Hazards Analysis, Code Compliance & Procedure Development

Services to identify process safety hazards and facilitate compliance with established standards and codes.

Combustible Dust Testing

Laboratory testing to quantify dust explosion and reactivity hazards

Flammable Gas & Vapor Testing

Laboratory testing to quantify explosion hazards for vapor and gas mixtures

Chemical Reactivity Testing

Laboratory testing to quantify reactive chemical hazards, including the possibility of material incompatibility, instability, and runaway chemical reactions

DIERS Methodology

Design emergency pressure relief systems to mitigate the consequences of unwanted chemical reactivity and account for two-phase flow using the right tools and methods

Deflagrations (Dust/Vapor/Gas)

Properly size pressure relief vents to protect your processes from dust, vapor, and gas explosions

Effluent Handling

Pressure relief sizing is just the first step and it is critical to safety handle the effluent discharge from an overpressure event

Thermal Stability

Safe storage or processing requires an understanding of the possible hazards associated with sensitivity to variations in temperature


Classification of hazardous materials subject to shipping and storage regulations

Safety Data Sheets

Develop critical safety data for inclusion in SDS documents


Model transport of airborne virus aerosols to guide safe operations and ventilation upgrades


Model transport of contamination for source term and leak path factor analysis

Fire Analysis

Model transport of heat and smoke for fire analysis

Flammable or Toxic Gas

transport of flammable or toxic gas during a process upset

OSS consulting, adiabatic & reaction calorimetry and consulting

Onsite safety studies can help identify explosibility and chemical reaction hazards so that appropriate testing, simulations, or calculations are identified to support safe scale up

Mechanical, Piping, and Electrical

Engineering and testing to support safe plant operations and develop solutions to problems in heat transfer, fluid flow, electric power systems

Battery Safety

Testing to support safe design of batteries and electrical power backup facilities particularly to satisfy UL9540a ed.4

Hydrogen Safety

Testing and consulting on the explosion risks associated with devices and processes which use or produce hydrogen

Spent Fuel

Safety analysis for packaging, transport, and storage of spent nuclear fuel

Decommissioning, Decontamination and Remediation (DD&R)

Safety analysis to underpin decommissioning process at facilities which have produced or used radioactive nuclear materials

Laboratory Testing & Software Capabilities

Bespoke testing and modeling services to validate analysis of DD&R processes

Nuclear Overview

Our Nuclear Services Group is recognized for comprehensive evaluations to help commercial nuclear power plants operate efficiently and stay compliant.

Severe Accident Analysis and Risk Assessment

Expert analysis of possible risk and consequences from nuclear plant accidents

Thermal Hydraulics

Testing and analysis to ensure that critical equipment will operate under adverse environmental conditions

Environmental Qualification (EQ) and Equipment Survivability (ES)

Testing and analysis to ensure that critical equipment will operate under adverse environmental conditions

Laboratory Testing & Software Capabilities

Testing and modeling services to support resolution of emergent safety issues at a power plant

Adiabatic Safety Calorimeters (ARSST and VSP2)

Low thermal inertial adiabatic calorimeters specially designed to provide directly scalable data that are critical to safe process design

Other Lab Equipment and Parts for the DSC/ARC/ARSST/VSP2 Calorimeters

Products and equipment for the process safety or process development laboratory


Software for emergency relief system design to ensure safe processing of reactive chemicals, including consideration of two-phase flow and runaway chemical reactions


Facility modeling software mechanistically tracks transport of heat, gasses, vapors, and aerosols for safety analysis of multi-room facilities


Our highly experienced team keeps you up-to-date on the latest process safety developments.

Process Safety Newsletter

Stay informed with our quarterly Process Safety Newsletters sharing topical articles and practical advice.


With over 40 years of industry expertise, we have a wealth of process safety knowledge to share.

