scholarly journals Emerging investigator series: A Holistic Approach to Multicomponent EXAFS: Sr and Cs Complexation in Clayey Soils

2021 ◽  
Author(s):  
Pieter Bots ◽  
M. Josick Comarmond ◽  
Timothy E. Payne ◽  
Katharina Gückel ◽  
Rebecca J. Lunn ◽  
...  
Keyword(s):  
Fission Products ◽  
Holistic Approach ◽  
Clayey Soils ◽  
Nuclear Accidents

Strontium and caesium are fission products of concern at many nuclear legacy sites and Cs is additionally a significant consideration at sites in the aftermath of nuclear accidents and incidents....

scholarly journals Correction: Emerging investigator series: a holistic approach to multicomponent EXAFS: Sr and Cs complexation in clayey soils

2021 ◽  
Author(s):  
Pieter Bots ◽  
M. Josick Comarmond ◽  
Timothy E. Payne ◽  
Katharina Gückel ◽  
Rebecca J. Lunn ◽  
...  
Keyword(s):  
Holistic Approach ◽  
Clayey Soils

Correction for ‘Emerging investigator series: a holistic approach to multicomponent EXAFS: Sr and Cs complexation in clayey soils’ by Pieter Bots et al., Environ. Sci.: Processes Impacts, 2021, DOI: 10.1039/D1EM00121C.

Implementation of A Gibbs Energy Minimizer In A Fission-Product Release Computer Program

2013 ◽  
Vol 2 (1) ◽  
pp. 39-48
Author(s):  
D.H. Barber
Keyword(s):  
Computer Program ◽  
Fission Product ◽  
Nuclear Physics ◽  
Noble Gas ◽  
Safety Margin ◽  
Fission Products ◽  
Nuclear Accidents ◽  
The Public ◽  
Product Release ◽  
Core Cooling

SOURCE 2.0 is the Canadian computer program for calculating fractional release of fission products from the UO2 fuel matrix. In nuclear accidents, fission-product release from fuel is one of the physical steps required before radiation dose from fission products can affect the public. Fission-product release calculations are a step in the analysis path to calculating dose consequences to the public from postulated nuclear accidents. SOURCE 2.0 contains a 1997 model of fission-product vaporization by B.J. Corse et al. based on lookup tables generated with the FACT computer program. That model was tractable on computers of that day. However, the understanding of fuel thermochemistry has advanced since that time. Additionally, computational resources have significantly improved since the time of the development of the Corse model and now allow incorporation of the more-rigorous thermodynamic treatment. Combining the newer Royal Military College of Canada (RMC) thermodynamic model of irradiated uranium dioxide fuel, a new model for fission-product vaporization from the fuel surface, a commercial user-callable thermodynamics subroutine library (ChemApp), an updated nuclide list, and updated nuclear physics data, a prototype computer program based on SOURCE IST 2.0P11 has been created that performs thermodynamic calculations internally. The resulting prototype code (with updated and revised data) provides estimates of 140La releases that are in better agreement with experiments than the original code version and data. The improvement can be quantified by a reduction in the mean difference between experimental and calculated release fractions from 0.70 to 0.07. 140La is taken to be representative of “low-volatile” fission products. To ensure that the existing acceptable performance for noble gases and volatile fission products is not adversely affected by the changes, comparisons were also made for a representative noble gas, 85Kr, and a representative volatile fission-product, 134Cs. These nuclides have the largest dataset in the SOURCE 2.0 validation test suite. This improvement provides increased confidence in the safety margin for equipment qualification in Loss-of-Coolant Accidents with Loss of Emergency Core Cooling.

Influence of fission products on ruthenium oxidation and transport in air ingress nuclear accidents

2010 ◽  
Vol 396 (2-3) ◽  
pp. 208-217 ◽  
Author(s):  
N. Vér ◽  
L. Matus ◽  
M. Kunstár ◽  
J. Osán ◽  
Z. Hózer ◽  
...  
Keyword(s):  
Fission Products ◽  
Nuclear Accidents ◽  
Ruthenium Oxidation ◽  
Air Ingress

scholarly journals Experimental Investigation of Iodine Removal in a Submerged Venturi Scrubber

