Nature and Man: Hazards, Earthquake & Nuclear energy!

[Asher Kelman]

Hopefully, the folk can find the references to reliable sources helpful. The human tragedy is enormous. The pain of missing over 10,000 people even after 7,000 dead are counted is far beyond heartbreaking. My reference points for my own remarks are grounded in my training and experience as a Radiation Oncologist. Furthermore I have first-hand knowledge of nuclear plant and pool inspection as well as safety mechanisms and review of thousands of incidents at US nuclear plants. I look at this from a point of view of the tragic consequence and the facts so we understand where we stand.

Right now, there is sufficient expertise coming in to get independent radiation measurements that practical solutions will be found. As I said, there might be up to about 150 severely ill or will die from radiation exposure. The political ramifications will come after we deal with the needs of immediate safety and humanitarian aid for those 100,000 or more displaced with scant food and heat. However, that's just beyond the scope of OPF.

Asher

 

[Asher Kelman]

I hope we will see progress by the end of tomorrow with some pumps perhaps working. The worse worries seem to be with storage pools 3 and 4 for which there's scant knowledge about water levels and a crack in the concrete is likely. The International Atomic Energy teams in Tokyo report no significant Cesium 137, (behaves like Potassium in the body, very energetic and a half life of 30 years) nor of Iodine-131, (goes to the thyroid gland to make thyroid hormone). Strontium 90 was not reported.

In the coming days teams might get gradually closer to the damaged reactors but they seem to be checking for the safety of large cities first. What's great about this is that they will thus, calm the population and allow food delivery and work to restart where it was stalled. If this works in the cities further away, that normality should help get food organized to be sent to the damaged regions where folk are really starving. Over 1.0-1.5 million are without running water. The cold has effected the viability of the elderly and infirm and is complicated by limited food.

The latest report is here.

More elderly people are at risk of dying from cold and starvation, right now, than from radiation. Hopefully, this can be remedied as the major cities get new confidence as accurate safe levels are continually updated in an open manner. My impression is that a mood favoring international sharing of information and access to the latest readings and past data, is moving in the right direction.

The problem with pools #3 and #4 is that there is no current technology worked out for dealing with rods with the cladding damaged and the ceramic materials aggregated together become re-critical. Water, slowing down the neutrons, increases efficiency of capture and then worsens the damage going on! These new, (amazingly-unimagined), problems will be classic cases nuclear scholars will discuss for decades to come. Engineers all over the world will learn a lot from the unfortunate accidents in Japan and no doubt make plants safer for the rest of us. Right now, the best brains are being tested.

Let's hope tomorrow will be a better day!

Asher

 

[Asher Kelman]

Guys,

18 posts have been located in our repository. Folk can say what they like but there will be housekeeping in this thread to keep focus on the facts and consequences to life in Japan. During the time of this disaster I have done a large amount of new photography. Two major shoots in New York and in Los Angeles. It's so easy to get lost in one's own "important" work, that what happens thousands of miles away seems of low importance.

If we don't address this, then how will we be able to talk to our children about values and choices? Hopefully, what's presented here in OPF will allow a lot of you a quick update. It's not just a matter of knowing and being able to have a meaningful conversation. It's far more than that. It's about our own humanity and character. I spoke to a former Consul from the U.K. who insisted there's was "nothing of significance" to be concerned about in the Japanese reactors! I knew then that we are in more trouble than I had imagined.

I hope more 2-second photos and sound-bites get in the news, as that's all might catch the public's brief attention span.

Asher

 

[Don Ferguson Jr.]

I do not think this could happen in this matter with plants in America . For one we do not have six plants all together and two we would had more quickly got electrical pumps up and running and power restored .

Yes. San Onofre and Diablo Canyon both say they have gravity-based backup cooling systems as well as emergency diesel generators. Also, San Onofre is protected by a 30-foot-tall reinforced "tsunami wall," and Diablo Canyon sits atop an 85-foot cliff. "If a tsunami reached that high, California would have much bigger problems than a busted reactor," Helman says.

http://theweek.com/article/index/213181/what-happens-if-a-japan-sized-earthquake-hits-california

Indian River a three-unit nuclear power plant on the Hudson River is the most worrisome one I read.

