Nagy Richárd, Király Márton, Szepesi Tamás, Nagy Attila G, Almási Ádám
Centre for Energy Research, Hungarian Academy of Sciences, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary.
Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary.
Rev Sci Instrum. 2018 Dec;89(12):125114. doi: 10.1063/1.5045461.
During the last decades, several experiments revealed interesting details about the ballooning and burst of nuclear cladding tubes in accident conditions involving high temperature and high pressure. A new set of experiments was conducted at MTA EK to further improve our understanding of this phenomenon. The research goal was to determine the pressure of the burst at different temperatures. These data represent a durability and usability limit of fuel cladding tubes under loss of coolant accident conditions. A large tube furnace was fitted with two optical telescopes on opposite sides to observe the ballooning and burst of zirconium alloy fuel cladding samples. These telescopes gave an opportunity to capture the ballooning and also to use a high-speed camera to record details of the crack formation and crack propagation during the burst. A precise pressurization system was constructed to feed high-pressure argon into the samples at a given pressurization rate. The previous data were reproduced accurately in this new apparatus with further insight into the phenomena. The change in tube diameter was observed using regular HD cameras. Based on the captured images, an algorithmic method was developed to separate the contours of the cladding tubes from the background and the diameter increase was measured. It was found to be mostly uniform at lower pressures. The formation of a bulge started at 85% of actual burst pressure. Crack formation at high temperature was recorded using a high-speed camera at speeds up to 100.000 fps. The details of the planning, facility construction, and gauge calibration are detailed in this article.
在过去几十年里，多项实验揭示了在涉及高温高压的事故条件下核包壳管膨胀和破裂的有趣细节。匈牙利科学院能源研究中心开展了一组新的实验，以进一步加深我们对这一现象的理解。研究目标是确定不同温度下的破裂压力。这些数据代表了冷却剂丧失事故条件下燃料包壳管的耐久性和可用性极限。一个大型管式炉在相对两侧安装了两个光学望远镜，用于观察锆合金燃料包壳样品的膨胀和破裂情况。这些望远镜提供了捕捉膨胀情况的机会，还能利用高速摄像机记录破裂过程中裂纹形成和扩展的细节。构建了一个精确的加压系统，以给定的加压速率向样品中注入高压氩气。在这个新装置中准确再现了先前的数据，并对这些现象有了更深入的了解。使用普通高清摄像机观察管直径的变化。基于捕获的图像，开发了一种算法方法，将包壳管的轮廓与背景分离，并测量直径的增加。发现在较低压力下直径增加大多是均匀的。在实际破裂压力的85%时开始形成鼓包。使用高速摄像机以高达100000帧/秒的速度记录高温下的裂纹形成情况。本文详细介绍了实验规划、设施建设和仪表校准的细节。
