Energy sources and manpower required to maintain operation for x time

[Jokodo]

What's the typical size of a skeleton crew required to maintain operation and deal with plausible unexpected circumstances without outside intervention, say per GW of output for a limited amount of time?

For how long would such a skeleton crew typically be able to maintain operation independently?

Say for a nuclear power plant, how many staff is required for operation, and how long would the fuel on site typically last? Same for coal power, hydro (minus "fuel on site"), biomass (presumably worst for manpower), etc.

I've had a discussion with someone elsewhere who was voicing the opinion that in this Year of Pestilence (or more precisely: if we were ever to be hit by another pandemic with higher fatality rate), nuclear reactors become an unforseeable risk if/when they run out of operators as they fall sick one after the other. I countered that, on the other hand, since they need less manpower to maintain operation than pretty any other energy source, it becomes much more feasible to send a skeleton crew into isolation before the outbreak hits hard, to ensure operation - which I'm sure is already happening all around the world.

I don't actually have numbers to back this up or make it more specific. Does anyone?

 

[Loren Pechtel]

Coal plants need people with heavy lifting equipment (I think they use earthmoving equipment but I'm not sure) on a daily basis to keep the boilers fed. Nuke goes for several months without being refueled and you can go over the normal interval but eventually the output drops. (The rods actually have enough fuel for several years, the problem is waste products build up that love to absorb neutrons and thus poison the reaction. This turns down the maximum throttle, eventually to the point the reactor won't work at all.) No idea on other plants.

I do agree that in the case of major pestilence reactors become a liability--but if it's that bad a bunch of reactors going Fukushima won't matter in the big picture. (The reactors can safely shut themselves down, the problem is even when you hit the big red button you set the throttle to 3%, not 0%. Nothing but time will bring it down from there and you have to keep it supplied with cooling water. That's what happened to Fukushima--they ended up with no power to run the pumps to provide that cooling water. The spent fuel pool also had the same problem.) If we have the sort of pestilence that leaves the reactors without even skeleton crews you're looking at civilization-ending event.

 

[Jokodo]

Coal plants need people with heavy lifting equipment (I think they use earthmoving equipment but I'm not sure) on a daily basis to keep the boilers fed. Nuke goes for several months without being refueled and you can go over the normal interval but eventually the output drops. (The rods actually have enough fuel for several years, the problem is waste products build up that love to absorb neutrons and thus poison the reaction. This turns down the maximum throttle, eventually to the point the reactor won't work at all.) No idea on other plants.

I do agree that in the case of major pestilence reactors become a liability--but if it's that bad a bunch of reactors going Fukushima won't matter in the big picture. (The reactors can safely shut themselves down, the problem is even when you hit the big red button you set the throttle to 3%, not 0%. Nothing but time will bring it down from there and you have to keep it supplied with cooling water. That's what happened to Fukushima--they ended up with no power to run the pumps to provide that cooling water. The spent fuel pool also had the same problem.) If we have the sort of pestilence that leaves the reactors without even skeleton crews you're looking at civilization-ending event.

I guess my question is less "what happens when everyone falls sick" and more "if they see it coming, how many healthy people would have to be put in quarantine to keep operations up, and how long would this skeleton crew be able to operate the plant with outside (fuel/parts) supplies?

 

[bilby]

Coal plants need people with heavy lifting equipment (I think they use earthmoving equipment but I'm not sure) on a daily basis to keep the boilers fed. Nuke goes for several months without being refueled and you can go over the normal interval but eventually the output drops. (The rods actually have enough fuel for several years, the problem is waste products build up that love to absorb neutrons and thus poison the reaction. This turns down the maximum throttle, eventually to the point the reactor won't work at all.) No idea on other plants.

I do agree that in the case of major pestilence reactors become a liability--but if it's that bad a bunch of reactors going Fukushima won't matter in the big picture. (The reactors can safely shut themselves down, the problem is even when you hit the big red button you set the throttle to 3%, not 0%. Nothing but time will bring it down from there and you have to keep it supplied with cooling water. That's what happened to Fukushima--they ended up with no power to run the pumps to provide that cooling water. The spent fuel pool also had the same problem.) If we have the sort of pestilence that leaves the reactors without even skeleton crews you're looking at civilization-ending event.

