Beneficial Uses of Nuclear Technology:
The Role of the Regulator in Ensuring the Protection of Public Health and Safety
Dr. Shirley Ann Jackson, Chairman
U.S. Nuclear Regulatory Commission
International Meeting on Nuclear Energy in Medicine and other Peaceful Applications
Hanoi, Vietnam, March 29, 1999
Good morning, ladies and gentlemen. I was delighted when I received the invitation to address this assembly, and I am pleased to be with you today. The title of this conference, "Nuclear Energy in Medicine and Other Peaceful Applications," encompasses a broad area that is less known to the general public than other uses of nuclear technology, such as nuclear power production and nuclear weapons. However, interestingly enough, this area of nuclear technology has the potential to have a substantial positive impact on the day-to-day lives of nearly every individual. Nuclear technologies allow doctors and scientists to combat disease through the diagnosis and treatment of cancers and other ailments, through the sterilization of food and medical products, and through the sterilization and subsequent destruction of pests such as the screw worm and tsetse fly. These technologies also offer ways to construct buildings and pipelines with greater safety through industrial radiography, and to manufacture goods more efficiently through the use of industrial gauges.
As a nuclear safety regulator, while I clearly recognize the benefits to society of the use of these technologies, I also am aware that each of these technologies carries (like all technologies) a risk. As a result, I strongly support the use of regulatory programs to ensure that these technologies are used in a manner that is protective of the public health and safety, and the environment-and, at the same time, not unnecessarily burdensome. For my presentation today, I will focus briefly on several areas of nuclear technology. I will then address the regulatory requirements that the U.S. Nuclear Regulatory Commission (NRC) has found necessary and appropriate in ensuring the protection of the public health and safety, while allowing the use of these technologies.
As with all beneficial uses of nuclear technology, medical uses of radioactive material introduce accepted risks to patients, workers, the public, and the environment. Current medical applications of radioactive materials employ a number of different radioisotopes in a variety of chemical and physical forms that lead to potential radiation doses and contamination possibilities with varying levels of risk significance. Our acceptance of these technologies is based on the premise that any added risk is outweighed sufficiently by the benefit gained.
Both sealed and unsealed forms of various radiochemical compounds are used in medicine. A sealed source is designed to maintain the material within an engineered source container under tested physical and chemical stresses. As regulators, we focus on the design and testing of sealed sources and the medical devices in which they are used, to minimize unnecessary contamination and exposures to the patients and the workers.
Nuclear medicine also employs unsealed radiolabeled compounds, known as radiopharmaceuticals, for diagnostic and therapeutic procedures via intravenous injection, oral ingestion, or inhalation. Diagnostic nuclear medicine procedures detect radioactive emissions from the internally deposited radioactive material to create a computerized image of specific organ tissues and organ functions. For example, injection of a radiopharmaceutical tagged with metastable technetium-99, that has specific preference for seeking out bone tissue, is often used to produce an image of the skeletal structure of a patient. Iodine-131 or iodine-123 can be used in radiopharmaceuticals for uptake by the thyroid, to determinate whether the organ is functioning properly. In contrast to these diagnostic studies, radiopharmaceutical therapy typically involves higher levels of radioactivity for delivering larger doses. As such, controls on the handling and administration of therapeutic radiopharmacueticals are greater, involving more oversight in (1) the measurement of the radiopharmaceuticals, (2) access to the patient by the family members, and (3) control of contaminated personal items.
With unsealed radioactive material, as well as with leaking sealed sources, the potential exists for contamination leading to the unplanned external and/or internal doses from radioactive material to occupational workers and others. A demonstrated practical need exists for regulatory oversight to focus on the prevention of these unplanned doses, thereby reducing the risk to individuals and the environment.
In addition to nuclear medicine, radiation therapy for cancer and other medical conditions is achieved via teletherapy and brachytherapy. The objective of teletherapy is to focus the radiation from a sealed radiation source into a radiation beam that can deliver a precisely measured radiation dose to a defined cancerous tissue (tumor) volume. This type of external beam radiation therapy also has evolved into gamma stereotactic radiosurgery, which employs an intricate device with many sources to deliver radiation therapy to precisely defined intracranial targets (e.g., brain tumors and arteriovenous malformations). With these more complex delivery systems and higher radiation levels, increased potential exists for significant unplanned radiation doses from software and hardware malfunctions.
