The Defense Nuclear Facilities Safety Board (DNFSB) is concerned about the age and reliability of the electrical system in a historic building still used for interim storage of radioactive sludge at the Energy Department’s Hanford Site in Washington state.
The board, in a July 2 report submitted to Energy Secretary Rick Perry, suggested installation of an alternate power feed and other steps to ensure the electric supply of the 1940s-vintage T Plant.
The T Plant site was where plutonium was processed for both the Trinity atomic bomb test in New Mexico and the second bomb dropped on Japan in 1945 to end World War II.
The facility is used today to hold radioactive sludge from the K West Reactor basin, until a treatment and disposal path are identified, said a DOE spokesman by email.
To date, workers have shipped 17 sludge transfer and storage containers to T Plant, and the remaining five containers should be there by the end of September, according to DOE. There will be roughly 35 cubic yards of sludge stored at T Plant when the shipments are complete.
The sludge is a mixture of tiny fuel corrosion particles, fuel rod and metal fragments, and soil and sand. The material is left over from decades of operation of the K-East and K-West reactors.
Much of the T Plant’s electric distribution system is original to the facility and well past its design life, according to the DNFSB. There is not a clear time line for how long the agency will continue to use at the facility, which is 800 feet long, 65 feet wide, and 80 feet high.
“Its age, combined with the lack of an alternate power supply, could impact the reliability of the safety significant confinement ventilation system” and its exhaust fans, the board said. The ventilation system ensures proper airflow within the building where the waste is being held.
Developing a backup power source, more preventive maintenance, and swapping out old equipment could shore up the infrastructure and extend the operating life of the facility, the board report says.
Without going into details, the Energy Department spokesman said a program has been devised to improve the reliability of the current electrical system at T Plant. Power system upgrades will be made as funding becomes available and, until then, a loss-of-power scenario has been analyzed to protect workers and the environment, he added.
The DNFSB is a health-and-safety watchdog for the Energy Department nuclear complex. Staff from the agency visited Hanford in May 2018 to review key electric infrastructure systems.
Along with improvements at the T Plant, the report endorsed installation of emergency lighting across Hanford that is more earthquake-resistant than the current setup, as well as regular inspections and maintenance for underground electric cables.
The emergency lightning at Hanford does not meet current building standards and could mean workers might have to evacuate without backup lighting in the event of a major earthquake, the DNFSB said.
Contractor Mission Support Alliance oversees infrastructure at the Hanford Site and it has started gathering life-cycle operating data on above-ground electric utility poles, the DNFSB noted.
In discussions with the board’s staff, MSA acknowledged the lack of an underground cable surveillance and maintenance program is a vulnerability. The vendor has not yet scheduled a program for regular replacement of underground cables.
The board noted the Hanford electric infrastructure has been upgraded in recent years and other planned improvements are scheduled. While not going into specifics, the DNFSB said planned projects should provide flexibility to Hanford’s operations.
“We appreciate the input from the Board and their recognition of significant progress and improvements that the Department has made to the electrical infrastructure on the Hanford Site,” said a DOE spokesman by email. The agency will consider the board’s input as it plans upcoming site projects, he added.
The board has no regulatory power over the agency, but it can make recommendations the energy secretary must accept or reject.
