Fukushima and the Future of U.S. Nuclear Energy

Lauren Boldon

2011 WISE Intern

Rensselaer Polytechnic Institute

August 5, 2011

Sponsored By:

American Nuclear Society

Executive Summary

The events at the Fukushima Daiichi plant have demonstrated the necessity for new and

amended regulatory standards and legislation that will reinforce those already in place and

continue to protect the public from radioactive releases. There are four areas, in particular, that

require immediate attention. These include offsite emergency preparedness, extended station

blackout Severe Accident Management Guidelines, seismic and flood hazards, the storage of

spent fuel, and continued funding for research and development and university programs.

An assessment of the coordination between local, state, and federal agencies during a

severe event at a nuclear plant would enhance the safety features already in place as well as ease

the public. As the knowledge of nuclear plant operations advances, so should the offsite

emergency preparedness measures. Although there has never been an extended station blackout

(loss of both onsite and offsite power) in the United States, Fukushima demonstrated that one

could occur. Currently, Severe Accident Management Guidelines (SAMGs) are voluntary

applications. However, being voluntary, they are not inspected regularly by the Nuclear

Regulatory Commission (NRC), and as such, there is no guarantee that the SAMGs will aid in an

emergency situation. The NRC must add extended station blackout SAMGs to regulation and

continually assess each plant’s ability to fulfill these requirements during significant events.

Furthermore, rulemaking regarding the reevaluation of seismic and flood hazards every

10 years would allow nuclear plants to better prepare themselves for a severe event. This

rulemaking would include the accessibility of fire mitigating equipment for use in seismic-

induced fires. The last concern is the storage of spent nuclear fuel. Although unlikely, a spent

fuel pool, which houses the spent nuclear fuel, could result in radioactive releases that rival those

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from a reactor. As such, legislation providing a federal directive on the use of dry cask storage

would allow plants to remove much of the older fuel from the spent fuel pools.

Despite the events at Fukushima, it remains clear that nuclear energy has a bright future

in the United States; however it still requires continued support from the federal government in

research and development and university programs in order to reach its true potential. Federal

agencies provide this support through research and development grants, scholarships,

fellowships, faculty development grants, curriculum development grants, and infrastructure

grants. In order to supply highly educated engineers to all areas of nuclear engineering, it is

important to support this critical student pipeline. These programs help develop a strong nuclear

program, so the United States continues to be a leader in nuclear energy as it progresses towards

energy independence and security.

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Forward

About the Author

Lauren Boldon, an undergraduate student in Rensselaer Polytechnic Institute’s Co-terminal B.S.

and M.Eng. Nuclear Engineering Program, is presently researching dynamic light and small

angle x-ray scattering to characterize nano-particles and polymers and determine structural

differences between synthesized and actual samples from Oak Ridge National Laboratory. She is

President of Colleges Against Cancer, councilmember of the School of Engineering Student

Advisory Council, a Renssealer STAR and Women in Engineering Mentor, a committee member

of the American Nuclear Society, and a member of the Nuclear Advocacy Network, Association

of Women in Science, Society of Women Engineers, and National Society of Professional

Engineers. She was a Delegate to the 2011 Washington Nuclear Education Student Delegation

(NESD) and attended the Global Women in Nuclear and Young Leaders’ conferences. Her most

notable achievements include receiving the Nobel Scholar Award, National Society of

Professional Engineers Steinman “Ethics in Engineering” Fellowship, and being named a

National Academy Scholar by Nuclear Education Institute.

About the WISE Program

The WISE Program, or Washington Internships for Students of Engineering, is a 9-week

internship program in Washington D.C., where engineering students are introduced to public

policy. The students, sponsored by their respective professional engineering societies, select an

engineering and technology issue to research throughout the summer and ultimately develop

public policy recommendations to help resolve this issue. The final public policy paper is

published in the Journal of Engineering and Public Policy at the end of the internship program.

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Table of Contents Executive Summary ...................................................................................................................... ii Forward......................................................................................................................................... iv Table of Contents………............................................................................................................... v List of Figures……........................................................................................................................ v List of Tables………………………………………………………………………………………v Abbreviations……………………………………………………………………………………...v Introduction, Issue Definition........................................................................................................ 1 Background, Key Conflicts and Concerns .................................................................................... 5 Policy Alternatives ........................................................................................................................ 25 Recommendations ......................................................................................................................... 30 Works Cited .................................................................................................................................. 34 List of Figures Figure 1: Map of United States Nuclear Energy Plants Figure 2: Emergency Preparedness Figure 3: Diablo Canyon Dry Cask Storage Figure 4: Typical Spent Fuel Pool Figure 5: Number of spent Fuel Rods in Typical U.S Plants and Daiichi Units 1-4 Figure 6: High Density spent Fuel Pools at U.S. Nuclear Reactor Sites Figure 7: Jobs Created for Operating Energy Plants Figure 8: Locations of Nuclear Plants and Significant Earthquakes Since 1973 List of Tables Table 1: Condition of Fukushima Daiichi Units 1-6 Prior to Earthquake and Tsunami Abbreviations AC—Alternating Current ACRS—Advisory Committee on Reactor Safeguards DC—Direct Current EDMG—Extensive Damage Mitigating Guidelines EPA—Environmental Protection Agency EPRI—Electric Power Research Institute ERO—Emergency Reactor Operator FEMA—Federal Emergency Management Agency IAEA—International Atomic Energy Agency INES—International Nuclear and Radiological Scale INPO—Institute of Nuclear Power Operations NEI—Nuclear Energy Institute NRC—Nuclear Regulatory Commission PRA—Probabilistic Risk Assessment SAMG—Severe Accident Management Guidelines TEPCO—Tokyo Electric Power Company

Introduction, Issue Definition

Since the dawn of the nuclear energy industry, the safety of the public continues to be an

issue of paramount importance. Events such as Chernobyl and Three Mile Island have shaped the

nuclear industry and help define many of the accepted nuclear standards and regulations. Just as

new and important safety standards were developed as a result of these two events, new

regulations and rulemaking will undoubtedly be developed in the wake of the events that

transpired at the Tokyo Electric Power Company’s (TEPCO) Fukushima Daiichi nuclear

generating plant, which has 6 reactors and 7 spent fuel pools.

