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.

目前的加压水冷堆（~250-330 oC，10 MPa）和未来第四代超临界水堆（~430-625 oC，25 MPa）运行条件下水的辐射分解仍然很大程度上未知。在如此高的温度和压力下进行直接测量，特别是超过水的临界点（H2O：tc ~ 373.95 oC，pc ~ 22.06 MPa）是很困难的，计算机模拟是一个重要的研究途径。这项工作的目的是加深对辐射（快中子、伽马射线、反冲质子/Oq+离子，q = 1-8）对反应堆堆芯中水系统的影响的了解，以便指定化学控制策略，最大限度地减少由于氧化物质（如.OH、H2O2、O2和O2）的辐射分解形成而导致的反应堆组件的腐蚀和降解。 O2.-/HO2.. 我们的长期目标是使用耦合分子动力学 (MD) 和蒙特卡罗 (MC) 模拟开发基准 SCW 反应器辐射分解模型。该项目基于（在我们实验室获得的）初步结果，这些结果表明SCW的异质分子结构（高密度“液体”状区域被低密度“气体”状区域包围）可能是更好地了解接近或高于TC的水辐射分解的关键因素。这里建议使用 MD 模拟在从非常稀的蒸气到稠密的 SCW 的各种密度下，在不同的选定温度下生成 SCW 的分子详细配置，并结合 MC 模拟 i) 描述这些特定配置下 SCW 的辐射分解，以及 ii) 定量确定温度高达 625 oC 时所有辐射分解物质的产量。将对正在开发的代码的有效性进行多项测试，包括关键参数的影响：LET、pH、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输入，定义堆芯各个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 环路进行的测试结果也具有重要价值。