基于非恒定流过程的内陆核电低放废液排放控制优化

Accompanying the development of inland nuclear power in China,the marine impact of liqiud radionuclides emmission becomes a key restricting factor for the project contruction.It's very necessary to study the optimal control of the liquid radiaonuclides discharge. In this program，the existing research results is restudied and the mumerical model is used to study the dilution characteristics and dynamic dilution capacity of the low-radiactive waste liqiud with influence by kinds of factors.The selection of proper unfavorable hydrological conditions is explored. Through site survey, the technical restricts for the liquid radionuclides discharge is analyzed. Then the representive low water hydrological year is selected and the environmental restricting condition of the low-radioactive liqiud waste dicharge is estiminated. The waste discharge rate then is related to the environmental flow process and the numerical model is used to simulate the concentration variation under the given waste discharge rate. Step by step optimization is done based on the analysis of the simulated concentration. At last, a grading relation model of the liqiud discharge rate to certain environmental flow rate range section is constructed and used for several typical representive hydrological year. The efficiency of the model is evaluated.In summary,comprehensive research approaches such as data analysis, site survey, numerical model and source optimization will be used in the program. The objective is to reduce the radionuclide concentration in the fresh water body as well as possible through available optimal control of the liquid radionuclides discharge. The research results will provide scientific basis for the inland nuclear power plant design and environmental protection.

随着我国内陆核电的发展，放射性液态流出物对内陆水环境的影响成为工程推进重要的制约因素之一，针对内陆水域流量季节性变化的特点，开展低放废液排放控制优化研究十分必要。本研究首先通过已有资料分析和数学模型计算，总结多种因素影响下水库和河道两种典型水域的稀释特点和动态稀释能力，研究不利设计水文年的选取；通过现场调研掌握低放废液排放的技术限制条件。选取具有代表性的设计枯水年流量过程，在环保约束条件下，建立低放废液排放与环境来流量的动态关联模式，结合数值模拟开展排放过程实时优化；针对未知来流量过程，开展排放技术限制条件下低放废液排放量与环境来流区间分级关联模式研究，并在不同典型年流量过程条件下对该模式进行试用，分析其有效性。综合利用资料分析、现场调研、数值模拟和源项优化等研究手段，实现非恒定季节性来流年过程下的低放废液排放优化控制，有效降低环境水体中核素峰值浓度，为核电工程设计和环境保护提供技术支撑。

核电是一种低碳高效的能源。为应对能源需求增长和大气环境污染双重压力，我国正积极发展核电，部分内陆规划厂址正处于积极推进启动阶段。核电在运行过程中产生的低放废液需要排放到环境水体中，内陆受纳水域涉及到饮用水安全，排放标准相比滨海厂址更为严格，目前低放废液排放优化控制是我国内陆厂址面临的关键问题之一。本研究针对内陆水域环境流量季节性变化的特点，开展水文条件动态变化条件下核电液态流出物排放过程优化，主要研究内容包括：(1)调研了核电站低放废液排放方式及排放控制现状，分析了内陆核电排放的水文控制条件，总结了低放废液排放的环境水动力模型现状；(2)提出了依据来流过程进行排放量控制的优化分配模型，并以90%频率典型年来流过程作为基准控制水文条件进行了水域浓度模拟，证实优化模型对降低峰值浓度具有较好效果；(3)针对依托厂址连续三年实际来流过程开展了根据来流过程进行分阶段排放优化以及实时排放优化的模拟试验，结果表明根据流量进行实时排放优化模拟得到下游1km断面上最大浓度峰值比优化前略有降低，断面平均峰值浓度则比优化前略大，断面峰值浓度沿河宽分布比优化前有较大变化。研究对核电工程排放设计和环境保护提供技术支撑。