Fire hazard assessment of Candu plants

The requirements for fire protection of CANDU nuclear power plants have evolved from the rule based requirements applied to the early plants to the performance based standards of the 1990's. The current Canadian standard, CAN/CSA N293 (1995), requires a documented fire hazard assessment to be used in the design of fire detection and extinguishing systems. The Fire Hazard Assessment method uses a standard format for all fire zones in the plant to assess the adequacy of the fire protection measures, first applied to the CANDU 6 design at Wolsong 2/3/4. The grouping of safety related systems into two independent and well separated groups was found to have a large positive impact on the ability to maintain safety functions during a fire. The new CANDU 9 design builds on the experience gained from previous designs, with improvements in grouping and separation and fire protection system design. (author)