POLICY ISSUE 

(Information)

March 27, 2009 SECY-09-0048

FOR: The Commissioners 

FROM: Eric J. Leeds, Director 

Office of Nuclear Reactor Regulation 

SUBJECT: FISCAL YEAR 2008 RESULTS OF THE INDUSTRY TRENDS 

PROGRAM FOR OPERATING POWER REACTORS AND STATUS OF 

THE ONGOING DEVELOPMENT OF THE PROGRAM 

PURPOSE: 

This paper informs the Commission of the results of the U.S. Nuclear Regulatory Commission 

(NRC) Industry Trends Program (ITP) for fiscal year (FY) 2008. This paper also updates the 

Commission on the status of ongoing program development. 

BACKGROUND: 

The NRC staff implemented the ITP in 2001. The NRC uses industry-level indicators to monitor 

for adverse trends. After assessing adverse trends for safety significance, the NRC responds 

as necessary to any identified safety issues, including adjusting the inspection and licensing 

programs if necessary. One important output of the ITP is the annual agency performance 

measures reported to Congress on the number of statistically significant adverse industry trends 

in safety performance. This outcome measure is part of the NRC Performance and 

Accountability Report (PAR). In addition, the NRC annually reviews the results of the ITP and 

any actions taken or planned during the Agency Action Review Meeting. The NRC reports the 

findings of this review to the Commission. This paper is the eighth annual report to the 

Commission on the ITP. 

NRC Inspection Manual Chapter (IMC) 0313, “Industry Trends Program,” contains ITP details, 

including definitions of indicators monitored and program descriptions. 

CONTACT: Armando S. Masciantonio, NRR/DIRS 

 (301) 415-1290
The Commissioners - 2 - 

DISCUSSION: 

Using the ITP, the staff monitors industry safety performance to identify and address adverse 

industry trends. The indicators are comprehensive and based on the best available data. An 

adverse trend exists if the slope of the regression line fitted to the long-term indicator data is a 

positive value. 

The ITP also uses precursor events identified by the Accident Sequence Precursor (ASP) 

program to assess industry performance. Staff analyzes the occurrence rate of precursors to 

determine if an adverse trend exists. Staff uses the ASP results as one of the agency’s 

monitored indicators. 

 

In addition to the long-term indicators, the ITP uses a statistical approach based on prediction 

limits to identify potential short-term, year-to-year emergent issues before they become 

long-term trends. 

The ITP provides a complement to the Reactor Oversight Process (ROP). The ITP monitors 

industry-level performance while the ROP provides oversight of individual plant conditions and 

events. 

PROGRAM STATUS: 

In FY 2007, the staff completed the development of the Baseline Risk Index for Initiating Events 

(BRIIE), an indicator that monitors 9 risk-significant initiating events for boiling water reactors 

and 10 events for pressurized water reactors (the additional event category is steam generator 

tube rupture). The indicator weights each initiating event according to its relative contribution to 

industry core damage frequency. The staff reported the status of BRIIE development in 

SECY-07-0063, “Fiscal Year 2006 Results of the Industry Trends Program for Operating 

Reactors and Status of the Ongoing Development of the Program,” dated April 3, 2007. In its 

staff requirements memorandum (SRM), “Briefing on Results of the Agency Action Review 

Meeting (AARM)—Reactors,” dated June 14, 2007, the Commission directed that “the staff 

should provide to the Commission for approval a paper that describes the Baseline Risk Index 

for Initiating Events and plans for its use as a new industry-wide indicator. As part of this paper, 

the staff should discuss its communication plan.” 

