Abstract: Although domestic nuclear power plants (NPPs) have established on Duty Emergency Response Organization (DERO) in accordance with relevant standards and guidelines, the guidelines usually have not specified the requirements for the minimum-DERO in detail, resulting many differences in the configuration and scale of the minimum-DERO among different NPPs. Through investigating of the current situation of DEROs in NPPs, based on the results of classification analysis and evaluation of typical accidents, the dynamic understanding of the minimum DERO at different stages has been deepened. The requirements for the minimum DERO personnel are determined according to three categories of personnel, namely “on-duty” “time-limited” and “others”. The duty arrangements, examination and verification, logistics support and optimization methods of the minimum DERO have been analyzed. A general formulation method and process for the minimum DERO have been established. The setting principles, positions and personnel composition of the minimum DERO for dual-unit plant sites have been proposed. The quantitative criteria for the general minimum DERO and suggestions for the minimum DERO for dual-unit plant sites have been provided, which has provided a technical reference for NPPs to formulate nuclear emergency plans.

Key words: nuclear power plants, nuclear emergency, minimum on Duty Emergency Response Organization