INES-event
INES 2

Failure in fissile material accountability

On 6 October 2009, the Commissariat à l’Energie Atomique (CEA) notified ASN of an incident occurred at the nuclear facility dealing with Plutonium technology and so-called “Atelier de Technologie du Plutonium” ATPu located in the CEA Cadarache plant. The ATPu, a facility currently being dismantled, is operated by AREVA NC and the license holder of this facility is the CEA.

The CEA informed ASN that the amount of plutonium deposits in the facility glove boxes was underestimated. The amount of plutonium deposits during the facility operation was estimated to about 8 kg by the CEA. The amount of plutonium collected during dismantling activities greatly exceeds this value and is currently reaching 22kg. According to CEA, it could come to 39 kg.

Following this notification, ASN performed a comprehensive inspection at the ATPu facility on 9 October 2009. This inspection confirmed that the CEA has been aware of this incident since June 2009.


Moreover, ASN requested its technical support organization, IRSN, to carry out an expertise analysis which has been issued on 13 October.

On 14 October 2009, the ASN Commission decided to suspend the ATPu facility dismantling activities, pending the verification of fissile material accountability (ASN Commission decision No. 2009-160 of 14 October 2009).

This incident has no impact on the environment nor on the public. However, the underestimation of the amount of plutonium has led to deeply reduce the security margins provided by the facility design to prevent a criticality accident.

ASN has sent a record to the public prosecutor for failure to observe the terms of incident notification, as prescribed by regulations.

ASN considers that the failure to detect this underestimation of fissile material amounts during dismantling activities and the late notification of this incident to ASN have revealed weaknesses in the safety culture of both the licensee and the operator. Consequently, ASN has decided to rate this incident at level 2 on the INES scale.

The ATPu facility had been operated for 40 years and its main activity had been the production of MOX fuel. The decree of 6 March 2009 authorized the permanent shutdown of this facility and its immediate dismantling.

Location: CADARACHE
Event date: Tue, 06-10-2009
Nuclear event report
Legenda & explanation