Community Research and Development Information Service - CORDIS

Reactor containments

The main elements of reinforced concrete and prestressed concrete structures of reator buildings were investigated concerning their long term performance, a period of about 100 years after decommissioning. As reference plants 2 German nuclear power plants were chosen, one pressurized water reactor (PWR) type and one boiling water reactor BWR type.

A survey of the general long term behaviour of the structural elements, and especially of their components, concrete and reinforcement steel, was made. The development of strength and the influence of carbonation on the concrete were evaluated. As far as the reinforcement is concerned, the corrosion mechanism is important.

The monitoring procedures that are proposed, depend on the importance and on the range of utilization of the materials under dead load. No severe effect on the stability of the concrete structures of the plants was expected if the durability of anchorage elements or bearings would not last for the regarded time after decommissioning. It is recommended for all inner structural elements and especially those which are located in nonaccessible areas to maintain unchanged carbonation retarding and corrosion retarding climatic conditions. The stability of the reference plants is expected to endure at least 100 years after decommissioning.

It is essential to guarantee leak tightness of the steel containment or steel liner and to assure integrity of important structures up to ultimate demolition of the plant. For the 100 year period in question after decommissioning, the type and extent of corrosion damage are discussed for areas classified as potential risk areas and measures to assure enclosure are recommended with monitoring and conservation measures.

Long term examinations of silicon sealing materials used in safety related areas were performed. On the basis of the test results and additional literature studies an attempt was made to evaluate the long term suitability of this silicon material as sealing material.

Nondestructive tests using the ultrasonic test technique were performed on a component and on calibration blocks in order to detect corrosion in nonaccessible areas. On the basis of these test results it was possible to confirm corrosion in these areas.

Reported by

Stangenberg und Partner Ingenieur GmbH
Viktoristrasse 47
44787 Bochum
Germany
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