Bridges vol. 41, October 2014 / OpEds & Commentaries
By Norman Neureiter
After Fukushima—Dissecting a Nuclear Disaster
Just hearing or seeing the numbers 9/11 in the US instantly conjures up the horrors of the 2001 terrorist attack on the Twin Towers in New York – each person with his or her own terrifying images of the events of that day. In many ways that day changed the US forever, especially America’s feelings about security. Nine-and-a-half years later, to the day, Japan was dealt its pair of unforgettable numbers: 3/11. On that day in 2011, at 2:46 p.m., an offshore earthquake of magnitude 9.0 – the largest instrumentally recorded quake ever to strike Japan – along with the tsunami waves that followed over the next hour, wrought immense destruction, thousands of deaths, and billions of dollars of losses on Japan’s northeast coast. But there was more to come. The tsunami, which reached about 42 feet in height at the Fukushima Daiichi nuclear power plant, triggered a sequence of events at the plant that resulted in meltdown of the nuclear fuel in three of the six reactors on the site, hydrogen explosions in three reactor buildings, and the release of large amounts of radioactive material that contaminated the surrounding area and caused the evacuation of some 150,000 people. Three years after the incident, 80,000 people are still displaced and many may never be able to return to their homes.
Those events also resulted in the shutdown of all of Japan’s 54 nuclear reactors (which then were providing some 30 percent of the country’s electrical power), brought about a restructuring of the Japanese government’s nuclear management, regulatory, and safety structures, and stimulated vigorous debate about the future of nuclear energy in Japan and throughout the world. Germany has already elected to shut down all of its nuclear plants – replacing them with natural gas and coal plants, as well as vigorously promote solar and wind alternatives. Every nuclear country in the world has studied the Fukushima accident and drawn its own conclusions. In the US, nuclear industry organizations have done their studies and reports, and the US Nuclear Regulatory Commission (NRC) moved quickly to set up a task force on Fukushima and has begun to implement changes in its own processes for assuring the safety of US plants.
The US Congress also took an interest in Fukushima and asked the National Academy of Sciences (NAS) to study the causes of the accident and to identify lessons learned that could increase the safety and security of US nuclear plants. Congress appropriated funds for the NRC, which then formally engaged the NAS to carry out the study and prepare a report. That report has now been publicly released (in prepublication form), and briefed to the Congress and federal agencies in the US, as well as to nuclear companies, government officials, and regulatory bodies in Japan. “Prepublication” means that all the substance is there (nearly 400 pages of it); it is available for free download on the National Academies Press web site.
So why am I writing about Fukushima three-and-a-half years after the accident? It's because the NAS asked me to chair the committee that would do the study. As you might guess, my reply was: “Who, me?” I was trained as an organic chemist, but for years now have been more of a science diplomat engaged in science diplomacy initiatives around the world. I have no standing connection or working experience with the nuclear power industry. Dr. Kevin Crowley, who directs the Nuclear and Radiation Studies Board under which this study was conducted, countered by noting that I had lived in Japan for five years, had worked with Japanese scientists in the past at a very senior level, and knew something about Japanese culture and language. And because the committee would have to work with the Japanese in gathering information as well as briefing them on our conclusions at the end, he thought my views and experience with Japan could be very useful. Furthermore, on the technical side, the NAS also appointed a vice chair, Dr. B. John Garrick, a long-time expert on risk analysis, with extensive experience in the nuclear industry. There would also be 19 other experts on the committee plus a technical advisor on nuclear safety culture. And so, with some growing excitement – albeit seasoned with considerable humility – I agreed to become the chair.
It was a rich and unforgettable experience. Remarkably, our quite disparate group of 21 dedicated experts worked more than two years on this report. By the time we neared the end, at least 35 other major studies, books and reports, and hundreds of articles on Fukushima had already been published, so we had a great deal of information to draw on and consider. In all, our committee met a total of 39 times – from major, all-member sessions with invited witnesses, to telephone conference calls on specific subjects with smaller groups of experts on those topics.
