Status of SFR Metal Fuel Development

2013. 3. 5

Chan Bock Lee, Byoung Oon Lee, Ki Hwan Kim and Sung Ho Kim

International Conference on Fast Reactors and Related Fuel Cycles : Safe Technologies and Sustainable Scenarios (FR13)

March 4-7, 2013, Paris, France

2

Content

Introduction

Status of SFR Metal Fuel Development

• Fuel fabrication

• Cladding development

• Fuel performance evaluation

Conclusion

3

Introduction

Metal Fuel Recycling in Sodium-cooled Fast Reactor

• Enhanced utilization of uranium resource

• Efficient transmutation of minor actinides

• Inherent passive reactor safety

• Proliferation resistance with pyro-electrochemical fuel recycling

To meet the goals of Generation IV SFR

- Sustainability, Safety, Economy and Proliferation Resistance

4

PWR-SFR Closed Fuel Cycle

Utilization of uranium resource can be enhanced by 100 times

Space for high level waste can be reduced by 1/100

Duration needed for radio toxicity decrease can be reduced by 1/1,000

High proliferation resistance by handling TRU together

Spent Fuels

High

Level

WasteDisposalDisposal

Sodium-

cooled

Fast

Reactor

U-TRU-Zr FuelU-TRU-Zr Fuel

Interim Interim

StorageStorage

PWR

* TRU (Transuranics) : Pu + MA

* MA (Minor Actinides) : Np, Am, Cm

Pyroprocessing

5

Gen-IV Target Rational

Peak Burnup (at.%) ≥20 High burnup

Peak Cladding Damage(dpa) ≥ 200 High burnup

Peak Cladding Temperature (oC) ≥ 650 High thermal efficiency

Remote fabrication of metal fuel with radioactive minor actinides

•Control of Am vaporization during metal fuel casting

•Reliable remote fuel fabrication

Advanced cladding for high burnup and high temperature

•High strength FMS(ferritic martensitic steel), ODS(oxide dispersion steel)

Verification of Irradiation performance of U-TRU-RE-Zr metal fuel

•Effect of minor actinides and rare earths(RE) in fuel

•High burnup performance

Fuel Performance Targets

Technical Challenges

SFR metal fuel targets and technical challenges

6

Fuel Slug Fabrication

Fuel slug gravity casting system

- Advanced fuel casting system to control

evaporation of volatile americium during

melting of U-TRU-RE-Zr fuel alloy with

minor actinides

- The melt was poured downward into a

graphite distributer where the quartz mold

assembly were attached.

Chamber

Mold

Coil

Control Panel

Vacuum Pump

Pressurizer

Chamber

Mold

Coil

Control Panel

Vacuum Pump

Pressurizer

Casting process investigation - Casting conditions

• batch size, casting temp.,

casting pressure, heating rate, etc

- Casting components

• Crucible, distributer, mold

- Coating materials and method in crucible

• Y2O3, TiC, ZrC, HfC, etc

• Plasma, slurry coating

Test rods of coating materials

melt dipping test of plasma coated Y2O3 in U-Zr melt

7

Characterization of fuel slugs - Alloying composition

- Density

- Microstrucure

- Thermal properties

- Mechanical properties

Fuel slugs by gravity-casting - Varying fuel composition

U-(5,10,15)Zr, U-10Zr-(2,4,6)RE,

U-10Zr-5Mn, U-10Zr-RE-Mn

- Dimensions: (5.0~10mm) Φ x 300mmL

- Retention of volatile surrogate Mn

• ~94% at 1 bar(Ar) casting pressure

- Radiography : gamma and neutron

Fuel slugs

Gamma radiography

(U,Si)Zr2

Zr ppt

U-10Zr

Ce ppt

10Zr

100 200 300 400 500 600

0

10

20

30

40

50

60

U-15Zr

U-10Zr

Th

erm

al C

on

du

ctivity (

w/m

-K)

Temperature (oC)

0 200 400 600 800 1000

0.0

0.5

1.0

1.5

2.0

2.5

L

/L (

%)

Temperature (oC)

U-15Zr (KAERI)

U-10Zr (KAERI)

U-10Zr (Ref.)

U-10Zr (Ref.)

