Electromagnetic seal for the impulse feeding of gases into vacuum apparatuses

International Nuclear Information System (INIS)

Derevyankin, G.E.; Dudnikov, V.G.; Zhuravlyov, P.A.

The construction of an electromagnetic seal for the impulse feeding of gases into vacuum systems is described. The seal feeds small bursts of gas into an evacuated chamber at frequencies up to 10 3 Hz. The long lifetime of the seal (more than 10 9 cycles) results from the elimination of stressed metallic components and the use of ''Viton'' for the vacuum gasket under the valve

40 CFR Appendix B to Part 61 - Test Methods

Science.gov (United States)

2010-07-01

... impinger to the nearest 0.5 g. 8.3.2Install the selected nozzle using a Viton A O-ring when stack... standards. 11.0Analytical Procedure 11.1Sample Loss Check. Check the liquid level in each container to see... for metric units. K1 = 17.64 °R/in. Hg for English units. K3 = 10−6 g/µg for metric units. = 2.2046...

The Effect of Switch-Loading Fuels on Fuel-Wetted Elastomers

Science.gov (United States)

2007-01-10

material and age of the material”. In summing up past experience, the bulletin stated that “the common denominator is expected to be nitrile rubber ...The expert also noted that “most, if not all manufacturers, responded by eliminating nitrile rubber seals and replacing them with fluorocarbon...materials identified as from the Acrylonitrile- 4 Viton is a name trademarked by DuPont Performance Elastomers L.L.C. Butadiene family (nitrile, NBR

MWTF jumper connector integral seal block development and leak testing

International Nuclear Information System (INIS)

Ruff, E.S.; Jordan, S.R.

1995-01-01

In fiscal year 1993, tests of an o-ring/tetraseal retainer designed to replace a gasket-type seal used in PUREX-type process jumper connectors encouraged the design of an improved seal block. This new seal block combines several parts into one unitized component called an integral seal block. This report summarizes development and leak testing of the new integral seal block. The integral seal block uses a standard o-ring nested in a groove to accomplish leak tightness. This seal block eliminates the need to machine acme threads into the lower skirt casting and seal retainers, eliminates tolerance stack-up, reduces parts inventory, and eliminates an unnecessary leak path in the jumper connector assembly. This report also includes test data on various types of o-ring materials subjected to heat and pressure. Materials tested included Viton, Kalrez, and fluorosilicone, with some incidental data on teflon coated silicone o-rings. Test experience clearly demonstrates the need to test each seal material for temperature and pressure in its intended application. Some materials advertised as being open-quotes betterclose quotes at higher temperatures did not perform up to expectations. Inspection of the fluorosilicone and Kalrez seals after thermal testing indicates that they are much more susceptible to heat softening than Viton

Behaviour of fluoropolymers in presence of tritiated water

International Nuclear Information System (INIS)

Bubueanu, Gh.; Postolache, C.; Tuta, C.

2011-01-01

Complete text of publication follows. One of the most used methods for tritium recovery from tritiated water relies on combined electrolysis with catalytic isotope exchange techniques. The electrolytic cell converts the tritiated water or tritiated heavy water into a hydrogen, deuterium and tritium mixture. The mixture is purified and then tritium is recovered by catalytic isotopic separation techniques. Tritium presence in the system induces an intense radiation field especially at aqueous solution interface. This can generate significant structural modifications with potentially negative effects. In this paper work it is followed the study of radiolytic phenomena in Pt/C/PTFE isotopic exchange catalyst, NAFION membranes and VITON fluoroelastomer in presence of tritiated water with high radioactive concentration. Radiolytical processes were analyzed by: Exposure of fluoropolymers samples immersed in H 2 O at gamma radiation field (60-Co source) in vacuum, at liq. Nitrogen temperature and at ambient temperature respectively; Immersing of NAFION, Pt/C/PTFE catalyst and VITON samples in tritiated water with high activity (3.7 and 37 TBq/L) for different time period. In both cases the samples were characterized by FT IR ATR, and fluoride ions emission from polymeric matrix. Experimental results were correlated with quantum-chemical simulations.

Development of procedures for calculating stiffness and damping of elastomers in engineering applications, part 7

Science.gov (United States)

Rieger, A.; Zorzi, E.

1980-01-01

An elastomer shear damper was designed, tested, and compared with the performance of the T 55 power turbine supported on the production engine roller bearing support. The Viton 70 shear damper was designed so that the elastomer damper could be interchanged with the production T 55 power turbine roller bearing support. The results show that the elastomer sheer dampener permitted stable operation of the power turbine to the maximum operating speed of 16,000 rpm.

Electro-Static Discharge (ESD) Sensitivity of Reactive Powders and its Mitigation

Science.gov (United States)

2016-03-16

Al+CuO and Al+Bi2O3 by combining them with Viton A and guar gum , respectively [70, 71]. Similarly reduced ESD sensitivity resulted for the thermite...SECURITY CLASSIFICATION OF: This work followed our previous study characterizing ignition of pure metal powders by electrostatic discharge. Here, the...that ignition event for all materials can be described using two stages. First, a fraction of the powder struck by the spark is ignited directly

STIR: Investigation of Piezoelectric Reactives as Tunable Energetics for Advanced Munitions

Science.gov (United States)

2016-08-15

to the formation of α-AlF3. The lower adiabatic flame temperature for Al/Viton is due to its higher heat of formation and low enthalpy compensation...it may also be of practical interest to force quicker evaporation of the solvent at elevated temperatures. Propanone and butanone have high vapor ...conditions due to its low vapor pressure; such a time may be reduced by placing the drying composite in an elevated temperature environment (below the

Improvements for rotary viscous dampers used in spacecraft deployment mechanisms

Science.gov (United States)

Stewart, Alphonso; Powers, Charles; Lyons, Ron

1998-01-01

During component level thermal-vacuum deployment testing of eight rotary viscous dampers for the Tropical Rainfall Measuring Mission (TRMM) satellite, all the dampers failed to provide damping during a region of the deployment. Radiographic examination showed that air in the damping fluid caused the undamped motion when the dampers were operated in a vacuum environment. Improvements in the procedure used to fill the dampers with damping fluid, the installation of a Viton vacuum seal in the damper cover, and improved screening techniques eliminated the problem.

Optically pumped polarized alkali atomic beams and targets

International Nuclear Information System (INIS)

Anderson, L.W.

1984-01-01

The optical pumping of 23 Na and 6 Li atomic beams is discussed. Experiments on the optical pumping of 23 Na atomic beams using either a single mode dye laser followed by a double passed acousto-optic modulator or a multimode dye laser are reported. The optical pumping of a 23 Na vapor target for use in a polarized H - ion source is discussed. Results on the use of viton as a wall coating with a long relaxation time are reported. 31 references, 6 figures, 3 tables

Permeability measurement of some barrier materials as a function of temperature and pressure

International Nuclear Information System (INIS)

Maqsood, M.; Faisal, S.; Ali, J.; Usman, A.; Alamgir, K.; Farooq, K.

