Fukushima Nuclear Crisis Unwrapped
Some things to ponder as the situation comes under control
As I write this on Sunday afternoon March 20, 2011, it appears the crisis involving six nuclear reactors in Fukushima, Japan, is headed toward cold shutdown. That's good news for the tens of thousands of people who evacuated the area following an order from the Japanese government. It is good news for Tokyo Electric Power Corp (TEPCO), which owns and operates the reactors.
Three of the six 40-year old reactors are basically junk having been cooled during the emergency with seawater. The other three were shut down for maintenance when the earthquake hit. Whether any will be re-started is unknown.
Heroism by plant operators made the difference in this emergency. They stayed at their posts knowing, for some, that their homes were swept away by the tsunami, and for others, that loved ones had died in the disaster.
Half a million people are homeless and tens of thousands are missing and believed dead from the combination of a 9.0 earthquake and 10 meter high wall of water (video) that breached the sea walls at the reactor site and elsewhere up and down the northeastern coast of Japan.
Things we know with relative certainty
The crisis at Fukushima was caused by two geophysical events, a huge earthquake and an equally devastating tsunami. For people who ask how the Japanese could have come to build reactors on earthquake faults zones, the answer is because they know how to do it.
Despite the incredible forces of these two events, the reactor cores and primary containment structures of all six reactors appear to have remained intact.
A schematic image of the reactor building. The hydrogen blast occurred in the top portion of the reactor building for Unit 1. The orange piece of equipment in this section of the building is a fuel-handling machine on rails. The reactor vessel is in the center of the image, and the containment structure can be seen surrounding it. (Image source: ISIS)
It is still unknown whether the suppression chamber, or torus, at one of the reactors is breached, but given the dropping radiation levels, it seems unlikely there is damage to the primary containment structure.
The tsunami, which came in at at least 10 meters, swept over a six meter seawall and flooded the electrical switchgear for all six reactors producing blackout conditions. The waves of water also flooded or swept away the fuel tanks for the emergency diesel generators. Some of the electrical switchgear and breaker rooms can be dried out and hooked into external power once it is brought to the site.
TEPCO used fire trucks from Tokyo with ladders that extend to almost 80 feet to pour water into the spent fuel pool at Fukushima reactor #4. The use of helicopters, which dropped huge amounts of water on the reactors, also suppressed radiation by scrubbing it out of the air.
Status of spent fuel pool at Unit #4
According to a “background” telephone call with a senior U.S. nuclear executive, the spent fuel pool at reactor #4 had "normal water" as of Friday morning March 18 and, as a result, the fuel in it will not melt down releasing massive amounts of radiation into the atmosphere.
The executive said that on March 17, the concrete on one side of the pool fell away. That damage may have come from one of the hydrogen explosions. However, the one-and-half inch steel liner around the pool remains intact which means it is likely the pool is not leaking.
The executive also said there is a possibility that reports of "core damage" are speculative that the fuel assemblies in reactors 1-3 may have deformed from heat, but since no one has actually seen them, their condition remains unknown. The term "core damage" does not mean the reactor pressure vessels have cracks or are a source of radioactivity other than what came out when TEPCO vented them.
The executive declined to speak on the record because of the sensitivity of the matter. He did not specify how he had acquired his information. Given the global nature of the firm's work, it is reasonable to assume the company has people on the ground assisting Japanese authorities. I can confirm the executive has no relationship with General Electric which is the vendor that supplied the boiling water reactor technology to Japan.
What did Jaczko know and when did he know it?
This brings us to the testimony of NRC Chairman Gregory Jaczko on Wednesday March 16 to the House Energy & Commerce Committee. Jaczko told the committee he recommended that Americans in Japan evacuate to a distance of 50 miles from the Fukushima reactors.
Earlier in the week, Japanese officials had ordered an evacuation to a 20 km radius (13 miles) around the reactor. Jacko’s statement essentially quadrupled the size of the danger zone.
He said the basis for the recommendation is that there was "core damage" to three of the reactors. He added that there were additional threats of health effects to plant workers and the general population from dangerous levels of radiation.
"We believe that secondary containment has been destroyed and there is no water in the spent-fuel pool. And we believe that radiation levels are extremely high, which could possibly impact the ability to take corrective measures."
Japanese officials in the government and TEPCO executives immediately disputed Jaczko's remarks and his recommendation for a wider evacuation. Japan's nuclear safety agency and Tokyo Electric Power Co., which operates the complex, denied water was gone from the pool. Utility spokesman Hajime Motojuku told the Associated Press the "condition is stable" at unit 4.
Here are some questions about the NRC which need answers
This brings us to the question of how Jaczko came up with his recommendation and why he decided to make it if he had incomplete information. One theory is that he had access to remote sensing data.
The more important question is who else worked with him to develop the recommendation for the much larger evacuation?
