(516.5071) WISE Amsterdam - During the start up operators noticed one pump of Civaux-1
had a more than 2% higher 'debit' (flow) than the other three. According to the regulations they
had to interrupt the restart process provisionally. They will first analyse pump measurements; if
that's of no avail, the pumps themselves will be inspected.
Civaux-1 is one of four of the new N4 nuclear reactor series. The other three being: Chooz B-1,
Chooz B-2 and Civaux-2, each with a capacity of 1516 MW. The N4 reactors are the first 100%
French-designed and -constructed reactors, based on costly Westinghouse know-how. They all
experienced many and long delays, two to three years for each unit. The causes were technical
problems: faulty designs, wrong digital instrumentation and control systems, metal fatigueness,
corrosion cracking, turbine blades breaking, pipe cracks and ruptures and so on (see also WISE NC
501, 505, 507). Owner EDF and builder Framatome both suffered heavy losses. EDF had to lower its
power export in 1998 due to the delayed N4 reactors. Chooz B-1 and B-2 were connected to the grid
in spring 1999. Commercial operation is due by end of this year. EDF's and France's last nuclear
reactor, Civaux-2, was licensed to load nuclear fuel on 27 July 1999. It is expected to be
connected to the grid by end 1999 or begin 2000.
Local and national antinuclear organisations Stop-Civaux and Sortir du nucleaire protested the fuel loading for several reasons:
- a public inquiry had concluded that only one reactor could function on the site, due to very low water levels in the Vienne river, from which Civaux gets its coolant water.
- the reasons for the rupture of the brand-new Residual Heat Removal (RHR) system coolant pipe at Civaux-2 in May 1998 are still largely unknown and the measures taken are not yet validated. A design review by EDF of the N4 reactor was not able to explain fully why the rupture crack occurred. When the other three N4 reactors were inspected, similar cracks in the RHR systems were discovered.
- The EDF design review also identified problems at the Emergency Feed Water (EFW) system on the N4 plants. Earlier this year cracks at the EFW system were discovered at Chooz. EDF has not yet brought forward a proven solution to the risk of proliferation of amoebes in its condenser circuits, which can cause a rare form of encephalitis. The amoebes developed last summer in cooling circuits in other French nuclear reactors. EDF has to install a new system to kill the amoebae before it will be licensed by the French nuclear regulatory agency DSIN, following a rule by the High Council >for Public Health. Due to the low flow rate of the Vienne River, the use of chlorine or peracetic acid is not allowed. EDF will now use an ultraviolet (UV) treatment at Civaux-1 to kill the amoebae.
Sources:
- Nucleonics Week 22 and 29 July 1999
- La Gazette Nucleaire, June 1999
- Press release Sortir du Nucleaire and Stop Civaux 28 July 1999
- AFP, 18 and 22 August 1999
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