Prediction of Axial and Radial Creep in Pressure Tubes

Proposal for a Coordinated Research Project:

Prediction of Axial and Radial Creep in Pressure Tubes

Patricia B.Bozzano - ARGENTINA Vienna, july 2013

Embalse Nuclear Power Plant

• POTENCIA TÉRMICA: 2.109 MWt • POTENCIA ELÉCTRICA BRUTA/NETA: 648 Mwe • MODERADOR Y REFRIGERANTE: Agua pesada (D2O) • COMBUSTIBLE: Uranio natural • GENERADOR DE VAPOR: Cuatro verticales, tubos en "U" Incolloy

800TURBINAUna etapa de alta presión, tres etapas de baja presión . Velocidad:1.500 rpm

• GENERADOR ELÉCTRICO: Cuatro polos. • Tensión: 22 KV, 50 Hz

Laboratory for Testing Materials

PT - TASKS ISO 9001 Certification

• Rolled Joint Strength-Fracture Toughness: Fracture

Lab. Responsible: F. Iorio. • KIH – DHC velocity: Hydrogen Damage and Fracture

Labs. Responsible: G. Domizzi. • Hydride orientation: Hydrogen Damage and

Metallographic Labs. Responsible: G. Domizzi. • Alpha grains and Beta phase thickness:

Metallography and Electron Microscopy Lab. Responsible: P. Bozzano.

• Texture – Dislocation density: X-Ray Diffraction Lab. Responsible: N. Mingolo.

Rolled Joint Strength-Fracture Toughness

FRACTURE AND FATIGUE LAB

12 Profesionals - 6 Technicians

Facilities:

Thermo-mechanical lab.

Mechanical testing labs.

Metallographic lab.

FRACTURE AND FATIGUE LAB.

BACKGROUND

1.-Round Robin Test on Fracture Toughness of PT. (1993, AECL CRNL) Participant Labs.(9)

2.- CANDU Pressure Tubes Surveillance program (CNE).

3.-Fracture Assessment of NDT Indications During GS Repositioning in CNE

FRACTURE AND FATIGUE LAB.

– 1.-Round Robin Test on Fracture Toughness of PT. (1993, AECL CRNL))

Participants Labs.(9)

• (Canada)- AECL-CRNL; AECL-WRNE; HYDRO QUEBEC; ONTARIO HYDRO.

• (Japan)- HITACHI; PNC; KOBE STEEL. • (UK)- AEA-TECH. • (Argentina) CNEA MATERIALS: (3).- Zr-2.5%Nb (CW); Zr-2.5%Nb (HT); Zry-2

FRACTURE AND FATIGUE LAB.

Robin Test on Fracture Toughness of PT. STANDARD:”Standard Test Method for Fracture Toughness

of CANDU PT”

Material: Zr-2.5%Nb HT

FRACTURE AND FATIGUE LAB. Robin Test on Fracture Toughness of PT.

Material: Zr-2.5%Nb CW

FRACTURE AND FATIGUE LAB.

Robin Test on Fracture Toughness of PT.

Material: Zry-2

FRACTURE AND FATIGUE LAB.

POST IRRADIATION STUDIES ON CNE PT at CNEA HOT CELLS

• HWR Surveillance program, set 2 testing

• HWR Surveillance program, IAEA Reference material testing.

• HWR Control rod failure analysis.

• CANDU Pressure Tubes Surveillance program

FRACTURE AND FATIGUE LAB.

2. CANDU Pressure Tubes Surveillance program

TASKS: •Measurement of diameter and thickness. •Tensile properties. •Fracture Toughness.

Hot cells used during the study

Pressure tube sections

Specimens extraction program

█ Position 12 hs

█ Position 3 hs

█ Position 6 hs

█ Position 9 hs

Section of tube after specimens extraction

FRACTURE AND FATIGUE LAB.

Fracture toughness results

0 1 2 3 4 5 6 7 8 9 10 11

0

50

100

150

200

250

300

350

400

A14

L12

other reactors

dJ/d

a (

MP

a)

Fluence ( n/m2 x 10

25)

T=2500C

FRACTURE AND FATIGUE LAB.

3.- .-Fracture Assessment of NDT Indications

During GS Repositioning in CNE

During periodic outages of CNE, Fuel Channel Inspections are performed for GS spacers repositioning and PT/CT gap measurements. Assessment of reportable indications of flaws detected by NDT was carried out from the beginning of such works in 1991.

