Search NASA⌕ Search

SEARCH · Search NASA

Results for “Rattlesnake”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Preliminary Results for the OECD/NEA Time Dependent Benchmark using Rattlesnake, Rattlesnake-IQS and TDKENO

One goal of the MAMMOTH M&S project is to validate the analysis capabilities within MAMMOTH. Historical data has shown limited value for validation of full three-dimensional (3D) multi-physics methods. Initial analysis considered the TREAT startup minimum critical core and one of the startup transient tests. At present, validation is focusing on measurements taken during the M8CAL test calibration series. These exercises will valuable in preliminary assessment of the ability of MAMMOTH to perform coupled multi-physics calculations; calculations performed to date are being used to validate the neutron transport solver Rattlesnake\cite{Rattlesnake} and the fuels performance code BISON. Other validation projects outside of TREAT are available for single-physics benchmarking. Because the transient solution capability of Rattlesnake is one of the key attributes that makes it unique for TREAT transient simulations, validation of the transient solution of Rattlesnake using other time dependent kinetics benchmarks has considerable value. The Nuclear Energy Agency (NEA) of the Organization for Economic Cooperation and Development (OECD) has recently developed a computational benchmark for transient simulations. This benchmark considered both two-dimensional (2D) and 3D configurations for a total number of 26 different transients. All are negative reactivity insertions, typically returning to the critical state after some time.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2015

Year End Progress Report on Rattlesnake Improvements

Rattlesnake is a MOOSE-based radiation transport application developed at INL to support modern multi-physics simulations. At the beginning of the last year, Rattlesnake was able to perform steady-state, transient and eigenvalue calculations for the multigroup radiation transport equations. Various discretization schemes, including continuous finite element method (FEM) with discrete ordinates method (SN) and spherical harmonics expansion method (PN) for the self-adjoint angular flux (SAAF) formulation, continuous FEM (CFEM) with SN for the least square (LS) formulation, diffusion approximation with CFEM and discontinuous FEM (DFEM), have been implemented. A separate toolkit, YAKXS, for multigroup cross section management was developed to support Rattlesnake calculations with feedback both from changes in the field variables, such as fuel temperature, coolant density, and etc., and in isotope inventory. The framework for doing nonlinear diffusion acceleration (NDA) within Rattlesnake has been set up, and both NDA calculations with SAAF-SN-CFEM scheme and Monte Carlo with OpenMC have been performed. It was also used for coupling BISON and RELAP-7 for the full-core multiphysics simulations. Within the last fiscal year, significant improvements have been made in Rattlesnake. Rattlesnake development was migrated into our internal GITLAB development environment at the end of year 2014. Since then total 369 merge requests has been accepted into Rattlesnake. It is noted that the MOOSE framework that Rattlesnake is based on is under continuous developments. Improvements made in MOOSE can improve the Rattlesnake. It is acknowledged that MOOSE developers spent efforts on patching Rattlesnake for the improvements made on the framework side. This report will not cover the code restructuring for better readability and modularity and documentation improvements, which we have spent tremendous effort on. It only details some of improvements in the following sections.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

Neutronics Modeling of the pulsed plasma rocket reactor using rattlesnake

In the pulsed plasma rocket (PPR) reactor, neutron induced fission processes are utilized to implement a series of pulsed micro-explosions of very high power and eject plasma as a propellant. More specifically, projectiles (bullets) composed of moderated uranium are sent through the chamber of an unmoderated uranium barrel. By inducing rapid fission within the bullets, a plasma can be generated with appropriate delivery of neutrons. This study aims to assess the neutronics performance of the PPR reactor during normal operations using the MOOSE-based Rattlesnake code through the evaluation of the impact of the movement of the fuel bullet and the rotation of control drums on the criticality of the system. The Monte Carlo (MC) code Serpent 2 was employed to generate material-based cross sections for use in Rattlesnake and the reference neutronics solution. Cubit was used to generate the mesh for the Rattlesnake model. Parametric studies were conducted to evaluate the best approaches for cross section and mesh generation to ensure accurate results from Rattlesnake. As part of the verification process, the eigenvalue results of the system at various fuel bullet positions were obtained using Rattlesnake and compared with the reference solutions. The acceptable differences show that the Rattlesnake model with appropriate cross section and mesh generation procedure is a sufficiently accurate approximation of the continuous energy (CE) MC model for micro-sized reactors like the PPR reactor. Next, the impact of the rotation of the control drums on the system criticality was evaluated using the verified model. It was shown that the high-fidelity simulation using the deterministic code Rattlesnake can produce sufficiently accurate results for the evaluation of the reactor's neutronics performance in different phases of the normal operation with acceptable computational cost.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2011

