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- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Journeau, C., et al.
(författare)
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European Research on the Corium issues within the SARNET network of excellence
- 2008
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Ingår i: International Conference on Advances in Nuclear Power Plants, ICAPP 2008. - 9781605607870 ; , s. 1172-1181
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Konferensbidrag (refereegranskat)abstract
- Within SARNET, the corium topic covers all the behaviors of corium from early phase of core degradation to in or ex-vessel corium recovery with the exception of corium interaction with water, direct containment heating and fission product release. The corium topic regroups in three work packages the critical mass of competence required to improve significantly the corium behavior knowledge. The spirit of the SARNET networking is to share the knowledge, the facilities and the simulation tools for severe accidents, so to reach a better efficiency and to rationalize the R&D effort at European level. Extensive benchmarking has been launched in most of the areas of research. These benchmarks were mainly dedicated to the recalculation of experiments, while, in the next periods, a larger focus will be given to integral experiments or reactor applications. Eventually, all the knowledge will be accumulated in the ASTEC severe accident simulation code through physical model improvements and extension of validation database. This paper summarizes the progress that has been achieved in the frame of the networking activities. A special focus is placed on the melt pool and debris coolability and corium-concrete interaction, in which, the effects due to multidimensional geometries and heterogeneities has been shown, during SARNET, to play a crucial role and for which further research is still needed.
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| 3. |
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| 4. |
- Van Dorsselaere, J.P., et al.
(författare)
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ASTEC extension to other reactor types than Generation II PWR
- 2008
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Ingår i: Proc. of ERMSAR 2008.
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Konferensbidrag (refereegranskat)abstract
- The initial IRSN-GRS requirements for the development of the ASTEC European integral codecovered all present and future PWR, VVER and BWR. After 4 years and a half of SARNET activities, theASTEC V1 code is fully applicable to all severe accident scenarios, at power operation, in Gen.II PWR andVVER. Partners performed substantial code assessment tasks on both VVER-440 and 1000 with good resultson validation (such as PACTEL) and benchmarking with other codes on plant sequences.In the frame of preparation of the new series of ASTEC V2 versions that will account for the needs ofevolution expressed by the SARNET partners, the extension to Gen.III PWR is under way. The 1stversionV2.0, planned for march 09, will be applicable to the EPR, in particular its external core-catcher and to newPWR designs with In-Vessel Melt Retention (IVMR), the latter thanks to CEA work. IVS calculations onVVER-440/V213 showed the ASTEC V1 capabilities to evaluate the IVMR possibilities: these capabilitieswill be improved in the future through a coupled analysis of in-vessel corium and cavity cooling circuit.For BWR applications, the KTH ranking of needs of model adaptations was reviewed by GRS. Theseadaptations mainly concern the Reactor Cooling System (RCS) thermal-hydraulics (internal pumps, drier,separator...) and the core degradation (canisters, control rod guide tubes, penetrations in lower head...). Forcore degradation, the scoping application test on the CORA-18 experiment using the current ASTEC V1models (for adaptation to absorber blades and canisters) showed promising results. The GRS benchmark withthe COCOSYS GRS code showed the applicability of the CPA containment module. For ex-vesselphenomena, the only missing model is the formation of a debris bed during corium slump from lower headinto a flooded cavity after lower head failure and its coolability/erosion behaviour with core concreteinteraction under flooded conditions. All other current V1 models can be used, sometimes with minoradaptations or further need of validation, as for iodine behaviour in containment at temperatures up to 1000Kand the possible decomposition of metal iodides to gaseous iodine at these high temperatures in atmosphere.Detailed specifications will be written soon to prepare the development and validation task planned inSARNET2 with the same partners.For CANDU reactors applications, the priority concerns the core degradation due to the peculiarity ofthe vessel geometry (horizontal core, pressure tubes, calandria...). The exploratory plant applications haveshown that all other current models can be used but tests are still necessary to conclude on models of PHT(Primary Heat Transfer) thermal-hydraulics. INR work takes benefit of the AECL knowledge of MAAP4-CANDU models. A significant benefit is foreseen from the BARC (India) work on core degradation modelsin the frame of IRSN-BARC bilateral collaboration.
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