a

GAO

United States Government Accountability Office

Report to the Chairman, Committee on 

Energy and Natural Resources, U.S. 

Senate

September 2005 NUCLEAR SECURITY

DOE Needs Better 

Information to Guide 

Its Expanded 

Recovery of Sealed 

Radiological Sources

GAO-05-967
What GAO Found

United States Government Accountability Office

Why GAO Did This Study

Highlights

Accountability Integrity Reliability

www.gao.gov/cgi-bin/getrpt?GAO-05-967.

To view the full product, including the scope 

and methodology, click on the link above. 

For more information, contact Gene Aloise at 

(202) 512-3841 or aloisee@gao.gov. 

Highlights of GAO-05-967, a report to the 

Chairman, Committee on Energy and 

Natural Resources, U.S. Senate 

September 2005

NUCLEAR SECURITY

DOE Needs Better Information to Guide 

Its Expanded Recovery of Sealed 

Radiological Sources 

DOE has increased emphasis on its source recovery project and begun the 

process of identifying disposal options for GTCC waste. DOE transferred 

project responsibilities to another office that has given the project higher 

priority and accelerated DOE’s recovery efforts. DOE exceeded an earlier 

goal for recovering sources and has now collected over 10,800 of them. This 

recovery has been facilitated by additional project funding support and 

DOE’s resolving a shortage of storage space for certain sources. In May 

2005, DOE issued a notice of intent to prepare an environmental impact 

statement to assess GTCC waste disposal options; however, DOE has not yet 

determined when a disposal site might be made available. 

DOE has expanded the scope of its recovery effort to include non-GTCC 

waste from sealed radiological sources, a change that could increase DOE 

expenditures. DOE recovered and commercially disposed of 443 of these 

sources from a bankrupt firm, at a cost to DOE of about $581,000. Given 

that unwanted sources in storage present higher vulnerabilities, DOE might 

need to recover more of them in the future if the commercial disposal site 

that currently accepts this non-GTCC waste from most states ceases to do so 

as planned in 2008. Lacking a commercial disposal option, DOE anticipates 

storing this waste, rather than disposing of it at DOE sites, because, among 

other reasons, it does not want to undermine the responsibility the Congress 

gave the states to provide disposal availability for non-GTCC waste. 

DOE lacks information that would assist its efforts to identify and recover 

unwanted sealed radiological sources that may pose a safety and security 

risk. DOE has useful information on the sources in its possession, including 

recovered sources. However, DOE does not know how many sources might 

need recovery and how much disposal capacity is needed for GTCC waste. 

NRC is developing a national source tracking system that would not be 

useful for DOE’s source recovery efforts because it is only designed to track 

individual sources with high radioactivity. According to DOE, nearly all of 

the sites where it has recovered sources contained individual sources with 

lesser radioactivity than would be tracked by NRC, but their combined 

radioactivity posed enough of a risk to warrant their recovery by DOE. 

DOE Personnel Packaging a Sealed Radiological Source in a Disposal Drum 

Source: GAO.

Pictured left to right: A sealed source being removed (in pliers) from a shielded storage container at 

a recovery site; the interior of a multifunction container used for transport, storage, and disposal; and 

the process of closing the steel pipe component after the source has been loaded into the 

multifunction container.

Concerns remain over the control 

of sealed radiological sources, 

widely used in many industrial and 

medical devices and applications. 

The Nuclear Regulatory 

Commission (NRC), the 

Department of Energy (DOE), and 

states have responsibilities for 

ensuring the safe and secure use 

and eventual disposal of these 

sources as low-level radioactive 

wastes. DOE must ensure disposal 

availability for greater-than-class C 

(GTCC) waste; states must do so 

for non-GTCC waste, that is, 

classes A, B, and C waste. NRC 

and DOE also collaborate to 

identify and recover unwanted 

sources that are not safe or secure. 

GAO examined DOE’s (1) efforts to 

recover unwanted sources and 

develop a GTCC waste disposal 

option, (2) actions to recover and 

dispose of non-GTCC source waste, 

and (3) ability to identify sources 

for recovery and disposal. 

What GAO Recommends

GAO recommends that DOE and 

NRC evaluate and report on the 

cost implications of DOE’s 

recovery and disposal of non-GTCC 

waste, options to recoup these 

DOE costs from licensees, the 

feasibility of using DOE disposal 

sites, and how a national source 

tracking system can be designed 

and implemented to improve DOE’s 

recovery and disposal efforts. DOE 

generally supported GAO’s 

recommendations. NRC found the 

report well written and balanced, 

but did not agree or disagree with 

GAO’s recommendations. 
Page i GAO-05-967 Security of Unwanted Radiological Sources

Contents

Letter 1

Results in Brief 5

Background 8

DOE Has Increased Emphasis on Its Source Recovery Project and 

Begun Assessing Options for Disposing of GTCC Waste 13

DOE Expanded the Scope of Its Source Recovery Project to Include 

Non-GTCC Waste, Which Could Increase Project 

Expenditures 25

DOE Lacks Information to Better Identify Unwanted Sealed 

Radiological Sources That May Need Recovery 31

Conclusions 37

Recommendations for Executive Action 37

Agency Comments and Our Evaluation 38

Appendixes

Appendix I: Scope and Methodology 43

Appendix II: Selected Sealed Radiological Source Devices and Their 

Potential Waste Classes 47

Appendix III: Comments from the Department of Energy 50

Appendix IV: Comments from the Nuclear Regulatory Commission 53

Appendix V: GAO Contact and Staff Acknowledgments 56

Tables Table 1: IAEA High-risk Categories of Sealed Radiological 

Sources 10

Table 2: Summary of DOE-Recovered Sealed Radiological Sources, 

by Radionuclide, as of June 7, 2005 15

Table 3: DOE-Recovered Sealed Radiological Sources, by Their 

IAEA Source Category, as of June 7, 2005 35

Table 4: Selected Sealed Radiological Source Devices and Their 

Potential Waste Classes 47

Figures Figure 1: Loss of Control of Sealed Radiological Sources 9

Figure 2: Source Recovery Project Personnel Remove a Sealed 

Radiological Source and Repackage It into a 

WIPP-Acceptable Disposal Drum 21

Figure 3: Relative Size of a Sealed Radiological Source and Typical 

Disposal Drums 22
Contents

Page ii GAO-05-967 Security of Unwanted Radiological Sources

Figure 4: A Cross Section of a Nuclear Gauge, and Leveling Gauges 

Returned to a Manufacturer 23

Figure 5: Interior Views of Two 55-Gallon Disposal Drums, One 

with a Large Opening for an Entire Disused Device and 

the Other with a Narrow Pipe Opening for Only 

Sources 24

Abbreviations

CRCPD Conference of Radiation Control Program Directors

DOE Department of Energy

EIS environmental impact statement

GTCC greater-than-class C

IAEA International Atomic Energy Agency

NNSA National Nuclear Security Administration

NRC Nuclear Regulatory Commission

WIPP Waste Isolation Pilot Plant

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Page 1 GAO-05-967 Security of Unwanted Radiological Sources

United States Government Accountability Office

Washington, D.C. 20548

A

September 22, 2005 Letr

The Honorable Pete V. Domenici

Chairman, Committee on Energy and 

Natural Resources

United States Senate 

Dear Mr. Chairman:

The regulatory control and tracking of sealed radiological sources in the 

possession of academic, government, industrial, medical, and utility 

entities that are licensed to use them in devices and applications continues 

to evolve. These sources contain radioactive material encapsulated, or 

sealed, in metal to prevent its dispersal. The small size and portability of 

sealed radiological sources, however, make them susceptible to misuse, 

improper disposal, and theft. If some types of sealed radiological sources 

fell into the hands of terrorists, they could be used in fabricating crude but 

potentially dangerous radiological weapons, commonly called dirty bombs. 

In general, a dirty bomb is produced by packaging explosives, such as 

dynamite, with radioactive material, which would be dispersed when the 

bomb was activated. 

There are an estimated 2 million devices containing sealed radiological 

sources in use throughout the United States,1

 and as many as one-quarter of 

them, or up to 500 thousand, may no longer be needed. However, only some 

of these sources are considered particularly attractive for producing dirty 

bombs because, among other things, they contain more concentrated 

amounts of certain nuclear material, such as americium-241, cesium-137, 

plutonium-238, and strontium-90. Depending on the type, form (e.g., solid 

or powder), amount, and concentration of the radioactive material 

dispersed in a malevolent act, the released material could cause radiation 

sickness for people nearby as well as significant economic costs and 

serious social disruption associated with the evacuation and subsequent 

cleanup of the contaminated area. Even without an intentional act, the 

inadvertent loss of a sealed radiological source can also lead to radiation 

exposure, high decontamination costs, and public panic. For example, in a 

1983 incident, a Texas company sold a cancer treatment machine 

containing a sealed radioactive source to a clinic in Mexico. The device was 

1

This estimate was first in J.O. Lubenau and J.G. Yusko, “Radioactive materials in recycled 

metals—an update,” Health Physics, Volume 74, No. 3 (March 1998) p. 297. 
Page 2 GAO-05-967 Security of Unwanted Radiological Sources

subsequently stolen, and the source was accidentally melted with other 

metals to form steel reinforcing rods that were imported into the United 

States and eventually used to build 37 homes and businesses. The steel 

rods were encased in concrete and thus were naturally shielded, but the 

incident caused public concern, costly decontamination, and increased 

regulatory inspections. 

The Nuclear Regulatory Commission (NRC) and the Agreement States2

 are 

responsible for regulating the use of sealed radiological sources and other 

radioactive materials, from creation to disposal, in a way that ensures the 

public health and safety. They do so through a combination of regulatory 

requirements, licensing, inspection, and enforcement. Under the Atomic 

Energy Act of 1954, NRC also is responsible for issuing rules, regulations, 

or orders to promote the common defense and security. As we reported in 

August 2003, NRC and the Agreement States disagreed about the 

appropriate state role in the regulation of sealed radiological source 

security.3

 According to NRC, it and the Agreement States are currently 

working together to implement increased regulatory requirements on 

licensees that possess sealed radiological sources that are of security 

concern. 

After a licensee determines that a sealed radiological source is no longer 

useful, the source can be returned to the manufacturer or supplier, 

transferred to another licensee, stored to allow for a natural decrease in 

radioactivity, or sent to a commercial waste disposal facility. Once the 

source is packaged for disposal, the disposal container is put into a waste 

class. NRC defines the four types of low-level radioactive waste (i.e., waste 

not classified as high-level waste, such as spent fuel from nuclear power 

plants) as classes A, B, C, and greater-than-class C (GTCC).4

 The type of 

radionuclide (e.g., americium-241) and the concentration of radioactivity 

2

The Agreement States system was formed by section 274 of the Atomic Energy Act of 1954, 

as amended (42 U.S.C. § 2021). This section of the act allows NRC to relinquish certain parts 

of its authority to Agreement States, of which there are 33, to license and regulate certain 

radioactive materials. NRC retains regulatory responsibility over licensees in the other 17 

states, and over other activities, such as regulation of all nuclear power plants. 

3

GAO, Nuclear Security: Federal and State Action Needed to Improve Security of Sealed 

Radiological Sources, GAO-03-804 (Washington, D.C.: Aug. 6, 2003). 

4

10 C.F.R. § 61.55.
Page 3 GAO-05-967 Security of Unwanted Radiological Sources

(often measured in curies per gram),5 are considered in determining the 

waste class of the radioactive material, which carries progressively more 

stringent requirements for disposal from class A to GTCC waste. NonGTCC waste, including classes A, B, and C waste (e.g., contaminated soil, 

laboratory equipment, exit signs containing tritium, and some sealed 

radiological sources) generally can be disposed of by shallow burial at 

existing commercial low-level radioactive waste disposal sites. However, 

GTCC waste (e.g., activated metals,6

 sealed radiological sources, and other 

highly radioactive waste) will generally require a different type of disposal. 

Under the Low-Level Radioactive Waste Policy Act of 1980, as amended,7

the states and federal government were given separate responsibilities for 

providing disposal availability for these wastes. States were made 

responsible for providing disposal availability for non-GTCC waste, and the 

Department of Energy (DOE) was given the responsibility of providing 

disposal for GTCC waste. Non-GTCC waste must be disposed of in a facility 

licensed by either NRC or an Agreement State, but only NRC can license a 

facility for GTCC waste. As an incentive for states to manage waste on a 

regional basis, the Congress consented to the formation of interstate 

agreements, known as compacts, and granted compact member states the 

authority to exclude low-level radioactive waste from other compacts and 

unaffiliated states.8

Even though states have not developed any new disposal sites for low-level 

radioactive waste since passage of the act, we reported in June 2004,9

 that 

disposal availability for non-GTCC waste was adequate in the short term, 

but that federal oversight was needed to identify any future shortfalls. 

5

A curie is a measure of the rate of radioactive decay; it is equivalent to the radioactivity of 1 

gram of radium or 37 billion disintegrations per second. 

6

As a result of reactor operations, portions of the reactor barrel and other stainless steel 

components near the fuel assembly become highly radioactive. The majority of this waste is 

generated when nuclear power plants are decommissioned, although some waste may result 

from maintenance activities performed before decommissioning. There are presently 103 

active and 24 decommissioned nuclear power plants in the United States.

7

Pub. L. No. 96-573, as amended by Pub. L. No. 99-240, codified at 42 U.S.C. §§ 2021b-2021j.

8

There are 10 compacts comprised of 43 states and 7 unaffiliated states as well as the 

District of Columbia and Puerto Rico.

