NUCLEAR 

REGULATORY 

COMMISSION

Oversight and Status 

of Implementing a 

Risk-Informed 

Approach to Fire 

Safety

Report to Congressional Requesters

October 2012

GAO-13-8

United States Government Accountability Office

GAO
United States Government Accountability Office

Highlights of GAO-13-8, a report to 

congressional requesters

October 2012

NUCLEAR REGULATORY COMMISSION 

Oversight and Status of Implementing a Risk- Informed Approach to Fire Safety

Why GAO Did This Study

In 1975, a fire at a nuclear power plant 

damaged critical control cables and 

hampered operators’ ability to monitor

the status of the plant’s reactor. NRC 

subsequently issued deterministic fire 

safety regulations for plants to follow, 

but differences in plant design, coupled 

with changes in NRC guidance, made 

it difficult for most plants to meet the 

regulations without seeking numerous 

exemptions. In 2004, NRC issued a 

regulation permitting plants to 

voluntarily transition to risk-informed 

fire protection requirements. This new 

approach mirrors NRC’s efforts to 

adopt a more risk-informed regulatory 

approach to nuclear safety in general. 

In 2008, GAO reported on three key 

fire safety issues and recommended 

NRC take action to address them.

GAO was asked to examine (1) NRC’s 

progress in resolving the long-standing 

fire safety issues raised in GAO’s 2008 

report at plants remaining under the 

deterministic approach and at those 

plants transitioning to the risk-informed 

approach; (2) the potential benefits of 

transitioning to a risk-informed 

approach and the basis for NRC’s 

decision to make adoption of this 

approach voluntary; and (3) 

challenges, if any, in efforts to 

transition to a risk-informed approach 

in regulating fire safety. GAO reviewed 

documents; analyzed responses from 

operators at a nonprobability sample of 

12 nuclear plants and from nine 

consultants or academic experts on fire 

safety issues and risk-informed 

regulations; and interviewed NRC, 

industry, and public interest group 

representatives.

GAO is not making recommendations 

in this report. NRC found the report to 

be accurate and complete. 

What GAO Found

The Nuclear Regulatory Commission (NRC), together with plant operators, has 

made progress in resolving three fire safety issues raised in GAO’s 2008 report 

by implementing GAO’s recommendations or taking other actions. NRC 

implemented the recommendation on multiple spurious operations (malfunctions 

caused by fire that could cause safety-related equipment to malfunction) by 

issuing new guidance or requiring additional modifications at the 36 plants with 

57 reactors operating under deterministic regulations. NRC did not implement the 

recommendations to address the effectiveness of fire wraps or the extended use 

of interim compensatory measures plants use instead of repairing or replacing 

damaged safety equipment; however, NRC did take some actions, including 

(1) evaluating and reporting on corrective actions plants used to mitigate safety 

concerns associated with fire wraps and (2) developing metrics to gauge the 

progress of NRC’s staff in resolve underlying issues related to the extended use 

of compensatory measures. According to NRC, plants transitioning to a riskinformed fire safety approach are continuing to resolve these issues through 

modifications and analyses required as part of the transition process. GAO 

visited two transitioning plants and observed examples of such modifications. 

According to NRC officials, plant operators, and others GAO spoke with, the riskinformed regulatory approach to fire safety offers benefits over the deterministic 

approach, but NRC made adoption of the risk-informed approach voluntary 

because it considers plants that meet deterministic requirements to be safe. NRC 

officials stated that the risk-informed approach (1) will provide plant operators 

with information to help them quantifiably reduce risk and with flexibility in areas 

that do not affect risk and (2) allow operators to more easily demonstrate 

compliance with simplified licensing requirements. According to some of the plant 

operators, consultants, and experts GAO spoke with, plants will improve their 

safety using the risk-informed approach. NRC considered mandating the riskinformed approach, but it did not do so because of uncertainties over whether the 

agency could determine if the approach could improve protection of health and 

safety enough to impose new regulations. NRC considers plants that meet 

deterministic requirements to be safe, including plants that do so through 

approved exceptions to these requirements; thus, it does not plan to further 

analyze whether the risk-informed approach should be mandatory.

Plant operators, consultants, and experts GAO spoke with identified three 

challenges that may affect NRC’s transition schedule and the number of plants 

that ultimately transition to the risk-informed approach. First, transition costs have 

been higher than initially expected, and operators from all of the nontransitioning 

plants GAO contacted cited this as reason they are remaining under the 

deterministic approach. Second, according to some operators, consultants, and 

experts, the absence of fire data may hinder the development of realistic risk 

assessments and contribute to overly conservative NRC risk assessment 

guidance, potentially leading to a misallocation of resources. NRC and other 

stakeholders disagreed with this assessment. Third, few people have expertise in 

risk analysis and fire modeling, and some operators, consultants, and experts 

expressed concern that the need for such expertise could compete with other 

safety-related efforts. However, most consultants and experts GAO spoke with 

believed that the number of people with expertise will be sufficient to support the 

transition effort.

View GAO-13-8. For more information, contact 

Frank Rusco at (202) 512-3841 or 

ruscof@gao.gov
Page i GAO-13-8 Nuclear Plant Fire Safety

Letter 1 

Background 5

NRC Has Taken Steps to Resolve Long-standing Fire Safety Issues 12

Benefits Cited in the Risk-Informed Fire Safety Approach, but NRC 

Considers Plants That Meet the Deterministic Approach to Be 

Safe 17

Plants Transitioning to the Risk-Informed Approach Face Three 

Key Challenges 22

Agency Comments and Our Evaluation 25

Appendix I Objectives, Scope, and Methodology 27

Appendix II List of Consultants and Experts Contacted for This Report 31

Appendix III Schedule for Plants Transitioning to a Risk-Informed Approach to 

Fire Safety 32

Appendix IV Comments from the Nuclear Regulatory Commission 34

Appendix V GAO Contact and Staff Acknowledgments 35

Figures

Figure 1: Process for Demonstrating Fire Safety Compliance under 

the Deterministic Approach 7

Figure 2: Process for Demonstrating Fire Safety Compliance under 

the Risk-Informed Approach 9

Figure 3: Nuclear Power Plants with Reactors Transitioning to the 

Risk-Informed Approach or Remaining under the 

Deterministic Approach 12

Figure 4: Incipient Fire Detection Device 17

Contents
Page ii GAO-13-8 Nuclear Plant Fire Safety

Abbreviations

NIST National Institute for Standards and Technology

NRC Nuclear Regulatory Commission

NFPA National Fire Protection Association

PRA probabilistic risk assessment

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Page 1 GAO-13-8 Nuclear Plant Fire Safety

United States Government Accountability Office

Washington, DC 20548

October 22, 2012

The Honorable Barbara Boxer

Chairman

Committee on Environment and Public Works

United States Senate

The Honorable Edward J. Markey

House of Representatives

On March 22, 1975, a worker testing for air leaks within a building 

housing a nuclear reactor at the Browns Ferry nuclear power plant in 

Alabama inadvertently started a fire when the candle he was using ignited 

nearby electrical cables. The fire burned for 7 hours and damaged cables 

for electrical power, control systems, and instrumentation, and impaired 

the reactor’s cooling systems. The fire also prevented plant operators 

from monitoring the reactor’s status normally. In the years following this 

event, the Nuclear Regulatory Commission (NRC), which licenses and 

regulates nuclear reactors,1

 

1

NRC issues licenses for individual nuclear reactors, one or more of which may be located 

at a particular site, which is generally called a plant. In this report, we use the term “plant” 

to describe a site with nuclear reactors, because most industry officials we met with 

discussed operations at the plant level. However, in instances in which we discuss NRC 

guidance or regulations that relate to individual reactors, we use the term “reactors.” When 

referring to the personnel who operate a reactor or a plant, and who are responsible for 

implementing regulations, we use the term “plant operators.” 

worked to develop a regulatory approach to 

fire safety, and in 1980 the agency promulgated fire safety regulations 

(referred to as “Appendix R”) for licensed commercial nuclear power 

plants that were operating prior to January 1, 1979. These regulations 

establish the design requirements for nuclear reactors at commercial 

power plants to mitigate the effects of a fire on power plant operators’ 

ability to shut down a reactor safely. Commercial nuclear power plants 

that were licensed to operate on or after that date are not subject to these 

regulations, but NRC included licensing conditions—which we refer to as 

licensing requirements—that are similar to the regulations in each of the 

newer plants’ operating licenses. These regulations and requirements are 

considered to be prescriptive (referred to as “deterministic”). In this report, 

we refer to Appendix R and these similar conditions for operating licenses 

NRC issued since January 1, 1979, as the deterministic approach. The 

deterministic approach, which NRC has also used to oversee nuclear 

 
 

Page 2 GAO-13-8 Nuclear Plant Fire Safety

power plant safety in areas other than fire protection, establishes a 

specific set of potential accidents, the consequences of which a nuclear 

power reactor must be designed to prevent or mitigate to protect public 

health and safety. It also establishes requirements for engineering safety 

margins and quality assurance standards for the design, manufacture, 

and construction of nuclear power reactors.

