scholarly journals Nuclear Facility Safety Enhancement Using Sandia National Laboratories’ Computer Codes

2018 ◽  
Author(s):  
David L. Y. Louie
Keyword(s):  
Solid Mechanics ◽  
Source Term ◽  
Nuclear Regulatory Commission ◽  
Department Of Energy ◽  
Nuclear Facility ◽  
Nuclear Facilities ◽  
Safety Research ◽  
Central Registry ◽  
Computer Codes ◽  
Safety Enhancement

This paper describes the ongoing study of nuclear facility safety enhancement using Sandia National Laboratories’ (SNL) computer codes, supported by U.S. Department of Energy (DOE) Nuclear Safety Research and Development (NSR&D) Program. Continued DOE NSR&D support, since 2014 has allowed the use of the SNL engineering code suite (SIERRA Mechanics) to further substantiate data in the DOE Handbook published in 1994: DOE-HDBK-3010-94, “Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear Facilities.” The use of SIERRA codes allows for a better understanding of the mechanics, dynamics, chemistry and overall physics of airborne release scenarios. SIERRA codes provide insights into the contributing phenomena of source term releases from events such as liquid fires. The 1994 Handbook documents small-scaled, bench-top and limited experiments involving liquid fires, powder spills, pressurized releases, and mechanical insult-induced fragmentation scenarios. Data recorded from these scenarios has been substantiated using SIERRA solid mechanics and fluid mechanics codes. Data passing among multi-physics SIERRA codes predicted the contaminant release from a drum rupture due to fire even though there is no experimental data available. In the anticipated revision effort of the Handbook by DOE, these computational capabilities could enhance the data in a broader usage and could provide confidence in the safety analysis SIERRA codes can provide the initial source term to be used in the leak path factor (LPF) analyses, which predicts the ST release out of the facility. Typical LPF analysis is done using the MELCOR code, developed at SNL for the U.S. Nuclear Regulatory Commission. Widely used in nuclear reactor applications, MELCOR is a toolbox safety code in the DOE’s central registry for LPF applications. A recent LPF guidance study done by SNL indicated that MELCOR 2.1, along with updated guidance, should replace the obsolete MELCOR 1.8.5 guidance. This new guidance is significantly improved over the previous guidance, utilizing extensive MELCOR validation, including applicable reactor experiments and experiments described in the DOE-HDBK-3010-94 for LPF applications. The latest version of MELCOR should be included in DOE’s central registry, and should be used by safety analysts for LPF analyses.

scholarly journals Nuclear Facility Safety at the United States Department of Energy

2020 ◽  
Author(s):  
Patrick Frias ◽  
José R. O. Muñoz ◽  
Louis Restrepo ◽  
James L. Tingey ◽  
David L. Y. Louie
Keyword(s):  
United States ◽  
The United States ◽  
Nuclear Safety ◽  
Lessons Learned ◽  
Department Of Energy ◽  
United States Department ◽  
Nuclear Facility ◽  
Near Misses ◽  
States Department ◽  
Safety Research

Abstract Nuclear facility safety is crucial to preventing and/or reducing high consequence-low probability accidents and, thus reducing the potential risks posed by United States Department of Energy (DOE) and National Nuclear Security Administration (NNSA) operations at their facilities/activities. DOE/NNSA has the responsibility of developing, issuing, maintaining, and enforcing nuclear safety Directives while fostering a culture that promotes nuclear safety research and development. Lessons learned from past accidents, near misses, and experiments/analyses are also important resources for improving operational nuclear safety in the safety community. This paper first identifies and describes the current Directives in place, including safety review and regulatory process, and safety programs that support implementation of the Directives. This paper also describes a contractor’s approach to identifying and implementing safety using these Directives and lessons-learned in multiple discipline areas of nuclear safety.

Codes, Standards and Regulatory Topics for Nuclear Facilities

2008 ◽  
Author(s):  
Taunia Wilde ◽  
Shannan Baker ◽  
Gary M. Sandquist
Keyword(s):  
Quality Control ◽  
Quality Assurance ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Regulatory Commission ◽  
Department Of Energy ◽  
Quality Assurance Program ◽  
Nuclear Facilities ◽  
The Us ◽  
Regulatory Commission

The design, construction, operation, maintenance, and decommissioning and decontamination of nuclear infrastructure particularly nuclear power plants licensed in the US by the US Nuclear Regulatory Commission (NRC) or operated by the US Department of Energy (DOE) or the US Department of Defense (DOD) must be executed under a rigorous and documented quality assurance program that provides adequate quality control and oversight. Those codes, standards, and orders regulate, document and prescribe the essentials for quality assurance (QA) and quality control (QC) that frequently impact nuclear facilities operated in the US are reviewed and compared.

