Failure probability analysis of pressure vessels that contain defects under the coupling of inertial force and internal pressure

Very thin cylindrical pressure vessels with torispherical end-closures have been tested under internal pressure until buckles developed in the knuckles of the ends. These were prototype vessels in an austenitic stainless steel. The preparation of the ends and the closed test vessels is outlined, and the instrumentation, test installation, and test procedure are described. Results are given and discussed for three typical ends (diameters 54, 81, and 108in.; thickness to diameter ratios 0.00237, 0.00158, and 0.00119). These include measured thickness and curvature distributions, strain data and the derived elastic stress indices, and pole deflection measurements. Some details of the observed time-dependent plasticity (or ‘cold creep’) are given. Details of two types of buckle that developed eventually in the vessel ends are also reported.

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Failure Probability Assessment for a Boiling Water Reactor Pressure Vessel Under Low Temperature Over-Pressure Event

Volume 7: Operations, Applications and Components ◽

10.1115/pvp2012-78244 ◽

2012 ◽

Author(s):

Hsoung-Wei Chou ◽

Chin-Cheng Huang ◽

Bo-Yi Chen ◽

Hsien-Chou Lin ◽

Ru-Feng Liu

Keyword(s):

Low Temperature ◽

Failure Probability ◽

Pressure Vessel ◽

Fracture Probability ◽

Pressure Vessels ◽

Reactor Pressure Vessel ◽

Boiling Water ◽

Boiling Water Reactor ◽

Water Reactor ◽

Reactor Pressure

The fracture probability of a boiling water reactor pressure vessel for a domestic nuclear power plant in Taiwan has been numerically analyzed using an advanced version of ORNL’s FAVOR code. First, a model of the vessel beltline region, which includes all shell welds and plates, is built for the FAVOR code based on the plant specific parameters of the reactor pressure vessel. Then, a novel flaw model which describes the flaw types of surface breaking flaws, embedded weld flaws and embedded plate flaws are simulated along both inner and outer vessel walls. When conducting the fracture probability analyses, a transient low temperature over-pressure event, which has previously been shown to be the most severe challenge to the integrity of boiling water reactor pressure vessels, is considered as the loading condition. It is found that the fracture occurs in the fusion-line area of axial welds, but with only an insignificant failure probability. The low through-wall cracking frequency indicates that the analyzed reactor pressure vessel maintains sufficient stability until either the end-of-license or for doubling of the present license of operation.

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A Noncyclic Method for Determination of Accumulated Strain in Stainless Steel 304 Pressure Vessels

Journal of Pressure Vessel Technology ◽

10.1115/1.4026940 ◽

2014 ◽

Vol 136 (6) ◽

Author(s):

Gongfeng Jiang ◽

Gang Chen ◽

Liang Sun ◽

Yiliang Zhang ◽

Xiaoliang Jia ◽

...

Keyword(s):

Stainless Steel ◽

Internal Pressure ◽

Pressure Vessel ◽

Peak Stress ◽

Pressure Vessels ◽

Experimental Results ◽

Elastic Domain ◽

Ratcheting Strain ◽

Stainless Steel 304 ◽

Accumulated Strain

Experimental results of uniaxial ratcheting tests for stainless steel 304 (SS304) under stress-controlled condition at room temperature showed that the elastic domain defined in this paper expands with accumulation of plastic strain. Both ratcheting strain and viscoplastic strain rates reduce with the increase of elastic domain, and the total strain will be saturated finally. If the saturated strain and corresponded peak stress of different experimental results under the stress ratio R ≥ 0 are plotted, a curve demonstrating the material shakedown states of SS304 can be constituted. Using this curve, the accumulated strain in a pressure vessel subjected to cyclic internal pressure can be determined by only an elastic-plastic analysis, and without the cycle-by-cycle analysis. Meanwhile, a physical experiment of a thin-walled pressure vessel subjected to cyclic internal pressure has been carried out to verify the feasibility and effectiveness of this noncyclic method. By comparison, the accumulated strains evaluated by the noncyclic method agreed well with those obtained from the experiments. The noncyclic method is simpler and more practical than the cycle-by-cycle method for engineering design.

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A Single Technically Consistent Design Formula for the Thickness of Cylindrical Sections Under Internal Pressure

Journal of Pressure Vessel Technology ◽

10.1115/1.2389035 ◽

2006 ◽

Vol 129 (1) ◽

pp. 211-215 ◽

Cited By ~ 2

Author(s):

John D. Fishburn

Keyword(s):

Experimental Data ◽

Internal Pressure ◽

State Of The Art ◽

Original Data ◽

Pressure Vessels ◽

Time Dependent ◽

Design Codes ◽

Recent Developments ◽

Current Design ◽

Single Formula

Within the current design codes for boilers, piping, and pressure vessels, there are many different equations for the thickness of a cylindrical section under internal pressure. A reassessment of these various formulations, using the original data, is described together with more recent developments in the state of the art. A single formula, which can be demonstrated to retain the same design margin in both the time-dependent and time-independent regimes, is shown to give the best correlation with the experimental data and is proposed for consideration for inclusion in the design codes.

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