The electrical company EDF, which owns the Hunterston B power plant in Scottish County, about 40 kilometers (24 miles) from Glasgow, has released images and footage of cracks inside the graphite bricks of the reactors, which are mainly used to slow down neutrons and stabilize the reaction. Video footage inside one of the reactors at a nuclear power plant in Scotland has revealed more than 350 hairline cracks in the bricks, meaning it could become impossible to shut down in an emergency. Bricks are also used to channel the carbon dioxide used to cool the reaction. For this reason, they play an important role in securing the facility.
Cracks are expected to occur over time, and since the station was built in the 1970s, this is not surprising. Last year, anyway, the power company discovered that reactor 3’s reactor had 370 hairline cracks in about 3,000 bricks – a safety limit of 350% – so the reactor was removed from operation and did not generate electricity for a year. The limit set by the Nuclear Regulation Office (ONR) guarantees that the reactor can be safely shut down in an emergency.
Station director Colin Weir told the BBC, “We need to show that the reactor will always shut down and it will shut down in the event of an extreme earthquake.” “We have conducted one of our largest inspection campaigns on the reactor three, we have renewed our modeling, tested, and analyzed all the information we will submit to ONR to build our safety.
The EDF is planning to sue ONR that the operational limit should be increased to 700 cracks and then the reactor should be restarted. All 14 advanced gas-cooled reactors in the UK employ graphite bricks, so the decision to limit cracks in these reactors could affect larger power generation across the country. There is clearly a lot of interest in understanding in detail the limits of graphite and its protection.
“It is difficult to place a definite value on the number of fractions considered reasonable. Graphite is complex, and radioactive graphite is even more so this is why scientists have done so much research on this lately,” said Dr. Ben Britton told IFLScience. “Generally the limitations were based on very conservative assumptions and the EDF would have to make a strict technical case on behalf of the ONR to approve the changes in the limits.” The Hunterston B power plant provides a base-load of electricity sufficient to power 1.8 million homes and is expected to be operational by 2023, currently.