9

GAO, Low-Level Radioactive Waste: Disposal Availability Adequate in the Short Term, 

but Oversight Needed to Identify Any Future Shortfalls, GAO-04-604 (Washington, D.C.: 

June 9, 2004).
Page 4 GAO-05-967 Security of Unwanted Radiological Sources

There are currently three commercial disposal sites that collectively serve 

the nation’s non-GTCC waste disposal needs.10 A shortfall in disposal 

availability for the higher radioactive non-GTCC waste (classes B and C 

waste), however, could occur by mid-2008, if South Carolina follows 

through with plans to restrict access to its Barnwell disposal site to only 

the 3 member states of the Atlantic Compact. This restriction would mean 

that licensees in the 36 states that are currently allowed to use this disposal 

site would be denied access to it, and under current conditions, they would 

have no alternative option to dispose of their higher radioactive non-GTCC 

waste. Regarding GTCC waste disposal, we reported in April 200311 that 

DOE had not made progress toward providing for the permanent disposal 

of GTCC waste because doing so was not a priority at the time.

Given the lack of disposal options for GTCC waste and the public health, 

safety, and national security concerns about unwanted sealed radiological 

sources at licensee sites around the country, DOE, in collaboration with 

NRC, has been recovering, taking title of, and storing sources—primarily at 

its Los Alamos National Laboratory. DOE has been taking these actions 

through its Off-Site Source Recovery Project, which has been operated by 

Los Alamos National Laboratory personnel since the late-1990s. In June 

1999, NRC and DOE entered into a memorandum of understanding 

describing their respective roles and responsibilities for addressing the 

problem of unwanted and uncontrolled sealed radiological sources, often 

referred to as “orphan sources.” This memorandum formalized agreements 

reached between these agencies in 1992 to have DOE begin recovering and 

storing unwanted sealed radiological sources because DOE had yet to 

develop a disposal site for GTCC waste. Since then, DOE has routinely 

recovered, from licensees that request such a collection, sealed 

radiological sources that when packaged for disposal would be classified 

as GTCC waste. Many of these unwanted sources, such as plutonium-239, 

were originally derived from defense programs and loaned to colleges and 

universities that no longer want them. DOE, at the request of NRC, also 

10The commercial disposal site in Barnwell, South Carolina, is available to the 3 member 

states of the Atlantic Compact and 36 other states that are currently allowed to use this site 

for all non-GTCC waste. The commercial disposal site in Richland, Washington, serves only 

the 8 member states of the Northwest Compact and the 3 member states of the Rocky 

Mountain Compact for all non-GTCC waste. A third commercial disposal site in Utah is 

available to all states, except the Northwest Compact member states, for the disposal of 

only class A waste. 

11GAO, Nuclear Nonproliferation: DOE Action Needed to Ensure Continued Recovery of 

Unwanted Sealed Radioactive Sources, GAO-03-438 (Washington, D.C.: Apr. 15, 2003).
Page 5 GAO-05-967 Security of Unwanted Radiological Sources

recovers sources that are in the possession of licensees that are no longer 

able to ensure their safety and security. In our April 2003 report, we found 

that while DOE’s source recovery project had collected more than 5,000 

sources, the project faced the following three problems that could hinder 

future recovery efforts: questionable long-term commitment to the 

program of DOE’s Office of Environmental Management, inadequate 

storage capacity that meets the higher security requirements for sealed 

radiological sources containing plutonium-239, and DOE’s inability to store 

sealed radiological sources containing strontium-90 and cesium-137. 

In this context, we examined (1) the status of DOE’s efforts to recover 

unwanted sealed radiological sources and to develop a disposal option for 

GTCC waste, (2) DOE actions taken to recover and dispose of non-GTCC 

waste from sealed radiological sources, and (3) the extent to which DOE 

can identify unwanted sealed radiological sources for recovery and 

disposal. 

To conduct our work, we reviewed pertinent information in existing 

databases and published reports and interviewed officials from federal and 

state agencies, professional organizations, and representatives from 

entities that are licensed to possess sealed radiological sources. More 

specifically, we examined DOE’s efforts to recover unwanted sealed 

radiological sources and the databases maintained by DOE and NRC to 

inventory some of these materials. We assessed the reliability of these data 

and determined that they were sufficiently reliable for the purposes of this 

report. We also used structured interviews of licensees and commercial 

waste brokers that possess unwanted sealed radiological sources and 

reviewed their waste forms to obtain an understanding of how these 

materials are classified, and what challenges might be faced if there is no 

disposal option availability for them in the future. We excluded some 

radioactive wastes from our review because the radioactive materials are 

already under higher security, such as at nuclear power plants and DOE 

facilities, or because they present a lower security risk, such as class A 

waste. We conducted our review between June 2004 and September 2005 in 

accordance with generally accepted government auditing standards. A 

more detailed description of our methodology is provided in appendix I.

Results in Brief DOE has increased emphasis on its source recovery project and begun the 

process of identifying disposal options for GTCC waste. Specifically, DOE 

transferred responsibilities for source recovery from its Office of 

Environmental Management to its National Nuclear Security 
Page 6 GAO-05-967 Security of Unwanted Radiological Sources

Administration (NNSA) to better respond to both domestic and 

international threats posed by unwanted sealed radiological sources. DOE 

was able to recover 5,529 of these sources within 18 months, exceeding a 

recovery goal established in October 2002 and more than doubling the 

number of sources recovered since 1996. As of June 7, 2005, DOE had 

collected a total of 10,806 sealed radiological sources and plans to continue 

recovering sources at least until there is a permanent disposal option for 

GTCC waste. DOE’s accelerated recovery efforts have been supported 

through continued annual and supplemental appropriations. The recovery 

of these unwanted sealed radiological sources was also facilitated by 

DOE’s resolution of some problems with storage availability for certain 

types of sources. For example, DOE was able to recover and provide 

storage for over 260 plutonium-239 sources that licensees had registered 

for collection; however, some new issues have arisen that are preventing 

DOE from recovering the more than 100 of these sources that still remain at 

licensee sites. Finally, DOE has begun identifying disposal options for 

GTCC waste. In May 2005, DOE issued a notice of its intent to prepare an 

environmental impact statement assessing various disposal options for 

GTCC waste. In preparing this document, DOE plans to gather information 

on the amount of GTCC waste that might be generated over the next 30 to 

50 years; however, making useful projections will be difficult because, 

among other things, no national database tracks the volume of GTCC 

materials or waste. Further, DOE has not yet determined when a 

permanent GTCC waste disposal site might be available because of 

uncertainties surrounding what alternatives will be available to DOE after 

it completes the assessment of the various disposal options for this waste. 

DOE has expanded the scope of its source recovery project to include nonGTCC waste from unwanted sealed radiological sources—a change that 

could increase recovery project expenditures if DOE needs to recover and 

dispose of more of this waste in the future. DOE has already recovered and 

commercially disposed of non-GTCC waste from some licensees that could 

no longer ensure the safety and security of their unwanted sealed 

radiological sources. For example, in fiscal year 2004, at the request of 

NRC, DOE recovered from a bankrupt firm and commercially disposed of 

443 mostly cesium-137, sealed radiological sources at a cost of 

approximately $581,000. Moreover, DOE may need to begin recovering 

greater quantities of non-GTCC waste from unwanted sealed radiological 

sources if licensees in most states have no access to commercially dispose 

of it in the future. Domestic and international experts contend that the lack 

of disposal availability for unwanted sealed radiological sources makes 

them more vulnerable to abandonment, misplacement, and theft that would 
Page 7 GAO-05-967 Security of Unwanted Radiological Sources

pose a safety and security risk. If DOE needs to recover more of these types 

of sources, source recovery project expenditures may increase unless DOE 

can recoup some of its costs from licensees that could otherwise pay for 

disposal if a commercial disposal option were available. In the absence of 

any commercial disposal option for the non-GTCC waste that DOE collects, 

the department anticipates indefinitely storing this waste. DOE’s current 

policy is to not use its own sites for disposing of this waste because, among 

other reasons, it does not want to undermine the responsibility that the 

Congress gave to the states for providing disposal availability for nonGTCC waste. We are recommending that DOE and NRC collaborate in 

evaluating and reporting on the potential cost implications of expanding 

DOE’s recovery and disposal of non-GTCC waste from sealed radiological 

sources, options to recoup DOE costs from licensees that may have no 

disposal option, and the feasibility of disposing of this waste at DOE sites.

DOE’s ability to identify unwanted sealed radiological sources that may 

pose a safety or security risk is limited by a lack of information needed to 

guide its recovery and disposal efforts. DOE has useful inventory data only 

on the sealed radiological sources in its possession, including those 

recovered from licensees. This inventory captures, among other things, 

information on the status of each source, including whether it is in active 

use, is inaccessible, is in storage for potential future use, or is packaged for 

disposal. However, DOE does not have comparable information on the 

sealed radiological sources in the possession of licensees that might need 

recovery in the future because NRC and the Agreement States do not 

centrally collect this information from them. NRC has recently issued a 

proposed rule that will allow it to establish a national system to track the 

possession and movement of some individual sealed radiological sources 

that present a potential risk to individuals, society, and the environment 

because of their high levels of radioactivity. This proposed rule is 

consistent with the recently enacted Energy Policy Act of 2005,12 which, 

among other things, requires NRC to establish a tracking system and a task 

force to evaluate and report on radiation source protection and security 

concerns. However, as presently designed, this system would only track 

individual sources with high radioactivity concentrations and would not 

include essentially all of the sources of lesser radioactivity that DOE has 

recovered. According to DOE, over 90 percent of the licensee sites where 

sources were recovered contained individual sources of lesser radioactivity 

than would be individually tracked by NRC, yet their combined 

12Pub. L. No. 109-58, 119 Stat. 594 (2005).
Page 8 GAO-05-967 Security of Unwanted Radiological Sources

radioactivity concentration posed enough of a safety and security risk to 

warrant their recovery by DOE. As a result, this proposed national source 

tracking system would be of little use to DOE in its efforts to plan and 

budget for the recovery and disposal of unwanted sealed radiological 

sources. We are recommending that DOE and NRC collaborate on 

evaluating and reporting on how a national source tracking system can be 

designed and implemented to improve DOE’s ability to identify unwanted 

sealed radiological sources that may need DOE recovery and disposal.

DOE and NRC provided comments on a draft of this report. DOE stated 

that it generally supports all of our recommendations. Moreover, DOE 

commented that we had correctly reported the department’s position with 

regard to issues discussed in this report. In addition, DOE affirmed the 

need to improve the national source tracking system to assist the 

department in identifying and recovering unwanted sources from outside 

the department that pose a potential safety and security risk. NRC stated 

that overall our report was well written and balanced. NRC did not 

specifically agree or disagree with our recommendations. However, NRC 

expressed concerns that any changes to the design of its national source 

tracking system at this time could be extremely burdensome on licensees 

and the agency and would yield little, if any, practical benefit. Nevertheless, 

NRC stated that it will continue to seek comments on the inclusion of 

sources of lower radioactivity in its national source tracking system 

because licensees possessing large quantities of these sources could 

present a security concern. 

Background The loss of control of sealed radiological sources can arise from their 

abandonment, misplacement, or theft. In such cases, there is a risk of either 

the inadvertent or intentional malevolent human exposure to radioactive 

materials in these sources. Figure 1 shows a graphic representation of the 

ways in which the loss of control of sealed radiological sources can occur. 
Page 9 GAO-05-967 Security of Unwanted Radiological Sources

Figure 1: Loss of Control of Sealed Radiological Sources 

Since September 11, 2001, international and U.S. agencies have taken 

additional steps to increase the safety and security of radioactive materials, 

particularly sealed radiological sources. Between 2002 and 2003, the 

International Atomic Energy Agency (IAEA)13 held various meetings and 

conferences to discuss how the agency’s Code of Conduct on the Safety 

and Security of Radioactive Sources might be revised in light of new 

security concerns. One result of these gatherings was the development of a 

categorization scheme for sealed radiological sources in terms of the 

13IAEA was established within the United Nations in 1957. IAEA works with its member 

states; 138 countries, including the United States; and multiple other partners to promote 

safe, secure, and peaceful nuclear technologies. 

Source: IAEA, Strengthening Control Over Radioactive Sources in Authorized Use and Regaining Control Over Orphan Sources:

National Strategies, IAEA-TECDOC-1388 (Vienna, Austria: February 2004) p. 9.

Loss of Control of a Radioactive Source

Loss of, or damage 

to, sources

Misplaced

Forgotten

Accidents

Theft

Illegal purchase

Legal purchase

Illegal sale for 

profit

Avoidance of costs 

of ownership (e.g., 

dumping to avoid 

disposal fees)

Extortion

Terrorism

Individual’s intent 

to harm other(s)

(Sabotage)

Inadvertent Intentional

Damage Acquisition

Malevolent Motive Financial 
Page 10 GAO-05-967 Security of Unwanted Radiological Sources

potential risks associated with their malevolent uses.14 The first three of the 

five source categories identified by IAEA, which are considered to pose the 

most significant risk to individuals, society, and the environment, are listed 

in an annex to the Code of Conduct. The Code of Conduct recommends that 

IAEA member states establish a national registry that tracks, at a minimum, 

the first two source categories. Table 1 contains a listing of the 

radionuclides and their curie levels that are presented in the IAEA Code of 

Conduct.

Table 1: IAEA High-risk Categories of Sealed Radiological Sources

Source: IAEA, Code of Conduct on the Safety and Security of Radioactive Source (Vienna Austria: January 2004) Annex I, Table 1, p. 16.

a

A curie is a measure of the rate of radioactive decay; it is equivalent to the radioactivity of 1 gram of 

radium or 37 billion disintegrations per second.

