Nuclear disaster in Japan and wider Nuclear discussion

[flicker]

The world-nuclear-news .org site is probably more scary that the mainstream news, since it is much more succinct and direct with the technical aspects of the issue.
The staff at the sites have their hands full, and having to make judgement decisions on whether to do controlled releases or not - not a position I would like at any time.....

Why oh why are nuclear powerplants built in earthquake danger zones.
We have one in California at Diablo Canyon. Near San Luis Obisbo.

 

[Alpe d'Huez]

I'm generally pro-nukes, but this is awful.

"Before the blast, the reactor in trouble had already leaked radiation: Operators at the Fukushima Daiichi plant's Unit 1 detected eight times the normal radiation levels outside the facility and 1,000 times normal inside Unit 1's control room."

This means anyone working in the control room or anywhere near it are in full body suits, with full decontamination scrub downs between shifts. Brutal working conditions, and highly stressful.

I do not see a Chernobyl type meltdown, and if their cooling systems are on line and they can continue to flood the reactor, they should be able to avoid a melt down of the core. But the damage already could render not only the reactor forever unusable, it could make the entire plant off limits for years. Three Mile Island 2 for example only suffered a partial melt down, and there is very low radiation even in the reactor room today. There has been talk about trying to re-build it, but tearing apart the concrete and metal is likely to release more radiation in the atmosphere.

Another issue here is that many of these older nuclear power reactors (Fukushima was built in 1971, forty years ago) were not built when as much was known about fault lines, nor regulations were as rigid as they are in post Chernobyl and TMI years. Earthquake standards at nuclear power plants are often 7.5, and built to much higher. But who predicted an 8.9 earthquake? Something that happens every half millennium?

(Sorry for the long post. I'm an energy geek, and the missus has a degree in environmental sciences and in grad school).

 

[Le breton]

I do not see a Chernobyl type meltdown, and if their cooling systems are on line and they can continue to flood the reactor, they should be able to avoid a melt down of the core. But the damage already could render not only the reactor forever unusable, it could make the entire plant off limits for years. Three Mile Island 2 for example only suffered a partial melt down, and there is very low radiation even in the reactor room today. There has been talk about trying to re-build it, but tearing apart the concrete and metal is likely to release more radiation in the atmosphere.

Another issue here is that many of these older nuclear power reactors (Fukushima was built in 1971, forty years ago) were not built when as much was known about fault lines, nor regulations were as rigid as they are in post Chernobyl and TMI years. Earthquake standards at nuclear power plants are often 7.5, and built to much higher. But who predicted an 8.9 earthquake? Something that happens every half millennium?

If i remember correctly, not only did the core melt in 3miles island, but it made it part way through the floor!

This will probably be the 2nd worst civil nuclear accident.
Unlikely to get as bad as Tchernobyl because with the collapsed confinment building it can build up pressure anymore and blow radiactivity high up in the atmosphere.

The accident is in one of the plants but further north (12 km) in Daini, there is also serious pb with one of the 4 reactors.

 

[Benotti69]

Another issue here is that many of these older nuclear power reactors (Fukushima was built in 1971, forty years ago) were not built when as much was known about fault lines, nor regulations were as rigid as they are in post Chernobyl and TMI years. Earthquake standards at nuclear power plants are often 7.5, and built to much higher. But who predicted an 8.9 earthquake? Something that happens every half millennium?

i have been wondering why the Japanese would develop such energy in a land so susceptible to earthquakes?

i hope they get them locked down and it does not turn out to be a nuclear disaster, but think it may be time for the Japanese(and the rest of us) to start a real big search for alternative energy sources.

 

[Le breton]

i hope they get them locked down and it does not turn out to be a nuclear disaster, ..........
.

But IT IS A NUCLEAR DISASTER

 

[Alpe d'Huez]

I understand. I always felt (and mostly still do) that nuclear is an excellent mid-term option (20-50 years), but maybe the future of solar, wind, tidal, algae, etc. needs to come quicker than that. While more expensive up front, it's a lot cheaper than this is going to be to clean up and deal with, even being optimistic about the reactor damage. Plus, if an earthquake knocks over a bunch of windmills and solar panels it's an easy and relatively inexpensive fix and barely makes the news.