Jaczko told Congress the NRC was staffed round the clock with nuclear experts monitoring the crisis in Japan and that a number of NRC staff were over there on the ground. What information, if any, from the operations center and the people in Japan did Jaczko use to develop his testimony?
Did the NRC chairman consult with the four other NRC commissioners before delivering his congressional testimony? They have a deep body of nuclear energy expertise and could have contributed to his understanding of the rapidly unfolding events in Japan.
Did the NRC chairman consult with his counterparts at the Japanese nuclear safety agency and with TEPCO officials?
Did the NRC chairman understand that by ordering Americans to evacuate to a much greater distance of 50 miles than the one ordered by the provincial government in Japan that he was creating new panic in Japan? Worse, from Japan's point of view, his startling recommendation might be seen as intervention in the domestic affairs of a sovereign nation. Did anyone at the NRC work with the U.S. State Department to address the diplomatic issues?
Did anyone advise the NRC chairman that a recommendation made in haste could create more panic, might damage the credibility of the agency, and its ability to communicate with its counterparts in Japan? What was the downside of waiting to get more definitive information?
Is there a possibility that Jaczko's recommendations were written at the White House based on distrust of the information coming from TEPCO and other Japanese sources?
There may also be another answer, and that is the White House had intelligence the NRC could not obtain on its own. Note that several private organizations, including ISIS, published remote sensing images of the damaged reactors.
Red light theory
Is it possible that infra red sensing provided the U.S. government with definitive intelligence about how much water was in the spent fuel pool at Fukushima #4?
Given the sensitively of satellites and aircraft mounted instruments, it might have been possible to get an approximate, or inferred measurement, of the temperature of the remaining water in the pool, which was open to the outside air.
Once you know the temperature of the water, you can make an assumption about how much there is given what is known about the fuel in the pool. For instance, at one point last week TEPCO released data saying the last known temperature of the pool water was about 180 F. This means that while you could cook a chicken in it, it would not boil off. The boiling point at normal atmospheric temperature at sea level is 212 F.
Infrared remote sensing is asset that both the U.S. and Japan have in earth orbiting satellites. This means that a spent fuel pool, with no water in it, shows up as a very bright white spot on the image and is obvious to a trained photo interpretation analyst. If there was no water in the pool, the temperature of the fuel assemblies would be well above 212 F.
Typically, these satellites orbit at about 200-300 miles above the earth in what is called “low earth orbit,” and typically they are in polar orbits which gives them more coverage of the earth’s surface over time.
A fly over at 35,000 feet by a photo reconnaissance aircraft from the U.S. Navy fleet off the Japanese coast, using visible light spectrum and infra red, would show even more definitive results.
Also, in a nuclear facility, operating under normal conditions, discovery of water leaks where they don’t belong triggers a cascade of communications. The shift supervisor and plant shift supervisor are notified and radcon is dispatched to survey it.
In abnormal conditions, it is impossible to predict what might have happened had any of the skeleton staff remaining at the plant noticed a plume of fog at ground level coming off 180 F water, hotter water, leaking into a 34 F atmosphere. That could have accounted for repeated reports of “smoke” from the reactors which in fact was fog from cold air hitting warm water.
This is why there is some speculation that Jaczko may have acquired his intelligence about the status of the spent fuel pool from U.S. military assets which may have also been supplemented or confirmed by similar Japanese assets acquiring similar data. If that’s the case, it would explain why he said the situation at reactor #4 was dire.
Transparency may have come from many sources
However, if none of these assets were used, we are left with unanswered questions about Jaczko's congressional testimony and its consequences.
Both the New York Times and the Wall Street Journal ran stories last week raising the question of whether TEPCO, which has dissembled in communications in the past about the severity of nuclear accidents, was up to it again.
The International Atomic Energy Agency (IAEA) took action upgrading its assessment of the severity of the accident from a lower rating initially provided by Japanese officials. The IAEA Director also complained to the news media he wasn’t getting enough of the right information from TEPCO and the Japanese government.
The Wall Street Journal went further. In a mind bending report, it lays out the case that TEPCO executives delayed in using sea water to cool the reactors. Was this a fear of being blamed for being wrong? Were they trying to save capital assets with multi-billion dollar price tags for replacement.
There is no definitive answer to these questions at least for now.
What remains to be known is how much distrust and incomplete information played a role in what has turned out to look like a decision that didn't have to be made in time for a congressional hearing. Yes, that's hindsight, but these questions deserve answers and soon.
Photo via NRC.
From 2007-2012 Dan Yurman published a blog on nuclear energy. It covered the nuclear energy industry globally including new reactor investments, economics, politics, and technologies. He was a frequent contributor to the ANS Nuclear Cafe http://ansnuclearcafe.org and to Fuel Cycle Week http://fuelcycleweek.com
Other Posts by Dan Yurman
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