Effects of some level density models and γ-ray strength functions on production cross-section calculations of 16,18O and 24,26Mg radioisotopes

Oxygen and magnesium isotopes can be used in nuclear reactor materials as cooling, shielding, coating, electronics etc. They can also occur through nuclear reactions during the reactor operation. The exposure of high energy gamma can change the material and its properties, and hence its objective of selection may not remain satisfied. Thus, it is required to study the cross section of different reactions on nuclear reactor materials to understand their sustainability for the properties, for which they are chosen. In the scope of this study, theoretically, different level density model calculations and γ-ray strength functions have been performed for (γ, p) reaction for 16,18O and 24,26Mg nuclei using TALYS 1.9 and EMPI˙RE 3.2.2 codes. Also, semi empirical (γ, p) formula by Tel et al., have been calculated and compared with all results. The effect of different level density models defined in these codes on gamma strength has been studied. Finally, the consistency of these obtained data with EXFOR data have been investigated.

Effect of Phosphine on Coke Formation during Steam Cracking of Propane

In conventional steam cracking feedstocks, contaminants such as sulfur, phosphine, and heavy metal components, present in trace levels, are believed to affect coke formation on high temperature alloys. To gain an understanding of the role of phosphine coking rates on 25/35, CrNi and Al-containing reactor materials were determined in a plug flow reactor during cracking of a propane feedstock doped with ppb levels of PH3 in the presence of DMDS. The presence of phosphine decreased the asymptotic coking rates by more than 20%, while it had a smaller influence on the catalytic coking rate. The coking rate was more severely reduced for the 25/35 CrNi alloy in comparison to the Al-containing alloy. The ppm levels of phosphine did not affect the olefin yields nor the production of undesired carbon monoxide. The morphology of the coked alloys were studied using an off-line Scanning Electron Microscope with Energy Dispersive X-ray detector (SEM with EDX) images of coked coupons. Two types of coke morphology are observed, i.e., filamentous coke with DMDS as an additive and globular coke in the presence of phosphine. The effect of phosphine on the material has a positive impact on the oxide scale homogeneity of 25/35 CrNi alloy, whereas the Al-containing alloy remained unchanged.

Plasma Torch Working Gas Selection Rationale for the Production Technology of Ultrapure White Corundum

This paper presents the results of one of the stages in the development of a plasma technology for producing ultrapure white corundum. This technology involves the melting of alumina in a reactor under the influence of plasma. To create the plasma, a plasma-forming gas is needed; in other words, the plasma torch working gas. To implement this technology, the chosen working gas must meet certain requirements. More precisely: 1) the gas should not form explosive or toxic compounds either with the reactor materials or the material of the electrodes; 2) it should not accelerate their erosion. An important requirement that a plasma torch working gas must have is minimal interaction with surrounding substances, even at high temperatures. This will reduce the likelihood of contamination of the melt with materials of the reactor itself. We consider using hydrogen, nitrogen and argon. Taking into account the requirements for the working gas, we opt for the mixture of nitrogen and argon at a concentration of 25÷30% N2 – 70÷75% Ar. Keywords: plasma torch, corundum, plasma technology, ultrapure materials

Cladding Profilometry Analysis of Experimental Breeder Reactor-II Metallic Fuel Pins with HT9, D9, and SS316 Cladding

BISON finite element method fuel performance simulations were conducted using an existing automated process that couples the Fuels Irradiation & Physics Database (FIPD) and the Integral Fast Reactor Materials Information System database by writing input files and comparing the BISON output to post-irradiation fuel pin profilometry measurements contained within the databases. The importance of this work is to demonstrate the ability to benchmark fuel performance metallic fuel models within BISON using Experimental Breeder Reactor-II fuel pin data for a number of similar pins, while building off previous modeling efforts. Changes to the generic BISON input file include implementing pin specific axial power and flux profiles, pin specific fluences, frictional contact, and irradiation-induced volumetric swelling models for cladding. A statistical analysis of irradiation-induced volumetric swelling models for HT9, D9, and SS316 was performed for experiments X421/X421A, X441/X441A, and X486. Between these three experiments, there were 174 post-irradiation examination (PIE) profilometries used for validating the swelling models presented using a standard error of the estimate (SEE) method. Implementation of the volumetric swelling models for D9 and SS316 claddings was found to have a significant impact on the BISON profilometry simulated, where HT9 clad pins had an insignificant change due to low fluence values. BISON profilometry simulated for HT9, D9, and SS316 fuel pins agreed with PIE profilometry measurements, with assembly SEE values being 4.4 × 10−3 for X421A, 2.0 × 10−3 for X441A, and 2.8 × 10−3 for X486. D9 clad pins in X421/X421A had the highest SEE values, which is due to the BISON simulated profilometry being shifted axially. While this work accomplished its purpose to demonstrate the modeling of multiple fuel pins from the databases to help validate models, the results suggest that the continued development of metallic fuel models is necessary for qualifying new metallic fuel systems to better capture some physical performance phenomena, such as the hot pressing of U-Pu-Zr and the fuel cladding chemical interaction.