14IAEA, Categorization of Radioactive Sources, TECDOC-1344 (Vienna, Austria: July 2003). 

IAEA defined five categories of radioactive sources in this 2003 document. The agency 

based its categorization framework on the health effects of exposure to the radioactive 

materials in the sources and did not fully take into account the range of impacts that could 

result from accidents or malicious acts involving radioactive sources. 

Radionuclide

Category 1

(curies)a

Category 2

(curies)a

Category 3

(curies)a

Americium-241 2,000 20 2

Americium-241/Beryllium 2,000 20 2

Californium-252 500 5 0.5

Cesium-137 3,000 30 3

Cobalt-60 800 8 0.8

Curium-244 1,000 10 1

Gadolinium-153 30,000 300 30

Iridium-192 2,000 20 2

Plutonium-238 2,000 20 2

Plutonium-239/Beryllium 2,000 20 2

Promethium-147 1,000,000 10,000 1,000

Radium-226 1,000 10 1

Scandium-75 5,000 50 5

Selenium-75 5,000 50 5

Strontium-90 30,000 300 30

Thulium-170 500,000 5,000 500

Ytterbium-169 8,000 80 8
Page 11 GAO-05-967 Security of Unwanted Radiological Sources

In May 2003, a DOE/NRC interagency working group—which was formed 

to address security concerns over the radioactive materials that could be 

used in a radiological dispersal device—issued a report that, among other 

things, recommended that actions be taken to develop a national threat 

policy based on vulnerability assessments, a national source tracking 

system, and an integrated national strategy for disposing of unsecured 

sealed radiological sources.15 Following this DOE/NRC report, NRC 

adopted the nonlegally binding IAEA Code of Conduct as a basis for (1) 

determining which licensees may need additional protective measures for 

the sealed radiological sources in their possession and (2) defining the 

scope of a national source tracking system. NRC found that the curie 

thresholds for radionuclides in the sources identified by the DOE/NRC 

interagency working group were similar enough to the Code of Conduct

categories to warrant adoption of the IAEA source categorization scheme 

to better align domestic and international efforts to increase the safety and 

security of sealed radiological sources.

NRC and DOE have since engaged in separate efforts to (1) assess the 

vulnerability of facilities that contain sealed radiological sources within 

their jurisdictions, (2) promulgate new security measures, and (3) begin 

systematically tracking some of these sources. According to NRC officials, 

NRC has been working with the Agreement States since January 2002, and 

with licensees since September 2002, using a risk informed approach to 

enhance the regulatory requirements applicable to high-risk radioactive 

material. In June 2003 and January 2004, NRC issued its first set of 

protective measures to large irradiators and device manufacturers and 

distributors, respectively. In January 2004, NRC and the Agreement States 

began to consider the need for additional protective measures for other 

licensees. This process has involved several iterations of vulnerability 

assessments of licensee sites that have devices or use applications 

containing IAEA categories 1 and 2 sources, such as teletherapy, gamma 

knife, well-logging devices, and self-shielded irradiators. On September 6, 

2005, NRC announced that over approximately the next 90 days, affected 

licensees will receive orders from the agency spelling out increased 

controls for certain radioactive materials. Over the same period, individual 

Agreement States will issue their licensees legally binding requirements 

essentially identical to NRC’s orders. Materials covered by these 

15DOE/NRC Interagency Working Group on Radiological Dispersal Devices, Radiological 

Dispersal Devices: An Initial Study to Identify Materials of Greatest Concern and 

Approaches to Their Tracking, Tagging and Disposal (May 2003).
Page 12 GAO-05-967 Security of Unwanted Radiological Sources

requirements will be consistent with the IAEA Code of Conduct. Regarding 

source tracking, in November 2003, NRC, with the assistance of the 

Agreement States, identified and initially surveyed approximately 2,600 

entities licensed to possess IAEA categories 1 and 2 sources. The resulting 

interim inventory will supplement other information NRC intends to use in 

developing a national source tracking system. Regarding DOE efforts, DOE 

officials told us that various department offices have been involved in 

developing, reviewing, and issuing domestic and international guidance 

related to the security of sealed radiological sources. Moreover, DOE has 

established its own source tracking system—that is, the Radioactive 

Source Registry and Tracking System—which, among other things, 

includes the unwanted sealed radiological sources that DOE has recovered 

from licensees. 

In addition to securing and tracking sealed radiological sources, IAEA and 

NRC support the disposal of unwanted sources and other radioactive 

waste. IAEA contends that although waste may be safely stored for 

decades, as long as institutional controls are maintained, progress must be 

made toward permanent disposal. According to the Director General for 

Energy and Transport, European Commission, “the sources at greatest risk 

of being lost from regulatory control are disused (unwanted) sources held 

in local storage at the user’s premises waiting for final disposal or return to 

manufacturer.”16 In response to an international joint convention 

addressing spent nuclear fuel and radioactive waste management,17 IAEA 

set forth the elements of an effective national legal and organizational 

structure that would provide for the safe and secure management of 

radioactive waste by appropriate national authorities. One of the key 

indicators of such a structure is that “the amount of waste in storage 

awaiting disposal should depend only upon operational 

considerations...and should not include a backlog due to an inability 

(technical, financial, organizational, etc.) to reduce the backlog.”18 NRC 

also supports the disposal of low-level radioactive waste but has placed no 

time limits on storage, as long as the radioactive material is safe and 

16IAEA, Proceedings of an international conference on security of radioactive sources, held 

March 10-13, (Vienna, Austria: 2003). 

17A Joint Convention on the Safety of Spent Fuel Management and on the Safety of 

Radioactive Waste Management, signed by Member States of the IAEA, entered into force on 

June 18, 2001.

18IAEA, Radioactive Waste Management: Status and Trends—Issue No. 2 (Vienna, Austria: 

September 2002) p. 16.
Page 13 GAO-05-967 Security of Unwanted Radiological Sources

secure. NRC contends that it is acceptable to allow some licensees to store 

a backlog of sources in instances where a disposal option for this waste is 

not available to them.

In August 2005, the President signed into law the Energy Policy Act of 2005, 

which, among other things, addressed the safe disposal of GTCC waste and 

nuclear facility and materials security. The act requires DOE to prepare 

plans for the continued recovery of sealed radiological sources and to 

report on its efforts to develop a GTCC waste disposal site. Other 

provisions call for NRC to issue regulations establishing a mandatory 

tracking system for radiation sources in the United States and to chair a 

task force on radiation source protection and security. The task force, 

comprised of NRC, DOE and other federal agencies, in consultation with 

other groups, is to evaluate and provide recommendations relating to the 

security of radiation sources in the United States from potential terrorist 

threats, including acts of sabotage or theft or the use of radiation sources in 

a radiological dispersal device. 

DOE Has Increased 

Emphasis on Its Source 

Recovery Project and 

Begun Assessing 

Options for Disposing 

of GTCC Waste

DOE has placed increased emphasis on its source recovery project and has 

begun to assess disposal options for GTCC waste. DOE has realigned its 

source recovery project within NNSA to more effectively respond to both 

domestic and international threats posed by unwanted sealed radiological 

sources. Further, DOE has accelerated its recovery efforts, surpassing an 

earlier source recovery goal, and has made progress in resolving a storage 

space shortage at its facilities that has slowed the recovery of certain 

unwanted sealed radiological sources. Finally, DOE has begun preparing an 

environmental impact statement to assess possible disposal options for 

GTCC waste. However, difficulties in estimating current GTCC waste 

storage and future waste volumes, especially from sealed radiological 

sources, will complicate this effort. Further, DOE has not yet determined 

when a permanent GTCC waste disposal facility will be available.

DOE Transferred 

Responsibility for the 

Source Recovery Project to 

NNSA

To better respond to the security threats posed by unwanted sealed 

radiological sources both within the United States and abroad, in October 

2003, DOE realigned management responsibilities for its source recovery 
Page 14 GAO-05-967 Security of Unwanted Radiological Sources

project from the Office of Environmental Management to NNSA.19 This 

realignment was, in part, a response to a recommendation to the Secretary 

of Energy that we made in our April 2003 report that the priority given to its 

Off-Site Source Recovery Project be commensurate with the threat posed 

by some unwanted sealed radiological sources. Subsequently, NNSA 

established the Nuclear and Radiological Threat Reduction Task Force, 

under the Office of Defense Nuclear Nonproliferation, to unite all of the 

department’s radiological threat reduction efforts. One of the principal 

missions of this task force is to identify; secure; and store, on an interim 

basis, radioactive materials that could be used as a radiological weapon. In 

May 2004, DOE announced the creation of the Global Threat Reduction 

Initiative, which further elevated the importance of the task force and 

DOE’s recovery of sealed radiological sources. This initiative was later 

institutionalized in the Office of Global Radiological Threat Reduction, 

with a domestic component, the U.S. Radiological Threat Reduction 

Program, and an international component, the International Radiological 

Threat Reduction Program. The Off-Site Source Recovery Project was 

subsumed under the U.S. Radiological Threat Reduction Program, but the 

program retained Los Alamos National Laboratory personnel to continue 

the source recovery effort. 

DOE Accelerated Its Efforts 

to Recover Unwanted 

Sealed Radiological Sources

DOE accelerated the recovery of unwanted sealed radiological sources 

beginning in late 2002. As we reported in April 2003, DOE’s ability to meet 

planned recovery activities was largely facilitated by supplemental 

congressional funding and by the urging of NRC to accelerate recovery 

efforts in light of the events of September 11, 2001. In August 2002, the 

Congress provided an additional $10 million to DOE’s Off-Site Source 

Recovery Project to recover 5,000 unwanted sealed radiological sources 

over the following 18 months.20 Between October 1, 2002, and March 31, 

2004, DOE recovered 5,529 of these sources, exceeding its recovery goal 

and more than doubling the number of sources previously recovered since 

1996. As of June 7, 2005, DOE had recovered 10,806 of these sources. 

According to the source recovery project leader, the bulk of the remaining 

19This realignment did not include transferring responsibilities for the long-term storage and 

disposal of the recovered sources.

20H.R. Rep. No. 107-593, at 142 (2002), conference report accompanying Pub. L. No. 107-206, 

Making Supplemental Appropriations for Further Recovery From and Response to 

Terrorist Attacks on the United States for the Fiscal Year Ending September 30, 2002, and 

for Other Purposes.
Page 15 GAO-05-967 Security of Unwanted Radiological Sources

excess and unwanted sealed radiological sources in the United States 

should be recovered in the next 2 years. Table 2 contains a summary of 

DOE-recovered sealed radiological sources, by radionuclide, as of June 7, 

2005.

Table 2: Summary of DOE-Recovered Sealed Radiological Sources, by 

Radionuclide, as of June 7, 2005

Source: DOE source recovery project inventory database.

a

A curie is a measure of the rate of radioactive decay; it is equivalent to the radioactivity of 1 gram of 

radium or 37 billion disintegrations per second.

DOE has maintained its source recovery project efforts through annual and 

supplemental appropriations. In our April 2003 report, we recommended 

that the Secretary of Energy ensure that adequate resources be devoted to 

Radionuclide

Number of

sources

Percentage

of total

sources Curiesa

Percentage

of total

curiesa

Americium-241/Beryllium 5,222 48.33% 11,657.48 7.77%

Plutonium-238 1,907 17.65 7,040.66 4.70

Americium-241 1,900 17.58 464.07 0.31

Americium-241/Berylllium/

Cesium-137 552 5.11 26.48 0.02

Cesium-137Cs 363 3.36 1,621.65 1.08

Plutonium-239Pu/Beryllium 255 2.36 543.42 0.36

Colbalt-60 197 1.82 42,602.21 28.41

Plutonium-238/Beryllium 169 1.56 2,186.87 1.46

Plutonium-239 99 0.92 5.48 0.00

Neptunium-237 25 0.23 0.01 0.00

Americium-241/Cerium 24 0.22 51.00 0.03

Americium-241/Lithium 22 0.20 437.00 0.29

Curium-244 18 0.17 7.51 0.01

Radium-226 17 0.16 0.05 0.00

Plutonium-238/Lithium 16 0.15 255.50 0.17

Strontium-90 10 0.09 82,958.85 55.33

Plutonium-238/Lithium/

Cesium-137 7 0.06 66.10 0.05

Uranium-235 2 0.02 0.00 0.00

Americium-241/Boron 1 0.01 15.00 0.01

Total 10,806 100.00% 149,939.34 100.00%
Page 16 GAO-05-967 Security of Unwanted Radiological Sources

covering the costs of recovering and storing unwanted sealed radiological 

sources as quickly as possible. In a September 2004 congressional hearing, 

the director of DOE’s Office of Global Radiological Threat Reduction 

testified that the department had increased funding for the source recovery 

project and had committed funds for continuing these efforts.21 The 

director stated that the fiscal year 2004 program budget was $1.96 million, 

not including about $3.49 million that was added to the budget to respond 

in part to unexpected requests from NRC to recover sources of security 

concern.22 In fiscal year 2005, the source recovery project budget was 

increased to $5.6 million; for fiscal year 2006, DOE has requested $12.8 

million, in part, to better fund the expanded scope of the U.S. Radiological 

Threat Reduction Program. The source recovery project leader has 

estimated an average recovery cost of $3,000 per source, on the basis of the 

initial 10,000 sources recovered, not including commercial disposal costs 

for certain sources. 

