Study on Peak Shaving Characteristics of Nuclear Power Unit Based on Molten Salt Heat Storage

doi:10.12096/j.2096-4528.pgt.25063

Abstract

Abstract:

Objectives Nuclear power units have great potential for peak-shaving. However, the peak-valley fluctuations in terminal load and the characteristics of nuclear reactors to maintain stable output seriously affect the safe and efficient operation of nuclear power peak-shaving process. Heat storage technology, which enables the storage of thermal energy, is an important way to solve the imbalance between nuclear power supply and demand. Therefore, the peak-shaving characteristics of nuclear power units based on molten salt heat storage are studied. Methods This study takes an actual nuclear power unit as the research object. Based on the principle of energy cascade utilization, three nuclear power peak-shaving system schemes coupled with molten salt heat storage are proposed: main steam heating molten salt, high-pressure cylinder exhaust steam heating molten salt, and electric heating molten salt. A simulation model of the coupled system is established and supplemented with targeted experimental validation. The system thermodynamic performance under five peak-shaving amplitudes of 5%, 10%, 15%, 20%, and 25% is systematically studied. Results The nuclear power peak-shaving system coupled with molten salt heat storage improves the peak-shaving performance of the nuclear power unit while meeting different heating demands. The high-pressure cylinder exhaust steam heating molten salt coupled system scheme exhibits the best thermodynamic performance, followed by the main steam heating molten salt coupled system scheme, and the electric heating molten salt coupled system scheme performs the worst. Under a 25% peak-shaving amplitude, the energy efficiencies of the high-pressure cylinder exhaust steam heating molten salt coupled system scheme and the electric heating molten salt coupled system scheme are 63.76% and 37.84%, respectively, and the exergy efficiencies are 59.41% and 23.04%, respectively. Conclusions The proposed molten salt heat storage schemes for nuclear power units can be applied to scenarios such as municipal heating supply, providing guidance for the safe and efficient operation of nuclear power units in grid peak shaving.

Key words: nuclear power unit, peak-shaving, molten salt heat storage, integrated system, energy cascade utilization, thermodynamic analysis

CLC Number:

TK 02

Songyang LIU, Yunpeng BAI, Zhidong CHEN, Liang DING, Chaojie SUN, Yanqiang KONG. Study on Peak Shaving Characteristics of Nuclear Power Unit Based on Molten Salt Heat Storage[J]. Power Generation Technology, 2025, 46(6): 1200-1211.

Figures/Tables 16

References 25

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参数	数值
核能输入功率/MW	3 191.16
主蒸汽温度/℃	282.0
主蒸汽压力/MPa	6.615
再热蒸汽温度/℃	270.1
再热蒸汽压力/MPa	0.99
给水温度/℃	226.0
排汽压力/kPa	5.10
发电量/MW	1 211.68
能量效率/%	37.97

参数	数值
核能输入功率/MW	3 191.16
主蒸汽温度/℃	282.0
主蒸汽压力/MPa	6.615
再热蒸汽温度/℃	270.1
再热蒸汽压力/MPa	0.99
给水温度/℃	226.0
排汽压力/kPa	5.10
发电量/MW	1 211.68
能量效率/%	37.97

参数		数值
热网回水温度		40.0
热网供水温度		130.0
主蒸汽加热熔盐方案	高温熔盐温度	272.0
主蒸汽加热熔盐方案	低温熔盐温度	150.0
高压缸排汽加热熔盐方案	高温熔盐温度	172.0
高压缸排汽加热熔盐方案	低温熔盐温度	150.0
电加热熔盐方案	高温熔盐温度	200.0/240.0
电加热熔盐方案	低温熔盐温度	150.0

参数		数值
热网回水温度		40.0
热网供水温度		130.0
主蒸汽加热熔盐方案	高温熔盐温度	272.0
主蒸汽加热熔盐方案	低温熔盐温度	150.0
高压缸排汽加热熔盐方案	高温熔盐温度	172.0
高压缸排汽加热熔盐方案	低温熔盐温度	150.0
电加热熔盐方案	高温熔盐温度	200.0/240.0
电加热熔盐方案	低温熔盐温度	150.0

组成设备	软件组件	细节
蒸汽发生器	蒸汽发生器	蒸汽发生器以整体建模，不同工况下的主蒸汽流量设置为定值
汽轮机	汽轮机	指定各级的排汽焓值；各级组机械效率设定为99.80%
泵	泵	等熵效率为83.0%；机械效率为99.8%
发电机	发电机	发电机效率为99%
加热器	给水加热器；疏水冷却器；除氧器	加热器由给水加热器(冷凝段)和疏水冷却器(疏水冷却段)组成，加热器3为除氧器。规定了每个加热器的上端温差和每个疏水冷却器的下端温差。不同加热器对应的抽汽压力损失范围为3%~5%；热损失忽略不计
再热器	通用换热器	指定热流体的入口和出口温度；指定冷流体的入口温度
凝汽器	冷凝器	指定冷却水的入口温度和压力；指定凝汽器的终端温差
高温熔盐罐/低温熔盐罐	直接存储	指定容器内温度
电加热装置	电锅炉	指定效率