Reactor #1 water temperatures have dropped considerably since Wednesday, with feedwater nozzle temperature of 137 oC and RPV bottom head at 113 oC. Temperatures on reactor's 2 & 3 have also decreased, but only a few degrees Celsius for each. Pressures in all three RPVs have not noticeably changed. The primary containment pressures have also not changed since Wednesday.
The US Nuclear Regulatory Commission reports that Fukushima Daiichi is “static but fragile”. (NHK News) The NRC roughly agrees with TEPCO on the extent of fuel damage within the three afflicted reactors; ~67% for #1, 30% for #2, and 25% for #3.
MEXT reports that all but two of their seawater sampling locations are now below health standards for I-131. Six locations show no detectable I-131, and two locations west and southwest show levels slightly above the 0.04 Becquerels/cc standard. The remaining two show detectable I-131, but below the health standard concentration. TEPCO reported that all near-shore and 15-kilometer sea sampling points are now below 1 Becquerel/cc, however all but two are still above the health standard. The two northern-most sampling locations of TEPCO show no detectable I-131.
TEPCO has estimated that the now-infamous power cabling tunnel leak in early April released 520 tons of contaminated water to the sea. The total activity released is estimated to have been 5x1015 becquerels. (a thousand-million-million)
Japan imposed a no-entry restriction midnight Thursday prohibiting residents from remaining within a 20-kilometer radius of the crippled Fukushima Daiichi nuclear power plant “to enhance control of evacuees amid continued fears of radiation leaks.” (Kyodo News) However, the restrictions to access are not quite as bad as many western Press claims. NISA reports families that need to return to their homes for clothing and other necessities need only get permission from either their city's or town's mayor, or head of village. A total ban on access will be enforced for the 3 km. radius, some other specific locations with high airborne contamination levels, and/or those areas devastated by the tsunami where public health risk is considered to be great. Chief government spokesman Yukio Edano said, "We have been asking residents not to enter the area as there is a huge risk to their safety. Unfortunately, there are still some people in the areas." (NHK News)
IAEA also reports a similar mandatory no-entry zone for an 8 kilometer radius surrounding Fukushima Daini. IAEA quotes Edano as saying, "The size of the evacuation zone around the station would be reduced from 10 km to 8 km," and that "the order to evacuate based on the incident at Fukushima Daini nuclear power station would be lifted from areas farther than 8 km around the station."
Why was there an evacuation zone around the Daini power complex anyway? Their emergency power systems worked as they were supposed to work, and there has not been a loss of cooling to any of the four reactors and spent fuel pools. On one hand, the Japanese government needlessly enforces fear of radiation on Daini, then admonishes the world for using fear of radiation to hurt Japanese trade. (see below)
NHK News reports that Japan has asked the international Organization for Economic Cooperation and Development (OECD) to stop other countries from curbing imports from Japan based on unrealistic and unscientific fears of radiation. Japan believes some countries are using their citizen's fear of radiation as a way to promote “protectionist measures” of their own industries. The government feels it's OK to needlessly keep their own citizens from their homes due to fear of radiation, but it's not OK for the rest of the world to use fear of radiation against Japanese trade.
Of the 103 most recent results for foodstuff contamination, 99 were found to either have no contamination or levels of Iodine and Cesium below health standards, including several from Fukushima Prefecture. Four leafy vegetable samples taken inside Fukushima Prefecture on April 18 were found to be below the I-131 standard, but slightly above the Cs-134/137 standard. Clearly, things are getting relatively safe around Fukushima, so where is Mr. Edano's huge risk?
Notorious international nuclear naysayers and prophets of nuclear energy doom, Greenpeace, announce that their “flagship”, Rainbow Warrior II, is on its way to sample the fish off Fukushima Daiichi. “It is critical that independent testing is undertaken, in order to assess the true extent of the contamination and the possible impacts on public health and the food web,” said Junichi Sato, Greenpeace Japan Executive Director.
The true extent of the contamination...right...the same people who's “true extent” methods supposedly prove that thousands of Europeans die each year from phantom Chernobyl cancers.
Reactor temperatures and pressures in the three Daiichi reactors of immediate concern continue to decrease. #1 feedwater nozzle reads 164 oC, and the bottom of the RPV reads 114 oC. The feedwater nozzle on Unit #2 reads 133 oC. Unit #3 nozzle reads 98 oC and the RPV bottom reads 109 oC. Pressures have not changes noticeably since Monday.
The removal of waste waters in the vertical shaft (drainage tunnel access) of Unit #2 has finally begun. These waters are being pumped to storage tanks in the on-site waste treatment facility. It is estimated that there are 25,000 tons of water in the basement and tunnel of Unit #2. The pumping schedule is to move ~500 tons per day. Unit #2 is being drained first in order to keep further tunnel leakage from getting to the sea.
The French nuclear company, Areva, has been contracted to build a water treatment facility at Fukushima Daiichi in order to decontaminate the waste waters. Their process reduces contamination levels by at least a factor of 100, and as much as a factor of 1000. On-site storage of the waters will continue until the new treatment facility is completed. The facility is designed to decontaminate 1200 tons of water each day.
TEPCO today announced they have sampled the water in Unit #2 spent fuel pool (SPF) and found Iodine and Cesium concentrations higher than in #4 SPF. This is an indication of some fuel damage, but whether it is more or less than unit 4's SPF cannot be determined.
