scholarly journals First horizontal and first vertical derivatives from high resolution aeromagnetic data over the Gongola basin upper Benue trough Northeastern Nigeria

2021 ◽  
Vol 27 (2) ◽  
pp. 181-192
Author(s):  
Musa Hayatudeen ◽  
Bello Rasaq ◽  
Raheem I Onaolapo ◽  
Ayoola Olumide Abe
Keyword(s):  
High Resolution ◽  
Nuclear Power ◽  
Power Plants ◽  
Average Power ◽  
Mineral Resources ◽  
Aeromagnetic Data ◽  
Linear Structures ◽  
Benue Trough ◽  
Risk Areas ◽  
Data Investigation

High-resolution aeromagnetic data investigation was carried out over the Gongola basin upper Benue trough northeastern Nigeria. Total intensity magnetic map were processed to get the residual map, reduction to equator, polynomial fitting, radially average power spectrum (RAPS) were done, subsequently the first horizontal and first vertical derivatives of the data was carried out in order to identify linear structures (faults and fractures). The outcomes from both the horizontal and vertical derivatives give contact locations that are continuous, thin and show major structures in the NE-SW direction both in the maps and in the rose diagrams. The study focused on delineation of geological structures such as rock contacts; rock boundaries, fractures and faulted zones from the maps, they are principally important in mineral resources studies because many of these resources are located along fracture zones. Linear structures perceived in this kind of studies are also reliable indicators for geologic structures. The result of this work is also significant in identifying areas to be avoided when constructing bridges, dams as well as siting nuclear power plants and delineation of potential risk areas of natural hazard. Keywords: Aeromagnetic Data, first Horizontal Derivative, first Vertical Derivatives, Gongola Basin, Linear Features.

scholarly journals Analytic Signal Depth from High Resolution Aeromagnetic Data over the Gongola Basin Upper Benue Trough Northeastern Nigeria

2021 ◽  
Vol 25 (4) ◽  
pp. 585-590
Author(s):  
H. Musa ◽  
N.E. Bassey ◽  
R. Bello
Keyword(s):  
High Resolution ◽  
Magnetic Structure ◽  
Horizontal Cylinder ◽  
Analytic Signal ◽  
Aeromagnetic Data ◽  
Polynomial Fitting ◽  
Benue Trough ◽  
Local Maxima ◽  
Depth Determination ◽  
Programming Software

The study of high-resolution aeromagnetic data was carried out over the Gongola basin, upper Benue trough, northeastern Nigeria, for analytic signal depth determination. Total intensity magnetic map obtained from the data using the Oasis Montaj TM programming software was used to get the residual map by polynomial fitting, from where the analytic signal was obtained with the use of anomaly width at half the amplitude (X1/2). This was used to carry out depth estimations over the study area. The results showed that it peaks over the magnetic structure with local maxima over its edges (boundaries or contact), and the amplitude is simply related to magnetization, likewise results also showed that the depth estimates were in the range of 1.2 to 5.9 km and were calculated for contact, dyke/sill and horizontal cylinder respectively. The lowest values are from DD profiles, while the highs are from AA profiles. This work is important in identifying dykes, contacts and intrusives over an area.

scholarly journals Initial Spread of <sup>137</sup>Cs over the shelf of Japan: a study using the high-resolution global-coastal nesting ocean model

2013 ◽  
Vol 10 (2) ◽  
pp. 1929-1955 ◽  
Author(s):  
Z. Lai ◽  
C. Chen ◽  
R. Beardsley ◽  
H. Lin ◽  
R. Ji ◽  
...  
Keyword(s):  
High Resolution ◽  
Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Current Model ◽  
Tohoku Earthquake ◽  
Ocean Model ◽  
Grid Resolution ◽  
The 2011 Tohoku Earthquake ◽  
Conservative Tracer

Abstract. The 2011 Tohoku earthquake caused radionuclide 137Cs be directly released into the ocean from the Fukushima Dai-ichi nuclear power plants. A high-resolution global-coastal nesting ocean model was established to simulate the initial spread of 137Cs as conservative tracer over the shelf of Japan after the accident. The major advantage in the current model system is to use unstructured grids to resolve the power plant and the coastal geometry with a grid resolution much higher than that used in previous modeling experiments. Therefore, it gives us an opportunity to examine the necessity whether the detailed structure of the Power plant should be considered for numerical experiment of 137Cs dispersion or not. This could provide us an alternative insight into the physical processes that lead to its spread of 137Cs over the shelf of Japan. Our results suggested that to resolve the dispersion process from the source point to the south and north discharging canal is critical for an accurate prediction of the spread of 137Cs to the 30 km sites off the coast. Moreover, a 2 km grid resolution along Japan coast is probably not high enough to resolve the plume correctly. Finally, the model-data comparison suggested that the physical process associated with the transfer of dissolved 137Cs into the sediment phase could potentially be important and should be considered in the future tracer modeling.

Risks for Flow Induced Vibrations (FIV) at EPU

2008 ◽  
Author(s):  
Per Nilsson ◽  
Eric Lillberg
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Cross Flow ◽  
Flow Induced Vibration ◽  
Resonance Vibrations ◽  
Flow Induced Vibrations ◽  
Risk Areas ◽  
Tube Banks ◽  
Semi Empirical ◽  
Simple Search

This work deals with risk areas for flow induced vibration at extended power uprate, EPU. The focus is on the mechanisms of excitation in one phase relevant for Swedish BWRs and PWRs. FIV-events that have occurred in nuclear power plants over the world have been collected and categorized. The most relevant events for EPU are summarized to: vibrations in steam systems due to turbulence or vortex shedding and resonance, vibrations of internal parts and also thermal mixers and sleeves or in valves and vibrations of tube banks in partial or full cross flow. Based on the collected events and some semi-empirical methods, a simple search list for FIV by power uprate has been developed. In principle these changes lead to increased risks: changed flow velocity, decreased water temperature and increased steam temperature and decreased structural damping, mass or stiffness. In addition to that, the typical collected events should be regarded.

Optimization of Small Long Life Gas Cooled Fast Reactors with Natural Uranium as Fuel Cycle Input

2012 ◽  
Vol 260-261 ◽  
pp. 307-311 ◽  
Author(s):  
Menik Ariani ◽  
Z. Su'ud ◽  
Fiber Monado ◽  
A. Waris ◽  
Khairurrijal ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Fuel Cycle ◽  
Volume Fraction ◽  
Natural Circulation ◽  
Average Power ◽  
Natural Uranium ◽  
Energy Utilization ◽  
Fast Reactors ◽  
Long Life

In this study gas cooled reactor system are combined with modified CANDLE burn-up scheme to create small long life fast reactors with natural circulation as fuel cycle input. Such system can utilize natural Uranium resources efficiently without the necessity of enrichment plant or reprocessing plant. Therefore using this type of nuclear power plants optimum nuclear energy utilization including in developing countries can be easily conducted without the problem of nuclear proliferation. In this paper, optimization of Small and Medium Long-life Gas Cooled Fast Reactors with Natural Uranium as Fuel Cycle Input has been performed. The optimization processes include adjustment of fuel region movement scheme, volume fraction adjustment, core dimension, etc. Due to the limitation of thermal hydraulic aspects, the average power density of the proposed design is selected about 75 W/cc. With such condition we investigated small and medium sized cores from 300 MWt to 600 MWt with all being operated for 10 years without refueling and fuel shuffling and just need natural Uranium as fuel cycle input. The average discharge burn-up is about in the range of 23-30% HM.

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