In the 1990s, NRC’s oversight of nuclear reactor safety began moving 

from the deterministic approach to a risk-informed, performance-based 

approach to regulatory decision making that was being implemented in 

phases, according to NRC documents. Since 2000, NRC has worked with 

the Nuclear Energy Institute,2 the National Fire Protection Association 

(NFPA),3 and others to develop a new risk-informed, performance-based 

fire safety regulation, which endorsed key aspects of a fire safety 

standard issued by NFPA. (Hereafter, we will refer to the “risk-informed, 

performance-based approach” as the “risk-informed approach.”) NRC 

issued this risk-informed regulation in 2004;4

In June 2008, we reported on NRC’s oversight of fire safety at nuclear 

power plants and described three long-standing fire safety issues facing 

the agency and the nuclear industry.

it represents an alternative 

approach to the deterministic fire protection regulations. NRC has allowed 

nuclear power plant operators to voluntarily adopt the fire protection 

requirements in the new regulation or to continue to comply with the 

deterministic fire safety regulations and licensing requirements. In 2005, 

NRC initiated a pilot program at two nuclear power plants that 

volunteered to transition to the risk-informed fire safety approach.

5

 

2

The Nuclear Energy Institute is the policy organization for the nuclear technologies 

industry.

First, we reported that a fire at a 

nuclear power plant could cause short circuits resulting in multiple circuit 

failures, known as multiple “spurious operations,” in systems needed to 

3

An international nonprofit organization, NFPA develops, publishes, and disseminates fire 

prevention and safety standards.

4

NRC, in 69 Fed. Reg. 33536 (June 16, 2004)(codified at 10 C.F.R. § 50.48(c)), endorsed 

the use of key aspects of National Fire Protection Association, NFPA-805, PerformanceBased Standard for Fire Protection for Light Water Reactors Electric Generating Plants, 

2001 Edition (Quincy, Massachusetts: 2001).

5

GAO, Nuclear Safety: NRC’s Oversight of Fire Protection at U.S. Commercial Nuclear 

Reactor Units Could Be Strengthened GAO-08-747(Washington, D.C.: June 30, 2008).
 

Page 3 GAO-13-8 Nuclear Plant Fire Safety

safely shut down a plant’s nuclear power reactor.6 At the time of our 

report, plant operators typically accounted only for spurious operations 

that occur one at a time or in isolation from one another, although industry 

tests conducted in 2001 demonstrated that spurious operations could 

occur simultaneously or in rapid succession. Second, we reported that 

NRC had not resolved uncertainty about the effectiveness of some types 

of fire-protection barriers (known as fire wraps) used to protect cables that 

are important for safely shutting down a nuclear reactor. Third, we 

reported that some plant operators had used temporary measures that 

that they could take without prior approval to compensate for equipment 

that needs to be repaired or replaced (compensatory measures) for an 

extended period of time rather than conducting needed maintenance, a 

practice that could degrade nuclear fire safety.7 For example, some plants 

had adopted fire watches, in which teams of plant employees are either 

posted continuously in a single location in a plant or rove throughout the 

plant to detect signs of fires. We reported that, at one nuclear power plant 

we visited, plant operators used fire watches for more than 5 years 

instead of replacing faulty seals to cover openings in structural barriers. 

We made three recommendations to address these long-standing fire 

safety issues, and we discuss actions NRC took to address them in the 

report.8

In this context, you asked us to follow up on our 2008 report on fire 

safety. Our objectives were to provide information on (1) NRC’s progress 

in resolving the long-standing fire safety issues raised in our 2008 report 

at plants remaining under the deterministic approach and at those plants 

transitioning to the risk-informed approach; (2) the potential benefits of 

transitioning to a risk-informed approach and the basis for NRC’s decision 

 

6

In our 2008 report, we referred to these as multiple spurious actuations, which is another 

term to describe the same phenomenon.

7

NRC considers compensatory measures that are in place longer than 18 months to be 

extended.

8

We also made a fourth recommendation based on our finding that NRC did not have a 

comprehensive database that aggregated information on exemptions (known as 

exemptions and deviations) to licensing requirements, or the extended use of 

compensatory measures that could facilitate the study of compliance trends. In response 

to this recommendation, NRC developed an online document that identifies records of 

approved exemptions in NRC’s public database. We did not conduct additional work for 

this review on that recommendation.
 

Page 4 GAO-13-8 Nuclear Plant Fire Safety

to make adoption of this approach voluntary; and (3) challenges, if any, in 

efforts to transition to a risk-informed approach in regulating fire safety.

To obtain information on NRC’s progress in resolving the fire safety 

issues raised in our 2008 report, we reviewed regulations, guidance 

documents, and periodic reports from NRC and industry. In addition, we 

interviewed officials from NRC and representatives from industry and 

public interest groups. We also conducted semistructured interviews with 

plant operators about conditions at a nonprobability sample of six plants 

remaining under the deterministic fire safety approach and six plants 

transitioning to the risk-informed fire safety approach to obtain information 

about fire protection at both types of plants.9 Because the plants included 

in our review are a nonprobability sample that we selected to represent a 

mix of reactor types and ages, the information gathered from these plants 

cannot be generalized to the entire population of plants, or the nuclear 

power industry as a whole, but it does allow us to make qualified 

comparisons between different groups of plants and to discuss issues 

faced by each group. To obtain information on the potential benefits of 

transitioning to a risk-informed approach and the basis for NRC’s decision 

to make adoption of this approach voluntary, we reviewed NRC 

regulations, standards, and guidance on risk-informed regulation, 

probabilistic risk assessment and the use of fire modeling at nuclear 

power plants. We reviewed industry guidance documents and policy 

statements on the transition. We also conducted a semistructured 

interview with a total of nine nuclear engineering consultants and 

academic experts with previous or current experience in the nuclear 

power industry—six nuclear engineering consultants currently employed 

at private firms, one consultant currently employed at a Department of 

Energy national laboratory, and two academic experts with experience in 

conducting probabilistic risk assessment, fire modeling, or both. Officials 

from NRC and the National Institute of Standards and Technology (NIST), 

industry representatives, as well as operators of the 12 plants we 

consulted, also provided their insights into the strengths and weaknesses 

of the deterministic and risk-informed approaches to fire safety.10

 

9

The 12 plants we contacted house a total of 24 of the nation’s 104 nuclear reactors.

We 

10NIST developed one of the fire models currently used at nuclear power plants, and 

provided extensive modeling and experimentation expertise in NRC’s evaluation of fire 

models used at nuclear power plants. Fire models can help determine how the fire may 

grow in time and affect structures or systems important for the safe shutdown of a plant.

Fire modeling is used in conjunction with probabilistic risk assessments in the riskinformed fire safety approach. 
 

Page 5 GAO-13-8 Nuclear Plant Fire Safety

conducted site visits to the two nuclear power plants that participated in 

the pilot program for the risk-informed fire safety approach. To obtain 

information on challenges, if any, in efforts to transition to a risk-informed 

approach in regulating fire safety, we reviewed documentation related to 

NRC’s decision to make the adoption of the risk-informed approach 

voluntary. We reviewed NRC regulations, guidance, and policy 

documents on the deterministic and risk-informed fire safety approaches. 

We also summarized the results of our semistructured interviews with the 

nine nuclear engineering consultants and academic experts we contacted 

regarding their views on the benefits of the deterministic and riskinformed approaches to fire safety. We also attended relevant 

presentations at NRC’s March 2012 Regulatory Information Conference, 

and we observed multiple NRC public meetings with industry concerning 

issues related to the risk-informed approach to fire safety. Appendix I 

presents a more detailed description of our scope and methodology, and 

appendix II lists the names and affiliations of the nine consultants and 

experts we interviewed.

We conducted this performance audit from September 2011 to October 

2012 in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 

our findings and conclusions based on our audit objectives. We believe 

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives.

This section discusses the development of NRC’s fire safety regulations, 

NRC’s adoption of risk-informed regulation, and the status of the nuclear 

industry’s adoption of the risk-informed fire safety approach.

NRC’s deterministic fire safety approach and its risk-informed fire safety 

approach contain requirements that plants’ fire protection programs have 

defense-in-depth objectives in areas important to fire safety.11

 

11According to NRC documents, “defense-in-depth” is a way of designing and operating 

nuclear power reactors that focuses on creating multiple independent and redundant 

layers of defense to compensate for potential human and mechanical failures so that no 

single layer, no matter how robust, is exclusively relied upon.

