“Criticality Safety – pushing boundaries by modernizing and integrating data, methods, and regulations”

Organized by:

ANS Nuclear Criticality Safety Division (http://ncsd.ans.org)
American Nuclear Society (http://www.ans.org)

Proud Sponsors:

Four Tutorials are offered to the attendees who register to the conference. Participants to the Tutorial of their choice will have to sign up at the time of registration, and pay the corresponding participation fee. No reimbursement will be processed in the case of cancellation. 

The Tutorials will all be held on Sunday September 10, 2017, at the site of the conference (Pecos River Village Conference Center). 

Please click on each Tutorial below for more information:

A. Automated As-loaded and Design-basis Criticality Analysis for Dry Spent Nuclear Fuel Systems Using UNF-ST&DARDS

B. Monte Carlo Criticality Calculations with MCNP6-Whisper

C. Performing Criticality Evaluations in Geologic Repositories

D. SCALE 6.2 Criticality Safety Calculations and Sensitivity/Uncertainty Methods for Criticality Safety Validation


A. Automated As-loaded and Design-basis Criticality Analysis for Dry Spent Nuclear Fuel Systems Using UNF-ST&DARDS

Organizer: Kaushik Banerjee (ORNL)

Description: The Used Nuclear Fuel-Storage, Transportation & Disposal Analysis Resource and Data System (UNF-ST&DARDS) is being developed at Oak Ridge National Laboratory in collaboration with multiple national laboratories and nuclear industry participants (utilities, fuel vendors, and cask vendors) for integrating spent nuclear fuel (SNF) management through its final disposition. When basic information about the SNF and the cask system is provided, the data relationships defined in UNF-ST&DARDS allow inputs to the respective codes (e.g., SCALE) to be built autonomously. This tutorial will include (1) as-loaded (using actual cask loading maps) criticality analysis of currently loaded casks for storage, transportation, and disposal (over disposal time periods), (2) discussion of as-loaded criticality analysis to support licensing/certification of dry SNF systems, (3) misload analysis methodology to support as-loaded criticality analysis, and (4) design-basis criticality analysis using user-defined loading patterns and fuel assembly types.

Current restrictions to users:  Laptops are not required, but participants with valid licenses for UNF-ST&DARDS 3.1Beta (by invitation only) and SCALE 6.2.2 installed on their computer (windows machine) can follow the demonstrations hands-on.

Length: Half-Day (1pm to 5pm)

Participation fee: $15 (includes: refreshments)


B. Monte Carlo Criticality Calculations with MCNP6-Whisper

Organizers: Forrest Brown, Jennifer Alwin, Michael Rising (LANL)


Review of MC criticality fundamentals (9am - 11am)

This portion of the tutorial session is targeted at new or early-career criticality safety analysts to provide a review of basic concepts, including: best practices for MC criticality calculations, spectra, lethargy, sensitivity, nuclear data uncertainties, etc.

What’s new with MCNP6.2 & Whisper-1.1 (11am – 12pm)

An update on what is the same or different with the Spring 2017 release of MCNP6.2 & Whisper-1.1.

Tutorial on using MCNP6-Whisper-1.1 for NCS validation (1pm – 5pm)

Whisper-1.1 makes use of MCNP6-generated sensitivity profiles and cross-section covariance data to provide guidance for setting baseline USLs for NCS validation. Background & practical application of the new tool will be covered, along with discussion of ANS standards.  Discussion time will be available for specific issues concerning installation, problem resolution, user issues, computational details, etc. Laptops are not required, but participants with laptops & installed MCNP6 can follow the demonstrations hands-on.

Length: Full-Day (9am to 5pm)

Participation fee: $40 (includes: refreshments, lunch)


C. Performing Criticality Evaluations in Geologic Repositories

Organizer: John Scaglione (ORNL)

Description: Strategies for the back end of the fuel cycle continue to be developed, but the fundamental objectives for disposal in any geologic repository are the same — the safety of workers and the public, and long-term isolation of the radioactive materials from the biosphere. Achieving these objectives will include addressing criticality and other potential disruptions after waste emplacement under geologic disposal conditions and time frames. Ultimately the repository’s ability to perform is evaluated through a total performance assessment (PA).  A PA is an analysis that identifies features, events, and processes (FEPs) and sequences of events and processes that might affect the total disposal system, including both natural and engineered systems, and their probabilities of occurring. The total probability of criticality includes contributions associated with both internal (within the waste package) and external (external to the waste package) criticality. This tutorial provides an overview of selected technical studies, methods, and considerations developed to support geologic repository criticality analyses including those performed for Yucca Mountain and potential other host geologies. Topics that will be reviewed and discussed include scenario development, relationships between natural and engineered barriers, burnup credit, misload analysis, computational validation, criticality control options, and development of conservative yet realistic application model(s). 

Length: Half-Day (1-5pm)

Participation fee: $15 (includes: refreshments)


D. SCALE 6.2 Criticality Safety Calculations and Sensitivity/Uncertainty Methods for Criticality Safety Validation

Organizer: Chris Perfetti (ORNL)

Description: This course will cover the theory and use of tools in the SCALE 6.2 Code Package for criticality safety calculations and sensitivity/uncertainty-informed criticality safety validation.  The first half of the course will provide instruction on performing criticality safety calculations using the KENO-VI code, a 3-D generalized geometry Monte Carlo code that allows for versatile modeling of complex geometries using either continuous-energy or multigroup physics. This class will use the Fulcrum user interface for interactive model setup, visualization of inputs and results, execution of SCALE, and output review.  Instruction will also be provided on the SCALE material input and resonance self-shielding capabilities, including Fulcrum capabilities for visualizing fluxes, reaction rates, and cross-section data.  By the end of the first half of this course, users will understand the basic steps involved in building KENO-VI geometries and will develop KENO models for several simple systems.  More experienced users are encouraged to attend and develop more complicated models for their applications of interest.

The second half of this course will focus on SCALE sensitivity and uncertainty methods for criticality safety validation.  This block will begin by discussing the TSUNAMI-3D methods for sensitivity analysis, and will discuss sensitivity coefficient calculations for eigenvalue responses using continuous-energy physics models.  This course will then discuss SCALE’s comprehensive library of cross-section covariance data, which can be used to estimate the uncertainty present in eigenvalues and other system responses when combined with TSUNAMI sensitivity coefficients.  An alternate approach for uncertainty quantification will also be presented using the SAMPLER tool, which allows for uncertainty analysis by randomly sampling cross section data, geometry information, and other parameters.  This course will conclude by briefly discussing how sensitivity and uncertainty analysis methods enable advanced techniques for code and data validation, including the identification of appropriate benchmark experiments, detailed quantification of bias and bias uncertainty, and identification of gaps in available experiments.

The tutorial is open to all conference attendees.  Participants wishing to follow along with the tutorial should bring their own computer, have a valid license for SCALE 6.2.0 or a more recent version, and have this SCALE version installed on their computer.

Length: Full-Day (8am to 5pm)

Participation fee: $40 (includes: refreshments, lunch)