Staff provided the Commission paper describing the BRIIE and the related communication plan 

in SECY-07-0184, “Industry Trends Program for Operating Power Reactors—Baseline Risk 

Index for Initiating Events,” dated October 22, 2007. In this paper, the staff recommended that 

the Commission approve implementation of the BRIIE as a new performance indicator for the 

ITP. In its SRM of December 21, 2007, related to SECY-07-0184, the Commission approved 

the staff’s recommendation. However, the Commission directed the staff to develop a public 

communication strategy to explain the meaning of the BRIIE, its underlying concept, and its 

intended use before making the information publicly available and before beginning the practice 

of reporting the BRIIE results to Congress. The Commission also directed that, when making 

the BRIIE publicly available, the staff should provide supporting data where appropriate and 

update the NRC public Web site to discuss the BRIIE. 
The Commissioners - 3 - 

These initiatives were completed in May 2008. 

In SECY-08-0041, “Fiscal Year 2007 Results of the Industry Trends Program for Operating 

Power Reactors and Status of the Ongoing Development of the Program,” the staff committed to 

incorporate the BRIIE concept into NRC IMC 0313 and to formally report BRIIE results as an 

ITP indicator in this Commission paper. The staff also committed, in SECY-06-0076, “Fiscal 

Year 2005 Results of the Industry Trends Program for Operating Power Reactors and Status of 

the Ongoing Development of the Program,” to revise IMC 0313 to include a process to ensure 

revised or updated data (such as data from inspection findings and ASP results) are included, 

as appropriate, in the performance indicator for Significant Events. The agency issued the 

revision to IMC 0313 on May 29, 2008, to address both the new process and the BRIIE concept. 

The following sections provide the ITP and BRIIE results for FY 2008. 

FY 2008 LONG-TERM INDUSTRY TREND: 

Based on the ITP indicators and the ASP program results, the staff did not identify any 

statistically significant adverse trends in industry safety performance through the end of 

FY 2008. The graphs in Enclosure 1 show the long-term ITP indicator trends and the ASP 

precursor data. The ASP program considers an event with a conditional core damage 

probability (CCDP) or increase in core damage probability (ΔCDP) greater than or equal to 

1×10-6 to be a precursor. 

Figure 14 of Enclosure 1 is a graph depicting the occurrence rate of total precursors by fiscal 

year. It shows the occurrence rate for all precursors by fiscal year during the period FY 1988 - 

FY 2007. The staff evaluated precursor data from FY 2001 to FY 2007 to identify statistically 

significant adverse trends. A review of the data reveals (1) a statistically significant decreasing 

trend for all precursors during this 7-year period, and (2) a statistically significant decreasing 

trend for precursors with a CCDP or ΔCDP greater than or equal to 1×10-4 during this same 

period. The staff chose FY 2001 as the starting point for trend analyses to provide a data period 

with a consistent ASP program scope and to align it with the first full year of the ROP. ASP 

program changes in FY 2001 (e.g., inclusion of Significance Determination Process findings and 

external initiated events) significantly increased the number of precursors identified compared to 

those identified in previous years. The data period for trending analyses ends in FY 2007 (the 

last full year of completed ASP analyses) but will become a rolling 10-year period in the future. 

The ASP program also provides the basis for the safety performance measure of zero “number 

of significant accident sequence precursors of a nuclear reactor accident.” This is one measure 

associated with the safety goal established in the NRC’s Strategic Plan. A significant precursor 

is an event that has a probability of at least 1 in 1,000 (greater than or equal to 1×10-3) of 

leading to a reactor accident. A review of the data reveals that the mean occurrence rate of 

significant precursors does not exhibit a statistically significant trend for the period 

FY 2001-FY 2008. The staff identified no significant precursors in FY 2008. 

The staff reported the results of the ASP program to the Commission in SECY-08-0145, “Status 

of the Accident Sequence Precursor Program and the Development of Standardized Plant 

Analysis Risk Models,” dated October 1, 2008.
The Commissioners - 4 - 

FY 2008 SHORT-TERM INDUSTRY PERFORMANCE: 

In addition to the long-term trend monitoring, the staff uses a statistical approach based on 

prediction limits to identify potential short-term, year-to-year emergent issues before they 

become long-term trends. Enclosure 2 shows the short-term results and the prediction limits for 

each of the ITP indicators. None of the indicators exceeded its prediction limit in FY 2008. 

