Annual capacity analysis and multi-objective optimization of a nuclear-renewable integrated energy system

The increasing penetration of renewable energy sources in power systems has posed unprecedented challenges to grid stability. As a clean and low-carbon baseload energy source, nuclear-integrated energy systems are playing a pivotal role in energy transition. However, the current understanding of nuclear power units' dynamic response characteristics under variable load conditions remains inadequate, significantly constraining operational flexibility and grid regulation capability. To address this technical bottleneck, this study proposes an innovative integrated energy system that synergizes nuclear and renewable energy, achieving combined supply of heating, cooling, industrial steam, seawater desalination and hydrogen production. By establishing a typical industrial zone scenario, a comprehensive 8760-h dynamic simulation model was developed using TRNSYS platform, with particular focus on analyzing the temporal variation patterns of key equipment capacities. Subsequently, a multi-energy coordination strategy was formulated, optimizing both nuclear baseload operation and flexible regulation requirements. A tri-dimensional evaluation system encompassing energy efficiency, economic benefits and environmental impact was established to comprehensively assess annual system performance. Multi-objective optimization results demonstrate that the system achieves optimal performance at a steam extraction ratio of 0.26, with energy conversion efficiency reaching 37.90 %, payback period of 7.79 years, and annual CO2 emission reduction of 1.2612 million tons.