Abstract: The operation technical specifications of nuclear power plant specifies the operational limits and conditions required by China’s nuclear safety regulations and which must be strictly observed by nuclear power plants. Limiting Conditions for Operation（LCO）included in the operational limits and conditions requires the operability of a series of systems performing safety functions（known as the supported system） and the systems supporting other systems to perform safety functions（known as the supporting system）, and specifies the actions to be taken when the operability requirements are not met. However, when a supported system LCO is not met solely due to a supporting system LCO not being met, except for the required actions of the supporting system related LCO to be taken, there is a lack of clear and unified regulations on whether the supported system needs to take specific actions and there are still ambiguous fields with undefined, incomplete and unsystematic management. Therefore, in the development process of the operation technical specifications for China’s independently designed third-generation nuclear power technology, a set of response strategies for the inoperability of NPP supporting systems are researched and developed simultaneously, and used as an indispensable supporting document for operation technical specifications, which can guide the safe and stable operation of nuclear power plants, and have positive practical significance for improving the level of NPP nuclear safety supervision.