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Evaluation method for defects of CPR1000 unit reactor pressure vessel core cylindrical shell zones

A technology for pressure vessels and reactors, applied in reactors, nuclear reactor monitoring, reduction of greenhouse gases, etc., can solve problems such as the impact on the safe operation of nuclear power plants

Active Publication Date: 2013-10-23
SUZHOU NUCLEAR POWER RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, RPV may have defects in the process of manufacturing, installation and service, and these factors will have an impact on the safe operation of nuclear power plants

Method used

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  • Evaluation method for defects of CPR1000 unit reactor pressure vessel core cylindrical shell zones
  • Evaluation method for defects of CPR1000 unit reactor pressure vessel core cylindrical shell zones
  • Evaluation method for defects of CPR1000 unit reactor pressure vessel core cylindrical shell zones

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0068] (1) Defect characterization

[0069] There are axial cracks on the axial inner surface of the RPV core barrel, the crack depth a=19.945mm, and the defect length 2c=119.67mm.

[0070] (2) Determine material properties

[0071] RPV material is steel 16MND5. See RCCM specification for material properties. The fracture toughness of the material is taken as the fracture toughness value of the material given in Appendix ZG of the RCCM Code, and the ductile-brittle transition temperature NDT RT is taken as 20°C.

[0072] (3) Load analysis and classification

[0073] Assuming that the evaluated transient is a cold shutdown transient, the pressure and temperature in the RPV change with time as shown in Table 1. The RPV core barrel bears the internal pressure load and the thermal stress load caused by the cooling process, where the internal pressure load It belongs to the primary load, and the thermal stress load is the secondary stress load.

[0074] Table 1 Pressure and te...

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PUM

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Abstract

The invention provides an evaluation method for defects of CPR1000 unit reactor pressure vessel core cylindrical shell zones. The method comprises steps of (1) characterizing defects; (2) acquiring physical property parameters and breaking property parameters of a material; (3) analyzing and classifying loads; (4) selecting a failure evaluation curve; (5) calculating evaluation point coordinates; (6) drawing evaluation points and evaluating safety; and (7) evaluating a structure safety allowance and analyzing parameter sensitivity. The method has advantages comprising higher precision, lower calculation cost and capability of giving selection principles of the safety allowance in the evaluation over the prior art, and therefore the method has practical significance for safety evaluation of defects of core cylindrical shell zones.

Description

technical field [0001] The invention belongs to the technical field of structural integrity assessment, and specifically relates to an accurate safety assessment method for crack-like defects in the core section of the reactor pressure vessel (RPV) of a CPR1000 unit. The safety assessment method under transient conditions provides an accurate technical basis for the safety assessment of key nuclear power equipment. Background technique [0002] Due to the influence of factors such as raw materials, processing and use, large-scale engineering structures used in the nuclear power field often have different types of defects inside the structure, such as inclusions, welding defects and cracks. The existence of defects will directly endanger the integrity of the structure (or called the use of security). If the impact of defects on structural integrity is underestimated, it may lead to major accidents such as equipment damage and casualties; and if the harmful effects of defects...

Claims

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Application Information

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IPC IPC(8): G21C17/00
CPCY02E30/30
Inventor 任爱吕峰陈明亚刘向兵王荣山黄平彭啸
Owner SUZHOU NUCLEAR POWER RES INST
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