Development of an HTR-10 model in the Serpent reactor physics code

The use of exact coordinates of pebbles and fuel particles of pebble bed reactor modelling becoming possible in Monte Carlo reactor physics calculations is an important development step. This allows exact modelling of pebble bed reactors with realistic pebble beds without the placing of pebbles in regular lattices. In this study the multiplication coefficient of the HTR-10 pebble bed reactor is calculated with the Serpent reactor physics code and, using this multiplication coefficient, the amount of pebbles required for the critical load of the reactor. The multiplication coefficient is calculated using pebble beds produced with the discrete element method and three different material libraries in order to compare the results. The received results are lower than those from measured at the experimental reactor and somewhat lower than those gained with other codes in earlier studies.

Automating The User Interface Implementation Process by Code Generation

3G-radioverkon asetusten hallinnointi suoritetaan säätämällä radioverkkotietokantaan talletettavia parametreja. Hallinnointiohjelmistossa tuhannetradioverkon parametrit näkyvät käyttöliittymäkomponentteina, joita ohjelmiston kehityskaaressa jatkuvasti lisätään, muutetaan ja poistetaan asiakkaan tarpeidenmukaan. Parametrien lisäämisen toteutusprosessi on ohjelmistokehittäjälle työlästä ja mekaanista. Diplomityön tavoitteeksi asetettiin kehittää koodigeneraattori, joka luo kaiken toteutusprosessissa tuotetun koodin automaattisesti niistä määrittelyistä, jotka ovat nykyäänkin saatavilla. Työssä kehitetty generaattori nopeuttaa ohjelmoijan työtä eliminoimalla yhden aikaa vievän ja mekaanisen työvaiheen. Seurauksena saadaan yhtenäisempää ohjelmistokoodia ja säästetään yrityksen ohjelmistotuotannon kuluissa, kun ohjelmoijan taito voidaan keskittää vaativimpiin tehtäviin.

Code Generator for Key Management Protocols - Design and Implementation

Key management has a fundamental role in secure communications. Designing and testing of key management protocols is tricky. These protocols must work flawlessly despite of any abuse. The main objective of this work was to design and implement a tool that helps to specify the protocol and makes it possible to test the protocol while it is still under development. This tool generates compile-ready java code from a key management protocol model. A modelling method for these protocols, which uses Unified Modeling Language (UML) was also developed. The protocol is modelled, exported as an XMI and read by the code generator tool. The code generator generates java code that is immediately executable with a test software after compilation.

Development of a PC Tool for Estimating Pressure Drops in Forced-convection Boiler Tubes

Kaksifaasivirtauksen kuvaamiseen käytettävät mallit, ja menetelmät kaksifaasivirtauksen painehäviön määrittämiseksi kehittyvät yhä monimutkaisimmiksi. Höyrystinputkissa tapahtuvien painehäviöiden arvioinnin vaatiman laskennan suorittamiseksi tietokoneohjelman kehittäminen on välttämätöntä. Tässä työssä on kehitetty itsenäinen PC-ohjelma painehäviöiden arvioimiseksi pakotetulle konvektiovirtaukselle pystysuorissa höyrykattilan höyrystinputkissa. Veden ja vesihöyryn aineominaisuuksien laskentaan käytetään IAPWS-IF97 –yhtälökokoelmaa sekä muita tarvittavia IAPWS:n suosittelemia yhtälöitä. Höyrystinputkessa kulloinkin vallitsevan virtausmuodon määrittämiseen käytetään sovelluskelpoisia virtausmuotojen välisiä rajoja kuvaavia yhtälöitä. Ohjelmassa käytetään painehäviön määritykseen kirjallisuudessa julkaistuja yhtälöitä, virtausmuodosta riippuen, alijäähtyneelle virtaukselle, kupla-, tulppa- ja rengasvirtaukselle sekä tulistetun höyryn virtaukselle. Ohjelman laskemia painehäviöarvioita verrattiin kirjallisuudesta valittuihin mittaustuloksiin. Laskettujen painehäviöiden virhe vaihteli välillä –19.5 ja +23.9 %. Virheiden itseisarvojen keskiarvo oli 12.8 %.

Developing a user-centric event management system

This thesis describes the development of a software requirements specification for a user-centric event management system. The system is set to satisfy three goals: adding value for the event attendees, adding value for the event organizer, and reducing the costs of arranging and running an event. The requirements are identified by researching the prescriptive traits of event business and the current state of the case company and its environment. First the professional and human needs for events are scrutinized. Second, some recent reports about the current trends in the event business are reviewed. Then the event life cycle is presented using the model of new service development, and online promotion of events and especially word-of-mouth marketing receive special attention. Events are also regarded from the perspective of social networks and social media. The case company’s current state and its competitors are reviewed to formulate the needs which the system should fulfil. Then the currently available solutions for social media oriented event management are reviewed. The result is a set of functional and non-functional requirements. The functional requirements are categorized into social media, social networking, event personalization, event management, and system administration features. The specified features and non-functional requirements satisfy the three goals set for the system.

