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All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

Regression Suite Improvements in MPACT

As the MPACT code has matured, the regression and validation base has grown significantly. However, the code is still undergoing advancements to the underlying methods, and improvements to the code have the possibility to change the solution. These types of methodological or data improvements should be encouraged but the requirement to rebaseline the entire regression and validation suite has recently become a daunting task which has made it more difficult to make improvements to the code. One of the objectives of this work is to streamline this process but also to provide diagnostics on the significance of the modification and the impact on several quantities of interest.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2017

Development of Transient MPACT-CTF Capability for RIA with DNB

The objective of this milestone was to continue the development, implementation, verification, and validation of the methods in VERA-CS necessary to solve the whole-core time-dependent neutron transport equations with pin-resolved detail for a practical PWR applications. This capability is necessary to provide the time dependent pin resolved neutron flux for analysis of the Reactivity Insertion Accident (RIA) as specified in the CASL RIA Challenge Problem Implementation Plan, CASL-I-2013-0060-000. The FY17 work reported here continued the FY16 work reported in CASL-U-2016-1188-000 which was primarily focused on MPACT and performed the methods, and Validation and Verification (V&V) efforts necessary to demonstrate the transient capability in VERA-CS in order to facilitate the L1 RIA milestone in FY18. This report describes the activities performed in FY17 in the three general areas of: User Support, Methods Improvements, and in V&V and Demonstration. In the area of User Support various user requested features were added to the code such as detailed reactivity edits and improvements to the VERA input. In the area of Methods Improvements, the features added included user controlled variable time stepping, a one-group CMFD Acceleration, and a Delayed Energy Deposition model; as well as improvements to the overall code robustness for the transient solution. In the area of V&V, the full suite of C5G7 Transient benchmarks was completed and significant progress was made on the solution of SPERT with VERA-CS. In the area of practical demonstration, a full core AP1000 demonstration problem was performed with VERA-CS. The work performed in FY17 enhanced the capability of performing VERACS transients for practical large-scale light water reactor problems with an acceptable computational burden and provided an important step in the completion of the CASL Reactivity Insertion Accident (RIA) Challenge Problem.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Reassessment of Boiling Water Reactor Rod Cusping Capability of VERA-MPACT

This technical report assesses the current modeling capabilities of the Virtual Environment for Reactor Applications (VERA) for minimizing control rod cusping in boiling water reactors. Assessment is performed on a 10 × 10 General Electric (GE)-14 assembly as well as a simplified version of the same assembly. Runs were performed using VERA for three available cusping treatments in the Michigan PArallel Characteristics Transport (MPACT) code: no treatment, subplane treatment, and fitted polynomial correction treatment. Subplane treatment is discussed, but specific results are not provided because of failures in the method of implementation for boiling water reactors.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2015

Regression Suite Improvements in MPACT

As the MPACT code has matured, the regression and validation base has grown significantly. However, the code is still undergoing advancements to the underlying methods, and improvements to the code have the possibility to change the solution. These types of methodological or data improvements should be encouraged but the requirement to rebaseline the entire regression and validation suite has recently become a daunting task which has made it more difficult to make improvements to the code. One of the objectives of this work is to streamline this process but also to provide diagnostics on the significance of the modification and the impact on several quantities of interest.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2015

Babcock & Wilcox Critical Experiment Calculations to Support MPACT Verification

This report describes a series of benchmark calculations performed using the method of characteristics radiation transport code MPACT to verify its radial transport and axial buckling calculation capabilities. The benchmarks are based on a series of Babcock & Wilcox critical assembly configurations analyzed in what are commonly known as the B&W-1484 benchmark experiment and the B&W-1810 benchmark experiment.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2017

Molten Salt Reactor Simulation Capability Using MPACT

The recent interest in molten salt reactor technology by the nuclear industry has sparked significant interest in developing modeling and simulation tools for molten salt reactors. The MPACT whole core transport solver has been adapted to address several unique features of molten salt reactors. This paper discusses implementation of a depletion methodology which simulates the mixing of fuel throughout the core, the continuous removal of fission products, and the continuous addition of new fuel into the system. It also presents the methodology used to treat the transport of delayed neutron precursors. These new methods are demonstrated using models based on Transatomic Power Corporation’s molten salt reactor design.

Collins, Benjamin↗
DOE OSTI2021

University Research to Support the MPACT 2020 Milestone

University research is a strong focus of the Office of Nuclear Energy within the Department of Energy. This research complements existing work in the various program areas and provides support and training for students entering the field. Four university projects have provided support to the Material Protection Accounting and Controls Technologies (MPACT) 2020 milestone focused on safeguards for electrochemical processing facilities. The University of Tennessee Knoxville has examined data fusion of NDA measurements such as Hybrid K-Edge Densitometry and Cyclic Voltammetry. Oregon State University and Virginia Polytechnic Institute have examined the integration of accountancy data with process monitoring data for safeguards. The Ohio State University and the University of Utah have developed a Ni-Pt SiC Schottky diode capable of high temperature alpha spectroscopy for actinide detection of molten salts. Finally, the University of Colorado has developed a key enabling technology for the use of Microcalorimetry.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

PTM‐Psi : A python package to facilitate the computational investigation of p ost‐ t ranslational m odification on p rotein s tructures and their i mpacts on dynamics and functions

Abstract Post‐translational modification (PTM) of a protein occurs after it has been synthesized from its genetic template, and involves chemical modifications of the protein's specific amino acid residues. Despite of the central role played by PTM in regulating molecular interactions, particularly those driven by reversible redox reactions, it remains challenging to interpret PTMs in terms of protein dynamics and function because there are numerous combinatorially enormous means for modifying amino acids in response to changes in the protein environment. In this study, we provide a workflow that allows users to interpret how perturbations caused by PTMs affect a protein's properties, dynamics, and interactions with its binding partners based on inferred or experimentally determined protein structure. This Python‐based workflow, called PTM‐Psi , integrates several established open‐source software packages, thereby enabling the user to infer protein structure from sequence, develop force fields for non‐standard amino acids using quantum mechanics, calculate free energy perturbations through molecular dynamics simulations, and score the bound complexes via docking algorithms. Using the S ‐nitrosylation of several cysteines on the GAP2 protein as an example, we demonstrated the utility of PTM‐Psi for interpreting sequence–structure–function relationships derived from thiol redox proteomics data. We demonstrate that the S ‐nitrosylated cysteine that is exposed to the solvent indirectly affects the catalytic reaction of another buried cysteine over a distance in GAP2 protein through the movement of the two ligands. Our workflow tracks the PTMs on residues that are responsive to changes in the redox environment and lays the foundation for the automation of molecular and systems biology modeling.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2016

Report on MPACT Deliverable M3FT-16LA040106035 (High Dose Evaluation of Improved PDT Detector Pod)

This report provides the results for the initial high gamma dose tests for the boron-10 plate detector that was fabricated by PDT, Inc. under contract to LANL The specifications for the detector were developed using MCNP code simulations and prior experimental tests at LANL. The goal in the development was to provide high neutron detection efficiency together with gamma-ray resistance at very high gamma dose levels that are characteristic of the electrochemical fuel processing activity.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