Considerations on a Validation Matrix for System Analysis Codes of Pebble Bed Modular HTRs

Author(s):  
Feng Gou ◽  
Fubing Chen ◽  
Yujie Dong

The modular High Temperature Reactor (HTR) experienced substantial development over the past two decades in China. At present, the 10 MWth experimental reactor HTR-10 is under operation and the 200 MWe demonstration power plant HTR-PM is in its commissioning phase. Both of the HTR-10 and the HTR-PM are pebble bed HTRs designed by the institute of nuclear and new energy technology (INET) of Tsinghua University. In the design and analysis of modular HTRs, system analysis codes play an important role in predicting the reactor behaviour under both normal operation and accident conditions. According to China’s nuclear safety regulations, codes and models employed in the HTR system analysis must be verified and validated in conformance with a specified procedure. Thus, a flowchart is recommended in this paper for the validation of system analysis codes. As the first step of the flowchart, a phenomena identification and ranking table (PIRT) process has been performed on the subject of the HTR-PM thermal hydraulics and accident analysis. In this paper, the PIRT process is introduced and the PIRT results are presented. With the purpose of developing a validation matrix, test data have been collected mainly from the operation history and various tests of the HTR-10. On such basis, some considerations on developing a validation matrix are discussed to benefit the code validation work.

Author(s):  
Min-Hwan Kim ◽  
Hong-Sik Lim ◽  
Won Jae Lee

Assessment of the local hot core temperature during normal operation in a pebble-bed type very high temperature reactor has been carried out by using the computational fluid dynamic (CFD) method for which the boundary conditions were obtained from the results of a macroscopic analysis of the core using a system thermal analysis code, GAMMA. Three pebble arrangements are selected, which are simple cubic (SC), body-centered cubic, and face-centered cubic. The results showed that the SC arrangement having the lowest porosity gives the highest fuel temperature of 1237°C but still below the normal operational fuel limit of 1250°C. Comparison of the CFD results with an empirical correlation was made for the pressure drop and Nusselt number. Both results showed a similar tendency that the pressure drop and the Nusselt number increases as the porosity decreases but there were large differences in their absolute values. The benchmark calculation for the pressure drop of the packed particles in a square channel indicated that the correlation for the full core used in the system code is not appropriate for the prediction of a local thermal-fluid behavior in an ordered pebble arrangement.


Author(s):  
Min-Hwan Kim ◽  
Hong-Sik Lim ◽  
Won Jae Lee

Assessment of the local hot core temperature during normal operation in a pebble-bed type of Very High Temperature Reactor (VHTR) has been carried out by using the Computational Fluid Dynamic (CFD) method for which the boundary conditions were obtained from the results of a macroscopic analysis of the core using a system thermal analysis code, GAMMA. Three pebble arrangements are selected, which are Simple Cubic (SC), Body-Centered Cubic (BCC), and Face-Centered Cubic (FCC). Results showed that the SC arrangement having the lowest porosity gives the highest fuel temperature of 1237°C but still below the normal operational fuel limit of 1250°C. Comparison of the CFD results with an empirical correlation was made for the pressure drop and the Nusselt number but there were large differences between them. The benchmark calculation of a pressure drop for packed particles in a square channel indicated that the correlation for the full core used in the system code is not appropriate for the prediction of a local thermal fluid behavior.


2020 ◽  
Vol 17 (1) ◽  
pp. 58-67
Author(s):  
N. A. Kabanova ◽  
I. K. Alekseeva

The article is devoted to the assessment of potential investment risks of the pharmaceutical company “R-Pharm” JSC with the aim of identifying the highest priority risks and developing methods for minimizing them. The relevance of the study is determined by the fact that the pharmaceutical business is characterized by a high degree of social orientation and annually invests $ 140 billion in the development of production and research, which determines the need for a risk-based approach to ensure the return on investment. The subject of this article is the investment risks of pharmaceutical companies, and the subject of research is the domestic pharmaceutical company “R-Pharm”. In order to assess the potential investment risks of “R-Pharm” JSC, the authors used elements of simulation modeling and system analysis. The proposed methods to minimize key investment risks are aimed at improving the efficiency of investment activities and is recommended as an element of the strategic planning of the company.


1997 ◽  
Vol 36 (4I) ◽  
pp. 321-331
Author(s):  
Sarfraz Khan Qureshi

It is an honour for me as President of the Pakistan Society of Development Economists to welcome you to the 13th Annual General Meeting and Conference of the Society. I consider it a great privilege to do so as this Meeting coincides with the Golden Jubilee celebrations of the state of Pakistan, a state which emerged on the map of the postwar world as a result of the Muslim freedom movement in the Indian Subcontinent. Fifty years to the date, we have been jubilant about it, and both as citizens of Pakistan and professionals in the social sciences we have also been thoughtful about it. We are trying to see what development has meant in Pakistan in the past half century. As there are so many dimensions that the subject has now come to have since its rather simplistic beginnings, we thought the Golden Jubilee of Pakistan to be an appropriate occasion for such stock-taking.