2011-01-01

Barrier materials possess the ability to restrict the passage of gases, vapors, and organic liquids through their boundaries. These barrier materials have large number of applications in industry and scientific research. To measure the permeability of barrier materials, a specific gas flow system has been developed, pure helium gas is used to measure the back ground reading through SS-316. The permeability and break-through time has been measured through Inconel X-750, NBR and Viton below and above the atmospheric pressure and at different temperatures 20 deg. C, 40 deg. C and 70 deg. C. (author)

Permeation of gasoline, diesel, bioethanol (E85), and biodiesel (B20) fuels through six glove materials.

Science.gov (United States)

Chin, Jo-Yu; Batterman, Stuart A

2010-07-01

Biofuels and conventional fuels differ in terms of their evaporation rates, permeation rates, and exhaust emissions, which can alter exposures of workers, especially those in the fuel refining and distribution industries. This study investigated the permeation of biofuels (bioethanol 85%, biodiesel 20%) and conventional petroleum fuels (gasoline and diesel) through gloves used in occupational settings (neoprene, nitrile, and Viton) and laboratories (latex, nitrile, and vinyl), as well as a standard reference material (neoprene sheet). Permeation rates and breakthrough times were measured using the American Society for Testing and Materials F739-99 protocol, and fuel and permeant compositions were measured by gas chromatography/mass spectrometry. In addition, we estimated exposures for three occupational scenarios and recommend chemical protective clothing suitable for use with motor fuels. Permeation rates and breakthrough times depended on the fuel-glove combination. Gasoline had the highest permeation rate among the four fuels. Bioethanol (85%) had breakthrough times that were two to three times longer than gasoline through neoprene, nitrile Sol-Vex, and the standard reference materials. Breakthrough times for biodiesel (20%) were slightly shorter than for diesel for the latex, vinyl, nitrile examination, and the standard neoprene materials. The composition of permeants differed from neat fuels, e.g., permeants were significantly enriched in the lighter aromatics including benzene. Viton was the best choice among the tested materials for the four fuels tested. Among the scenarios, fuel truck drivers had the highest uptake via inhalation based on the personal measurements available in the literature, and gasoline station attendants had highest uptake via dermal exposure if gloves were not worn. Appropriate selection and use of gloves can protect workers from dermal exposures; however, current recommendations from the National Institute for Occupational Safety and

Chemical compatibility screening test results

International Nuclear Information System (INIS)

Nigrey, P.J.; Dickens, T.G.

1997-12-01

A program for evaluating packaging components that may be used in transporting mixed-waste forms has been developed and the first phase has been completed. This effort involved the screening of ten plastic materials in four simulant mixed-waste types. These plastics were butadiene-acrylonitrile copolymer rubber, cross-linked polyethylene (XLPE), epichlorohydrin rubber, ethylene-propylene rubber (EPDM), fluorocarbon (Viton or Kel-F), polytetrafluoroethylene, high-density polyethylene (HDPE), isobutylene-isoprene copolymer rubber (butyl), polypropylene, and styrene-butadiene rubber (SBR). The selected simulant mixed wastes were (1) an aqueous alkaline mixture of sodium nitrate and sodium nitrite; (2) a chlorinated hydrocarbon mixture; (3) a simulant liquid scintillation fluid; and (4) a mixture of ketones. The testing protocol involved exposing the respective materials to 286,000 rads of gamma radiation followed by 14-day exposures to the waste types at 60 degrees C. The seal materials were tested using vapor transport rate (VTR) measurements while the liner materials were tested using specific gravity as a metric. For these tests, a screening criterion of 0.9 g/hr/m 2 for VTR and a specific gravity change of 10% was used. Based on this work, it was concluded that while all seal materials passed exposure to the aqueous simulant mixed waste, EPDM and SBR had the lowest VTRs. In the chlorinated hydrocarbon simulant mixed waste, only Viton passed the screening tests. In both the simulant scintillation fluid mixed waste and the ketone mixture simulant mixed waste, none of the seal materials met the screening criteria. For specific gravity testing of liner materials, the data showed that while all materials with the exception of polypropylene passed the screening criteria, Kel-F, HDPE, and XLPE offered the greatest resistance to the combination of radiation and chemicals

Mechanical behavior of fluoroelastomer considering long term ageing

Energy Technology Data Exchange (ETDEWEB)

Sinha, N.K., E-mail: nksinha@igcar.gov.in [Indira Gandhi Centre for Atomic Research (IGCAR), Department of Atomic Energy (DAE), Kalpakkam, Tamilnadu 603102 (India); Mukhopadhyay, R., E-mail: rm@ktp.jkmail.com [Hari Shankar Singhania Elastomer and Tyre Research Institute (HASETRI), J. K. Tyre and Industries Ltd., Kankroli, Rajasthan 313342 (India); Raj, Baldev, E-mail: dr.baldev@psg.org.in [Indira Gandhi Centre for Atomic Research (IGCAR), Department of Atomic Energy (DAE), Kalpakkam, Tamilnadu 603102 (India)

2013-01-15

Highlights: Black-Right-Pointing-Pointer Tensile stress-strain of aged (32 weeks; 140/170/200 Degree-Sign C) Viton A-401C specimens at RT, 110 Degree-Sign C. Black-Right-Pointing-Pointer Stress-softening negligible at 50/500 mm/min and RT/110 Degree-Sign C because of low black filler. Black-Right-Pointing-Pointer RT relaxation at lower strain rate; 110 Degree-Sign C curve stiffening from Joule-Gough effect. Black-Right-Pointing-Pointer Two zone stress-elongation behavior (cross-link, ionic domains) proposed. Black-Right-Pointing-Pointer Extendable to peroxide cured fluoroelastomers with Iodine at mid and end of chains. - Abstract: Stress-elongation behavior of a Viton A-401C based compound established for backup seals of 500 MW(e), Prototype Fast Breeder Reactor is depicted. Stress-softening effects are negligible during room temperature (RT) or 110 Degree-Sign C measurements on unaged samples at strain rates of 50 mm/min and 500 mm/min because of low filler content. Relaxation is observed during RT property determination at lower strain rate. Stiffening of behavior at 50 mm/min and 110 Degree-Sign C is attributed to Joule-Gough effect and absence of relaxation because of increased molecular chain mobility. The two zone stress-elongation behavior (determined by chemical cross-links up to {approx}85% strain and by ionic interactions beyond) propounded in the article by combining air-aged specimen data (32 weeks at 140/170/200 Degree-Sign C) provides a behavior map of bisphenol cured, low filler, fluoroelastomers made of vinylidene fluoride and hexafluoropropylene. This could be extended to peroxide cured fluorocarbon rubbers for verifications and providing qualified compounds of better grades for critical nuclear elastomeric sealing applications.

