POLICY ISSUE 

Information 

April 5, 2016 SECY-16-0044 

FOR: The Commissioners 

FROM: William M. Dean, Director 

Office of Nuclear Reactor Regulation 

SUBJECT: FISCAL YEAR 2015 RESULTS OF THE INDUSTRY TRENDS 

PROGRAM FOR OPERATING POWER REACTORS 

PURPOSE: 

The purpose of this paper is to inform the Commission of the results of the U.S. Nuclear 

Regulatory Commission’s (NRC’s) industry trends program (ITP) for fiscal year (FY) 2015. In 

summary, the staff did not identify any statistically significant adverse trends in industry safety 

performance that required generic actions. This paper does not address any new commitments 

or resource implications. 

BACKGROUND: 

The staff established the ITP in 2001 to monitor trends in licensee safety performance using 

industry-level indicators. Should the staff identify any statistically significant adverse trends, 

further analysis would be conducted to determine whether the trends are unduly influenced by a 

small number of outliers and to identify any causal factors. If the trends are not a result of 

outliers in the data, adjustments to the NRC’s inspection program may result. The NRC reviews 

the results of the ITP and any actions taken or planned as a result during the annual Agency 

Action Review Meeting. The NRC reports the findings of this review to the Commission during 

the subsequent Commission meeting. 

CONTACT: Andrew J. Waugh, NRR/DIRS 

 (301) 415-5601 

 
The Commissioners - 2 - 

NRC Inspection Manual Chapter (IMC) 0313, “Industry Trends Program,” dated January 

26, 2016 (Agencywide Documents Access and Management System (ADAMS) Accession 

No. ML15316A039), contains details of the ITP including definitions of monitored indicators and 

program descriptions. 

Using the ITP, the staff monitors industry-wide safety performance to identify and address any 

statistically significant adverse trends. A statistically significant adverse trend exists if the slope 

of the regression line fitted to the long-term indicator data has a positive value and the fit of the 

regression line is statistically relevant. 

In addition to 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 short-term prediction limits are determined from an established baseline period 

during which data can be regarded as fairly constant. 

The ITP is designed to complement the Reactor Oversight Process (ROP). Specifically, the ITP 

monitors and responds to industry-wide performance, whereas the ROP provides oversight of 

individual reactor sites commensurate with their safety performance. 

In 2008, the NRC staff established the Baseline Risk Index for Initiating Events (BRIIE) as part 

of the ITP. The BRIIE tracks several types of events that could potentially initiate a challenge to 

a plant’s safety systems. Nine initiating event categories are monitored for boiling-water 

reactors and ten for pressurized-water reactors. The number of times that each event occurs is 

compared to a predetermined number of occurrences for that event. The predetermined 

number of occurrences is calculated using information from an established baseline period. If 

the predetermined number is exceeded, the staff assesses whether there is a possible 

degradation in overall industry safety performance. This annual tracking is intended to allow the 

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

performance emerge. 

In 2016, the staff recommended elimination of the ITP in SECY-16-0009, “Recommendations 

Resulting from the Integrated Prioritization and Re-Baselining of Agency Activities.” This 

recommendation noted that while the ITP provides data that helps to validate broad industry 

performance trends, no regulatory action has ever resulted from ITP insights. In considering the 

cost of the program, staff noted that any negative trends in performance that the ITP might 

highlight could be self-revealing or identified through other means. If the Commission approves 

elimination, licensee submittal of data will not be affected, but this will be the final ITP report. 

DISCUSSION: 

Status of Changes to the ITP 

On June 13, 2013, the Commission issued a staff requirements memorandum (SRM) in 

response to the May 29, 2013, “Briefing on the Results of the Agency Action Review Meeting 

(AARM).” In this SRM the Commission directed the staff to review the ITP as follows: 

As part of the Reactor Oversight Process (ROP) Self-Assessment for calendar year (CY) 

2013, the staff should review implementation of the Industry Trends Program over its 
The Commissioners - 3 - 

history for lessons learned and inform the Commission of any program enhancements 

and/or resource reductions that may be warranted. 

