ANS 2015 Winter Meeting

Washington, D.C. • Nov 8-12, 2015

Special Panel Session—The Legacy of NCS Pioneer Joe Thomas

Joe Thomas, nuclear criticality safety pioneer, passed away in January 2014 at age 87. His contributions in nuclear criticality safety spanned over 5 decades at all three Oak Ridge Facilities, as well as at national and international sites. He was a past Chair of the NCSD, and recipient of the NCSD Distinguished Service Award, as well as ANS Fellow. The work and memory of Joe is marked by a special panel session where individuals have been sought to provide a brief account of their recollections with Joe and/or the impact of his work on modern criticality safety practice.


  • Joe Thomas–”In his own words”
  • Doug Bowen (ORNL)
  • Calvin Hopper (ORNL)
  • Tom McLaughlin (Retired)
  • Richard Taylor (C. S. Engineering) • Mike Westfall (ORNL)

Data, Analysis and Operations in Nuclear Criticality Safety

Reflector Worth of Dry Chemical and Powder Fire Extinguishing Agents, A. R. Wysong, B. S. Chapman (LANL)

ANSI/ANS-8.12 Revision: Selection of MOX Critical Experiments and Preliminary Validation Results, Christopher S. Tripp, Debdas Biswas (LLNL)

A Note on Boundary Conditions and Sources for Analytical Benchmarks, Barry Ganapol (Univ of Arizona), Forrest Brown (LANL)

The 2015 Edition of the ICSBEP Handbook, John D. Bess (INL), Jim Gulliford (OECD NEA)

Results of Partially-Reflected Critical Experiments in Square-Pitched Arrays of Water-Moderated 6.9 Percent Enriched Fuel Rods, Gary A. Harms, John T. Ford, Rafe D. Campbell (SNL)

Reactivity Worth Studies Associated with a Rossi-α Measurement System, George E. McKenzie, Theresa E. Cutler, Travis J. Grove, William L. Myers, Rene G. Sanchez (LANL)

Recent Nuclear Criticality Safety Program Accomplishments (Dedicated to Adolf Garcia)

New NCSP Contributions to ICSBEP and DICE, David Heinrichs (LLNL), Ian Hill (OECD/NEA)

Design of Two New Critical Experiments, C. Percher, S. Kim, D. Heinrichs (LLNL)

MCNP Progress and Performance Improvements, Forrest B. Brown, Jeffrey S. Bull, Michael E. Rising  (LANL)

Analysis of Thermal Neutron Scattering in Polymethyl Methacrylate (Lucite), A. I. Hawari, A. Petersen, Y. Zhu, J. L. Wormald (NCSU), D. P. Heinrichs (LLNL), M. L. Zerkle (BAPL)

SAMINT: A New Evaluation Tool to Perform Resonance Parameter Data Adjustments based on Integral Experiment Data, Vladimir Sobes, Luiz Leal, Goran Arbanas, Marco Pigni (ORNL)

The DOE Criticality Safety Support Group—A Retrospective Perspective, Fitz Trumble (URS Corporation), David Erickson (Savannah River Nuclear Solutions)

NDA Issues Affecting Nuclear Criticality Safety–Panel

The session topic will be the non-destructive assay (NDA) issues that affect the criticality safety of fissile material operations. The structure will be presentations by NDA specialists on current issues with modelling schemes to estimate the amount of fissile material from in-situ measurements and presentations from criticality safety specialists on how they handle the uncertainty in NDA measurements in determining safety limits and controls. Recent examples of NDA non-conservative measurements and how these complicated the evaluation process will be discussed. The presenters will then form a panel to discuss issues and propose solutions.


  • Bob Wilson (DOE/EM)
  • Jeff Chapman (ORNL)
  • Doug Bowen (ORNL)
  • David Dolin (SRNL)
  • John Winkel (CMH2-Hill, Hanford)
  • Jeff Sanders (INL)

ANS-8 Standards