Residual waste waters in the basement of Unit #6 turbine room have been “transferred” into #6 condenser.
The high voltage switchgear for units 1&2 and 3&4 (it seems they are paired) has been re-connected. What this will mean to the recovery of normal cooling systems remains to be seen.
TEPCO has added six new seawater sampling points, two at 8 km. and four at 3 km. distances from the shoreline. All other 10 TEPCO and 10 MEXT sampling points will continue to be used, as well. Three of the new sites south of the power complex show Iodine-131 concentrations slightly above health standard, consistent with the original ten TEPCO locations measured April 17. Three of the new northern sites, as well as the two most northern of the ten original sampling locations, have Iodine-131 activity levels below health standards. All other TEPCO and MEXT locations have not noticeably changed in their concentrations of I-131 over the past 5 days. IAEA says the overall trend is for decreasing activity levels.
As of April 18, 8 “containers” of rubble and debris had been collected and removed from the vicinity of Reactor Buildings 1–4. The containers are being stored elsewhere on the TEPCO property.
TEPCO began spraying all rubble with a “polymer hardening agent” to keep loose surface contamination on the rubble from becoming airborne.
The Japanese Nuclear and Industrial Safety Agency has suggested, after looking at more than 5 weeks of data, it is possible that fuel pellet melting has occurred in all three stricken reactors, not just #2. The degree of meltage for each reactor cannot be deduced, at this point.
A team of IAEA BWR experts have toured the Fukushima Daiichi and Daini facilities and “noted a strong, positive attitude broadly displayed by the management, support and task implementation teams, even though the situation is not yet stabilized. Activities appeared to be well organized, efforts were thoroughly planned, and responsibilities well communicated.”
Asahi Shimbun has polled nearly 2000 of their readers, and 51% believe the Japanese nuclear electricity program should remain as it is, 30% say the reliance on nuclear should be reduced, 11% say that all nuclear plants should be shut down, and 5% say more nuclear plants ought to be built. 56% of the readers are “greatly worried” about Fukushima, and 33% “worried to some extent”. 73% of the readers felt the government's involvement in Fukushima information flow has been “inappropriate”. 62% of Asahi's readers disapprove of Prime Minister Kan's actions with both Fukushima and the tsunami recovery efforts.
Hiroshima Syndrome updates...
Prime Minister Kan today proposed to stop all existing nuclear plant construction plans until a new, more thorough examination of nuclear safety has occurred, a-la America's Rep. Markey some weeks ago. The Japanese government approved building 14 new nukes last June. Kan made the proposal to the government's Upper House Budget Committee. Asahi Shimbun says the details of Kan's proposal are “unclear”. Kan also wishes to permanently forbid anyone returning to their homes within 20 km. of Daiichi. “Many staff members” of the Prime Minister's office say Kan “gave his remarks without thoroughly weighing the issues”. Clearly, Kan is promoting a political state of nuclear panic.
The Japanese government reports that some of the residents and their families evacuated from the 30 km. radius around Fukushima Daiichi are being discriminated against, similar to what happened to the survivors of Hiroshima. The government has broadcast that “radiation is not infectious”. While relatively few people treating evacuees disrespectfully, the number of incidents has been enough for the government to say something. The government says most of the Japanese public seems calm and supportive, but there is a small fraction of citizens who are “over-reacting”.
Temperatures and pressures in reactor pressure vessels 1, 2 & 3 continue to decrease. The feedwater nozzle temperatures are 179 degrees C for #1, 141 C for 32, and 92 C for #3. Pressures for # 2 & 3 indicate atmospheric, while #1 pressure is down to ~60 psi.
Containment pressures for #2 and #3 remain at atmospheric while #1 is above atmospheric (~24 psi abs.) due to the nitrogen injection.
Western news reports on Saturday that the sea contamination at Fukushima has sharply increased seem to be, once again, misleading. The increases detected have been from samples taken inside the containment fences and silt dams put in place last week to minimize releases to the open sea. (KYODO News) The factor of six increase indicates that the fences and dams are restricting the outflow of radioactive isotopes to the open sea, and as such the levels inside the dams are going up. This was hoped to be the case when TEPCO installed the barriers, and it seems to be working.
All Japanese news media today report that robots have been used inside reactor buildings 1 & 3 in order to inspect damage and measure radiation exposure levels. The highest reading so far are inside the access doors of Unit #3 on the first floor (ground level?) and vary between 28 and 57 millisieverts per hour (2.8-5.7 REM/hr.) These are very high, but not really unexpected for the severity of the situation. A worker in these fields would reach the emergency dose limit of 25 REM (250 millisievert) in 4-7 hours. Reactor building No. 1 levels were from 10 to 49 millisieverts/hr (1-4.9 REM/hr). In both cases, the amount of recovery work any individual could perform would be severely limited. Remote control robots will be used to do as much as possible, but sending workers into these areas do do some work is inevitable. The robots can do only so much. There is no word on plans to reduce dose levels, at this point. Measures to reduce dose levels and increase worker stay times will unquestionably happen, but how these things will occur needs considerable planning time.
