Code assessment and modelling for Design Basis Accident Analysis of the European sodium fast reactor design. Part I: System description, modelling and benchmarking

The new reactor concepts proposed in the Generation IV International Forum (GIF) are conceived to improve the use of natural resources, reduce the amount of high-level radioactive waste and excel in their reliability and safe operation. Among these novel designs sodium fast reactors (SFRs) stand out due to their technological feasibility as demonstrated in several countries during the last decades. As part of the contribution of EURATOM to GIF the CP-ESFR is a collaborative project with the objective, among others, to perform extensive analysis on safety issues involving renewed SFR demonstrator designs. The verification of computational tools able to simulate the plant behaviour under postulated accidental conditions by code-to-code comparison was identified as a key point to ensure reactor safety. In this line, several organizations employed coupled neutronic and thermal-hydraulic system codes able to simulate complex and specific phenomena involving multi-physics studies adapted to this particular fast reactor technology. In the “Introduction” of this paper the framework of this study is discussed, the second section describes the envisaged plant design and the commonly agreed upon modelling guidelines. The third section presents a comparative analysis of the calculations performed by each organisation applying their models and codes to a common agreed transient with the objective to harmonize the models as well as validating the implementation of all relevant physical phenomena in the different system codes

Code assessment and modelling for Design Basis Accident analysis of the European Sodium Fast Reactor design. Part II: Optimised core and representative transients analysis

The new reactor concepts proposed in the Generation IV International Forum require the development and validation of computational tools able to assess their safety performance. In the first part of this paper the models of the ESFR design developed by several organisations in the framework of the CP-ESFR project were presented and their reliability validated via a benchmarking exercise. This second part of the paper includes the application of those tools for the analysis of design basis accident (DBC) scenarios of the reference design. Further, this paper also introduces the main features of the core optimisation process carried out within the project with the objective to enhance the core safety performance through the reduction of the positive coolant density reactivity effect. The influence of this optimised core design on the reactor safety performance during the previously analysed transients is also discussed. The conclusion provides an overview of the work performed by the partners involved in the project towards the development and enhancement of computational tools specifically tailored to the evaluation of the safety performance of the Generation IV innovative nuclear reactor designs

Zur Verhinderung organischer Inkrustatierungen beim Waschen mit phosphatfreien und -armen Waschmitteln Schlussbericht

SIGLEAvailable from TIB Hannover: F95B883 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekArbeitsgemeinschaft Industrieller Forschungsvereinigungen e.V., Koeln (Germany)DEGerman

Conceptual design of a He-cooled divertor with integrated flow and heat transfer Promoters (PPCS subtask TW3-TRP-001-D2). Pt. 2 Detailed version

This report represents a summary of our knowledge after little more than one year of development of a helium-cooled divertor. The design goal is to reach at least 10 MW/m"2 at a reasonable pumping power for a fusion power plant operating under DEMO conditions. In the first part, design requirements for the divertor are given and the current design using low-activation materials is described. In the second part, materials choice and promising tungsten alloy materials are pointed out. In view of the operation temperature window defined, materials choice for the divertor components is limited, i.e. tungsten for the thermal shield in the form of small tiles, W-1%La_2O_3 for the thimble, and high-temperature ODS for the back bone structure. To broaden the operating temperature window of the divertor for obtaining a larger safety margin in the design, further development of tungsten alloys as thimble material is required. Promising methods (EDM, ECM and PIM) are identified for the fabrication of pin and slot arrays from tungsten, which need to be further developed. In the third part, computational fluid dynamics (CFD) analyses and thermomechanical finite element (FE) simulation calculations are covered. Comparisons of the pressure loss calculated by the CFD programs with first results of the pressure loss measurement performed at EFREMOV are made, the results are discussed. FE simulations revealed opportunities for the improvement of the design. The last part deals with the planning of experimental devices to confirm the theoretical findings. To validate the CFD programs, helium experiments are planned to be performed in the helium blanket test loop HEBLO at FZK/IMF III in the middle of 2004 using a single finger test mock-up of 10:1 in scale. For the high-heat-flux tests, a large helium loop is planned to be constructed at the EFREMOV Institute in St. Petersburg, Russia. Planning and specification of the experiment programmes are under way. The overall results as presented by this study confirm that the investigated helium-cooled divertor concept HEMP/HEMS has a sufficient potential for resisting the specified heat load of 10 MW/m"2 at a reasonable pumping power. The concept is feasible. (orig.)Available from TIB Hannover: ZA 5141(6975) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Conceptual design of a He-cooled divertor with integrated flow and heat transfer promoters (PPCS subtask TW3-TRP-001-D2). Pt. 1 Summary

Within the framework of the EU power plant conceptual study (PPCS), helium-cooled modular divertor concepts with a flow promoter (HEMP as a pin array and HEMS as slot array version) have been investigated at the Forschungszentrum Karlsruhe since 2002. The design goal is to achieve a high heat flux performance of 15 MW/m"2. In this summary of the detailed report, research areas related to the development of a helium-cooled divertor shall be addressed. Latest changes in thermohydraulic layout as well as current results of simulation calculations shall be presented exemplarily for the slot concept HEMS which has the crucial advantage of being easier to manufacture. The divertor construction resulting from the requirements as well as the design-related issues shall be discussed. Possible manufacturing processes for divertor components of tungsten are assessed. Chapters 7 and 8 have been completely revised comprising the latest results of the thermohydraulic layout and thermomechanical analyses. Calculation results have to be verified by experiments. For this purpose, a helium loop will be built at the Efremov Institute, St. Petersburg, Russia, in 2004. An outlook on an alternative multi-jet design (HEMJ) will be given at the end of this report. (orig.)Available from TIB Hannover: ZA 5141(6974) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman