scholarly journals Preliminary Assessment of Cooling Water Chemistry for Fusion Power Plants

2021 ◽  
Vol 2 (3) ◽  
pp. 512-530
Author(s):  
Eugenio Lo Piccolo ◽  
Raffaele Torella ◽  
Nicholas Terranova ◽  
Luigi Di Pace ◽  
Claudia Gasparrini ◽  
...  
Keyword(s):  
Water Chemistry ◽  
Power Plants ◽  
Cooling Water ◽  
Computer Code ◽  
Dual Approach ◽  
Corrosion Susceptibility ◽  
Definition Of ◽  
Under Construction ◽  
Additional Safety

The determination of the water chemistry for cooling systems of nuclear fusion plants is under debate. It should be tailored for different types of fusion reactors: either experimental, e.g., ITER, JT-60SA, and DTT, or aimed at power generation, e.g., DEMO, given the different operation requirements. This paper presents the dual approach involving experiments and computer simulations chosen for the definition of DEMO water chemistry. Experimental work was performed to assess the corrosion susceptibility of reduced activation ferritic martensitic EUROFER 97 and AISI 316L in different water chemistry regimes. At the same time, the low corrosivity requirement brings an additional safety aspect for the radiation protection since some neutron-activated corrosion products (ACPs) create a gamma radiation when deposited outside the plasma chamber in components accessible to operators and these must be minimized. To evaluate the ACP inventory for DEMO, assessments were carried out using a reference computer code. Preliminary experimental activities to define the water chemistry of DTT under construction at ENEA were also conducted. The comparison of code results with experiments is two-fold important: for the validation of the computer code models and to determine data that are necessary to perform calculations.

scholarly journals Ion chromatographic analysis of aqueous iodine species by conductivity and radioactivity measurements

2005 ◽  
Vol 93 (9-10) ◽  
Author(s):  
Dorothea Schumann ◽  
R. Grasser ◽  
R. Dressler ◽  
H. Bruchertseifer
Keyword(s):  
Chromatographic Analysis ◽  
Nuclear Power ◽  
Power Plants ◽  
Radioactive Iodine ◽  
Cooling Water ◽  
Molecular Iodine ◽  
New Device ◽  
Iodine Species ◽  
Radioactivity Measurements

SummaryA new device was developed for the identification of several iodine species in aqueous solution using ion chromatography. Iodide, iodate and molecular iodine can be determined. (The equipment allows both conductivity and radioactivity detections.) The method is applicable for the determination of radioactive iodine contaminations in the cooling water of nuclear power plants.

Implementation of an Approach for Characterisation of Radiological Inventory for Decommissioning at Chinon A2 NPP

2014 ◽  
Author(s):  
A. Traichel ◽  
F. Tardy ◽  
M. Mummert
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Statistical Processing ◽  
Analysis Data ◽  
Measured Data ◽  
Primary Circuit ◽  
Measurement Systems ◽  
Definition Of ◽  
Local Sampling