Reports now say probably a total failure of all cooling systems at Fukushima and a second reactor. Very bad.

 

[Le breton]

I understand. I always felt (and mostly still do) that nuclear is an excellent mid-term option (20-50 years), but maybe the future of solar, wind, tidal, algae, etc. needs to come quicker than that. While more expensive up front, it's a lot cheaper than this is going to be to clean up and deal with, even being optimistic about the reactor damage. Plus, if an earthquake knocks over a bunch of windmills and solar panels it's an easy and relatively inexpensive fix and barely makes the news.

Reports now say probably a total failure of all cooling systems at Fukushima and a second reactor. Very bad.

If you look on google map you will see that the location right on the shore and the lower population density around there ( mountainous area) should mitigate the damage.

Built in 1971 that power plant was on its last leg, it had very little commercial value in fact!!! Also only around 500MWe, hence probably only 1/2 as much nuclear fuel as Tchernobyl

Of course the opponents of nuclear energy will exxaggerate things just like proponents, TEPCO and others will try to do the reverse.

 

[Alpe d'Huez]

Agree. It's a shame the extremes always scream the loudest.

If i remember correctly, not only did the core melt in 3miles island, but it made it part way through the floor!

This will probably be the 2nd worst civil nuclear accident.

TMI did not melt through the floor. What happenedis that engineers there got conflicting readings when a valve stuck open, and overrode the emergency cooling system. When that happened the core partially melted instide the reactor chamber itself, and a bunch of sludge ended up solidified at the bottom of the chamber. As all this happened a great amount of steam released in the reactor room, which was partly radioactive and that turned to water, this water sat and contaminated the floor, fairly permanently.

Here is an outstanding PBS documentary on Three Mile Island.

The Simi Valley sodium reactor leak actually released more radiation into the atmosphere than TMI. Maybe 200 times more. But very few people even know the place exists, let alone about the accident.

Excellent video here, courtesy of the History Channel.

 

[Le breton]

Agree. It's a shame the extremes always scream the loudest.



TMI did not melt through the floor. What happenedis that engineers there got conflicting readings when a valve stuck open, and overrode the emergency cooling system. When that happened the core partially melted instide the reactor chamber itself, and a bunch of sludge ended up solidified at the bottom of the chamber. As all this happened a great amount of steam released in the reactor room, which was partly radioactive and that turned to water, this water sat and contaminated the floor, fairly permanently.

Here is an outstanding PBS documentary on Three Mile Island.

The Simi Valley sodium reactor leak actually released more radiation into the atmosphere than TMI. Maybe 200 times more. But very few people even know the place exists, let alone about the accident.

Excellent video here, courtesy of the History Channel.

Thanks for the links, I'll look at them later, time to go for a ride.

I thought there was controversy still about whether that sludge made it partly through the floor, I'll watch your PBS video.

Earlier I was talking about civil nuclear energy, I don't know if that should include accidents such as SIMI or the many accidents which occurred in the defunct Soviet Union.

 

[rhubroma]

This is a clear case of the hubris of post-industriallized man. In Italy there is a long history of anti-nuclear power sentiment, for the simple reason that many Italians are scared to death of the prospect. Thus while there were once reactors in the Boot, a national referendum after Chernobyl shut them down. Often they have been viewed as irrational and paranoid, however, the current situation in Japan is a call for universal reflection.

The pundits of nuclear energy point out that just over the French border there are 50 reactors so Italy isn't safe anyway. However there is a principle here, which can't be justified with such a logic. Nuclear energy creates lethal radioactive waste that has to be dealt with some way within the terrain and no truly satisfactory solutions have thus far been found. There are huge business interests behind nuclear energy that work behind the scenes to push the competition (current or in the future) out of the market, though this never gets much press, even within the political debates. Then, of course, there are the natural disaster risks that Japan (though Italy is also a seismic zone) has horrifically reminded us to be an all too serious reality. Japan has 55 nuclear reactors and a further 2 are under construction.

In la Repubblica today it has been reported that at the Fukushima reactor one of the diesel pumps that provides the facility with water was damaged by the quake. The problem was fixed, however the situation remained critical, so Hillary Clinton had to refurnish the power plant with a liquid cooler from a US base. This still didn't bring the reactor back under control, because it seems as if the cooling system of a second reactor was also damaged and, within the former, according to unconfirmed reports, a quantity of radioactivity leaked out. What's certain, however, is that in the control room of the first reactor the radioactivity, despite that the cooling down of the bars has recommenced, results 1000 times higher than normal levels and the Japanese government has thus evacuated citizens within a 10 kilometer radius.

A second plant near Fukushima, the Daini facility, has cooling problems with 3 of its reactors, the internal pressure there is so high that if methods to bring it down prove unsuccessful, then the technicians will be forced to release some of the radioactive gas into the environment. There was also a fire in the Onagawa plant, however this was rapidly put out.

In any case there is a red alarm situation. Even if the various immediate problems are placed under control, there will still be a long verification process to make sure that the quake didn't damage the structures of the plants themselves. This is a long process. In 2007 an earthquake hit the Niigata plant near Tokyo, which is the world's largest, and this resulted in a small leek of radioactivity, while the plant was closed for two years.

The protect engineers build the nuclear power plants to withstand a certain magnitude of earthquake, yet this tolerance can't be infinite. In the Niigata case the center was built to withstand a quake measuring 6 on the Richter Scale. The problem was that the 2007 quake measured 6.8. On the Richter Scale for every .1 increase in magnitude you have a quake that's 30 times more powerful. Consequently if Fukushima was built to withstand a 7 magnitude earthquake, yesterday’s measured 8.9, so you have a quake that was nearly 1000 times more powerful than the facility's intended tolerance margin.

And if the epicenter of yesterday's quake had been at Fukushima, instead of off shore?!!

I don't see how the world can continue to feel safe with the current distribution of nuclear power plants, and furthermore it makes you wonder about the folly of human industry at times. It's madness.

There needs to be now serious political and industry debates about the future of nuclear electric power in regards to investing in environmentally clean alternatives. However I fear that not even this will bring back some sanity to those humans in charge of making the decisions that effect us all.

 

[python]

just yesterday i thought things aren't as serious, today i hear more alarming news. the collapse of the containment building at unit #1 is as serious as one can't plan for.

one of the problems i am told is that the reactors on this site are of bwr type - a boiling water reactor - where the water of the primary cooling loop (unlike the pwr, pressurized water reactor) is also directly used to generate steam that drives steam turbines.

in other words, this type of reactor has one less barrier to radiation than the most prevalent current design - pwr - and is therefore less safe by design.

but of course, you wont read this anywhere.

 

[rhubroma]

just yesterday i thought things aren't as serious, today i hear more alarming news. the collapse of the containment building at unit #1 is as serious as one can't plan for.

one of the problems i am told is that the reactors on this site are of bwr type - a boiling water reactor - where the water of the primary cooling loop (unlike the pwr, pressurized water reactor) is also directly used to generate steam that drives steam turbines.

in other words, this type of reactor has one less barrier to radiation than the most prevalent current design - pwr - and is therefore less safe by design.

but of course, you wont read this anywhere.

La Repubblica is, of course, a left wing newspaper, so I'm aware that they have some preconceptions and fears about nuclear power (being an Italian daily especially that are also based on an ideological position) and thus may be reporting what many other dailies, for equally biased interests, are less willing to communicate to their readership at this point. This is how your last statement resonated with me.

However, all of this is somewhat irrelevant when you think about the last statements of my previous post. In other words, no matter what your political viewpoint is on nuclear energy, only the foolish or the blind would allow themselves to not be called to reflection.

I'm fine with those fears expressed in la Repubblica, but even among the more pro-nuclear and pro-business sympathizers, you can't deny that this is a scary prospect in terms of the real safety of the industry, and it's engineering practices, with respect to human civilization.

 

[Alpe d'Huez]

It becomes an issue of compromise and practicality though. What do you do?

• Drill for, and use more oil/natural gas? All kinds of problems with this (limited, must deal with Middle East instability, polluting), but its what the US mostly does. Japan imports nearly all of it's oil from abroad.

• Mine for, and use more coal? Bad pollution, but cheap. Another thing the US mostly does.

• Build-up nuclear power, which is risky, expensive at first, but efficient.

• Build more dams, which isn't easy, nor cheap, nor great for the environment.

• Build-up alternative power (wind, solar, bio) and pay about 50% more energy bill for the next 20 years.

• Travel less, use less power (eat more cold or raw food, keep your home cold in the winter, hot in the summer, line dry all clothes, etc.) no fun at all.

What do you choose? Because you can't have it all.

This chart is based around the United States, but gives a very good overview to usage complications.

Japan uses about 15% of it's energy from Nuclear. It's been up to 23% in the past. Think of the difficulties of shutting even just half the power plants down.

 

[Cobblestones]

Is it clear why the explosion occurred? Was it the pressure vessel bursting? Or was it maybe a hydrogen explosion? Anyway, the presence of Cs and I points to at least some ruptured fuel rods (don't want to use the term meltdown yet). Hopefully this can be controlled before it gets worse.

 

[python]

Is it clear why the explosion occurred? Was it the pressure vessel bursting? Or was it maybe a hydrogen explosion? Anyway, the presence of Cs and I points to at least some ruptured fuel rods (don't want to use the term meltdown yet). Hopefully this can be controlled before it gets worse.

nothing is clear yet (one wonderswhy ) but the most probable cause of the explosion is an uncontrollable rise of pressure inside the containment building. the environment inside is mostly air/steam mixture. I'm 90% sure.

the building has a series of pressure reducing arrangements/systems that likely failed.

the first one is air cooling units that have integrated radiation filtering. these units rely on emergency power which apparently was available for only 7 hours
(because emergency diesel generators/batteries ran out of juice in the absence of the external grid power and the tsunami damage.

the second pressure reducing system is containment spay. It's basically a shower mounted in the containment dome. But again, the spay pumps need electricity that apparently was lacking for a while.

the reactor vessel itself is safe as far as i understand. the last barrier to radiation - the nuclear fuel rods themselves - are safe too, unless they completely lost control of cooling, which i doubt very much, as by design, if there is loss of inventory the reactor will stay submerged and the open containment will help remove the residual heat. ..but it will spew more radioactivity.

 

[Benotti69]

It becomes an issue of compromise and practicality though. What do you do?

• Drill for, and use more oil/natural gas? All kinds of problems with this (limited, must deal with Middle East instability, polluting), but its what the US mostly does. Japan imports nearly all of it's oil from abroad.

• Mine for, and use more coal? Bad pollution, but cheap. Another thing the US mostly does.

• Build-up nuclear power, which is risky, expensive at first, but efficient.

• Build more dams, which isn't easy, nor cheap, nor great for the environment.

• Build-up alternative power (wind, solar, bio) and pay about 50% more energy bill for the next 20 years.

• Travel less, use less power (eat more cold or raw food, keep your home cold in the winter, hot in the summer, line dry all clothes, etc.) no fun at all.

What do you choose? Because you can't have it all.

This chart is based around the United States, but gives a very good overview to usage complications.

Japan uses about 15% of it's energy from Nuclear. It's been up to 23% in the past. Think of the difficulties of shutting even just half the power plants down.

all the above points are do able it just becomes that people get too comfortable with their heating, wanting to wear nothing but a t-shirt inside int he winter and then they want the air conditioning in the summer.

Use cars less. walk to shops. let kids walk to school etc..

we are lazy, leaving lights on leaving appliances plugged in etc..

nuclear is not a solution imo if the risk from a leak is so great.

 

[Ferminal]

As far as I know the "explosion" hasn't changed the situation of the actual reactor at all? I don't know much though, obviously not as much as the major news organisations who are leading with it.

Nuclear power is simply a reality for some countries, some of us more spread and better naturally endowed nations will not need to go down that route, but it is an absolute necessity looking at the near future for countries like China and India to have nuclear power as part of their electricity mix. We can either have them build modern reactors, or everyone can just put all their eggs in the "clean coal" basket...

 

[Cobblestones]

nothing is clear yet (one wonderswhy ) but the most probable cause of the explosion is an uncontrollable rise of pressure inside the containment building. the environment inside is mostly air/steam mixture. I'm 90% sure.

the building has a series of pressure reducing arrangements/systems that likely failed.

the first one is air cooling units that have integrated radiation filtering. these units rely on emergency power which apparently was available for only 7 hours
(because emergency diesel generators/batteries ran out of juice in the absence of the external grid power and the tsunami damage.

the second pressure reducing system is containment spay. It's basically a shower mounted in the containment dome. But again, the spay pumps need electricity that apparently was lacking for a while.

the reactor vessel itself is safe as far as i understand. the last barrier to radiation - the nuclear fuel rods themselves - are safe too, unless they completely lost control of cooling, which i doubt very much, as by design, if there is loss of inventory the reactor will stay submerged and the open containment will help remove the residual heat. ..but it will spew more radioactivity.

