On the monthly report of December, Tepco stated they measured 1.7E-07 Bq/cm3 of Sb-125 from the sample taken AM9:29~9:59 ,12/6/2011
It was from the air above the sea, 2~3km offshore.
Sb-125 is made when Sn, a material of zircaloy fuel cladding, is hit by neutron ray from the fuel.
It is not known where the fuel is but still there is a possibility that it emits neutron ray actively.
Sb-125 is constantly reported on the past monthly reports too.
Iori Mochizuki