On March 11, 2011, a magnitude 9.1 earthquake struck near the Fukushima Daiichi plant,

resulting in a loss of offsite power. As a result, the diesel generators began supplying backup

power, and the reactors began cooling down. Approximately an hour later, a 14-15 meter

tsunami struck the Daiichi plant, damaging the diesel fuel storage systems, the diesel generators,

and the switchgear. The switchgear ties the electricity supply from the diesel generators to the

plant’s electrical system. All alternating current (AC) power from the offsite electrical grid and

from the diesel generators was lost. Eventually the DC batteries’ electrical supply ran out, along

with the ability to continue cooling the reactor. Eventually, the water within the reactors began to

evaporate, and the fuel in three of the reactors was partially melted. Additionally, a reaction

between the material surrounding the fuel and water resulted in a buildup of hydrogen gas. Once

enough hydrogen gas leaked out and accumulated in the reactor buildings, two hydrogen

explosions occurred, severely damaging parts of the buildings. This was followed by a third

explosion which is believed to have been caused by pressure buildup from steam.

Approximately 100 days prior to the earthquake and subsequent tsunami, one of the

reactors had been shut down, and all of its spent fuel had been transferred to the spent fuel pool.

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Cooling capability was lost for this spent fuel pool, as well as for three other spent fuel pools

along with the onsite power supply. This spent fuel pool was of greatest concern, because it had

more spent fuel present with the highest heat load. Several of TEPCO’s initial attempts to pump

additional water into this spent fuel pool failed. Eventually, a concrete truck and large boom

were used to cool the pool several hours after the tsunami hit the plant. No damage occurred to

the remaining two units because the switchgears and diesel generators were not significantly

damaged and power was quickly restored. Table 1 shows the conditions of all six of the

Fukushima units prior to the earthquake and subsequent tsunami.

Table 1: Condition of Fukushima Daiichi Units 1-6 prior to the Earthquake

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It is necessary to note that the events at Fukushima were beyond the design basis of the

plant. The design basis of a nuclear plant includes the set of conditions that the plant is designed

to withstand without significant damage to the reactor core, such as high mile-per-hour winds

(tornados or hurricanes), high impact (from certain types of missiles or debris), flooding,

earthquakes, and many other types of natural disasters. As part of plant licensing, it must be

demonstrated that the safety related equipment is sufficient to respond and cope with any design

basis event. Plants are also designed to withstand beyond-design basis events, but they may also

use non-safety related systems to aid in this response. During a beyond-design basis event, there

must simply be methods to continue to cool the reactor, as was done at Fukushima. The

Fukushima plant’s design bases for earthquakes and tsunamis were both exceeded. The tsunami

design basis was for a 5.7 meter tsunami, whereas the actual tsunami was 14-15 meters. At this

point in time, it is believed the tsunami caused the majority of problems at the plant and the

damage to pivotal electrical systems.

The International Nuclear and Radiological Event Scale ultimately increased the rating of

the Fukushima Daiichi event to a Level 7 Major Accident, the highest possible rating on the

scale. The rating is based on the impact of the radiation release and its widespread effects on the

environment and to the health of the public. This is precisely why it is important to use the

lessons learned from this event to improve the safety of plants in the United States. Moving

forward, there are three tasks at hand for the progression of the nuclear industry. The first is

assessing the status of current methods of dealing with both design basis and beyond design basis

events, which is already underway. The second step is recognizing additional vulnerabilities that

United States’ plants may possess. In light of the events at Fukushima, certain systems may no

longer be deemed adequate. In addition, it may be necessary to address potential emergency

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scenarios, combining different types of natural disasters or expanding on the beyond design basis

operating procedures. This could require additional analysis for multiple-unit plants. The third

and final task at hand is for Congress and the Nuclear Regulatory Commission to determine the

need for additional legislation or regulation regarding these aforementioned vulnerabilities.

Background, Key Conflicts and Concerns

Nuclear Energy in the United States

Nuclear energy has played a significant role in the United States’ energy supply since the

1950s, when the first commercial nuclear reactor began operating. Presently, there are 65 nuclear

energy plants with a total of 104 commercial nuclear reactors, as the figure below shows.

Nuclear energy accounts for approximately 20% or 800 billion kWh of electricity per year in the

United States. Additionally, there is a large push for energy production in the United States with

minimal carbon emissions. Nuclear energy does not emit carbon dioxide during operations, and

as such, is seen as a key emissions reduction method. Nuclear energy is considered to be a clean

air method of energy production, and makes up 75% of the United States clean energy portfolio.

Furthermore, the amount of fuel required is minimal in comparison to other fossil fuels. “A

single uranium fuel pellet the size of a fingertip contains as much energy as 17,000 cubic feet of

natural gas, 1,780 pounds of coal, or 149 gallons of oil.” (Nuclear Energy Institute)

Figure 1: Map of United States Nuclear Energy Plants

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The public perception of the nuclear industry has also progressed over the years. Bisconti

Research Inc. and Quest Global Research Group performed a survey regarding the use of nuclear

energy on June 17, 2011 (approximately three months after Fukushima). The survey

demonstrated that “Eight of ten residents near U.S. nuclear energy plants favor use of nuclear

energy” and “83 percent give them a high safety rating.” A survey of the general public was also

included. The results showed that 62% of the United States public would accept new reactors at

the nearest nuclear plant; 67% favored the use of nuclear energy; 71% wanted to keep the option

to build nuclear energy plants; and 60% favor building nuclear plants in the future. (Nuclear

Energy Institute16) It is clear that the public recognizes the need for nuclear power in the future.

The structure of the nuclear industry in the United States is unique, as the nuclear plants

are owned, for the most part, by the private sector and regulated by the Nuclear Regulatory

Commission. This is different from France, for example, whose nuclear plants are government

owned. The Atomic Energy Act of 1954 provided that the NRC demonstrates “reasonable

assurance of adequate protection of public health and safety and common defense and security.”