Transforming Maritime Safety Culture. Evaluation of the impacts of the ISM Code on maritime safety culture in Finland

The purpose of the METKU Project (Development of Maritime Safety Culture) is to study how the ISM Code has influenced the safety culture in the maritime industry. This literature review is written as a part of the Work Package 2 which is conducted by the University of Turku, Centre for Maritime Studies. The maritime traffic is rapidly growing in the Baltic Sea which leads to a growing risk of maritime accidents. Particularly in the Gulf of Finland, the high volume of traffic causes a high risk of maritime accidents. The growing risks give us good reasons for implementing the research project concerning maritime safety and the effectiveness of the safety measures, such as the safety management systems. In order to reduce maritime safety risks, the safety management systems should be further developed. The METKU Project has been launched to examine the improvements which can be done to the safety management systems. Human errors are considered as the most important reason for maritime accidents. The international safety management code (the ISM Code) has been established to cut down the occurrence of human errors by creating a safety-oriented organizational culture for the maritime industry. The ISM Code requires that a company should provide safe practices in ship operation and a safe working environment and establish safeguards against all identified risk. The fundamental idea of the ISM Code is that companies should continuously improve safety. The commitment of the top management is essential for implementing a safety-oriented culture in a company. The ISM Code has brought a significant contribution to the progress of maritime safety in recent years. Shipping companies and ships’ crews are more environmentally friendly and more safety-oriented than 12 years ago. This has been showed by several studies which have been analysed for this literature research. Nevertheless, the direct effect and influence of the ISM Code on maritime safety could not be isolated very well. No quantitative measurement (statistics/hard data) could be found in order to present the impacts of the ISM Code on maritime safety. In this study it has been discovered that safety culture has emerged and it is developing in the maritime industry. Even though the roots of the safety culture have been established there are still serious barriers to the breakthrough of the safety management. These barriers could be envisaged as cultural factors preventing the safety process. Even though the ISM Code has been effective over a decade, the old-established behaviour which is based on the old day’s maritime culture still occurs. In the next phase of this research project, these cultural factors shall be analysed in regard to the present safety culture of the maritime industry in Finland.

Modelling of the PWR PACTEL vertical steam generator with the TRACE code

The behavior of the nuclear power plants must be known in all operational situations. Thermal hydraulics computer applications are used to simulate the behavior of the plants. The computer applications must be validated before they can be used reliably. The simulation results are compared against the experimental results. In this thesis a model of the PWR PACTEL steam generator was prepared with the TRAC/RELAP Advanced Computational Engine computer application. The simulation results can be compared against the results of the Advanced Process Simulator analysis software in future. Development of the model of the PWR PACTEL vertical steam generator is introduced in this thesis. Loss of feedwater transient simulation examples were carried out with the model.

A Model-Based Development and Verification Framework for Distributed System-on-Chip Architecture

The capabilities and thus, design complexity of VLSI-based embedded systems have increased tremendously in recent years, riding the wave of Moore’s law. The time-to-market requirements are also shrinking, imposing challenges to the designers, which in turn, seek to adopt new design methods to increase their productivity. As an answer to these new pressures, modern day systems have moved towards on-chip multiprocessing technologies. New architectures have emerged in on-chip multiprocessing in order to utilize the tremendous advances of fabrication technology. Platform-based design is a possible solution in addressing these challenges. The principle behind the approach is to separate the functionality of an application from the organization and communication architecture of hardware platform at several levels of abstraction. The existing design methodologies pertaining to platform-based design approach don’t provide full automation at every level of the design processes, and sometimes, the co-design of platform-based systems lead to sub-optimal systems. In addition, the design productivity gap in multiprocessor systems remain a key challenge due to existing design methodologies. This thesis addresses the aforementioned challenges and discusses the creation of a development framework for a platform-based system design, in the context of the SegBus platform - a distributed communication architecture. This research aims to provide automated procedures for platform design and application mapping. Structural verification support is also featured thus ensuring correct-by-design platforms. The solution is based on a model-based process. Both the platform and the application are modeled using the Unified Modeling Language. This thesis develops a Domain Specific Language to support platform modeling based on a corresponding UML profile. Object Constraint Language constraints are used to support structurally correct platform construction. An emulator is thus introduced to allow as much as possible accurate performance estimation of the solution, at high abstraction levels. VHDL code is automatically generated, in the form of “snippets” to be employed in the arbiter modules of the platform, as required by the application. The resulting framework is applied in building an actual design solution for an MP3 stereo audio decoder application.

