• EPM Inc.

    Framingham, MA
    Raleigh, NC

    +1 508-875-2121



(Duration: 2 ½ days) This course is an introduction into the methodology and current state-of-the-art techniques of Probabilistic Risk Assessment (PRA). The full spectrum of PRA is covered in this course with the goal of introducing the participant to basic fundamentals of risk and PRA concepts in order to better understand the methods and uses of this decision making tool. The course is taught using an interactive interface which keeps the participant involved in discussions and exercises.


·   Discuss the history of nuclear power safety and the background of PRA.

·   Relate the basic concepts of risk and safety  analysis to Probabilistic Risk Assessment.

·   Examine nuclear safety design methodologies and show how PRA is applied.

·   Describe the fundamental essentials of a full PRA.

·   Explain the role of PRA in decision making and industry application.

·   Recognize the importance of PRA quality and the role it has in analyzing risk.


This course is designed for the individual who requires knowledge in PRA techniques to better evaluate the effects of design, testing, maintenance, and operation of systems for daily decision making.


Day 1   (8:30am – 4:30pm)

Basic Risk Concepts of PRA

What is Risk
Approaches to Studying Risk
Risk Matrix
History of PRA

Nuclear Safety Design

Treatment of Accidents in Design
Deterministic Safety Analysis
Defense-in-Depth Philosophy
Use of Probabilistic Risk Assessment in Design
NRC Compliance in Nuclear Power Plant Design and Operation

What is PRA?

Probability Operations and Concepts
Frequency vs. Probability
Probability Distribution Models
Cut Sets and Quantification Methods

Event Tree Analysis

Event Tree Methodology
Initiating Events
Event Tree Construction

Fault Tree Analysis

Fault Tree Methodology
Fault Tree Development Process
Fault Tree Construction
Success Criteria
Fault Tree Logic and Boolean Reduction

Day 2   (8:30am – 4:30pm)

Failure Data

Failure Modes
Data Sources

Human Reliability Analysis

Human/System interaction
Categories of Human Errors
Human Reliability Analysis Techniques
Integrating HRA in PRA
Performance Shaping Factors

Generating Sequences

Inputs to Quantification
Approaches to Sequence Quantification (i.e. Fault Tree Linking)
Sequence Logic
Recovery Actions

Importance Measures

Risk Achievement Worth
Birnbaum Importance

Day 2 (Cont.)

Uncertainty in PRA

Aleatory and Epistemic Uncertainty
Uncertainty Distributions

External Event Analysis
History of External Events and IPEEEs
Seismic Analysis
Fire PRA and NFPA 805 Transition
Flood and High Wind Analysis

low Power and Shutdown PRA

Low Power and Shutdown (LPSD) Characteristics
Factors That Increase Risk During Shutdown
LPSD PRA Format and Findings
Use of Risk Monitors during LPSD

Level II and Level III PRA
Purpose of Level II and Level III PRA
Level II – Accident Progression Analysis
Level II Software Overview
Level III – Consequence Analysis
Level III Software Overview
Accident Sequences

Day 3   (8:30am – noon)

Safety Systems and PRA

Safety Design
Generic Letter 88-20 (Request for Individual Plant Examination (IPE))
IPE Requirements

PRA Applications in Industry

PRA uses by other Industries
Airline Industry PRA Philosophy
NASA PRA Philosophy
PRA Applications in Decision Making
NRC Policy Statement
NRC Framework and Risk Informed Regulation (Regulatory Guide 1.174)
Risk Informed Decision Making
Overview of the “Maintenance Rule” and the NRC Reactor Oversight Process (ROP)
Significance Determination Process (SDP)
Mitigating Systems Performance Index (MSPI)
Design Certification and COLs

PRA Quality

PRA Quality Elements
NRC Approach to PRA Quality (Regulatory Guide 1.200)
American Society of Mechanical Engineers (ASME) Standard for PRA Quality



(Duration: 1 day) This course discusses the methodology and guidelines used in performing circuit analysis in accordance to current industry regulation and guidelines (NUREG/CR-6850, NEI 00-01, RG 1.205, RG 1.189). Topics include circuit failure modes, adverse effects on component function, and isolated circuits



(Duration: 3 ½ days) This class will study accepted methodologies required to analyze and model the impacts of fire and smoke. The course covers basic theory of fire behavior and characteristics, scoping fire modeling, detailed fire spread and growth analysis, detection and suppression analysis, transient fire analysis, and fire modeling verification and validation, as required by NFPA 805. The course will cover current state-of-the-art fire modeling methods and techniques, including NUREG/CR-6850 methodologies, NUREG-1805 FDTs, and NUREG-1934 – Fire Modeling Analysis Guide, and an introduction to CFAST and FDS.