The definition of “adequate” protection has evolved over time through rulemaking and

regulations. Additionally, after Three Mile Island, the industry took it upon itself to establish the

Institute of Nuclear Power Operations (INPO). INPO provides interaction and communication

between the different nuclear plants, promoting them to work with each other and share the

knowledge each of them has learned. With such a large nuclear fleet, the sharing of smaller-scale

events and lessons learned is paramount in preventing larger-scale events. This communication

also applies to accident situations. Any plant in the United States can easily obtain support and

guidance from other plants. It is this dual structure with both the NRC and INPO that makes the

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United States nuclear industry unique. It is for all of these reasons that nuclear energy will

continue to have a strong presence in the United States.

Nuclear Industry Reactions to Fukushima

Progress in the nuclear industry means consistently reassessing safety standards, and, in

the wake of Fukushima, the lessons learned must be applied to the nuclear industry. This process

is being done at the industry level as well as at the legislative and regulatory levels. Industry

level efforts are aimed at improving safety and emergency preparedness. Nuclear plants are

looking at their own training and equipment, as well as emergency preparedness. Based on what

is learned, new processes will be implemented to enhance procedures already in place. The

Electric Power Research Institute (EPRI), the Institute of Nuclear Power Operations (INPO), and

the Nuclear Energy Institute (NEI) issued a report on the measures being taken by the nuclear

industry in light of Fukushima. “The U.S. nuclear industry has established…strategic goals to

maintain, and where necessary, provide added defense in depth for critical safety functions, such

as reactor core cooling, spent fuel storage pool cooling and containment integrity…To achieve

our strategic goals, the industry has established principles to guide the development of its

response actions.” These include:

1. “Ensure equipment and guidance, enhanced as appropriate, result in

improvements in response effectiveness.

2. Address guidance, equipment and training to ensure long-term viability of safety

improvements.

3. Develop response strategies that are performance-based , risk-informed and

account for unique site characteristics.

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4. Maintain a strong interface with federal regulators to ensure regulatory actions are

consistent with safety significance and that compliance can be achieved in an

efficient manner.

5. Coordinate with federal, state and local government and their emergency response

organizations on industry actions to improve overall emergency response

effectiveness.

6. Communicate aggressively the forthright approach the U.S. industry is taking to

implement the lessons from the Fukushima Daiichi accident.” (Report by EPRI,

NEI, and INPO4)

Nuclear Regulatory Commission Reactions to Fukushima

The Nuclear Regulatory Commission established a Near Term task force almost

immediately after the events at Fukushima to conduct a review of NRC processes and to make

recommendations for any potential changes to United States’ nuclear plants in a 90-day period.

The Task Force “addressed protecting against accidents resulting from natural phenomena,

mitigating the consequences of such accidents, and ensuring emergency preparedness.” There

were ultimately twelve key recommendations from this Near Term review:

1. “The Task Force recommends establishing a logical, systematic, and coherent

regulatory framework for adequate protection that appropriately balances

defense-in-depth and risk considerations.

2. The Task Force recommends that the NRC require licensees to reevaluate and

upgrade as necessary the design-basis seismic and flooding protection of

structure, systems, and components for each operating reactor.

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3. The Task Force recommends, as part of the longer term review, that the NRC

evaluate potential enhancements to the capability to prevent or mitigate

seismically induced fires and floods.

4. The Task Force recommends that the NRC strengthen station blackout mitigation

capability at all operating and new reactors for design-basis and beyond-design-

basis external events.

5. The Task Force recommends requiring reliable hardened vent designs in boiling

water reactor facilities with Mark I and Mark II containments.

6. The Task Force recommends, as part of the longer term review, that the NRC

identify insights about hydrogen control and mitigation inside containment or in

other buildings as additional information is revealed through further study of the

Fukushima Dai-ichi accident.

7. The Task Force recommends enhancing spent fuel pool makeup capability and

instrumentation for the spent fuel pool.

8. The Task Force recommends strengthening and integrating onsite emergency

response capabilities such as emergency operating procedures, severe accident

management guidelines, and extensive damage mitigation guidelines.

9. The Task Force recommends that the NRC require that facility emergency plans

address prolonged station blackout and multiunit events.

10. The Task Force recommends, as part of the longer term review that the NRC

pursue additional emergency preparedness topics related to multiunit events and

prolonged station blackout.

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11. The Task Force recommends, as part of the longer term review, that the NRC

should pursue emergency preparedness topics related to decisionmaking,

radiation monitoring, and public education.

12. The Task Force recommends that the NRC strengthen regulatory oversight of

licensee safety performance (i.e., the Reactor Oversight Process) by focusing

more attention on defense-in-depth requirements consistent with the

recommended defense-in-depth framework.” (Nuclear Regulatory Commission

Near Term Task Force 17)

In addition to the Near Term Task force, the NRC issued Temporary Instruction 183. The

results demonstrated that there is inconsistent implementation of Severe Accident Management

Guidelines (SAMG), equipment reliability and accessibility, and training of personnel. As a last

resort during a severe emergency, nuclear plants will refer to SAMGs; these are guidelines for

plant responses to beyond design basis situations and are meant to prevent further degradation of

the reactor core, to maintain the integrity of containment, and to reduce the amount and severity

of any radioactive releases. SAMGs were an industry initiative in the 1990s. As such, they are

still voluntary and site specific. Although each plant has SAMGs, the extent to which they are

exercised and updated vary drastically. Furthermore, the NRC does not directly ensure that

equipment referenced in SAMGs are capable of being used for their specific function, as there is

no regulation making inspections of such equipment an NRC mandate. Equipment necessary for

emergency situations may be unavailable, because it is either no longer functional or it is

otherwise engaged. Furthermore, due to situations such as flooding or seismic activity,

equipment stored in non-seismically secure or non-flood proof facilities may be inaccessible.

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Additionally, if the equipment has not been continually tested and assessed, there is no guarantee

it will work when it is needed, rendering the SAMGs irrelevant in the emergency situation.