U-5Zr (KAERI)

Microstrucure of U-10Zr and U-10Zr-Ce fuel slugs

Thermal conductivity Thermal expansion coefficient

Fuel Slug Fabrication

8

Injection Casting

Injection casting of fuel slug

- Vacuum injection casting of U-Zr and U-Pu-Zr is a proven technology with vast

experience in US

- The method to control evaporation of volatile elements during casting needs to be

developed

Establishment of small versatile injection casting equipment

-Capacity : 1 kg/batch max. U alloy

- Fabrication tests of surrogate(Cu) fuel slug

Cu Slug

9

Advantages -Casting Mold not needed

-Process loss reduction

-Fuel without Na bond(potential)

Future work -Consolidation of fuel particles

-Characterization and irradiation test

Particulate Fuel

Particulate fuel concept - Fuel particle fabrication followed by vibro-

compaction or consolidation of fuel

particles

Fabrication of atomized powder - U-10wt%Zr fuel particles were fabricated

by atomization process

- Particle size : avg. 60mm and 300mm

U-10wt% Zr powder U-Zr compaction Centrifugal atomization

10

Remote Fuel Fabrication

Remote fabrication in Hot Cell - Accessibility, manipulation, maintenance and viewing

- Reliability and practicality

- Experience : DUPIC(: Direct Use of spent PWR fuel In CANDU reactors) fuel

rod fabrication in hot cell

Preliminary conceptual design of TRU fuel fabrication facility - Establishment of design criteria

- Fuel fabrication equipments and facility

DUPIC fuel rod fabrication Operation simulation

11

Objective − Development of high strength FMS(HT9M) cladding for high burn-up and

high temperature application

Creep rupture strength (650oC) improved by more than 35 % from HT9

Cladding material Development

+ Mo + W

+ W

Solid Solution

Strengthening

Solid Solution

Strengthening

+ V + Nb

+ V + NbC, N, B Ta

Precipitation

Strengthening

Precipitation

Strengthening

Strengthening mechanisms of FMSStrengthening mechanisms of FMS

Alloy design for advanced cladding

100 1000100

650 oC

Str

ess (

MP

a)

Time to Rupture (hr)

HT9

T92

PNC-FMS

KAERI Batch 1

Creep test (650 oC)

12

Cladding Tube Fabrication

Hot extrusion

Heat treatment

Cladding tube

Drawing

Intermediate cladding

1 ton ingot

Objective - Development of cladding tube fabrication

process

Status - Fabrication of cladding tube

• Fabrication of mother tube

Melting (1 ton ingot)

Fabrication of Hollow billet

Hot extrusion and pilgering

• Fabrication of cladding tube(HT9, Gr.92)

Drawing and intermediate heat treatment

Final heat treatment (1050oC, 760oC)

Final dimension of cladding tube

(OD 7.4mm, T 0.56mm, L 3,000mm)

Future work - Fabrication of cladding tube(HT9, HT9M)

with optimized process

13

Evaluation of cladding tube

Objective

- Production of performance data

Status

- Setting of cladding test equipment

• Tube creep/burst test machine

• Cladding/sodium compatibility facility

- Evaluation of cladding tube

• Tensile test (R.T. ~ 700oC)

• Burst test (R.T. ~ 658oC)

• Creep test (650oC)

Future work

- Fast neutron irradiation tests

• creep, swelling, tensile, fracture

toughness, microstructure, etc.

0 100 200 300 400 500 600 700 800

100

200

300

400

500

600

700

800

900

Str

ess (

MP

a)

Temperature (oC)

KAERI Ref

YS

UTS

10 100 1000 10000

60

80

100

120

140

160

180

200

220

240

Ho

op

str

ess (

MP

a)

Rupture time (hr)

HT9 (KAERI)1)

HT9 (KAERI-Round bar)2)

HT9 (EP0287710A2)3)

HT9 (EP0287710A2)4)

HT9 (EP0287710A2)5)

Creep rupture strength

Ultimate Hoop stress

Tensile properties

Ref.) W.L. Bell, et al., GE, Proc. of Topical Conf.

on Ferritic Alloys for use in Nucl. Energy Technologies (1983)

1) 1038C, 5min → 760C, 30min

2) 1050C, 30min → 750C, 2hr

3) 1100C, 5min → 760C, 30min

4) 1040C, 5min → 650C, 2hr

5) 1040C, 5min → 704C, 2hr

Tensile tester

Burst tester

Creep tester

14

Study on Barrier between Fuel and Cladding

Barrier to prevent interaction between fuel and cladding - Eutectic melting at high temperature

- Degradation of cladding by rare earth fission products

Investigation of barriers - Effective barrier material : Cr, V, Cr2O3 ..

- Barrier fabrication methods : electroplating, oxidation, nitrification, metal liner..

