Analysis of natural circulation types' effect on source term during PWR severe accident

Zarnousheh Farahani, A.; Yousefpour, F.; Nematollahi, M.R.; Pirouzmand, A.

doi:10.24200/nst.2021.968.1655

Document Type : Research Paper

Authors

¹ Department of Nuclear Engineering, Faculty of Mechanical Engineering, Shiraz University, Postalcode: 7193616548, Shiraz – Iran

² Reactor and Nuclear Safety Research School, Nuclear Science and Technology Research Institute, AEOI, P.O.Box: 11365-8486, Tehran – Iran

³ Security Research Center, Shiraz University, Postalcode: 7193616548, Shiraz-Iran

https://doi.org/10.24200/nst.2021.968.1655

Abstract

Creep rupture as a failure mechanism during a severe accident in a PWR is of particular importance as it can lead to releasing radioactive materials into the environment. Following a severe accident, the decay heat transferred to other parts of the reactor cooling system can result in the heat-up of RCS structures and failure of vulnerable pressure boundaries. SBO without operator actions accident (TMLB sequence) is considered one of the most likely scenarios threatening the integrity of the RCS pressure boundary. In addition to PWR plant modeling, in this sequence, the location of rupture in the RCS depends on the type of natural circulation phenomenon of the reactor's primary side. This research investigates the sensitivity analysis of steam generator tube rupture (SGTR) and RCS hot-leg to the type of natural circulation, i.e. con-current and countercurrent, using the MELCOR code. The results of two models of con-current and countercurrent natural circulation show when the countercurrent natural circulation phenomenon is predominant, the RCS hot leg creep rupture occurs earlier than SGTR. However, the SGTR occurs earlier than any other part of RCS due to the concurrent natural circulation phenomenon. Moreover, the amount of materials released to different parts of the plant and the environment has been estimated for both models. The results show that about 18 kg and 145.76 kg of radioactive aerosol and fission product vapor materials are ejected to the containment following the rupture for con-current and countercurrent natural circulation models, respectively. On the other hand, in the con-current natural circulation, about 136.33 kg of radioactive aerosol and fission product vapor materials are released into the environment through the main steam line safety valve.

Keywords

20.1001.1.17351871.1402.44.1.10.0

References

1. S.A. Eide, et al., Reevaluation of Station Blackout Risk at Nuclear Power Plants, Analysis of Loss of Offsite Power Events:1986-2004, NUREG/CR-6890, (U.S.Nuclear Regulatory Commission, Idaho National Laborator, December 2005), Vol. 1.

2. T. Lind, et al., A summary of fission-product-transport phenomena during SGTR severe accidents, J. Nucl. Eng. Des., 363, 110635 (2020).

3. U.S. NRC, Risk assessment of severe accident-induced steam generator tube rupture, NUREG-1570 (U.S. Nuclear Regulatory Commission, Washington DC, 1998).

4. A. Auvinen, et al., Steam generator tube rupture (SGTR) scenarios, J. Nucl. Eng. Des., 235, 457 (2005).

5. Y. Liao, K. Vierow, MELCOR analysis of steam generator tube creep rupture in station blackout severe accident, J. Nucl. Technol., 152(3), 302 (2005).

6. IAEA-TECDOC-1127, A Simplified Approach to Estimating Reference Source Terms for LWR Designs, (International Atomic Energy Agency, Vienna, 1999).

7. S. Güntay, et al., ARTIST: introduction and first results, J. Nucl. Eng. Des., 231(1), 109 (2004).

8. A.Z. Farahani, et al., Sensitivity analysis for thermo-hydraulics model of a Westinghouse type PWR: verification of the simulation results, J. Kerntechnik, 82(3), 1 (2017).

9. R.O. Gauntt, et al., State-of-the-Art Reactor Consequence Analyses Project, MELCOR Best Modeling Practices, NUREG-1935, (U.S. Nuclear Regulatory Commission, Sandia National Laboratories, 2005).

10. K. Vierow, et al., Severe accident analysis of a PWR station blackout with the MELCOR, MAAP4, and SCDAP/RELAP5 codes, J. Nucl. Eng. Des., 234, (1-3), 129 (2004).

11. D. Jian, C. Xuewu, Analysis of hot leg natural circulation under station blackout severe accident, J. Nuc. Sci. and Tech., 18 (2), 123 (2007).

12. C. Peng, Y. Yang, The analysis of severe accident induced steam generator tube rupture and LERF risk, J. Adv. Mat. Res., 614-615, 626 (2013).

13. U.S. NRC Regulatory Guide, RG1.155: Station Blackout, (1988).

14. F. Yousefpour, et al., Development of a Qualified MELCOR Model for IR-360 NPP Using SNAP Software, J. of Nucl Sci. and Tech., 37(4), 42 (2017).

15. F.R. Larson, J. Miller, Transactions ASME, 74, 765 (1952).

16. MASNA Co., SA0042, Verification and Validation (V&V) of Success Criteria Analysis Codes, (2010).

17. IAEA-Safety Reports Series, Approaches and Tools for Severe Accident Analysis for Nuclear Power Plants, Safety reports series, ISSN 1020-6450; no. 56; International Atomic Energy Agency, Vienna: (2008).

18. M. Lee, J.S. Wu, Ex-Vessel Releases of Radionuclides During Molten Core/Concrete Interactions in Severe Light Water Reactor Accidents, J. Nuc. Sci. and Eng., 111, 82 (1992).

Journal of Nuclear Science, Engineering and Technology (JONSAT)

Analysis of natural circulation types' effect on source term during PWR severe accident

References

References

1. S.A. Eide, et al., Reevaluation of Station Blackout Risk at Nuclear Power Plants, Analysis of Loss of Offsite Power Events:1986-2004, NUREG/CR-6890, (U.S.Nuclear Regulatory Commission, Idaho National Laborator, December 2005), Vol. 1.