Under both 

approaches, plants must meet the following objectives: (1) prevent fires 

Background 

NRC’s Fire Safety 

Regulations 
 

Page 6 GAO-13-8 Nuclear Plant Fire Safety

from starting; (2) detect rapidly, control, and extinguish promptly those 

fires that do occur; and (3) provide protection for structures, systems, and 

components important to safety so that a fire that is not promptly 

extinguished by the fire suppression activities will not prevent the safe 

shutdown of the plant. The two approaches provide different methods for 

plants to demonstrate defense-in-depth capabilities. According to NRC 

officials and nuclear industry representatives, no fire since the Browns 

Ferry fire in 1975 has threatened a U.S. nuclear reactor’s ability to safely 

shut down.12

NRC’s deterministic fire safety approach requires that power plant 

operators ensure that at least one system of electric cables and 

equipment is available to safely shut down a reactor if a fire occurs. To 

meet requirements under the deterministic approach, these operators 

must, among other things, separate redundant systems, either by 

distance or fire resistant barriers, such as a fire resistant wall or floor, or 

by a material (fire wrap) that protects important cables and, in some 

cases, operators must install fire detection and automatic suppression 

systems. The requirements also specify the amount of space between 

redundant systems or how long fire barriers should be able to withstand 

fire.13

 

12In our 2008 report, we reported that from January 1995 through December 2007, 

operators at 54 plants had informed NRC of 125 fires at their plants. From January 2008 

through November 2011, operators at 22 plants reported an additional 27 fires to NRC. 

For example, fire barriers must also be able to withstand fire for at 

least 1 hour in areas with automatic fire suppression systems and fire 

detectors or for at least 3 hours where such features are not present. If 

these requirements are not met or if a redundant system required for 

shutdown could be damaged by fire suppression activities or operation of 

the fire suppression system, NRC requires an alternative dedicated 

shutdown capability. Figure 1 shows the process a plant operator uses to 

demonstrate fire safety compliance under the deterministic approach.

13Specifically, the deterministic fire safety approach requires nuclear reactors to have at 

least one redundant system of electric cables and equipment available to safely shut down 

the reactor. When two systems are in the same area of a nuclear reactor building, the 

regulations require that they be (1) separated horizontally by more than 20 feet with no 

intervening combustibles or fire hazards and for the area to have fire detectors and 

automatic fire suppression systems, or (2) separated by a fire barrier, such as a fireproof 

wall or floor, or by a material (fire wrap) that can withstand fire for 3 hours, or (3) enclosed 

by a fire barrier or material that can withstand fire for 1 hour and for the area to have fire 

detectors and an automatic fire suppression system. 

NRC’s Deterministic Approach 
 

Page 7 GAO-13-8 Nuclear Plant Fire Safety

Figure 1: Process for Demonstrating Fire Safety Compliance under the Deterministic Approach

a

“Containment” refers to structures, systems, or components provided to prevent or mitigate the 

release of radioactive materials.

b

Over the years, NRC has approved exemptions or deviations from this 

deterministic approach for units that could not meet the fire safety 

requirements if the units could otherwise demonstrate the ability to safely 

shut down. Plants follow the following processes, as applicable:

A “radiant energy shield” is a device used to protect components from the effects of radiant heat 

generated by a fire.
 

Page 8 GAO-13-8 Nuclear Plant Fire Safety

• Exemption process. Under this process, plant operators could obtain 

an exemption from the deterministic requirements if they could 

demonstrate fire safety through methods or features other than those 

explicitly stated in the regulations.

• Deviation process. Some of the reactors that came online after NRC 

had defined the deterministic approach still could not meet the 

requirements. In such cases, NRC allowed operators to seek 

deviations from their licensing requirements if they could demonstrate

an acceptable alternate approach to fire safety.

In part because of variations among plant designs and different 

interpretations of fire safety regulations between industry and NRC, the 

agency continued to issue updated guidance related to the deterministic 

regulations, according to NRC and industry documents. However, in 

2004, NRC reported that the processing of exemption and deviation 

requests had placed a “significant” burden on the resources of the agency 

and the nuclear industry.14

In response to charges that the processes for granting exemptions and 

deviations under the deterministic approach were burdensome, NRC 

issued a regulation in 2004 permitting plants to voluntarily transition to 

risk-informed fire protection requirements. Under this approach, a plant 

operator adopts performance goals, objectives, and criteria for fire safety 

that are defined by the fire protection standard issued by NFPA. The 

operator can use probabilistic risk assessments (PRA) and fire models, 

among other tools, to meet the performance criteria. A PRA is a 

systematic assessment of what can go wrong, its likelihood, and its 

potential consequences to determine quantitative estimates of a particular 

risk, such as a fire safety risk. Fire models are mathematical predictions 

of fire growth, environmental conditions, and potential effects on 

structures or systems. Figure 2 illustrates how a plant demonstrates fire 

safety compliance under the risk-informed approach.

NRC also acknowledged that industry 

representatives and some members of the public described the 

deterministic requirements as an “unnecessary regulatory burden.” As of 

April 2012, NRC had granted more than 900 exemptions and deviations 

from the deterministic fire safety approach, according to NRC documents 

and officials.

 

1469 Fed. Reg. 33536, 33537 (June 16, 2004).

Risk-Informed Approach
 

Page 9 GAO-13-8 Nuclear Plant Fire Safety

Figure 2: Process for Demonstrating Fire Safety Compliance under the Risk-Informed Approach

Note: Plant operators use fire probabilistic risk assessments and fire models, among other risk 

analysis tools, throughout the process to demonstrate compliance.

Nuclear power plant operators can choose to make a transition from 

using the deterministic approach to the risk-informed approach. In doing 

so, they can conduct a PRA that is subsequently reviewed by teams of 

experts from other plant operators and consulting firms that are not 

involved in developing the PRA under review. After the PRA is reviewed, 

the transitioning plant requests that NRC amend the plant’s operating 

license. NRC staff review the amendment request and, if necessary, 

request additional information from plant operators and conduct audits of 

transition documents to ensure that the plant has conducted the 

necessary tasks. If NRC approves the license amendment request, it will 

issue a final report evaluating the safety of the plant, after which the 

transition is considered complete. According to NRC documents and 

officials, the agency expects the approval process for each plant to take 

about 2 years after the plant submits its request for a license amendment.

NRC’s change to a risk-informed approach to fire safety is part of a larger 

NRC effort to move toward accepting or adopting a risk-informed 

approach to nuclear safety in general. Examples are as follows.

• In 1995, NRC issued a policy statement encouraging the increased 

use of PRA in all regulatory matters to the extent supported by the 

state of the art in PRA methods and data and in a manner that 

NRC’s Adoption of a RiskInformed Approach
 

Page 10 GAO-13-8 Nuclear Plant Fire Safety

complemented NRC’s existing deterministic approach and supported 

NRC’s defense-in-depth philosophy.15

• In 2007, NRC issued regulations requiring applicants for combined 

licenses for new nuclear power reactors to submit a description and 

the results of a plant-specific PRA to NRC as part of their 

applications.16 NRC also began requiring recipients of combined 

licenses to develop, maintain, and periodically upgrade a plantspecific PRA. Among other things, NRC required the PRA to cover 

initiating events––that is, events that can lead to a reactor accident—

for which there are NRC-endorsed consensus standards for PRA.17

• In 2011, NRC commissioned a risk management task force to develop 

a strategic vision and options for adopting a more comprehensive riskinformed, performance-based regulatory approach. In its April 2012 

report, the task force identified goals and objectives that could be the 

framework for NRC regulatory activities 10 to 15 years in the future 

and addressed changes that would be needed to ensure that the 

framework is implemented.18 The task force reported, “NRC has 

recognized that purely deterministic and prescriptive approaches can 

limit the flexibility of both the regulated industries and the NRC to 

respond to lessons learned from operating experience and support 

the adoption of improved designs or processes.” The task force went 

on to recommend, among other things, “the goal to adopt riskinformed and performance-based approaches, where practical, should 

continue and should be incorporated into the revised regulatory 

framework.” 

 

15NRC, Use of Probabilistic Risk Assessment Methods in Nuclear Regulatory Activities;

Final Policy Statement, 60 Fed. Reg. 42,622 (Aug. 16, 1995). 

16 10 C.F.R. § 52.79(a)(46). In 1989, NRC promulgated regulations that allowed electric 

power companies to obtain a single license to build and operate a new reactor. This 

“combined license” is NRC’s response to the nuclear industry’s concerns about the length 

and complexity of NRC’s former two-step process of issuing a construction permit followed 

by an operating license. 

1710 C.F.R. § 50.71(h).

18NRC, NUREG 2150, A Proposed Risk Management Regulatory Framework

(Washington, D.C.: April 2012).
 