- Barrier on fuel slug : Surface oxidation of metal fuel slug

Fe

Ce

La Cr

Zr

Fe

Cr

Ce

La

V

V

Vanadium (660oC/25 hr)

Cr Electroplating (800oC/25 hr)

Zirconium (660oC/25 hr)

U -

FMS Cr2O3 U-10Zr

Cr2O3

(800oC/25 hr)

15

Irradiation Test of Metal Fuel in HANARO

Objectives

- Evaluation of metal fuel fabrication and design

parameters

- Evaluation of the effect of impurities to define the

allowable levels

- Evaluation of barrier performance

Status

- Irradiation capsule design and fabrication

• 12 test fuel rods : U-10Zr and U-10Zr-5Ce

• Electroplated Cr barrier (20μm)

• Irradiation up to 3 at.% burnup (‘10.11~‘12.1)

- Post-irradiation examination

• γ- scanning

• Fission gas release measurement

• Fuel rod cutting and destructive tests

Future Work

- Transient simulation tests in hot cell

Lower fuel rodlet

Upper fuel rodlet

Coolant

Fuel slug

Hf tube

A-AB-B Neutral plane of core

Bottom view

HANARO irradiation Test Capsule

Fuel

Cr barrier

Clad

0

5

10

15

20

25

30

0.000

5.000

10.000

15.000

20.000

25.000

30.000

0 20 40 60 80 100 120 140 160 180 200

upper part Linear (kW/m)

lowe part Linear (kW/m)

upper part burnup(GWD/MTU)

lower part burnup(GWD/MTU)

Linear Flu

x(kW/m

)

Total Operation Day

Bu

rnu

p(G

WD

/MTU

)

Linear Flu

x(kW/m

)

Total Operation Day

Test fuel rods Irradiation history

Before irradiation After irradiation Cr barrier after irradiation

16

Metal fuel rod performance analysis code

PUMA - Performance of Uranium Metal fuel rod Analysis

code

• Applicable only to metal fuel

• Mechanistic models are employed

Code structure - 1D FE-based thermal & mechanical modules

• Thermal analysis is followed by mechanical

analysis

- Coupling between thermal and mechanical

analyses

- Models such as fission gas release and the fuel

element redistribution were incorporated

Code verification and validation - Comparison of code prediction with fuel

performance test data and prediction of other

code is underway.

Thermal

analysisConstituent

redistribution

Mechanical

analysis

Plenum

pressure

Coupling

Fission gas

release

Load at

time step

Iteration scheme

Fission Gas Release

Verification of thermal analysis

Fuel constituent redistribution analysis

0 2 4 6 8 10 12 14 16 18 20

0

10

20

30

40

50

60

70

80

90

U-10Zr

U-8Pu-10Zr

U-19Pu-10Zr

GRISIS

METAPHIX-1

Russian U-Zr

Fra

ctio

na

l g

as r

ele

ase

, %

Atomic % burnup (peak)

17

SFR-Fuel-Pyroprocessing Milestone

Korea-US Joint Fuel Cycle Study

(Pyro-electrochemical Recycling)

’16 ’20 ’25 ’28’12 ’23 ’30

U-Zr Fuel Fabrication Tech. UFMF D/C.

SFR (150 MWe) Operation

LTA

(’34)

Startup Test

UFMF(’24)

TFRF D/C

TFRF(’25)

C/P(’22) O/P(’28)

KAPF(’25)

KAPF: Korea Advanced Pyroprocess Facility

UFMF: U-Zr Fuel Manufacturing Facility

TFRF: TRU Fuel manufacturingResearch Facility

LTA: Lead Test AssemblySTELLA: Sodium integral effect TEst

Loop for safety simuLation and Assessment

STELLA-2(’16)

U-Zr Fuel

’11 ’21

LTR

(’30)Remote Fuel Fabrication Tech.

1 Phase

(’11-’12)

2 Phase

(’13-’16)

3 Phase

(’17-’20)

Specific Design

Approval(’20)

Batch

(’39)TRU Fuel

’27’24

FSAR(’26)

’39’34

PRIDE Operation

KAPF D/C

DFDF/ACPF Operation

TRU

Specific

Design

(’17)

PSAR(’20)

SFR Specific Design

STELLA-1(’12)

18

Conclusion

Metal fuel recycling in SFR

- Enhanced utilization of uranium resource

- Efficient transmutation of minor actinides

- Inherent passive reactor safety

- Proliferation resistance with pyro-electrochemical fuel recycling

Demonstration of technical feasibility of recycling TRU metal fuel

by 2020

- Remote fuel fabrication

- Irradiation performance up to high burnup

19

Thank You

감사합니다

20

Nuclear Power Plants in Rep. of Korea

Wolsong (#1,2,3,4)

Shin-Wolsong (#1,2)

Ulchin (#1,2,3,4,5,6)

Shin-Ulchin (#1,2)

Kori (#1,2,3,4)

Shin-Kori (#1)

Shin-Kori (#2,3,4)Yonggwang

(#1,2,3,4,5,6)

Units [MWe]

Site

(Sin)Kori

(Sin)Wolsong

Yonggwang

Ulchin

Total

In Operation

5 (4,137)

