Radiation Physics and Engineering
A peer-reviewed journal published by K. N. Toosi University of Technology

Investigating the emitted dose from small and large out-of-tank irradiation channels of a low power research reactor through calculation and measurement

Document Type : Research Article

Authors

Javad Mokhtari 1
Maryam Hassanvand 2
Mohammad Hossein Choopan Dastjerdi 1
Elham Maleki 2

1 Reactor and Nuclear Safety Research School, Nuclear Science and Technology Research Institute, AEOI, Tehran, Iran

2 Department of Physics, Isfahan University of Technology, Isfahan, Iran

https://doi.org/10.22034/rpe.2025.545970.1300
Abstract
Two external neutron beamlines of small and large sizes have been installed in the Isfahan Miniature Neutron Source Reactor (MNSR) pool in recent years to perform neutron radiography as well as irradiation experiments for large samples out of biological shield of reactor. These channels are located outside the reactor tank and exit vertically tangentially from the biological shield of the reactor, which is the pool water. These channels, that were not included in the initial design of MNSR, actually generate neutron beam lines in the reactor hall, about 6 meters away from the reactor core. In this study, the delivered neutron and gamma dose rates at the outlet of these channels at the maximum power of reactor, i.e. 30 kW, has been determined through simulation and experiments. Results shows that the calculated and measured gamma dose rates at the outlet of the large size channel are 45.81 ± 3% and 47.32 ± 6% mSv.h-1, respectively and the calculated and measured neutron dose rates are 11.72 ± 5% and 11.31 ± 3% mSv.h-1, respectively. In the case of small size channel, the calculated and measured gamma dose rates at the outlet of this channel are 10.53 ± 4% and 10.22 ± 6% mSv.h-1, respectively and the calculated and measured neutron dose rates are 2.22 ± 5% and 2.11 ± 8% mSv.h-1, respectively. Also, the neutron and gamma dose rate distribution in the reactor hall for different modes of operation of these two channels were qualitatively determined.

Highlights

  • Using the verified model of calculation, maps of neutron and gamma dose rates within the reactor hall were obtained.
  • Simulations and measurements were performed to determine the neutron and gamma dose rates in the Isfahan MNSR.
  • The neutron and gamma dose rate distribution in the reactor hall of these two channels were qualitatively determined.

Keywords

Neutron dose rate
Gamma dose rate
MNSR
Neutron beamline
Dosimetry
MCNP simulation

Copyright
RPE is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).

Conflict of Interest
The authors declare no potential conflict of interest regarding the publication of this work‎.

Funding
‎The authors declare that no funds‎, ‎grants‎, ‎or other financial support were received during the preparation of this manuscript‎.

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Radiation Physics and Engineering
Volume 7, Issue 1
Winter 2026
Pages 19-25

  • Receive Date 08 September 2025
  • Revise Date 27 October 2025
  • Accept Date 16 November 2025

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