All Japanese media also report that new, externally-located pumps and “coolers” will be installed to speed up the process of dropping reactor temperatures below the 95 degree C cold shutdown level. The coolers are actually portable heat exchangers that will use sea water to cool the waters circulated to and from the reactor pressure vessels. Kyodo News reports TEPCO has ordered “dozens” of “gasketed plate heat exchangers” for the job. They measure 3 meters high, on meter wide, and two meters long. TEPCO plans using “five or six” heat exchangers for each reactor's cooling.
TEPCO told the Press that merely pumping water into the fuel pools and reactors is not cooling them down quickly enough. The fuel pool levels drop due to evaporation caused by decay heat production, and the waters pumped and/ or sprayed into them recover the levels. The reactors, however, are a different story. TEPCO reports indicate that the waters being pumped into the reactors is ending up as raised water levels in the turbine buildings. This writer has mentioned several times that the flow paths have not been reported, and it would be helpful to everyone if this was done.
TEPCO reports it could take at least 3 months to stop all leaks from the stricken reactor plants, and up to 9 months to bring all three reactors into a cold shutdown condition. Details are necessarily sketchy. However, JAIF summarizes as follows...
1. Cool reactors 1 and 3 by circulating water through them, through coolers, and then purify the water for re-use. It sounds like a closed loop, of some sort
2. TEPCO will have to stop the continued leakage from the #2 reactor system by “patching the damaged section” before applying the cooling process planned for the other 2 units.
3. Because Unit #2 will take the longest to bring to a cold shutdown condition, its time-line will be essentially the “critical path” toward completion. The “critical path” is that part of a process that will take the longest time to accomplish.
4. Water purification systems will be used to remove radioactive materials from all waste waters so they can be re-used in the cool-down process.
5. TEPCO plans to put giant covers over the reactor buildings and use the tested resin sprays to prevent additional airborne releases.
6. TEPCO will increase the monitoring and sampling points in the surrounding evacuation areas during the first 3-6 months, and the results will determine decontamination measures needed to allow people to return home.
TEPCO also reports water level in the underground tunnel from Unit #2 continues to increase, but the concentration of radioactive contamination in the water seems to be decreasing. This seems to be a combination of the relatively rapid decay of iodine 131, and the reduction of radioactive materials leaking out of the plant system. In fact, all tunnel activity levels at Fukushima seem to be dropping.
The seawater contamination levels off shore also seem to be dropping, with the exception of the one location 30 km due west of the power plant complex. The sea sampling points 15 km off-shore have not seemed to change since last week.
TEPCO has announced that recovery of some of their “thermal” power plants, damaged by the quake/tsunami, has allowed them to no longer have rolling blackouts. The reserve power margin is small, so occasional losses of power to some locations might occur.
Conditions in and around the Fukushima Daiichi power complex continue to improve. Reactor water temperatures slowly decrease for Units 2 & 3, and there seems to have been a major drop in #1 reactor water temperature since yesterday of more than 20 degrees C. (Now 197 C – JAIF). Pressure in Unit #1 reactor pressure vessel has dropped accordingly, and is now ~63 psi. The other two reactor vessel pressures continue to be at atmospheric. All three primary containment pressures continue to be stabilized. Work at the plant continues in order to drain the turbine building basements and staunch the flow of radioactive isotopes to the sea.
There are no new seawater contamination levels to report from either TEPCO or MEXT due to their three times per week schedule. There should be some new information by Sunday.
The United States government has lifted the evacuation advisory for families of American government employees in Japan. The US State Department says the situation in Japan is “dramatically different” from when the advisory was issued. The department continues that reactor cooling and other mitigation efforts have been successful, thus radiation risks and contamination are low and “do not pose a significant risk”. However, the USA continues to advise that travel within the 80 km. radius of Fukushima Daiichi is to be avoided.
If it wasn't for the Hiroshima Syndrome affliction, the evacuation advisory and the overly-restrictive avoidance distance for travel would never have happened.
Kyodo News and NHK Japan report that Japan's Atomic Energy Society (AES) now believes that fuel damage in Units 1 and 3 reactor fuel cells progressed to melting of the uranium fuel during the first several days of the emergency. They caution that the meltage was not the catastrophic type that would burn through the 7 inches thick cast steel of the bottom of the reactor pressure vessel, but rather produced the formation of granular material 1 millimeter to several millimeters in size. These have fallen to the bottom of the reactor vessel and are now dispersed evenly.
One problem immediately arises. The re-iteration of the catastrophic meltdown myth popularized two weeks ago by so-called experts in the western news media, is given tacit verification. They should look at the data from Three Mile Island, a severe meltdown, and speculate based on what was found there, but not lionize China Syndrome fictions. Japan's AES seems to have a bit of the Hiroshima Syndrome affecting them, where exaggerated myth seems reasonable because all things nuclear are always presented in exaggerated form. Nuclear fuel wouldn't “just melt”...something more horrible must be possible. In addition, AES says the melting is in reactors 1 & 3, but there is no mention of unit #2. On the other hand, TEPCO and NISA have reported their greatest concern for fuel damage is #2 reactor core. There's an apparent contradiction here between these two groups of Japanese experts, and it ought to be resolved ASAP. There should be a united informational effort between all portions of the Japanese nuclear community, otherwise it appears they are confused. Finally, later in the report (Kyodo News) AES contradicts themselves by saying the fuel bundles in reactors 1 & 2 were the ones uncovered by water, and that the fuel in reactor #3 was always submerged! How can a submerged nuclear fuel cell experience melted fuel?
