scholarly journals Hydrazine Radiolysis by Gamma-Ray in the N2H4–Cu+–HNO3 System

2021 ◽  
Vol 22 (14) ◽  
pp. 7376
Author(s):  
Naon Chang ◽  
Huijun Won ◽  
Sangyoon Park ◽  
Heechul Eun ◽  
Seonbyeong Kim ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Gamma Ray ◽  
Uv Spectroscopy ◽  
Radiolysis Product ◽  
Decomposition Mechanism ◽  
Irradiation Condition ◽  
High Dose ◽  
Hno3 Solution ◽  
Γ Ray

Radiolysis of chemical agents occurs during the decontamination of nuclear power plants. The γ-ray irradiation tests of the N2H4–Cu+–HNO3 solution, a decontamination agent, were performed to investigate the effect of Cu+ ion and HNO3 on N2H4 decomposition using a Co-60 high-dose irradiator. After the irradiation, the residues of N2H4 decomposition were analyzed by Ultraviolet-visible (UV) spectroscopy. NH4+ ions generated from N2H4 radiolysis were analyzed by ion chromatography. Based on the results, the decomposition mechanism of N2H4 in the N2H4–Cu+–HNO3 solution under γ-ray irradiation condition was derived. Cu+ ions form Cu+N2H4 complexes with N2H4, and then N2H4 is decomposed into intermediates. H+ ions and H● radicals generated from the reaction between H+ ion and eaq− increased the N2H4 decomposition reaction. NO3− ions promoted the N2H4 decomposition by providing additional reaction paths: (1) the reaction between NO3− ions and N2H4●+, and (2) the reaction between NO● radical, which is the radiolysis product of NO3− ion, and N2H5+. Finally, the radiolytic decomposition mechanism of N2H4 obtained in the N2H4–Cu+–HNO3 was schematically suggested.

Characterization Of A Lanthanum Bromide Detector For Eye Lens Dosimetry At The Candu Nuclear Power Plants Based On Direct Measurements Of The Gamma-Ray Spectra

2020 ◽  
Author(s):  
A S Laranjeiro ◽  
F Bohra ◽  
S H Byun ◽  
J Atanackovic ◽  
A R Hanu
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Pulse Shaping ◽  
Nuclear Power Plants ◽  
Gamma Ray ◽  
Absorbed Dose ◽  
Eye Lens ◽  
High Dose ◽  
Candu Reactors ◽  
Radiation Fields

Abstract Gamma-ray spectra were measured using a LaBr$_{3}$(Ce) spectrometer during the outage periods, aiming at quantifying the gamma source term of radiation workers’ exposure, at the CANDU nuclear power reactors, for the purposes of eye lens dosimetry. The spectra were measured inside the boiler rooms, of the Bruce Power and Ontario Power Generation (OPG) CANDU nuclear power plants, where workers are exposed to relatively high dose rates radiation fields during the maintenance work. Prior to measurements at the CANDU reactors, the pulse shaping parameters of the gamma spectrometer were optimised for high rates gamma fields, up to an input rates of 120 kcps, in order to accomplish a high output rate with a reasonable energy resolution. In parallel, the response of the LaBr$_{3}$(Ce) detector was characterized by experiments and Monte Carlo simulations. The gamma spectra measured at the CANDU reactors were reported in terms of the gamma-ray fluence rate spectrum. In all measured data, $^{60}$Co and $^{95}$Nb were main contributors of the gamma fields. The measured spectra have been used to calculate the dosimetric quantities of interest: personal dose equivalents H$_{p}$(10) and H$_{p}$(0.07) and eye lens absorbed dose.

