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[en] This report deals with the development of a thermal hydraulic code system for Loss-of-Coolant Accidents of the Advanced Thermal Reactor (ATR). The code system consists of the blowdown analysis codes for large Break LOCA (SENHOR) and Small Break LOCA (LOTRAC), the heatup code (HEATUP) and the reflooding code (FLOOD). Basic models within the codes have been developed and verified by separate effects tests for the important thermal hydraulic phenomena which are expected to occur during an accident in an ATR. The codes are composed of basic models, and have been verified by test on integral facilities, changing the position and the size of the break
[en] The Mathematics and Computations Division of the American Nuclear Society sponsors a standards committee which is designated as the ANS-10 Subcommittee. ANS-10 was formed to develop voluntary guidelines and practices that can serve the Division members and associates. The portability and interchange of computer programs has been an important consideration in this committee's efforts. A summary of past and current activities of ANS-10 is presented. In addition a brief description of the ANSI organization and procedures for standards development is included for background information. 6 references. (U.S.)
[en] Utilities are increasingly realizing the importance of having a full in-house capability in the field of in-core fuel management. This requires competent staff as well as accurate, reliable and easy-to-use computer codes. The development of advanced computer codes is thus an important task for the utilities and the supporting industry. (author)
[en] Highlights: • Review of the requirements and recommendations for BEPU methodology. • Summary of the advantages and limitations of the current deterministic bounding method for non-LOCA transient analysis. • Description of a pragmatic, graded approach for application of the BEPU methodology to non-LOCA transient analysis. • Proposal for a demonstration case. - Abstract: Since 1990’s, the use of best estimate plus uncertainty (BEPU) methodology is becoming a common practice for large-break Loss-Of-Coolant Accident (LOCA) analysis. However, the development and application of BEPU methodology requires a higher-level requirement on the verification and validation, and uncertainty quantification (VVUQ) of the used calculational method and computer codes. This may result in a high-cost for BEPU methodology development, and hence prevent the industry to take full benefit from the BEPU applications. This paper proposes a pragmatic, graded approach for application of the BEPU methodology to non-LOCA transient analyses.
[en] This paper presents an overview of modelling features of the first revision of the V2.1 major version of the European severe accident integral code ASTEC which has been set-up by IRSN and delivered to the ASTEC worldwide community end of 2016. After some generalities concerning the software structure and the packaging of ASTEC V2.1 revision 1, the phenomena addressed by the different modules constitutive of ASTEC are detailed. Finally, perspectives as concerns the development of future versions of ASTEC V2.1 at IRSN are outlined. (author)
[en] After Fukushima Accident there is a worldwide strategy to develop Defense in Depth strategy to mitigate the severe accidents. One of these strategies is in-vessel melt retention. It is a severe accident management strategy which, based on externally flooding the reactor pressure vessel, is aimed at arresting the downward progression of an assumed (unmitigated) core melt accident. The main objective of this paper is the simulation of the VVER-1000 reactor lower head during a severe accident. The results illustrate the lower head failure time due to creep rupture, related to the cavity pool water level. The cavity remains intact if it is full of the coolant before the beginning of slumping to the lower plenum. In this case, the relocated core materials are retained within the vessel. In the performed analysis the critical water level inside the cavity for the mitigation of the in-vessel sever accident, is estimated. (authors)
[en] Green behavior is an important part of the study of green development. To promote green development, it is necessary to engage in further innovation on the basis of lessons from international advancements in green behavior. To clarify the spatial and temporal distribution characteristics of international researchers in the study of green behavior, the research focus, and the research frontiers, a visual analysis was performed on 22,114 articles cited in the SSCI and SCI-EXPANDED databases from 2000 to 2017. This analysis was based on bibliometrics and mapping knowledge domain (MKD) analysis with CiteSpace 5.3.R4, a scientific and technological text-mining and visualization software. The results show that international green behavior research has the following main characteristics. First, a positive correlation was found between the number of papers and time. Second, research is highly valued by researchers in the natural sciences, such as ecology. The USA is involved in major research efforts and maintains a high level of cooperation with other countries and regions. International cooperation among institutions needs to be strengthened. The co-cited journals are primarily academic journals in the natural sciences. Third, research hotspots mainly focus on the theory of planned behavior (TPB), consumers, attitudes, performance, and environment, all of which evolve according to the phase path of “germination-growth.” Fourth, the research frontier issues are largely related to management science and environmental science, and the research objects and methods will become increasingly complex and interdisciplinary over time.