Kyodo News reports the reactor pressure is dropping (as reported above from JAIF data), but they then say it's, “...an indication that air inside the reactor has leaked outside, but that no major changes in radiation levels have been detected.” In other words, Kyodo News implies there's something wrong with TEPCO's credibility. How could there be a leak from the intensely radioactive reactor and no increase in radiation levels outside the reactor? TEPCO must expeditiously correct obvious news media errors like this, because all news sources have the penchant to make “two plus two equals five” statements. Fix this fast.
Kyodo News also reports that Japan is sending their State Foreign Secretary to the Ukraine on April 26, for the 25th anniversary of Chernobyl commemoration. The Secretary is supposed to allay fears concerning Fukushima. WHAT??!! Never send a politician to do an engineer's job! At least accompany him with experts from JAES, JAIF, and/or NISA who know what they are talking about.
On one final note, it is reported by TEPCO that four of their “thermal” power plants at Hirono, Hitachinaka, and Kashima were knocked off line by the March 11 earthquake/tsunami, but they have not been restarted. Hirono Units 2 & 4 were reported to be “devastated” by Denki Shimbun on March 29. Hitachinaka Unit #1 (a 1000 MWe supercritical coal plant) is to be restarted by the end of July. Kashima Unit #6 (1000 MWe oil-fired) is expected to be restarted in a few days. So, why hasn't the press covered these stories?
From on-going Japanese Press reports, it seems TEPCO and NISA believe Unit #2 reactor fuel cell has the most damage, compared to reactors 1 & 3. In fact, they think much of Unit #2's fuel cell has melted. As a result, this writer has been puzzled for more than two weeks. More fuel damage usually means more hydrogen. So, why was there no hydrogen explosion in the upper spent fuel handling area of Unit #2? Just wondering...
Speaking of spent fuel (weak segue), The Japanese news media reports TEPCO has remotely sampled the water in unit #4 spent fuel pool and found I-131 and Cs-137 levels indicative of some fuel damage. In fact, TEPCO says that most of the fuel bundles appear undamaged. NISA says the isotopic levels are about 100,000 times higher than would be typical for pool water with no damaged fuel, but much lower than expected in a worst case scenario. The levels reported indicate that relatively few fuel bundles are actually damaged. Western Press generally speaks of over-heating as the cause. While over-heating is one possibility, there are also two others which are at least as likely, as reported in Japan. First, a considerable volume of debris and structural steel fell into and on top of the pool. Plus, the large, multi-ton polar crane used to move fuel bundles in the pool, collapsed on top of it all. This could have caused physical damage to at least some of the fuel bundles sufficient to release the I-131 and Cs-137 in the sample. Further, the heavy debris lying on top of the fuel bundles may have restricted water flow through some of the fuel clusters resulting in localized pockets of over-heating. Second, several rain showers and storms have probably washed the isotopes coating the debris over the pool, into the pool. However, no-where in the Japanese Press do we find speculation that the water level in the pool ever dropped low enough to expose the fuel clusters. NISA says this possibility cannot be totally eliminated, but the debris-damage scenarios are now possible since remote cameras have shown the considerable amount of debris coverage over the entire spent fuel handling deck. In this writer's opinion, the debris did the damage...not overheating.
Asahi Shimbun reports that TEPCO and NISA are putting together plans for the removal of all spent fuel bundles in #4 spent fuel pool. The recent remote camera images and the relatively low isotopic activity level of the water in the pool make them feel removal of the fuel bundles is possible. Their preliminary idea is to fabricate a metal structure around the pool area. While radiation levels right now would make this impossible, by raising the water level to maximum the radiation levels would drop considerably. Camera images indicate there was at least 2 meters of water above the fuel bundles when the sample was taken, then 195 tons of water was injected into the pool, raising the level another meter. Radiation level was detected at 84 millisievert/hr. By adding four more meters of water level ( ~740 tons) and filling the pool, radiation levels will plummet. One foot of water lowers radiation levels by a factor of ten. Four meters of added water shielding will drop rad levels by a factor of more than a trillion. (ten to the twelfth power) Once the fuel pool cooling and cleaning system is functional, much of the isotopic concentration in the water can be filtered out which will further lower the rad level. Cleaner water and higher water levels ought to provide a relatively safe condition for the construction of the metal enclosure.
The actual removal and storage of the fuel bundles is preliminarily planned to utilize the process and equipment developed for the removal of the severely melted fuel cell at TMI. Because it is not thought there is widespread meltage of the fuel cells in the #4 pool (if any), removal of the cells and their examination for possible damage level will be much, much easier than the TMI experience. The fuel clusters can then be loaded into 100 ton casks (under water, of course), and the casks then removed by cranes for storage at a yet-to-be-determined location at Fukushima Daiichi. In addition, the equipment used at TMI was remote-operated in order to keep radiation exposure to the operators as low as reasonably achievable. (ALARA) However, what will actually be done at Fukushima depends on how low radiation levels become after the pool is filled, the water fully filtered and cleaned, and all the contaminated debris has been removed from the upper deck.
One thought-provoking aside...wouldn't it be interesting if one of the most important outcomes of the TMI meltdown turns out to be the procedures and equipment used for the safe and successful clean-up of Fukushima?