(Duration: 1 ½ days) Discusses in detail the safety significant topic of seismic hazards and risk assessment including issues relevant to NRC Generic Issue 199 “Implications of Updated Probabilistic Seismic Hazard Estimates in Central and Eastern United States on Existing Plants” and the NRC’s Japan Near Term Task Force (NTTF) Recommendations. Topics include an overview of seismic analysis methods and terminology, seismic margins approach, seismic hazard evaluation, fragility methodology, and Seismic PRA accident sequences and quantification.


·   Discuss the history of Seismic Risk Analysis and the background of IPEEEs.

·   Familiarize participants with the terminology and approaches used to assess seismic hazards and risks.

·   Relate the approaches of Seismic Margin and of Seismic Probabilistic Risk Assessment (SPRA) and explain their differences.

·   Describe the state-of-the-art methods for performing ASME PRA Standard requirements to Seismic PRAs and for satisfying future NRC requirements.

·   Explain seismic hazard evaluation methods and the concept of seismic fragility using basic principles and examples.


This course is designed for the individual who requires knowledge, background and a better understanding for the approaches and methodologies behind seismic risk assessment to address the anticipated NRC seismic-related initiatives expected in 2012.


Day 1 (8:30am – 4:30pm)

Risk Concepts of PRA
What is Risk
Approaches to Studying Risk
Risk Matrix
History of PRA

Risk and Seismic Hazard Review
What is a Seismic Hazard
Seismic Terminology
Earthquake Characteristics
Overview of the IPEEE Approach for Seismic Risk Vulnerabilities
Applicable Regulatory Requirements for Seismic Design and Analysis

Seismic Hazard Assessment

Overview of Seismic Analysis Methodologies
NRC/EPRI Seismic Hazard Analysis
Seismicity Models
Ground Motion Estimation
Peak Ground Acceleration
Probability of Exceedance
Seismic Hazard Curve Development

Seismic Fragility Evaluation

Structure Fragility
Component Fragility
Fragility Methodologies
Fragility Curves
Plant Walkdown Objectives and Findings

Seismic Margin Approach

NRC/EPRI Methodologies
HCLPF for Structures, Systems, and Components
Fault-space Based Logic Model
Failure Modes
Screening Criteria

Seismic PRA and Sequence Analysis

ASME PRA Standard Regarding Seismic PRAs
Seismic Initiating Events
Seismic Fragility Parameters
Sequence Modeling
Event Tree Linking Approach
Seismic Human Reliability Analysis
Containment Response



(Duration: 4-Week series, 4 1/2 days/week) This course is a detailed instructional class into the subject of Probabilistic Risk Assessment (PRA). The full spectrum of PRA methodology and current state-of-the-art techniques is covered in this course with the goal of covering both the fundamental techniques of PRA and the current implementation of PRA in industry. This includes regulatory risk-informed performance-based activities. The course is taught over a staggered 4 week schedule to reduce the impact of individual or company work schedules. Individuals are not required to complete the whole series. They have the choice of attending only the weeks that fit their needs. The course is designed to cover all aspects of PRA methodology and utilization to give the student a broad knowledge to implement PRA in risk informed industries and decision making. The course includes numerous in class workshops and exercises that integrates the use of risk assessment software codes into the workshops to allow the participant to gain a complete set of skills for using PRA.


·   Discuss the background of risk and safety analysis and the history of PRA.

·   Relate the basic concepts of risk and safety analysis to Probabilistic Risk Assessment.

·   Examine nuclear safety design methodologies and show how PRA is applied.

·   Describe the technical state-of-the art methodologies and techniques of PRA.

·   Gain experience using PRA in safety and risk assessment decision making.

·    Understand the role of PRA in decision making for design, construction, and operations of industry applications and regulatory affairs.

·    Recognize the importance of PRA quality using the ASME/ANS Probabilistic Risk Assessment Standard incorporated by both industry and government regulators.

·    Expand the participants skill set using popular risk assessment software.


