Oxidation of ruthenium oxide deposits by ozone

2008 ◽  
Vol 96 (6) ◽  
Author(s):  
Christian Mun ◽  
L. Cantrel ◽  
Charles Madic
Keyword(s):  
Ruthenium Oxide ◽  
Severe Accident ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor

SummaryDuring a hypothetical severe accident on a nuclear Pressurized Water Reactor (PWR), the formation of highly radiotoxic RuO

scholarly journals Contribution to the study of fission products release from nuclear fuels in severe accident conditions: effect of the pO2 on Cs, Mo and Ba speciation

2020 ◽  
Vol 6 ◽  
pp. 2 ◽  
Author(s):  
Claire Le Gall ◽  
Fabienne Audubert ◽  
Jacques Léchelle ◽  
Yves Pontillon ◽  
Jean-Louis Hazemann
Keyword(s):  
Oxygen Potential ◽  
Fission Products ◽  
Severe Accident ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
Mox Fuel ◽  
Chemical Behaviour ◽  
Accident Conditions ◽  
The Impact

The objective of this work is to experimentally investigate the effect of the oxygen potential on the fuel and FP chemical behaviour in conditions representative of a severe accident. More specifically, the speciation of Cs, Mo and Ba is investigated. These three highly reactive FP are among the most abundant elements produced through 235U and 239Pu thermal fission and may have a significant impact on human health and environmental contamination in case of a light water reactor severe accident. This work has set out to contribute to the following three fields: providing experimental data on Pressurized Water Reactor (PWR) MOX fuel behaviour submitted to severe accident conditions and related FP speciation; going further in the understanding of FP speciation mechanisms at different stages of a severe accident; developing a method to study volatile FP behaviour, involving the investigation of SIMFuel samples manufactured at low temperature through SPS. In this paper, a focus is made on the impact of the oxygen potential towards the interaction between irradiated MOX fuels and the cladding, the interaction between Mo and Ba under oxidizing conditions and the assessment of the oxygen potential during sintering.

Numerical Investigation on the Gas Filling Process of Hydrogen-Air-Steam Mixtures in a Semi-Confined Experimental Pipe

2017 ◽  
Author(s):  
Min Li ◽  
Youyou Xu ◽  
Xiaojian Wen ◽  
Songlin Liu ◽  
Guangnan Luo
Keyword(s):  
Severe Accident ◽  
Blockage Ratio ◽  
Gas Composition ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
Safety Research ◽  
Filling Time ◽  
Time Required ◽  
Hydrogen Safety

Hydrogen gathering in the containment may occur followed by a severe accident in a nuclear power plant. A flammable mixture can be formed when hydrogen is mixed with air. The ignition of the gas mixture could threaten the integrity of the containment. In order to provide technology base and experiment data for optimization of hydrogen safety technology of Chinese advanced pressurized water reactor CAP1400, a major project regarding hydrogen safety research of pressurized water reactor containment is underway. As an important part of the project, an experimental facility (A4Q-DH) for the study of hydrogen combustion will be built. Gas displacement method is used to filling the premixed hydrogen-air-steam mixtures into the experimental pipe. Flow behaviors of the gases in the pipe are complicated because fluid flow can be disturbed by the built-in obstacles and gas density can be changed with variation of gas composition concentration. Therefore, it is necessary to evaluate the effectiveness of the gas filling method. In this paper, gas filling processes for the experimental pipe with different obstacles and gas composition concentrations were simulated using computational fluid dynamics software ANSYS Fluent. The results indicated that hydrogen-air-steam mixtures can be uniformly distributed in the experimental pipe within tens of seconds. The obstacles with modest blockage ratio in the pipe are conducive to shorten the required gas filling time. The hindering effect of annular obstacles is greater than the one of circular and square obstacles. The time required for air to achieve uniformly distribution increases with the increase of the inlet concentration of steam and hydrogen. However, the time required for hydrogen and steam to be evenly distributed in the pipe are relatively close regardless of the shape and blockage ratio of obstacle and the inlet gas concentration.

scholarly journals Unstable Crack Propagation Under Severe Accident Scenario Conditions in a Pressurized Water Reactor

2009 ◽  
Author(s):  
Nicolas Tardif ◽  
Michel Coret ◽  
Alain Combesure
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Internal Pressure ◽  
Severe Accident ◽  
Pressurized Water Reactor ◽  
Crack Initiation And Propagation ◽  
Pressurized Water ◽  
Water Reactor ◽  
Initiation And Propagation ◽  
Vessel Bottom

In the case of a severe accident scenario of a pressurized water reactor which includes cracking of the vessel bottom head, it is crucial to predict the leak rate and hence the crack size for the ex-vessel accident management. We present an experimental framework to analyze the crack propagation under such severe conditions for different 16MND5 French nuclear steel grades. An original experimental setup has been designed in order to perform bi-axial tests (tensile load independent of internal pressure) at high temperatures (1180K – 1280K) on tubular test specimens. The temperature loading and the mechanical loading can be set to reproduce the stress distribution of the hemispherical vessel bottom head submitted to an internal pressure. Moreover, the test was designed to be easily transposable to the real structure in terms of crack propagation and depressurization thanks to an energy based scaling methodology. We observed the crack initiation and propagation with two high speed digital cameras. Force, internal pressure, displacement and temperature fields were also measured and synchronized with the optical measurements. The different creep stages are observed and characterized. The crack propagation and opening history have been measured. During crack initiation and propagation stages, the depressurization can be correlated with the crack geometry. Finally, the setup has been designed in order to validate future numerical analysis.

The CANDLE burnup strategy applied to small modular pressurized water reactor loading with fully ceramic microencapsulated fuel

Kerntechnik ◽  
2022 ◽  
Vol 0 (0) ◽  
Author(s):  
Jinfeng Huang ◽  
Jiaming Jiang
Keyword(s):  
Equilibrium State ◽  
Power Plants ◽  
Reactor Core ◽  
Severe Accident ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Water Reactor ◽  
The Core ◽  
Core Height ◽  
Optimization Schemes

Abstract For post-Fukushima nuclear power plants, there has been interested in accident-tolerant fuel (ATF) since it has better tolerant in the event of a severe accident. The fully ceramic microencapsulated (FCM) fuel is one kind of the ATF materials. In this study, the small modular pressurized water reactor (PWR) loading with FCM fuels was investigated, and the modified Constant Axial shape of Neutron flux, nuclide number densities and power shape During Life of Energy producing reactor (CANDLE) burnup strategy was successfully applied to such compact reactor core. To obtain ideal CANDLE shape, it’s necessary to set the infinity or enough length of the core height, but that is impossible for small compact core setting infinity or enough length of the core height. Due to the compact and finite core, the equilibrium state can only be maintained short periods and is not obvious, other than infinitely long active core to reach the long equilibrium state for ideal CANDLE. Consequently, the modified CANDLE shape would be presented. The approximate characteristics of CANDLE burnup are observed in the finite and compact core, and the power density and fuel burnup are selected as main characteristic of modified CANDLE burnup. In this study, firstly, lots of optimization schemes were discussed, and one of optimization schemes was chosen at last to demonstrate the modified CANDLE burnup strategy. Secondly, for chosen compact small rector core, the modified CANDLE burnup strategy is applied and presented. Consequently, the new characteristics of this reactor core can be discovered both in ignition region and in fertile region. The results show that application of CANDLE burnup strategy to small modular PWR loading with FCM fuels suppresses the excess reactivity effectively and reduces the risk of small PWR reactivity-induced accidents during the whole core life, which makes the reactor control more safety and simple.

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