Cultural Resources Monitoring for the Rattlesnake Mountain Combined Community Communications Facility and Infrastructure Cleanup on the Fitzner/Eberhardt Arid Lands Ecology Reserve, 600 Area, Hanford Site, Washington – HCRC# 2008-600-004

Since 1989, cleaning up the Hanford Site has been the primary mission of the U.S. Department of Energy Richland Operations Office (DOE-RL). One cleanup goal is footprint reduction on the Fitzner/Eberhardt Arid Lands Ecology Reserve (ALE). Footprint reduction includes a variety of activities such as the remediation of waste sites, demolition of abandoned buildings and infrastructure, and removal of equipment and miscellaneous debris items. Footprint reduction on the Rattlesnake Mountain ridgeline also included the construction of the Combined Community Communications Facility (CCCF), which combines all communication towers on Rattlesnake Mountain into a single facility. The proposed footprint reduction activities on ALE were covered in several previously completed cultural resources reviews. Two project areas are especially sensitive to cultural resources----the Rattlesnake Mountain ridgeline, a traditional cultural property (TCP), and Rattlesnake Spring, where several National Register-eligible sites are located. The first cultural resource review for this project found that footprint reduction activities would have an adverse effect on Laliik, the Rattlesnake Mountain TCP, by compromising its spiritual qualities and its visual and natural setting. Through consultation among representatives of DOE, the State Historic Preservation Office, and local tribal groups, a number of mitigation strategies were developed to resolve the adverse effects. These strategies focused on minimizing impacts during the construction and operation of the new CCCF and during demolition and cleanup activities. These stipulations were cemented in a Memorandum of Agreement (MOA), signed by the project stakeholders on July 30, 2009. The MOA required intermittent monitoring by qualified archaeologists during construction of the new communications facility and during demolition and removal of debris and infrastructure. Archaeologists with Pacific Northwest National Laboratory performed archaeological monitoring intermittently from August 12, 2009, through May 5, 2011. This report documents all archaeological monitoring conducted for the ALE footprint reduction project in accordance with stipulations outlined in the MOA.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Rattlesnake User's Manual

Rattlesnake is a combined-environments, multiple input/multiple output control system for dynamic excitation of structures under test. It provides capabilities to control multiple responses on the part using multiple exciters using various control strategies. Rattlesnake is written in the Python programming language to facilitate multiple input/multiple output vibration research by allowing users to prescribe custom control laws to the controller. Rattlesnake can target multiple hardware devices, or even perform synthetic control to simulate a test virtually. Rattlesnake has been used to execute control problems with up to 200 response channels and 12 drives. This document describes the functionality, architecture, and usage of the Rattlesnake controller to perform combined environments testing.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Rattlesnake User's Manual (V.3)

Rattlesnake is a combined-environments, multiple input/multiple output control system for dynamic excitation of structures under test. It provides capabilities to control multiple responses on the part using multiple exciters using various control strategies. Rattlesnake is written in the Python programming language to facilitate multiple input/multiple output vibration research by allowing users to prescribe custom control laws to the controller. Rattlesnake can target multiple hardware devices, or even perform synthetic control to simulate a test virtually. Rattlesnake has been used to execute control problems with up to 200 response channels and 24 shaker drives. This document describes the functionality, architecture, and usage of the Rattlesnake controller to perform combined environments testing.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2014