I don't agree. Emergency pressure release should not and does not require electrical power. Now, a valve can still get stuck but you would expect some redundancy. If pressure buildup exceeds the capability of the vessel to hold it in, the emergency release has to kick in.

Emergency release of pressure is always preferable to uncontrolled explosive release because you cannot know what might get damaged in the process. Maybe the pressure containment was weaker than thought, or the emergency release was stuck or had a wrong set point or was disabled on purpose.

The detection of radiation from Cs and I is troublesome. Normally, nuclear fuel (were these fission fragments are produced) are cladded with Zr and/or other materials such that fission fragments do not escape. Fuel rods can crack when not cooled properly, at which time fission fragments can escape. It seems that some cracking has occurred and some radioactivity has escaped into the atmosphere either through leaks or emergency release.

What might also happen is hydrolysis (cooling water splits into hydrogen and oxygen) either by radiolysis or reaction of very hot steam with the Zr cladding. In either case hydrogen is produced, which in the presence of oxygen can become highly explosive. I hope this is not what happened in Japan.

 

[auscyclefan94]

all the above points are do able it just becomes that people get too comfortable with their heating, wanting to wear nothing but a t-shirt inside int he winter and then they want the air conditioning in the summer.

Use cars less. walk to shops. let kids walk to school etc..

we are lazy, leaving lights on leaving appliances plugged in etc..

nuclear is not a solution imo if the risk from a leak is so great.

Agreed, also required a lot of water to power a nuclear power plant which we do not have as much as we use to. The nuclear plant possibly over heating with radioation leaks is a very scary prospect not just for Japan but for the whole planet.

 

[Ferminal]

Agreed, also required a lot of water to power a nuclear power plant

As for any thermal power plant... except open-cycle gas?

3 people reported to have shown in hospital with abnormal radiation levels.

Does anyone know if they are writing the reactors off by flooding them with boronic acid/sea water? Seems like a bit of a "last resort" solution.

 

[rhubroma]

all the above points are do able it just becomes that people get too comfortable with their heating, wanting to wear nothing but a t-shirt inside int he winter and then they want the air conditioning in the summer.

Use cars less. walk to shops. let kids walk to school etc..

we are lazy, leaving lights on leaving appliances plugged in etc..

nuclear is not a solution imo if the risk from a leak is so great.

Agreed too. Humans are not gods, they are fallible. The risks of nuclear energy when set against the benefits, when the benefits really have to do with maintaining our modern way of life for all the reasons you mention, make it that I would willingly give up the appliances to avoid a meltdown.

Not all feel this way though.

 

[Le breton]

As for any thermal power plant... except open-cycle gas?

3 people reported to have shown in hospital with abnormal radiation levels.

Does anyone know if they are writing the reactors off by flooding them with boronic acid/sea water? Seems like a bit of a "last resort" solution.

that reactor, No 1, was written off hours ago I would think!. It's not worth much anyway, 40 years old, built in 71, only 473 MWe.

Glad to see that they have boron available! Also that they can pump sea-water. They might be on track to successfully cool the core ( might take 1 week).

 

[python]

I don't agree. Emergency pressure release should not

if you don't agree how the actual plant was and is designed but rather how it should work you need to send your ideas to the appropriate nuclear authorities.

 

[Le breton]

if you don't agree how the actual plant was and is designed but rather how it should work you need to send your ideas to the appropriate nuclear authorities.

Unit No 1 is a BWR-3. It apparently does not have passive pressure release as more recent models do.
Here is good source
2011 earthquake events This section documents a current event. Information may change rapidly as the event progresses.

