A peer-reviewed journal published by K. N. Toosi University of Technology

Document Type : Research Article

Author

Reactor and Nuclear Safety Research School, Nuclear Science and Technology Research Institute (NSTRI), Tehran, Iran

Abstract

Simulation work provides valuable information on the behavior of different research reactor neutron analysis facilities. The present study considered neutron and secondary-gamma dose rate variations by applying a sapphire crystal inside the D channel in Tehran Research Reactor (TRR). The MCNPX computational code was used to model the channel and its designed shield. Neutron and gamma dose rates distributions were calculated with a sapphire crystal modeling to investigate the neutron diffraction facility hall dose rates. The data from the dose rate simulations were compared with the experimental data available at a power of 4.2 MW from the research reactor. The comparison showed that there is very good conformity between two data series. The simulated neutron dose rate in front of the main shield overestimated the measurement data by 57% in closed-shutter situation and underestimated the measured data by 32% in open-shutter measurement situation. The investigation has shown that adjusting the crystal size to the channel size is considerably effective, especially at high leakage positions.

Highlights

  • Sapphire crystal has noticeable impact on the dose rates around a neutron beam line shield.
  • Simulation methods are vital to investigate the dose rates behavior without practical high costs.
  • Benchmark studies are very important procedures to evaluate the simulation accuracy degree.

Keywords

Adib, M. (2005). Cross-section of single-crystal materials used as thermal neutron filters.
Adib, M. (2008). Attenuation of Reactor Gamma Radiation and Fast Neutrons Through Large Single-Crystal Materials. Proceedings of the 3rdEnvironmental Physics Conference, 19-23 Feb. 2008, Aswan, Egypt, pp.257-272.
Adib, M. and Kilany, M. (2003). On the use of bismuth as a neutron filter. Radiation Physics and Chemistry, 66(2):81–88.
Adib, M., Kilany, M., Habib, N., et al. (2003). Neutron Transmission of Single-Crystal Sapphire Filters. 4thConference on Nuclear and Particle Physic; EG0600145 ,11-15 Oct. 2003, Fayouni , Egypt, pp.224-237.
Adib, M., Kilany, M., Habib, N., et al. (2005). Neutron trans- mission of single-crystal sapphire filters. Czechoslovak Journal of Physics, 55(5):563–578.
Born, R., Hohlwein, D., Schneider, J., et al. (1987). Characterization of a sapphire single crystal for the use as filter in thermal neutron scattering. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 262(2-3):359–365.
Mach, W. (2018). Installation of a neutron beam instrument at the TRIGA reactor in Vienna. PhD thesis, Wien.
Menarebazari, Z. A., Jafari, H., Gholamzadeh, Z., et al. (2022). The design and optimization of a radiation shield for the Tehran Research Reactor’s neutron diffraction facility. Progress in Nuclear Energy, 148:104224.
Mirvakili, S., Keyvani, M., Arshi, S. S., et al. (2012). Possibility evaluation of eliminating the saturated control fuel element from Tehran research reactor core. Nuclear Engineering and Design, 248:197–205.
Mishra, K. K., Hawari, A. I., and Gillette, V. H. (2006). Design and performance of a thermal neutron imaging facility at the North Carolina State University PULSTAR reactor. IEEE Transactions on Nuclear Science, 53(6):3904–3911.
Nieman, H., Tennant, D., and Dolling, G. (1980). Single crystal filters for neutron spectrometry. Review of Scientific Instruments, 51(10):1299–1303.
Pelowitz, D. B. et al. (2005). MCNPX users manual. Los Alamos National Laboratory, Los Alamos, 5:369.
Stamatelatos, I. and Messoloras, S. (2000). Sapphire filter thickness optimization in neutron scattering instruments. Review of Scientific Instruments, 71(1):70–73.
Zahar, N., Benchekroun, D., Belhorma, B., et al. (2016). Study of Sapphire and MgO as Thermal Neutron Filters for The TRIGA Moroccan Reactor Beam ports. International Journal of Advanced Research, 4(7):560–567.