Method for establishing three-dimensional solving model of migration time of N16 nuclide on secondary side of steam generator

Abstract

The invention discloses a method for establishing a three-dimensional solving model of migration time of N16 nuclide on a secondary side of a steam generator. The method is suitable for three-dimensional calculation of radionuclide migration time and primary side coolant leakage amount in the process that coolant with N16 nuclide on the primary side leaks and migrates to a secondary side nuclide monitoring point under the working condition that a heat transfer pipe of a nuclear power system steam generator is damaged. The establishment of the numerical calculation model mainly comprises the following steps of: 1, performing geometric simplification of the steam generator and establishment of a three-dimensional geometric model; 2, dividing calculation nodes on two sides of the steam generator; 3, establishing a transient three-dimensional thermal hydraulic calculation model of the steam generator; 4, determining N16 nuclide concentration at leakage positions of a heat transfer tube anda leakage part; 5, carrying out N16 nuclide migration time tracking and N16 nuclide decay migration model development; and 6, iteratively calculating the migration time of the N16 nuclide from the leakage point to a nuclide monitoring position, deriving to obtain the leakage amount of a coolant according to the nuclide migration time and the specific activity, and predicting a rupture position through the crevasse leakage amount.

Description

technical field [0001] The invention relates to the technical field of damage detection of heat transfer tubes of steam generators in nuclear power systems, in particular to a method for establishing a three-dimensional solution model for the migration time of N16 nuclides on the secondary side of the steam generator. Background technique [0002] The steam generator is a large-scale heat exchange equipment in the nuclear power system. Its operating conditions are harsh. The heat transfer tube wall with a thickness of 1 mm separates the primary and secondary loops. The primary side is a high-temperature, high-pressure radioactive coolant, and the secondary loop is driven by natural circulation. The two-phase flow of the two-phase flow, the water quality of the secondary circuit contains more impurities, and more corrosive dirt and impurities are easy to accumulate on the tube bundle support plate, the outer wall of the heat transfer tube and the bottom tube sheet. The heat t...

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Problems solved by technology

[0015] The main purpose of the present invention is to aim at the defects of existing calculation models of N16 nuclides in the secondary circuit migration time in the field of nuclear power technology, and adopt a transient three-dimensional computational fluid dynamics method to establish a set of three-dimensional flow field on the secondary side. The impact of the migration time, and the numerical solution model of the N16 nuclide migration time on the secondary side of the steam generator that can fully consider the decay phenomenon of the radionuclide in the secondary side migration process, this calculation model can effectively reduce the The impact of the one-dimensional simplification process on the calculation accuracy can fully consider the impact of the nuclide decay process on its migration time on the secondary side. Secondly, the geometry of the heat transfer tube bundle in the present invention is not simplified, and the tube bundle area can be fully considered Conditions of rupture of heat transfer tubes at various positions

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