Short-term FY 2008 data did not reveal any issues that warranted additional analysis or 

significant adjustments to the nuclear reactor safety inspection or licensing programs. 

FY 2008 BRIIE RESULTS: 

The BRIIE concept provides a two-level approach to industry performance monitoring: 

(1) it tracks several types of events that could potentially start (“initiate”) a challenge to a plant’s 

safety systems; (2) it assigns a value to each initiating event according to its relative importance 

to the plant’s overall risk of damage to the reactor core; and (3) it calculates an overall indicator 

of industry safety performance. 

The first level (referred to as Tier 1 performance monitoring) tracks and counts the number of 

times the initiating events that have an impact on plant safety occur in nuclear power plants 

during the year. Nine initiating event categories are monitored for boiling water reactors; ten for 

pressurized water reactors. The number of times that each event occurs is compared with a 

predetermined number of occurrences for that event. If the predetermined number is exceeded, 

one can infer possible degradation of industry safety performance. This annual tracking allows 

the NRC to intervene and engage the nuclear industry before any long-term adverse trends in 

performance emerge. 

 

The second level (referred to as Tier 2 performance monitoring) addresses the risk to plant 

safety and core damage that each of the initiating events contributes. Each of the events is 

assigned an importance value, a ranking according to its relative contribution to overall risk to 

plant safety. The greater the contribution of the event to overall risk, the higher the importance 

value that is assigned to the event. Using statistical methods, the importance values are 

combined with the number of times the events occur during the year to calculate a number that 

indicates how much the overall industry risk of damage to the reactor core has changed from a 

baseline value. A report is made as part of the NRC PAR if the BRIIE combined industry value 

reaches or exceeds a threshold value of 1×10-5 per reactor critical year along with actions that 

have already been taken or are planned in response. 

Enclosure 3 provides the Tier 1 and Tier 2 BRIIE results. None of the initiating events tracked in 

Tier 1 exceeded its prediction limit in FY 2008. As shown in Enclosure 3, Figure 15, BRIIE Tier 

2 (Change in CDF), the BRIIE combined industry value in FY 2008 (-5.2×10-6 per reactor critical 

year) is well below the established threshold of 1×10-5 per reactor critical year. 

RESOURCES: 

NRR staff estimates resource needs of approximately 0.5 Full-Time Equivalent (FTE) staff and 

$425,000 for ongoing ITP implementation in each of FY 2009 and FY 2010. The resources are 
The Commissioners - 5 - 

included in the FY 2009 budget and FY 2010 budget request as part of the Reactor Oversight 

Process (ROP) in Subprogram: Reactor Oversight; Planned Activity: Reactor Performance 

Assessment. The Office of Nuclear Regulatory Research (RES) provides indirect support to the 

ITP in the areas of operating experience data and models developed and budgeted under other 

RES programs such as the simplified plant analysis risk program, the ASP program, and the 

reactor operating experience data collection and analysis program. The ITP uses the results of 

RES work in the ASP program to assess industry performance although the RES work is funded 

and performed completely separate from the ITP. RES has included 5.3 FTE and $487,000 in 

both the FY 2009 budget and FY 2010 budget request for their work. The resources budgeted 

in the Office of Nuclear Reactor Regulation and RES are adequate for ongoing ITP 

implementation. Resources required in future years beyond FY 2010 would be addressed 

during the Planning, Budgeting, and Performance Management (PBPM) process of the 

respective year. 

COORDINATION: 

The Office of the Chief Financial Officer has reviewed this paper and concurs. The Office of the 

General Counsel has reviewed this paper and has no legal objection. 

