On Monday, Oct. 24, OPPD’s Fort Calhoun Station was taken offline for the final time. The reactor was tripped at 12:55 p.m. Hours later, the reactor core underwent a 36-hour chemical hold to reduce radiation dosage.
The chemical hold was completed early Wednesday morning and was a success.
“We got really good results with the chemical hold,” said Craig Longua, manager-Outage. “Our dosage rates were even lower than we predicted.”
After the chemical hold was completed, the reactor cooling system was cooled down, depressurized and vented.
Longua said the performance of the staff at FCS continues to impress in the face of difficult conditions.
“The station and staff have performed error-free, with no safety or human performance issues,” he said. “The attitude of the people around the plant continues to be very engaged. They are doing their jobs very well and continue to identify the issues we want them to be identifying. In that regard, it is similar to a refueling outage. The teamwork between the Outage Control Center and the people in the crafts has remained good, and everyone is doing their work efficiently and safely.”
Safety of the workers and community remains the highest priority for the crew at FCS.
A number of intricate tasks have been completed, such as work done on the power-operated relief valve, with more such tasks to come.
Defueling is set to begin Nov. 5, and will involve removing the reactor vessel head to remove the fuel for transfer to the spent fuel pool, where it will sit for five years.
After five years, that spent fuel will be stored on-site in concrete casks in an area west of the containment building. The storage area sits at a higher elevation – 1,011 feet above sea level – than does the containment building.
Another important safety measure to note is that the groundwater wells around the plant will continue to be monitored just as they always have. Those wells have been checked for radiation and contamination around the site since before the plant went online, and will continue to be checked on a quarterly and, for some of the wells, monthly basis.