Alternative route for plutonium destruction

15 July 2009

Tennessee Valley Authority is to negotiate the trial use of MOX nuclear fuel in its power reactors as part of the US-Russian agreement to dispose of weapons plutonium.


An announcement came yesterday from the National Nuclear Security Administration, an autonomous part of the Department of Energy which is in charge of the plan to mix the plutonium oxide with fresh uranium oxide and make mixed-oxide nuclear fuel (MOX).


The NNSA had for some time been cooperating with Duke Energy and the pair conducted two 18-month trials of MOX fuel assemblies in the Catawba 1 reactor, but Duke allowed the contract to lapse in March. TVA, Duke and two other utilities have expressed interest in picking the program back up, but the announcement of the TVA letter of intent strongly suggests talks with TVA are more advanced than those with the others.


However, TVA would have to draw up an environmental impact assessment for the use of the trial MOX assemblies and conduct tests similar to those at Catawba before being given permission to use MOX fuel as routine. Such a requirement represents a major setback to the program, but would not be expected to halt it given that US President Barack Obama and Russian President Dmitry Medvedev both reaffirmed their promises to go through with the destruction of the plutonium only last week.


As weapons fuel, the 34 tonnes of US plutonium obviously represent an enormous amount of stored energy. NNSA said it would be enough for 8500 nuclear weapons or for 200 billion kWh of electricity - approximately equivalent to a large reactor's total output over 20 years. Russia is destroying an equivalent stock, but has decided to use its more directly as fuel for fast reactors instead.


The US plutonium will be put into MOX fuel at a facility to be completed in 2017 at Savannah River, but trial fuel assemblies would have to be made abroad. Those for the Duke trial were made by Areva in France.


TVA is evaluating the use of MOX at Sequoyah 1 and 2, Browns Ferry 1, 2 and 3 as well as future reactors, NNSA said. The company is pursuing the construction of two new Westinghouse AP1000 reactors at Bellefonte, which would be able to operate on 100% MOX fuel loads.