A variety of smaller sizes and quantities of sealed sources are employed in brachytherapy to direct localized treatment of cancer. The sealed sources can be inserted into a cavity using an applicator, implanted directly into tissue, or introduced via an implanted catheter. The evolution of the manual techniques and applicators for these source insertions has resulted in the development of remote afterloading devices that allow medical personnel to complete a number of source insertions from a shielded remote location, thereby reducing the radiation dose to medical personnel. The use of remote technology allows the use of higher activity sources than can be used with manual implants. This results in a quicker treatment that is safer for the workers and less demanding on the patient.
Both teletherapy and high dose-rate brachytherapy apply high levels of radiation that require specific attention to controlling the exposure and, in particular, the potential doses that can be received by medical personnel and/or the public during relatively short periods of inadvertent exposure. Further, the complex device systems involved with teletherapy and remote afterloader therapy depend upon computerized electronic interfaces for planning and delivering treatment at high radiation levels, and are designed to shield the radiation sources during non-use periods. Therefore, regulations can direct user attention toward testing the accuracy and reliability of the device systems-both to deliver the planned treatment correctly and to shield against unplanned doses. In addition, the preliminary design, testing, and approval of a device to achieve these goals is a specific regulatory focus that, once again, is aimed at maintaining risk at a low level relative to the medical benefit achieved.
Significant challenges are presented both by the dynamics of current medical applications and by the increasing rate at which new medical applications and related technology are being developed. Radiation safety considerations must be adapted to address each new medical technology during the course of research, development, and use. An effective regulatory program must be flexible and anticipatory in directing attention to, and addressing, changing radiation safety needs to continually assure safety without imposing an unnecessary regulatory burden. Frequent and robust regulatory communication with our medical licensees and other stakeholders can help to ensure that safety is in step with emerging and changing technologies.
A current example is presented by the recent research introduction of intravascular brachytherapy, a process in which radiation is used after balloon angioplasty to prevent restenosis (a partial obstruction of the artery) from occurring as the wound heals. Preliminary research has shown promising results, and many systems and radioactive isotopes are being introduced for research and refinement. These device systems, the minute treatment regions involved, the involvement of multiple medical specialties in the treatment, and the potential to spread radioactive material contaminants into the blood stream, all are issues that expand upon the traditional concepts and, consequently, upon the regulation of brachytherapy, sealed sources, and nuclear medicine. These issues reinforce the need to ensure that any new and unique radiation safety considerations are identified, and that adequate procedures are implemented early during the development of the technology.
In addition to the research for the development of new medical technologies, chemical, cellular and molecular research take advantage of the emissions from radioactive tracers to track the final disposition of radioactive material and to gain information about intermediate products or stages. In the field of genetics, such tracers commonly utilize carbon-14, tritium, and phosphorous-32 to produce radiolabeled nucleic acids. These nucleic acids are then used in DNA sequencing as markers in gel separations. The markers then can be recorded via the image produced from the radioactive emissions, a process referred to as auto-radiography. The resulting contaminated gels and other materials in such laboratory studies present their own radioactive contamination and waste issues to form yet another focus of radiation safety regulation.
Sources with high levels of radioactivity also may be used to create genetic mutations and sterilize bacteria, viruses, plants, and animals. Small biological specimens can be irradiated in self-shielded irradiators. As mentioned earlier, sterilized pests, such as tsetse flies, can be released into the wild to diminish the breeding successes of their wild counterparts. The small irradiator devices used for such activities undergo regulatory review to ensure sufficient shielding and engineered safety mechanisms to protect the user from direct exposure to the large radioactive sources.
Low-level radioactive tracers can be used in environmental research to identify, for example, the metabolism and/or migration habits of a free ranging endangered animal. Radioisotopes are used to develop new strains of crop foods, to increase the effectiveness of fertilizers, and to analyze environmental pathways and degradation of pesticides. Geological research also may incorporate tracer studies. For example, ground injection of radiolabeled steam with substantial quantities of tritium can facilitate the mapping of oil fields. Such studies warrant prior careful regulatory assessment of the impact on the environment and the risks from potential pathways to humans via food, water, soil, and airborne contamination. Again, regulatory attention is focused on conscious decision-making to minimize the risk while maintaining benefit from radioactive material use.