The coupling of the neutron transport application RATTLESNAKE to the nuclear fuels performance application BISON under the MOOSE framework

The MOOSE neutron transport application RATTLESNAKE was coupled to the fuels performance application BISON to provide a higher fidelity tool for fuel performance simulation. This project is motivated by the desire to couple a high fidelity core analysis program (based on the self-adjoint angular flux equations) to a high fidelity fuel performance program, both of which can simulate on unstructured meshes. RATTLESNAKE solves self-adjoint angular flux transport equation and provides a sub-pin level resolution of the multigroup neutron flux with resonance treatment during burnup or a fast transient. BISON solves the coupled thermomechanical equations for the fuel on a sub-millimeter scale. Both applications are able to solve their respective systems on aligned and unaligned unstructured finite element meshes. The power density and local burnup was transferred from RATTLESNAKE to BISON with the MOOSE Multiapp transfer system. Multiple depletion cases were run with one-way data transfer from RATTLESNAKE to BISON. The eigenvalues are shown to agree well with values obtained from the lattice physics code DRAGON. The one-way data transfer of power density is shown to agree with the power density obtained from an internal Lassman-style model in BISON.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2021

Rattlesnake Vibration Controller v.2.0

SAND2021-7300 O The Rattlesnake Vibration Controller is a combined-environments, multiple input/multiple output control system for dynamic excitation of structures under test. It provides capabilities to control multiple responses on the part using multiple exciters and control strategies. Rattlesnake is written in the Python programming language to facilitate multiple input/multiple output vibration research by allowing users to prescribe custom control laws to the controller. Rattlesnake can target multiple hardware devices, or even perform synthetic control to simulate a test virtually. Rattlesnake has been used to execute control problems with up to 200 response channels and 12 drives. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Rohe, Daniel↗
DOE OSTI2014

Initial RattleSnake Calculations of the Hot Zero Power BEAVRS

The validation of the Idaho National Laboratory's next generation of reactor physics analysis codes is an essential and ongoing task. The validation process requires a large undertaking and includes detailed, realistic models that can accurately predict the behavior of an operational nuclear reactor. Over the past few years the INL has developed the RattleSnake application and supporting tools on the MOOSE framework to perform these reactor physics calculations. RattleSnake solves the linearized Boltzmann transport equation with a variety of solution meth­ ods. Various traditional reactor physics benchmarks have already been performed, but a more realistic light water reactor comparison was needed to solidify the status of the code and deter­ mine its fidelity. The INL team decided to use the Benchmark for Evaluation and Validation of Reactor Simulations, which was made available in early 2013. This benchmark is a one­ of-a-kind document assembled by the Massachusetts Institute of Technology, which includes two cycles of detailed, measured PWR operational data. The results from this initial study of the hot zero power conditions show the current INL analysis procedure with DRAGON4 cross section preparation and using the low order diffusion solver in RattleSnake for the whole core calculations yield very encouraging results for PWR analysis. The radial assembly power distributions, radial detector measurements and control rod worths were computed with good accuracy. The computation of the isothermal temperature coefficients of reactivity require further study.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2023

A Review of Rattlesnake Venoms

Venom components are invaluable in biomedical research owing to their specificity and potency. Many of these components exist in two genera of rattlesnakes, Crotalus and Sistrurus, with high toxicity and proteolytic activity variation. This review focuses on venom components within rattlesnakes, and offers a comparison and itemized list of factors dictating venom composition, as well as presenting their known characteristics, activities, and significant applications in biosciences. There are 64 families and subfamilies of proteins present in Crotalus and Sistrurus venom. Snake venom serine proteases (SVSP), snake venom metalloproteases (SVMP), and phospholipases A2 (PLA2) are the standard components in Crotalus and Sistrurus venom. Through this review, we highlight gaps in the knowledge of rattlesnake venom; there needs to be more information on the venom composition of three Crotalus species and one Sistrurus subspecies. We discuss the activity and importance of both major and minor components in biomedical research and drug development.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2018

