We study axial core oscillations due to xenon poisoning in thermal neutron nuclear reactors with simple 1D models: a linear one-group model, a linear two-group model, and a non-linear model taking the Doppler effect into account. | Modeling and control of xenon oscillations in thermal neutron reactors EPJ Nuclear Sci. Technol. 6 48 2020 Nuclear Sciences B. Mercier et al. published by EDP Sciences 2020 amp Technologies https epjn 2020009 Available online at https REGULAR ARTICLE Modeling and control of xenon oscillations in thermal neutron reactors Bertrand Mercier1 Zeng Ziliang2 Chen Liyi2 and Shao Nuoya2 1 CEA INSTN 91191 Gif sur Yvette France 2 Institut Franco-Chinois de l Energie Nucléaire Sun Yat-sen University 519082 Zhuhai Campus Guangdong Province . China Received 18 November 2019 Received in final form 3 March 2020 Accepted 12 March 2020 Abstract. We study axial core oscillations due to xenon poisoning in thermal neutron nuclear reactors with simple 1D models a linear one-group model a linear two-group model and a non-linear model taking the Doppler effect into account. Even though nuclear reactor operators have some 3D computer codes to simulate such phenomena we think that simple models are useful to identify the sensitive parameters and study the efficiency of basic control laws. Our results are that for the one-group model if we denote the migration area by M2 and by H the height of the core the sensitive parameter is H M. H being fixed for the 2 groups model there are still 2 sensitive parameters the first one being replaced by M 21 þ M 22 where M 21 denotes the migration area for fast neutrons and M 22 the migration area for thermal neutrons. We show that the Doppler effect reduces the instability of xenon oscillations in a significant way. Finally we show that some proportional integral derivative PID feedback control law can damp out xenon oscillations in a similar way to the well-known Shimazu control law Y. Shimazu Continuous guidance procedure for xenon oscillation control J. Nucl. Sci. Technol. 32 1159 1995 . The numerical models described in our paper have been applied to PWR. 1 Introduction the latter it seems possible to prove theoretical .
