Dizajn i proračun mehaničkog čepa za čepljenje cijevi parogeneratora

master's thesis

• Title (english): Stress analysis of plugging procedure at PWR nuclear power plant steam generator
• Author: Ana Obradović
• Mentor: Igor Karšaj (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2016-12-09, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

Cijevi parogeneratora primarnog kruga nuklearnih elektrana PWR tipa (eng. Pressurized Water Reactor), podložne su periodičkom ispitivanju metodom nerazornih ispitivanja, a cilj tog ispitivanja je provjera cjelovitosti cijevne stijenke kako bi se spriječilo curenje radioaktivnog medija iz primarnog kruga u sekundarni krug. Ako se pronađeno oštećenje procijeni kao kritično, potrebno je provesti korektivne aktivnosti čepljenja oštećene cijevi, te se oštećena cijev uklanja iz upotrebe dok se oštećenje ne sanira. U ovoj vrsti parogeneratora dopušteno je začepiti najviše trećinu ukupnog broja cijevi, kako bi parogenerator još uvijek zadržao svoju punu funkcionalnost. Trenutno na tržištu postoje tri vrste čepova: mehanički, rolani i zavareni čep. Tehnologija mehaničkog čepa uspješno se primjenjuje na PWR tipovima parogeneratora koji imaju unutrašnji promjer cijevi .

U ovome radu je bilo potrebno najprije dobiti numeričku simulaciju postupka čepljenja cijevi postojećim mehaničkim čepom promjera , te na temelju spomenutog mehaničkog čepa dizajnirati mehanički čep promjera . Geometrija mehaničkog čepa modelirala se na način da su se dimenzije manjeg čepa razmjerno povećale. Usporedbom iznosa naprezanja na kontaktnim površinama mehaničkih čepova i cijevi, donio se zaključak o dizajnu mehaničkog čepa promjera . Numerički proračun se proveo u programskom paketu Abaqus/ Standard.

Provedena je verifikacija odabranog izoparametarskog heksaedarskog konačnog elementa drugog reda sa reduciranom integracijom, oznake C3D20R na jednostavnom primjeru gibanja tijela po podlozi, te su uspeređena analitička i numerička rješenja, a nakon toga se išlo u razradu zadane teme.

Abstract (english)

Tube steam generator primary circuit of nuclear power plants PWR type (Pressurized Water Reactor), are subject to periodic testing method of non-destructive testing, and the objective of this test is to check the integrity of the pipe wall to prevent leakage of radioactive media from the primary circuit into the secondary circuit. If found damage assessed as critical, it is necessary to implement corrective actions vaccination damaged pipes, and damaged pipe will be removed from service until the damage is not rehabilitated. In this type of steam generator is allowed to clog up one third of the total number of tubes to the steam generator still maintained its full functionality. Currently on the market there are three types of caps: mechanically, rolling and welded plug. Technology mechanical plug has been successfully applied to the PWR type of steam generator with an 13 mm inside diameter of the pipe.

In this Thesis, it was first necessary to obtain the numerical simulation of the process of vaccination pipes existing mechanical plug with the diameter 13 mm, and based on that, task was to design mechanical plug with diameter 16 mm. The geometry of the mechanical plug modeled in such a way that the size of the smaller plug proportionally increased. By comparing the amount of stress on the contact surfaces of mechanical plugs and pipes, brought to a conclusion about the design of the mechanical plug diameter 16 mm. The numerical calculation was conducted in the software package Abaqus / Standard.

We conducted a verification of the selected isoparametric prismatic final elements of the second row with reduced integration, marking C3D20R the simple example of motion of the body on the substrate, and are comared analytical and numerical solutions, and then they went into the development of the given topic.

• Keywords: PWR; metoda nerazornih ispitivanja; mehanički čep; C3D20R; Abaqus/ Standard
• Keywords (english): PWR; method of non-destructive testing; mechanical plug; C3D20R; Abaqus / Standard
• Language: croatian
• URN:NBN: urn:nbn:hr:235:015350
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-05-22 18:23:13