Objective At present, the research and application of nuclear heating mainly focus on the third-generation nuclear reactor or steam extraction as heating source, while few focus on high-temperature gas-cooled reactor (HTGR). Existing control schemes for parallel heat exchangers at the same level in the third circuit mostly adopt uniform load distribution, which is only suitable for long-term stable high-load operation conditions. To improve the safety, regulation performance and heat exchange efficiency of nuclear heating units, based on the characteristics of HTGR nuclear power plants, this article analyzes the main steam split heating mode of nuclear heating units and optimizes the control scheme of parallel heat exchangers at the same level in the third circuit.

Method Taking a main heating unit of a 600 MW modular HTGR as the research object, the unit process flow and control principles of the HTGR unit were introduced. Its third-circuit heating scheme, heat exchanger selection and heating regulation logic were investigated. Combined with actual operation requirements, three heat load distribution schemes for heat exchangers, namely uniform load distribution, priority full-load distribution and neutralized distribution, were analyzed and compared under various heat load conditions.

Result The neutralized distribution scheme that balances heat transfer efficiency, regulation capability and equipment service life is selected, and the corresponding heat exchanger regulation strategy is proposed.

Conclusion A control scheme of heat exchangers for nuclear heating units is developed.