How are high levels of radioactive water getting out of the Fukushima 1, 2, and 3 Containment Buildings?
Fairewinds believes that even if the nuclear reactors have not melted down, radioactively contaminated water is leaking out of the reactors and containment buildings. Boiling Water Reactors (BWR’s), like Fukushima, have dozens of holes in the bottom of the nuclear reactor because BWR control rods enter the reactor from the bottom, unlike Pressurized Water Reactors (PWR’s) where the control rods enter from the top.
In the adjacent diagram, you will be able to follow a path as Fairewinds describes how highly radioactive water may be leaking directly into the environment. First, you note that each control rod has a control rod drive mechanism (CRDM) that uses graphite seals to keep the water inside the reactor (see highlights).
Unfortunately, at temperatures above 350F, these graphite seals quickly degrade. During reactor operation, constant cooling water flow is provided to each control rod drive mechanism to cool the seals. However, when the accident at Fukushima occurred, cooling stopped and the temperatures rose significantly past 350F causing a break down in each control rod mechanism seal. Since it is likely that rubble from the broken fuel rods has migrated and is collecting at the bottom of the reactor, the seals are being damaged by high temperature and/or high radiation. As the seals fail, the reactor coolant (assuming there is any left) will begin to leak out through the many small pipes marked in red.
The pipes marked in red are outside the primary containment system and located in the secondary containment building that was destroyed by explosions. Radioactive reactor water will bypass the containment, enter other buildings on site, and possibly directly into the ground water and the ocean due to the failure of the pipes [marked in red] that were destroyed by the explosion. The site has a history of drains and piping that has previously malfunctioned. In such a scenario, radioactive water would leave the containment on its own through other paths rather than burning through the vessel itself. Such a scenario also explains how such highly radioactive water migrated from the containment building to the adjacent turbine building where it contaminated workers by severely burning their feet.