scholarly journals The Impact of Hydrogen Valence on Its Bonding and Transport in Molten Fluoride Salts

Author(s):  
Stephen T. Lam ◽  
Qing-Jie Li ◽  
Jonathan P. Mailoa ◽  
Charles Forsberg ◽  
Ronald Ballinger ◽  
...  

<p>Interest in molten salts has increased significantly over the last decade due to their potential application in various clean-energy technologies including hydrogen generation, solar heat storage, and advanced nuclear power plants. In the development of new molten salt-based fission and fusion systems, controlling hydrogen poses a critical challenge due to its ability to corrode structural materials as <sup>3</sup>H<sup>+</sup>, and its potential to cause significant radioactive release as diffusive <sup>3</sup>H<sup>0</sup>. Yet, the chemistry and transport behavior of the hydrogen species remain poorly understood despite several decades of research. Using ab initio molecular dynamics, we present a coupled examination of hydrogen valence, speciation and transport in the prototypical salts 66.6%LiF-33.3¾F<sub>2</sub> (Flibe) and 46.5%LiF-11.5%NaF-42%KF (Flinak). We discovered significant differences between <sup>3</sup>H<sup>0</sup> and <sup>3</sup>H<sup>+</sup>transport behaviors. <sup>3</sup>H<sup>+</sup> diffuses 2-4 times slower than <sup>3</sup>H<sup>0</sup>, which can be ascribed to hydrogen bonding and complexation in solution. This work helps explain varying experimental results and provides useful species transport data for designing hydrogen control systems for molten salts. </p>

2020 ◽  
Author(s):  
Stephen T. Lam ◽  
Qing-Jie Li ◽  
Jonathan P. Mailoa ◽  
Charles Forsberg ◽  
Ronald Ballinger ◽  
...  

<p>Interest in molten salts has increased significantly over the last decade due to their potential application in various clean-energy technologies including hydrogen generation, solar heat storage, and advanced nuclear power plants. In the development of new molten salt-based fission and fusion systems, controlling hydrogen poses a critical challenge due to its ability to corrode structural materials as <sup>3</sup>H<sup>+</sup>, and its potential to cause significant radioactive release as diffusive <sup>3</sup>H<sup>0</sup>. Yet, the chemistry and transport behavior of the hydrogen species remain poorly understood despite several decades of research. Using ab initio molecular dynamics, we present a coupled examination of hydrogen valence, speciation and transport in the prototypical salts 66.6%LiF-33.3¾F<sub>2</sub> (Flibe) and 46.5%LiF-11.5%NaF-42%KF (Flinak). We discovered significant differences between <sup>3</sup>H<sup>0</sup> and <sup>3</sup>H<sup>+</sup>transport behaviors. <sup>3</sup>H<sup>+</sup> diffuses 2-4 times slower than <sup>3</sup>H<sup>0</sup>, which can be ascribed to hydrogen bonding and complexation in solution. This work helps explain varying experimental results and provides useful species transport data for designing hydrogen control systems for molten salts. </p>


Kerntechnik ◽  
2021 ◽  
Vol 86 (2) ◽  
pp. 152-163
Author(s):  
T.-C. Wang ◽  
M. Lee

Abstract In the present study, a methodology is developed to quantify the uncertainties of special model parameters of the integral severe accident analysis code MAAP5. Here, the in-vessel hydrogen production during a core melt accident for Lungmen Nuclear Power Station of Taiwan Power Company, an advanced boiling water reactor, is analyzed. Sensitivity studies are performed to identify those parameters with an impact on the output parameter. For this, multiple calculations of MAAP5 are performed with input combinations generated from Latin Hypercube Sampling (LHS). The results are analyzed to determine the 95th percentile with 95% confidence level value of the amount of in-vessel hydrogen production. The calculations show that the default model options for IOXIDE and FGBYPA are recommended. The Pearson Correlation Coefficient (PCC) was used to determine the impact of model parameters on the target output parameters and showed that the three parameters TCLMAX, FCO, FOXBJ are highly influencing the in-vessel hydrogen generation. Suggestions of values of these three parameters are given.


2021 ◽  
Vol 2083 (2) ◽  
pp. 022020
Author(s):  
Jiahuan Yu ◽  
Xiaofeng Zhang

Abstract With the development of the nuclear energy industry and the increasing demand for environmental protection, the impact of nuclear power plant radiation on the environment has gradually entered the public view. This article combs the nuclear power plant radiation environmental management systems of several countries, takes the domestic and foreign management of radioactive effluent discharge from nuclear power plants as a starting point, analyses and compares the laws and standards related to radioactive effluents from nuclear power plants in France, the United States, China, and South Korea. In this paper, the management improvement of radioactive effluent discharge system of Chinese nuclear power plants has been discussed.


2021 ◽  
Vol 2021 (11) ◽  
Author(s):  
◽  
Angel Abusleme ◽  
Thomas Adam ◽  
Shakeel Ahmad ◽  
Rizwan Ahmed ◽  
...  