This course is designed for the individual who needs a deeper understanding of PRA methodology and a greater appreciation for implementing PRA techniques in risk-informed decision making and the analyses of risk matrixes. The 4 week class accommodates those individuals that require a comprehensive coverage of probabilistic safety assessments so they can be immediately effective in a risk-informed performance based regulated nuclear industry. New utility or nuclear industry employees needing background and experience in the PRA process with respect to design, licensing, construction, plant operation and maintenance, or regulatory affairs should attend. Utility employees that are reassigning or changing job responsibilities to safety, design or operational support, or regulatory or operational compliance will gain exceptional insight into risk-informed decision making using PRA. Though the course is catered to the nuclear industry, it is very practical for individuals in other industry fields requiring the expertise of PRA for safety and risk assessment decision making, such as space and aerospace industries, chemical, transportation industries, and government agencies that lack comprehensive in-house PRA training that this course offers.


Week 1 – Foundation of PRA

Day 1 (8:30am – 4:30pm)
Lecture 1

Introduction to PRA

What, When, and Why?
Initiating Events
Event Tree Analysis
Risky Business
History of PRA
A Discussion About “Core Damage”
Other Industries Uses of PRA

Lecture 2

Event Tree Elements

ASME Standard on Sequences
Event Tree Logic
Sequence and Cutset Interpolation
Sequence and Cutset Generation
Using Risk Assessment Code

Day 2 (8:30am – 4:30pm)
Lecture 3

Fault Tree Analysis

ASME Standard on Fault Trees
Failure Rates
Single Failure Criterion
Active vs. Passive Failures
Data Analysis

Lecture 4

Risk Statistics

Risk Achievement Worth
Risk Reduction Worth
Risk Rankings

Day 3 (8:30am – 4:30pm)
Lecture 5

Success Criteria

ASME Standard Requirements for Success Criteria
Determination of Success Criterion

Lecture 6

Success Criteria (Cont.)

Decay Heat vs. Fission Power
Success Criteria Examples

Day 4 (8:30am – 4:30pm)
Lecture 7

Data Analysis

Sources of Data
Demand Failures
Mission Time Failures
Data Error Factors
Test and Maintenance Data
ASME Standard Requirements for Data Analysis
Data Groupings
Common Cause Failures
Bayesian Updating

Lecture 8

Initiating Events

ASME Standard Requirements for IE Analysis
Using the FSAR
IE Calculations

Day 5 (8:30am – 12:00pm)
Lecture 8 (Cont.)

Initiating Events (Cont.)

Pitfalls of IE Calculations
The LOOP Partitioned Initiator
Grouping of Initiators

Review of Week 1

Week 2 – PRA Advanced Topics

Day 1 (8:30am – 4:30pm)
Lecture 9

Human Reliablity Analysis (HRA)

ASME Standard Requirements for HRA
Recovery Actions
Performance Shaping Factors
HRA Methodologies
EPRI’s HRA Calculator

Lecture 10

Prohibited Configurations

Technical Specifications
Significance of Prohibited Configurations
10 CFR 50 Appendix A – Single Failures
Limiting Conditions for Operation (LCO)
Recovery Rules Addressing LCOs

Day 2 (8:30am – 4:30pm)
Lecture 11

Verification and Validation

Regulatory Guide 1.200
Peer Reviews
10 CFR 50.65 (a)(4)
Maintenance Rule Working Book
Internal Consistency
Risk Ranking

Lecture 12

Uncertainty Analysis

Departure from Nucleate Boiling (DNB)
Monte Carlo Process
HRA Uncertainty
Guidelines for Addressing Uncertainty

Day 3 (8:30am – 4:30pm)
Lecture 13

Truncation and Top Logic

Rules of Truncation
ASME Standard for Trunaction Rationale
Top Logic PRA Models

Lecture 14

Configuration-Specific Analysis

Consideration of Initiating Events
Periodic Tests
Repair Considerations

Day 4 (8:00am – 4:30pm)
Lecture 15

External Events

SBO Severity
Internal Flooding
External Flooding
Fukushima Lessons Learned
SG Dryout
High Winds and Tornadoes
ASME Standard Requirements for External Events

Lecture 16

Level II PRA

Fuel Assembly
Barriers to Release
ASME Standard Requirements for Level II PRA

Day 5 (8:30am – 12:00pm)
Lecture 16

Level II PRA (Cont.)