Additionally, the ability to physically get onsite plays a significant role in mitigating an

event. Once all onsite methods of restoring cooling capability to the reactor core or to the spent

fuel pool have been exhausted, the next step is to attempt retrieval of offsite coolant. This

however, may prove difficult. Natural disasters could ravage the land, preventing any vehicle

from transporting water to the site. Large vehicles could also be stopped by fallen trees or other

debris. If that were the case, then helicopters or cargo planes would have to attempt to drop water

into the building structures, which may prove ineffective. Furthermore, all of these options take

time and may result in increased radiation release into the environment. SAMGs, after all other

methods have failed, may prove useful in obtaining the necessary offsite water.

Emergency Preparedness

Emergency response includes a combination of planning and support from the nuclear

plants themselves, local, state, and federal agencies, and other private companies that provide

emergency support. Nuclear plants must maintain both onsite and offsite emergency response

plans that are regulated by the Nuclear Regulatory Commission and the Federal Emergency

Management Agency, respectively. These emergency plans are updated as new information on

safety and potential problems arise. The Nuclear Regulatory Commission and the Environmental

Protection Agency issued a detailed report in 1978 on the “planning basis for the development of

state and local government radiological emergency response plans for nuclear power plants.”

(Nuclear Energy Institute18) This included the emergency planning zone, or 10 mile radius,

within which radiation exposure could occur to the public during an accident, as well as the 50

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mile radius in which food products, water, and livestock could be affected from the radiation.

FEMA takes the lead on “policies, procedures, and criteria for…review of state and local

emergency plans and preparedness for managing the offsite effects of emergencies that may

occur at a commercial nuclear energy facility.” (Nuclear Energy Institute18) The figure below

illustrates this emergency response plan. Additionally, the Environmental Protection Agency

developed and issued a manual which aids local and state authorities in making appropriate

decisions regarding radiation protection during an emergency. The offsite emergency response

plan details the processes that involved agencies must follow during a nuclear accident. Through

the exercise of emergency response drills, the coordination between these agencies is practiced

and aids in responding effectively during a nuclear accident.

An additional aspect of emergency preparedness is the transportation of equipment and

personnel on and off site, as well as the distribution of resources and equipment availability and

accessibility. After Fukushima, it is clear that transportation to and from a site may prove

difficult—this ties into the distribution of resources and equipment. Legislation and regulation

must address whether the equipment on site is sufficient and appropriately stored so it may be

accessed in a timely fashion when an emergency strikes. Furthermore, the availability of plant

personnel and equipment to respond to multiple unit events must be included in the emergency

preparedness framework.

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Figure 2: Emergency Preparedness

Extended Station Blackouts

A station blackout is a situation in which all offsite and onsite alternating current (AC)

power has been lost. Current methods of analyzing a station blackout situation, such as the one

that occurred at Fukushima, maintain two assumptions: the first is that AC power can be restored

within 4-8 hours, and the second is that offsite and onsite power losses are separate, independent

events. As such, any prior analyses have not considered events in which both power sources are

lost simultaneously. The tsunami in Japan demonstrated that although this is an unlikely

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occurrence, it can happen. Offsite power refers to the general electrical grid that may become

unavailable, typically due to severe weather or natural disasters. Onsite power refers to the

electricity supplied by emergency diesel generators that power pivotal safety systems.

The Station Blackout Rule, or 10 CFR 50.63, established the criteria on the blackout

duration that specific plants must withstand. These factors included the redundancy and

reliability of onsite emergency AC power sources, as well as the expected frequency and time to

restore offsite power. In addition to the Station Blackout Rule, the B.5.b requirements [10 CFR

50.54(hh)] added after September 11, 2001, entail the development and implementation of

strategies that will maintain or restore containment, core cooling, and spent fuel pool cooling

capabilities following a loss of a large area of the plant infrastructure due to an explosion or fire.

Extensive Damage Mitigation Guidelines (EDMGs) were developed as part of this regulation to

help plants respond to such an event. However, there were no specific quality requirements to

ensure proper maintenance and training of these guidelines.

Instrumentation

Throughout the course of events at Fukushima, it became clear that accurate and up-to-

date measurements and readings of critical systems like the spent fuel pool and reactor core were

unknown, either due to the loss of power or from lack of instrumentation accessibility. It is

impossible to respond to any situation without access to the proper information. At this time, it is

unclear whether the Fukushima Daiichi control room even had instrument reading panels for the

spent fuel pools. Once the power was lost, so was the ability to obtain readings from the reactor

cores and spent fuel pools. A similar scenario could potentially occur in the United States, as it is

not mandated by the NRC that plants have spent fuel pool reading capability in the control room,

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and the site specific procedures may not provide guidance on how to obtain backup battery

power for these essential instruments during an extended blackout scenario.

Spent Nuclear Fuel Storage Considerations

Spent nuclear fuel is irradiated fuel that has already been used in the reactor to create

nuclear fission reactions. Although it is no longer useful in the reactor core, it must be properly

stored and cooled to prevent it from overheating and melting or even catching fire. The spent

fuel is housed under approximately 40-50 feet of water in the spent fuel pool, such that the

radioactivity levels at the surface of the water remain minimal. Spent fuel typically remains in

the spent fuel pool for 5 years or more before it may be transferred to dry cask storage. In dry

cask storage, the spent fuel is enveloped by inert gas and encased in steel and cement structures.

Dry cask storage is a passive system (not requiring electricity) that allows the spent fuel to be

naturally air-cooled as it sits outside in designated housing structures. A typical dry cask storage

container and a typical spent fuel pool are shown in Figures 3 and 4, respectively.

Figure 3: Diablo Canyon Dry Cask Storage Figure 4: Typical Spent Fuel Pool

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In comparing United States’ nuclear plants with the Fukushima Daiichi plant in Japan,

there is one important distinction in the storage of spent fuel. As Figure 5 depicts, a typical

United States’ spent fuel pool contains several times more fuel assemblies than any of the

Fukushima spent fuel pools. The Fukushima plant also had an additional shared spent fuel pool,

which is uncommon in the United States. Furthermore, the Japanese reprocess spent fuel,

resulting in a significant reduction in the overall amount of spent fuel onsite. In the United

States, with no reprocessing of or permanent repository for the spent fuel, spent fuel pools have

been re-racked and reorganized over the years to accommodate additional spent fuel. Dry cask

storage has only been used as a means to keep the spent fuel pools from reaching maximum

capacity. As Figure 6 shows, most United States’ spent fuel pools are nearing maximum capacity

levels.

