# Team-Communication Modeling Framework for Multi-Unit Nuclear Power Plant Accident Analysis
## 3 Results and Analysis
### Case Study
#### 3.7.1 Background Information  
Some background information is needed to increase the readability of the accident scenario and the FRAM-based process model. We briefly described the emergency-response teams and the emergency mobile equipment as follows. The NPP operation in South Korea is divided per reactor unit [46; 51; 52]. One reactor unit is operated by one team called the main control room (MCR) team, consisting of the leader, shift supervisor, and four members: a reactor operator, a turbine operator, an electrical operator, and a shift technical advisor. MCR may request support from field operators (FO). Upon emergencies, MCR requests the creation of emergency-response teams (ERTs) at the safety center (SC). The ERTs consist of an operating support center (OSC), a technical support center (TSC), and an emergency operation facility (EOF). The ERTs are active when the team leader is present. The characteristics of the ERTs are as follows (we provided the ERT descriptions based on the latest obtainable information; however, these descriptions might change as the accident-management plan is updated from time to time). An operating support center (OSC) covers one NPP site. It performs emergency maintenance, material acquisition, fire extinguishment, and personnel rescue. By default, OSC takes orders from TSC. When TSC is not yet active, it may take orders from EOF or decide by itself or by discussions with MCR and SC. Fire extinguishing and rescue tasks require OSC to interact with multiple teams, such as the medical team, field operators, and the local fire department. A technical support center (TSC) is responsible for one reactor unit and one dedicated TSC for one MCR. TSC takes the decision-making authority from MCR and hands it over to EOF when EOF is active. If EOF is not assembled or not yet active, TSC receives the requests from MCR, analyzes them, decides and orders countermeasures back to MCR or OSC/SC, and then updates the plant status to the public. When EOF is active, TSC recommends countermeasures to EOF to support EOF decision-making. By default, TSC relays the EOF decisions to other teams since EOF has a large work scope. Besides that, TSC performs radioactive analysis, distributes protective equipment to the personnel in the field, restricts access to dangerous areas, and orders radiation decontamination tasks to field operators. An emergency operation facility (EOF) covers one NPP site and it is located outside of the site (off-site). EOF holds the highest authority upon activation, and it is responsible for returning the NPP to safety. Critical decisions such as emergency-phase selection, habitability evaluation, resident evacuation, medical support, information sharing with the media, and personnel management are taken by the EOF. It receives status updates from TSC by default and orders accident countermeasures such as the deployment of mobile equipment. It may interact with all internal emergency-response teams as well as external organizations and communities. It interacts with NPPs in other locations to request support. In general, EOF is the contact point for external interactions. The Fukushima accident brought new concerns to the safety regulations of the nuclear industry; thus, countermeasures were prepared [53]. One of them is the multi-barrier accident coping strategy (MACST) developed in South Korea, in accordance with the United States\" \"Diverse and Flexible Coping Strategy\", which aims to prevent and mitigate nuclear core damage by implementing multiple fixed and mobile equipment to recover/maintain power supply, restore the safety functions (core cooling), and complete the safe shut-down of the plant. MACST contains three phases, starting from Phase 1 to Phase 3, and mobile equipment can be requested when Phase 2 starts. The major pieces of mobile equipment used in Phase 2 are a 1 MW mobile generator, high-pressure mobile pump, and low-pressuremobile pump; in Phase 3, they are a 3.2 MW mobile generator and high-flow-rate sea-water pump.