4 ms·

That's the average. But you'd need a few more for peak demand and a few more for when these are offline for maintenance, refuelling etc.

dahfizz 5y ago
A bit of pumped hydro storage would also satisfy those needs.
- sascha_sl 5y ago
  PSH could not bridge demand for long enough. Maintenance cycles on nuclear reactors can be quite long.
  - krasin 5y ago
    Make it 8 stations instead of 7 to have an excess of energy and then use the extra energy, when there's not enough demand, to produce fertilizers or other energy-intensive goods.
londons_explore 5y ago
I suspect in today's world of maximizing capital efficiency, and being able to contract in large numbers of people, the very expensive power plant won't be offline for long for maintenance. They'll probably shut the plant down, and have 500 workers come in to replace everything that needs to be replaced, and then power it up again within a few days, and let it run for another 6 months or so. Everything will be planned on workplans, and most won't require specialist knowledge... Eg. "Replace pump 205 in building C with this pump. Required skills people: 2x plumber, 2x electrician".
- akiselev 5y ago
  Most reactor downtime is due to refueling, since that requires cooling down the core through several stages. AFAIK it's not practical to do it safely and economically in under a few weeks. Most reactor maintenance is already done during refueling so there isn't much more room to optimize that downtime. (though that may change the older a reactor gets)
  - _n_b_ 5y ago
    Most reactor downtime is actually for maintenance during refueling windows. As I mentioned in another comment, there is experience doing refuelling-only outages in <10 days. If everything goes well, you can startup a PWR from cold shutdown to hot full power in 3 12 hour shifts
- _n_b_ 5y ago
  That is exactly how nuclear outages work. Everything is planned in a resource-loaded schedule and many of those resources are just there for the outage. Finland is actually somewhat known for running short (1 year) cycles with very very short (<10 days for refuelling is not unheard of) refuelling outages every other cycle alternating with slightly longer maintenance outages. A more typical scenario in the US would be 18 month cycles with a 30ish day outage. Some plants are moving to 24 month cycles with slightly longer outages. Capacity factor for nuclear plants in the US is consistently around 93% (similar figures in many other countries as well), which is significantly higher than other generation sources.
- ncmncm 5y ago
  Rushing maintenance costs more, and nuke operating cost is already radically more than renewables + storage.
anonporridge 5y ago
Ideally, you overbuild and have some flexible consumer of electricity that can arbitrarily ramp consumption up or down to suck off any excess supply whenever inflexible basal civilization demand doesn't match supply, e.g. ramp up when everyone is asleep and ramp down if a reactor needs to go offline. This is called demand response, https://www.energy.gov/oe/activities/technology-development/grid-modernization-and-smart-grid/demand-response https://www.energy.gov/oe/activities/technology-development/..., and it's probably as important of a component to future grid management as energy storage.
- retrac 5y ago
  Right. A useful sink for surplus energy could be something like surplus heat or electricity to synthesize carbon-neutral fuels. We're not likely to get large electric aircraft anytime soon.
  - anonporridge 5y ago
    Electric aircraft doesn't really strike me as this kind of customer. Aircraft has relatively inflexible fueling demands based on customer demand that is reserved weeks ahead of time. Bitcoin mining is commonly promoted as this kind of ideal electricity consumer. Hydrogen production could be another. However, I think more interesting for this community would be to build some kind of demand response general computing datacenter. Basically, sell computing resources with poor availability guarantees, but at a cheaper rate than standard datacenters. i.e. we'll run your batch jobs very cheaply, but we can't give you strong guarantees about how long it will take because we have to wait for excess grid electricity to have the energy to run them. Best case that's every night. Worst case we won't be able to run anything for weeks because Texas is going through another freak winter storm.
    - Gare 5y ago
      > Electric aircraft doesn't really strike me as this kind of customer. Aircraft has relatively inflexible fueling demands based on customer demand that is reserved weeks ahead of time. I think you misunderstood. The parent comment implied that excess electricity could be use to produce synthetic fuels (via carbon capture) to power conventional airplanes, ships or other machinery.

