Question About Historical Criticality Accident

[dsimpson@unlnotes01.unl.edu]

One of the better known radiation accidents and early criticality fatality was
an  experiment that happened at Los Alamos in August 1945.  It has been depicted
(with great historical inaccuracies) in such movies as "Fat Man and Little Boy".
As an amateur historian of radiation accidents, I've always found it curious
that two different dates are given for this accident in various references.  For
example, Ron Knief's book on Nuclear Criticality Safety gives Aug 8, while
TID-5360, "A Review of Criticality Accidents" lists Aug 21.  I have seen several
other references as well, and there does not seem to be a clear consensus
between the two dates.
During a clean out of some old documents last week, I thought I had found a
reference that would clarify the date but it only added to the puzzle.  This was
a 1968 AEC document entitled "Operational Accidents and Radiation Exposure
Experience, 1943-1967".  In this document, a chart on page 13 lists the accident
as happening on Aug 21, while a description of the accident on page 33 lists the
date as Aug 8.
My interest in the exact date is related to other historical events that month.
The Aug 8 date would be in between the bombings of Hiroshima and Nagasaki, while
the later date would have been well after both bombings.  ("Fat Man and Little
Boy" has the event happening before either bombing, but then that's Hollywood.)
If anyone can clear this up and  give a definite date for this event, I would
appreciate it.  Note that simply referring to a review publication, especially
one from the last  30 years or so, probably doesn't solve the question, since
there was clearly some conflicting information prior to that time.

+++++++++++++++++++++++++++++++++++++++++
David R. Simpson, Ph.D., CHP
Radiation Safety Officer
University of Nebraska - Lincoln
dsimpson1@unl.edu
+++++++++++++++++++++++++++++++++++++++++


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