The Energy Department’s Idaho National Laboratory suspended transuranic waste shipments to the Waste Isolation Pilot Plant (WIPP) in New Mexico immediately after an April 11 incident in which at least one 55-gallon drum of radioactive waste overheated and ejected its lid.
The suspension was precautionary, and shipments resumed on Tuesday, Idaho Site cleanup contractor Fluor Idaho said in a Wednesday press release. That happened only after confirmation WIPP had not received any of the same type of waste, according to the release.
The drum, believed to have come from the former Rocky Flats nuclear weapons site in Colorado, had not gone through the final waste characterization and certification process prior to shipment to WIPP, the contractor said.
In the five hours after the initial breached drum of repackaged sludge was discovered, it was determined “two additional drums experienced a similar drum failure,” according to an April 17 DOE occurrence report.
The contractor said at least one drum had been breached and further investigation is being conducted on other drums. Containers at the site from Rocky Flats were inspected April 12 and showed no signs of abnormal conditions, according to the Fluor Idaho statement.
Fluor Idaho has said the incident caused no injuries or environmental contamination.
The DOE report said three firefighters who responded to the smoldering drum showed no evidence in a follow-up medical exam of detectable radiation in their lungs. At the site, the fire crew had recorded some low-level alpha radioactive contamination on their hands.
Around 10:35 p.m. local time, the INL fire crew received an alarm from the Radioactive Waste Management Complex Accelerated Retrieval Project No. 5 (ARP 5) facility. ARP 5, which processes waste drums for eventual shipment out of Idaho, is described in the DOE document as a tent-like enclosure with a ventilation system monitored for radioactivity.
The breached drum or drums apparently remain in the ARP 5 area.
There were no workers at Airlock-5, where the drum breach occurred, at the time of the incident.
Upon entering the area, three INL firefighters smelled smoke, backed out of the facility, and each put on a self-contained breathing device before re-entering. They saw one drum with its lid off; no flames were evident but there was smoke coming from the top. They sprayed the drum with a fire extinguisher to stop the smoldering.
Digital scans of the drum indicated its external temperature was increasing. The firefighters left the area and then exited the building a few minutes after midnight. The ARP 5 area was determined to be stable around 1 a.m. April 12, according to the report.
An analysis team was established to determine the root causes and contributing causes to the drum breach.
Personnel with DOE and Fluor were expected to re-enter the facility on Thursday, Natalie Creed, hazardous waste unit manager for the Idaho Department of Environmental Quality said by email late Wednesday. The agency and its contractor met their requirement to inform the state within 24 hours and are expected to file a written report with the state within 15 days, she added.
“The April 11 event closely resembled scenarios that site emergency response personnel have been trained to respond to for many years,” Fluor Idaho said in its press release.
Idaho has been the leading waste shipper to WIPP since the facility resumed taking outside shipments in April 2017. About 54 of the 72 shipments received at WIPP during the first three months of 2018 have come from INL. The Energy Department is required to ship all transuranic waste at the lab out of the state by the end of 2018, but has acknowledged it might miss that deadline due to WIPP’s nearly three-year closure after a February 2014 radiation release.
Over the years, the ARP 5 facility has processed and repackaged about 9,500 drums of sludge-contaminated waste to remove liquids and prohibited items prior to shipment to WIPP for disposal, Fluor Idaho said.
Fluor Idaho has a five-year, $1.5 billion contract with DOE, which extends through May 2021 and includes risk reduction and protection of the Snake River Plain Aquifer.
The head of the Energy Department’s WIPP office in New Mexico on Thursday praised workers in Idaho for quick action in response to the exothermic event. “They are the ones who are quickly jumping on this,” Carlsbad Field Office Manager Todd Shrader said during a WIPP Town Hall event, which was webcast.
When asked, Shrader said the waste at issue could eventually be moved to WIPP after it is remediated and “made safe.”
After it was informed of the Idaho drum breach, WIPP double-checked waste recently arrived shipments at Carlsbad. The sludge waste already shipped from Idaho “has no oxidizers in it,” suggesting an exothermic event is unlikely, Shrader said: “It’s a completely different waste stream” than the breached drum at INL.
WIPP’s own waste characterization efforts has “barriers” built in, which would have flagged the potentially combustible drum before it could be shipped to New Mexico, Shrader said. As the disposal facility, WIPP has its own process in place to account for oxidizers and other potential problems, he noted.