After completing the review of the ITP in 2013, the staff committed in SECY-14-0042, “Fiscal 

Year 2013 Results of the Industry Trends Program for Operating Power Reactors,” to evaluate 

including new indicators measuring industry performance in ROP cornerstones that had not 

previously been measured, such as the public radiation safety cornerstone and the security 

cornerstone. The staff also committed to evaluating the possibility of supplementing or 

replacing ITP indicators with ROP performance indicators (PIs), where applicable.

In 2015, the staff completed these evaluations. The staff determined that shifting from ITP 

indicators to ROP PIs and including indicators representing all cornerstones would provide the 

following advantages: 

• A more holistic view of industry safety performance would be achieved because all 

cornerstones of the ROP would be evaluated; 

• data collection would be more efficient and the time lag of some of the ITP indicators 

would be reduced; 

• the significant resource burden (i.e., contract support) related to data collection and 

analysis would be greatly reduced; and 

• the ITP would be more understandable by using the ROP PIs because the ROP PIs are 

more commonly used and widely disseminated. 

Based on the staff’s evaluation, IMC 0313 was revised on January 26, 2016, to replace ITP 

indicators with ROP PIs. 

Development of the methods to conduct statistical analysis and to establish prediction limits for 

these new indicators is ongoing and will be completed in 2016. This paper presents both the 

results for the new indicators that have a completed statistical analysis, as well as the results for 

indicators which have recently been replaced by the IMC 0313 revision. The previous revision 

of IMC 0313, “Industry Trends Program,” dated May 29, 2008 (ADAMS Accession 

No. ML080860540), contains definitions and details on these ITP indicators that were recently 

replaced. 

This paper contains four enclosures. As with previous ITP papers, the first three enclosures 

provide the results for the review of long-term trends, short-term comparison to prediction limits, 

and the BRIIE for FY 2015. In order to provide continuity during the transition to new indicators 

for the ITP, this paper also includes a fourth attachment with results for long-term and 

short-term analysis of the ITP indicators that are being replaced and will no longer be used 

going forward. 

Results of FY 2015 Long-Term Industry Trends 

For FY 2015, the staff did not identify any statistically significant adverse trends using the 

revised indicators. The graphs in enclosure 1 show the long-term ITP indicator trends. Five 

indicators showed statistically significant improving trends. Trend lines are provided for those 
The Commissioners - 4 - 

indicators with a statistically significant trend. The staff evaluated both linear and exponential 

trend lines for each set of data and used the trend line showing the highest degree of statistical 

significance. 

Results of FY 2015 Short-Term Industry Performance 

As described above, 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 prediction limits for each of the revised indicators 

where statistical analysis is complete. None of the indicators exceeded their prediction limits in 

FY 2015. Short-term FY 2015 data did not reveal any emerging trends that warranted additional 

analysis or significant adjustments to the nuclear reactor safety inspection or licensing 

programs. 

Results of FY 2015 Baseline Risk Index for Initiating Events 

Enclosure 3 includes the BRIIE results for FY 2015. None of the tracked initiating events 

exceeded their prediction limits. 

Results of FY 2015 Replaced Indicators 

The ITP indicators were revised in January 2016 and some statistical analyses for the new 

indicators remains to be completed. During this transition period the staff also reviewed the 

indicators that were recently removed from the ITP. Enclosure 4 shows the long-term and 

short-term results for these indicators. 

None of the short-term indicators exceeded their prediction limits in FY 2015. However, a 

statistically significant adverse trend was observed for the Safety System Failures (SSF) 

long-term indicator during the FY 2006 to FY 2015 timeframe. 

This statistically significant adverse trend did not result from an unusually high FY 2015 value. 

In fact, SSF values have been relatively constant around the baseline period average for the 

last six FYs (2010 to 2015). The statistically significant adverse trend was caused by the ten 

year plot for SSFs now beginning with FY 2006 data. FY 2006 to FY 2009 values are the lowest 

in the 28 year history of the SSF indicator and are the only years in the history of the ITP in 

which the SSF values vary significantly from the baseline average, so they are considered to be 

outliers by the ITP. The unusually good performance in SSFs during the FY 2006 to FY 2009 

timeframe combined with the return to historically normal levels of performance during the FY 

2010 to FY 2015 timeframe strongly influence the data and cause a statistically significant 

adverse trend. Since this trend was caused by outliers in the data, it does not require any 

generic actions, as outlined in IMC 0313. 

