Chapter 1 Executive Summary The chancesof an accidental release of radioactive material have been made as remote as possible. Public concerns about safety are fueled by concerns about the testing program in general and exacerbated by the government’s policy of not announcingall tests. INTRODUCTION During a nuclear explosion,billions of atoms release their energy within a millionth of a second, pressures reach several million pounds per square inch, and temperaturesare as high as one-million degrees centigrade. A variety of radioactive elements are produced depending on the design of the explosive device and the contribution of fission and fusion to the explosion. The half-lives of the elements produced range from less than a second to more than a million years. Each year over a dozen nuclear weaponsare detonated undergroundat the NevadaTestSite.! The tests are used to develop new nuclear weapons and to assess the effects of nuclear explosions on military systems and other hardware. Eachtest is designed to preventthe release of radioactive material. The objective of each test is to obtain the desired experimental information and yet successfully contain the explosion underground (i.e., prevent radioactive material from reaching the atmosphere). doubt.’’ But the Containment Evaluation Panel has no guidelines that attempt to quantify or describe in probabilistic terms what constitutes for example, an ‘‘adequate degree of confidence.’’ Obviously, there can never be 100 percent confidence that a test will not release radioactive material. Whether ‘‘adequate confidence’’ translates into a chance of | in 100, | in 1,000, or 1 in 1,000,000, requires a decision about whatts an acceptable levelofrisk. In turn, decisions of acceptable level of risk can only be made by weighing the costs of an unintentional release against the benefits of testing. Consequently, those whofeel that testing is important for our national security will accept greater risk, and those who oppose nuclear testing will find even small risks unacceptable. Establishing an acceptable level of risk is difficult, not only because of the value judgments associated with nuclear testing, but also becausethe risk is not seen as voluntary by those outside the testing program. A public that readily accepts the risks associated with volun- tary activities—suchas sky diving or smoking— HOWSAFEIS SAFE ENOUGH? may still consider the much lowerrisks associated with nuclear testing unacceptable. Deciding whetherthe testing program is safe requires a judgmentof howsafe is safe enough. The subjective nature of this judgment is illustrated through the decision-making process HOW SAFEHASIT BEEN? of the Containment Evaluation Panel (CEP) which reviews andassesses the containment of each test.? The panel evaluates the probability of containmentusing the terms‘‘high confidence,”’ ‘adequate degree of confidence,’’ and ‘‘some Some insight into the safety of the nuclear testing program can be obtained by reviewing the containmentrecord. Releases ofradioactive material are categorized with terms that describe both the volume of material released and the conditionsof the release: ‘Currently, ali U.S. nuclear test explosions are conducted at the NevadaTest Site. 2The Containment Evaluation Panelis a group ofrepresentatives from various laboratories and technical consulting organizations who evaluate the proposed containment plan for each test without regard to cost or other outside considerations (see ch. 2 for a complete discussion).