After the March 11, 2011 earthquake, Nuclear Engineering International reported that units 1, 2 and 3 were automatically shut down, and units 4, 5 and 6 were already in maintenance outages.[5] Diesel generators installed to provide backup power for the cooling systems for units 1–3 were damaged by the tsunami;[6] they started up correctly and then stopped abruptly about 1 hour later.[7] In Japan a nuclear emergency is declared upon cooling problems. Because cooling is needed to remove residual reactor heat, a nuclear emergency was declared—for the first time—when the diesel engines failed. Batteries, which last about eight hours, were being used to power the reactor controls and valves during the electrical outage.[8][9][10] Japanese ground forces were said to be trucking generators and batteries to the site.[11]

An evacuation order was issued to people living within 3 kilometres (1.9 mi) of the plant, affecting approximately 5,800 residents. People living less than 10 kilometres (6.2 mi) from the power plant were advised to stay indoors.[12] Later the evacuation was expanded to a 10 kilometres (6.2 mi) radius, and then to a 20 kilometres (12 mi) radius.[13][14][15]

On March 12, 2011, after midnight local time, it was reported that the Tokyo Electric Power Company was considering venting hot gas from the reactor vessel number 1 into the atmosphere, which could result in the release of radiation.[16] The Tokyo Electric Company reported that radiation levels were rising in the turbine building for reactor 1.[17] At 2:00 JST, the pressure inside the reactor containment was reported to be 600kPa (6 bar or 87 psi), 200 kPa (2 bar or 29 psi) higher than under normal conditions.[7] At 5:30 JST the pressure inside Reactor 1 was reported to be 2.1 times the "design capacity",[18] 820 kPa (8.2 bar or 120 psi).[19] At 6:10 JST, the IAEA reported that unit 2 was also experiencing cooling problems.[20]

Wikinews has related news: Earthquake-damaged Fukushima nuclear power plant triggers evacuation
To reduce mounting pressure potentially radioactive steam has been released from the primary circuit, into the secondary containment.[21] On March 12, 2011 at 6:40 JST, Chief Cabinet Secretary Yukio Edano stated that the amount of potential radiation would be small and that the prevailing winds are blowing out to sea.[22] Radiation levels recorded by the plant control room were reported to be approximately 70 microsieverts (i.e., 7 millirem) per hour.[23] Radiation levels measured at a monitoring post near the plant's main gate were reported to be more than eight times above normal.[24][25] In a press release at 7 am (local) March 12, TEPCO stated "Measurement of radioactive material (Iodine, etc.) by monitoring car indicates increasing value compared to normal level. One of the monitoring posts is also indicating higher than normal level."[15] At 13:30 local time, radioactive caesium was detected near reactor 1.[26][27] TEPCO reported that at 15:29 JST (06:43 GMT) radiation levels at the site boundary exceeded the regulatory limits.[28] Fuel rods may have been exposed to the air.[29]

The Prime Minister of Japan, Naoto Kan, visited the plant for a briefing on March 12, 2011.[30] The Tokyo fire department sent a special nuclear rescue team to Fukushima.[31]

Over 50,000 have been evacuated during March 12.[32]

[edit] Explosion and collapse of the outer structure
NHK Sōgō channel TV program screen shot image depicting before and after a explosion of Fukushima I Unit 1 reactor, The news was broadcast at 18:00 (JST) 12 March 2011.At 16:30 JST (7:30 GMT) on March 12, there was an explosion at the plant.[33] At 17:00 JST (0800 GMT), Fox News Channel reported the explosion and a plume of "white smoke" rising above the plant.[34] At 17:03 JST (08:03 GMT) BBC News reported that Japan's NHK TV reported the explosion as "near" the plant, and that four workers were injured.[35] At 18:43 JST (9:43 GMT) officials had confirmed that an explosion has occurred at the nuclear plant.[35] Chief Cabinet Secretary Yukio Edano indicated -according to a Reuters report of 21:36 JST (7:36 ET), that the concrete outer structure had collapsed as a result of a hydrogen explosion triggered by falling water levels. At 19:37 JST (10:37 GMT) Reuters reported that Mr Ian Hore-Lacy, communications director at the World Nuclear Association, considered the same cause.[36] Edano further indicated that the container of the reactor had remained intact and there had been no large leaks of radioactive material.[37] An increase in radiation levels has been confirmed following the explosion.[38][39] ABC (Australia) reported "According to the Fukushima prefectural government, the hourly radiation from the plant reached 1,015 microsievert [0.1015 rem] - an amount equivalent to that allowable for ordinary people in one year."[40][41]

