The occupational health and conventionally industrial safety risks prevention for construction and operation personnel shall be adequately considered in design stage of nuclear power plants. Among various health and safety risk prevention and control design methodologies, the concept of intrinsic safety design has been widely used and recognized. This paper introduces the related theory of intrinsic safety design concept, and creates a group of risk prevention and control design process and demonstration method based on risk identification, evaluation, mitigation and delivery. This paper also raises a sample to illustrate the application of intrinsic safety design concept in the scheme design of important facilities of nuclear power plant, putting the theory in practice. It indicates the process and method can be applied in design of large scale plant or factory, and finally minimize the occupational health and conventionally industrial safety risks within design scheme as reasonably practicable.