The electricity industry is a highly important infrastructure and a vital prerequisite for the advancement of economic, social, and welfare sectors in all communities and countries. The availability of highly reliable electricity always plays a significant role in the growth of these areas. Thermal power plants, with a 94% share, are considered the main source of electrical energy production in the country and are one of the three pillars of the critical electricity infrastructure. Due to the dependence of other infrastructures on this one, they are always regarded as one of the most appealing targets for attacks. Therefore, if the weaknesses of existing thermal power plants against the spectrum of conceivable threats are not addressed, and if these weaknesses are repeated in future plants, ensuring their continued operation in the event of such threats will likely be highly improbable. Risk assessment is the first step in identifying and addressing the vulnerabilities of this infrastructure.
The research method of the present study, aimed at assessing the risk of a sample combined cycle power plant against deliberate human-made threats, is descriptive-analytical. To collect and analyze data, a mixed-method approach (quantitative and qualitative) was chosen. In the phase of identifying deliberate human-made threats to power plants, a library method (qualitative) was used, and in the risk assessment section, a questionnaire method (quantitative) based on the FEMA risk assessment method was implemented, with the statistical population selected according to the Delphi method.
According to the findings of the research, among the components of the power plant, the turbo-generator buildings, the central control building, and the ancillary facilities have the highest level of risk against conceivable threats, and risk reduction measures are essential for them.

The electricity industry is considered a critical infrastructure and a vital prerequisite for the advancement of economic, social, and welfare sectors in all communities and countries. The availability of highly reliable electricity consistently plays a significant role in the growth of these areas. Thermal power plants, with a 94% share, are regarded as the primary source of electrical energy production in the country and are one of the three pillars of critical electricity infrastructure. Given the dependence of other infrastructures on this one, they are always among the most attractive targets for attacks. Therefore, if the weaknesses of existing thermal power plants against the spectrum of conceivable threats are not addressed, and if these weaknesses are repeated in future plants, ensuring their continued operation in the event of such threats will likely be highly improbable.

Passive defense is viewed as a foundation for sustainable development and one of the most effective and resilient methods of defense against threats. Essentially, passive defense measures encompass various sectors, including energy infrastructure. This type of defense pursues five central objectives: increasing deterrence, reducing vulnerability, ensuring the continuity of essential activities, enhancing national stability, and facilitating crisis management in the face of threats and military actions. Among the most important measures to achieve these objectives is the effective protection against deliberate human-made threats. This study aims to create the necessary groundwork for effective actions in risk reduction by assessing the risk of a sample power plant against human-made threats.
The present research seeks to identify fundamental human-made threats in the components of a power plant. Accordingly, the research methodology is descriptive-analytical. In order to collect and analyze data in a study, both quantitative and qualitative approaches can be utilized. In this research, a mixed-method approach (quantitative and qualitative) has been chosen. In the phase of identifying deliberate human-made threats facing power plants, a library method (qualitative) was used, while in the risk assessment section, a questionnaire method (quantitative) based on the FEMA risk assessment method was employed. The statistical population of each study can be selected using three general methods: (1) probabilistic methods, which are scientifically valid and known as random methods, (2) non-probabilistic methods, known as judgmental methods, and (3) expert or Delphi methods. In the current research, the Delphi method was used for selection.
A combined cycle power plant consists of several gas turbines and a steam turbine. In this type of power plant, a heat recovery boiler is used to utilize the heat present in the exhaust gases from the gas turbines, which can reach temperatures of up to 660 degrees Celsius, to generate the steam needed for the steam turbines. This combination significantly increases the plant's efficiency (in Class E combined cycle plants, efficiency reaches about 54%, in Class F it reaches 58%, and in Class J it reaches approximately 62%). Additionally, the advantages of gas turbines, such as rapid startup and flexibility across a wide load range, can be leveraged. For this reason, many base-load power plants that use natural gas as fuel are currently of the combined cycle type.