France: Posssible crack in cooland system in all 900 MW reactors

Nuclear Monitor Issue: 

(May 30, 1997) The French nuclear regulatory agency DSIN uprated a leak of a primary coolant at Dampierre-1 to Level 2 on the International Nuclear Event Scale (INES), DSIN rated the defect in December 1996 at Level 1, the lowest of INES's seven scales.

(473.4689) WISE Amsterdam -The leak of primary coolant water occurred in an auxiliary piping of the Safety Inspection System (SIS). It was discovered in the spring of 1997 that Dampiere was not the only reactor with this problem. Cracks were found on an SIS piping in Dampierre-3 and Fessenheim-2, too. The cracks could penetrate the pipes in less than a year.

In studies the EDF handed over to DSIN on April 16, it was revealed that the cracks have the potential for an unisolable primary coolant leak. A small, undetectable defect could penetrate the wall of the pipes in less than an annual cycle. EDF has so far inspected 12 of the 900-MW reactor series and continues to inspect the other 22 units. DSIN and EDF have agreed that all the 900-MW reactors would be inspected annually until the problem is definitely resolved. An investigation is taking place of the potential consequences of fatigue-induced cracks.

Source: Nucleonics Week, 8 May 1997
Contact: WISE Paris