The Safety System Functional Failure (SSFF) ROP PI is one of the new indicators for which the 

full statistical analysis has yet to be completed and will be included in next year’s industry trends 

analysis. Given its similarity to the SSF indicator, it is possible that the new SSFF indicator 

would have displayed a similar adverse trend. 
The Commissioners - 5 - 

CONCLUSION: 

The FY 2015 ITP evaluation did not indicate any trends in industry safety performance that 

required generic actions. Also, no ITP indicator or initiating events tracked by the BRIIE 

exceeded their prediction limits. 

RESOURCES: 

The resources for ITP activities are included in the FY 2016 Current Estimate (CE) and the FY 

2017 Congressional Budget Justification (CBJ). The total resources that are included in both 

the FY 2016 CE and FY 2017 CBJ are 0.5 full-time equivalent (FTE) and $535K. No additional 

resources beyond those already budgeted will be required for the ITP. Staff has proposed 

elimination of the ITP as outlined in SECY-16-0009, “Recommendations Resulting from the 

Integrated Prioritization and Re-Baselining of Agency Activities,” and will await Commission 

direction from that paper. If the Commission approves the reduction, the 0.5 FTE and the 

portion of the $535k contract dollars associated with the ITP in the FY 2017 CBJ will be cut. If 

the program is maintained, resources beyond FY 2016 will be addressed during the Planning, 

Budgeting, and Performance Management process. 

COORDINATION: 

The Office of the Chief Financial Officer has reviewed this paper for resource implications and 

has no objections. The Office of the General Counsel has reviewed this paper and has no legal 

objection. 

 /RA/ 

 

William M. Dean, Director 

Office of Nuclear Reactor Regulation 

Enclosures: 

1. Fiscal Year 2015 Long-Term Industry Trend 

 Results 

2. Fiscal Year 2015 Short-Term Industry 

 Performance 

3. Summary of Baseline Risk Index for 

Initiating Events: Annual Graphs through 

Fiscal Year 2015 

4. Fiscal Year 2015 Results for Recently 

 Replaced Industry Trend Indicators 
The Commissioners - 5 - 

CONCLUSION: 

The FY 2015 ITP evaluation did not indicate any trends in industry safety performance that 

required generic actions. Also, no ITP indicator or initiating events tracked by the BRIIE 

exceeded their prediction limits. 

RESOURCES: 

The resources for ITP activities are included in the FY 2016 Current Estimate (CE) and the FY 

2017 Congressional Budget Justification (CBJ). The total resources that are included in both 

the FY 2016 CE and FY 2017 CBJ are 0.5 full-time equivalent (FTE) and $535K. No additional 

resources beyond those already budgeted will be required for the ITP. Staff has proposed 

elimination of the ITP as outlined in SECY-16-0009, “Recommendations Resulting from the 

Integrated Prioritization and Re-Baselining of Agency Activities,” and will await Commission 

direction from that paper. If the Commission approves the reduction, the 0.5 FTE and the 

portion of the $535k contract dollars associated with the ITP in the FY 2017 CBJ will be cut. If 

the program is maintained, resources beyond FY 2016 will be addressed during the Planning, 

Budgeting, and Performance Management process. 

COORDINATION: 

The Office of the Chief Financial Officer has reviewed this paper for resource implications and 

has no objections. The Office of the General Counsel has reviewed this paper and has no legal 

objection. 

 

William M. Dean, Director 

Office of Nuclear Reactor Regulation 

Enclosures: 

1. Fiscal Year 2015 Long-Term Industry Trend 

 Results 

2. Fiscal Year 2015 Short-Term Industry 

 Performance 

3. Summary of Baseline Risk Index for 

Initiating Events: Annual Graphs through 

Fiscal Year 2015 

4. Fiscal Year 2015 Results for Recently 

 Replaced Industry Trend Indicators 

 200100034 

ADAMS Accession Number: ML16050A462 *concurred via email

OFFICE NRR/DIRS/IPAB BC:NRR/DIRS/IPAB BC:NRR/DIRS/IOEB* D:NRR/DIRS 

NAME AWaugh NSanfilippo HChernoff SMorris (CJohnson for) 

