Reconstructing the axial void velocity profile in BWRS from measurements of the in-core neutron noise
Paper i proceeding, 2020

The problem of determining the axial velocity profile from the in-core neutron noise measurements is revisited, with the purpose of developing an objective method for the determination of the void fraction. Until now it was assumed that in order to determine a realistic velocity profile which shows an inflection point and hence has to be at least a third order polynomial, one needs four transit times and hence five in-core detectors at various axial elevations. However, attempts to determine a fourth transit time by adding a TIP detector to the existing four LPRMs and cross-correlate it with any of the LPRMs were unsuccessful so far. In this paper we thus propose another approach, where the TIP detector is only used for the determination of the axial position of the onset of boiling. By this approach it is sufficient to use only three transit times. Moreover, with another parametrisation of the velocity profile, it is possible to reconstruct the velocity profile even without knowing the onset point of boiling, in which case the TIP is not needed. In the paper the principles are explained and the strategy is demonstrated by concrete examples.

BWR

Void velocity profile

Transit time

Neutron noise

Författare

Imre Pazsit

Chalmers, Fysik, Subatomär fysik och plasmafysik

Mathieu Hursin

Paul Scherrer Institut

Ecole Polytechnique Federale de Lausanne (EPFL)

Henrik Nylén

Ringhals AB

Victor Dykin

Chalmers, Fysik, Subatomär fysik och plasmafysik

International Conference on Physics of Reactors: Transition to a Scalable Nuclear Future, PHYSOR 2020

Vol. 2020-March 211-218

2020 International Conference on Physics of Reactors: Transition to a Scalable Nuclear Future, PHYSOR 2020
Cambridge, United Kingdom,

Ämneskategorier

Acceleratorfysik och instrumentering

Medicinsk laboratorie- och mätteknik

Signalbehandling

DOI

10.1051/epjconf/202124702013

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Senast uppdaterat

2021-06-29