Improving the thermal properties of fluoroelastomer (Viton GF-600S using acidic surface modified carbon nanotube

Directory of Open Access Journals (Sweden)

Javad Heidarian

2015-08-01

Full Text Available AbstractAcid surface modified carbon nanotube (MCNT-, Carbon nanotube (CNT-filled fluoroelastomer (FE and unfilled-FE were prepared (MCNT/FE, CNT/FE and FE. The compounds were subjected to thermogravimetric analysis (TGA and heat air aging, and characterized by Energy Dispersive X-Ray (EDX. Results showed that MCNT improved the thermal properties of FE, resulting in a larger amount of FE and char remaining in the temperature range of 400-900 °C relative to unfilled FE and CNT/FE. The MCNT/FE TGA curve shifted towards higher temperatures compared to CNT/FE and FE. The same results also revealed that higher percentages of FE were undegraded or less degraded especially near MCNT in the temperature range of 400-540 °C. Energy Dispersive X-Ray (EDX results indicated that the percentage of carbon and fluorine in the residue of TGA scans, up to 560 °C, of MCNT/FE were the same as CNT/FE, and were higher than FE. EDX results of TGA residue (run up to 900 °C showed that most of the undegraded FE, which was not degraded at temperatures below 560 °C, was degraded from 560 °C to 900 °C in both MCNT/FE and CNT/FE, with the char in MCNT/FE being more than that in CNT/FE. EDX analysis of thermal aged specimens under air showed that, with increasing aging time, a greater percentage of C, O and F was lost from the surface of filler/FE and FE. The order of element loss after 24 hour aging time was: MCNT/FE > FE > CNT/FE.

Technical Review Report for the Model 9977 Safety Analysis Report for Packaging Addendum 1 Justification for DNDO Contents

Energy Technology Data Exchange (ETDEWEB)

West, M H

2008-12-17

The Model 9977 Package is currently certified for Content Envelope C.1, {sup 238}Pu Heat Sources, either in Radioisotope Thermoelectric Generator (RTG), or in Food-Pack Can configurations, under Certificate of Compliance (CoC) Certificate Number 9977 and Package Identification Number USA/9977/B(M)F-96 (DOE). Addendum 1, Justification for DNDO Contents,--the Submittal--supplements Revision 2 of the Safety Analysis Report for Packaging for the Model 9977 Package. The Submittal adds five new contents to the Model 9977 Package, Content Envelopes, AC.1 through AC.5. The Content Envelopes are neptunium metal, the beryllium-reflected plutonium ball (BeRP Ball), plutonium/uranium metal, plutonium/uranium metal with enhanced wt% {sup 240}Pu (to 50 wt%), and uranium metal. The last three Content Envelopes are stabilized to DOE-STD-3013. These Content Envelopes will be shipped to the Device Assembly Facility (DAF) at the Nevada Test Site (NTS), where they will reside, and, hence, to off-site locations in support of the Department of Homeland Security (DHS) Domestic Nuclear Detection Office (DNDO). The new certificate will apply to a limited number of Model 9977 Packages. At the same time, the Submittal requests an extension of the periodic maintenance requirements from one (1) year to up to five (5) years using Radio-Frequency Identification (RFID) temperature-monitoring systems to measure the ambient storage temperature in order to ensure that the temperature of the Viton{reg_sign} O-rings for the 6-inch Containment Vessel (6CV) remain less than 200 F. The RFIDs have been developed by Argonne National Laboratory. An on-going surveillance program at the K-Area Materials Storage (KAMS) facility at the Savannah River Site, and an on-going examination of Viton{reg_sign} O-rings from mock Primary Containment Vessels (PCVs) at Savannah River National Laboratory (SRNL) provide the technical justification for the extension of the periodic maintenance interval. Where extended

Optimization of material and production to develop fluoroelastomer inflatable seals for sodium cooled fast breeder reactor

Energy Technology Data Exchange (ETDEWEB)

Sinha, N.K., E-mail: nksinha@igcar.gov.i [Indira Gandhi Centre for Atomic Research (IGCAR), Department of Atomic Energy (DAE), Kalpakkam, Tamilnadu 603102 (India); Raj, Baldev, E-mail: dir@igcar.gov.i [Indira Gandhi Centre for Atomic Research (IGCAR), Department of Atomic Energy (DAE), Kalpakkam, Tamilnadu 603102 (India)

2011-03-15

Research highlights: Production of thin fluoroelastomer profiles by cold feed extrusion and continuous cure involving microwave and hot air heating. Use of peroxide curing in air during production. Use of fluoroelastomers based on advanced polymer architecture (APA) for the production of profiles. Use of the profiles in inflatable seals for critical application of Prototype Fast Breeder Reactor. Tailoring of material formulation by synchronized optimization of material and production technologies to ensure that the produced seal ensures significant gains in terms of performance and safety in reactor under synergistic influences of temperature, radiation, air and sodium aerosol. - Abstract: The feasibility of producing thin-walled fluoroelastomer profiles under continuous, atmospheric-pressure vulcanization conditions in air has been demonstrated by successful manufacture of {approx}2 m diameter test inflatable seals for the 500 MWe, Prototype Fast Breeder Reactor (PFBR) using a 50/50 blend formulation of Viton GBL-200S/600S based on advanced polymer architecture (APA). A commercial cold feed screw extruder with 90 mm diameter screw was used along with continuous cure by microwave (2.45 GHz) and hot air heating (190 {sup o}C) at a line speed of 1 m/min to produce the seals. The blend formulation promises significant improvement in the performance and safety of the seals. This article depicts the relevant characteristics of the original inflatable seal compound that was used as reference to achieve the objectives through synchronized optimization of material and production technologies. The production trials are outlined and the blend formulation used with minor factory modifications to produce the test seals is reported. Progressive refinements of the original, Viton A-401C based compound to the blend formulation is presented along with an assessment of potential performance gains. Possible uses of the reported formulation and production technique for other large

Optimization of material and production to develop fluoroelastomer inflatable seals for sodium cooled fast breeder reactor

International Nuclear Information System (INIS)

