Radiation & Reactor Theory
 
The Radiation and Reactor Theory (RRT) Group falls within the Pelindaba Nuclear Institute leg of Necsa.
The main focus of RRT is to research, develop and apply advanced calculation methods in the fields of radiation transport and reactor physics.

RRT has been involved in many theoretical reactor physics analyses the past twenty years. These analyses cover different types of calculations, namely neutron reactor core calculations, criticality analyses as well as source term and radiation shielding calculations. An important aspect of the groups' activities is the research, development and use of the locally developed reactor core analyses system OSCAR-3. Since 1995 OSCAR-3 has been used extensively for reload and utilisation support calculations for the SAFARI reactor (MTR). Other research reactor operators and research groups also use the code internationally.

The last three years the group has also got involved in the South African based Pebble Bed Modular Reactor concept and is involved in the day-to-day core neutron design and supporting analyses.
 
Research & development

  • Maintain and expand a reactor physics competence in South Africa.
  • This competence is evidenced in the locally developed OSCAR-3 calculation system (applicable to MTRs and PWRs) and international publications.
  • The first version of OSCAR-3 together with other internationally recognised code systems (SCALE, MCNP etc) are used in support of the local nuclear industry.
  • Participation in international research projects is also conducted from time to time.

Click here to visit the RRT official website.

OSCAR-3

OSCAR-3 is an advanced neutron code system developed and maintained by the RRT group.

  • Methods research and development
  • Code and module development
  • Core analysis, reload and safety calculations
  • Users:
    • SAFARI-1 at Necsa in South Africa
  • Customised for research reactors but also used for PWR reload analysis

SAFARI-1 support

"SAFARI-1 is one of the few research reactors that has a dedicated team of reactor physicists who develop their own customised reactor physics tools in support of the reactor utilisation."

This support enables SAFARI-1 to operate more economically and enhances the commercial exploitation of the irradiation facilities.

The calculation support provided by the RRT team forms a vital part of the safe, reliable and economical operation of SAFARI-1.

  • Safety analysis
  • Fuel reload optimisation and reload design
  • Irradiation rig design ensuring optimum neutron flux and neutron energy spectrum
  • Optimisation and maximisation of current and new isotope production
  • Low Enriched Fuel (LEU) studies and participation in the international RERTR (Reduced Enrichment for Research and Test Reactors) program
  • Examples:

          - The rig design for the Mo-99 target plates Mo-99 generators used for Medical applications
          - Design of rig for NTD silicon used in computers
          - Re-licensing of SAFARI and the redefinition of operating margins.
          - Beam characterisation and calculation support.
 
To supply this support the OSCAR-3 system plays a vital role. MCNP models are also employed for specific problems when required.

PBMR support

RRT forms an essential part of the PBMR design team and members of the team work at the PBMR offices on:

  • Reactor core neutron design
  • Core safety analysis
  • Neutron and gamma shield design
  • Fission product and activation source term calculations
  • Verification and validation of methods and codes
  • Defining and developing the next generation of core analysis tools for the PBMR reactor
  • Examples
  • Design and calculations for the used and spent fuel tanks
  • Benchmarking with the ASTRA critical facility at the Kurchatov Institute, Russia

Consulting services

Expert calculation and analyses services are provided.

  • Reactor physics analysis
  • Shielding design
  • Criticality evaluations
  • Cross section library generation
  • Nuclide inventory and source term calculations

Our responsibility

RRT is serious about training and sharing our knowledge as well as:

  • Assisting with reactor physics courses at UNW and WITS
  • Present the MSc in Reactor Science at PU for CHE
  • IAEA expert missions into Africa
  • AFRA IV-11 - Operation, safety and utilisation of research reactors in Africa (RRT involved for 5 years)
  • In-house training
  • Papers and publications

Tools

  • OSCAR-3 - Locally developed system to perform MTR and PWR core analyses
  • SCALE - general system of codes used to perform criticality, neutronic, source term and shielding analyses
  • MCNP - Monte Carlo code performing neutron, gamma and beta transport calculations
  • NJOY - cross section processing package to extract data from basic libraries
  • FISPACT - neutron activation analysis
Copyright Necsa 2011