The UK’s first SMR project looks to be a four-pack of AP300s. Why build four small reactors over one big AP1000? Let’s explain with a delicious metaphor
Let old Salty tell you lubbers why four is better than one. Many years ago now, I was a Propulsion Plant Watch Officer in the biggest nuclear power complex in the world. Then, and maybe still today.: USS Enterprise sported eight (count 'em, eight) nuclear reactors. Four screws (26-foot diameter propellers, for all ye landlubbers). Longest shaft at over 400 feet. Over 1,000 feet long at the waterline. Four acres of flight deck. Displacing 100,000 tons (Not weighing, landlubbers—a ship only weighs her anchor).
I can't tell you many more details, because, although the ship was built in the 1950s and much of the technology has advanced since then, if I told you I 'd have to shoot you. We were getting ready to get underway (that means, untie from the dock, lubbers), and I had the only reactor out of all those eight that was critical. Why? (You don't want me to have to shoot you, remember?)
But time and tide wait for no man, and US Navy ships--and HM's ships, I'll grant--have a penchant for meeting their schedules, especially when people are getting their cameras ready for when we sail under the Golden Gate Bridge on a bright and beautiful morning.
So for various reasons that some of my shipmates might recall, I was in charge of the only reactor out of the eight that was making steam, and we were due to get underway that morning at (time classified, even if I could remember after all these years). Four or five thousand men--not to mention Captain A—, who I'm sure, did NOT want to put his career at risk by not having the last line cast off at the assigned minute--were waving Goodbye to their wives, children, loved ones, and mine was the only reactor making steam. Well, if you haven't guessed, Yes, we did get underway on time. One reactor supplied all the steam to propel that mighty ship through San Francisco Bay, rolling as we passed under the Golden Gate Bridge so as not to scrape it, and out into the beautiful, deep blue Pacific Ocean.
And that, landlubbers, is what is called redundancy, and why four SMRs might just be right for that place, wherever it is in the UK. Even though I'm into wind turbines today, I'll take on any bloke in any pub who can't see an upside to nuclear.
The reactor pressure vessel may be much easier to fabricate in the 1/4 smaller size AP300 version. Sheffield Forgemasters has demonstrated the ability to use electron beam welding of forged ring-shaped subsections of such vessels. Much faster and much cheaper. This might also apply to steam generators and pressurizers. Pancake analogy? If the large size was as big as a "truck steering wheel" necessitating the use of a griddle that covered the whole stove top. Difficult, that.
I’m very taken by the “we need all shapes and sizes” argument. Too much of these conversations have been shortcutting to maximizing economic efficiency and lowering cost, forgetting about the learning that happens as part of that journey.
If we get to a society where even the smallest developing country needs a 4 pack of AP1000s to power their growing economy then we will know we have won. Until then we probably need a bunch of shapes and sizes…
Let old Salty tell you lubbers why four is better than one. Many years ago now, I was a Propulsion Plant Watch Officer in the biggest nuclear power complex in the world. Then, and maybe still today.: USS Enterprise sported eight (count 'em, eight) nuclear reactors. Four screws (26-foot diameter propellers, for all ye landlubbers). Longest shaft at over 400 feet. Over 1,000 feet long at the waterline. Four acres of flight deck. Displacing 100,000 tons (Not weighing, landlubbers—a ship only weighs her anchor).
I can't tell you many more details, because, although the ship was built in the 1950s and much of the technology has advanced since then, if I told you I 'd have to shoot you. We were getting ready to get underway (that means, untie from the dock, lubbers), and I had the only reactor out of all those eight that was critical. Why? (You don't want me to have to shoot you, remember?)
But time and tide wait for no man, and US Navy ships--and HM's ships, I'll grant--have a penchant for meeting their schedules, especially when people are getting their cameras ready for when we sail under the Golden Gate Bridge on a bright and beautiful morning.
So for various reasons that some of my shipmates might recall, I was in charge of the only reactor out of the eight that was making steam, and we were due to get underway that morning at (time classified, even if I could remember after all these years). Four or five thousand men--not to mention Captain A—, who I'm sure, did NOT want to put his career at risk by not having the last line cast off at the assigned minute--were waving Goodbye to their wives, children, loved ones, and mine was the only reactor making steam. Well, if you haven't guessed, Yes, we did get underway on time. One reactor supplied all the steam to propel that mighty ship through San Francisco Bay, rolling as we passed under the Golden Gate Bridge so as not to scrape it, and out into the beautiful, deep blue Pacific Ocean.
And that, landlubbers, is what is called redundancy, and why four SMRs might just be right for that place, wherever it is in the UK. Even though I'm into wind turbines today, I'll take on any bloke in any pub who can't see an upside to nuclear.
The reactor pressure vessel may be much easier to fabricate in the 1/4 smaller size AP300 version. Sheffield Forgemasters has demonstrated the ability to use electron beam welding of forged ring-shaped subsections of such vessels. Much faster and much cheaper. This might also apply to steam generators and pressurizers. Pancake analogy? If the large size was as big as a "truck steering wheel" necessitating the use of a griddle that covered the whole stove top. Difficult, that.
Good analysis! The optionality of a 4 stack alone could be very valuable.
I’m very taken by the “we need all shapes and sizes” argument. Too much of these conversations have been shortcutting to maximizing economic efficiency and lowering cost, forgetting about the learning that happens as part of that journey.
If we get to a society where even the smallest developing country needs a 4 pack of AP1000s to power their growing economy then we will know we have won. Until then we probably need a bunch of shapes and sizes…