Cattenom (France)

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4 * 1300 MW PWR units constructed by Framatome; operation started 1987/88 and 1990/91

Facilities in Cattenom

plantreactor typconstruction startoperation startshut down

"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."



Fire in a cable passageway in the area of the turbine hall. Firefighters have to break down a wall to get to the burning cables.
(source: Greenpeace nuclear accidents calendar)


Three workers were irradiated.


An electrical device overheated and started to smoke. A few weeks ago a fire in a storage space occured.


In the control centre of Unit-3 a filter system failed for 25 minute, which was due to protect the persons employed in an accident against radioactively contaminated iodine. According to safety regulation this filter must be in operation permanently. The incident occurred during a test at the filter system, it was classified on the seven points counting international incident scale on level one. There had already occurred a similar breakdown in block one of the power station in December 2001. In November the blocks one and two had been temporarily switched off after incidents, because the current had failed in an automatic monitor.


Repair of the inner containment at Cattenom-2: the process which involves placing the resin coating over about 700 square meters of inner containment surface must be improved because the coating didn't adhere as well as had been expected.
Containment leak rate after the repair was 0,5%/day, less than half the pre-repair value.
Cattenom-2 was the first of the 1,300-MW-class PWRs to receive the repair. EDF has pledged to repair the containment of all its large PWRs.
The large PWRs feature double containments, the outer one of reinforced concrete to withstand external agressions and the inner one of prestressed concrete to contain gases in case of a core-melt accident. Leaks from the inner containment are collected in the inter-containment space and filtered. The outer containment have passed leak-rate tests with no problem, leading EDF to say there´s no real safety issue. But the inner containment at several of the large PWRs have failed to meet EDF's leak rate criterion of 1,5%/day of the mass of gas, air, and steam inside.
The inner containment leakage problem is more severe at EDF´s Belleville site, where the nature of the local sand and errors in construction led to a containment that didn´t meet the leak-rate test even before operation began.


During refueling outage a plastic plug was found blocking the seal cooling system on 1 of the 2 containment spray system pumps. The plug had been left in place since March. Tests have not revealed the problem.


During startup two MCP pump seales leaked


During refueling outage it was discovered that a fine-mesh filter had been inadvertently left on piping upstream of he containment sump since the last outage in November 1991. Filter (100 x 200 mm) could have considerably reduced the flow of water recirculation from the sump to the containment spray during an accident.


Iinvestigations revealed forgotten fine mesh filter in the containment sump, blocking operation of containment spray system in case of accident.


Smoke extraction system in the rooms containing electric equipment was found to be unavailable due to an error in the programmable controller of the system fans (-> checks at other 1300 MW units).


Both trains of RHR system had been unavailable, because of a blocked FW valve. Reactor cooling was assured by the SG.


During pre-operational testing at 30% power, an operators order for reactor scram did not take effect because of a cabling defect in the relay systems associated with the 2 trains of a control channel.


Scram following a restart test. Excessive cooldown of RCS caused by improper configuration of SG feedwater system (2 valves open instead of 1).


During refuelling outage a fire began due to sparks of solder coming from a sump.


Primary circuit tests showed the pressurizer nozzle seal was leaking, caused by a weld defect. cracks found, caused by IGSCC (later found to be a generic problem).