pressurized water reactor (PWR): A nuclear power reactor design that utilizes two separate coolant loops, unlike a boiling water reactor. In the primary loop, water is circulated through the reactor core and heated to a very high temperature by fission, but kept under high pressure to prevent it from boiling. A PWR essentially operates like a pressure cooker, where a lid is tightly placed over a pot of heated water, causing the pressure inside to increase as the temperature increases (because the steam cannot escape) but keeping the water from boiling at the usual 212°F (100°C). The heated water is piped through tubes called steam generators, which transfer heat energy to water in a secondary loop, where it is allowed to boil. The resulting steam is used to drive turbine generators to produce electrical power. About two-thirds of the operating nuclear power plants in the United States are PWRs.
probabilistic risk assessment (PRA): A systematic method for assessing three questions that the NRC uses to define “risk.” These questions consider (1) what can go wrong, (2) how likely it is, and (3) what its consequences might be. The NRC uses PRA to determine a numeric estimate of risk to provide insights into the strengths and weaknesses of the design and operation of a nuclear power plant.
Protective Action Guides (PAGs): Suggested precautions that state and local authorities can take during an emergency to keep people from receiving an amount of radiation judged excessively dangerous to their health. The U.S. Environmental Protection Agency developed the PAG Manual to provide guidance on actions to protect the public, such as having people evacuate an area or stay indoors.
RASCAL (Radiological Assessment System for Consequence Analysis): A computer code used by the U.S. NRC to make dose projections for atmospheric releases out to fifty miles during radiological emergencies.
reactor building: Also called the secondary containment, the structure of a boiling water reactor that completely surrounds the containment building. The reactor building houses the emergency core cooling systems and the spent fuel pool (at most boiling water reactors).
reactor core: The central portion of a nuclear reactor that contains the fuel assemblies, moderator, control rods, and support structures. The reactor core is where fission occurs.
reactor coolant system: The reactor vessel (the metal pot housing the reactor core), the piping and components attached to it, and the water contained inside that function to remove heat produced by the reactor core during normal operation and accidents.
reactor core isolation cooling (RCIC) system: A system designed to supply makeup water to a shutdown reactor to compensate for boil-off caused by decay heat when the normal makeup system has failed or is otherwise unavailable. Like HPCI, RCIC uses steam produced by the reactor core’s decay heat to spin a turbine connected to a pump and can run in a stable fashion as long as DC power is available to open its valves and control its turbine speed.
rem (roentgen equivalent man): A unit primarily used in the United States to measure the dose equivalent (or effective dose), which combines the amount of energy (from any type of ionizing radiation that is deposited in human tissue), along with the medical effects of the given type of radiation. The related international system unit is the sievert (Sv), where one hundred rem is equivalent to one Sv.
relief valve (also safety relief valve): Valves installed on reactor coolant system pipes for protection against damage caused by high internal pressure. The valves have springs that keep them closed normally. If pressure inside the pipe rises too high or the operators apply compressed air pressure, a relief valve will open to reduce pressure by allowing reactor coolant system fluid to flow into the wetwell of a boiling water reactor.
safe shutdown earthquake (SSE): The maximum earthquake potential for which certain structures, systems, and components, important to safety, are designed to sustain and remain functional.
Severe Accident Management Guidelines (SAMGs): A set of voluntary nuclear industry guidelines of the 1990s to be used by plant operators in the event of a beyond design-basis accident in which core damage had already occurred or was imminent.
shutdown: A decrease in the rate of fission (and heat/energy production) to reach a subcritical state in a reactor (usually by the insertion of control rods into the core).
sievert (Sv): An international unit of measurement for radiation dosage (1 Sv = 100 rem). According to the World Health Organization, the average person is exposed to about three millisieverts a year of radiation, from naturally occurring, medical, and other sources. Exposure to about one thousand millisieverts (one sievert) of radiation in a short period of time can cause acute radiation sickness.
