Nature and Man: Hazards, Earthquake & Nuclear energy!

[Asher Kelman]

Levels now reported down to safe zone!

 

[Jerome Marot]

The old rem unit is useful since it has a one to one relationship with 1 rad if all that radiation is absorbed in 1gm of tissue.

rem, röntgen and rad are deprecated as units. The sievert is related to the modern unit (gray) in the same manner as the rem was related to the rad. I strongly advise to use the new units, because serious news reports will use those and conversion is a source of errors (we both got it wrong at some point...). This is also the reason why I listed examples in sievert, so that people get an idea of what the unit means.

I have often seen people getting vallues wrong by a factor of thousand in similar cases for this very reason (and the confusion with the decimal point).

 

[Georg R. Baumann]

If I would be a religious person, I would pray very hard that they can avoid the worst case. Tokyo with it's approx. 36 million people is a sitting duck, no way to evacuate.

Imho, the meltdown risk is increasing by the hour since the first reactor had cooling problems. To me it appears as if they are fighting a lost case. I think from day one that a meltdown is not avoidable and just a matter of time. Another 6.3 quake hit the very area this morning.

I totally fail to understand why they don't encase every reactor block in cement thick enough to do the job for 10-20 years, and learning from the errors of judgement in chernobyl, immediately begin with a steal or similar construction to secure the cement from erosion.

The way they act looks foolish to me, they seem to think they still can control the process and avoid meltdown, I don't think they can.

 

[Doug Kerr]

Hi, Jerome,

8217 microsieverts an hour is 82.17 microrems an hour.

According to my references, 8217 microsieverts per hour corresponds to 821700 microrems per hour (821.7 millirems per hour, 0.8217 rems per hour).

The equivalence I am using is:

1 Sv = 100 rem

thus:

1 μSv = 100 μrem

What am I missing here?

Best regards,

Doug

 

[Jerome Marot]

According to my references, 8217 microsieverts per hour corresponds to 821700 microrems per hour (821.7 millirems per hour, 0.8217 rems per hour).

You are right, but Asher Kelman already corrected my mistake above.

 

[Doug Kerr]

You are right, but Asher Kelman already corrected my mistake above.

Clever of you to notice.

Doug

 

[Asher Kelman]

I totally fail to understand why they don't encase every reactor block in cement thick enough to do the job for 10-20 years, and learning from the errors of judgement in chernobyl, immediately begin with a steal or similar construction to secure the cement from erosion.

The Japanese trust authority. I guess when one is living so close together, it might be a necessary fact of life. The sad irony is that two of the worst atomic incidents in the history of the atomic age are in these islands!

Asher

 

[Jerome Marot]

I totally fail to understand why they don't encase every reactor block in cement thick enough to do the job for 10-20 years.

Probably because if you build an airtight containment around a 50 MW heat source and cubic meters of water, the pressure buildup would blow up the whole contraption after enough energy has built up.

...but I am not a nuclear energy specialist. Undoubtedly, there are people much more competent than I working on the problem all over the world as we speak.

 

[Asher Kelman]

Probably because if you build an airtight containment around a 50 MW heat source and cubic meters of water, the pressure buildup would blow up the whole contraption after enough energy has built up.

...but I am not a nuclear energy specialist. Undoubtedly, there are people much more competent than I working on the problem all over the world as we speak.

One cannot just seal water plus a melted radioactive core. The pressure will be enormous and the vessel will need to be vented.

Water is used to take off heat. The hot water itself has to go to steam and have energy removed by some means. When there's no pumping, then one cools with the water and eventually has to blead of the superheated steam to prevent explosion.

At first, the steam is pretty clean. There may be slight amount of radioactivity as the water and all the structure of the reactor are being bombarded by energetic neutrons. However, as rods get exposed to air when the water boils off, the cladding in what's actually a tube filled with ceramic fused mixtures of uranium (and plutonium in these MOX reactors like reactor #3 . Even when the graphite rods are put in place to slow down the reactor, there's still so much energy produced that cooling is still required. This also applies to storage pools where "spent" rods are being stored. If the pumps stop, the water will hear up and burn the zirconium of the cladding in the tubes and these with water will liberate hydrogen which is of course flammable and can explode!