Hydrogen Damage Labs

Facilites:

•Gaseous Charge (Sievert)

•Chatodic charge

•Tensile strength, weight dead machines (Two)

•Acoustic Emission device

KIH – DHC velocity

IAEA COORDINATED RESEARCH PROGRAMME ON INTERCOMPARISON OF TECHNIQUES FOR PRESSURE TUBE

INSPECTION AND DIAGNOSTICS CRP: I3.30.10 Determination of hydrogen in zirconium alloy components and

Blister characterization by in-situ NDE techniques

Participating labs. Canada, Korea, China. Romania, Argentina

Participation of Argentina:

• hydrogen charge of

•90 samples for hydrogen determination: IGF, HVEMS, DSC, Resistivity, DTA

•17 samples for non destructive techniques

•6 blisters in CANDU pressure tube sections for NDT evaluation

Hydrogen Charge

Background:

Hydrogen concentration: results of IAEA INTERCOMPARISON

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

Me

asu

red

co

nce

ntr

atio

n (

pp

mw

)

gaseous charge concentration (ppmw)

Arg1-2nd (IGF)

Arg2-2nd (IGF)

Korea (IGF)

India (IGF)

Canada (HVEMS)

India (HVEMS)

KIH – DHC velocity DHC Background

• CCT samples fatigue pre-cracked used in CANDU Pressure Tubes Surveillance program

• IAEA COORDINATED RESEARCH PROJECT “Determination crack growth speed during DHC of Zirconium alloys of” CNEA - IAEA Research Agreement Nº 10698/R0. (DCPD)

• Effect of heat treatment on Vp (AE)

IAEA COORDINATED RESEARCH PROJECT

Vp measured by DCPD (CORROSION LAB)

Efect of heat treatment on Vp

1.9 1.92 1.94 1.96 1.98 2 2.02

10-7.9

10-7.7

10-7.5

10-7.3

1000/T(K)

Vp

[m

/s]

380 ºC

430 ºC

500 ºC

Vp measured by AE

Correlation between Vp and cumulative counts:

nondestructive tool for DHC velocity estimation during the

test

0 1 2 3 4 5 6 7

x 10-8

0

1

2

3

4

5

6

7

8x 10

4

Velocity [m/s]

Nc,

Cu

mu

lati

ve

Co

un

t R

ate

.

Hydride distribution, Alpha grains

and Beta phase thickness

Hydrogen Damage, Metallograhy and

Electron Microscopy Labs

•Optical Microscopy •Scanning Electron Microscopy (SEM) •Transmission Electron Microscopy (TEM)

FEI Quanta 200 (HV, LV, ESEM) SyS software for image analisys

Philips CM200 with EDS

Background

• Microstructural characterization of 285 off-cuts of pressure tubes of CNE

•Morpholgy, size and distribution of phases α and β

•Hydride distribution, size and morphology

•Vickers microhardness with 100 grs. Average 235 Hv100

•Morpholgy, size and distribution of carbide precipitates.

• CANDU P Tubes Surveillance program

• Hydride distribution of A-14 and L-12 PT of CNE.

Texture – Dislocation density X-Rays Diffraction Lab

Facilities:

• Philips X-PERT crystallographic texture, Residual stresses and diffraction profiles analysis

• Philips PW 310 difractometer.

Crystallographic texture determination in Zr-

alloys pressure tube materials:

Measurements of direct pole figures (PF) from x-ray

diffraction in different directions of tube: radial (DR),

transverse (DT), axial (DA).

Evaluation of Fd texture factor (Kearns´factor)

calculated from experimental basal (0002) pole figures

for the three principal directions of the tube:

X-Ray Diffraction Laboratory: Background

Pole figures (0002) obtained with Cu-K radiation for differents

sections of Zr-2.5%Nb tube

(a) transverse section , FWHM=0.444o

(b) radial section, FWHM=0.373o

(c) axial section , FWHM=0.399o.

FWHM: full width at half maximum

(a) (b)

(c)

DT//DN DR//DN

DA//DN

X-ray diffraction line profile analysis from

patterns diffraction data and Rietveld refinement

for peak profile:

Analysis of peak broadening (FWHM) caused by the crystalline sizes

and microstrain

X-ray diffraction pattern for the Zr-2.5% Nb tube pressure from transverse

section (DN//DT). FWHM: full width at half maximum

Evaluation of dislocation densities in plastically deformed material from

the peak broadening information.

•According to the CPR, we can participate in the microstructure characterization

of pressure tubes materials.

•Our Laboratory for Testing Materials has IRAM – ISO 9001:2008 and IQNet

certification and AECL qualification for design, development and technical

reports of the following tests:

•Tensile test and fracture strength (K1; J1; R curve) in metallic materials at low

and high temperature.

•Fatigue crack growth in metallic materials.

•Determinations of: Vickers micro hardness, Rockwell B, Rockwell C, Brinell

and Vickers Hardness.

•Hydriding: gaseous charge in metallic materials and cathodic charge in Zr and

Zr alloys

•Determination of crack velocity propagation and measurement of the critical

stress intensity factor (K1H) by delayed hydride cracking in hydride forming

alloys.

•Corrosion tests in autoclave for Hafnium, Zirconium and their alloys.

•Metallography samples preparation and Vickers micro hardness.

•Scanning electron microscopy: obtaining micrographs and measurements in all

type of materials and Qualitative X - Ray energy dispersive spectroscopy.

•X- Ray Diffraction in crystalline materials for texture determination,

dislocations density and phase distribution in crystalline alloys.