Numerical Simulation of Container Breach and Airborne Release of Solids Due to Mechanical Insults

2021 ◽  
Vol 7 (3) ◽  
Author(s):  
David L. Y. Louie ◽  
San Le ◽  
Lindsay N. Gilkey
Keyword(s):  
Solid Mechanics ◽  
Source Term ◽  
Free Fall ◽  
Department Of Energy ◽  
High Fidelity ◽  
Computational Tools ◽  
Respirable Fraction ◽  
Waste Container ◽  
Model Predictions ◽  
Accident Conditions

Abstract Throughout U.S. Department of Energy (DOE) complexes, safety engineers employ the five-factor formula to calculate the source term (ST) that includes parameters of airborne release fraction (ARF), respirable fraction (RF) and damage ratio (DR). Limited experimental data on fragmentation of solids, such as ceramic pellets (i.e., PuO2), and container breach due to mechanical insults (i.e., drop and forklift impact), can be supplemented by modeling and simulation using high fidelity computational tools to estimate these parameters. This paper presents the use of Sandia National Laboratories' SIERRA solid mechanics (SM) finite element code to investigate the behavior of the widely utilized waste container (such as 7A Drum) subject to a range of free fall impact and puncture scenarios. The resulting behavior of the container is assessed, and the estimates are presented for bounding DRs from calculated breach areas for the various accident conditions considered. This paper also describes a novel multiscale constitutive model recently implemented in SIERRA/SM that simulates the fracture of brittle materials such as PuO2 and determines ARF during the fracture process. Comparisons are made between model predictions and simple bench-top experiments.

Regulatory experience in applying a radiological environmental protection framework for existing and planned nuclear facilities

2012 ◽  
Vol 41 (3-4) ◽  
pp. 256-262 ◽  
Author(s):  
S. Mihok ◽  
P. Thompson
Keyword(s):  
Environmental Protection ◽  
Environmental Protection Agency ◽  
Nuclear Regulatory Commission ◽  
Nuclear Safety ◽  
Department Of Energy ◽  
Dose Assessment ◽  
Radiological Protection ◽  
Nuclear Facilities ◽  
Legal Requirements ◽  
Energy Agency

Frameworks and methods for the radiological protection of non-human biota have been evolving rapidly at the International Commission on Radiological Protection and through various European initiatives. The International Atomic Energy Agency has incorporated a requirement for environmental protection in the latest revision of its Basic Safety Standards. In Canada, the Canadian Nuclear Safety Commission has been legally obligated to prevent unreasonable risk to the environment since 2000. Licensees have therefore been meeting generic legal requirements to demonstrate adequate control of releases of radioactive substances for the protection of both people and biota for many years. In the USA, in addition to the generic requirements of the Environmental Protection Agency and the Nuclear Regulatory Commission, Department of Energy facilities have also had to comply with specific dose limits after a standard assessment methodology was finalised in 2002. Canadian regulators developed a similar framework for biota dose assessment through a regulatory assessment under the Canadian Environmental Protection Act in the late 1990s. Since then, this framework has been applied extensively to satisfy legal requirements under the Canadian Environmental Assessment Act and the Nuclear Safety and Control Act. After approximately a decade of experience in applying these methods, it is clear that simple methods are fit for purpose, and can be used for making regulatory decisions for existing and planned nuclear facilities.

Site Decommissioning of AECL Whiteshell Laboratories

2004 ◽  
Vol 824 ◽  
Author(s):  
Grant W. Koroll
Keyword(s):  
Waste Management ◽  
Environmental Assessment ◽  
Materials Science ◽  
Nuclear Research ◽  
Management Program ◽  
Nuclear Facilities ◽  
Safety Research ◽  
Nuclear Installation ◽  
Underground Research Laboratory ◽  
Nuclear Fuel Waste

AbstractAECL Whiteshell Laboratories (WL), near Winnipeg, Canada has been in operation since the early 1960s. R&D programs carried out at WL include a 60 MW organic-cooled research reactor, which operated from 1965 to 1985, reactor safety research, small reactor development, materials science, post irradiation examinations, chemistry, biophysics and radiation applications. The Canadian Nuclear Fuel Waste Management Program was conducted and continues to operate at WL and also at the nearby Underground Research Laboratory.In the late-1990s, AECL began to consolidate research and development activities at its Chalk River Laboratories (CRL) and began preparations for decommissioning WL. Preparations for decommissioning included a staged shutdown of operations, planning documentation and licensing for decommissioning. As a prerequisite to AECL's application for a decommissioning licence, an environmental assessment (EA) was carried out according to Canadian environmental assessment legislation. The EA concluded in 2002 April when the Federal Environment Minister published his decision that WL decommissioning was not likely to cause significant adverse environmental effects and that no further assessment by a review panel or mediation would be requiredIn 2002 December, the Canadian Nuclear Safety Commission issued a decommissioning licence for WL, valid until December 31, 2008. The licence authorized the first planned phase of site decommissioning as well as the continuation of selected research programs. The six-year licence for Whiteshell Laboratories was the first overall decommissioning license issued for a Canadian Nuclear Research and Test Establishment and was the longest licence term ever granted for a nuclear installation of this complexity in Canada.The first phase of decommissioning is now underway and focuses on decontamination and modifications to nuclear facilities, such as the shielded facilities, the main R&D laboratories and the associated service systems, to achieve a safe state of storage-with-surveillance. Later phases have planned waste management improvements for selected wastes already in storage, eventually followed by final decommissioning of facilities and infrastructure and removal of most wastes from the site.This paper provides an overview of the planning, environmental assessment, licensing, and organizational processes for decommissioning and selected descriptions of decommissioning activities currently underway at AECL Whiteshell Laboratories.

