3.5 Summary of Week 3

Figure 13

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This is a photograph of three people wearing protective clothing .

Figure 13

The nuclear incidents that you examined this week were the result of reactors going into meltdown.

In the case of Chernobyl, an error with the control rods led to the fuel rods going supercritical. The accidents at Three Mile Island and Fukushima were both due to failures in the coolant circulating.

At Fukushima, the reactors were shut down satisfactorily after an earthquake but a tsunami then flooded the building and this was the primary reason for the coolant failure. Meltdown and hydrogen explosions followed which led to radioactive fission products contaminating the surrounding area.

The containment of the reactors at both the Fukushima plant and Chernobyl is an ongoing problem and the decommissioning of the reactors themselves cannot happen for decades.

Next week, you will consider the environmental issues that surround the need to limit our use of fossil fuels. You will look at the design of the new nuclear reactor, being built at Hinkley Point, which has taken the events at Fukushima into account. You will also look at new developments including the use of thorium as a fuel and the pursuit of nuclear fusion.

You can now go to Week 4 [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] .