Ten year review of Unit 1 at the Tihange nuclear power plant

The Tihange nuclear power plant is situated 80 km from Brussels and comprises three PWR units. The fire protection of unit 1 was subjected to a thorough analysis. Until 1975, fire protection only safeguarded against the main risks. As a result of the incident at Browns Ferry (USA) in 1975, the Tihange plant owner, together with the regional fire department of the town of Huy, re-adapted the fire protection of unit 1 (1979-1981). In 1985, as part of the 10 year review, efforts were directed towards defining the risk more precisely and making protection against every possible outbreak of fire more efficient. On the basis of the regulations in force, and of the experience acquired during the fire protection design of units 2 and 3 at the site, the following improvements in the fire protection of unit 1 were carried out. Concerning passive protection: definition and implementation of new fire areas to fight against the propagation of a fire and to protect important equipment; sealing of the penetrations through fire resistant walls in order to reconstitute the fire areas; use of self-extinguishing electric cables; installation of fire retention walls around the oil tanks; and replacement of fire doors and ventilation dampers. Concerning active protection: replacement of the old fire detection installation with a new one; addition of local fire detectors; modification of hydraulic fire protection of the primary pumps; installation of automatic actuations for a number of hydraulic protection systems; hydraulic protection of the cable galleries and rooms; improvement of emergency diesel generator protection; protection of electrical boards using Halon 1301; installation of a camera monitoring system inside the reactor building; and installation of a fire control panel which allows the control room to manage fire protection