Japan has restarted five nuclear power reactors in 2018

[thackney]

Japan has restarted five nuclear power reactors in 2018
https://www.eia.gov/todayinenergy/detail.php?id=37633
NOVEMBER 28, 2018



Shikoku Electric Power Co. restarted the 890 megawatt (MW) Ikata-3 reactor in Japan’s Ehime Prefecture at the end of October, the fifth nuclear reactor in Japan to be restarted in 2018. Japan had suspended its nuclear fleet in 2013 for mandatory safety checks and upgrades following the 2011 Fukushima accident, and before 2018 only four reactors had been restarted.

Following the Fukushima accident, as each Japanese nuclear reactor entered its scheduled maintenance and refueling outage, it was not returned to operation. Between September 2013 and August 2015, Japan's entire reactor fleet was suspended from operation, leaving the country with no nuclear generation. Sendai Units 1 and 2, in Japan’s Kagoshima Prefecture, were the first reactors to be restarted in August and October 2015, respectively.

The restart of Japan's nuclear power plants requires the approval of both Japan's Nuclear Regulation Authority (NRA) and the central government, as well as consent from the governments of local prefectures. In July 2013, the NRA issued more stringent safety regulations to address issues dealing with tsunamis and seismic events, complete loss of station power, and emergency preparedness.

Before a nuclear operator can resume electricity generation, it must apply for permission to restart the reactor. The NRA reviews the restart application and inspects the reactor, potentially requiring the operator to make safety upgrades and complete another inspection.



The suspension of Japan's nuclear fleet resulted in significantly greater dependence on liquefied natural gas (LNG), oil, and coal imports to make up for lost domestic nuclear generation. Japan has limited domestic energy resources and imports virtually all of the fossil fuels it uses. Therefore, Japan is the world's largest importer of LNG and the third-largest importer of coal, behind India and China.

In 2017, natural gas accounted for nearly 37% of Japan’s electricity generation, followed by coal at 33%. LNG and coal imports rose last year as court injunctions delayed the planned restart of some nuclear reactors. Japan’s utilities spent approximately $30 billion each year for additional fossil fuel imports in the three years following the Fukushima accident.



As part of Japan's long-term energy policy, issued in April 2014, the central government called for the nuclear share of total electricity generation to reach 20%–22% by 2030, which would require 25 to 30 reactors to be in operation by then. In 2017, four operating nuclear reactors provided 3% of Japan’s total electricity generation.

Twenty nuclear reactors in Japan have permanently retired in the wake of the Fukushima accident. Out of the remaining fleet of 34 operable reactors, 9 are currently operating. Six others have received initial approval from the NRA, and another 12 units are under review. Nine reactors have yet to file a restart application.

[IsailedawayfromFR]

With the country's dearth of natural resources and massive energy needs, the Japanese continue to be smart about things in its diversification of its energy imports and power generation.  Never rely upon single entities like the EU which is over-reliant on Russian natural gas.

[thackney]

With the country's dearth of natural resources and massive energy needs, the Japanese continue to be smart about things in its diversification of its energy imports and power generation.  Never rely upon single entities like the EU which is over-reliant on Russian natural gas.

  Power generation mix in Europe by fuel in 2016–2017
https://www.powermag.com/the-rise-of-natural-gas-generation-in-europe/?pagenum=2

[The_Reader_David]

Of course they have.  To anyone who is capable of rational risk assessment (a surprisingly rare ability) Fukashima was actually an argument for the safety of nuclear power.  Essentially everything that could go wrong went wrong -- it had outdated safety features that required power to scram the reactor (new reactors have a fail-safe scram that drops the control rods when power is lost, was hit by an earthquake of a greater magnitude than it was designed to withstand, plus the tsunami that killed power to the safety system, and the result was, yes a meltdown of the core, but didn't breach the containment, just ended up on the floor amid rubble, mild contamination of an area around the plant which has been a great nuisance to remediate, but was still remediable.

There is no reason not to restart the reactors with modern safety features.

[IsailedawayfromFR]

  Power generation mix in Europe by fuel in 2016–2017
https://www.powermag.com/the-rise-of-natural-gas-generation-in-europe/?pagenum=2

Guess it surprises me to see such a large swing in hydro power from +20% to now less than 15%.  Unless they are blowing up dams, the only other reason is there are no new installations and the rest of the new energy needs rising are satisfied by other types of power generation so its % share is decreasing.

