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The Nuclear Energy Agency (NEA) is a specialized agency within the Organization for Economic Co-operation and Development (OECD). The International Fire Data Exchange Project (OECD FIRE) was designed by the NEA to encourage multilateral co-operation in the collection and analysis of data relating to fire events in nuclear power plants. We used Python advanced software to analyze the data related to CANDU reactor plants in Canada from the OECD FIRE Database, while providing weighting factors/percentage tables to be used in CANDU Fire probabilistic risk assessment analysis. We also used 5 different time-series methods to predict future potential fires in CANDU reactors, compared the results from different methods, and identified the best method to predict future fires in CANDU power plants.

A fuel survey was carried out at all operating CANDU reactors in Canada in 5 sites (Bruce A, Bruce B, Darlington, Pickering, and Point Lepreau). The survey used the National Fire Protection Association 557 combination method for the fire zones that contain fire safe shutdown analysis equipment. A fire zone group list for the sites was developed to combine fire zones with similar functions; 38 fire zone groups were produced from this exercise. The results of the survey show that the average fuel load density for all 1230 fire zones is 170.1 MJ/m2, and the average fuel load is 79 183 MJ. The maximum fuel load density is 1319 MJ/m2, and the maximum fuel load is 2 785 404 MJ. High-energy arcing faults risk was found in 254 fire zones out of the 1230 fire zones. Electric fault is the highest ignition source risk present in all 1230 fire zones.

Fire Probabilistic Risk Assessment (PRA) is being introduced to the fire protection engineering practice both locally and worldwide. The commercial nuclear power industry has also experiencing the impact of this new approach. This paper examines the work performed to assess the relative accuracy of fire models for CANDU nuclear power plant (NPP) applications. The Canadian NPP uses some portions of NUREG/CR-6850 in performing fire PRA. Canadian fire ignition frequencies have been provided by International Fire Data Exchange Project. The CANDU Fire PRA Model can quantitatively evaluate plant damage states and core damage frequencies. This model will assist fire engineers in performing CANDU Fire PRA analysis, by recognizing vulnerabilities related to fire events and will contribute to further improvement of the Canadian NPPs’ safety.

Recent research shows that the two predominant failure modes encountered in concealed wood-steel-wood bolted connections at ambient temperature are perpendicular-to-grain tensile splitting and row shear out [1]. The study presented in this paper aims to investigate the fire performance of these connections but with self-tapping screws (STS) acting as perpendicular-to-wood grain reinforcement along with applying fire protection to the metal components, e.g., head and nut of steel bolts and connecting steel plates, of the connections. Two full-size glulam beam end connections were tested experimentally at elevated temperatures while being loaded perpendicular to wood grain to develop bending moment on the connection. Two connection configurations, each involved four steel bolts arranged in two different patterns, were examined. In both fire tests, the connection assemblies were exposed to elevated temperatures that followed the CAN/ULC S101 standard time-temperature curve [2] and each connection configuration was loaded to 100% of the ultimate design load of the weakest connection configuration. The experimental results showed that the influence of the self-tapping screws was significant as it helped in avoiding the occurrence of wood splitting or row shear out, and thus resulted in increased time to failure of the connections in standard fire condition.

The paper proposes a probability-based Monte Carlo life-risk analysis model for fire emergencies. Based on the hazardous conditions in each compartment of a building and the evacuation path of each occupant, the model calculates the probabilities of injury and death determined by fractional effective doses due to heat and toxic gases, considers the probability of death due to fire spread, and produces the probabilities of injury and death for each occupant. Then these probabilities for all occupants are summed to give the total probabilities of injury and death in a Monte Carlo run, and statistics about the total probabilities of all Monte Carlo runs are produced for each fire scenario. According to the statistics and scenario composition, the expected risks of injury and death in the building are calculated. The model is applied to a life risk analysis of 6- and 12-storey apartment buildings. The results show that for these buildings, injuries and deaths are mainly limited to the rooms of fire origin and the effects of building area and the number of storeys on life risk are slight. The predictions for different layouts are in good agreement with the numbers of injuries and deaths given by Canadian and US statistics.

The Canadian Nuclear Power Plants (NPPs) use some portions of NUREG/CR-6850 in carrying out Fire Probabilistic Risk Assessment (PRA). An assessment for the applicability of NUREG/CR-6850 to CANDU reactors was performed and a CANDU Fire PRA was introduced. There are 19 operating CANDU reactors in Canada at five sites (Bruce A, Bruce B, Darlington, Pickering and Point Lepreau). A fire load density survey was done for all Fire Safe Shutdown Analysis (FSSA) fire zones in all CANDU sites in Canada. National Fire Protection Association (NFPA) Standard 557 proposes that a fire load survey must be conducted by either the weighing method or the inventory method or a combination of both. The combination method results in the most accurate values for fire loads. An updated CANDU Fire PRA model is demonstrated in this paper that includes the fuel survey in all Canadian CANDU stations. A qualitative screening step for the CANDU fire PRA is illustrated in this paper to include any fire events that can damage any part of the emergency power supply in addition to FSSA cables.