PRA Modeling for Level II

Review of Week 2

Week 3 – PRA Technologies & Applications

Day 1 (8:30am – 4:30pm)
Lecture 17


ASME Standard Requirements for Level III
Sample Method
Classification Schemes
Radionuclide Release
Meteorological Data
Offsite Exposure

Lecture 18

Qualitative and Blended Analysis

Traditional Engineering Analysis
ASME Standard Requirements on Qualitative Evaluation
Blending Analysis
Deterministic Analysis Examples

Day 2 (8:30am – 8:30pm)
Lecture 19

Fire and Seismic Analysis

ASME Standard on Fire PRA
Characteristic of Fire
Ignition Sources
Spurious Operations
NUREG/CR-6850 Review
Seismic Analysis
Seismic Hazards
Fragility Analysis

Lecture 20

Transition and Shutdown Risk

ASME Standard on Low Power/Shutdown Risk
Overview of Shutdown Mode
Shutdown Hazards
Boiling Time and Frequency
Transition Risk
Ramping Risk

Day 3 (8:30am – 4:30pm)
Lecture 21

Significance Determination Process (SDP) Part I

Management Directive 8.3
Inspection Teams
NRC Viewpoint
Levels of Significance
Reactor Oversight Process
How the SDP Works
Utility Role in SDP
SDP Phases
Color Confusions

Lecture 22

Significance Determination Process (SDP) Part II

Review of SDP Examples
SDP Politics
Delta CDF vs. CCDP

Day 4 (8:00am – 4:30pm)
Lecture 23

History of Tech Specs

Embedded Margin
NRC Perspective
Regulatory Framework
Tier 1 Procedure
Tier 2 and 3 Procedure

Lecture 24

Risk-Informed Technical Specifications (Part II)

PRA Quality (Regulatory Guide 1.200)
Model Details
Risk Informed Regulation (Regulatory Guide 1.174)

Day 5 (8:00am – 12:00pm)
Lecture 24 (Cont.)

Risk-Informed Technical Specifications (Part II) (Cont.)

NRC Risk Initiatives
Missed Surveillance
Initiative 4B

Review of Week 3

Week 4 – Risk-Informed, Performance-Based PRA Applications

Day 1 (8:30am – 4:30pm)
Lecture 25

Mitigating Systems Performance Indicators (Part I)

MSPI Overview
Reactor Oversight Process
Generation of the Indicators
MSPI Monitoring
Unavailability Index
Unreliabilty Index

Lecture 26

Mitigating Systems Performance Indicators (Part II)

MSPI Truncation
Common Cause Failure Effects
The MSPI Systems
Important Compotents
Margin Recovery

Day 2 (8:30am – 4:30pm)
Lecture 27

Maintenance Rule (Part I)

10 CFR 50.65(a)(4)
Maintenance Configuration
Regulatory Guide 1.182
NUMARC 93-01
Sample Calculation Example
Periodic Tests

Lecture 28

Maintenance Rule (Part II)

Tracking of Components
Documentation Requirements
Risk Management Actions
Configuration – Specific IEs
Heavy Load Analysis
Degraded Components
Shutdown Risk Considerations
Fire Risk Considerations
Long-Term Configurations

Day 3 (8:30am – 4:30pm)
Lecture 29

Risk-Informed in Service Inspection (Part I)

In Service Inspection Overview
Current Requirements
Regulatory Guide 1.178
ISI Process
Segment Determination
Operator Action
Piping Failure Potential
PRA Role

Lecture 30

Risk-Informed in Service Inspection (Part II)

Segment Definition Example
Rupture Example
Uncertainty Analysis
PRA Interpretation

Day 4 (8:00am – 4:30pm)
Lecture 31

Maintenance Rule (a)(1) Part I

10 CFR 50.65(a)(1)
Risk Informed vs. Risk Based
Performance Criteria
PRA Risk Significance
Classification Process

Lecture 32

Maintenance Rule (a)(1) Part II

Sample Problem
System vs. Component Criteria

Day 5 (8:00am – 12:00pm)
Lecture 32 (Cont.)

Maintenance Rule (a)(1) Part II (Cont.)

Modeling Limitations
Monitoring Intervals

Review of Week 4

Future of PRA

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EDISON User Training


(Duration: 1 day) (Duration: 2 Days) This hands-on training will cover the use of the Genesis Solution Suite® cable and raceway module EDISON. The course covers application navigation, querying for specific data, editing data, business rules and built-in functionality, design configuration control and report generation. This course can be tailored to a specific plant’s dataset.

SAFE User Training


(Duration: 1 day) This course covers the use of the Genesis Solution Suite® SAFE module for ensuring post fire reactor safety using deterministic, performance-based, or a combination of both safe shutdown analysis strategies.