But there is significant danger if the fighting causes these nuclear reactors (6) at the site to lose connection to offsite power.
What if they lost power because of a wildfire or tornado? Don’t they have some kind of plan for losing electricity?
DB2
What if they lost power because of a wildfire or tornado? Don’t they have some kind of plan for losing electricity?
Probably. But Jesus F.X. Christ. Let’s use just the teeniest, tiniest, smallest bit of common sense here. They probably have a plan for wildfire or tornado. They probably don’t have a plan for hostile invasion.
On TMF there is a faction that seems bent over backwards to justify Russia invading Ukraine. I get it. Putin is good because Trump likes him. Fine.
But no matter how much you admire Putin, it isn’t the Ukranian’s fault Russia is bombing the nuclear reactors.
Maybe, just maybe, this is the Russian’s fault.
What if they lost power because of a wildfire or tornado? Don’t they have some kind of plan for losing electricity?
These plants are normally self-powered for normal operations and use offsite power sources for backup.
If you lose both then you have a very serious situation.
OTFoolish
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…
syke6: But no matter how much you admire Putin, it isn’t the Ukranian’s fault Russia is bombing the nuclear reactors.
Maybe, just maybe, this is the Russian’s fault.
Oh absolutely … however I often wonder if we should attribute to malice that which may be adequately explained by incompetence and stupidity?
The Russian military leadership (and Vlad) have not shown a whole lot of cleverness so far in this endeavor? Their only answer to the protests at home is threats, arrests and pulling an old grandmother out of a crowd for holding up two signs?
While a large convoy requires a lot of logistical planning last I heard it was still mostly parked on the highway? When the news tries to report the news, they shut them down (ever hear of cell phones and the internet?). Many of the billionaires waited too long to hide their yachts and their currency is probably cheaper than toilet paper? Tanks shooting at nuclear power plants … I suppose a test of the design features?
Attacking populated cities with bombs and heavy artillary is so 1944? You may end up in military control of a humanitarian disaster area at a time when they can’t even seem to feed their own troops? Meanwhile the rest of the world has CNN and a whole lot of other international news on their multiple CRTs.
Tim <has a vision of Russian soldiers holding up signs “WILL SURRENDER FOR FOOD”>
These plants are normally self-powered for normal operations and use offsite power sources for backup.
If you lose both then you have a very serious situation.
OTFoolish
Gravity works well in ours. }};-D
Anymouse
http://nuclearsafety.gc.ca/eng/reactors/power-plants/nuclear…
Shutdown systems
All nuclear power reactors in Canada have two independent, fast-acting and equally effective shutdown systems.
The first shutdown system is made up of rods that drop automatically and stop the chain reaction if something irregular is detected.
The second system injects a liquid, or poison, inside the reactor to immediately stop the chain reaction.
Both systems work without power or operator intervention. However, they can also be manually activated.
These systems are regularly and safely tested.
What if they lost power because of a wildfire or tornado? Don’t they have some kind of plan for losing electricity?
—
Probably. But Jesus F.X. Christ. Let’s use just the teeniest, tiniest, smallest bit of common sense here. They probably have a plan for wildfire or tornado. They probably don’t have a plan for hostile invasion.
Probably not, but I was asking about this statement: “But there is significant danger if the fighting causes these nuclear reactors (6) at the site to lose connection to offsite power.”
Losing offsite power is losing offsite power, n’est pas?
DB2
What if they lost power because of a wildfire or tornado? Don’t they have some kind of plan for losing electricity?
DB2
=======================================================================
The only plan is to turn on their emergency diesel generators. However, these diesel generators (the size of locomotives) are not 100% reliable as demonstrated over years of operation at nuclear power plants. That is why they provide redundant diesel generators.
But we all know that large diesel generators like these require large amounts of diesel fuel and cooling water. Most nuclear plants provide one weeks worth of diesel fuel per generator. When the fuel runs out more fuel must be brought in by trucks. If more fuel is not brought in and diesel generators stop, then the Fukushima disaster will start.
Jaak
But we all know that large diesel generators like these require large amounts of diesel fuel and cooling water. Most nuclear plants provide one weeks worth of diesel fuel per generator. When the fuel runs out more fuel must be brought in by trucks. If more fuel is not brought in and diesel generators stop, then the Fukushima disaster will start.
Does this mean they couldn’t shut down the reactors in a week before the diesel runs out? That seems odd.
DB2
The cooling requirements of CAND reactors after the reactors are shut down are as follows:
Cooling systems need electricity to operate. Under normal operation, they get their electricity from the same power grid as the rest of us.
Nuclear power plants in Canada are also equipped with multiple sources of backup power if they get disconnected from the grid.