Sinha, N.K.; Raj, Baldev

2011-01-01

Research highlights: → Production of thin fluoroelastomer profiles by cold feed extrusion and continuous cure involving microwave and hot air heating. → Use of peroxide curing in air during production. → Use of fluoroelastomers based on advanced polymer architecture (APA) for the production of profiles. → Use of the profiles in inflatable seals for critical application of Prototype Fast Breeder Reactor. → Tailoring of material formulation by synchronized optimization of material and production technologies to ensure that the produced seal ensures significant gains in terms of performance and safety in reactor under synergistic influences of temperature, radiation, air and sodium aerosol. - Abstract: The feasibility of producing thin-walled fluoroelastomer profiles under continuous, atmospheric-pressure vulcanization conditions in air has been demonstrated by successful manufacture of ∼2 m diameter test inflatable seals for the 500 MWe, Prototype Fast Breeder Reactor (PFBR) using a 50/50 blend formulation of Viton GBL-200S/600S based on advanced polymer architecture (APA). A commercial cold feed screw extruder with 90 mm diameter screw was used along with continuous cure by microwave (2.45 GHz) and hot air heating (190 o C) at a line speed of 1 m/min to produce the seals. The blend formulation promises significant improvement in the performance and safety of the seals. This article depicts the relevant characteristics of the original inflatable seal compound that was used as reference to achieve the objectives through synchronized optimization of material and production technologies. The production trials are outlined and the blend formulation used with minor factory modifications to produce the test seals is reported. Progressive refinements of the original, Viton A-401C based compound to the blend formulation is presented along with an assessment of potential performance gains. Possible uses of the reported formulation and production technique for

Final report for Allied-Signal Aerospace Company, Kansas City Division on protective glove permeation analysis

International Nuclear Information System (INIS)

Swearengen, P.M.; Johnson, J.S.; Priante, S.J.

1990-01-01

We conducted 25 separate glove fabric permeation studies during this project. The permeations were carried out in the small (1 inch) glass ASTM cell. One other permeation study was carded out with a large (two inch) modified ASTM cell for comparison with the small cell results. We also compared the LLNL procedure from both large and small cells with the standard ASTM test procedure which uses a liquid solution on the breakthrough side of the fabric (the liquid is then sampled on a periodic basis). In all comparisons we observed a close-correlation in breakthrough times between the two procedures and the two cell sizes. In the course of this study, we tested ten different glove materials. These included neoprene (original ASTM round-robin sheet stock, 16 mil thickness), Edmont Sol-Vex (nitrile), Pioneer nitrile, Pioneer Pylox (polyvinyl chloride), North Viton (trademark for fluoroelastomers), North SilverShield (Norfoil, trademark for a flexible metallized laminate), Safety 4 4H (patented plastic laminate), and QRP PolyTuff (polyurethane) 20G-2000 (5 mil), 23G-2300 (1.5 mil), and 25G-2500 (1.5 mil). Three of the glove materials, Viton and Silver Shield (North), and 4H (Safety 4), did not allow any permeation measurable by our system to either 1,2-dichloroethane or 3% diphenylmercury (in 1,2-dichloroethane) for a period greater than six hours. A fourth material, QRP Poly Tuff 2OG-2000, did not allow any measurable penetration of Asilamine (an aromatic diamine) for a time pedod of greater than 4 hours. Breakthrough times and curves were obtained for all other tested materials. Eleven different chemicals were used to challenge the glove materials. These included acetone, Asilamine, 1,2-dichloroethane, dichloromethane, isopropyl alcohol, a mixture of 3% diphenylmercury in 1,2-dichloroethane (w/w), phenol, and lso Verre Stripper, 4,4'-methylenedianil (MDA), 1,3-phenylenediamine (MPDA), and Shell Epon (R) curing agent Z

Effects of gamma radiation on mechanical behavior of fluoropolymers/carbon nanotubes nanocomposites

International Nuclear Information System (INIS)

Pozenato, Cristina A.; Scagliusi, Sandra R.; Lugao, Ademar B.

2015-01-01

Fluoroelastomers are a elastomers group, which have excellent thermal and mechanical properties and high chemical resistance. They are used in environments to degrade most another polymers. Multiple polymers/carbon nanotubes nanocomposites are related in literature. The aim of this study was process and evaluates the changes in the mechanical properties due to the incorporation of functionalized carbon nanotubes in fluorinated rubbers. The nanocomposite was prepared from an open mill (Cope), with two rolls, with addition of carbon nanotubes of 1%, and Viton® from Dupont. The samples were subjected to gamma radiation using a 60 Co source with doses 5 kGy, 10 kGy, 20 kGy at room temperature and air atmosphere. The effects of incorporation were compared and evaluated. The characterization was made by tensile strength and elongation at break. (author)

Chemical degradation of fluoroelastomer in an alkaline environment

DEFF Research Database (Denmark)

Mitra, S.; Ghanbari-Siahkali, A.; Kingshott, P.

2004-01-01

We have investigated the time-dependent chemical degradation of a fluoroelastomer, FKM (Viton((R)) A), in an alkaline environment (10% NaOH, 80 degreesC). Optical microscopy and SEM analysis reveal that degradation starts with surface roughness right from the earliest stage of exposure (e.g., 1...... week) and finally results in cracks on the surface after prolonged exposure. Initially the extent of degradation is mainly confined to the surface regions (a few nanometers) but with longer exposure (e.g., 12 weeks) it extends to below the subsurface region of the fluoroelastomer. The extent...... of this surface degradation is found to be strong enough to affect the bulk mechanical properties. The molecular mechanisms of the surface chemical degradation were determined using surface analysis (XPS and ATR-FTIR) where the initial degradation was found to proceed via dehydrofluorination. This leads to double...

Limitations of ''margin'' in qualification tests

International Nuclear Information System (INIS)

Clough, R.L.; Gillen, K.T.

1984-01-01

We have carried out investigations of polymer radiation degradation behaviors which have brought to light a number of reasons why this concept of margin can break down. First of all, we have found that dose-rate effects vary greatly in magnitude. Thus, based on high dose-rate testing, poor materials with large dose-rate effects may be selected over better materials with small effects. Also, in certain cases, material properties have been found to level out (as with PVC) or reverse trend (as with buna-n) at high doses, so that ''margin'' may be ineffective, misleading, or counterproductive. For Viton, the material properties were found to change in opposite directions at high and low dose rates, making ''margin'' inappropriate. The underlying problem with the concept of ''margin'' is that differences in aging conditions can lead to fundamental differences in degradation mechanisms

Compatibility of selected elastomers with plutonium glovebox environment

International Nuclear Information System (INIS)

Burns, R.

