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Title: Sensitivity-Uncertainty Based Nuclear Criticality Safety Validation

These are slides from a seminar given to the University of Mexico Nuclear Engineering Department. Whisper is a statistical analysis package developed to support nuclear criticality safety validation. It uses the sensitivity profile data for an application as computed by MCNP6 along with covariance files for the nuclear data to determine a baseline upper-subcritical-limit for the application. Whisper and its associated benchmark files are developed and maintained as part of MCNP6, and will be distributed with all future releases of MCNP6. Although sensitivity-uncertainty methods for NCS validation have been under development for 20 years, continuous-energy Monte Carlo codes such as MCNP could not determine the required adjoint-weighted tallies for sensitivity profiles. The recent introduction of the iterated fission probability method into MCNP led to the rapid development of sensitivity analysis capabilities for MCNP6 and the development of Whisper. Sensitivity-uncertainty based methods represent the future for NCS validation – making full use of today’s computer power to codify past approaches based largely on expert judgment. Validation results are defensible, auditable, and repeatable as needed with different assumptions and process models. The new methods can supplement, support, and extend traditional validation approaches.
Authors:
 [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States). Nuclear Engineering Dept.
Publication Date:
OSTI Identifier:
1325663
Report Number(s):
LA-UR--16-27172
TRN: US1700004
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA). Nuclear Criticality Safety Program
Contributing Orgs:
Univ. of New Mexico, Albuquerque, NM (United States)
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICS AND COMPUTING; 42 ENGINEERING; 22 GENERAL STUDIES OF NUCLEAR REACTORS; SENSITIVITY ANALYSIS; VALIDATION; CRITICALITY; MONTE CARLO METHOD; SAFETY; FISSION; W CODES; M CODES; PROBABILITY; WEIGHTING FUNCTIONS; DATA COVARIANCES; ADJOINT FLUX; NEUTRON TRANSPORT MCNP; Monte Carlo