Chapter tf Executive Summary The chances of 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 announcingalltests. 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 temperatures are 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 offission 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 prevent the 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 ma- terial from reaching the atmosphere), HOW SAFEIS SAFE ENOUGH? 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 whatis an acceptable level of risk. 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 who feel that testing is important for our national security will accept greaterrisk, 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 voluntary activities—suchas sky diving or smoking— maystill consider the much lower risks 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 of the Containment Evaluation Panel (CEP) which reviews and assesses the containment of testing program can be obtained by reviewing the containmentrecord. Releases ofradioactive containmentusingthe terms ‘‘high confidence,”’ ‘adequate degree of confidence,’’ and ‘‘some conditions of the release: each test.? The panel evaluates the probability of HOW SAFEHASIT BEEN? Someinsight into the safety of the nuclear material are categorized with terms that describe both the volume of material released and the ‘Currently, all U.S. nuclear test explosions are conducted at the Nevada Test Site. ?The Containment Evaluation Panel1s a group of representatives from various laboratories and technical consulting organizations whoevaluate the proposed containment plan for each test without regard to cost or other outside considerations (see ch. 2 for a complete discussion).