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Computer wiring tunnel, abandoned coal power plant. Photo by Bryan Buckley. (lemmy.world)
submitted 9 months ago by to c/pics@lemmy.world
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[–] 7 points 9 months ago* (1 child)

Um, I mean the boiler(s) itself are a small part of it. It's all the other stuff. I am not a coal expert by any stretch, but if you think of the signals required just to convey coal, probably dozens or more of drives with run/stop/various errors/temperature/current/voltage/perhaps VF, plus all the sensors you need to use motors like that with (presumably bucket conveyors?) like slip, like explosion disk detection from dust. Not like all of those have to be present, but every step has so many signals.

Plus then you've got a steam turbine and a switchyard, plus all the plant utilities like process heating and cooling water, compressed air, steam turbine makeup water, etc

Nowadays you do IO to remote racks that are close to devices (like valves/motors/etc) then use Ethernet to make it go further. Pre ethernet there were typically proprietary cables for the same, but thankfully that's a thing of the past

But something like I mentioned with a motor drive having all those signals, yeah it's typically just an Ethernet cable + power + estop (usually hardwired still). So maybe 40-50 wires down to 5-8

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  • [–] 4 points 9 months ago* (last edited 9 months ago)

    Whether its a power boiler or a recovery boiler there are a huge number of sensors and actuators needed to monitor and adjust. Just the pressure systems at the various points inside the boiler tubes. Required miles and miles of copper cable. There is also a huge number sensors and actuators in the fire box from the fuel feed to the exhaust and anti pollution systems.

    Then you move on to the turbine section and you have more wiring for that.

    I once saw the aftermath of a single oil sensor failing and not going to zero. It hung and didn't alarm. The the babbit bearings on the turbine side seized. The whole place nearly melted down until the engineer on site managed to get the boiler shutdown with very minimal damage to the boiler. They fired him the next day for the maintenance miss and they had to rebuild the whole turbine because the blades got wet.

    Power boilers if they lose water they will melt from the hanger to bottom. I've seen the aftermath of that as well. So the old legacy stuff is here to stay until it stops working.

    Nukes were that times ten. Multiple sensors for any given system plus stand by emergency systems all leading to control room. Inside the containment vessel there are cable trays everywhere on every level. The support equipment outside the containment vessel were no different. It is unlikely most of that will can ever be replaced. Many of these systems take a decade or more to slights retrofit because with a nuke you can't really make a mistake.

    I sat in on multiple meetings because a pump housing mounting bolts were supposed to be left handed threads but were right handed instead. It took them over a week to decide if it was okay that way. Engineering office guys were trying really hard to not to have to submit all the paperwork to get the prints changed after nearly twenty years in service. It would have been very costly in time and materials to remove the studs in the floor and replace and repour the floor section so they kept the right handed threads. This should give you some idea how hesitant they are to change anything in a nuke. I can only hope in the nearly thirty years since I did those kinds of shutdowns they have replaced some of it.

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