 /RA/

 Eric J. Leeds, Director 

Office of Nuclear Reactor Regulation 

Enclosures: 

1. Fiscal Year 2008 Long-Term Industry 

 Trends Results 

2. Fiscal Year 2008 Short-Term Industry 

 Performance 

3. Fiscal Year 2008 BRIIE Results 
The Commissioners - 5 - 

 

included in the FY 2009 budget and FY 2010 budget request as part of the Reactor Oversight 

Process (ROP) in Subprogram: Reactor Oversight; Planned Activity: Reactor Performance 

Assessment. The Office of Nuclear Regulatory Research (RES) provides indirect support to the 

ITP in the areas of operating experience data and models developed and budgeted under other 

RES programs such as the simplified plant analysis risk program, the ASP program, and the 

reactor operating experience data collection and analysis program. The ITP uses the results of 

RES work in the ASP program to assess industry performance although the RES work is funded 

and performed completely separate from the ITP. RES has included 5.3 FTE and $487,000 in 

both the FY 2009 budget and FY 2010 budget request for their work. The resources budgeted 

in the Office of Nuclear Reactor Regulation and RES are adequate for ongoing ITP 

implementation. Resources required in future years beyond FY 2010 would be addressed 

during the Planning, Budgeting, and Performance Management (PBPM) process of the 

respective year. 

COORDINATION: 

The Office of the Chief Financial Officer has reviewed this paper and concurs. The Office of the 

General Counsel has reviewed this paper and has no legal objection. 

 

/RA/ 

 Eric J. Leeds, Director 

Office of Nuclear Reactor Regulation 

Enclosures: 

1. Fiscal Year 2008 Long-Term Industry 

 Trends Results 

2. Fiscal Year 2008 Short-Term Industry 

 Performance 

3. Fiscal Year 2008 BRIIE Results 

WITS200100034/EDATS: SECY-2008-0223 

ADAMS Accession Number: ML090420101 *Concurred by e-mail 

OFFICE IPAB/DIRS IPAB/DIRS Tech Editor* IOEB/DIRS* PMDA/NRR* 

NAME AMasciantonio 

(RFranvoich for) RFranovich CHsu MJRoss-Lee TDietz 

DATE 02/19/09 02/19/09 02/10/09 02/13/09 02/23/09 

OFFICE DIRS/NRR OCFO* OGC (NLO)* RES NRR 

NAME FBrown TPulliam EWilliamson BSheron 

(JLyons for) ELeeds 

DATE 03/09/09 03/11/09 02/26/09 02/25/09 03/27/09 

OFFICIAL RECORD COPY
 

 Enclosure 1 

FISCAL YEAR 2008 LONG-TERM INDUSTRY TRENDS RESULTS 

No statistically significant adverse trends were observed in the Industry Trends Program 

performance indicator data from the most recent 10 years (fiscal year (FY) 1999 to FY 2008) as 

indicated by the following graphs. 

Automatic Scrams While Critical

0.64

0.52

0.57

0.44

0.75

0.56

0.47

0.32

0.48

0.29

0.00

0.50

1.00

1.50

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Scrams per Unit

Industry Average

Industry Average Trend

Figure 1. Automatic Scrams While Critical 
2 

Safety System Actuations

0.29 0.29

0.19 0.18

0.42

0.24

0.38

0.22

0.25

0.14

0.00

0.25

0.50

0.75

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Actuations per Unit

Industry Average

Industry Average Trend

Figure 2. Safety Systems Actuations 

Significant Events

0.03

0.04

0.07

0.05

0.07

0.04

0.05

0.03

0.02 0.02

0.00

0.04

0.08

0.12

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per Unit

Industry Average

Industry Average Trend

Figure 3. Significant Events 
 

3

Safety System Failures

1.68

1.40

0.83 0.87

0.96

0.78

0.99

0.59 0.65 0.64

0

1

2

3

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Failures per Unit

Industry Average

Industry Average Trend

Figure 4. Safety System Failures 

Forced Outage Rate (%)

5.20

4.24

3.00

1.70

3.04

1.88

2.44

1.47 1.43 1.34

0

2.5

5

7.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Forced Outage Rate (%)