I do pray for the Japanese people that all gets better though this weekend with power being restored and hopefully they can cool the cores.

 

[Asher Kelman]

Electricity is patched now to reactor's 5 and 6, which although not damaged, have temp problems. Then it will be connected to reactor # 2 which does not have the walls blown off so they don'y know what's going on inside. If the pumps work, great! If not new ones will have to be fitted. Unfortunately, this is not a robotic job as yet!

#4 storage pool remains a major concern as it may have no water and a cracked concrete structure. So perhaps sand and boron might be poured in as a temporary stop gap measure to shield and slow things down.

"At the request of the Japanese military, a Massachusetts company, iRobot, said it put four robots on a plane for Japan on Friday. Colin Angle, the chief executive, said it had sent two small robots that could measure radiation levels close to the reactors and two larger ones that could pull hoses to spray water on the fuel rods.

He said Japanese soldiers could operate the robots from a protected vehicle."

Slow but progress!

No serious radiation outside of 28 KM but no detailed reports on the poor people. Nothing on shielding of the workers! The volunteer workers are shown with red helmets but no suits or breathing apparatus or gas type masks with cylinders for absorption of the radioactive particles.

Asher

 

[fahim mohammed]

I, too, feel for the people of Japan; in this time of terrible diasaster that has struck their country.

I pray for the Japanes people and their safety, well being. Them and their country.

However, I do believe that OPF should have moved this thread to its appropriate place..diaster/strife/targedy..section.

This is not the right place..the right category to discuss this human tragedy.

There is a place reserved at OPF for such isuues.

That is my understanding.

 

[fahim mohammed]

Thank you.

Let's hope the minds of mankind around the world get together and find a timely and successful
solution to this tragic accident.

Concurrently, I pray that solutions and lessons are learned and applied to minimize ( as much as is humanly possible ) such catastrophic accidents in the future.

For all our sakes..and for our coming generations. Else they shall never forgive us nor pray for us.

 

[Asher Kelman]

Around the stricken reactors, spinach and milk are contaminated and also traces of radioactive Cesium-137 and Iodine 131 are on the soil raising issues for agricultural production, so the limits of this are being evaluated. Tokyo is essential free and clear.

The places in between are now being tackled by IEEC inspectors and Japanese government workers.

Still no word of pumps working in reactor #2. Reactors #5, #6 have had roof vents made to forestall explosions and water is circulating although temps have risen a little.

No hard knowledge of interior conditions of 1,2 and 3 or pools espec #4.

Many more firefighters hosing down reactors.

Massive quantities of boric acid being imported from South Korea.

Sprint of the Prime minister: admits slowness in response and getting out info but vows to lead Japan and rebuild her from scratch!

Latest IEEC report here.

Asher

 

[Asher Kelman]

Why the above ground unprotected pools?

One might wonder, "Why on earth would pools for storing spent fuel or the fresh fuel when the reactor was serviced, would be two stories up in the sky?"

Well, NY Times has illustrations to explain here.

Essentially, it would require a massive hole to fully bury the pools with the Torus (used to cool the steam after it did its work driving electricity-generating turbines).

Asher

 

[Jerome Marot]

One might wonder, "Why on earth would pools for storing spent fuel or the fresh fuel when the reactor was serviced, would be two stories up in the sky?"

I certainly did not wonder about that. It is pretty obvious that the reactor is serviced by the top, and that the pools are next to the service opening.

OTOH, what I find appalling is that this system was kept unchanged with knowledge gained in the 40 or so years since the plants were built. Keeping fuel rods under a structure which can at best be described as a light cover is bad practice. And keeping 1500 rod elements in the pools of reactor 4 is not what was intended when the plants were designed.

 

[Asher Kelman]

I certainly did not wonder about that. It is pretty obvious that the reactor is serviced by the top, and that the pools are next to the service opening.

OTOH, what I find appalling is that this system was kept unchanged with knowledge gained in the 40 or so years since the plants were built. Keeping fuel rods under a structure which can at best be described as a light cover is bad practice. And keeping 1500 rod elements in the pools of reactor 4 is not what was intended when the plants were designed.

