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Published in: Strength of Materials 5/2021

13-01-2022

Comparative Analysis of Irradiation Swelling Models for the Stress-Strain State Evaluation of the WWER-1000 Baffle

Authors: O. V. Makhnenko, S. M. Kandala, E. M. Savyts’ka

Published in: Strength of Materials | Issue 5/2021

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Abstract

Assessment of the service life of internal devices operating under the influence of ionizing radiation is the actual task for prolongating safe operation of WWER-1000 NPP power units. It is necessary to take into account such physical processes as irradiation swelling and irradiation creep, which for a long-term operation can significantly affect the distortions and structural integrity of the internals. The comparative evaluation of irradiation swelling in the material of the internal baffle of the WWER-1000 reactor, obtained as a result of mathematical modeling by various known models of irradiation swelling in 08Cr18Ni10Ti austenitic steel and its analog AISI 304, was conducted. Four physical models are considered, which take into account neutron dose, dose rate, irradiative temperature, stress state and the irradiation creep of the baffle material. For all considered models, the effect of these factors on predicted irradiation swelling in the baffle after long-term operation up to 60 years is analyzed. The results of the comparative analysis showed that in models that do not take into account the process of irradiation creep, the maximum stresses in the baffle can reach the yield strength of the irradiated material (up to 800 MPa), and this will contribute to excessive conservatism in assessing the strength of internals. The model regulated by NNEGC “Energoatom” for computational evaluation of irradiation swelling in internals, taking into account the accumulated dose, irradiation temperature, stress state, and process of radiation creep in the material, is rather conservative and correlates well with the results of other models in the range of input parameters, which are characteristic for operating modes of the WWER-1000 power units, namely, in the range of maximum temperatures of the baffle material 380–390°C and the accumulated dose for 60 years of operation is not more than 120 dpa.
Literature
1.
go back to reference PM-T.0.03.333-15. Typical Program of Assessing the Technical State and Extending the Operating Lifetime of WWER-1000 Reactor Internals [in Russian]. PM-T.0.03.333-15. Typical Program of Assessing the Technical State and Extending the Operating Lifetime of WWER-1000 Reactor Internals [in Russian].
2.
go back to reference B. A. Boley and J. H. Weiner, Theory of Thermal Stresses, John Wiley and Sons, Inc., New York (1960). B. A. Boley and J. H. Weiner, Theory of Thermal Stresses, John Wiley and Sons, Inc., New York (1960).
3.
go back to reference V. L. Rvachev (Ed.), A. N. Podgornyi, P. P. Gontarovskyi, et al., Problems of Contact Interaction of Structural Elements [in Russian], Naukova Dumka, Kiev (1989). V. L. Rvachev (Ed.), A. N. Podgornyi, P. P. Gontarovskyi, et al., Problems of Contact Interaction of Structural Elements [in Russian], Naukova Dumka, Kiev (1989).
4.
go back to reference S. N. Votinov, V. I. Prokhorov, and Z. Å. Ostrovskii, Irradiated Stainless Steels [in Russian], Nauka, Moscow (1987). S. N. Votinov, V. I. Prokhorov, and Z. Å. Ostrovskii, Irradiated Stainless Steels [in Russian], Nauka, Moscow (1987).
5.
go back to reference O. K. Chopra, Degradation of LWR Core Internal Materials due to Neutron Irradiation, Environmental Science Division Argonne National Laboratory, Argonne (2010), pp. 81–89. O. K. Chopra, Degradation of LWR Core Internal Materials due to Neutron Irradiation, Environmental Science Division Argonne National Laboratory, Argonne (2010), pp. 81–89.
