scholarly journals Searches for sterile neutrinos at the DANSS experiment

2019 ◽  
Vol 219 ◽  
pp. 08002
Author(s):  
Mark Shirchenko ◽  
Nataliya Skrobova
Keyword(s):  
Nuclear Power ◽  
Plastic Scintillator ◽  
Reactor Core ◽  
Sterile Neutrinos ◽  
Positron Energy ◽  
Inverse Beta Decay ◽  
Cosmic Background ◽  
Wide Range ◽  
Reactor Building ◽  
On Line

DANSS is a highly segmented 1 m3 plastic scintillator detector. The DANSS detector is placed under an industrial 3.1 GWth reactor of the Kalinin Nuclear Power Plant 350 km NW from Moscow. The distance to the core is varied on-line from 10.7 m to 12.7 m. The reactor building provides about 50 m water-equivalent shielding against the cosmic background. DANSS detects almost 5000 νe per day at the closest position with the cosmic background less than 3%. The inverse beta decay process is used to detect νe. Sterile neutrinos are searched for assuming the 4ν model (3 active and 1 sterile ν). The exclusion area in the Δm142,sin22θ14 plane is obtained using a ratio of positron energy spectra collected at different distances. Therefore results do not depend on the shape and normalization of the reactor νe spectrum nor the detector efficiency. Results are based on 966 thousand antineutrino events collected at three different distances from the reactor core. The excluded area covers a wide range of the sterile neutrino parameters down to sin22θ14 < 0.01 in the most sensitive region.

scholarly journals New results from the DANSS experiment

2020 ◽  
Vol 35 (34n35) ◽  
pp. 2044015
Author(s):  
Nataliya Skrobova
Keyword(s):  
Nuclear Power ◽  
Sterile Neutrino ◽  
Reactor Core ◽  
Detector Efficiency ◽  
Sterile Neutrinos ◽  
Inverse Beta Decay ◽  
Systematic Uncertainties ◽  
Interesting Part ◽  
Raster Scan ◽  
Kalinin Nuclear Power Plant

We present new results of the DANSS experiment on the searches for sterile neutrinos. They are based on more than 2 million of inverse beta decay events collected at 10.7 m, 11.7 m and 12.7 m from the reactor core of the 3.1 GW Kalinin Nuclear Power Plant in Russia. This data sample is 2.4 times larger than the data sample in the previous DANSS publication. The search for the sterile neutrinos is performed using the ratio of [Formula: see text] spectra at two distances. This method is very robust against systematic uncertainties in the [Formula: see text] spectrum and the detector efficiency. We do not see any statistically significant sign for the [Formula: see text] oscillations. This allows us to exclude further a large and interesting part of the sterile neutrino parameter space. A Gaussian CL[Formula: see text] method was used to obtain exclusion areas. This method is more conservative than a Raster Scan method.

On Line Monitoring the Reactor Power Distribution Based on the Data Library of the Eigenfunctions

2010 ◽  
Author(s):  
Changhui Wang ◽  
Hongchun Wu ◽  
Liangzhi Cao
Keyword(s):  
Power Distribution ◽  
High Speed ◽  
Nuclear Power ◽  
Reactor Core ◽  
Reactor Power ◽  
The Real ◽  
Numerical Result ◽  
On Line ◽  
Relative Errors ◽  
Data Library

A method of on-line monitoring for commercial PWRs using eigenfunctions has been proposed in prevenient works. In this method, the eigenfunctions combine with the detector readings are used to reconstruct the real reactor power distribution. But it is very difficult to choose the eigenfunctions because the condition of the reactor is much complex. Therefore, some improvements on this method are studied in this paper. A number of representational conditions according to the reactor fuel management are picked up to create a data library of different eigenfunctions. On the monitoring process, the computer will judge that which represen6tational conditions most close to the real reactor condition and choose the eigenfunctions which will be used to reconstruct the reactor core power distribution combine with the detector readings. A reactor of Qinshan Nuclear Power Corporation is studied here as an example. The detector readings are from the simulator. The numerical result shows that this method can reconstruct the reactor power distribution with high speed (about 0.03 seconds for each step) and high accuracy (the relative errors are lower than 3% mostly).

scholarly journals Antineutrino Flux from the Laguna Verde Nuclear Power Plant

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Marisol Chavez-Estrada ◽  
Alexis A. Aguilar-Arevalo
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Plastic Scintillator ◽  
Reactor Core ◽  
Simulation Code ◽  
Fission Fragments ◽  
Antineutrino Flux ◽  
Laguna Verde ◽  
Reactor Cores

We present a calculation of the antineutrino flux produced by the reactors at the Laguna Verde Nuclear Power Plant in México, based on the antineutrino spectra produced in the decay chains of the fission fragments of the main isotopes in the reactor core, and their fission rates, which have been calculated using the DRAGON simulation code. We also present an estimate of the number of expected events in a detector made of plastic scintillator with a mass of 1 ton, at 100 m from the reactor cores.