Industry Average

Industry Average Trend

Figure 5. Forced Outage Rate 
 

4

Equipment Forced Outages/1000 Commercial Critical Hours

0.16

0.13

0.11

0.12

0.16

0.15

0.13

0.10

0.11

0.08

0.0

0.1

0.2

0.3

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Equipment Forced Outages/

1000 Comm. Crit. Hours

Industry Average

Industry Average Trend

Figure 6. Equipment Forced Outages per 1000 Commercial Critical Hours 

Collective Radiation Exposure

128

115

123

111

125

100

117

93

110

96

0

50

100

150

200

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Average Exposure per Unit

(Person-REM)

Industry Average

Industry Average Trend

Figure 7. Collective Radiation Exposure 
 

5

Unplanned Power Changes

1.51

1.39

1.21

1.07

1.15

1.00 0.97

0.91 0.91 0.89

0.0

0.5

1.0

1.5

2.0

2.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Power Changes per 7000 Critical Hours

Industry Average

Industry Average Trend

Figure 8. Unplanned Power Changes 

Reactor Coolant System Activity

1.53

0.76

0.52 0.51

0.41 0.42 0.39

0.58

0.43 0.44

0.0

0.5

1.0

1.5

2.0

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Maximum Percentage of Technical 

Specification Limits

Industry Average

Industry Average Trend

Figure 9. Reactor Coolant System Activity 
 

6

Reactor Coolant System Leakage

5.76

7.94

5.86

5.16

4.82 4.64 4.45

4.08

4.35 4.42

0

4

8

12

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Maximum Percentage of Technical 

Specification Limits

Industry Average

Industry Average Trend

Figure 10. Reactor Coolant System Leakage 

Drill/Exercise Performance

96.57

95.94

95.44 95.28

95.73 95.64

95.85

96.07 96.15 96.29

92

94

96

98

100

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Percentage Timely and Accurate

Industry Average

Industry Average Trend

Figure 11. Drill/Exercise Performance 
 

7

ERO Drill Participation

96.34 96.30

97.10

97.74 97.87

98.20

97.96

97.58

98.34

92

94

96

98

100

2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Note: Complete Fiscal Year 1999 Data not Available

Percentage of Key Personnel

Industry Average

Industry Average Trend

Figure 12. Emergency Response Organization Drill Participation 

Alert and Notification System Reliability

98.05 98.02

98.52

98.79

98.92

99.24

99.34

99.48 99.45

99.53

97

98

99

100

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Percentage of Tests Successful

Industry Average

Industry Average Trend

Figure 13. Alert and Notification System Reliability 
 

8

Accident Sequence Precursors 

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Fiscal Year

Occurrence Rate

Historical Precursors (FYs 88-00)

FY 01-07 Precursors

Mean (FYs 2001-2007)

 Figure 14. Accident Sequence Precursors 

Total precursors—occurrence rate, by fiscal year. Data for FY 1988–FY 2000 

are shown for historical perspective. A statistically significant decreasing trend 

(p-value=0.03) is detected for the FY 2001–FY 2007 period. 
 Enclosure 2 

FISCAL YEAR 2008 SHORT-TERM INDUSTRY PERFORMANCE

The annual industry trend analysis compares the data for the most recent year with 

established short-term “prediction limits.” The prediction limits are 95th percentiles of 

predictive distributions for the data. The predictive distributions are statistical probability 

distributions that describe expected future performance. They are derived from 

performance during “baseline” periods for each performance indicator (PI). Baseline 

periods are periods for each PI during which the data can be regarded as fairly constant 

and indicative of “current” performance. Therefore, for each PI, a series of trend 

analyses was performed to identify, if possible, a baseline period in which no statistically 

significant trend exists. In the Industry Trends Program (ITP) methodology, the 

minimum baseline period is at least 4 years, ending in the year with the most recent data 

(initially fiscal year (FY) 2002). If the most recent 4-year period satisfies the criteria, then 

the most recent 5-year period is considered. Successively longer periods are selected, 

as long as the statistical models fit and the test for trends shows little evidence of a 

trend. In the current methodology, whenever a new baseline period is sought, the period 

selected is the one that shows the least evidence of a trend. The results of the 

evaluation of the FY 2008 ITP PIs, using the established prediction limits, indicate that 

no PI exceeded its associated prediction limit in FY 2008, as evidenced by graphs of 

each PI with its FY 2008 data and associated prediction limit provided in the following 

pages. 
2 

 