Design, calibration, and application of an airborne gamma spectrometer system in Switzerland

Geophysics ◽  
1997 ◽  
Vol 62 (5) ◽  
pp. 1369-1378 ◽  
Author(s):  
Georg F. Schwarz ◽  
Ladislaus Rybach ◽  
Emile E. Klingelé
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Gamma Ray ◽  
Point Sources ◽  
Swiss Alps ◽  
Artificial Radioactivity ◽  
Radiation Level ◽  
Satellite Navigation System ◽  
Emergency Situations

Airborne radiometric surveys are finding increasingly wider applications in environmental mapping and monitoring. They are the most efficient tool to delimit surface contamination and to locate lost radioactive sources. To secure radiometric capability in survey and emergency situations, a new sensitive airborne system has been built that includes an airborne spectrometer with 256 channels and a sodium iodide detector with a total volume of 16.8 liters. A rack mounted PC with memory cards is used for data acquisition, with a GPS satellite navigation system for positioning. The system was calibrated with point sources using a mathematical correction to take into account the effects of gamma‐ray scattering in the ground and in the atmosphere. The calibration was complemented by high precision ground gamma spectrometry and laboratory measurements on rock samples. In Switzerland, two major research programs make use of the capabilities of airborne radiometric measurements. The first one concerns nuclear power plant monitoring. The five Swiss nuclear installations (four power plants and one research facility) and the surrounding regions of each site are surveyed annually. The project goal is to monitor the dose‐rate distribution and to provide a documented baseline database. The measurements show that all sites (with the exception of the Gösgen power plant) can be identified clearly on the maps. No artificial radioactivity that could not be explained by the Chernobyl release or earlier nuclear weapons tests was detected outside of the fenced sites of the nuclear installations. The second program aims at a better evaluation of the natural radiation level in Switzerland. The survey focused on the crystalline rocks of the Central Massifs of the Swiss Alps because of their relatively high natural radioactivity and lithological variability.

Effect of γ-ray irradiation on performance of LiNbO(3)-based piezoelectric vibration sensors

2021 ◽  
Author(s):  
Huifen Wei ◽  
Wenping Geng ◽  
Kaixi Bi ◽  
Tao Li ◽  
Xiangmeng Li ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Extreme Environments ◽  
Theoretical Work ◽  
High Dose ◽  
Mems Devices ◽  
Micro Electro Mechanical Systems ◽  
Vibration Sensors ◽  
Irradiation Dosage ◽  
Gamma Ray Irradiation ◽  
Γ Ray

Abstract LiNbO3 (LN)-based micro-electro-mechanical systems (MEMS) vibration sensors exhibit giant prospection in extreme environments, where exist a great amount of irradiation. However, to the best of our knowledge, it is still unknown whether the irradiation affects the performance of LN-based piezoelectric MEMS sensors. Based on this consideration, it is necessary to model the irradiation environment to investigate the effect of high dosage irradiation on LN-based vibration sensors. Firstly, the theoretical work is done to study the Compton Effect on the Gamma-ray irradiation with Co-60 source. After irradiation, X-ray diffraction (XRD) characterization was performed to verify the effect of irradiation on the crystalline of LN thin film. Meanwhile, the performances of output voltages on the five MEMS devices under various dosage of irradiation are compared. As a result, a neglected shift of 0.02 degrees was observed from the XRD image only under maximum irradiation dosage of 100 Mrad(Si). Moreover, the output voltages of cantilever-beam vibration sensors decrease by 3.1%. Therefore, it is verified that the γ-ray irradiation has very little influence on the LN-based MEMS vibration sensors, which have great attraction on the materials and sensors under high-dose irradiation.

Remote-Controlled Inspection Robot for Nuclear Facilities in Underwater Environment

2009 ◽  
Author(s):  
Harunobu Okihana ◽  
Keiji Iwata ◽  
Yasuhiro Miwa
Keyword(s):  
Radiation Exposure ◽  
Nuclear Power ◽  
Power Plants ◽  
Ccd Camera ◽  
High Dose ◽  
Nuclear Facilities ◽  
Original Design ◽  
Inspection Robot ◽  
Manual Inspection ◽  
Underwater Environment

