Eddy current testing probe optimization using a parallel genetic algorithm

This paper uses the developed parallel version of Michalewicz's Genocop III Genetic Algorithm (GA) searching technique to optimize the coil geometry of an eddy current non-destructive testing probe (ECTP). The electromagnetic field is computed using FEMM 2D finite element code. The aim of this optimization was to determine coil dimensions and positions that improve ECTP sensitivity to physical properties of the tested devices

SYSTEMATIC QUALIFICATION OF THE COUPLED NEUTRON TRANSPORT AND THERMAL-HYDRAULICS CODE DORT-TD/THERMIX

ABSTRACT In order to present credible results in nuclear design and safety analysis, computer codes must adhere to stringent qualification procedures imposed by nuclear licensing authorities. Such procedures form the basis for a quality assured verification and validation process. This is particularly true for advanced nuclear systems of Generation IV type, where little licensing experience exists as well as little or no plant data is available. Qualification of nuclear design and analysis codes can be achieved in various ways, namely: comparison of results from a code with results from another code i.e. code to code benchmarking; comparison of results from a given code with experimental results, i.e. code to experiment benchmarking; comparison of results from a given code with operational plant data; and finally, comparison of the results of a given code with known analytical solutions. In this paper, a systematic qualification of the coupled neutron transport and thermal hydraulics code DORT-TD/THERMIX is presented. As part of developing this coupled code to the level where it can be used as an independent tool by both designers of pebble-bed High-Temperature Gas-cooled Reactors (HTGRs) and regulators, an effort has been made to verify the coupling scheme as well as the validity of application for this code package. At these initial stages a code to code comparison has been adopted as the qualification method of choice. This is done for both steady-state and transient benchmark problems, ranging from simplified to detailed models. As shown in the results section, all benchmarks have been successfully recalculated and generally show good to very good agreement with the "reference" solutions

Experience on the treatment of anorectal abscesses with primary or ligation fistulotomy

INTRODUCTION: Anorectal abscess (ARA) is frequently treated inappropriately with a simple incision and drainage. In 30-50% of the patients this leads to recurrent ARA, chronic rectal fistula and several hos­pital admissions.PATIENTS AND METHODS: For a ten years period, from 2007 till 2016, 547 patients with ARA were operated. Males were 419 and females 128, with a ratio of 3.3:1. Depending on localization, we divide four types of ARA: perianal - 281 patients (51.4%), ischiorectal - 176 patients (32.2%), intersphincteric - 56 pa­tients (10.2%), supralevator - 34 patients (6.2%).RESULTS: Radical operative treatment of ARA depends of type and location of abscess, its relationship to the sphincter and the extent of the inflammatory process. In 204 patients (37.3%) was performed incision, revision and drainage. In perianal, lower types of intersphincteric ARA incision, revision, excision of the fistula and the crypt is performed. This kind of operation we carried out on 181 patients (33.1%). In all is­chiorectal, high intersphincteric and supralevator ARA we made wide incision, digital revision, necrecto­my, drainage and seton ligation for gradual and continuous section of the sphincter, performed on 162 pa­tients (29.6%).CONCLUSIONS: Surgical tactics based on individual and differentiated approach of ARA treatment in specialized coloproctologic clinics assures effective and radical management, avoiding secondary abscess or chronic fistulization. Although still on debate, the primary or ligation fistulotomy should become a meth­od of choice for the radical treatment of ARA, eliminating the possibility of recurrent inflammation or fis­tula-in-ano. Scr Sci Med 2017; 49(3): 45-4

Preservation of kinetics parameters generated by Monte Carlo calculations in two-step deterministic calculations

The generation of accurate kinetic parameters such as mean generation time Λ and effective delayed neutron fraction βeff via Monte Carlo codes is established. Employing these in downstream deterministic codes warrants another step to ensure no additional error is introduced by the low-order transport operator when computing forward and adjoint fluxes for bilinear weighting of these parameters. Another complexity stems from applying superhomogenization (SPH) equivalence in non-fundamental mode approximations, where reference and low-order calculations rely on a 3D full core model. In these cases, SPH factors can optionally be computed for only part of the geometry while preserving reaction rates and K-effective, but the impact of such approximations on kinetics parameters has not been thoroughly studied. This paper aims at studying the preservation of bilinearly-weighted quantities in the Serpent–Griffin calculation procedure. Diffusion and transport evaluations of IPEN/MB-01, Godiva, and Flattop were carried out with the Griffin reactor physics code, testing available modeling options using Serpent-generated multigroup cross sections and equivalence data. Verifying Griffin against Serpent indicates sensitivities to multigroup energy grid selection and regional application of SPH equivalence, introducing significant errors; these were demonstrated to be reduced through the use of a transport method together with a finer energy grid

