Importance of location dependencies such as cable and pipe runs when identifying the vital areas

Abstract

Abstract Vital area analysis study and its application for nuclear facilities have been performed since the late 1970s. The Korea Atomic Energy Research Institute (KAERI) has performed a development of VAI methodology since the early 2000s, and the Vital area Identification Package Expert (VIPEX) was developed to identify vital areas using the conventional Probabilistic Safety Assessment (PSA) models, including internal and external PSA models. This study is to demonstrate the applicability of KAERI's VAI methodology to a hypothetical facility containing processes that could have unacceptable onsite and offsite consequences if interrupted due to a security threat, and to identify the importance of location dependencies, such as cable and pipe runs, when identifying the vital areas. The hypothetical facility is assumed to be a nuclear material processing and storage facility in order to identify the vital areas. The target sets and Top Event Prevention Sets (TEPS) are calculated by two conditions: the first condition is to analyze the target sets and TEPS with information of the cable and pipe runs, and the second is to analyze them without it. It is necessary to consider cable and pipe runs in order to determine accurate and realistic TEPS. If the information about cable and pipe runs of a nuclear power plant is not considered when determining TEPS, it is absolutely impossible to acquire complete TEPS, and the results are distorted. When determining TEPS, it is more efficient, and requires lower costs than other methods using location fault trees to use the plant-specific internal and external PSA models including the information of cable and pipe runs.