DATE 02/18/2016 03/03/2016 03/09/2016 03/11/2016 

OFFICE OGC (NLO)* RES* NSIR D:NRR 

NAME SFowler MWeber BHolian WDean 

DATE 03/11/2016 03/24/2016 03/24/2016 04/05/2016 

OFFICIAL RECORD COPY
Enclosure 1 

FISCAL YEAR 2015 LONG-TERM INDUSTRY TREND RESULTS 

The staff of the U.S. Nuclear Regulatory Commission did not identify any statistically significant 

adverse trends in the industry trends program performance indicator data from the most recent 

10 years (fiscal years 2006–2015), as shown by the figures below. 

As a reminder, the statistical analysis for some of the newly implemented ITP indicators is still 

ongoing and will be completed during calendar year 2016. This paper presents results for the 

ITP indicators that have a completed statistical analysis. 

Figure 1. Unplanned scrams

0.48

0.68

0.49

0.62

0.69

0.59

0.50

0.58 0.57 0.54

0.0

0.5

1.0

1.5

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Unplanned scrams per 

7,000 Critical Hours

Fiscal Year

Industry Average
- 2 - 

Figure 2. Unplanned power changes 

Figure 3. Unplanned scrams with complications

0.91 0.91 0.92

0.56

0.86 0.89

0.70 0.76

0.95

0.50

0.0

0.5

1.0

1.5

2.0

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Unplanned Power Changes per 

7,000 Critical Hours

Fiscal Year

15

8

6

7

8

11

13

10

14

0

5

10

15

20

25

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Scrams

Fiscal Year

Industry Average

Industry Average
- 3 - 

Figure 4. Reactor coolant system activity

Figure 5. Reactor coolant system leakage

0.60

0.45 0.48

0.32

0.19

0.13

0.09 0.08 0.11

0.07

0.0

0.5

1.0

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Maximum Percentage of Technical

Specification Limits

Fiscal Year

4.08

4.35 4.25

3.97 4.14 4.05 4.08 3.99 4.02 3.91

0

2

4

6

8

10

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Maximum Percentage of

Technical Specification Limits

Fiscal Year

Industry Average

Industry Average Trend

Industry Average

Industry Average Trend
- 4 - 

Figure 6. Drill and exercise performance 

Figure 7. Emergency response organization drill participation

96.06 96.19 96.22

97.06 96.89

97.30 97.51 97.47

97.86

98.21

92

94

96

98

100

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Percentage Timely and Accurate

Fiscal Year

97.89

97.55

98.16

98.65

98.77

99.43 99.33

99.46

99.71 99.84

96

98

100

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Percentage of Key Personnel

Fiscal Year

Industry Average

Industry Average Trend

Industry Average

Industry Average Trend
- 5 - 

Figure 8. Alert and notification system reliability 

Figure 9. Occupational exposure control effectiveness 

99.48 99.45

99.53 99.57 99.59

99.68 99.77

99.77 99.78 99.81

98

99

100

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Percentage of Tests Successful

Fiscal Year

8

12

14

5

10

11

14

10

7

5

0

10

20

30

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Number of Radiological Occurrences

Fiscal Year

Industry Average

Industry Average Trend

Industry Average
- 6 - 

Figure 10. Radiological effluent technical specifications and offsite dose calculations 

manual radiological effluent occurrences 

Figure 11. Protected area security equipment performance index

00000

1

0000

0

1

2

3

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Number of Occurrences

Fiscal Year

1.84 1.80 1.89 1.81

1.98

2.15

1.94

1.68 1.60

1.39

0

1

2

3

4

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Index

Fiscal Year

Industry Average

Industry Average
Enclosure 2 

FISCAL YEAR 2015 SHORT-TERM INDUSTRY PERFORMANCE

The annual industry trend analysis compares 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 indicator. Baseline periods are periods for each indicator during which the data can be 

regarded as fairly constant and indicative of “current” performance. 

The results of the evaluation for fiscal year (FY) 2015 Industry Trends Program (ITP) indicators, 

using the established prediction limits, show that no indicator exceeded its associated prediction 

limit in FY 2015, as shown in the figures below. 