Development of Testing Methodologies for Onsite Radioactive Material Storage Containers

2008 ◽  
Author(s):  
Matthew R. Feldman
Keyword(s):  
Lawrence Livermore National Laboratory ◽  
National Laboratory ◽  
Nuclear Material ◽  
Department Of Energy ◽  
Radioactive Material ◽  
Development Effort ◽  
Nuclear Facilities ◽  
Los Alamos National Laboratory ◽  
Oak Ridge ◽  
Transportation Technologies

Based on a recommendation from the Defense Nuclear Facilities Safety Board, the Department of Energy (DOE) Office of Nuclear Safety Policy and Assistance (HS-21) has recently issued DOE Manual 441.1-1 entitled Nuclear Material Packaging Manual. This manual provides guidance regarding the use of non-engineered storage media for all special nuclear material throughout the DOE complex. As part of this development effort, HS-21 has funded the Oak Ridge National Laboratory (ORNL) Transportation Technologies Group (TTG) to develop and demonstrate testing protocols for such onsite containers. ORNL TTG to date has performed preliminary tests of representative onsite containers from Lawrence Livermore National Laboratory and Los Alamos National Laboratory. This paper will describe the testing processes that have been developed.

scholarly journals Remote Monitoring and Evaluation of Damage at a Decommissioned Nuclear Facility Using Acoustic Emission

2018 ◽  
Vol 8 (9) ◽  
pp. 1663 ◽  
Author(s):  
Marwa Abdelrahman ◽  
Mohamed ElBatanouny ◽  
Kenneth Dixon ◽  
Michael Serrato ◽  
Paul Ziehl
Keyword(s):  
Acoustic Emission ◽  
Remote Monitoring ◽  
Nuclear Reactor ◽  
Corrosion Damage ◽  
Monitoring And Evaluation ◽  
Structural Condition ◽  
Spent Fuel ◽  
Nuclear Facility ◽  
Nuclear Facilities ◽  
Accelerated Corrosion

Reinforced concrete systems used in the construction of nuclear reactor buildings, spent fuel pools, and related nuclear facilities are subject to degradation over time. Corrosion of steel reinforcement and thermal cracking are potential degradation mechanisms that adversely affect durability. Remote monitoring of such degradation can be used to enable informed decision making for facility maintenance operations and projecting remaining service life. Acoustic emission (AE) monitoring has been successfully employed for the detection and evaluation of damage related to cracking and material degradation in laboratory settings. This paper describes the use of AE sensing systems for remote monitoring of active corrosion regions in a decommissioned reactor facility for a period of approximately one year. In parallel, a representative block was cut from a wall at a similar nuclear facility and monitored during an accelerated corrosion test in the laboratory. Electrochemical measurements were recorded periodically during the test to correlate AE activity to quantifiable corrosion measurements. The results of both investigations demonstrate the feasibility of using AE for corrosion damage detection and classification as well as its potential as a remote monitoring technique for structural condition assessment and prognosis of aging structures.

scholarly journals Analysis of Powder Airborne Release Fractions for Vessel Ruptures

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
James E. Laurinat ◽  
Steve J. Hensel
Keyword(s):  
Fluidized Bed ◽  
Pacific Northwest ◽  
Three Dimensional ◽  
Initial Pressure ◽  
Department Of Energy ◽  
Nuclear Facilities ◽  
Powder Bed ◽  
Pacific Northwest Laboratory ◽  
Vessel Volume ◽  
Low Pressures

The Department of Energy (DOE) handbook for airborne releases from nonreactor nuclear facilities bases its bounding airborne release fraction (ARF) for pressurized powders on tests conducted at Pacific Northwest Laboratory (PNL). An analysis is presented that correlates the ARF from these tests. The amount of powder that becomes airborne is correlated in terms of an adjusted airborne release fraction (AARF) equal to the product of the powder entrainment from the powder bed and the ratio of the total vessel volume to the volume occupied by the powder bed. Powder entrainments and release fractions at low pressures are correlated using a fluidized bed analogy. The analysis shows that the entrainment is enhanced by a sonic shock if the pressure prior to the rupture exceeds approximately 0.329 MPa (33 psig). A secondary, three-dimensional shock is predicted to occur at an initial pressure of approximately 2.39 MPa (332 psig). A correlation based on this analysis is used to predict the ARF for ruptures of vessels containing plutonium oxide. It is assumed that the oxide is pressurized by hydrogen that is radiolytically generated from adsorbed moisture.

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