Jerome,

I think you have hit the nail on the head. We are not responding sufficiently to knowledge and improving what we do. Newer reactors are better designed but still not standardized. Also, we leave too much to companies instead of making more prudent international standards at every stage. My feeling is that nations should run plants with international supervision and updated rules for design, standardization, maintenance, reporting, hazards and rescue response.

If we must have these reactors, then they shouldn't be under the whim and will of privateers rather under the discipline of best practice which should evolve.

Asher

 

[Asher Kelman]

Fukushima update

• Reactor 1: Fuel rods damaged after explosion. Power lines attached. [I]Pumps not attached or tested.[/I]
  
  
• Reactor 2: Damage to the core, prompted by a blast, helped trigger raising of the nuclear alert level. Power lines attached Pumps not attached or tested.
  
  
• Reactor 3: Contains plutonium, core damaged by explosion. Fuel ponds refilled with water in operation
  
  
• Reactor 4: Hit by explosion and fire, temperature of spent fuel pond now said to have dropped after water spraying
  
  
• Reactors 5 & 6: Temperature of spent fuel pools now lowered after rising dangerously high. Diesel generators powering cooling systems

Source

Sadly, it looks like the number of souls lost from the Tsunami that followed the 9.0 earthquake will top 20,000. Although there are traces of isotopes in some foods, they are being discovered and segregated. No health consequences are likely from this apart from terrible economic loss to farmers.

Mother nature is still more of a demon than we are. The earthquake that flattened 1923 all wooden Tokyo took over 140,000 people. It was even far worse for some non-native Japanese there than that number would make you imagine. Maybe we are learning a little.

Asher

 

[Asher Kelman]

To clarify the different parts of the complex problems at Fukushima, here's a summary table from the IAEA

Status of the 6 Boiling Water Nuclear Fueled Reactors at Fukushima, Japan as of March 20th 2011 Source​

What's missing are maps with isodose/isoexposure in and around the buildings! It's surpising to have zero data shared! If someone finds the data that I am missing as an isodose/isoexposure map, please post a link!

The Human toll continues. From the BBC News tonight:

Nearly 900,000 households are still without water.

More than 35,000 people are still living in evacuation centres.

"Even if certain things go smoothly, there would be twists and turns," Chief Cabinet Secretary Yukio Edano told reporters.

"At the moment, we are not so optimistic that there will be a breakthrough."

Rescue workers have said the business of collecting bodies has become more disturbing with the passage of time.

Asher

 

[Jerome Marot]

What's missing are maps with isodose/isoexposure in and around the buildings! It's surpising to have zero data shared! If someone finds the data that I am missing as an isodose/isoexposure map, please post a link!

I could not find data for exposure in the immediate vicinity of the building, but you'll find here a simulation of the exposure around Japan (in French):

http://www.irsn.fr/FR/Actualites_pr...simulation_dispersion_panache_radioactif.aspx

 

[Asher Kelman]

I could not find data for exposure in the immediate vicinity of the building, but you'll find here a simulation of the exposure around Japan (in French):

http://www.irsn.fr/FR/Actualites_pr...simulation_dispersion_panache_radioactif.aspx

Thanks, that's helpful. at least someone realizes there should be data disclosed. The French estimate it!!

On the English version of the site:

"To Japanese people and our Japanese colleagues : IRSN collaborators are very concerned with the seriousness of these events and work to help you understand the phenomena. We do hope you and your family are well and that people of Japan keep strength to overcome these difficult times. »
Jacques Repussard, Director General

Our site will provide shortly some information in japanese and in english regarding the situation in Japan."

 

[Asher Kelman]

Public Dosimetry Project underway in Japan: Buy your own dosimeter and post data!

At last, the public will now get the needed data

Source

 

[Asher Kelman]

The power cable to the #2 reactor is not carrying enough power! Also nothing can happen yet as the ventilation to the control room needs to be repaired so that workers can return.

"Hundreds of employees from the Tokyo Electric Power Company, which owns the disabled Fukushima Daiichi Nuclear Power Station, worked through the weekend to connect a mile-long high-voltage transmission line to the No. 2 unit in hopes of restarting a cooling system that would help bring down the temperature in the reactor and spent fuel pool.

