Chemistry in near-critical and supercritical water for the generation IV CANDU reactor concept

第四代CANDU反应堆是一种新型的、极其节能的先进反应堆的概念设计，将于2025年投产。第四代概念反应堆将在高达625摄氏度的温度下产生超临界水来发电、氢气和区域供暖。此外，使用超临界水将热量从反应堆核心输送到涡轮机将产生比当前CANDU设计中使用的极端水化学条件多得多的极端水化学条件。第四代CANDU概念的长期可行性取决于设计者预测和控制水化学的能力，以最大限度地减少放射性核素的传输和微妙的腐蚀影响。这项提案寻求为一个合作项目寻求资金，该项目将使用特拉华大学开发的最先进的电导系统，在近临界和超临界条件(300至400摄氏度，30兆帕)下测定简单酸、碱和金属盐的电离和缔合常数。该电导仪器是一种极其专业的高精度设备，是北美仅有的两台具有这种能力的仪器之一。该项目包括升级和校准设备，以改善超临界地区的操作，测量与第四代蒸汽发生器化学有关的几种酸、碱和盐，这项关于第四代反应堆概念的赛前研究，将提高北美在生产符合加拿大专业知识和CANDU经验的第四代反应堆的国际竞争中的效率。短期的好处是(I)对SCWR化学基础的基本了解和(Ii)近临界和超临界系统基础研究的仪器。长期利益是，如果在北美开发该反应堆，将在制造技术方面处于领先地位，显著减少温室气体排放，并节省与44%的效率和联产氢气相关的能源。

The "Generation IV" CANDU reactor is a conceptual design for a novel, extremely energy-efficient  advanced reactor that would come on line in 2025.  The Gen IV concept would produce super-critical water at temperatures as high as 625°C to generate electricity, hydrogen and district heating.   The use of super-critical water to carry heat from the reactor core to the turbine will generate much more extreme water chemistry conditions than those used in current CANDU design, which operates from 250 to 310°C.  The long term viability of the Gen IV CANDU concept depends on the ability of designers to predict and control water chemistry to minimize radionuclide transport and subtle corrosion effects. This proposal seeks funding for a collaborative project that will use a state-of-the-art conductance system, developed at the University of Delaware and now moved to Guelph, to determine ionization and association constants for simple acids, bases and metal salts under near-critical and super-critical conditions (300 to 400°C, and 30 MPa).  The conductance apparatus is an extremely specialized piece of high-precision equipment, one of only two instruments with this capability in North America.  The project includes the upgrading and calibration of the equipment for improved operation in the supercritical region, measurements on several acids, bases and salts relevant to Gen IV steam generator chemistry, and the development of equations to predict the behaviour of aqueous species under these extreme conditions.  This pre-competitive research on Gen IV reactor concept, will advance North American effectiveness in the international competition to produce a Gen IV reactor compatible with Canada's expertise and CANDU experience. The short term benefits are (i)fundamental understanding of SCWR chemistry fundamentals and (ii) instrumentation for basic research on near-critical and super-critical systems. Long term benefits are the leadership in manufacturing technology if the reactor is developed in North America, significant reduction in green house gases,  and the energy savings associated with 44% efficiency and the co-generation of hydrogen.