International Journal of Nuclear Energy Science and Technology (8 papers in press)
Burn/breed: a wavelet-based nuclear fuel burnup and decay heat code
by Hesham Nasif
Abstract: Burn/breed is a code designed to aid in the analysis, prediction and optimisation of fuel burnup performance and decay heat calculation in a nuclear reactor. The code uses the output parameters generated by the Monte Carlo neutronics codes to determine the isotopic inventory as a function of time and power density. Burn/breed directly uses the neutron absorption tally/reaction information generated by Monte Carlo code for each nuclide of interest to determine the nuclide inventory. When the isotope inventories have been calculated for a specific reactor operation and cooling period, the decay heat can be derived. Beside the U-235 and Pu-239 decay chains, the code includes the U-233 decay chain to manage the possible scenarios for using thorium in a nuclear fuel cycle. This paper describes the theoretical basis of this code, and shows the results of the code for two test cases. The results show good agreement with other codes for the first test case and with the experimental results for the second test case.
Keywords: burn/breed; burnup; decay heat; nuclear reactor; Monte Carlo; isotopic inventory; wavelet; U-233 decay chain.
Radioprotective potential of some medicines used in Tabuk, Saudi Arabia, to minimise the effects of the ionising radiations
by M.I. Sayyed
Abstract: With increasing use of ionising radiations (in particular gamma-rays and X-rays) in medicine, many dangerous diseases may occur. Hence it is necessary to restrict and control exposure of human beings to these radiations. In this study, we have investigated the radioprotective effectiveness of some medications sold at community pharmacies in Tabuk, Saudi Arabia. The data were collected and recorded for 20 drugs commonly used for different medical purposes. In order to investigate the effectiveness of these radioprotectives in terms of absorption of low and high energy photons, the effective atomic numbers (Zeff) of ten drugs for total photon interaction in the energy range of 1 keV to 15MeV using WinXCom were calculated. In addition, by Geometric-Progression (G-P) method, the energy absorption (EABF) and exposure buildup factors (EBF) for incident photon energy 0.015 MeV to 15 MeV up to penetration depths of 40 mean free paths (mfp) were calculated for the other ten drugs. Among the selected compounds, Captopril and Cefixime have the maximum value of Zeff while the minimum EBF and EABF were found for Mesna, Cramastine, Thiotepa and Busflan; therefore, they are appealing as radioprotective compounds.
Keywords: Tabuk city; effective atomic number; buildup factor; G-P fitting; radioprotective.
The role of the breakup channel on the fusion reaction of light and weakly bound nuclei
by Fouad A. Majeed
Abstract: The effect of the breakup channel on fusion reactions of weakly bound systems by means of a semiclassical and full quantum mechanical approaches is discussed in this paper. The total fusion reaction cross-section and the fusion barrier distribution for the systems 4He+64Zn, 6Li +208Pb and 7Li +24Mg are calculated. The inclusion of the breakup channel enhances the calculations of the fusion cross-section markedly below the Coulomb barrier and hindrance above the Coulomb barrier in comparison with the experimental data. The semiclassical calculations agrees reasonably with the full quantum mechanical treatment, and they were able to reproduce the experimental data in detail for the total fusion reaction cross-section and the fusion barrier distribution.
Keywords: semiclassical treatment; quantum mechanical; breakup channel; weakly bound nuclei.
CFD analysis of thermalhydraulic behaviour of the high performance light water reactor fuel assembly
by Landy Castro, Rogelio Alfonso, Carlos Garcia, Jesus Rosales Garcia, Danny Sánchez
Abstract: The High Performance Light-Water Reactor (HPLWR) is the European version of the Super Critical Water-cooled Reactor (SCWR). The SCWR was proposed as a candidate of the fourth-generation reactors. In this paper, a thermal-hydraulic study of the HPLWR fuel assembly using Computational Fluid Dynamics (CFD) codes was carried out. The capability of the Reynolds Stress model of Speziale (SSG) and the k-ω Shear Stress Transport model (SST) for predicting the supercritical water heat transfer behaviour was evaluated, as well as the effect of mesh structures on the simulation results. The axial temperature distributions of the fuel, cladding, coolant and moderator in the fuel assembly of the HPLWR were obtained. Numerical results of the fuel temperature profiles were compared with those obtained by Waata and a good agreement was achieved. The cladding surface temperature profiles calculated with SSG and SST turbulence models are below the prescribed limits; however, hot spots in one sub-channel were found. The difference in the average thermal-hydraulic properties of the supercritical water calculated with SSG and SST was negligible. However, the fuel and cladding surface temperatures are higher when using the SST model.