1994-06-01

This illustrative test was undertaken as a result of on-going failure of elastomer components in plutonium gloveboxes. These failures represent one of the major sources of required maintenance to keep gloveboxes operational. In particular, it was observed that the introduction of high specific activity Pu-238 into a glovebox, otherwise contaminated with Pu-239, resulted in an inordinate failure of elastomer components. Desiring to keep replacement of elastomer components to a minimum, a decision to explore a few possible alternative elastomer candidates was undertaken and reported upon herewith. Sample specimens of Neoprene, Urethane, Viton, and Hypalon elastomeric formulations were obtained from the Bacter Rubber Company. Strips of the elastomer specimens were placed in a plutonium glovebox and outside of a glovebox, and were observed for a period of three years. Of the four types of elastomers, only Hypalon remained completely viable

Long-Term Leak Tightness Of O-Ring Seals In The 9975 Shipping Package

International Nuclear Information System (INIS)

Hoffman, E.; Skidmore, E.; Daugherty, W.

2010-01-01

O-ring seals in the 9975 shipping package containment vessels are fabricated from a Viton GLT or GLT-S compound. Long-term testing of these O-rings has been performed to support service life predictions for packages used for long-term storage. Since the only criterion for O-ring performance is to maintain a leak-tight seal, leak testing is the primary indicator of service life. Fixtures have been aging at elevated temperatures to provide data for service life predictions. Limited leak test failures have been observed at the higher temperatures. This provides the opportunity for comparison to trends based on other O-ring properties, such as compression stress relaxation. Initial data suggest that the CSR data have some predictive value for a leak-tight service life, but other factors can complicate efforts to draw definitive conclusions.

LX-04 VIOLENCE MEASUREMENTS- STEVEN TESTS IMPACTED BY PROJECTILES SHOT FROM A HOWITZER GUN

International Nuclear Information System (INIS)

Chidester, S K; Vandersall, K S; Switzer, L L; Tarver, C M

2005-01-01

Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton A by weight) was obtained from Steven Impact Tests performed above the reaction initiation threshold. A 155 mm Howitzer propellant driven gas gun was used to accelerate the Steven Test projectiles in the range of approximately 170-300 m/s to react (ignite) the LX-04 explosive. Blast overpressure gauges, acoustic microphones, and high-speed photography characterized the level of high explosive reaction violence. A detonation in this velocity range was not observed and when comparing these results (and the Susan test results) with that of other HMX based explosives, LX-04 has a more gradual reaction violence slope as the impact velocity increases. The high binder content (15%) of the LX-04 explosive is believed to be the key factor to the lower level of violence

Oxygen Compatibility of Brass-Filled PTFE Compared to Commonly Used Fluorinated Polymers for Oxygen Systems

Science.gov (United States)

Herald, Stephen D.; Frisby, Paul M.; Davis, Samuel Eddie

2009-01-01

Safe and reliable seal materials for high-pressure oxygen systems sometimes appear to be extinct species when sought out by oxygen systems designers. Materials that seal well are easy to find, but these materials are typically incompatible with oxygen, especially in cryogenic liquid form. This incompatibility can result in seals that leak, or much worse, seals that easily ignite and burn during use. Materials that are compatible with oxygen are easy to find, such as the long list of compatible metals, but these metallic materials are limiting as seal materials. A material that seals well and is oxygen compatible has been the big game in the designer's safari. Scientists at the Materials Combustion Research Facility (MCRF), part of NASA/Marshall Space Flight Center (MSFC), are constantly searching for better materials and processes to improve the safety of oxygen systems. One focus of this effort is improving the characteristics of polymers used in the presence of an oxygen enriched environment. Very few systems can be built which contain no polymeric materials; therefore, materials which have good impact resistance, low heat of combustion, high auto-ignition temperature and that maintain good mechanical properties are essential. The scientists and engineers at the Materials Combustion Research Facility, in cooperation with seal suppliers, are currently testing a new formulation of polytetrafluoroethylene (PTFE) with Brass filler. This Brass-filled PTFE is showing great promise as a seal and seat material for high pressure oxygen systems. Early research has demonstrated very encouraging results, which could rank this material as one of the best fluorinated polymers ever tested. This paper will compare the data obtained for Brass-filled PTFE with other fluorinated polymers, such as TFE-Teflon (PTFE) , Kel-F 81, Viton A, Viton A-500, Fluorel , and Algoflon . A similar metal filled fluorinated polymer, Salox-M , was tested in comparison to Brass-filled PTFE to

Eleventh interim status report: Model 9975 O-Ring fixture long-term leak performance

Energy Technology Data Exchange (ETDEWEB)

Daugherty, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-08-01

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperature. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF.

Vacuum system of the Tokamak Novillo

International Nuclear Information System (INIS)

Valencia Alvarado, R.; Lopez Callejas, R.; Melendez Lugo, L.; Chavez Alarcon, E.

1990-01-01

A toroidal vacuum chamber of 28 access ports was constructed from four stainless steel 316L elbows joined together with dielectric seals to provide voltage break in the toroidal direction. All vacuum seals were viton O-rings. A 500 1/s turbomolecular pump provide a base pressure of 4 x 10 -8 mbar with light backing (∼ 60 deg C). In the regime of cleaning discharge the toroidal chamber is filled with H 2 to a pressure of 0.2 + 0.4 mbar. The ohmic heating coils are pulsed with a AF oscillator (10 kW, 17.5 kHz) for 60-80 msec, at a repetition rate of about 2 Hz. A toroidal magnetic field of roughly 600 G is added to generate the cleaning discharge. According to a residual gas analyzer installed in the system, 80% of the base pressure was given by water; the other components were hydrogen and mon- and dioxides of carbon. (Author)

Narrativas para a gestão de mudanças: um estudo de caso na indústria vidreira

Directory of Open Access Journals (Sweden)

Valério Brusamolin

Full Text Available Este artigo propõe um modelo para análise do emprego de narrativas na gestão de mudanças, descrevendo os passos a serem seguidos e listando os padrões de histórias que podem auxiliar na gestão das transformações necessárias. O modelo é aplicado no estudo de caso da criação de uma empresa, a Viton Equipamentos para a Indústria Vidreira, do Grupo Wheaton Brasil, coletando as narrativas do gestor, classificando-as e analisando-as à luz do modelo proposto. Conclui-se que gerentes e outros contadores de histórias atuam como mediadores da informação, narrando histórias que transmitem a informação certa no momento oportuno, com efeitos transformadores positivos para a organização, produzindo mudanças cognitivas necessárias, transmitindo valores, cultura e auxiliando na percepção da realidade.

