Thermo-hydraulic behaviour of coolant in nuclear reactor VVER-440 under reactor pool filling conditions

2021 ◽  
Author(s):  
Juraj Paulech ◽  
Justín Murín ◽  
Vladimír Kutiš ◽  
Gabriel Gálik
Keyword(s):  
Nuclear Reactor ◽  
Hydraulic Behaviour ◽  
Reactor Pool

scholarly journals International Standard Problems and Small Break Loss-of-Coolant Accident (SBLOCA)

2008 ◽  
Vol 2008 ◽  
pp. 1-22 ◽  
Author(s):  
N. Aksan
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Lessons Learned ◽  
Reactor Safety ◽  
Hydrogen Distribution ◽  
Integral Test ◽  
International Standard ◽  
Hydraulic Behaviour ◽  
Nuclear Reactor Safety

Best-estimate thermal-hydraulic system codes are widely used to perform safety and licensing analyses of nuclear power plants and also used in the design of advance reactors. Evaluation of the capabilities and the performance of these codes can be accomplished by comparing the code predictions with measured experimental data obtained on different test facilities. OECD/NEA Committee on the Safety of Nuclear Installations (CSNI) has promoted, over the last twenty-nine years, some forty-eight international standard problems (ISPs). These ISPs were performed in different fields as in-vessel thermal-hydraulic behaviour, fuel behaviour under accident conditions, fission product release and transport, core/concrete interactions, hydrogen distribution and mixing, containment thermal-hydraulic behaviour. 80% of these ISPs were related to the working domain of principal working group no.2 on coolant system behaviour (PWG2) and were one of the major PWG2 activities for many years. A global review and synthesis on the contribution that ISPs have made to address nuclear reactor safety issues was initiated by CSNI-PWG2 and an overview on the subject of small break LOCA ISPs is given in this paper based on a report prepared by a writing group. In addition, the relevance of small break LOCA in a PWR with relation to nuclear reactor safety and the reorientation of the reactor safety program after TMI-2 accident are shortly summarized. The experiments in four integral test facilities, LOBI, SPES, BETHSY, ROSA IV/LSTF and the recorded data during a steam generator tube rupture transient in the DOEL-2 PWR (Belgium) were the basis of the five small break LOCA related ISP exercises, which deal with the phenomenon typical of small break LOCAs in Western design PWRs. Some lessons learned from these small break LOCA ISPs are identified in relation to code deficiencies and capabilities, progress in the code capabilities, possibility of scaling, and various additional aspects. ISPs are providing unique material and benefits for some safety-related issues.

Core Ignition Prediction With Moving Two-Phase Zone Boundaries

2008 ◽  
Author(s):  
Dov Hasan ◽  
Yuri Nekhamkin ◽  
Eitan Wacholder ◽  
Ezra Elias
Keyword(s):  
Nuclear Reactor ◽  
Reactor Core ◽  
Phase Region ◽  
Transient Temperature ◽  
Phase Zone ◽  
Two Phase ◽  
Loss Of Coolant Accident ◽  
Hydraulic Behaviour ◽  
Nuclear Reactor Core ◽  
Accident Conditions

The interaction between a fuel rod metal clad and the surrounding steam in a nuclear reactor core under hypothetical accident conditions is considered using a thermal balance based model. This enables the calculation of the metal transient temperature and its rate of oxidation, which may possibly lead to ignition and rapid burning. The transient fluid thermal-hydraulic behaviour of the two phase region, as well as the propagation in space and time of its boundaries following a step change in the coolant inlet mass flow rate are solved using a one-dimensional, two-phase homogeneous flow model. The solution scheme consists of first solving the velocity field analytically followed by a numerical solution of the remaining balance equations for the density field. The transient location of the dry-zone region, as well as the other flow primary variables; i.e., vapour quality, and enthalpy are then directly obtained. Numerical results are illustrated based on input data of a partially uncovered AP600 type nuclear reactor core during a bottom-reflooding phase of a loss of coolant accident scenario.

scholarly journals Thermo-Hydraulic Behaviour of Coolant in Nuclear Reactor VVER-440 Under Refuelling Conditions

2017 ◽  
Vol 67 (1) ◽  
pp. 87-92
Author(s):  
Juraj Paulech ◽  
Vladimír Kutiš ◽  
Gabriel Gálik ◽  
Jakub Jakubec ◽  
Tibor Sedlár
Keyword(s):  
Numerical Simulation ◽  
Pressure Vessel ◽  
Nuclear Reactor ◽  
Reactor Pressure Vessel ◽  
Spent Fuel ◽  
Storage Pool ◽  
Hydraulic Behaviour ◽  
Fuel Storage ◽  
Heating Up ◽  
Reactor Pressure

Abstract The paper presents the numerical simulation of thermo-hydraulic behaviour of coolant in the VVER- 440 nuclear reactor under standard outage conditions. Heating-up and flow of coolant between the reactor pressure vessel and spent fuel storage pool are discussed.

