War in Ukraine

[Matt2496]

Don't you still need the cooling towers to vent the exhaust away?

Edit: TLDR, the heat can be removed through evaporation (cooling tower) like what you're alluding to (water vapor) or can be removed via convection (cooling pond).

Below is a diagram if you're interested. The third loop here goes from the condenser to the cooling tower/pond.

 

[NorthDallas40]

Edit: TLDR, the heat can be removed through evaporation (cooling tower) like what you're alluding to (water vapor) or can be removed via convection (cooling pond).

Below is a diagram if you're interested:

View attachment 666504

I’m not @AM64 but I’ll add that currently the reactor is idled and thus is not producing a major amount of heat. Thus the required cooling is minimal and as you’ve shown the layered and redundant systems designed for a reactor under load in this case they have significant capacity not being utilized. So one cooling tower loop down with all of the layered cooling isn’t a danger under current conditions. Still need to put the fire out and manage the cooling loop but no risk of a radiation release.

 

[Matt2496]

I’m not @AM64 but I’ll add that currently the reactor is idled and thus is not producing a major amount of heat. Thus the required cooling is minimal and as you’ve shown the layered and redundant systems designed for a reactor under load in this case they have significant capacity not being utilized. So one cooling tower loop down with all of the layered cooling isn’t a danger under current conditions. Still need to put the fire out and manage the cooling loop but no risk of a radiation release.

Yes, you are correct. They are currently shut down so the only heat being generated currently is decay heat from the nuclear decay of the fission products (Iodine-131, Caesium-137, Strontium-90 etc).

 

[NorthDallas40]

Yes, you are correct. They are currently shut down so the only heat being generated currently is decay heat from the nuclear decay of the fission products (Iodine-131, Caesium-137, Strontium-90 etc).

They aren’t poisoned right? They just have the control rods fully engaged right? The reactors can be brought back on line?

 

[Matt2496]

They aren’t poisoned right? They just have the control rods fully engaged right? The reactors can be brought back on line?

I'd have to ask a nuclear engineer for that info lol. I'm pretty sure the fuel assemblies get poisoned with Xenon-135 after being shutdown (control rods inserted) for a certain period of time, but when positive reactivity is inserted it can be overcome.

 

[NorthDallas40]

I'd have to ask a nuclear engineer for that info lol. I'm pretty sure the fuel assemblies get poisoned with Xenon-135 after being shutdown (control rods inserted) for a certain period of time, but when positive reactivity is inserted it can be overcome.

By poison I mean permanently shut down. I think the Navy refers to it as “scram” which is a non reversible process. I remember at one time the method was introducing large amounts of boron directly into the reaction chamber thus my usage of the term poison. Boron I’d guess is used in control rods also but in a removable fashion.

What I was asking in a way to try to sound cool is if you knew if they permanently disabled the reactors to where they could not be restarted or not.

ETA: so I googled SCRAM my usage of that term is not correct either. It just means to terminate the fission process but does not automatically imply a non reversible process.

 

[Matt2496]

By poison I mean permanently shut down. I think the Navy refers to it as “scram” which is a non reversible process. I remember at one time the method was introducing large amounts of boron directly into the reaction chamber thus my usage of the term poison. Boron is guess is used in control rods also but in a removable fashion.

What I was asking in a way to try to sound cool is if you knew if they permanently disabled the reactors to where they could not be restarted or not.

So a reactor SCRAM is just another term for reactor trip which is where all control rods insert. Dumping boron into the core would definitely permanently shut it down until it was cleaned out and the fuel assemblies replaced. The control rods I've come across were made out of a silver-indium-cadmium alloy.

 

[NorthDallas40]

So a reactor SCRAM is just another term for reactor trip which is where all control rods insert. Dumping boron into the core would definitely permanently shut it down until it was cleaned out and the fuel assemblies replaced. The control rods I've come across were made out of a silver-indium-cadmium alloy.

Yep I added an edit. I first heard that term by a retired submariner and I’m guessing he used it wrong or I heard it wrong I inferred it was a permanent shut down. Most definitely not the case.

 

[BeardedVol]

 

[MontyPython]

So a reactor SCRAM is just another term for reactor trip which is where all control rods insert. Dumping boron into the core would definitely permanently shut it down until it was cleaned out and the fuel assemblies replaced. The control rods I've come across were made out of a silver-indium-cadmium alloy.

Russians were burning tires in the cooling tower. That's all.

 

[KB5252]

Where is Kadyrov at currently? Haven't anything from or about him recently..... Though admittedly I haven't been following events in Ukraine that closely since enjoying was grinding down.

 

[evillawyer]

Where is Kadyrov at currently? Haven't anything from or about him recently..... Though admittedly I haven't been following events in Ukraine that closely since enjoying was grinding down.

Filming tik-toks of his lads being weekend Rambos shooting trees in the woods nowhere near the frontline?

