Research Programs

Nuclear Fuel Cycle

Publications:

  1. S.M. Oggianu and M.S. Kazimi, A Review of Properties of Advanced Nuclear Fuels, MIT-NFC-TR-021 (February 2000).
  2. S.M. Oggianu, H.C. No, and M.S. Kazimi, Performance Indices for Advanced Nuclear Fuel Materials, ANS/ENS 2000 International Winter Meeting, Washington D.C. (November 12-16, 2000).
  3. Z. Xu, M. Driscoll, and M.S. Kazimi, Proliferation and Waste Disposal Characteristics of High-Burnup UO2 Fuel In Water Cooled Lattices, ANS/ENS 2000 International Winter Meeting, Washington D.C. (November 12-16, 2000).
  4. Z. Xu, M. Driscoll, and M.S. Kazimi, Effect of Moderator-To-Fuel Ratio On High-Burnup Potential In UO2-Fueled Water/Stream Cooled Lattices, ANS/ENS 2000 International Winter Meeting, Washington D.C. (November 12-16, 2000).
  5. S.M. Oggianu, M.S. Kazimi, and H.C. No, High Burnup Fuels for Advanced Nuclear Reactors, MIT-NFC-TR-029 (May 2001).
  6. Z. Xu, M.J. Driscoll, and M.S. Kazimi, Systematic Study of Moderation Effects on UO2 Fueled Lattices, MIT-NFC-TR-028 (May 2001).
  7. Y. Long, Y. Yuan, Mujid S. Kazimi, R. G. Ballinger, and E.E. Pilat, A Fission Gas Release Model for High Burnup LWR ThO2-UO2 Fuel, Nuclear technology, Vol 138 (June 2002).
  8. Z. Xu, M.J. Driscoll, and M.S. Kazimi, Neutron Spectrum Effects on Burnup, Reactivity and Isotopics in UO2/H2O Lattices, Nuclear Science & Engineering, Vol 141 (3) (July 2002).
  9. Y. Long, R.G. Ballinger, J.E. Meyer, and M.S. Kazimi, RIA Investigation for High Burnup ThO2-UO2 Fuel, ANS Annual Meeting (June 2002).
  10. Z. Xu, P. Hejzlar, M.J. Driscoll, and M.S. Kazimi, An Improved MCNP-ORIGEN Depletion Program (MCODE) and its Verification for High Burnup Applications, PHYSOR, Seoul, Korea (October 7-10, 2002).
  11. S.M. Oggianu, H.C. No, and M.S. Kazimi, Analysis of Burnup and Economic Potential of Alternative Fuel Materials in Thermal Reactors, Nuclear Technology, Vol 142 (September 2003).

Investigators :

  • Profs. M.S. Kazimi and M. J. Driscoll, Drs. E. E. Pilat, H. C. No and P. Hejzlar, Mrs. Z. Xu, S. Oggianu, Y. Long, and Yi Yuan.

High Burnup LWR Fuel Modeling and Optimization

One primary initiative of optimizing the LWR fuel cycle is to improve the fuel utilization, i.e., to increase the fuel burnup. Historically, the average increase of discharge burnup in the 1990s has been about 1 MWd/kg per year for PWRs, which was mainly achieved by increasing the average reload enrichment. The front-end fuel cycle requirements, including the separative work and natural uranium ore requirements, have been reduced as burnup increased. However, due to a weak optimum of natural uranium utilization around 5 w/o enrichment, there are not as strong incentives as before to push for higher burnup from the front-end of the fuel cycle. However, increasing the capacity factor by reducing the refueling frequency and more recently, limited spent fuel storage capacity have induced the utilities to examine achieving burnup in the 70 to 100 MWd/kg range in LWRs. Neutronic investigations show that the reactivity-limited burnup potential is affected largely by the hydrogen-to-heavy-metal ratio. Either wetter or very dry UO2/H2O lattices are preferable to those having an epithermal spectrum. Higher fuel burnup is beneficial to enhancing the proliferation resistance (worse plutonium vector in the spent fuel) as well as reducing the total volume and possibly the heat load of the spent fuel per unit energy generation.

High burnup has a significant impact on fuel performance requirements. For example, an increase of fission gas release is expected as burnup increases. Fuel pin design needs to be properly revised to incorporate the changes of thermal, mechanical, and material responses of fuel rods at high burnup under both the steady-state operations and transient conditions. A review of potential fuel materials has been conducted. The steady-state NRC fuel performance code, FRAPCON-3, was revised to extend the fuel burnup range for both UO2 and ThO2. A revision of the transient fuel modeling code, FRAPTRAN, is underway.

There are several distinct high-burnup core management schemes, among which the long cycle core is one interesting option under current investigation as described by other projects in the activities report.