Sources of backup power include onsite power - that is, the power produced by the plant itself. [This is not allowed by safety regulations in most countries [i.e. USA] when a loss of offsite power (LOOP) occurs]
In addition, the following are available:
Two or three standby power generators [non-safety related]
Two or three emergency power generators [safety related]
Emergency batteries [sized for only 4-8 hours without charging]
[These diesel generators require diesel fuel and cooling water]
You can learn more by watching what would happen in the very unlikely event of a total station blackout – the situation that led to the Fukushima accident following the large tsunami that destroyed all available power sources onsite.
http://nuclearsafety.gc.ca/eng/reactors/power-plants/nuclear…
Jaak
Does this mean they couldn’t shut down the reactors in a week before the diesel runs out? That seems odd.
DB2
=======================================================
Not at all odd. That is a well understood “Achilles Heel” of nuclear power plant design and operation. Here is the simple explanation:
On a loss of offsite power situation reactors are shutdown in minutes. The problem then is keeping the reactor core cooled for weeks. The reactor core is radioactive and keeps generating decay heat which is what happened at Fukushima. With no reactor core cooling, the core begins to melt, the fuel cladding reacts with the steam and produces hydrogen, when the hydrogen reaches explosive levels an explosion occurs while the reactor core keeps melting.
Jaak
Does this mean they couldn’t shut down the reactors in a week before the diesel runs out? That seems odd.
That isn’t how a nuclear reactor works.
Even after you shut it down there is what is called decay heat that has to be removed…for a long time.
Right after shutdown from full power the reactor still produces 6%-7% of full heat that has to be removed. This amount decays down to about 1% after 24 hours. But that is still a lot of BTUs.
Cooling water needs to be circulated to remove this heat.
This is one of the key safety improvements in some newer reactor designs, having the ability to circulate cooling water without the need for pumps.
The note from Tim about the Canadian reactors being able to shutdown with control rods OR chemically (Boron) makes no difference. Shutting down just means no nuclear chain reaction…decay heat still has to be removed (not sure how the Canadian reactors handle this)
Mike
That isn’t how a nuclear reactor works.
Even after you shut it down there is what is called decay heat that has to be removed…for a long time.
Right after shutdown from full power the reactor still produces 6%-7% of full heat that has to be removed. This amount decays down to about 1% after 24 hours. But that is still a lot of BTUs.
Cooling water needs to be circulated to remove this heat.
This is one of the key safety improvements in some newer reactor designs, having the ability to circulate cooling water without the need for pumps.
^ This issue was the core reason for the Chernobyl disaster. The plant had backup generators, but they took about a minute or so to reach full power. The Russians wanted to test using the residual heat to generate power for the cooling pumps in the interim.
Turns out, that’s not a good idea.
It was also the core reason for the Fukushima disaster. The backup generators got knocked out by the tsunami.
In numerous conversations we’ve had about nuclear power over the years, someone invariably says “if we just got rid of all the regulations it would be cost effective.” That’s true, but not accounting for every contingency leads to disaster. And disasters are really not cost effective.
Shutting down just means no nuclear chain reaction…decay heat still has to be removed (not sure how the Canadian reactors handle this)
Mike
I don’t claim to be a nuclear engineer but my understanding is that the rods are held in place magnetically, when the power quits they fall into the cooling pond below.
Both China, India and others are using the CANDU Heavy water reactors. India has in the past experimented with using thorium as fuel because they don’t have domestic uranium reserves … oh still going on?
https://www.google.com/search?q=india+thorium+reactor+progre…
https://www.google.com/search?q=how+many+candu+reactors+in+t…
Another nice feature is the ability to refuel while the reactor is operating. I think this is because they use natural uranium rather than enriched?
https://www.neimagazine.com/news/newscanadas-darlington-1-br….
Anymouse
^ This issue was the core reason for the Chernobyl disaster.
===================
The biggest problem at Chernobyl was the design of the reactor, which resulted in a positive void coefficient. The positive void coefficient produced a runaway positive feedback loop during the strange experiment they were running. In short, boiling in the reactor produced more power, which resulted in more boiling, and even more power. Things got out of control very quickly and the reactor tore itself apart with a large steam explosion from the quick power spike.
All of the discussion in other posts about emergency power ignores things like steam-driven emergency feedwater pumps. Those safety systems are very common in the US, and something like them exist in PWRs as well as BWRs. Steam is produced in either the steam generators or reactor. The steam goes to drive a small turbine connected to a pump. The pump then delivers cooling water back to the steam generators or reactor. No outside power is needed drive the pump. There might be a small amount of electricity needed to run the control systems for the pump and regulation valves, but that is a small draw.
All of the discussion in other posts about emergency power ignores things like steam-driven emergency feedwater pumps. Those safety systems are very common in the US, and something like them exist in PWRs as well as BWRs. Steam is produced in either the steam generators or reactor. The steam goes to drive a small turbine connected to a pump. The pump then delivers cooling water back to the steam generators or reactor. No outside power is needed drive the pump. There might be a small amount of electricity needed to run the control systems for the pump and regulation valves, but that is a small draw.
===================================================================
This is a complex Mickey Mouse way to recover from a Station Blackout. It did not work at Fukushima. Most operators do not know how to do all this reconfiguration during a Station Blackout. It was does not provide any electricity to monitor the status of the reactor, the containment, and many other safety systems. It is not part of any design basis accident procedure authorized by NRC.
