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Abstract: In a typical pressurized water reactor, neutron detectors located outside the reactor core monitor reactor power. In addition, they are also used to measure the reactivity of the control rods. A novel approach to calculate the ex-core neutron detector response in a typical pressurized water reactor using the Monte Carlo technique is presented. A detailed ex-core model of the Krško nuclear power plant was developed using the Monte Carlo neutron transport code MCNP. Due to the location of the ex-core neutron detectors, the hybrid code ADVANTG is used to generate variance reduction parameters to accelerte the convergence of the results outside the reactor core. To use ADVANTG, the fixed neutron source had to be reconstructed from the criticality core calculation. This paper presents the sensitivity analysis of the response of the ex-core detectors to the neutron data libraries used, the description of the fixed neutron source and the ADVANTG parameters. It was found that a pin-wise description of the neutron source for at least two rows of fuel assemblies at the core periphery is necessary for accurate results. Our results show the importance of a correct description of the prompt neutron spectra in the high energy region and the impact this has on the response of the ex-core detectors. The method in which the prompt neutron fission spectra for important fission nuclides are weighted by the calculated reaction rates has been shown to be the best approximation, with deviations from the reference calculation within statistical uncertainty. The effect of nuclear data libraries on the response of the ex-core detector was investigated, and the difference between the ENDF/B-VII.0 and the ENDF/B-VIII.0 nuclear data libraries was ∼11%. When the deficient evaluation of the 56Fe isotope included in the ENDF/B-VIII.0 nuclear data library was replaced by the improved evaluation from the IAEA INDEN project, the differences decreased to ∼3.7%. In addition, neutron flux redistributions due to control rod movement were investigated and flux redistribution factors were updated using Monte Carlo particle transport methods. The reaction rate redistribution factors obtained with methods presented in this paper are within 1% agreement with the currently used factors.
Keywords: MCNP, ADVANTG, pressurized water reactor, Monte Carlo neutron transport, control rod, neutron flux redistribution factor, rod insertion, krško nuclear power plant
Published in DKUM: 29.11.2024; Views: 0; Downloads: 1
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Abstract: Diplomsko delo je povezano s temo varovanja in pritrjevanja tovora v medskladiščnem transportu. Na začetku je prikazana tematika dela, cilji diplomskega dela in določena raziskovalna vprašanja, ki se bodo obravnavala v diplomskem delu. Raziskovalna vprašanja se nanašajo na odnos med vozniki tovornih vozil in določenimi situacijami v medskladiščnem tovornem prevozu. V teoretičnem delu je predstavljena zakonodaja na področju varovanja in pritrjevanja tovora na področju Slovenije, pomen varovanja in pritrjevanje tovora, tehnike in metode varovanja in pritrjevanja tovora in pripomočki, ki se uporabljajo za varovanje in pritrjevanje tovora v medskladiščnem transportu. V raziskovalnem delu smo opravili anketni vprašalnik za voznike tovornih vozil mase >3,5 t. S pomočjo pridobljenih odgovorov, smo prišli do rezultatov, s katerim smo preverili naša raziskovalna vprašanja in hipoteze. Na podlagi pridobljenih rezultatov, smo ugotovili, da so privezovalni trakovi najbolj uporabljeno sredstvo za varovanje in pritrjevanje tovora. Raziskava tudi potrjuje, da so starejši vozniki, bolj ozaveščeni o pomenu in načinu varovanja in pritrjevanja tovora in da imajo vozniki z več letnimi izkušnjami, manjše težave pri prilagajanju opreme različnim vrstam tovora. V zadnjem delu diplomskega dela smo še podali možne izboljšave na tem področju, ki se nanašajo na izboljšavo usposabljanja voznikov tovornih vozil in povečanje obsega opreme na tovornem vozilu.
Keywords: medskladiščni transport, pritrjevanje tovora, varovanje tovora, pripomočki za pritrjevanje tovora, tehnike in metode pritrjevanja tovora
Published in DKUM: 27.11.2024; Views: 0; Downloads: 3
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Abstract: The European Union’s commitment to sustainable development, exemplifed by the Green Deal and the United Nations Sustainable Development Goals, highlights the importance of the circular economy, especially for road transport companies. This study examines the current state of circular economy practices in Slovenian road transport through an inquiry of 151 logistic companies. Utilizing principal component analysis, fve key factors infuencing circular economy implementation were identifed: knowledge and competences, company practices, strategies, regional development, and market presence. Additionally, seven barriers were noted: lack of knowledge, fnancial constraints, time limitations, space constraints, limited technology, management issues, and supply chain coordination challenges. Findings suggest that circular practices are often secondary to business proftability, with fnancially stable companies more likely to adopt these practices. Success in circular economy implementation requires investments in innovative technologies, capacity building, and strong management support. Companies in more developed regions tend to adopt circular practices due to better access to knowledge and incentives. These insights provide a foundation for future research, including comparative studies across transport sector in European Union and globally.
Keywords: circular economy, logistics sector, PCA, barriers, road transport
Published in DKUM: 25.11.2024; Views: 0; Downloads: 0
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Abstract: The outbreak of COVID-19 caused many changes in people's life. One of the most significant is the travel behaviour and transport mode choice. This study focus on the changes that the inhabitants of Vienna made in their travel choices because of the virus. The same research about spatial modelling the transport mode choice of commuters in Vienna was completed in 2019 and is a topic addressed in our previous work. Based on our developed methodology, this article indicates that public transport is not a dominant transport mode choice as it was before the virus outbreak.The main result of this paper is geographically defined areas of application of individual alternatives shown on the final map of modal shift in Vienna, which could provide theoretical support for policy-makers and transportation planners. For the city of Vienna, we found that the area of the city where cars are now used has increased, which certainly has a negative impact on air quality and life in the city. The advantage of the methodology is that it can also be applied to other cities in the world.
Keywords: coronavirus, city traffic, urban mobility, transport mode choice, passenger transport, geographical methods, spatial modelling, city logistics, Vienna
Published in DKUM: 14.10.2024; Views: 0; Downloads: 17
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Abstract: V diplomskem delu je predstavljen že zmodelirani transportni voz za namen odstranjevanja odrezkov, ki mu je bilo potrebno narediti trdnostno analizo, določiti primerni elektro pogon in zagotoviti večjo varnost zaposlenih v podjetju. V diplomskem delu so najprej predstavljeni transportni vozi: opis transportnih naprav, sestavni deli, uporaba transportnih vozov ter prednosti in slabosti upravljanja z njimi. Sledi trdnostna analiza za ugotavljanje napetosti in povesov transportnega voza v programu PTC Creo. Izdelan je preračun pogona, z namenom izbire primernega elektromotorja in reduktorja. Nato je predstavljena zagotovitev varnosti z vsemi predpisi, ki jih je treba upoštevati, in nevarnostmi, ki se nam lahko pripetijo. Sledi nadgradnja transportnega voza s talnimi označbami in nalepljenimi opozorilnimi trakovi ter svetlobni stolp, ki nam pove, ali je voz pregret in z brenčalom daje zvoke opozarjanja, da je voz v obratovanju. Na koncu pa so v zaključku predstavljeni rezultati našega diplomskega dela.
Keywords: preračun, transport, varnost, pogon
Published in DKUM: 20.09.2024; Views: 0; Downloads: 12
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