Abstracts - VGB PowerTech Journal 7/2018

Editorial: Communication in change

Christopher Weßelmann

Energy technology and its further development is undoubtedly the strategic element and it is decisive for the long-term success of the so-called “energy transition” and this without restriction to technology. Energy technology has delivered impressive results over the past decades, including for all energy technologies. [more...]

Smart data analysis of the results of ultrasonic inspections for probabilistic fracture mechanics

Johannes Vrana, Kai Kadau and Christian Amann

Most demanding components – for example heavy rotor forgings for the energy sector – are inspected with volumetric and surface detection NDE methods – either manually or using automated systems. The data collected during automated inspection gets processed and analyzed. Similarly, the inspector analyzes the information he sees during manual inspections. The results, like size and position of indications, and the inspection conditions, like sensitivity information and sound attenuation, are finally condensed into reports both for manual and automated inspections. Finally, those reports get printed, signed and archived. However, the data reported in most of those reports is a treasure which needs to be exploited by the NDE community. One key application for such a smart data analysis is probabilistic fracture mechanics. We suggest a better utilization of the NDE inspection data by the implementation of a state of the art data-base for easy access and latest statistical analysis technologies. We report on first results of a newly developed smart data analysis approach on the example of its use for probabilistic fracture mechanics for heavy duty rotor forgings, one of the most demanding components from an inspection and design standpoint. Preliminary analysis, including probability of detection, indication distribution, as well as detection sensitivity comparisons are presented.

Furnace tube life extension in biomass-fired boilers

Colin Davis, Iain Hall and Daniel Spalenka

Dependent upon the fuel composition, biomass fired boilers can suffer unacceptably high fireside corrosion of the furnace wall tubes, with this requiring restricted steam conditions and consequentially relatively low thermal efficiencies, and / or, frequent maintenance / replacement of furnace wall tubing. Corrosion resistant coatings can provide protection from the extremes of fireside corrosion wastage with Alloy 625 weld overlays frequently being utilised. Several alternative coating alloys and application processes exist which could potentially offer cost effective protection. With coating application incurring considerable cost and potentially extended downtime periods for application, boiler operators who are conservative by nature, require some certainty regarding the expected benefits. It is generally accepted that Alloy 625 weld overlay consistently provides good protection and is considered a tried and trusted solution for furnace wall corrosion protection. The selection of alternative coatings and cladding materials and processes is hampered by the lack of long term exposure and comparison with an Alloy 625 weld overlay reference.

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The five essential (´key`) elements of severe accident management – To be developed as part of a SAMG industry standard

George Vayssier

The Fukushima-Daiichi accident in 2011 has caused a renewed interest in the tools and guidelines to mitigate severe accidents. Initiatives have been taken also in other countries, such as the Rapid Deployment Force in France. A number of measures are described in the reports following the European Union stress tests. As a whole, many countries have reviewed and strengthened their approaches in the field of severe accident management. Apart from severe accident mitigating measures - by definition measures after initiation of core damage – also considerable measures have been taken in the preventive field. Technically, the various severe accident management approaches vary considerably: they have different measures, different priorities for the various actions, different staff responsibilities and different sorts of communication to the off-site authorities. It appears that there is no common basis from which the approaches have been developed. In this paper, the five elements are treated which the author considers essential for proper tools to terminate severe accidents and mitigate their consequences. Should these five elements be agreed upon by the SAMG developers, we will have come closer to some form of industry standard for the SAMG, which would be a major step forward.

Re-assessment of RELAP/SCDAPSIM/MOD3.X using historical integral experiments

Chris M. Allison and Judith K. Hohorst

The RELAP/SCDAPSIM code, designed to predict the behavior of reactor systems during normal and accident conditions, is being developed by Innovative Systems Software (ISS) as part of the international SCDAP Development and Training Program (STDP). The ISS developed RELAP/SCDAPSIM uses the publicly available SCDAP/RELAP5 models and correlations developed by the US Nuclear Regulatory Commission in combination with proprietary features developed by ISS and STDP members including (a) advanced programming and numerical methods, (b) advanced user options such as integrated graphical user envi-ronments, coupled 3D reactor kinetics options, and uncertainty analysis methods, and (c) advanced models and correlations. This paper will summarize and describe the new models that were incorporated into the experimental versions of RELAP/SCDAPSIM along with the extensive assessment and verification activities that are currently underway at ISS and various universities and institutes around the world along with examples of thee assessment results. These assessment activities include the verification and validation of the new models by comparing the RELAP/SCDPSIM/MOD3/x calculated results to the meas-ured experimental data as well as to the predicted results from earlier versions of SCDAP and SCDAP/RELAP5 (USNRC codes released in the 1980s and 1990s).

Supercritical water natural circulation flow stability experiment research

Dongliang Ma, Tao Zhou, Bing Li and Yanping Huang

The Thermal hydraulic characteristics of supercritical water natural circulation plays an important role in the safety of the Generation-IV supercritical water-cooled reactors. Hence it is crucial to conduct the natural circulation heat transfer experiment of supercritical water. The heat transfer characteristics have been studied under different system pressures in the natural circulation systems. Results show that the fluctuations in the subcritical flow rate (for natural circulation) is relatively small, as compared to the supercritical flow rate. By increasing the heating power, it is observed that the amplitude (and time period) of the fluctuation tends to become larger for the natural circulation of supercritical water. This tends to show the presence of flow instability in the supercritical water. It is possible to observe the flow instability phenomenon when the system pressure is suddenly reduced from the supercritical pres-sure state to the subcritical state. At the test outlet section, the temperature is prone to increase suddenly, whereas the blocking effect may be

Economical storage systems at the heart of the energy turnaround


The future of solar power depends on efficient storage systems, mainly batteries. However, the business potential of storage technologies is far from ex-hausted. The batteries of the start-up volterion increase an object‘s own power consumption by up to 80 percent – whether in a detached house or in larger buildings. The project qualified by KlimaExpo.NRW thus contributes to the expansion of renewable energies, because with the compact storage facilities the electricity generated can also be used economically at night and during periods of low sunshine.

Technology Centre for Future Energies Licht­enau: Think tank for renewable energies

M.A. Günter Voß

The city of Lichtenau set out early to help shape the energy transition - the Technology Centre Lichtenau (TZL) was created, which serves as a competence centre and think tank for new, forward- looking energy solutions and offers young entrepreneurs and start-ups in the field of renewable energies cost-effective rental space. The centre itself sets a good example and obtains electricity and heat exclusively from renewable energies such as geothermal energy and wind power. For its commitment, the institution was included in the KlimaExpo.NRW as a pacemaker for climate protection.

Is volatile power supply to be tamed by storage?

Albrecht Pfaud

The “energy transition“ causes to the operators of the electricity supply networks not only a short-time volatile demand of electricity, but also due to wind and solar production on the supply side. In order to ensure network stability great efforts have to be undertaken to regulate production and load on a short time scale. But, the crucial question is to ensure a reliable supply in face of shortage and overproduction of electricity by wind and sun for several months, even from year to year. This essay will show some analogy of the design of water retention schemes in water resources management and storage of electricity. The longer the time series used for the designs are, the bigger will be the range, i.e, the capacity of the storage scheme in order to balance supply and load. Given that the capacity is always limited in reality, we examine for a storage based on a “mean year” by testing with the time series 2011 to 2016: how often a failure of the supply will occur (probability), what a quantity is missing (vulnerability) and after what time the system is working normally (resiliency). The assessment of the criteria of risk analysis is highly disappointing. The probability of shortage is too high, the missing energy is hardly to replace, and the failure of energy supply lasts too long.

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