DOE plans to continue recovering unwanted sealed radiological sources, at 

least until a GTCC waste disposal site is available. In our April 2003 report, 

we recommended that the Secretary of Energy develop a plan to ensure the 

continued recovery and storage of unwanted sealed radiological sources 

until a GTCC waste disposal site is available. We reported that DOE used 

several sources of information and made three key assumptions when 

projecting the anticipated need to recover 14,309 sources between fiscal 

years 1999 and 2010. The assumptions were that (1) a permanent disposal 

site for the sources would be available by fiscal year 2007; (2) the Off-Site 

Source Recovery Project would continue to recover sources from certain 

holders of sources during a transition period from fiscal years 2007 through 

2010; and (3) after fiscal year 2010, all unwanted sealed radiological 

sources would be shipped by their owners to a disposal site, and the OffSite Source Recovery Project would cease operations. However, according 

to the manager of DOE’s U.S. Radiological Threat Reduction Program, 

these assumptions are no longer used by the department because the lack 

of a firm date for when a GTCC waste disposal site will be available means 

that DOE cannot determine when it will cease recovering unwanted sealed 

radiological sources from licensees. The Energy Policy Act of 2005 requires 

21Statement of Edward G. McGinnis, Director, Office of Global Radiological Threat 

Reduction, National Nuclear Security Administration, Department of Energy, before the 

United States Senate, Energy and Natural Resources Committee, September 30, 2004.

22According to NRC, funding to support its request represented about $500,000 of the 

additional $3.49 supplemental funding for the source recovery project in fiscal year 2004.
Page 17 GAO-05-967 Security of Unwanted Radiological Sources

DOE to submit a plan to the Congress that ensures the continued recovery 

and storage of unwanted sealed radiological sources that pose a security 

threat until a permanent GTCC waste disposal facility is available. Further, 

this DOE manager told us that source recovery project personnel may still 

be needed to help some licensees to meet the packaging requirements of 

any future GTCC waste disposal facility. 

DOE Has Made Progress in 

Resolving a Storage Space 

Shortage That Has Slowed 

Recovery of Some Sealed 

Radiological Sources

DOE has taken actions to address the storage space shortage that has 

prevented the recovery of certain types of unwanted sealed radiological 

sources. We reported in April 2003 that DOE had inadequate storage 

capacity to meet the higher security needs for recovered sealed 

radiological sources containing plutonium-239, and lacked a means for 

temporarily storing sources containing strontium-90 and cesium-137. We 

recommended, among other things, that the Secretary of Energy take 

immediate action to provide storage space for these sources at a secure 

DOE facility. According to the director of DOE’s Office of Global 

Radiological Threat Reduction, as of September 2004, DOE had developed 

sufficient storage space at the Los Alamos National Laboratory and the 

Nevada Test Site to recover more than 260 plutonium-239 sealed 

radiological sources registered by licensees for collection. According to the 

source recovery project team leader, DOE’s plan has been to recover over 

100 remaining plutonium-239 registered sources, representing 

approximately 60 drums of waste;23 ship them to the Nevada Test Site; and 

then incrementally transfer them to the Los Alamos National Laboratory as 

space is made available from the shipment of the existing stored 

plutonium-239 sources to the Waste Isolation Pilot Plant (WIPP) in New 

Mexico.24 WIPP will only accept sources that are shipped from Los Alamos. 

Implementation of this plan, however, has been delayed pending final 

approvals to ship these sources between locations. 

23As a comparison, according to the source recovery project team leader, the Los Alamos 

National Laboratory is currently storing 21,000 55-gallon drums of DOE- or defense-related 

nuclear waste destined for disposal at WIPP.

24WIPP, operated by DOE and licensed by the Environmental Protection Agency, is an 

underground repository for defense-generated transuranic waste. Transuranic waste refers 

to man-made radioactive wastes that have particles whose atoms are heavier than uranium; 

are alpha particle-emitting, with a half-life longer than 20 years; and have a concentration 

greater than 100 nano-curies per gram of waste. These wastes include radionuclides, such as 

americium-241, plutonium-238, and plutonium-239, that are generated by nuclear weapons 

production and the reprocessing of spent nuclear fuels.
Page 18 GAO-05-967 Security of Unwanted Radiological Sources

Additional progress has been made in addressing the storage issues that 

relate to unwanted strontium-90, cesium-137, and some cobalt-60 sealed 

radiological sources. According to the source recovery project team leader, 

DOE has recovered a strontium-90 radioisotopic thermoelectric generator 

that was owned by the department and used as a remote power supply and 

disposed of the generator at the Nevada Test Site. DOE also has recovered 

six of these devices that were commercially owned and is storing them at 

the Los Alamos National Laboratory, pending approval for disposal as 

waste. Regarding the cesium-137 sealed radiological sources, the source 

recovery project has recycled 5 large cesium-137 irradiators to commercial 

firms. DOE has also contracted to recover the remaining 14 registered 

irradiators by the end of fiscal year 2005. Moreover, the team leader told us 

that the source recovery project plans to collect 221 cobalt-60 sources from 

a university this summer and to dispose of them at the Nevada Test Site as 

DOE-owned nuclear material.

DOE Is Preparing an 

Environmental Impact 

Statement for GTCC Waste 

Disposal Options, but 

Estimating Storage and 

Future Waste Volumes Will 

Be Difficult

DOE has begun to take action to identify a suitable location for the disposal 

of GTCC waste, but producing useful estimates of the current storage and 

future generation of this waste will be difficult. We reported in April 2003 

that DOE had not made progress toward providing for a permanent 

disposal facility for the nation’s GTCC waste, and that it was unlikely to 

provide such a facility by fiscal year 2007 because developing a disposal 

site for this waste was considered a low priority within the department. We 

recommended that the Secretary of Energy initiate a process to develop a 

permanent disposal facility for GTCC waste, including empowering an 

office to take on this responsibility. In September 2004, DOE took a first 

step in this direction by transferring responsibility for assessing disposal 

options for GTCC waste from its Office of Environment, Safety, and Health 

to its Office of Environmental Management. With this authority and the 

heightened need to take action, on May 11, 2005, the Office of 

Environmental Management published an advance notice in the Federal 

Register of its intent to prepare an environmental impact statement (EIS) 

for GTCC waste disposal.25 DOE now anticipates that the actual notice of 

intent to prepare the EIS will be issued in the fall of 2005, followed by 

public meetings to further define the scope of the EIS and to identify 

significant issues to be addressed. The DOE document manager for the EIS 

told us that after the notice of intent is issued, the process of preparing the 

2570 Fed. Reg. 24775 (May 11, 2005).
Page 19 GAO-05-967 Security of Unwanted Radiological Sources

EIS could take 2 years. The Energy Policy Act of 2005 requires that, within 

1 year, DOE report to the Congress on the estimated costs and a proposed 

schedule to complete both the EIS and a record of decision for a permanent 

disposal facility for GTCC waste. Moreover, before DOE makes a final 

decision on the long-term disposal alternative or alternatives to be 

implemented, this act requires DOE to prepare a report to the Congress 

describing all alternatives under consideration, including 

recommendations for ensuring the safe disposal of GTCC waste, and then 

to await action by the Congress. Therefore, it is not possible for DOE to 

determine when a permanent disposal facility will be available for GTCC 

waste. 

In his September 2004 congressional testimony, the director of DOE’s 

Office of Global Radiological Threat Reduction, stated that the EIS for 

GTCC waste disposal will include an analysis of waste inventories, longterm disposition alternatives, and resource requirements—as well as an 

assessment of legislative, regulatory, and licensing requirements. 

According to the director, the broad scope of the EIS should enable DOE to 

consider any new or existing site, facility, and disposal method for GTCC 

waste. Possible locations and disposal options include commercial, DOE, 

or other governmental facilities and private land. The disposal methods 

examined will range from deep geologic disposal to enhanced near-surface 

disposal, depending on the type of GTCC waste. 

In completing the EIS, DOE plans to inventory the GTCC waste in storage 

at licensee and DOE facilities as well as estimate the waste expected to be 

generated in the future. According to the DOE document manager for the 

EIS, the department will obtain information on nuclear utility and DOE 

GTCC waste that is currently in storage and will estimate future volumes 

over the next 30 to 50 years on the basis of a representative sample of some 

nuclear power plants that are being decommissioned, and from existing 

DOE databases. For nonutility licensees, the information on the storage 

and projected generation of GTCC waste will be more speculative. This 

official said that DOE has selected a contractor to update the estimates 

made in a 1994 DOE report that the department now considers outdated.26

DOE asked the contractor to begin with the methodology used in the 1994 

report to estimate current GTCC waste storage and to project future 

26Idaho National Engineering Laboratory, Greater-Than-Class C Low Level Radioactive 

Waste Characterization: Estimated Volumes, Radionuclides and Other Characteristics,

DOE/LLW-114, Revision 1 (Idaho Falls, ID: September 1994).
Page 20 GAO-05-967 Security of Unwanted Radiological Sources

generation of these wastes by nonutility licensees, rather than attempt to 

survey all NRC and Agreement State licensees that might possess these 

radioactive materials. 

Attempting to obtain information on nonutility licensee storage of GTCC 

waste that can be used to estimate future generation of GTCC waste from 

sealed radiological sources will be especially difficult. Of the three types of 

GTCC waste, the second largest volume behind activated metals is from 

sealed radiological sources. Uncertainties surround producing these 

estimates, such as (1) how to determine the quantities of unwanted sealed 

radiological sources in storage and (2) how much waste and what class of 

waste might be generated once these sources are packaged for disposal. 

One estimating problem is that there is currently no standard process by 

which licensees declare their sealed radiological sources as disused 

(unwanted). According to an NRC official, sealed radiological sources 

would not be considered waste, even if they are stored unused by a 

licensee, until the licensee has determined that they are no longer useful. In 

addition, sealed radiological sources that are no longer useful may be 

returned to the source manufacturer or allowed to decrease in radioactivity 

concentration while in storage so that they can be disposed as a lower level 

waste class. Because licensees typically do not declare their disused 

(unwanted) sources as waste until they are packaged and ready for 

shipment to a waste broker or disposal site, it will be difficult for DOE to 

project when this type of waste might need disposal in a GTCC waste 

disposal facility. 

Another uncertainty in estimating the future quantities of GTCC waste is 

that the volume of waste generated by a small sealed radiological source is 

determined by the size of its disposal container and not by the size of the 

source or number of sources in the container. Disused sources are typically 

placed in 30-gallon or 55-gallon disposal drums. The number of sources put 

into one drum and the packing materials used are affected by the 

acceptance criteria of the disposal site. Figure 2 shows a sequence of 

photographs depicting source recovery project personnel removing a 5-

curie, plutonium-239/beryllium source and repackaging it into a 55-gallon 

drum especially designed to meet the acceptance criteria at WIPP. Source 

recovery project personnel told us that these drums cost between $5,000 

and $6,000 each. The sealed radiological source held in pliers in the first 

photograph is clearly a fraction of the size of the 55-gallon disposal drum. 
Page 21 GAO-05-967 Security of Unwanted Radiological Sources

Figure 2: Source Recovery Project Personnel Remove a Sealed Radiological Source and Repackage It into a WIPP-Acceptable 

Disposal Drum

Figures 3 through 5 show photographs that illustrate the scale of sealed 

radiological sources relative to their devices as well as how the sources or 

their devices are packaged into more traditional disposal drums.

Pictured left to right: A sealed source being removed (in pliers) from a shielded storage container at 

a recovery site; the interior of a multifunction container used for transport, storage, and disposal; and 

the process of closing the steel pipe component after the source has been loaded into the 

multifunction container.

Source: GAO.
Page 22 GAO-05-967 Security of Unwanted Radiological Sources

Figure 3: Relative Size of a Sealed Radiological Source and Typical Disposal Drums 

A display of sealed radiological source components: (A) radioisotopes in powder or ceramic pellet 

form within glass vials, (B) solidified radioactive material, (C) metal cells with lid to hold the 

radioactive material, (D) completed sealed radiological sources, and (E) two types of protective 

metal holders. Note the nickel (F) for scale.

Source: GAO.

A

B C

F

D

E
Page 23 GAO-05-967 Security of Unwanted Radiological Sources

Figure 4: A Cross Section of a Nuclear Gauge, and Leveling Gauges Returned to a Manufacturer 

Leveling gauges returned to a manufacturer, each containing a sealed 

radiological source. Most sealed source manufacturers state that these 

types of devices have 15 years of working life.

Source: GAO. Source: GAO.

A cross section of a nuclear gauge for level or density measurement that 

relies on a cesium-137 sealed radiological source, as shown in the middle 

of the gauge (A).

A
Page 24 GAO-05-967 Security of Unwanted Radiological Sources

Figure 5: Interior Views of Two 55-Gallon Disposal Drums, One with a Large Opening for an Entire Disused Device and the Other 

with a Narrow Pipe Opening for Only Sources

Yet another uncertainty in projecting the future volume of GTCC waste 

from sealed radiological sources is that different types of radionuclides can 

comprise the sources used in a device, and, depending on the radionuclide 

used, the age of the source, and how the source is packaged for disposal, 

the device can fall into different classes of waste. For example, as shown in 

table 4 in appendix II, six different radionuclides can be used as the source 

in an industrial radiography device. Further, the sources that can be used in 

this industrial radiography device can produce non-GTCC and GTCC 

waste, depending in part on how much radioactivity remains in the source 

when it is disposed of and how the source is packaged. For example, a 5-

curie, cesium-137 sealed radiological source that is used in a device might 

fall into a GTCC waste class when packaged if little of the source is 

depleted; but once it becomes unwanted and then packaged in a 55-gallon 

disposal drum with nonradioactive filler material, it might fall into the nonGTCC waste class because its radioactivity, as averaged over the entire 

volume of the drum, would be lower. 

