Hunterston B, shut down, permanently.

[adam2]

One reactor at Hunterston B "moved to defueling phase, will not resume power generation" This is I think a little earlier than the forecast closure date of 2022.
Whilst the loss of generating capacity is a cause for concern, I find the closure to be re-assuring, rather than "crossing fingers and pressing on regardless" until something breaks.

The other rector is still running.

The above was true WHEN POSTED but the other reactor has now closed, see later posts for details.
I have edited the thread title to reflect this.

[kenneal - lagger]

I would worry that a fault in one reactor serious enough to warrant its closure might be present in the other, supposedly identical, still running reactor.

[clv101]

Cracks are related to use, would need to check the hours of each, one may have a many thousand more hours than the other.

[adam2]

Presuming that the problem is the cracks in graphite blocks that form the core, then these cracks or of little consequence normally.
The risk is that an earthquake could distort the core, prevent the insertion of the control rods, and perhaps prevent a shutdown. Earthquakes are very rare, but could happen.

It is of course possible that something else has broken.

[Potemkin Villager]

I would worry that a fault in one reactor serious enough to warrant its closure might be present in the other, supposedly identical, still running reactor.

One thing, that I think can be said with some degree of certainty, is that all the reactors of the same notional design,
in a sense are succession of prototypes each incorporating significant modifications and "improvements".

[Potemkin Villager]

It is of course possible that something else has broken.

But of course we will never know because it is an official secret!

[adam2]

I doubt that the failure of some other part of a nuclear power station would be that secret.

If, for example, the steam turbine or the alternator has broken, then under other circumstances the failed part would be mended or renewed. However in this case of a nuclear reactor with a very limited future life, spending money would not be justified and closure be slightly brought forward instead.

[clv101]

Hunterston B closes for good today:

https://www.theguardian.com/business/20 ... in-service

Lasted 46 years, 20 more than original design. -965MW.
Hinkley Point B is the a matching power station, closes this July. -965MW.