As a reminder, the statistical analysis for some of the newly implemented ITP indicators is still 

ongoing and will be completed during calendar year 2016. This paper presents results for the 

ITP indicators that have a completed statistical analysis, therefore no short-term graphs are 

shown for indicators which do not have a finalized prediction limit. 

Figure 1. Unplanned power changes per 7,000 critical hours 

0.0

0.5

1.0

1.5

2.0

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Unplanned Power Changes per 

7,000 Critical Hours

Fiscal Year

Industry Average

Prediction Limit 1.30

Baseline Industry Average (1.11), 2001-2004
- 2 - 

Figure 2. Reactor coolant system activity 

Figure 3. Reactor coolant system leakage

Note that the steam generator tube rupture event at Indian Point Nuclear Generating Unit 2 in 

2000 was not included in the short-term data for determining prediction limits in Figure 3. This 

event was excluded from the development of the prediction limit models because it was 

considered as an outlier that could overly influence the statistical analysis of the industrywide 

data. This treatment results in a more conservative prediction limit. 

0.00

0.25

0.50

0.75

1.00

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Maximum Percentage of Technical 

Specification Limits

Fiscal Year

Industry Average

Prediction Limit (0.646)

Baseline Industry Average (0.462), 2001-2004

0

2

4

6

8

10

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Maximum Percentage of Technical 

Specification Limits

Fiscal Year

Industry Average

Prediction Limit (6.32)

Baseline Industry Average (5.14), 2000-2004
- 3 - 

Figure 4. Drill and exercise performance 

Figure 5. Emergency response organization drill participation 

92

94

96

98

100

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Percentage Timely and Accurate

Fiscal Year

Industry Average

Prediction Limit (95.21)

Baseline Industry Average (95.62), 2000-2004

94

96

98

100

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Percentage of Key Personnel

Fiscal Year

Industry Average

Prediction Limit (97.50)

Baseline Industry Average (97.87), 2003-2007
- 4 - 

Figure 6. Alert and notification system reliability 

97

98

99

100

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Percentage of Tests Successful

Fiscal Year

Industry Average

Prediction Limit (98.35)

Baseline Industry Average (98.87), 2001-2004
Enclosure 3 

SUMMARY OF BASELINE RISK INDEX FOR INITIATING EVENTS: 

ANNUAL GRAPHS THROUGH FISCAL YEAR 2015 

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 Process 

(ROP) for monitoring commercial nuclear power plants. It is based on plant performance for the 

10 initiator events listed in the table below. 

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 alternating 

current bus LOAC Both plant types 

Loss of vital direct current 

bus LODC Both plant types 

Stuck-open safety or relief 

valve SORV Both plant types, separately 

Loss of instrument air LOIA Both plant types, separately 

Very small loss-of-coolant 

accident VSLOCA Both plant types 

Steam generator tube 

rupture SGTR Pressurized-water reactors 

(PWRs) only 

The BRIIE program is described in NUREG/CR-6932, “Baseline Risk Index for Initiating Events 

(BRIIE),” issued June 2007. The BRIIE considers individual IEs and evaluates performance 

based on statistical prediction limits. This evaluation is for the ongoing monitoring and early 

detection of possible industry-level deficiencies. Because four of the initiators have separate 

data for each plant type, there are 14 IE frequency graphs. 

The units for the IE frequency graphs are event counts for a fiscal year divided by the industry 

critical time for the year. The 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. If industry data shift as time progresses, the baseline 

periods used to determine the prediction limits might no longer be relevant. The periods 

originally were developed to describe, roughly, calendar years 1998–2002. 

The prediction limits depend on the expected critical years of reactor operation in the upcoming 

year and the baseline occurrence rate for each indicator. A rate can exceed a limit by having 

more events than expected or by having the same number of events and less critical time than 

expected. In recent years, U.S. nuclear power plant availability has been about 90 percent at 

the industry level. This figure enters into the calculations that determine the bounds on the 

number of events that might be expected. 

