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[en] The pre-conceptual design phase confirmed the safety potential of the CFV cores and the CFV concept is retained for conceptual design phase. Its potential will have to be consolidated by: • characterising the core behaviour in all the operating conditions (categories 1 to 4 and severe accident prevention situations); • selecting and designing the additional safety measures in relation to prevention and mitigation situations; • reinforcing the studies related to severe accident mitigation situations
[en] We study the impact that uncertainties on assumed relations between galaxy bias parameters have on constraints of the local PNG fNL parameter. We focus on the relation between the linear density galaxy bias and local PNG bias in an idealized forecast setup with multitracer galaxy power spectrum and bispectrum data. We consider two parametrizations of galaxy bias: 1) one inspired by the universality relation where and is a free parameter; and 2) another in which the product of bias parameters and fNL, like fNL bφ, is directly fitted for. The constraints on the fNL−p plane are markedly bimodal, and both the central value and width of marginalized constraints on fNL depend sensitively on the priors on . Assuming fixed in the constraints with a fiducial value of can bias the inferred fNL by to ; priors around this fiducial value are however sufficient in our setup to return unbiased constraints. In power spectrum analyses, parametrization 2, that makes no assumptions on , can distinguish fNL ≠ 0 with the same significance as parametrization 1 assuming perfect knowledge of (the value of fNL is however left unknown). A drawback of parametrization 2 is that the addition of the bispectrum information is not as beneficial as in parametrization 1. Our results motivate strongly the incorporation of mitigation strategies for bias uncertainties in PNG constraint analyses, as well as further theoretical studies on the relations between bias parameters to better inform those strategies.
[en] This paper summarises the Westinghouse approach to Accident Management, both preventive and mitigative, and reviews the scope and some results of the VVER studies. It also identifies future work that would be needed to implement plant specific Severe accident management guidance at VVER plant (author)