NB/T 11766-2025 in English

Background and Significance of Standard Development

NB/T 11766-2025, "Technical Specifications for Feasibility Studies of Nuclear Power Plant Heating," is my country's first industry standard specifically addressing feasibility studies for nuclear heating, filling a gap in technical specifications for the comprehensive utilization of nuclear energy. The standard, published on June 30, 2025, and officially implemented on December 30, 2025, was edited by China National Nuclear Power Planning and Design Institute Co., Ltd. and co-developed by several organizations, including Shanghai Nuclear Engineering Research and Design Institute Co., Ltd. and Shandong Nuclear Power Co., Ltd.

With my country adjusting its energy structure and advancing its dual-carbon goals, nuclear heating, as a key area of clean energy utilization, urgently requires unified technical guidance. Drawing on my country's experience in nuclear power plant construction and operation, this standard systematically defines the technical requirements for feasibility studies of nuclear heating, providing a standardized basis for new nuclear power generation and heating projects and the retrofitting of existing nuclear power plants.

Interpretation of core content

Requirements for heating technology solutions

The standard clearly distinguishes between the two technical routes of space heating and industrial heating. Space heating uses a surface heat exchanger to heat the circulating water in the heat network. The design water supply temperature should be 120°C, and the return water temperature should not exceed 30°C, which reflects the energy-saving concept of large temperature difference heating. Industrial heating requires the generation of industrial steam through a steam conversion system. The system configuration includes key equipment such as preheater, deaerator, feed water pump, evaporator and superheater.

Technical requirements for reactor-to-reactor matching

The standard focuses on the coordinated control of the nuclear and conventional islands, requiring that the rate of load change during the commissioning and decommissioning of the heating system should not exceed the load change limit of the reactor power control. Special emphasis is placed on the need to evaluate the comprehensive impact of heating on the reactor-to-reactor matching control scheme, nuclear island transient and accident analysis, and nuclear steam supply system equipment parameters when retrofitting in-service units.

Analysis of Key Technical Points

Heating Scheme Design Principles

The standard establishes the fundamental technical principles for nuclear power plant heating: nuclear power plants should bear the base heat load, adopt an economically efficient heating scheme, and plan and implement it in stages. The design life of heating facilities should be consistent with that of the main project, embodying the concept of full lifecycle management.

Safety and Reliability Requirements

In terms of safety, the standard requires that when the nuclear power unit with the highest heating capacity is shut down, the remaining heating units and other heat sources in the heating network should be able to meet 100% of the production steam requirements for continuous production by industrial heat users. Heating must comply with the minimum guaranteed rate requirements specified in CJJ/T 34 to ensure heating reliability.

Project Implementation Specifications

The project concept section details equipment configuration requirements: heating network heaters should be arranged in multiple rows, with the capacity of each row not exceeding 250MW; the number of heating network circulating water pumps should be determined based on the layout and flow rate; 4 or more units can be operated without equipment pumps; the normal output of the feed water treatment system should meet 0.5-1% of the heating network circulating water design flow rate requirement.

Comparative Analysis of Standard Frameworks

Implementation Recommendations and Precautions

Application Recommendations for New Projects

For new nuclear power generation and heating projects, it is recommended that heating demand be fully considered during the feasibility study phase. Heat load statistical analysis should be conducted in accordance with standard requirements, and an annual heating load continuity curve should be developed. Steam turbine selection should comprehensively consider both heating and non-heating operating characteristics to ensure safe and stable operation of the unit under both conditions.

Precautions for Retrofitting In-Service Units

Heating system retrofits for in-service nuclear power units require special attention to assessing the impact of heating on existing systems. This includes reviewing the capacity of the high-voltage plant transformer, evaluating the layout of medium- and low-voltage distribution equipment, and analyzing the safety impact of heating conditions on equipment such as the turbine flow path and reheat control valves. Retrofit plans should ensure that the unit's existing accident and transient analysis conclusions are not affected.

Techno-Economic Optimization

The standard emphasizes the economic efficiency of heating solutions and recommends determining the heating radius through technical and economic comparisons, employing a long-distance, large-temperature-difference model. Investment estimates and financial analyses should be conducted in accordance with standards such as NB/T 20024 and NB/T 20025, with detailed break-even and sensitivity analyses.

Prospects for Standard Implementation

The implementation of NB/T 11766-2025 will significantly promote the standardized development of my country's nuclear heating industry and provide technical support for the comprehensive utilization of nuclear energy. As nuclear heating technology continues to mature and project experience accumulates, it is expected that more nuclear heating demonstration projects based on this standard will emerge in the future, contributing to my country's clean and low-carbon energy transition.

It is recommended that relevant units, during the implementation of the standard, combine specific project practices and continuously summarize experience to provide a practical basis for subsequent revisions and improvements to the standard, and jointly promote the continuous advancement of nuclear heating technology.