materials characterization for generation iv reactors · o pie of structural materials after...

Materials Characterization for Generation IV Reactors

Natalia Luzginova

4th Nordic Seminar on Generation IV Nuclear Reactors

Risø, Denmark

29-31 October 2012

Outline

Introduction

Materials Characterization projects

ARCHER

o Post Irradiation Examination (PIE) of HTR graphite

grades

o Characterization of alloy 800H

GETMAT

o PIE of structural materials after irradiation in Lead

Bismuth Eutectic (LBE)

o Assessment of alternative joining techniques for

advanced materials

MATTER

o Fracture toughness testing in LBE

o Negligible creep domain definition

NRG provides consultancy services and products based on nuclear technology

Over 350 employees

First-rate nuclear R&D infrastructure, including a High Flux Reactor and Hot Cell Laboratories

Focus on three key areas:

R&D and support for existing reactors; and innovative systems including

fusion and fission reactors

Radiation protection and waste management services

Radioisotopes for medicine and industry

Introduction

Introduction

Actinide Laboratory Radiological Laboratory

Hot Cell Laboratory High Flux Reactor

Outline

Introduction


ARCHER


grades


GETMAT




advanced materials

MATTER



PIE of HTR graphite grades

Graphite is used as a neutron moderator and reflector material

(AGR, Magnox, RBMK, MTR, HTR)

For HTR design a database containing behavior of different

graphite grades under irradiation at temperatures relevant for

HTRs is being created

Main aim is to investigate changes of HTR graphite properties

due to neutron irradiation between 650 and 950 °C

M.C.R. Heijna, J.A. Vreeling

INGSM-13 (2012)


INNOGRAPH experiments

Four irradiation experiments

~ 600 irradiated graphite

samples

Graphite grades from Toyo

Tanso, SGL Carbon and

GrafTech International

included

o Pet and pitch coke

grades included

o Extruded, iso-moulded

and vibro-moulded

grades included


INGSM-13 (2012)

Low dose Medium dose High dose


Experiment is designed to allow loading and assembling in

hot cell

Each experiment contains 24 thermocouples and 9

dosimeter sets

~ 180 samples per experiment


Measured materials properties

Volume and length change

Young’s modulus

Thermal expansion and diffusivity

Microscopy

Strength properties

XRD and XRT


INGSM-13 (2012)


M.C.R. Heijna, J.A. Vreeling, INGSM-13 (2012)

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0

-10

-5

0

5

10

15

20

25

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0

-10

-5

0

5

10

15

20

25

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0

-10

-5

0

5

10

15

20

25

0.0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 22.5 25.0

-10

-5

0

5

10

15

20

25

650°C

750°C

850°C

950°C

V

/V0 (

%)

650°C

750°C

850°C

950°C

650°C

750°C

850°C

950°C

V

/V0 (

%)

dpa

650°C

750°C

850°C

950°C

dpa

Extrusion Extrusion

Iso-moulding Vibro-moulding


Conclusions

4 irradiation experiments are successfully completed

providing HTR relevant data (well beyond of “turn around”)

It is shown that the rate of material property changes is

(strongly) temperature dependent

New irradiation experiment coming up to cover missing

information at low dose

Low dose Medium dose High doseM.C.R. Heijna, J.A. Vreeling, INGSM-13 (2012)

Outline

Introduction


ARCHER


grades


GETMAT




advanced materials

MATTER



Alternative joining techniques

Ferritic-martensitic (FM) steels (9-12 wt.% Cr) and Oxide

Dispersion Strengthened (ODS) FM steels are promising

candidate materials for Gen4 fission and fusion reactors

Conventional welding of these steels without destroying

the characteristic microstructure is a challenge

In this research, feasibility of

pioneering non-fusion

welding techniques such as

Friction Stir Welding (FSW) is

performed to join these

advanced steels

P. Yvon et al, 2009

Friction Stir Welding

TWI’s high precision FSW machine

located in South Yorkshire, UK. P91 steel plates (300 x 90 x 6.5 mm)

Fixtures (a) (c)

P 91 plate

P 91 plate Friction Stir Weld

(b)

M. Kolluri, N.V. Luzginova, E. W. Schuring, W. Kyffin, J. Martin, 9th ISFSW (2012)

Friction Stir Welding (FSW)

Tool material selection

Preliminary trials are performed with two front running tool materials

Tool design suitable for each material was selected based on prior

successful experience on austenitic stainless steels

W-Re tool material:

W-25% Re tool

W-Re/cBN tool material:

60-70% c-BN in a W-25% Re matrix tool

M. Kolluri, N.V. Luzginova, E. W. Schuring, W. Kyffin, J. Martin, 9th ISFSW (2012)

Friction Stir Welding (FSW)

Measured materials properties

Tensile and notched tensile tests

Impact properties

Fracture toughness

Hardness

Microscopy

Strength properties

M. Kolluri, T. Bakker, H. Nolles, P. ten Pierick, N.V. Luzginova, E. W. Schuring, J. Martin, NuMat 2012

FSW: tensile properties


FSW: impact properties


FSW: microscopy

FSW: hardness


FSW: conclusions

FS welded specimens has shown superior tensile strength properties

than the base material and a considerable reduction in the ductility.

Application of PWHT helps to partially recover the ductility

A substantial increase in DBTT was observed due to FSW. Application of

PWHT reduces hardness of the weldment and recovers the impact

properties

Several recrystallized regions of soft ferrite was observed in the cap and

root regions of TMAZ of the weld after PWHT.

Proper control of gain refinement in the TMAZ during FSW, in order to

avoid PWHT, is key for the application this method for joining of the

selected steels for nuclear applications


Outline

Introduction


ARCHER


grades


GETMAT




advanced materials

MATTER



Fracture toughness testing in LBE

Liquid metal embrittlement (LME)

“Reduction of ductility and fracture

toughness of metals when simultaneously

subjected to stresses and wetting by liquid

metals” E. Glickman, 2000

LME can be influenced by a large

number of testing parameters

There is a large scatter during testing

in liquid metal

Main goals:

Development of the guidelines for

fracture toughness (FT) testing in LBE

Evaluations and verifications of FT in

LBE

LFR pilot plant (MYRRHA)


A new test set-up has been developed by NRG for fracture

toughness tests in LBE

3-tank system set-up

Set-up is designed to fit into the

hot cell

Instron 1343 hydraulic testing

frame with a 25 kN load cell

M. Jong, D.A. Boomstra, H.S. Nolles, G. van der Meij, N.V. Luzginova, MUNECO 2012


The crack propagation will be

calculated from the load line

displacement measured by

means of two displacement

transducers

Measurement method is

evaluated at 250 oC in air (with

DCPD, LVDT and multi

specimen method)

Current specimens size is ½T

C(T) specimens

Adaptable to tensile and 1T

C(T) specimens



Active oxygen control system (produced by KIT)

Preconditioning of LBE in the storage tank, final conditioning in the test

tank

2 oxygen sensors in test tank and 1 oxygen sensor in the storage tank

O2 sensors



Conclusions

FTT set-up including oxygen control system is installed

and commissioned

Fracture Toughness Test Set-up Oxygen control system


Thank you for your attention

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