State-of-the-Art Reactor Consequence Analyses (SOARCA): A study begun in 2007 by the NRC to develop estimates of off-site radiological health consequences for severe reactor accidents.
source term: The amount and isotopic composition of material released (or postulated to be released) from a facility. Used in modeling releases of radionuclides to the environment, particularly in the context of accidents at nuclear installations or releases from radioactive waste in repositories.
SPEEDI: System for Prediction of Environmental Emergency Dose Information. Japan’s national monitoring network to measure real-time dose assessments during radiological emergencies. Developed by the Japanese after the Three Mile Island accident, it began operations in 1986.
spent fuel pool: A pool of reinforced concrete typically about forty feet deep in which fuel assemblies are stored beneath at least twenty feet of water. The water, which circulates to provide cooling, also acts to shield radiation. These pools can be located above the reactor, as is the case with boiling water reactors, or in an adjacent ground-level area, as is the case with pressurized water reactors.
spent nuclear fuel: Nuclear reactor fuel that has been used to the extent that it can no longer effectively sustain a chain reaction.
station blackout: A complete loss of alternating current electric power to the station.
suppression chamber (and suppression pool): See wetwell.
torus: See wetwell.
turbine building: The building housing the turbine/generator and auxiliary equipment.
vent valves (also containment vent valves): A series of valves that factored significantly in the Fukushima accident. The containment vent valves remain closed during normal operation and during design basis accidents. During beyond design-basis accidents, the containment vent valves may be opened to allow gases to be discharged to control hydrogen buildup, remove heat, or lower pressure.
wetwell: In a boiling water reactor, the wetwell sits below the drywell and is connected to it through a series of pipes. The wetwell is sometimes called a torus, suppression chamber or suppression pool. It contains a large volume of water that acts as an “energy sponge” to absorb energy released from the reactor coolant system during an accident.
KEY INDIVIDUALS
In Japan
Shinzo Abe, prime minister (December 2012–)
Yukiya Amano, director, International Atomic Energy Agency
Yukio Edano, chief cabinet secretary (January 2011–September 2011); minister of economy, trade, and industry (September 2011–December 2012)
Toru Hashimoto, mayor, Osaka
Yotaro Hatamura, chairman, Investigation Committee on the Accident at the Fukushima Nuclear Power Stations of Tokyo Electric Power Company
Naomi Hirose, president, TEPCO (June 2012–)
Goshi Hosono, minister of the environment (September 2011–December 2012)
Katsuhiko Ishibashi, seismologist and nuclear safety proponent
Banri Kaieda, minister of economy, trade, and industry (January 2011–August 2011)
Naoto Kan, prime minister (June 2010–August 2011)
Tsunehisa Katsumata, chairman, TEPCO (June 2008–May 2012)
Toshiso Kosako, radiation safety expert, advisor to Prime Minister Kan
Haruki Madarame, chairman, Nuclear Safety Commission
Kiyoo Mogi, seismologist and nuclear safety proponent
>
Koichiro Nakamura, deputy director general, Nuclear and Industrial Safety Agency
Toshio Nishizawa, president, TEPCO (June 2011–May 2012)
Yoshihiko Noda, prime minister (September 2011–December 2012)
Masataka Shimizu, president, TEPCO (June 2008–June 2011)
Kazuhiko Shimokobe, chairman, TEPCO (April 2012–)
Aileen Mioko Smith, executive director, Green Action
Ichiro Takekuro, TEPCO liaison to Japanese prime minister Kan