Now each time there's an explosion, more of the structure that maintains the integrity of the plant is compromised. With each level of new damage, the rods can further deteriorate and iodine and cesium can be leached out from the once safe ceramic core. Now when steam is vented, on purpose to relieve dangerous pressure or in another explosion, the steam now carried progressively more serious radioactive contamination.

So this chain of events will continue to worsen until uninterrupted cooling is established. As of this morning, they discovered the utility of the water pumps of fire engines, but no one had enough fuel to keep them going. Looking ahead, these tactical problems will be solved. There will be some more explosions and the a period of "crossed-fingers rube-goldberg stability. The human tragedy will grow. However miraculous discoveries of buried people alive after all this time will be made.

In the long run, the plants need to be taken apart safely. We need robotics that can do such tasks as each crew that goes in to save the rest of the community will get some significant dose of radiation. Likely, statistically a few more cancers might occur. However, the lethality of the radiation, however frightening it sounds, is trivial compared to the cold, lack of food and having whole towns swept away by the tsunami.

Still, we have to feel for the 50 men working in these terrible conditions and pray for them. The Japanese authorities use terms like "under control" for a fire yesterday when they also said the fire was out, but which is the truth?

Asher

 

[Georg R. Baumann]

The Japanese trust authority. I guess when one is living so close together, it might be a necessary fact of life. The sad irony is that two of the worst atomic incidents in the history of the atomic age are in these islands!

Asher

Sadly, what I predicted 5 days ago is taking place now.

The situation is out of control and we need to expect the worst case now, this is unfortunately only a matter of time.

 

[Georg R. Baumann]

Probably because if you build an airtight containment around a 50 MW heat source and cubic meters of water, the pressure buildup would blow up the whole contraption after enough energy has built up.

...but I am not a nuclear energy specialist. Undoubtedly, there are people much more competent than I working on the problem all over the world as we speak.

The core melt has already started in two reactors. All six reactors will go into that phase rather sooner than later. The timing of such an operation is crucial, and of course, as long as they use tons of boric acid which is a much bigger problem than the relatively small amount of water which is about 12 feet above the fuel.

The effects on the compressive strength of Portland cement directly mixed with boric acid wastes such as reactor waste, borogypsum and sludges were studied. It was found that as the percent of the sludges increase in the cement mixture the compressive strength decreased.

What I would like to know is this, are the rods fully inserted? Control rods are normally hydraulically driven into the core in less than seven seconds in an earthquake event. Once that happened, the reactor produces 3% of heat equivalent compared to full power level.

I would think, that this should be the major question to be asked the japanese authorities over the coming days, as this makes all the difference.

I am more than suspect on the authorities, in fact I do not believe a single word they say since they started to publish the idea of helicopters to be used to cool the systems by dropping water.

Trust me, this is an utterly idiotic suggestion on the same level than to suggest people to crawl under a desk and hold a newspaper over their head in case of a nuclear event.

The cooling systems required are operating with high pressure.

The RCIC system consists of a turbine-driven pump, piping, and valves necessary to deliver water to the reactor vessel at operating conditions.

 

[Georg R. Baumann]

fwiw, my take is this:

- The situation is 100% out of control. - Side note: Not a single TEPCO board member has faced the press to date, one reason is the immense power the nukes lobby has in japan, and other parts of the world!

- Meltdown of six reactors is inevitable

- 50 people are left to deal with a now dysfunctional control system, where before 750 people were required.

 

[Georg R. Baumann]

in case you are interested:

http://www.nytimes.com/2011/03/16/world/asia/16contain.html

http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf

 

[Bart_van_der_Wolf]

What I would like to know is this, are the rods fully inserted? Control rods are normally hydraulically driven into the core in less than seven seconds in an earthquake event. Once that happened, the reactor produces 3% of heat equivalent compared to full power level.

I would think, that this should be the major question to be asked the japanese authorities over the coming days, as this makes all the difference.

Information is lacking, so all we can do is observe from a distance. However, the insertion of the control rods alone is not sufficient.

