# Evaluations of Structural Failure Probabilities and Candidate Inservice Inspection Programs

## Abstract

The work described in this report applies probabilistic structural mechanics models to predict the reliability of nuclear pressure boundary components. These same models are then applied to evaluate the effectiveness of alternative programs for inservice inspection to reduce these failure probabilities. Results of the calculations support the development and implementation of risk-informed inservice inspection of piping and vessels. Studies have specifically addressed the potential benefits of ultrasonic inspections to reduce failure probabilities associated with fatigue crack growth and stress-corrosion cracking. Parametric calculations were performed with the computer code pc-PRAISE to generate an extensive set of plots to cover a wide range of pipe wall thicknesses, cyclic operating stresses, and inspection strategies. The studies have also addressed critical inputs to fracture mechanics calculations such as the parameters that characterize the number and sizes of fabrication flaws in piping welds. Other calculations quantify uncertainties associated with the inputs calculations, the uncertainties in the fracture mechanics models, and the uncertainties in the resulting calculated failure probabilities. A final set of calculations address the effects of flaw sizing errors on the effectiveness of inservice inspection programs.

- Authors:

- Publication Date:

- Research Org.:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 974009

- Report Number(s):
- NUREG/CR-6986; PNNL-13810

401001060; TRN: US1002168

- DOE Contract Number:
- AC05-76RL01830

- Resource Type:
- Technical Report

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 22 GENERAL STUDIES OF NUCLEAR REACTORS; 42 ENGINEERING; REACTOR COMPONENTS; PRESSURE VESSELS; MATHEMATICAL MODELS; RELIABILITY; IN-SERVICE INSPECTION; PIPES; CRACK PROPAGATION; DEFECTS; FRACTURE MECHANICS; STRESS CORROSION; ULTRASONIC TESTING; FATIGUE; WELDED JOINTS

### Citation Formats

```
Khaleel, Mohammad A, and Simonen, Fredric A.
```*Evaluations of Structural Failure Probabilities and Candidate Inservice Inspection Programs*. United States: N. p., 2009.
Web. doi:10.2172/974009.

```
Khaleel, Mohammad A, & Simonen, Fredric A.
```*Evaluations of Structural Failure Probabilities and Candidate Inservice Inspection Programs*. United States. doi:10.2172/974009.

```
Khaleel, Mohammad A, and Simonen, Fredric A. Fri .
"Evaluations of Structural Failure Probabilities and Candidate Inservice Inspection Programs". United States. doi:10.2172/974009. https://www.osti.gov/servlets/purl/974009.
```

```
@article{osti_974009,
```

title = {Evaluations of Structural Failure Probabilities and Candidate Inservice Inspection Programs},

author = {Khaleel, Mohammad A and Simonen, Fredric A},

abstractNote = {The work described in this report applies probabilistic structural mechanics models to predict the reliability of nuclear pressure boundary components. These same models are then applied to evaluate the effectiveness of alternative programs for inservice inspection to reduce these failure probabilities. Results of the calculations support the development and implementation of risk-informed inservice inspection of piping and vessels. Studies have specifically addressed the potential benefits of ultrasonic inspections to reduce failure probabilities associated with fatigue crack growth and stress-corrosion cracking. Parametric calculations were performed with the computer code pc-PRAISE to generate an extensive set of plots to cover a wide range of pipe wall thicknesses, cyclic operating stresses, and inspection strategies. The studies have also addressed critical inputs to fracture mechanics calculations such as the parameters that characterize the number and sizes of fabrication flaws in piping welds. Other calculations quantify uncertainties associated with the inputs calculations, the uncertainties in the fracture mechanics models, and the uncertainties in the resulting calculated failure probabilities. A final set of calculations address the effects of flaw sizing errors on the effectiveness of inservice inspection programs.},

doi = {10.2172/974009},

journal = {},

number = ,

volume = ,

place = {United States},

year = {2009},

month = {5}

}