ICN - Pitesti

ENSURING AND INCREASING THE PERFORMANCE OF TRIGA –ICN REACTOR


Main research areas:

  • Ensuring the reactor’s operation under nuclear safety conditions within the limits and technical conditions and in accordance with the irradiation specifications. Ensuring the reactor conversion from using of highly enriched nuclear fuel (HEU) to using low enriched fuel in the isotope 235U (LEU).

This means:

    • carrying out neutronic and thermal-hydraulic calculus using specialized codes;
    • carrying out measurements on the operating parameters, recalibrations, nondestructive tests on irradiated fuel in general and characterizing the LEU fuel behavior during irradiation;
    • ensuring the proper reactor operation.
  • Irradiation testing in specific conditions some fuel elements for establishing the fuel performance under various conditions (normal, transient);
  • Testing structural materials from Zr-Nb alloy drawn sampled from components used at Cernavoda NPP for the study of the mechanical properties and resistance at corrosion of structural materials;
  • Complementary use of neutrons to respond to some needs, ensuring an increased efficiency of the nuclear reactor use:
    • targets irradiation for the production of radioisotopes used in industry and medicine (192Ir, 131I, 99Mo);
    • neutron activation analysis to determine the concentration of some elements of interest, neutron radiography for nondestructive testing of objects including radioactive ones;
    • structural analysis using the neutron diffraction or scattering at a small angle;
    • verifications and calibrations of the equipment in reference neutron fluxes.
  • Design, manufacturing and approval of technologies and equipment for manufacturing TRIGA-LEU fuel type elements and control rods (neutron absorbent section);
  • Studies regarding the upgrading of some systems and irradiation devices from the reactor;
  • Studies regarding the possibility to increase the power of the TRIGA reactor in order to ensure a higher neutron flux density.

Main research results:

  • HEU-LEU conversion of the TRIGA Reactor:
    • The reactor operation had as main objective the irradiation of LEU fuel, simultaneously with carrying out irradiation tests using the various devices of irradiation;
    • The conversion process of the TRIGA-SSR reactor from using HEU fuel to the use of LEU fuel started in the February 1992 and continued in September 1996, March 1998, October 2000, March 2004 being completed in May 2006;
    • Periodic examination in the PIEL of a number between three and ten TRIGA LEU fuel elements to draw conclusions concerning their behavior at irradiation. The reactor performances were not affected in this process.
  • Development of TRIGA LEU fuel manufacturing technology:
    • Manufacturing concept of original low enriched uranium fuel, based on powder metallurgy for obtaining Zr-U-Er alloy, mechanical processing and controlled hydriding to obtain the ratio H / Zr = 1.6;
    • Upgrading / adaptation of used equipment for operations from the technological flux, development of command and control software, the suitable replacement of command and control systems with some modern ones based on microprocessors.
  • Neutron, mechanical design and the development of a new TRIGA control rod:
    • Development of a new concept of a control rod with 16 absorbent pins;
    • Mechanical project with absorbent elements with Incoloy cladding based on which it was performed the reactivity assessment of the new system of control rods that fully satisfies all the requirements of the "Limits and Specifications for Stationary Area of the TRIGA Reactor” provided in the operating authorization.
  • Boron and gadolinium determination through prompt gamma radiation spectrometry:
    • Design and development of the prompt gamma spectrometry facility in the radial channel of the TRIGA – ACPR reactor;
    • Development of the method for determining the concentration and isotopic abundance of the absorbent materials from the fast shutdown system from the Cernavoda  NPP reactor;
    • Development of the method for determining the elemental concentration that cannot be determined through neutron activation analysis (NAA) in environment samples.
  • Authorization of the thermal column as a standard for neutron flux measurements:
    • Design and development the device «thermal column» at the TRIGA reactor, in  order to obtain higher thermalization conditions for the neutron flux;
    • Development of the ∑∑ system in the central channel of the thermal column to generate intermediate neutrons;
    • The neutron characterization of the ∑∑ system and its instrumentation for:
      • verification and calibration of neutron measuring means (boron counters, ionization chambers boron, fission chambers, self powered detectors);
      • Performing irradiations under special conditions.
    • Drafting the documentation required for the authorization of the ∑∑ system as secondary standard for the thermal and intermediate neutron flux density.
  • Neutron activation analysis:
    • Development and implementation of the K0 standard method;
    • Analysis for the determination of the elemental composition in samples of interest for Cernavoda NPP;
    • Analysis of environmental samples;
    • Irradiation and samples characterization with contain of rhenium nanoparticles, holmium, yttrium used in treating cancerous tumors.
  • Neutronography:
    • Upgrading the neutronography facility from the TRIGA pool;
    • Carrying out neutronographies on irradiated TRIGA LEU fuel elements for the determining the performances of these elements or other components (boxes, control rods, etc.)
    • Carrying out neutronographies on irradiated fuel elements in irradiation devices from the TRIGA reactor, fuel boxes, control rods, etc.;
    • Design and development of the dry neutronography facility from the tangential channel of TRIGA ACPR reactor.
  • Neutron Diffraction:
    • Manufacturing the high resolution DIR1 neutron diffractometer, using focus with curved crystal;
    • Design and development of the SANS diffractometer;
    • The neutron diffraction method will be used in the future for:
      • actual structural analysis of some types of new materials like those with shape memory or superconductive;
      • measurements of voltages and textures, on materials;
      • studies regarding the phase transition in materials.
  • Engineering of irradiations of fuel and structural materials in the TRIGA ICN reactor:
    • Design of two systems, one hydraulic and one control command which adapted the C2Capsule irradiation device, allow the testing of a fuel element in abnormal operation conditions (in regime of type LOCA accident), under nuclear safety conditions;
    • Upgrading the C5 Capsule intended for structural materials irradiations, through building a new sample holder and a new control – command system;
    • Developing the testing capacity in the pulsed reactor (ACPR) of short duration providing the opportunity of quick examination of experimental fuel elements. Irradiation tests carried out so far in C6 Capsule in the ACPR reactor, provides  experimental data about the nuclear fuel behavior in accident regime, data which is used for the validation and calibration of computer codes, for safety analyzes development and the assessment of the risk of releasing radioactive fission products;
    • Development of ACPR tests that allow:
      • analysis of fuel elements thermo-mechanical behavior, in conditions of a rapid power transient;
      • analysis of limits and failure mechanisms of fuel element cladding;
      • establishment of the energy failure threshold depending on geometrical and micro-structural characteristics of nuclear fuel elements;
      • study of the fuel-cladding mechanical interaction;
      • development of an experimental database regarding the nuclear fuel behavior in transient regimes.
Contact: Dr. Dumitru BARBOS; e-mail: dumitru.barbos@nuclear.ro

Last modified: 06-02-2014.


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