For those who may not know much about the US National Academy of Sciences, there are some good reasons why it is recognized as one of the finest scientific advisory bodies in the world. It was chartered by the US Congress in 1863 (the charter was signed by President Abraham Lincoln) to provide scientific advice for the government. Membership is honorary and members are elected based on their scientific achievements. In 1916, in order to increase the number of people who could be called on for advice (not to be limited to the small number of NAS members), the NAS organized a new body known as the National Research Council (NRC). With its numerous boards and standing committees created for many disciplinary areas, and some 1100 staff members, the NRC can call on the entire scientific community to serve on its study committees. Committee members receive no financial compensation for serving – only reimbursement for expenses such as food and travel.
Two other honorary organizations have also been created under the NAS charter: the National Academy of Engineering (NAE) in 1964 and the Institute of Medicine (IOM) in 1970. Collectively the four institutions, referred to as “The National Academies,” produce some 400 reports per year. In the world of scientific advice, Academy reports are considered the “gold standard” for their thoroughness, objectivity, and detailed processes that are rigidly adhered to. Meetings to gather information are open to the public, unless classified or otherwise restricted material is involved. In fact, at our Fukushima meetings, public attendees were invited to speak for up to three minutes at the end of the official sessions to convey their views on the issue of the day. At our first meeting, five such individuals did speak. However, meetings for deliberation, discussion of the issues, or drafting text are restricted to committee members, NRC staff, or special invitees.
Once the committee completes a draft report, it is submitted to critical review by outsiders selected by the Academy for their unique expertise on the relevant subject matter. Reviewer comments are taken very seriously. In fact, the Academy appoints one or two additional experts to oversee the review process; and they must affirm that all comments from reviewers have been appropriately considered and addressed by the committee. It has been said that “it is this rigorous review process that truly makes an Academy report what it is!” We had hundreds of comments on the draft report from a total of 24 reviewers, including two from Japan. During the review process, the committee is not told who the reviewers are, but the final document lists all members’ and reviewers’ names and affiliations. Of course, in the final analysis, the committee members alone are responsible for the content of the final report and each member must sign a statement of his/her approval of the finally agreed-upon text.
At our initial meetings in the US, we heard views from the US nuclear industry, the US Nuclear Regulatory Commission, USG officials, and representatives of TEPCO, (Tokyo Electric Power Company): the owner/operator of the Fukushima No. 1 (Daiichi) plant with its six reactors, and the No. 2 (Daini) plant with four reactors. We then traveled to Japan to gather further information.
In Tokyo we had another extensive briefing from TEPCO and also heard from a second nuclear power company (Tohoku) about the successful shutdown of their Onagawa plant. Despite some damage, one off-site power line and three diesel generators survived the tsunami and were able to provide needed power for cooling the reactors. We also learned about the amazing performance of the crew at TEPCO’s No. 2 plant, where one source of off-site AC power and some cooling systems survived the tsunami and helped cool the reactors while crews rushed to lay nearly nine kilometers of temporary power cables in 36 hours – a seemingly impossible feat, in view of the massive destruction and debris throughout the area.
We then visited the devastated Fukushima Daiichi plant site itself, entering the restricted area of some 20 kilometers around the plant. It was a sobering, unforgettable experience proving again that when technology goes wrong, the consequences can be devastating. We met with the operating staff – the people who had been in the plant throughout the event. They took all of our questions and did their best to answer them.
The earthquake’s shaking lasted almost five minutes. In the control room, operators could not stand without clutching the support bar that extended the length of the very long control panel with its dozens of instruments and switches. Due to the earthquake, the operating reactors all “scrammed”: meaning that the control rods were automatically inserted and the nuclear chain reaction halted. There was damage, but the plant survived the earthquake. The emergency diesel generators started automatically and provided power to the plant, even though all off-site AC power was lost.
About 43 minutes after the earthquake, the 42-foot tsunami hit the plant. While damage varied at each of the six reactors, the diesel generators were flooded and lost at reactors 1-5 (loss of AC power), and units 1 and 2 lost their batteries (meaning no DC power) and the switchgear. In unit 3, the batteries supplying DC power survived the wave, but eventually were depleted. Plunged into darkness as well as uncertainty, with instruments not functioning, no way of knowing the condition of each reactor, and no communication with their homes to know whether or not their families had survived, it was a ghastly, frightening time for these workers. And the hydrogen explosions were still to come.
There were also tales of great heroism and resilience on the part of individual workers who braved increasing radiation as they tried to move about the buildings, pump cooling water into the reactors, determine the condition of the reactors, open and close valves, and restore power by going outside and bringing in car batteries, etc. Several workers said that, at one point or another, they had resigned themselves to dying there. Without their achievements, bad as the accident was, it could have been much worse. In the end, fuel meltdown had occurred in reactors 1-3, there was serious radiation release outside the plant, and some 150,000 people had been evacuated by government order.
