Reduction of Plutonium Production in Heavy Water Research Reactor: A Feasibility Study through Neutronic Analysis Using MCNPX2.6 and CINDER90 Codes

Authors: H. Shamoradifar, B. Teimuri, P. Parvaresh, S. Mohammadi

Abstract:

One of the main characteristics of Heavy Water Moderated Reactors is their high production of plutonium. This article demonstrates the possibility of reduction of plutonium and other actinides in Heavy Water Research Reactor. Among the many ways for reducing plutonium production in a heavy water reactor, in this research, changing the fuel from natural Uranium fuel to Thorium-Uranium mixed fuel was focused. The main fissile nucleus in Thorium-Uranium fuels is U-233 which would be produced after neutron absorption by Th-232, so the Thorium-Uranium fuels have some known advantages compared to the Uranium fuels. Due to this fact, four Thorium-Uranium fuels with different compositions ratios were chosen in our simulations; a) 10% UO₂-90% THO₂ (enriched= 20%); b) 15% UO₂-85% THO₂ (enriched= 10%); c) 30% UO₂-70% THO₂ (enriched= 5%); d) 35% UO₂-65% THO₂ (enriched= 3.7%). The natural Uranium Oxide (UO₂) is considered as the reference fuel, in other words all of the calculated data are compared with the related data from Uranium fuel. Neutronic parameters were calculated and used as the comparison parameters. All calculations were performed by Monte Carol (MCNPX2.6) steady state reaction rate calculation linked to a deterministic depletion calculation (CINDER90). The obtained computational data showed that Thorium-Uranium fuels with four different fissile compositions ratios can satisfy the safety and operating requirements for Heavy Water Research Reactor. Furthermore, Thorium-Uranium fuels have a very good proliferation resistance and consume less fissile material than uranium fuels at the same reactor operation time. Using mixed Thorium-Uranium fuels reduced the long-lived α emitter, high radiotoxic wastes and the radio toxicity level of spent fuel.

Keywords: Burn-up, heavy water reactor, minor actinides, Monte Carlo, proliferation resistance.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1129534

References:

[1] Thorium. (2006). Retrieved August 31, 2006 from http://www.world-nuclear.org/info/inf62.htm
[2] M.S. Kazimi, “Thorium fuel for nuclear energy,” American Scientist, 91(5), 408, Retrieved August 1, 2006.
[3] M.S. Kazimi, R.K. Czerwinski, M.J. Driscoll, P. Hejzlar, J.E. Meyer, “On the use of thorium in light water reactors,” (Academic Report no. MIT-NFC-TR-016). Cambridge, Massachusetts: Massachusetts Institute of Technology, August 1, 2006.
[4] A. Ahmad, F.V. Hippel and A. Glaser, “Conversion Options for Iran’s IR-40 Reactor with Reduced Plutonium Production,” Program on Science and Global Security, Princeton University, 2014.
[5] G. W. McKinney, J. W. Durkee, J. S. Elson, M. L. Fensin, J. S. Hendricks, M. R. James, R. C. Johns, D. B. Pelowitz, L S Waters T A Wilcox L. S. Waters, T. A. Wilcox, “MCNPX 2. 7 0 – New Features Demonstrated,” Nuclear Engineering and Nonproliferation Division, LANL IEEE NSS/MIC Anaheim, CA, October 29 - November 3, 2012.
[6] J. S. Hendricks, G.W. McKinney, M.L. Fensin, M. R. James, R.C. Johns, J. W. Durkee, J. P. Finch, D. B. Pelowitz, L. S. Waters, M. W. Johnson, “MCNPX 2.6.0 Extensions,” Los Alamos National Laboratory, LA-UR-08-2216, APRIL 11, 2008.
[7] R.S. Kemp, “Two Methods for Converting Iran's IR-40 Reactor to Use Low-Enriched-Uranium Fuel to Improve Proliferation Resistance after Startup,” Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, March 2014.
[8] N. Prasad, A. Kumar, U. Kannan, A. Kumar, P.D. Krishnani and R.K. Sinha, “Study for use of LEU along with Thorium in Advanced Heavy Water Reactor (AHWR) to Enhance Proliferation Resistance Characteristics of Fuel,” Bhabha Atomic Research Centre2015.