Phase Composition Study of Corrosion Products at NPP

Slugeň, V.; Lipka, J.; Dekan, Július; Degmova, J.; Toth, I. J.

doi:10.5772/34288

Cited by 2 publications

(2 citation statements)

References 11 publications

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“…The magnetite presence in all samples is almost stoichiometric (ratio Fe 3+ / Fe 2+ tends to 2.0). Results of these analyses are summarized in our previous work [5].…”

Section: Resultsmentioning

confidence: 99%

Application of Mössbauer spectroscopy on corrosion products of NPP

Dekan¹,

Lipka

Slugeň³

2012

Hyperfine Interact

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Steam generator (SG) is generally one of the most important components at all nuclear power plants (NPP) with close impact to safe and long-term operation. Material degradation and corrosion/erosion processes are serious risks for long-term reliable operation. Steam generators of four VVER-440 units at nuclear power plants V-1 and V-2 in Jaslovske Bohunice (Slovakia) were gradually changed by new original "Bohunice" design in period 1994-1998, in order to improve corrosion resistance of SGs. Corrosion processes before and after these design and material changes in Bohunice secondary circuit were studied using Mössbauer spectroscopy during last 25 years. Innovations in the feed water pipeline design as well as material composition improvements were evaluated positively. Mössbauer spectroscopy studies of phase composition of corrosion products were performed on real specimens scrapped from water pipelines or in form of filters deposits. Newest results in our long-term corrosion study confirm good operational experiences and suitable chemical regimes (reduction environment) which results mostly in creation of magnetite (on the level 70 % or higher) and small portions of hematite, goethite or hydrooxides. Regular observation of corrosion/erosion processes is essential for keeping NPP operation on high safety level. The output from performed material analyses influences the optimisation of operating chemical regimes and it can be used in optimisation of regimes at decontamination and passivation of pipelines or secondary circuit components. It can be concluded that a longer passivation time leads more to magnetite fraction in the corrosion products composition.

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“…The magnetite presence in all samples is almost stoichiometric (ratio Fe 3+ / Fe 2+ tends to 2.0). Results of these analyses are summarized in our previous work [5].…”

Section: Resultsmentioning

confidence: 99%

Application of Mössbauer spectroscopy on corrosion products of NPP

Dekan¹,

Lipka

Slugeň³

2012

Hyperfine Interact

Self Cite

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“…As serious damages were observed in the region of the T-junction of the pipe collector and the outlet nozzles after 10 years of operation (the strong erosion caused holes as is visible in Figure 1), the former feed water distributing system was replaced by an advanced system, developed at NPP Jaslovske Bohunice [12,13].…”

Section: Steam Generatormentioning

confidence: 99%

Analysis of Steam Generators Corrosion Products from Slovak NPP Bohunice

Degmova

Dekan

Slugeň

et al. 2012

International Journal of Corrosion

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One of the main goals of the nuclear industry is to increase the nuclear safety and reliability of nuclear power plants (NPPs). As the steam generator (SG) is the most corrosion sensitive component of NPPs, it is important to analyze the corrosion process and optimize its construction materials to avoid damages like corrosion cracking. For this purpose two different kinds of SGs and its feed water distributing systems from the NPP Jaslovske Bohunice were studied by nondestructive Mössbauer spectroscopy. The samples were scraped from the surface and analyzed in transmission geometry. Magnetite and hematite were found to be the main components in the corrosion layers of both SGs. Dependant of the material the SG consisted of, and the location in the system where the samples were taken, the ratios between magnetite and hematite and the paramagnetic components were different. The obtained results can be used to improve corrosion safety of the VVER-440 secondary circuit as well as to optimize its water chemistry regime.

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Phase Composition Study of Corrosion Products at NPP

Cited by 2 publications

References 11 publications

Application of Mössbauer spectroscopy on corrosion products of NPP

Application of Mössbauer spectroscopy on corrosion products of NPP

Analysis of Steam Generators Corrosion Products from Slovak NPP Bohunice

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