A well-functioning nuclear reactor of the Fukushima type looks like such a peaceful thing – just sitting there and boiling water to make steam, which turns a turbine to generate electric power, which is then sent to the grid and out to customers. However, temperature and pressures inside the reactor must be controlled carefully by circulating water as needed. But one needs electric power to pump the water, to read the instruments, to open and close valves, and to have lights to see what is going on. Even if a reactor is shut down, heat must still be continuously removed from the radioactive fuel. Without sufficient circulating water for cooling, the fuel overheats, the zirconium alloy cladding around it reacts with water to generate hydrogen that can accumulate in the containment areas and, in the presence of some oxygen, can quickly become an explosive mixture and easily be detonated.
After talking at length with operations people about their personal experiences, we had a chance to tour the seriously damaged plant. We changed into white protective clothing; the cuffs were taped tightly at wrists and ankles, latex gloves and boots were pulled on, respirators with charcoal filters and helmets were added, a dosimeter was given to each person to measure the radiation exposure during the tour, and we were ready to go. Some places were too radioactive for us to enter, but the damage was apparent throughout. In the lower buildings the tsunami had wreaked havoc – its height apparent from marks on the walls. We also went through a reactor building (which had been successfully shut down) and walked up narrow metal stairs, through crammed passages, and over or under supporting structures and pipes to see firsthand how difficult it was to access such places under accident conditions to manually operate various valves.
Especially interesting was the hydrogen story and the visit to reactor number 4. Apparently hydrogen had seeped through the venting systems connecting reactor buildings 3 and 4. And an explosion occurred in the Number 4 reactor building, which I remembered seeing on television at the time of the accident three years before. From the cameraman's position 10 miles away, it looked like just a puff of smoke, but the damage we saw up close at No. 4 was horrendous. The explosion had blown off the top of the building and part of one side. A cage elevator rigged up on the outside of the building took us to the top floor, where we could see the extent of the destruction at the site. As I cautiously walked over to look down onto the cover of No. 4’s spent fuel pool, someone said: “Don’t stay there too long, it’s really hot” (meaning radioactive). I moved away in a hurry.
I would happily have gone without lunch that day, but lunch we did get – returning to the dressing room, disrobing, eating, and then suiting up again, being taped and masked and continuing our tour. The visit to the site put this great calamity in perspective and made clear to all of us how essential it is to try to anticipate everything that could happen to a nuclear reactor and be as prepared as possible to deal with it. For example, there had been little thought or planning about multiple reactors being in trouble at the same time, so accident procedures and guidelines had been developed mainly for single reactor incidents.
Coincidentally, just a few days ago, three young TEPCO workers who had been through the accident visited Washington. One of them had been in the space between reactor 3 and reactor 4 buildings when number 3 exploded, completely collapsing the upper structure of the building and sending pieces flying into the air. He described how he quickly crawled under a truck as debris rained down, realizing that he had just barely escaped being killed, and admitted that he still has nightmares from the experience. He had also taken quite a large dose of radiation while working in the first days after the accident began. During the earthquake itself, he had been working on the fourth floor of the reactor 4 building and he described how fiercely the building shook and how water from the spent fuel pool sloshed out and onto his clothing.
The result of our two years of effort to complete this report is the collection, organization, and analysis of an enormous amount of information about the accident and about nuclear issues in general. We have presented nine findings regarding lessons learned and have made 10 recommendations for consideration. As a non-nuclear expert, I think one particularly interesting chapter in the report is the final one, which stresses the importance of a dynamic and effective nuclear safety culture. It is worth thinking about as remediation work continues at Fukushima Daiichi – a plant that will never operate again and whose decommissioning and cleanup are expected to last another 30-40 years. At the same time, Japan’s political leadership is seeking both official and popular approval to start turning some of Japan’s idle nuclear plants on again. Even as Prime Minister Abe urges the country to do so, his wife has spoken out publicly against it. But these are topics for another day.
Norman Neureiter has been a senior adviser to the AAAS Center for Science, Technology and Security Policy (CSTSP) and the Center for Science Diplomacy (CSD) since July 2009.