RRFM 2009 Transactions - European Nuclear Society

IAEA PUBLICATION: TECDOC-1601 – HOMOGENEOUS AQUEOUS
SOLUTION NUCLEAR REACTORS FOR THE PRODUCTION OF 99 MO
AND OTHER SHORT LIVED RADIOISTOTOPES
E. BRADLEY, P. ADELFANG
Division of Nuclear Fuel Cycle and Waste Technology, International Atomic Energy Agency
Wagramer Strasse 5, A-1400 Vienna – Austria
N. RAMAMOORTHY
Division of Physical and Chemical Sciences, International Atomic Energy Agency
Wagramer Strasse 5, A-1400 Vienna – Austria
ABSTRACT
The concept of a compact homogeneous aqueous reactor fuelled by a uranium salt
solution with off-line separation of radioisotopes of interest from aliquots of irradiated
fuel solution has been cited in a few presentations in the series of International
Conference on Isotopes (ICI) held in Vancouver (2000), Cape Town (2003) and
Brussels (2005) and recently some corporate interest has also been noticeable.
Calculations and some experimental research have shown that the use of aqueous
homogeneous reactors (AHRs) could be an efficient technology for fission
radioisotope production, having some prospective advantages compared with
traditional technology based on the use of solid uranium targets irradiated in research
reactors. A review of AHR status and prospects by a team of experts engaged in the
field of homogeneous reactors and radioisotope producers yielded an objective
evaluation of the technological challenges and other relevant implications. The
meeting to develop the IAEA-TECDOC facilitated the exchange of information on the
‘state of the art’ of the technology related to homogeneous aqueous solution nuclear
reactors, especially in connection with the production of radioisotopes.
This paper presents a summary of the recently issued IAEA-TECDOC and related
IAEA activities since the publication.
1. Introduction
The use of aqueous homogeneous reactors (AHRs), also called solution reactors, for the
production of fission-based medical isotopes is potentially advantageous because of their
relatively lower cost; small critical mass; inherent passive safety; and simplified fuel handling,
processing and purification characteristics. These advantages stem partly from the fluid nature
of the fuel and partly from the homogeneous mixture of the fuel and moderator in that an AHR
combines the attributes of liquid-fuel heterogeneous reactors with those of water-moderated
heterogeneous reactors. If practical methods for handling a radioactive aqueous fuel system are
implemented, the inherent simplicity of this type of reactor should result in considerable
economic gains in the production of fission-based medical isotopes. In June 2007, the IAEA
convened a meeting of 10 technical experts from 7 institutions in 5 countries to review all the
relevant issues and make recommendations for future work. The details of this meeting have
been published in an IAEA TECDOC. This paper presents a summary of that report and IAEA
activities since the publication.
2. Advantages of homogeneous aqueous reactors for the production of fissionbased
medical isotopes
2.1 Reactor design flexibility and inherent nuclear safety characteristics
The flexibility of solution reactor design parameters is an important feature of the AHR concept
that allows customized design configurations to satisfy safety requirements and meet or exceed
isotope-production targets. The greater flexibility afforded by solution reactors with respect to
core operating power range is an important advantage with respect to 99 Mo production demand.
Solution reactors for isotope production could range from 50 to 300 kW.
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