This will be the BS 1363 plug and socket of the nuclear world.

Then the fuses will probably overheat the output terminals at full load....

flippancy aside

We are unusual but not unique in being a country that has actually had a home designed nuclear reactor failure that was very serious, and also a history of mainland terrorist bombings,  and that history casts a long shadow in terms of how we like to do stuff and what we like things to be failsafe against.

(would you prefer a Chernobyl design ? is the obvious counterpoint. It is fine if you have the space, we don't.)

Over-engineered, perhaps, but hopefully unconditionally safe.

Where we are getting into knots is the storage/disposal of waste that is low level enough we could probably stack it in the car park at the local supermarket and do no-one any harm, apart from the obvious loss of parking spaces.

Mike.

Thinking more, 7000 change requests initially sounds like a lot but may be quite reasonable on a big building programme - it rather depends what they are. Fitting UK sockets instead of French  ones may not be that hard to do after the fact, but changing foundation depths or wall thicknesses has to be agreed early on... Just normally we do not document it.

And perhaps the fact there has been almost zero design and build of reactors and supporting structure in the UK since the early 2000s, so the processes and expectations are those set by the AGR pioneers, now long retired makes us more cautious.

M.

I agree with the importance of safety, but the changes may not improve the safety and can actually reduce it. Is there really a need to increase the mass of the system by 1/4 , which I assume must be shielding? Have ridiculously low radiation levels been demanded?

The British design expertise was with gas cooled reactors which have a much lower core energy density and involve a different set of risks. A PWR is a rather different system with different safety requirements.  Is a control system based on AGR conditions likely to be a good basis for a PWR or is it just interference. The French have standardized on PWRs for many years and should have more relevant experience.

According to the Wikipedia page en.m.wikipedia.org/.../Sizewell_nuclear_power_stations the Westinghouse design was modified at Sizewell B to meet UK standards.

It would be interesting to know if this new design is more or less modified than Sizewell. 

I see that E+T is reporting the same problem:

'Challenges include thousands of design changes demanded by regulators, inflation, disruption to supply chains and labour shortages.'

Hinkley Point C delayed to 2029 at the earliest as budget increases substantially | Engineering and Technology Magazine (theiet.org)

Hi Roger,

This nuclear safety problem is worrying me as we know that nuclear submarines have sailors living for a whole year within metres of a nuclear reactor and seem to be unharmed??

Further, we read that uranium fuel rods can be safely stored under water in tanks on the power station site.

Someone needs to write a paper on why we need more reinforced concrete I think.

The water thing is quite fun, This article is a bit tongue in cheek but the figures referred to and used to make the calculations are  correct.

https://what-if.xkcd.com/29/

It implies we were not so easily scared we could save a lot of money on heating swimming pools by giving them a few dead fuel rods each in a keep-out cage at the bottom ;-)

Mike

This is a brief guide to radiation levels:

Ionising radiation: dose comparisons - GOV.UK (www.gov.uk)

As you are supposed to plan for a maximum exposure of 1/3 of the limit it would not be possible to build a nuclear power plant in Cornwall 

Yes, as I thought a totally unrealistic limit which needs revision to something workable but safe.  If nuclear subs use a sensible limit why not adopt that instead of spending/wasting billions in over specifications?

There are 2 issues here. Safety of personnel and nuclear safety. Personnel safety (mainly radiation dose) is readily achievable as evidenced by the simplified example of the swimming pool and nuclear submarines. Nuclear safety encompasses, for example, reactor containment and plant operation within safe parameters. Amongst others, the nuclear industry works to ALARA - as low as reasonably achievable, so the changes made now are likely to be safety enhancements to protect operators, maintainers and the public.