[Federal Register Volume 76, Number 142 (Monday, July 25, 2011)]
[Pages 44378-44383]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-18767]




Policy Statement of the U.S. Nuclear Regulatory Commission on the 

Protection of Cesium-137 Chloride Sources

AGENCY: Nuclear Regulatory Commission.

ACTION: Policy statement.


SUMMARY: The U.S. Nuclear Regulatory Commission (NRC or the Commission) 

is issuing a statement of policy on the protection of cesium-137 

chloride (CsCl) sources. This statement sets forth the Commission's 

policy regarding secure uses of these sources at the present and states 

the Commission's readiness to respond with additional security 

requirements, if needed, should the threat environment change. The 

purpose of this policy statement is to delineate the Commission's 

expectations for security and safety of these sources.

DATES: This policy statement is effective July 25, 2011.

ADDRESSES: You can access publicly available documents related to this 

document using the following methods:

     NRC's Public Document Room (PDR): The public may examine 

and have copied, for a fee, publicly available documents at the NRC's 

PDR, O1-F21, One White Flint North, 11555 Rockville Pike, Rockville, 

Maryland 20852.

     NRC's Agencywide Documents Access and Management System 

(ADAMS): Publicly available documents created or received at the NRC 

are available online in the NRC Library at http://www.nrc.gov/reading-rm/adams.html. From this page, the public can gain entry into ADAMS, 

which provides text and image files of the NRC's public documents. If 

you do not have access to ADAMS or if there are problems in accessing 

the documents located in ADAMS, contact the NRC's PDR reference staff 

at 1-800-397-4209, 301-415-4737, or by e-mail to [email protected].

     Federal Rulemaking Web Site: Public comments and 

supporting materials related to this policy statement can be found at 

http://www.regulations.gov by searching on Docket ID NRC-2010-0209. 

Address questions about NRC dockets to Carol Gallagher, telephone: 301-

492-3668; e-mail: [email protected].

FOR FURTHER INFORMATION CONTACT: Dr. John P. Jankovich, Office of 

Federal and State Materials and Environmental Management Programs, 

telephone: 301-415-7904, e-mail:

[[Page 44379]]

[email protected], or Dr. Cynthia G. Jones, Office of Nuclear 

Security and Incident Response, telephone: 301-415-0298, e-mail: 

[email protected].


I. Background

    Certain radioactive sources, including CsCl sources, have been 

identified by the International Atomic Energy Agency (IAEA) Code of 

Conduct on the Safety and Security of Radioactive Sources (Code of 

Conduct) (see http://www-pub.iaea.org/MTCD/publications/PDF/Code-2004_web.pdf) as sources that may pose a significant risk to individuals, 

society, and the environment if improperly handled or used in a 

malicious act. Consequently, the NRC has required additional security 

measures for Category 1 and 2 sources and considers it prudent to 

express its views on the safe and secure use of CsCl sources. The CsCl 

sealed sources are used in many applications that have significant 

societal benefits, most commonly in irradiators, calibrators, and in 

devices for biological and medical research.

    To develop its draft policy statement, the NRC initiated and 

completed a number of initiatives. A significant element of these 

initiatives was an Issue Paper which was published in the Federal 

Register on July 31, 2008 (73 FR 44780), and discussed with 

stakeholders in a public workshop held on September 29-30, 2008. The 

NRC also received numerous written comments on the Issues Paper. The 

oral and written comments as well as the transcript of the workshop, 

along with other relevant information, are accessible at http://www.nrc.gov/materials/miau/licensing.html#cesium. A study \1\ on the 

use and replacement of radiation sources, conducted by the National 

Research Council of the National Academies in 2008, recommended 

eliminating Category 1 and 2 CsCl sources from use in the United States 

and to the extent possible elsewhere. The National Research Council 

also recommended that replacement of some sources with alternatives 

should be implemented with caution, ensuring that essential functions 

that the sources perform are preserved.


