Tools for placing the radiological health hazard in perspective following a severe emergency at a light water reactor (LWR) or its spent fuel pool.

Experience from past nuclear and radiological emergencies shows that placing the radiological health hazard in perspective and having a definition of "safe" are required in order to prevent members of the public, those responsible for protecting the public (i.e., decision makers), and others from taking inappropriate and damaging actions that are not justified based on the radiological health hazard. The principle concerns of the public during a severe nuclear power plant or spent fuel pool emergency are "Am I safe?" and "What should I do to be safe?" However, these questions have not been answered to the satisfaction of the public, despite various protective actions being implemented to ensure their safety. Instead, calculated doses or various measured quantities (e.g., ambient dose rate or radionuclide concentrations) are used to describe the situation to the public without placing them into perspective in terms of the possible radiological health hazard, or if they have, it has been done incorrectly. This has contributed to members of the public taking actions that do more harm than good in the belief that they are protecting themselves. Based on established international guidance, this paper provides a definition of "safe" for the radiological health hazard for use in nuclear or radiological emergencies and a system for putting the radiological health hazard in perspective for quantities most commonly measured after a release resulting from a severe emergency at a light water reactor or its spent fuel pool.

Replacement of 137Cs irradiators with x-ray irradiators.

Self-shielded 137Cs irradiators have been used for many years to irradiate blood products to prevent graft vs. host disease and to irradiate cells and small animals in research. A report by the National Academy of Sciences recommends that careful consideration be given to replacement of 137Cs irradiators with x-ray irradiators. Several manufacturers and users of x-ray irradiators were contacted to determine costs of replacing and maintaining 137Cs irradiators with x-ray units and to assess users' experience with x-ray irradiators. Purchase costs of x-ray units are similar to 137Cs irradiators, but maintenance costs are significantly higher if annual service contracts are used. Performance of the two irradiator types appears to be equivalent, but in some cases x-ray irradiations may need to be performed in multiple configurations to achieve adequate uniformity in dose. No literature reports were found that evaluated the biological effectiveness of x rays vs. 137Cs gamma rays; therefore, a careful study should be conducted to determine the biological effectiveness of x rays vs. 137Cs gamma rays for biological responses relevant to transfusion medicine and immunological research. Throughput may be problematic for large transfusion medicine programs, and back-up plans may be necessary in case the x-ray unit needs to be taken out of service for extended maintenance. Disposition of a 137Cs irradiator will add to the cost of replacement with an x-ray unit, but disposal may be possible through the U.S. Department of Energy's Off-Site Source Recovery Program.

Mustard to wine...aspects of the IAEA's recent work on the control of radioactive sources.

This paper reviews the International Atomic Energy Agency's "International Conference on the Safety and Security of Radioactive Sources: Towards a Global System for the Continuous Control of Sources throughout their Life Cycle," which was held in Bordeaux, France, from 27 June to 1 July 2005. Some high points of the progress in controlling radioactive sources since the similar meeting in Dijon (1998) are discussed. The impact of the IAEA's Code of Conduct on the Safety and Security of Radioactive Sources for radioactive material licensees in the United States of America is summarized.

International efforts in countering radiological terrorism.

An analysis of the possible goals of terrorists and the means of achieving them leads to an assessment of the most likely target materials and facilities for radiological terrorism. International efforts in countering these terrorist goals cover several objectives. The first is to prevent acquisition of the target radioactive materials, or access to the target facilities. This has to be achieved throughout the life cycle for radioactive sources. The second objective is to detect attempts to acquire, or actual acquisition of, radioactive materials. The third objective is to effectively detect and respond to the use (or threat of use) of these materials, or sabotage of the facilities. An additional goal is to minimize the consequences of any such use or sabotage. The number of international bodies, groups, agencies, and organizations contributing to these goals is very large and almost impossible to catalogue. However, this paper groups the types of efforts that are being undertaken, identifies the key agencies involved, and provides some specific examples of their work.