@chetlaham "Which is all peanuts in comparison to the overall longevity and the large number of components that do not need replacement or those that require relatively cheap overhauls."
As I have stated, any maintenance or contract work in a nuke plant is a magnitude greater than that of a thermal plant purely because of the regulatory requirement of a nuke facility over a thermal one. I dont think you have any clue the level of maintenance, or the costs, for a power plant of any kind. None of it is "cheap". Its huge huge huge work. A thermal plant planned outage can last 6+ weeks for a 250MW unit. Thats not "cheap".
"Also, explain how a coal plant is simpler than a nuclear plant? The absence is pulverizes and scrubbers is a good start."
I can't believe I am going to get in to an argument with someone who claims nuclear plants are simpler than a coal fired one. Especially considering you think you've "got me" by mentioning the fuel handling and emissions controls systems... But here we go.
In terms of knowledge industry wide, thermal generation has an abundance. Nuclear knowledge is few and far between, and expensive.
The number of people who can fix a thermal plant is a lot greater than that of a nuke one. The ones who can fix a nuke plant aren't cheap.
Water treatment requirements of a nuclear plant significantly overshadow that of a thermal facility. In a closed loop PWR, the reactor coolant requires expensive chemicals that are not effected by the fission process. The fission reaction can create undesirable water chemistry such as excess O2, so excess hydrogen must be maintained. Reactor loops require the use of a high purity stainless as fission, again, can pull impurities out of the stainless.
Chemists for water treatment in a thermal plant are easy to find. Chemists for nuclear are not, and when you do theyre expensive.
There is only one water loop to control the chemistry for at a thermal plant. In a nuke facility, there is at least three. All requiring their own unique chemicals that are impervious to the effects of fission.
There containment building for the reactor is complex.
There are only a handful or people who can operate these reactors, with the cert process being five times as long as the one required for a thermal plant.
Spent fuel pools and the spent fuel system is an art form. It must be monitored, cooled, and maintained.
Every single nuke worker is monitored health wise multiple times a year. Blood work, scans, check ups. Dosimeters worn at all times. Exposure limits tracked.
The emergency preparedness and emergency scenarios are probably twice that of my refinery. And refineries are pretty toxic, deadly, and explosive neighbours.
There are environmental and radiation monitoring systems at various radius distances away from nuke plants which thermal plants do not have.
The controls system for a reactor is about three times as complex. In a thermal plant, MW output is cascaded by loading the generator, which loads the turbine, which lowers the water level and pressure in the steam drum, which increases feedwater flow and increases firing rate, which increases fuel flow, which speeds up the pulverizers. For a reactor, MW output is cascaded by loading the generator, which loads the turbine, which loads the steam generating loop, which loads the steam generators, which lowers the water level and pressure of the SGs, which increases the pump loop speed of the SG, which increases water flow to the SG, which causes the pressurizer in the reactor to drop press, which causes the heat load in the reactor side of the SG to drop, which causes the reactor coolant pumps to speed up, which causes the reactor temp and pressure to drop, which causes the control rods to be manipulated. Nuke plants have almost three times the cascading control systems.
A nuke plants turbine is mostly that of a low pressure (LP) style, which requires a lot more care to make sure the steam entering the turbine is still superheated and absent of wetness. LP turbines by nature are way easier to make saturated steam due to the rapid pressure drop.
Nuke plants typically have, at the 1000MW unit mark, three to four LP sections, which means three to four times the steam controls compared to a thermal plant since a thermal unit has one steam inlet control system for the whole turbine.
The Safety Instrumented System, or SIS, that independently oversees the operation of any plant, is way more complex in a nuke plant. For a thermal plant, the SIS just has to trip the fire and thats it. Runaway states in thermal plants are easily controlled and very rare. By design, a runaway condition is next to impossible. Once the steam valve shuts on the boiler and the fire is off, the problem is over. However, in a nuke plant, the SIS has to monitor three times as many control parameters, and not only that, still has to control once it causes a trip. Even in a tripped state, a reactor can still runaway, and the SIS system has to prevent that. A thermal plant is either on or off. A nuclear plant has multiple laid up states, for example in refining we call one laid up state safe park. The plant isnt off, but it isnt on either. It can still runaway and still blow up. And this state still requires operation, oversight, and intervention. And still has an SIS intervention.
Fuel handling in a nuke plant is either complex, or insane. They either have to go to a reduced rate or be shut down all together to refuel.
Shutting down a nuclear unit to an off state takes weeks. A 250MW thermal plant is less than an hour.
Starting up a nuclear plant takes weeks. A 250MW thermal plant is roughly twelve hours from light off to synced to the grid.
The heat mass in a nuclear reactor, or warming rate, overshadows thermal plants. At roughly 30C an hour heating rate, the amount of pipes and vessels handcuffed to that rate is nothing in a thermal plant, and thats not even taking the turbines heat loading rate in to consideration. This is just the steam generating side.
Nuclear plants also like steady state power demands. Any major change in the demand by either reduction or increase can upset the reactor for hours. They do not like change at all. A thermal plant can meet a demand change within ten minutes.
Shall I continue?