I am more than suspect on the authorities, in fact I do not believe a single word they say since they started to publish the idea of helicopters to be used to cool the systems by dropping water.

Trust me, this is an utterly idiotic suggestion on the same level than to suggest people to crawl under a desk and hold a newspaper over their head in case of a nuclear event.

Not really. Obviously the helicopters spraying water couldn't help with the cooling of the core, but it could help in reducing the airborne radioactive steam/smoke reaching higher altitude, and thus reduce the contamination area.

Cheers,
Bart

 

[Georg R. Baumann]

Information is lacking, so all we can do is observe from a distance. However, the insertion of the control rods alone is not sufficient.



Not really. Obviously the helicopters spraying water couldn't help with the cooling of the core, but it could help in reducing the airborne radioactive steam/smoke reaching higher altitude, and thus reduce the contamination area.

Cheers,
Bart

They can't Bart...

9:37AM today

The situation at the Fukushima Daiichi nuclear plant remains extremely perilous and seemingly beyond the control of authorities. Staff at the plant were evacuated for a period this morning after radiation levels rose.
A fire broke out at the No 3 reactor, sending a plume of light grey smoke – possibly radioactive steam – above the plant. Helicopters carried containers of water above the complex but were unable to dump them, reportedly due to the high radiation levels.

 

[Don Ferguson Jr.]

The earthquake did not occur along the expected fault and the big one is still gonna happen sometime .
Interesting read :

http://news.nationalgeographic.com/news/2011/03/110315-japan-earthquake-tsunami-big-one-science/

 

[Asher Kelman]

The earthquake did not occur along the expected fault and the big one is still gonna happen sometime .
Interesting read :

http://news.nationalgeographic.com/news/2011/03/110315-japan-earthquake-tsunami-big-one-science/

6:18 PM on March 15, 2011
It appears that the plant withstood a 9.0 earthquake, but the resulting tsunami took out the backup power source. No power for the punmps no cooling big problem.

It looks as if they excavated off the top 60 feet of the buff (see above photo and google earth)to get the plant closer to sea level. The engineers did this (I assume) to reduce pumping cost, less head to pump less power used.

I know hind site is 20/20 but in an earthquake prone country (Japan) and resulting tsunami events, plan on getting the plant above a tsumami flood event. Da. This could be the biggest engineering oversite of all time!!!

They reduced their pump cost by 60 feet but gave up a big part of their island.

Imagine, excavated 60 ft of protection! If that's true it's amazing stupidity!

 

[Georg R. Baumann]

...and the disinformation continues....

According to authorities, there is no reason for concern as the radiation in the 20 km radius would not have exceeded 1.5 mSv... but... this was a PER HOUR exposure!

To put it into perspective, acceptable levels per year for a human are around 1-2 mSv, if they measure 1.5mSv per hour, this means a level of 13.000 mSv per year.

Sigh....How stupid do they think people are?

Further,

AP is reporting a very worrying comment by Greg Jaczko, chairman of the US Nuclear Regulatory Commission: US nuclear agency chief says no more water in spent fuel pool at troubled Japan plant.

Of course, 30 minutes later japenese press agencies claimed this not to be the case, right. However, apparently Jaczko has boots on the ground in Fukushima.

 

[Asher Kelman]

Of course, 30 minutes later japenese press agencies claimed this not to be the case, right. However, apparently Jaczko has boots on the ground in Fukushima.

I think you mean this.

The sooner we have independent analysis by outside scientists we can trust, then the Japanese will have a chance of up to date technical response. So far, there's such a web of face-saving modest reporting, that no decision can be made!

But why just two experts on boiling reactors, I don't know.

Asher

 

[Bart_van_der_Wolf]

The sooner we have independent analysis by outside scientists we can trust, then the Japanese will have a chance of up to date technical response. So far, there's such a web of face-saving modest reporting, that no decision can be made!

I think we need to make a distinction between what appears in the media, and what happens behind the scene. The Japanese government and the local media are unreliable sources (it's a tradition), but there is a huge international effort going on.

BTW the first water sprays have been dropped by helicopters. The first drop seemed to be targeted at the no.3 reactor (with the exposed storage basin), and the following drops to amongst others handle some of the steam that resulted.

