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Update On The Status Of The Fukushima Reactors
Please check yesterdays status post for some basic explanations.
"the war situation has developed not necessarily to Japan's advantage"
Emperor Hirohito in his first ever public address announcing surrender on August 15, 1945
"With the help of those involved I hope things will not get worse"
Emperor Akihito in a rare public address on the nuclear crisis, March 16, 2011
Early Wednesday all workers were removed from the Fukushima Daiichi plant for about an hour because of high radiation level. Some 50 have since returned to continue the operation. 50 people are too few to be able to control six nuclear reactors in dire straits. Satellite pictures from DigitalGlobe show very severe damage to reactor buildings 4, 3 and 1 and a hole in the wall of reactor 2 (thanks to The Paper in comments).
We are near total core meltdown in at least two of the six Daiichi reactors additionally to very severe problems in several of the spent fuel ponds. The only chance left now to avoid more serious radiation release may be the Chernobyl option, i.e. to drop thousands of tons of sand and lead onto the reactors to encapsulate the radiation sources.
The information policy of the operation company Tepco as well as the Japanese government is abysmal.
Unit no.1 is temporarily stabilized. The "feed and bleed" operation continues, i.e. seawater is being added and steam released to further cool down the partially melted fuel rods.
Unit no.2 has a probable breach of the primary containment in the area of the doughnut shaped suppression pool. The spike of radioactivity earlier today was attributed to leakage at unit no. 2. The fuel rods within no.2 are considered to have partially melted.
The primary containment of unit no.3 is now considered to be also damaged. White smoke, likely slightly radioactive steam, is coming out of unit no.3. Pictures shows the top of unit 3 which exploded on Monday with very heavy damage. Access from or to the top to the no.3 building is likely impossible. Helicopters were used to drop water onto the spent fuel pool of unit 3 but the operation was aborted because of high radiation levels. The fuel rods within no.3 are considered to have at least partially melted.
The IAEA reported: “Japanese authorities also today informed the IAEA at 04:50 CET that the spent fuel storage pond at the Unit 4 reactor of the Fukushima Daiichi nuclear power plant is on fire and radioactivity is being released directly into the atmosphere.”
An earlier reported fire in unit 4 has either restarted or maybe was not really put out as had been reported earlier. While the operating company earlier said that it was machinery oil burning, the location of the fire in the north-west corner of the fourth floor of unit no. 4 is consistent with the spent fuel pool burning. A photo at the NYT website shows heavy damage at the outer containment wall of unit no 4. right next to the spent fuel pool. The Digital Globe satellite picture show the no. 4 outer containment with very severe fire damage.
Workers can not get near the pool because of high radiation. A water cannon truck is getting prepared to put water into the pool area through the damaged walls but the access road has first to be cleared of debris to allow the truck to come through. Due to maintenance at the time of the incident the no. 4 core does not contain any fuel rods but the fuel rods in the spent fuel pool are fresh from the reactor and thereby quite hot. Related to unit 4 Kyodo News Agency reports:
The utility firm said Wednesday morning it is considering spraying boric acid by helicopter to prevent the spent nuclear fuel rods from reaching criticality again, restarting a chain reaction.
This is curious as the fuel rods in the spent fuel pools should be in special racks with boric separations. Why does Tepco assume that these are no longer functional?
The reactors of unit 5 and 6 are empty and their fuel is held inside the spent fuel pools there. The temperature in those pools has increased as no cooling circulation can be established.
Radiations level are reported to be "constant at high level" of some 2-3 millisievert per hour.
The Japanese government increased the legally allowable limit of radiation exposure for workers at the plant from 100 to an accumulated 250 millisievert/year.
The wind is currently blowing eastward pushing any radioactive clouds out to the Pacific.
Some pro-nuclear people argue that the reactors withstood the earthquake quite well and only the tsunami created the current problems. I doubt that. The 9.0 strong quake already exceeded the 8.2 design level of the reactors (as the Richter scale is logarithmic, the increase in strength from 8.2 to 9.0 is several fold). The quake certainly already caused some serious damage. The tsunami added to that. What damage was created when will be difficult to find out.
The point is that the design was adopted to a certain level of possible danger but that the real danger turned out to be bigger than the expected one. This is likely to be the case for all existing nuclear plant.
The official death count from the tsunami has now exceeded 11,000 and may still double or triple. Nearly 80,000 housing units have been destroyed. It is unlikely that further survivors will be found in the ruble. Cleanup operations continue.
Additional resources:
AllThingsNuclear
Bulletin of the Atomic Scientists
Digital Globe Sat Pictures
IAEA Newscenter (currently down)
NISA Japanese Nuclear Regulator (last update March 14)
Japan Atomic Industry Forum (regular updates)
Kyodo News Agency
NHK World TV via Ustream
Based upon my significant professional experience studying and working with emergency situations in industrial plants, I would say that the following considerations which I haven’t seen mentioned should be kept in mind:
General
1) There are no applicable, pre-approved emergency procedures for the present situation in Fukushima. Significant aspects of the current situation were unforseen by all involved parties.