A general overview of the existing radioactive inventory in the plant is necessary for the decommissioning of nuclear power plants. Based on the knowledge about radiological inventory, appropriate decommissioning techniques and procedures can be specifically used. In order to derive the existing radiological activity in the facility a study was carried out to obtain a representative overview of the total radiological situation at the NPP. Within a study a generic methodology for the radiological characterization was developed. This methodology has been applied on the CO2-circuit of the gas-cooled, graphite-moderated reactor Chinon A2 (MAGNOX type). This paper covers the implementation of an approach for characterisation of radiological inventory for decommissioning. The approach aims at the definition of the number and distribution of local sampling, required measurements as well as suitable measurement systems leading to a confident result with minimized effort in sampling. The paper covers two main objectives: 1. Methodology at and 2. Determination of radiological inventory based on measured data. The proposed methodology is a stepwise procedure which offers the possibility for minimizing the number of required measurements/sample analyses. At the first step the underlying system is an “as-simple-as-possible”-example with homogeneous contamination. In a second step the methodology is expanded to a more realistic and complex system, for which additional investigations have to be performed. The determination of the radiological inventory using the methodology has to consider a given confidence level and maximum allowed error. Therefore statistical assessment is widely used in estimations. The result of this first part of study generates the basis for further investigation. This comprises application of methodology to the mentioned technical system. Therefore corresponding measurement and analysis data have to be delivered and proven regarding adequacy for the proposed methodology. From the dataset various measurement systematic and retained parameters could be derived. The accuracy of given measured data was checked by further examination. The result of the performed analysis leads to a statement about the activity in the primary circuit. The result of this study is an comprehensive estimation of the activity by defined statistical processing of analysed data. The result consists moreover of the analysis of the measurement plan and of distribution and deviation within the measured data. Suggestions for further measurement campaigns are provided based on the deviations and inconsistencies of the data. With the help of these suggestions it should be possible to decrease the number of samples and measuring data as well as improve the comparability of separate measurement processes. Particular potential for improvement of the result for inventory can be seen in a deeper analysis of uncertainties, this was realised and will be explained in the paper.

A Generalized Method for the Comparable and Rigorous Calculation of the Polytropic Efficiencies of Turbocompressors

2018 ◽  
Vol 35 (1) ◽  
pp. 35-47
Author(s):  
Panagiotis Dimitrakopoulos
Keyword(s):  
Relative Error ◽  
High Power ◽  
Power Plants ◽  
High Accuracy ◽  
Average Relative Error ◽  
Working Fluid ◽  
Jet Engines ◽  
End Points ◽  
Definition Of

AbstractThe calculation of polytropic efficiencies is a very important task, especially during the development of new compression units, like compressor impellers, stages and stage groups. Such calculations are also crucial for the determination of the performance of a whole compressor. As processors and computational capacities have substantially been improved in the last years, the need for a new, rigorous, robust, accurate and at the same time standardized method merged, regarding the computation of the polytropic efficiencies, especially based on thermodynamics of real gases. The proposed method is based on the rigorous definition of the polytropic efficiency. The input consists of pressure and temperature values at the end points of the compression path (suction and discharge), for a given working fluid. The average relative error for the studied cases was 0.536 %. Thus, this high-accuracy method is proposed for efficiency calculations related with turbocompressors and their compression units, especially when they are operating at high power levels, for example in jet engines and high-power plants.

Analysis of Emergency Staffing for Nuclear Power Plants

1983 ◽  
Vol 27 (2) ◽  
pp. 184-186
Author(s):  
Michael K. Lindell
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Phase Method ◽  
Situational Analysis ◽  
Limited Information ◽  
Staffing Levels ◽  
Definition Of ◽  
Staffing Requirements ◽  
Analysis Determination

Determination of staffing requirements for response to nuclear plant emergencies should be based upon task analysis in order to ensure that emergency functions can be performed in any type of accident. The method of analysis must recognize the differences between personnel performance in normal and emergency conditions and the limited information available for analysis of emergency tasks. A four-phase method is described that consists of generic analysis (identification of general emergency functions and tasks), situational analysis (definition of the characteristics of the classes of emergencies that can occur), quantitative analysis (determination of workloads, by position) and sensitivity analysis (examination of the degree to which changes in assumptions produce changes in required staffing levels).

scholarly journals A VORTEX DROP STRUCTURE AS DEAERATION SYSTEM FOR A SUBMARINE OUTFALL PIPELINE

2018 ◽  
pp. 16
Author(s):  
Rolando García
Keyword(s):  
Power Plants ◽  
Water Discharge ◽  
Thermal Power ◽  
Cooling Water ◽  
Air Entrainment ◽  
Return Flow ◽  
World Bank Group ◽  
Discharge System ◽  
Under Construction ◽  
Drop Structure

