Source: Lauren Vilagram | Albuquerque Journal, May 13

It’s still just a theory, but it’s the best they’ve got.

As investigators explore the possibility that nitrate salts caused a chemical reaction hot enough to melt material in nuclear waste drums at the Waste Isolation Pilot Plant, one thing is clear: No one thought the salts were a problem.

On Valentine’s Day this year, radiation leaked from the deep underground repository near Carlsbad, which holds remnants of the country’s nuclear defense program. The Department of Energy and its contractors have been searching for answers about what happened ever since.

In its only publicized theory, DOE suggested earlier this month that untreated nitrate salts may have combined with “cellulosic material” – in this case, a new organic cat litter used as an absorbent – to cause a reaction that may have released intense heat. The idea is that the organic, instead of inorganic, cat litter not only didn’t do its job but may have precipitated a reaction, according to a former WIPP scientist.

A set of drums from the Los Alamos National Laboratory has been the focus of the nitrate salts theory, although waste from two other sites is also underground where the leak is believed to have occurred and is under investigation.