scholarly journals Logistical Simulation Modeling for Planning a Soil Remediation Process

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
David Kessel ◽  
Jihan Jeon ◽  
Jaeyeon Jung ◽  
Eutteum Oh ◽  
Chang-Lak Kim
Keyword(s):  
Simulation Model ◽  
Soil Remediation ◽  
Nuclear Power ◽  
Power Plants ◽  
Discrete Event ◽  
Soil Washing ◽  
Batch Process ◽  
Washing Process ◽  
Plant Operations ◽  
Remediation Process

This paper describes the development of a discrete event simulation model using the FlexSim software to support planning for soil remediation at Korean nuclear power plants that are undergoing decommissioning. Soil remediation may be required if site characterization shows that there has been radioactive contamination of soil from plant operations or the decommissioning process. The simulation model was developed using a dry soil separation and soil washing process. Preliminary soil data from the Kori 1 nuclear power plant was used in the model. It was shown that a batch process such as soil washing can be effectively modeled as a discrete event process. Efficient allocation of resources and efficient waste management including volume and classification reduction can be achieved by use of the model for planning the soil remediation process. Cost will be an important criterion in the choice of suitable technologies for soil remediation but is not included in this conceptual model.

scholarly journals Removal of Radioactive Cesium in Secondary Wastewater after Soil-washing Process

2020 ◽  
Vol 42 (8) ◽  
pp. 405-413
Author(s):  
Juhyeok Lee ◽  
Jaeeun Kang ◽  
Won-Seok Kim
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Soil Washing ◽  
Neutral Condition ◽  
Adsorption Rate ◽  
Radioactive Cesium ◽  
Desorption Rate ◽  
Washing Process ◽  
Before And After ◽  
Neutral Conditions

Objectives : Secondary wastewater is generated as the soil washing process proceeds to restore contaminated soil near the nuclear power plants (NPPs). In this study, we tried to evaluate the possibility of removing radioactive cesium from secondary wastewater through the adsorption process using illite.Methods : To treat radioactive cesium present in wastewater, as an adsorbent, we used illite collected from Yeongdong, Chungbuk, and weathering illite artificially weathered by high temperature and acid treatment (60℃, 0.01 M HCl). Before and after weathering, the adsorption rate of illite at low concentrations of cesium and the desorption rate of adsorbents were compared and evaluated using a 1.5 ppm of competitive potassium ion similar to that of groundwater.Results and Discussion : When the illite was artificially weathered, the amount of frayed edge sites increased as the interlayer ions in the illite eluted. As a result of the adsorption and desorption experiments, it was confirmed that the adsorption rate of weathering illite increased by about 11% in acid condition (pH 3) and about 26% in neutral condition (pH 6.2), and the desorption rate of weathering illite decreased by about 6% in acid and neutral conditions, compared to Yeongdong illite. Yeongdong illite and weathering illite showed higher adsorption rate under neutral condition than acidic condition, because the surface of the illite became negatively charged at high pH so the reactivity with cesium present as a cation increased.Conclusions : The artificial weathering process has improved the performance of illite as an adsorbent. We expect that weathering illite can be used as an effective adsorbent for the removal of radioactive cesium from NPP.

scholarly journals Stochastic Optimization for Long Term Capital Structures, Systems, and Components Refurbishment and Replacement

2020 ◽  
Author(s):  
Congjian Wang ◽  
Diego Mandelli ◽  
Shawn St Germain ◽  
Curtis Smith ◽  
David Morton ◽  
...  
Keyword(s):  
Stochastic Optimization ◽  
Nuclear Power ◽  
Power Plants ◽  
Capital Investments ◽  
Priority List ◽  
Multi Stage ◽  
Plant Operations ◽  
Economic Constraints ◽  
Returns On Investment

Abstract As commercial nuclear power plants (NPPs) pursue extended plant operations in the form of Second License Renewals (SLRs), opportunities exist for these plants to provide capital investments to ensure long-term, safe, and economic performance. Several utilities have already announced their intention to pursue extended operations for one or more of their NPPs via SLR2. The goal of this research is to develop a risk-informed approach to evaluate and prioritize plant capital investments made in preparation for, and during the period of, extended plant operations to support decisions in NPP operations. In order to prioritize project selection via a risk-informed approach we developed a single decision-making tool that integrates safety/reliability, cost, and stochastic optimization models to provide users with data analysis capabilities to more cost effectively manage plant assets. Both stochastic analysis methods — such as Monte Carlo-based sampling strategies — and multi-stage stochastic optimization strategies are employed to provide priority lists to decision-makers in support of risk-informed decisions. We applied the proposed method to a trial application of projected replacement/refurbishment expenditures for plant capital assets (i.e., structures, systems, and components [SSCs]). The objective is to optimize the SSC replacement/refurbishment schedule in terms of economic constraints, data uncertainties, and SSC reliability data, as well to generate a priority list for maximizing returns on investment.

