Nuclear Technology Technical Support Services

Since 2007, the General Secretariat of International Atomic Energy Agency has been encouraging the member states to establish Technical and Scientific Support Organizations for “Promoting Nuclear Safety” in accordance with the provisions of its General Convention Resolutions.

Since consulting with the nuclear licensing authority of Turkey in 2017, FİGES has contacted Germany Reactor Safety authority and identified the steps that must be taken to become a Technical Support Organization in Turkey. To become a TSO, the necessary infrastructure works and the preparations for the future steps have, since then, been initiated by FİGES.

Having adopted the “nuclear safety” as a culture, the goal of the relevant departments within the organization of FİGES, including the Department of Nuclear Technology, is to offer the necessary technical support for the safety assessment analyses during the licensing period of the nuclear reactors and other plants to be built in Turkey.

FİGES Department of Nuclear Technology (NT)

The thermal-hydraulic analyses of nuclear components, structural strength analyses, design calculations, and safety analyses are performed within the organization of FİGES. In this context, the flow characteristics of cooling cycles, strength analyses on the structural materials, seismic analyses, vibration and fatigue analyses, dispersion analyses (radioactive fallout), aircraft impact analyses, and post-accident system behavior analyses are studied by using the appropriate mathematical methods and computer assisted calculation tools.

Nuclear Safety is at the center of the activities of FİGES NT. The adopted concept of Nuclear Safety Culture is based on the principles of the applicable legislation of IAEA and Turkey.

Thermal-Hydraulic Analyses

The increased demand for the nuclear reactor safety analyses in the recent years have given rise to the rapid development of the methods focusing on the multi-dimensional thermal-hydraulic analyses. These methods have consistently become more complex to take the balance statues and the expected physical events under the temporal reactor conditions into the account. Several software and codes are available to use around the world for making advanced thermal-hydraulic calculations.

Thermal-hydraulic analyses are performed for most of the equipment constituting a nuclear reactor system. The Department of Nuclear Technology carries out these analyses for the steam generators, circulation pumps, passive cooling systems, piping systems, pressurizer, reactor core and containment by using ANSYS-CFD software.

Computational Fluid Dynamics (CFD) is the most suitable tool for the complex solutions such as Nuclear Thermal-Hydraulic Systems. However, knowledge and experience is highly required for the proper use of this tool. Creation of the mesh structure, identification of the appropriate boundary conditions, and accurate interpretation of the results is so significant.

The Department of Nuclear Technology can provide CFD calculations listed below for the Nuclear Power Plant systems:

  • Steady or transient fluid behaviors,
  • Distributions of pressure, velocity and temperature,
  • Characteristics of the heat transfers,
  • Single or multi-phase flows,
  • Radioactive fallout (dispersion) analyses,
  • Sub-channel analyses;
    • Fuel and cladding temperatures,
    • Coolant temperature,
    • Flow behavior within the assemblies,
    • Thermal-hydraulic analysis of the system components.

Safety Evaluation Analyses

The behavior of the Design Basis or Beyond Design Basis Accident conditions are mostly investigated with Nuclear Thermal-Hydraulic (TH) codes or structural analysis codes. With the help of the TH codes, safety assessment analyses can be performed in case of the severe accidents such as small or large break loss of coolant accident. Moreover, several different analyses are performed to test the safety of the reactor systems, including but not limited to the strength analyses of the structures in case of aircraft accident, structural strength calculations of the sub-systems, or strength and fatigue analyses of the equipment under seismic or dynamic conditions.

System Design and Modernization

In FİGES, nuclear reactor components can be designed, i.e. reactor vessel, steam generator, pressurizer, in accordance with the applicable standards by performing the thermal-hydraulic or structural strength analyses. With the various software and simulation tools, the design of these components can be improved for better performance.