Absorption of iodine from aqueous solutions on nuclear reactors alloys

2001 ◽  
Vol 89 (2) ◽  
Author(s):  
B. Bayri ◽  
R. Rosset ◽  
K. El Kacemi
Keyword(s):  
Acidic Medium ◽  
Nuclear Reactor ◽  
Nuclear Reactors ◽  
Molecular Iodine ◽  
304 Stainless Steel ◽  
Basic Medium ◽  
Iodide Ions ◽  
Inconel 600 ◽  
Influence Of Ph ◽  
Iodine Retention

Iodide ions IIodide and iodate anions are not absorbed on the three considered alloys and contribute only for a negligible quantity to iodine retention on the nuclear reactors materials. Molecular iodine is absorbed according to:304 stainless steel < Zircaloy < Inconel 600.Influence of pH has been studied: absorption increases in acidic medium and decreases in basic medium. Molecular iodine absorption increases with temperature.Phenomenons which occur with iodine during the cold shutdown of a nuclear reactor and during its restart are discussed from the point of vue of iodine volatilization risk.

Japan's Post-Fukushima Energy Politics

2015 ◽  
Vol 07 (02) ◽  
pp. 109-116
Author(s):  
Tai Wei LIM
Keyword(s):  
Democratic Party ◽  
Nuclear Reactor ◽  
Prime Minister ◽  
Nuclear Reactors ◽  
Liberal Democratic Party ◽  
The Political ◽  
Political Arena ◽  
Liberal Democratic ◽  
Energy Politics ◽  
Gubernatorial Election

A 2011 earthquake damaged the Fukushima nuclear reactor and provided a galvanising point for anti-nuclear resistance groups in Japan. Their public cause slowly faded from the political arena after the Democratic Party of Japan fell out of power and anti-nuclear politicians lost the 2014 Tokyo gubernatorial election. The current Liberal Democratic Party Prime Minister Abe holds a pro-nuclear position and urges the reactivation of Japan's nuclear reactors after all safeguards have been satisfied.

Exploring the Use of Alumina Nanofluid as Emergency Coolant for Nuclear Fuel Bundle

2018 ◽  
Vol 11 (2) ◽  
Author(s):  
A. S. Chinchole ◽  
Arnab Dasgupta ◽  
P. P. Kulkarni ◽  
D. K. Chandraker ◽  
A. K. Nayak
Keyword(s):  
Heat Transfer ◽  
Nuclear Fuel ◽  
Nuclear Reactor ◽  
Cooling System ◽  
Nuclear Reactors ◽  
Electrical Heating ◽  
High Dose ◽  
Potential Candidate ◽  
Alumina Nanofluid ◽  
Core Cooling

Abstract Nanofluids are suspensions of nanosized particles in any base fluid that show significant enhancement of their heat transfer properties at modest nanoparticle concentrations. Due to enhanced thermal properties at low nanoparticle concentration, it is a potential candidate for utilization in nuclear heat transfer applications. In the last decade, there have been few studies which indicate possible advantages of using nanofluids as a coolant in nuclear reactors during normal as well as accidental conditions. In continuation with these studies, the utilization of nanofluids as a viable candidate for emergency core cooling in nuclear reactors is explored in this paper by carrying out experiments in a scaled facility. The experiments carried out mainly focus on quenching behavior of a simulated nuclear fuel rod bundle by using 1% Alumina nanofluid as a coolant in emergency core cooling system (ECCS). In addition, its performance is compared with water. In the experiments, nuclear decay heat (from 1.5% to 2.6% reactor full power) is simulated through electrical heating. The present experiments show that, from heat transfer point of view, alumina nanofluids have a definite advantage over water as coolant for ECCS. Additionally, to assess the suitability of using nanofluids in reactors, their stability was investigated in radiation field. Our tests showed good stability even after very high dose of radiation, indicating the feasibility of their possible use in nuclear reactor heat transfer systems.

The reduction of I2 by H2O2 in aqueous solution

2001 ◽  
Vol 79 (3) ◽  
pp. 304-311 ◽  
Author(s):  
J M Ball ◽  
J B Hnatiw
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Nuclear Reactor ◽  
Ph Dependence ◽  
Radiolysis Product ◽  
Molecular Iodine ◽  
Water Radiolysis ◽  
Reactor Accident ◽  
Rate Law ◽  
Accident Conditions

The reduction of I2 by hydrogen peroxide, a primary water radiolysis product, has been identified as a key reaction that would influence iodine volatility in nuclear reactor accident conditions (1–3). Although there have been a number of studies of the reduction of I2, there exists a great degree of controversy regarding the intermediates involved, the effect of buffers, and the general rate law (1–9). Because the rates and the mechanism of this reaction are important in predicting the pH dependence of iodine behaviour in reactor containment building after a postulated reactor accident, we have undertaken a kinetic study of I2 reduction by H2O2 in aqueous solution over a pH range of 6–9. The experiments were performed using stopped-flow instrumentation and monitoring the decay of I–3 spectrophotometrically. The effects of buffer catalysis have been examined by comparison of kinetic data obtained in sodium barbital (5,5-diethylbarbituric acid), disodium citrate, and disodium hydrogen phosphate buffers. The effect of buffers, combined with the complex acid dependence of the rate law, explains many of the discrepancies reported in earlier literature.Key words: hydrogen peroxide, molecular iodine, kinetics, iodine volatility.

