 INES 2 |
Level 2 incident on INES scale concerning a pipe nonconformity in two Cattenom NPP fuel storage pools |
On 18 January 2012, Cattenom's operator (EDF) notified ASN that the absence of a "siphon breaker" orifice on the fuel storage pools of reactors 2 and 3 had been detected during an inspection performed by EDF teams.
During an inspection carried out on 21 December 2011 as part of the measures taken following the post-Fukushima complementary safety assessments, the operator found out that these siphon-breakers were indeed present on the Cattenom NPP reactors 1 and 4, but not on reactors 2 and 3.
On 24 January 2012, ASN conducted an inspection on this subject, in particular concerning the measures taken by the operator. Following this inspection, it required the operator:
* to take immediate compensatory measures, to prevent any risk of accidental emptying of the pool,
* to remedy these nonconformities within 10 days.
The anomalies observed were mended between 1 and 3 February 2012; an ASN inspector went on site to check that the required modifications were correctly implemented.
This nonconformity is a deviation from the design baseline safety requirements. It had no impact on the workers or the environment but did compromise defence in depth. Owing to its potential consequences, this event was rated level 2 on the INES scale.
Event date: Wed, 21-12-2011