    \1\ National Research Council of the National Academies, 

``Radiation Source Use and Replacement,'' The National Academies 

Press, Washington, DC, http://www.nap.org.


    The NRC prepared a draft policy statement, which described issues 

related to safety and security associated with IAEA Category 1 and 2 

CsCl sources \2\. The Draft Policy Statement was published for public 

comment in the Federal Register on June 29, 2010 (75 FR 37483). The 

intent of this document was to foster discussion about these issues and 

to solicit comments on the draft policy statement. The NRC held a 

public meeting on November 8-9, 2010, to solicit comments on the Draft 

Policy Statement. The public meeting was announced in the Federal 

Register on September 29, 2010 (75 FR 60149), as well as in two NRC 

press releases issued June 28, 2010 (No. 10-117), and October 5, 2010 

(No. 10-176). The public meeting included technical sessions with panel 

presentations, followed by facilitated discussion with the audience. 

The meeting was attended by the general public and representatives of 

licensees (users in the blood irradiation industry, biomedical research 

institutions, the pharmaceutical industry, and calibration 

laboratories), health and industry associations, source and device 

manufacturers, manufacturers of alternate technologies (x-ray and 

cobalt-60), and Federal and State government agencies. The NRC 

developed a public Web site, http://www.nrc.gov/materials/miau/licensing.html#cc, to make documents accessible relevant to the draft 

policy statement and to the public meeting.


    \2\ An IAEA Category 1 cesium-137 source contains a minimum of 

3000 Ci (100 TBq) and a Category 2 source contains a minimum of 30 

Ci (1 TBq). See http://www-pub.iaea.org/MTCD/publications/PDF/Code-2004_web.pdf.


    The NRC received written comments and a number of oral comments 

from the panelists and the audience at the public meeting. The majority 

of the comments supported the Draft Policy Statement. Many commenters 

recommended expanding the narrative regarding the areas of use of CsCl 

sources, as well as recommendations to clarify statements in the 

policy. The comments and the submissions provided valuable information 

for the formulation of this Policy Statement regarding the use of CsCl 

sources, security issues, and the diversity of impacts that licensees 

could experience as a result of potential further regulatory 

requirements. In addition, there were recommendations to include the 

IAEA Category 3 CsCl sources in certain selected types of use. All of 

the written and oral comments were considered when finalizing the 

Policy Statement \3\. None of the comments resulted in changes to the 

basic principles that are in the Policy Statement. The changes to the 

Draft Policy Statement are limited. In response to public comments, the 

Policy Statement contains expanded discussions of the use of CsCl 

sources in addition to clarifications. Changes were also made to 

address the new developments including issuance of the Radiation Source 

Protection and Security Task Force's (Task Force) quadrennial report 

(Task Force Report) and its implementation plan, and publication of the 

draft environmental impact statement by the U.S. Department of Energy 



    \3\ See Summary of Comments on the CsCl Draft Policy Statement 

and Staff Resolutions (ADAMS Accession No. ML110750506).


    In August 2010, the Task Force completed its quadrennial Task Force 

Report to the President and Congress (ADAMS Accession No. ML102230141). 

The Task Force Report addressed the security of all radioactive 

sources, but singled out the issue of CsCl sources in several of the 

recommendations. As a follow-up to the Task Force Report, the NRC 

developed an implementation plan for the Task Force Report (ADAMS 

Accession No. ML103050432) in December 2010. The NRC implementation 

plan defined the recommendations as tasks to be completed by the Task 

Force within the framework of their upcoming activities including the 

issue of CsCl sources. The Policy Statement is consistent with the 

conclusions and the recommendations of the Task Force Report.

    Disposal of CsCl sources is addressed in the Policy Statement. 