After connecting the transmission line on Sunday, engineers found on Monday that they still did not have enough power to fully run the systems that control the temperature and pressure in the building that houses the reactor, officials from the Japanese nuclear safety agency said.

Engineers were also trying to repair the ventilation system in the control room that is used to monitor conditions in the No. 1 and No. 2 units. When that work is completed, the power company can begin cleansing the air in the control room so workers can eventually re-enter and begin using equipment inside to monitor conditions in the two reactor units.

Workers at the plant were also trying to connect a separate power cable to Reactor No. 4." Source​

Looks like another 4 days before anything happens. Maybe pumps have to be replaced and controls have to be rerun.

Asher

 

[Asher Kelman]

Sadly, the radiation in reactor # 3 is proving troubling on several accounts.

First it's difficult to know what's going on. It seems that the radiation containment may be breached.

Yesterday, moving a cable to connect a pump, radioactive water went into several workers' boots and they were hospitalized with burns.

The state is mapping locations of everyone in the 19 mile radius of the reactors to allow location and rapid removal if needed. A lot of folk are still trapped at home with no gas an no services.

Quiet advice is now being used to get people to move out of the 19 mile perimeter.

In order to reconnect the reactor cooling, the air voids and residual contaminated water has to be removed. This is done by getting on a ladder and connecting a hose and draining to drains on the ground. It's that water which went into the workers boots and burnt them.

Sad there's no robotics for this!

Asher

 

[Doug Kerr]

Hi, Asher,

Thanks for the updates and continuing commentary.

Meanwhile, here in North Texas, where even pronouncing Spanish words correctly is considered traitorous ("remember the Alamo", dontcha know), the indigenous TV anchors are still trying to render "Dai-ichi".

The member of the US House for a nearby Gerrydistrict has opined that "we are much safer here since the plant in Japan required manual intervention by the operators whereas here everything is fully automated".

Best regards,

Doug
30.6 miles north of a two-unit Westinghouse BWR plant, 3.3 GWe overall

 

[Asher Kelman]

The member of the US House for a nearby Gerrydistrict has opined that "we are much safer here since the plant in Japan required manual intervention by the operators whereas here everything is fully automated".

Things are happening very slowly. So far the human tragedy of loss by the earthquake overshadows the nuclear accidents. We don't know how many were simply swept to sea in the giant waves or buried among rubble. Yesterday an SUV truck was found floating out 6 miles in the water. It looks as if losses my reach 20-27,000 souls. Still that is not as bad as the 1923 Tokyo temblor which cost 140,00 lives from the quake and 6,00 Koreans dead in lynchings afterwards!

In all this terrible tragedy, we are learning hard lessons on new safety measures required in industrial plants, from engineering design to corporate culture and then to oversight. There's a long way to go, but industrialization itself is not safe.

Asher

 

[Asher Kelman]

"Levels of radioactive iodine in the sea near the tsunami-stricken Fukushima nuclear plant are 1,250 times higher than the safety limit, officials say.

The readings were taken about 300m (984ft) offshore. It is feared the radiation could be seeping into groundwater from one of the reactors. But the radiation will no longer be a risk after eight days, officials say. [Then likely, we are talking about high levels of I-131, an iodine radioactive nuclide with a half life of 8 days.However, if this is a ground water leak, then it may not decrease as it will be continuously fed from the stricken reactor. ADK]

There are areas of radioactive water in four of the reactors at the plant, and two workers are in hospital. [The ones dragging an electric cable through contaminated water that went into the simple ordinary non-safety short boots of the *workers. ADK]

The plant's operator says the core of one of the six reactors may have been damaged. [Reactor #3 ADK]

It has announced that fresh water rather than seawater will now be used to cool the damaged reactors, in the hope that this will be more effective.
Prime Minister Naoto Kan said the situation was "very unpredictable"." Source BBCNews


*Other workers with protective gear did not get the radiation burns from water getting into their boots. The water comes from hose workers on ladders attach to valves to drain air pockets and segments of water from the main cooling system for the reactor vessel. Its not supposed to be radioactive if the valves all worked properly and pipes & pipe joints didn't leak. The released water is let down to the floor where it's supposed to drain and then be filtered to remove radioactivity. However, it seems to have built up, for some unexplained reason. ADK

 

[Asher Kelman]

Many of the workers, arriving in shifts are said to be low paid and not necessarily trained or dressed for the job of handling radioisotopes safely. Doesn't seem fair! Still, all industrialization has a considerable cost in workers lives. In China last year, over 2400 coal miners died. I am not justifying anything, just looking for perspective in the cost of having people live far beyond "hunter gatherer societies" where food and energy nowadays has to be harvested on massive scales. It's likely, that the risk of death per family unit has decreased with industrialization although the horrors are more evident as they occur before our very eyes on TV and pictures.

