Evaluation of neutron flux and fission rate distributions inside the JSI TRIGA Mark II reactor using multiple in-core fission chambers

Tanja Goričanec (1) , Gašper Žerovnik (1) , Loïc Barbot (2) , Damien Fourmentel (3, 2) , Christophe Destouches (4, 2) , Anže Jazbec (1) , Luka Snoj (1)

1 IJS - Jozef Stefan Institute [Ljubljana]
2 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
3 LDCAE - Laboratoire de Détection et de Caractérisation des Agents du Risque Environnemental
4 DER - Département Etude des Réacteurs

Within the bilateral project between the CEA Cadarache and the Jožef Stefan Institute (JSI) a wide variety of measurements using multiple fission chambers simultaneously inside the reactor core were performed. The fission rate axial profiles were measured at different measuring positions and at different control rod configurations. A relative comparison of calculated fission rates using the MCNP code and the measured fission rates was performed. In general the agreement between the measurements and calculations is good, with deviations within the uncertainties. For better observation and understanding of neutron flux redistributions due to the control rod movement, the neutron flux and fission rate had been tallied through the entire reactor core at different control rod configurations. The optimal detector position with minimum signal variations due to the control rod movement was determined.

Keywords: MCNP; fission chamber; TRIGA; research reactor; multiple in-core detectors; control rod movement; fission rate profile; neutron flux redistribution; neutron flux profile

Domains: Nuclear Theory [nucl-th]; Nuclear Experiment [nucl-ex]

Tanja Goričanec, Gašper Žerovnik, Loïc Barbot, Damien Fourmentel, Christophe Destouches, et al.. Evaluation of neutron flux and fission rate distributions inside the JSI TRIGA Mark II reactor using multiple in-core fission chambers. Annals of Nuclear Energy, 2018, 111, pp.407-440. ⟨10.1016/j.anucene.2017.08.017⟩. ⟨cea-02388660⟩