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Fukushima Daiichi Unit 1 Uncertainty Analysis-Exploration of Core Melt Progression Uncertain Parameters-Volume II

Denman, Matthew R.; Brooks, Dusty M.

Sandia National Laboratories (SNL) has conducted an uncertainty analysis (UA) on the Fukushima Daiichi unit (1F1) accident progression with the MELCOR code. Volume I of the 1F1 UA discusses the physical modeling details and time history results of the UA. Volume II of the 1F1 UA discusses the statistical viewpoint. The model used was developed for a previous accident reconstruction investigation jointly sponsored by the US Department of Energy (DOE) and Nuclear Regulatory Commission (NRC). The goal of this work was to perform a focused evaluation of uncertainty in core damage progression behavior and its effect on key figures-ofmerit (e.g., hydrogen production, fraction of intact fuel, vessel lower head failure) and in doing so assess the applicability of traditional sensitivity analysis techniques.

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TYPE SAND Report YEAR 2015
DOIOSTI

NetMOD Version 2.0 Mathematical Framework

Merchant, Bion J.

NetMOD (Network Monitoring for Optimal Detection) is a Java-based software package for conducting simulation of seismic, hydroacoustic and infrasonic networks. Network simulations have long been used to study network resilience to station outages and to determine where additional stations are needed to reduce monitoring thresholds. NetMOD makes use of geophysical models to determine the source characteristics, signal attenuation along the path between the source and station, and the performance and noise properties of the station. These geophysical models are combined to simulate the relative amplitudes of signal and noise that are observed at each of the stations. From these signal-to-noise ratios (SNR), the probabilities of signal detection at each station and event detection across the network of stations can be computed given a detection threshold. The purpose of this document is to clearly and comprehensively present the mathematical framework used by NetMOD, the software package developed by Sandia National Laboratories to assess the monitoring capability of ground-based sensor networks. Many of the NetMOD equations used for simulations are inherited from the NetSim network capability assessment package developed in the late 1980s by SAIC (Sereno et al., 1990).

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TYPE SAND Report YEAR 2015
DOIOSTI

NetMOD Version 2.0 Parameters

Merchant, Bion J.

NetMOD (Network Monitoring for Optimal Detection) is a Java-based software package for conducting simulation of seismic, hydroacoustic and infrasonic networks. Network simulations have long been used to study network resilience to station outages and to determine where additional stations are needed to reduce monitoring thresholds. NetMOD makes use of geophysical models to determine the source characteristics, signal attenuation along the path between the source and station, and the performance and noise properties of the station. These geophysical models are combined to simulate the relative amplitudes of signal and noise that are observed at each of the stations. From these signal-to-noise ratios (SNR), the probability of detection can be computed given a detection threshold. This document describes the parameters that are used to configure the NetMOD tool and the input and output parameters that make up the simulation definitions.

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TYPE SAND Report YEAR 2015
DOIOSTI

MELCOR Computer Code Manuals Volume 1: Primer and Users' Guide

Humphries, Larry L.; Figueroa Faria, Victor G.; Young, Michael F.; Foulk, James W.; Reynolds, John

MELCOR is a fully integrated, engineering-level computer code that models the progression of severe accidents in light water reactor nuclear power plants. MELCOR is being developed at Sandia National Laboratories for the U.S. Nuclear Regulatory Commission as a second-generation plant risk assessment tool and the successor to the Source Term Code Package. A broad spectrum of severe accident phenomena in both boiling and pressurized water reactors is treated in MELCOR in a unified framework. These include thermal-hydraulic response in the reactor coolant system, reactor cavity, containment, and confinement buildings; core heatup, degradation, and relocation; core-concrete attack; hydrogen production, transport, and combustion; fission product release and transport behavior. Current uses of MELCOR include estimation of severe accident source terms and their sensitivities and uncertainties in a variety of applications.