Multischeme transport with upwinding for Rattlesnake code

This report conclude our efforts at INL to make Rattlesnake, the MOOSE-based radiation multigroup transport application, fully support the multischeme transport capability. Specifically, it details all five types of interface condition with upwinding method for coupling eight available discretization schemes within Rattlesnake. These discretization schemes include SN (discrete ordinates method), PN (spherical harmonics expansion method) and diffusion for angular discretization, and continuous finite element method (CFEM) and discontinuous finite element method (DFEM) for spatial discretization. The other type of method based on Lagrange multipliers for coupling schemes based on CFEM has been studied in the past. Besides simple test problems, a more realistic application of multischeme transport for TREAT (transient reactor test facility) experiment modeling are presented. Several enhancements are reviewed at the end which could potentially be useful in the future.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2017

A Generalized Perturbation Theory Solver In Rattlesnake Based On PETSc With Application To TREAT Steady State Uncertainty Quantification

Rattlesnake and MAMMOTH are the designated TREAT analysis tools currently being developed at the Idaho National Laboratory. Concurrent with development of the multi-physics, multi-scale capabilities, sensitivity analysis and uncertainty quantification (SA/UQ) capabilities are required for predicitive modeling of the TREAT reactor. For steady-state SA/UQ, that is essential for setting initial conditions for the transients, generalized perturbation theory (GPT) will be used. This work describes the implementation of a PETSc based solver for the generalized adjoint equations that constitute a inhomogeneous, rank deficient problem. The standard approach is to use an outer iteration strategy with repeated removal of the fundamental mode contamination. The described GPT algorithm directly solves the GPT equations without the need of an outer iteration procedure by using Krylov subspaces that are orthogonal to the operator’s nullspace. Three test problems are solved and provide sufficient verification for the Rattlesnake’s GPT capability. We conclude with a preliminary example evaluating the impact of the Boron distribution in the TREAT reactor using perturbation theory.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2016

Uncollided Flux Techniques for Discrete-Ordinate Radiation Transport Solutions in Rattlesnake

One of the only real-time-resolved measurement tools used at the Transient Test Reactor (TREAT) is the fast-neutron hodoscope. The hodoscope was used for monitoring and measuring fuel motion during a transient pulse. The hodoscope is a line of sight detection and imaging system that provides both temporal and spatial resolution of fuel motion during transients, and in-place measurement of fuel distribution during and after transient experiments. However, the hodoscope relies on fast neutron streaming out of the reactor core, which provides a challenge to transient modeling and simulation. However, use of a first collision source approach can be used to overcome this shortcoming. Hence, the TREAT modeling and simulation team has initiated research to implement such capabilities in the neutron transport code Rattlesnake. This report reviews uncollided flux techniques (first and last collision methods) to be implemented in the Rattlesnake SN code in order to mitigate ray effects in modeling the TREAT reactor+hodoscope system. Angular discretization techniques (SN and PN) for the transport equation are notoriously poor at capturing effectively streaming effects.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2025

Evaluating Movement Patterns of the Rattlesnake Hills Elk Herd on Hanford for Calendar Years 2019-2024