Jaak
The plant operators I know would disagree. The Auxiliary Feedwater Pumps I am familiar with are Safety Class 2 systems. That means they are SAFETY RELATED, and are needed for safe shutdown during accident scenarios.
I only did a short Google search, but below is what Westinghouse says about steam-driven emergency pumps in nuclear power plants.
https://www.westinghousenuclear.com/Portals/0/operating%20pl…
The most safety-significant systems in the case of an SBO [Station Blackout] in a nuclear power plant are the reactor core isolation cooling (RCIC) system for boiling water reactors (BWRs) and the auxiliary feedwater (AFW) system for pressurized water reactors (PWRs). The steam-driven water pump in these systems is typically the frontline component that addresses SBO and provides core heat removal.
If I wanted to spend more time on, I could provide more documentation on the safety significance of these systems. They are not “Mickey Mouse”.
I don’t claim to be a nuclear engineer but my understanding is that the rods are held in place magnetically, when the power quits they fall into the cooling pond below.
You are still confusing the process of shutting down (inserting control rods or chemicals) and the process of removing heat. Even in normal operation where the operators slowly insert the control rods to perform a shutdown, the decay heat has to be removed in the days after. Note that a slow shutdown generates less decay heat than a sudden shutdown.
I think most designs hold the rods electromagnetically … and then some type of ratchet keeps them from bounding back up.
But in the following second gobs of decay heat is generated that must be removed to prevent damage.
And this heat gradually declines. Probably hundreds of good web sites that can explain all this with nice graphs.
Most disaster plans assume some numbers of days that external power must be supplied to keep the cooling pumps running AFTER the control rods have shutdown due to loss of power (or other reason). The also assume that things like diesel fuel can get resupplied.
I doubt they have planned for a military invasion.
Mike
The plant operators I know would disagree. The Auxiliary Feedwater Pumps I am familiar with are Safety Class 2 systems. That means they are SAFETY RELATED, and are needed for safe shutdown during accident scenarios.
====================================================
Yes it can be used for short term Station Blackout. But after 4 hours it is questionable that these AFW pumps can continue operation because of lack of electricity from batteries. Even Westinghouse says so in the link you provided. Here is Westinghouse statement:
“Proper operation of the AFW system in a PWR traditionally requires DC power from a station
battery, steam from the steam generators and an adequate supply of secondary plant water. The total amount of current draw on the station battery can be a limiting factor in determining the duration of SBO coping.”
https://www.westinghousenuclear.com/Portals/0/operating%20pl…
Again I say that the AFW for long term (>4 hours) Station Blackout is Mickey Mouse. I am also an expert on nuclear power plant systems having worked for Westinghouse and Bechtel Power Corporation for over 30 years on nuclear power plant engineering.
Fukushima became a disaster in their long term Station Blackout.
Jaak
If anyone hasn’t seen the amazing HBO series “Chernobyl” I highly recommend it. In it, there is a court scene which has an incredibly lucid explanation of exactly what went wrong. Videos are below, each is about three minutes. If anyone has an interest in this topic it is well worth a watch.
https://www.youtube.com/watch?v=TmIEI4ky-Zc
https://www.youtube.com/watch?v=3azNLCo0wyU
https://www.youtube.com/watch?v=IzbOgvWQhHA
The whole series is well worth a watch too. On one hand are the fumbling, bumbling Soviet bureaucrats, and on the other are the incredibly heroic Russian people. Ripping good yarn. Great acting and all star cast.
syke6’s three links of the Chernobyl movie are representative of the excellence of the movie, and show not only the fatal flaw in much nuclear reactor design but also the fatal flaw in modern human culture. The “men who worked in the control room” of a nuclear power plant “did not understand it either.” Ummm, that was the death sentence. A universal death sentence for modernity if we do not change course.
LOOK, there is something utterly, almost incomprehensibly important, but that important thing is something that “we”*** do not want to accept or even take cognizance of; the possibiity that the catastrophes we are now in and others that we are bringing on ourselves is because of our clinging to one of the fundamental superstitions of mankind: that the sandbox playground of earth will always somehow renew itself erasing our idiocies so we can “play again”. NO.
HUMANS have become the “controllers” of something far more complex and almost infinitely more powerful than a nuclear reactor, to wit, a planetary atmospheric and ecological system now [for the first time in planetary history] profoundly linked to our amoral human political economic systems.
Disaster disaster disaster.
Yes, my point is that GCC and Chernobyl and the idiocy of Putin and others I will not name are all symptoms of the failure of human wisdom to grow anywhere near as rapidly as human knowledge. The growth of human knowledge is now driven more by avarice and power hunger than by an awed loving curiosity about the universe.
So we are damned.
david fb
the ***we above is the crux of the post. I mean by that “we” not only an aggregation of billions of individual “I’s”, but more profoundly by far the now dying and looted common wealth of our mutually inherited wisdom and loving connection across generations through all time.