Abstract JUNO is a massive liquid scintillator detector with a primary scientific goal of determining the neutrino mass ordering by studying the oscillated anti-neutrino flux coming from two nuclear power plants at 53 km distance. The expected signal anti-neutrino interaction rate is only 60 counts per day (cpd), therefore a careful control of the background sources due to radioactivity is critical. In particular, natural radioactivity present in all materials and in the environment represents a serious issue that could impair the sensitivity of the experiment if appropriate countermeasures were not foreseen. In this paper we discuss the background reduction strategies undertaken by the JUNO collaboration to reduce at minimum the impact of natural radioactivity. We describe our efforts for an optimized experimental design, a careful material screening and accurate detector production handling, and a constant control of the expected results through a meticulous Monte Carlo simulation program. We show that all these actions should allow us to keep the background count rate safely below the target value of 10 Hz (i.e. ∼1 cpd accidental background) in the default fiducial volume, above an energy threshold of 0.7 MeV.


Author(s):  
Sang-Nyung Kim ◽  
Sang-Gyu Lim

The safety injection (SI) nozzle of a 1000MWe-class Korean standard nuclear power plant (KSNP) is fitted with thermal sleeves (T/S) to alleviate thermal fatigue. Thermal sleeves in KSNP #3 & #4 in Yeonggwang (YG) & Ulchin (UC) are manufactured out of In-600 and fitted solidly without any problem, whereas KSNP #5 & #6 in the same nuclear power plants, also fitted with thermal sleeves made of In-690 for increased corrosion resistance, experienced a loosening of thermal sleeves in all reactors except KSNP YG #5-1A, resulting in significant loss of generation availability. An investigation into the cause of the loosening of the thermal sleeves only found out that the thermal sleeves were subject to severe vibration and rotation, failing to uncover the root cause and mechanism of the loosening. In an effort to identify the root cause of T/S loosening, three suspected causes were analyzed: (1) the impact force of flow on the T/S when the safety SI nozzle was in operation, (2) the differences between In-600 and In-690 in terms of physical and chemical properties (notably the thermal expansion coefficient), and (3) the positioning error after explosive expansion of the T/S as well as the asymmetric expansion of T/S. It was confirmed that none of the three suspected causes could be considered as the root cause. However, after reviewing design changes applied to the Palo Verde nuclear plant predating KSNP YG #3 & #4 to KSNP #5 & #6, it was realized that the second design modification (in terms of groove depth & material) had required an additional explosive energy by 150% in aggregate, but the amount of gunpowder and the explosive expansion method were the same as before, resulting in insufficient explosive force that led to poor thermal sleeve expansion. T/S measurement data and rubbing copies also support this conclusion. In addition, it is our judgment that the acceptance criteria applicable to T/S fitting was not strict enough, failing to single out thermal sleeves that were not expanded sufficiently. Furthermore, the T/S loosening was also attributable to lenient quality control before and after fitting the T/S that resulted in significant uncertainty. Lastly, in a flow-induced vibration test planned to account for the flow mechanism that had a direct impact upon the loosening of the thermal sleeves that were not fitted completely, it was discovered that the T/S loosening was attributable to RCS main flow. In addition, it was proven theoretically that the rotation of the T/S was induced by vibration.


Author(s):  
Riccardo Costantini

The author develops an endogenous growth framework in which energy production is based on a learning by doing technology exploiting renewable reproducible capital and nuclear power plants. Consumption activities generates radioactive waste according to an exogenous factor reflecting the economy energy mix, while an abatement technology, reducing the impact of solid waste accumulation on welfare, is explicitly taken into account. Differently from traditional growth and environmental literature, the author includes an explicit preference for the technology mix by postulating a non separable utility in consumption, radioactive waste and stock of renewable capital. Within this framework the author derives conditions on preferences under which sustained growth is attainable without imposing, ex ante, neither compensation nor a distaste effect characterizing utility. Finally, introducing simplifying assumptions on the preference relation, an investigation of the dynamic property of the equilibrium is provided. The results obtained suggest a high complementarity of renewable capital and nuclear technology exploitation in determining potential long run growth.


The Death of Industrial Civilization explains how the contemporary ecological crisis within industrial society is caused by the values inherent in unlimited economic growth and competitive materialism. It demonstrates the central role and importance of electricity, and what policy makers need to do in order to ensure that current and future systems remain reliable even as they are transformed by the rise of clean energy technologies. The novel COVID19 pandemic has created an unprecedented global health and economic crisis. The result of such a scenario is that energy demand contracts by 6%, the largest in 70 years in percentage terms and the largest ever in absolute terms. The impact of Covid19 on energy demand in 2020 would be more than seven times larger than the impact of the 2008 financial crisis on global energy demand and this is what the Olduvai theory is defined by e=energy production/population. It states that the life expectancy of Industrial Civilization is less than or equal to 100 years.


2021 ◽  
pp. 309-314
Author(s):  
Irma Martyn ◽  
Yaroslav Petrov ◽  
Sergey Stepanov ◽  
Artem Sidorenko

2020 ◽  
Vol 239 ◽  
pp. 19005
Author(s):  
Zhang Wenxin ◽  
Qiang shenglong ◽  
Yin qiang ◽  
Cui Xiantao

Neutron cross section data is the basis of nuclear reactor physical calculation and has a decisive influence on the accuracy of calculation results. AFA3Gassemble is widely used in nuclear power plants. CENACE is an ACE format multiple-temperature continuous energy cross section library that developed by China Nuclear Data Centre. In this paper, we calculated the AFA3G assemble by RMC.We respectively used ENDF6.8/, ENDF/7 and CENACE data for calculation. The impact of nuclear data on RMC calculation is studied by comparing the results of different nuclear data.


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