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  • Nuclear Power

Gap formation between steel liner and cylinder wall in reactor containment buildings

| 2026:1181 | Nils Janestad, Manouchehr Hassanzadeh, Camilo Rito Pi and Elin Torén Johansson
The reactor containment building is the most important safety barrier in a nuclear power plant. It is a cylindrical, prestressed concrete structure with an embedded steel liner on the inner face of the containment wall, designed to maintain integrity in the event of an internal accident.
Bild Gap formation between steel liner and cylinder wall in reactor containment buildings

In Sweden, holes have been drilled through the containment walls of four reactors. Following drilling, gaps were observed between the inner concrete surface and the steel liner. Such gaps may adversely affect containment performance by altering its mechanical behavior under accident loading.

This report suggests that the observed gap formation between the steel liner and the inner concrete wall is a consequence of uneven shrinkage effect together with the hole making process of drilling and releasing of prestressing force. Furthermore, the conclusion that in a defect free concrete the risk of gap formation in a concrete containment wall with a steel liner embedded is low.

Publications and reports

Here you will find reports and fact sheets from the program.

    • Report

    Testing of acoustic cameras to detect leakage through a concrete structure

    The purpose of the project was to see how well the acoustic cameras worked on a concrete containment with known leakage through the structure.

    |2026:1189Fredrik Tropp, Gabriella Wölfinger and Johanna Spåls, Ringhals AB
    2026-1189
    • Report

    Bestämning av korrosionsskyddsförmågan för olika reparationsbruk vid partiella reparationer

    This report summarizes the results of an extensive research and development project carried out within the Swedish National Road Administration BBT program and Energiforsk, Program - Nuclear Power Concrete Technology with the aim of evaluating the corrosion protection properties of different repair mortars in partial concrete repairs.

    |2026:1186Bror Sederholm, Johan Ahlström, Jan Trägårdh
    2026-1186
    • Report

    Gap formation between steel liner and cylinder wall in reactor containment buildings

    The reactor containment building is the most important safety barrier in a nuclear power plant. It is a cylindrical, prestressed concrete structure with an embedded steel liner on the inner face of the containment wall, designed to maintain integrity in the event of an internal accident.

    |2026:1181Nils Janestad, Manouchehr Hassanzadeh, Camilo Rito Pi and Elin Torén Johansson
    Bild Gap formation between steel liner and cylinder wall in reactor containment buildings
    • Report

    Methods for detection of rebar in nuclear concrete structures

    This project has reviewed non-destructive methods for detecting reinforcement in concrete structures and clarified which tasks can be performed by technically skilled in- house personnel and when specialist support is required.

    |2026:1182Magnus Nilson
    Bild Methods for detection of rebar in nuclear concrete structures