Effects of Laser Etching on the Corrosion Susceptibility of SAVY 4000 and Hagan Containers

Energy Technology Data Exchange (ETDEWEB)

Hyer, Holden Christopher [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Duque, Juan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Paul Herrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stroud, Mary Ann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-22

Since the late 1990’s, the Hagan container was used as the primary container for packaging of plutonium-bearing materials. The Hagan design consisted of a threaded closure, a Viton® ORing, a carbon-carbon filter, and a 304L stainless steel (SS) body. Over the years, Hagans have shown vulnerability in their design [1]. In 2008, The Department of Energy (DOE) issued DOE M 441.1-1, Nuclear Material Packaging Manual, which detailed an approach to obtain highconfidence in containers by including specific design requirements, material contents and an approach to determine life span from said contents, and surveillance techniques [2]. In response to both the vulnerability issues with the Hagan and DOE M 441.1-1, the SAVY 4000 container with its twist style closure, Viton® O-Ring, Fiberfrax-Gortex filter, and annealed 316L SS body, was designed as the replacement for Hagan containers, but only for a short term lifespan of 5 years [1]. However, both the Hagan and SAVY 4000 are being pushed to maintain a lifespan of 40 years. Therefore, proper confidence must be placed on each component of each container to last a minimum of 40 years. So far, the biggest concern found during surveillance of these containers is corrosion and the potential for failure by corrosion. One concern is that the containers fail due to stress corrosion cracking (SCC), especially around the weld between the collar and the body as welds leave residual stresses. One advantage the SAVY 4000 has is that the body is annealed, but its weld is still susceptible as it was welded after annealing [3, 4]. Moreover, 316L SS is known to have a higher pitting resistance (pits are a precursor to SCC and can also lead to extensive failure of the material), than 304L SS [4]. During recent surveillance activities, two SAVY 4000’s containing Solution Assay Instrument (SAI) solutions were opened. The SAI SAVY 4000’s contained plutonium (Pu) in 3M HCl solution in plastic volumetric flasks placed inside of

Studies on compatibility of energetic materials by thermal methods

Directory of Open Access Journals (Sweden)

Maria Alice Carvalho Mazzeu

2010-04-01

Full Text Available The chemical compatibility of explosives, pyrotechnics and propellants with those materials is studied to evaluate potential hazards when in contact with other materials during production, storage and handling. Compatibility can be studied by several thermal methods as DSC (differential scanning calorimetry, TG (Thermogravimetry, VST (Vacuum stability test and others. The test methods and well defined criteria are the most important elements when a compatibility study is being accomplished. In this paper, the compatibility of two very important high explosives used in ammunition, RDX (Cyclo-1,3,5-trimethylene-2,4,6-trinitramine and HMX (Cyclotetramethylene tetranitramine was studied with the materials: fluoroelastomer (Viton and powdered aluminum (Al, using DSC and VST methods. The criteria to judge the compatibility between materials is based on a standardization agreement (STANAG 4147, 2001, and the final conclusion is that explosives and this materials are compatible, but in DSC it was observed that the peak of decomposition temperature of the admixture of RDX with Al decreased in 3º C and another peak appeared after the decomposition peak.

Radiation durability of polymeric materials in solid polymer electrolyzer for fusion tritium plant

International Nuclear Information System (INIS)

Iwai, Yasunori; Yamanishi, Toshihiko; Hiroki, Akihiro; Tamada, Masao

2009-02-01

This document presents the radiation durability of various polymeric materials applicable to a solid-polymer-electrolyte (SPE) water electrolyzer to be used in the tritium facility of fusion reactor. The SPE water electrolyzers are applied to the water detritiation system (WDS) of the ITER. In the ITER, an electrolyzer should keep its performance during two years operation in the tritiated water of 9TBq/kg, the design tritium concentration of the ITER. The tritium exposure of 9TBq/kg for two years is corresponding to the irradiation of no less than 530 kGy. In this study, the polymeric materials were irradiated with γ-rays or with electron beams at various conditions up to 1600 kGy at room temperature or at 343 K. The change in mechanical and functional properties were investigated by stress-strain measurement, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray photoelectron spectra (XPS), and so on. Our selection of polymeric materials for a SPE water electrolyzer used in a radiation environment was Pt + Ir applied Nafion N117 ion exchange membrane, VITON O-ring seal and polyimide insulator. (author)

Investigations on materials for small Stirling refrigerators in long-term operation

International Nuclear Information System (INIS)

Engelland, W.; Kose, V.

1990-04-01

Work is being carried out world-wide on the development of refrigerators with low power requirements for the cooling of high-temperature superconductors and other cryoelectronic components. Due to its good efficiency factor, the well-known Stirling principle is particularly suitable for this purpose, but the increasing contamination of the working gases needed for the process which is caused by outgassing and the permeability to gas of the epoxide resins and other materials generally used makes it prone to interference over long periods of operation. For the first time, DURAN glass has been taken as a regenerator material and tested with successful results over a long period of operation in a small Stirling refrigerator designed and constructed for this purpose. A commercial double-membrane compressor which was also to be tested in long-term operation was converted into a dynamic pressure source and used as a refrigerator component. With this refrigerator, it was possible to maintain a temperature of 34 K over a continous period of operation of 77 days. Parallel to this, mass spectrometric permeation measurements were carried out on a compressor membrane made of VITON in which the water vapour of the atmosphere dominated. (orig.) [de

Basis of property limits for inflatable seal fluoroelastomers

International Nuclear Information System (INIS)

Sinha, N.K.; Raj, Baldev

2012-01-01

Identification of a set of governing physico-mechanical properties for inflatable seals of Prototype Fast Breeder Reactor (PFBR) and specification of their limits is described based on operating requirements, design practices and results from seal development. The limits of tensile strength, elongation at break, hardness, tear strength, fluid compatibility, compression set and specific gravity defined for the Viton GBL 200S/600S based inflatable seal formulation provide a standardized framework for regular production of reactor seals and a streamlined approach for compounding, design, manufacture and quality control. This assures significant reduction of efforts during the envisaged unification of Fast Breeder Reactor sealing based on four variations of inflatable seal compound which could result in a universal design code apart from significant gains in safety, reliability and life. The property set has potential use in Pressurized Heavy Water Reactor and Advanced Heavy Water Reactor. Inclusion of factors such as batch-to-batch variations of compound properties and their reproducibility during laboratory measurements, hot tensile behavior of fluoroelastomer, long term ageing effects and the margin of safety at the end of seal design life ensures the utility of property set in attaining its intended objective.

Water Ingress Testing of the Turbula Jar and U-233 Lead Pig Containers

Energy Technology Data Exchange (ETDEWEB)

Reeves, Kirk Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Karns, Tristan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Paul Herrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-11-02

Understanding the water ingress behavior of containers used at the TA-55 Plutonium Facility has significant implications for criticality safety. The purpose of this report is to document the water ingress behavior of the Turbula Jar with Bakelite lid and Viton gaskets (Turbula Jar) used in oxide blending operations and the U-233 lead pig container used to store and transport U-233 material. The technical basis for water resistant containers at TA-55 is described in LA-UR-15-22781, “Water Resistant Container Technical Basis Document for the TA-55 Criticality Safety Program.” Testing of the water ingress behavior of various containers is described in LA-CP-13-00695, “Water Penetration Tests on the Filters of Hagan and SAVY Containers,” LA-UR-15-23121, “Water Ingress into Crimped Convenience Containers under Flooding Conditions,” and in LA-UR- 16-2411, “Water Ingress Testing for TA-55 Containers.” Water ingress criteria are defined in TA55-AP-522 “TA-55 Criticality Safety Program”, and in PA-RD-01009 “TA55 Criticality Safety Requirements.” The water ingress criteria for submersion is no more than 50 ml of water ingress at a 6” water column height for a period of 2 hours.

