Effect of control rod insertion on the TRIGA neutron spectrum and the determination of elemental concentrations with k0-INAA
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.
Keywordsk0 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.
- 1.De Corte F (1987) The k 0-standardization method: a move to the optimization of neutron activation analysis, Habilitation Thesis. Ghent University, BelgiumGoogle Scholar
- 3.Torres MRA, Manzano JVL, Moya EV, et al. (2017) Key comparison CCQM-K127 “Contaminants and other elements in soil” Final Report, Metrologia, 54, Tech. Suppl., 08010. http://iopscience.iop.org/article/10.1088/0026-1394/54/1A/08010. Accessed 28 Aug 2017
- 6.Bučar T (2008) Evaluation of overall measurement uncertainty using the k 0-based neutron activation analysis, PhD in Slovene. Jožef Stefan International Postgraduate School, LjubljanaGoogle Scholar
- 7.Jeraj R, Ravnik M (1999) TRIGA Mark II Reactor: U(20)-Zirconium hydride fuel rods in water with graphite reflector, IEU-COMP-THERM-003. International handbook of evaluated criticality safety benchmark experiments, NEA/NSC/DOC(95)03. OECD-NEA, ParisGoogle Scholar
- 12.Štancar Ž, Snoj L, Barbot L, Lengar I, Destouches C, Lell R (2017) Reaction rate distribution experiments at the Slovenian JSI Triga Mark II research reactor, International handbook of evaluated reactor physics benchmark experiments (NEA, 7329). OECD Nucl Energy Agency, ParisGoogle Scholar
- 17.Goorley JT, et al. (2013) Initial MCNP6 Release overview—MCNP6 version 1.0. Los Alamos National Laboratory (LANL), Report number: LANL Report LA-UR-13-22934Google Scholar
- 19.Trkov A, Radulović V, Snoj L (2017) The GRUPINT neutron spectrum adjustment code—general features and characterization of the spectra in three irradiation channels of the JSI TRIGA reactor. International Symposium on Reactor Dosimetry (ISRD-16), Santa FeGoogle Scholar
- 20.k0-database 2015 (2016) The k 0-database in Excel file (k0_database_2015_12_04.xls) http://www.kayzero.com/k0naa/k0naaorg/Nuclear_Data_SC/Entries/2016/1/11_New_k0-data_Library_2015.html. Accessed 11 Jan 2016