Analysis Contour Plots in RELAP/SCDAPSIM/MOD 3.4 and MOD 4.1

2018 ◽  
Author(s):  
Heriberto Sánchez-Mora ◽  
Carlos Chávez-Mercado ◽  
Chris Allison ◽  
Judith Hohorst
Keyword(s):  
Nuclear Energy ◽  
Nuclear Reactor ◽  
Severe Accident ◽  
Energy Industry ◽  
Contour Plot ◽  
Input File ◽  
Systems Software ◽  
Contour Plots ◽  
Core Components ◽  
Control Rods

RELAP/SCDAPSIM is a nuclear reactor simulator and accident analysis code that has been used in the nuclear energy industry for many years. Currently, Innovative Systems Software is developing a new tool that will show the behavior of the core components during a simulation of an accident. The addition of contour plots for the SCDAP components showing different properties: temperature, hydrogen production, etc. will allow a better understanding of core behavior during a severe accident in a nuclear reactor. The SCDAP components are fuel rods, electrically heated simulator rods, such as those used in the CORA experiments, control rods, a shroud and a BWR blade/box. This paper describes the progress in the development of the contour plot tool based on the OpenGL and FORTRAN90 libraries. The purpose of this tool is help to the user analyze the simulation of an accident and to debug an input file.

Nitrogen removal from wastewater treatment lagoons

1999 ◽  
Vol 39 (6) ◽  
pp. 191-198 ◽  
Author(s):  
Timothy J. Hurse ◽  
Michael A. Connor
Keyword(s):  
Wastewater Treatment ◽  
Nitrogen Removal ◽  
Treatment Plant ◽  
Ammonia Removal ◽  
Contour Plot ◽  
Removal Mechanism ◽  
Dissolved Oxygen Concentration ◽  
Physical Processes ◽  
Contour Plots ◽  
Removal Processes

In an attempt to gain a better understanding of ammonia and nitrogen removal processes in multi-pond wastewater treatment lagoons, an analysis was carried out of data obtained during regular monitoring of Lagoon 115E at the Western Treatment Plant in Melbourne. To do this, a contour plot approach was developed that enables the data to be displayed as a function of pond number and date. Superimposition of contour plots for different parameters enabled the dependence of ammonia and nitrogen removal rates on various lagoon characteristics to be readily assessed. The importance of nitrification as an ammonia removal mechanism was confirmed. Temperature, dissolved oxygen concentration and algal concentration all had a significant influence on whether or not sizeable nitrifier populations developed and persisted in lagoon waters. The analysis made it evident that a better understanding of microbial, chemical and physical processes in lagoons is needed before their nitrogen removal capabilities can be predicted with confidence.

Experimental Investigation on Dependence of Decontamination Factor on Aerosol Number Concentration in Pool Scrubbing Under Normal Temperature and Pressure

2018 ◽  
Author(s):  
HaoMin Sun ◽  
Shinichi Machida ◽  
Yasuteru Sibamoto ◽  
Yuria Okagaki ◽  
Taisuke Yonomoto
Keyword(s):  
High Performance ◽  
Nuclear Reactor ◽  
Experimental System ◽  
Decontamination Factor ◽  
Number Concentration ◽  
Severe Accident ◽  
Measurement Instruments ◽  
Aerosol Number Concentration ◽  
Real Phenomenon ◽  
Validation Tests

During a severe accident of a nuclear reactor, radioactive aerosols may be released from degraded nuclear fuels. Pool scrubbing is one of the efficient filters with a high aerosol removal efficiency, in other words a high decontamination factor (DF). Because of its high performance, many pool scrubbing experiments have been performed and several pool scrubbing models have been proposed. In the existing pool scrubbing experiments, an experimental condition of aerosol number concentration was seldom taken into account. It is probably because DF is assumed to be independent of aerosol number concentration, at least, in the concentration where aerosol coagulation is limited. The existing pool scrubbing models also follow this assumption. In order to verify this assumption, we performed a pool scrubbing experiment with different aerosol number concentrations under the same boundary conditions. The test section is a transparent polycarbonate pipe with an inner diameter of 0.2 m. 0.5 μm SiO2 particles were used as aerosols. As a result, DF was increasing as decreasing the aerosol number concentration. In order to ensure a reliability of this result, three validation tests were performed with meticulous care. According to the results of these validation tests, it was indicated that DF dependence on the aerosol concentration was not because of our experimental system error including measurement instruments but a real phenomenon of the pool scrubbing.

The Measurement of Light Element Segregation Using EDS and EELS

1998 ◽  
Vol 4 (S2) ◽  
pp. 772-773
Author(s):  
J.T. Busby ◽  
E.A. Kenik ◽  
G.S. Was
Keyword(s):  
Grain Boundaries ◽  
Nuclear Reactor ◽  
Reactor Core ◽  
Light Element ◽  
Free Surfaces ◽  
Spatial Redistribution ◽  
Core Components ◽  
Radiation Induced ◽  
Potential Interactions ◽  
Impurity Elements

Radiation-induced segregation (RIS) is the spatial redistribution of elements at defect sinks such as grain boundaries and free surfaces during irradiation. This phenomenon has been studied in a wide variety of alloys and has been linked to irradiation-assisted stress corrosion cracking (IASCC) of nuclear reactor core components. However, several recent studies have shown that Cr and Mo can be enriched to significant levels at grain boundaries prior to irradiation as a result of heat treatment. Segregation of this type may delay the onset of radiation-induced Cr depletion at the grain boundary, thus reducing IASCC susceptibility. Unfortunately, existing models of segregation phenomena do not correctly describe the physical processes and therefore are grossly inaccurate in predicting pre-existing segregation and subsequent redistribution during irradiation. Disagreement between existing models and measurement has been linked to potential interactions between the major alloying elements and lighter impurity elements such as S, P, and B.

scholarly journals Perspectives on a Severe Accident Consequences—10 Years after the Fukushima Accident

2021 ◽  
Vol 2 (4) ◽  
pp. 398-411
Author(s):  
Jinho Song
Keyword(s):  
Nuclear Reactor ◽  
Severe Accident ◽  
Accident Analysis ◽  
Fukushima Accident ◽  
The Public ◽  
Analysis Methodology ◽  
International Attention ◽  
Nuclear Reactor Safety ◽  
Term Monitoring

Scientific issues that draw international attention from the public and experts during the last 10 years after the Fukushima accident are discussed. An assessment of current severe accident analysis methodology, impact on the views of nuclear reactor safety, dispute on the safety of fishery products, discharge of radioactive water to the ocean, status of decommissioning, and needs for long-term monitoring of the environment are discussed.

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