Author(s):  
Daiva Milinkevičiūtė

The Age of Enlightenment is defined as the period when the universal ideas of progress, deism, humanism, naturalism and others were materialized and became a golden age for freemasons. It is wrong to assume that old and conservative Christian ideas were rejected. Conversely, freemasons put them into new general shapes and expressed them with the help of symbols in their daily routine. Symbols of freemasons had close ties with the past and gave them, on the one hand, a visible instrument, such as rituals and ideas to sense the transcendental, and on the other, intense gnostic aspirations. Freemasons put in a great amount of effort to improve themselves and to create their identity with the help of myths and symbols. It traces its origins to the biblical builders of King Solomon’s Temple, the posterity of the Templar Knights, and associations of the medieval craft guilds, which were also symbolical and became their link not only to each other but also to the secular world. In this work we analysed codified masonic symbols used in their rituals. The subject of our research is the universal Masonic idea and its aspects through the symbols in the daily life of the freemasons in Vilnius. Thanks to freemasons’ signets, we could find continuity, reception, and transformation of universal masonic ideas in the Lithuanian freemasonry and national characteristics of lodges. Taking everything into account, our article shows how the universal idea of freemasonry spread among Lithuanian freemasonry, and which forms and meanings it incorporated in its symbols. The objective of this research is to find a universal Masonic idea throughout their visual and oral symbols and see its impact on the daily life of the masons in Vilnius. Keywords: Freemasonry, Bible, lodge, symbols, rituals, freemasons’ signets.


No other talent process has been the subject of such great debate and emotion as performance management (PM). For decades, different strategies have been tried to improve PM processes, yielding an endless cycle of reform to capture the next “flavor-of-the-day” PM trend. The past 5 years, however, have brought novel thinking that is different from past trends. Companies are reducing their formal processes, driving performance-based cultures, and embedding effective PM behavior into daily work rather than relying on annual reviews to drive these. Through case studies provided from leading organizations, this book illustrates the range of PM processes that companies are using today. These show a shift away from adopting someone else’s best practice; instead, companies are designing bespoke PM processes that fit their specific strategy, climate, and needs. Leading PM thought leaders offer their views about the state of PM today, what we have learned and where we need to focus future efforts, including provocative new research that shows what matters most in driving high performance. This book is a call to action for talent management professionals to go beyond traditional best practice and provide thought leadership in designing PM processes and systems that will enhance both individual and organizational performance.


Urban Science ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 70
Author(s):  
Till Koglin ◽  
Lucas Glasare

This paper evaluates the history and cycling accessibility of Nova, a shopping centre established in Lund, Sweden, in 2002. The current situation was also analysed through observation and a literature review. Moreover, the study conducted a closer analysis of the history and role of the municipality based on further literature study and interviews with officials. The conclusion of the analysis indicates poor and unsafe bikeways caused by conflicts of interest between politicians, officials, landowners and the general public. It also depicts a situation in which the municipality’s master plan has been ignored, and, in contrast to the local goals, cycling accessibility at Nova has seen no significant improvement since the shopping centre was first established. The reasons for this, arguably, are a relatively low budget for bikeway improvements in the municipality, as well as a situation in which decision-makers have stopped approaching the subject, as a result of the long and often boisterous conflicts it has created in the past. Lastly, it must be noted that it is easy to regard the whole process of Nova, from its establishment to the current situation, as being symptomatic of the power structures between drivers and cyclists that still affect decision-makers at all levels.


Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 169
Author(s):  
Cristina Lazzeroni ◽  
Sandra Malvezzi ◽  
Andrea Quadri

The rapid changes in science and technology witnessed in recent decades have significantly contributed to the arousal of the awareness by decision-makers and the public as a whole of the need to strengthen the connection between outreach activities of universities and research institutes and the activities of educational institutions, with a central role played by schools. While the relevance of the problem is nowadays unquestioned, no unique and fully satisfactory solution has been identified. In the present paper we would like to contribute to the discussion on the subject by reporting on an ongoing project aimed to teach Particle Physics in primary schools. We will start from the past and currently planned activities in this project in order to establish a broader framework to describe the conditions for the fruitful interplay between researchers and teachers. We will also emphasize some aspects related to the dissemination of outreach materials by research institutions, in order to promote the access and distribution of scientific information in a way suited to the different age of the target students.


2020 ◽  
Author(s):  
Léon E Dijkman

Abstract Germany is one of few jurisdictions with a bifurcated patent system, under which infringement and validity of a patent are established in separate proceedings. Because validity proceedings normally take longer to conclude, it can occur that remedies for infringement are imposed before a decision on the patent’s validity is available. This phenomenon is colloquially known as the ‘injunction gap’ and has been the subject of increasing criticism over the past years. In this article, I examine the injunction gap from the perspective of the right to a fair trial enshrined in Art. 6 of the European Convention on Human Rights. I find that the case law of the European Court of Human Rights interpreting this provision supports criticism of the injunction gap, because imposing infringement remedies with potentially far-reaching consequences before the validity of a patent has been established by a court of law arguably violates defendants’ right to be heard. Such reliance on the patent office’s grant decision is no longer warranted in the light of contemporary invalidation rates. I conclude that the proliferation of the injunction gap should be curbed by an approach to a stay of proceedings which is in line with the test for stays as formulated by Germany’s Federal Supreme Court. Under this test, courts should stay infringement proceedings until the Federal Patent Court or the EPO’s Board of Appeal have ruled on the validity of a patent whenever it is more likely than not that it will be invalidated.


2021 ◽  
Vol 151 ◽  
pp. 107983
Author(s):  
Lianjie Wang ◽  
Wei Sun ◽  
Bangyang Xia ◽  
Yang Zou ◽  
Rui Yan

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