2.1.1 Narrative
RADIOACTIVE MATERIALS ASSESSMENT
OSC Huyser returned to the Site with START and EPA Environmental Response Team on June 21 and June 22 to assess and decontaminate one room in the North Building which was found to contain radiological materials. Entries were made in level C PPE with dry decontamination. Air sampling was conducted inside the room, outside the room, and outside the building.
A total of fifteen containers were found which contained or were believed to be contaminated with radioactive source materials; most containers were glass jars of approximately 250mL in size. Six containers were labeled as Thorium Nitrate, two containers were labeled as Thorium Oxide, and seven containers were illegible or unlabeled. The containers were packed with vermiculite in 5-gal buckets. Debris from the contaminated room was packed in three trash bags. Screening of the room surfaces as well as floors and containers throughout the building was completed with alpha particle detection equipment based on the prevalence of Thorium found. Screening throughout the north and west buildings was additionally conducted with gamma detection equipment. No other radioactive materials or contamination was identified at the Site.
Spilled liquid from one of the Thorium Nitrate jars was found in the concrete of the room over a small area of several square feet. Recommended remediation procedure was to use a concrete scabbler to remove the surface of the concrete with low dust generation and vacuum with a shop vac equipped with a HEPA filter. No concrete scabbler could be found. An electric demolition hammer with a wide flat head was used to scabble the surface of the concrete at incremental depths of 1/8 inch; concurrently a vacuum with a HEPA filter was used to remove disturbed material and dust from the impact area. Approximately nine square feet of concrete was cleared at a depth of 1/8" with one area approximately 0.5 square feet excavated to a depth of 3/4 inches. The floor was screened and found to be successfully decontaminated. Vacuum filters were discarded in a fourth trash bag. All overpacked and bagged radioactive waste was staged back in the room at the corner of the north building.
OSC Huyser returned on August 10 with MSDEQ to collect activity and isotope data from the containers and trash bags which was requested in order to solicit bids for disposal. Gamma dose rates from the containers ranged from 120 µR/hr to 1550 µR/hr at a distance of 1 inch but consistently descended by an order of magnitude at 12 inches. Three containers presented no significant dose above background when measured. Thorium-232 was identified near or above 80% confidence in 13 of the 15 containers with no match found in the other two. Count rates were measured for each container and trash bag as well. The data was recorded and submitted with solicitations for waste disposal bids.
HAZARD CATEGORIZATION AND SAMPLING
OSC Huyser and Kemron returned to the Site from June 27 to July 1 to complete hazard categorization and sampling of waste materials. Approximately 120 samples required hazard categorization analysis and several drums had to be re-sampled to obtain sufficient material volume for laboratory analysis. OSC Huyser also generated an inventory map to document the location of each numbered container.
Samples from drums and totes were bulked, according to waste stream, in groups generally not exceeding twenty units. 21 samples were sent off-site for laboratory waste characterization analysis, representing 15 potential waste streams.
2.1.2 Response Actions to Date
- All wastes in the north and west buildings have been stabilized
- >370 haz cat samples have been completed
- An estimated 38 lbs of elemental mercury have been shipped for disposal
- Elemental mercury wastes has been shipped off for transportation and disposal
- Activities in the west building are nearly complete
- Cleared debris from north building
- Cleaned sumps in north building
- Staged drums in north building
- Delineated extent of spilled mercury contamination
- Completed cataloging containers & sampling
containers onsite
- Completed cataloging containers & sampling
containers in west building
- Cleared debris from west building
- Completed staging catalogued and sampled drums and
totes in west building
- Completed removal of wastewater from secondary
containment area
- Completed pumping, removal and staging of wastes in the
tank farm
- Completed decontaminating mercury-contaminated area
- Completed removal and decontamination of
mercury-contaminated drums
- Completed hazard categorization
- Completed sludge removal from secondary containment
area
- Completed removing piping from tank farm
- Completed characterization and decontamination of radiological waste materials
- Completed sampling for waste disposal analysis
2.1.2.1 Current Container Count
Location |
Count (=>5 gal) |
Complete? |
North Building |
71 |
Yes |
West Building |
320 |
Yes |
Tank Farm (moved to north building) |
38 |
Yes |
Outside (moved to north or west building) |
153 |
Yes |
2.1.3 Enforcement Activities, Identity of Potentially Responsible Parties (PRPs)
The former partner declared that there were no available funds associated with the business to conduct the response and there were no other fund sources to undertake the action. Written access to conduct the response was not granted until May 18.
2.1.4 Progress Metrics
Waste Stream |
Medium |
Quantity |
Manifest # |
Treatment |
Disposal |
Petroleum Contact Water |
Secondary Containment Area |
5025 gal
|
1605647-01
|
Liquid Environmental Solutions |
Treatment |
Petroleum Contact Water |
Secondary Containment Area |
4735 gal |
1605647-02 |
Liquid Environmental Solutions |
Treatment |
Mercury |
Elemental |
38 lbs est |
007664748 FLE |
Overpack |
Reclamation |
|