Molecular-Iodine-Promoted Synthesis of Dihydrobenzofuran-3,3-dicarbonitriles through a Novel Rearrangement

Synlett ◽  
2019 ◽  
Vol 30 (03) ◽  
pp. 293-298
Author(s):  
Nagaraju Medishetti ◽  
Ashok Kale ◽  
Jagadeesh Nanubolu ◽  
Krishnaiah Atmakur
Keyword(s):  
Molecular Iodine ◽  
Basic Medium ◽  
Reaction Conditions ◽  
Simple Reaction

The title compounds were synthesized from 5,5-dimethyl­cyclohexane-1,3-dione, benzaldehyde, and malononitrile promoted by molecular iodine in basic medium via 2-amino-7,7-dimethyl-5-oxo-4-phenyl-5,6,7,8-tetrahydro-4H-chromene-3-carbonitrile, by a novel protocol. The protocol involves a novel rearrangement in which the 4H-chromene fragment dissociates to a cyclopropane moiety and rearranges to the five-membered compound 6,6-dimethyl-4-oxo-2-phenyl-4,5,6,7-tetrahydrobenzofuran-3,3(2H)-dicarbonitrile. Simple reaction conditions, excellent yields, and high compatibility are the advantages of this protocol.

Thermal Aspects of Uranium Carbide and Uranium Dicarbide Fuels in Supercritical Water-Cooled Nuclear Reactors

2010 ◽  
Vol 133 (2) ◽  
Author(s):  
Lisa Grande ◽  
Bryan Villamere ◽  
Leyland Allison ◽  
Sally Mikhael ◽  
Adrianexy Rodriguez-Prado ◽  
...  
Keyword(s):  
Supercritical Water ◽  
Thermal Efficiency ◽  
Alternative Fuels ◽  
Nuclear Reactors ◽  
Operating Parameters ◽  
Inconel 600 ◽  
Uranium Carbide ◽  
Centerline Temperature ◽  
Sheath Material ◽  
Thermal Conductivities

Supercritical water-cooled nuclear reactors (SCWRs) are a Generation IV reactor concept. SCWRs will use a light-water coolant at operating parameters set above the critical point of water (22.1 MPa and 374°C). One reason for moving from current Nuclear Power Plant (NPP) designs to SCW NPP designs is to increase the thermal efficiency. The thermal efficiency of existing NPPs is between 30% and 35% compared with 45% and 50% of supercritical water (SCW) NPPs. Another benefit of SCWRs is the use of a simplified flow circuit, in which steam generators, steam dryers, steam separators, etc. can be eliminated. Canada is in the process of conceptualizing a pressure tube (PT) type SCWR. This concept refers to a 1200-MWel PT-type reactor. Coolant operating parameters are as follows: a pressure of 25 MPa, a channel inlet temperature of 350°C, and an outlet temperature of 625°C. The sheath material and nuclear fuel must be able to withstand these extreme conditions. In general, the primary choice for the sheath is a zirconium alloy and the fuel is an enriched uranium dioxide (UO2). The sheath-temperature design limit is 850°C, and the industry accepted limit for the fuel centerline temperature is 1850°C. Previous studies have shown that the maximum fuel centerline temperature of a UO2 pellet might exceed this industry accepted limit at SCWR conditions. Therefore, alternative fuels with higher thermal conductivities need to be investigated for SCWR use. Uranium carbide (UC), uranium nitride (UN), and uranium dicarbide (UC2) are excellent fuel choices as they all have higher thermal conductivities compared with conventional nuclear fuels such as UO2, mixed oxides (MOX), and thoria (ThO2). Inconel-600 has been selected as the sheath material due its high corrosion resistance and high yield strength in aggressive supercritical water (SCW) at high-temperatures. This paper presents the thermalhydraulics calculations of a generic PT-type SCWR fuel channel with a 43-element Inconel-600 bundle with UC and UC2 fuels. The bulk-fluid, sheath and fuel centerline temperature profiles, together with a heat transfer coefficient profile, were calculated for a generic PT-type SCWR fuel-bundle string. Fuel bundles with UC and UC2 fuels with various axial heat flux profiles (AHFPs) are acceptable since they do not exceed the sheath-temperature design limit of 850°C, and the industry accepted limit for the fuel centerline temperature of 1850°C. The most desirable case in terms of the lowest fuel centerline temperature is the UC fuel with the upstream-skewed cosine AHFP. In this case, the fuel centerline temperature does not exceed even the sheath-temperature design limit of 850°C.

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