Regarding disposal of radioactive materials, the DOE published, in 

February 2011, for public comment a ``Draft Environmental Impact 

Statement for the Disposal of Greater-Than-Class C (GTCC) Low-Level 

Radioactive Waste and GTCC-Like Waste'' (see http://nepa.energy.gov/1653.htm). The Draft Environmental Impact Statement (DEIS) includes 

proposals for resolution of disposal issues for sealed sources, 

including CsCl sources. The Policy Statement recognizes the DOE's 

issuance of the DEIS and expresses the Commission's intent to monitor 

the DOE as it makes a decision on a GTCC disposal facility which will 

require an NRC license.

II. Policy Statement of the U.S. Nuclear Regulatory Commission on the 

Protection of Cesium-137 Chloride Sources

Statement of Policy

    The NRC issues this Policy Statement to set forth its policy on the 

secure uses of sealed sources containing CsCl and to describe potential 

Commission actions if changes in the security threat environment 

necessitate regulatory action. The Policy Statement also delineates the 


[[Page 44380]]

expectations for the secure and safe use of CsCl sources with activity 

levels of Category 1 and 2 as characterized by the IAEA Code of 


    It is the policy of the Commission that its mission of ensuring 

adequate protection of public health and safety, common defense and 

security, and the environment while enabling the use of radioactive 

materials for beneficial civilian purposes is best accomplished with 

respect to CsCl by implementing or promoting the following principles:

     The safety and security of IAEA Category 1 and 2 sources 

is an essential part of the NRC's mission;

     Licensees have the primary responsibility to securely 

manage and to protect sources in their possession from misuse, theft, 

and radiological sabotage;

     Adequate protection of public health and safety is 

maintained if CsCl sources are managed in accordance with the safety 

and security requirements of the NRC and the Agreement States.\4\ These 

requirements are based on vulnerability assessments of the various 

sources and follow the principles of the IAEA Code of Conduct;


    \4\ Agreement States are those States that have entered into an 

agreement with the NRC to assume authority under Section 274b of the 

Atomic Energy Act of 1954, as amended, to license and regulate by-

product materials (radioisotopes), source materials (uranium and 

thorium), and certain quantities of special nuclear materials.


     While these sources are adequately protected under the 

current NRC requirements, design improvements could be made that 

further mitigate or minimize the radiological consequences;

     The development and use of alternative forms of cesium-137 

(Cs-137), while not required for adequate protection, are prudent and 

the NRC intends to monitor these developments closely. In addition, the 

NRC recognizes that objective measures of `solubility' and 

`dispersibility' may need to be clarified as alternate forms of Cs-137 

are developed by manufacturers;

     The CsCl sources enable three specific classes of 

applications that benefit society: (a) Blood irradiation, (b) bio-

medical and industrial research, and (c) calibration of instrumentation 

and dosimetry;

     The NRC recognizes that currently there is no disposal 

capability for such commercial sources. The NRC considers it imperative 

to develop a pathway for the long-term storage and disposal of these 

sources whether or not alternative forms are developed; and

     The NRC monitors the threat environment and maintains 

awareness of international and domestic security efforts. In the event 

that changes in the threat environment necessitate regulatory action, 

the NRC, in partnership with its Agreement States, would issue 

additional security requirements, if necessary, to apply appropriate 

limitations for the use of CsCl in its current form.

Security and Control of Radioactive Sources

    Effective regulatory requirements and strong measures are currently 

in place for ensuring security and control of radioactive sources. 

After the terrorist events of September 11, 2001, the NRC and Agreement 

States issued security requirements mandating that licensees who 

possess IAEA Category 1 or 2 quantities of radioactive materials 

implement increased security and control measures to reduce the risk of 

malevolent use and intentional unauthorized access to radioactive 

material. The additional requirements enhanced and supplemented 

existing regulations in Title 10 of the Code of Federal Regulations (10 

CFR), Section 20.1801, ``Security of Stored Material,'' and 10 CFR 

20.1802, ``Control of Material Not in Storage,'' which are primarily 

intended to prevent or mitigate unintended exposure to radiation.

