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Materials Testing on Radioactive Materials ("Hot Cell")

The safe operation of nuclear power plants and nuclear repositories is a key research topic all over the world. In order to ensure a high degree of safety, the materials used and real-world conditions, in this case with radioactivity, must be tested. ZwickRoell has supplied a tensile tester and a pendulum impact tester for an international research project.

Nuclear power stations in Europe are generally designed to operate for approx. 40 years. Despite the change in energy policy and Germany's corresponding phase-out decision, nuclear power plants will still be required to operate for longer periods (60 to 80 years) worldwide. Longer operating periods and the associated aging effects on reactor materials must not jeopardize safety. ZwickRoell has supplied an automated pendulum impact tester and a tensile testing machine to Isotope Technologies Dresden (ITD) for an international research project. ITD delivers "hot cells" including testing machines to the Kharkow Institute of Physics and Technologies (Ukraine) where the tests are performed. The research project is being subsidized by the US Department of Energy and the Oak Ridge National Laboratory, which is part of the department.

Due to longer operation periods of nuclear reactors, materials are subject to a higher neutron dose from a temporal perspective. How are the materials influenced by this? Are the procedures and prediction models used to observe brittleness suitable for the long-term operation of nuclear power stations or must they be adjusted? To better answer these questions and others, Charpy impact tests and tensile tests are performed to determine stiffness and tensile strength of the materials.

Charpy impact tests

ITD supplies what are known as "hot cells" for an international research project in which different tests on radioactive materials are performed. Charpy impact tests are performed on a ZwickRoell RKP 450 pendulum impact tester. The pendulum is raised automatically and is equipped with a steplessly adjustable release height. It has special paint, remote electronics and various other features for use with hot cells. Before the actual test, specimen can be thermoregulated between -180 °C and +600 °C. The automatic insertion and centering the specimen means tests display a high degree of repeatability.

Tensile tests

An AllroundLine (Fmax 30 kN) testing machine is used for tensile tests that has also been adapted to operate in a radioactive environment. For example, it is painted with a special paint and features radiation-resistant cable insulation. A laserXtens with lead housing is used for measuring specimen deformation. This allows non-contact measurements up to 350 °C within a temperature control chamber. The complete system is designed for operating with a manipulator. Smaller radioactive samples can also be safely inserted and removed after the test.