Page 11 GAO-13-8 Nuclear Plant Fire Safety

According to NRC documents, the 65 commercial nuclear power plants 

operating in the United States house 104 reactors that incorporate 80 

different designs. Furthermore, operators for 47 of these reactors, located 

at 29 plants, plan to or are in the process of transitioning to the riskinformed approach to fire safety. NRC has adopted a staggered schedule 

for such plants to submit license amendment requests seeking approval 

to transition to the risk-informed approach. This schedule anticipates that 

the agency will receive amendment requests from all of the plants by 

2014 and will decide on all of the requests by 2016. (Appendix III contains 

a list of transitioning plants and the dates they are scheduled to submit 

their license amendment requests to NRC.) According to NRC officials, 

the agency has implemented a discretionary enforcement policy under 

which inspection findings related to the transition will not automatically 

result in violations or penalties. The period of enforcement discretion is 

tied to each plant’s committed date for submitting its license amendment 

request and, according to NRC documents, provides incentive for plants 

to adhere to their transition schedule. Plants that elect not to complete the 

transition process must then seek exemptions or deviations or conduct 

the modifications necessary to comply with the deterministic approach.

To assist the transition process, operators at two plants—including a plant 

with three reactors in South Carolina and a plant with one reactor in North 

Carolina—participated in a pilot program for the risk-informed approach.

These plants began the transition in August 2005 and, by December 

2010, both plants had completed it. In 2011, NRC issued a report on 

lessons learned from the pilot experience for other plant operators 

interested in making the transition.19

 

19NRC, Lessons-Learned from Pilot Plant Transition to a Risk-Informed, PerformanceBased Fire Protection Licensing Basis, SECY-11-0068 (Washington, D.C.: May 2011).

Figure 3 shows the location of the 65 

power plants and identifies those with nuclear reactors that will transition 

to the risk-informed approach and those that remain under the

deterministic approach.

Status of Industry’s 

Adoption of the RiskInformed Fire Safety 

Approach 
 

Page 12 GAO-13-8 Nuclear Plant Fire Safety

Figure 3: Nuclear Power Plants with Reactors Transitioning to the Risk-Informed Approach or Remaining under the 

Deterministic Approach

Note: The 65 operating commercial nuclear power plants are located in 31 states. Some 

plants house multiple nuclear reactors.

NRC, in conjunction with plant operators, has made progress in resolving 

the three long-standing fire safety issues raised in our 2008 report at 

nuclear power plants remaining under the deterministic approach and 

those transitioning to the risk-informed approach. NRC implemented one 

of our three recommendations and took actions to resolve issues we had 

identified in making the other two recommendations but did not 

specifically implement these recommendations.

NRC Has Taken Steps 

to Resolve Longstanding Fire Safety 

Issues 
 

Page 13 GAO-13-8 Nuclear Plant Fire Safety

For the plants remaining under the deterministic approach, NRC has 

done the following in response to our 2008 recommendations:

• We recommended that NRC commit to a specific date for developing 

guidelines that reactors should meet to prevent multiple spurious 

operations. In November 2009, NRC issued a document in which it 

endorsed industry guidance for methodologies that operators might 

use to mitigate multiple spurious operations that could occur because 

of a fire. 20 NRC also set a November 2012 deadline for power plant 

operators to implement this guidance. Furthermore, as part of this 

mitigation effort, NRC required corrective actions at the 36 plants that 

have a total of 57 reactors remaining under deterministic regulations 

(hereafter referred to as nontransitioning plants).21

 

20NRC, Regulatory Guide 1.189, Fire Protection for Nuclear Power Plants, Revision 2 

(Washington, D.C.: October 2009). According to NRC officials, power plants that are 

transitioning, or planning to transition to, the risk-informed approach are currently not 

subject to this November 2012 deadline. 

Information 

gathered by industry, as well as statements to us by selected plant 

operators, indicate that most operators expect to implement the 

guidance by NRC’s deadline. According to a January 2012 industry 

survey of operators at plants housing 46 of the 57 nontransitioning 

reactors, seven of the responding operators reported that they did not 

expect to mitigate the effects of multiple spurious operations by the 

deadline; the plants where these operators work at were not identified.

We subsequently interviewed operators at 6 nontransitioning plants, 

and operators at 4 of these plants told us they expect to resolve 

issues associated with multiple spurious operations by NRC’s 

deadline. Operators at the fifth plant told us that an unexpected 

maintenance period requiring the plant to go off-line pushed back their 

mitigation of multiple spurious operations until its next maintenance 

period, which will occur after November 2012; operators at the sixth 

plant told us that their efforts to resolve other safety-related issues 

may delay their mitigation of multiple spurious operations until 2014. 

In August 2012, NRC officials told us that they may issue a generic 

letter requesting information from plant operators regarding the 

specific actions taken to mitigate multiple spurious operations 

because, under current guidance, operators are not required to 

provide such information unless requested during NRC plant 

21This number includes the sole plant that has one transitioning reactor and another 

remaining under the deterministic approach.
 

Page 14 GAO-13-8 Nuclear Plant Fire Safety

inspections.22

• NRC did not implement our recommendation that it analyze the 

effectiveness of existing fire wraps and undertake efforts to ensure 

that fire endurance tests have been conducted to qualify fire wraps as 

approved fire barriers but, according to agency documents, NRC 

addressed the concerns about fire wraps that we had raised. In an 

April 2009 letter to Congress on its actions related to our 

recommendations, NRC reported that nontransitioning plants had 

resolved this issue by taking some of the following actions: obtaining 

amendments to their license from NRC, receiving approved 

exemptions and deviations from deterministic requirements, or 

completing plant modifications to achieve compliance. Furthermore, in 

May 2010, NRC reported on compensation strategies used at plants 

to resolve fire wrap issues. NRC reported that plant operators’ efforts 

included removing deficient fire wrap, installing alternate fire wrap 

materials, and modifying areas where the wrap had been located to 

reduce fire risk.

According to these officials, NRC plans to capture 

information on the methodologies plants are using to mitigate multiple 

spurious operations, including any instances in which plants are using 

methodologies not endorsed in NRC’s guidance document. The NRC 

officials told us that the information request must go through NRC’s 

review process and public comment period, and that they did not 

expect that it would be released until November 2013 at the earliest. 

These officials stated that the information request could result in the 

need for additional work by licensees to fully mitigate multiple 

spurious operations.

23

 

22According to NRC, generic letters request that addressees (1) perform analyses or 

submit descriptions of proposed corrective actions regarding matters of safety, 

safeguards, or the environment and submit in writing that they have completed the 

requests with or without prior NRC approval of the action; (2) submit technical information

that NRC needs to perform its functions; or (3) submit proposed changes to technical 

specifications. By a generic letter, the NRC may also provide the addressees (1) staff 

technical or policy positions not previously communicated or broadly understood or (2) 

solicit participation in voluntary pilot programs.

Based on information provided by plant operators, 

NRC’s report concluded that there is reasonable assurance that the 

fire wraps currently used in nuclear power plants to provide protection 

for the safe shutdown of a power plant adequately protect public 

health and safety. Operators from four of the six nontransitioning 

23NRC, NUREG-1924, “Electric Raceway Fire Barrier Systems in U.S. Nuclear Power 

Plants” (Washington, D.C.: May 2010). 
 

Page 15 GAO-13-8 Nuclear Plant Fire Safety

plants we interviewed told us that they have deficient fire wrap in their 

plants but have resolved the associated safety issues through 

modifications approved by NRC or by obtaining exemptions from 

deterministic requirements. According to these plant operators, they 

have done so by demonstrating to NRC that other safety features 

compensate for the wraps, such as by installing upgrades to the 

wraps to meet deterministic requirements,24 or by conducting 

additional testing to demonstrate that the wraps are adequate as 

configured in the plants.

• NRC did not implement our recommendation that it address safety 

concerns related to extended use of interim compensatory 

measures25 but, in April 2009, the agency reported that it had 

committed its staff to resolving the issues that underlie the need for 

compensatory measures and developing metrics to gauge the 

progress of this effort. Beginning in 2009, NRC and the Electric Power 

Research Institute gathered data from nontransitioning plants on the 

use of “long-term compensatory measures”—measures that have 

been in place for longer than 18 months.26

 

24Under the deterministic approach, fire wraps must meet requirements to act as barriers 

to fire for 1 or 3 hours, depending on whether they are located in an area with fire 

detection and suppression devices.

NRC reported that the total 

number of areas within plants where long-term compensatory 

measures are used increased from June 2011 through December 

2011. NRC officials stated their belief that the current use of extended 

interim compensatory measures is associated with plant operator 

efforts to mitigate multiple spurious operations, but that they had not 

conducted an analysis to confirm this. Operators of five of the six 

nontransitioning plants we contacted told us that they had 

implemented interim compensatory measures while they work to 

mitigate multiple spurious operations. NRC officials told us in April 

25Specifically, we recommended that NRC define how long an interim compensatory 

measure can be used and identify the interim compensatory measures in place at nuclear 

units that exceed that threshold; assess the safety significance of such extended 

compensatory measures and define how long a safety-significant interim compensatory 

measure can be used before NRC requires the unit operator to make the necessary 

repairs or replacements or request an exemption or deviation from its fire safety 

requirements and develop a plan and deadlines for units to resolve those compensatory 

measures.