2) Accidents generally involve the unforseen interaction of more than one event, error, malfunction, or excursion, as is the case here. Therefore, they are very complex situations to handle, because, before taking action, one must first attempt to be sure that one is correctly identifying all of the relevant events, and their causal or stochastic relationships. Failure to correctly understand the full nature of what is unfolding in real-time may lead to taking the wrong action and significantly worsening the situation.
3) This particular problem is of profound complexity because of its multi-partite, dependent nature. What might be best for, say, an individual problem like an isolated fire, may aggravate a proximate issue, like the cooling of a set of fuel rods.
4) In other words, the very real threat is of some sort of catastrophic domino scenario, as in the progressive explosion of an ammunitions magazine.
5) The situation is clearly already catastrophic and has the potential to become uniquely far more catastrophic.
6) Therefore, normal lines of authority have broken down. What would regularly be handled by plant personnel – an accident – now has local, national and international governments and agencies in a power struggle behind the scenes. Some of those parties may well be trying to influence things, while others may be attempting to avoid personal responsibility and shunt it onto other parties. Various parties involved probably do not trust the knowledge, judgement, and even intentions of other parties. (Why would a plant manager trust a politician to understand events on the ground any more than a field general would trust a politician?) This makes for a very toxic, protracted and disfunctional decision-making process. As they say, too many cooks spoil the miso soup. Japan’s cultural traditions heighten this phenomenon: Whoever gets blamed in retrospect will likely be destroyed.
7) Ideally, there must be consensus discussions, and a designated leader to resolve deadlocks and take ultimate responsibility .
8) In an ideal world, all parties would have a unified sense of what would be best. In the real world, all parties represent real and conflicting interests. For example, it would be naive to not presupose that the town to the north of the plant has its citizens’ interests foremost at heart, while the town to the south has its citizens’ interests at heart. Similarly, the IAEA has the continued viability of nuclear power as a concern, and the US must be concerned about fallout on Alaska and the West Coast, as well as serving as a representative for Westinghouse, who helped put the current administration in power and, through its ownership of the media, controls a significant amount of public opinion.
9) In large-scale industrial accidents there must always be a fall guy. In standard situations, among the parties potentially implicated, and therefore involved in arriving at an ultimate conclusion are the plant designers, contractors, equipment manufacturers, maintainence services, plant management, plant operators, legal representation, various insurance representatives, and various levels of government and regulatory agencies. As in the cases of Chernobyl or 9-11, settling upon the fall guy is generally not so much an exercize in fact-finding and truth telling, as in legal prowess and political expediency.
Specific
1) Most critically, indications are that plant water services are out. This might involve ruptured lines, damaged pumping or cooling equipment, damaged control systems, damaged power systems or any combination thereof. Some of this may potentially be repairable, and some might not. It could take considerable time to diagnose this problem, place it within the larger context of events, and arrive at a plan of action. For instance, if power was out, that could be restored only to find problems maintaining pressure.
2) Indications are that other plant services are out: electricity, air, steam, etc. There may be antiquated air activated control systems not functioning because of this. Electricity, of course, is essential for powering pumps and cooling systems. Back-up systems are infrequently used, and hence, very often fail when brought on line.
3) Indications are that critical process monitoring and control services are not functioning at all, or perhaps only intermitently or inaccurately. This could lead to the hesistancy that we apparently have seen. Without properly functioning pressure, flow, level and temperature indicators and controls, one could accidentally cause more damage in attempting to remediate a situation. For instance, in attempting to cool a reactor core, one could overpressurize the system and blow a line, or more likely, an unreachable relief valve, as happened at Three Mile Island. It is very possible that indicator gauge problems have played a part in the leaking and damaged reactor cores.
4) Valves are designed to either fail open or shut, based upon forseen disaster scenarios at the time of design. It is possible that there were design errors and, because of the radiation, operators are unable to get in and reverse the conditions. There are high point vents and low point drains, as well as level glass indicators that could be damaged and leaking.
5) In the short-term, it might seem that the best situation would be for the wind, and radiation, to blow out to sea. However, that would blow the radiation directly onto the workers attempting to deliver sea water to the damaged areas. If they are unable to continue cooling the overheating fuel, that could lead to a worse situation long-term.
6) There may be an emergency attempt to route sea water around the complex and deliver it from the rear of the complex.
7) We do not appear to be seeing a desired cooling trend at present, but rather, at best a holding pattern, a “whack-a-mole” pattern, or,as seems most likely, a clear and steady deterioration.
8) We might be seeing a holding pattern while either painful political decisions are made, and/or encasement or other materials are brought on scene. The best case scenario would be that they are working to restore some of the aforementioned outed services, and that when they are brought back on line, the system is brought under control.
9) The entire process is likely to take a considerable amount of time to play out.
Posted by: Marshall | Mar 16 2011 22:55 utc | 26
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