Effect of control rod insertion on the TRIGA neutron spectrum and the determination of elemental concentrations with k0-INAA

  • Lojze Gačnik
  • Klemen Ambrožič
  • Sebastjan Rupnik
  • Vladimir Radulović
  • Radojko Jaćimović


We suspected that changes in the neutron spectrum, caused by varying control rod positions in routine steady state operation of our TRIGA nuclear reactor, coupled with the k0 formalism, were the cause of systematically biased concentrations compared to assigned values. To confirm this, we investigated the effect of control rod insertion on the spectrum parameters f and α, and the subsequent effect on the determination of concentrations with k0-INAA. We determined the spectra for three control rod configurations, in three irradiation positions, using the bare triple-monitor method, as well as using MCNP simulations, and compared the results.


k0 instrumental neutron activation analysis Neutron spectrum determination Neutron spectrum variability 



The work was performed in the scope of program group P1-0143 at the Jožef Stefan Institute, within the project PR-06174, financed by the Slovenian Research Agency (ARRS). The authors wish to thank the Metrology Institute of the Republic of Slovenia (MIRS), as their work contributes to MIRS/IJS Contract No. 6401-5/2009/27 for activities and obligations performed as a Designate Institute as an etalon for amount of substance/chemical trace elements/in the organic and inorganic materials. The work of this study is part of project ENVCRM, which was funded within the framework of the EMPIR.


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Copyright information

© Akadémiai Kiadó, Budapest, Hungary 2018

Authors and Affiliations

  1. 1.Department of Environmental SciencesJožef Stefan InstituteLjubljanaSlovenia
  2. 2.Reactor Physics DepartmentJožef Stefan InstituteLjubljanaSlovenia
  3. 3.Reactor Infrastructure CentreJožef Stefan InstituteLjubljanaSlovenia
  4. 4.Jozef Stefan International Postgraduate SchoolLjubljanaSlovenia

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