26The Electrical Power Research Institute is a nonprofit company that performs research 

and development in the electricity sector.
 

Page 16 GAO-13-8 Nuclear Plant Fire Safety

2012 that they expected that the number of long-term compensatory 

measures would decline following NRC’s deadline for mitigating 

multiple spurious operations by November 2012. However, NRC 

officials informed us in August 2012 that they were no longer certain 

that the number of long-term interim compensatory measures would 

decline as expected. According to these officials, the agency’s 

planned information request related to multiple spurious operations 

could potentially uncover issues that would require operators to 

perform additional work to mitigate spurious operations. If this occurs, 

the NRC officials told us, operators may need to use additional 

extended compensatory measures at nuclear power plants as they 

work to finally mitigate these issues after the information request is 

released as planned in November 2013.

For the plants transitioning to the risk-informed approach to fire safety, 

NRC officials and plant operators told us that they are continuing to

resolve the fire safety issues through modifications and analyses required 

to comply with the risk-informed approach. Following are examples.

• At one of the transitioning plants we visited, operators showed us a 

new control facility that is being developed to shut down the plant’s 

reactors from a separate building if a fire affects the primary shutdown 

circuits. Such a capability allows the plant to mitigate multiple spurious 

operations at a reactor.

• At that same transitioning plant, operators told us that the 

modifications and their use of PRA will eliminate their use of long-term 

compensatory measures, which predominately consisted of fire 

watches.

• At a plant we visited that had completed the transition, operators 

stated that they had significant amounts of degraded fire wrap but had 

made upgrades to areas where the fire wrap was located, including 

adding additional fire detection devices. Figure 4 shows an example 

of a fire detection device—called an incipient fire detector alarm—

installed at this plant in an area with degraded fire wrap to comply with 

the risk-informed approach. According to industry documents, the 

device detects combustion particles that overheating electrical cables 

produce before any smoke, flames, or heat. An operator at this plant 

told us that the PRA and other analysis performed as part of the 

transition had demonstrated that the wrap, in conjunction with 

upgrades, provide sufficient protection.
 

Page 17 GAO-13-8 Nuclear Plant Fire Safety

Figure 4: Incipient Fire Detection Device

The risk-informed regulatory approach to fire safety offers benefits over 

the deterministic approach, according to NRC documents we reviewed, 

and NRC officials, consultants and experts, plant operators, and industry 

representatives we spoke with, but NRC made the adoption of the riskinformed approach voluntary instead of mandatory because it considers 

plants that meet deterministic requirements to be safe. NRC officials 

stated that plant operators will have greater knowledge of plant risk and 

simpler licensing conditions under the risk-informed approach, and some 

consultants, experts, and power plant operators we interviewed stated to 

us that the approach improves plant safety. NRC ultimately elected to 

make the transition voluntary because of uncertainty over whether agency 

Benefits Cited in the 

Risk-Informed Fire 

Safety Approach, but 

NRC Considers Plants 

That Meet the 

Deterministic 

Approach to Be Safe
 

Page 18 GAO-13-8 Nuclear Plant Fire Safety

staff could make the required determination regarding the approach’s 

protection of health and safety to impose new requirements. NRC 

considers plants that meet deterministic requirements to be safe, 

including plants that do so through approved exemptions and deviations.

NRC documents and agency officials identified two major benefits of 

transitioning to the risk-informed approach. First, according to NRC 

officials, the modifications and risk assessments that plant operators 

perform as part of the transition process will help them identify and devote 

resources to activities that quantifiably reduce risk while allowing them 

greater flexibility in areas that do not significantly affect risk. For example, 

in its April 2012 risk management task force report, NRC stated that the 

risk-informed approach includes performance-based methods for 

evaluating plant configurations that would not meet the deterministic 

requirements, and that these methods allow engineering analyses to 

demonstrate that changes in overall plant risk that result from these plant 

configurations are acceptably small and that fire protection defense-indepth is maintained.27

 

27NRC, A Proposed Risk Management Regulatory Framework (April 2012).

To illustrate the difference between the riskinformed and deterministic approaches, NRC officials told us that, in 

2008, operators of a nontransitioning plant notified NRC that they had 

found 17-1⁄2 feet of separation between safety systems in a single area, 

rather than at least 20 feet as required by deterministic regulations. The 

plant had to submit an exemption request—which NRC approved 8 

months later—for what NRC officials characterized as a possibly minor or 

nonexistent safety issue. These officials told us that obtaining a single 

exemption—which could include engineering assessments or other work 

to demonstrate safety—could cost a plant tens of thousands of dollars. 

According to NRC documents, if the agency does not approve an 

exemption, a plant could be required to make safety-related modifications 

that are more expensive than obtaining an exemption but that do not 

quantifiably reduce risk. Operators from all six of the transitioning plants 

we contacted said they expected that the risk-informed approach would 

allow them to avoid making expensive modifications or seeking 

exemptions to comply with deterministic guidelines. According to NRC 

guidance and other information provided to us by NRC officials, the 

approach would also allow plant operators to have the flexibility to change 

aspects of their approved fire protection programs for reasons other than 

NRC Officials, Plant 

Operators, and 

Consultants and Experts 

Cited Various Benefits of 

the Risk-Informed 

Approach 
 

Page 19 GAO-13-8 Nuclear Plant Fire Safety

fire safety concerns—such as administrative controls, maintenance 

procedures, and physical plant modifications if they wished to do so—

without prior NRC review and approval if those modifications would not 

increase risk beyond a certain threshold.28

Second, according to NRC officials, under the risk-informed approach, 

plant operators can obtain licensing amendments that correspond to a 

single fire safety standard issued by NFPA, rather than be subject to the 

dozens of guidance documents, communications, and regulatory issue 

summaries that NRC has issued under the deterministic approach. NRC 

officials— including regional inspectors responsible for conducting fire 

safety inspections—told us they expect that simplified licensing 

requirements will enable plants to more easily demonstrate compliance 

and allow NRC inspectors to focus on technical issues significant to risk 

rather than on reading and interpreting complex licensing documents 

before conducting plant inspections. Operators from two of the six 

transitioning plants we contacted cited the prospect of clarifying or 

simplifying their license requirements as a major factor in their decision to 

adopt the risk-informed approach. For example, under this approach, 

operators at one plant expected to resolve long-standing issues dating 

from the 1980s, including differences in interpretation by the plant 

operator and NRC on how to implement deterministic requirements.

An NRC official told us that he 

was not aware of any operator of a plant meeting deterministic rules 

making the changes listed above for any reason.

An NRC webpage updated in March 2012 states that the adoption of the 

risk-informed approach “can absolutely improve an already safe operating 

environment... [and] fire risk analysis and fire science has evolved in the 

last two decades, and we now know how to make already safe plants 

safer.” The webpage also notes that early fire protection regulations were 

developed without the benefit of quantitative estimates of risk and before 

recent advances in performance-based methods such as fire modeling.

 

28NRC, Regulatory Guide 1.205: Risk-informed, Performance-based Fire Protection for 

Existing Light-Water Nuclear Power Plants (Washington, D.C.: December 2009). 

Specifically, prior NRC review and approval is not required for individual changes that 

result in a risk increase less than 1×10-7/year (yr) for CDF [core damage frequency] and 

less than 1×10‐8

/ yr for LERF [large early release frequency]. The proposed change must 

also be consistent with the defense-in-depth philosophy and must maintain sufficient 

safety margins. The change may be implemented following completion of the plant change 

evaluation.
 

Page 20 GAO-13-8 Nuclear Plant Fire Safety

Operators from the six transitioning plants and five of the nine consultants 

and experts we contacted said that they believed that transitioning plants 

will be safer than they were under the deterministic approach. Operators 

at the six transitioning plants said that the transition has improved plant 

safety because of the extensive fire safety analyses or modifications 

required during the transition process. For example, operators at one 

plant stated that they had added fire detection capabilities and that 

through safety analysis were able to determine that actions that operators 

were required to do manually in 70 areas throughout the plant to ensure 

safe shutdown under the deterministic approach were not needed. At the 

time of our review, the plant operators had yet to submit their license 

amendment request to NRC, and the agency had not formally evaluated 

the plant’s safety analysis.

NRC officials told us that the agency considers plants that meet 

deterministic requirements to be safe and, therefore, it decided not to 

require these plants to transition to the risk-informed approach. 

