CHEMICAL EFFECTS OF THE (n,r) ACTIVATION OF BROMINE IN THE ALKYL BROMIDES: THE HALOMETHANES

1961 ◽  
Vol 39 (1) ◽  
pp. 121-130 ◽  
Author(s):  
W. E. Harris
Keyword(s):  
Carbon Tetrachloride ◽  
Neutron Flux ◽  
Neutron Irradiation ◽  
Hot Spot ◽  
Thermal Reactions ◽  
Chemical Effects ◽  
Alkyl Bromides ◽  
Organic Products

Techniques for studying the chemical effects accompanying the neutron irradiation of the halomethanes with a neutron flux of only 108 neutrons per square centimeter per second are described. Results are presented from the irradiation of mixtures of bromine with the four bromomethanes and carbon tetrachloride. The formation of organic products which occur as the result of "hot", "hot-spot diffusive", and "thermal" reactions are discussed. The amounts of products resulting from these three types of reactions are estimated. Observations with respect to the formation of bromoethanes are also discussed.

THE CHEMICAL FATE OF RECOIL IODINE ATOMS IN IODINE–METHYL IODIDE SOLUTIONS

1964 ◽  
Vol 42 (12) ◽  
pp. 2684-2694
Author(s):  
N. V. Klassen ◽  
A. P. Baerg
Keyword(s):  
Methyl Iodide ◽  
Mole Fraction ◽  
Neutron Irradiation ◽  
Iodine Concentration ◽  
Thermal Reactions ◽  
Chemical Fate ◽  
Diffusion Controlled ◽  
Organic Products

The organic yield of recoil 126I, produced by the 14 MeV neutron irradiation of iodine–methyl iodide solutions, was examined over iodine concentrations from 0.34 mole fraction iodine to "pure" methyl iodide. By correcting for exchange between I2 and methyl iodide, the initial organic yield at very low iodine concentrations was found to be 57%. The time for one-half of the I2 to exchange with CH3I was found to decrease with decreasing iodine concentration. At all iodine concentrations the organic products containing 126I consisted mainly of CH3I and CH2I2. The formation of products is discussed in terms of thermal reactions, diffusion-controlled reactions in the spurs, and hot reactions.

The neutron irradiation effects on the temperature dependencies of the electrical conductivity of nanosilicon particles

2017 ◽  
Vol 31 (28) ◽  
pp. 1750257 ◽  
Author(s):  
Elchin Huseynov ◽  
Aydan Garibli
Keyword(s):  
Electrical Conductivity ◽  
Neutron Flux ◽  
Neutron Irradiation ◽  
Silicon Nanoparticles ◽  
Activation Energies ◽  
Radiation Defects ◽  
Irradiation Effects ◽  
Active Radiation ◽  
Before And After ◽  
Effects Of Temperature

The effects of temperature and neutron irradiation on the silicon nanoparticles have been studied at different frequencies. It has been defined that additional electro-active radiation defects occur in the silicon nanomaterial after neutron irradiation. Therefore, the change of neutron flux at the interval of [Formula: see text]–[Formula: see text] increases the conductivity of nanosilicon. Activation energies of the silicon nanoparticles were calculated for 10 different constant frequencies according to Arrhenius approach before and after neutron irradiation. The mechanism of electrical conductivity which explains results has been established.

Fast Neutron Irradiation Optimization of Thorium-Fueled SCWR Reactor Pressure Vessel

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Petra Pónya ◽  
Gyula Csom ◽  
Sándor Fehér
Keyword(s):  
Neutron Flux ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Pressure Vessel ◽  
Flow Direction ◽  
Reactor Pressure Vessel ◽  
Fast Neutron Flux ◽  
Inner Surface ◽  
Fast Neutron Irradiation ◽  
Reactor Pressure

Abstract Fast neutron irradiation causes embrittlement of the reactor pressure vessel (RPV) material; therefore, it may end operation life before design lifetime. Well-known method to recuperate crystal lattice dislocations is annealing. In the current version of thorium fueled supercritical water-cooled reactor (SCWR) design proposed by the Institute of Nuclear Technology at Budapest University of Technology and Economics (BME NTI), the supercritical fluid flows upward between the core barrel and the inner surface of the RPV thereby, the coolant would keep the RPV's temperature at ∼500 °C. This reverse coolant flow direction would decrease the embrittlement of RPV by constant annealing. To minimize the fast neutron flux increase, a relatively thin shielding connected to the inner surface of the barrel could be used. This presents fast neutron irradiation analysis, performed for different settings of the shielding to reduce fast neutron flux reaching the inner surface of RPV.

