Reaction Kinetics in Supercritical Water as Probed with Muonium

我们建议使用μ子自旋光谱研究化学反应在过热水中的超临界水冷却核反应堆（SCWR）设想的整个温度和压力范围内。在这样的实验中，我们使用μ 鎓（Mu）作为原子氢（H）的替代物;在化学上，Mu可以被视为H的轻同位素。位于公元前温哥华的TRIUMF，是世界上仅有的四个拥有适合此类工作的强μ子束的地点之一。在GenIV项目的第一阶段，我们扩展了我们以前在过热水中双分子反应的Mu衰变动力学方面的工作：速率常数随着温度的升高而呈现出一个宽的最大值，低于临界点，然后在压缩性最大值处出现一个尖锐的最小值。设计和制造了一种新的靶细胞，以将研究扩展到650°C。在恒定压力（例如25 MPa）下，水的密度从300°C下的亚临界液体下降到650°C下的超临界流体福尔斯十倍。我们将特别注意氢与水的反应，因为这是高温下氢气的主要来源，并且是SCWR化学控制策略发展的关键反应。

We propose to use muon spin spectroscopy to study chemical reactions in superheated water over the full range of temperatures and pressures envisaged for a supercritical-water-cooled nuclear reactor (SCWR). In such experiments we use muonium (Mu) as a surrogate for atomic hydrogen (H); chemically Mu can be viewed as a light isotope of H. TRIUMF, in Vancouver B.C., is one of only four locations in the world with intense muon beams suitable for such work. In phase I of the GenIV project we extended our previous work on Mu decay kinetics of bimolecular reactions in superheated water: rate constants exhibit a broad maximum with increasing temperature below the critical point, followed by a sharp minimum at the compressibility maximum. A new target cell has been designed and fabricated to extend studies to 650°C. At constant pressure (e.g. 25 MPa) the density of water falls by a factor of ten from the subcritical liquid at 300°C to the supercritical fluid at 650°C. We will pay particular attention to the reaction of H with water, since this is the major source of hydrogen gas at high temperature, and is a key reaction for the development of a chemistry control strategy for the SCWR.