Furthermore, as we previously noted, under the deterministic approach 

there has not been a fire at a U.S. plant that has prevented a plant’s 

reactor from safely shutting down. Also, in the late 1990s, NRC 

conducted an analysis of selected plants and determined that the 

cumulative effects of multiple exemptions at plants under the deterministic 

approach did not pose a significant risk.29

Before deciding to make the risk-informed approach voluntary, NRC’s 

commissioners and staff considered two other options. Specifically, as 

documented in NRC’s 1998 policy statement, 30

 

29Specifically, NRC analyzed the risk assessments from 13 of the 103 reactors then in 

operation and found that only 5 of the 169 exemptions granted to these reactors were 

potentially risk-significant. NRC reported that it could not project its findings to the 90 other 

reactors, although NRC staff stated that the risk significance of the combined exemptions 

would be small because the estimated accident frequency at those reactors were lower 

than for the reactors that had been examined. See GAO, Fire Protection: Barriers to 

Effective Implementation of NRC’s Safety Oversight Process, 

NRC considered whether 

to replace the deterministic regulation with the new risk-informed 

GAO/RCED-00-39 

(Washington, D.C.: Apr. 19, 2000). 

30NRC, Development of a Risk-Informed, Performance-Based Regulation for Fire 

Protection at Nuclear Power Plants, SECY-98-058 (Washington, D.C.: March 1998). This 

document outlines three options that NRC staff considered, with industry input, related to 

adopting a risk-informed approach. 

NRC Made the RiskInformed Approach 

Voluntary Because It 

Considers Plants Meeting 

Deterministic Regulations 

to Be Safe
 

Page 21 GAO-13-8 Nuclear Plant Fire Safety

regulation or to maintain the existing deterministic framework without 

adopting risk-informed regulation. According to the policy statement, NRC 

staff recommended to allow plant operators to either voluntarily adopt the 

risk-informed approach or remain under the deterministic approach 

because it was unclear at that time whether NRC staff would be able to 

determine if the risk-informed approach improved safety over the 

deterministic approach. Such a determination would be needed for NRC 

to comply with its “backfit rule.” Under this rule, NRC is generally 

prohibited from imposing new regulatory requirements on plants unless it 

determines that the requirements (1) are necessary to provide adequate 

protection to the health and safety of the public; (2) are necessary to bring 

a facility into compliance with a license or the agency’s rules or orders, or 

into conformance with plant operators’ written commitments; or (3) would 

substantially increase protection of public health and safety and the 

implementation costs would be justified in view of the increased 

protection.31 The NRC commissioners subsequently directed the staff to 

proceed with rulemaking to make adoption of the risk-informed approach 

voluntary. Similarly, in 1998, NRC staff recommended that the 

implementation of revised regulations pertaining to a wide range of 

reactor operations should be voluntary.32

As we reported in April 2012,

At that time, the staff noted that 

it would be difficult to make the backfit determination needed to require 

mandatory implementation and further stated that doing so could create 

the impression that plants operating under the current regulations were 

less safe. Ultimately, the NRC commissioners determined that 

compliance would be voluntary.

33

 

3110 C.F.R. § 50.109(a)(3). Backfit is defined in 10 C.F.R. § 50.109(a)(1) as “the 

modification of or addition to systems, structures, components, or design of a facility; or 

the design approval or manufacturing license for a facility; or the procedures or 

organization required to design, construct or operate a facility; any of which may result 

from a new or amended provision in the Commission’s regulations or the imposition of a 

regulatory staff position interpreting the Commission’s regulations that is either new or 

different from a previously applicable staff position.” 

NRC officials told us that it generally takes 

several years to conduct and document the regulatory analyses needed 

32We reported on this decision in 1999. See GAO, Nuclear Regulation: Strategy Needed 

to Regulate Safety Using Information on Risk, GAO/RCED-99-95 (Washington, D.C.: Mar. 

19, 1999). 

33GAO, Nuclear Regulatory Commission: Natural Hazard Assessments Could Be More 

Risk-Informed, GAO-12-465 (Washington, D.C.: Apr. 26, 2012).
 

Page 22 GAO-13-8 Nuclear Plant Fire Safety

to determine whether a new requirement should be implemented. 

Similarly, NRC officials we interviewed stated that conducting a backfit 

analysis for fire safety approaches requires extensive staff resources. 

These officials told us that plants that meet the deterministic 

requirements—including those that do so through approved exemptions 

or deviations—are considered by definition to be safe in that they provide 

a reasonable assurance of adequate protection. Therefore, the agency 

does not plan to consider further the need for a mandatory adoption of the 

risk-informed approach.

NRC documents we reviewed and some of the plant operators, industry 

representatives, consultants and experts we spoke to identified three 

primary challenges that may affect plants’ ability to transition to the riskinformed approach by 2014, when NRC expects to have received 

requests for license amendments from all of the plants that have currently 

committed to make the transition. These challenges may also limit the 

number of plants that ultimately transition to the risk-informed approach 

beyond those that have already committed to doing so.

First, transition costs have been higher than expected. Operators from 7 

of the 12 plants we contacted told us that initial estimates for costs and 

resources for transition activities were relatively low (from several 

hundred thousand dollars to a few million dollars for each plant), and 

these estimates were based on projections that the activities could be 

conducted relatively easily. As information from the pilot program became

available, however, cost estimates began to rise, according to plant 

operators we spoke with. For example, operators from one pilot plant told 

us that they had originally estimated transition costs of $5 to 10 million, 

but ultimately the plant spent $20 million because plant operators 

identified the need for more modifications than planned, and conducting 

the PRA was more costly than expected. Operators from all of the 

nontransitioning plants we contacted cited the cost of the transition as a 

reason why they are remaining under the deterministic approach, and five 

of the nine consultants and experts we spoke with stated that cost was a 

basis for plants not to transition to the risk-informed approach.

According to the lessons learned report prepared by NRC staff after the 

two pilot plants completed the transition,34

 

34NRC, SECY-11-0068. 

both NRC and industry 

Plants Transitioning 

to the Risk-Informed 

Approach Face Three 

Key Challenges
 

Page 23 GAO-13-8 Nuclear Plant Fire Safety

representatives underestimated the complexity of the analyses and level 

of resources needed for the pilot plants to transition to the risk-informed 

approach. NRC officials told us that none of the currently transitioning 

plants have officially informed the agency why their transition costs have 

been higher than expected, but that the officials believe that many of the 

plant operators did not know the precise location of important cables in 

their plants; thus, they had to spend substantial resources to pinpoint the 

location of the cables before conducting their PRA. NRC’s risk 

management task force characterized the transition in its 2012 report as a 

“high-cost, high-payback” endeavor. The task force also acknowledged 

the high cost of developing high-quality PRAs and implementing fire 

protection changes; nevertheless, it stated that the cost of the 

alternative—continuing with the deterministic approach or allowing plants 

to shut down—is “even more prohibitive” for the industry. Moreover, one 

plant operator—whose plant was not involved in the pilot program—

stated that the results of the pilot program confirmed his plant’s original 

decision not to commit to the transition process.

Second, it may be difficult to develop realistic PRAs, according to industry 

documents and some of the plant operators, consultants, and experts we 

interviewed. Five of the nine consultants and 5 of the 12 plant operators 

we contacted expressed concern that NRC’s guidance for fire PRAs 

produces overly conservative results. Some of these individuals said that 

the assumptions underlying the guidance suggest that damage caused by 

fire is much more likely to occur than has actually been observed in 

nuclear power plants and that overly conservative risk assessments could 

cause plant operators to misallocate the resources available to reduce 

risk of fire. According to 4 of the 12 plant operators and two of the nine 

consultants and experts who discussed this issue with us, the specific 

reason for overly conservative PRAs is that sufficient data are not 

available to develop realistic calculations supporting fire models and 

PRAs because no major fire incidents—in which a fire threatens a plant’s 

ability to safely shut down—have occurred at nuclear power plants since 

the 1975 Browns Ferry fire. These individuals stated that, in the absence 

of sufficient data, NRC and its consultants used overly conservative 

assumptions in developing NRC’s guidance for conducting PRAs. NRC 

officials and two of the consultants we spoke with agreed that some 

aspects of NRC’s guidance are conservative, but not overly so. These 

consultants stated that overly conservative risk assessments could result 

from plant operators’ incorrect application of fire modeling, rather than 

conservative guidance by NRC. NRC is scheduled to release new 

guidance for fire modeling in October 2012 that is intended to help plant 

operators identify how to apply such modeling correctly. In addition, NRC 
 

Page 24 GAO-13-8 Nuclear Plant Fire Safety

officials told us that they are working with industry to identify areas where 

NRC’s PRA guidance can be improved as more fire data become 

available from ongoing research.

Third, the number of people experienced in fire modeling and probabilistic 

risk assessment is relatively small compared with the potential need, 

according to plant operators, consultants, and experts we spoke with.

These individuals differed on the extent to which the number of experts in 

the field would affect the transition effort. The experts needed to help with 

the transition include consultants who develop risk assessments and fire 

models for transitioning power plants, peer reviewers commissioned by 

industry who review PRAs, and NRC employees or contractors who 

assist in approving license amendments. Industry representatives we 

spoke with characterized the PRA field as barely able to keep up with the 

demands of the transition, and they noted that many individuals with 

relevant expertise are nearing retirement age. In addition, we identified 

only three universities that support accredited degree programs in fire 

protection engineering in the United States.