It now seems (Asahi, again) there are three emergency power lines that have been strung into Fukushima Daiichi. All three come from a Tohoku Power Company transmission station about a km. inland. Two of the lines are connected to Units 3 through 6, and the other to Units 1 & 2. Monday's earthquake temporarily interrupted power through the line to Units 1 & 2 (50 minutes), but did not interrupt the flow of electricity through the other two lines. One encouraging implication is that the Japanese companies have put their competitive differences aside for the good of everyone. (Standing-O)
In addition, the emergency mobile generators and many of the fire trucks used to pump water into the reactors before the emergency power lines were completed, are still on-site. They were available if the loss of power to Units 1 & 2 became extended.
The milk from the farms surrounding 7 cities and towns in Fukushima Prefecture is now available in local stores. Tests on the milk by three separate labs all agreed that the milk was safe for unrestricted consumption. This indicates, not only are the conditions at the Fukushima power complex calming down, but the world around the power complex is beginning to recover, as well.
NHK Japan reports TEPCO's April 12 seawater samples show that activity levels of the water next to Unit #2 have dropped by a factor of 1000 since April 2. (from 7.5 million Bq/cc down to 2,500 Bq/cc) This was not in the levels supplied by the JAIF report yesterday.
Kyodo News reports that the April 7 earthquake aftershock exceeded the design basis for the Onagawa Nuclear Power Station. The Onagawa design basis is 451 gal (a vertical acceleration unit), while actual vertical acceleration was 471 gal. The was no damage to any of the Onagawa equipment, and there should not have been. Be reminded, the design basis is the minimum specification required to be met or exceeded in order to be licensed to build the plant. What the actual as-built specifications might be are never given political or legal credit. As it turns out, the GE design used for reactor and containment construction in Japan has a generic design criteria (as built) approaching 1000 gal. Isn't it about time that governments give political and legal credit to as-built specifications for nuclear plant safety, and not the preliminary specifications used to decide the make and model of plant to be built?
TEPCO is now using double-layered “silt dams” in the further attempt to restrict contaminated leakage from Units 3 & 4 to the open sea. Silt dams are reasonably good at collecting suspended solids from water flowing through them, but the dissolved stuff passes right on through. Iodine is mostly in a suspended form, but a small fraction is necessarily dissolved. Thus, the silt dams should restrict most of the I-131 leaking, but not all of it.
TEPCO measurements of the radiation level at the property boundary is now below the 5 microsievert/hr limit.
TEPCO reports that water level in a trench outside Unit#2 was lowered 6 cm by pumping the water into Unit #2 condenser. Several hours later, the water level had re-risen 4.5 cm. It seems the trench will not be drained until the waters inside the turbine basements are removed. The water in the #2 turbine basement began to be pumped into the condenser using a submersible pump on April 12.
Finally, TEPCO says they will begin inspection of the Kariwa nuclear power station on April 15. After inspection, they will decide if any “restoration” work needs to be done before restarting the power plants. The restarting of the seven units at Kariwa would increase Japan's electrical capacity by nearly 8,000 Megawatts. The delay in doing this was in order to provide all available resources to the Fukushima Daiichi emergency. Now that things have become relatively stable, efforts to restrat Kariwa's power plants can begin.
So, what's more important? Recovery from a disaster that kills more 25,000 and makes hundreds of thousands homeless, or mitigation of a grossly exaggerated nuclear emergency's risk because of fears predicated on misunderstanding and misconception? The Hiroshima Syndrome strikes again.
For nearly a week, the situation at the Fukushima Daiichi power complex has been slowly stabilizing. The three sets of reactor pressure vessel temperatures have been decreasing and their internal pressures have been stable and steady, with unit 2 & 3 approaching the 95 C temperature which IAEA defines as cold shutdown. Plant operators now seem to be using spent fuel cooling system piping to feed freshwater into the pools, rather than use of the water spraying. Spent fuel pools are being kept full in all reactor buildings and their temperatures have stayed below the 50 C level, except for Unit #4 which has risen sharply and water spraying has increased to counter it. While none of the processes used to maintain water levels and temperatures can be called routine, these make-shift methods have stopped the further degradation of plant conditions which marked the first 20 days at Fukushima. Until the slow process of draining the waters from each of the turbine building basements is completed, the equipment installed to provide emergency cooling water to the reactors and spent fuel pools cannot be operated. Once these systems are operating, all three reactors and all four spent fuel pools can be brought into cold shutdown.
The same can be said for radiological conditions on land and at sea. Things are no longer deteriorating. To the contrary, airborne activity levels and sea water contamination concentrations have been steadily dropping for several days. In fact, seven of the ten 30 km. off-shore sampling points are below the 0.04 Bq/cc I-131 standard. Only the three sampling points due west of the power complex remain slightly above the health standard for I-131. Near shore contamination levels are currently at their lowest since March 15, with the concentrations at Daiichi being lower than those at Daini, 10 km. south. This does not mean Daini power complex has any seawater leaks. The shore currents tend to flow south in western Japan, so the numbers indicate that the leakage rate of I-131 to the sea at Daiichi is dropping. Part of this drop comes from Daiichi plant staff stopping leakage from the now-infamous power cabling pit crack, their on-going efforts to limit mixing of the port/dock waters inside their break-wall with the open sea, and the drop in I-131 levels due to it's 8 day half life.