    Current security requirements include access controls and 

background checks for personnel; monitoring, detecting and responding 

to unauthorized access; delay; advance coordination with local law 

enforcement; and the tracking of transfers and shipments. The security 

requirements require licensees to establish and implement 

trustworthiness and reliability standards to determine who will have 

unescorted access to the radioactive material. An individual's 

trustworthiness and reliability is based upon a background 

investigation. The NRC and Agreement States have jointly developed 

materials protection and security regulatory requirements that reflect 

the experience gained through implementation of existing requirements.

    In addition, the NRC has implemented new regulatory requirements 

for import/export licensing and for reporting to the National Source 

Tracking System (NSTS), which increase accountability of Category 1 and 

2 radioactive material transactions and help to ensure that such 

transactions are only made by authorized entities.\5\ The NRC developed 

and maintains the NSTS, which provides information on sources from the 

time of manufacture through transportation and use to end-of-life 

disposition. The NSTS and other systems under development, such as the 

Web-Based Licensing and License Verification System which will permit 

verification of a license to possess radioactive sources, are key 

components of a comprehensive program for the security and control of 

radioactive materials. When complete, these systems will include 

information on all NRC, Agreement State, import/export licensees, and 

IAEA Category 1 and 2 radioactive sources.\6\


    \5\  See 10 CFR 20.2207.

    \6\ See http://www.nrc.gov/security/byproduct/nsts.html.


    The measures described above are in place to ensure the security of 

all Category 1 and 2 radioactive sources, including CsCl sources. Over 

the past six years, these measures have reduced the vulnerability for 

malevolent use of radioactive sources, including CsCl sources. In 

addition, the NRC and Agreement States are supporting the DOE's 

National Nuclear Security Administration (NNSA) voluntary program to 

retrofit existing CsCl irradiators with additional physical security 

enhancements and to incorporate these improvements into the designs of 

newly manufactured units. These modifications extend beyond current 

regulatory requirements. These efforts are often complemented by assist 

visits and tabletop exercises by NNSA experts at licensee facilities 

that allow participants to share best practices.

    The NRC and Agreement States also support the Federal Bureau of 

Investigation's ongoing Weapons of Mass Destruction (WMD) 

countermeasure effort to reach out to certain communities of licensees 

(including the CsCl irradiator licensee community). A critical aspect 

of this WMD countermeasure effort is information sharing through visits 

to licensees. These visits encourage communication and allow 

regulators, law enforcement, and licensees to gain an understanding of 

a licensee's security arrangements and how and when law enforcement 

would be engaged if there were a threat or a security event at a 

licensee's site.

    To maintain security of sources, the Energy Policy Act of 2005 

(EPAct) established the Task Force on Radiation Source Protection and 

Security to be chaired by the Chairperson of the Commission (or 

designee). The purpose of the Task Force is to evaluate and provide 

recommendations to the President and Congress periodically relating to 

the security of radiation sources in the United States from potential 

terrorist threats, including acts of sabotage, theft, or use of a 


[[Page 44381]]

source in a radiological dispersal device. The Task Force consists of 

representatives from 14 Federal agencies (11 of which were specified in 

the EPAct), the Organization of Agreement States, and the Conference of 

Radiation Control Program Directors. The Task Force issued its first 

report \7\ in 2006 and its quadrennial report \8\ in 2010. The 2010 

Task Force Report, in a number of its recommendations, addressed the 

following issues associated with CsCl sources: export, end-of-life 

management, options for disposal, voluntary replacement with 

alternative technologies, and potential discontinuation of use of CsCl 

sources, contingent upon the viability of alternative technologies and 

consideration of the threat environment. The Task Force also developed 

a plan to implement the recommendations of the report. The NRC's policy 

for CsCl sources is consistent with the recommendations of the Task 

Force reports.


