Literature review of lead-lithium thermophysical properties

Abstract In recent years, the scientific community of nuclear fusion raised the issue of thermophysical properties of lead lithium alloys. These alloys are foreseen to be used in several Breeding Blanket concepts in an almost eutectic composition, but only few data on the properties are available in literature and large differences on the same property exist between different authors. Moreover, apparently each organization used different available properties correlations, making practically pointless every comparison of results with the other organizations involved in the design of Breeding Blankets. The aim of this paper is to identify the properties to be used in the design of the Breeding Blankets, performing a literature review of the available data and suggesting a correlation for each of the main properties. These correlations were chosen based on the accurateness of the paper and on the similarities between different authors, where it was possible (e.g., density). The table with the correlations should represent a starting point for a discussion to reach a general consensus on the property database, which should be mandatory in order to allow a comparison of the results from different organizations. Very likely new experiments will be necessary to definitely measure at least the properties with the biggest scattering of the data (e.g., specific heat), encouraging a consensus and reducing the errors in the design activities

An analytical approach for the sequential excavation of axisymmetric lined tunnels in viscoelastic rock

The main factors for the observed time dependency in tunnel construction are due to the sequence of excavation, the number of liners and their times of installation and the rheological properties of the host rock. A generalized derivation procedure for any viscoelastic model is presented accounting for the sequential excavation of a circular tunnel supported by any number of liners of different thicknesses and stiffnesses installed at different times in a viscoelastic surrounding rock under a hydrostatic stress field under plane strain axisymmetric conditions. Sequential excavation was accounted for assuming the radius of the tunnel growing from an initial value to a final one according to a time-dependent function to be prescribed by the designer. The effect of tunnel advancement was also considered. For the generalized Kelvin viscoelastic model, explicit analytical closed form solutions were presented, which can be reduced to the solutions for the Maxwell and Kelvin models

Experiments on the MHD Effect on the Drainage of a LiPb Channel and Supporting Numerical Computations with the Level Set Method

To analyze the impact of the magnetohydrodynamics (MHD) effect on the fast draining of a LiPb channel (lithium-lead eutectic, 15.7 at. % Li) for a liquid metal fusion blanket such as the water-cooled lithium-lead test blanket system of ITER or DEMO, an experimental campaign was carried out with the support of the Integrated European Lead Lithium LOop experimental facility (IELLLO), installed at the ENEA Brasimone research center, Italy. The experiments were carried out by measuring the drainage time of the internal permanent magnet pump channel, normally used to circulate the LiPb in the loop, with and without the magnetic field. Moreover, this paper proposes a new numerical methodology to study the time delay induced by the MHD by using the commercial software COMSOL Multiphysics. In this way, it was possible to evaluate the LiPb fraction present at each time step in the computational domain and to estimate the time necessary for the complete drainage of the channel. The level set method was used to describe the transient behavior of the MHD flow under low-Rm approximation. The developed code was compared with the experimental results and showed good agreement, and it constitutes the first step in model validation as a possible application to ITER and DEMO. The experimental and numerical analyses performed in this work can be used as a benchmark case for MHD code development

Experimental and RELAP5-3D results on IELLLO (Integrated European Lead Lithium LOop) operation

The experimental facility IELLLO (Integrated European Lead Lithium LOop) was designed and installed at the ENEA Brasimone Research Centre to support the design of the HCLL TBM (Helium Cooled Lithium Lead Test Blanket Module).This work presents the results of the experimental campaign carried out within the framework of F4E-FPA-372 and which had three main objectives. First, to produce new experimental data for flowing LLE (Lead-Lithium Eutectic) for an analysis of the loop and the characterization of its main components. Then, to evaluate performances of commercial instrumentation as available instrumentation is not designed for use in LLE. Lastly, to use the data for validation of the model developed with the system code RELAP5-3D. The data collected could prove helpful to analyze the behavior of the LLE loop of ITER and DEMO in accidental conditions.The results show that the regenerative countercurrent heat exchanger has an efficiency ranging from 70 to 85%, mainly depending on the LLE mass flow rate. It was verified that the air cooler has the capability to keep the cold part of the loop at 623. K, even in the most demanding situation (700. rpm and maximum temperature of the hot part). The instrumentation tested showed good accuracy, with the exception of the turbine flow meter. Nevertheless, specific limitations in the upper operative temperatures were found for the LLE direct contact pressure transducer. RELAP5-3D simulations fit very well the associated experimental results achieved

On the stability of fissured slopes subject to seismic action

A set of analytical solutions achieved by the upper bound theorem of limit analysis and the pseudo-static approach is presented for the assessment of the stability of homogeneous c, ϕ slopes manifesting vertical cracks and subject to seismic action. Rotational failure mechanisms are considered for slopes with cracks of either known or unknown depth and location. A validation exercise was carried out based on numerical limit analyses and displacement-based finite-element analyses with strength reduction technique. Charts providing the stability factor for fissured slopes subject to both horizontal and vertical accelerations for any combination of c, ϕ and slope inclination are provided. The effect of the direction of the vertical acceleration on slope stability is specifically analysed. Yield seismic coefficients are also provided. When the presence of cracks within the slope can be ascertained with reasonable confidence, maps showing the zones within the slope where they have no destabilising effect are provided. Finally, Newmark's method was employed to assess the effect of cracks on earthquake induced displacements. To this end, displacement coefficients are provided in chart form as a function of the slope characteristics. Two examples of slopes subjected to known earthquakes are illustrated

Manufacturing of PAV-ONE, a Permeator against Vacuum Mock-Up with Niobium Membrane

