Theoretical assessment of specific radioactivity the effect of target burn up, isotope dilution and target purity and the application for lu 177 production

-The reactor-based radioisotope production advantage lies in its large production capacity, comfortable targetry and robustness.. - SA assessment becomes a lot more serious than reaction

Conference Presentation

4th Asia-Pacific Symposium on Radiochemistry ’09November 29 – December 4, 2009 Napa Valley, California, U.S.A.

-The reactor-based radioisotope production advantage lies in its

large production capacity, comfortable targetry and robustness

However, the specific activity is a subject to be concerned.

- SA assessment becomes a lot more serious than reaction yield

which is a conventional concern for radioisotope producers.

- Neuron capture reactions

- Reaction yield assessment vs Cross section & Neutron flux

Present issues and requirements:

-Very high specific radioactivity radioisotope & reasonable reaction yield

Problem

Specific radioactivity

Neutron parameters &

characteristics

elemental impurities

Activation and post-irradiation time

Yield build-up Target burn-up

Unwanted nuclear reactions

for optimization and quality assurance purposes.

- SA assessment approaches formulated in mathematical equations

to get the highest standardization

Three main nuclear reactions for reactor based radioisotope production

For lower

SA isotope production

Simple Target System: For lower SA radioisotope production

S t S

. − ∆

=

Un-burned atom numbers of S

Burned-up atom numbers of Sg,A

A g A

, 0 ,

, ,

,

irr A g A

g A

g

t S

/ 693 0

2 /

Reaction yield of Sg,Afor Ri

) (

.

.

,

1

, 1

,

i R irr

A S

A i

S R

i th S

Ω

, 1

,

1 1 , ,

max

h p

S R

i th

S o

N

A i

∆

− Λ

Ω

Specific Radioactivity (SA) in Simple Target System

)

.

, 2 ,

2

, 1 ,

1

irr A g A

g

irr A S A

irr A S A i

i irr

i

t S

t S

t S

R R

t

irr A S irr

A S A

i

j m

m m R i c

irr i R irr

A S

j m

m m R i c

irr i R irr

A S

c

i

t t

i th S

R

t t

t

t t

t

t

R

e P P b e

e e

e

e e

e SA

1

2

,

1

.

.

.

.

,

, 2 ,

1 ,

1

1 ,.

, 1

1 ,.

, 1

).

/ (

).

/ ) ((

−

∆

−

+ Ω

∆

− Λ +

) 1

(

100 ( 1 , ). . ( 1 , ). .,

irr A S i R irr

A S i R irr

i

t t

=

irr

t R

dt

SA d

irr i

0 ) ).

/ (

.

.

).(

(

) ).

/ (

).(

.

(

max , , 2 ,

2

max , , 1 ,

1

max , max

, max

,

,

1

max , , 2

max , , 1

max ,

max , max

, , 1

,

1

1

2

.

.

1

2

.

.

−

−

−

− Λ

− Λ

− Λ

−

∆

−

SA irr A S A

SA irr A S A

SA irr i R i

SA irr i R SA

irr

A

S

SA irr A S SA

irr A S SA

irr i R SA

irr i R i

SA irr A S

A

t S

t S

t R

t t

t t

t t

R

t S

e P P b e

a e

e e

e P P b e

a e

e e

If the differential of SARi

No maximum SA

SA of 177 Lu in 176/ 175 Lu target ( A typical 2- isotope target system)

SA of 177 Lu in 176/ 175 Lu target ( A typical 2- isotope target system)

100% 176 Lu

74% 176 Lu +

74% 176 Lu + 26% 175 Lu

t Y t SA

26% 175 Lu

Complex Target System: For higher SA radioisotope production

c j m

m m R i irr

irr irr

B c

t

t t

d t

d t

d S

d d d d

e d

d d d

e d

d d d

e f

f N

N

.

3 2 3 1

.

2 3 2 1

.

1 3 1 2

.

3 2 ,

0

1 ,3

2 1

, 1

) )(

( ) )(

( ) )(

(

.[

.

−

∆ Λ

− Λ

−

∆ Λ

−

∆ +

∆

− Λ

×

∆ Λ

∆

− Λ

Ω

=

→

− Λ

, 2 ,

2 ,

2 ,

2 ,

,

2 ,

2 , ,

2 , ,

, 2 ,

2

, 2 ,

.

.

.

, 2 ,

,

).

.(

).

.

(

).

.

( )

(

) (

.

c A g y R irr

y R irr

B S B

y

irr B S B

y y

A g y

irr y R B

y B

A g y B

A g y y

A g y

B y

B y

B c

A g

t t

t S

R

t S

R R

S R

t S

R S

S R S

S R R

S R

S R S

R

y th

S o t

S

e e

e e

e

N N

λλ

λ λ

λ

φ

) (

) ) (

/(

) (

, 1

, ,

k

Ri k

n j

j

Ri j Ri

j

n j

j

Ri j Ri

) / (

).

/ ) ((

,

1

.

.

.

,

, 1 ,

1

1 ,.

, 1

1 ,.

, 1

P P

b e

e e

e

e e

e SA

A imp

t i

th S

R

t t

t

t t

t t

R

irr A S A

i

j m

m m R i c

irr i R irr

A S

j m

m m R i c

irr i R irr

A S

c i

+ Ω

∆

− Λ +

SA of 177 Lu in 176/ 175 Yb target ( A typical multi- isotope target system)

Nuclear characteristics of radionuclides produced in 176 Yb target matrix [3]

( * Elemental Lu content being of natural isotopic abundance in 176 Yb target is assumed as 97.41 % 175 Lu and 2.59 % 176 Lu)

SA of 177 Lu in 176/ 175 Yb target ( A typical multi- isotope target system)

SA of 177 Lu radioisotope in the 176 Yb target vs.

irradiation time and content of 174 Yb- and elemental Lu- impurities.

A : SA of 177 Lu isotope in impurity-free 176 Yb target

B : SA of 177 Lu isotope in the 176 Yb target containing 1.93% 174 Yb

C : SA of 177 Lu isotope in the 176 Yb target containing 50 p.p.m Lu impurities.

D : SA of 177 Lu isotope in the 176 Yb target containing 1.93% 174 Yb and 50 p.p.m Lu impurity.

150

A : SA of 177 Lu isotope in the impurity-free 176 Yb target

B : SA of 177 Lu isotope in the 176 Yb target containing 1.93% 174 Yb

C : SA of 177 Lu isotope in the 176 Yb target containing 50 p.p.m Lu impurities.

D : SA of 177 Lu isotope in the target containing 1.93% 174 Yb and 50 p.p.m Lu impurity.

(*) is the experimental measurement result for this type of target.

SA assessment methods have been established and

equations formulated for SA calculation of different target

SA assessment is an effective tool for optimization and

quality assurance in the radioisotope production

Radioisotope Development Facilities

• Nuclear Reactor at Lucas Heights

– HIFAR (10MW) in operation since 1958

– OPAL (20 MW) inauguration in 2008

• Low Enriched Uranium (LEU)

• National Medical Cyclotron (NMC)

– Based at Camperdown

– Based at Camperdown

– Commissioned in 1992

– 30 MeV from IBA

– Versatile: Production & Research

• Further investment in Automation

• Full GMP Facilities

New OPAL reactor core

Large Volume Irradiation Facilities

Storage Rack

for Irradiation

for Irradiation Facilities

Irradiation RIGs

Bulk Irradiation Facilities

Pneumatic

Transfer

System Tubes

Hot Labs

176Lu /176Yb target irradiation can

Automated separation of 177Lu from 176Yb target