Douglas E. Peplow Nuclear Engineer Radiation Transport Group Reactor and Nuclear Systems Division Oak Ridge National Laboratory
Official ORNL Badge Photo

Current Research

• SCALE Development
  Part of the development team for ORNL's computer package SCALE (Standardized Computer Analyses for Licensing Evaluation). Currently developing the new sequence, MAVRIC, and the functional module Monaco.

  The MAVRIC sequence (Monaco with Automated Variance Reduction using Importance Calculations) will perform radiation transport on problems that are too challenging for standard, unbiased Monte Carlo methods. The intention of the sequence is to calculate fluxes and dose rates with low uncertainties in reasonable times even for deep penetration problems. MAVRIC is based on the CADIS (Consistent Adjoint Driven Importance Sampling) methodology, which uses an importance map and biased source that are derived to work together. MAVRIC uses CSAS/ICE to generate cross sections for the materials input by the users. MAVRIC will then automatically perform a coarse mesh, three-dimensional, discrete ordinates calculation using Denovo to determine the adjoint flux as a function of position and energy. This adjoint flux information is then used by MAVRIC to construct a space and energy-dependent importance map (i.e., weight windows) to be used for biasing during particle transport and a mesh-based biased source distribution. MAVRIC then passes the importance map and biased source distribution to the functional module Monaco, a three-dimensional, fixed-source, multi-group shielding code. In addition to materials input, the user will also supply the geometry description using the SCALE General Geometry Package; source description as a function of position, energy and direction; tally descriptions (fluxes in which regions, at what point detectors, or over what mesh grids); response functions (function of energy); planes for the mesh used by Denovo; and which tally to use as the Denovo adjoint source. Output consists of tables detailing the region and point detector fluxes (and their responses), as well as files for mesh tallies.

Past Research

• Medical Applications
  Various projects using Monte Carlo particle transport in the analysis of radiation treatment planning and diagnostic imaging. Working with the Computational Medical Physics Working Group (CMPWG) to expand the role of computational nuclear engineers into medical applications.

• Facility Vulnerabiltiy
  Worked with Robert H. Morris's Facility Vulnerabiltiy team of the Computational Sciences and Engineering Division to develop VISAC) - the Visual Interactive Site Analysis Code. This code can be used to analyze nuclear power plants or other facilities for vulnerability to blasts. The code works by coupling a detailed geometry model of the plant components and an event/fault tree logic model of the plant safety systems connectivity. More info on VISAC and the facility vulnerability work can be found at visac.ornl.gov.

  VISAC can be used with HPAC, Hazard Predicition and Assessment Capability, developed by Oak Ridge National Laboratory. HPAC is a material transport code used for the analysis of biological, chemical or nuclear releases. More info on HPAC can be found here. This work is sponsored by the Defense Threat Reduction Agency and the Defense Intelligence Agency.

Education

• PhD Nuclear Engineering in May 1999 from N.C. State University
  Advisor: Prof. Kuruvilla Verghese
• MS Nuclear Engineering in December 1993 from N.C. State University
  Advisors: Prof. Robin P. Gardner and Prof. Kuruvilla Verghese
• BS Physics in May 1991 from Western Illinois University

Paper Archive

• See the archive of published papers, posters, presentations, etc.

Contact Information:

email:   peplowde@ornl.gov
web:     http://www.ornl.gov/~5pe
tele:    (865) 574-0521
fax:     (865) 576-3513
post:    BLDG 5700  MS 6172
         PO Box 2008
         Oak Ridge, TN  37831

The last major update of this page was on 20110202.