INSTITUTE FOR POLICY STUDIES

Why Fukushima Is a Greater Disaster than Chernobyl and a Warning Sign for the U.S.

April 20, 2012 · By Robert Alvarez

The radioactive inventory of all the irradiated nuclear fuel stored in spent fuel pools at Fukushima is far greater and even more problematic than the molten cores.

In the aftermath of the world’s worst nuclear power disaster, the news media is just beginning to grasp that the dangers to Japan and the rest of the world posed by the Fukushima-Dai-Ichi site are far from over.   After repeated warnings by former senior Japanese officials, nuclear experts, and now a U.S. Senator, it is sinking in that the irradiated nuclear fuel stored in spent fuel pools amidst the reactor ruins may have far greater potential offsite consequences  than the molten cores.

After visiting the site recently, Senator Ron Wyden (D-OR) wrote to Japan's ambassador to the U.S. stating that, "loss of containment in any of these pools could result in an even greater release than the initial accident."

This is why:

• Each pool contains irradiated fuel from several years of operation, making for an extremely large radioactive inventory without a strong containment structure that encloses the  reactor cores;
• Several  pools are now completely open to the atmosphere because the reactor buildings were  demolished by explosions; they are about 100 feet above ground and could possibly topple or collapse from structural damage coupled with another powerful earthquake; 
• The loss of water exposing the spent fuel will result in overheating can cause melting and ignite its zirconium metal cladding – resulting in a fire that could deposit large amounts of radioactive materials over hundreds of miles.

Irradiated nuclear fuel, also called "spent fuel," is extraordinarily radioactive.  In a matter of seconds, an unprotected human one foot away from a single freshly removed spent fuel assembly would receive a lethal dose of radiation within seconds. As one of the most dangerous materials in the world, spent reactor fuel poses significant long-term risks, requiring isolation in a geological disposal site that can protect the human environment for tens of thousands of years.

Fukushima's devastation two weeks after the tsunami.

It's almost 26 years since the Chernobyl reactor exploded and caught fire releasing enormous amounts of radioactive debris. The Chernobyl accident revealed the folly of not having an extra barrier of thick concrete and steel surrounding the reactor core that is required for modern plants in the U.S., Japan and elsewhere. The Fukushima Dai-Ichi accident revealed the folly of storing huge amounts of highly radioactive spent fuel in vulnerable pools, high above the ground.

What both accidents have in common is widespread environmental contamination from cesium-137.  With a half-life of 30, years, Cs-137 gives off penetrating radiation, as it decays.  Once in the environment, it mimics potassium as it accumulates in biota and the human food chain for many decades.  When it enters the human body, about 75 percent lodges in muscle tissue, with perhaps the most important muscle being the heart.  Studies of chronic exposure  to Cs-137 among  the people living near Chernobyl show an alarming rate of heart problems, particularly among children. 

As more information is made available, we now know that the Fukushima Dai-Ichi site is storing 10,833 spent fuel assemblies (SNF) containing roughly 327 million curies of long-lived radioactivity About 132 million curies is cesium-137 or nearly  85 times the amount estimated to have been released at Chernobyl.

The overall problem we face is that nearly all of the spent fuel at the Dai-Ichi site is in vulnerable pools in a high risk/consequence earthquake zone. The urgency of the situation is underscored by the ongoing seismic activity around NE Japan in which 13 earthquakes of magnitude 4.0 - 5.7 have occurred off the NE coast of Honshu in the last 4 days between 4/14 and 4/17.  This has been the norm since the first quake and tsunami hit the site on March 11^th of last year. Larger quakes are expected closer to the power plant.

Last week, Tokyo Electric Power Company (TEPCO) revealed plans to remove 2,274 spent fuel assemblies from the damaged reactors that will probably take at least a decade to accomplish. The first priority will be removal of the contents in Pool No. 4. This pool is structurally damaged and contains about 10 times more cesium-137 than released at Chernobyl. Removal of SNF from the No. 4 reactor is optimistically expected to begin at the end of 2013. A significant amount of construction to remove, debris and reinforce the structurally-damaged reactor buildings, especially the fuel- handling areas, will be required.