A remote-controlled inspection robot for nuclear facilities in underwater environment was developed. The Array system of Eddy Current Testing (Array-ECT) is installed on the existing robot that consists of the driving unit and the inspection unit with enlarged Charge-Coupled Device (CCD) camera. It can swim in the tank, crawl on the inner surface of the tank, stay on the inspection area and by its two devices, Array-ECT and enlarged CCD camera, start inspection. Array-ECT can record the color contour image, and also can display oscillograph. This technology had been developed in order to reduce worker’s radiation exposure and improve inspection-ability in nuclear power plants for some Radioactive Waste (RW) tanks. With conventional manual inspection, RW tanks must be examined with the sequence of (a) full drainage and decontamination, (b) scaffolding set-up with workers under high dose, and (c) manual inspection. As such, the inspection is time consuming and workers should have high radiation exposure. With the original robot that has only enlarged CCD camera, inspection can be performed without tank drainage and with minimum worker’s radiation exposure. However, it needs experienced inspector for interpretation of visual examination using enlarged CCD camera. Newly developed robot with Array-ECT and enlarged CCD camera can achieve the same performance using the original robot and an experienced inspector for visual inspection using enlarged CCD camera. The new feature added to the original design (i.e. Array-ECT) eliminates the need for an experienced inspector.

scholarly journals Effects of gamma radiation induced forced formation of free radicals on the strength of concrete for use in nuclear power plants

2017 ◽  
Vol 32 (4) ◽  
pp. 307-319
Author(s):  
Steven Burnham ◽  
Quentin Faure ◽  
Michelle Tamplin ◽  
Long Huang ◽  
Tatjana Jevremovic
Keyword(s):  
Compressive Strength ◽  
Free Radicals ◽  
Gamma Radiation ◽  
Nuclear Power ◽  
Power Plants ◽  
High Dose ◽  
Short Term Exposure ◽  
Radiation Induced ◽  
Increased Strength

In this paper, we present a summary of preliminary experiments and numerical assessments of the effects of gamma radiation induced formation of free radicals in the curing stage of concrete on its characteristics. Substantial literature reports on the damaging effects of long-term and high-dose gamma and neutron exposure on concrete. However, we show that short-term exposure of concrete to gamma radiation can be beneficial in increasing its compressive strength. The effects of exposing to 630 MBq 137Cs the 56 cubes each made of 125 cm3 concrete during the first seven days of curing are compared to another 56 cubes cured by the conventional process. The average compressive strength of the gamma cured cubes is around 8.500 psi, while conventionally cured cubes show the lower average strength of around 6.700 psi. The microstructure of the gamma and conventionally cured concrete cubes is analyzed using a scanning electron microscope. The radiolysis within the microstructure of the concrete cubes is assessed with computational modeling based on Geant4. The production of free radicals from radiolysis is shown to increase with increasing source strength and increasing the time of exposure to gamma radiation. This research shows in general that curing concrete in gamma radiation field provides observable trends toward its increased strength.

scholarly journals The Characterization of Silicone-Tungsten-Based Composites as Flexible Gamma-Ray Shields

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5970
Author(s):  
Jie Wang ◽  
Haoyu Zhou ◽  
Yong Gao ◽  
Yupeng Xie ◽  
Jing Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Tensile Property ◽  
Nuclear Power ◽  
Power Plants ◽  
Degrees Of Freedom ◽  
Gamma Ray ◽  
Tensile Elongation ◽  
Nano Tio2 ◽  
Attenuation Coefficients ◽  
Structural Investigations

Robots are very essential for modern nuclear power plants to monitor equipment conditions and eliminate accidents, allowing one to reduce the radiations on personnel. As a novel robot, a soft robot with the advantages of more degrees of freedom and abilities of continuously bending and twisting has been proposed and developed for applications in nuclear power industry. Considering the radiation and high-temperature environment, the overall performance improvement of the flexible materials used in the soft nuclear robot, such as the tensile property and gamma-ray shielding property, is an important issue, which should be paid attention. Here, a flexible gamma-ray shielding material silicone-W-based composites were initially doped with nano titanium oxide and prepared, with the composition of 20 silicone-(80-x) W-(x) TiO2, where x varied from 0.1 to 2.0 wt.%. Structural investigations on SEM and EDS were performed to confirm the structure of the prepared composites and prove that all the chemicals were included in the compositions. Moreover, the tensile property of the composites at 25, 100, and 150 °C were investigated to study the effect of working temperature on the flexibility of the compositions. The attenuation characteristics including the linear attenuation coefficients and mass attenuation coefficients of the prepared silicone-W or silicone-W-TiO2-based composites with respect to gamma ray were investigated. The stability of the silicone–tungsten-TiO2-based composite at high temperature was studied for the first time. In addition, the influence of nano TiO2 additive on the property’s variation of silicone-W-based composites was initially studied. The comparison of the properties such as the tensile elongation, thermal stability, and gamma-ray shielding of the synthesized silicone-W and silicone-W-TiO2 composites showed that the addition of nano TiO2 powders could be useful to develop novel gamma-ray-shielding materials for radiation protection of soft robots or other applications for which soft gamma-ray-shielding materials are needed.

