# Team-Communication Modeling Framework for Multi-Unit Nuclear Power Plant Accident Analysis
## 3 Results and Analysis
### Case Study
#### 3.7.2 The Multi-Unit Accident Scenario
These functions have denser connections compared to others (except the supporting background functions), reflecting their importance. Thus, they were selected as the analysis target. For each of the four functions included in the analysis (hereafter, we used the term \"parent function\"), a specialized FRAM model was created, with its scope matched to the parent function, not the entire accident scenario. Table 3 lists each parent function's name and its corresponding FRAM model name. Following the FRAM guidelines, the name of a function is in a verb form, and the name of a model is in a noun form. Due to space limitations, we mainly present the result of the low-pressure mobile pump operation model. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Performers/ERT** & \multicolumn{2}{c}{**Number of Functions**} & **Function Examples** \\ \hline \multirow{3}{*}{MCR} & \multirow{3}{*}{6} & Confirm reactor shut-down; Diagnose accident; Perform accident countermeasures (as described in the procedures). \\  & & & Check the field; Perform countermeasures on the field. \\ \cline{1-1} \cline{3-3  
The concept of the three model types, i.e., the initial, generalized, and specialized FRAM models, is illustrated in Figure 5. The initial and generalized FRAM model had the same analysis scope, namely the entire NPP accident. However, the scope of the specialized FRAM model is smaller; it covers one pre-selected function of the generalized model. In total, four specialized FRAM models were created, one for each of the parent function. \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{1}{c}{**(Parent) Function Name**} & **Specialized FRAM Model Name** \\ \hline Cooperate to connect AAC DG & AAC DG operation \\ Move–operate 1 MW mobile generator & 1 MW mobile generator operation \\ Move–operate low-pressure mobile pump & Low-pressure mobile pump operation \\ Move–operate 3.2 MW mobile generator & 3.2 MW mobile generator operation \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Naming of function and specialized FRAM model. Figure 4: The generalized FRAM model. Two steps of model development were carried out to create the specialized FRAM model. We performed the same model development method for all four specialized FRAM models and described the method in detail using the \"Low-pressure mobile pump operation\" model. The first step of model development is to revisit the initial FRAM model and return the parent function to the original functions. The parent function \"Move-operate low-pressure mobile pump\" in the generalized FRAM model was returned to the series of functions it represented in the initial FRAM model, namely \"Decide equipment allocation\", \"Prepare equipment transport (on-site)\", \"Transport equipment\", and so on. We examined all the aspects of the parent function and included them in the aspects of the specialized FRAM model. For instance, one of the inputs of the \"Move-operate low-pressure mobile pump\" function is \"Request/re-request equipment\". This aspect is included in the specialized FRAM model. Then, since the \"Low-pressure mobile pump operation\" model covered only one piece of equipment, its functions were specialized. The accident scenario involved two types of low-pressure mobile pumps, one for primary cooling (reactor cooling system) and another for secondary cooling (steam generator). Based on our discussions, both pumps are almost always requested together (as in the scenario); however, since they are different function-wise, we differentiated them in the model, adding the words \"primary\" and  
Figure 5: The modeling concept of the FRAM model types (the FRAM models shown are for illustration purposes only; the real models developed in this study are presented in Figures 4, 6 and 7. \"secondary\".