R e a c t o r 

Oversight 

PROCESS

NUREG/BR-0508

March 2013

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@NRC.gov

NRC Response

Response at Agency LevelResponse 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 and senior regional management and 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 actionNormal Regional Oversight • Routine inspector and staff interaction• Baseline inspection program • Annual assessment public meeting

ROP Action Matrix Asessment of Plant Performance

Column 5. Unacceptable PerformanceColumn 4. Repetitive degraded cornerstone, multiple 

degraded cornerstones, or multiple YELLOWinputs, or one RED input 

Column 3. One degraded cornerstone (two WHITE inputs or 

one YELLOW input or three WHITE inputs in any strategic area) 

Column 2. No more than two WHITE inputs in different 

cornerstones 

Column 1. All performance indicators and cornerstone 

inspection findings GREEN

Increasing Safety Significance

Increasing Regulatory Oversight

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 6 months. The NRC 

posts these assessment letters on each 

plant’s performance summary public Web 

site, and conducts public meetings with 

licensees to discuss plant performance. 

Other information available through the 

plant’s Web site includes the following:

• quarterly performance indicator data

• significant inspection findings

• inspection reports

Individual plant performance information 

and additional information about the ROP 

can be accessed through the following 

Web site: 

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

ASSESS/index.html

photo courtesy FPL
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 from radioactive material

• Public Radiation Safety: this monitors the 

effectiveness of the plant’s program to protect 

public health and safety from exposure to 

radioactive materials released into the public 

domain

• 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. These are as follows:

• 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. Baselines 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 performance indicator objectively 

measures performance according to 

established safety margins. The plants 

compile the indicators and report them to the 

NRC quarterly.

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 any decline in performance. The 

ROP contributes to the NRC’s mission of 

ensuring public health and safety during the 

operation of commercial nuclear power plants by 

monitoring plant performance in three key 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 or other security threats 

Cornerstones of Safe Operation

The seven “cornerstones” of the ROP support 

the three key 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 design 

barriers (fuel cladding, reactor coolant system, 

and containment) that protect the public from 

radionuclide releases caused by accidents or 

events

• Emergency Preparedness: this measures the 

effectiveness of the plant’s staff to carry out 

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

Key Areas

Cornerstones

Cross-Cutting 

Areas

Occupational

Radiation

Emergency 

Preparedness

Radiation Safety Safeguards