scholarly journals The Local Seismoacoustic Wavefield of a Research Nuclear Reactor and Its Response to Reactor Power Level

2020 ◽  
Vol 92 (1) ◽  
pp. 378-387
Author(s):  
Omar E. Marcillo ◽  
Monica Maceira ◽  
Chengping Chai ◽  
Christine Gammans ◽  
Riley Hunley ◽  
...  
Keyword(s):  
Energy Transport ◽  
Nuclear Reactor ◽  
Power Level ◽  
National Laboratory ◽  
Reactor Power ◽  
Operational Conditions ◽  
Oak Ridge ◽  
Research Nuclear Reactor ◽  
Full Power ◽  
Power Operation

Abstract We describe the seismoacoustic wavefield recorded outdoors but inside the facility fence of the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (Tennessee). HFIR is a research nuclear reactor that generates neutrons for scattering, irradiation research, and isotope production. This reactor operates at a nominal power of 85 MW, with a full-power period between 24 and 26 days. This study uses data from a single seismoacoustic station that operated for 60 days and sampled a full operating reactor cycle, that is, full-power operation and end-of-cycle outage. The analysis presented here is based on identifying signals that characterize the steady, that is, full-power operation and end-of-cycle outage, and transitional, that is, start-up and shutdown, states of the reactor. We found that the overall seismoacoustic energy closely follows the main power cycle of the reactor and identified spectral regions excited by specific reactor operational conditions. In particular, we identified a tonal noise sequence with a fundamental frequency around 21.4 Hz and multiple harmonics that emerge as the reactor reaches 90% of nominal power in both seismic and acoustic channels. We also utilized temperature measurements from the monitoring system of the reactor to suggest links between the operation of reactor’s subsystems and seismoacoustic signals. We demonstrate that seismoacoustic monitoring of an industrial facility can identify and track some industrial processes and detect events related to operations that involve energy transport.

Auxiliary Beam Stress Improved Laser Welding for Repair of Irradiated Light Water Reactor Components

2019 ◽  
Author(s):  
Jian Chen ◽  
Jonathan Tatman ◽  
Zhili Feng ◽  
Roger Miller ◽  
Wei Tang ◽  
...  
Keyword(s):  
Laser Welding ◽  
Nuclear Power ◽  
Nuclear Reactor ◽  
National Laboratory ◽  
Department Of Energy ◽  
Light Water Reactor ◽  
Development Effort ◽  
Light Water ◽  
Water Reactor ◽  
Oak Ridge

Abstract The welding task focuses on development of advanced welding technologies for repair and maintenance of nuclear reactor structural components to safely and cost-effectively extend the service life of nuclear power reactors. This paper presents an integrated research and development effort by the Department of Energy Light Water Reactor Sustainability Program through the Oak Ridge National Laboratory (ORNL) and Electric Power Research Institute (EPRI) to develop a patent-pending technology, Auxiliary Beam Stress Improved Laser Welding Technique, that proactively manages the stresses during laser repair welding of highly irradiated reactor internals without helium induced cracking (HeIC). Finite element numerical simulations and in-situ temperature and strain experimental validation have been utilized to identify candidate welding conditions to achieve significant stress compression near the weld pool during cooling. Preliminary welding experiments were performed on irradiated stainless-steel plates (Type 304L). Post-weld characterization reveals that no macroscopic HeIC was observed.

Machining Test Specimens From Harvested Zion RPV Segments

2015 ◽  
Author(s):  
Thomas M. Rosseel ◽  
Mikhail A. Sokolov ◽  
Randy K. Nanstad
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
National Laboratory ◽  
Compact Tension ◽  
Department Of Energy ◽  
Oak Ridge ◽  
Damage Models ◽  
The Us ◽  
Machining Test

The decommissioning of the Zion Nuclear Generating Station (NGS) in Zion, Illinois, presents a special and timely opportunity for developing a better understanding of materials degradation and other issues associated with extending the lifetime of existing nuclear power plants (NPPs) beyond 60 years of service. In support of extended service and current operations of the US nuclear reactor fleet, the Oak Ridge National Laboratory (ORNL), through the Department of Energy (DOE), Light Water Reactor Sustainability (LWRS) Program, is coordinating and contracting with Zion Solutions, LLC, a subsidiary of Energy Solutions, an international nuclear services company, the selective procurement of materials, structures, components, and other items of interest from the decommissioned reactors. In this paper, we will discuss the acquisition of segments of the Zion Unit 2 Reactor Pressure Vessel (RPV), cutting these segments into blocks from the beltline and upper vertical welds and plate material and machining those blocks into mechanical (Charpy, compact tension, and tensile) test specimens and coupons for microstructural (TEM, SEM, APT, SANS and nano indention) characterization. Access to service-irradiated RPV welds and plate sections will allow through wall attenuation studies to be performed, which will be used to assess current radiation damage models [1].

scholarly journals Batch-Scale Hydrofluorination of Li27BeF4 to Support Molten Salt Reactor Development

2015 ◽  
Vol 1 (4) ◽  
Author(s):  
Brian C. Kelleher ◽  
Kieran P. Dolan ◽  
Paul Brooks ◽  
Mark H. Anderson ◽  
Kumar Sridharan
Keyword(s):  
Molten Salt ◽  
Nuclear Reactor ◽  
National Laboratory ◽  
The United States ◽  
Hydraulic Testing ◽  
Molten Salt Reactor ◽  
Fluoride Salt ◽  
Oak Ridge ◽  
University Of Wisconsin ◽  
Analysis Process

