Aqueous Chemistry of Fission Products under Supercritical Water Reactor Coolant Conditions

该提案旨在为一个合作项目的第二阶段寻求资金，该项目使用最先进的仪器来确定拟议的第四代超临界水冷却核反应堆（“SCWR”）将遇到的极端条件下简单酸，碱，溶解金属和金属络合物的化学平衡常数。 仪器方法包括拉曼和紫外可见光谱;交流电导;和可视化技术;支持从头计算。 这些都是非常专业的高精度设备，具有北美其他实验室所共有的能力，专为在超临界水反应堆运行条件下进行定量测量而建造。 该项目的第一阶段包括建造用于在超临界区域运行的高压电池和新型仪器。 完成了对铜、镍和钴络合物的理论和拉曼研究，以及对锶离子配对的新型电导率研究，温度高达350 °C。 第二阶段将把这些研究扩展到更多的裂变产物种类、铀酰络合物和临界点以上的温度（T > 373 °C）。 将开发半经验方程，以预测这些和其他含水物质在与第四代蒸汽发生器化学相关的极端条件下的行为。待研究的离子包括铯、锶、三价镧系元素裂变产物离子（Pr 3+、Y3+或Ce 3+）、碘化物、高锝酸盐（作为其替代稳定同位素，过锝酸盐）;以及它们与污染物物种和可能的pH控制剂的反应产物。

This proposal seeks funding for the second phase of a collaborative project that uses state-of-the-art instruments to determine chemical equilibrium constants for simple acids, bases, dissolved metals, and metal complexes under the extreme conditions that will be encountered in the proposed Generation IV supercritical-water-cooled nuclear reactor ("SCWR"). The instrumental methods include Raman and UV-visible spectroscopy; AC conductance; and visualization techniques; supported by ab initio computations. These are extremely specialized pieces of high-precision equipment, with capabilities shared by few other laboratories in North America, constructed for the specific purpose of making quantitative measurements under SCWR operating conditions. The first phase of the project included the construction of high-pressure cells and novel instruments for operation in the supercritical region. Theoretical and Raman studies on copper, nickel and cobalt complexes, and novel conductivity studies on strontium ion pairing up to 350 °C were completed. The second phase will extend these studies to more fission-product species; to uranyl complexes; and to temperatures above the critical point (T > 373 °C). Semi-empirical equations will be developed to predict the behaviour of these and other aqueous species under the extreme conditions relevant to Gen IV steam generator chemistry. The ions to be studied include cesium, strontium, a trivalent lanthanide fission-product ion (Pr3+, Y3+ or Ce3+) , iodide, pertechnetate (as its surrogate stable isotope, perrhenate); and their reaction products with contaminant species and possible pH control agents.