Civaux (France)

Map of Civaux

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2 * 1500 MW PWR under construction (Framatome)

Facilities in Civaux

plantreactor typconstruction startoperation startshut down
Civaux-1PWR19881997
Civaux-2PWR19911999
2008-01-13

Civaux-1 exceeded its authorized operating range over 4 minutes.
Due to the bad adjustment of some valves cold water was therefore injected into the steam generator. This amplified the thermal exchange and caused an excessive cooling of the primary circuit and in the following an increase in output of the reactor core.

source: www.asn.fr (French original)

1998-05-12

Electricite de France (EDF) decided last week to defuel all three operating units of its N4 1,450 MW-class reactor series to allow inspection of residual heat removal (RHR) piping for potential defects such as those found late last month at Civaux-1.

Prior to defueling Civaux-1, the RHR bypass pipe that suffered a major leak May 12 will be repaired temporarily to restore the RHR A train.

The removal of fuel assemblies is scheduled for June 15. It will take a week to unload the 205 assemblies. The fuel handling machine could then be shifted to Chooz-B1 and that unit defueled by the month's end.

No fabrication defect was found in a pipe elbow removed from the residual heat removal (RHR) bypass system of Electricite de France´s (EDF) Civaux-1, indicating the cracking in the pipe last month was due to a design defect, utility officials said this week.
The discovery means that EDF´s newest and largest PWRs, the 1,450-MW N4 units at Civaux-1, Chooz-B1 and Chooz-B2, will be down for many months to come as EDF and Framatome investigate the precise cause of the cracking, redesign the circuit, and fabricate and install new designed circuits.
One question still not answered is why the leak occurred first at Civaux-1, EDF´s youngest unit, which had been on line only since December.
Leaking valves contributed to another well known problem of thermal fatigue on EDF´s 900-MW PWR series, affecting auxiliary piping in the safety injection system. The SIS auxiliary pipe cracking, which occurred first in France at Dampierre, was earlier encountered at PWRs in the U.S. and Belgium (Tihange), as well as at Genkai in Japan. EDF has proposed a design modification for that system and DSIN is urging its timely implementation. The backfit will be done on all the utility's similar 900-MW units.

Destructive examination of the cracked pipe elbow on the residual heat removal (RHR) system has shown no manufacturing defect. Electricite de France (EDF) and Framatome are planning replacement of the system on the four reactors of the N4 series.
EDF officials confirmed this week that the backfit will keep the 1,450 MW-class units off line until late this year.