Let's look at the I-131 numbers. We can logically assume fuel damage in units 1, 2 & 3 reactor fuel cores did not get worse after March 18, the date when the fire trucks and their pumps arrived at the scene to boost replenishment water flows through the steam-driven pumps that were intermittently feeding the reactors. This has allowed the reactor operators to cover the fuel cells with at least 10 feet of water, stopping further decay heat damage. Thus, we have had a bit over 3 half-lives for the bulk of the I-131 released from the fuel prior to March 18 to decay, reducing the specific activity by a factor of 8.
On the good news front, the Kariwa nuclear power station, 150 km. west of Fukushima, has done an airborne activity analysis for Cesium, and the levels are between a million and two million times lower than the health standard. The resulting annual whole body exposures are 3 million times lower than the 1 millisievert number the Japanese like to call normal.
One interesting note to this writer, the background radiation levels of April 11, in the 25 cities monitored by MEXT and IAEA, have shown no appreciable decreases, while the radiation levels at the perimeter of the Fukushima Daiichi property are dropping. If this trend continues, could we be seeing the first-ever natural background radiation monitoring for these 25 cities? Up to this point, background radiation data around the world has focused on three population groups. The first is in the vicinity of all nuclear power stations, each of which is located away from urban areas. The second are those areas with high backgrounds, like the Kerala Plateau in India and the beaches of Brazil. The third comprises housing developments atop known Radon gas emitting rock formations. Except for these few areas of radiological interest, background radiation levels in cities and rural areas around the world are largely unknown. Hopefully the process of world-wide urban (as well as rural) natural background monitoring begins with Fukushima. Then we can let mother nature be our guide in setting safety and health standards that are realistic.
No matter, things only seem to be getting better at Fukushima Daiichi. The problem is time and patience. The rate of stabilization is slow, but steady. There will be no rapid improvements for several days, at least, until the turbine basements are drained. The 700 operating staff and emergency workers at Fukushima Daiichi will tirelessly continue to do their jobs. For the rest of us, it appears we have reached a point where we can hunker down and practice our faculties of patience. On the other hand, the news media will not hunker down and wait. This goes for both the Japanese and the rest of the world. Now, they shift into what I call the “interim mode”, between the event-filled period of the emergency escalating and diminishing, and the eventual period of “coverage” I've previously called The War Against the Atom where the prophets of nuclear doom take stage. During this interim period, the Press is resorting to “human interest” and “flashback” stories.
On the human interest front, we have an article from Asahi Shimbun (Tokyo's largest newspaper) concerning the so-called “Fukushima 50”, popularized by western news media. The first paragraph takes a subtle stab at western Press by pointing out that there have been some 700 workers toiling at Fukushima from early-on in the emergency. Not 50. Later in the article, the western Press is further subtly chided by pointing out that the number of workers at the power complex never went below 70, at then only once when dark smoke began billowing out of the rubble heap atop Unit #3's reactor building. That seems to have been the only true “evacuation” of the site by non-essential personnel. The other “evacuations” were actually when workers outside the damaged buildings were told to move away to a safer distance for a while, only as a precaution to prevent unexpected increases in whole body exposure. They're not getting huge pay raises to coerce people to work there either. Check it out... http://www.asahi.com/english/TKY201104110137.html
On the “flashback” angle, we have another Asahi Shimbun article entitled, “WHAT WENT WRONG: Fukushima flashback a month after crisis started”. One interesting note concerning on of my pet peeves; emergency actions should be the sole domain of the plant's highly trained operators, and what they do should not be interfered with by politicians. Let the experts on site make the decisions and keep the politicians as far away as possible because they can do nothing but make matters worse. I learned this with TMI when all the data from plant instruments strongly indicated that a severe level of fuel melting had probably occurred, but president Carter literally ordered the NRC to call the accident a “near meltdown” which left the door open for wild “what if” scenarios to proliferate for years.
It seems powerful political interference was the case early-on in the Fukushima emergency. Early in the morning of March 12, Prime Minister Naoto Kan became frustrated with the information he was getting from TEPCO, so he helicoptered to the emergency facility 5 km. from the scene of the emergency and put himself in charge. He wanted the venting of pressure from reactor no. 1 to begin immediately, and this was not happening. Of course, with a complete loss of power, the venting could not happen, but Kan didn't understand because he has little or no knowledge of nuclear plants. Regardless, he arrived at the emergency center and demanded the venting start immediately. It took some time to explain to him that this was not immediately possible, and what would have to happen before a manual venting process could happen. He wanted it to happen ASAP, regardless. Kan left an hour before the venting began. Five hours later, the hydrogen that accumulated in the upper refueling deck area because of the venting, exploded. This may have happened anyway, but Kan's nuclear-ignorant orders certainly did nothing to improve the situation, and may well have accelerated the time-table for the first hydrogen explosion. But, Kan's exacerbating interference did not stop there. Back in Tokyo, after finding out that fuel damage of a severe nature had occurred in one or more of the reactor fuel cells, Kan and his staff descended on TEPCO head quarters and put themselves in charge of information flow. One Ministry official reported they were placed in the unwieldy position of "not releasing any information before it was first submitted to the Prime Minister's Official Residence." WHAT??? This is the blind leading those with vision! Why were TEPCO and other government agencies so slow with their release of information? The guilty finger can only be pointed at Prime Minister Kan. Read about it for yourself... http://www.asahi.com/english/TKY201104120153.html
As I'm sure you all know by now, Japan's Nuclear and Industrial Safety Agency (NISA) has raised the classification of the Fukushima emergency from 5 to 7 on the international scale. (INES) The only nuclear accident previously rated this high was Chernobyl. It has suddenly made Fukushima the number one news story in the world...again. Here's why the classification has been changed...