A civilisation ending pestilence, not a civilisation ending meltdown.

If every single nuclear reactor in the world melted down Fukushima style, the death toll would be zero (as it was at Fukushima).

Nuclear reactor accidents are expensive. They are not dangerous (unless you are in the Soviet Union, which you're not, because it hasn't existed for nearly three decades).

The underlying premise of the OP question - that a nuclear power plant becomes dangerous if abandoned - is simply untrue. It's possible for such an abandonment (if very sudden and with no time to prepare for a lack of staff) to result in the destruction of an expensive asset. And perhaps an expensive cleanup (if anyone cares to bother). But no lives would be at risk.

 

[bilby]

Coal plants need people with heavy lifting equipment (I think they use earthmoving equipment but I'm not sure) on a daily basis to keep the boilers fed. Nuke goes for several months without being refueled and you can go over the normal interval but eventually the output drops. (The rods actually have enough fuel for several years, the problem is waste products build up that love to absorb neutrons and thus poison the reaction. This turns down the maximum throttle, eventually to the point the reactor won't work at all.) No idea on other plants.

I do agree that in the case of major pestilence reactors become a liability--but if it's that bad a bunch of reactors going Fukushima won't matter in the big picture. (The reactors can safely shut themselves down, the problem is even when you hit the big red button you set the throttle to 3%, not 0%. Nothing but time will bring it down from there and you have to keep it supplied with cooling water. That's what happened to Fukushima--they ended up with no power to run the pumps to provide that cooling water. The spent fuel pool also had the same problem.) If we have the sort of pestilence that leaves the reactors without even skeleton crews you're looking at civilization-ending event.

I guess my question is less "what happens when everyone falls sick" and more "if they see it coming, how many healthy people would have to be put in quarantine to keep operations up, and how long would this skeleton crew be able to operate the plant with outside (fuel/parts) supplies?

Most plants could be run with a very small staff, if you are not concerned about regulatory compliance, but only with generating electricity.

Outside fueling/defueling, which is needed only every year or two, a six man team could keep a nuclear reactor running 24x7. Of course, that would likely mean that once something went wrong (probably in the ancillary equipment outside the reactor vessel itself, which has few moving parts) it would require a fairly extended shutdown to fix it. And you wouldn't get any government in a nuclear power generating nation to allow you to run a plant without security guards (for example), or even without a small army of documentation compliance staff to report to the regulator evey time someone forgets to file a form in triplicate.

Most naval reactors are basically miniature PWRs; They routinely operate with a fairly small crew (an Ohio class sub only has about 140 crew in total, most of whom are not in any way involved in reactor operations). Of course, they don't refuel while on patrol (and the very long time between fuellings is a major asset - nuclear subs can make their own water and oxygen, so the duration of a patrol is limited only by the amount of food they can carry*).












*And the psychological endurance of the crew.

 

[Jokodo]

Coal plants need people with heavy lifting equipment (I think they use earthmoving equipment but I'm not sure) on a daily basis to keep the boilers fed. Nuke goes for several months without being refueled and you can go over the normal interval but eventually the output drops. (The rods actually have enough fuel for several years, the problem is waste products build up that love to absorb neutrons and thus poison the reaction. This turns down the maximum throttle, eventually to the point the reactor won't work at all.) No idea on other plants.

I do agree that in the case of major pestilence reactors become a liability--but if it's that bad a bunch of reactors going Fukushima won't matter in the big picture. (The reactors can safely shut themselves down, the problem is even when you hit the big red button you set the throttle to 3%, not 0%. Nothing but time will bring it down from there and you have to keep it supplied with cooling water. That's what happened to Fukushima--they ended up with no power to run the pumps to provide that cooling water. The spent fuel pool also had the same problem.) If we have the sort of pestilence that leaves the reactors without even skeleton crews you're looking at civilization-ending event.