Also, it is not safe to keep 1,882 spent fuel assemblies containing ~57 million curies of long-lived radioactivity, including nearly 15 times more cs-137 than released at Chernobyl  in the elevated pools at reactors 5, 6, and 7, which did not experience melt-downs and explosions.

The main reason why there is so much spent fuel at the Da-Ichi site, is that it was supposed to be sent to the Rokkasho reprocessing plant, which has experienced 18 lengthy delays throughout its construction history.  Plutonium and uranium was to be extracted from the spent fuel there, with the plutonium to be used as fuel at the Monju fast reactor.

After several decades and billions of dollars, the United States effectively abandoned the "closed" nuclear fuel cycle 30 years ago for cost and nuclear non-proliferation reasons. Over the past 60 years, the history of fast reactors using plutonium is littered with failures the most recent being the Monju project in Japan. Monju was cancelled in November of last year, dealing a fatal blow to the dream of a "closed" nuclear fuel cycle in Japan.

The stark reality, if TEPCO's plan is realized, is that nearly all of the spent fuel at the Da-Ichi containing some of the largest concentrations of radioactivity on the planet will remain indefinitely in vulnerable pools. TEPCO wants to store the spent fuel from the damaged reactors in the common pool, and only to resort to dry, cask storage when the common pool's capacity is exceeded. At this time, the common pool is at 80 percent storage capacity and will require removal of  SNF to make room. TEPCO's plan is to minimize dry cask storage as much as possible and to rely indefinitely on vulnerable pool storage.  Senator Wyden finds that TEPCO's plan for remediation carries extraordinary and continuing risk. He sensibly recommends that retrieval of spent fuel in existing on-site spent fuel pools to safer storage in dry casks should be a priority.

Given these circumstances, a key goal for the stabilization of the Fukushima-Daichi site is to place all of its spent reactor fuel into dry, hardened storage casks. This will require about 244 additional casks at a cost of about $1 mllion per cask. To accomplish this goal, an international effort is required – something that Senator Ron Wyden (D-OR) has called for. As we have learned, despite the enormous destruction from the earthquake and tsunami at the Dai-Ich Site, the nine dry casks and their contents were unscathed.  This is an important lesson we should not ignore.

A GEIGER COUNTER BROADCASTS FROM TOKYO

Blogger's Note: I just went on the web for a crash course in Geiger counters and the limiting radiation doses recommended for humans. I found that the average annual dose from all causes received by Americans is 0.36 rem/year and the maximum yearly dose allowed for adults working in radioactive environments is 5.0 rem/year.

Then I found on the internet a real-time Geiger counter running in Tokyo (see below). All day today it has between 16 and 18 counts per minute (CPM). 
This evening the web site showing radioactivity in the U.S. came back on line. At 21:46 MST the CPMs by states were: WA 32,  AZ 19, CO 58 and 24, IN 36, NJ 22, NC 33. According to the site explanation, normal background radiation may average from 10 to 50 and the alert level suggesting an extraneous component is set at 130.  Nevertheless, translation of CPM counts into dose rates as rem per unit time requires knowledge of the type of irradiation, which must be determined by a different method. In the case of 0.66 MeV Cesium-137 gamma rays, the true dose rate affecting the human body involves multiplying the CPM by a factor of 20. So "the jury is still out" regarding whether or not the U.S. CPMs reflect fallout from the damaged Japanese nuclear reactors.

Video clips at Ustream

SENIOR SCHOLAR AND DOE NUCLEAR SAFETY EXPERT ROBERT ALVAREZ EXPLAINS THE TRUE DANGER OF THE CRIPPLED JAPANESE REACTORS: RELEASE OF CESIUM-137 (REALLY NASTY STUFF) FROM SPENT FUEL NOT CONTINUOUSLY COOLED

Bloggers Note: This unfolding tragedy could include radioactive fall out in the U.S.!
The good news is that there is a web site where you can go to find out in real time how severe it may be in your part of the country: http://www.radiationnetwork.com/RadiationNetwork.htm The bad news is that this morning it was shut down...

Meltdowns Grow More Likely at the Fukushima Reactors

March 13, 2011 · By Robert Alvarez
Original here

A hydrogen explosion yesterday at Unit 1 severely damaged the reactor building, blowing apart its roof.