Safety System Actuations

0.00

0.25

0.50

0.75

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Actuations per Unit

Industry Average

Prediction Limit (0.375)

Baseline Industry Average (0.275), 1998-2005

Automatic Scrams While Critical

0.00

0.25

0.50

0.75

1.00

1.25

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Scrams per Unit

Industry Average

Prediction Limit (0.673)

Baseline Industry Average (0.533), 1997-2002

Figure 1. Automatic Scrams While Critical 

 

 

 (See endnote 1) 

Figure 2. Safety System Actuations 
3 

 

Significant Events

0.00

0.03

0.06

0.09

0.12

0.15

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per Unit

Industry Average

Prediction Limit (0.106)

Baseline Industry Average (0.0524), 2000-2004

Figure 3. Significant Events 

Safety System Failures

0.0

0.5

1.0

1.5

2.0

2.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Failures per Unit

Industry Average

Prediction Limit (1.04)

Baseline Industry Average (0.859), 2001-2004

Figure 4. Safety System Failures 
4 

 

Forced Outage Rate

0

2

4

6

8

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Forced Outage Rate (%)

Industry Average

Prediction Limit (4.28)

Baseline Industry Average (2.40), 2001-2004

Figure 5. Forced Outage Rate 

Equipment Forced Outages/1000 Commercial Critical Hours

0

0.05

0.1

0.15

0.2

0.25

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Equipment Forced Outage Rate

Industry Average

Prediction Limit (0.180)

Baseline Industry Average (0.142), 1998-2004

Figure 6. Equipment Forced Outages per 1000 Commercial Critical Hours 
5 

 

Collective Radiation Exposure

0

50

100

150

200

250

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Average Exposure per Unit (Person-REM) 

Industry Average

Prediction Limit (139)

Baseline Industry Average (119), 1999-2002

Figure 7. Collective Radiation Exposure 

Unplanned Power Changes

0.0

0.5

1.0

1.5

2.0

2.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Power Changes per 7000 Critical Hours

Industry Average

Prediction Limit (1.30)

Baseline Industry Average (1.10), 2001-2004

Figure 8. Unplanned Power Changes per 7000 Critical Hours 
6 

 

Reactor Coolant System Leakage

0

2

4

6

8

10

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Maximum Percentage of Tech. Spec. Limits

Industry Average

Prediction Limit (6.32)

Baseline Industry Average (5.14), 2000-2004

Reactor Coolant System Activity

0.0

0.5

1.0

1.5

2.0

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Maximum Percentage of Tech. Spec. Limits

Industry Average

Prediction Limit (0.646)

Baseline Industry Average (0.462), 2001-2004

Figure 9. Reactor Coolant System Activity 

 

 (See endnote 1) 

Figure 10. Reactor Coolant System Leakage 
7 

 

Drill/Exercise Performance

92

94

96

98

100

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Percentage Timely and Accurate

Industry Average

Prediction Limit (95.2)

Baseline Industry Average (95.6), 2000-2004

Figure 11. Drill/Exercise Performance 

ERO Drill Participation

94

96

98

100

2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Percentage of Key Personnel

Industry Average

Prediction Limit (97.5)

Baseline Industry Average (97.9), 2003-2007

Figure 12. Emergency Response Organization Drill Participation 
8 

 

Alert and Notification System Reliability

97

98

99

100

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Percentage of Tests Successful

Industry Average

Prediction Limit (98.3)