Unless it is in Greece or Spain, solar in Europe is a joke.

[thackney]

Guess it surprises me to see such a large swing in hydro power from +20% to now less than 15%.  Unless they are blowing up dams, the only other reason is there are no new installations and the rest of the new energy needs rising are satisfied by other types of power generation so its % share is decreasing.

Unless it is in Greece or Spain, solar in Europe is a joke.

Over the year, hydro tends to vary based upon rainfall.  When rainfall is low, many lakes have a minimum level and they cut back water through the turbine.  Don't read too much into just a couple year tracking.  It is rarely steady.

For example:
https://www.energy.gov/sites/prod/files/2017/04/f34/US-Hydropower-Market-Report-2017-Update_20170403.pdf

[IsailedawayfromFR]

Over the year, hydro tends to vary based upon rainfall.  When rainfall is low, many lakes have a minimum level and they cut back water through the turbine.  Don't read too much into just a couple year tracking.  It is rarely steady.

For example:
https://www.energy.gov/sites/prod/files/2017/04/f34/US-Hydropower-Market-Report-2017-Update_20170403.pdf

Well, I had thought pumped water storage was an up-and-coming thing to supply energy when the wind isn't blowing or the sun not shining as the EU continues on its expansion in those types of energy.

[Drago]

"Pumped Hydro" only really works well with nuclear power...late night/low power use time = pump the water back up to reservoir at the top. PG&E uses that method at the Helms project (well, at least until they shut down Diablo Canyon, dumb).

[Joe Wooten]

Unless it is in Greece or Spain, solar in Europe is a joke.

Even in those two nations, it is still a joke

[Joe Wooten]

Of course they have.  To anyone who is capable of rational risk assessment (a surprisingly rare ability) Fukashima was actually an argument for the safety of nuclear power.  Essentially everything that could go wrong went wrong -- it had outdated safety features that required power to scram the reactor (new reactors have a fail-safe scram that drops the control rods when power is lost, was hit by an earthquake of a greater magnitude than it was designed to withstand, plus the tsunami that killed power to the safety system, and the result was, yes a meltdown of the core, but didn't breach the containment, just ended up on the floor amid rubble, mild contamination of an area around the plant which has been a great nuisance to remediate, but was still remediable.

There is no reason not to restart the reactors with modern safety features.

Get your facts straight.
The control rods in both BWR's and PWR's DO NOT need power to insert. You need power to keep them out. They are spring loaded so when power is lost, the rods drop (PWR rods out top) or insert  (BWR, rods come out bottom) automatically. All of the nukes in the earthquake area had already scrammed including all the operating units at Fukushima. All the transmission lines were down, so when you cannot get rid of the electricity, the generator trips off taking the reactor with it. What got to Fukushima was the decay heat of the fuel. Without power, you could not circulate and cool the water. Units 1-4 had isolation condensers with diesel driven refill pumps and the two operating units were on them after they tripped. IC's are passive cooling systems that use natural circulation to run the reactor water through tubes in a huge water tank that vents steam out the side of the containment to carry off the heat. There is enough water in an IC to cool the reactor for about 7-8 hours. Even longer if your pump works to bring in more water. The plants also have technical specifications that prescribe the maximum cool down rate to prevent damage to the reactor. Fukushima started exceeding this cool down rate, so the operators shut the IC's down. The tsunami hit 15 minutes later. Even though the valves can be manually opened, the operators lost their heads and never did. They were overloaded with s the other problems. the decay heat built up, boiled the water in the reactor, popped the safety valves and uncovered the core. Decay heat is about 25 megawatts and falls rapidly off in a few days. At Fukushima, the uncovered core started melting, which melted the control rods, causing even more heat to be generated.

Piss-poor design practices that not even the old AEC would have tolerated. Diesels, batteries and safety related switchgear sited below grade at a sea level plant is stupid, and would never been allowed to happen here.

[Smokin Joe]

"Pumped Hydro" only really works well with nuclear power...late night/low power use time = pump the water back up to reservoir at the top. PG&E uses that method at the Helms project (well, at least until they shut down Diablo Canyon, dumb).

https://en.wikipedia.org/wiki/Bath_County_Pumped_Storage_Station
It has been around for a while. I worked on an archaeological crew in the Lower Back Creek Valley in 1978, before going off to grad school. They were blasting the tunnels through the mountain from the Upper Back Creek Valley then. The whole project was designed to handle peak loads, generating power, and pump the water back up during off peak hours.