Interior view of a 55-gallon disposal drum with a large opening, 

surrounded by concrete, that will hold a disused leveling gauge device 

from which the sealed radiological source could not be safely removed. 

Interior view of a 55-gallon disposal drum with a narrow pipe opening, 

surrounded by concrete, in which sealed radiological sources will be 

placed. 

Source: GAO. Source: GAO.
Page 25 GAO-05-967 Security of Unwanted Radiological Sources

DOE Expanded the 

Scope of Its Source 

Recovery Project to 

Include Non-GTCC 

Waste, Which Could 

Increase Project 

Expenditures 

DOE has expanded its source recovery efforts to include all sealed 

radiological sources that could present a threat, a change that could 

increase project expenditures. DOE’s source recovery project now 

includes, among other activities, the recovery and commercial disposal of 

non-GTCC waste from unwanted sealed radiological sources that pose a 

health, safety, security, or environmental threat. The recovery and 

commercial disposal of more of these types of sealed radiological sources 

from licensees that cannot afford to dispose of them today, in addition to 

the recovery of higher radioactive sources, is likely to increase DOE 

project expenditures. Further, DOE may need to recover even more nonGTCC waste from unwanted sealed radiological sources in the future if 

licensees in many states lose access to the only commercial low-level 

radioactive waste disposal site where they can currently dispose of higher 

radioactive non-GTCC waste (classes B and C waste). This increased 

recovery of non-GTCC waste from sealed radiological sources will place 

greater demands on source recovery project expenditures because of 

impediments to DOE’s recouping recovery costs from licensees that could 

otherwise cover their source disposal costs if there were disposal 

availability. In the absence of access to commercial disposal, DOE 

anticipates the need to indefinitely store the recovered non-GTCC waste 

until a commercial disposal option becomes available. DOE’s current 

policy does not include using DOE sites to permanently dispose of this 

waste because, among other reasons, it does not want to undermine the 

authority the Congress gave to the states to provide disposal availability for 

non-GTCC waste.

DOE Has Recovered and 

Commercially Disposed of 

Some Non-GTCC Waste 

The expanded scope of the source recovery project now includes, among 

other activities, the collection and commercial disposal of non-GTCC waste 

from unwanted sealed radiological sources that pose a health, safety, 

security, or environmental threat.27 Responsibility for the safe management 

and disposal of these radioactive materials is normally held by those 

entities that NRC or the Agreement States license to possess and use these 

materials. However, in some cases, licensees are unable to (1) ensure the 

safe and secure use of these materials or (2) cover the disposal costs of 

their unwanted sealed radiological sources. For example, according to the 

27The other activities of the source recovery project include recovering from other countries 

sealed radiological sources that were previously owned by the U.S. government, 

cooperating with IAEA, and working with the Department of Homeland Security.
Page 26 GAO-05-967 Security of Unwanted Radiological Sources

source recovery project leader, at the request of NRC, DOE commercially 

disposed of its first significant quantities of non-GTCC waste during fiscal 

year 2004. Source recovery project personnel collected 443 unwanted 

sealed radiological sources (containing cesium-137, cobalt-60, or radium226) from a bankrupt firm in Pennsylvania and commercially disposed of 

most of them at the Barnwell, South Carolina, disposal site. In commenting 

on a draft of this report, DOE provided examples of other non-GTCC waste 

from sealed radiological sources that it had recovered. 

Under the expanded scope of the source recovery project, DOE has 

developed a priority scheme for deciding which sources to recover and 

when to do so. According to the director of DOE’s Office of Global 

Radiological Threat Reduction, DOE has been working with the 

Department of Homeland Security and other agencies, in addition to NRC, 

to determine the sources that should receive the highest priority for 

recovery, including those that when disposed of would not be considered 

GTCC waste. In addition, the manager of DOE’s U.S. Radiological Threat 

Reduction Program told us that DOE and NRC are also in the process of 

revising the 1999 memorandum of understanding that defined the 

responsibilities of each agency with respect to the problem of unwanted 

and uncontrolled sealed radiological sources to better reflect current DOE 

recovery practices. The source recovery project leader provided us with an 

initial priority ranking scheme for recovering sources that is used by DOE, 

as well as some other factors that DOE considers. The initial ranking 

involves combining three factors into an overall risk ranking for each 

licensee site that contains sealed radiological sources. These factors 

include the level of security over the source at a licensee site, the total 

quantity of radioactive material present, and the quantity of radioactive 

material in any single sealed radiological source to a licensee site. Other 

factors that DOE considers when prioritizing sources at recover include the 

opportunity of recovering additional unwanted sealed radiological sources 

that source recovery personnel may discover during their visit at a licensee 

site. For example, the source recovery project leader told us that if team 

members come across vulnerable sealed radiological sources of lesser 

radioactivity at a location where they are recovering higher radioactive 

sources, they will collect them as well. 
Page 27 GAO-05-967 Security of Unwanted Radiological Sources

Recovery of More NonGTCC Waste from Sealed 

Radiological Sources Could 

Increase Project 

Expenditures Because DOE 

Cannot Recoup Recovery 

Costs

DOE has already incurred additional expenses to recover and 

commercially dispose of non-GTCC waste from unwanted sealed 

radiological sources. It cost DOE approximately $581,000 to recover 

hundreds of these sources that had accumulated at a bankrupt firm in 

Pennsylvania and to commercially dispose of them. The Barnwell disposal 

site received 15 of the 16, 55-gallon and 30-gallon drums of this non-GTCC 

waste and charged DOE a $1,650 per-cubic-foot disposal fee. For example, 

the disposal fee and container cost for just 1, 55-gallon disposal drum 

holding 130 of the recovered cesium-137 sealed radiological sources cost 

DOE about $21,000, not including labor, transport, and other costs. 

Additional DOE recovery of non-GTCC waste from licensees that currently 

need to store their sources and other waste because they do not want to or 

cannot pay these high disposal fees may be necessary in the future. 

According to the deputy director of DOE’s Office of Global Radiological 

Threat Reduction, because of the cost involved, encouraging those 

licensees that have sealed radiological sources to dispose of them properly 

has proven difficult, particularly with entities that only have a few sources. 

NRC can impose fines as high as three times the cost of commercial 

disposal on a licensee that fails to properly dispose of radioactive 

material.28 However, a senior NRC official has publicly acknowledged the 

difficulty that licensees with only a few unwanted sources have in finding a 

cost-effective means for disposing of them. 

DOE is currently impeded from recouping more of its recovery and storage 

costs for GTCC waste as well as any non-GTCC wastes that it may need to 

recover. Regarding GTCC waste, since DOE issued its 1987 report on how it 

planned to address its responsibilities under the Low-Level Radioactive 

Waste Policy Act of 1980, as amended, no specific action has been taken to 

identify a different method of funding the source recovery project, other 

than through the appropriations process. According to the manager of 

DOE’s U.S. Radiological Threat Reduction Program, DOE has been unable 

to establish a standard fee for recovering unwanted sealed radiological 

sources from licensees because existing cost recovery mechanisms require 

the department to know both the number of years that these sources will 

be stored and the cost of their disposal before setting a fee, which is not 

currently possible. Regarding non-GTCC waste, the sources recovered to 

date were primarily from a commercial firm that had gone bankrupt and 

28NRC policy establishes base civil penalties for loss, abandonment, or improper transfer or 

disposal of sealed radiological sources and devices that, according to NRC, have been 

imposed on many occasions.
Page 28 GAO-05-967 Security of Unwanted Radiological Sources

did not have the necessary funds to cover the cost of disposing of its 

sources. DOE had to cover the recovery and commercial disposal costs 

because there was no other source of funding. One of the reporting 

requirements for the task force on radiation source protection and security, 

required under the Energy Policy Act of 2005, is to provide 

recommendations for appropriate regulatory and legislative changes for 

the establishment of, or modification to, a national system (including user 

fees and other methods) to provide for the proper disposal of sealed 

radiological sources under the act.

DOE May Need to Recover 

and Dispose of More NonGTCC Waste If Licensees 

Have No Disposal Option, 

Further Increasing 

Demands on Project 

Expenditures

In the future, DOE may have to recover more non-GTCC waste from sealed 

radiological sources if licensees that are forced to store their unwanted 

sources because they have no access to a disposal site. As we reported in 

June 2004, if South Carolina follows through with plans to restrict access to 

the Barnwell disposal site to only the three member states of the Atlantic 

Compact by mid-2008, and if no disposal alternative for the more highly 

radioactive non-GTCC waste (classes B and C waste) is developed, 

licensees in 36 states that are presently allowed to use this site will need to 

store more of their unwanted radioactive materials. Although NRC does 

not place time limits on the storage of radioactive materials as long as they 

are safe and secure, greater quantities and longer periods of storage, 

particularly of unwanted sealed radiological sources, will likely increase 

safety and security risks. In January 2002, NRC sent a letter to DOE 

requesting that the source recovery project take actions to recover 

registered unwanted sealed radiological sources because the possession 

and storage of these sources with no GTCC waste disposal outlet 

represented a potential health and safety threat. Regarding non-GTCC 

waste from unwanted sealed radiological sources, the manager of DOE’s 

U.S. Radiological Threat Reduction Program told us that DOE will likely 

need to increase the recovery of these sources if licensees have no 

commercial disposal option for this waste. Domestic and international 

experts contend that the lack of disposal availability for unwanted sealed 

radiological sources can increase their risk of abandonment, 

misplacement, and theft. For example, the Health Physics Society29 stated 

29The Health Physics Society is a nonprofit, scientific professional organization whose 

mission is to promote the practice of radiation safety. The society has approximately 6,000 

scientists, physicians, engineers, lawyers, and other professionals representing academia, 

industry, government, national laboratories, the Department of Defense, and other 

organizations.
Page 29 GAO-05-967 Security of Unwanted Radiological Sources

that the lack of a GTCC and non-GTCC waste disposal option for unwanted 

sealed radiological sources that pose security and public health concerns 

will continue to increase the number of orphan sources. Further, IAEA has 

reported that disused (unwanted) sources represent the largest pool of 

vulnerable and potential orphan sources.30 If DOE were to begin recovering 

more non-GTCC waste from unwanted sealed radiological sources, even 

greater demands will be placed on DOE recovery project resources if DOE 

cannot recoup some of its recovery costs from licensees. While DOE is 

justified in covering the recovery and commercially disposal cost of the 

non-GTCC waste it has collected from licensees that could not afford to 

dispose of it themselves, the department may be able to recoup some of its 

costs in the future from licensees that could afford the cost of disposal if it 

were commercially available. 

It is difficult to estimate the budgetary impact on DOE if there were a need 

to increase the recovery of unwanted sealed radiological sources from 

licensees that have no access to a commercial disposal site for their higher 

radioactive non-GTCC waste. One reason for this situation is the lack of 

information on the number of sources in storage that might need DOE 

recovery. As we reported August 2003, there is no national database on the 

quantities of sealed radiological sources in storage. Moreover, there is no 

national database that tracks the storage of any low-level radioactive 

waste. Given the lack of national data on how much waste is generated 

annually, the disposal data from low-level radioactive waste disposal 

operators can only provide an indication of the quantity of disused or 

unwanted sealed radiological sources and other waste that might need 

storage each year in the absence of disposal availability. Nevertheless, we 

found that between 2001 and 2004, the Barnwell disposal site disposed of, 

on average, 31,150 cubic feet of the higher radioactive non-GTCC waste 

(classes B and C waste), of which about 588 cubic feet, or about 2 percent 

of the total, was derived from disused sealed radiological sources.31

Approximately one-half of the sealed radiological source waste (about 56 

percent) came from private industry, followed by government agencies 

(about 25 percent), colleges and universities (about 11 percent), and 

30IAEA, Strengthening Control Over Radioactive Sources in Authorized Use and 

Regaining Control Over Orphan Sources: National Strategies, IAEA-TECDOC-1388 

(Vienna, Austria: February 2004) p. 54.

31Between 2001 and 2004, the other low-level radioactive waste disposal site in Washington 

only received an average of 155 cubic feet of classes B and C waste comprised of sealed 

radiological sources. 
Page 30 GAO-05-967 Security of Unwanted Radiological Sources

medical waste (about 4 percent). If DOE recovered, took title of, and 

commercially disposed of all non-GTCC waste from sealed radiological 

sources that are sent to the Barnwell disposal site annually, it might cost 

DOE approximately $1 million a year just to cover the disposal cost at the 

current $1,700 cubic foot disposal fee rate. However, until DOE has better 

information on the number of sources that may need to be recovered and 

future disposal costs, including recovery, packaging, transport, and other 

costs, it will be difficult to accurately estimate future costs of recovering 

non-GTCC waste. 

