NUCLEAR MEDICINE | Co60 Although cobalt-60 supply continues to increase, in
recent years this growth has been out-paced by growth in demand. This is of concern to the healthcare sector that relies on irradiation sterilisation to enable it to meet growing patient treatment needs. Whilst alternatives to cobalt-60 technology are available for sterilisation, these alternatives do not have the capacity to meet existing demand or the infrastructure to enable rapid growth to meet future demand. At a time of increasing sterilisation demand, there
have been a few disruptions to cobalt-60 production. This includes the temporary shutdown for refurbishment of some existing cobalt-60 production reactors in Canada and Argentina, and periods of reduced supply from Russia. Reactor refurbishment is critical to extending the life of reactors by 25-30 years and but also creates opportunities to increase cobalt-60 production for the long term.
Reactor refurbishment and conversion for cobalt-60 production In the case of the ongoing Bruce Power Life Extension Program and Major Component Replacement Project, the opportunity has been taken to add more cobalt-59 adjusters to increase cobalt-60 production above the existing levels. This investment will secure the operation of these reactors and cobalt-60 production until 2064. At the OPG Darlington refurbishment, the opportunity
will also be taken to convert these four reactors to enable cobalt-60 production. This will add valuable cobalt-60 supply and builds on OPG’s experience of cobalt-60 production at Pickering. The Pickering reactors have been scheduled to cease
commercial operation at the end of 2024, however, the Ontario Government recently confirmed its support of OPG’s plan to refurbish the Pickering B reactors that are also cobalt-60 producing units. This refurbishment is subject
to approval by the Canadian Nuclear Safety Commission (CNSC) that is already considering a request from OPG to extend the operating licence of the Pickering B reactors until 2026. If approved, the reactors will continue operation until shut down to begin the refurbishment programme. Refurbishment would enable continued operation of these reactors for a further 30 years. The CANDU reactor at Embalse, Argentina, has also been
refurbished recently to enable continued operation and cobalt-60 production for a further 30 years. Additionally, Russian cobalt-60 production has been expanded. While two of the cobalt-60 producing units at the Leningrad Nuclear Power Plant have been shut down, five reactors at Kursk and Smolensk have been added. There is also a reported intension to increase cobalt-60 production at Indian PHWR reactors; and Nuclearelectrica Romania has announced a study of cobalt-60 production at its CANDU reactors at Cernavoda NPP. Currently, almost all of the world’s cobalt-60 is produced in CANDU Pressurised Heavy Water Reactors (PHWRs) and RBMK Light Water Graphite-moderated Reactors (LWGRs) of which there is a limited number. The greatest opportunity to significantly increase the availability of cobalt-60 is therefore to develop production in new reactor types. There are approximately 440 commercial reactors in operation of which more than 300 are Pressurised Water Reactors (PWRs). This has made PWRs the reactor platform of focus for future cobalt-60 production. In February 2020, Nordion announced that it was
partnering with Westinghouse to develop large-scale production of cobalt-60 in PWRs. Both Nordion and Westinghouse have since updated the irradiation market with the timeline of this important initiative and confirmation that progress has been made with technology development, licencing, manufacture of components and the recruitment of three utility companies that operate five reactors. Production of cobalt-60 in PWR’s would be highly scalable with the capacity to at least double existing worldwide production volumes from PWRs in the US alone. Other initiatives include the announcement in December
2021 that Framatome and Exelon Generation will cooperate to understand and develop solutions to produce cobalt-60 in PWRs operated by Exelon Generation (now Constellation).
Right:
A set of adjusters in the Secondary Irradiated Fuel Bay in preparation to separate individual cobalt-60 bundles Photo credit: Bruce Power/ Canadian Nuclear Isotope Council
Securing the critical supply of cobalt-60 The healthcare industry has relied on cobalt-60 since the 1960s when the demand for medical device sterilisation started to grow. The production of cobalt-60 in nuclear reactors remains critical to health care and will continue to be critical for the long term future. Although significant steps are underway to increase production, growing demand for healthcare means that new cobalt-60 supply will always be important. The road to engaging in cobalt-60 production is
complex. There are a number of design and engineering considerations, safety assessments, the need to understand the impact on reactor efficiency and operations, and many other regulatory and operational considerations. However, there is also a wealth of experience and willing partners who understand the importance of increasing cobalt-60 production. In addition to the provision of clean energy, the production of cobalt-60 in support of health care remains a highly positive contribution by the nuclear industry to societal wellbeing. ■
24 | May 2024 |
www.neimagazine.com
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