Human Reliability Analysis-Based Method for Manual Fire Suppression Analysis in an Integrated Probabilistic Risk Assessment

Abstract

Fire is one of the most critical initiating events that can lead to core damage in nuclear power plants (NPPs). To evaluate the potential vulnerability of plants to fire hazards, fire probabilistic risk assessment (PRA) is commonly conducted. Manual fire protection features, performed by the first responders (e.g., fire brigade), play a key role in preventing and mitigating fire-induced damage to the plant systems. In the current fire PRA methodology of NPPs, there are two main gaps in the modeling of manual fire protection features: (i) the quantification of the first responder performance is solely based on empirical data (industry-wide historical fire events), and so the plant-specific design and conditions cannot be explicitly considered; and (ii) interactions of first responders with fire propagation are not fully captured. To address these challenges, the authors develop a model-based approach, grounded on human reliability analysis (HRA) and coupled with the fire dynamics simulator (FDS), to model the first responder performance more realistically and consider the interface between the first responder performance and fire propagation more explicitly. In this paper, the HRA-based approach is implemented in an integrated PRA (I-PRA) methodological framework for fire PRA and applied to a switchgear room fire scenario of an NPP. The proposed model-based approach (a) adds more realism to fire PRA and so to risk assessment in NPPs and (b) provides opportunities for sensitivity and importance measure analyses with respect to design conditions; therefore, contributes to risk management in NPPs.

Risk Importance Ranking of Fire Data Parameters to Enhance Fire PRA Model Realism

“…As mentioned in Section 3.1, the I-PRA methodological framework ( Figure 11) developed by UIUC integrates simulation models of the underlying human and physical failure mechanisms with the existing plant PRA through a probabilistic interface [28,74]. The dynamic coupling [75,76] between the human performance and the physical failure simulation in I-PRA is similar in its nature to simulation-based PRA (or dynamic PRA).Methods being researched can be applied for advanced reactors and new plants as industry and the regulatory agency deem advantageous, using dynamic with static coupling or fully simulationbased/dynamic PRA. Meanwhile, the Interface Module ('e' in Figure 11) in the I-PRA offers the possibility of reliably using dynamic simulation approaches linked with the existing PRA of aging plants.…”

Incorporation of technical, human and organizational risks in a dynamic probabilistic fire risk model for high‐rise residential buildings

“…In PRA, human reliability (HRA) is commonly performed to account for the human failure events and the impact of performance influencing factors. A number of recent PRA studies have considered human performance under fire scenarios, For example, Bui et al 21 and Sakurahara et al 22 modelled the first responder performance more realistically and considered the interface between the first responder performance and fire propagation more explicitly in a switchgear room of a nuclear power plant. In a similar application, Wang et al 23 and Kloos et al 24…”