Lack of Commercial 

Disposal Availability Could 

Heighten Interest in Using 

DOE Sites for Disposal

If licensees lose access to commercial disposal sites for their higher 

radioactive non-GTCC waste in the future, DOE will likely have to recover 

more of this waste from unwanted sealed radiological sources, which could 

heighten interest in using DOE sites for disposal of these wastes. The 

manager of DOE’s U.S. Radiological Threat Reduction Program told us that 

although DOE is not legally prohibited from permanently disposing of, at 

DOE sites, the recovered non-GTCC waste for which it has taken title, it 

would not want to do so. This DOE manager said that on the basis of 

current policy, DOE would indefinitely store any recovered non-GTCC 

waste from unwanted sealed radiological sources at its sites until 

commercial disposal is available or DOE receives other congressional 

guidance. The DOE manager provided three reasons to justify this current 

policy. First, DOE does not want to undermine the responsibility given by 

the Congress to the states to provide disposal availability for non-GTCC 

waste under the Low-Level Radioactive Waste Policy Act of 1980, as 

amended. Second, DOE is not allowed to compete with commercial waste 

companies for the disposal of non-GTCC waste. Finally, DOE does not want 

to dispose of the relatively small quantity of recovered non-GTCC waste at 

its sites because this might set a precedent for disposing of all non-GTCC 

waste that does not have a commercial disposal pathway. However, in lieu 

of storing this non-GTCC waste, this DOE manager suggested that DOE 

could, under emergency access provisions, approach the regulatory bodies 

that have jurisdiction over commercial disposal sites to obtain disposal 

access. Despite DOE’s current policy regarding what it would do in the 

future with recovered non-GTCC waste if there were no commercial 

disposal availability, there have been calls to consider using DOE sites for 

the disposal of this waste. Our June 2004 report32 discussed some issues 

32GAO-04-604.
Page 31 GAO-05-967 Security of Unwanted Radiological Sources

that would need to be resolved to use DOE sites for this waste, including 

the feasibility of DOE’s accepting all non-GTCC waste, the responsibility 

for paying for the disposal of this waste, and the licensing and regulatory 

responsibilities covering its disposal.

DOE Lacks 

Information to Better 

Identify Unwanted 

Sealed Radiological 

Sources That May 

Need Recovery 

DOE lacks information that would assist in its efforts to identify and 

recover unwanted sealed radiological sources that pose a safety or security 

risk. Although DOE maintains an inventory of recovered sealed 

radiological sources and sources registered for future recovery, neither 

DOE nor any other government agency has centrally tracked the number of 

sources in the United States or the number of unwanted sources in storage 

at licensee sites across the country. Under the current regulatory structure, 

NRC and Agreement states only know the authorized uses and maximum 

quantities allowed for each licensee, not what they actually possess. As a 

result, DOE has no means of determining the actual number of sealed 

radiological sources that may require recovery in the future. NRC is 

currently developing a national source tracking system to, among other 

things, identify the possession and movement of some high-risk sealed 

radiological sources. However, as presently designed, this tracking system 

lacks information that DOE might find useful in planning and budgeting for 

the recovery of unwanted sealed radiological sources and their eventual 

disposal. 

DOE Has Information on 

Sealed Radiological Sources 

Already Recovered and 

Limited Information on 

Those to Be Recovered 

The source recovery project maintains its own inventory of sealed 

radiological sources that have been recovered and are in storage, and those 

that licensees or NRC have asked DOE to recover. According to the source 

recovery project team leader, the accuracy of the information on a sealed 

radiological source in this inventory improves from when a licensee 

initially registers the source; to when source recovery personnel have 

follow-up conversations with the licensee to clarify the recovery request 

for the source; to when the source recovery project team actually visits the 

site to physically inspect the source, record its serial number, and package 

it for disposal. The source recovery project team leader told us that the 

information on sources initially registered is less accurate because the 

licensee may not know anything about their source, or a licensee might 

inadvertently provide incorrect information about the source, such as its 

radionuclide and radioactivity concentration. Once recovered, the 

information in the source recovery project inventory includes the type of 

radionuclide, serial number, size, radioactivity concentration, and method 
Page 32 GAO-05-967 Security of Unwanted Radiological Sources

of packaging for storage or disposal. The source recovery project team 

leader told us that this inventory is designed to assist in administrative 

planning, scheduling and prioritizing recoveries, tracking shipments, and 

documenting storage or disposal locations. 

Information on the recovered sealed radiological sources in DOE’s 

possession is then integrated into DOE’s Radiological Source Registry and 

Tracking System. This departmentwide inventory system was established 

in November 2003, in response to a recommendation of the DOE/NRC 

Interagency Working Group on Radiological Dispersal Devices. The 

tracking system is managed by DOE’s Office of Plutonium, Uranium, and 

Special Materials Inventory and maintained at Sandia National 

Laboratories. DOE designed its system to help (1) monitor the safety and 

security of all DOE-owned sealed radiological sources that meet a certain 

threshold size and radioactivity concentration and (2) provide information 

on the potential threat they pose. In addition to descriptive information on 

the type of sealed radioactive source and its location within the DOE 

complex, this tracking system also records data on the source’s status—

such as whether the source is in active use; is inaccessible and, thus, not 

being used; is in storage for potential future use; or is packaged and 

awaiting final disposal. 

DOE Cannot Determine 

How Many Unwanted 

Sealed Sources May Need 

Recovery

Because neither DOE nor any other government agency has centrally 

tracked the number of sealed radiological sources in the United States at 

any given time or the number of unwanted sources held by NRC and 

Agreement States licensees, DOE has few available means of estimating the 

quantities of sources that may need recovery in the future. Under the 

current regulatory structure, NRC and the Agreement States only have 

information on the authorized uses and maximum quantities of radioactive 

materials licensees are allowed to possess, although each licensee is 

responsible for maintaining inventories of its individual sources. Further, 

the source recovery project inventory contains only information that 

licensees have voluntarily provided to DOE on their unwanted sealed 

radiological sources and more limited voluntary registration of sources that 

may require recovery in the future. The information on sealed radiological 

sources that NRC provides to DOE for scheduling recovery only captures 

those sources that NRC or Agreement States are aware of that need 

recovery and does not include sources that licensees may possess that are 

unwanted. Consequently, neither of these methods for obtaining 

information provides the kind of data that DOE can use to estimate future 

quantities of sealed radiological sources that may need recovery. According 
Page 33 GAO-05-967 Security of Unwanted Radiological Sources

to the manager of DOE’s U.S. Radiological Threat Reduction Program, 

because the source recovery project has no information on the number of 

sources in current use or in storage, DOE is limited in its ability to provide 

useful estimates of the quantities of sealed radiological sources that DOE 

might need to recover in the future.

The Proposed National 

Source Tracking System Is 

Not Designed to Collect 

Some Information That 

Could Be Useful to DOE

NRC plans to develop a national source tracking system that will register 

certain sealed radiological sources possessed by licensees and/or DOE. In 

November 2003, NRC, in cooperation with the Agreement States, contacted 

2,600 entities licensed to possess IAEA categories 1 and 2 sources in an 

effort to capture for the first time national data on the actual type, 

quantities, and current ownership of these sources. Over 99 percent of 

these licensees voluntarily reported information back to NRC, but only 

about one-half of them reported that they possessed these sources. NRC 

has already conducted a follow-up survey of a portion of these licensees, 

and other surveys are planned leading up to an implementation of the 

national source tracking system in 2007. Although licensees are requested 

to volunteer information for these interim surveys, NRC issued a proposed 

rule in July 200533 that would, among other things, require licensees to 

provide an inventory of their sealed radiological sources; annually verify 

and reconcile their actual inventory with the information registered in the 

system; and report certain transactions, such as the date of manufacture, 

transfer, or disposal of their sealed radiological sources. The Energy Policy 

Act of 2005 requires that NRC issue regulations, within 1 year, establishing 

this mandatory tracking system that shall be coordinated with systems 

established by the Department of Transportation to track the shipment of 

radiation sources. Such a tracking system must, among other things, 

provide for the reporting of required information through a secure Internet 

connection.

As presently designed, NRC’s national source tracking system will 

inventory and monitor primarily IAEA categories 1 and 2 sources—the 

minimum required under the 2004 IAEA Code of Conduct—despite support 

from IAEA and DOE for tracking additional source categories and other 

3370 Fed. Reg. 43646 (July 28, 2005).
Page 34 GAO-05-967 Security of Unwanted Radiological Sources

information.34 In its July 2003 technical document detailing the 

methodology behind the IAEA source categorization scheme, IAEA 

suggested that member states consider the combined radioactivity of 

aggregated sealed radiological sources in one location for the purpose of 

categorizing these sources on the basis of their potential to cause harm to 

human health.35 Using this methodology, the accumulation of enough 

individual IAEA category 3 sources in close proximity to one another 

would yield concentrations of radioactive material equivalent to a single 

IAEA category 2 source. For example, storing 15 well-logging devices in 

close proximity (each well-logging device typically contains a 2-curie, 

cesium-137 source, which is an IAEA category 3 source) would be 

equivalent to having a 30-curie, cesium-137 source in this location, which is 

an IAEA category 2 source. 

Almost all of the unwanted sealed radiological sources recovered by DOE 

would fall into categories below IAEA categories 1 and 2 and, therefore, 

would not have been registered in the national source tracking system as 

presently designed. According to the manager of DOE’s U.S. Radiological 

Threat Reduction Program, over 90 percent of the sites where DOE has 

recovered sealed radiological sources had quantities of lesser radioactive 

sources that when aggregated were equivalent to an individual IAEA 

category 2 source and, thus, posed enough of a safety and security risk to 

warrant their recovery. This recovery has been justified despite the fact 

that the total curie level of all the recovered IAEA category 3 sources was 

only about 15 percent of the curie level of the relatively few recovered 

categories 1 and 2 sources, and without regard to whether the sources 

might or might not have been located in close proximity at each of the 

licensee sites. In a 2004 technical document, IAEA suggested that it would 

be beneficial from both a safety and security viewpoint for all disused or 

unwanted sealed radiological sources to be identified and to undergo 

proper disposition.36 According to IAEA, the quality of a country’s national 

registry of radioactive sources will be a prime indicator of the probability 

of there being vulnerable and orphan sources. History has shown that many 

34NRC has added seven radionuclides not recommended for tracking by the IAEA Code of 

Conduct, including actinium-227, polonium-210, plutonium-236, plutonium-239, plutonium240, thorium-228, and thorium-239. Although these radionuclides are not prevalently used by 

licensees, they are used at DOE facilities.

35IAEA, Categorization of Radioactive Sources, p. 9.

36IAEA, Strengthening Control Over Radioactive Sources, pp. 39, 54.
Page 35 GAO-05-967 Security of Unwanted Radiological Sources

accidents involving orphan sources come about because sources that are 

no longer in use are eventually forgotten, with subsequent loss of control 

years later. Table 3 shows a breakdown of the sealed radiological sources 

that DOE has recovered, by their IAEA source category, as of June 7, 2005. 

As shown in the table, about 98.5 percent of these sources fall below 

category 2 and, therefore, would not have been tracked in the proposed 

national source tracking system. 

Table 3: DOE-Recovered Sealed Radiological Sources, by Their IAEA Source 

Category, as of June 7, 2005

Source: DOE source recovery project inventory database.

a

A curie is a measure of the rate of radioactive decay; it is equivalent to the radioactivity of 1 gram of 

radium or 37 billion disintegrations per second.

b

Uncategorized sources contain radionuclides that are not covered by an IAEA source category. 

In the proposed rule to implement a national source tracking system, NRC 

states that it does not plan to include IAEA category 3 sources in the 

registry at this time, but that it may consider doing so in the future because 

licensees possessing a large quantity of IAEA category 3 sources could 

present a security concern. Although NRC contends that reliable tracking 

of the accumulation of IAEA category 3 sources will be difficult and might 

pose a potential burden on licensees, NRC is seeking comments on the 

inclusion of these sources in its tracking system. NRC stated in its notice of 

intent that one way to address the accumulation of sources of concern 

would be to lower the threshold for source tracking to include all IAEA 

category 3 sources, since a source level tracking system cannot include 

aggregation of sources because the sources may move in and out of the 

tracking system with the change of ownership. However, in commenting on 

a draft of this report, NRC stated that in lieu of the inclusion of category 3 

sources in the proposed national source tracking system at this time, its 

new security orders for licensees possessing IAEA categories 1 and 2 

IAEA source 

category

Number of

sources

Percentage of

total sources Curiesa

Percentage of

total curiesa

Category 1 37 0.34% 78,984.07 52.68%

Category 2 129 1.19 50,181.55 33.47

Category 3 4,941 45.73 19,540.26 13.03

Categories 4 and 5 5,672 52.49 1,233.43 0.82

Uncategorizedb 27 0.25 0.01 0.00

Total 10,806 100.00% 149,939.32 100.00%
Page 36 GAO-05-967 Security of Unwanted Radiological Sources

sources do, where appropriate, address aggregation of any sources below 

these two categories, such that the net result could reach the category 2 

threshold in a given physical location. Nevertheless, it does not appear that 

these new security orders would apply to licensees that do not possess 

IAEA categories 1 and 2 sources but still have large accumulations of IAEA 

category 3 or lesser source categories.

The national source tracking system, as designed, also would not collect 

other information that DOE might find useful in budgeting and planning for 

source recovery and future disposal needs for GTCC waste. Recent IAEA 

technical guidance states that it is important to capture information on the 

frequency of use of the source in a national registry of sealed radiological 

sources—for example, whether the source is actually being used or 

whether it is being stored securely.37 DOE already inventories such 

information on sources in its possession in its Radioactive Source Registry 

and Tracking System. DOE initially requested that NRC collect information 

on licensees’ disposal plans in its interim survey, including whether the 

licensees were planning to have DOE recover their sources. NRC included 

this question in its first survey of licensees but has decided to drop it in 

subsequent surveys and in the design of the tracking system, because of the 

low response rate to this question and because its security regulations 

currently do not require licensees to report this information. However, NRC 

is contemplating adding a feature to the design of its anticipated national 

source tracking system that would capture information on the long-term 

storage of some sealed radiological sources, although it would be voluntary 

for licensees to provide this information. 

The Energy Policy Act of 2005 requires NRC to chair an interagency task 

force on radiation source protection and security. Within 1 year of its 

creation, the task is to prepare a report to the Congress and the President 

providing recommendations for a list of additional radiation sources that 

should be required to be secured as well as any necessary modifications to 

the national source tracking system. In addition, the task force is also 

charged with making recommendations in this report regarding the 

creation of, or modification to, procedures for improving, among other 

things, the security of stored sources, including periodic audits or 

investigations by NRC to ensure that these sources are properly secured 

and can be fully accounted for.