Figure 5: Number of Spent Fuel Rods in Typical U.S. Plants and Daiichi Units 1-4

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Figure 6: High-Density Spent Fuel Pools at U.S. Nuclear Reactor Sites

The greatest concentrations of radioactivity present in the world are contained in United

States’ spent fuel pools. This spent fuel contains five to ten times more long-lived radioactivity

than the fuel in operation in the reactor core; and the amount of spent fuel continues to increase

with the addition of approximately 2,000 metric tons of spent fuel each year. As of December

2010, there was approximately 63,000 metric tons of spent fuel in spent fuel pools.5

The differences between United States’ spent fuel pools and the Japanese Daiichi spent

fuel pools, in terms of maintaining an appropriate water level in the pool, are significant. The

main distinction is that at a typical United States’ plant, it is unclear how quickly the water in the

spent fuel pool could evaporate, as it depends on how long the spent fuel has been in the pool

and how much spent fuel there actually is. The low density of spent fuel in Japanese plants could

provide many additional days before the water level is reduced enough to expose the spent fuel.

The heat given off by spent fuel decreases significantly over a rather short period of time. Spent

fuel is often in the spent fuel pool for 10 to 20 years, and at that point is producing relatively

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little heat to contribute to the evaporation of spent fuel pool water. However, it is still clear that

the higher density of United States’ spent fuel pools poses an increased risk in the ability to

respond to situations in which spent fuel pool cooling is compromised.

The cladding on spent fuel in the pool behaves differently than it does in the reactor. A

major concern for a spent fuel pool is the possibility of a zirconium fire. This is not typically a

concern for a reactor core, as the fuel cladding would melt rapidly once the water has evaporated

due to extremely high temperatures. In a spent fuel pool, on the other hand, the cladding does not

melt immediately (and may not melt), making a zirconium fire a possibility. Once the cladding is

exposed to air and steam it will react, increasing the amount of heat in the system and creating a

self-propagating fire. A zirconium fire could release significant amounts of Cesium-137 and

other radioactive isotopes into the environment.6

A worst case zirconium fire at any United States’ plant could result in a release of

radioactive material that rivals that of Chernobyl, if the building housing the spent fuel pool is

damaged. Intact, the containment building would prevent such a release from occurring. The

National Academy of Science performed a study on United States’ spent fuel pools and their

findings indicated that a partially drained or a fully drained spent fuel pool could result in a self-

propagating zirconium fire. Winds could easily spread the radioactive release over hundreds of

miles, should the building become damaged. As such, their recommendation was that spent fuel

more than 5 years old should be placed into dry cask storage.5 However, no such legislation or

regulation has been passed to address this critical issue.

Zirconium fires are not the only concerns in regard to spent fuel pools. In terms of

radioactive releases, the spent fuel pool does not have any protective containment (other than

water), like the reactor has. The water may help mitigate situations where cooling is lost, but it

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cannot protect against mechanical impacts on the fuel. At Fukushima, the explosions caused

cement and steel debris from the reactor building roof to crash down onto the refuel floor. Much

of this debris entered the spent fuel pool. Although it appears that any damage from this at

Fukushima was minimal, impacts from heavy objects could easily damage the spent fuel or the

pool itself.

If the falling debris damages the spent fuel pool—either by impact or cracking due to the

additional weight of the debris—the loss of coolant would also hasten the approach to critical

conditions. The United States has 31 elevated spent fuel pools (approximately 70-80 feet off the

ground), similar to the Fukushima Daiichi pools. If leakage occurs, it will fill the reactor

building, potentially leaching into the ground. It may also make the reactor building impassable

due to flooding, further preventing mitigating efforts. At Fukushima, approximately 1 meter of

spent fuel pool water was lost due to the earthquake. The water splashed out of the pool and onto

the refuel floor, contaminating that area as well as the employees on the floor. Spent fuel pools

are not surrounded by steel-lined concrete structures known as heavy containment like the

reactor is. The reactor building serves as the primary barrier from potential radiological releases.

Hardened Wet Well Vents

Fuel rods in a reactor are encased in cladding that is meant to prevent the release of

radioactive materials to the environment. In essence, its purpose is to contain the fuel. Once this

cladding reaches a certain temperature it can react with water, producing hydrogen gas. Nuclear

plants are designed to vent excess gases as a safety measure. Although all 23 Mark I containment

plants in the United States installed hardened vents after the NRC issued General Letter 89-16,

there is no regulation regarding the performance and testing of these vents to ensure they will

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operate appropriately when needed. At Fukushima, when the pressure within the reactor far

exceeded its design limits, there was a delay in making the decision to vent the gas buildup and

relieve the pressure. It is believed that the gas then leaked out of the reactor and built up in the

reactor buildings, ultimately causing the hydrogen gas explosions. This venting is critical,

especially for containment designs like Mark I and even Mark II that cannot withstand

significant buildup of internal pressure due to excess gas.

Multiple-Unit Sites in the United States

Multiple-unit nuclear sites pose different risks than single reactor sites. The two main

issues that arise are the distribution of plant personnel and the availability of critical emergency

components during a nuclear event. In the United States, there are 36 multi-unit nuclear sites. As

Fukushima demonstrated, a situation can develop in which several reactors and/or spent fuel

pools are in dangerous conditions. At a site with multiple units, there may be sufficient personnel

for normal operation and even for emergency conditions for a single reactor. However, it is

unclear whether multiple-unit plants have the necessary personnel and resources to react when

several units are in emergency conditions. When attention is divided, the results can be dire.

Additionally, if several reactors require the use of the same critical safety equipment—such as

emergency fire diesel pumps—it may become impossible to react effectively.

