Development of reactor method of radioisotope Actinium-225 production

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Development of reactor method of

radioisotope Ac-225 production

Sergey Nosov, Bekmukhamed Utkelbayev, Yury Aleinikov, Yury Popov, Yury Logachev , Irina Sergeeva

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Objective

Estimation of abilities of small commercial production of radioisotope 225Ас by neutron irradiation of Ra-226 in the Institute of Atomic Energy in Kazakhstan

The Tasks:

1.Study of current IVG-1M reactor opportunities 2.Estimation of mother isotope (Ra-226) availability

3.Determination of need reactor condition to provide actinium production

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Institute of Atomic Energy NNC KZ

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Ac-225

Ас-225 (Т1/2=10 d) for generators of medical isotope

Bi-213 (Т1/2=45,6 m)

Alpha-decay resulting formation of more two

daughter short-living alpha-emitters Fr-221 and At-217

Average energy of alpha-particle 6.9 MeV

Ac-225 is more effective to kill cancer cells than

β-sources, because:

• high linear energy transfer • short track length

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Alpha decay from bone surface

RH Larsen et al., SNM 2002

Institute of Atomic Energy NNC KZ 4

Higher

exposure

image

showing

extensive

overlap of

damage

tracks

near

bone-marrow

interface

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Data of market research

Minimal sales of the Ас-225/Bi-213 generator in USA are equal to 200 millions dollars per year (2006)

Annually in USA and Europe more than 200 000 patients with a cancer of the blood are diagnosed

The current cost of treatment procedure using the radionuclide Bi-213 is evaluated as 30,000 dollars/a patient

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Methods of

Ас

-225 production

Ac-225 production from U-233 radioactive decay (Russia, USA)

Th-229 production by Reactor irradiation of Ra-226

 Accelerator production of Ac-225 using the (p,2n) and (γ,n) reaction

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Institute of Atomic Energy NNC KZ Ra-225 production by Reactor

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Problems

It is required that:

• fluence of fast neutrons with energy of more than 6,42

MeV is not lesser than 8,6·1018 n/(cm2)

• thermal neutrons current density should be decreased in

several hundreds times

• increase of reactor operating time should be provided • radium-226 should be collected

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Spectrum of fast neutrons in IVG.1M to 10 kW

1.0E+06 1.0E+07 1.0E+08 1.0E+09 1.0E+10 1.0E+11 0 2 4 6 8 10 12 14

Energy of neutron Е, МeV

 - empty experimental channel;  - experimental device

N eu tr on f lu x, n /( cm 2 s )

Now value of fast neutrons flux

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Parameters of IVG.1M

parameter title for modernization after upgrade

Heat power, МW ₆₀ ₆₀

The flux of thermal

neutrons, n/sec·cm2 8.81014 11014

The fluence of fast

neutrons, n/cm2 41016 7.21017

Maximum duration of reactor operation at power level , sec 60 МW

6 МW 1 000

14 400 72 0005 000

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Integral spectrum of fast neutron in the experimental channel

(reactor power

Р

= 1 kW

)

1,0E+07 1,0E+08 1,0E+09 1,0E+10 1 2 3 4 5 6 7 8 1 2 ₃ Neutron energy, MeV

1 – empty channel; 2 – shield of UO₂ with water; 3 – shield of UO₂ without water

N eu tr on f lu x, n /s c m 2

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Discussion

Steps promoting production of actinium :

 to upgrade reactor to have possibility for increasing the

fluence up to 7,2·1017 n/сm2

use of enriched (U-235,17%) uranium dioxide and boron

carbide shields in the target during reactor irradiation to have possibility to produce 3·108 Bq of Ac-225 per 1 g of Ra-226

Development of reactor method of radioisotope Actinium-225 production