One of the major factors affecting the life span of a Reactor Pressure Vessel (RPV) is the Pressurised Thermal Shock (PTS). PTS is a thermo-mechanical load on the RPV wall due to steep temperature gradients and structural load created by internal pressure of the fluid within the RPV. Safe operating life of a nuclear power plant is ensured by carrying out fracture analysis of the RPV against thermal shock. Carrying out fracture tests on RPV/large scale components is not always feasible. Hence, studies on laboratory level specimens are necessary to validate and supplement the prototype results. This paper aims to study the fracture behaviour of standard Compact Tension [C(T)] specimens, made of RPV steel 20MnMoNi55, subjected to thermal shock through experimental and numerical investigations. Fracture tests have been carried out on the C(T) specimens subjected to thermal transient load and tensile load to quantify the effect of thermal shock. Crack resistance curves are obtained from the fracture tests as per ASTM E1820 and compared with those obtained numerically using XFEM and a good agreement was found. A quantitative study on the crack tip plastic zone, computed using cohesive segment approach, from the numerical analyses justified the experimental crack initiation toughness.

影响反应堆压力容器 (RPV) 寿命的主要因素之一是加压热冲击 (PTS)。由于陡峭的温度梯度和由 RPV 内流体的内部压力产生的结构载荷，PTS 是 RPV 壁上的热机械载荷。通过对 RPV 进行热冲击断裂分析，确保核电厂的安全运行寿命。对 RPV/大型组件进行断裂测试并不总是可行的。因此，有必要对实验室级标本进行研究以验证和补充原型结果。本文旨在通过实验和数值研究，研究由 RPV 钢 20MnMoNi55 制成的标准紧凑拉伸 [C(T)] 试样在热冲击下的断裂行为。对承受热瞬态载荷和拉伸载荷的 C(T) 试样进行了断裂试验，以量化热冲击的影响。抗裂性曲线是根据 ASTM E1820 从断裂试验中获得的，并与使用 XFEM 数值获得的曲线进行比较，发现了良好的一致性。对裂纹尖端塑性区的定量研究，使用内聚段方法计算，从数值分析证明实验裂纹起始韧性是合理的。