U.S. Nuclear Criticality Safety Program (NCSP)

January, 2017

Overview of the U.S. Nuclear Criticality Safety Program (NCSP) (hi-res image)

Problem Statement

Technology infrastructure needed to enable sites to perform safe, efficient fissionable material operations in the DOE Complex.

Technical Approach

ORNL has lead-lab responsibility to support the NNSA in management and execution of the NCSP that is organized by 5 technical program elements:

Sandia Pulse Reactor (SPR) Facility Experiments (hi-res image)

•Nuclear Data

  • Perform measurement, evaluation, testing and publication of neutron cross-section data for nuclides of high importance to nuclear criticality safety.
•Analytical Methods
  • Provides for the development and maintenance of state-of-the-art capabilities for processing of nuclear data from Evaluated Nuclear Data File (ENDF) and the radiation transport analysis capabilities needed to perform nuclear criticality safety analyses.
•Information Preservation & Dissemination
  • Preserve primary documentation supporting criticality safety (e.g., benchmark critical experiments from the International Criticality Safety Benchmark Evaluation Project (ICSBEP) and makes this information available for the benefit of the technical community including international partners (e.g., AWE, CEA, and OECD) through the NCSP website (
•Integral Experiments
  • To sustain and enhance a fundamental nuclear materials handling capability to conduct subcritical, critical, supercritical, prompt critical, super-prompt critical, fundamental physics experiments and training.
    Comet Critical Assembly (NCERC) (hi-res image)
  • Experiments are conducted with fissionable materials and critical assemblies at the Nevada Critical Experiments Research Center (NCERC) and at the Sandia National Laboratory Pulse Reactor (SPR) Facility.
  • The NCSP Integral Experiments program serves as a national and international resource, providing a sustainable infrastructure including a systematic, interactive process to assess, design, perform, and document nuclear material experiments and training. 

Flattop Critical Assembly (NCERC) (hi-res image)

•Training & Education
  • ​Identify, develop, provide, and promote practical and excellent technical training and educational resources that help ensure competency in the art, science, and implementation of nuclear criticality safety (NCS).
  • This training satisfies NCS American National Standards Institute/American Nuclear Society consensus standard 8.26-2007 requirements for NCS staff participation in hands-on experiments with fissionable materials. The training also provides a discussion of process criticality accidents and an overview of the Nuclear Criticality Safety Evaluation (NCSE) development process. 
  • One and two-week courses have been developed to train NCS engineers, process supervisors, and managers with NCS responsibilities on the development and important of NCSEs. 


Maintains the technical infrastructure necessary to ensure safe, efficient fissionable material operations from a nuclear criticality safety perspective.


U.S. Department of Energy, Nuclear Criticality Safety Program

Project Manager

Douglas G. Bowen