Abstract

The power manuverability of nuclear power plants (NPPs) is becoming more and more important as governments expand the deployment of renewable energy resources in their energy mix. For this purpose, load follow (LF) operation (LFO) schemes are introduced and tested for different types of reactors. Currently, all NPPs in Korea are operated at a baseload, that is, 100% rated power, and do not rely largely on power tracking control except for startup, shutdown, and some anticipated transients without scram. However, as the contribution of NPPs in the total electricity generation exceeds 50%, LFO may be necessary to balance the intermittency of renewable energy resources. However, the execution of LF can be challenging due to the complex interaction of the nuclear system parameters. Therefore, MODE-K was proposed to investigate the feasibility of LFO for OPR1000 and APR1400. Although MODE-K has shown good results in controlling reactor power and core reactivity, analysis has focused on neutronics aspects only and neglected plant response. A multiphysics LF simulation is therefore undertaken in this work using the multiphysics package RELAP5/SCDAPSIM/MOD3.4/3DKIN to accurately represent the impact of the underlying feedback mechanisms on APR1400 system performance. The simulation uses the three-dimensional neutron kinetics module (3DKIN) to model the reactor core by defining up to eight different control rod banks. Compared to the point-kinetics model of the Reactor Excursion and Leak Analysis Program (RELAP5), the use of 3DKIN yields a more realistic simulation by representing the entire core and reflecting the control rod motion in real time without assumptions related to the axial and radial power distributions, or burnup state.

摘要

随着各国政府在其能源结构中扩大可再生能源的部署，核电厂 (NPP) 的电力可操纵性变得越来越重要。为此，引入了负载跟随 (LF) 运行 (LFO) 方案，并针对不同类型的反应堆进行了测试。目前，韩国所有的 NPP 都在基本负载下运行，即 100% 额定功率，并且除了启动、关闭和一些没有紧急停堆的预期瞬变之外，不主要依赖功率跟踪控制。然而，由于 NPPs 在总发电量中的贡献超过 50%，LFO 可能需要平衡可再生能源的间歇性。然而，由于核系统参数的复杂相互作用，LF 的执行可能具有挑战性。所以，提出了 MODE-K 来研究 LFO 对 OPR1000 和 APR1400 的可行性。尽管 MODE-K 在控制反应堆功率和堆芯反应性方面显示出良好的效果，但分析只关注中子学方面而忽略了电厂响应。因此，在这项工作中使用多物理场包 RELAP5/SCDAPSIM/MOD3.4/3DKIN 进行多物理场 LF 模拟，以准确表示底层反馈机制对 APR1400 系统性能的影响。该模拟使用三维中子动力学模块 (3DKIN) 通过定义多达八个不同的控制棒组来对反应堆堆芯进行建模。与 Reactor Excursion and Leak Analysis Program (RELAP5) 的点动力学模型相比，