The proliferation of plutonium for nuclear weapons purposes is a public concern. Significant quantities of plutonium were present in nuclear arsenals of countries with a nuclear weapons’ capability, particularly, e. g. in the US and the former Soviet Union. Plutonium is managed in nuclear fuel cycles and large amounts of plutonium are present in spent fuel from civil nuclear power plants. The subject has been studied and reported on by the American Nuclear Society and a number of other studies (American Nuclear Society, 1996).

In the short-term weapons grade plutonium from the weapons production progra­mmes is a significant proliferation risk. Weapons grade plutonium has 90% or more plutonium-239 which is the more suitable isotope for explosive applications. An important objective to ensure non-proliferation is to convert such plutonium to a different form, e. g. to the spent fuel standard (American Nuclear Society, 1996). However, the timescales for such action are relatively long, anticipated being as much as 15 years.

The longer-term issue is concerned with the increasing quantities of the plutonium being produced by the civil nuclear power programme. If it is sufficient to leave plutonium in spent fuel, how difficult is it for plutonium to be recovered, etc? There are issues associated with the choice of future nuclear power plants, e. g. whether a fast reactor will be built with a requirement for plutonium fuel. It will also depend on the utilisation or otherwise of advanced fuel cycles, e. g. MOX fuel. Either scenario would require the

Table 2.15. Reasons for deferment of plutonium in the civil nuclear fuel cycle

Minimise global nuclear catastrophe risk from irresponsible factions, e. g. terrorists Limit military applications from civil programmes

Reduce the risk from adverse political changes in nations with existing arsenals Remove international barriers to weapons stock destruction

It is not possible to guarantee protection despite IAEA safeguards and international monitoring Separation of plutonium is not justified by current or anticipated market conditions for the next few decades

Cochran (1996).

separation of plutonium from spent fuel with the increased risks of such action on proliferation.

The threats of proliferation have been categorised in American Nuclear Society (1996) in terms of ‘national’ and ‘sub-national’ threats. National proliferation is defined as the use of weapons grade material or material separated in the fuel cycle for weapons devices, authorised by national government approval. Sub-national proliferation would relate to the threat of seizure of nuclear material by smaller groups of people, acting without the support of government.

Retaining plutonium in spent fuel is likely to be an effective deterrent against sub­national threats, but reprocessing, albeit at small scale, is within the capability of many industrialised countries and so the spent fuel standard barrier does not provide protection at a national level. It was mentioned in the previous chapter that IAEA have defined controls to provide a high degree of protection across many eventualities. Nevertheless, it is clearly the effectiveness (or lack of it) of the implementation of these controls that is the issue. It is an issue of increasing importance as the stocks of spent fuel continue to increase and as the radioactivity of older stocks of spent fuel diminishes, the recovery of plutonium becomes easier.

It is argued by Cochran (1996) that due to the general increase in terrorism in the world and for other reasons, there are strong reasons for deferment of the further chemical separation of plutonium at the present time (Table 2.15).