## 3 Information Requirements Development
The six information requirements from the FRAM model consist of three Input aspects, one Output, one Precondition, and one Resource aspect. The Input aspect of FRAM activates the function or it is transformed to produce the output. The first Input, 'Severe accident response team is ready', acts as the initial Input that activates F.2 for the first time. This information item is categorized as 'Environments' in the knowledge type because the response team availability represents the surrounding situation of severe accident management effort. The readiness of the response team is assumed to be known via communications among personnel. The other two inputs, 'Decision whether to implement the strategy' and 'Long-term monitoring variables', activate F.2 again after certain decisions are taken. The 'Decision whether to implement the strategy' refers to one of these two decisions: to implement the mitigation strategy or not to implement it. The Input that activates F.2 is the decision not to implement the strategy. When the decision taken is to implement the strategy, the related functions are activated, until finally, 'Long-term monitoring variables' are created at the end of the strategy implementation and it activates F.2 again for another strategy selection, if necessary. The 'Decision whether to implement the strategy' is a 'History' (knowledge type) because it only informs of the decision not to implement the strategy and it is known via communications. The 'Long-term monitoring variables' is a 'Variables' (knowledge type) and its readings can be obtained from information support systems. The Output aspect of FRAM is the result of the function. The F.2's Output is the 'Selected mitigation strategy' that is passed to the next (downstream) functions. Although, after careful considerations, the operators may decide not to perform the selected mitigation strategy, they are first expected to perform the selected mitigation strategy. Thus, the 'Selected mitigation strategy' is categorized as 'Goals' (knowledge type) and it is known via communications. The Precondition of FRAM is the conditions that must be satisfied before the function can be performed. The F.2 has one Precondition: 'Information about power plant condition and variables'. This information has to be provided before a mitigation strategy can be selected. The knowledge type of 'Information about power plant condition and variables' is 'Variables' and it can be obtained from 'Information support systems'. The last F.2's information requirement from the FRAM model comes from a Resource aspect, i.e., 'Power plant's operation mode'. The Resource aspect of FRAM is the item that is needed or consumed by the function when it is active. The 'Power plant's operation mode' is needed  
to select the right mitigation strategy. The NPP of our study predefined six operation modes, coded using the alphabet A through F. The 'Power plant's operation mode' is a type of 'States' (knowledge type), not simply 'Variables' because the modes' definition contains multiple variables readings or conditions. This information is known via communications from the personnel who deduct the current operation mode based on the criteria. Before we continue to analyze the information requirements extracted from the decision ladder model, we briefly recall the nature of FRAM and decision ladder analysis. As described earlier, FRAM and decision ladder complement each other by having different perspectives. FRAM is a type of system-based analysis that creates a model of the whole system, whereas the decision ladder is a type of task-based analysis that focuses on the current task. Thus, in the next analysis, the perspective is shifted to the current exact task, not the whole system, which may lead to a different set of information requirements. **Information requirements elicited from the decision ladder model. ** The decision ladder model yields 13 information requirements from 3 states of knowledge: Alert, Information, and System state.