Published November 5, 2014

MARS – A Powerful Severe Accident Modeling Tool for 27 Years

By Nick Karancevic, Sr. Nuclear Engineer, Fauske & Associates, LLC 

When one hears reference to Mars, the mind often travels to thoughts of the second smallest planet in our solar system.  Fauske & Associates, LLC (FAI) has a Mars of its own – but it isn’t a planet.  In this case, the Modular Accident Response System (MARSTM)  is a unique software suite designed to assist with nuclear power related severe accident analysis. 

First introduced in 1987, MARSTM was developed by FAI as an engineering tool to monitor and predict potential future states of nuclear power plants under either abnormal, or accident conditions.  It uses dynamic sets of plant data to initialize the highly benchmarked, world class thermal-hydraulics Modular Accident Analysis Program (MAAP) software to track plant data and to perform multiple faster than clock time predictions of potential plant response as a result of projected hazardous conditions.  MAAP is a product of the Electric Power Research Institute (EPRI), developed and maintained by FAI.
MARS Intro Presentation 5

Understanding the consequences of abnormal and severe accidents in the nuclear power industry has always been a critical part of maintaining safe and effective operations. The importance of understanding potential consequences was brought front and center in the aftermath of the 2011 Fukushima Daiichi Nuclear Power Plant event.  

The highly customizable nature of the MARS software makes it a useful tool for utilities to perform very specific analysis of potential scenarios. MARS is a versatile software, able to operate online (i.e. connected to a plant process computer), or offline.  In online mode, it gathers information from the plant process computer to obtain a view of plant conditions, including temperatures, pressures, and water levels, throughout the primary, secondary, and containment systems.  The software has two key functions: tracking and predicting.

The MARStracker can initialize a plant simulation at any time using a limited set of dynamic plant data.  Once initialized, it provides detailed real-time information about the current plant state, including the ability to evaluate and monitor specific plant parameters, such as fuel status, system status, and hydrogen concentrations.

MARS predictors perform multiple faster than real-time predictions of potential plant states based upon the current understanding of plant conditions.  These predictions can improve response time during an actual event, and provide valuable insight regarding whether it is better to shelter, or to evacuate.  It can also model operator actions and plant accident management procedures, and it can address uncertainties with model assumptions. 

A more detailed list of the features of the software include:

  • Solid engineering simulations of nuclear power plants based on the industry leading MAAP code
  • Ability to use “live” online plant data for engineering simulations and/or offline data
  • Software simulation models to represent operator actions in accordance with plant procedures
  • User-friendly graphical user interface representing the nuclear power plant
  • Engineering models for emergency response activities (for example, off-site radiation dose assessment) 

MARSTM can provide:

  • Accident management support
    • Offers educated, faster than real time response predictions during emergencies
  • Instrumentation verification
    • Tracks plant data to simulate plant instrumentation readings and therefore provide verification of instrumentation readings
  • Emergency Preparedness/Drill Development and Scenarios
    • Estimates timing and magnitude of possible releases of radiation
    • Provides dynamic interactive simulations allowing participant input
  • Plant Monitoring
    • Offers engineering evaluations of the plant response
    • Assesses when procedural limits (at power or shutdown) could be exceeded
  • Reactor accident response training simulations
    • Accurately represents the plant status during accident conditions 

MARS undergoes extensive testing prior to its release to a customer.  The testing involves using real plant accident data along with computer simulations of potential accident conditions.   The MARS software is then initialized and tracks the evolving plant data during key points of those real or simulated scenarios. The MARS results are then compared the actual or simulated data to establish confidence in the tool.  MARS development is considered complete when the results generated by MARS and actual/simulated data are consistent.

As you can see, with a solid 27 years of experience, MARS is a very relevant and powerful engineering tool that can be used to assist in the emergency response to a severe accident, or aid in mitigation of upset conditions through engineering simulation.  

For more information regarding MARSTM and other severe accident analysis, contact Nick Karancevic at (630) 323-8750 or Karancevic@fauske.com

Subscribe to FAI's "Nuclear Technical Bulletins"


Sign up for our newsletter to Get all the latest information

Share this article

Find more resources articles