37IAEA, Strengthening Control Over Radioactive Sources, p. 55.
Page 37 GAO-05-967 Security of Unwanted Radiological Sources

Conclusions DOE and NRC have important roles and responsibilities in ensuring the 

safety and security of radiological sealed sources. The recently enacted 

Energy Policy Act of 2005, among other things, adds new requirements for 

both agencies, including the creation of a task force on radiation source 

protection and security, chaired by NRC, and continued recovery by DOE 

of unwanted sources until it provides a disposal site for GTCC waste. The 

responsibilities for DOE may expand further if licensees in most states lose 

access to the only disposal site for their higher radioactive non-GTCC 

waste by mid-2008. Specifically: 

• Loss of access would increase the quantities of non-GTCC waste in 

storage that could necessitate more recovery of this waste by DOE. 

This, in turn, might lead to increased costs for DOE’s source recovery 

efforts. However, how much additional funding will be necessary for 

this effort would be difficult to ascertain for several reasons, including 

uncertainties regarding the quantity of non-GTCC waste that might need 

collection. 

• These increased recovery and disposal costs will be incurred by DOE 

unless other mechanisms are adopted to recoup these costs, especially 

from those licensees that would be able to cover them if commercial 

disposal were available. 

• The increasing quantities of non-GTCC waste that will not have a 

commercial disposal pathway could heighten interest in using DOE sites 

for the disposal of this waste. 

• The lack of information to track the number and status of sealed 

radiological sources that may require recovery and disposal in the 

future, limits DOE’s ability to effectively plan and budget for its recovery 

and disposal efforts and to monitor the performance of its source 

recovery project. 

Recommendations for 

Executive Action

We recommend that the Secretary of Energy and the Chairman of the 

Nuclear Regulatory Commission, in collaboration with the Task Force on 

Radiation Source Protection and Security, evaluate and report on 

• the cost implications of a potential expansion of DOE’s recovery and 

disposal of non-GTCC waste from sealed radiological sources,
Page 38 GAO-05-967 Security of Unwanted Radiological Sources

• options for DOE to recoup these costs from licensees that may have no 

commercial waste disposal options,

• the feasibility of disposing of this waste at DOE sites, and

• how a national source tracking system can be designed and 

implemented to improve DOE’s ability to identify and track sealed 

radiological sources that may need DOE recovery and disposal. 

Agency Comments and 

Our Evaluation

We provided a draft of this report to DOE and NRC for their review and 

comment. DOE’s written comments are reproduced in appendix III. DOE 

stated that it generally supports the recommendations contained in this 

report. More specifically, DOE commented that we had correctly reported 

the department’s position with respect to recouping recovery and disposal 

costs; however, the department expressed some concern that charging fees 

or recouping costs from licensees may inhibit them from registering 

sources, leaving these excess sources at risk. We acknowledge in the report 

that DOE should cover the recovery, storage, and disposal costs of 

unwanted sealed radiological sources that were previously owned by DOE. 

We also acknowledge the need for DOE to cover these costs in cases where 

sources posing a health, safety, security, or environmental threat are 

recovered from licensees that do not have the financial means to ensure 

their proper disposal. Nevertheless, given the possibility that, in most 

states, there may not be a commercial disposal option available to 

licensees for their higher radioactive non-GTCC waste after mid-2008, we 

continue to believe that DOE and NRC should evaluate approaches to 

recoup recovery and disposal costs from licensees that could otherwise 

afford to cover these costs if a commercial disposal option were available. 

DOE also stated that, in addition to the non-GTCC sealed source waste that 

we stated it recovered and disposed, it had also recovered other sources 

that fall into this waste class. We added a reference to these other sources 

in the report. Regarding using DOE sites for non-GTCC waste disposal, the 

department commented that we appropriately noted its current policy and 

statutory responsibilities that prohibit the use of department facilities for 

this purpose. DOE stated that it would continue to identify potential 

commercial treatments or disposal options for any additional non-GTCC 

waste that is recovered. Finally, DOE concurred with our assessment that 

the proposed national source tracking system should be improved to assist 

the department in identifying and recovering unwanted sources from 

outside the department that pose a potential safety and security risk. DOE 

stated that its Office of Security is working with other elements of the 
Page 39 GAO-05-967 Security of Unwanted Radiological Sources

department and NRC in developing requirements to ensure that these 

unwanted sources are adequately tracked.

NRC also provided written comments to a draft of this report, which are 

reproduced in appendix IV. NRC stated that overall our report was well 

written and balanced. While NRC did not specifically agree or disagree with 

our four recommendations, its letter raised seven issues regarding the 

proposed national source tracking system. 

1. NRC stated that its tracking system would provide some information 

useful to DOE. We agree that the national source tracking system might 

provide some information useful to DOE in its recovery of IAEA 

categories 1 and 2 sources. However, since we found that only 1.5 

percent of the sources recovered by DOE as of June 7, 2005, were in 

these two categories, it appears that the national source tracking 

system would yield little, if any, practical benefits to DOE.

2. NRC stated that requiring the reporting of certain information that our 

report asserts DOE would find useful, such as frequency of source use, 

could be extremely burdensome on licensees and NRC and would yield 

little, if any, practical benefits. NRC provided no support for this 

contention or for why it cannot overcome these burdens as it has done 

in justifying the reporting requirements proposed for licensees 

possessing IAEA categories 1 and 2 sources. In addition, NRC stated in 

its notice of proposed rulemaking for the national source tracking 

system that most licensees already have systems in which information 

on sources is maintained, and that NRC’s tracking system is designed to 

ease the reporting burden for these licensees. As to the comment on the 

practical benefit of tracking the use of high-risk radioactive materials, 

our report notes that the most vulnerable sources to abandonment, 

misplacement, and theft are those that are unwanted and in storage. 

Therefore, it seems reasonable to attempt to collect some information 

on frequency of source use, particularly if the storage of sources were 

to increase in the future in the absence of a commercial disposal option 

for the higher radioactive non-GTCC waste. 

3. NRC commented that our report did not accurately characterize some 

issues involving IAEA category 3 sources, mainly regarding our claim 

that IAEA-TECDOC-1388 suggested that category 3 sources be tracked. 

NRC claimed that the IAEA document did not make this suggestion and 

provided some passages from the document to support its position. We 

believe that NRC’s comments in this regard reflect a narrow view of the 
Page 40 GAO-05-967 Security of Unwanted Radiological Sources

guidance provided by IAEA. For example, in IAEA’s discussion of 

disused (unwanted) sources in this technical document, it clearly 

suggests a need to identify these sources and to gather information on 

their frequency of use.

“Disused sources represent the largest pool of vulnerable and potential orphan sources. 

History has shown that many accidents involving orphan sources come about because 

sources that are no longer in use are eventually forgotten, with subsequent loss of control 

years later. To this end, it is beneficial from both a safety and security viewpoint for all 

disused sources to be identified [emphasis added] and to undergo proper disposition.... 

Licensees are discouraged from proper disposal of disused sources by the cost involved, by 

the bureaucracy of doing so, or by the lack of an available disposal option.... It is clear that 

information needs to be gathered by those developing a national strategy regarding the 

status of at least all [emphasis added] Category 1, 2 and 3 sources on the licensee’s 

inventory or national registry so that appropriate decisions can be made regarding them. 

Generally, this will involve asking the licensee or owner of the source about its frequency of 

use [emphasis added].”

4. In support of its decision not to track IAEA category 3 sources at this 

time, NRC drew attention to its other regulatory efforts, especially its 

new security orders for some licensees that possess IAEA categories 1 

and 2 sources. NRC stated that, where appropriate, these security 

orders address aggregation of any sources (IAEA category 3 sources 

and below) such that the net result could reach the category 2 source 

threshold in a given physical location. Despite these security orders, 

NRC’s source tracking system would not include IAEA category 3 

sources and below. However, NRC stated in its notice of proposed 

rulemaking for the national source tracking system, that it is seeking 

comments on the inclusion of IAEA category 3 sources in the registry 

because licensees possessing large quantities of these sources could 

present a security concern. 

5. NRC pointed out that, as we reported, the actions it is taking to track 

IAEA categories 1 and 2 sources are consistent with the IAEA Code of 

Conduct and the Energy Policy Act of 2005. However, NRC failed to 

mention, as we do in our report, that this legislation also directs NRC to 

chair an interagency task force to provide a report, within 1 year, to the 

Congress and the President with recommendations for, among other 

things, additional radiation sources that should be required to be 

secured as well as any modifications necessary to the national source 

tracking system. We believe that our report provides ample support for 

areas where NRC, in collaboration with DOE and other federal 

agencies, might consider modifying the design of the national source 
Page 41 GAO-05-967 Security of Unwanted Radiological Sources

tracking system to better assist DOE in planning and budgeting for the 

recovery and disposal of unwanted sealed radiological sources. 

6. NRC commented that it does not matter that almost all of the sources 

that DOE has recovered are below IAEA categories 1 and 2 sources 

because, according to NRC, the greatest risk from a source is its 

radioactivity level. The radioactivity of an individual source is clearly 

one measure of its potential safety and security risk. However, as our 

report notes, DOE’s recovery efforts, often at the request of NRC, are 

not solely dictated by the radioactivity of an individual source, but 

more broadly the health, safety, security, or environmental threat posed 

by the aggregated radioactivity of many unwanted sources that are 

typically in storage at licensee sites around the country. Our report also 

notes that unwanted sources in storage tend to be the most vulnerable 

to abandonment, misplacement, and theft despite requirements that 

licensees keep track of the radioactive materials they possess. Some of 

the lesser radioactive sources are frequently found by DOE to be kept 

in quantities where their aggregated radioactivity would be equivalent 

to an IAEA category 2 source that would present a security concern. 

These lesser radioactive sources also may be more susceptible to 

inadvertent loss, which has already led in some cases to radiation 

exposure, high decontamination costs, and public panic. IAEA 

acknowledged in its Code of Conduct that its categorization of high-risk 

radiological sources is based on health effects and does not fully take 

into account the range of impacts that could result from accidents or 

malicious acts involving radioactive sources.

7. NRC stressed in its comments that DOE, through its representatives on 

NRC working groups and committees developing the national source 

tracking system, has had the opportunity to provide input on the design 

of the system and the potential usefulness of the system to assist its 

source recovery efforts. Regardless of DOE’s opportunities to provide 

input to NRC, DOE officials raised concerns to us during the course of 

our work about the usefulness of NRC’s source tracking system. 

Furthermore, in commenting on our draft report, DOE stated that there 

is a need for a more rigorous national-level tracking capability to assist 

the department in identifying and recovering unwanted sources. 

We incorporated technical changes in this report, where appropriate, on 

the basis of detailed comments provided by both agencies. 
Page 42 GAO-05-967 Security of Unwanted Radiological Sources

We will send copies of this report to the appropriate congressional 

committees. We will make copies available to others upon request. In 

addition, the report will be available at no charge on the GAO Web site at 

http://www.gao.gov.

If you or your staff have any questions about this report, please contact me 

at ((202) 512-3841 or at aloisee@gao.gov. Contact points for our Offices of 

Congressional Relations and Public Affairs may be found on the last page 

of this report. GAO staff who made major contributions to this report are 

listed in appendix V.

Sincerely yours,

Gene Aloise, Director 

Natural Resources and Environment
Page 43 GAO-05-967 Security of Unwanted Radiological Sources

Appendix I

Scope and Methodology ApApenednxidexiIs

In our review, we examined (1) the status of the Department of Energy’s 

(DOE) efforts to recover unwanted sealed radiological sources and develop 

a disposal option for greater-than-class C (GTCC) waste, (2) DOE actions 

taken to recover and dispose of unwanted non-GTCC waste from sealed 

radiological sources, and (3) the extent to which DOE can identify and 

track unwanted sealed radiological sources for recovery and disposal. To 

better understand these issues, we met with officials at DOE, the National 

Nuclear Security Administration, and the Nuclear Regulatory Commission 

(NRC), and we visited the office of DOE’s source recovery project at Los 

Alamos National Laboratory and observed laboratory personnel recovering 

unwanted sealed radiological sources from a university. We also 

interviewed officials at nonfederal organizations, including the Health 

Physics Society, the Organization of Agreement States, and the Conference 

on Radiation Control Program Directors (CRCPD), as well as some 

recognized experts in the field. We also met with representatives from 

commercial entities that are licensed to possess high-risk radioactive 

sources and state regulatory officials in California and Ohio. 

More specifically, to examine the status of DOE efforts to recover 

unwanted sealed radiological sources and develop a disposal option for 

GTCC waste, we interviewed DOE officials from the U.S. Radiological 

Threat Reduction Program, Office of Environmental Management, and 

Office of Security. We reviewed applicable statutes, regulations, and agency 

guidance as well as relevant DOE and NRC studies, reports, documents, 

and agency plans. We obtained information from the source recovery 

project inventory database to determine the number and type of sources 

recovered as of June 7, 2005. To determine the reliability of these data, we 

first asked officials a series of data reliability questions that addressed 

areas such as data entry, data access, quality control procedures, and data 

accuracy and completeness. We also inspected data records, reviewed 

manuals and documents relating to DOE data collection and verification 

methods, and interviewed DOE officials. We asked follow-up questions as 

necessary. In consultation with a GAO expert in research methodology, we 

analyzed the officials’ responses for relevant weaknesses in data reliability 

that would make their data unusable for our analysis and reporting 

purposes. On the basis of these efforts, we determined that these data were 

sufficiently reliable for summarizing volumes of recovered sealed 

radiological sources. 

