Nuclear Materials, Corrosion and Surface Analysis

Thermomechanical Properties and Microstructural Analyzes

Activities

• Microstructural analysis by optical microscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry of metallic and ceramic materials;
• Teste termo-mecanice pe materiale metalice,  ceramice și compozite în intervalul de temperatură 20 ÷ 1000^oC (tracțiune, fluaj, ciclaj, mecanica ruperii);
• Explosion tests on thin-walled tubes at room temperature;
• Hydrogen and oxygen content analysis on samples of steel and alloys based on titanium and zirconium;
• Hydration of samples from nuclear structural materials;
• Uniaxial stress tests (SSRT traction and creep) in molten lead environment.

IAEA Vienna Cooperation and European Projects

• CRP 17519 – Prediction of Axial and Radial Creep in HWR Pressure Tubes;
• CRP 16705 – Benchmarking of advanced materials pre-selected for innovative nuclear reactors;
• FP7 MatISSE – GA 604862: Materials’ Innovations for a Safe and Sustainable nuclear in Europe;
• GEMMA (GEneration iv Materials Maturity), GA 755269, in the framework of EERA AISBL (JPNM – SP1 ESNII and SP2 Inovative steels);
• PATRICIA (Partitioning And Transmuter Research Initiative in a Collaborative Innovation Action), GA 945077.

Main achievements

• Expertise in failure analysis and diagnosis of degraded components from Cernavoda NPP;
• Development of experimental devices for tensile tests in molten lead;
• Tensile tests on generation IV structural materials, in molten lead medium;
• Scientific activities in international projects: MATISSE, IAEA CRP, GEMMA.

Corrosion

Activities

• Corrosion tests at high temperatures and pressures in static and dynamic regime, in operating conditions specific to the CANDU reactor;
• Investigation of the mechanisms of release, transport and deposition of corrosion products in the heat transfer circuits of the CANDU plant;
• Analysis of corroded components in nuclear installations, identification of causes and establishment of measures to reduce / prevent corrosion phenomena;
• Studies on microbiological corrosion in nuclear installations;
• Development of procedures in accordance with national and international standards for the application of new methods of analysis;
• Teste de coroziune  în mediu de plumb lichid;
• Corrosion tests in water environment at supercritical temperatures;
• Participare în proiecte internaționale, în domeniul testării la coroziune a materialelor structurale pentru reactori nucleari de GEN III și IV (proiecte H2020 – MEACTOS, ECC-SMART).

Main achievements

• Dynamic on-load cracking corrosion testing of samples from Inconel 182 and 316L steel at high temperatures and pressures (2880C, 90bar, 2ppm O dissolved) with different traction speeds within the MEACTOS H2020 project;
• Identification of the main types of degradations specific to the steam generator piping;
• Identification of the causes and conditions of cracking corrosion under load on the steam generator piping;
• Determination of the thickness layer of oxides and protective coatings on metal samples (beneficiary S.C.METIGLA SRL)
• Corrosion rating of welded samples from duplex steels, according to ASTM G-48 (beneficiary SC DAMEN)
• Recommendations for minimizing the effects of microbiological corrosion in raw water-cooled systems from Cernavoda NPP;
• Identification of the corrosion behavior in liquid Pb medium, of 15Cr15Ti and 316L steels.

LADICON - CNCAN notified laboratory

The Laboratory for Analysis and Diagnosis of Corroded Metal Components in Nuclear Installations (LADICON) is part of the Nuclear Materials and Corrosion section and has as main objectives:

• analysis of degraded metal components using specific tests and characterization methods to identify the causes
• identification of technical solutions to reduce / prevent the degradation phenomena,
• evaluation of the corrosion behavior of metallic materials in different environments.

The quality assurance of the tests within LADICON is performed in accordance with the requirements of the SR EN ISO / CEI 17025 standard, with the requirements of the clients and of the regulatory authorities in the field (CNCAN Bucharest). The laboratory is notified as a testing laboratory by CNCAN Notification no. LI-04_LADICON / 2020.