Biologists first documented elk on the Hanford Site in 1972; since then, the elk herd known as the Rattlesnake Hills Elk Herd (RHEH) has grown substantially (PNNL-13331, Population Characteristics and Seasonal Movement Patterns of the Rattlesnake Hills Elk Herd: Status Report 2000). Through the 1990s, the core range of the RHEH was focused on the portion of the Hanford Reach National Monument known as the Fitzner-Eberhardt Arid Lands Ecology (ALE) Reserve. More recently, larger numbers of elk have been occupying the U.S. Department of Energy (DOE), Hanford Field Office (HFO), formerly the DOE, Richland Operations Office managed portion- of the Hanford Site, known as central Hanford (Figure 1-1). This began with bachelor groups of bulls occupying the site intermittently, and the herd has grown to resident herds, including bulls, cows, and calves. The Washington Department of Fish and Wildlife (WDFW) established a target herd size for the RHEH of less than 350 animals to minimize damages on adjacent private agricultural lands (Washington State Elk Herd Plan–Yakima Elk Herd [WDFW 2002]). Attempts to control the RHEH population through hunting on private lands and a relocation effort during 2000 have failed to limit growth of the population toward the WDFW target, and the herd exceeds 1,600 according to recent counts (PNNL-13331; DOE/RL- 2023-20, Hanford Annual Site Environmental Report for Calendar Year 2022). Although elk are present on central Hanford year-round, they continue to move between areas offsite, the ALE Reserve, and central Hanford throughout the year, and it is these movements that result in many of the elk-vehicle collisions (EVC) that occur along Hanford Site roads and on the Washington State highways bordering the site. In addition, changes in management strategies on the ALE Reserve, including recent and potential future tribal elk hunts, may alter herd behavior and result in additional animals transiting onto and off central Hanford.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Improved Quasi-Static Method: IQS Method Implementation for CFEM Diffusion in Rattlesnake

The improved quasi-static (IQS) method is a transient spatial kinetics method that involves factorizing flux into space- and time-dependent components. These components include the flux’s power and shape. Power is time-dependent, while the shape is both space- and time-dependent. However, the impetus of the method is the assumption that the shape is only weakly dependent on time; therefore, the shape may not require computation at every time step, invoking the quasi-static nature. This paper describes the implementation and testing of IQS as an alternative kinetics solver within Rattlesnake to provide improved time performance with minimal reduction in accuracy.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2016

Multiscale Capability in Rattlesnake using Contiguous Discontinuous Discretization of Self-Adjoint Angular Flux Equation

In this report, we present a new upwinding scheme for the multiscale capability in Rattlesnake, the MOOSE based radiation transport application. Comparing with the initial implementation of multiscale utilizing Lagrange multipliers to impose strong continuity of angular flux on interface of in-between subdomains, this scheme does not require the particular domain partitioning. This upwinding scheme introduces discontinuity of angular flux and resembles the classic upwinding technique developed for solving first order transport equation using discontinuous finite element method (DFEM) on the subdomain interfaces. Because this scheme restores the causality of radiation streaming on the interfaces, significant accuracy improvement can be observed with moderate increase of the degrees of freedom comparing with the continuous method over the entire solution domain. Hybrid SN-PN is implemented and tested with this upwinding scheme. Numerical results show that the angular smoothing required by Lagrange multiplier method is not necessary for the upwinding scheme.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2018

Rattlesnake Theory Manual

Rattlesnake is the MOOSE [1, 2] (Multiphysics Object-Oriented Simulation Environment) based application for simulating the physics of radiation transport. Radiation transport studies the motion of particles, usually neutrons, photons or electrons, etc. and their interactions with background materials [3, 4, 5, 6, 7, 8]. The fundamental quantity of interest in radiation transport is the statistically averaged radiation distribution or flux in space (dimentionality 3), time (1), direction of motion (2) and energy (or frequency) (1), forming a seven-dimensional phase space. Various reaction rates are secondary in the sense that they are computed from the primary flux and the background material properties; however, reaction rates are typically more interesting for the analyst or when coupling to other physics, e.g. heat conduction or thermo-hydraulics. Radiation transport calculations receive feedback within a multiphysics environment through temperature and density changes, which predominantly change how radiation particles interact with the background nuclei. Accurate prediction of the flux is essential to the design and operation of nuclear facilities for the purpose of safety and economics. For example in nuclear fission reactors, neutron-induced fissions and the accumulated radiative isotopes are the main heat source. Predicting whether the heat can be removed from the reactor core under all circumstances without violation of safety limits is critical to the safety of nuclear reactors.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

Rattlesnake: User Manual

The drafted user manual for Rattlesnake, the multigroup radiation transport application based on MOOSE.

97 MATHEMATICS AND COMPUTING↗