At the unit 5, in order to conduct in-core inspections, fuel
assemblies were transferred from the reactor core to the spent fuel
pool, from Nov. 3rd to Nov. 13th. On Nov 11th,the annunciator
sounded, indicating a high load on the refueling machine and its
automatic operation stopped. (Announced on Nov.12th)
Transfer of fuel assemblies except for that in question had been
completed on Nov. 13th and visual inspections of the fuel assembly
via an underwater camera was conducted today. At 10:45 am, we found
that the fuel assembly and its fuel support were misaligned.
No damage in the fuel in the reactor is presumed since there is no
visual abnormality such as deformation on either the fuel assembly
or the fuel support in question and there is no significant change
in the iodine concentration in the reactor water.
We suppose that the fuel assembly was misaligned from its fuel
support at the Earthquake because it somehow had not been loaded at
the right position at the last regular outage.
We will transfer the fuel assembly to the spent fuel pool and conduct
visual inspections of the assembly and its fuel support, measurement
of the channel box bend, and investigate the cause of the
misalignment.
In consideration of this event, we will take corrective actions such
as checking the vertical position of fuel assemblies during fuel
loading.
|