Outside of the medical and academic arena, nuclear technologies are also widely employed in industrial and commercial applications. Sealed and unsealed radioisotopes are used in many modern industrial processes, such as identifying flaws in critical parts and welds, ensuring the quality of manufactured products, and destroying germs and bacteria that contaminate medical supplies, blood supplies, and food. Nuclear materials also may be used to authenticate valuable works of art, to solve crimes by spotting trace elements, and to eliminate dust and/or static electricity from film and compact disks. Radioisotopes can be used to improve the features of consumer products such as electron tubes, incandescent lamp starters, watches, and smoke detectors.
The list of industrial applications is long and varied, with new uses being developed continuously. Again, radiation safety regulation must keep step with any new radiation safety considerations. Industrial radiography, well logging, and panoramic irradiators are examples of three industrial applications with unique radiation safety issues that are addressed separately in the NRC regulations.
In the use of nuclear technology in industrial radiography, radiation is used to inspect the internal structure of metal parts and welds for defects, typically by remotely removing a high activity radiation source from its shielded container and placing it into a "guide tube" in the area of interest. Radiation passing through the object to be tested strikes special radiographic film placed on the side of the test object opposite from the source, and an image of cracks, breaks, or other flaws is produced. Testing may be performed within fixed radiography facilities or at temporary job sites. Portable devices can contain radiation sources of up to 200 curies of iridium-192 or up to 100 curies of cobalt-60. Devices at fixed facilities can contain sources of up to several hundred curies. Since radiography involves unshielded high activity sources that produce high radiation dose rates in areas that can be occupied by workers and members of the public, special attention must be paid to training the users of this technology.
The NRC radiography regulations address the risk to both workers and members of the public. Specifically, the regulations focus on adopting standards for equipment design and construction, ensuring properly operating devices, identifying and restricting radiation areas, and maintaining inventory control. While training always has been emphasized, the NRC has been working recently with professional groups to implement certification requirements for radiographers. Setting training and personnel protection standards is a key role for regulators of industrial uses of radiation.
In the development and exploration of mineral resources, nuclear technology is used to determine the physical and chemical characteristics of the mineral formations through well logging and tracer studies. Well logging uses instruments lowered into holes drilled in the earth to obtain information on certain properties of the underground rock formations-for example, the type of rock, porosity, density, and hydrocarbon content-to locate oil, gas, coal, and other mineral deposits. A common technique is to lower sealed radioactive sources with associated radiation detectors, known as logging tools, into a well on a wireline. Americium-241 and cesium-137 are the most commonly used radioactive sources used in this type of well logging. Information collected by the detectors from the radiation sources is sent to the surface (from several hundred feet to over 30,000 feet) through the wireline as the tool is raised to the surface. A newer technology, referred to as "logging while drilling," does not use the wireline technique. In this newer method, the well logging tool is attached to the drill bit and information from the detector regarding the physical properties of the geologic formations is available to the drilling operator as the operations proceed. The newer technology eliminates the need to retract the drill bit from the well to make the measurements.
In subsurface tracer studies, a relatively small amount of radioactive material, principally iodine-131, is used in liquid form. The process involves the injection of the tracer into the well and through the subsequent measurement of the amounts of the tracer in mineral samples from the well and adjacent wells, such as water or oil, the licensee is able to determine the movement or position of the mineral formation.
Because these operations may involve handling unshielded sources with appreciable amounts of radioactivity and unsealed radioactive liquids in confined and hazardous working conditions, the risk of significant radiation doses to workers and the environment is a regulatory focus. Additionally, sealed sources that are lost during well logging may require follow-up actions, such as plugging and marking the site, to ensure that future drilling operations do not drill accidently into the abandoned source and spread contamination over the drilling site.