 

[AM64]

By poison I mean permanently shut down. I think the Navy refers to it as “scram” which is a non reversible process. I remember at one time the method was introducing large amounts of boron directly into the reaction chamber thus my usage of the term poison. Boron I’d guess is used in control rods also but in a removable fashion.

What I was asking in a way to try to sound cool is if you knew if they permanently disabled the reactors to where they could not be restarted or not.

ETA: so I googled SCRAM my usage of that term is not correct either. It just means to terminate the fission process but does not automatically imply a non reversible process.

Reactivity (the ability to enable/continue the fission process) can be controlled by both control rods and using boron in the reactor coolant. There are plenty of different reactor types (even if you talk one type like PWRs - pressurized water reactors), so there is not necessarily one single operational strategy. Also naval reactors use highly enriched fuel, and US commercial reactors use low enriched fuel. As an example, a US commercial reactor will not be able to restart until radiation byproducts like Zenon decay; while a naval reactor with highly enriched fuel can overcome a "poison" like Zenon and restart immediately - at least that's my understanding on the naval reactors. SCRAM is generally considered the rapid insertion of control rods to immediately shut down a reactor - either military or commercial. Commercial reactors have different methods to move control rods - they may use roller nuts that screw the rods in/out or systems like old car bumper jacks (rod jacking). In either case the systems can be unclamped so the rods simply fall down into the core during a SCRAM. It's also a safety mechanism in case rod control power should be lost.

When a reactor is started up after refueling and the fuel is new, it's common to borate the water to help control reactivity. Boron can be inserted if necessary to reduce reactivity globally whereas individual control rods control locally. That really wasn't all my area of expertise. Some knowledge is from reactor theory in school and some was testing in plants when there were operating anomalies - such as flux tilt. We did neutron noise analysis to detect and monitor unusual neutron flux indicative of fuel movement (or even differential movement between fuel assemblies, incore neutron detectors, and control rods). The fuel assemblies themselves have have limited motion and they sit in a core barrel which also moves - excore detectors (outside the reactor) sense the movement - easiest way to visualize that would be a lightbulb hanging by a wire and a light meters sensing the change in intensity as the bulb swings nearer and farther. By Fourier analysis of the amplified incore and excore detector signals (DC level blocked) can detect motion, preferential directions, and trends.

When a reactor is shut down, it still produces a lot of heat - a little like turning off a burner on a normal electric stove. With a reactor it's both due to retained heat in the fuel and the fact that the fission process doesn't completely stop with control rod insertion. Water has to continue circulation in the reactor with reactor coolant pumps until the heat can be managed with Residual or Decay Heat Pumps. The cooling towers are the heat sink for the secondary coolant - secondary coolant carries away the heat from the primary coolant. I'm not sure exactly when cooling towers become unnecessary - generally nuclear plants are built along bodies of water such as rivers and the the river water acts as a final heat sink in both nuclear and fossil plants. Towers prevent heat related environmental damage to rivers, etc.

This is not intended to be a know all analysis. It's difficult to simplify and relate a lot of stuff in normal words. Also I admit that diagnostics in plants was my area of expertise; operating specifics beyond what we learned in school was generally something picked up while analyzing problems.

 

[AM64]

Edit: TLDR, the heat can be removed through evaporation (cooling tower) like what you're alluding to (water vapor) or can be removed via convection (cooling pond).

Below is a diagram if you're interested. The third loop here goes from the condenser to the cooling tower/pond.

View attachment 666504

That's a good diagram. The primary coolant loop is the red/yellow water circulating through the reactor and the steam generator. The secondary loop carries heat from the primary loop (steam generator secondary side) to the turbine with the condenser being the heat sink. The third loop is the water flowing into the condenser to cool the secondary loop - both the condenser and steam generator are generally liquid/liquid heat exchangers (B&W once through steam generators have a superheat region with pure steam at the top). As you point out the waste heat from the condenser (the third loop) is removed in the tower by convection cooling, and in time the tower won't be necessary. If environmental concerns are ignored the condenser water could simply be dumped into a body of water like a river.

The big concern is probably more if the Russians did something stupid and diverted the river away from the plant intakes rather than damaging the cooling towers. That and loss of offsite power and damage to continual onsite backup generation are the things to really worry about.

 

[Rocky_Top_Vol13]

 

[evillawyer]

Russia saving that precious Ukrainian ammo.

 

[volbound1700]

I am wondering if Kursk could be the pivotal turning point in this war.

 

[evillawyer]

 

[evillawyer]

 

[evillawyer]

Only thing that'd be funnier is Trump complaining about Melania sleeping with the pool boy

 

[MontyPython]

It's a good strategy given the amount of time it takes to become an veteran pilot.

I suppose if the price is right, they may come.

 

[norrislakevol]

Only thing that'd be funnier is Trump complaining about Melania sleeping with the pool boy

Karma is a b!tch!

 

[Rocky_Top_Vol13]

 

[evillawyer]

"blah blah blah ... Western death cult ... blah blah blah." - @volgr

 

[BeardedVol]

I wonder where they are going to house all of the Russian soldiers who are surrendering in Kursk?