IAEA safeguards measurement techniques, or to develop new
techniques to account for the material in component form
without revealing sensitive information. Both of these methods
for protecting weapons design information appear technically
feasible but require further development.
Tritium
Tritium, a radioactive isotope of hydrogen, is an essential
ingredient of most modern nuclear weapons, both for initiation
of the fission reaction and for enhancing or boosting that
reaction. It is subject to rapid radioactive decay - its
half-life is 12.3 years - so there is no doubt that an
appropriate control regime could play a major part in the
elimination of nuclear weapons. While pure fission nuclear
weapons can be made without tritium, there would be profound
design consequences, e.g. they would have to be physically
larger for the same yield, hence less easily deliverable.
Tritium has a number of non-nuclear uses, and Canada, the
major civil producer, has established a regime of peaceful use
assurances and bilateral accounting for tritium supply. This
might form the basis for an international tritium control
regime although it is expected that verification arrangements
would also be required.
The nuclear weapon states are unlikely to accept inclusion of
tritium in the proposed cut-off convention because of the
changes to force structures this would require and consequent
effect on deterrence. Nonetheless, such controls will be an
important part of the disarmament process and associated
verification arrangements and it would be surprising if the
nuclear weapon states did not come to recognise that it is in
their own interests for an appropriate regime to be
established in due course. A practical step would be for the
nuclear weapon states and other states to commence a detailed
study of how such a regime might operate, and what would be
acceptable to the nuclear weapon states and to the
international community at large.
Funding
It is essential that the international community recognise
that laying the foundation for a nuclear weapon free world
will require additional resources. At the US/Russian bilateral
level this will include funding verification measures for
bilateral monitoring of the early stages of disarmament such
as warhead dismantlement and initial monitoring of fissile
material removed from warheads. This process would probably be
extended to the other nuclear weapon states when they join the
disarmament process with accompanying resource requirements.
Resources will also be needed for the multilateral safeguards
system in particular to strengthen the IAEA's capacity to
detect undeclared nuclear activity and to apply safeguards at
nuclear weapon state fissile material production facilities
under a cut-off convention.
The IAEA's safeguards budget is approximately US $75 million
per year and provides a considerable security benefit for a
modest outlay. IAEA safeguards are under great pressure
because of the need to apply safeguards at an increasing
number of facilities. The demands nuclear disarmament will
make of the Agency will add to this pressure. While the 93+2
program is intended to improve the efficiency as well as
effectiveness of IAEA safeguards, it is inconceivable that
existing levels of funds could be stretched to include the
coming demands on Agency safeguards.
The political commitment to eliminate nuclear weapons must be
matched by a willingness to make available the resources
needed for nuclear disarmament including for effective
verification. The amounts involved are likely to be
considerable, especially for dismantlement of weapons and
disposition of their fissile material content, but very much
less than developing, maintaining and upgrading nuclear
arsenals. The costs of verification also need to be weighed
against the substantial contribution to global, regional and
national security effective verification of a nuclear weapon
free world would make.
Infrastructure Dismantlement
Part of the penultimate stage before final elimination of
nuclear weapons should be the sequential destruction of
nuclear weapons facilities. The object of this infrastructure
dismantlement would be to discourage any breakout by making it
a drawn-out, highly visible, large-scale, costly process.
The infrastructure dismantlement phase would begin with
disclosure by the nuclear weapon states and any remaining
undeclared weapon states and threshold states of their
infrastructure for the production and assembly of the various
elements of weapons. They would also need to agree to
international monitoring to verify that weapons production has
halted and that the capacity to resume production has been
essentially eliminated. This would require agreements on
infrastructure declarations, monitoring and dismantlement
processes. Reductions in stockpiles of warheads would
continue.
At this stage the nuclear weapon states and any remaining
states presumed to have a nuclear weapons capacity should
compile annotated charts tracing each critical element of
their weapons back out into the economy through the fabricator
up to whatever level technical specialists may designate. At
this stage of nuclear weapons elimination there can be no
valid reason not to make full disclosure of this supply net
and then to eliminate those critical elements whose retention
could shorten the time and cost of resuming weapon production.
There may be a need to allow the retention of some facilities
on a care and maintenance basis for a period of time to
provide reassurance to the nuclear weapon states until their
confidence in the process has increased sufficiently to allow
them to complete the task. Any cheating at this stage would
require clandestine infrastructure which would need to be
supplied with fissile material and the verification
arrangements for a cut- off convention should be able to
detect any clandestine activities at this stage in the process
of disarmament.
More should not be expected of infrastructure dismantlement
than it can deliver. In the period immediately following
elimination any former nuclear weapon state could rapidly
reconstitute a few bombs using plutonium recovered from spent
fuel, assuming it was prepared to abrogate the relevant
treaties and the international community did not act to stop
it.
By the time the elimination phase of nuclear disarmament is
reached the nuclear weapon states and the undeclared weapon
states and threshold states will have halted production of
weapon material, accepted safeguards on their facilities for
enrichment and for plutonium separation and on material flows
from those facilities and dismantled the infrastructure for
the production of weapons. Ensuring the maximum degree of
transparency during these processes is of central importance.
The Elimination Phase
As the nuclear powers go into their final countdown, there may
be resistance to rapid elimination should the nuclear weapon
states want a pause of some years to assure themselves (and
others) that this elimination of bomb-building capabilities
was both genuine and stable. A penultimate step to elimination
might be the reduction of nuclear forces to very small
residual levels - possibly but not necessarily equal --
- that would be retained until it is clear that a viable
support regime for a nuclear weapon free world is in place.
The small residual weapon stocks would be reassuring to the
nuclear weapon states though not to many others, since it
would mean that the world of mutual deterrence had not yet
vanished. These residual forces would then be eliminated
simultaneously.
Such a stalemate would be less likely if the strengthened
safeguards system currently being developed by the IAEA is
instituted quickly and further developed over the course of
the nuclear disarmament process. In addition, successful
operation of verification during the steps toward disarmament
on such sensitive tasks as eliminating weapon assembly
facilities and reducing weapon stockpiles would enhance
confidence that the very last stage was indeed going to be
executed in strict compliance with treaty commitments.
Canberra Commission Report Continued
Proposition One