I guess my question is less "what happens when everyone falls sick" and more "if they see it coming, how many healthy people would have to be put in quarantine to keep operations up, and how long would this skeleton crew be able to operate the plant with outside (fuel/parts) supplies?

Most plants could be run with a very small staff, if you are not concerned about regulatory compliance, but only with generating electricity.

Outside fueling/defueling, which is needed only every year or two, a six man team could keep a nuclear reactor running 24x7.

That would be six people total, working in shifts, for two to three people on duty during normal operation? Or shifts of six people each?

Of course, that would likely mean that once something went wrong (probably in the ancillary equipment outside the reactor vessel itself, which has few moving parts) it would require a fairly extended shutdown to fix it.

How much more staff would be needed to ensure that operations can be quickly resumed in such a case?

And you wouldn't get any government in a nuclear power generating nation to allow you to run a plant without security guards (for example), or even without a small army of documentation compliance staff to report to the regulator evey time someone forgets to file a form in triplicate.

So add another 15-20 to the six?

And how does this compare to other methods of power generation? Per GW of electricity output, how large would a skeleton crew have to be for a coal plant? For hydroelectric dams? How long does the coal stored on site last for a typical coal plant vs. for a typical nuclear plant? Obviously if we include mining and transport, the figures explode and isolating the entire supply chain from the outside world becomes implausible, so this is also a relevant difference.

 

[barbos]

For that to become a problem you need significant drop in man power - 30-50%. It would be Mad Max scenario long before that.

 

[Jokodo]

For that to become a problem you need significant drop in man power - 30-50%. It would be Mad Max scenario long before that.

Three chance that, say 50% of a small crew fall sick at roughly the same time and become inoperative for a couple weeksis non negligible lon3g before.

 

[barbos]

For that to become a problem you need significant drop in man power - 30-50%. It would be Mad Max scenario long before that.

Three chance that, say 50% of a small crew fall sick at roughly the same time and become inoperative for a couple weeksis non negligible lon3g before.

But there is a large number of nuclear plants, they can all share qualified workers. Recently retired can go back to work, and then there are nukes in the navy, these guys with some training can be employed too.

 

[Jokodo]

For that to become a problem you need significant drop in man power - 30-50%. It would be Mad Max scenario long before that.

Three chance that, say 50% of a small crew fall sick at roughly the same time and become inoperative for a couple weeksis non negligible lon3g before.

But there is a large number of nuclear plants, they can all share qualified workers. Recently retired can go back to work, and then there are nukes in the navy, these guys with some training can be employed too.

That may work in big countries like Russia or the USA. Around here, Slovenia has one plant with one reactor, Hungary one with four reactors, Slovakia two with four reactors total, Czechia also two, Austria none (only one or two small research reactors), and Croatia none, though it owns a share of Slovenia's Krsko plant, Serbia also nonesince it closed the one it had. How readily are they going to share personell in a Time of Pestilence and closed borders when every one looks after their own first and foremost?

And none of these countries had nukes in the navy. Most don't have a navy.

 

[barbos]

But there is a large number of nuclear plants, they can all share qualified workers. Recently retired can go back to work, and then there are nukes in the navy, these guys with some training can be employed too.

That may work in big countries like Russia or the USA. Around here, Slovenia has one plant with one reactor, Hungary one with four reactors, Slovakia two with four reactors total, Czechia also two, Austria none (only one or two small research reactors), and Croatia none, though it owns a share of Slovenia's Krsko plant, Serbia also nonesince it closed the one it had. How readily are they going to share personell in a Time of Pestilence and closed borders when every one looks after their own first and foremost?

And none of these countries had nukes in the navy. Most don't have a navy.

Well, as I said, if it's a Mad Max scenario then nuclear plants are the least of your problems. If it's not there yet then it's in interest of the neighboring countries to keep your lonely nuclear plant safe.

 

[Jokodo]

But there is a large number of nuclear plants, they can all share qualified workers. Recently retired can go back to work, and then there are nukes in the navy, these guys with some training can be employed too.