Probabilistic Risk Assessment

Probabilistic Risk Assessment, or PRA, is one of the primary ways in which nuclear

power plant risk is analyzed. This assessment takes the potential hazard as well as the potential

harm into account. The two methods to reducing risk include diminishing the likelihood that an

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event will happen and reducing the harmful effects should that event happen. Both the NRC and

the nuclear industry use PRA methods to analyze risk. The NRC identifies three specific levels

of PRA. A Level 1 PRA identifies the frequency of core damage through calculated risks from

known systems. A Level 2 PRA is a risk assessment that follows the assumption that the core has

been damaged. It is an effort to estimate the magnitude of the damage and the amount of

radioactive release that could occur. A Level 3 PRA is a risk assessment that assumes

containment has failed and estimates the potential harm to the public (including injuries) and the

economic implications of the containment failure. PRA methods are often used by the NRC to

assess the validity of regulatory safety margins. They are a critical component in developing

regulation with sufficient safety margins. Additionally, nuclear plants often conduct their own

PRA assessments in order to verify safe operation when modifications or maintenance is being

performed. When one system is out of operation, it increases the potential risk, which is why

these PRA assessments are of paramount importance.12

Maintenance of a Strong Nuclear Program in the United States

Looking to the future, Fukushima has demonstrated the importance of maintaining strong

nuclear engineering programs at the Department of Energy, universities, and research facilities.

Additionally, new nuclear generation technologies and their potential applications should be

incorporated in the United States. Support for newer, safer reactor designs, as well as research

and development into a variety of nuclear topics—such as more robust cladding material and fast

breeder reactors—must become a priority. This combination of strong nuclear engineering

support, new reactor designs, and research and development will allow the United States’ nuclear

industry to achieve its true potential.

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Further investment into the nuclear field is a must. Proper training of both nuclear

engineering and technical education programs is a necessity. It is of paramount importance that a

strong workforce pipeline exists from universities to the nuclear industry. Additionally, a

substantial knowledge transfer to the newer generations of the nuclear workforce must occur

prior to the looming retirement of the current workforce. The Nuclear Energy Institute estimates

that 39% of nuclear engineers are eligible for retirement within the next five years. If support for

such programs declines, so will the ability to employ proper personnel with the knowledge base

required to respond effectively in dire situations. Additionally, even if nuclear plants shut down

in the future, there will still be a need for this educated workforce to oversee reactor

decommissioning.

There are already several programs in place at colleges and universities across the

country. For instance, the Integrated University Program established in 2007 provides funding

from the Department of Energy, the Nuclear Regulatory Commission, and the National Nuclear

Security Administration for scholarships, fellowships, and research grants. Additionally, up to

20% of the Department of Energy Office of Nuclear Energy’s research and development budget

is typically designated for university research.

Research is critical for advancing the nuclear industry and making United States’ plant

designs safer. Safety has and always will be a top priority at all nuclear plants; however, the

events at Fukushima have demonstrated the importance of continually assessing and enhancing

safety features, as new technology is developed. To accomplish this, research in “new plant

designs that minimize waste and are even safer and more proliferation resistant than today’s

nuclear plant designs” is a must. The Department of Energy’s Office of Nuclear Energy, Science,

and Technology began a Generation IV reactor design initiative in 2002 in the hopes that these

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new designs could see commercial fruition by 2030. The Energy Policy Act of 2005 “set aside

$2.9 billion for nuclear research and development and hydrogen projects, including $1.6 billion

for general nuclear energy research and development, which supports the Generation IV reactor

initiative and other advanced technology programs.” Small modular reactors are another area of

research that has received support from Congress. These smaller reactors operate similarly to

large scale reactors, but require less upfront capital and can be manufactured in an assembly line

fashion. “Legislation recently introduced in the United States Senate, S. 512, the Nuclear Power

2021 Act, and S. 1067, the Nuclear Energy Research Initiative Improvement Act, would help

move two reactor designs through the safety certification process and study ways to reduce

manufacturing and construction costs.”

The nuclear field will continue to progress globally despite the events at Fukushima.

Many nations do not have an abundance of natural resources that would allow them to produce

large amounts of electricity independently of other nations. As such, nuclear energy is seen as

one of the sole means to achieving energy independence. Countries such as India and the United

Arab Emirates, for instance, are continuing to advance and expand their nuclear programs.

Nuclear energy must also progress in the United States for energy independence, cleaner energy

production methods, and for job creation. In his 2010 State of the Union Address, President

Obama stressed the importance of energy independence here in the United States. Additionally,

continued leadership in the international nuclear field is paramount if the United States wants to

continue to have a say in critical global issues such as nonproliferation. To maintain this

leadership, support of research and development of newer and safer reactor designs is a

necessity. At present, there is no other clean air energy production method that could become a

base supply of electricity to support a transition to renewable energy production in the future. As

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Senator Mark Udall (D-Colorado) stated, “Nuclear (energy) is among the few low-carbon, large-

scale sources of baseload power that we know how to build today—and small reactors have the

potential to make nuclear power more cost-efficient and secure.” In terms of job creation, new

nuclear energy yields more new jobs than additional coal, wind, and natural gas combined, as

shown in Figure 7 below.

Figure 7: Jobs Created for Operating Energy Plants

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Policy Alternatives Risk Assessment

Risk assessment is key to analyzing the safety of United States’ nuclear plants.

Rulemaking in regards to this would be two fold, including Level 3 Probabilistic Risk

Assessment as well as multiple-unit site Probabilistic Risk Assessment. As previously discussed

in the background section, a Level 3 PRA requires analysis of events to the extent where there is

significant release of radiation and/or radioactive materials to the environment and the public. It

considers both the health and land effects of this release. Most regulation at present is based

solely on the health effects of containment failure. After Fukushima, it is clear that the land

effects are also important. In Japan, there was a significant radioactive release into the air and

ocean and many miles of land were damaged. These releases should be addressed. The last Level

3 PRA assessment was completed in the 1980s. Rulemaking requiring a Level 3 PRA would

enhance the NRC’s ability to pass additional effective regulations that would ensure the safety of

United States’ nuclear plants.