    \7\ Report to the President and the U.S. Congress Under Public 

Law 109-58, The Energy Policy Act of 2005, The Radiation Source 

Protection and Security Task Force Report, ADAMS Accession No. 


    \8\ Report to the President and the U.S. Congress Under Public 

Law 109-58, The Energy Policy Act of 2005, The 2010 Radiation Source 

Protection and Security Task Force Report, ADAMS Accession No. 



    The NRC supports the security initiatives of international 

organizations (e.g., IAEA), and other countries, as well as the 

initiatives of Federal agencies aimed to further increase the 

protection of IAEA Category 1 and 2 sources both domestically and 

overseas (e.g., NNSA's Global Threat Reduction Initiative). The NRC 

participates in the development of such protective measures in various 

international forums and will consider their applicability for use 

within the United States if the threat environment changes, which could 

warrant additional protective security measures.

Uses of CsCl Sources

    The CsCl sources comprise approximately 3 percent of the IAEA 

Category 1 and 2 sources in the United States. In comments at the 

public meetings and in written submissions, members of the medical and 

scientific communities stated that these CsCl sources are essential due 

to their applications in blood irradiation, bio-medical and industrial 

research, and calibration of instrumentation and dosimetry, especially 

for critical reactor and first responder equipment. The CsCl is used 

for these applications because of the properties of the nuclide Cs-137, 

including its desirable single energy spectrum (662 keV), long half-

life, low cost, and moderate shielding requirements relative to other 

nuclides. The CsCl used in these applications is in a compressed powder 

form that is doubly-encapsulated in two stainless steel capsules to 

ensure safety and security in normal use. This physical form is used 

because of its high specific activity (gamma emission per unit volume) 

and manufacturability. However, the powder is highly soluble and 

potentially dispersible, which could present security concerns if not 

properly secured and used in a malevolent manner.

    Blood irradiation is medically essential to prevent transfusion-

associated Graft-Versus-Host disease and the vast majority of hospitals 

use only irradiated blood. The CsCl blood irradiators are used to 

irradiate over 90 percent of all irradiated blood because CsCl blood 

irradiators are the most reliable and efficient blood irradiation 

devices currently available.

    In biomedical research, CsCl irradiation has been used for over 40 

years in fields such as immunology, hematology, stem cell research, 

bone marrow transplantation, cancer research, in-vivo immunology, 

systemic drug research, chromosome aberrations, DNA damage/repair, 

human genome, and genetic factors. According to members of the medical 

community, the continuation of such research is crucial for advancing 

patient care, and for studies on medical countermeasures against 

radiation effects for the protection of the public, first responders 

and military personnel. For most research, there are no alternatives to 

Cs-137 irradiation because of the unique properties of Cs-137 

radiation, such as high dose rates with uniform fields of linear energy 

transfer. No alternative technologies that can effectively replace CsCl 

sources for biomedical research have yet been developed. Based on 

decades of use, including trial use of certain x-ray machines for 

irradiation, the biomedical research community considers the Cs-137 

irradiators optimal for providing effective, reliable, dependable, 

economical, and experimentally reproducible means of required health 

care equipment needed for research. According to the medical community, 

the results of previous research with Cs-137 irradiators cannot be 

compared to results obtained from other types of irradiation due to 

differences in the energy spectra and dose distribution of the 

radiation sources. Conversion factors between biomedical experimental 

results of x-ray versus gamma-rays do not exist. The use of alternative 

technologies would necessitate extensive research to re-validate 

research models of diseases that have already been established using 

irradiation devices containing Cs-137.

    The national and international systems of radiation measurements 

are based on the energy spectrum of Cs-137. All American National 

Standards Institute standards and their associated test-and-evaluation 

protocols for calibration of radiation detection, instrumentation, and 

personal dosimetry rely on the use of Cs-137. In addition, all U.S. 