Design and Development of Virtual DCS Debugging and Research Platform Based on NPP Simulation Model

2018 ◽  
Author(s):  
Caike Zhang ◽  
Jingwen Qi ◽  
Chun Liu ◽  
Chenglong Xie ◽  
Peibang Liu ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Simulation Model ◽  
Nuclear Power ◽  
Power Plants ◽  
Professional Training ◽  
Nuclear Power Plants ◽  
Testing Procedures ◽  
Communication Program ◽  
Research Platform

At present, DCS is widely used as the control system for nuclear power plants both at home and abroad, which prompting many companies to research the technology of DCS debugging. In this paper, taking a certain nuclear power plant within China for reference, the virtual DCS debugging and research platform which based on the full-scope nuclear power plant simulation model is developed. It was developed by first establishing a simulation model on the RINSIM Simulation Platform and ordering a customized set of virtual DCS system, then developing a communication program between the simulation model and the virtual DCS system. Users can observe the actual effects and results if following the pre-designed testing procedures after the configuration of control logics, HMI (Human Machine Interface) and I/O communication interfaces. The virtual DCS platform is aimed at assisting with technology research of DCS project for similar nuclear power plants and also can provide professional training for associated personnel of nuclear power plant.

scholarly journals Coupling of Anodic Oxidation and Soil Remediation Processes: A Review

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4309 ◽  
Author(s):  
Maiara Barbosa Ferreira ◽  
Aline Maria Sales Solano ◽  
Elisama Vieira dos Santos ◽  
Carlos A. Martínez-Huitle ◽  
Soliu O. Ganiyu
Keyword(s):  
Anodic Oxidation ◽  
Soil Remediation ◽  
Contaminated Soils ◽  
Soil Washing ◽  
Ex Situ ◽  
Combined Processes ◽  
Environmental Consequences ◽  
Efficient Coupling ◽  
Remediation Process

In recent years, due to industrial modernization and agricultural mechanization, several environmental consequences have been observed, which make sustainable development difficult. Soil, as an important component of ecosystem and a key resource for the survival of human and animals, has been under constant contamination from different human activities. Contaminated soils and sites require remediation not only because of the hazardous threat it possess to the environment but also due to the shortage of fresh land for both agriculture and urbanization. Combined or coupled remediation technologies are one of the efficient processes for the treatment of contaminated soils. In these technologies, two or more soil remediation techniques are applied simultaneously or sequentially, in which one technique complements the other, making the treatment very efficient. Coupling anodic oxidation (AO) and soil remediation for the treatment of soil contaminated with organics has been studied via two configurations: (i) soil remediation, ex situ AO, where AO is used as a post-treatment stage for the treatment of effluents from soil remediation process and (ii) soil remediation, in situ AO, where both processes are applied simultaneously. The former is the most widely investigated configuration of the combined processes, while the latter is less common due to the greater diffusion dependency of AO as an electrode process. In this review, the concept of soil washing (SW)/soil flushing (SF) and electrokinetic as soil remediation techniques are briefly explained followed by a discussion of different configurations of combined AO and soil remediation.

scholarly journals In-Plant Logistics Simulation Model for the Catering Service Industry Towards Sustainable Development: A Case Study

2019 ◽  
Vol 11 (13) ◽  
pp. 3655 ◽  
Author(s):  
Carman K.M. Lee ◽  
Shuzhu Zhang ◽  
Kam K.H. Ng
Keyword(s):  
Simulation Model ◽  
Labor Force ◽  
Service Industry ◽  
Discrete Event ◽  
Labor Cost ◽  
Utilization Rate ◽  
Event Simulation ◽  
Washing Process ◽  
One Stop

An increasing number of people are conscious of the environmental awareness in various industries, particularly in city areas. It is now a popular trend for the urban catering service industry to outsource its labor-intensive activities, such as dishwashing, to a central dishwashing facility, in which labor force management and optimization are essential. Moreover, the increasing labor cost and fluctuating labor supply drive the increasing need for labor force optimization. This research develops an in-plant logistics simulation model for a central dishwashing facility with the purpose of improving its labor force utilization rate. A discrete event simulation model is established to simulate the tableware washing process, and this model is employed in a one-stop environmentally hygienic dishwashing service provider for trial implementation. The simulation result has been compared with actual situations, identifies the main bottlenecks of the tableware washing process, optimizes the utilization rate of the labor force, and further helps to improve the productivity.

