2009-03-01
In September 2008, the Nuclear Regulatory Commission (NRC) held a
workshop on the security and continued use of cesium-137 chloride
(CsCl) sources. CsCl sources are widely used in irradiators to
sterilize human blood, in biomedical and industrial research, and for
calibration of radiation instrumentation and dosimetry. Gamma-ray
irradiation of lab animals by CsCl-containing devices is widely used in
hematology, immunology, and stem cell biology research.
CsCl sources have come under scrutiny from a security standpoint
because cesium is a compressed powder that is highly soluble in water
and dispersible as an aerosol. Alternatives such as x-ray irradiators
and cobalt-60 irradiators could be used in some cases, but not all; and
the cost of switching to these alternatives would be financially
prohibitive to most users.
During the September workshop, the NRC solicited comments from
stakeholders on a draft paper that discussed alternative CsCl sources
and technologies, a phase-out of CsCl, additional enhanced security
measures, and other potential future requirements. ASH submitted
comments urging the Commission to consider how the elimination of CsCl
sources would compromise care and research that leads to development of
clinical treatments for patients. ASH also shared these concerns with
the staff of Representative Edward Markey (D-MA) who has sponsored
legislation that would give the NRC authority to further regulate
radiation sources such as CsCl.
In November 2008, NRC staff submitted a memorandum outlining three
possible options for the Commission’s consideration regarding the
continued use and security of CsCl sources. The option recommended by
NRC staff for approval, and for which ASH advocated, suggests
maintaining current CsCl use in blood irradiation, biomedical research,
and calibration, while also advocating for developing enhanced security
systems for new and existing units and for developing a Commission
policy statement. This option also acknowledges that significant
impediments exist to any potential phase-out of CsCl and states that
there is insufficient information available to develop a technical
basis for rulemaking.
ASH was pleased that the NRC staff’s analysis and conclusions echoed
the Society’s concerns. ASH will continue to monitor this issue and
keep members updated on any future developments.
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