We have reported on the challenge posed by the limited number of 

consultants for conducting PRAs as far back as 1985.35 For example, in 

June 2008, we noted that numerous NRC officials, industry 

representatives, and academic experts expressed concern about the 

limited number of personnel with the necessary skills and training to 

develop and review PRAs. More recently, in April 2012, we reported that 

experts in PRAs had said that a key challenge to the use of these 

assessments is the limited number of experts qualified to develop 

PRAs.36

 

35See GAO, Probabilistic Risk Assessment: An Emerging Aid to Nuclear Power Plant 

Safety Regulation, 

We recognize that our April 2012 report discussed PRAs for 

natural hazards and that fires in nuclear plants are not natural hazards, 

but the same pool of individuals conduct PRAs for both types of risk. One 

of the experts we consulted for our April 2012 report noted that finding 

individuals with PRA expertise has become more difficult because NRC 

and industry are conducting PRAs for natural hazards in response to the 

Fukushima Daiichi nuclear power plant disaster. For this review, 

operators at 5 of the 12 plants we interviewed expressed concern about 

GAO/RCED-85-11 (Washington, D.C.: June 19, 1985); GAO-08-747; 

and GAO-12-465. 

36GAO-12-465. 
 

Page 25 GAO-13-8 Nuclear Plant Fire Safety

the limited numbers of individuals skilled in PRA and the effect that these 

numbers may have on plant costs and PRA quality. Operators at one 

plant estimated that they had paid twice as much in contractor fees as 

originally planned. Seven of the nine consultants and experts we 

contacted acknowledged that the current demand for expertise could, in 

the short term, limit the ability of PRA or fire modeling experts to meet all 

of the needs of industry or NRC. For example, one expert observed that it 

has been very difficult to get the number of experts needed to conduct 

peer reviews of plants’ PRAs. However, six of the nine consultants and 

experts stated that enough people with expertise will ultimately be 

available to meet the modeling and review needs of both industry and 

NRC to meet the transition schedule, in part because of increased 

demand, training, and new practitioners entering the field. For its part, 

NRC has taken some steps to manage resource needs, including 

contracting with experts from the Department of Energy’s national 

laboratories and obtaining additional staff for the NRC team responsible 

for overseeing the transition. In October 2011, NRC identified the 

transition effort as a high-priority safety activity that would not be delayed 

by work related to the agency’s Fukushima response.37

We provided a draft of this report to the Chairman of the Nuclear 

Regulatory Commission for review and comment. NRC provided written 

comments on October 12, 2012, stating that it found the draft report to be 

accurate, complete, and appropriate in its handling of sensitive 

information. NRC also provided technical comments, which we 

incorporated into our report as appropriate. NRC’s comments are 

reproduced in appendix IV.

 

37NRC, Prioritization of Recommended Actions to Be Taken in Response to Fukushima 

Lessons Learned. SECY-11-0137 (Washington, D.C.: Oct. 3, 2011).

Agency Comments 

and Our Evaluation 
 

Page 26 GAO-13-8 Nuclear Plant Fire Safety

As agreed with your offices, unless you publicly announce the contents of 

this report earlier, we plan no further distribution until 30 days from the 

report date. At that time, we will send copies to the Chairman of NRC, the 

appropriate congressional committees, and other interested parties. In 

addition, the report will be available at no charge on the GAO website at 

http://www.gao.gov. 

If you or your staff members have any questions about this report, please 

contact me at (202) 512-3841 or ruscof@gao.gov. Contact points for our 

Offices of Congressional Relations and Public Affairs may be found on 

the last page of this report. Key contributors to this report are listed in 

appendix V.

Frank Rusco

Director, Natural Resources and Environment
Appendix I: Objectives, Scope, and 

Methodology

Page 27 GAO-13-8 Nuclear Plant Fire Safety

Our review provides information on: (1) the Nuclear Regulatory 

Commission’s (NRC) progress in resolving the long-standing fire safety 

issues raised in our 2008 report at plants remaining under the 

deterministic approach and at those plants transitioning to the riskinformed approach;1

For all of these objectives, we reviewed relevant literature and NRC 

documents and interviewed NRC officials, representatives from the 

nuclear power industry, consulting organizations, public interest groups, 

and others to understand NRC’s efforts to oversee fire safety at nuclear 

power plants. In addition, we summarized the results of semistructured 

interviews from a nonprobability sample of operators of 12 nuclear power 

plants—housing a total of 24 of the nation’s 104 nuclear reactors— to 

obtain information about fire protection at plants that are remaining under 

the deterministic approach, as well as those that are transitioning to the 

risk-informed approach. Six of the plants we contacted are remaining 

under the deterministic approach, and the remaining six plants plan to or 

are in the process of transitioning to a risk-informed approach. These 

plants were Arkansas Nuclear One in Arkansas, Braidwood Nuclear 

Generating Station in Illinois, Browns Ferry Nuclear Plant in Alabama, 

Catawba Nuclear Station in South Carolina, Comanche Peak Nuclear 

Power Plant in Texas, Diablo Canyon Power Plant in California, Dresden 

Generating Station in Illinois, Edwin I. Hatch Nuclear Plant in Georgia, 

Indian Point Energy Center in New York, Joseph M. Farley Nuclear Plant 

in Alabama, Nine Mile Point Nuclear Station in New York, and Wolf Creek 

Generating Station in Kansas. We selected these plants to capture a 

variety of characteristics, including whether they are transitioning to a 

risk-informed approach to fire safety, the year their operating license was 

issued, and reactor type. The information gathered from these plants 

cannot be used to make inferences about the entire population of plants, 

or the nuclear power industry as a whole, but it does allow us to make 

qualified comparisons between different groups of plants and to discuss 

issues faced by each group. We also visited two plants, housing a total of 

four reactors, that participated in a pilot program for the risk-informed 

(2) the potential benefits of transitioning to a riskinformed approach and the basis for NRC’s decision to make adoption of 

this approach voluntary; and (3) challenges, if any, in efforts to transition 

to a risk-informed approach in regulating fire safety.

 

1

GAO-08-747. 

Appendix I: Objectives, Scope, and 

Methodology 
Appendix I: Objectives, Scope, and 

Methodology

Page 28 GAO-13-8 Nuclear Plant Fire Safety

approach to fire safety. These reactors are the Oconee Nuclear Station in 

South Carolina and the Shearon Harris Nuclear Plant in North Carolina.

We also interviewed NRC officials from the Office of General Counsel, 

Office of Nuclear Regulatory Research, the Office of Nuclear Reactor 

Regulation (including the team overseeing the transition of plants to the 

risk-informed fire safety approach), as well as NRC officials in Region II 

and Region IV. We also interviewed officials from the National Institute of 

Standards and Technology regarding their development of fire models 

used at nuclear power plants and their role in providing modeling and 

experimentation expertise in NRC’s evaluation of fire models.2

To obtain information on NRC’s progress in resolving the long-standing 

fire safety issues raised in our 2008 report at plants remaining under the 

deterministic approach and at those plants transitioning to the riskinformed approach, we reviewed relevant documents obtained from NRC 

and selected plant operators related to NRC’s progress in resolving fire 

safety issues raised in our 2008 report. We reviewed NRC and industry 

guidance to plant operators on mitigating issues associated with multiple 

spurious operations at plants remaining under the deterministic approach 

to fire safety, as well as those transitioning to the deterministic approach 

to fire safety. We also reviewed NRC reports and guidance on the use of 

fire wraps at nuclear power plants and documentation on how operators 

resolved issues associated with the use of fire wraps. We reviewed joint 

NRC and industry periodic reports on the extended use of interim 

compensatory measures at nontransitioning and transitioning plants.

Furthermore, we interviewed representatives from the Nuclear Energy 

Institute, the Union of Concerned Scientists, Beyond Nuclear, and NC 

WARN to discuss their views on NRC’s oversight of fire safety at U.S. 

nuclear power plants.

