Internal Exposure and Contamination During Pump Removal

Radiological Control Training for Supervisors

DOE-HDBK-1143-2001

Handouts

Internal Exposure and Contamination During Pump Removal

A work crew was assigned to rebuild a small pump in a non-radioactive system

located in an uncontaminated radiation area. In accordance with good ALARA

practices, the work plan called for removal of the pump to a shop area for the

repairs. The work supervisor and the Radiological Control Technician (RCT)

inspected and surveyed the pump area together to discuss the radiological

conditions and radiological controls necessary for the job. The small pump was

bolted to a metal mounting plate which was in turn bolted to anchors on a

concrete ledge. The plan was to remove the piping, unbolt the pump from the

mounting plate, have it surveyed for release, and carry it out to the shop. Since

the system was not radioactive, any contamination would be external. The RCT

surveyed all accessible areas of the pump and found no removable

contamination. He also used cotton swabs to check the area between the

bottom of the pump and the base plate. Again no removable contamination was

found. He allowed the job to proceed with no protective clothing on a routine

radiation area maintenance Radiation Work Permit.

When the crew tried to unbolt the pump from the base plate they found that some

of the bolts were rusty and could not be removed. They contacted the supervisor

and were given the okay to try the anchor bolts holding the base plate to the

concrete ledge. They removed the pump and base plate and exited the area.

Upon frisking out of the building, two of the workers were contaminated at

various locations on both skin and clothing. One worker had positive nasal

smears and the pump was contaminated. The highest levels of contamination

were on the underside of the base plate.

The room where the pump was located had been flooded with highly

contaminated water in an incident several years ago. All accessible areas of the

room were subsequently decontaminated to undetectable levels and routine

access without protective equipment had been restored.

Handouts 3