%0 Unpublished work %T Computation of Bias on Measured $\alpha_p$ by Monte-Carlo Simulation %+ Laboratoire de Dosimétrie, de Contrôle-commande et Instrumentation (LDCI) %+ CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)) %A Boffy, R. %A Jammes, C. %8 2020-04-27 %D 2020 %K Nuclear reactor %K kinetic parameters %K alpha %K Monte-Carlo %Z Physics [physics]/Nuclear Experiment [nucl-ex]Preprints, Working Papers, ... %X Controlling the reactivity of a nuclear reactor requires the knowledge of its kinetic parameters. Even though they can be computed by neutronic codes, they often have to be measured to finish the commissioning of a new installation. Amongst the list of kinetic parameters, we are specifically interested in the prompt-decay constant ($\alpha_p$). In practice, the presence of a reflector generates a decay constant, which will differ from core's $\alpha_p$ , and that might disturb the measurement of the whole set of kinetic parameters. Such a behaviour is a drawback for experimentalists since neutron detectors are usually located in non-fissile areas. The aim of the study is to give numerical estimates of the bias that can come out when measuring kinetic parameters of a light-water nuclear reactor. The work is based on on time-impulse techniques to derive kinetic parameters from the flux decay of the system. The impact of the detector position, as well as the reactivity level have been studied in a concurrent way. As an example, it was shown that $\alpha_p$ could be underestimated by a factor ranging from 8 to 12 % in a case of a sub-criticality of −3600 pcm, if the detector was located in the core or the reflector, respectively. %G English %2 https://cea.hal.science/cea-02555090/document %2 https://cea.hal.science/cea-02555090/file/201700003816.pdf %L cea-02555090 %U https://cea.hal.science/cea-02555090 %~ CEA %~ DSV %~ DEN %~ CEA-DRF %~ DEN-CAD %~ CEA-CAD