Baseline Industry Average (98.9), 2001-2004

Figure 13. Alert and Notification System Reliability

NOTE 1: The 2003 blackout event in the safety system actuations graph (Figure 2) and 

the 2000 Indian Point 2 steam generator tube rupture event in the reactor coolant 

system leakage graph (Figure 10) were not included in the short-term data for the 

purpose of determining prediction limits. They were excluded from the development of 

the prediction limit models because they are considered outlier events that overly 

influenced the statistical analysis of the industry-wide data. Removing these events 

resulted in less restrictive prediction limits. 
 Enclosure 3 

FISCAL YEAR 2008 BRIIE RESULTS 

The Baseline Risk Index for Initiating Events (BRIIE) addresses the Initiating Event (IE) 

Cornerstone in the U.S. Nuclear Regulatory Commission’s (NRC’s) Reactor Oversight 

Program (ROP) for monitoring boiling water reactor and pressurized water reactor 

commercial nuclear power plants (NPP). It is based on NPP performance for the 

following 10 initiators: 

 Initiator Acronym Applicable Plants 

 General transient TRAN Both plant types, separately 

 Loss of condenser heat sink LOCHS Both plant types, separately 

 Loss of main feedwater LOMFW Both plant types 

 Loss of offsite power LOOP Both plant types 

 Loss of vital AC bus LOAC Both plant types 

 Loss of vital DC bus LODC Both plant types 

 Stuck open SRV SORV Both plant types, separately 

 Loss of instrument air LOIA Both plant types, separately 

 Very small LOCA VSLOCA Both plant types 

 Steam generator tube rupture SGTR Pressurized water reactors only 

The BRIIE program, as described in NRC Inspection Manual Chapter 0313, “Industry 

Trends Program,” and in NUREG /CR-6932, “Baseline Risk Index for Initiating Events 

(BRIIE),” consists of two levels, or tiers. The first considers individual IEs and evaluates 

performance based on statistical prediction limits. This evaluation is for ongoing 

monitoring and early detection of possible industry-level deficiencies. A second tier is a 

risk-based, integrated measure, evaluated for each plant type. Since four of the 

initiators have separate data for each plant type, there are a total of fourteen Tier 1 

graphs. 

The units for the Tier 1 initiating event frequency graphs are event counts for a fiscal 

year, divided by the industry critical time for the year. The Tier 1 graphs also show the 

average frequency for an established “baseline period,” and 95 percent prediction limits 

for a future year if occurrences continue at the same rate as in the baseline period. 

The prediction limits depend on the expected number of critical years of reactor 

operation in the upcoming year as well as on the baseline occurrence rate for each 

indicator. A rate can exceed a limit by having more events than expected, or by having 

events and less critical time than expected. In recent years, U.S. nuclear power plant 

availability has been approximately 90 percent at the industry level. This figure enters 

into the calculations determining the bounds on the number of events that might be 

expected. For all of the initiators, the 2008 occurrence rates are lower than the 

associated prediction limits. 

The Tier 2, integrated index includes, for each plant type, the relative contribution of 

each initiator to the risk of core damage, based on the events that occurred in each fiscal 

year. The event frequencies are converted to core damage frequency estimates by 

multiplying by Birnbaum risk coefficients. These coefficients are industry averages of 

the contribution to core damage from each initiator as reflected in the industry 

standardized plant analysis risk (SPAR) models. 

The BRIIE Tier 2 plot, Figure 15, shows annual differences in estimated industry core 

damage frequency compared with the established baseline levels of these quantities. 

The combined industry BRIIE value in FY 2008 (-5.2×10-6 per reactor critical year) is well 

below the established threshold of 1×10-5 per reactor critical year. 
2 

PWR General Transients

0.95

0.70

0.75

0.51

1.1

0.73

0.53 0.54

0.63

0.56

0.0

0.5

1.0

1.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1998 - 2002

 Baseline industry average

 95% prediction limit for one year

 Figure 1. PWR General Transients

BWR General Transients

0.95 0.95

0.72

0.78

0.93

0.68

0.77

0.53

0.94

0.61

0.0

0.5

1.0

1.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1997 - 2002

 Baseline industry average

 95% prediction limit for one year

 Figure 2. BWR General Transients 
3 

 