To obtain information on the potential benefits of transitioning to a riskinformed approach and the basis for NRC’s decision to make adoption of 

this approach voluntary, we reviewed relevant documents obtained from 

NRC and industry on NRC’s efforts to transition to a risk-informed 

approach to regulating fire safety at 29 plants. We reviewed NRC 

regulations, standards, and guidance on risk-informed regulation, 

 

2

Fire models can help determine how the fire may grow in time and affect structures or 

systems important for the safe shutdown of a plant. Fire modeling is used in conjunction 

with PRAs in the risk-informed fire safety approach.
Appendix I: Objectives, Scope, and 

Methodology

Page 29 GAO-13-8 Nuclear Plant Fire Safety

probabilistic risk assessment (PRA), and the use of fire modeling at 

nuclear power plants. We reviewed industry guidance documents and 

policy statements on the transition. We also summarized the results of 

semistructured interviews with nuclear engineering consultants and 

academic experts with experience in PRA, fire modeling, or both. To 

identify consultants and experts to interview, we conducted a review of 

journal articles, prior GAO reports, NRC guidance documents, industry 

conference publications, and congressional and NRC hearings. We then 

solicited recommendations from NRC, the Nuclear Energy Institute, and 

public interest groups on possible interview subjects. We also asked 

consultants and experts we contacted for our initial interviews to identify 

others whom we should interview. Out of a list of 23 potential interview 

contacts, we ultimately selected a total of nine nuclear engineering 

consultants and academic experts based on (1) the relevance of their 

publications, testimony, and background to our review and (2) the extent 

to which these individuals were recommended to us by NRC, industry 

representatives, public interest groups, and their peers. Of these nine 

individuals, six nuclear engineering consultants are currently employed by 

private consulting firms, one nuclear engineering consultant is currently 

employed by a Department of Energy national laboratory, and two 

academic experts are currently employed by universities. Appendix II lists 

the experts we interviewed. 3

 

3

We attempted to select nuclear engineering consultants and academic experts who were 

affiliated with different companies or institutions if possible; however, two of the 

consultants recognized as having extensive expertise relevant to our study are employed 

by the same parent company. On another occasion, one of the nuclear engineering 

consultants we contacted included a coworker with relevant experience in the interview; 

we have identified the coworker in appendix II, but given the similarity of his views with 

that of his colleague we count both consultants as a single interview respondent.

We contacted these nuclear engineering 

consultants or academic experts by telephone and e-mail, informed them 

about the nature of our review, and requested their participation in our 

semistructured interviews. The number of individuals with the relevant 

expertise to address our questions is limited and, as a result, all of the 

individuals we interviewed are currently working or have in the past 

worked for or consulted with the nuclear industry or NRC. We conducted 

a content analysis to assess experts’ responses to a standard set of 

questions and grouped responses into overall themes. The views 

expressed by experts do not necessarily represent the views of GAO. Not 

all of the experts provided their views on all issues.
Appendix I: Objectives, Scope, and 

Methodology

Page 30 GAO-13-8 Nuclear Plant Fire Safety

To obtain information on challenges, if any, in efforts to transition to a 

risk-informed approach in regulating fire safety, we reviewed 

documentation related to NRC’s decision to make the adoption of the riskinformed approach voluntary. We reviewed NRC regulations, guidance, 

and policy documents on the deterministic and risk-informed fire safety 

approaches, as well NRC’s 2012 risk management task force report and 

other documentation related to the agency’s expected future use of risk 

management principles in the regulation of nuclear safety. We reviewed 

NRC inspection reports from plants that are remaining under the 

deterministic approach to fire safety and those that are transitioning to a 

risk-informed approach. We summarized the results of our semistructured 

interviews with the nine nuclear engineering consultants and academic 

experts we contacted regarding their views on the benefits of the 

deterministic and risk-informed approaches to fire safety. We also 

attended relevant presentations at NRC’s March 2012 Regulatory 

Information Conference, and we observed multiple NRC public meetings 

with industry concerning issues related to the risk-informed approach to 

fire safety.

We conducted this performance audit from September 2011 to October 

2012 in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 

our findings and conclusions based on our audit objectives. We believe 

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives.
Appendix II: List of Consultants and Experts 

Contacted for This Report

Page 31 GAO-13-8 Nuclear Plant Fire Safety

• Paul J. Amico, Science Applications International Corporation

• Sean Hunt, Hughes Associates, Inc.

• Francisco J. Joglar, KGRS/Hughes Associates, Inc.

• Robert Kalantari, Engineering Planning and Management, Inc.

• Mardy Kazarians, Kazarians & Associates, Inc.

• Mohammad Modarres, University of Maryland

• Frederick W. Mowrer, California Polytechnic State University

• Steven P. Nowlen, Sandia National Laboratories

• Mark Schairer, Engineering Planning and Management, Inc.

• Clarence L. Worrell, Westinghouse Electric Company, LLC

Appendix II: List of Consultants and Experts 

Contacted for This Report
Appendix III: Schedule for Plants Transitioning 

to a Risk-Informed Approach to Fire Safety

Page 32 GAO-13-8 Nuclear Plant Fire Safety

Plant Owner State 

Number of 

units

License amendment 

request submittal 

date 

Shearon Harris Duke Energy North Carolina 1 05/29/2008

Oconee

a

Duke Energy South Carolina 3 05/30/2008b

D.C. Cook

 

Indiana Michigan Power Company Michigan 2 07/01/2011

Callaway AmerenUE Missouri 1 08/29/2011

Duane Arnold NextEra Energy Iowa 1 07/29/2011

Fort Calhoun Omaha Public Power District Nebraska 1 09/29/2011

VC Summer SC Electric and Gas South Carolina 1 11/15/2011

Waterford—Unit 3 Entergy Nuclear Operations Louisiana 1 11/17/2011

Arkansas Nuclear One—Unit 2 Entergy Nuclear Operations Arkansas 1 03/27/2012

Cooper

c

Nebraska Public Power District Nebraska 1 04/25/2012

Nine Mile Point— Unit 1 Constellation Energy New York 1 06/29/2012

Turkey Point NextEra Energy Florida 2 06/30/2012

Arkansas Nuclear One—Unit 1 Entergy Nuclear Operations Arkansas 1 08/31/2012

Beaver Valley

d

First Energy Nuclear Pennsylvania 2 09/30/2012

Brunswick 

e

Duke Energy North Carolina 2 09/30/2012

Farley Southern Nuclear Operating Company Alabama 2 09/30/2012

Prairie Island Northern States Power Minnesota 2 09/30/2012

Palisades Entergy Nuclear Operations Michigan 1 12/31/2012

Browns Ferry Tennessee Valley Authority Alabama 3 03/29/2013

Ginna

f

Constellation Energy New York 1 03/29/2013

St. Lucie NextEra Energy Florida 2 03/30/2013

San Onofre Southern California Edison California 2 03/31/2013

Diablo Canyon Pacific Gas and Electric California 2 06/28/2013

Point Beach NextEra Energy Wisconsin 2 06/30/2013

Calvert Cliffs Constellation Maryland 2 09/30/2013

Catawba Duke Energy Power South Carolina 2 09/30/2013

McGuire Duke Energy Power North Carolina 2 09/30/2013

Robinson Duke Energy South Carolina 1 09/30/2013

Davis Besse First Energy Nuclear Ohio 1 07/01/2014

Crystal River 3 Duke Energy Florida 1 07/01/2014

Source: NRC.

a

Appendix III: Schedule for Plants 

Transitioning to a Risk-Informed Approach to 

Fire Safety

Shearon Harris was a pilot plant for the risk-informed approach transition. NRC approved the plant’s 

license amendment request on June 28, 2010. 
Appendix III: Schedule for Plants Transitioning 

to a Risk-Informed Approach to Fire Safety

Page 33 GAO-13-8 Nuclear Plant Fire Safety

b

Oconee was a pilot plant for the risk-informed approach transition. NRC approved the plant’s license 

amendment request on December 29, 2010. 

c

On September 7, 2012, NRC notified Arkansas Nuclear One, Unit 2 that it did not accept the 

reactor’s license amendment request, and the reactor is no longer under enforcement discretion. 

Plant operators may resubmit an amendment request at an unspecified future date.

d

Arkansas Nuclear One, Unit 1 submitted an extension request to delay submittal of its license 

amendment request to August 2013. NRC staff are currently reviewing the extension request.

e

Beaver Valley submitted an extension request to delay submittal of its license amendment request to 

December 2013. NRC staff are currently reviewing the extension request.

f

Browns Ferry originally committed to submit its License Amendment Request in March 2012 but was 

granted an extension by NRC to March 2013. 
Appendix IV: Comments from the Nuclear 

Regulatory Commission

Page 34 GAO-13-8 Nuclear Plant Fire Safety

Appendix IV: Comments from the Nuclear 

Regulatory Commission
Appendix V: GAO Contact and Staff 

Acknowledgments

Page 35 GAO-13-8 Nuclear Plant Fire Safety

Frank Rusco, (202) 512-3841, or ruscof@gao.gov

In addition to the individual named above, Kim Gianopoulos and Ernie 

Hazera, Assistant Directors; Steve Carter; and Stephanie Gaines made 

key contributions to this report. R. Scott Fletcher, Cindy Gilbert, Amanda 

Manning, Armetha Liles, Cynthia Norris, Carol Herrnstadt Shulman, 

Jeanette Soares, and Kiki Theodoropoulos provided technical assistance.

Appendix V: GAO Contact and Staff 

Acknowledgments 

GAO Contact

Staff 

Acknowledgments 

(361326)
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