Deformation of the Planetary Orbits Caused by the Time Dependent Gravitational Potential in the Universe

In the paper are studied the deformations of the planetary orbits caused by the time dependent gravitational potential in the universe. It is shown that the orbits are not axially symmetric and the time dependent potential does not cause perihelion precession. It is found a simple formula for the change of the orbit period caused by the time dependent gravitational potential and it is tested for two binary pulsars.Comment: 7 page

Refrigerated warehouses as intelligent hubs to integrate renewable energy in industrial food refrigeration and to enhance power grid sustainability

Background Independence from fossil fuels, energy diversification, decarbonisation and energy efficiency are key prerequisites to make a national, regional or continental economy competitive in the global marketplace. As Europe is about to generate 20% of its energy demand from Renewable Energy Sources (RES) by 2020, adequate RES integration and renewable energy storage throughout the entire food cold chain must properly be addressed. Scope and approach Refrigerated warehouses for chilled and frozen foods are large energy consumers and account for a significant portion of the global energy demand. Nevertheless, the opportunity for RES integration in the energy supply of large food storage facilities is often neglected. In situ power generation using RES permits capture of a large portion of virtually free energy, thereby reducing dramatically the running costs and carbon footprint, while enhancing the economic competitiveness. In that context, there exist promising engineering solutions to exploit various renewables in the food preservation sector, in combination with the emerging sustainability-enhancing technology of Cryogenic Energy Storage (CES). Key findings and conclusions Substantial research endeavours are driven by the noble objective to turn the Europe's Energy Union into the world's number one in renewable energies. Integrating RES, in synchrony with CES development and proper control, is capable of both strengthening the food refrigeration sector and improving dramatically the power grid balance and energy system sustainability. Hence, this article aims to familiarise stakeholders of the European and global food preservation industry with state-of-the-art knowledge, know-how, opportunities and professional achievements in the concerned field

Heuristic Rules Embedded Genetic Algorithm to Solve In-Core Fuel Management Optimization Problem

Because of the large number of possible combinations for the fuel assembly loading in the core, the design of the loading pattern (LP) is a complex optimization problem. It requires finding an optimal fuel arrangement in order to achieve maximum cycle length while satisfying the safety constraints. The objective of this study is to develop a loading pattern optimization code. Generally in-core fuel management codes are written for specific cores and limited fuel inventory. One of the goals of this study is to develop a loading pattern optimization code, which is applicable for all types of Pressurized Water Reactor (PWR) core structures with unlimited number of fuel assembly types in the inventory. To reach this goal an innovative genetic algorithm is developed with modifying the classical representation of the genotype. To obtain the best result in a shorter time not only the representation is changed but also the algorithm is changed to use in-core fuel management heuristics rules. The improved GA code was tested demonstrating the advantages of the introduced enhancements. The core physics code used in this research is Moby-Dick, which was developed to analyze the VVER reactors by SKODA Inc

High-Fidelity Coupled Monte-Carlo/Thermal-Hydraulics Calculations

Monte Carlo methods have been used as reference reactor physics calculation tools worldwide. The advance in computer technology allows the calculation of detailed flux distributions in both space and energy. In most of the cases however, those calculations are done under the assumption of homogeneous material density and temperature distributions. The aim of this work is to develop a consistent methodology for providing realistic three-dimensional thermal-hydraulic distributions by coupling the in-house developed sub-channel code SUBCHANFLOW with the standard Monte-Carlo transport code MCNP. In addition to the innovative technique of on-the fly material definition, a flux-based weight-window technique has been introduced to improve both the magnitude and the distribution of the relative errors. Finally, a coupled code system for the simulation of steady-state reactor physics problems has been developed. Besides the problem of effective feedback data interchange between the codes, the treatment of temperature dependence of the continuous energy nuclear data has been investigated