None of the fiscal year 2015 occurrence rates exceeded their prediction limits. 
- 2 - 

Figure 1. Pressurized-water reactor (PWR) general transients 

Figure 2. Boiling-water reactor (BWR) general transients 

0.52

0.65

0.56 0.57

0.87

0.66

0.44

0.57

0.64 0.63

0.0

0.5

1.0

1.5

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1998 - 2002 Fiscal Year

Baseline industry average

95% prediction limit for one year

0.56

0.97

0.55

0.84

0.63

0.47

0.65 0.66 0.63 0.59

0.0

0.5

1.0

1.5

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Fiscal Year Baseline period: 1997 - 2002

Baseline industry average

95% prediction limit for one year
- 3 - 

Figure 3. PWR loss of condenser heat sink

Figure 4. BWR loss of condenser heat sink 

0.064

0.032

0.016

0.047

0.082

0.033 0.034 0.034

0

0.016

0.00

0.05

0.10

0.15

0.20

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1995 - 2002 Fiscal Year

Baseline industry average

95% prediction limit for one year 

0.031

0.16

0.091 0.093

0.060 0.063 0.062 0.063

0

0.062

0.0

0.1

0.2

0.3

0.4

0.5

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1996 - 2002 Fiscal Year

Baseline industry average

95% prediction limit for one year 
- 4 - 

Figure 5. Loss of main feedwater

Figure 6. Loss of offsite power 

The prediction limit for loss of offsite power was calculated under the assumption that the eight 

at-power events that occurred during the 2003 blackout were a single event. This treatment 

results in a more conservative prediction limit.

0.042

0.063

0.042 0.042

0

0.022

0.011

0.033

0.011

0.032

0.00

0.05

0.10

0.15

0.20

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Fiscal Year Baseline period: 1993 - 2002

Baseline industry average

95% prediction limit for one year 

0.021

0.011

0

0.031

0

0.075

0.055

0.044

0.033

0.011

0.00

0.05

0.10

0.15

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1997 - 2004 Fiscal Year

Baseline industry average

95% prediction limit for one year 
- 5 - 

Figure 7. Loss of vital alternating-current bus

Figure 8. Loss of vital direct-current bus

0000

0.021

0

0.011

000

0.00

0.02

0.04

0.06

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1992 - 2002 Fiscal Year

Baseline industry average

95% prediction limit for one year

000 0 0

0.011

0 0 0 0

0.00

0.01

0.02

0.03

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1988 - 2002 Fiscal Year

Baseline industry average

95% prediction limit for one year
- 6 - 

Figure 9. PWR stuck-open safety or relief valve

Figure 10. BWR stuck-open safety or relief valve

0000000000

0.00

0.01

0.02

0.03

0.04

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Fiscal Year Baseline period: 1988 - 2002

Baseline industry average

95% prediction limit for one year

000

0.031

000000

0.00

0.03

0.06

0.09

0.12

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1993 - 2002 Fiscal Year

Baseline industry average

95% prediction limit for one year
- 7 - 

Figure 11. PWR loss of instrument air 

Figure 12. BWR loss of instrument air

0.016 0.016

0 0

0.016

0 0

0.017 0.017

0

0.00

0.02

0.04

0.06

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Fiscal Year Baseline period: 1997 - 2002

Baseline industry average

95% prediction limit for one year

0.031

0000000

0.030

0

0.00

0.02

0.04

0.06

0.08

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1991 - 2002 Fiscal Year

Baseline industry average

95% prediction limit for one year
- 8 - 

Figure 13. Very small loss-of-coolant accident

Figure 14. PWR steam generator tube rupture 

0 0 0 0 0 0 000 0

0.00

0.01

0.02

0.03

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1992 - 2002 Fiscal Year

Baseline industry average

95% prediction limit for one year

0000000000

0.00

0.01

0.02

0.03

0.04

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per reactor critical year

Baseline period: 1991 - 2002 Fiscal Year

Baseline industry average

95% prediction limit for one year
Enclosure 4 

FISCAL YEAR 2015 RESULTS FOR RECENTLY REPLACED INDUSTRY 

TREND INDICATORS 

To provide continuity while transitioning to the use of Reactor Oversight Process performance 

indicator data for the Industry Trends Program (ITP), the staff of the U.S. Nuclear Regulatory 

Commission also evaluated the recently replaced ITP indicators. These indicators (with the 

exception of Accident Sequence Precursors) were each evaluated for both long-term statistically 

significant trends and short-term comparison against the noted baseline industry average and 

pre-established prediction limit. As noted in the main body of the paper, the staff identified a 

statistically significant adverse trend for the Safety System Failure indicator from fiscal year (FY) 

2006 to FY 2015 caused by outliers in the data and does not require any generic actions. None 

of the indicators exceeded the short-term prediction limit in FY 2015. The previous revision of 

IMC 0313, “Industry Trends Program,” dated May 29, 2008 (ADAMS Accession 

No. ML080860540), contains definitions and details on these ITP indicators that have recently 

been replaced. 