We also sought a better understanding of how sealed radiological sources 

are classified as waste. We developed a structured interview guide to 

collect information from commercial waste brokers that possess GTCC and 
Appendix I

Scope and Methodology

Page 44 GAO-05-967 Security of Unwanted Radiological Sources

non-GTCC waste from sealed radiological sources. This interview guide 

asked questions on areas such as the wastes these brokers often collect 

and the potential waste classes of common types of sealed radiological 

source devices. Because the practical difficulties of developing and 

administering a structured interview guide may introduce errors—resulting 

from how a particular question is interpreted, for example, or from 

differences in the sources of information available to respondents in 

answering a question—we included steps in the development and 

administration of the structured interview guide for the purpose of 

minimizing such errors. We pretested the instrument with three 

commercial waste brokers by telephone and modified it as appropriate to 

reflect questions and comments received during the pretests. 

To determine which commercial waste brokers to interview, we first used a 

list of commercial waste brokers compiled by CRCPD’s National Orphan 

Radioactive Material Disposition Program. This list contained 18 waste 

brokers that met the CRCPD criteria of being in good standing with CRCPD 

and serving more than 1 million customers, serving non-DOE customers, or 

serving more than one state. However, because this list is not 

comprehensive and there is no single source listing of commercial waste 

brokers, we also asked each broker we interviewed for the names of 

additional brokers who could provide useful information or insights into 

these issues. We continued this expert referral technique until the 

references we received became repetitive. In all, we used our structured 

interview guide to interview a nonprobablility sample of 12 commercial 

waste brokers in various geographical locations.1

 We then used the results 

of these structured interviews to create a table summarizing common 

sealed radiological sources devices and their potential waste class (see 

app. II). We shared preliminary drafts of this table with experts at DOE and 

NRC and with leading scientists in the field of sealed radiological source 

security from nonfederal organizations, such as the Monterrey Institute of 

International Studies and the Low-Level Waste Forum. We received and 

incorporated their comments as appropriate on the structure and contents 

of the table. On the basis of this process, we determined that these data 

were sufficiently reliable for the purposes of this report. 

1

Results from nonprobability samples cannot be used to make inferences about a population 

because in a nonprobability sample, some elements of the population being studied have no 

chance or an unknown chance of being selected as part of the sample.
Appendix I

Scope and Methodology

Page 45 GAO-05-967 Security of Unwanted Radiological Sources

To examine the actions DOE has taken to recover and dispose of unwanted 

sealed radiological sources, we interviewed source recovery project 

personnel and officials from the U.S. Radiological Threat Reduction 

Program. We also conducted interviews with representatives from 

nonfederal entities, including the Monterrey Institute of International 

Studies, the Health Physics Society, CRCPD, the National Research 

Council, and the Council on Foreign Relations. We discussed with these 

agency officials and representatives the likelihood of DOE’s needing to 

recover more non-GTCC waste from unwanted sealed radiological sources 

in the future if the Barnwell, South Carolina, disposal site restricts access 

for licensees in 36 states by mid-2008 as planned. To obtain a better 

understanding of how much non-GTCC waste might be stored if licensees 

in these states are denied disposal access for this waste, we gathered 

information on the quantity of non-GTCC waste disposed at the two 

commercial disposal sites that can accept classes B and C waste in 

Richland, Washington, and Barnwell, South Carolina, between 2001 and 

2004. To determine the reliability of these data, we first asked disposal 

operators a series of data reliability questions that addressed specific 

areas, such as data entry, data access, quality control procedures, and data 

accuracy and completeness. We added follow-up questions as necessary. In 

consultation with a GAO expert in research methodology, we analyzed their 

responses for relevant weaknesses in data reliability that would make their 

data unusable for our analysis and reporting purposes. On the basis of 

these efforts, we determined that these data were sufficiently reliable for 

summarizing volumes of disposed waste at these disposal sites. 

To determine the extent to which DOE can identify and track unwanted 

sealed radiological sources for recovery and disposal, we interviewed DOE 

and NRC officials regarding the scope, capabilities, and limitations of their 

existing databases for tracking these sources. We reviewed past estimates 

of the number of sealed radiological sources in the United States, including 

the scope and methodologies used to create these estimates. To examine 

NRC efforts to develop a national source tracking system for certain sealed 

radiological sources, we interviewed NRC and DOE officials who 

participated in the system’s initial formulation. We reviewed planning and 

management documents, including related NRC submissions to the Office 

of Management and Budget, NRC’s business case analyses, and the 

proposed rule for implementing a national source tracking system. We also 

reviewed the survey instrument NRC used to populate the interim 

database. Finally, we interviewed state officials from Illinois, New York, 

Ohio, and Oregon to determine whether any states currently track sealed 
Appendix I

Scope and Methodology

Page 46 GAO-05-967 Security of Unwanted Radiological Sources

radiological sources and gathered these officials’ views on the need for a 

national source tracking system. 

We conducted our review between June 2004 and September 2005 in 

accordance with generally accepted government auditing standards. 
Page 47 GAO-05-967 Security of Unwanted Radiological Sources

Appendix II

Selected Sealed Radiological Source Devices 

and Their Potential Waste Classes ApendxiI

Table 4 presents selected common devices that utilize sealed radioactive 

sources and the NRC waste classes in which sources from these devices 

might be disposed. This table shows the variability in the possible sources 

used in devices, their relative risks according to the International Atomic 

Energy Agency (IAEA) categorization scheme, and the range of waste 

classes associated with the sources that could be used in these devices. 

The radionuclides and the ranges of radioactivity listed next to each device 

are presented for illustrative purposes—each device might use one of these 

radionuclides in one or more sources. The IAEA source category 

corresponds to each radionuclide and radioactivity range, based on an 

IAEA technical document, as noted. The potential waste classes are 

associated with each device and not with the specific radionuclides that 

might be in these devices. In other words, not all radionuclides that could 

be used in a source within a device produce the range of waste classes 

associated with the device. 

Table 4: Selected Sealed Radiological Source Devices and Their Potential Waste Classes

Device Radionuclide

Approximate initial

curiea

 range of

radioactivity per

device or application

IAEA source

categoryb

Potential NRC waste 

classb when disposed

Radioisotopic thermoelectric 

generators 

Strontium-90 9,000 - 680,000 1,2 B/C, GTCC

Plutonium-238 28 - 280 2

Panoramic irradiatorsc Cobalt-60 500,000 - 5,000,000 1 A, B/C

Self-shielded irradiatorsc Cesium-137 2,500 - 42,000 1,2 B/C, GTCC

Cobalt-60 1,500 - 50,000 1

Blood-tissue irradiatorsc Cesium-137 1,000 - 12,000 1,2 B/C, GTCC

Cobalt-60 1,500 - 3,000 1

Gamma knife (fixed, multibeam 

teletherapy)c

Cobalt-60 4,000 - 10,000 1 B/C

Teletherapy Cobalt-60 1,000 - 15,000 1 B/C

Cesium-137 500 - 1,500 2

Calibration sources Cobalt-60 .55 - 16,000 1,2,3,4 A, B/C, GTCC

Cesium-137 1.5 - 14,000 1,2,3,4

Americium-241 1 - 25 2,3,4

Plutonium-239/Beryllium 2 - 25 2,3

Strontium-90 0.05 - 2 4
Appendix II

Selected Sealed Radiological Source Devices 

and Their Potential Waste Classes

Page 48 GAO-05-967 Security of Unwanted Radiological Sources

Industrial radiography Cobalt-60 11 - 330 2 A, B/C, GTCCd

Iridium-192 5 - 290 2,3

Cesium-137 5 - 12 3

Selenium-75 80 2

Ytterbium-169 2.5 - 20 3,4

Thulium-170 20 - 200 4

Fixed industrial gauges (level, 

dredger, conveyor, blast furnace, and 

spinning pipe)

Cesium-137 0.1 - 40 2,3,4 A, B/C, GTCC

Cobalt-60 0.1 - 20 2,3,4

Californium-252 0.037 4

Well-logging sources Americium-241/Beryllium 0.5 - 70 2,3,4 A, B/C, GTCC

Radium-226 20 2

Cobalt-60 0.2 -10 2, 3

Plutonium-238/Beryllium 5 - 70 2, 3

Tritium 1 - 20 5

Cesium-137 0.5 - 20 3,4

Californium-252 0.027 - 1.61 3,4

Brachytherapy (high/medium and low 

dose rate)

Cobalt-60 1 - 20 2,3 A, B/C, GTCC

Cesium-137 0.01 - 8 3,4,5

Iridium-192 0.02 - 15 3,4,5

Radium-226 0.005 - 0.05 4,5

Iodine-125 0.005 - 1.3 4,5

Gold-198 0.08 4

Californium-252 0.083 - 0.54 3,4

Strontium-90 0.02 - 0.12 4,5

Ruthenium/Rhodium-106 0.00022 - 0.0006 5

Palladium-103 0.03 - 0.056 5

Pacemakers Plutonium-238 2.9 - 8 3 B/C, GTCC

Research reactor startup source Americium-241/Beryllium 2 - 5 3 B/C, GTCC

Portable gauges (moisture detectors, 

density and moisture/density)c

Americium-241/Beryllium 0.01 - 3 3,4,5 A, B/C, GTCC

Cesium-137 0.008 - 0.011 5

Radium-226 0.002 - 0.005 5

Californium-252 0.00003 - 0.00007 5

(Continued From Previous Page)

Device Radionuclide

Approximate initial

curiea

 range of

radioactivity per

device or application

IAEA source

categoryb

Potential NRC waste 

classb

 when disposed
Appendix II

Selected Sealed Radiological Source Devices 

and Their Potential Waste Classes

Page 49 GAO-05-967 Security of Unwanted Radiological Sources

Sources: See the note below.

Note: The primary source for the first four columns is IAEA, Categorization of Radioactive Sources, 

TECDOC-1344 (Vienna, Austria: July 2003). The primary sources for the waste classification column 

are interviews we conducted with commercial low-level radioactive waste brokers. We received 

comments and suggestions on drafts of this table from nine scientists and regulators in the field and 

accepted revisions as appropriate. These revisions affected roughly 30 percent of the fields in the 

table, primarily those in the range of radioactivity and waste classification columns. 

a

A curie is a measure of the rate of radioactive decay; it is equivalent to the radioactivity of 1 gram of 

radium or 37 billion disintegrations per second

b

See 10 C.F.R. part 61 for the NRC waste classification system.

c

A device may utilize multiple sealed radiological sources. The range of radioactivity per use for these 

devices reflects the aggregate activity.

d

There was unresolved disagreement between the waste brokers and some of the regulators regarding 

whether industrial radiography sources could be GTCC.

Static eliminators Americium-241 0.03 - 0.11 4 A, B/C, GTCC

Polonium-210 0.03 - 0.11 4

Thickness/fill-level gauges Krypton-85 0.05 - 1 5 A, B/C, GTCC

Strontium-90 0.01 - 0.2 5

Americium-241 0.012 - 0.6 4,5

Cesium-137 0.05 - 0.065 4

Promethium-147 0.05 5

Curium-244 0.2 - 1 4

Bone densitometry Cadmium-109 0.02 5 B/C, GTCC

Gadolinium-153 0.02 - 1.5 4,5

Iodine-125 0.04 - 0.8 4,5

Americium-241 0.027 - 0.27 4

X-ray fluorescence analyzers Iron-55 0.003 - 0.14 5 A, B/C, GTCC

Americium-241 0.004 - 0.20 4,5

Cadmium-109 0.005 - 0.15 5

Cobalt-57 0.005 - 0.04 5

Electron capture detectors Nickel-63 0.005 - 0.50 5 A, B/C

Tritium 0.05 - 1.0 5

Lightning preventers Americium-241 0.0013 - 0.013 5 A, B/C, GTCC

Radium-226 0.000007 - 0.00008 5

Tritium 0.2 5

PET checking Germanium-68 0.001 - 0.01 5 A, B/C

Mossbauer spectrometry Cobalt-57 0.005 - 0.1 5 A, B/C

(Continued From Previous Page)

Device Radionuclide

Approximate initial

curiea

 range of

radioactivity per

device or application

IAEA source

categoryb

Potential NRC waste 

classb

 when disposed
Page 50 GAO-05-967 Security of Unwanted Radiological Sources

Appendix III

Comments from the Department of Energy ApendxiI
Appendix III

Comments from the Department of Energy

Page 51 GAO-05-967 Security of Unwanted Radiological Sources
Appendix III

Comments from the Department of Energy

Page 52 GAO-05-967 Security of Unwanted Radiological Sources
Page 53 GAO-05-967 Security of Unwanted Radiological Sources

Appendix IV

Comments from the Nuclear Regulatory 

Commission ApendxiIV
Appendix IV

Comments from the Nuclear Regulatory 

Commission

Page 54 GAO-05-967 Security of Unwanted Radiological Sources
Appendix IV

Comments from the Nuclear Regulatory 

Commission

Page 55 GAO-05-967 Security of Unwanted Radiological Sources
Page 56 GAO-05-967 Security of Unwanted Radiological Sources

Appendix V

GAO Contact and Staff Acknowledgments ApendxiV

GAO Contact Gene Aloise (202) 512-3841

Staff 

Acknowledgments

In addition to the person named above, Casey Brown, Ryan Coles, John 

Delicath, Daniel Feehan, Doreen Feldman, Susan Iott, Thomas Laetz, 

Cynthia Norris, Anthony Padilla, Judy Pagano, Leslie Pollock, and Barbara 

Timmerman made key contributions to this report.

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