Editor's Summary
11 January 2007
Ceramics under pressure
Most proposals for the geological disposal of spent nuclear fuels involve the separation of plutonium and other actinides for special attention. They are heavy emitters of alpha radiation, and immobilization in ceramics, rather than glass, is the favoured treatment. One group of synthetic ceramics touted for the role is inspired by the geological zircons, which have shown their durability by retaining uranium and thorium isotopes for billions of years. Now a new study of the synthetic zircons used to contain plutonium-rich materials suggests that they are not as durable as was thought. Alpha particles emitted by these isotopes can dislodge atoms in the ceramic, making the material more susceptible to breakdown. This means that radioactivity could leak out after only 1,400 years of storage, well short of the target immobilization time of 241,000 years. On the plus side, this work provides a way of assessing alternative structures for actinide immobilization that might offer greater durability.
News and Views: Materials Science: Displaced by radiation
The mineral zircon suffers more structural damage from the 
-decay of plutonium present in its crystal than was thought. That could have a knock-on effect on strategies for managing nuclear waste.
Rodney C. Ewing
doi:10.1038/445161a
Letter: Quantification of actinide 
-radiation damage in minerals and ceramics
Ian Farnan, Herman Cho & William J. Weber
doi:10.1038/nature05425
First paragraph | Full Text | PDF (249K) | Supplementary information