Use of submarine outfall pipelines became more common since World Bank Group issued a new guideline for maximum emissions levels for thermal power plants in 1998 (van Dijk, 2005). The more restrictive levels for temperature increase at the receiving water, requires outfall systems to conduct the water down to greater depths to achieve the required dilution standard. However, air entrainment control into outfall pipes could be challenging, especially for discharges with high flowrates for which conventional deaeration chambers become too large. The problem could turn more difficult in coastal shelf areas at seismic zones, where the hydraulic height of the incoming flow must be effectively controlled and the design not only has to pursue hydraulic objectives but also stability requirements for these massive structures subjected to relevant seismic thrusts. A vortex drop structure was designed for the cooling water discharge system of a thermal power plant in Mejillones Bay, Chile. The structure addresses the elevation difference between the return flow pipe and the ocean outfall pipelines while adhering to the spatial restrictions at the project site. Energy dissipation as well as limitation of air entrainment into the outfall pipelines were critical design considerations. Tests where done on a 1:12.5 scale (Froude) physical model. Prototype structure is under construction. Operation is planned to start on mid-2018.

Stator Leakage Monitoring System in Water-Cooled Generators: Problems and Solutions

2021 ◽  
Author(s):  
Thomas Bauer ◽  
Matthias Svoboda
Keyword(s):  
Water Chemistry ◽  
Nuclear Power ◽  
Power Plants ◽  
Large Scale ◽  
Cooling Water ◽  
Injection System ◽  
Technical Solution ◽  
Efficiency Coefficient ◽  
O2 Concentration ◽  
Cooling Media

Abstract An electrical generator is one of the most efficient large-scale machines. It converts mechanical to electrical energy with an efficiency coefficient of approximately 99%. The remaining 1% can mainly be contributed to heat losses. Direct cooling is only necessary for larger turbogenerators with more than 250 MVA where the cooling media is introduced via hollow conductors within the stator bars. Turbogenerators of approximately up to 700 MVA nowadays use exclusively hydrogen (H2) gas as a cooling media. Even larger turbogenerators have to introduce direct water cooling. The water chemistry of the stator cooling water is typically of neutral pH and has a conductivity of less than 0.1 μS/cm. Two zones of the oxygen (O2) concentration have been established through the last 50 years, one at low dissolved O2 concentration with less than 20 ppb, the other with high concentrations of more than 2 ppm. The latter has to continuously inject CO2 free air to ensure to always keep the oxygen concentration above 2 ppm. The first part of this publication shows several incidents with the air injection system in different Nuclear Power Plants in the US, resulting in unfavorable stator cooling water chemistry. This led to a reduced cooling efficiency, resulting in several chemical online cleanings being necessary. The second part of this work presents a technical solution to overcome the issues associated with the reduced stator cooling. It continuously injects and monitors the air injected into the system. Additionally, it also measures the hydrogen leakage rate.

State Failure and the Political Violence Phenomenon: A Comparative Analysis of Iraq and Syria Cases

2016 ◽  
Vol 4 (2) ◽  
pp. 170 ◽  
Author(s):  
K. Eylem Özkaya Lassalle
Keyword(s):  
Cold War ◽  
Political Violence ◽  
State Failure ◽  
The Political ◽  
Collective Violence ◽  
Short Run ◽  
Definition Of ◽  
The Cold War

The concept of failed state came to the fore with the end of the Cold War, the collapse of the USSR and the disintegration of Yugoslavia. Political violence is central in these discussions on the definition of the concept or the determination of its dimensions (indicators). Specifically, the level of political violence, the type of political violence and intensity of political violence has been broached in the literature. An effective classification of political violence can lead us to a better understanding of state failure phenomenon. By using Tilly’s classification of collective violence which is based on extent of coordination among violent actors and salience of short-run damage, the role played by political violence in state failure can be understood clearly. In order to do this, two recent cases, Iraq and Syria will be examined.

Sign in / Sign up

Export Citation Format

Share Document