[Drago]

Yep, about the same time as Helms (started construction in 1977 & started up in 1985).

http://www.pgecurrents.com/2011/10/17/by-the-numbers-helms-pumped-storage-facility/

[thackney]

"Pumped Hydro" only really works well with nuclear power...late night/low power use time = pump the water back up to reservoir at the top. PG&E uses that method at the Helms project (well, at least until they shut down Diablo Canyon, dumb).

No, it is not limited to nuclear power for practicality.  It is a way to take a base load unit, even coal, and get the power output of the system to swing more with the demand curve.  You can use higher efficiency generation at a constant output and swing the total output as the demand swings.

And they are pulling power from the grid.  There is no need to be directly paired and almost never are built that way.

[thackney]

Get your facts straight.
The control rods in both BWR's and PWR's DO NOT need power to insert. You need power to keep them out. They are spring loaded so when power is lost, the rods drop (PWR rods out top) or insert  (BWR, rods come out bottom) automatically. All of the nukes in the earthquake area had already scrammed including all the operating units at Fukushima. All the transmission lines were down, so when you cannot get rid of the electricity, the generator trips off taking the reactor with it. What got to Fukushima was the decay heat of the fuel. Without power, you could not circulate and cool the water. Units 1-4 had isolation condensers with diesel driven refill pumps and the two operating units were on them after they tripped. IC's are passive cooling systems that use natural circulation to run the reactor water through tubes in a huge water tank that vents steam out the side of the containment to carry off the heat. There is enough water in an IC to cool the reactor for about 7-8 hours. Even longer if your pump works to bring in more water. The plants also have technical specifications that prescribe the maximum cool down rate to prevent damage to the reactor. Fukushima started exceeding this cool down rate, so the operators shut the IC's down. The tsunami hit 15 minutes later. Even though the valves can be manually opened, the operators lost their heads and never did. They were overloaded with s the other problems. the decay heat built up, boiled the water in the reactor, popped the safety valves and uncovered the core. Decay heat is about 25 megawatts and falls rapidly off in a few days. At Fukushima, the uncovered core started melting, which melted the control rods, causing even more heat to be generated.

Piss-poor design practices that not even the old AEC would have tolerated. Diesels, batteries and safety related switchgear sited below grade at a sea level plant is stupid, and would never been allowed to happen here.

Thanks for providing that good summary.

[kidd]

... and would never been allowed to happen here.

US utilities spent an enormous amount of money after Fukishima for beyond-design-basis accident remediation.
And of course the new generation of nuke plants (AP1000) employ passive cooling and can run for many days without any human operators at all

[Drago]

No, it is not limited to nuclear power for practicality.  It is a way to take a base load unit, even coal, and get the power output of the system to swing more with the demand curve.  You can use higher efficiency generation at a constant output and swing the total output as the demand swings.

And they are pulling power from the grid.  There is no need to be directly paired and almost never are built that way.

Yeah, Diablo Canyon isn't "paired" (hundreds of miles away from Helms)...just better to keep the nuke plant at a constant operating level and pull excess power off the grid at night and pump the water back up. Efficiency-wise I would expect nat. gas "peaker" plants to be the cheaper/more efficient  option (over pumped hydro for peak afternoon times).



@thackney

[Smokin Joe]

Yeah, Diablo Canyon isn't "paired" (hundreds of miles away from Helms)...just better to keep the nuke plant at a constant operating level and pull excess power off the grid at night and pump the water back up. Efficiency-wise I would expect nat. gas "peaker" plants to be the cheaper/more efficient  option (over pumped hydro for peak afternoon times).



@thackney

Pumped hydro operates at a net energy loss. (It uses more than it produces).
What it does do well is provide peak load power, and it uses base power that isn't being utilized otherwise during off peak times. Effectively, it is a storage device, converting electrical to mechanical to potential energy, and back, later when it is needed.

[Joe Wooten]

US utilities spent an enormous amount of money after Fukishima for beyond-design-basis accident remediation.
And of course the new generation of nuke plants (AP1000) employ passive cooling and can run for many days without any human operators at all

Yep. I worked on the AP1000 design, mostly for the BOP. The nuke island safety features are excellent. I just wonder why they were not adopted in the earlier generations.
















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