R&D Sector for Analysis and Research of Materials

The R&D Sector for Analysis and Research of Materials carries out material science research and tests of structural materials and nuclear reactor fuel to support creation of reactors of enhanced-reliability and operational safety. The Sector also develops and implements a range of methods to identify the properties of products for their qualification as reactor core materials.

The Sector consists of:

  • Division for Metallographic Analysis of Materials Structure and Nuclear Engineering Products
  • Division for Chemical Research, Treatment of Reactor Materials, and Fuel Elements
  • Division for X-Ray Diffraction Analysis

All the divisions are equipped for operation under Radiation Safety Category 2 and take part in virtually all areas of NFC STE activities.

Division for Metallographic Analysis of Materials Structure and Nuclear Engineering Products

Optical metallography as a common method of metallographic analysis applied virtually in all material science research has existed in the Sector since its foundation. The researched products include fuel rods, absorber elements, burnable absorber rods, RCCAs, assemblies of various products, inserts, slugs, casks, gates, channels, fragments of reactor vessels, pipes, claddings, product elements after accident tests, and corium. The researched materials include nuclear fuel (metallic, ceramic, dispersion, cermet, etc.), structural materials (steels and alloys based on iron, nickel, chromium; zirconium and its alloys; refractory metals and their alloys; non-ferrous metals and their alloys), absorber materials (boron carbide, dysprosium titanate, hafnium and gadolinium-based dispersion compositions), other materials (insulating, ceramic and based on transuranium elements), welds, and overlaying welding.

The metallographic method is used to determine the inner structure of products, porosity, cracks, pipe cavities in materials, their grain structure, inclusions and various phases, and some crystal structure defects. Other activities include analysis of the surface layer structure of products and materials, microhardness measurements, and evaluation of linear dimensions of product elements in their cross-section, defect sizes, interactive layers, various structural components, and phases. Common metallographic methods have been qualified and implemented as standard ones: grain size determination in steels and alloys, determination of non-metal inclusions in steels and alloys, and α-phase concentrations in austenitic steels.

In addition to metallographic analysis combined with the quantitative processing of images (pictures) of the object structure in plane section using computer means, the method of stereometric (quantitative) metallography is also developed. Stereometric metallography allows not only to evaluate linear dimensions on a metallographic sample, but also to measure a number of product geometric parameters and structural components of materials:

  • product perimeters and cross-section areas, defects therein, and its components;
  • linear dimensions, cross-section areas, and perimeter cross-sections of structural components and phases;
  • average radii of spherical particles in the researched material and their average volumes;
  • particle volume fractions (phases) in the material and their specific surface area;
  • distribution of material particles by dimensions, evaluation of the extended phase orientation angle, etc.

The methodologies used for metallographic research into nuclear engineering materials are described in NFC STE methodology documents. The main methodologies: metallographic structure analysis, microhardness measurements, measurements of product geometry and structure of materials.

The division has modern LECO equipment:

Automatic press LECO PR-4
Grinding and polishing system
GPX-300
Metallographic microscope
Axio Observer 1M1
Hardness meter LM-700 АТ

Division for Chemical Research, Treatment of Reactor Materials, and Fuel Elements 

The main areas of the division activities include chemical analysis of fuel, absorber, and structural reactor materials for the operating and future NPP and research reactors, as well as chemical control of corrosion water environments simulating the composition of the WWER primary coolant before and after autoclave tests.
The division chemically treats reactor materials prior to using them for various tests. Specifically, chemical etching and polishing of zirconium alloys and hafnium, and electrochemical polishing of stainless steels.
Division specialists, under the NFC STE contracts and projects, have been carrying out research into methods of synthesis and analysis of the existing and future fuel, absorber, and structural reactor materials.
A new area of the division's research activities is obtaining nanosize materials used in nuclear engineering. The methodologies used for chemical analysis of nuclear engineering materials are described in NFC STE methodology documents.
The division pursues the following activities:
- sample preparation (steel, zirconium)
- preparation of the water simulating WWER-1000 primary coolant
- synthesis of nanosize dysprosium hafnate powder
- analysis of boron carbide for absorber inserts
- testing of weld joints for intergranular corrosion
The chemical analysis division has the following equipment:
- muffle furnace SNOL 1,62.51/9 - IZ
- pipe furnace SUOL 0,25.1/12 – M1
- spectrophotometer SF-16
- photocolorimeter FEK-56M
- Accuracy Class 2 scales VLR-200
- scales VLKT-500
- distiller DT-4
- pH-meter-millivoltmeter ph-150A

Division for X-Ray Diffraction Analysis

The Division for X-Ray Diffraction Analysis is equipped with an x-ray diffractometer DRON-3M.
The x-ray analysis method can be used to research:
  • phase stability and changes in the stainless steels fine texture;
  • products of interaction between structural materials and the coolant;
  • changes in the phase composition of zirconium alloys (fuel rod cladding) and other anisotropic materials;
  • changes in the structure of different oxide fuel types after operation in normal and accident modes;
  • processes of fuel and matrix interaction and transformation in dispersion compositions.
The texture analysis method allows building reverse pole figures with further determination of texture parameters of the researched material. The methodologies used for x-ray analysis of nuclear engineering materials are described in NFC STE methodology documents.
The main sector output includes developed methodologies and process instructions for analysis of fuel, absorber and structural materials, as well as reports and publications based on research results.

 

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