Masao Yoshida, site superintendant, Fukushima Daiichi Nuclear Power Plant
Atsufumi Yoshizawa, Fukushima Daiichi employee
In America
Steven Aoki, deputy undersecretary, U.S. Department of Energy
George Apostolakis, commissioner, U.S. Nuclear Regulatory Commission
James K. Asselstine, commissioner, U.S. NRC (1982–1987)
Bill Borchardt, executive director for operations, U.S. NRC
Eliot Brenner, Office of Public Affairs, U.S. NRC
Scott Burnell, Office of Public Affairs, U.S. NRC
Charles Casto, deputy regional administrator, U.S. NRC; headed the NRC’s team in Japan
Bill Dedman, reporter for NBC News and msnbc.com
Kirkland Donald, director, Office of Naval Reactors, U.S. DOE
Daniel Dorman, deputy director, Office of Nuclear Material Safety and Safeguards, U.S. NRC (later a member of the NRC’s Near-Term Task Force)
Jack Grobe, deputy director, Office of Nuclear Reactor Regulation, U.S. NRC (later a member of the NRC’s Near-Term Task Force)
Gregory Jaczko, chairman, U.S. NRC (2009–2012); NRC commissioner (2005–2009)
Annie Kammerer, seismologist and earthquake engineer, U.S. NRC
Allison Macfarlane, chairman, U.S. NRC (2012–)
William D. Magwood, commissioner, U.S. NRC
Dr. Charles “Charlie” Miller, director, Office of Federal and State Materials and Environmental Management Programs, U.S. NRC (later the chair of the NRC’s Near-Term Task Force)
John Monninger, deputy chief of staff for the chairman, U.S. NRC, and member of the NRC’s team in Japan
Michael “Mike” Mullen, chairman, Joint Chiefs of Staff
William C. Ostendorff, commissioner, U.S. NRC
Tony Pietrangelo, chief nuclear officer, Nuclear Energy Institute
John V. Roos, U.S. ambassador to Japan
Brian Sheron, director, Office of Nuclear Regulatory Research, U.S. NRC
Kristine L. Svinicki, commissioner, U.S. NRC
Jim Trapp, branch chief, U.S. NRC, and member of the NRC’s team in Japan
Stephen Trautman, deputy director, Office of Naval Reactors, U.S. DOE
Anthony Ulses, chief, Reactor Systems Branch, U.S. NRC, and member of the NRC’s team in Japan
Martin Virgilio, deputy executive director, Reactor and Preparedness Programs, U.S. NRC
Mike Weber, deputy executive director, U.S. NRC
Jim Wiggins, director, Office of Nuclear Security and Incident Response, U.S. NRC
U.S. BOILING WATER REACTORS WITH “MARK I” AND “MARK II” CONTAINMENTS
REACTORS
CONTAINMENTS
LOCATION
Browns Ferry 1
BWR-MARK I
Alabama
Browns Ferry 2
BWR-MARK I
Alabama
Browns Ferry 3
BWR-MARK I
Alabama
Brunswick 1
BWR-MARK I
North Carolina
Brunswick 2
BWR-MARK I
North Carolina
Cooper
BWR-MARK I
Nebraska
Dresden 2
BWR-MARK I
Illinois
Dresden 3
BWR-MARK I
Illinois
Duane Arnold
BWR-MARK I
Iowa
Fermi 2
BWR-MARK I
Michigan
FitzPatrick
BWR-MARK I
New York
Hatch 1
BWR-MARK I
Georgia
Hatch 2
BWR-MARK I
Georgia
Hope Creek 1
BWR-MARK I
New Jersey
Monticello
BWR-MARK I
Minnesota
Nine Mile Point 1
BWR-MARK I
New York
Oyster Creek
BWR-MARK I
New Jersey
Peach Bottom 2
BWR-MARK I
Pennsylvania
Peach Bottom 3
BWR-MARK I
Pennsylvania
Pilgrim 1
BWR-MARK I
Massachusetts
Quad Cities 1
BWR-MARK I
Illinois
Quad Cities 2
BWR-MARK I
Illinois
Vermont Yankee
BWR-MARK I
Vermont
Columbia Generation Station
BWR-MARK II
Washington
La Salle 1
BWR-MARK II
Illinois
La Salle 2
BWR-MARK II
Illinois
Limerick 1
BWR-MARK II
Pennsylvania
Limerick 2
BWR-MARK II
Pennsylvania
Nine Mile Point 2
BWR-MARK II
New York
Susquehanna 1
BWR-MARK II
Pennsylvania
Susquehanna 2
BWR-MARK II
Pennsylvania
Source: U.S. Nuclear Regulatory Commission.
NOTES AND REFERENCES
The following are key sources and explanatory notes for Fukushima: The Story of a Nuclear Disaster. Full references are available at Fukushimastory.com, including links to documents, reports, illustrations, and other materials that played a role in the preparation of this book.