Department of Homeland Security-related standards for calibration of 

first responder and emergency response equipment, such as personnel 

self-reading dosimeters, portal monitors, and portable survey 

instruments, also require the use of Cs-137 for calibration purposes. 

Cs-137 was selected by the national and the international community as 

the basis of calibration because of the optimal single energy spectrum 

of this nuclide and its long half-life. The National Institute of 

Standards and Technology (NIST) maintains the national measurement 

standards and calibrates the instruments for secondary laboratories 

which require the use of Cs-137. These instruments are then sent to 

secondary and tertiary laboratories that, in turn, calibrate the 

instruments for end users. This network of facilities ensures that 

every radiation detection instrument that is used in the country 

measures radioactivity and identifies isotopes correctly and is 

traceable to NIST.

Ensuring Secure Disposal for Disused CsCl Sources

    The disposal of CsCl radioactive sources, which are currently in 

use, is a challenge because of the high cost of disposal and the lack 

of commercial disposal facilities. The vast majority of the CsCl 

sources in use today are classified as greater-than-Class C low-level 

radioactive waste. Today, used and unwanted CsCl sources are stored 

safely and securely at the users' sites under the applicable NRC and 

Agreement State control and security requirements until options become 

available. To maintain source safety and security, the sites are 

routinely inspected in accordance with established NRC and Agreement 

State inspection procedures. The Commission considers it imperative to 

develop a pathway for the long-term storage and disposal of these 

sources because extended storage at licensee facilities increases the 

potential for safety and security issues. The NRC will continue to 

monitor Federal and State activities and private sector initiatives as 

medium- and long-term solutions are explored to address the need for

[[Page 44382]]

disposal and disposition of CsCl sources.

    The Low-Level Radioactive Waste Policy Amendments Act of 1985 

assigned responsibility for providing disposal of this type of waste to 

DOE. However, pending the availability of a disposal capability, the 

DOE is not responsible for accepting disused sources for storage, 

transportation or other activities related to disposal except under 

special circumstances.\9\ In February 2011, the DOE published the 

``Draft Environmental Impact Statement for the Disposal of Greater-

Than-Class C (GTCC) Low-Level Radioactive Waste and GTCC-Like Waste 

(DOE/EIS-0375D, DEIS)'' \10\ as required under the National 

Environmental Policy Act for public review and comment. The DOE stated 

that in the coming years it plans to analyze public comments on its 

DEIS and finalize disposal alternative(s) for greater-than-Class C low-

level radioactive waste, including CsCl sources. The Commission will 

monitor DOE as it makes a decision on a GTCC disposal facility, which 

will require an NRC license.


    \9\ Under specified circumstances, and pursuant to other 

authority and responsibility under the Atomic Energy Act of 1954, as 

amended, the DOE may recover excess or unwanted sealed sources 

(including CsCl sources) for reuse, storage or disposal that present 

threats to public health, safety or national security.

    \10\ See http://www.gtcceis.anl.gov/.


The NRC's Perspective on Further Security Enhancements

    The NRC believes that the current enhanced regulatory framework for 

security of radioactive sources has been very effective in enhancing 

and ensuring the security and control of IAEA Category 1 and 2 sources 

used in medical, industrial, and research activities in the United 

States. The NRC encourages stakeholders to take an active role in 

source security and continue their efforts in maintaining the current 

security environment. As is necessary and practical, and in response to 

any change in the threat environment, the NRC will work with other 

Federal agencies to further enhance the secure use of Cs-137 sources. 

The NRC recognizes that it is prudent to maintain awareness of the 

status of research to identify alternative forms of CsCl. The NRC will 

remain cognizant of these issues and appropriately consider whether 

there are safety and security benefits to further risk reduction. As 

part of the NRC's responsibility to ensure the security of these 

sources, the NRC, in coordination with its Federal partners, 

continuously monitors the national threat environment and is prepared 

to take further regulatory actions should this environment change. Just 

as it did following the events of September 11, 2001, the NRC is 

prepared to take immediate action such as issuance of additional 

security requirements with Orders or rulemaking, to address such 

security-related issues, if necessary.

