1. Management of Disused Sealed Radioactive
Sources
Date
By:
Alan Carolissen
Senior Manager: NLM
2. Background
2
• Proper management of disused sealed radioactive
sources a priority
– Developing countries: Poor accounting systems and/or lack of
expertise/funds
– Developed countries: Large quantities - Difficult to control.
• Disused High Activity Radioactive Sources (SHARS)
especially problematic
• No standard procedures or suitable technologies available
• Disused sources, including SHARS, kept in working
shields in storage facilities or places of earlier use – not
always under very secure or safe conditions
8. • Responsible radioactive
waste and spent/disused
sources in South Africa.
• Initial work outside SA
was on the smaller/lower
activity sources
• 1998 performed first
IAEA radium source
conditioning operation in
Ghana
• Since then about 15
countries done, mostly in
Africa.
NLM experience
8
Continues…
9. • Repair of SHARS units.
• SHARS source removal and
transfer for storage
• SHARS unit removal at
facilities and safeguarding
done in various countries
NLM experience
9
10. SHARS mobile hot cell development
• Identified the need for technology to handle SHARS
• In 2003 – concept of a mobile hot cell evaluated by international
team of experts (Canada, USA, UK, Belgium, South Africa)
• Necsa (South Africa) - 2003 - develop basic design for a mobile
conditioning unit (“hot cell”)
• Detail design and manufacturing from 2005
• Every phase evaluated by peer review team
• Funding provided by IAEA - additional support from US NNSA
through the IAEA Nuclear Security Fund.
• Demonstrated in 2007 – field operations since 2009
• Sudan, Tanzania, Uruguay
10
11. Design of Mobile Hot Cell
• Cell Components:
– Cell walls – Double cavity wall 1,55 m thick - filled with river
sand with density of 1,6 - Mild steel “shuttering” plates
– Working volume 1,6 m x 2,5 m x 3 m high
– Roof – 3 x 0,23 m thick concrete slabs
– Window – oval shaped steel container with polycarbonate
ends - filled with 50% ZnBr2
– Telescopic master-slave manipulators with 20 kg lifting
capacity
11
14. Design of Mobile Hot Cell
• Auxiliary Equipment
– Jib crane on inside
– Exhaust ventilation unit
– 3600 camera coverage on inside
– Table with tools, welding and leak testing equipment
– Lighting
• Long Term Storage Shield – designed by RWE Nukem (UK) and
design modified in 2011 for licensing as transport container (LANL
Areva) – 4 drawers with 10kCi capacity.
• A-frame crane over unit
• Transported in 2 x 20ft shipping containers
14
17. Management Approach
• Removal of heads from working unit
• Transport all units to conditioning site (centralized store)
• Transport unit into country – assemble and prepare for operation
• Removal of SHARS from working shields and transfer into long term
storage shield
– Partial dismantling of head/irradiator outside cell
– Placement inside cell and further dismantling
– Removal of SHARS
– Segregation of sources in terms of origin (country)
– Encapsulate in stainless steel capsules – welding and leak testing
– Placement into LTSS or Transport Container
– Stored safely and securely or repatriated
• Dismantle unit and return to SA
17
18. Logistics
• Equipment shipped to country in 2 x 20 ft ISO shipping
containers
• Total operation – 1 week to assemble and 1 week to
disassemble and work in-between depending on number of
sources to recover
18
30. Conclusion
• 3 Operations successfully completed
– Sudan
– Tanzania
– Uruguay
• Mobile Hot Cell proved itself as a very useful tool for
recovery of high activity sources – proved itself under
various conditions
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