Again, nature is far more cruel. With 10,000 dead counted and still 17,500 missing from the earthquake and the tsunami that followed, the cost from the nuclear disaster has been minimal. The potential loss of 5 people or less due to the explosions etc in the stricken nuclear plants and future illness in say 150 to 1000 people, at the most, is indeed painful, tragic and wasteful loss. It just seems so much worse and even "evil" because we believe it was so preventable! This has always been man's dilemma. Going under the mammoth to spear it, always had risks! Hopefully we learn to be more prudent when we ask the folk to kill a mammoth from below!

Unfortunately, shipping has been rerouted to avoid Japan. This is increasing the shortages of fuel and raw materials to sustain the Japanese people and help restart the economy. The upsurge of violence in the Middle East has unfortunately diverted attention to the vast number of poor Japanese in the north Eastern coastal areas who are without power, fuel, limited food, no jobs and living as refugees or feeling abandoned and cut of in their shuttered, shattered neighborhoods near the nuclear plants.

U.S. marines based in Japan start to clear rubble in Sendai, Miyagi Prefecture, March 25, 2011 as reconstruction
continues at Sendai airport, which was hit by the earthquake and tsunami in northern Japan. U.S. forces will provide water to
help cool the reactors at Japan's stricken nuclear plant north of Tokyo. Source:Reuters Date:03/25/2011See more images: Here.http://www.ibtimes.com/articles/127...r-massive-earthquake-photos.htm#ixzz1Hk0vU2nohttp://www.ibtimes.com/articles/127...r-massive-earthquake-photos.htm#ixzz1Hk0vU2no​

On the positive aide, the International community is inserting itself into the fact collection and measuring radiation levels from Tokyo towards the plants and air sampling overhead. Well equipped and provisioned rescue parties are still arriving in Tokyo. Already there, Russian, Chines, Korean, Israeli and Mexican teams help survivors and the displaced. The US navy is still providing food water and humanitarian help from carriers off shore, although they are now further away from the coast because of the rising radioactivity. When the aircraft return, everything and everyone gets showered. There's little risk from ill effects after that!

Still our response has been late and tepid at best. Thank goodness the human spirit of the Japanese has not been broken. Only right now, the young, "used to everything material" generation, is learning from postwar elders how to manage with much less right now and then rebuild.

Asher

 

[Asher Kelman]

For the folk bearing the brunt of the hardship and deprivation, there's little solace these days.

For the rest of us, however, even in such horrible disasters, there's good news. Given that the 4 reactors damaged in the 9.0 earthquake were the oldest design, not built for such a real life stress test, (and given the apparent shoddiness and shortcuts admitted to by the plant management), it's quite amazing that the disaster is no greater than the current unthinkable uncontrolled mess contaminating the area. There's no mushroom cloud and no wipe out of life. Also long term health effects are likely to be negligible. This to me is really astonishing! Who could have imagined we could get away with shortcuts and sloppiness and not have a mushroom cloud of isotopes spreading for hundreds of miles! What this means is that with modern plants and updating safety with a much more stringent set of standards we should be able to make nuclear energy safe. Unfortunately it's too late for the homes and jobs of the people in the stricken area. They have become guinea pigs in allowing us to learn not to be so foolhardy and sloppy. I hope that the folk get restitution so they can restart their lives elsewhere.

Unfortunately, reactor 2 is likely lost as it appears that the containment vessel has been burnt through already giving rise to some very localized leakage of uranium and plutonium that can only come from the vessel being breached.