That may work in big countries like Russia or the USA. Around here, Slovenia has one plant with one reactor, Hungary one with four reactors, Slovakia two with four reactors total, Czechia also two, Austria none (only one or two small research reactors), and Croatia none, though it owns a share of Slovenia's Krsko plant, Serbia also nonesince it closed the one it had. How readily are they going to share personell in a Time of Pestilence and closed borders when every one looks after their own first and foremost?

And none of these countries had nukes in the navy. Most don't have a navy.

Well, as I said, if it's a Mad Max scenario then nuclear plants are the least of your problems. If it's not there yet then it's in interest of the neighboring countries to keep your lonely nuclear plant safe.

I wouldn't bet on that, nationalists can be quite irrational, and closing the borders (and especially locking in essential personell) is a natural reflex in times of crisis - long before any Mad Max scenario.

I totally agree by the way that in a Mad Max scenario, nuclear plants don't make it into the top 40 problems, but that's not what I'm talking about.

 

[barbos]

Well, as I said, if it's a Mad Max scenario then nuclear plants are the least of your problems. If it's not there yet then it's in interest of the neighboring countries to keep your lonely nuclear plant safe.

I wouldn't bet on that, nationalists can be quite irrational, and closing the borders (and especially locking in essential personell) is a natural reflex in times of crisis - long before any Mad Max scenario.

I can see how it can explain ordinary people hoarding food or other materials. But don't worry, US will send people to run slovenian reactor if you promise not to force them to play oral beer pong

 

[Jokodo]

Well, as I said, if it's a Mad Max scenario then nuclear plants are the least of your problems. If it's not there yet then it's in interest of the neighboring countries to keep your lonely nuclear plant safe.

I wouldn't bet on that, nationalists can be quite irrational, and closing the borders (and especially locking in essential personell) is a natural reflex in times of crisis - long before any Mad Max scenario.

I can see how it can explain ordinary people hoarding food or other materials. But don't worry, US will send people to run slovenian reactor if you promise not to force them to play oral beer pong

But that's what we do in Central Europe. It's our culture, you have to respect our culture if you want to come here!

 

[bilby]

Most plants could be run with a very small staff, if you are not concerned about regulatory compliance, but only with generating electricity.

Outside fueling/defueling, which is needed only every year or two, a six man team could keep a nuclear reactor running 24x7.

That would be six people total, working in shifts, for two to three people on duty during normal operation? Or shifts of six people each?

Six total. A normally operating reactor requires little to no intervention on a daily basis. One guy is there to watch for alarms, and the other to punch him if he tries to change anything.

Of course, that would likely mean that once something went wrong (probably in the ancillary equipment outside the reactor vessel itself, which has few moving parts) it would require a fairly extended shutdown to fix it.

How much more staff would be needed to ensure that operations can be quickly resumed in such a case?

As many as the number of centimetres a piece of string is long.

And you wouldn't get any government in a nuclear power generating nation to allow you to run a plant without security guards (for example), or even without a small army of documentation compliance staff to report to the regulator evey time someone forgets to file a form in triplicate.

So add another 15-20 to the six?

Or cut the needless paperwork, and just lock the gates and give the skeleton staff keys.

And how does this compare to other methods of power generation? Per GW of electricity output, how large would a skeleton crew have to be for a coal plant? For hydroelectric dams? How long does the coal stored on site last for a typical coal plant vs. for a typical nuclear plant? Obviously if we include mining and transport, the figures explode and isolating the entire supply chain from the outside world becomes implausible, so this is also a relevant difference.

Hydropower requires few employees; More than nuclear, but fewer than coal.

The major difference between coal and nuclear in terms of manpower is fuelling. in a PWR, that's a project that happens every year (or two, or three), and runs for a week or two. If you are prepared to accept reduced power output, it could be put off almost indefinitely without harming the reactor itself; after a decade you might only be getting a few percent of the nameplate power output, but after a decade of apocalyptic pandemic disease, you probably only have a few percent of the customers you started with.

