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Neutron Diffraction Study of Nuclear Reactor Materials

#3074


Neutron-Diffraction Study of Micro- and Macrostresses in Structural Ageing Alloys for Nuclear Power Engineering after Thermal and Radiation Exposure and Predicting Resistance to Radiation-Induced Swelling

Tech Area / Field

  • PHY-SSP/Solid State Physics/Physics
  • FIR-MAT/Materials/Fission Reactors
  • MAT-ALL/High Performance Metals and Alloys/Materials

Status
8 Project completed

Registration date
01.07.2004

Completion date
11.09.2007

Senior Project Manager
Novozhilov V V

Leading Institute
Ural Branch of RAS / Institute of Metal Physics, Russia, Sverdlovsk reg., Ekaterinburg

Supporting institutes

  • Joint Institute of Nuclear Research, Russia, Moscow reg., Dubna\nVNIITF, Russia, Chelyabinsk reg., Snezhinsk

Collaborators

  • Nuclear Physics Institute AS CR, Czechia, Rez\nHahn-Meitner Institut Berlin, Germany, Berlin\nNetherlands Energy Research Foundation, The Netherlands, Petten

Project summary

The Project objective is investigation of micro- and macrostresses in samples of new prospective radiation-resistant steels. Along with the traditional methods of investigating steels, the Project supposes the use of neutron stress scanners which permit, based on high-resolution neutron diffraction, to measure microstresses emerging under irradiation or solid solution decomposition (precipitation of intermetallics, carbides, radiation clusters, other precipitates) in preset volumes of samples to establish the role microstresses play in the process of Frenkel pairs recombination. Besides, neutron diffraction study of the features of precipitates formation and morphology under external uniaxial load is envisaged.

The task of the present Project will be measuring internal microstresses in the volume of samples from radiation-resistant ageing alloys in the course of formation, growth and coagulation of second-phase disperse particles. Iron-nickel alloys with precipitates of coherent intermetallides Ni3Ti (reactor steel 16Cr-15Ni-3Mo-Ti and ageing model alloy 36Ni-3Ti) and coherent carbides VC (steel 0.2C-4Cr-18Mn-1V) will be investigated. It is important to follow the dynamics of microstresses change vs. ageing (irradiation) time in the alloys with small (the first two alloys) and large (the third alloy) matrix – disperse phase lattice parameters misfit. The influence of uniaxial macrostresses (which are determined by lattice parameter change arising, in particular, in the shells of reactor fuel elements) on change in the kinetics of ageing and morphology of the precipitating disperse phases will be analyzed, which will help to predict the effect of increase or decrease of point defects recombination responsible for alloys swelling. Also, analysis of microdistortions around defect clusters formed in place of the displacement cascades under neutron irradiation, as well as comparative analysis of microstresses arising around defect clusters in the process of cascade-free electron irradiation, will be carried out. The Project also includes investigating the influence of hydrogen on change of microstresses in the vicinity of precipitate traps. As a result of the Project implementation, new fundamental data on the features of microstresses in the vicinity of different types of precipitates will be obtained, which is extremely important in predicting radiation damage in materials, and recommendations worked out on the composition and treatment of new radiation-resistant steels and alloys.

The present Project will join the efforts of participants from IMP UB RAS (Ekaterinburg), the Frank Laboratory of Neutron Physics at JINR (Dubna), and RFNC-VNIITF (Snezhinsk), who have already accumulated substantial experience in study of radiation damage in structural materials and determining internal stresses by the neutron diffraction method.

In the course of the Project implementation, foreign collaboration is envisaged, beginning from exchange of information and up to carrying out independent investigations of certified samples submitted by the Project participants.


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