Re-examination of the numerous radiation monitoring levels and environmental sampling results compiled from the first day of the emergency revealed much higher volumes of two principle isotopes of concern, Iodine-131 and Cesium-137, than had been previously estimated. Both isotopic volumes are now understood to be greater than the “several tens of thousands of becquerels” necessary for the INES level 7 classification.
The majority of the I-131 and Cs-137 volumes occurred during the early days of the emergency, during and following the three hydrogen explosions. Atmospheric isotopic releases increased after the three explosions until water sprays for the spent fuel pools and fire truck pumping to boost water flows to the three reactor vessels were available. Atmospheric releases have decreased steadily and significantly since then. The re-classification does not mean the emergency situation has worsened, in fact radiation levels, contamination concentrations, and reactor 1, 2 & 3 parameters all continue to drop, and are lowest now than they have been since March 11.
While many western news media sources say the contamination of foods, vegetables, drinking water, and the nearby ocean contributed to the new classification, there are no such classification standards in the INES definition of a level 7. Only airborne activity volumes (i.e. total becquerels) and whole body exposures (i.e. millisieverts) are used for the emergency classification.
While Fukushima is now classified at the same severity level with Chernobyl, it does not change the fact that it is not a Chernobyl accident all over again. "Same classification" does not mean "same accident". Here are some of the more important distinctions...
Chernobyl was a single reactor which experienced a titanic fuel cell steam explosion because of ridiculously poor design (some called it a stupid design). Fukushima is a three reactor emergency, and there have been no explosions of any kind in the fuel cells of any of them.
Chernobyl's volume of I-131 and Cs-137 released during their accident was more than 10 times greater than what has come out of Fukushima.
Chernobyl's rate of atmospheric release was essentially constant for 15 days, before the emergency team literally froze the destroyed fuel cell by injecting liquid nitrogen into the catacombs below the reactor compartment. Fukushima's rate of atmospheric releases peaked after the unit 3 hydrogen explosion, and has dropped exponentially over the 30+days since. This is, like with rate of decay heat decreases explained in the first few updates, a reversal of Al Gore's hockey stick graph, only less steep than with decay heat.
Chernobyl was located in the middle of Eastern Europe, surrounded by land and people. No matter which way the winds blew, people were subject to Chernobyl's radioactive releases. Fukushima is on the ocean shore, and for the first several days of the emergency, when the greatest volumes if I-131 and Cs-137 were released, the winds were blowing out to sea, and not over populated land areas.
It was several days into the accident at Chernobyl before members of the public were evacuated. At Fukushima, evacuation of the 3 km. radius began before the first hydrogen explosion, and the extended evacuations out to 20 km. began immediately upon the first explosion. These actions severely reduced the millisievert exposures to the surrounding population, keeping them at least 100 times less than Chernobyl’s surrounding population. It also eliminated the possibility of having Chernobyl's "highly contaminated" members of the public. (more later)
The Soviet government severely censored nearly all of the information they received from the thousands of people trying to stop the release of raw fission products into the atmosphere, and kept it from the billions world-wide. While this writer has taken TEPCO and the Japanese government to task over their informational ineptitude, their level of informational flow has been several orders of magnitude better than what the Soviets did in 1986. The Soviet Union covered up information, but there is no evidence of this happening in Japan.
The Soviets did nearly nothing to prevent the ingestion of contaminated foods during the accident, until the United Nations (through WHO) put extreme pressure on them to get it done. Their efforts to identify I-131 tainted foodstuffs were less than optimum after that. Case in point, 4000 children were discovered to have thyroids literally saturated with I-131 from drinking raw, contaminated milk. Many were found to have cancerous growths already forming on their thyroids. Surgery to remove the growths, and medications to flush the I-131 from the children were unbelievably successful. All were pronounced cured by 1989. It should be noted that the Chernobyl Forum report (more on this later) in 2006 said 9 of those children died of thyroid cancer as adults, but none of the deaths could be confirmed to be Chernobyl-related.
Conversely with Fukushima, the Japanese government and health organizations, as well as the IAEA, were “monitoring, collecting and analyzing” from the first day of the emergency, not only in the Fukushima Prefecture (state) but in all of the contingent Prefectures, too. Contaminated food stuffs found to exceed health standards were confiscated and destroyed. As a result, it is unlikely that many, if any, children with I-131 saturated thyroids will occur.
There are robust, still-intact containments surrounding Unit 1, 2 & 3 reactor pressure vessels at Fukushima, while Chernobyl had no containment structures whatsoever. Plus, each reactor fuel cell at Fukushima is surrounded by a seamless, at least 6.5 inches thick, carbon steel pressure vessel inside the containment, while Chernobyl's fuel cell had no pressure vessel surrounding it, of any kind.
Eventually, all three reactors at Fukushima will be in the cold shutdown condition of optimum safety, while Chernobyl probably still fissions (at a low but detectable level) below it's massive concrete mausoleum.
