• EPM Inc.

    Framingham, MA
    Raleigh, NC

    +1 508-875-2121

EPM has hundreds of person-years of operating nuclear power plant experience, and much of that experience has been directly involved with the Probabilistic Risk Assessment of operating nuclear plants. For internal events PRA model development, our engineers have expertise in the areas of initiating events identification and quantification, accident sequence analysis, success criteria determination, systems modeling, data analysis and human reliability analysis using state-of-the-art technology. We have in-house expertise with modeling in WinNUPRA, CAFTA and SAPHIRE and in performing human reliability analysis using the EPRI HRA Calculator. Success criteria and HRA timing is typically performed using the MAAP severe accident analysis code, for which EPM has wide-ranging thermal-hydraulics modeling experience.

In order to ensure that the PRA modeling reflects the as-built, as-operated plant, EPM engineers are also available to validate the models by means of plant walkdowns, records reviews and by interviews with systems engineers and Operations personnel.

Because of our extensive experience with operating nuclear plants, EPM is also ideally suited for supporting various applications of risk information, including:

·   Mitigating Systems Performance Index margin improvement

·   Maintenance Rule Scope and Risk Significance

·   Maintenance Rule (a)(4) model development and evaluations

·   Risk Informed Licensing Application preparation

Fire PRA

The new regulatory environment encourages increasing the use of PRA technology in all regulatory matters. EPM’s Fire Probabilistic Risk Assessment (PRA) approach consists of an integrated assessment of the acceptability of risk, defense-in-depth, and safety margins. A Fire PRA is conducted by identifying fire scenarios that may affect the safe operation of the plant (through impacts on equipment and human actions) and estimating the frequency of occurrence of those scenarios. Transition to NFPA 805 allows for the use of fire risk evaluation (Fire PRA) to evaluate the effects of fire on the ability to achieve nuclear safety performance criteria.

EPM has the necessary resources and experience to perform a comprehensive Fire PRA.

Seismic PRA

EPM and our partners have the experience and qualifications to support a variety of seismic risk analyses for the nuclear industry.

Our engineers have a significant level of experience supporting both seismic and PRA analyses. Our seismic analysis team also offers complete support to clients for response to NRC seismic re-evaluation for recommendation 2.1 of the near-term task force review of insights from the Fukushima Dai-Ichi accident, including the following analyses:

·   Seismic Equipment List Development

·   Seismic Walk-down Support

·   Structure and Component Seismic Fragility Analysis

·   Seismic Plant Response Analysis, including:

·    Seismically-induced initiating events evaluation
·    Seismically-induced accident sequence evaluation
·    Structures, Systems and Components (SSC) failure evaluation (seismically- induced and non-seismically-induced)
·    Seismic correlation/dependency evaluation
·    Screening of high capacity SSCs
·    Relay chatter evaluation
·    Seismic Human Reliability Analysis (HRA) evaluation

·   Seismic PRA Quantification

·   Seismic Margins Analysis (EPRI or NRC method), including:

·    Review Level Earthquake (RLE) selection
·    Systems analysis and/or success path selection (methodology-specific)
·    Screening of high capacity SSCs
·    High-Confidence, Low Probability of Failure (HCLPF) evaluation for unscreened SSCs
·    Treatment of non-seismic failures and human actions
·    Evaluation of containment and containment systems (methodology-specific)
·    Relay chatter evaluation

·   Development of Alternatives for Reducing Seismic Risk

·   Peer Certification Review Support

·   NRC Request for Additional Information (RAI) Support

EPM can offer seismic analysis and risk assessment services to support and complement your facility’s engineering team at whatever level of involvement you require. In addition to seismic response support, our services can be customized to address your unique engineering needs through the development of specific engineering solutions for your particular facilities and circumstances.

Low Power & Shutdown PRA

EPM staff have experience developing risk assessments for shutdown conditions. A full scope low power and shutdown model can provide several potential benefits to a utility, including reduced conservatisms for 10 CFR 50.69 categorization, quantitative evaluations and reduced conservatisms of shutdown configuration risk assessments for 10 CFR 50.65 (a)(4), and quantitative assessment capability for transition and shutdown risk evaluations associated with Significance Determination Process, NOEDs, and Technical Specification changes. EPM staff are involved with the ASME/ANS standards development process, which includes industry and NRC development of the low power/shutdown standard ANS/ASME 58.22.

EPM can assist with all facets of Low Power/Shutdown model development, or shutdown risk assessments for specific purposes (not a full scope model) can also be supported.