4 (2,779)

6 (5,900)

6 (5,900)

21 (18,716)

UnderConstruction

3 (3,800)

2 (2,000)

-

2 (2,800)

7 (8,600)

Total(2016)

8 (7,937)

6 (4,779)

6 (5,900)

8 (8,700)

28 (27,316)

Radioactive Waste

Disposal Facility

(Under construction)

Hydro

0.5%Etc. 1.3%

Fossil

Fuel

66.9%

※ Ref: www.kosis.kr(2010)

Plants Under Construction

− OPR1000 : Shin-Kori (#2), Shin-Wolsung (#1,2)

− APR1400 : Shin-Kori (#3,4), Shin-Ulchin (#1,2)

21

Perf. Eval. Duct Fab.

Performance Evaluation

SFR Metal Fuel Development Plan ’16 ’20 ’25 ’28 ’11 ’18 ’24

KAPF

TRU Fuel Fab. Facility

U-Zr Fuel Fab.

Facility

U-Zr Metallic Fuel Fabrication Tech. Dev.

Fuel Slug (U-Zr)

Fuel Rod (U-Zr)

U-Zr Fuel

Batch Loading

KAPF: Korea Advanced Pyroprocess Facility

UFMF: U-Zr Fuel Manufacturing Facility

TFMF: TRU Fuel Manufacturing Facility

LTR: Lead Test Rod

LTA: Lead Test Assembly

Supply of U-Zr fuel as starting fuel of prototype SFR Transition to TRU fuel through demonstration of TRU LTA fuel

Non-fuel Bearing Assembly

•Experimental SFR(Russia, CEFR, Joyo, FBTR) •Prototype SFR(BN-800, ASTRID, Monju, PFBR) •Fuel rod, rod bundle and fuel components will be irradiated.

U-Zr Slug HANARO Irradiation

UFMF (3 t-HM/yr)

Cladding Fabrication

Prototype Cladding

Cladding/U-Zr Fuel Irradiation

Prototype Duct

TFMF (1.5 t-HM/yr)

’30

ATR Irradiation

’34 ’27

LTR

297 kg-TRU/y (20FA/y)

Remote Fuel Fab. Tech. Development TRU Fuel Fab.

Joint Fuel Cycle Study of Korea and US

’39

Fuel Assembly (U-Zr)

Prototype SFR(150 MWe)

LTA

TRU Rod Fab. and Irradiation

2 kg- TRU/y

•Experimental SFR(Russia, CEFR, Joyo, FBTR) •Prototype SFR(BN-800, ASTRID, Monju, PFBR)

22

SFR Metal Fuel

○ Fuel material: U-Zr & U-TRU-Zr ○ Cladding & duct material: Ferritic/martensitic steel ○ Active fuel length: 900 mm ○ Cladding diameter & thickness: 7.4 mm & 0.6 mm ○ Fuel rod length: 3,700 mm ○ Overall assembly length: 4,600 mm

23

Zr

Pyroprocessing

Fuel Ingot

(U+TRU+RE+others)

Fuel

composition

(U-TRU-Zr)

Fuel Slug

Casting

Fuel Rod (Na insertion,

End cap welding) Fuel Assembly

Cladding

Fuel

Assembly

Components

SFR

Scrap Recycling

Metal Fuel Fabrication Process

24

Continuous casting has advantages

in preventing the evaporation of

volatile Am because inert over

pressures can be easily applied

Waste can be reduced due to no

use of casting molds(ex. quartz), and

product yields can be increased due

to little heel left in the crucible after

casting

Preliminary surrogate fuel(Cu) slugs

were cast under inert atmospheric

pressure of 760 torr. The surrogate

fuel slug had diameter of about 7

mm and length of about 2.3m.

Continuous Casting

'

25

Schematic Flow of Cladding Tube Fabrication

Melting

(Ingot)

Forging Machining

(Hollow billet)

Hot-extruding

Drawing

Sub-critical

annealing

Intermediate

annealing

Pilgering

Intermediate

annealing

Drawing

Intermediate

annealing Normalizing

& Tempering

Cladding tubes

Reduction

26

Process Development

TRU MetalFuel Fabrication

Declading/Voloxidation

Hull

LLW

Off-gasTreatment

Sodium CooledFast Reactor

FP gases

(U+TRU+FP)Metal

TRU : Transuranic elements

NM : Noble metal elements

FP : Fission products

Air

UO2+(TRU+FP)Oxide(Granule)

Oxide ReductionElectrorefining

Electrowinning

PWRSF

Reuse/Storage

Uranium Recovery

Used Salt(U+TRU+FP)

Salt Treatment

Salt Recycle/Immobilization

Clean Salt

Clean Salt