21 Aug (NucNet): Disposal of weapons-grade plutonium in a repository is cheaper than through the construction and operation of a mixed-oxide fuel (MOX) fabrication facility, a report published by the US Department of Energy (DOE) has concluded.
The report, conducted by a special task force called ‘the plutonium disposition red team’, aimed to find the best way to dispose of 34 metric tonnes of weapons-grade plutonium as agreed by the US and Russia in the Plutonium Management and Disposition Agreement signed in 2000.
The team compared two approaches for plutonium disposal: the construction and operation of a MOX fuel facility which will convert the plutonium into nuclear fuel in order to use it in commercial nuclear reactors (the ‘MOX approach’), and the dilution or down-blending of plutonium using chemicals before storing it in a deep geological repository (the ‘dilute and dispose option’). The team did not consider alternatives such as use in the framework of a fast reactor programme in the United States due to its lack of potential to be used as a solution in the short term.
The report concluded that the ‘MOX approach’, which includes the construction and operation of a MOX fuel fabrication facility, and other necessary activities such as support fuel licensing and reactor modifications, would require a budget increase from the current $400 million (about €360 million) per year to about $700 to $800 million per year until the full 34 tonnes is disposed of.
With the proposed budget increase, the construction of the facility would require 15 years to be completed and about another three years to be commissioned, the report says. This will enable the production of MOX fuel to begin in 2033.
The report says that the ‘dilute and dispose option’ could be executed within roughly the same timeframe as the ‘MOX approach’ but at the current funding level of $400 million per year.
The timeframe can be shortened if the ‘MOX approach’ is discontinued and a “modest increase in funding” is provided for the ‘dilute and dispose option’, the report says. The timeframe can be further shortened by the introduction of several process-optimisation measures discussed at length in the report.
The report also says that the ‘dilute and dispose option’ relies on the availability of national processing and storage facilities for its execution, namely the Waste Isolation Pilot Plant (WIPP) in New Mexico, the Savannah River site in South Carolina and Los Alamos National Laboratory in New Mexico.
According to the report, the use of existing facilities means that no additional liability related to surveillance, decontamination and decommissioning is created, which would have to be taken on by the DOE for the MOX fabrication facility in the ‘MOX approach’. This liability would exist regardless of whether the programme for the disposal of plutonium is ever executed in the facility, the report says.
However, the WIPP facility has been unavailable for waste storage since the February 2014 incident when a radiation leak originated in a disposal chamber about 1 km below ground and exposed more than 20 workers to small amounts of radiation.
In August 2015, the DOE said initial proposals for the reopening of the facility in March 2016 had been postponed indefinitely because of “unanticipated challenges”.
The report nevertheless concludes that the “constructive on-going engagements with the State of New Mexico regarding WIPP restart bodes well” for the plutonium disposal programme.
The report is available online: http://bit.ly/1MC6wWh
