At Research Centre Řež (Centrum výzkumu Řež s.r.o., CVŘ) in the department of Material Analysis (before Material and Mechanical Properties), where analysis of materials was commonly performed by microscopy techniques, was added a powder X-ray diffraction (XRD) facility for analysis preferentially of irradiated materials, as a complement to the existent analytical techniques. Annexed to the XRD facility is the preparation room of irradiated geological samples, building materials and ceramics located in the hot-cells facility building [1].
The milling and preparation of specimen for XRD analysis of irradiated, or radioactive, materials is carried out inside of a shielded glove box, which is kept at negative pressure to avoid leakage of radioactive powder outside the glove box, afterwards the samples are transferred to the XRD laboratory in a sealed container to be analysed in a diffractometer Empyrean (Malvern-PANalytical) with a Co-anode X-ray tube, with the option of automatic loading of samples, and remote operation [2].
Currently at CVŘ XRD lab several research topics connected to nuclear energy are being investigated, they can be divided in two groups:
1) influence of the neutron irradiation on concrete aggregates [3] used as biological shield in nuclear reactors. Concrete aggregates (e.g. quartz, feldspars) under irradiation experience a radiation-induced volumetric expansion, which can cause cracking of the concrete thus reducing its lifetime. Using XRD we can monitor the changes in lattice parameters and unit cell volume of the mineral aggregates after irradiation at different neutron fluences.
2) monitoring of stability of materials used as fixation matrices for radioactive waste in a simulated environment of a deep geological repository. The materials used as fixation matrices vary from cement, clays [4], geopolymer, mixture of clay and cement. Those matrices are storage under synthetic water, simulating the underground water that could fill the geological repository, afterwards changes in the mineral composition are monitored on the surface and inside the matrices using XRD.
This work has been realized thanks to the support of the Technology Agency of the Czech Republic, program TREND in the project FW01010115.