Installation of FireSuppression in Gloveboxes Michael E. Cournoyer and Donivan R. Porterfield LAUR 12-20121
LANL Mission Is National Security• We develop and apply science and technology to – Ensure the safety and reliability of United States nuclear deterrent – Reduce the threat of weapons of mass destruction, proliferation, and terrorism; and – Solve national problems regarding defense, energy, environment, and infrastructure.
Typical Glovebox Train"
The Evolution• Both NFPA 801 and DOE Standard 1066, “Fire Protection Design Criteria”, require fire suppression to be installed in gloveboxes• During the design phase of a multi-station waste processing box we were tasked to provide recommendations for fire suppression system.
Other Suppression Systems• We looked at numerous fire suppression, or fire mitigation systems. – Water-based • Inexpensive to procure and install • Reliable • Generate large volume of water that may be difficult to dispose of • Loss of containment • Criticality issues
Other Suppression Systems• Dry Chemical – Expensive to procure and install – Reliable – Expansion of confinement boundary• Inertion – Expensive to procure and install – Reliable
Seismic Reliability• Water-based – Water supply may be affected by a seismic event• Dry Chemical – Storage cylinder and distribution piping may be compromised seismic event – Response time of the initiating device may be adversely affected by a seismic event• Inertion – Inerting may be compromised or lost in by a seismic event
Automatic Fire Extinguisher• Our efforts led us to an automatic clean agent fire extinguisher – U.L. Listed (U.L. 2166) for Class B and C fires
Envirogel Extinguishing Agent• Contents of fire extinguisher: – FE-25 & FE-36 – Sodium bicarbonate powder – Charged with an inert gas to 100 psi• Manufactures inquiries – Extinguisher is currently utilized for Class A applications – Confident fire test would prove extinguisher’s ability to successfully extinguish class A fires – U.L. 2166 Class A fire test enclosure volume ~3500 cu.ft.
Automatic Fire Extinguisher• Self contained and compact• Activated by temperature• Bolt-on simplicity• No mechanical, electrical, or battery systems required• Rugged construction and maintenance free• The extinguisher reacts to all fires• Installation and orientation• Volume protected
Automatic Fire Extinguisher• Extinguisher is vibration and corrosion resistant• UL approved for 130 cu.ft. enclosures and NRTL Certified for 250 cu.ft. enclosures• Airflow• Automatic Extinguisher – Extinguisher not affected by a seismic event – Redundancy of extinguishers would yield an extinguisher at the top of the glovebox
Operational Impact• Cleanup is simple and yield significantly less waste than water based fire suppression systems• Minimizes environmental impact• Return to service
Test Protocol• Lack of industry standard fire test• Test Protocol – Structured for our application
Collaboration with UT"• Collaborated with the Mechanical Engineering Department of the University of Texas at Austin continues• This effort is lead by Professor Sheldon Landsberger and Ofodike A. Ezekoye
Experiments"• Alpha experiments - Curium Source – 10 microcuries on 3/1/98 – 18.11 year half-life – 5 mm active area diameter• Neutron experiments – Irradiation 4+ months of glove samples – Tensile testing• More neutron experiments – 5 Ci PuBe homogeneous neutron source – Duration: 2 months
Fire Modeling While LANL glovebox systems are designed and operated with fire safety goals in mind, suppression systems that meet strict reliability requirements are integral parts of the overall fire protection system for these systems. Our project goal is to use calibrated and validated fire and mechanical modeling tools to understand the operating characteristics of the QuickFire Fire Foe suppression system for gloveboxes.http://www.quick-fire.com/products-01.asp
Small-Scale Filled Nylon-6 Tube Experiments
Development of Computational ModelSchematic of small-scale FDS Gas temperature slice in geometry setup small-scale FDS glovebox
Heat Release Rate CharacterizationA fire of unknown size occurs… The compartment is instrumented with thermocouples. What HRR Temperature would cause those temperature profiles? Time We use inversion.
Model Calibration to Experiment Experimental thermocouple Gas temperaturetemperatures compared slice in small-scale to FDS thermocouple FDS glovebox temperatures in the small-scale experiment
Analytical Heat Transfer Model• Fire Foe is modeled as a cylinder under constant, uniform radiative heat flux.• Forced convection with constant heat transfer coefficient.• Specific heat and density do not vary with temperature.
CFD Prediction of Heat FluxTime sequence of net heat flux of Fire Foe tube in the small-scale case
Finite Element Analysis Tools• SolidWorks Software – Finite element analysis of Nylon 6-6 tube• LibMesh – Open-source finite element solver
Simulations• Variables – Size of glove box – Intensity of fire – Location of fire suppression system – Location of vent hood – Location of glass• Results – Is the Fire Foe system reliable for all cases? – Optimal location for Fire Foe system – Worst-case scenario
Testing Results Summary• This result shows that even at a relatively low internal temperature of approximately 150 °C, the internal pressure and the relative loss of strength of the PA66 will likely result in failure of the tube.• As more detailed modeling of the PA66 failure process takes place, we will use data from Kohan on the elongation (%) at break and at yield for PA66. Kohan presents data at 23 °C and 77 °C for tensile strength, tensile yield strength, elongation at break, and elongation at yield.
Collaboration with MSU"• Collaborated with the Mechanical Engineering Department of the Montana State University.• This effort is lead by Professor David A. Miller
Tensile Testing"• Test Resources 1000R tensile testing machine was used to evaluate mechanical properties.• Maximum stress and strain are reported from industry standard tensile test - ASTM 1708
Summary• The extinguisher has been independently certified to successfully extinguish Class A, B, and C fires, based on LANL test criteria.• The extinguisher presents the most reliable means of suppression in a post seismic event• Installation of the extinguisher will satisfy DOE and NFPA requirements for automatic fire suppression in gloveboxes.• A computational fire model is being developed to predict fire extinguisher activation time for a wide range of fire inputs and glovebox configurations.• Any questions?
Acknowledgements"• The authors would like to acknowledge the Department of Energy and LANLs Plutonium Science & Manufacturing; Chemistry, Life, and Earth Sciences; Engineering and Engineering Sciences; and Nuclear & High Hazard Operations Directorates, for support of this work.