nuclear-news

New report indicates that deep burial of plutonium better and cheaper than MOX reprocessing

NuClear News, April 15  Alternatives to MOX A new report by Frank von Hippel and Gordon MacKerron reviews programs in France, Japan, the UK and the US to dispose of large stocks of separated plutonium in nuclear power reactor mixed-oxide (MOX) fuel. Most of these efforts have suffered long delays and large cost increases and all have failed to reduce plutonium stockpiles. This has led some of these countries to consider alternatives.

A less costly and more effective approach may be to treat plutonium as a waste to be processed into a stable form and deeply buried. These alternative approaches include disposal with radioactive waste or spent fuel or disposal down a 3-mile (5-kilometer) deep borehole. The report recommends that more than one direct-disposal approach be pursued. It also recommends that the countries that share the problem of plutonium disposal collaborate on exploring direct-disposal options.

Finally, it recommends that the quantities of plutonium disposed by the weapon states be verified by the IAEA. The huge cost overruns in the under-construction MOX plant at the DOE’s Savannah River Site in South Carolina led the Obama Administration to conclude in 2013 that plutonium disposal via MOX “may be unaffordable.”

This has revived policy interest in the U.S. in the possibilities of direct disposal of plutonium as a waste. Efforts to convert foreign separated plutonium into MOX fuel encountered technical problems in the UK, forcing the abandonment of the Sellafield MOX Plant. The UK has therefore looked, in at least a pro forma way, at direct-disposal alternatives.

In the late 1990s, the U.S. studied in considerable depth a “can-in-canister” option in which immobilized plutonium would be embedded in some of the high-level reprocessing waste from which it had been originally separated. This was a way to create a radiation barrier around the plutonium like that around the plutonium in spent fuel, which makes plutonium inaccessible except via chemical and mechanical operations controlled remotely from behind thick radiation shields.

The can-in-canister approach also shares the merit with MOX that it just adds marginally to the quantity of an already existing waste form for which a geological repository has to be found in any case. This option may still be of particular interest in the US, which will be disposing of reprocessing waste for several decades into the future.

In France and the UK, where high-level waste vitrification has been ongoing in parallel with reprocessing, it may be impossible to pursue the “can-in-canister” option unless it is planned well before reprocessing ends. There are other options, however. One that appears increasingly attractive is deep borehole disposal. It does not involve a radiation barrier, but retrieval would be much more difficult than from a closed geological repository.http://www.no2nuclearpower.org.uk/nuclearnews/NuClearNewsNo73.pdf

April 18, 2015 - Posted by Christina Macpherson | - plutonium, 2 WORLD