6.
go back to reference O. S. Kalchenko, V. V. Bryk, V. M. Voyevodin, and M. P. Lazarev, “Prediction of radiation swelling of WWER-1000 reactors baffle ring for service life up to 30–60 years,” Nucl. Phys. Atom. Energy, 12, Issue 1, 69–77 (2011). O. S. Kalchenko, V. V. Bryk, V. M. Voyevodin, and M. P. Lazarev, “Prediction of radiation swelling of WWER-1000 reactors baffle ring for service life up to 30–60 years,” Nucl. Phys. Atom. Energy, 12, Issue 1, 69–77 (2011).
7.
go back to reference I. V. Mirzov, Stress Strain State of WWER-1000 Reactor Internals [in Russian], Author’s Abstract of the Candidate Degree Thesis (Tech. Sci.), Paton Electric Welding Institute of the National Academy of Sciences of Ukraine, Kiev (2015). I. V. Mirzov, Stress Strain State of WWER-1000 Reactor Internals [in Russian], Author’s Abstract of the Candidate Degree Thesis (Tech. Sci.), Paton Electric Welding Institute of the National Academy of Sciences of Ukraine, Kiev (2015).
9.
go back to reference VERLIFE-2012, Annex G to Appendix C. Integrity and Lifetime Assessment Procedure of RPV Internals in WWER NPPS during Operation, pp. 63–64. VERLIFE-2012, Annex G to Appendix C. Integrity and Lifetime Assessment Procedure of RPV Internals in WWER NPPS during Operation, pp. 63–64.
10.
go back to reference B. Margolin, V. Fedorova, A. Sorokin, et al., “The mechanisms of material degradation under neutron irradiation for WWER internals and methods for structural integrity assessment,” in: Proc. of the Int. Conf. on Structural Integrity and Life of NPP Equipment (October 1–5, 2012, Kiev, Ukraine). B. Margolin, V. Fedorova, A. Sorokin, et al., “The mechanisms of material degradation under neutron irradiation for WWER internals and methods for structural integrity assessment,” in: Proc. of the Int. Conf. on Structural Integrity and Life of NPP Equipment (October 1–5, 2012, Kiev, Ukraine).
11.
go back to reference O. V. Makhnenko and I. V. Mirzov, “Investigation of the stress-strain state of internals using the example of the baffle and the barrel wall of a WWER-1000 reactor,” in: Reliability and Durability of Machines and Structures [in Russian], Issue 37 (2013), pp. 98–110. O. V. Makhnenko and I. V. Mirzov, “Investigation of the stress-strain state of internals using the example of the baffle and the barrel wall of a WWER-1000 reactor,” in: Reliability and Durability of Machines and Structures [in Russian], Issue 37 (2013), pp. 98–110.
12.
go back to reference V. Pištora, M. Švrček, and I. Mirzov, “Fatigue assessment of WWER-1000 core baffle,” in: Trans. of the SMiRT-24 (August 20–25, 2017, BEXCO, Busan, Korea) (2017). V. Pištora, M. Švrček, and I. Mirzov, “Fatigue assessment of WWER-1000 core baffle,” in: Trans. of the SMiRT-24 (August 20–25, 2017, BEXCO, Busan, Korea) (2017).
13.
go back to reference O. V. Makhnenko, S. M. Kandala, and M. V. Cherkashin, “Improving the methods for estimating radiation swelling and progressive dimensional changes of the elements of WWER-1000 internals,” Yader. Radiats. Bezp., No. 2 (82), 38–45 (2019). O. V. Makhnenko, S. M. Kandala, and M. V. Cherkashin, “Improving the methods for estimating radiation swelling and progressive dimensional changes of the elements of WWER-1000 internals,” Yader. Radiats. Bezp., No. 2 (82), 38–45 (2019).
Metadata
Title
Comparative Analysis of Irradiation Swelling Models for the Stress-Strain State Evaluation of the WWER-1000 Baffle
Authors
O. V. Makhnenko
S. M. Kandala
E. M. Savyts’ka
Publication date
13-01-2022
Publisher
Springer US
Published in
Strength of Materials / Issue 5/2021
Print ISSN: 0039-2316
Electronic ISSN: 1573-9325
DOI
https://doi.org/10.1007/s11223-021-00334-7