Combustible Dust Testing

Laboratory testing to quantify dust explosion and reactivity hazards

Safety Data Sheets

Develop critical safety data for inclusion in SDS documents

Gas and Vapor

Laboratory testing to quantify explosion hazards for vapor and gas mixtures

Classification of hazardous materials subject to shipping and storage regulations
Testing and consulting on the explosion risks associated with devices and processes which use or produce hydrogen
Safety Data Sheets

Develop critical safety data for inclusion in SDS documents

Thermal Stability

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

Adiabatic Calorimetry
Data demonstrate the consequences of process upsets, such as failed equipment or improper procedures, and guide mitigation strategies including Emergency Relief System (ERS) design
Reaction Calorimetry
Data yield heat and gas removal requirements to control the desired process chemistry
Battery Safety

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

Safety Data Sheets

Develop critical safety data for inclusion in SDS documents

Cable Testing
Evaluate electrical cables to demonstrate reliability and identify defects or degradation
Equipment Qualification (EQ)
Testing and analysis to ensure that critical equipment will operate under adverse environmental conditions
Water Hammer
Analysis and testing to identify and prevent unwanted hydraulic pressure transients in process piping
Acoustic Vibration
Identify and eliminate potential sources of unwanted vibration in piping and structural systems
Gas & Air Intrusion
Analysis and testing to identify and prevent intrusion of gas or air in piping systems
ISO/IEC 17025:2017

Fauske & Associates fulfills the requirements of ISO/IEC 17025:2017 in the field of Testing

ISO 9001:2015
Fauske & Associates fulfills the requirements of ISO 9001:2015
Dust Hazards Analysis
Evaluate your process to identify combustible dust hazards and perform dust explosion testing
On-Site Risk Management
On-site safety studies can help identify explosibility and chemical reaction hazards so that appropriate testing, simulations, or calculations are identified to support safe scale up
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 safely handle the effluent discharge from an overpressure event

FATE™ & Facility Modeling

FATE (Facility Flow, Aerosol, Thermal, and Explosion) is a flexible, fast-running code developed and maintained by Fauske and Associates under an ASME NQA-1 compliant QA program.

Mechanical, Piping, and Electrical
Engineering and testing to support safe plant operations and develop solutions to problems in heat transfer, fluid, flow, and electric power systems
Hydrogen Safety
Testing and consulting on the explosion risks associated with devices and processes which use or produce hydrogen
Thermal Hydraulics
Testing and analysis to ensure that critical equipment will operate under adverse environmental conditions
Nuclear Safety
Our Nuclear Services Group is recognized for comprehensive evaluations to help commercial nuclear power plants operate efficiently and stay compliant
Radioactive Waste
Safety analysis to underpin decomissioning process at facilities which have produced or used radioactive nuclear materials
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.

Recent Posts

In-Vessel Retention (IVR) as a Severe Accident Management Strategy

Posted by Fauske & Associates on 05.17.17


During a rare accident involving severe core damage in a Nuclear Power Plant (NPP), if the molten core material can be contained within the boundary of the reactor vessel, the severity of the accident is expected to be greatly reduced. Therefore, the severe accident management strategy based on in-vessel retention (IVR) of molten core debris is highly desirable, and has been adopted by advanced reactor designs such as VVER, AP1000 and APR1400. In these designs, the IVR strategy requires NPP operators to perform specific actions including: a) Opening valves to depressurize the reactor vessel and reduce the stress in the reactor vessel lower head b) Flooding the reactor cavity to a certain high level to ensure the reactor vessel is covered and cooled by water from the outside c) Injecting water into the reactor vessel after the vessel is fully depressurized to increase the probability of IVR success One of advantages of the IVR strategy is that the actions required in this strategy can be performed without AC power.


Issues Related to IVR Success

Success of IVR depends on the heat flux from the molten core material (corium) to the reactor vessel wall. The heat flux must not exceed the mechanical and thermal limits that fail the vessel. The mechanical limit is due to the fact that the reactor vessel wall must be ablated to a very small thickness that allows the heat flux to be conducted through it. However, if the vessel wall is too thin, it is unable to support the corium in the lower head and the dead weight of the lower head wall. In this case, the vessel will creep to failure. The thermal limit is due to the fact that the heat flux must not exceed the critical heat flux (CHF) on the outer surface of the reactor vessel wall. If the heat flux exceeds the CHF, the reactor vessel wall temperature will increase rapidly and lead to failure.

The heat flux from the in-vessel corium to the reactor vessel is non-uniform along the vessel wall. It has been agreed among IVR researchers that the highest heat flux may occur at the top of the corium, where the metallic material in the corium pool is segregated from the heavier oxidic material to form a metal layer. The thinner the metal layer is, the larger the heat flux to the wall, resulting in so-called “focusing effect.” Ideally there would be a sufficient amount of metals including steel and unoxidized Zr to form a thick metal layer at the top. However, in certain conditions, unoxidized Zr in the corium can reduce UO2 in the corium to form U metal. The eutectic U, Zr and steel is heavier than the oxidic material and stays at the bottom of the corium to form a heavy metal layer. The heavy metal is postulated to remove the steel in the top (light) metal layer, making the light metal layer thinner and the “focusing effect” worse.


Capabilities of MAAP5 Code for IVR Analysis Application

IVR analysis is challenging and, in many situations, requires simulations using integral a severe accident thermal hydraulic code. An appropriate code is the Modular Accident Analysis Program (MAAP), which is owned by the Electric Power Research Institute (EPRI) and developed and maintained by Fauske & Associates, LLC (FAI). The latest official revision of the MAAP5 code, MAAP5.03, is equipped with comprehensive models of the corium pool in the lower plenum, reactor vessel and in- and ex-vessel heat transfer. The key features of the models are discussed below. Page 1 Technical Bulletin No: N-16-07 In-Vessel Retention (IVR) as a Severe Accident Management Strategy By: Quan Zhou, Ph.D., Sr. Nuclear Engineer, Fauske & Associates, LLC

As shown in Figure 1(a), MAAP5 assumes that metallic material forms a light metal layer once the corium is present in the lower head. If the corium enters a water-flooded lower head, corium can be fragmented due to fuel coolant interaction (FCI). The fragmented frozen corium particles remain as a particle bed on top of the crust separating the metal layer and oxidic layer. As the particle bed is melted, the molten mass is added into the light metal layer and the oxidic layer, eventually leading to a two-layer model as shown in Figure 1(b). At certain conditions, a heavy metal layer can be formed in the lower portion of the oxidic layer, and the corium pool is then modeled as a three-layer structure as shown in Figure 1(c).

N-16-07 In-Vessel Retention (IVR) as a Severe Accident Management Strategy_Page_1.jpg


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