Molten salt destruction as an alternative to open burning of energetic material wastes

International Nuclear Information System (INIS)

Upadhye, R.S.; Watkins, B.E.; Pruneda, C.O.; Brummond, W.A.

1994-01-01

LLNL has built a small-scale (about 1 kg/hr throughput unit to test the destruction of energetic materials using the Molten Salt Destruction (MSD) process. We have modified the unit described in the earlier references to inject energetic waste material continuously into the unit. In addition to the HMX, other explosives we have destroyed include RDX, PETN, ammonium picrate, TNT, nitroguanadine, and TATB. We have also destroyed a liquid gun propellant comprising hydroxyl ammonium nitrate, triethanolammonium nitrate and water. In addition to these pure components, we have destroyed a number of commonly used formulations, such as LX-10 (HMX/Viton), LX-16 (PETN/FPC461, LX-17 (TATB/Kel F), and PBX-9404 (HMX)/CEF/Nitro cellulose). Our experiments have demonstrated that energetic materials can be safely and effectively treated by MSD.We have also investigated the issue of steam explosions in molten salt units, both experimentally and theoretically, and concluded that steam explosions can be avoided under proper design and operating conditions. We are currently building a larger unit (nominal capacity 5 kg/hr,) to investigate the relationship between residence time, temperature, feed concentration and throughputs, avoidance of back-burn, a;nd determination of the products of combustion under different operating conditions

Presence of mercury in natural gas

International Nuclear Information System (INIS)

Gijselman, P.B.

1991-01-01

This paper describes the occupational health programme used to ensure that NAM and contractor personnel of the Nederlandse Aardolie Mij (NAM) exposed to mercury, common in Dutch gas, are adequately protected through the correct use of Personal Protective Equipment (PPE), proper instruction and suitable work procedures. To avoid health damage due to mercury exposure during maintenance and shutdown activities the occupational health department of NAM set up a programme covering 3 activities: monitoring of atmospheric air; sampling of inspired air during work, and measurement of mercury excretion in urine of workers instruction of company and contractor personnel consultancy during preparation of work instructions. The monitoring program showed that, through correct use of PPE, staff do not exhibit mercury concentration levels exceeding the human toxicity limit (100 ug/g creatinine) even after exposure to mercury vapor concentrations above the TLV of 0.5 mg/m 3 . The correct use of PPE is a result of the instruction programme which also promotes increased awareness for personnel of the harmful effects of mercury. Finally, the provision of consultancy during the preparation of work instructions has contributed to various measures; for instance, staff wearing plastic (Viton) protective suits may not work longer than 2 hours continuously to avoid heat exhaustion

A rotation-symmetric, position-sensitive annular detector for maximum counting rates

International Nuclear Information System (INIS)

Igel, S.

1993-12-01

The Germanium Wall is a semiconductor detector system containing up to four annular position sensitive ΔE-detectors from high purity germanium (HPGe) planned to complement the BIG KARL spectrometer in COSY experiments. The first diode of the system, the Quirl-detector, has a two dimensional position sensitive structure defined by 200 Archimedes' spirals on each side with opposite orientation. In this way about 40000 pixels are defined. Since each spiral element detects almost the same number of events in an experiment the whole system can be optimized for maximal counting rates. This paper describes a test setup for a first prototype of the Quirl-detector and the results of test measurements with an α-source. The detector current and the electrical separation of the spiral elements were measured. The splitting of signals due to the spread of charge carriers produced by an incident ionizing particle on several adjacent elements was investigated in detail and found to be twice as high as expected from calculations. Its influence on energy and position resolution is discussed. Electronic crosstalk via signal wires and the influence of noise from the magnetic spectrometer has been tested under experimental conditions. Additionally, vacuum feedthroughs based on printed Kapton foils pressed between Viton seals were fabricated and tested successfully concerning their vacuum and thermal properties. (orig.)

Effect of alternative aging and accident simulations on polymer properties

International Nuclear Information System (INIS)

Bustard, L.D.; Chenion, J.; Carlin, F.; Alba, C.; Gaussens, G.; LeMeur, M.

1985-05-01

The influence of accident irradiation, steam, and chemical spray exposures on the behavior of twenty-three age-preconditioned polymer sample sets (twenty-one different materials) has been investigated. The test program varied the following conditions: (1) Accident simulations of irradiation and thermodynamic (steam and chemical spray) conditions were performed both sequentially and simultaneously. (2) Accident thermodynamic (steam and chemical spray) exposures were performed both with and without air present during the exposures. (3) Sequential accident irradiations were performed both at 28 0 C and 70 0 C. (4) Age preconditioning was performed both sequentially and simultaneously. (5) Sequential aging irradiations were performed both at 27 0 C and 70 0 C. (6) Sequential aging exposures were performed using two sequences: (1) thermal followed by irradiation and (2) irradiation followed by thermal. We report both general trends applicable to a majority of the tested materials as well as specific results for each polymer. Our data base consists of ultimate tensile properties at the completion of the accident exposure for three XLPO and XLPE, five EPR and EPDM, two CSPE (HYPALON), one CPE, one VAMAC, one polydiallylphtalate, and one PPS material. We also report bend test results at completion of the accident exposures for two TEFZEL materials and permanent set after compression results for three EPR, one VAMAC, one BUNA N, one SILICONE, and one VITON material

Microchambers with Solid-State Phosphorescent Sensor for Measuring Single Mitochondrial Respiration.