Keywords: Ssuper-critical water; HPLWR; CFD; heat transfer deterioration.
Electromagnetic flow meter with non-insulation pipe wall for liquid sodium in nuclear reactors
by Xuejing Li
Abstract: An electromagnetic flow meter (EMFM) with non-insulation pipe wall that may be used in the Fast Reactor Test Facility (FARET) has been designed and partially tested. The internal pipe wall of EMFMs must be non-conductive to prevent generated electromotive force from short-circuiting. Usually, the inside of a metallic pipe is lined with insulating material. The lining limits the applicable temperature range of the measured fluid and also its reliability. A new structure is proposed in this paper, in which the insulating liner is eliminated and the metallic pipe instead of non-insulation material. A servo system is applied. Therefore, the output signal is exactly the same as that of conventional EMFMs. In this paper an analytical method based on conducting wall boundary conditions and experimental results is described.
Keywords: fast reactor test facility; electromagnetic flow meter; boundary conditions.
Understanding the kinetic behaviour of the TRIGA reactor core
by Rashida Yasmeen, Mohammad Sayem Mahmood
Abstract: The kinetic parameters govern the transient behaviour of a nuclear reactor. Estimation of these parameters has great importance for the safe design and operation of a nuclear reactor. In order to understand the kinetic behaviour of the TRIGA core, the influence of graphite dummy elements, absorber materials and beam ports on kinetic parameters has been studied. To do so, the effective delayed neutron fraction (βeff), prompt removal lifetime (ℓ) and mean neutron generation time (Λ) have been calculated for an infinite system of LEU fuel cells. The investigation has been extended to four different cases of the TRIGA reactor core. Monte Carlo simulation has been carried out to compute the kinetic parameters by Monte Carlo code MCNP5. The βeff value remains unchanged but the ℓ and Λ values are found to be sensitive to the local perturbations of the core components.
Keywords: kinetic parameters; effective delayed neutron fraction; prompt removal lifetime; mean neutron generation time; TRIGA; LEU; MCNP.
Influence of Prandtl number on heat transfer of a flat vertical plate
by Abdul Razak Kaladgi, A.D. Mohammed Samee, M.K. Ramis
Abstract: Liquid metals, such as sodium (Na), lead (Pb), and leadbismuth (PbBi) eutectic (e), are considered as potential coolants for the fast spectrum nuclear reactors of the next generation. So the main objective of this paper is to study the heat transfer and fluid flow characteristics of liquid metal coolants flowing over a nuclear fuel element having uniform volumetric energy generation. Stream function vorticity formulation method was used to solve the full Navier Stokes equations governing the flow. The energy equation was solved using the central finite difference method. For the two-dimensional steady state heat conduction and stream-function equation, the discretisation was done in the form suitable to solve using line-by-line Gauss-Seidel solution technique, whereas the discretisation of vorticity transport and energy equations was done using the Alternating Direction Implicit (ADI) scheme. After discretisation the systems of algebraic equations were solved using the Thomas algorithm. The complete work was done by writing a well-validated indigenous computer code written using C-language. The parameters considered for the study were ─ aspect ratio of fuel element, Ar, conduction-convection parameter Ncc, total energy generation parameter Qt, and flow Reynolds number ReH. The results obtained can be used to minimise the maximum temperature in the fuel element (hot spots) and prevent its melting.
Keywords: conjugate heat transfer; Thomas algorithm; ADI scheme; forced convection.
Coupled channel calculations using semiclassical and quantum mechanical approaches for light and medium mass systems
by Fouad A. Majeed, Khalid H. H. AlAteah, Malik S. Mehemed
Abstract: A semiclassical approach and a full quantum mechanical approach have been used to study the effect of channel coupling on the calculations of the total fusion reaction cross-section 𝜎𝑓𝑢𝑠 , the fusion barrier distribution 𝐷𝑓𝑢𝑠 and the reaction probability (prob.) for the light systems (4He+233U, 13C+48Ti) and the medium system (46Ti+46Ti). The semiclassical approach used in the present work based on the method of the Alder and Winther for Coulomb excitation. The results obtained from our semiclassical and full quantum mechanical calculations are compared with the available experimental data. The semiclassical calculations agree reasonably with the full quantum mechanical treatment, and they were able to reproduce the experimental data in detail for the total fusion reaction cross-section 𝜎𝑓𝑢𝑠 , the fusion barrier distribution 𝐷𝑓𝑢𝑠 and the probability of the reaction.
Keywords: semiclassical treatment; quantum treatment; breakup reaction; light systems; medium systems.