Effort was in progress at the plant to remove from the spent fuel pool (SFP) and transport to the radwaste repository a piece of fuel assembly (FA) cask with fuel fragments detected 31.01.91 while performing scheduled activity to reload spent FAs from SFP-3 to SFP-1.
The above piece of cask was placed in a specially manufactured container which was installed on a special vehicle (truck). During vehicle movement in the transport corridor (tunnel) the container struck the pipe located in the upper section of the corridor and fell overboard remaining retained by the safety cable. In this position it was transported to the repository. This resulted in the radioactive contamination of the transport corridor surfaces and of the road on the plant territory, which the special vehicle took. The following radiation situation was observed:
Gamma doserate in the transport corridor ranged from 1.5 to 2300 microR/s 0.1 m above the floor. The total area of contamination was 100m2.
Gamma doserate on the way from the transport corridor to the repository was 0.6-0.7 microR/s 0.1 m above the ground with the spotlike nature of contamination.
To prevent contamination scattering on the plant territory all the road from the transport corridor exit and to the entrance to the dry & liquid waste repository was covered with a layer of bitumen. Two sections of the road with the total area of 100 m2 were covered with a layer of concrete 15 cm thick. On completion of decontamination radiation situation at the plant became normal. The cause of contamination was violation of radiation safety regulations committed by plant personnel.
BASIS FOR RATING: Radioactive water spillage on the plant territory
DIFFICULTIES IN RATING:
Event date: Wed, 10-07-1991