Regarding Pu-238, and SNAP 9-A

[RONALD GOODWIN <RONALD_GOODWIN@health.ohio.gov>]

     In a recent thread, a discussion, or reference was made, regarding the 
     reentry of a SNAP reactor and the subsequent Pu-238 release and 
     dispersion across the stratosphere.  Merrill Eisenbud, in his book, 
     "Environmental Radioactivity ..." discusses the abortive reentry of 
     the SNAP 9-A satellite April 21, 1964.  This satellite failed to reach 
     orbital velocity and reentered the atmosphere at 150,000 ft. over the 
     Indian Ocean.  The power unit contained about 17,000 Ci of Pu-238.  
     The Pu was first detected at 108,000 feet four months following the 
     abort.  The stratospheric distribution of the debris during the next 
     several years followed the predictions that had been made on the basis 
     of transport models of ths stratosphere developed through studies of 
     the behavior of debris from weapons testing, however, the 
     concentrations of Pu-238 was lower in ground level air than had been 
     predicted.  About 95% of the Pu originally injected had been deposited 
     by the end of 1970.  Particle size analysis indicated that the 
     particle size ranged from 5 to 58 um.  The Pu content of ground level 
     air as monitored by de Bartoli and Gaglione (1969) et al, concludes 
     the 50 year commitment to the pulmonary lymph node from Pu exposure 
     between 1961 and 1968 was 36 mRem.  - source Eisenbud, p. 365-366, 
     "Environmental Radioactivity.