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

Document Type : Research Article

Authors

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

Abstract

The occurrence of core uncovering following a loss of coolant accident is conceivable and should be taken into account for its significant possible consequences. Source terms are calculated using ORIGEN 2.1 code, and the gamma dose of the uncovered core is calculated for three different normal and anticipated accidents scenarios. Under containment gamma dose rates have been calculated analytically as well as using MCNPX 2.6.0 code. The uncovered core of the Tehran research reactor is supposed to operate in nominated power of 5 MW for 30 days. The results illustrated that the under-containment dose rate of gamma in some locations would be about 200 Svh-1, far from the annual occupational exposure limit of 50 mSv. For preventing this occurrence, it would be possible to use an emergency make-up tank as an engineered safety feature, with functions of the avoidance of damaging fuel after the loss of coolant accident as well as controlling exposure from the core.

Highlights

• The happening of total core uncovering is investigated in a typical research reactor.
• Validation experiment and analytical calculations are conducted further using MCNPX2.6.0 and ORIGEN 2.1 codes.
• An emergency make-up tank is designed and located to prevent from fuel damage following core uncovering.

Keywords

AEOI (2015). Logbook of Tehran Research Reactor No. 46. Technical report, Atomic Energy Organization of Iran.
AEOI (2018). Safety Analysis Report for Tehran Research Reactor. Technical report, Atomic Energy Organization of Iran.
AEOI (2020). Logbook of Tehran Research Reactor, No. 24. Technical report, Atomic Energy Organization of Iran.
Ahangari, R., Noori-Kalkhoran, O., and Sadeghi, N. (2017). Radiological dose assessment for the hypothetical severe accident of the Tehran Research Reactor and corresponding emergency response. Annals of Nuclear Energy, 99:272–278.
Anvari, A. and Safarzadeh, L. (2012). Assessment of the total effective dose equivalent for accidental release from the Tehran Research Reactor. Annals of Nuclear Energy, 50:251–255.
Bell, M. (1973). ORIGEN: the ORNL isotope generation and depletion code. Technical report, Oak Ridge National Lab., Tenn.(USA).
Boustani, E. and Khakshournia, S. (2020). An investigation for the fuel temperature of the Tehran Research Reactor during a complete loss of coolant accident. Progress in Nuclear Energy, 129:103489.
Foudil, Z., Mohamed, B., and Tahar, Z. (2017). Estimating of core inventory, source term and doses results for the NUR research reactor under a hypothetical severe accident. Progress in Nuclear Energy, 100:365–372.
IAEA (2003). IAEA-TECDOC-1344, Categorization of radioactive sources, Revision of IAEA TECDOC-1191, Categorization of radiation sources. Technical report, International Atomic Energy Agency.
IAEA (2011). Generic Procedures for Response to a Nuclear or Radiological Emergency at Research Reactors. EPR- Research reactor. Technical report, International Atomic Energy Agency.
IAEA (2012). Safety Assessment for RRs and preparation of the SAR, Specific Safety Guide No. SSG-20. Technical report, International Atomic Energy Agency.
Khan, L., Bokhari, I. H., and Raza, S. (1993). Analysis of the loss of coolant accident for LEU cores of Pakistan research reactor-1. Technical report, Pakistan Inst. of Nuclear Science and Technology.
Lamarsh, J. R., Baratta, A. J., et al. (2001). Introduction to nuclear engineering, volume 3. Prentice hall Upper Saddle River, NJ.
Manual, P. (2013). Protective Action Guides and Planning Guidance for Radiological Incidents. Draft for Interim Use and Public Comment.
Muswema, J., Ekoko, G., Lukanda, V., et al. (2015). Source term derivation and radiological safety analysis for the TRICO II research reactor in Kinshasa. Nuclear Engineering and Design, 281:51–57.
Operating-Manual (1993). Operating Manual, UMO LB 123, Berthold Technologies. Technical report, EGG Berthold.
Pelowitz, D. B. et al. (2005). MCNPXTM user’s manual. Los Alamos National Laboratory, Los Alamos.
Raza, S. S. and Iqbal, M. (2005). Atmospheric dispersion modeling for an accidental release from the Pakistan Research Reactor-1 (PARR-1). Annals of Nuclear Energy, 32(11):1157–1166.
Sadeghi, N., Sadrnia, M., and Khakshournia, S. (2013). Radiation dose calculations for an accidental release from the Tehran Research Reactor. Nuclear Engineering and Design, 257:67-71.
Ullah, S., Awan, S. E., Mirza, N. M., et al. (2010). Source term evaluation for the upgraded LEU Pakistan Research Reactor-1 under severe accidents. Nuclear Engineering and Design, 240(11):3740–3750.