Nuclear Engineering Division

Fissile Material Disposition (MD)

Safe disposition of excess weapons plutonium through reactor irradiation and conversion to spent fuel.


The end of the Cold War has created a legacy of surplus fissile materials (primarily weapons-grade plutonium and highly enriched uranium) in the United States and the former Soviet Union. These materials pose a risk to national and international security. The NE Division is supporting DOE-NNSA efforts to identify, assess and implement reactor disposition options to ensure that these surplus fissile materials are not utilized in nuclear weapons.

Research in the NE Division is focused on fast reactor-based plutonium disposition options and strategies for Russia. Argonne is working with ORNL and Russian research institutes, industrial organizations, nuclear power plant owner/operators, and Russian nuclear safety regulators to develop, demonstrate, and license the technologies and facilities required to implement plutonium disposition in fast reactors (primarily BN-600).

NE activities include:

  • Transfer of safety analysis capabilities to Russian organizations.
  • Training of Russian analysts in the use of fast reactor safety analysis tools developed at Argonne.
  • Execution of independent assessments of physics and core design issues, e.g.,
    • Fuel cycle analysis of BN-600 core configurations employing plutonium-bearing fuels.
    • Performance and shielding issues associated with elimination of blanket assemblies.
    • Fresh and spent fuel dose rates and fuel handling implications
  • Performance of independent safety analyses using the SASSYS/SAS4A Argonne code systems.
    Unprotected Loss of Flow Transient in BN-600

    Unprotected Loss of Flow Transient in BN-600. Click on image to view larger image.

    • Assessment of the impact of partial or full loadings of plutonium fuel on reactor dynamic response and behavior in postulated accident sequences.
    • Assessment of safety impacts of alternative fuel types (e.g., vibrocompacted mixed oxide fuel).
  • Review of Russian reports on design, safety and fuel performance aspects of plutonium burning in fast reactors.

Last Modified: Thu, April 21, 2016 4:44 AM



  • SASSYS - Software designed to perform deterministic analysis of design basis and beyond-design basis accidents in liquid metal cooled reactor (LMR) plants
  • SAS4A - Software designed to perform deterministic analysis of severe accidents in liquid metal cooled reactors (LMRs)

For more information:

Advanced Modeling, Simulation and Licensing
Program Manager: Tanju Sofu
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T. Sofu's Executive Bio

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Nuclear Engineering Division
Deputy Director: Temitope Taiwo
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