Abstract

Analysis of the experience gained in operating atomic icebreakers, the specifics of operating equipment of the first circuit, and the organization of the water-chemical regime shows the relationship between the high content of gases in the coolant and the problems of ensuring reliable equipment operation. Spatial modeling of vapor-gas bubbles’ mass transfer in the SG-28 steam generator during damping confirmed the possibility of forming a gas cushion in the stagnant zone of the SG. The abrupt increase in the volumetric content of hydrogen during the transition from the liquid to the gas phase of the water coolant explains the anomalous hydrogenation in the area of weld no. 62 on the tubing of the AO SKBK design steam generators. The multiscale, multiphysical approach to conducting calculations was based on the adaptive use of different calculation codes in accordance with the required degree of analysis detail. Four computational models were developed—a common one based on the Relap5 code and three for the CFD code. An offline scheme of combining codes was used. Within its framework, a consistent decomposition of the general problem into computational domains was carried out; appropriate models for them were used, and organization of information exchange between models was based on the initial and boundary conditions. An analysis of the operating conditions and the nature of the mass transfer of vapor-gas bubbles, taking into account the patterns of their fragmentation, confirms the possibility of their entry into the active zone in transient conditions. The presence of oxygen in vapor-gas bubbles dramatically changes the corrosive environment and can cause the nodular corrosion of zirconium shells. To drastically reduce the content of noncondensable gases in the coolant of the first circuit, it was proposed to study the possibility of using a steam volume pressurizer instead of a gas pressurizer in promising projects of transport nuclear power plants (NPPs).

中文翻译：

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原子破冰船反应堆装置中I回路的水化学模式特征和设备运行问题

摘要

通过对运行原子破冰船的经验，第一回路运行设备的详细信息以及水化学体系的组织进行分析，可以看出冷却液中高含量气体与确保设备可靠运行之间的关系。阻尼过程中SG-28蒸汽发生器中蒸汽气泡传质的空间模型确定了在SG的停滞区内形成气垫的可能性。在水冷却剂从液相到气相的过渡过程中，氢的体积含量突然增加，这解释了焊缝区域氢化的异常。AO SKBK设计的蒸汽发生器的管路上的62。多尺度 进行计算的多物理方法是根据所需的分析细节程度，自适应使用不同的计算代码。开发了四个计算模型-一个常见的基于Relap5代码的模型，另外三个用于CFD代码。使用了组合代码的离线方案。在其框架内，将一般性问题统一分解为计算领域。使用了适合他们的模型，并且模型之间的信息交换的组织是基于初始条件和边界条件的。对运行条件和汽泡传质性质的分析，考虑到其破碎模式，确认了在瞬态条件下其进入活性区的可能性。蒸汽气泡中氧气的存在会极大地改变腐蚀环境，并可能导致锆壳的结节腐蚀。为了大幅度减少第一回路的冷却液中不可冷凝气体的含量，建议研究在有希望的运输核电站（NPPs）项目中使用蒸汽量加压器代替气体加压器的可能性。