Development of an Efficient Tool for Evaluating Dose at Through-Holes

2020 ◽  
Author(s):  
Tatsuya Watanabe ◽  
Hironobu Iwanami ◽  
Tomoharu Hashimoto ◽  
Ryuichi Tayama
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Gamma Ray ◽  
Integration Method ◽  
Computation Time ◽  
Simple Calculation ◽  
Detailed Calculation ◽  
Calculation Formula ◽  
Evaluation Point ◽  
Kernel Integration

Abstract In the design of nuclear power plants, it is demanded to quickly and calculate gamma ray scattering line (streaming) from the penetrating portion provided in the shielding such as electrical cables and ducts. However, when conducting gamma-ray streaming calculations from multiple penetrations, MCNP, a detailed calculation code, requires a long calculation time. This is due to the nature of MCNP, where many particles must reach the evaluation point when calculating in order for the results to be within an acceptable accuracy. To shorten the computation time, an analysis code utilizing a simple calculation method is necessary. Thus, we have developed a new method and a simple calculation tool (SVD-Dorc) for streaming computation. This method combines dose rate at an evaluation point with point kernel integration method and a simple streaming calculation formula for straight cylindrical ducts. Properties of SVD-Dorc are as follows: • Point kernel integration method • Simple streaming calculation formula for straight cylindrical ducts • Manual and automatic meshing of rectangular and cylindrical sources • Differentiation between direct line and non-direct sources • 3D drawing of input data • File output The validity of SVD-Dorc was confirmed by comparison with MCNP calculations and measured values from benchmark tests [2].

scholarly journals A Performance Evaluation of a Notebook PC under a High Dose-Rate Gamma Ray Irradiation Test

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Jai Wan Cho ◽  
Kyung Min Jeong
Keyword(s):  
Performance Evaluation ◽  
Dose Rate ◽  
Nuclear Power ◽  
Gamma Ray ◽  
Control Unit ◽  
High Dose Rate ◽  
High Dose ◽  
Robot System ◽  
Irradiation Test ◽  
Gamma Ray Irradiation

We describe the performance of a notebook PC under a high dose-rate gamma ray irradiation test. A notebook PC, which is small and light weight, is generally used as the control unit of a robot system and loaded onto the robot body. Using TEPCO’s CAMS (containment atmospheric monitoring system) data, the gamma ray dose rate before and after a hydrogen explosion in reactor units 1–3 of the Fukushima nuclear power plant was more than 150 Gy/h. To use a notebook PC as the control unit of a robot system entering a reactor building to mitigate the severe accident situation of a nuclear power plant, the performance of the notebook PC under such intense gamma-irradiation fields should be evaluated. Under a similar dose-rate (150 Gy/h) gamma ray environment, the performances of different notebook PCs were evaluated. In addition, a simple method for a performance evaluation of a notebook PC under a high dose-rate gamma ray irradiation test is proposed. Three notebook PCs were tested to verify the method proposed in this paper.

Innovative Robot Technologies for Nuclear Power Plants Inspection and Maintenance

2014 ◽  
Author(s):  
Seungho Kim ◽  
Kyung Min Jung ◽  
Sung Uk Lee ◽  
Hocheol Shin ◽  
Chang Hoi Kim ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
High Dose ◽  
Nuclear Facilities ◽  
Human Errors ◽  
Safety Issues ◽  
Safety And Reliability ◽  
Inspection And Maintenance ◽  
Remote Inspection

Nuclear energy has become the main energy source in Korea, but the safety issues are being debated since the Fukusima accident. In order to guarantee the safety and reliability of nuclear power plants, the uncertainty of human errors are being minimized by utilizing innovative technologies for inspection and maintenance. KAERI has developed robotic systems to upgrade and ensure the safety of nuclear facilities, to detect unusual conditions of facilities through remote inspection and to prevent human workers from high dose radiation with efficient plant maintenance.

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