In construction and manufacturing, nuclear gauges provide an inexpensive, yet highly reliable and accurate method of measuring the thickness, density, or make-up of a wide variety of materials or surfaces. Fixed gauges, typically containing cesium-137, are used most often in factories as a way of monitoring a production process and ensuring quality control. Portable gauges (typically containing cesium-137 and americium-241) are used in industries such as agriculture, construction, and civil engineering for such measurements as soil moisture and asphalt density. Because the sources generally are shielded with the radiation beam oriented toward process materials, there is small risk to the users. However, the reduced radiation risk in an industrial setting can result in a sense of complacency with respect to the radiation safety requirements for these devices. This complacency has resulted in the loss of accountability and damage to these devices. Gauging devices have been smelted, flattened by bulldozers, stolen, and disassembled and sold for scrap. Often the users view these devices only as tools, rather than focusing on the presence of radioactive material that requires safety and control. Consequently, worker and public health and safety are best ensured by a regulatory emphasis on the ruggedness of the device design and construction to suit the environment in which it will be used. In addition, an appropriate radiation safety program needs to be implemented by the users, to ensure that the devices are properly stored and maintained, and that damages are assessed and responded to in a timely fashion.
The food, medical, and manufacturing industries often use large panoramic irradiators, as opposed to self-shielded irradiators, to deliver large doses of radiation to bulk material in a short period of time to sterilize the materials or to change their physical properties. Panoramic irradiators use gamma radiation from cobalt-60 or cesium-137 to irradiate products. Large panoramic irradiators are those capable of delivering a dose exceeding 5 Sieverts (Sv), or 500 rem, in one hour at a distance of one meter. The radiation sources, which may total several million curies, typically are stored in a water pool and behind thick shielding walls when not in use. Medical supplies, such as rubber gloves, cloth bandages, syringes, and contact lens solution can be sterilized in an irradiator. In manufacturing, wood and plastic composites are irradiated with gamma radiation to increase their resistance to abrasion and to decrease maintenance. Food is irradiated to destroy bacteria, to control insect and parasite infestation, to inhibit sprouting, and to delay ripening.
At some facilities, the material to be irradiated is manually placed in the exposure room while the sources are shielded, while at other facilities the material passes through the exposure room on a conveyor belt system via a shielded maze. In either case, the sources are removed from their shielded position and produce a very intense and very broad radiation field capable of delivering high doses to the entire volume of the material. Because of the very high radiation levels present in the exposure room, absolute control must be maintained to ensure that workers and the public are not allowed to be exposed. Consequently, the initial emphasis of a regulatory program is a detailed focus on facility construction, design, and acceptance testing. Systems of interlocks, motion sensors, and radiation monitors are necessary to ensure that the sources will become shielded should there be an inadvertent entry during an exposure. During operations, safety emphasis includes training, worker monitoring, routine testing, emergency preparedness, fire hazard analysis, and monitoring source movement and storage. Irradiation of explosive or flammable materials introduces heightened risks and requires additional, specific regulatory focus.
NRC Approach to Generally Licensed Source Accountability
In certain areas the regulatory program to oversee nuclear technologies has proven to be inadequate to properly control the risks associated with the technology. The regulatory bodies must be cognizant of these issues and refocus their programs to address the inadequacies. As an example, I now would like to address a specific issue, involving nuclear material of the type I have described, which has been a matter of heightened NRC focus.
Worldwide, the failure to control nuclear devices has resulted, in certain cases, in injury and/or loss of property. In the U.S., this has not been a concern with "specifically licensed devices"-in other words, those cases in which an individual specifically is licensed to possess and use the device. An NRC specific license carries with it annual fees and inspections that serve as a reminder to the owner regarding the proper attention and control to be applied to the device. However, there is another class of devices in the U.S. that currently does not have the same level of accountability. These are known in the U.S. as "generally licensed" devices, and they require no licensing or inspection of the user. Devices that can be possessed under a general license include fixed nuclear gauges, static eliminators, and luminous exit signs. A generally licensed device usually consists of radioactive material, contained in a sealed source, within a shielded device. The device is designed with inherent safety features so that it can be used by persons with no radiation training or experience. Thus, the general license is meant to simplify the licensing process so that a case-by-case determination of the adequacy of the radiation training and experience of each user is not necessary. I would like to discuss briefly our efforts at the NRC to improve accountability for generally licensed devices.
In 1959, the Atomic Energy Commission (which pre-dated the NRC) amended its regulations to extend the general license program to include the use of byproduct material contained in certain luminous, measuring, gauging, and controlling devices. Under current regulations, certain persons may receive and use a device containing byproduct material under a general license if the device has been manufactured and distributed in accordance with the specifications contained in a specific license issued by the NRC or by an Agreement State. A specific license is issued to authorize the distribution of these generally licensed devices, based upon a determination by the regulatory authority that the safety features of the device and the instructions for safe operation of that device are adequate to meet regulatory requirements. The general licensee is required to comply with the safety instructions contained in (or referenced on) the label of the device, and to have the testing or servicing of the device performed by an authorized individual.