Richard Lahey, who was head of safety research for boiling-water reactors at General Electric when the company installed the units at Fukushima, told the Guardian workers at the site appeared to have "lost the race" to save the reactor, but said there was no danger of a Chernobyl-style catastrophe.

Workers have been pumping water into three reactors at the stricken plant in a desperate bid to keep the fuel rods from melting down, but the fuel is at least partially exposed in all the reactors. At least part of the molten core, which includes melted fuel rods and zirconium alloy cladding, seemed to have sunk through the steel "lower head" of the pressure vessel around reactor two, Lahey said. The indications we have, from the reactor to radiation readings and the materials they are seeing, suggest that the core has melted through the bottom of the pressure vessel in unit two, and at least some of it is down on the floor of the drywell," Lahey said. "I hope I am wrong, but that is certainly what the evidence is pointing towards." Source.​

Even with this disaster, the damage will be limited and will be contained within the next several years.

So where's the good? What will come out of this it seems is a

• Formal international monitoring system
  
  
• Data handling and translation to layman's terms so people can make rational decisions
  
  
• Regional emergency intervention teams
  
  
• Penetration of private companies veil of secrecy when there's an incident

It's not that easy to extract energy on an industrial scale by coal without thousands dying in the mining and 100's of thousands becoming ill indirectly because of pollution. Although clean wind and wave power energy sound great, and indeed they are, the real choice right now is between nuclear energy and coal. It's likely to be far easier to make a major improvement in reactor design than alter the nature of coal and its effect on our health.

Sadly, the Japanese in the disaster area and the poor workmen in the plant are suffering right now. A lot of the area depends on fishing and small vegetable gardens and now all this is threatened with radiation levels being reported all over the place from normal to very high. Without a rational approach to measurement and publication of radiation exposure maps as well as translating that for the public, the Japanese around the danger zone are really like war refugees, even in there own homes!

Asher

 

[Doug Kerr]

AP headline today:

Radiation 10,000 Times The Health Standard at Plant​

Or maybe 100 times - those units are so pesky!

Best regards,

Doug

 

[Jerome Marot]

Or maybe 100 times - those units are so pesky!

Quite possible. I have seen measurements divided by 10 between the morning and the afternoon on the International Atomic Energy Agency web site (I should have made a printout...). If even them can't get it right the first time, who can?

BTW: a radiation level 10000 times health standard at the plant is no surprise. The health standards presume that there are zero leaks. Any leak is a lot bigger than zero.

 

[Asher Kelman]

Quite possible. I have seen measurements divided by 10 between the morning and the afternoon on the International Atomic Energy Agency web site (I should have made a printout...). If even them can't get it right the first time, who can?

BTW: a radiation level 10000 times health standard at the plant is no surprise. The health standards presume that there are zero leaks. Any leak is a lot bigger than zero.

Part of the issue is how one measures. Exposure in air should be taken at a fixed position from some surface and then closer to it. If the radiation is actually coming from radioactivity on, (or below) the surface, then the close reading will be higher. For a point source this will increase by the inverse square law. So going double the distance from the source will bring the dose from the radioactivity down by 1/4. Now if there's radioactivity suspended in the air, then the exposure rate will be the sum of exposure from the point source on the surface and the exposure from the radioactivity in the air.

So one can see how a measurement in an area where surfaces are contaminated and there's Iodine 131 in the air could give widely variant measurements. Now there's another issue. Many radiation meters give the exposure reading in rem and not sieverts. 1 sievert = 100 rem. Given that the workers are over-stressed, underfed, some sleeping on the floor with one blanket, are over-exposed to radiation, poorly equipped, not all have radiation badges to monitor their own exposure, we cannot rely on them for perfect measurement.

There are 4 sources for getting measurement besides Topco:

• The IAEA measurements from Tokyo and towards the Fukeshima
  
• Citizen measurements
  
• French nuclear teams arriving today focussed on the stricken plants
  
• Japanese Government

However, so far, no integrated maps. It also may be that some folk might still be alive but abandoned in the neighborhoods near the plants where investigators wont go.