In a CANDU or Magnox reactor, fuelling is more continuous and in CANDU reactors can be done without shutting down; However that's a function of these older designs being optimised for production of Plutonium 239, rather than electricity. Modern power plants make contaminated Pu (with a significant percentage of Pu-240), which is unimportant to commercial operations, but renders them useless for weapons manufacturing. This is entirely a consequence of the long time between fuellings.

Coal power stations need constant fuelling and removal of ash.

In an emergency, several weeks of fuel could be stockpiled at coal power plants - this was done in the UK in the 1980s when the coal miners threatened to strike, and caused the strike to drag on once it was called, as the government could keep the lights on. But in normal operations, it is unusual for a coal plant to have more than a couple of days worth of fuel on site; Coal is brought in continuously, and stockpiles are (quite correctly) viewed as wasteful. Even a few days worth of coal requires a lot of land on which to store it.

 

[Loren Pechtel]

A civilisation ending pestilence, not a civilisation ending meltdown.

Yeah, I'm saying that if the pestilence is bad enough to take out the reactors it's going to do a major number on civilization.

If every single nuclear reactor in the world melted down Fukushima style, the death toll would be zero (as it was at Fukushima).

Here I disagree--there would be deaths, but not all that many. Fukushima had a bunch of highly skilled people trying to keep it under control. In the scenario being envisioned there likely would not be unless the reactors were shut down ahead as a precaution.

 

[bilby]

A civilisation ending pestilence, not a civilisation ending meltdown.

Yeah, I'm saying that if the pestilence is bad enough to take out the reactors it's going to do a major number on civilization.

If every single nuclear reactor in the world melted down Fukushima style, the death toll would be zero (as it was at Fukushima).

Here I disagree--there would be deaths, but not all that many. Fukushima had a bunch of highly skilled people trying to keep it under control. In the scenario being envisioned there likely would not be unless the reactors were shut down ahead as a precaution.

At least one of the Fukushima meltdowns would have been avoided if there had been no humans second guessing the automatic cooling systems.

An abandoned reactor is likely to be safer than one with a full staff - humans worry about the wrong things. Such as not letting the system cool too fast, to avoid potential damage to the heat exchangers - and instead inadvertently not letting it cool at all, leading to actual damage to the reactor core.

Basically, the automatic systems assume the worst case - and get overridden by humans who tend to think the situation just isn't serious enough to warrant extreme measures, until it's far too late. Nobody wants to explain to his boss why he let the heat exchanger piping implode due to crashing temperatures, and nobody wants to believe that the alternative is to have to explain why he caused a core meltdown.

Nuclear power plants are a bit like modern commercial jetliners in this regard - they are so safe that human intervention almost always makes things worse, even when the human in question is highly trained and experienced. Almost all accidents in both industries are at least partially due to human error, and almost always the error consists in doing something, when doing nothing would have been a far better choice.

 

[barbos]

Fukushima reactor was not well designed and it did require competent human intervention in order to prevent a disaster which it did not receive and it ended up in a disaster. Of course it could have been worse.

 

[bilby]

Fukushima reactor was not well designed and it did require competent human intervention in order to prevent a disaster which it did not receive and it ended up in a disaster. Of course it could have been worse.

Certainly there were some design flaws in all four reactors at Fukushima; All were slightly different, and all were Gen I PWRs with features that haven't been permitted in new reactors since the 1970s.

It remains the case that human intervention made things worse, in the case of at least one of the reactors. People tend not to think things through effectively after a massive calamity. Of course, many of the sensible things that they wanted to do were simply impossible, due to the damage caused by the tsunami and earthquake. If they could have simply trucked in a generator a couple of days after the tsunami struck, no major issues would have occurred; The reactors could have been shut down and cooled in an orderly fashion, and been ready to start up again as soon as the grid could be repaired so they had a connection to their customers.

But it turns out that getting a large generator to a site where all the roads, and even all the places you might land a helicopter, are choked with millions of tonnes of debris, is a bit difficult. Particularly when most of the portable generators in the region were just destroyed by a tsunami.

 

[fromderinside]

Maybe a water based generator powered by a nuclear system could have sufficed if someone had only contacted the US Navy submarine base near Tokyo. Back in the day we had competent presidents.