Mechanistic modeling and simulation of water radiolysis for controling the chemistry in Generation-IV supercritical water-cooled reactors

用于控制第四代超临界水冷堆化学反应的水辐射分解机理建模和模拟

• 批准号: 424113-2011
• 负责人: JayGerin, JeanPaul
• 金额: $ 5.83万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: NSERC/NRCan/AECL Generation IV Energy Technologies Program
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=551816
• 关键词: Mechanistic; modeling; simulation; water; radiolysis

The radiolysis of water under operating conditions of both current pressurized water-cooled reactors (~250-330 oC, 10 MPa) and 4th-generation SCW reactors in the future (~430-625 oC, 25 MPa) remains largely unknown. Direct measurements at such high temperatures and pressures, and especially beyond the critical point of water (H2O: tc ~ 373.95 oC, pc ~ 22.06 MPa) are difficult, and computer simulations are an important route of investigation. The objective of this work is to obtain an enhanced understanding of the effects of radiation (fast neutrons, gamma-rays, recoil protons/Oq+ ions, q = 1-8) on aqueous systems in the reactor cores, in order to specify a chemistry control strategy that minimizes corrosion and degradation of reactor components resulting from the radiolytic formation of oxidizing species such as .OH, H2O2, O2, and O2.-/HO2.. Our long-term goal is to develop a benchmark SCW reactor radiolysis model using coupled molecular dynamics (MD) and Monte-Carlo (MC) simulations. This project is based on preliminary results (obtained in our laboratory) that suggest that the heterogeneous molecular structure of SCW (high-density, "liquid"-like regions surrounded by low-density, "gas"-like regions) might be a key factor to better understand water radiolysis near or above tc. It is proposed here to use MD simulations to generate molecularly detailed configurations of SCW at different selected temperatures over a wide range of densities from very dilute vapor to dense SCW, in combination with MC simulations i) to describe the radiolysis of SCW under these specific configurations and ii) to quantitatively determine the yields of all radiolytic species for temperatures up to 625 oC. A number of tests of validity of the codes that are being developed will be carried out, including the influence of key parameters: LET, pH, added solutes (H2 and other .OH scavengers, dissolved O2), high dose rate, etc.). The resulting data will be key inputs into the development of a water chemistry control strategy for the Canadian SCW reactor, defining the oxidizing power of the coolant at various locations in the core. These data will also be of great value for the interpretation of the results of upcoming tests using in-core SCW loops in the Czech Republic.

在目前的压水堆（~250-330 oC，10 MPa）和未来的第四代超临界水反应堆（~430-625 oC，25 MPa）的运行条件下，水的辐解仍然是未知的。在如此高的温度和压力下，特别是超过水的临界点（H2O：tc ~ 373.95 oC，pc ~ 22.06 MPa）的直接测量是困难的，计算机模拟是一个重要的研究途径。这项工作的目的是获得辐射（快中子，γ射线，反冲质子/Oq+离子，q = 1-8）对反应堆堆芯含水系统的影响的增强理解，以指定化学控制策略，最大限度地减少反应堆组件的腐蚀和降解，这些反应堆组件由氧化物质（如.OH，H2 O2，O2和O2）的辐射分解形成。HO2..我们的长期目标是开发一个基准的SCW反应堆辐解模型使用耦合分子动力学（MD）和蒙特-卡罗（MC）模拟。该项目是基于初步结果（在我们的实验室中获得），这表明SCW的异质分子结构（高密度，“液体”状区域周围的低密度，“气体”状区域）可能是一个关键因素，以更好地了解水辐解附近或以上的TC。本文提出利用分子动力学模拟在从非常稀的蒸汽到致密的SCW的广泛密度范围内在不同的选定温度下生成SCW的分子详细构型，结合MC模拟i）描述SCW在这些特定构型下的辐解，ii）定量确定温度高达625 oC的所有辐解物种的产率。将对正在开发的代码的有效性进行一些测试，包括关键参数的影响：LET，pH值，添加的溶质（H2和其他.OH清除剂，溶解的O2），高剂量率等。由此产生的数据将成为加拿大超临界水反应堆水化学控制策略开发的关键投入，确定堆芯不同位置冷却剂的氧化能力。这些数据对于解释即将在捷克共和国使用堆芯SCW回路进行的测试结果也将具有重要价值。