Helium and Hydrogen Embrittlement of Reactor Materials
Investigation of Helium and Hydrogen Embrittlement and Early Diagnostic Methods Development for Reactor Materials Embrittlement
Tech Area / Field
- FIR-MAT/Materials and Materials Conversion/Fission Reactors
3 Approved without Funding
Kurchatov Research Center, Russia, Moscow
- Tomsk Polytechnical University, Russia, Tomsk reg., Tomsk
- Fraunhofer Institute Zerstörungsfreie Prüfverfahren, Germany, Saarbrücken
Project summaryObject of he research project is investigation of radiation damage, He and H affects on mechanical properties and particularly on He and H embrittlement of steels used in nuclear power plants and development of early diagnostic methods for steel embrittlement on the base on acoustic aтв electromagnetic measurements. Besides, detailed investigation of ionizing radiation affect on H enhanced release from steel and on its defect structure change. Early authors of the project observed that ionizing radiation excites hydrogen subsystem in solids and results in enhanced H diffusion and release from material.
Reliable reactor material monitoring is an considerable input to reactor safety.
The project will be realized in RRC Kurchatov Institute (Moscow) and in Tomsk Polytechnic University. The equipment developed by the project participants will be used as well the standard setups and installations. The nuclear physics methods will be used to determine hydrogen and helium contents in metals: elastic recoil detection analysis (ERDA) and Rutherford back scattering (RBS). The hydrogen and defect migration during irradiation will be investigated by measurements of acoustic emission signals as well as magnetic and current vortex methods. The defects and cracks on the surfaces of the reactor’s and containers materials will be studied by optical and electronic microscopy methods. The participants have also the necessary equipment to measure the sound velocity, magnetic characteristics of materials and radiation induced hydrogen release.
Authors in course of ISTC project #2864 received important results on He-H embrittlement based on macroscopic approach to reactor material study. In particular, brittle destruction origins was shown to be bubbles crowds on grain boundaries. Criterion for brittle destruction was received.
Besides important results about H and He affect acoustic and magnetic material properties were received during the work on Istc project #2864. Effect of H mobility and release from the material increase under ionizing radiation discovered earlier by authors was investigated also. This gives a good scientific base for development of He-H embrittlement early diagnostic methods.
The investigation of hydrogen and helium role in defects formation and crystal structure reordering, and dependence of these processes on the level of radiation influence and presence of mechanical stress will allow to work out the good based prognoses of constructive material reliability.
Objects of the project are following.
- Ferrite steel H embrittlement investigations by electromagnetic methods.
- Steel damages caused by He implantation investigation by acoustic тв electromagnetic methods.
- Experimental investigation of X-ray affect on enhanced H release from materials and on defect structure change.
- Investigation of radiation defects, He and H on mechanical properties of steel.
- Theoretical calculations of electron states of H and He as well as diffusion activation energies for H and He in iron lattice.
- Comperative analysis of defects and He accumulation in materials under radiation in ion acclererators and in nuclear reactors.
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