PSI - Issue 79

Lazar Jeremić et al. / Procedia Structural Integrity 79 (2026) 117 – 123

123

Likelihood

1

2

3

4

5

Very small

Small

Modest

High

Very high

1

Defect 1.1 advanced UT

2

3 4

Consequence

5 Defect 1.1 conven. UT Figure 10. Risk matrix for defect 1.1 obtained by conventional and by advanced UT

6. Conclusions Based on presented results, one can conclude the following: 

Risk based analysis using FAD to assess likelihood of failure is useful engineering tool in decision making processes to prevent failure of a component with unacceptable defects, since it provides reliable data for management to make a decision about further use of the equipment. In the case of pressure vessel PV 971 one should notice that it has been operating safely in the meantime and finally replaced this year during reconstruction of the whole plant.  In addition, relatively simple FEM is essential to get precise insight in stress and strain distribution in presence of cracks. Combined with the risk-based analysis, it completes reliable judgement to prevent failure. Acknowledgements This work is supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia (Contract No. 451-03-68/2025-14/200135 and. 451-03-68/2025-14/200213). References 1. Golubovi ć , T., Sedmak, A., Spasojevi ć Brki ć , V., Kirin, S., Rakonjac, I., (2018), Novel risk-based assessment of pressure vessels integrity. Technical Gazette 25(3), 803-807 2. Vu č eti ć , I. Kirin, S., Vu č eti ć , T., Golubovi ć , T., Sedmak, A., (2018), Risk Analysis in the Case of Air Storage Tank Failure at RHPP Bajina Bašta, Structural Integrity and Life, 18(1), p. 3-6 3. Mirjana Opa č i ć , Simon Sedmak, Aleksandar Sedmak, Lazar Jeremi ć , Nikola Milovanovi ć , (2024), Integrity assessment of a crack inside a pressure vessel wall in RHPP “Bajina Bašta”, Procedia Structural Integrity, 58, 87-94 4. Mirjana Opa č i ć , Aleksandar Sedmak, Gordana Baki ć , Nenad Miloševi ć , Nikola Milovanovic, (2022), Application of advanced NDT methods to assess structural integrity of pressure vessel welded joints, Procedia Structural Integrity, 42, 1185-1189 5. Abubakr M. Kraedegh, Lazar Jeremi ć , Igor Marti ć , Tamara Golubovi ć , Aleksandar Jovanovi ć , Integrity and risk assessment of offshore jacket structures, Structural Integrity and Life, Vol.24, No.3, 2024, pp. 380–385 6. Anderson, T.L., Fracture Mechanics: Fundamentals and Applications, 4th Edition, CRC Press, 2017 7. Gubeljak, N., Zerbst, U., Predan, J., Oblak, M., (2004), Application of the European SINTAP procedure to the failure analysis of a broken forklift, Engineering Failure Analysis, 11(1), 33-47 8. EN ISO 11666:2018, Non-destructive testing of welds - Ultrasonic testing - Acceptance levels. 9. Hrivnak, I., (1988), Breakdown and repair of large spherical containers for liquefied hydrocarbon gases, IIW Doc. IX-1516-88, Bratislava, 1988 10.H. Kurz, A. Jüngert, S. Dugan, G. Dobmann, C. Boller, (2013), Reliability Considerations of NDT by Probability of Detection (POD) Determination Using Ultrasound Phased Array, Engineering Failure Analysis, 35, 609-617. 10.1016/j.engfailanal.2013.06.008 11.Opacic, M., Integrity assessment of welded joints with unacceptable defects, doctoral thesis (in Serbian), Faculty of Mechanical Engineering, University of Belgrade, 2023 12. https://www.3ds.com/products/simulia/abaqus