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SCALE is a comprehensive modeling and simulation suite for nuclear safety analysis and design developed and maintained by Oak Ridge National Laboratory under contract with the U.S. Nuclear Regulatory Commission, U.S. Department of Energy, and the National Nuclear Security Administration to perform reactor physics, criticality safety, radiation shielding, and spent fuel characterization for nuclear facilities and transportation/storage package designs.

SCALE Users' Group Workshop 2019 

The 3rd SCALE Users' Group Workshop will be hosted by Oak Ridge National Laboratory on August 19-21, 2019. The workshop will provide a highly interactive forum for a fruitful exchange between SCALE users and developers and will include a mix of technical presentations, open discussions, and tutorial sessions. The meeting is free of charge for students, with a $250 registration fee charged for professionals. Working lunch and refreshments will be provided to participants. An evening poster session and reception will be held on the first day of the meeting.

You are invited to participate in the meeting and contribute with presentations on impactful and innovative applications of SCALE. Registration is open at .

SCALE 6.2.3 Update

The SCALE 6.2.3 update is available to update your existing SCALE 6.2.0, 6.2.1, or 6.2.2 installation. SCALE 6.2.3 provides enhanced features and performance in the areas detailed below. SCALE 6.2.3 incorporates all updates made since the SCALE 6.2.0 release so that users can proceed directly to the SCALE 6.2.3 update, even if previous updates have not been applied.

Enhancements in SCALE 6.2.3 are summarized below, with additional details available here.

  • An issue was identified in SCALE 6.1–6.2.2 with KENO-V.a in which unexpected behavior occurs if the input assigns albedo boundary conditions to a non-cuboid region, contrary to the documentation, which states “Albedo boundary conditions are applied only to the outermost region of a problem. In KENO V.a this geometry region must be a rectangular parallelepiped.” This error is now properly caught by input checking in SCALE 6.2.3.
  • Polaris was updated to include pressurized and boiling water reactor (PWR/BWR) detector modeling capability.
  • Polaris depletion runtimes were decreased by a factor of ~2 for calculations with small burnup steps.
  • Polaris was updated to robustly handle simultaneous density and soluble boron changes in the moderator and coolant.
  • ORIGEN was updated to show delayed neutron emitters in neutron emission output tables, even if only present at the initial time.
  • TRITON was corrected to include thorium as a heavy metal for burnup and power definitions.
  • A change in the 6.2 TRITON handling of swap materials that may cause unexpected behavior in some 6.1 inputs has been recognized and documented (see SCALE Newsletter Number 51, Spring 2018).
  • The multigroup cross section self-shielding method selection logic (BONAMI or CENTRM) includes improved consistency across all sequences and now enables the use of BONAMI-only methodology for faster calculations or for cases in which the CENTRM methodology is not suitable.
  • Numerous other stability, usability, and documentation enhancements are also included.

To request the SCALE 6.2.3 update, please email us at

To view the previous SCALE Updates, please click here.

Read the Fiscal Year 2017 Report on SCALE Maintenance and Development

SCALE User Notice - March 8, 2018