The sources for this book include contemporaneous news accounts published in the United States, Japan, and elsewhere. Extensive use was made of information gathered by several investigations into the Fukushima Daiichi accident that were conducted by official Japanese panels, international industry associations, scientific groups, and the plant’s owner, the Tokyo Electric Power Company, as well as analyses by nuclear safety organizations, notably the Union of Concerned Scientists.
Playing a major role in this book are transcripts maintained by the Nuclear Regulatory Commission of conversations among NRC experts in the United States and in Japan. These transcripts, plus thousands of pages of NRC documents and e-mails related to the commission’s response during and after the accident, provide an inside view of the challenges and uncertainties facing those charged with protecting public health and safety.
The book also draws on the long legislative and regulatory histories of the Nuclear Regulatory Commission and its predecessor, the Atomic Energy Commission. Public transcripts of meetings, written opinions, congressional hearings, and scientific reports were also incorporated.
1. March 11, 2011: “A Situation That We Had Never Imagined”
News accounts of the accident provided descriptions of the early hours of the accident. The Earthquake Engineering Research Institute’s reports on the Tohoku earthquake (available at www.eeri.org/2011/03/tohoku-japan/) offered valuable information, as did two articles published in the Bulletin of the Atomic Scientists, “Fukushima: The Myth of Safety, the Reality of Geoscience” (September–October 2011) and “Fukushima in Review: A Complex Disaster” (March 8, 2012). Additional material came from the Investigation Committee on the Accident at Fukushima Nuclear Power Stations of Tokyo Electric Power Company (www.cas.go.jp/jp/seisaku/icanps/eng/), hereinafter the “Hatamura report,” and the Institute of Nuclear Power Operations, “Special Report on the Nuclear Accident at
the Fukushima Daiichi Nuclear Power Station,” November 2011 (available at www.nei.org/corporatesite/media/filefolder/11_005_Special_Report_on_Fukushima_Daiichi_MASTER_11_08_11_1.pdf).
1. The Richter scale for earthquake magnitude has been replaced among scientists by the moment magnitude scale, which is now the most commonly cited measure for medium to large earthquakes. Although it is not identical to the Richter scale, the moment magnitude scale provides comparable numbers, and they are the ones used in this book. The moment magnitude scale is a logarithmic scale in which each unit of increase in magnitude represents a thirty-two-fold increase in the total energy released. Scientists also use the Modified Mercalli Intensity Scale, which measures the effects of an earthquake rather than its magnitude. This scale has twelve levels of intensity ranging from imperceptible shaking (I) to catastrophic destruction (XII). The Japan Meteorological Agency (JMA) uses yet another scale ranging from I to VII, the highest category. On March 11, 2011, much of the east coast of Japan received Intensity VII shaking, about the same as Modified Mercalli Intensity X.
2. Each control rod (CR) is equipped with position indicators. When all the control rod indicators reflect the fully inserted position, this alarm saves the operators the trouble of having to check each control rod’s status.
3. Alternating current (AC) electricity powers home appliances plugged into electrical outlets. Direct current (DC) electricity powers portable electronic devices with batteries. Many of the components of emergency systems at nuclear power plants, like motor-driven pumps and valves, need AC electricity to run. DC power from batteries can be used for the instrumentation and control systems that operate systems like the isolation condensers and RCIC.
4. The word tsunami was introduced to English speakers by two journalists working in Japan at the time of the 1896 disaster. Eliza Ruhamah Scidmore, an American, wrote an account of the June 15 earthquake and tsunami for the September 1896 issue of National Geographic magazine: “There were old traditions of such earthquake waves on this coast,” she wrote. Scidmore would go on to become the first female board member of the National Geographic Society and play a role in planting cherry trees along the Potomac River. The second journalist to describe the disaster was Lafcadio Hearn. Writing in the December 1896 Atlantic Monthly, Hearn reported: “From time immemorial the shores of Japan have been swept, at irregular intervals of centuries, by enormous tidal waves. . . . These awful sudden risings of the sea are called by the Japanese tsunami.”
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