dahfizz 5y ago

A bit of pumped hydro storage would also satisfy those needs.

sascha_sl 5y ago
PSH could not bridge demand for long enough. Maintenance cycles on nuclear reactors can be quite long.
- krasin 5y ago
  Make it 8 stations instead of 7 to have an excess of energy and then use the extra energy, when there's not enough demand, to produce fertilizers or other energy-intensive goods.

londons_explore 5y ago

I suspect in today's world of maximizing capital efficiency, and being able to contract in large numbers of people, the very expensive power plant won't be offline for long for maintenance. They'll probably shut the plant down, and have 500 workers come in to replace everything that needs to be replaced, and then power it up again within a few days, and let it run for another 6 months or so. Everything will be planned on workplans, and most won't require specialist knowledge... Eg. "Replace pump 205 in building C with this pump. Required skills people: 2x plumber, 2x electrician".

akiselev 5y ago
Most reactor downtime is due to refueling, since that requires cooling down the core through several stages. AFAIK it's not practical to do it safely and economically in under a few weeks. Most reactor maintenance is already done during refueling so there isn't much more room to optimize that downtime. (though that may change the older a reactor gets)
- _n_b_ 5y ago
  Most reactor downtime is actually for maintenance during refueling windows. As I mentioned in another comment, there is experience doing refuelling-only outages in <10 days. If everything goes well, you can startup a PWR from cold shutdown to hot full power in 3 12 hour shifts
_n_b_ 5y ago
That is exactly how nuclear outages work. Everything is planned in a resource-loaded schedule and many of those resources are just there for the outage. Finland is actually somewhat known for running short (1 year) cycles with very very short (<10 days for refuelling is not unheard of) refuelling outages every other cycle alternating with slightly longer maintenance outages. A more typical scenario in the US would be 18 month cycles with a 30ish day outage. Some plants are moving to 24 month cycles with slightly longer outages. Capacity factor for nuclear plants in the US is consistently around 93% (similar figures in many other countries as well), which is significantly higher than other generation sources.
ncmncm 5y ago
Rushing maintenance costs more, and nuke operating cost is already radically more than renewables + storage.

anonporridge 5y ago

Ideally, you overbuild and have some flexible consumer of electricity that can arbitrarily ramp consumption up or down to suck off any excess supply whenever inflexible basal civilization demand doesn't match supply, e.g. ramp up when everyone is asleep and ramp down if a reactor needs to go offline. This is called demand response, https://www.energy.gov/oe/activities/technology-development/grid-modernization-and-smart-grid/demand-response https://www.energy.gov/oe/activities/technology-development/..., and it's probably as important of a component to future grid management as energy storage.

retrac 5y ago
Right. A useful sink for surplus energy could be something like surplus heat or electricity to synthesize carbon-neutral fuels. We're not likely to get large electric aircraft anytime soon.
- anonporridge 5y ago
  Electric aircraft doesn't really strike me as this kind of customer. Aircraft has relatively inflexible fueling demands based on customer demand that is reserved weeks ahead of time. Bitcoin mining is commonly promoted as this kind of ideal electricity consumer. Hydrogen production could be another. However, I think more interesting for this community would be to build some kind of demand response general computing datacenter. Basically, sell computing resources with poor availability guarantees, but at a cheaper rate than standard datacenters. i.e. we'll run your batch jobs very cheaply, but we can't give you strong guarantees about how long it will take because we have to wait for excess grid electricity to have the energy to run them. Best case that's every night. Worst case we won't be able to run anything for weeks because Texas is going through another freak winter storm.
  - Gare 5y ago
    > Electric aircraft doesn't really strike me as this kind of customer. Aircraft has relatively inflexible fueling demands based on customer demand that is reserved weeks ahead of time. I think you misunderstood. The parent comment implied that excess electricity could be use to produce synthetic fuels (via carbon capture) to power conventional airplanes, ships or other machinery.