An axial xenon oscillation model

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 M 2 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 M12+M22 where M12 denotes the migration area for fast neutrons and M22 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.

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“…A lot of publications can be found in the literature on the problem of xenon oscillations in nuclear reactors [1][2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…The core is assumed to be homogenized so that, in each cm 3 of core, there are v cm 3 of fuel and (1 À v) cm 3 of moderator. In a PWR we have v ∼ 1/3 so that the moderation ratio…”

Section: Introduction Of Iodine and Xenonmentioning

confidence: 99%

Modeling and control of xenon oscillations in thermal neutron reactors

Mercier¹,

Ziliang

Chen

et al. 2020

EPJ Nuclear Sci. Technol.

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“…where ν is fission neutron multiplicity, and X 0 is the reference (steady-state) 135 Xe concentration. Space-time oscillations of the 135 Xe concentration, imprecisely also referred to simply as "xenon oscillations", are a well-known phenomenon which might also occur during or after other, nonload-following, transients (Gyorey, 1962;Lellouche, 1962;Randall and John, 1962;Shotkin and Abernathy, 1963;Christie and Poncelet, 1973;Bauer and Poncelet, 1974;El-Bassioni and Poncelet, 1974;Onega and Kisner, 1978;Schulz and Lee, 1980;Kobayashi and Yoshikuni, 1982;Moon and Han, 1982;Teachman and Onega, 10.3389/fenrg.2023.1111357 1983; Gondal and Axford, 1986;Berkan et al, 1991;Alten and Danofsky, 1993;Shimazu, 1995;Tiwari et al, 1996;Song and Cho, 1997;Song et al, 1999;Domingos et al, 2003;Marseguerra et al, 2003;Obaidurrahman and Doshi, 2011;Chang, 2016;Pradhan et al, 2016;Zarei et al, 2016). Whereas principles regarding the neutron kinetics are the same for the load-following operations, the objective functions for the control methods differ-typically, axial offsets of the thermal power density, 135 Xe and 135 I concentrations are observed.…”

Section: Feedback From 135 Xe Build-upmentioning

confidence: 99%

“…In the past, load following capabilities of nuclear reactors have been studied in numerous references, which are reviewed in the main part of this paper. They mostly rely on single point kinetics (Aboanber et al, 2014;Arab-Alibeik and Setayeshi, 2005;Ben-Abdennour et al, 1992;Edwards et al, 1990;Elsisi and Abdelfattah, 2020;Hui et al, 2020;Hui and Yuan, 2021;2022c;d;Khajavi et al, 2002;Khorramabadi et al, 2008;Li and Zhao, 2013a;b, 2014;Liu and Wang, 2014;Mousakazemi, 2019;Nair and Gopal, 1987;Park and Cho, 1992;Torabi et al, 2011;Wang et al, 2019;Zarei et al, 2016) or multi-point kinetics (Ansarifar and Saadatzi, 2015;Eliasi et al, 2011;Hui and Yuan, 2022a;b;Kobayashi and Yoshikuni, 1982;Li, 2014a;b;Li et al, 2014b;Marseguerra et al, 2003;Na et al, 1998b;a;Na, 2001;Onega and Kisner, 1978;Parhizkari et al, 2015;Pradhan et al, 2016;Saadatzi and Ansarifar, 2017;Shimazu, 1995;Winokur and Tepper, 1984;Yadav et al, 2018) or on 1D time-dependent diffusion codes (Christie and Poncelet, 1973;…”

Section: Introductionmentioning

confidence: 99%

An overview of power reactor kinetics and control in load-following operation modes

et al. 2023

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Previous work done on reactor kinetics and control in load-following operation modes available in open literature is reviewed. The analysis is focused on, however not limited to pressurized water reactors. Different approximations of the time-dependent neutron transport problem as well as different control algorithms are described in detail and compared. Due to lack of published information the majority of the comparisons was done on qualitative level. In order to facilitate future testing and intercomparisons of models and algorithms, two so-called reference scenarios with time-dependent power demand are defined: a scenario to test the limitations of the load-following capabilities of the nuclear facilities and a second, quasi-realistic scenario.

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“…Usually, the nodal method is used for linearized equation. Onega & Kisner' 6 ' derived one-dimensional nonlinear equation of one energy group by assuming the mode of oscillation for the analysis of nonlinear oscillation of pressurized water reactor by the variational method. The present two-point coupled reactor equations without linearized approximation may be also used for the analysis of such nonlinear problems.…”

Section: Introduction 107mentioning

confidence: 99%

Analysis of xenon oscillation by coupled reactor model.

Kobayashi

Yoshikuni

1982

J. Nucl. Sci. Technol.

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Two-point coupled reactor equations are derived for the analysis of stability of xenon oscillation of coupled thermal reactor by the nodal method with use of Green's function. A simple formula for the stability criteria is obtained as a function of coupling coefficient. As coupling coefficient becomes smaller, xenon oscillation becomes more unstable as expected. Some numerical examples for a coupled slab reactor are given. The present method may be used also for usual thermal reactors by regarding them as coupled reactors by dividing them into appropriate two regions.

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An axial xenon oscillation model

Cited by 25 publications

References 5 publications

Modeling and control of xenon oscillations in thermal neutron reactors

Modeling and control of xenon oscillations in thermal neutron reactors

An overview of power reactor kinetics and control in load-following operation modes

Analysis of xenon oscillation by coupled reactor model.

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