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

Dosimetry and analysis of the delayed gamma rays emitted from the irradiated holder device used in Mo-99 production facilities

Document Type : Research Article

Authors

Seyed Milad Miremad
Ali Bahrami-Samani
Mohsen Tabasi
Mohammad Ghannadi-Maragheh

Nuclear Science and Technology Research Institute (NSTRI), P.O. Box: 14395-836, Tehran, Iran

https://doi.org/10.22034/rpe.2024.475273.1238
Abstract
The vital radioisotope 99mTc, used in approximately 80-85% of diagnostic radiopharmaceuticals, is mostly obtained from the decay of Mo-99. To provide 100 Ci Mo-99 (6 days) per week for Iran's domestic nuclear medicine centers, an industrial plan of Mo-99 production via fission of Low Enrichment Uranium targets in the Tehran Research Reactor has recently been evaluated. In this regard and with the aim of better conceptual knowledge for the site's solid waste management, two holders made of Al-Alloy 6061 and Stainless Steel-316, which will be used to irradiate the targets, were investigated in this paper. The gamma spectrum emitted from the irradiated holder device and the corresponding dose rate were calculated by a proposed method that had been verified experimentally. When the Al-Alloy 6061 holder device was used, the calculation results indicated that the 99Mo activity produced in the mini-plates was higher and the gamma dose rate of the activated holder device decreased faster.

Highlights

  • The holder material indirectly affects the activity of Mo-99 produced in LEU targets.
  • The proposed method is reliable for the estimation of the gamma-ray spectrum.
  • The dose rate of irradiated Al-Alloy 6061 holder device decreases faster.
  • A container with 22 cm lead walls is suitable for holder batch transportations

Keywords

Dosimetry
Gamma spectroscopy
99Mo production
Tehran research reactor
Solid waste management
MCNPX
Abedi, E., Ebrahimkhani, M., Davari, A., et al. (2016). Neutronic and thermal-hydraulic analysis of fission molybdenum-99 production at Tehran Research Reactor using LEU plate targets. Applied Radiation and Isotopes, 118:160–166.
Agency, I. A. E. (2009). Regulations for the safe transport of radioactive material. International Atomic Energy Agency.
De Stefano, R., Pérot, B., Carasco, C., et al. (2020). Simulation of delayed gamma rays from neutron-induced fissions using MCNP 6.1. In EPJ Web of Conferences, volume 225, page 06007. EDP Sciences.
Domingos, D., Silva, A., Silva, J., et al. (2011). Neutronic analysis for production of fission molybdenum-99 at IEA-R1 and RMB research reactors. RRFM 2011.
Hasan, S. and Prelas, M. A. (2020). Molybdenum-99 production pathways and the sorbents for 99Mo/99nTc generator systems using (n, γ)99Mo: a review. SN Applied Sciences, 2(11):1782.
Hedayat, A., Emami, J., and Salartash, R. (2021). Determination of the neutron and gamma ray dose rates of the irradiating beam tubes of a pool-type research reactor by using Monte Carlo simulation and experimental detectors regarding radiation protection issues. International Journal of Advanced Nuclear Reactor Design and Technology, 3:27–43.
Lee, S.-K., Beyer, G. J., and Lee, J. S. (2016). Development of industrial-scale fission99Mo production process using low enriched uranium target. Nuclear Engineering and Technology, 48(3):613–623.
Lee, S.-K., Lee, S., Kang, M., et al. (2020). Development of fission99Mo production process using HANARO. Nuclear Engineering and Technology, 52(7):1517–1523.
Lou, T. P. and Ludewigt, B. (2015). MMAPDNG: A new, fast code backed by a memory-mapped database for simulating delayed γ-ray emission with MCNPX package. Computer Physics Communications, 194:10–17.
McConn, R. J., Gesh, C. J., Pagh, R. T., et al. (2011). Compendium of material composition data for radiation transport modeling. Technical report, Pacific Northwest National Lab. (PNNL), Richland, WA (United States).
McKinney, G. et al. (2007). MCNPX 2.6 x features (2006-2007). Technical report, LA-UR-07-2053. Los Alamos National Laboratory.
Muenze, R., Beyer, G. J., Ross, R., et al. (2013). The Fission-Based 99Mo Production Process ROMOL-99 and Its Application to PINSTECH Islamabad. Science and Technology of Nuclear Installations, 2013(1):932546.
Park, J. H., Choung, W., Lee, K. I., et al. (2000). Development of fission Mo-99 production technology.
Radiation Physics and Engineering
Volume 6, Issue 3
Spring 2025
Pages 1-8

  • Receive Date 26 August 2024
  • Revise Date 14 October 2024
  • Accept Date 13 December 2024

Home

Submit Manuscript

Reviewers

Contact Us