In situ TEM studies of irradiation effects for materials improvement

1991 ◽  
Vol 49 ◽  
pp. 452-453
Author(s):  
Charles W. Allen
Keyword(s):  
Nuclear Reactor ◽  
Austenitic Stainless Steels ◽  
High Energy ◽  
Point Of View ◽  
In Situ Tem ◽  
Irradiation Effects ◽  
Tem Analysis ◽  
Radiation Induced ◽  
Analytical Tools

Irradiation effects studies employing TEMs as analytical tools have been conducted for almost as many years as materials people have done TEM, motivated largely by materials needs for nuclear reactor development. Such studies have focussed on the behavior both of nuclear fuels and of materials for other reactor components which are subjected to radiation-induced degradation. Especially in the 1950s and 60s, post-irradiation TEM analysis may have been coupled to in situ (in reactor or in pile) experiments (e.g., irradiation-induced creep experiments of austenitic stainless steels). Although necessary from a technological point of view, such experiments are difficult to instrument (measure strain dynamically, e.g.) and control (temperature, e.g.) and require months or even years to perform in a nuclear reactor or in a spallation neutron source. Consequently, methods were sought for simulation of neutroninduced radiation damage of materials, the simulations employing other forms of radiation; in the case of metals and alloys, high energy electrons and high energy ions.

Eds Of Radioactive Particles By Self-Induced Fluorescence

1990 ◽  
Vol 48 (2) ◽  
pp. 238-239
Author(s):  
Gregory L. Finch ◽  
Richard G. Cuddihy
Keyword(s):  
Electron Beam Irradiation ◽  
Nuclear Reactor ◽  
X Rays ◽  
Reactor Accident ◽  
Internal Radiation ◽  
X Ray ◽  
External Sources ◽  
X Irradiation ◽  
Available Information ◽  
Individual Particles

The elemental composition of individual particles is commonly measured by using energydispersive spectroscopic microanalysis (EDS) of samples excited with electron beam irradiation. Similarly, several investigators have characterized particles by using external monochromatic X-irradiation rather than electrons. However, there is little available information describing measurements of particulate characteristic X rays produced not from external sources of radiation, but rather from internal radiation contained within the particle itself. Here, we describe the low-energy (< 20 KeV) characteristic X-ray spectra produced by internal radiation self-excitation of two general types of particulate samples; individual radioactive particles produced during the Chernobyl nuclear reactor accident and radioactive fused aluminosilicate particles (FAP). In addition, we compare these spectra with those generated by conventional EDS.Approximately thirty radioactive particle samples from the Chernobyl accident were on a sample of wood that was near the reactor when the accident occurred. Individual particles still on the wood were microdissected from the bulk matrix after bulk autoradiography.

Becoming the Nuclear-Front-End

2017 ◽  
Vol 47 (189) ◽  
Author(s):  
Patrick Schukalla
Keyword(s):  
Nuclear Reactor ◽  
Chemical Elements ◽  
High Technology ◽  
Power Production ◽  
Uranium Mining ◽  
Nuclear Industry ◽  
Current State ◽  
Front End ◽  
Production And Consumption ◽  
Uranium Exploration

Uranium mining often escapes the attention of debates around the nuclear industries. The chemical elements’ representations are focused on the nuclear reactor. The article explores what I refer to as becoming the nuclear front – the uranium mining frontier’s expansion to Tanzania, its historical entanglements and current state. The geographies of the nuclear industries parallel dominant patterns and the unevenness of the global divisions of labour, resource production and consumption. Clearly related to the developments and expectations in the field of atomic power production, uranium exploration and the gathering of geological knowledge on resource potentiality remains a peripheral realm of the technopolitical perceptions of the nuclear fuel chain. Seen as less spectacular and less associated with high-technology than the better-known elements of the nuclear industry the article thus aims to shine light on the processes that pre-figure uranium mining by looking at the example of Tanzania.

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