CHEMICAL EFFECTS OF THE (n, γ) ACTIVATION OF BROMINE IN THE ALKYL BROMIDES: ISOMERIZATION IN THE BROMOBUTANES1

1960 ◽  
Vol 64 (8) ◽  
pp. 1076-1078 ◽  
Author(s):  
W. H. McFadden ◽  
R. G. McIntosh ◽  
W. E. Harris
Keyword(s):  
Chemical Effects ◽  
Alkyl Bromides

A rapid, mild procedure for the preparation of alkyl chlorides and bromides

1968 ◽  
Vol 46 (1) ◽  
pp. 86-87 ◽  
Author(s):  
J. Hooz ◽  
S. S. H. Gilani
Keyword(s):  
Carbon Tetrachloride ◽  
High Yield ◽  
Carbon Tetrabromide ◽  
Alkyl Bromides ◽  
Reaction Proceeds

Primary and secondary alkyl chlorides have been conveniently prepared by the reaction of tri-n-octylphosphine with carbon tetrachloride solutions of the corresponding alcohols. This rapid, high yield reaction proceeds with inversion of configuration. By using carbon tetrabromide the method has been extended to the synthesis of alkyl bromides.

Effect of neutron irradiation on neat epoxy resin stability in shielding applications

2018 ◽  
Vol 25 (4) ◽  
pp. 725-729 ◽  
Author(s):  
Ruhollah Adeli ◽  
Seyed Pezhman Shirmardi ◽  
Hassan Abbasi ◽  
Seyed Javad Ahmadi
Keyword(s):  
Neutron Flux ◽  
Epoxy Resin ◽  
Neutron Irradiation ◽  
Irradiation Time ◽  
Light Element ◽  
Radiation Shielding ◽  
Neat Epoxy ◽  
Neutron Shielding ◽  
Tehran Research Reactor ◽  
Effective Neutron

Abstract Epoxy resin is a thermoset polymer and is one of the main candidates for radiation shielding application. In this investigation, carbon, hydrogen, and nitrogen analysis showed that the presence of the light element of nitrogen in cured epoxy could lead to more effective neutron shielding ability compared with physical curing. The effect of neutron irradiation of amine-cured epoxy was studied by infrared spectroscopy. Neat epoxy samples were irradiated at the core of the Tehran Research Reactor in the same neutron flux in the order of 1013 (neutron/cm2×s) at several radiation times (up to 12 h). The results indicated that neutron irradiation caused moderate changes in peak absorption locations of epoxy spectra. This result indicates that, in this neutron flux and irradiation time, the molecular structure of epoxy remains stable.

Influence cinétique et chimique d'alcènes sur la pyrolyse d'alcanes: mise au point et nouveaux résultats

1985 ◽  
Vol 63 (11) ◽  
pp. 2869-2884 ◽  
Author(s):  
Francis Billaud ◽  
François Baronnet ◽  
Michel Niclause
Keyword(s):  
Free Radicals ◽  
Double Bond ◽  
Thermal Cracking ◽  
Experimental Results ◽  
Heavy Oils ◽  
Double Bonds ◽  
Thermal Reactions ◽  
Chemical Effects ◽  
General Rules ◽  
Complex Models

On the basis of previously reported, as well as new, experimental results, a review is presented of the kinetic and chemical influences of alkenes on the pyrolysis of alkanes. The results confirm that the addition of free H• atoms to the double bonds of alkenes is not sufficient to explain their inhibiting influence on the pyrolysis of alkanes. On the contrary, our results show that the processes of addition can account for the chemical effects of added alkenes on the pyrolysis of alkanes, namely, the modifications brought to the nature and the ratio of the products formed during the reaction. The results presented here confirm that the addition of alkyl free radicals to the double bond of alkenes does not lead to important chemical effects. The previously reported experimental results (pyrolysis of ethane in the presence of ethylene or propene, the pyrolysis of 2,2-dimethylbutane in the presence of propene, isobutene, or two isopentenes), completed by our new results (pyrolysis of ethane in the presence of isobutene, pyrolysis of isobutane in the presence of ethylene, of propene, of trans-2-butene, or of 2-methyl-2-butene), can lead to very simple general rules, on the basis of which it is possible to explain the results and to predict the modifications (relating to the nature of the products and to their ratios) that will result from the addition of an alkene during the pyrolysis of an alkane at a temperature of 500 °C (773 K). Aside from their fundamental aspects, these observations and their mechanistic consequences could be useful for the preparation of models for these thermal reactions, especially for the simplification of complex models. These observations also explain certain facts observed in industry and can help in solving some of the problems associated with the thermal cracking of heavy oils.

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