task #2 produced and characterized pellets until summer 06 ...spes/spes_publ/2_meeting_target... ·...

11

TASK #2TASK #2

ProducedProduced and and characterizedcharacterized pelletspelletsuntiluntil summersummer 06 06 forfor SPES DT projectSPES DT projectSPES: A Mid-term Facility based on a 40 MeV proton Driver and on the Multi-Slices Direct Target concept

Legnaro 19th July - MICHELE TONEZZER

22

Target productionPHILOSOFICAL APPROACH

1) A primary topic in the development of the generation of Radioactive Ion Beams (RIB) is the production of targets characterized by:

high production yield short release times high thermal resistance

2) These capabilities are strongly influenced by many physical and chemical properties of the targets

(e.g. purity degree, grains sizes, grains distributions, grains stoichiometry, porosity etc..)

3) It becomes essential to produce targets with:

a) Strict control of the production method high reproducibility

b) Deep characterization of the samples good knowledge of the produced samples properties


33

Target typologies

1) THE “PARTIALLY” COMPLETE PHASES OF SUITABLE ACTINIDE TARGETS PRODUCTION

Strict control of the production process

In-depth characterization of the physical properties of the produced samples

Handling of the produced samples (reactivity troubles)

CALCULATION CODES

TESTING UNDER BEAM

2) THE COMPLETE PHASES OF SUITABLE ACTINIDE TARGETS PRODUCTION

PELLETS PRODUCTION

PELLETS CHARACTERIZATIONLegnaro 19th July - MICHELE TONEZZER

44

Target typologies

THE MAIN GOAL OF TASK 2 IS THE PRODUCTION OF ACTINIDE TARGETS (UCx, ThCx..)

1) Phase 1 SiC Pellets No Chemical & Radiologic problems

2) Phase 2 LaC2 Pellets Some Chemical problem of UCx (reactivity with oxygen (pyroforic))

SIMILAR CHALLENGES WITHOUT RADIOACTIVITY

3) Phase 3 UCx Pellets Chemical & Radiologic problems (pyroforic and contamination)


55

Phase 1: SiC pellets

1) PELLETS PRODUCTION:

PURCHASED BY THE SAINT GOBAIN(SiC Hexoloy SE)

T= 2000 °CE= 0,7 ± 0,05

Mass before treatment: 800,9 mgMass after treatment: 800,8 mg No weight loss

Emissivity vs. Temperature

0

0.2

0.4

0.6

0.8

1

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Temperature (°C)

Emis

sivi

ty

2) PELLETS CHARACTERIZATION

HIGH TEMPERATURE TESTS

EMISSIVITY TESTS


66

Phase 1: SiC pellets


SEM ANALYSIS

XRD ANALYSIS

3) TESTING UNDER BEAM

(planned at ORNL in the first part of 2007 (January-March) )

3 0 3 5 4 0 4 5 5 0 5 5 6 0 6 5 7 0 7 5 8 00

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

Cou

nts

(a.u

.)

2 th e ta

S iC H e xo lo y S G a s p u rc h a s e d S iC H e xo lo y S G [1 6 0 0 °C , 2 h , A r] H e xa g o n a l 1 9 -1 1 3 1

4) PROBLEMS

NO PROBLEMS UNTIL NOW Legnaro 19th July - MICHELE TONEZZER

77

Phase 2: [LaC2 + C] pellets production

C GRAPHITE

La2O3


A) PRODUCTION OF STARTING PELLETS:

a) PRODUCTION OF OXIDE PELLETS

THE LaC2 PELLETS PRODUCTION CONSISTS IN TWO PHASES: GREEN PELLETS PRODUCTION + THERMAL TREATMENT

b) PRODUCTION OF OXALATE PELLETS:

NOT MECHANICALLY STABLE

BEFORE AFTER

c) PRODUCTION OF OXIDE PELLETS WITH PEHOLIC MICROSPHERES:

MICROSHERES DO NOT PARTECIPATE IN CARBURIZATION PROCESS

AFTERBEFOREMICROSPHERES

88

Thermal treatments

B) THERMAL TREATMENT OF THE STARTING PELLETS

a) CARBURIZATION OF THE STARTING PELLETS

b) SINTERING OF THE CARBURIZED PELLETS

(INFLUENCE THE MECHANICAL PROPERTIES, THE GRAINS SIZES AND THE POROSITY OF THE FINAL PELLETS)

La2O3 + 11C 2LaC2 + 4C + 3CO ↑(Theoretical mass loss: 18.5%)

0 5 10 15 80 900

200400600800

100012001400160018002000

Tem

pera

ture

(°C

)

T ime (h)

CARBURIZATION (C) SINTERING (S)

The furnacesLNL (vacuum, < 1600 °C) TRENTO (Ar, > 2000 °C) LNL (vacuum, > 2000 °C)


99

Phase 2: thermal treatment control

311°C, -6.3 %

479°C, -2.1%

618°C, -1.6%

> 986°C

-H2O

- CO2

Beginning of

Carburization

1) Strict control of the temperature values and temperature ramps (by means of a thermocouple and double frequencies pyrometer);