2. T. Lind, et al., A summary of fission-product-transport phenomena during SGTR severe accidents, J. Nucl. Eng. Des., 363, 110635 (2020).

3. U.S. NRC, Risk assessment of severe accident-induced steam generator tube rupture, NUREG-1570 (U.S. Nuclear Regulatory Commission, Washington DC, 1998).

4. A. Auvinen, et al., Steam generator tube rupture (SGTR) scenarios, J. Nucl. Eng. Des., 235, 457 (2005).

5. Y. Liao, K. Vierow, MELCOR analysis of steam generator tube creep rupture in station blackout severe accident, J. Nucl. Technol., 152(3), 302 (2005).

6. IAEA-TECDOC-1127, A Simplified Approach to Estimating Reference Source Terms for LWR Designs, (International Atomic Energy Agency, Vienna, 1999).

7. S. Güntay, et al., ARTIST: introduction and first results, J. Nucl. Eng. Des., 231(1), 109 (2004).

8. A.Z. Farahani, et al., Sensitivity analysis for thermo-hydraulics model of a Westinghouse type PWR: verification of the simulation results, J. Kerntechnik, 82(3), 1 (2017).

10. K. Vierow, et al., Severe accident analysis of a PWR station blackout with the MELCOR, MAAP4, and SCDAP/RELAP5 codes, J. Nucl. Eng. Des., 234, (1-3), 129 (2004).

11. D. Jian, C. Xuewu, Analysis of hot leg natural circulation under station blackout severe accident, J. Nuc. Sci. and Tech., 18 (2), 123 (2007).

12. C. Peng, Y. Yang, The analysis of severe accident induced steam generator tube rupture and LERF risk, J. Adv. Mat. Res., 614-615, 626 (2013).

13. U.S. NRC Regulatory Guide, RG1.155: Station Blackout, (1988).

14. F. Yousefpour, et al., Development of a Qualified MELCOR Model for IR-360 NPP Using SNAP Software, J. of Nucl Sci. and Tech., 37(4), 42 (2017).

15. F.R. Larson, J. Miller, Transactions ASME, 74, 765 (1952).

16. MASNA Co., SA0042, Verification and Validation (V&V) of Success Criteria Analysis Codes, (2010).

17. IAEA-Safety Reports Series, Approaches and Tools for Severe Accident Analysis for Nuclear Power Plants, Safety reports series, ISSN 1020-6450; no. 56; International Atomic Energy Agency, Vienna: (2008).

Volume 44, Issue 1 - Serial Number 103
April 2023
Pages 78-86

Analysis of natural circulation types' effect on source term during PWR severe accident

References

References

1. S.A. Eide, et al., Reevaluation of Station Blackout Risk at Nuclear Power Plants, Analysis of Loss of Offsite Power Events:1986-2004, NUREG/CR-6890, (U.S.Nuclear Regulatory Commission, Idaho National Laborator, December 2005), Vol. 1.

2. T. Lind, et al., A summary of fission-product-transport phenomena during SGTR severe accidents, J. Nucl. Eng. Des., 363, 110635 (2020).

3. U.S. NRC, Risk assessment of severe accident-induced steam generator tube rupture, NUREG-1570 (U.S. Nuclear Regulatory Commission, Washington DC, 1998).

4. A. Auvinen, et al., Steam generator tube rupture (SGTR) scenarios, J. Nucl. Eng. Des., 235, 457 (2005).

5. Y. Liao, K. Vierow, MELCOR analysis of steam generator tube creep rupture in station blackout severe accident, J. Nucl. Technol., 152(3), 302 (2005).

6. IAEA-TECDOC-1127, A Simplified Approach to Estimating Reference Source Terms for LWR Designs, (International Atomic Energy Agency, Vienna, 1999).

7. S. Güntay, et al., ARTIST: introduction and first results, J. Nucl. Eng. Des., 231(1), 109 (2004).

8. A.Z. Farahani, et al., Sensitivity analysis for thermo-hydraulics model of a Westinghouse type PWR: verification of the simulation results, J. Kerntechnik, 82(3), 1 (2017).

10. K. Vierow, et al., Severe accident analysis of a PWR station blackout with the MELCOR, MAAP4, and SCDAP/RELAP5 codes, J. Nucl. Eng. Des., 234, (1-3), 129 (2004).

11. D. Jian, C. Xuewu, Analysis of hot leg natural circulation under station blackout severe accident, J. Nuc. Sci. and Tech., 18 (2), 123 (2007).

12. C. Peng, Y. Yang, The analysis of severe accident induced steam generator tube rupture and LERF risk, J. Adv. Mat. Res., 614-615, 626 (2013).

13. U.S. NRC Regulatory Guide, RG1.155: Station Blackout, (1988).

14. F. Yousefpour, et al., Development of a Qualified MELCOR Model for IR-360 NPP Using SNAP Software, J. of Nucl Sci. and Tech., 37(4), 42 (2017).

15. F.R. Larson, J. Miller, Transactions ASME, 74, 765 (1952).

16. MASNA Co., SA0042, Verification and Validation (V&V) of Success Criteria Analysis Codes, (2010).

17. IAEA-Safety Reports Series, Approaches and Tools for Severe Accident Analysis for Nuclear Power Plants, Safety reports series, ISSN 1020-6450; no. 56; International Atomic Energy Agency, Vienna: (2008).

Volume 44, Issue 1 - Serial Number 103April 2023Pages 78-86

Volume 44, Issue 1 - Serial Number 103
April 2023
Pages 78-86