As many of the readers are aware, I travelled back to the Chernobyl nuclear power plant again in November, 2016. This year was even more powerful than our program in 2015. I am working on putting together a new series of editorials documenting the continuing remediation activities taking place in Chernobyl.
I am focusing this brief article on our visit to the central hall of the Unit 2 reactor and would like to share this video that I captured during our visit that has been narrated by my friend Carl Willis, a nuclear engineer from New Mexico.
The video begins as we are walking through the deaerator corridor, also known as the golden corridor, which is used by workers to access the control rooms, dosimetry, etc, and includes an interesting experience we had riding an old elevator.
The Unit 2 reactor is an RBMK reactor, very similar to the Unit 4 reactor that was destroyed in 1986. The Unit 2 reactor continued operating until a fire in the turbine building damaged critical safety equipment in 1991.
The reactor hall looms above the operating floor and contains a massive fuel handling machine that is used to transport fuel assemblies.
The RBMK reactor was designed to allow operators to swap out three to five fuel assemblies per day, while the reactor was operating, unlike US reactor designs which requires the reactor to be shut down for refueling. This also means that the Central Hall is a sort of radioactive hot cell during these refueling operations.
The RBMK reactor design incorporates over 1,700 fuel channels, each is individually pressurized, meaning each channel is its own kind of reactor.
In the spent fuel pools the power plant is storing stringers which were used to raise and lower components in and out of the reactor. Some of the stringers had localized surface contamination on them from being in the reactor during operation. The exposure rates near the surface of one of the stringers was around 2 roentgen per hour, but were barely detectable from more than a few feet away.
To put the measurements in perspective, normal background radiation rates in most of Ukraine are between 6-12 uR/hr (microroentgen). There are 1,000,000 microroentgen in a roentgen, but this is a localized surface contamination, not ambient exposure levels in the general area.
One of my favorite photos from Unit 2 is through the portal where operators could view fuel handling operations.
All of the reactor fuel has been removed from the reactor and the spent fuel pools and placed in the ISF-1 common storage facility until the ISF-2 facility is constructed and the assemblies can be placed in dry casks for storage.