There are numerous other differences between Fukushima and Chernobyl, but the above are this writer's “big ones”. Regardless, it should be enough to get the point across...same classification does not mean same accident
Finally, we must address the potential health impacts of Fukushima. Because of the world-wide reports connecting the two, we must also return to the health impacts of Chernobyl. All media, both inside and outside Japan, are reporting several real and theoretical death numbers concerning Chernobyl, then pointing out that if Fukushima gets worse it could be as bad. Western Press (BBC, CNN, Fox, and etc.) reports a NISA spokesman said Fukushima could still get worse and eventually release more radiation than Chernobyl. I've checked all the Japanese Press at my fingertips and can't find that one anywhere. Regardless, here's the comparative death tolls and health effects estimates...
The 2006 WHO report on the 20th anniversary of Chernobyl said 50 emergency workers, helicopter pilots, and plant operational staff died as a result of over-exposures to radiation fields in excess of 3 sievert (300 REM). How much many of them actually got can only be estimated, but may have been in the 10 sievert (1000 REM) range. In addition, two plant employees died early-on in the accident from severe injuries due to the explosion inside the reactor chamber. (for a more detailed explanation of how this happened, see “The Chernobyl Disaster” page of this website) There have been no deaths at Fukushima due to the nuclear emergency, although two bodies were found that appeared to have drowned in the tsunami. The three men who were heavily contaminated and received whole body exposures greater than the emergency limits (but nowhere close to approaching the radiation sickness threshold) are alive and healthy.
The 2006 WHO report also states that there have been no long-term health effects, and no increases in hard tumor frequency or cancer incidence in the generally exposed population which surrounded Chernobyl. Since Fukushima has released 10X less radioactive material, and the surrounding populations were evacuated early-on, any report alleging death numbers concerning the Fukushima-area population should be totally ignored. It should be noted, there was one radiation health effects model in 1986 (then-considered “fringe”) that correctly predicted the WHO health effect findings. The radiation hormesis model! In fact, radiation hormesis modeling predicted the population exposed to Chernobyl would experience longer lives, lower cancer incidence, and lower cancer death rates. WHO discovered the lower cancer incidence factor in 2006, and the 2010 European age-adjusted cancer death rate (the whole continent was exposed) dropped for the 9th consecutive year. Coincidence?
All news media reports mention the same WHO 2006 report as saying that 4000 people might die of cancer because of Chernobyl. This is a mild but important confabulation. The WHO report says that, using the Linear, No Threshold (LNT) model for theoretical cancer deaths, as many as 3940 cancer deaths could theoretically occur out of the 600,000 people who worked at Chernobyl to stop the radioactive material releases, and/or took part in the entombment of the destroyed reactor, and/or assisted in the clean-up of the contaminated areas outside the destroyed power plant, or were non-workers evacuated from the highly contaminated areas near the power plant (like Pripyat). These are not considered part of the exposed public identified above. No one has made any estimates of this sort for Fukushima. However, as technically bad as Fukushima's HP has been, it is significantly better than the Soviet Union's Chernobyl HP (if you could call it that).
It should also be noted that a Chernobyl Forum report in 2006 theorized that a worst case number of theoretical cancer deaths in the surrounding population (not the 600,000 Chernobyl workers) could exceed 9,000. The Forum also included the WHO results for Chernobyl workers, but expanded their scope to all evacuees, assuming the average dose to all evacuees was ~30 millisievert, with the highest public exposure to but a few people was ~300 millisievert. The Forum points out that natural background exposures in populated areas of India and China, as well as the famous beaches of Brazil, annually produce exposures above the Chernobyl “average.” Five years of living in these high-background areas provide exposures in excess of the highest Chernobyl public dose (this one's not in the report, but I did a little homework). The Forum notes that these naturally exposed populations exhibit no higher cancer rates than their less exposed peers, and no shorter lifespans. But, they went ahead and did a Liner, No Threshold “death estimate” anyway.
From the questionable to the ridiculous...the notoriously anti-nuclear international “environmental” group, Greenpeace, said in 2006 that 270,000 people in Belarus and the Ukraine willget cancer and 93,000 will die because of Chernobyl. At the same time, nearly 50,000 will die in Russia of Chernobyl cancers. They guaranteed that several thousand people die of Chernobyl-inflicted cancers each year in Belarus, Ukraine, and Russia. Now here's the really creative, terribly gruesome, and totally repugnant part...Greenpeace argues that there is no way of telling a Chernobyl-caused cancer from a non-Chernobyl one. Since there is no safe level of radiation, and further since they say the LNT model grossly underestimates risk (they use the Petkau Effect model), Greenpeace guarantees that people are dying from Chernobyl cancers each day, but their numbers are buried in the millions of annual cancer deaths in Eastern Europe and Russia. You can't statistically find them, but it's radiation so they must be in there right? <wink>
1. Health effects of the Chernobyl accident... an overview; World Health Organization;
http://www.who.int/mediacentre/factsheets/fs303/en/index.html ; 2006
2.Chernobyl's Legacy; Health, Environmental, and Socio-Economic Impacts; The Chernobyl Forum; http://www.criirad.org/actualites/tchernobylfrancbelarus/conclusionsonu_aieasept05/rapsynthetique52p.pdf ; 2006
3. Chernobyl death toll grossly underestimated; Greenpeace; http://www.greenpeace.org/international/en/news/features/chernobyl-deaths-180406/ ; 2006