PWR Loss of Condenser Heat Sink

0.050

0.097

0.13

0.048

0.081

0.11

0.080 0.079

0.048

0.016

0.00

0.05

0.10

0.15

0.20

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year

Baseline period: 1995 - 2002

 Baseline industry average

 95% prediction limit for one year

 Figure 3. PWR Loss of Condenser Heat Sink 

BWR Loss of Condenser Heat Sink

0.24

0.25

0.063

0.16

0.29

0.25

0.23

0.031

0.19

0.12

0.0

0.1

0.2

0.3

0.4

0.5

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1996 - 2002

 Baseline industry average

 95% prediction limit for one year

 Figure 4. BWR Loss of Condenser Heat Sink
4 

 

Loss of Offsite Power

0.011 0.011

0.021

0

0.13

0.053

0

0.021

0.011

0

0.00

0.05

0.10

0.15

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year

Baseline period: 1997 - 2004

 Baseline industry average

 95% prediction limit for one year

Loss of Main Feedwater

0.12

0.075

0.064

0.021

0.086 0.084 0.086

0.042

0.063

0.052

0.00

0.05

0.10

0.15

0.20

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1993 - 2002

 Baseline industry average

 95% prediction limit for one year

 Figure 5. Loss of Main Feedwater

 

 (See endnote 1) 

 Figure 6. Loss of Offsite Power 
5 

 

Loss of Vital AC Bus

0.022

0.011

0.021

0

0.011

00000

0.00

0.02

0.04

0.06

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1992 - 2002

 Baseline industry average

 95% prediction limit for one year

 Figure 7. Loss of Vital AC Bus

Loss of Vital DC Bus

0.011

000000000

0.00

0.01

0.02

0.03

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1988 - 2002

 Baseline industry average

 95% prediction limit for one year

 Figure 8. Loss of Vital DC Bus
6 

 

PWR Stuck Open SRV

0000000000

0.00

0.01

0.02

0.03

0.04

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1988 - 2002

 Baseline industry average

 95% prediction limit for one year

 Figure 9. PWR Stuck Open SRV

BWR Stuck Open SRV

0 0

0.063

0.031 0.032 0.031

0000

0.00

0.03

0.06

0.09

0.12

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1993 - 2002

 Baseline industry average

 95% prediction limit for one year

 Figure 10. BWR Stuck Open SRV
7 

 

PWR Loss of Instrument Air

0 0

0.016 0.016 0.016

0 0

0.016 0.016

0

0.00

0.02

0.04

0.06

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1997 - 2002

 Baseline industry average

 95% prediction limit for one year

Figure 11. PWR Loss of Instrument Air

BWR Loss of Instrument Air 

0000000

0.031

0 0

0.00

0.02

0.04

0.06

0.08

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1991 - 2002

 Baseline industry average

 95% prediction limit for one year

Figure 12. BWR Loss of Instrument Air
8 

 

Very Small LOCA

000000

0.011

000

0.00

0.01

0.02

0.03

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1992 - 2002

 Baseline industry average

 95% prediction limit for one year

Figure 13. Very Small LOCA 

PWR Steam Generator Tube Rupture

0

0.016

00000000

0.00

0.01

0.02

0.03

0.04

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Events per reactor critical year Baseline period: 1991 - 2002

 Baseline industry average

 95% prediction limit for one year

Figure 14. PWR Steam Generator Tube Rupture 
9 

BRIIE Tier 2 (Change in CDF)

-1.0E-05

-5.0E-06

0.0E+00

5.0E-06

1.0E-05

1.5E-05

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Fiscal Year

Delta CDF (1/rcry)

PWR BWR Industry Using Bayesian updates of annual frequencies

Industry BRIIE threshold for one year of data: 1.E-5

 Figure 15. BRIIE Tier 2 (Change in Core Damage Frequency) 

NOTE 1: The prediction limit for the Loss of Offsite Power (LOOP) graph, shown in 

Figure 6, was calculated assuming the 9 LOOP events that occurred during the 2003 

blackout event were a single event. This treatment results in a more conservative 

prediction limit.