The Permeator Against Vacuum (PAV) is one of the proposed technologies for the Tritium Extraction System of the WCLL BB (Water-Cooled Lithium-Lead Breeding Blanket) of the EU DEMO reactor. In this paper, the manufacturing of the first PAV mock-up with a niobium membrane with a cylindrical configuration is presented. This work aimed to demonstrate the possibility of manufacturing a relevant-size PAV to be later tested in the TRIEX-II facility. The adopted prototypical solutions are described in detail, starting with the methodology developed to join the Nb tubes with a 10CrMo9-10 (A182 F22) plate. Dedicated manufacturing and welding procedures, based on vacuum brazing with a nickel-based brazing alloy, were developed to solve the problem. This new kind of brazing was first analyzed to check the morphology of the joint and then tested to check its capability to withstand the TRIEX-II operative conditions. In parallel, the compatibility with a lithium-lead environment was analyzed by exposing samples of niobium and 10CrMo9-10 (A335 P22) to a flow of the eutectic alloy at 500 °C up to 4000 h. Finally, the PAV mock-up was installed in the TRIEX-II facility

Inhaled tobramycin in children with acute bacterial rhinopharyngitis.

Antibiotic abuse for treating rhinopharyngitis induces the occurrence of resistant bacteria. As topical drugs might reduce this phenomenon, the aims of our study were to evaluate inhaled tobramycin in children with acute bacterial rhinopharyngitis and to compare it with oral amoxicillin/clavulanate. The trial was conducted as randomized, parallel group and double blind. Children, aged 3–6 years, with acute bacterial rhinopharyngitis were treated with 15 mg of aerosolized tobramycin (Group A) or 50 mg/Kg of amoxicillin/clavulanate (Group B) twice daily for 10 days. The following parameters were assessed: nasal obstruction, mucopurulent rhinorrhea, post-nasal drip, adenoidal hypertrophy, tympanic inflammation, tympanogramm, rhinomanometry and cultures. Of 416 patients screened, 311 children (178 females and 133 males), median age 4.5 years, completed the study: 156 in Group A and 155 in Group B. Both treatments improved all parameters (p<0.01 for all). Intergroup analysis showed that inhaled tobramycin indu..

Status of maturation of critical technologies and systems design: Breeding blanket

The scope of the EUFOfusion Work Package Breeding Blanket is to develop a blanket concept for the EU DEMO reactor; this includes the blanket segments inside the Vacuum Vessel and the related Tritium Extraction/Removal Systems. In the Pre-Concept Design (PCD) Phase, two concepts have been selected as candidates; a solid and a liquid breeder blanket cooled with helium and water, respectively. The design of these two blanket systems has been adapted to the DEMO plant design developed in the PCD Phase and performances assessed. A large R&D programme has been implemented with the scope to evaluate different technologies for these blankets; including the development of breeders, tritium extraction and cooling technologies, and the manufacturing of the blanket system. A major milestone in the subsequent Concept Design Phase is the final selection of the blanket concept for DEMO

Labour politics and society in South Yorkshire.

This doctoral thesis looks at Labour politics and society in South Yorkshire between the start of the Second World War in September 1939 and the fall from office of the Attlee Labour Government in October 1951. While it accepts the predominating effects of national and international factors in providing challenges which Labour councils and local Labour Parties had to find solutions to - such as the effects of the Sheffield Blitz in 1940 and the need to re-plan Sheffield and the maintaining of the organisational existence of Labour Parties during the Second World War - it nevertheless examines those 'micro-historical' factors which made for the local diversity of the party in South Yorkshire. It tries to create a holistic and rounded portrait of the local Labour movement based mainly on fragmentary archival and newspaper evidence and examines current historical debates for local relevance such as whether a post-war consensus actually existed, whether popular political attitudes were radical or conservative and, whether such popular attitudes favoured or disfavoured Labour. It also looks at Marxist debates over the concept of 'Labourism' and whether Labour was narrowly culturally determined or whether other factors were equally important. Chapter One introduces the thesis. Chapter Two examines the fears over the post-war industrial future of Sheffield which took place during the Second World War within the City Council and between it and organisations like the trade unions and the Chamber of Commerce. It also looks at City Council debates over the proposed post-war regionalisation of local government and how that was prevented by a united council. This shows that the centralising tendencies of the London government could be resisted by the peripheries and that such tendencies were not inevitable. Chapter Three examines town planning in Sheffield during the Second World War after the Blitz in December 1940 provided an opportunity to create a more modem, better planned and less ugly city. The planning process is examined and the secrecy of the City Council noted at a time when the country was fighting to defend an open and democratic society from the Nazis. Chapter Three also looks at the wartime context of the acute post-war housing crisis. Chapter Four looks at the wartime Labour Party in South Yorkshire, its ebb in membership prior to 1942 and its resurgence after that date ending with an examination of the 1945 General Election in Sheffield. Chapter Five looks at local government between 1945 and 1951, examining the factors which prevented the reform of the local structure of local government, the effect on Sheffield and Rotherham Councils of the nationalisation of electricity, gas and local authority hospitals, and the attempts to implement the Butler Education Act of 1944 in South Yorkshire. Chapter Six looks at the attempts to implement the 1945 Collie town plan for Sheffield and the reasons for the lack of progress as well as at the contrasting housing records of Sheffield and Rotherham Councils. It attempts to account for the latter's better record when compared with the former. Chapter Seven looks the ideology and cultural determinants of the Labour Party in South Yorkshire between 1945 and 1951. It also examines Labour organisation noting the essential role of women as unpaid voluntary labour and contrasting it with their limited entry to local political office. Finally it looks at and comments on the municipal and general election results in Sheffield of the Labour Party between 1945 and 1951. Chapter Eight provides a conclusion