Design and Baseline Testing of Motor Operated Valves (MOVs) for Generation 3+ Nuclear Power Generating Plants

2012 ◽  
Author(s):  
Matthew E. Hobbs ◽  
Richard J. Gradle ◽  
Floyd A. Bensinger
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Lessons Learned ◽  
Baseline Data ◽  
Design Parameters ◽  
Production Testing ◽  
Class 1 ◽  
Plant Operations ◽  
Thrust And Torque

Flowserve is supplying motor operated valves (MOVs) to Generation 3+ nuclear power plants. These valves have been custom designed to meet the design and qualification criteria for ASME Section III, Class 1 nuclear service. To support plant operations, the valve designs benefit from the lessons learned from US NRC Generic Letter 89-10, “Safety-Related Motor-Operated Valve Testing and Surveillance”, the subsequent MOV testing programs, the Joint Owners Group (JOG) MOV Periodic Verification Program and ASME QME-1 functional qualifications. As a result, some new MOV designs are larger and heavier than typical valves of corresponding size and pressure class supplied to existing nuclear power plants. During the valve functional testing portion of valve manufacturer’s production testing, each MOV assembly is instrumented to record stem thrust and torque, position, motor operator voltage and current draw, and limit switch and torque switch function. The data are digitally recorded for further review and acceptance. The baseline data will allow the end user to confirm proper MOV installation and setup. The baseline data can also be compared to future in-situ test data to evaluate potential performance degradation during the nuclear power plant operation. This paper discusses: • MOV design parameters and design features • The production testing to establish and record MOV baseline functional data and • ASME QME-1-2007 qualification of these MOVs

Countermeasures to Improve LWR Safety Level in Design and Operation by Accident Analyses at Fukushima Daiichi Nuclear Power Plants

2013 ◽  
Author(s):  
Kazumasa Shimizu ◽  
Yuhei Hamada ◽  
Hiroto Sakashita ◽  
Michitsugu Mori
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Natural Circulation ◽  
Critical Role ◽  
Severe Accident ◽  
Simulation Code ◽  
Safety Level ◽  
Plant Operations ◽  
Fukushima Daiichi ◽  
Water Reactors

The 2011 off the Pacific coast of Tohoku Earthquake occurred on March 11. The earthquake attacked the Fukushima Daiichi nuclear power station with six boiling water reactors (BWRs), three out of which, units 1 through 3 in rated operation except for three reactors of units 4 through 6 in scheduled periodic inspection, automatically shut down in response to the intense seismic motion. Emergency diesel generators started to pump water to cool reactors, and an hour later, the back-up generators lost their all functions by the station blackout resulting from tsunami flooding. In this situation at the unit 1, the isolation condenser system (IC) should have made a critical role to keep the reactor pressure and water level to be safety by removing the decay heat by natural circulation. In fact at the unit 1 during the accident, IC valves were closed by fail-safe and could not have shown the ability of the designed function. An accident report gave general descriptions of the causes and results of accidents, but not the quantitative data indicative of details; therefore, it seems difficult to identify the specific problems in plant operations. Even in this case, if an appropriate analysis code is available for reproducing events based on the reports, it will be possible to determine individual data quantitatively and identify problems in plant operations. In our work, we used the nuclear reactor thermal-hydraulic code RETRAN-3D/MOD4, which has been approved and licensed by U.S. Nuclear Regulatory Commission, to model light water reactors (LWRs) and reproduce the circumstances of the 2011 Fukushima Daiichi nuclear accident as the simulation code. Here, we subjected transition analyses of the process on the core-meltdown accident, and put forward the system to prevent the accident, where the accident analysis report was employed to simulate conditions of the accident. It could enable us to suggest adequate operation procedures suitable for LWR to avoid the severe accident, and to propose countermeasures to improve LWR safety level in design and operation.

Robotics in the Nuclear Environment: Inspection and Repairs Inside the Primary Coolant System

2004 ◽  
Author(s):  
Marcel Tortolano ◽  
Jacques Guillet
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Cost Effective ◽  
Primary Coolant ◽  
Pressurized Water ◽  
Nuclear Plants ◽  
Plant Operations ◽  
On Line ◽  
The Cost

EDF is the French national power generating utility. It has built and operates 58 pressurized water reactor (PWR) nuclear power plants on 19 sites. Of these, thirty-four are 900 megawatt units (the first of which, the Fessenheim NPP, came on line in 1977), twenty are 1300 MW units, and four are 1450 MW units, the latest of which, at the Civaux plant, came on line in 1998. The average age of these nuclear power plants is thus 20 years. They produce close to 85% of the power EDF generates in France. Renewal of the nuclear plants is under study, as are other means of power generation. For the moment, EDF is requesting approval to run its nuclear plants for up to 40 years. Moreover, it has started a major project on the lifetime of PWR reactors, the main objective of which is to extend the authorized lifetime to 60 years. Major requirements for maintaining the current performance of the French nuclear generating facility and reducing the cost per kWh generated include optimization of expenses and reduction of fuel costs. These factors enabled the cost per kWh to be reduced by 13% in 2001. One way to reduce costs involves optimization of maintenance programs and methods. However, increasing the operating lifetime of plants, and the concomitant ageing of equipment and materials, is likely to result in increasing maintenance requirements. For this reason it is important to establish new, more cost-effective maintenance methods in order to keep costs down. Some of these methods make use of robotics. They make it possible for work to be carried out from the inside of circuits, for inspections and even for repair if defects are detected. The results presented here are those of work carried out by the EDF R&D division on behalf of the Nuclear Power Plant Operations (NPPO) division.

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