Title:                   Witness concrete samples

Full title:            Long-term monitoring of load-bearing structural concrete around the reactor shaft of the Dukovany NPP

Client:                ČEZ, a.s.

                           Dukovany Nuclear Power Plant

Purpose:           Controlled aging and reliability of concrete structures

Investigator:     Petr Štěpánek et al.

According to the “Methodology of testing concrete samples intended for long-term monitoring of the properties of load-bearing structural concrete around the reactor at Units 1 and 3 of the Dukovany NPP” designed by the team of Prof. Štěpánek and created in 2005, unique measurements of so-called witness concrete samples will be carried out from 2028.

On concrete samples taken from various parts of the power plant and on other samples produced later, their degradation is ensured so that it is possible to predict the load-bearing capacity of the concrete over time. The aim is also to create constitutive relations for concrete exposed to a combination of temperature, humidity and radiation loads, which are/will be used to estimate the reliability of the power plant’s load-bearing structures over time.

The effects of radiation, temperature and humidity on individual components of concrete, such as aggregate and cement mortar, and subsequently the effect of radiation on the concrete as a whole were determined on witness samples. Radiation exposures were then determined from a series of comparative tests and from the literature; above these limits, significant radiation damage is achieved. Of course, significant physical and mechanical properties of concrete and their change over time are also monitored.