R e a c t o r 

Oversight 

PROCESS

NUREG/BR-0508 Rev. 1

April 2016

STAY CONNECTED

Figure 3. NRC response plan to ROP assessment of plant performance

NRC Response to Plant Performance

The NRC determines its regulatory response in 

accordance with an Action Matrix (see Figure 3). 

This matrix objectively ranks plant performance 

based on the significance of the inspection 

findings and PIs. The Action Matrix provides 

consistent, predictable, and understandable 

agency responses to licensee performance. As 

illustrated in Figure 3, NRC increases oversight 

as licensee performance declines. 

Communications

The NRC assesses plant performance 

continuously and issues letters summarizing 

plant performance every six months. The 

NRC posts these assessment letters on 

each plant’s performance summary public 

website, and conducts public meetings with 

licensees to discuss plant performance. 

Other information available through the 

plant’s website includes:

• quarterly PI data

• significant inspection findings

• inspection reports

Individual plant performance information and 

additional information about the ROP can be 

accessed through the following website: 

http://www.nrc.gov/NRR/OVERSIGHT/

ASSESS/index.html

Contact Us

The NRC’s Performance Assessment Branch 

welcomes comments and questions from 

members of the public regarding the Reactor 

Oversight Process. These can be submitted 

via the form located at:

http://www.nrc.gov/NRR/OVERSIGHT/

ASSESS/contactus.html

photo courtesy FPL

Response at Agency Level • Meeting with NRC Executive Director for Operations and senior 

plant management 

• Order to modify, suspend, or revoke licenseResponse at Agency Level • Meeting with NRC Executive Director for Operations and senior plant 

management 

• Plant operator improvement plan with NRC oversight • NRC team inspection focused on performance issues at the site • Demand for Information, Confirmatory Action Letter, or Order Response at Regional Level • Meeting with NRC regional management and senior plant management• Plant operator self-assessment with NRC oversight • Additional NRC inspections focused on cause of degraded performanceResponse at Regional Level • Meeting with NRC and plant management • Plant operator corrective actions to address WHITE inputs • NRC inspection to follow up on WHITE inputs and corrective actionsNormal Regional Oversight • Routine inspector and staff interaction• Baseline inspection program •

NRC Response

 Annual assessment public meeting

Column 5. Unacceptable PerformanceColumn 4. Multiple/Repetitive Degraded Cornerstone

Repetitive degraded cornerstone, multiple degraded cornerstones, or multiple YELLOWinputs, or one RED input 

Column 3. Degraded Performance 

One degraded cornerstone (three WHITE inputs or one YELLOW input in a cornerstone) or three WHITE inputs in any strategic performance area 

Column 2. Regulatory Response

No more than two WHITE inputs in a strategic performance area 

Column 1. Licensee Response

All performance indicators and cornerstone inspection findings GREEN

ROP Action Matrix Asessment of Plant Performance

Increasing Safety Significance

Increasing Regulatory Oversight
• Emergency Preparedness: this measures the 

effectiveness of the plant’s staff to carry out 

emergency plans to respond effectively to a 

possible accident 

• Occupational Radiation Safety: this monitors 

the effectiveness of the plant’s program 

to protect worker’s health and safety from 

exposure to radiation

• Public Radiation Safety: this monitors the 

effectiveness of the plant’s program to protect public 

health and safety from exposure to radioactive 

materials released beyond the plant’s boundaries

• Security: this monitors the plant’s physical 

protection systems and ability to defend the 

plant against attack

Cross-Cutting Areas

In addition to the cornerstones, the ROP features 

three “cross-cutting” areas that can affect each 

of the cornerstones:

• human performance

• problem identification and resolution 

• safety-conscious work environment

These cross-cutting areas are considered during 

all NRC inspections and are covered during 

periodic plant assessments. 

Plant Assessment

The NRC’s plant evaluations are based on two 

distinct inputs:

• findings from the NRC’s inspection program 

• performance indicators (PIs) reported by the 

licensee 

The NRC gives both PIs and inspection findings 

a color designation based on their safety 

significance (see Figure 2).

Inspection Program

The NRC’s inspection program starts with 

the “baseline” inspections done at every U.S. 

nuclear plant. Baseline inspections represent 

the minimum level of inspection required to 

ensure plant safety and security. Baseline 

inspections focus on activities and systems 

that are significant to plant safety and security 

(e.g., those activities and systems that could 

trigger an accident or could either reduce or 

increase a potential accident’s consequences). 

Inspections beyond the baseline program are 

performed in response to specific events at a 

plant or changes in a plant’s performance.

The NRC’s Significance Determination Process 

determines the importance of inspection 

findings and associated violations.

Performance Indicators

Each PI objectively measures performance 

according to established safety margins. The 

plants compile the indicators and report them 

to the NRC quarterly. The NRC validates the 

licensees’ reported PIs.

What is the Reactor Oversight Process?

The U.S. Nuclear Regulatory Commission’s 

(NRC’s) Reactor Oversight Process (ROP) is the 

agency’s program to inspect, measure, and assess 

the safety and security performance of commercial 

nuclear power plants. It also responds to declining 

licensee performance. The ROP contributes 

to the NRC’s mission of ensuring public health 

and safety, promoting the common defense and 

security, and protecting the environment during 

the operation of commercial nuclear power plants 

by monitoring plant performance in three strategic 

performance areas: 

• Reactor Safety: avoiding accidents and reducing 

the consequences of accidents if they occur

• Radiation Safety: protecting both plant 

workers and the public from unnecessary 

radiation exposure during routine operations

• Safeguards: protecting the plant against 

sabotage and other security threats 

Cornerstones of Safe Operation

The seven “cornerstones” of the ROP support the 

three strategic performance areas by monitoring 

and measuring plant performance (see Figure 1). 

The cornerstones cover the following:

• Initiating Events: this focuses on limiting the 

occurrence of the events that could disrupt 

plant operations and challenge safety functions

• Mitigating Systems: this monitors the function 

of the plant’s safety systems designed to 

reduce the effects of initiating events

• Barrier Integrity: this monitors the physical 

barriers (fuel cladding, reactor coolant system, 

and containment) that protect the public from 

releases of radioactive material caused by 

accidents or events

Green: very low safety significance

(for findings), expected

performance (for PIs)

White: low-to-moderate safety

significance

Yellow: substantial safety 

significance

Red:	 high safety significance

Figure 2. Safety significance color designation

Figure 1. Reactor oversight framework

Reactor Oversight Framework

Protect Public Health and Safety in the Use of Nuclear Power

Reactor Safety

Initiating

Events

Mitigating

Systems

Barrier

Integrity

Public 

Radiation

Security

Safety Conscious Work Environment Problem Identification and Resolution Human Performance

Mission

Strategic 

Performance 

Areas

Cornerstones

Cross-Cutting 

Areas

Occupational

Radiation

Emergency 

Preparedness

Radiation Safety Safeguards