Officials of the official Atomic Energy Commission (CEA) and the Office for Protection against Ionising Radiation (OPRI) went to the Villejust incinerator in the Essonne department on 13 July. They were searching for a small capsule containing radioactive strontium-90 that had been accidentally jettisoned by a nearby CEA research facility.
After searching minutely through piles of incinerator clinker, they found instead a small metallic particle containing some 4,700 becquerels (Bq) of radium-226. The searchers also came upon an area of four to six square metres by several centimetres deep contaminated with a series of radioactive elements that could only have been produced through nuclear fission.
Their presence at an incinerator that deals only with municipal waste "constitutes a significant incident and one that reveals a failure to apply safety procedures," OPRI noted in a statement. However, the agency said, it was "unlikely" that - with the exception of caesium - any radioactivity would have been emitted from the incinerator's chimney.
CRII-RAD, an NGO that specialises in radiation issues, took a stronger line on the incident this week. In a letter sent to Ms Voynet on Wednesday, the group called for immediate research to establish the full facts. The radioactivity accidentally discovered at the incinerator was the "tip of the iceberg," the group said, and revealed poor controls over "illegal practices permitting elimination at least cost of radioactive wastes".
In line with OPRI's analysis, CRII-RAD said that the radium-contaminated metal particle probably came from a lightning conductor. Radioactive lightning conductors were widely used in France from the 1930s until they were finally banned in the 1980s. The NGO estimates that several tens of thousands of old conductors containing radium are scattered around France each containing radium-226 with an activity between 4m and 800m Bq.
The group also expressed alarm over the patch of ground discovered to be contaminated with fission products. It was highly unlikely, according to CRII-RAD, that these were the only radioactive substances to be have been incinerated at Villejust since it started up in 1984. CEA's involvement in cleaning up the discovered radioactivity was "shocking," CRII-RAD told Ms Voynet since the organisation's laboratories were among the main suspects for having sent the waste to the incinerator.
The strontium-containing capsule that launched the search was eventually found undamaged on 18 July.
OPRI, tel: +33 1 30 15 52 00; CEA, tel: +33 1 40 56 10 00; CRII-RAD, tel: +33 4 75 41 82 50.
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