A diszkrét tomográfia új irányzatai és alkalmazása a neutron radiográfiában = New directions in discrete tomography and its application in neutron radiography

A projekt során alapvetően a diszkrét tomográfia alábbi területein végeztük eredményes kutatásokat: rekonstrukcó legyezőnyaláb-vetületekből; geometriai tulajdonságokon alapuló rekonsrukciós és egyértelműségi eredmények kiterjeszthetőségének vizsgálata; újfajta geometriai jellemzők bevezetése; egzisztenica, unicitás és rekonstrukció vizsgálata abszorpciós vetületek esetén; 2D és 3D rekonstrukciós algoritmusok fejlesztése neutron tomográfiás alkalmazásokhoz; bináris rekonstrukciós algoritmusok tesztelése, benchmark halmazok és kiértékelések; a rekonstruálandó kép geometriai és egyéb strukturális információinak kinyerése közvetlenül a vetületekből. A kidolgozott eljárásaink egy részét az általunk fejlesztett DIRECT elnevezésű diszkrét tomográfiai keretrendszerben implementáltuk, így lehetőség nyílt az ismertetett eljárások tesztelésére és a különböző megközelítések hatékonyságának összevetésére is. Kutatási eredményeinket több, mint 40 nemzetközi tudományos közleményben jelentettük meg, a projekt futamideje alatt két résztvevő kutató is doktori fokozatot szerzett a kutatási témából. A projekt során több olyan kutatási irányvonalat fedtünk fel, ahol elképzeléseink szerint további jelentős elméleti eredményeket lehet elérni, és ezzel egyidőben a gyakorlat számára is új jellegű és hatékonyabb diszkrét képalkotó eljárások tervezhetők és kivitelezhetők. | In the project entitled ""New Directions in Discrete Tomography and Its Applications in Neutron Radiography"" we did successful research mainly on the following topics on Discrete Tomography (DT): reconstruction from fan-beam projections; extension of uniqueness and reconstruction results of DT based on geometrical priors, introduction of new geometrical properties to facilitate the reconstruction; uniqueness and reconstruction in case of absorbed projections; 2D and 3D reconstruction algorithms for applications in neutron tomography; testing binary reconstruction algorithms, developing benchmark sets and evaluations; exploiting structural features of images from their projections. As a part of the project we implemented some of our reconstruction methods in the DIRECT framework (also developed at our department), thus making it possible to test and compare our algorithms. We published more than 40 articles in international conference proceedings and journals. Two of our project members obtained PhD degree during the period of the project (mostly based on their contributions to the work). We also discovered several research areas where further work can yield important theoretical results as well as more effective discrete reconstruction methods for the applications

CODEX-B4C Experiment: Cored Degradation Test With Boron Carbide Control Rod KFKI-2003-01/G (2003)

The CODEX-B4C bundle test has been successfully performed on 25th May 2001 in the framework of the COLOSS project of the EU 5th FWP. The high temperature degradation of a VVER-1000 type bundle with B4C control rod was investigated with electrically heated fuel rods. The experiment was carried out according to a scenario selected in favour of methane formation. Degradation of control rod and fuel bundle took place at temperatures ~2000 oC, cooling down of the bundle was performed in steam atmosphere. The gas composition measurement indicated no methane production during the experiment. High release of aerosols was detected in the high temperature oxidation phase. The on-line measured data are collected into a database and are available for code validation and development

CODEX-CT-1 experiment: Quenching of fuel bundle after long term oxidation in hydrogen rich steam KFKI-2008-01/G

The cleaning tank incident at the unit 2 of Paks NPP in 2003 resulted in severe fuel damage of 30 assemblies. The fuel rods heated up due to insufficient cooling and the zirconium components suffered heavy oxidation. Opening of the tank and quenching of the assemblies by cold water led to fragmentation of brittle zirconium components. Due to the poor instrumentation there were many open questions concerning the course of the incident and the behaviour of fuel assemblies. In order to improve the understanding of the phenomena that took place during the Paks-2 incident integral tests have been carried out in the CODEX (Core Degradation Experiment) facility. The tests simulated the whole scenario of the incident using electrically heated fuel rods. The final state of the fuel rods showed many similarities with the conditions observed after the incident at the NPP and for this reason it is very probable that the thermal conditions and chemical reactions were also similar in the tests and in the incident. The post-test examination of CODEX-CT-1 bundle indicated that the high degree of embrittlement was a common result of oxidation and hydrogen uptake by the Zr components

CODEX-CT-2 experiment: Long term treatment in high temperature hydrogen and water quenching of a fuel bundle KFKI-2008-02/G

The simulation of the Paks-2 incident was carried out in the frame of an experimental programme in the CODEX facility with electrically heated fuel rod bundles. The main boundary conditions for the CODEX-CT-2 were similar to the previous CODEX-CT-1 test. The most significant difference between the two tests was the operation of the air let down valve that was open in the first test and closed in the second one. In the second test the hydrogen produced in the Zr-steam reaction could not escape from the test section and it prevented the access of steam to the Zr surfaces and caused much less oxidation than was observed in the first tests. The final quench by water led to temperature excursion in the bundle and in the shroud. The final state of the bundle was very brittle, the fuel rods and the shroud were cracked and fragmented

Converting P-GRADE grid portal into e-science gateways

Nowadays there is an increasing need to facilitate the knowledge and research tool sharing and realize effective high-level collaboration among members of the same Virtual Organization. E-Science Gateways are the primary solutions dedicated to support such needs. With E-Science Gateways researchers can use grid infrastructure to run shared, well-tested applications customized to their own research field. In this paper the development lifecycle of an e-Science Gateway is described, role definitions of a generic gridification process is provided and the general steps of the application porting process are also identified. In the second part of the paper a developed external module of P-Grade Grid Portal called Application Specific Module is introduced, which extends the portal’s functionality set. This Application Specific Module allows developers to convert a generic P-GRADE grid portal into a domain specific e-Science Gateway. At the end of the paper two case studies are detailed, to show the development and usage possibilities of the Application Specific Module