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Dose enhancement by gold nanoparticles (AuNP) was shown to increase the biological effectiveness of radiation damage in biomolecules and tissue. Most of the current studies focus on external beam therapy on combination with AuNP. Here we present a Monte-Carlo study (Geant4) to characterise radioactive AuNP. Radioactive 198 Au emits beta and gamma rays and is considered for applications with solid tumours. To effectively apply 198 AuNP their energy deposit characteristics have to be determined in terms of intrinsic and extrinsic properties e.g. AuNP diameter, AuNP density, and their clustering behaviour. After each decay process, the energy deposit, inelastic scattering events, kinetic energy spectrum of secondary particles within the AuNP themselves and in a spherical target volume of water up to 1 μm radius were determined. Simulations were performed for AuNP radii ranging from 2.5 nm to 20 nm radius, different cluster sizes and densities. The results show an increase of the energy deposit in the vicinity of the AuNP up to 150 nm. This effect nearly vanishes for distances up to one micron. For the case of AuNP clusters and the same activity, the enhancement of the energy deposit increases with the relative gold mass percentage and therefore can be adjusted by changing AuNP radius or clustering behaviour.
Computer modelling of non-destructive testing methods has come a long
way from the beginnings in the mid 90s to today. Radiographic modelling for
components with higher wall thicknesses, as they are typical for nuclear
applications, must include precise predictions of scattered radiation and its impact
in terms of contrast reduction. Dedicated or general purpose Monte Carlo methods
with the ability to calculate higher order scattering events are the state of the art for
these applications. Aerospace applications, on the other hand, have stronger
requirements on the modelling code's capabilities to import complex CAD
geometries, and can benefit from faster analytical scatter models, limited to first or
second order scattering events. Similar distinctions can be made for the various
approaches proposed to accurately model geometrical and film unsharpness, film
granularity, film responses, film/foil cartridges and photon noise. This article
presents a state-of-the-art review of radiographic modelling from the perspective of
two important application domains with very different requirements, nuclear and
aerospace.
Hydrogen is an attractive energy carrier that requires high effort for safe storage. For ensuring safety, they must undergo a challenging approval process. Relevant standards and regulations for composite cylinders used for the transport of hydrogen and for its onboard storage are currently based on deterministic (e.g. ISO 11119-3) or semi-probabilistic (UN GTR No. 13) criteria. This paper analysis the properties of such methods with respect to the evaluation of load cycle strength. Their characteristics are compared with the probabilistic approach of the BAM. Based on Monte-Carlo simulations, the available design range (mean value and scatter of strength criteria) of current concepts was exemplarily estimated. The aspect of small sample sizes is analysed and discussed with respect to the evaluation procedures.
Existing regulations and standards for the approval of composite cylinders in hydrogen service are currently based on deterministic criteria (ISO 11119-3, UN GTR No. 13). This paper provides a systematic analysis of the load cycle properties resulting from these regulations and standards. Their characteristics are compared with the probabilistic approach of the BAM. Based on Monte-Carlo simulations the available design range of all concepts is compared. In addition, the probability of acceptance for potentially unsafe design types is determined.
Hydrogen is an attractive energy carrier that requires high effort for safe storage. Forensuring safety, they must undergo a challenging approval process. Relevant standardsand regulations for composite cylinders used for the transport of hydrogen and for its on-board storage are currently based on deterministic (e.g. ISO 11119-3) or semi-probabilistic(UN GTR No. 13) criteria. This paper analysis the properties of such methods withrespect to the evaluation of load cycle strength. Their characteristics are compared withthe probabilistic approach of the BAM. Based on Monte-Carlo simulations, the availabledesign range (mean value and scatter of strength criteria) of current concepts was exem-plarily estimated. The aspect of small sample sizes is analysed and discussed with respectto the evaluation procedures.
Der Vortrag stellte kurz die Abteilung vor und wo der Arbeitsbereich Druckgefäße einzuordnen ist. Er weist auf die Verwendung von Wasserstoff und auf unsere Kompetenz in der Beurteilung von Sicherheit, unsere Beratung und Forschung hin.
Darüber hinaus werden die in der BAM auf Wasserstoffspeicher angewendeten Prüfverfahren dargestellt und als ein Schwerpunkt die hydraulische Prüfung erläutert.
Über die Monte-Carlo-Simulation zur Beurteilung von Vorschriften führt er zum probabilistischen Sicherheitsansatz.
This presentation provides general data about BAM, the structure of department 3 and a short impression of the application of pressure vessels for hydrogen in stationary use, supply chain and onboard storage.
It guides to the actions of BAM as competent authority on this area and shows a lot different methods for testing operated at BAM. Based on this additional research has been detected as necessary for a competent tackling of the tasks as competent authority. After having mentioned several important research projects a figure is presented that compares the development of regulations with relevant re-actions of BAM. The outcome was a concept of a risk based definition of accepted failure rates in combination with probability-oriented safety assessment over entire service life.
The second aspect raised at INERIS is the issue of advising the BMVI concerning pressure vessels for hydrogen. Since the pressure is high for saving material consumption and weight there is still high interest in changing regulatory requirements. Therefor we developed an approach for the display of minimum requirements of regulations in diagrams (sample performance charts; SPC) and the probabilistic analysis for these deterministic requirements. This is done by Monte-Carlo simulation and the analysis of acceptance rate and survival rate of basic populations all over the SPC.
This finally provide same knowledge of non-approvable but safe ranges of parameters and even approvable but non-safe constellations. In addition, this analysis allows to optimise deterministic requirements in regulations to the intended level of safety for approved populations of pressure vessels, which is shown on the example of the GTR#13.