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TYPE Other Report YEAR 2015
DOIOSTI

MELCOR Computer Code Manuals

Humphries, Larry L.; Figueroa Faria, Victor G.; Young, Michael F.; Foulk, James W.; Reynolds, John

MELCOR is a fully integrated, engineering-level computer code that models the progression of severe accidents in light water reactor nuclear power plants. MELCOR is being developed at Sandia National Laboratories for the U.S. Nuclear Regulatory Commission as a second-generation plant risk assessment tool and the successor to the Source Term Code Package. A broad spectrum of severe accident phenomena in both boiling and pressurized water reactors is treated in MELCOR in a unified framework. These include thermal-hydraulic response in the reactor coolant system, reactor cavity, containment, and confinement buildings; core heatup, degradation, and relocation; core-concrete attack; hydrogen production, transport, and combustion; fission product release and transport behavior. Current uses of MELCOR include estimation of severe accident source terms and their sensitivities and uncertainties in a variety of applications.

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TYPE Other Report YEAR 2015
DOIOSTI

Can symmetry transitions of complex fields enable 3-d control of fluid vorticity?

Martin, James E.; Solis, Kyle J.

Methods of inducing vigorous noncontact fluid flow are important to technologies involving heat and mass transfer and fluid mixing, since they eliminate the need for moving parts, pipes and seals, all of which compromise system reliability. Unfortunately, traditional noncontact flow methods are few, and have limitations of their own. We have discovered two classes of fields that can induce fluid vorticity without requiring either gravity or a thermal gradient. The first class we call Symmetry-Breaking Rational Fields. These are triaxial fields comprised of three orthogonal components, two ac and one dc. The second class is Rational Triad Fields, which differ in that all three components are alternating. In this report we quantify the induced vorticity for a wide variety of fields and consider symmetry transitions between these field types. These transitions give rise to orbiting vorticity vectors, a technology for non-contact, non-stationary fluid mixing.

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TYPE SAND Report YEAR 2015
DOIOSTI

Photovoltaic System Modeling: Uncertainty and Sensitivity Analyses

Hansen, Clifford; Martin, Curtis E.

We report an uncertainty and sensitivity analysis for modeling AC energy from photovoltaic systems. Output from a PV system is predicted by a sequence of models. We quantify uncertainty in the output of each model using empirical distributions of each model’s residuals. We propagate uncertainty through the sequence of models by sampling these distributions to obtain an empirical distribution of a PV system’s output. We consider models that: (1) translate measured global horizontal, direct and global diffuse irradiance to plane-of-array irradiance; (2) estimate effective irradiance; (3) predict cell temperature; (4) estimate DC voltage, current and power; (5) reduce DC power for losses due to inefficient maximum power point tracking or mismatch among modules; and (6) convert DC to AC power. Our analysis considers a notional PV system comprising an array of FirstSolar FS-387 modules and a 250 kW AC inverter; we use measured irradiance and weather at Albuquerque, NM. We found the uncertainty in PV system output to be relatively small, on the order of 1% for daily energy. We found that uncertainty in the models for POA irradiance and effective irradiance to be the dominant contributors to uncertainty in predicted daily energy. Our analysis indicates that efforts to reduce the uncertainty in PV system output predictions may yield the greatest improvements by focusing on the POA and effective irradiance models.

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TYPE SAND Report YEAR 2015
DOIOSTI

Selecting RMF Controls for National Security Systems

Witzke, Edward L.

In 2014, the United States Department of Defense started transitioning the way it performs risk management and accreditation of information systems to a process entitled Risk Management Framework for DoD Information Technology or RMF for DoD IT. There are many more security and privacy controls (and control enhancements) from which to select in RMF, than there were in the previous Information Assurance process. This report is an attempt to clarify the way security controls and enhancements are selected. After a brief overview and comparison of RMF for DoD IT with the previously used process, this report looks at the determination of systems as National Security Systems (NSS). Once deemed to be an NSS, this report addresses the categorization of the information system with respect to impact levels of the various security objectives and the selection of an initial baseline of controls. Next, the report describes tailoring the controls through the use of overlays and scoping considerations. Finally, the report discusses organization-defined values for tuning the security controls to the needs of the information system.

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TYPE SAND Report YEAR 2015
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Results 46601–46700 of 99,299
Results 46601–46700 of 99,299