Under the NRC general license regulatory program, about 45,000 general licensees exist, possessing a total of about 600,000 devices that contain byproduct material. In the past, general licensees have not been contacted by the NRC on a regular basis because of the relatively small radiation risk posed by these devices and the very large number of general licensees. However, there have been a number of occurrences in which generally licensed devices containing radioactive material have not been handled and/or disposed of properly, with resultant radioactive contamination or radiation exposure to the public. Although no significant public health and safety hazards are known to have resulted from these U.S. incidents, they would not have occurred at all if proper handling, disposal, and accountability procedures had been followed.
The U.S. metals recycling industry, in particular, has been impacted by this problem. From 1983 to 1998, 125 radioactive sources subject to the Atomic Energy Act were reported as having been found in recycled scrap metal. Radioactive sources have been accidently melted in U.S. mills on 31 occasions. Twenty-seven of these involved sources subject to the Atomic Energy Act.
In the mid-1980's, as a result of some of these incidents, and in order to evaluate the effectiveness of the general license program, the NRC conducted a 3-year sampling of general licensees to determine whether an accounting problem existed with device users under general licenses, and, if so, what remedial action might be necessary.
The sampling revealed several areas of concern with the general license program. The NRC concluded that there was (1) a lack of awareness of appropriate regulations on the part of the general licensee, and (2) inadequate handling and accounting for these devices. Fifteen percent of all general licensees sampled could not account for all of their generally licensed devices. As a result, the NRC concluded that these problems could be remedied by a more frequent and timely contact between general licensees and the NRC. In April 1998, after an extended process of review and consideration, the Commission directed the NRC staff to draft a proposed rule to implement a registration and follow-up program for generally licensed sources and devices, and to incorporate requirements for permanently labeling these sources and devices. The NRC staff now has under development a rule that would allow us to gather information from general licensees and to develop an automated data information system for registration of generally licensed devices.
As a more extreme example of the loss of accountability for nuclear material, I would like to discuss the issue of abandoned sources. Worldwide there has been a rise in the number of abandoned sources making their way into the public domain. There have been recent reports of large activity sources in Eastern Europe (particularly in the Republic of Georgia), and in Turkey, that have the potential to expose members of the public to doses that could result in death or injury. In September 1998, to address the worldwide concern over the loss of control of radioactive sources, the International Atomic Energy Agency (IAEA) co-sponsored a Conference in Dijon, France on the Safety of Radiation Sources and the Security of Radioactive Materials, with the International Criminal Police Organization (INTERPOL), the World Customs Organization (WCO), and the European Commission (EC). That meeting concluded that: (1) radiation sources should not be allowed to "drop out of the regulatory control system"; (2) efforts should be made to find radiation sources that have escaped the inventory of the regulatory authority-either because they were in the country before the inventory was established, or because they were never licensed or were lost, abandoned, or stolen; and (3) efforts should be intensified to improve the detection of radioactive materials crossing national borders and moving within countries by carrying out radiation measurements and through intelligence-gathering.
The report of the Dijon Conference was considered by the 42nd meeting of the IAEA General Conference at its September 1998 meeting. In response, a resolution was adopted which requested that the Secretariat prepare a report for consideration of the IAEA Board of Governors at its March 1999 meeting, concerning: (1) how national systems for ensuring the safety of radiation sources and the security of radioactive materials can be operated at a high level of effectiveness; and (2) whether international undertakings can be initiated to improve the effective operation of such systems and to attract broad adherence. To address the General Conference Resolution request, the Secretariat convened a meeting of consultants in Buenos Aires in December 1998, and at NRC headquarters in late January 1999, to consider actions to be taken and to compile the report requested by the resolution.
The resultant report surveys current activities related to radiation source control and security, and makes recommendations for future international initiatives. Among the conclusions in the report, the consultants recommend that governments should be made aware of the severe-even fatal-accidents involving radiation sources that already have occurred and are continuing to occur, as a result of serious safety and security breaches and deficiencies. The report also concludes that governments should be informed that the absence or loss of control over radiation sources may pose a significant radiation exposure risk, and may have serious health and economic consequences not only in the country in which the given radiation source was used but also in other countries.
