Analyses and improvement of fuel temperature coefficient of rock-like oxide fuel in LWRs from neutronic aspect

  • Shelley, Afroza (American International University-Bangladesh, Department of Physics)
  • Received : 2019.08.26
  • Accepted : 2019.12.02
  • Published : 2020.06.25


Fuel temperature coefficient (FTC) of PuO2+ZrO2 (ROX) fueled LWR cell is analyzed neutronically with reactor- and weapons-grade plutonium fuels in comparison with a U-free PuO2+ThO2 (TOX), and a conventional MOX fuel cells. The FTC value of a ROX fueled LWR is smaller compared to a TOX or a MOX fueled LWRs and becomes extremely positive especially, at EOL. This is because when fuel temperature is increased, thermal neutron spectrum is shifted to harder, which is extreme at EOL in ROX fuel than that in TOX and MOX fuels. Consequently at EOL, 239Pu and 241Pu contributes to positive fuel temperature reactivity (FTR) in ROX fuel, while they have negative contribution in TOX and MOX fuels. The FTC problem of ROX fuel is mitigated by additive ThO2, UO2 or Er2O3. In ROX-additive fuel, the atomic density of fissile Pu becomes more than additive free ROX fuel especially at EOL, which is the main cause to improve the FTC problem. The density of fissile Pu is more effective to decrease the thermal spectrum shifts with increase the fuel temperature than additive ThO2, UO2 or Er2O3 in ROX fuel.


  1. H. Akie, T. Muromura, H. Takano, S. Matsuura, A new fuel material for once-through plutonium burning, Nucl. Technol. 107 (1994) 182.
  2. M. Delpech, A. Puill, Plutonium free uranium fuel in PWR concepts: neutronic aspects, in: International Conference on Future Nuclear Systems (GLOBAL'97), Yokohama, Japan Oct. 5-10, 1997.
  3. P. Chodak III, J.J. Buksa, A practical strategy for reducing the future security risk of United States spent nuclear fuel, in: International Conference on Future Nuclear Systems (GLOBAL'97), Yokohama, Japan Oct. 5-10, 1997.
  4. C. Lombardi, A. Mazzola, E. Padovani, M.E. Ricotti, Neutronic analysis of U-free inert matrix and thoria fuels for plutonium disposition in pressurized water reactors, J. Nucl. Mater. 274 (1999) 181.
  5. J.L. Kloosterman, P.M.G. Damen, Reactor physics aspects of plutonium burning in inert matrix fuel, J. Nucl. Mater. 274 (1999) 112.
  6. H. Takano, H. Akie, T. Mutomura, Annihilation of excess plutonium by rock-like fuel in light-water reactors, in: Proc. 6th Int. Conf. Nuclear Engineering (Icone-6), May 10-14, 1998, San Diego, USA, ICONE, 1998, p. 6065.
  7. A. Shelley, H. Akie, H. Takano, H. Sekimoto, Parametric studies on plutonium transmutation using uranium-free fuels in light water reactors, Nucl. Technol. 131 (2000) 197-209.
  8. A. Shelley, H. Akie, H. Takano, H. Sekimoto, Radiotoxicity hazard of U-free $PuO_2+ZrO_2$ and $PuO_2+ThO_2$ spent fuels of LWRs, Prog. Nucl. Energy 37 (2000) 377-382.
  9. H. Akie, H. Takano, Y. Anoda, Core design study on rock-like oxide fuel light water reactor and improvements of core characteristics, J. Nucl. Mater. 274 (1999) 139.
  10. J.M. Paratte, R. Chawala, On the physics feasibility of LWR plutonium fuels without uranium, Ann. Nucl. Energy 22 (1995) 471.
  11. G. Ledergerber, et al., Using civilian plutonium in LWRs with an inert matrix fuel (IMF), in: International Conference on Future Nuclear Systems (GLOBAL'97), Yokohama, Japan Oct. 5-10, 1997.
  12. F. Vettraino, C. Lombardi, A. Mazzola, Inert matrix fuels for Pu disposition in PWRs, in: 6th Int. Conf. Nuclear Engineering (Icone-6), San Diego, USA, May 10-14, 1998.
  13. A. Shelley, H. Akie, H. Takano, H. Sekimoto, Comparison of the burnup characteristics and radiotoxicity hazards of rock-like oxide fuel with different types of additives, J. Nucl. Sci. Technol. 38 (2001) 134-142.
  14. N.J. Nicholas, K.L. Coop, R.J. Eslep, Capability and Limitation Study of DDT Passive- Active Neutron Waste Assay Instrument, Los Alamas National Laboratory. LA- 12237- MS, Los Alamas, 1992.
  15. K. Okumura, K. Kaneko, K. Tsuchihashi, SRAC95; General Purpose Neutronics Code System, JAERI-Data/code 96-015, Japan Atomic Energy Research Institute, 1996.
  16. T. Nakagawa, et al., Japanese evaluated nuclear data library version 3 revision-2: JENDL-3.2, J. Nucl. Sci. Technol. 32 (1995) 1259.