Following the events at Fukushima, it is now clear that multiple unit event analysis must

be considered in the risk assessments of each plant. Rulemaking requiring risk assessment of an

event where several units are affected is critical to improving the safety of these multi-unit

plants. The availability of resources and personnel play a tremendous role in the operational risk

of a site. Should a multi-unit event occur, the personnel must have the ability to obtain the

necessary equipment, effectively use the necessary personnel trained in accident mitigating

strategies, and act on several units at once. Ultimately, this will aid in determining appropriate

mitigating measures, guidelines, procedures, and training.

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Offsite Power Loss

Offsite power loss rulemaking must include four distinct pieces: coping time, diesel fuel

availability and storage, instrumentation, and Severe Accident Management Guidelines. Coping

times vary from plant to plant based on certain parameters that determine the ability to restore

power. New coping times should be extended for all nuclear plants. Additionally, diesel fuel

should be stored in a seismically secure and flood proof buildings, so it remains accessible

regardless of circumstances. Plans for obtaining additional offsite fuel should also be required.

Instrumentation

The ability to obtain critical readings during a significant event is paramount. As

demonstrated at the Fukushima site, it is difficult to react promptly and properly without

knowing the status of certain critical systems. Additionally, such measurements as water level

and temperature in the spent fuel pool would also aid in mitigating any potential spent fuel

problems. At the Fukushima Daiichi plant, the operators did not know the condition of the spent

fuel pools once the water fell below a specific level, and they were unable to enter the reactor

building to look at the pools due to high levels of radioactivity. Rulemaking would require that

nuclear plants have some method of supplying power to critical instrumentation once the backup

batteries run out.

Quality Assurance Program for EDMGs and SAMGs

Rulemaking would include the mandatory use, exercise, and training of plant specific

Extensive Damage Mitigation Guidelines, or EDMGs, and Severe Accident Management

Guidelines, or SAMGs. EDMGs were created after September 11, 2001 “to maintain or restore

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capabilities for core cooling and containment and spent fuel pool cooling under the

circumstances associated with the loss of large areas of the plant due to a fire or explosion.”

(Nuclear Regulatory Commission17) The primary objectives of SAMGs are three-fold: to prevent

further core degradation, to maintain containment, and to reduce the amount of radioactivity that

is released. SAMGs are currently a voluntary initiative and are not routinely inspected by the

NRC. EDMGs, on the other hand, are a mandatory requirement; however, there is no inclusion

of a quality control method to maintain updated and properly exercised EDMGs. Rulemaking

would place EDMGs and SAMGs under the routine inspection of the NRC, ensuring the

uniformity of safety, procedures, and training, as well as a continuing mechanism to ensure

quality standards for these guidelines.

Dry Cask Spent Fuel Storage Legislation

The storage of spent fuel has always been a controversial issue in the United States. At

this point, it is unclear when or if a national spent fuel repository will be created. Although the

NRC currently licenses dry cask storage, there are many state and local government impediments

to dry cask storage. Legislation that places dry cask storage solely under the discretion of the

NRC would allow nuclear plants to use this safer method of storage instead of continuing to fill

the spent fuel pools.

BWR Mark I and Mark II Venting Rulemaking

In the 1980s, the NRC’s Generic Letter 89-16 encouraged Mark I containment plants to

have hardened vents installed. Mark I BWRs cannot handle the pressure buildup of increased

steam during an event where decay heat (heat still being produced after reactor shutdown)

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removal capabilities are lost. In order to maintain the integrity of the reactor vessel, steam (and

pressure) must be vented out of reactor vessel through pipes, where it is filtered and then

released into the atmosphere via the stacks. These pipes must be hardened so they will not

rupture under the pressure of the steam. There is no uniformity in design, performance, or

periodic testing of these hardened vents. Rulemaking assessing the performance and periodic

testing of these hardened vents is a necessity in preventing pressure buildups in Mark I and Mark

II containments.

Seismic and Flood Hazard Rulemaking

As technology progresses, so does the ability to model potential seismic and flood

hazards for each region. As the NRC’s Near Term Task Force findings showed, some nuclear

plants have increased risks for seismic activity since the time in which the plants were licensed.

As Figure 8 below demonstrates, most nuclear plants (green dots) in the United States are

actually located far away from modern earthquake locations (red dots). There are, however, a

few plants located in close proximity to these earthquake locations. Rulemaking requiring

nuclear plants to reevaluate their seismic and flood hazards every 10 years, as recommended by

the Task Force, would ensure the maintenance and updating of necessary equipment and even

the current design basis of the plant. Rulemaking would also include additional seismic

requirements for certain equipment. Fires caused by seismic activity could result in failures of

pivotal systems. Therefore, it is necessary to ensure fire mitigating equipment is designed to

withstand a major earthquake and is stored somewhere accessible following such an earthquake.

The NRC findings from Temporary Instruction 183 showed that the accessibility and operability

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of certain necessary pieces of equipment was not adequate at all plants. As such, rulemaking on

this matter should be made a priority.

Figure 8: Locations of Nuclear Plants and Significant Earthquakes since 1973

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Recommendations

As the United States continues to assess the implications of the events that transpired at

Fukushima, it is necessary to amend current regulation with more specific standards regarding

safety and to complete all necessary studies and assessments in order to support any new

regulations. It is in the best interest of the United States and of the public to enhance the safety

features of all 104 nuclear reactors by new legislation and rulemaking.

Recommendation #1: Emergency Preparedness Exercise

A review of post-accident environmental monitoring and local, state, and federal agency

interactions should be performed to address the federal government’s responsibilities during a

nuclear event. As Fukushima displayed, communication between TEPCO and the federal

government was delayed. As a result, a substantial amount of time passed before certain

decisions were made and accurate environmental data regarding radioactive releases was

obtained. Prompt action and effective communication by the appropriate federal agencies are of

paramount importance after a significant event. Emergency response agencies must have

communication with plant personnel in order to actively respond and perform critical post-

accident monitoring. As such, appropriate coordination between the involved emergency

response agencies to conduct additional exercises and training on response measures should be

undertaken as often as deemed appropriate to ensure adequate response can be achieved in a real

event.