2021 ◽  
Vol 12 (1) ◽  
pp. 38
Author(s):  
Jawaria Ahad ◽  
Amjad Farooq ◽  
Masroor Ahmad ◽  
Khalid Waheed ◽  
Kamran Rasheed Qureshi ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Nuclear Power ◽  
Fission Products ◽  
Severe Accident ◽  
Operating Parameters ◽  
Nuclear Accidents ◽  
Sodium Thiosulphate ◽  
Venturi Scrubber ◽  
Vis Spectroscopy ◽  
Accident Scenarios

Severe nuclear accidents can cause over-pressurization and serious damage to the containment of a nuclear power plant, which can result in the release of radioactivity into the environment. Filtered containment venting systems are a nuclear safety system that is designed to control over-pressurization and prevent radioactive fission products from spreading into the environment in the case of a severe accident. Iodine is one of the most harmful products among this list of fissionable products, as it can cause thyroid cancer. The removal of iodine is very important in order to ensure the safety of people and the environment. Thus, an indigenous lab scale setup of this system was developed at PIEAS to conduct research on iodine removal. It is comprised of a compressor for replicating high-pressure accident scenarios, a heater to keep iodine in a vapor form, a dosing pump for the injection of iodine, and a venturi scrubber, submerged in the scrubbing column, containing a solution of 0.2% sodium thiosulphate and 0.5% sodium hydroxide. Inlet and outlet samples were trapped in 0.1 M KOH solution and analyzed via UV-VIS spectroscopy. Operating parameters play an important role in the working of a venturi scrubber. The throat velocity was varied to determine its influence on the removal efficiency of iodine. An increase in removal efficiency was observed with an increase in throat velocity. A removal efficiency of >99% was achieved, which fulfilled the requirements for FCVS.

Nuclear Processes Related to the Ap Stars and the Heaviest Chemical Elements

1976 ◽  
Vol 32 ◽  
pp. 169-182
Author(s):  
B. Kuchowicz
Keyword(s):  
Nuclear Physics ◽  
Nuclear Reactions ◽  
Chemical Elements ◽  
Fission Products ◽  
Abundance Pattern ◽  
Isotopic Shifts ◽  
Processed Material ◽  
R Process ◽  
Ap Stars ◽  
Nuclear Processes

SummaryIsotopic shifts in the lines of the heavy elements in Ap stars, and the characteristic abundance pattern of these elements point to the fact that we are observing mainly the products of rapid neutron capture. The peculiar A stars may be treated as the show windows for the products of a recent r-process in their neighbourhood. This process can be located either in Supernovae exploding in a binary system in which the present Ap stars were secondaries, or in Supernovae exploding in young clusters. Secondary processes, e.g. spontaneous fission or nuclear reactions with highly abundant fission products, may occur further with the r-processed material in the surface of the Ap stars. The role of these stars to the theory of nucleosynthesis and to nuclear physics is emphasized.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

TEM studies of amorphization processes and amorphous structures

1988 ◽  
Vol 46 ◽  
pp. 448-449
Author(s):  
T. E. Mitchell ◽  
R. B. Schwarz
Keyword(s):  
Amorphous Materials ◽  
Fission Products ◽  
Rapid Quenching ◽  
Surface Films ◽  
List Type ◽  
Oxide Glasses ◽  
Crystalline Materials ◽  
Amorphous Structures ◽  
Amorphous Surface ◽  
Interfacial Films

Traditional oxide glasses occur naturally as obsidian and can be made easily by suitable cooling histories. In the past 30 years, a variety of techniques have been discovered which amorphize normally crystalline materials such as metals. These include [1-3]:Rapid quenching from the vapor phase.Rapid quenching from the liquid phase.Electrodeposition of certain alloys, e.g. Fe-P.Oxidation of crystals to produce amorphous surface oxide layers.Interdiffusion of two pure crystalline metals.Hydrogen-induced vitrification of an intermetal1ic.Mechanical alloying and ball-milling of intermetal lie compounds.Irradiation processes of all kinds using ions, electrons, neutrons, and fission products.We offer here some general comments on the use of TEM to study these materials and give some particular examples of such studies.Thin specimens can be prepared from bulk homogeneous materials in the usual way. Most often, however, amorphous materials are in the form of surface films or interfacial films with different chemistry from the substrates.

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