One of the problems is the fluctuating radiation level, with peak emissions presumably when another fuel rod bursts in the storage basin which is not enclosed by 2 steel hulls, unlike the reactors themselves. With the roof blown off, steam and smoke from that basin can escape freely into the atmosphere without the usual filtration.

To put some of the factual info in context, have a look at some of the dose examples on Wikipedia.

Cheers,
Bart

 

[Georg R. Baumann]

I think you mean this.

The sooner we have independent analysis by outside scientists we can trust, then the Japanese will have a chance of up to date technical response. So far, there's such a web of face-saving modest reporting, that no decision can be made!

But why just two experts on boiling reactors, I don't know.

Asher

In 1986, Harold Denton, then the NRC's top safety official, told an industry trade group that the

Mark I containment, especially being smaller with lower design pressure, in spite of the suppression pool, if you look at the WASH 1400 safety study, you'll find something like a 90% probability of that containment failing.

Of course, soon after that report, the experts carrousel started all over again with counter reports. ...Same old game....

 

[Georg R. Baumann]

There is some good news, they managed to bring power cable to the reactors, which is the first step required to have the RCIC turbine system working to cool the suckers. Fingers crossed!!!!!!!

 

[Asher Kelman]

I like to look at the positive. We humans have the capacity, after all, to invent solutions. Luckily, the Americans and no doubt the French too are providing , out of the limelight, considerable pressure to be allowed to help out. The most up to date report and analysis comes from The New York Times.

The special problem is the nature of the Japanese society which is highly structured and likes to reach a consensus after a slow process. Added to that the Electric Company is not transparent, (an understatement, in itself). The presence or absence of water in the pools storing spent rods is a prime example of contradictory statements and nuanced news reports. However, with the USA overflight measurements, it's clear that the pools are mostly empty. So progressive damage to the rods is certain and the idea of the rods going critical is no longer far-setched.

Now, the US government has realized the that winds could easily move a plume to the west coast. So our intervention with more aggressive insertion of advice, expertise and resources is going to follow, from self interest, at the minimum, albeit late!

The entire area should be evacuated. They also must attend the needs of the millions of folk trapped as refugees or stuck in their homes with no food or fuel deliveries! This is abandonment! Reminds me of the horrors and incompetence of dealing with the New Orleans flood disaster.

Unfortunately, Obama, with his wet finger in the wind, is also far too cautious to lead in getting the Japanese beyond their face-saving paralysis. Rhetoric does not work with fast neutrons or gamma radiation!

My prediction is that things will now get better as the danger is at our gates and is no longer likely to be a local problem is left to the Japanese courtesy, good manners, slowness in consensus building and deference to authority which is frozen.

So, yes, things will also get worse and frightening, but when the USA wakes up, it does act with vigor. Lets hope it's effective.

Asher

 

[Georg R. Baumann]

Yeehaa?

From what I've heard, it would appear that UK and US rescue teams are being pulled out of Japan.

 

[Asher Kelman]

Slow progress, but at least in the right direction!

A BBC News update indicates the cable is connected to reactor # 2 cooling system and that with debris cleared away, rescue teams are penetrating more damaged areas and food supplies are now reaching the folk!

Asher

 

[Jerome Marot]

From various sources:
-the reactor cores are somewhat safe, event if regular venting due to the faulty cooling imply that some amounts of radioactive material are released over the ocean but
-mox elements are stored in the pool of the 3rd reactor
-active elements from the core are stored together with spent fuel in the pool of the 4th reactor which was undergoing maintenance. Apparently, this practice was criticized by the IAEA. I would say quite rightly so.
-on this type of nuclear plants, the pools are outside the confinement zone. Poor design.
-the pools of the 3rd and 4th reactors have reached boiling temperature, at least around some of the elements. The elements have thus been damaged, producing hydrogen (explosions, fires) and contaminating the pool water.
-the priority is thus to keep those pools as cool as possible and under water, using helicopters if needs be
-damage to the pool structures is not yet assessed.

In short: damaged active elements in boiling pools, the whole open to the outside. This is bad. I sincerely hope they manage to install enough cooling and that the structure holds.