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Recommendation #2: Instrumentation Rulemaking

All nuclear plants must have the ability to supply power to reactor and spent fuel pool

instrumentation during extended blackout situations. This may be through the use of backup

batteries and other potential energy supply mechanisms. During a station blackout, such as the

one that occurred at Fukushima, the Unit 4 spent fuel pool conditions were unknown, until the

time at which a camera was able to get inside the building. It is important to have the ability to

obtain up-to-date and accurate data regarding plant conditions. Rulemaking should address this

lack of instrumentation as well as determine the appropriate level of backup power required for

instrumentation.

Recommendation #3: Seismic and Flood Hazard Rulemaking

Rulemaking that requires a review of seismic and flood hazards at each nuclear plant

every 10 years would allow the Nuclear Regulatory Commission to properly address any new

potential dangers. New seismic and flood models would help provide more accurate safety

margins for operations. In order to address seismically induced fires, fire mitigating equipment

should be stored in close proximity and in seismically secure and flood proof locations. Multiple

unit nuclear plants must have independent fire mitigating equipment for each reactor and each

spent fuel pool. As the events at Fukushima showed, all units could be impacted by a large event

and may be in need of simultaneous emergency equipment usage. Additionally, the accessibility

and functionality of these pumps should be reviewed on a yearly basis to ensure that

modifications to the plant will not interfere with the ability to act promptly.

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Recommendation #4: Dry Cask Storage Legislation

Spent fuel being stored in the spent fuel pool should be removed and stored in dry cask

storage containers as soon as safely achievable, or approximately 5 years. This means, that at any

given time, should a natural disaster strike, less fuel would be in the spent fuel pool, thereby

decreasing the vulnerability of the plant. This recommendation requires legislation regarding the

ability to have additional dry casks on site at each plant. Many states have impediments in place

to prevent dry cask storage altogether or to prevent new dry storage casks. Legislation on the

matter would be of tremendous benefit to the nuclear industry and provide the necessary federal

oversight.

Recommendation #5: Quality Assurance Program

Rulemaking must place Extensive Damage Mitigation Guidelines, or EDMGs, and

Severe Accident Management Guidelines, or SAMGs, under the routine inspection of the NRC,

to ensure there is uniformity of safety, procedures, and training. A quality assurance program

would require the NRC and nuclear plants to maintain updated EDMGs and SAMGs that would

better prepare expedient reaction during a significant nuclear event.

Recommendation #6: Nuclear University Programs and Research and Development

As previously discussed, the United States should continue to support nuclear university

and community college programs, as well as fund nuclear research and development. Together,

these will help to provide the future workforce of the nuclear industry as well as usher in a newer

and safer generation of nuclear reactors and plants into the United States. Funding appropriations

for research and development through scholarships, fellowships, faculty development grants, and

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infrastructure grants would further develop the nuclear industry and support the United States’

move toward energy independence and clean air energies.

Works Cited

1. Nuclear Regulatory Commission (April 29, 2011), “Regulatory Decision-Making in the

Wake of Fukushima”. Retrieved from Nuclear Regulatory Commission:

http://www.nrc.gov/about-nrc/organization/commission/comm-william-

ostendorff/ostendorff-eei-04292011.pdf

2. International Atomic Energy Agency (1990), “INES, International Nuclear and Radiological

Events Scale”. Retrieved from International Atomic Energy Agency:

http://www.iaea.org/Publications/Factsheets/English/ines.pdf

3. Nuclear Energy Institute (2010), Resources and Stats for U.S. Nuclear Power Plants.

Retrieved from Nuclear Energy Institute:

http://www.nei.org/resourcesandstats/nuclear_statistics/usnuclearpowerplants/

4. Nuclear Energy Institute, Institute of Nuclear Power Operators, and Electric Power Research

Institute (June 8, 2011), “The Way Forward: US Industry Leadership in Response to the

Events at the Fukushima Daiichi Nuclear Power Plant”

5. Institute for Policy Studies, Robert Alvarez (May 2011), “Spent Nuclear Fuel Pools in the

U.S.: Reducing the Deadly Risks of Storage”

6. Nuclear Energy Agency/ Organization for Economic Cooperation and Development (2005),

“The Safety of the Nuclear Fuel Cycle”

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7. California Energy Commission (October 2008), “AB 1632 Assessment of California’s

Operating Nuclear Plants”

8. Nuclear Regulatory Commission (June 17, 2011), “10 CFR 50, Appendix A—General

Design Criteria for Nuclear Power Plants”. Retrieved from Nuclear Regulatory Commission:

http://www.nrc.gov/reading-rm/doc-collections/cfr/part050/part050-appa.html

9. Government of Japan/ Nuclear Emergency Response Headquarters (June 2011), “Report of

Japanese Government to the IAEA Ministerial Conference on Nuclear Safety – The Accident

at TEPCO’s Fukushima Nuclear Power Stations”

10. Nuclear Regulatory Commission, Idaho National Laboratory (December 2005),

“Reevaluation of Station Blackout Risks at Nuclear Power Plants”

11. Allegheny Technologies (2003), “Reactor Grade Zirconium Alloys for Nuclear Waste

Disposal”.

12. Nuclear Regulatory Commission (October 2007), “Probabilistic Risk Assessment”

13. Nuclear Regulatory Commission (June 15, 2011), “Briefing on the Progress of the Task

Force Review of NRC Processes and Regulations Following the Events in Japan”

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14. Nuclear Regulatory Commission (June 23, 2011), “Briefing to the Advisory Committee on

Reactor Safeguards on the NRC Task Force and Actions Following the Events in Japan”

15. Nuclear Regulatory Commission (March 23, 2011), Temporary Instruction 183, “Followup

to the Fukushima Daiichi Nuclear Station Fuel Damage Event”

16. Nuclear Energy Institute (June 27, 2011), “Eight of 10 Residents Near U.S. Nuclear Power

Plants Favor Use of Nuclear Energy”

17. Nuclear Regulatory Commission Near Term Task Force (July 12, 2011), “Recommendations

for Enhancing Reactor Safety in the 21st Century”

18. Nuclear Energy Institute (June 2011), “Emergency Preparedness at Nuclear Energy

Facilities”