Recent Progress and Plans in Computer-Controlled High Resolution Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 154-155
Author(s):  
W.J. de Ruijter ◽  
Peter Rez ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
Digital Processing ◽  
High Resolution Electron Microscopy ◽  
Objective Lens ◽  
Linear Filter ◽  
Contrast Transfer Function ◽  
Image Displacement ◽  
Spatially Resolved ◽  
Wide Range ◽  
On Line

Digital computers are becoming widely recognized as standard accessories for electron microscopy. Due to instrumental innovations the emphasis in digital processing is shifting from off-line manipulation of electron micrographs to on-line image acquisition, analysis and microscope control. An on-line computer leads to better utilization of the instrument and, moreover, the flexibility of software control creates the possibility of a wide range of novel experiments, for example, based on temporal and spatially resolved acquisition of images or microdiffraction patterns. The instrumental resolution in electron microscopy is often restricted by a combination of specimen movement, radiation damage and improper microscope adjustment (where the settings of focus, objective lens stigmatism and especially beam alignment are most critical). We are investigating the possibility of proper microscope alignment based on computer induced tilt of the electron beam. Image details corresponding to specimen spacings larger than ∼20Å are produced mainly through amplitude contrast; an analysis based on geometric optics indicates that beam tilt causes a simple image displacement. Higher resolution detail is characterized by wave propagation through the optical system of the microscope and we find that beam tilt results in a dispersive image displacement, i.e. the displacement varies with spacing. This approach is valid for weak phase objects (such as amorphous thin films), where transfer is simply described by a linear filter (phase contrast transfer function) and for crystalline materials, where imaging is described in terms of dynamical scattering and non-linear imaging theory. In both cases beam tilt introduces image artefacts.

A Wide Range Ge Gamma-Ray Spectrometer for on-Line Measurements of Reactor Cooling Water Activity

1977 ◽  
Vol 24 (1) ◽  
pp. 673-677 ◽  
Author(s):  
J. J. Lipsett ◽  
I. L. Fowler ◽  
R. J. Dinger ◽  
H. L. Malm
Keyword(s):  
Water Activity ◽  
Gamma Ray ◽  
Cooling Water ◽  
Gamma Ray Spectrometer ◽  
Wide Range ◽  
On Line

scholarly journals Online Simulation of Nuclear Power Plant Primary Systems

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Hongyun Xie ◽  
Haixia Gu ◽  
Chao Lu ◽  
Jialin Ping
Keyword(s):  
Information System ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Real Time ◽  
Nuclear Power ◽  
Measurement Data ◽  
Reactor Core ◽  
Power Industry ◽  
Nuclear Power Industry ◽  
Online Simulation

Real-time Simulation (RTS) has long been used in the nuclear power industry for operator training and engineering purposes. And, online simulation (OLS) is based on RTS and with connection to the plant information system to acquire the measurement data in real time for calibrating the simulation models and following plant operation, for the purpose of analyzing plant events and providing indicative signs of malfunctioning. OLS has been applied in certain industries to improve safety and efficiency. However, it is new to the nuclear power industry. A research project was initiated to implement OLS to assist operators in certain critical nuclear power plant (NPP) operations to avoid faulty conditions. OLS models were developed to simulate the reactor core physics and reactor/steam generator thermal hydraulics in real time, with boundary conditions acquired from plant information system, synchronized in real time. The OLS models then were running in parallel with recorded plant events to validate the models, and the results are presented.

Flow and Temperature Fields Measurement Inside Rod Bundle by the Combined Use of PIV and LIF Technique

2018 ◽  
Author(s):  
Xing Li ◽  
Sichao Tan ◽  
Zhengpeng Mi ◽  
Peiyao Qi ◽  
Yunlong Huang
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Great Influence ◽  
Reactor Core ◽  
Transfer Characteristic ◽  
Index Of Refraction ◽  
Temperature Fields ◽  
Spacer Grid ◽  
Rod Bundle ◽  
Combined Use

Thermal hydraulic research of reactor core is important in nuclear energy applications, the flow and heat transfer characteristics of coolant in reactor fuel assembly has a great influence on the performance and safety of nuclear power plants. Particle image velocimetry (PIV) and Laser induced fluorescence (LIF) are the instantaneous, non-intrusive, whole-field fluid mechanics measuring method. In this study, the simultaneous measurement of flow field and temperature field for a rod bundle was conducted using PIV and LIF technique. A facility system, utilizing the matching index of refraction approach, has been designed and constructed for the measurement of velocity and temperature in the rod bundle. In order for further study on complex heat and mass transfer characteristic of rod bundle, the single-phase experiments on the heating conditions are performed. One of unique characteristics of the velocity and temperature distribution downstream the spacer grid was obtained. The experimental results show that the combined use of PIV and LIF technique is applied to the measurement of multi-physical field in a rod bundle is feasible, the measuring characteristics of non-intrusive ensured accuracy of whole field data. The whole field experimental data obtained in rod bundle benefits the design of spacer grid geometry.

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