a year) but, as discussed previously, this conversion was unique because it did not require major changes to the target dissolution and Mo-99 recovery processes. Conversion of the ANSTO facility began in January 2007 and is still under way.9 Facility commissioning has been delayed because of startup problems with the OPAL reactor. As noted previously, ANSTO was carrying out low-activity Mo-99 production trials but had not yet commenced commercial production when this report was being finalized.

The time required for a Brownfield conversion will depend on the nature of that conversion. If the conversion requires the refurbishment of existing hot cells, it could require as little as 1–2 years once the process development work is completed. Personnel training and regulatory approvals would take an additional 1–2 years. On the other hand, if existing facilities can be adapted to an LEU-based process, the conversion time could be reduced to the time required to modify the process equipment, train staff, and obtain regulatory approvals. This could be as little as a few months to about 2 years once the process development work is completed.


This chapter provides a description and discussion of some general approaches to converting from HEU-based to LEU-based production of Mo-99. The chapter also describes the timing requirements for such conversion. On the basis of this information, the committee finds that:

  • There are two general approaches for converting from HEU-based production to LEU-based production: Brownfield (conversion within an existing processing facility or an unused facility with hot cells) or greenfield (construction of a new processing facility). Brownfield conversion is generally less expensive and takes less time but could interfere with ongoing Mo-99 production operations. Greenfield construction is generally more expensive, but the facility can be custom-designed to meet current and projected Mo-99 production needs, and conversion would not interfere with ongoing Mo-99 production activities.

  • Brownfield conversions can be carried out in as little as a few months to about 2 years once the necessary process development work is completed. Greenfield construction can require 9–13 years from the decision to build to startup of Mo-99 production if a new reactor and processing facility are constructed or about 4–6 years for construction and startup of a new processing facility.


Although physical installation began in 2007, substantial effort had begun prior to this date including planning and preparatory work which was initiated in 2005.

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