Test / analysis methods

• Determination of susceptibility to generalized and localized corrosion by gravimetric analysis and accelerated chemical tests;
• Analysis by metallographic microscopy of metal components (measurement of oxide layer thickness / organic deposits / ceramic deposits, determination of average grain size, determination of non-metallic inclusions)
• Determination of corrosion susceptibility of structural materials by electrochemical methods (variation of corrosion potential, linear polarization and cyclic polarization);
• Identification of phase composition by X-ray diffraction (qualitative and quantitative analysis on polycrystalline materials, investigation of thin layers, determination of crystallite size and microtensions, quantitative analysis of internal stresses, X-ray diffraction at radiant incidence, microdiffraction)..

Main achievements

• Identification by X-ray diffraction analysis of the chemical composition and crystalline state of the corrosion products on the Milipore filters (beneficiary Cernavoda NPP)
• Fault analysis of the rocker cover from a diesel engine from Unit 1 Cernavoda NPP  
• Development of accelerated chemical methods: Determination of the minimum critical corrosion initiation temperature in the crevice for stainless steels; Determination of susceptibility to intergranular corrosion of welded joints 
• Teste electrochimice de determinare a vitezelor de coroziune a materialelor metalice (beneficiar CNE  Cernavodă)
• Analyzes by metallographic microscopy (beneficiaries Unit 1 Cernavoda NPP; SC METIGLA SRL)
• Accelerated chemical tests to identify pitting corrosion (beneficiary Societatea Șantierul Naval DAMEN SA, Galați)

Nuclear fuels

Activities

• Production of iridium disks, which will be used as irradiation targets in the TRIGA reactor and subsequently as closed radioactive sources of Ir192, used for industrial radiography.
• Experimental research activities on the aging of concrete cladding structures.
• Evaluation of the oxidation behavior of uranium dioxide fuel in severe accident conditions.
• Experimental studies for the development of nitride fuels by the hydration-nitriding method.
• Fuel-coolant interaction tests for LFR reactors.
• Production of mixed thorium and uranium oxide powder by chemical method.
• Production of mixed thorium and uranium oxide tablets.
• Fabricarea de pastile  de UO₂ cu grad de îmbogățire de 1÷10% ²³⁵U.
• Fabricarea baghetelor combustibile pe bază de uraniu slab îmbogățit prin metoda  metalurgiei pulberilor.
• Recuperarea uraniului sub formă de UO₂ din produsele secundare rezultate la fabricația baghetelor combustibile.
• Construction of an installation for welding the ECE-LEU experimental fuel element.
• Determination of optimal welding parameters by structural analysis and determination of mechanical properties.
• Design and construction of an ECE-LEU vacuum chamber.
• Studies and experimental research on the storage of hydrogen isotopes in the form of metal hydride.

• Research on improving tritium management knowledge in the field of nuclear fission.
• Participation in international projects in the field of tritium management in the field of nuclear fission and fusion (project H2020-TRANSAT).

Main achievements

• Production of instrumented experimental fuel elements for irradiation in the TRIGA ICN reactor.
• Production of iridium disks.
• Obtaining U-Zr alloys with different content from Zr.

Analiza supreafețelor

Activities

• Surface treatment by electrolytic oxidation in plasma (PEO)
• Analiza suprafeței prin spectroscopie de fotoelectroni cu raze X (Engl. XPS)
• Characterization of corrosion resistance

Certifications

• The laboratory is designated as a Notified Test Laboratory, according to the Notification LI 1_ESCALAB / 2020 issued by the National Commission for the Nuclear Activities Control (CNCAN).

Main achievements

• Methods of obtaining ceramic coatings of mixed metal oxides resistant to corrosion and wear on Zr-2,5Nb and Titan alloys in order to increase their service life, presented in the last 5 years, in:
  • 33 research papers,
  • 17 scientific articles indexed by ISI,
  • 6 scientific articles indexed in international databases,
  • 7 scientific papers presented at conferences (national and international).

• Training students in their final years in the field of obtaining ceramic coatings by the technique of plasma electrolytic oxidation (PEO) and their characterization by the technique of X-ray electron spectroscopy (XPS) by supporting, in the last 5 years,:
  • 6 bachelor's / dissertation papers.

 

Contact person CS III Dorel Benga, e-mail: dorel.benga@nuclear.ro