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

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

UN-DOT

Classification of hazardous materials subject to shipping and storage regulations

Safety Data Sheets

Develop critical safety data for inclusion in SDS documents

Biological

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

Radioactive

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

FERST

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

FATE

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

Blog

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.

Resources

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

Published December 18, 2018

Safe Packaging of Chemically Reactive Radioactive Waste

James P. Burelbach, PhD, Elizabeth J. Raines and Martin G. Plys, ScD, Fauske & Associates, LLC

INTRODUCTION

Fauske-&-Associates,-LLC-Test-Cell-1In the chemical process industry bench-scale thermal hazard testing is an effective approach to quickly collect critical safety data for process scale-up and management of change.

These accepted test methods are directly relevant to the packaging, transport, and storage of radioactive waste that is or can become chemically reactive.

For chemically reactive waste streams it is vital to identify safe temperature and pressure conditions and to quantify adiabatic heat and gas generation rates in order prevent or accommodate thermal instability within the waste package or storage facility.

ORGANIC-NITRATE EXPERIMENTS (ARSST)

High level waste streams can include organic-bearing sludge and salt cake waste. Organic complexants like sodium acetate along with oxidizers like sodium nitrate present the potential for spontaneous runaway chemical reactions (thermal instability).

The data below are for 20.5% sodium acetate (6% Total Organic Carbon, or TOC) in a simulant oxidizer mixture heated at 1 °C/min. These data show significant exothermic activity at 200 °C with “ignition” at 300 °C.

chemical reactive waste   runaway chemical reactions

Ammonium nitrate is another common oxidizer that has been involved in large scale industrial disasters and is potentially explosive when mixed with organic fuel.  The data below illustrate the effect of a small amount of organic contamination (polyethylene scrap).

large scale industrial disaster

ADIABATIC CALORIMETRY  TOOLSVent sizing package 2

VSP2™ (Vent Sizing Package 2)

  • Up to 100 ml sample size
  • Stainless, Hastelloy, or glass-lined test cells
  • Pressure balancing
  • Closed cell testing gives direct vapor pressure
  • Strong mixing suitable for two-phase or slurries
  • Scale suitable for contamination studies
  • Scale suitable for in-test dosing or sampling
  • Test setup takes about 2 hrs

COMMON FEATURES

  • Test solids or liquids (magnetic stirring)
  • Light-weight test cell à low thermal inertia
  • Test cell heat capacity << sample heat capacity
  • “Phi-factor” ϕ close to unity ~ 1.05 to 1.1
Phi Factor testing
  • Evolved heat is not lost to the container (or the environment) but increases the sample temperature

COMMON  BENEFITS

  • Data are directly scalable
  • Measure adiabatic temperature rise (ATR)
  • Measure temperature rise rate dT/dt = f(T)scalable tempurature data
  • Measure pressure rise rate dP/dt = f(T)
  • Infer molar gas generation rate
  • Kinetic modeling

COMMON APPLICATIONS

  • Emergency vent sizing (pressure relief)
  • Safe storage temperature
  • Safe package/container size
  • Time to maximum rate (TMR)
  • Temperature of no return (TNR)
  • Self-accelerating decomposition temperature (SADT)

ARSST™ (Advanced Reactive System Screening Tool)advanced reactive system screening tool

  • Up to 10 ml sample size
  • Scale suitable for thermal screening (identify energetic reactions)
  • Normally open cell testing
  • Scale suitable for large rates of gas generation (decomposition)
  • Scale suitable for operation in a glove box or hot cell
  • Test setup takes about 20 min

 

“RED OIL” EXPERIMENTS (VSP2)

Tri-n-butyl phosphate (TBP) saturated with concentrated nitric acid (HNO3) can form two-layer organic/aqueous morphology in  solvent extraction system evaporators and tanks.  The organic phase reacts exothermically and under certain conditions this can lead to a thermal runaway

(e.g. Tomsk-7 reprocessing plant explosion in Russia, 1993).

Red Oil Experiment Red Oil Temperature Red Oil Self Heat Rate Red Oil Self Heat Rate experiment

CONCLUSIONS

ORGANIC-NITRATE EXPERIMENTS

  • Organic contamination in an oxidizer such as sodium nitrate or ammonium nitrate can lead to an Arrhenius runaway reaction followed by a wave-like “propagating reaction”
  • Thermal hazard testing can identify the minimum TOC required for a reaction to propagate, and the observed kinetics provide a technical basis for safe packaging and storage

RED OIL EXPERIMENTS

Two separate exotherms were observed

  • The 1st exotherm at 80 °C is mild (< 1 °C/min)Test cell heat rates
  • Tempering (under atmospheric pressure) occurs at about 100 °C due to evaporation of dissolved water
  • The 2nd exotherm (two peaks) is stronger (< 10 °C/min)
  • Peak rates are reduced for lower HNO3 concentrations or in the presence of decomposition products (e.g. butyl nitrate) but the activation energy (inferred from the dT/dt slope) is unchanged
  • In a “closed cell” configuration (e.g. if the process vessel vent is closed or plugged) tempering does not occur and pressure builds
  • Closed cell self-heat rates increase exponentially to 1000 °C/min
  • The Tomsk-7 accident can be explained by a combination of weak tempering and insufficient venting capacity

Containment Vessels

REFERENCES

Burelbach, J. P., & Theis, A. E. (2005). “Thermal Hazards Evaluation using the ARSST,” 3rd Intl. Symposium On Runaway Reactions, Pressure Relief Design, and Effluent Handling, Cincinnati.

Epstein, M., et al. (2008). “Thermal Stability and Safe Venting of the Tri-n-Butyl Phosphate-Nitric Acid-Water (‘Red Oil’) System—II: Experimental Data on Reaction Self-Heat Rates and Gas Production and their Correlation,” Vol. 163, Nuclear Technology, Aug. Ibid, “III: Predictions of Thermal Stability Boundaries and Required Vent Size.”

 Subscribe to Blog

Sign up for our newsletter to Get all the latest information

Share this article

Find more resources articles

OR
RESET