The Guardian reported at 17:35 JST (8:35 GMT) that NHK advising residents of the Fukushima area "to stay inside, close doors and windows and turn off air conditioning. They were also advised to cover their mouths with masks, towels or handkerchiefs" as well as not to drink tap water.[42] At 19:07 JST (10:07 GMT) Reuters reported that the exclusion zone has been extended to 20 kilometres (12 mi) around the plant.[43] BBC correspondent Nick Ravenscroft was stopped 60 kilometres (37 mi) from the plant by police.[44] Air traffic has been restricted in a 20 kilometer radius around the plant, according to a NOTAM[45]. The BBC has reported as of 22:49 JST (13:49 GMT) "A team from the National Institute of Radiological Sciences has been despatched to Fukushima as a precaution, reports NHK. It was reportedly made up of doctors, nurses and other individuals with expertise in dealing with radiation exposure, and had been taken by helicopter to a base 5 km from the nuclear plant." [35] The BBC has reported as of 23:27 JST (14:27 GMT) "More than 300,000 people have now been evacuated from homes in northern Japan and that number will rise as the government increases the exclusion zone around the Fukushima nuclear power plant" [35]

Yaroslov Shtrombakh, a Russian nuclear expert, said he did not believe that a Chernobyl-style disaster will occur, citing the differences between the designs of the Chernobyl Nuclear Power Plant and the Fukushima I Nuclear Power Plant. He speculated that any nuclear material released during the incident would likely be confined to the grounds in and around the power plant.[46]

At 21:37 JST (12:37 GMT) Reuters reported that TEPCO planned to cool the leaking reactor with sea water, using Boric acid to prevent a criticality accident. The sea water would take five to ten hours to fill the reactor core, after which it would require seawater cooling for around ten days.[37]

At 23:43 JST (14:43 GMT) BBC News stated that the four workers that were injured in the blast at the Fukushima No. 1 nuclear plant were conscious and their injuries were not life-threatening. [35] This was followed at 23:59 JST (14:59 GMT) with BBC advising both Kyodo and NHK reporting at least three residents evacuated from a town near quake-hit Fukushima No. 1 plant have been exposed to radiation. [35]

At 22:53 JST (13:53 GMT) Tokyo Broadcasting System (TBS) has reported that "Fukushima Daiichi nuclear power plant after the explosion, all three patients and hospital staff received a welfare check Hutaba radiation exposure, had found that the amount of exposure that need to be cleaned up.　According to Fukushima Prefecture, to evacuate 30 people staff and 60 patients of the hospital welfare Hutaba exploded reactor of the nuclear Fukushima Daiichi while they were waiting for the helicopter rescue of the SDF in ground school Hutaba. One out of three people who check it for sure, "10 million counts per minute" amount of exposure was found. The other is that two people were detected radiation exposure of 40,000 counts per minute, 30,000. According to experts, this radiation exposure is that it is in need of decontamination.　That was in need of decontamination exposure to all three received the check may have been exposed to all the people 90.　The exposure to high Hutaba from the Fukushima Daiichi nuclear power plant is located about 3.5 km." [47]

 

[Cobblestones]

if you don't agree how the actual plant was and is designed but rather how it should work you need to send your ideas to the appropriate nuclear authorities.

No, I disagree with your assertion that emergency pressure relief requires electricity.

Ferminal: no need to have boronated water. The control rods are all in. There's no neutrons in the core which need to be absorbed. The nuclear chain reaction was stopped seconds after the earthquake occurred.

The problem is not the availability of cooling water. It's the lack of power to get it flowing through the core. All reactors were shut down right after the earthquake, then the backup diesels got killed by the tsunami and the connection to the grid got severed. Only battery power left, but that's not enough to keep the large pumps running.

If just the backup diesels had been placed on higher ground such that they wouldn't have been destroyed by the tsunami. I think that would have prevented most if not all problems. Yesterday, I thought maybe a ship could get there and the ship's diesel might provide electricity for the cooling pumps. I wonder if that was ever considered.

ETA: anyway, since the explosion seems to be confirmed as a hydrogen explosion, all the points about pressure and pressure release seem to be moot.