64 © The Containment of Underground Nuclear Explosions a prompt venting. Baneberry vented through a fissure and decaying radioactive material was pumped out over many hours. Baneberry released Figure 4-4—Yileld v. Distance 1,000 = more curies than Pike; however, due to its slower release, a higher percentage of the Baneberry material was in the form of noble gases, which are not deposited. The data suggest that much less than 7 percent of the released material was deposited.!° Therefore, it is thought that Pike is actually a more 500 mR exposure 170 mR 100 E~ SF Thesensitivity of the Pike model can be judged by looking at the degree to which its predictions are affected by the amount of material released. For example, consider a test in which 10 percent of the radioactive material produced by the explosion is accidentally released into the atmosphere; in other words, 10 percent of the material that would have been released if the explosion had been detonated aboveground. This also roughly correspondsto the amount of material that would be released if the explosion had been detonated underground at the bottom of an open (unstemmed)hole. The 10 percent release can therefore be used as a rough approximation for the worst case release from an underground test. To evaluate the adequacy of the Pike model predictions to withstand the full range of uncertainty of an accidental release, the question is: what effect would a release of 10 percent rather than, say 1 percent, have on the location of 170-mR and 500-mR exposure lines? As figure 4-4 illustrates, changing the yield of an explosion by an order of magnitude (in other words, increasing the release from say 1 percent to 10 percent) increases the distance of the 170-mR and 500-mR lines by roughly a factor of 2. Therefore. assuming a worst case scenario of a 10 percent prompt massive venting (as opposed to the more probable scenario of around a | percent prompt massive venting), the distance of the exposure levels along the predicted fallout lines would only increase by a multiple of2. The Pike model therefore provides a prediction that is at least within a factor of about 2 of almost any possible worst-case scenario. So Any release of radioactive material is publicly announcedif the release occurs during, or immediately following,a test. If a late-time seep occurs, the release will be announcedif it is predicted that the exposure a conservative model than Baneberry. ACCIDENT NOTIFICATION Total 1st year Total tst year . a bm Lk 3 fr 10 F 0 0 1 Poe potorre tori r terrae papa 50 100 150 Distance (miles) Constant Pike Parameters Variable Wind speed = 15mph Yield * Pike Vertical wind shear = 20° Cloud rise = §,000ft Yield (in kilotons) v. distance (in miles) for projected fallout using the Pike Model. TYE indicatestotal first year exposure Increasing the yield by a factor of 10 roughly doubles the downwind distance of the projected fallout pattern. SOURCE: Provided by National Oceanic and Atmospheric Admristration National Weather Service Nuclear Support Office +988 radioactive material will be detected outside the boundariesofthe test site. If no detection off-site is predicted, the release may not be announced. Operational releases that are considered routine (such as small releases from drill-back operations) are similarly announced only if it is estimated that they will be detected off-site. The Environmental Protection Agency is present at every test and is therefore immediately aware of any promptrelease. The Environmental Protection Agency, however, is not present at post-test drillback operations. [n the case of Jate-time releases or operational releases, the Environmental Protection Agency depends on notification from the Department of Energy and on detection of the release (once ‘OBaneberry, however, had a limited data set of usable radioactive readings.