Software and Code Finder: making research outputs visible

Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Application and development of numerical methods for the modelling of innovative gas cooled fission reactors

Innovative gas cooled reactors, such as the pebble bed reactor (PBR) and the gas cooled fast reactor (GFR) offer higher efficiency and new application areas for nuclear energy. Numerical methods were applied and developed to analyse the specific features of these reactor types with fully three dimensional calculation models. In the first part of this thesis, discrete element method (DEM) was used for a physically realistic modelling of the packing of fuel pebbles in PBR geometries and methods were developed for utilising the DEM results in subsequent reactor physics and thermal-hydraulics calculations. In the second part, the flow and heat transfer for a single gas cooled fuel rod of a GFR were investigated with computational fluid dynamics (CFD) methods. An in-house DEM implementation was validated and used for packing simulations, in which the effect of several parameters on the resulting average packing density was investigated. The restitution coefficient was found out to have the most significant effect. The results can be utilised in further work to obtain a pebble bed with a specific packing density. The packing structures of selected pebble beds were also analysed in detail and local variations in the packing density were observed, which should be taken into account especially in the reactor core thermal-hydraulic analyses. Two open source DEM codes were used to produce stochastic pebble bed configurations to add realism and improve the accuracy of criticality calculations performed with the Monte Carlo reactor physics code Serpent. Russian ASTRA criticality experiments were calculated. Pebble beds corresponding to the experimental specifications within measurement uncertainties were produced in DEM simulations and successfully exported into the subsequent reactor physics analysis. With the developed approach, two typical issues in Monte Carlo reactor physics calculations of pebble bed geometries were avoided. A novel method was developed and implemented as a MATLAB code to calculate porosities in the cells of a CFD calculation mesh constructed over a pebble bed obtained from DEM simulations. The code was further developed to distribute power and temperature data accurately between discrete based reactor physics and continuum based thermal-hydraulics models to enable coupled reactor core calculations. The developed method was also found useful for analysing sphere packings in general. CFD calculations were performed to investigate the pressure losses and heat transfer in three dimensional air cooled smooth and rib roughened rod geometries, housed inside a hexagonal flow channel representing a sub-channel of a single fuel rod of a GFR. The CFD geometry represented the test section of the L-STAR experimental facility at Karlsruhe Institute of Technology and the calculation results were compared to the corresponding experimental results. Knowledge was gained of the adequacy of various turbulence models and of the modelling requirements and issues related to the specific application. The obtained pressure loss results were in a relatively good agreement with the experimental data. Heat transfer in the smooth rod geometry was somewhat under predicted, which can partly be explained by unaccounted heat losses and uncertainties. In the rib roughened geometry heat transfer was severely under predicted by the used realisable k − epsilon turbulence model. An additional calculation with a v2 − f turbulence model showed significant improvement in the heat transfer results, which is most likely due to the better performance of the model in separated flow problems. Further investigations are suggested before using CFD to make conclusions of the heat transfer performance of rib roughened GFR fuel rod geometries. It is suggested that the viewpoints of numerical modelling are included in the planning of experiments to ease the challenging model construction and simulations and to avoid introducing additional sources of uncertainties. To facilitate the use of advanced calculation approaches, multi-physical aspects in experiments should also be considered and documented in a reasonable detail.

Supplier segmentation and development in project business

The purpose of this study was to expand the applicability of supplier segmentation and development approaches to the project-driven construction industry. These practices are less exploited and not well documented in this operational environment compared to the process-centric manufacturing industry. At first, portfolio models to supply base segmentation and various supplier development efforts were investigated in literature review. A step-wise framework was structured for the empirical research. The empirical study employed multiple research methods in three case studies in a large Finnish construction company. The first study categorized the construction item classes into the purchasing portfolio and positioned suppliers to the power matrix by investigating buyer-supplier relations. Using statistical tests, the study also identified factors that affect suppliers’ performance. The final case study identified improvement areas of the interface between a main contractor and one if its largest suppliers. The final results indicate that only by assessing the supply base in a holistic manner and the power circumstances in it, buyers comprehend how to best establish appropriate supplier development strategies in the project environment.

A human-centric service approach for architecting and reengineering global system

Production of a new system in any range is expanding dramatically and new ideas are there upon introduced, the logic stands behind the matter is the growth of application of the internet and granting web-based systems. Before producing a system and distribute to the customer, various aspects should be studied which multiple the profit of the system. The process of productizing a new system from being unprocessed idea until delivers to the final user has been unambiguous. In this thesis, the systematize service in a way that benefits both the customer and provider, along with an effort to establish trust and diminish customer’s risk and increase service productivity are in detail presented. Characteristics of Servitization and Productization as two faces of one coin have been interpreted. Apart from the abovementioned issues state of art, service-oriented architecture (SOA) and New Service Development (NSD) has been included in this report for solving the problem of gradually decline in value of companies.