2) Monitoring of the chamber pressure during the thermal treatment(in order to check the evolution of the reaction product (CO))

3) Monitoring of gaseous species evolved during the thermal treatment by means of a mass spectrometer connected to the furnace vacuum chamber

4) Control of the weight of the pellet during the thermal treatment (in order to have a very accurate control of the occurring reactions)


1010

Phase 2: characterization of pelletsCommonly used techniques

BEFORE thermaltreatment

AFTER thermaltreatment

BLACK GRAIN (CGRAPHITE)

WHITE GRAIN (La2O3)

LOOK SEM pictures EDS analysis

1111

2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 00

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

4 0 0 L a 2O 3/C g ra p h ite a s d e p o s ite d

L a C 2L a 2O 3

L a 2 O 3 /C g ra p h ite g re e n

Cou

nts

(a.u

.)

2 th e ta

Not commonly used techniques: the XRD patterns

1) THE SAMPLE SHOWS THE PRESENCE OF LA2O3 (SEVERAL LANTHANUM OXIDE PEAKS ARE MANIFEST)

2) THE SAMPLE SHOWS ANY PRESENCE OF LAC2 (NO LANTHANUM CARBIDE PEAKS ARE VISIBLE)

3) THE SAMPLE SHOWS THE PRESENCE OF IMPURITIES LIKE BINDER (PRESENCE OF EXTRANEOUS PEAKS)


1212

2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 00

5 01 0 01 5 02 0 02 5 03 0 03 5 04 0 04 5 05 0 0

L a 2O 3/C g ra p h ite 1 2 0 0 ° C ,v a c u u m ,2 4 h L a C 2 L a 2O 3

L a 2 O 3 /C g ra p h ite t r e a te d [1 2 0 0 ° C , v a c u u m , 2 4 h ]C

ount

s (a

.u.)

2 th e ta


2) THE SAMPLE SHOWS YET ANY PRESENCE OF LaC2 (NO LaC2 PEAKS ARE VISIBLE)

1) THE SAMPLE IS YET MADE UP OF La2O3 (HEXANOGAL STRUCTURES)

CRYSTALLINE GRAINS ARE GROWN (La2O3 PEAKS BECOME MORE NARROW AND HIGH)

3) IT IS POSSIBLE TO NOTE THE DECREASE OF THE IMPURITIES QUANTITY (DECREASE OF EXTRANEOUS PEAKS)


1313

2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 00

5 0

1 0 0

1 5 0

2 0 0

2 5 0 L a 2O 3/C g ra p h ite 1 8 0 0 ° C ,v a c u u m ,2 4 h

L a C 2 L a 2O 3

L a 2 O 3 /C g ra p h ite t r e a te d [1 8 0 0 ° C , v a c u u m , 2 4 h ]C

ount

s (a

.u.)

2 th e ta


1) THE SAMPLE SHOWS NOW ANY PRESENCE OF La2O3 (NO La2O3 PEAKS ARE VISIBLE)

2) THE SAMPLE IS MADE UP OF LaC2 (LARGE GRAINS, NARROW AND HIGH PEAKS)

3) THE SAMPLE SHOWS ANY PRESENCE OF IMPURITIES (NO PRESENCE OF EXTRANEOUS PEAKS)


1414

Phase 2: [LaC2 + C] pellets

3) PELLETS TESTING UNDER BEAM

(to be planned)

4) RESULTS

OBTAINED RESULTS

a) COMPLETE CARBURIZED PELLETS HAVE BEEN OBTAINED

b) KNOWLEDGE OF THE CARBURIZATION TEMPERATURE AND DISCRIMINATION BETWEEN CARBURIZATION AND SINTERING PROCESS TEMPERATURE HAS BEEN ACHIEVED

c) VARIOUS SINTERING GRADES OF THE CARBURIZED PELLETS HAVE BEEN OBTAINED

NOT YET OBTAINED IMPORTANT RESULTS

a) MECHANICAL STABILITY OF THE FINAL PELLETS

b) KNOWLEDGE ABOUT HANDLING OF THE FINAL CARBURIZED PELLETS (CHEMICAL REACTIVITY)


1515

Phase 3: UCx pellets


A PELLET OF URANIUM AND THORIUM OXIDE HAS BEEN PRODUCED

ANY THERMAL TREATMENT HAS BEEN YET PERFORMED (not yet available furnace)

3) PELLETS TESTING UNDER BEAM

(to be planned)


NO CHARACTERIZATION ANALYSES ARE DISPOSABLE AT OUR FACILTIES

IT BECOMES NECESSARY TO RELY ON DEDICATED REASEARCH CENTRES

( IT IS PLANNED FOR TOMORROW A VISIT AT I.T.U. OF KARLSRUHE)


1616

TASK #2TASK #2

ProducedProduced and and characterizedcharacterized pelletspelletsuntiluntil summersummer 06 06 forfor SPES DT projectSPES DT projectSPES: A Mid-term Facility based on a 40 MeV proton Driver and on the Multi-Slices Direct Target concept


task #2 produced and characterized pellets until summer 06 ...spes/spes_publ/2_meeting_target... ·...

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