Asher

 

[Jerome Marot]

I think that you are severely underestimating the capabilities of a country like Japan. I would think that they have modern counters and people capable of using them. OTOH, the person writing the summary on the IAEA site may be a bit confused between mega and kilobecquerels, etc... No big deal, I said that it was corrected during the course of the day. The report was 3 Megabecquerels per square meter about 30km away from the plant. This would have been as bad as Chernobyl. It was corrected to 0.3 megabecquerels (0.34 today), which is still bad, but a lot less.

What I also wanted to say is that reports like "x times the health standard" are meaningless, for the simple reason that the health standards are very, very low. That should not be interpreted as "the health standard are too low, let's get sloppy", but as "radiation 10000 times the health standard at plant is cause for concern, but does not mean that the people working there are dead".

 

[Don Ferguson Jr.]

Yep,that makes it even more pathetic that a rich and highly technical country like Japan cannot provide their workers the right equipment like the safety boots the MSM is talking about.

 

[Asher Kelman]

s.

What I also wanted to say is that reports like "x times the health standard" are meaningless, for the simple reason that the health standards are very, very low. That should not be interpreted as "the health standard are too low, let's get sloppy", but as "radiation 10000 times the health standard at plant is cause for concern, but does not mean that the people working there are dead".

Jerome,

It's a little more complex. It also depends on the quality of the radiation and the time in which a dose s accumulated. So, for example, getting a years dose in 15 minutes does indeed become a problem for workers, especially if they each don't have badges. Where that is happening it's time for robots to do the measuring. But we really have almost zero detailed news from inside the reactors and the workers routines. Without everyone being badged and the reports published, we are all kept in the dark. Perhaps there is careful monitoring but this is not being shared at this time.

Asher

 

[Doug Kerr]

Asher: you know a lot more about this than I do. If I have gotten it wrong, straighten me out.

************

Summary

It is important to recognize that, in these various reports of the radiation situation, we will encounter (at least) two distinct quantities. The have different implications, dimensionality, and units.

• Values denominated in the SI unit becquerel (the non-SI unit is the curie) (or, more likely, becquerels per square meter) tell us the "potency" of the radioactive source. (In the case of undesired radioactivity, we can think of this as an indicator of the level of radioactive contamination.)

• Values denominated in the SI unit sievert (the non-SI unit is the rem) tell us the accumulated expected biological impact (over some period of exposure) on an affected creature.

************

Here is the more detailed story.

It is important here to recognize that, just as we have in photometrics, there are (at least) three different quantities that may be spoken of, with different implications, dimensionality, and units. The three quantities are broadly analogous, in photometrics, to the luminous flux from a source, the photometric exposure on a receiving surface, and the "exposure result" on that surface.

Radioactivity

The radioactivity of a source tells us, in effect, the number of nucleus decays per second (for the entire source being spoken of). The SI unit of radioactivity is the becquerel, which numerically corresponds to a rate of one nucleus decay per second.

The non-SI unit is the curie.

For an extended surface, we may wish to quantify the radioactivity per unit surface area. The unit of this is the becquerel per square meter. I do not know the scientific name for that quantity.

Absorbed dose

At some "receiving object", from the standpoint of physics, we are concerned with the absorbed dose. This is a quantity that accumulates over time. It can be thought of as the amount of energy "deposited" in the receiving object from the ionizing radiation of one or more radioactive source(s). Its SI unit is the gray (the plural of which is gray - I wish they would do that for other SI units).

The non-SI unit is the rad.

If we are interested in the rate of accumulation of the absorbed dose (in effect, the "exposure" of our receiving object), the unit would be the gray per second. We do not often encounter this quantity and unit.

Equivalent absorbed dose

When our concern is the expected biological effect (as is usually the case), then the quantity of interest is the equivalent absorbed dose. Like the absorbed dose, this is a quantity that accumulates over time.The SI unit is the sievert.

The non-SI unit is the rem.

If we are interested in the rate of accumulation of the equivalent absorbed dose (in effect, the biological "impact" on our receiving object), the unit would be the sievert per second.

Thus, in summary:

• Values denominated in becquerels (or, more likely, becquerels per square meter) tell us the "potency" of the radioactive source. (In the case of undesired radioactivity, we can think of this as an indicator of the level of radioactive contamination.)

• Values denominated in sieverts tell us the accumulated physiological impact (over some period of exposure) on an affected creature.

************

Best regards,

Doug