    While the current security requirements and measures are adequate, 

the NRC encourages the source and device manufacturers to implement 

design improvements that further mitigate or minimize the radiological 

consequences of misuse or malevolent acts involving these sources. 

Accordingly, the NRC supports efforts by manufacturers to develop 

alternate forms of Cs-137 and to strengthen device modifications that 

could further reduce the risk of malevolent use associated with CsCl. 

The National Research Council of the National Academies issued a report 

\11\ that supported these efforts, recommended that the NRC consider 

the potential economic and social disruption that changes to the CsCl 

requirements could cause, and supported a research and development 

program for alternative ``matrices'' for high-activity Cs-137 sources, 

which could provide lower security hazards.


    \11\ National Research Council of the National Academies, 

``Radiation Source Use and Replacement,'' The National Academies 

Press, Washington, DC, http://www.nap.org.


    The NRC recognizes that objective measures of `solubility' and 

`dispersibility' may need to be clarified as alternate forms of Cs-137 

are developed by manufacturers. While it is outside the scope of the 

NRC's mission to conduct developmental research, the Commission 

encourages research to develop alternative chemical forms for large 

activity Cs-137 sources. Given the state of the current technology, and 

because a less dispersible form does not negate the risk or a 

potentially large cleanup and economic cost, the NRC believes that, for 

the near term, it is more appropriate to focus on continued enforcement 

of the United States security requirements and to mitigate risk through 

cooperative efforts and voluntary initiatives of industries that 

currently manufacture and use CsCl sources. While current NRC and 

Agreement State security requirements are in place to ensure the safety 

and security of these sources, additional voluntary security efforts by 

licensees and that of NNSA's security enhancement program help to 

enhance existing and future design improvements to further minimize the 

potential misuse or malevolent acts involving these sources.


    The NRC is continually working with its domestic and international 

partners to assess, integrate, and improve its security programs, and 

to make radiation sources more secure and less vulnerable to 

terrorists. The NRC and the Agreement States have the responsibility to 

ensure the safe and secure use and control of radioactive sources, 

including CsCl sources. Both the NRC and the Agreement States have met 

this responsibility through imposition of additional security 

requirements. The actions of the NRC and the Agreement States to date 

have resulted in a strong security program. The NRC recognizes that 

near term replacement of devices or CsCl sources in existing blood, 

research, and calibration irradiators is not practicable or necessary 

due to implementation of the additional security requirements and lack 

of a disposal capacity. Many medical, research, and emergency response 

stakeholders have stated that short term replacement would be 

detrimental to existing medical programs, on-going biomedical research, 

and homeland response activities, respectively. Therefore, the NRC 

continues to believe that the security of these facilities should be 

maintained and enhanced as practical through the implementation of the 

regulatory requirements and through voluntary actions such as the 

physical security enhancements of existing devices and future designs 

against intrusion. The NRC supports efforts to develop alternate forms 

of Cs-137 that would reduce the security risks and will monitor these 

developments. Regarding possible future regulatory actions affecting 

the use of IAEA Category 1 and 2 CsCl sources, the NRC would solicit 

public input in the development of any rule or guidance for the use of 

CsCl devices if additional security measures are considered. The NRC 

will continue to work with its Federal and State partners to ensure the 

safety and security of CsCl sources. In the event that changes in the 

threat environment necessitate regulatory action, the NRC, in 

partnership with the Agreement States, will be ready to issue 

additional security requirements to apply appropriate limitations for 

the use of CsCl, as necessary.

    Dated at Rockville, Maryland, this 19th day of July, 2011.

[[Page 44383]]

    For the Nuclear Regulatory Commission.

Annette L. Vietti-Cook,

Secretary of the Commission.

[FR Doc. 2011-18767 Filed 7-22-11; 8:45 am]