Steam Generators Replacement and Power Uprate at Tihange 2 Power Plant

The Belgian Tihange 2 nuclear power plant went into commercial operation in 1983 producing a thermal power of 2785 MW. In 1995, the thermal power output was increased up to 2905 MW and the fuel cycle extended to 15 months. Since the commissioning of the plant, the steam generators U-tubes have been affected by primary stress corrosion cracking. In order to avoid further degradation of the performance and an increase in repair costs, Electrabel, the owner of the plant, decided in 1997 to replace the 3 steam generators. This decision was supported by the feasibility study performed by Tractebel Energy Engineering which demonstrated that an increase of 10% of the initial power was achievable together with a fuel cycle length of 18 months. Tractebel Energy Engineering was entrusted by Electrabel to manage the project. A multi-contract strategy was adopted. The new steam generators, designed by Mitsubishi, allow raising the thermal power to 3064MW which is 110% of the initial power by an increase of the primary to secondary heat transfer area. The safety analyses necessary to justify the new operation point and the fuel cycle extension to 18 months were performed by Framatome in association with Tractebel Energy Engineering. The work on site took place during the summer of 2001 and was managed by Tractebel Energy Engineering. The SG replacement itself was performed in 17.5 days by Westinghouse PCI and the plant was reconnected to the grid on August 11, after an outage of 63 days (grid to grid). This paper presents various aspects related to the steam generators replacement project, such as the safety analysis program together with the various works on site, project management, organization, and scheduling.