Work has stopped to dig up waste contaminated with plutonium at Hanford after two incidents earlier this month.
Problems related to the incidents included hazards not being adequately identified and responsibilities of workers not matching their training or qualifications, said Defense Nuclear Facilities Safety Board staff in a weekly report just released.
"Worker and management responses demonstrated a failure to implement lessons learned" from previous problems encountered by other Hanford contractors, the safety board report said.
CH2M Hill Plateau Remediation Co. has been digging up transuranic waste, typically waste contaminated with plutonium, that was temporarily buried after 1970. Then Congress said transuranic waste must be sent to a national repository, but until the Waste Isolation Pilot Plant in New Mexico opened, the waste was buried for later retrieval.
Much of the transuranic waste retrieved so far was in drums and boxes neatly stacked in holes dug in central Hanford and then covered with dirt.
But CH2M Hill has begun work on Trench 11, where the waste was dropped in helter-skelter.
On Feb. 1 an excavator with a bucket was being used to remove some dirt that had been piled up at the trench when it unexpectedly hit a glove box that was close to the surface of the ground.
The excavator bucket knocked the cover from one of the ports where gloves would once have been attached to reach into the glove box and do work with radioactively contaminated items. At first workers did not know that a glove box was hit and only knew that dirt was falling into a hole in the ground, which turned out to be the opening of the glove box.
They regrouped and took radiation surveys to determine it was a glove box, said Patrice McEahern, CH2M Hill vice president of safety, health, security and quality.
What had been categorized as a radiological buffer area became a high contamination area, the safety board report said.
Work resumed days later. The safety board representatives said work resumed before lessons learned from the incident were identified, but CH2M Hill disagreed.
On Feb. 4 there was another unusual event.
An excavator bucket hit and broke a buried pressurized container, resulting in two jets of odorous gas and soil, the defense board report said.
However, CH2M Hill said samples have been taken and there is no evidence that a pressurized container was hit. It does not know if there was a container in the soil or a pocket of gas.
The excavator operator stopped because he hit something and workers noticed the smell of propane, but the operator may have hit a rock, McEahern said.
The safety board reported that workers did not call 911 and did not request help from a hazardous materials team for two hours.
The response could have been better, but the incident did not meet emergency criteria that would require a 911 call, McEahern said. Workers did call the Hanford Fire Department to see if some of its equipment could be used, she said.
As a precaution, work was stopped to retrieve transuranic waste after the second incident, she said. Work on about five trenches was being planned or was under way.
CH2M Hill may continue to work through the issues raised for several weeks yet, including making sure it knows as much as possible about what to expect in the trenches.
Before work resumes, DOE wants a recovery plan and briefings to DOE managers on the issues, causes and corrections made to ensure safe operations, said a letter sent Friday from DOE to the contractor.
The halt to work came during a two-week review by a 23-member DOE team to verify CH2M Hill's Integrated Safety Management System. As a new contractor, it needed to have the system certified to guarantee it can perform work safely.
It had been working on the system for 18 months, including training 3,400 workers on the system and providing safety leadership training to 850 managers.
The verification team found that the safety system processes and procedures were "satisfactorily implemented at the company level," but not at the waste retrieval project, according to the DOE letter.
After CH2M Hill makes progress in making corrections, DOE will re-evaluate the safety system at its waste retrieval program, DOE said.