 

[Asher Kelman]

Japan Earthquake Update (18 March 2011, 06:10 UTC)
by International Atomic Energy Agency (IAEA) on Thursday, March 17, 2011 at 10:57pm
Temperature of Spent Fuel Pools at Fukushima Daiichi Nuclear Power Plant - UPDATED

"Spent fuel removed from a nuclear reactor is highly radioactive and generates intense heat. Nuclear plant operators typically store this material in pools of water that cool the fuel and shield the radioactivity. Water in a spent fuel pool is continuously cooled to remove heat produced by spent fuel assemblies. According to IAEA experts, a typical spent fuel pool temperature is kept below 25 °C under normal operating conditions. The temperature of a spent fuel pool is maintained by constant cooling, which requires a constant power source.

Given the intense heat and radiation that spent fuel assemblies can generate, spent fuel pools must be constantly checked for water level and temperature. If fuel is no longer covered by water or temperatures reach a boiling point, fuel can become exposed and create a risk of radioactive release. The concern about the spent fuel pools at Fukushima Daiichi is that sources of power to cool the pools have been compromised.

Concern about spent fuel storage conditions has led Japanese officials to drop and spray water from helicopters and trucks onto Unit 3 at Fukushima Daiichi nuclear power plant (See earlier update).

Japan's Nuclear and Industrial Safety Agency has reported increasing temperatures in the spent fuel ponds at Units 5 and 6 since 14 March. An emergency diesel generator at Unit 6 is now powering water injection into the ponds at those Units, according to NISA.

The IAEA can confirm the following new information regarding the temperatures of the spent nuclear fuel pools at Units 4, 5 and 6 at Fukushima Daiichi nuclear power plant:

Unit 4
13 March, 19:08 UTC: 84 °C

Unit 5
17 March, 03:00 UTC: 64.2 °C
17 March, 18:00 UTC: 65.5 °C

Unit 6
17 March, 03:00 UTC: 62.5 °C
17 March, 18:00 UTC: 62.0 °C

The IAEA is continuing to seek further information about the water levels, temperature and condition of all spent fuel pool facilities at the Fukushima Daiichi nuclear power plant."

This means that we are still not accurately informed as to what is actually happening. Today, the US sent a helicopter and plane over the area as well as predator type vehicles to map the radiation levels round the plants and also to measure the heat patterns. From this the US specialist hope to better predict what is happening inside the stricken reactors. Also, we should know tomorrow whether or not any of the pumps energized by the new cable bringing power back to at least one plant, will help cool the reactor and its storage pool outside.

Meanwhile, there are about 7 thousand dead and another 10,000 missing at the least. Some folk appear to be starving having been shut in or at radiation refugee centers where they have run out of food. So there's a lot more suffering.

Asher

 

[Georg R. Baumann]

Btw. I call this 'goofing around with watering cans' because in deed the units may not cool down for many weeks.

The crucial thing is, the final decision when the coffin comes down should NOT be in TEPCO's or Japan's government responsibility, this should be an international responsibility.

The head of the international watchdog, Yukiya Amano,

"This is not something that just Japan should deal with, and people of the entire world should co-operate with Japan and the people in the disaster areas."

Yes Sir, and it is about time that someone tells Tepco the game is over!

 

[Georg R. Baumann]

This means that we are still not accurately informed as to what is actually happening.

Course not!

IAEA Briefing on Fukushima Nuclear Emergency (17 March 2011, 14:00 UTC)

Unit 4 remains a major safety concern. No information is available on the level of water in the spent fuel pool. No water temperature indication from the Unit 4 spent fuel pool has been received since 14 March, when the temperature was 84 °C. No roof is in place.

 

[Bart_van_der_Wolf]

I keep saying this since day one... sand, cement .... over and out.

If only it were that simple ...

What do you think happens to the cores and the watertable/aquifer when the cores are not cooled anymore? I'm no expert, but a meltdown will most likely contaminate a much wider area and have an impact on many more people/animals than is the case in other scenarios.

I have deep respect for the poor souls that are being sacrificed.

Cheers,
Bart