Computational Analysis of the initial stage of the accident at the Chernobyl' atomic power plant

Abagyan, A. A.; Arshavskii, I. M.; Dmitriev, V. M.; Kroshilin, A. E.; Krayushkin, A. V.; Khalimonchuk, V.

doi:10.1007/bf01123528

Cited by 10 publications

(3 citation statements)

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“…In the report of the USSR State Committee on the Utilization of Atomic Energy and in the IAEA official report, the Chernobyl nuclear accident was classified as a reactivity-induced accident (RIA) caused by a complex of factors: the physical characteristics of the reactor, the specific design features of the control elements (poor design of absorbers and non-optimal channels grid), and the unauthorized state of the reactor (USSR, 1986;IAEA, 1992). The aforementioned reports and publications (Abagyan et al, 1991;Afanas'eva et al, 1994;Fletcher et al, 1988) consider that the accident commenced after activation of the Emergency Protection System button (EPS-5), followed by a fast increase of the core temperature and a dramatic increase of neutron power and reactivity, and culminated with two explosions, the last of which destroyed the reactor (IAEA, 1992). These reports were reticent about the nature of the explosions, which presented the biggest issue of the accident.…”

Section: Chernobyl Npp Unit 4 Accidentmentioning

confidence: 99%

The key role of sample analysis in Fukushima Dai-Ichi decommissioning, debris management, and accident progression investigation

Zubekhina,

Pshenichnikov,

Nagae

et al. 2023

Front. Nucl. Eng.

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This review is an up-to-date report of the analysis of U-bearing samples from the Fukushima Daiichi Nuclear Power Station (1F). It summarizes the experience gained after previous severe nuclear accidents in the field of fuel debris analysis and the utilization of the results. Current methods of 1F sample analysis and the main results are presented with a discussion on future strategies of fuel debris analysis and the requirements for 1F decommissioning.

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Section: Chernobyl Npp Unit 4 Accidentmentioning

confidence: 99%

The key role of sample analysis in Fukushima Dai-Ichi decommissioning, debris management, and accident progression investigation

Zubekhina,

Pshenichnikov,

Nagae

et al. 2023

Front. Nucl. Eng.

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“…The data obtained suggest that the errors are substantially larger than the regression coefficients α ij . This indicates that, in our case, it is possible to use the additive approximation (2) The results of the calculations were used to assess the influence of the degree of conversion (the fraction of the reacted aluminum and iron oxides forming the sacrificial material) on the inversion of the oxide and metal phases of the core melt. The inversion condition corresponds to the intersection line of the surfaces in Fig.…”

Section: Analysis and The Choicementioning

confidence: 99%

“…Severe accidents at the TMI nuclear power plant [1] and at the fourth unit of the Chernobyl nuclear power plant [2], as well as a number of other accidents at nuclear power and special plants, have emphasized clearly that solving the problems associated with the safety of nuclear reactors determines prospects for the development of the entirety of nuclear power engineering. In this respect, the design of reliable systems for localization of a core melt and fission products in beyond design-basis accidents of tank-type watercooled nuclear reactors is an important problem in the development of nuclear power engineering within the next few years.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical modeling and analysis of the interaction between a core melt of the nuclear reactor and a sacrificial material

et al. 2005

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The problems regarding the design of a new class of materials, namely, sacrificial materials for use in devices intended for localization of a core melt of the nuclear reactor, are considered. Criteria are proposed for the proper choice of the chemical composition of a sacrificial material, as well as of the composition and microstructure of its constituents. The possible alternatives are outlined and analyzed. The results of designing a variant of the composition of sacrificial materials are presented. The experimental data on the interaction of an oxide sacrificial material with simulators of the metal and oxide phases of the core melt are discussed. A new type of combustion of materials, namely, the liquid-phase combustion, is revealed. It is demonstrated that the material designed can be used in systems intended for localization of a core melt of the nuclear reactor.

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Analysis of the chernobyl accident taking core destruction into account

Afanas'eva¹,

Fedosov²,

Donderer³

et al. 1994

At Energy

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Computer modeling of neutron-physical and thermohydraulic processes has been used extensively in the analysis of the Chernobyl accident. In most works the first phase of the accident (up to the moment of destruction of the fuel) is studied. These studies have revealed serious deficiencies of RBMK reactors that resulted in a nonroutine state with catastrophic consequences during operation: a large positive steam reactivity coefficient and a defect in the construction of the control rods, specifically, the possibility of a reactivity increase as a result of displacement of water to the core bottom when the safety and control rods are inserted in the process of stopping the reactor. The important role of the last factor has been noted in many investigations [1][2][3]. In some works [4-6] a large power burst was obtained during modeling, neglecting the effect of the rods, as a result of other external actions, for example, cavitation. Calculations performed using three-dimensional neutron-thermohydraulic programs with maximum use of accessible initial information have shown that both factors are important [1, 7]. If one of them is artificially excluded, it is impossible to obtain the power burst which explains the explosion.The hypothesis of a second neutron power burst has not been adequately proved. Starting with the first report [8], it has been shown in some works that a second, more powerful burst occurred -1 sec after the first burst. We note that the existence of two bursts is characteristic, as a rule, for calculations which employ the simplest (point, one-dimensional) models [4, 6, 9, 10].The second phase of the accident, associated with the destruction of the fuel elements, has been studied much less. Analysis of the destructive forces on the basis of experiments on impulsive irradiation of fuel elements at NSRR is presented in [l 1]. A scenario of the accident from the first power burst up to burning of the graphite is described in [12]. The key point is the dispersing of the fuel, i.e., rapid destruction of the fuel into small particles. The effect of destructive processes on the reactivity and the neutron power has not been considered.The effect of a change in the fuel geometry on the reactivity was studied in [6, 13, i4]. It was shown that under certain conditions destruction of the fuel can result in an increase of reactivity. One variant is rapid cooling of the dispersed fuel in water. As a result of the Doppler effect, the reactivity associated with boiling of the coolant is added to the positive reactivity. Moreover, for a dried channel with dispersed fuel, a decrease in the amount of fuel to 60-65 % of the initial amount results in a positive reactivity exceeding 1/3 [6], where/3 is the effective fraction of delayed neutrons.Computational analysis of the accident at the fuel destruction stage requires a complicated model which includes a three-dimensional description of the neutron-physical, thermohydraulic, thermomechanical, and chemical processes in the core taking into account their couplings. A...

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Computational Analysis of the initial stage of the accident at the Chernobyl' atomic power plant

Cited by 10 publications

References 0 publications

The key role of sample analysis in Fukushima Dai-Ichi decommissioning, debris management, and accident progression investigation

The key role of sample analysis in Fukushima Dai-Ichi decommissioning, debris management, and accident progression investigation

Physicochemical modeling and analysis of the interaction between a core melt of the nuclear reactor and a sacrificial material

Analysis of the chernobyl accident taking core destruction into account

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