Release of I-131 during TMI-2 accident.

[Andy Hull <hull@mail.sep.bnl.gov>]

Although I don't have the time at the moment to look for the exact details
of a paper I presented at the ANS sponsored 10Yr Post TMI session, I think
it is important insofar as it is relevant to the KI distribution issue to
distinguish between the amount of I-131 "released" from the fuel during the
accident and that which was released into the atmosphere during and shortly
after the accident.  

According to a report (EPRI) about 60% of the radioiiodines were released
from the melted and/or overheated fuel.  However, almost all of them ended
up in the thousands of gallons in the bottom of the containment building.
Only 15 Ci escaped during the first 15 days after the accident through a
filtered pathway from the let-down heat exchanger to the filtered vent of
the Auxiliary Building and another 15 days to the end of April 1979.  The
very small airborne concentrations and deposited I-131 found in the field
by DOE and other monitoring teams were consistent with these releases
conclusion.

On this basis I would suggest that effort and expenditures for stockpiling KI
in the neighborhood of nuclear reactors ought to be balanced by the
considerations of consequences times probability.  As long as there is any
water to act as an I sink, the release of large amounts of I during an
accident seems to me very small.  Also, my impression is that even for the
Chernobyl accident,
the principals I pathway was the ingestion of milk and not by inhalation, a
pathway controllable irregardless of the availability or non-availability
of KI.

Andrew P Hull
EHSS, Bldg 51
BNL
Upton NY  11973

Ph. 516-344-4210
Fax 516-344-3105
e-mail  hull@mail.sep.bnl.gov