Conceptual design of a high-performance hybrid object for applications of the fast neutron irradiation in MTRs

Document Type: Original Article


Reactor and nuclear safety school, Nuclear Science and Technology Research Institute (NSTRI), End of North Karegar Street, P.O. Box 14395-836, Tehran, Iran


‎Fast neutron irradiation is one of the most strategic radiation applications of research reactors‎. ‎Usually‎, ‎it is performed around the reactor core containing lower neutron flux‎. ‎In this paper‎, ‎a hybrid object has been introduced and analyzed to enhance irradiating applications of the fast neutrons in the core of a Material Testing Reactor (MTR)‎. ‎The tool includes an old-type low-consumed HEU control fuel element‎, ‎a dry channel‎, ‎and a Cd filter‎. ‎It is supposed to be installed at the internal neutron trap (D4 positions) of TRR core configuration‎. ‎Calculating results are very promising for using the proposed tool to increase neutron fluxes‎, ‎reduce thermal and epi-thermal neutron fluxes‎, ‎and shift the neutron spectrum toward the fast neutron region (hardening effect) at the chosen irradiating location‎. ‎Primary safety parameters are also checked and passed successfully‎. ‎Furthermore‎, ‎there are also some other presented safety items which must be checked carefully and conservatively in order to refabricate and install such a irradiating tool in an in-core location of a MTR‎.


  • Developing a high performance hybrid tool for advanced irradiating applications.
  • Fundamental concepts, design criteria and safety issues are introduced coherently.
  • The most numbers of core and safety parameters have been influenced.
  • Introducing an innovative in-core tool for spectrum shift toward fast neutrons.
  • High performance reduction of the unwanted thermal and epi-thermal neutrons.


Volume 4, Vol 4
Winter and Spring 2020
Pages 65-76
  • Receive Date: 25 November 2019
  • Revise Date: 01 February 2020
  • Accept Date: 04 March 2020