Japan's government and nuclear industry, with assistance from the U.S. military, is in a desperate race to stave off multiple nuclear reactor meltdowns — as well as potential fires in pools of spent fuel.

As of Sunday afternoon, more than 170,000 people have been evacuated near the reactor sites as radioactive releases have increased. The number of military emergency responders has jumped from 51,000 to 100,000. Officials now report a partial meltdown at Fukushima's Unit 1. Japanese media outlets are reporting that there may be a second one underway at Unit 3. People living nearby have been exposed to unknown levels of radiation, with some requiring medical attention.

Meanwhile, Unit 2 of the Tokai nuclear complex, which is near Kyodo and just 75 miles north of Tokyo, is reported to have a coolant pump failure. And Japan's nuclear safety agency has declared a state of emergency at the Onagawa nuclear power plant in northeastern Japan because of high radiation levels. Authorities are saying its three reactors are "under control."

The damage from the massive earthquake and the tsunamis that followed have profoundly damaged the reactor sites' infrastructure, leaving them without power and their electrical and piping systems destroyed. A hydrogen explosion yesterday at Unit 1 severely damaged the reactor building, blowing apart its roof.

The results of desperate efforts to divert seawater into the Unit 1 reactor are uncertain. A Japanese official reported that gauges don't appear to show the water level rising in the reactor vessel.

There remain a number of major uncertainties about the situation's stability and many questions about what might happen next. Along with the struggle to cool the reactors is the potential danger from an inability to cool Fukushima's spent nuclear fuel pools. They contain very large concentrations of radioactivity, can catch fire, and are in much more vulnerable buildings. The ponds, typically rectangular basins about 40 feet deep, are made of reinforced concrete walls four to five feet thick lined with stainless steel.

The boiling-water reactors at Fukushima — 40 years old and designed by General Electric — have spent fuel pools several stories above ground adjacent to the top of the reactor. The hydrogen explosion may have blown off the roof covering the pool, as it's not under containment. The pool requires water circulation to remove decay heat. If this doesn't happen, the water will evaporate and possibly boil off. If a pool wall or support is compromised, then drainage is a concern. Once the water drops to around 5-6 feet above the assemblies, dose rates could be life-threatening near the reactor building. If significant drainage occurs, after several hours the zirconium cladding around the irradiated uranium could ignite.

Then all bets are off.

On average, spent fuel ponds hold five-to-ten times more long-lived radioactivity than a reactor core. Particularly worrisome is the large amount of cesium-137 in fuel ponds, which contain anywhere from 20 to 50 million curies of this dangerous radioactive isotope. With a half-life of 30 years, cesium-137 gives off highly penetrating radiation and is absorbed in the food chain as if it were potassium.

In comparison, the 1986 Chernobyl accident released about 40 percent of the reactor core’s 6 million curies. A 1997 report for the Nuclear Regulatory Commission (NRC) by Brookhaven National Laboratory also found that a severe pool fire could render about 188 square miles uninhabitable, cause as many as 28,000 cancer fatalities, and cost $59 billion in damage. A single spent fuel pond holds more cesium-137 than was deposited by all atmospheric nuclear weapons tests in the Northern Hemisphere combined. Earthquakes and acts of malice are considered to be the primary events that can cause a major loss of pool water.

In 2003, my colleagues and I published a study that indicated if a spent fuel pool were drained in the United States, a major release of cesium-137 from a pool fire could render an area uninhabitable greater than created by the Chernobyl accident. We recommended that spent fuel older than five years, about 75 percent of what's in U.S. spent fuel pools, be placed in dry hardened casks — something Germany did 25 years ago. The NRC challenged our recommendation, which prompted Congress to request a review of this controversy by the National Academy of Sciences. In 2004, the Academy reported that a "partially or completely drained a spent fuel pool could lead to a propagating zirconium cladding fire and release large quantities of radioactive materials to the environment."

Given what's happening at the Fukushima Daiichi nuclear complex, it's time for a serious review of what our nuclear safety authorities consider to be improbable, especially when it comes to reactors operating in earthquake zones.