Figure 1. Accident sequence precursors (FY 2005-2014)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

Precursors Occurrence per Unit

Fiscal Year

Industry Average
- 2 - 

Figure 2. Automatic scrams while critical long-term results 

Figure 3. Automatic scrams while critical short-term results 

0.32

0.48

0.29

0.36

0.44 0.45

0.30

0.38 0.39 0.38

0.00

0.25

0.50

0.75

1.00

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Scrams per Unit

Fiscal Year

0.00

0.25

0.50

0.75

1.00

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Scrams per Unit

Fiscal Year

Industry Average

Prediction Limit (0.673)

Baseline Industry Average (0.534), 1997-2002

Industry Average
- 3 - 

Figure 4. Safety-system actuations long-term results 

Figure 5. Safety-system actuations short-term results 

0.22

0.25

0.14

0.23

0.18 0.19

0.17

0.29

0.20

0.15

0

0.2

0.4

0.6

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Actuations per Unit

Fiscal Year

0.00

0.20

0.40

0.60

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Actuations per Unit

Fiscal Year

Industry Average

Prediction Limit (0.375)

Baseline Industry Average (0.275), 1998-2005

Industry Average
- 4 - 

Figure 6. Significant events long-term results 

Figure 7. Significant events short-term results 

0.03

0.02

0.03

0.02

0.10

0.13

0.10

0.07

0.03

0.01

0.00

0.05

0.10

0.15

0.20

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per Unit

Fiscal Year

0.00

0.05

0.10

0.15

0.20

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Events per Unit

Fiscal Year

Industry Average

Prediction Limit (0.106)

Baseline Industry Average (0.524), 2000-2004

Industry Average
- 5 - 

Figure 8. Safety-system failures long-term results 

Figure 9. Safety-system failures short-term results 

0.60

0.66 0.71 0.71

0.88 0.90 0.85

0.93 0.85 0.92

0.0

0.5

1.0

1.5

2.0

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Failures per Unit

Fiscal Year

0.00

0.50

1.00

1.50

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Failures per Unit

Fiscal Year

Industry Average

Prediction Limit (1.04)

Baseline Industry Average (0.859), 2001-2004

Industry Average

Industry Average Trend
- 6 - 

Figure 10. Forced outage rate long-term results 

Figure 11. Forced outage rate short-term results 

1.47 1.41 1.34

2.21

1.74 1.80

2.77

2.98

1.27 1.10

0

2

4

6

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Forced Outage Rate (%)

Fiscal Year

0

2

4

6

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Forced Outage Rate (%)

Fiscal Year

Industry Average

Prediction Limit (4.28)

Baseline Industry Average (2.40), 2001-2004

Industry Average
- 7 - 

Figure 12. Equipment forced outages long-term results 

Figure 13. Equipment forced outages short-term results 

0.10

0.11

0.08

0.09

0.10

0.09 0.09

0.08

0.10

0.08

0

0.1

0.2

0.3

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Equipment Forced Outages per

1,000 Commercial Critical Hours

Fiscal Year

0.00

0.05

0.10

0.15

0.20

0.25

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Equipment Forced Outages per

1,000 Commercial Critical Hours

Fiscal Year

Industry Average

Prediction Limit (0.180)

Baseline Industry Average (0.142), 1998-2004

Industry Average
- 8 - 

Figure 14. Collective radiation exposure long-term results 

Figure 15. Collective radiation exposure short-term results 

93

109

96

87 91 90

72 77

70 68

0

50

100

150

200

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Average Exposure per Unit

(Person-REM)

Fiscal Year

0

50

100

150

200

2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Average Exposure per Unit 

(Person-REM)

Fiscal Year

Industry Average

Prediction Limit (139)

Baseline Industry Average (119), 1999-2002

Industry Average

Industry Average Trend