Sucursala Cercetari Nucleare Pitesti

Objectives:

Nuclear fuel and structural materials behaviour investigation after irradiation in Cernavoda Nuclear Power Plant (NPP) or in the TRIGA 14MW research reactor at ICN Pitesti;
Manufacturing and sale of sealed nuclear radiation sources and radioisotopes used in industry, agriculture and medicine;
Radwaste characterization.

Activities:

Non-destructive Post-Irradiation Examination (PIE):

Visual inspection and photography to observe the macroscopic changes of fuel rod cladding, such as cracks, corrosion, deposits, swelling etc., occured during irradiation;
Profilometry and length measurement done both before and after irradiation to highlight the dimensional changes of the fuel rods i.e. diameter, length, diametral and axial sheath deformation, circumferential sheath ridging height, bow and ovality;
Gamma Scanning and Tomography to determine the axial and radial isotopic activity distribution inside the fuel rod, fuel column geometrical characteristics, migration of volatile fission products, flux peaking and loading homogeneity, burnup;
Eddy-current Testing to check the fuel rod cladding integrity after irradiation.

Destructive Post-Irradiation Examination:

Puncture Test to determine pressure, volume and composition of fission gas inside the fuel rod and the fuel rod inner free volume;
Optical Microscopy to highlight the fuel structural features (such as grain size, pore distribution), oxide thickness, hydriding and hardness of the sheath, fuel-sheath interface;
Mass Spectrometry on dissolution of fuel samples to determine isotopic composition and burnup;
High Performance Liquid Chromatography (HPLC) with UV-Vis detector to determine nuclear fuel burnup by the ¹³⁹La method;
Tensile Testing and Creep Testing on samples removed from fuel rod cladding and reactor pressure tube from Cernavoda NPP, in order to check their mechanical properties, such as tensile stress, fracture strength, creep rate, creep strength etc.

Sealed Nuclear Radiation Sources:

Fabrication of sealed ¹⁹²Ir and ⁶⁰Co sources for industrial radiography.

Radioactive Waste:

Radionuclidic characterization of radwaste resulting from PIE process using gamma spectrometry.

Experimental Facilities:

2 alpha-gamma heavy concrete hot cells with shielding wall thickness of 1.1 m and maximum gamma activity of 37x103 TBq. Each hot cell is provided with a crane-bridge for 20 kN and a heavy-duty manipulator for 100 daN:

Heavy concrete hot cells operating area

Transfer Cell having 2 shielding windows equipped with manipulators;
Examination Cell having 7 shielding windows equipped with manipulators.

2 alpha-gamma steel hot cells: Chemistry Cell and Metallography Cell with shielding wall thickness of 280 mm and maximum gamma activity of 37 TBq. Each hot cell has one shielding window provided with manipulators;
Steel Optical Microscope Hot Cell having shielding wall thickness of 200 mm and maximum gamma activity of 3.7 TBq;
Lead Mechanical Testing Hot Cell having shielding wall thickness of 150 (100) mm and maximum gamma activity of 3.7 TBq. This hot cell has 2 shielding windows equipped with manipulators;
Glove box;
Post-irradiation examination equipment installed in the hot cells:

Fuel rod positioning device for visual examination and photography by periscope;

Working station in heavy concrete hot cells

Profilometer, using two opposite LVDT inductive transducers. It is possible to measure the diameters of 9 to 17 mm within an accuracy of ±5 µm. The same device is used for Eddy Current Testing;
Fuel rod positioning device for gamma scanning;
Periscope equipped with a photo camera located in the hot cell shielding wall;
Collimator with variable slit for gamma-radiations located in the hot cell shielding wall;
Fuel Rod Puncture Tool for fission gas pressure and volume measurement. A gas Analyzer installed at the outside of the hot cell is used for fission gas composition analysis;
Low speed cutting machine equipped with a diamond disk for precise cutting of the fuel rod to remove samples for metallography, burnup and tensile testing;
Vacuum resin impregnation device for metallographic samples;
Mechanical grinding and polishing machines for metallographic samples;

TIG Welding Machine

Shielded optical microscope equipped with an image analyzer and a micro-hardness tester;
Tensile Testing Machine provided with a furnace with a temperature range between 20^oC to 1000^oC under air atmosphere.

Post-irradiation examination equipments installed in the radiochemistry laboratory:

Mass Spectrometer with thermal ionization;
High Performance Liquid Chromatograph (HPLC) with UV-Vis detector;
High Resolution Gamma Spectrometry Chain;
Spectrophotometer.

Sealed source manufacturing equipments installed in the hot cell:

TIG Welding Machine;
EMR - 15G gauge to measure gamma activity of the sealed sources.

Portable Gamma Spectrometry Chain for Radwaste Characterization.

Main Achievements:

Post-irradiation examination of experimental fuel rods irradiated in the 14 MW TRIGA reactor, as part of the Romanian research program for the manufacturing of CANDU fuel;
Post-irradiation examination of experimental CANDU fuel rods irradiated in the Romanian TRIGA Steady-State and Pulse Reactors under power ramp conditions, RIA (Reactivity Insertion Accident) and LOCA (Loss of Coolant Accident) conditions as part of the Romanian research program to increase the fuel safety in Cernavoda NPP operation;
Post-irradiation examination of structural materials for Cernavoda NPP reactor;
Post-irradiation examination of TRIGA LEU (Low Enriched Uranium) fuel rods to estimate their behavior and performance in operation, as part of the program for conversion of TRIGA reactor to LEU fuel;
Transport of zirconium and stainless steel alloys samples from autoclaves installed in the primary circuit of Cernavoda NPP Unit 1 reactor for corrosion monitoring;
Physical-chemical analyses, metallography and mechanical testing of materials from Cernavoda NPP to investigate defect causes;
Characterization of radioactive waste resulting from hot cells;
Rehabilitation of handling and inspection equipment installed in the hot cells;
Upgrading of post-irradiation examination infrastructure by new equipment: Tensile Testing Machine, High Performance Liquid Chromatograph, Portable Gamma Spectrometry Chain, Grinding and Polishing Machines;
Conception and achievement of a new puncture tool to measure the fission gas pressure and volume inside the fuel rod and the fuel rod inner free volume;
Concept and completion of a TIG welding machine to seal the ¹⁹²Ir and ⁶⁰Co sources;
Manufacturing and sale of sealed ¹⁹²Ir sources for industrial radiography;
Recovery of spent sealed ⁶⁰Co sources from medical therapy facilities;
Final PIEL Safety Report;
Participation in International Atomic Energy Agency (IAEA) Coordinated Research Program "Examination and Documentation Methodology for Water Reactor Fuel" (ED-WARF-II);
Participation in IAEA RER/9/076 Regional Project entitled "Strengthening Safety and Reliability of Nuclear Fuel and Materials in Nuclear Power Plants";
Participation in the European Commission Framework Program 6 HOTLAB Project entitled "European Hot Laboratories Research Capacities and Needs".