Description of occurrence (edited from investigation report)

Radiological Assessor Training

DOE-HDBK-1141-2001

Student's Guide

III. Description of occurrence (edited from investigation

report)

A. Incident

The layout of the buildings and equipment at this

site are included.

Two employees at the Paducah Gaseous Diffusion

Plant (PGDP) received skin and clothing

contamination from Thorium-234 (234Th) and

Protactinium 234m (234mPa) while disconnecting a

used uranium hexafluoride (UF6) cylinder at the

C-337-A building, UF6 Feed Vaporization Facility, on

August 23, 1991.

B. Scenario of events

Starting at shift change, 12 employees, one of them

a Health Physics Technician, found contamination

on shoes and clothing. The incident was initially

identified during routine monitoring of the C-337-A

facility by a Health Physics Technician at 0900 (two

hours after the shift change). Efforts were initiated

by Health Physics to survey the area, identify the

source, and control the spread of contamination.

Surveys indicated widespread contamination in both

radiological and nonradiological areas of C-337

(adjacent to C-337-A) and C-337-A.

At some unspecified time, a critique was conducted

by the Assistant Shift Superintendent and all

personnel involved in the accident were interviewed.

All personnel who had been in the facility on the day

shift were contacted and surveyed. One individual

was found to have contaminated shoes and skin

contamination on the elbow and was taken to a

change house in C-337 for decontamination. Later

this employee's personal clothing was also found to

be contaminated, and through further investigation it

was learned that this contamination occurred in the

change house. A thorough survey was conducted in

the change house, and it was discovered that, in

addition to a few articles in the change house itself,

Module 16 - 2