Description of occurrence (edited from investigation report) cont'd

Radiological Assessor Training

DOE-HDBK-1141-2001

Student's Guide

There was a portable fan temporarily positioned to

cool employees just north of the 5 West autoclave

control panel, inside the Contamination Zone. The

fan had only been in place a few weeks. It was

operating during the shift in question. Apparently no

one had questioned the use of this fan in the area

prior to the event. Circumstantial evidence places

one operator exiting from either the 4 West or 5

West autoclave in the path of this fan while trying to

remove a pigtail gasket. The area of highest surface

contamination was spread along a line from the fan

(located by 5 West autoclave), past the 4 West

autoclave to the 3 West autoclave control panel in

the direction that the fan blows.

Self-monitoring performed by the employees upon

exiting the Contamination Zone where the job was

performed was inadequate, in that the employees

did not recognize the contamination present on their

skin and/or clothing. The employees performed

their other duties during the remainder of the shift,

thereby spreading this contamination to both

radiological and nonradiological areas. This spread

of contamination to nonradiological areas through

failure to recognize personal contamination at exit

monitoring stations caused other personnel to

become contaminated when the shift change at

0700 on August 23, 1991, brought new personnel

into these areas.

Based on the interview with Employee No. 1, the

employee traveled to C-337 around 0400 for a

break. Upon exiting the vaporizer Contamination

Zone and going to the C-337-A Operation's

Monitoring Room, the Bicron frisker was indicating

high but not alarming due to high ambient

background radiation levels. The employee reset

the monitor and remonitored. The employee

indicated that the reading was elevated, but was not

alarmed this time. The employee stated this was

normal since the background in that area is often

high.

Module 16 - 6