Skip Navigation LinksHome > Advocacy > Regulatory Affairs > Irradiation

Skip Navigation LinksHome > Advocacy > Regulatory Affairs > Irradiation

Analysis of NRC Report on Recommendations and Options for the Continued Use and Safety of Cesium-137 Chloride Sources – 1/13/09

The Nuclear Regulatory Commission has published a report to the commissioners on the strategy and regulatory options for the security and future use of cesium-137 chloride (CsCl) sources. In the report, the agency recommends that sources remain in use with continued and improved security. The report, which was released in November 2008, outlines three options developed by the agency and provides background information from research, a report from the CsCl subgroup on the “Radiation Source Protection and Security Assessment of Feasibility of Phasing out the use of CsCl in a Highly Dispersible Form,” and a public workshop held in September 2008. AABB was an active participant at the public workshop as a panelist and strongly expressed the concerns and issues of the membership — lack of a suitable alternative, little to no available funding to switch methodology and disruption to patient care.


Summary of Background Information

Stakeholder feedback received at the workshop and in comments submitted to the agency strongly indicated that near-term replacement of devices or CsCl sources in existing blood, research and calibration irradiators is not practical and would be disproportionately detrimental to patient health, longstanding research and emergency response capabilities. Alternatives to Cs-137 could be possible but are not currently available, and it is not certain whether it will be viable to produce less dispersible/soluble forms of Cs-137 for high-activity sources needed in CsCl irradiators. The end-of-life management of these sources, which is the responsibility of the government, is not mature and likely will not be for some time.


The NRC noted that a clear strategy for end-of-life management of these sources must be developed, and a significant research and development effort is needed to make viable alternative technologies cost-effective and widely available. The agency could work closely with domestic federal and international partners to enhance security regardless of any option and to conduct research to develop viable resolution of the solubility/dispersibility issue.


Summary of NRC’s Three Options

Taking this information into consideration, NRC proposed to the commissioners three options on the continued use of cesium-137 chloride sources:


Option 1: Maintain the fundamental elements of security and the normalcy of CsCl use in blood irradiation, biomedical research and calibration.


This option recognizes that significant obstacles exist to any potential phaseout of CsCl and that there is insufficient information available to develop a technical basis for rulemaking. It initiates a path forward toward further enhancing security of CsCl and resolving the obstacles identified. The implementation period is relatively short. Some of the actions can be started immediately, such as securing the largest sources, and additional actions will continue for two years for remaining high-risk CsCl sources.


Proposed actions to be conducted by the NRC to enhance security include the following:

·         Assess implementation of a voluntary hardening program for blood and research irradiators, and consider making it a requirement for existing devices through rulemaking.

·         Attain industry consensus for new blood irradiators to be delivered with hardening.

·         Work with the U.S. Department of Energy’s National Nuclear Security Administration and the Department of Homeland Security’s Domestic Nuclear Detection Office on potential hardening (to increase delay) for CsCl calibrators and assess potential security enhancements.

·         Continue to monitor the threat environment and issue new security requirements as necessitated by emerging risks.

·         Assess whether additional requirements are needed (e.g., tamper-proofing) through the ongoing enhanced security rulemaking process.

·         Interact with International Atomic Energy Agency and other international partners to promote and enhance CsCl security.

·         Engage federal partners in the development of a common set of criteria for dispersibility and other material properties related to mitigating the consequences of an RDD and anticipatory research for less soluble/dispersible forms of Cs-137.

·         Develop a strategy for end-of-life management of CsCl sources.


All actions, except long-term research, could be completed within two years.


Option 2: Initiate a process that would lead to phasing out CsCl in dispersible/soluble form in blood irradiators and replace it in existing and new devices with ceramic/glass form.


Replacement of the current form of CsCl would be feasible when two preconditions are resolved: (1) nonsoluble/dispersible forms become available requiring a research and development process to successfully scale up the activity level; and (2) a disposal pathway is established to transport and store the existing sources that are to be replaced. The development of an alternative form of Cs-137 is estimated to take at least four to five years, and the viability of the alternative is not assured. Consequently, the replacement program could begin after the fourth or fifth year (or when the disposal pathway becomes available). Establishment of a disposal site is estimated to take four years or more.


Proposed actions to be conducted by the NRC staff:

·         Establish acceptance criteria for dispersibility because currently there are no objective, quantifiable techniques that would define and measure dispersibility.

·         Interact with federal partners to facilitate the availability of the disposal pathway.

·         Interact with federal partners to fund research to develop a nondispersible/nonsoluble form of Cs-137.

·         Initiate rulemaking to require nondispersible/nonsoluble material for CsCl sources or develop incentives for voluntary licensee actions.

·         Interact with IAEA and other international partners to promote and enhance CsCl security.


The implementation period is relatively long.


Option 3: Extends the ban that is discussed in option 2 to include biomedical research and calibration, requiring the use of alternative forms of Cs-137.


The preconditions outlined in option 2 also must be met for implementation of the ban. The specific actions to be conducted by the NRC staff are identical but on a larger scale.


NRC Recommendation

After carefully considering all the information, the NRC staff recommended option 1 for the continued security of these facilities through the use of increased controls and continued support of federally funded programs to harden the existing devices against intrusion. The recommendation was based on an assessment of the advantages, disadvantages and implementation period of the three options and the information gathered from staff analysis, stakeholder inputs, a public workshop, site visits and other sources. Option 1 also takes into account that viable alternatives may not be successfully developed, but it lays the foundation for a path forward that may reduce the risks associated with CsCl sources. In addition, the irradiator should be hardened at the manufacturer’s facility for new licensees and existing licensees seeking a newly manufactured irradiator.



Impact to Blood Establishments
If the commissioners agree with the NRC’s recommendation, the impact to blood establishments would be very minimal because there would be no changes to blood irradiation practices. The only disruption would be the time that it takes for the irradiator manufacturer to “harden” the irradiator, and this would be performed at the facility. No additional funds would be incurred by the establishment to switch to a different irradiation source.