### Abstract

Original language | English |
---|---|

Pages (from-to) | 90-96 |

Number of pages | 7 |

Journal | Reliability Engineering and System Safety |

Volume | 105 |

DOIs | |

Publication status | Published - 2012 |

MoE publication type | A1 Journal article-refereed |

Event | European Safety and Reliability Conference, ESREL 2010 - Rhodes, Greece Duration: 5 Sep 2010 → 9 Sep 2010 |

### Fingerprint

### Keywords

- Inspection reliability
- probabilistic fracture mechanics (PFM)
- probability of detection curves (POD)
- risk-informed in-service inspection

### Cite this

*Reliability Engineering and System Safety*,

*105*, 90-96. https://doi.org/10.1016/j.ress.2012.03.012

}

*Reliability Engineering and System Safety*, vol. 105, pp. 90-96. https://doi.org/10.1016/j.ress.2012.03.012

**A study on the effect of flaw detection probability assumptions on risk reduction achieved by non-destructive inspection.** / Cronvall, Otso (Corresponding Author); Simola, Kaisa; Männistö, Ilkka; Gunnars, J.; Alverlind, L.; Dillström, P.; Gandossi, L.

Research output: Contribution to journal › Article › Scientific › peer-review

TY - JOUR

T1 - A study on the effect of flaw detection probability assumptions on risk reduction achieved by non-destructive inspection

AU - Cronvall, Otso

AU - Simola, Kaisa

AU - Männistö, Ilkka

AU - Gunnars, J.

AU - Alverlind, L.

AU - Dillström, P.

AU - Gandossi, L.

PY - 2012

Y1 - 2012

N2 - Leakages and ruptures of piping components lead to reduction or loss of the pressure retaining capability of the system, and thus contribute to the overall risk associated with nuclear power plants. In-service inspection (ISI) aims at verifying that defects are not present in components of the pressure boundary or, if defects are present, ensuring that these are detected before they affect the safe operation of the plant. Reliability estimates of piping are needed e.g., in probabilistic safety assessment (PSA) studies, risk-informed ISI (RI-ISI) applications, and other structural reliability assessments. Probabilistic fracture mechanics models can account for ISI reliability, but a quantitative estimate for the latter is needed. This is normally expressed in terms of probability of detection (POD) curves, which correlate the probability of detecting a flaw with flaw size. A detailed POD curve is often difficult (or practically impossible) to obtain. If sufficient risk reduction can be shown by using simplified (but reasonably conservative) POD estimates, more complex PODs are not needed. This paper summarises the results of a study on the effect of piping inspection reliability assumptions on failure probability using structural reliability models. The main interest was to investigate whether it is justifiable to use a simplified POD curve. Further, the study compared various structural reliability calculation approaches for a set of analysis cases. The results indicate that the use of a simplified POD could be justifiable in RI-ISI applications.

AB - Leakages and ruptures of piping components lead to reduction or loss of the pressure retaining capability of the system, and thus contribute to the overall risk associated with nuclear power plants. In-service inspection (ISI) aims at verifying that defects are not present in components of the pressure boundary or, if defects are present, ensuring that these are detected before they affect the safe operation of the plant. Reliability estimates of piping are needed e.g., in probabilistic safety assessment (PSA) studies, risk-informed ISI (RI-ISI) applications, and other structural reliability assessments. Probabilistic fracture mechanics models can account for ISI reliability, but a quantitative estimate for the latter is needed. This is normally expressed in terms of probability of detection (POD) curves, which correlate the probability of detecting a flaw with flaw size. A detailed POD curve is often difficult (or practically impossible) to obtain. If sufficient risk reduction can be shown by using simplified (but reasonably conservative) POD estimates, more complex PODs are not needed. This paper summarises the results of a study on the effect of piping inspection reliability assumptions on failure probability using structural reliability models. The main interest was to investigate whether it is justifiable to use a simplified POD curve. Further, the study compared various structural reliability calculation approaches for a set of analysis cases. The results indicate that the use of a simplified POD could be justifiable in RI-ISI applications.

KW - Inspection reliability

KW - probabilistic fracture mechanics (PFM)

KW - probability of detection curves (POD)

KW - risk-informed in-service inspection

U2 - 10.1016/j.ress.2012.03.012

DO - 10.1016/j.ress.2012.03.012

M3 - Article

VL - 105

SP - 90

EP - 96

JO - Reliability Engineering and System Safety

JF - Reliability Engineering and System Safety

SN - 0951-8320

ER -