This report has been forwarded to the Board of Governors for consideration during its March 1999 meeting in Vienna. Based on the report conclusions and the further discussions at that Board meeting, the Secretariat intends to draw up a plan for further action on this issue.
Regulatory Program Approach
In outlining for you a number of beneficial uses of nuclear technology, I have tried to emphasize that during the development and operation of all nuclear technology, radiation safety risks must be identified and addressed to ensure continued protection of health and safety. I also have described a specific problem area, the accountability of generally licensed devices. The NRC regulations, for example, establish uniform requirements and definitions for common radiation safety risks in Title 10 of the U.S. Code of Federal Regulations (10 CFR), Part 20, including: occupational and public dose limits; surveys and monitoring; respiratory protection and other controls for internal doses; storage and control of licensed radioactive material; waste disposal; criteria for radiation levels at license termination; and records and reports. Specific requirements have originated in time-tested radiation health physics practices, and have been developed and refined using research, experience, and national and international standards established by recognized scientific bodies.
As discussed earlier, each nuclear technology introduces unique radiation safety concerns as well as generalized health physics concerns. Areas of regulatory focus include training, testing of device reliability, and requiring specific controls over certain radioactive material uses. For example, separate parts of the NRC regulations are provided to address various byproduct material applications and licensing. Part 30 provides "Rules of General Applicability to Domestic Licensing of Byproduct Material"; Part 34 applies to "Licenses for Industrial Radiography and Radiation Safety Requirements for Industrial Radiographic Operations"; Part 35 covers "Medical Use of Byproduct Material"; Part 36 involves "Licenses and Radiation Safety Requirements for Irradiators"; and Part 40 focuses on "Domestic Licensing of Source Material." Specific program requirements address provisions unique to each use that either have been shown to be necessary from operational experience or have been deemed necessary based on detailed evaluation of the risks from each use.
To carry out an effective regulatory program requires a regulatory infrastructure. The infrastructure for the regulation of nuclear technology typically involves, as its main components, a statutory (or legal) framework, regulatory requirements, and standards and guidance-addressed via licensing, inspection, and enforcement. In addition, a network of communication and coordinated interaction within this infrastructure is essential for addressing the various legal, scientific, and engineering disciplines utilized in most licensing actions, emergency response issues, and emergent safety concerns. The NRC has established avenues for involving and interacting with relevant professional organizations, public interest groups, environmental groups, manufacturers, licensees, and other stakeholders during the development of regulations and regulatory guidance.
These interactions, which occur through frequent public meetings, solicitations of comment, telephone inquiries, electronic communications, and other avenues, can facilitate open interaction and resolution of specific issues that are of stakeholder interest, and can enhance the political accountability of a regulatory body within the government framework. A balanced approach to ensuring stakeholder involvement and maintaining public confidence is a key facet of nuclear safety regulation.
Let me speak briefly to the issue of regulatory independence. As you may be aware, I also serve as the Chairman of the International Nuclear Regulators Association (INRA), a group founded in May 1997 to establish a forum for the most senior officials of national nuclear regulatory organizations to exchange views on broad regulatory policy issues-including technical, legal, economic, and administrative issues. At the most recent INRA meeting, in January of this year, one area of focus was this key regulatory concept of "effective independence." By unanimous agreement, the INRA members reaffirmed the need for an effective separation between the functions of a national nuclear regulatory organization and those other institutions-whether in government or industry-that are concerned with the promotion or use of nuclear energy. Effective independence includes political, legal/statutory, financial, technical, communication, and ethical accountability components. These elements are critical in creating and maintaining a decision-making framework that is characterized by neutrality and objectivity.
In summary then, the many nuclear technologies available in modern society offer benefits that, in many ways, can not be achieved through other means. As Vietnam begins to explore further the peaceful uses of nuclear materials, one essential area of focus will be the development of a regulatory program that is effectively independent, with a clear sense of its mission in regard to protecting public health and safety and the environment. I hope that my presentation has given you a broader understanding of both the potential for great benefit and the need to ensure that proper measures are put in to place to anticipate the risks and to ensure safety. I wish you every success in your endeavors, and I thank you once again for this opportunity to speak to you.