Li 2 BeF 4 , or flibe, is the primary candidate coolant for the fluoride-salt-cooled high-temperature nuclear reactor (FHR). Kilogram quantities of pure flibe are required for repeatable corrosion tests of modern reactor materials. This paper details fluoride salt purification by the hydrofluorination–hydrogen process, which was used to regenerate 57.4 kg of flibe originating from the secondary loop of the molten salt reactor experiment (MSRE) at Oak Ridge National Laboratory (ORNL). Additionally, it expounds upon necessary handling precautions required to produce high-quality flibe and includes technological advancements which ease the purification and analysis process. Flibe batches produced at the University of Wisconsin are the largest since the MSRE program, enabling new corrosion, radiation, and thermal hydraulic testing around the United States.

Gamma Ray-Induced Embritilement of Pressure Vessel Alloys

1994 ◽  
Vol 373 ◽  
Author(s):  
Dale E. Alexander ◽  
K. Farrell ◽  
R. E. Stoller ◽  
L. E. Rehn
Keyword(s):  
Gamma Rays ◽  
Pressure Vessel ◽  
Nuclear Reactor ◽  
Gamma Ray ◽  
National Laboratory ◽  
High Energy ◽  
Displacement Damage ◽  
Oak Ridge ◽  
Energy Gamma ◽  
Property Changes

AbstractHigh-energy gamma rays emitted from the core of a nuclear reactor produce displacement damage in the reactor pressure vessel (RPV). The contribution of gamma damage to RPV embrittlement has in the past been discounted. However, in certain reactor designs the gamma flux at the RPV is sufficiently large that its contribution to displacement damage can be substantial. For example, gamma rays have been implicated in the RPV embrittlement observed in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory.In the present study, mechanical property changes induced by 10-MeV electron irradiation of a model Fe alloy and an RPV alloy of interest to the HFIR were examined. Tensile specimens were irradiated with high-energy electrons to reproduce damage characteristic of the Compton recoil-electrons induced by gamma bombardment. Substantial increases in yield and ultimate stress were observed in the alloys after irradiation to doses up to 5.3x10−3 dpa at temperatures (~50°C) characteristic of the HFIR pressure vessel. These measured increases were similar to those previously obtained following neutron irradiation, despite the highly disparate nature of the damage generated during electron and neutron irradiations.

Structural Changes in Concrete under the Influence of Reactor Spectrum Neutrons

2021 ◽  
Vol 1037 ◽  
pp. 663-668
Author(s):  
Maria A. Frolova ◽  
Sergey D. Strekalov ◽  
Sergey S. Bezotosny ◽  
Pavel A. Ponomarenko
Keyword(s):  
Structural Changes ◽  
Nuclear Reactor ◽  
Operating Conditions ◽  
Energy Output ◽  
Concrete Composition ◽  
Neutron Flux Density ◽  
Reactor Spectrum ◽  
Research Nuclear Reactor ◽  
Power Operation ◽  
Concrete Component

The paper considers structural changes in the concrete composition that occur under the influence of neutrons of the reactor spectrum, using the example of the IR-100 research nuclear reactor, taking into account its real time and operating conditions. Thus, taking into account the energy output, power operation modes, and neutron flux density in the core, over time, nuclides that are not characteristic of the original composition of the concrete component are formed in the nodes of the crystal lattice. However, these changes do not lead to significant structural changes.

Neural Network with Local Memory for Nuclear Reactor Power Level Control

2001 ◽  
Vol 133 (2) ◽  
pp. 213-228 ◽  
Author(s):  
Önder Uluyol ◽  
Magdi Ragheb ◽  
Lefteri Tsoukalas
Keyword(s):  
Neural Network ◽  
Nuclear Reactor ◽  
Power Level ◽  
Reactor Power ◽  
Level Control ◽  
Local Memory

Seismically Detecting Nuclear Reactor Operations Using a Power Spectral Density (PSD) Misfit Detector

2021 ◽  
Author(s):  
David L. Guenaga ◽  
Chengping Chai ◽  
Monica Maceira ◽  
Omar E. Marcillo ◽  
Aaron A. Velasco
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Nuclear Reactor ◽  
National Laboratory ◽  
Waveform Data ◽  
Oak Ridge ◽  
Power Spectral ◽  
And Performance ◽  
Additional Station ◽  
Initial Results

ABSTRACT To explore the ability to indirectly detect and attribute various operations conducted at a nuclear reactor using waveform data, we investigated the seismic signals recorded near the High Flux Isotope Reactor (HFIR) located at Oak Ridge National Laboratory in Oak Ridge, Tennessee. Specifically, we processed seismic data collected from a single seismoacoustic station, WACO, near the HFIR facility, and employed a power spectral density misfit detector to identify signals of interest and associate the detections with operational events. Initial results suggest that this method provides a promising means of regularly detecting at least 19 unique operations. With additional station deployment and more comprehensive data logs, we anticipate that future analysis will offer an additional means to seismically monitor nuclear reactors (such as HFIR) health and performance more accurately.

Sign in / Sign up

Export Citation Format

Share Document