Science.gov (United States)

Pham, Ted D; Wallace, Douglas C; Burke, Peter J

2016-07-09

It is now well established that, even within a single cell, multiple copies of the mitochondrial genome may be present (genetic heteroplasmy). It would be interesting to develop techniques to determine if and to what extent this genetic variation results in functional variation from one mitochondrion to the next (functional heteroplasmy). Measuring mitochondrial respiration can reveal the organelles' functional capacity for Adenosine triphosphate (ATP) production and determine mitochondrial damage that may arise from genetic or age related defects. However, available technologies require significant quantities of mitochondria. Here, we develop a technology to assay the respiration of a single mitochondrion. Our "micro-respirometer" consists of micron sized chambers etched out of borofloat glass substrates and coated with an oxygen sensitive phosphorescent dye Pt(II) meso-tetra(pentafluorophenyl)porphine (PtTFPP) mixed with polystyrene. The chambers are sealed with a polydimethylsiloxane layer coated with oxygen impermeable Viton rubber to prevent diffusion of oxygen from the environment. As the mitochondria consume oxygen in the chamber, the phosphorescence signal increases, allowing direct determination of the respiration rate. Experiments with coupled vs. uncoupled mitochondria showed a substantial difference in respiration, confirming the validity of the microchambers as single mitochondrial respirometers. This demonstration could enable future high-throughput assays of mitochondrial respiration and benefit the study of mitochondrial functional heterogeneity, and its role in health and disease.

Phase Behavior of Three PBX Elastomers in High-Pressure Chlorodifluoromethane

Science.gov (United States)

Lee, Byung-Chul

2017-10-01

The phase equilibrium behavior data are presented for three kinds of commercial polymer-bonded explosive (PBX) elastomers in chlorodifluoromethane (HCFC22). Levapren^{{registered }} ethylene- co-vinyl acetate (LP-EVA), HyTemp^{{registered }} alkyl acrylate copolymer (HT-ACM), and Viton^{{registered }} fluoroelastomer (VT-FE) were used as the PBX elastomers. For each elastomer + HCFC22 system, the cloud point (CP) and/or bubble point (BP) pressures were measured while varying the temperature and elastomer composition using a phase equilibrium apparatus fitted with a variable-volume view cell. The elastomers examined in this study indicated a lower critical solution temperature phase behavior in the HCFC22 solvent. LP-EVA showed the CPs at temperatures of 323 K to 343 K and at pressures of 3 MPa to 10 MPa, whereas HT-ACM showed the CPs at conditions between 338 K and 363 K and between 4 MPa and 12 MPa. For the LP-EVA and HT-ACM elastomers, the BP behavior was observed at temperatures below about 323 K. For the VT-FE + HCFC22 system, only the CP behavior was observed at temperatures between 323 K and 353 K and at pressures between 6 MPa and 21 MPa. As the elastomer composition increased, the CP pressure increased, reached a maximum value at a specific elastomer composition, and then remained almost constant.

TN trademark FLEX: a new generation of fluorocarbon o-rings developed by COGEMA logistics with enhanced characteristics at low temperature (-40 C)

International Nuclear Information System (INIS)

Issard, H.; Andre, R.

2004-01-01

Three main types of elastomers are used for the sealing of radioactive material transport casks with elastomeric gaskets: EPDM, fluorocarbons type Viton registered (standard designation: FKM) and silicon rubbers. Each rubber has specific characteristics in terms of temperature range, permeability, coefficient of expansion.. For the casks where high temperatures can be reached (200 C in continuous using), FKM gaskets are generally used. The problem is that this type of gasket does not guarantee the leaktightness at -40 C, which is a regulatory requirement. Two solutions are generally used: to specify a minimum heat load or a minimum ambient temperature. The direct consequence is that it is impossible to get B(U) approvals on the new concepts when FKM gaskets are used but only B(M) approvals, which generate significant additional justification costs (multiple submittals of Safety Analysis Reports, calculation of the minimum heat load or of the minimum ambient temperature..). Thus, it is important to develop gaskets with the same performance as FKM gaskets at high temperature but with enhanced performance at low temperature (and mainly, which guarantee the leaktightness at -40 C). COGEMA LOGISTICS has qualified a new generation of fluorocarbon O-rings (TN trademark FLEX gaskets) which can be used in continuous service on a -47 C/+200 C temperature range. TN trademark FLEX gaskets will be implemented on new casks designs

Development of inflatable seals for the rotatable plugs of sodium cooled fast breeder reactors. Pt. II. R and D necessities and development across the world. A review

International Nuclear Information System (INIS)

Sinha, Nilay K.; Raj, Baldev

2013-01-01

Identification of development areas and their implementation for rotatable plug (RP) inflatable seals of Na cooled, 500 Mw (e) Prototype Fast Breeder Reactor (PFBR) and 40 MW (t) Fast Breeder Test Reactor (FBTR) are described, largely based on a late 1990s survey of cover gas seal development (1950s - early 1990s) which defined a set of shortlisted design options and developmental strategy to minimize effort, cost and time. Comparative study of top shield sealing and evolving FBR designs suggest suitability of inflatable seal as primary barrier in RPs. International experience identified choice and qualification of seal elastomer under synergistic degrading environment of reactor as the prime element of development. The low pressure, non-reinforced, unbeaded, PFBR inflatable seal (made of 50/50 blend of Viton registered GBL 200S/600S) developed for 10 y life provides a unification scheme for nuclear elastomeric sealing based on 5 peroxide cured fluoroelastomer blend formulations, 1 finite element analysis approach, 1 Teflon-like plasma coating technique and 2 manufacturing processes promising significant gains in standardization, economy and safety. Uniqueness was ab initio development in the absence of established industry or readymade supply. R and D necessities for inflatable seals and their development across the world are given closer look in Part II of the review in continuation of Part I. (orig.)

Chemical compatibility screening results of plastic packaging to mixed waste simulants

International Nuclear Information System (INIS)

Nigrey, P.J.; Dickens, T.G.

1995-01-01

We have developed a chemical compatibility program for evaluating transportation packaging components for transporting mixed waste forms. We have performed the first phase of this experimental program to determine the effects of simulant mixed wastes on packaging materials. This effort involved the screening of 10 plastic materials in four liquid mixed waste simulants. The testing protocol involved exposing the respective materials to ∼3 kGy of gamma radiation followed by 14 day exposures to the waste simulants of 60 C. The seal materials or rubbers were tested using VTR (vapor transport rate) measurements while the liner materials were tested using specific gravity as a metric. For these tests, a screening criteria of ∼1 g/m 2 /hr for VTR and a specific gravity change of 10% was used. It was concluded that while all seal materials passed exposure to the aqueous simulant mixed waste, EPDM and SBR had the lowest VTRs. In the chlorinated hydrocarbon simulant mixed waste, only VITON passed the screening tests. In both the simulant scintillation fluid mixed waste and the ketone mixture simulant mixed waste, none of the seal materials met the screening criteria. It is anticipated that those materials with the lowest VTRs will be evaluated in the comprehensive phase of the program. For specific gravity testing of liner materials the data showed that while all materials with the exception of polypropylene passed the screening criteria, Kel-F, HDPE, and XLPE were found to offer the greatest resistance to the combination of radiation and chemicals

Mechanical design of beam extractor system for cyclotron proton 13 MeV

International Nuclear Information System (INIS)

Ihwanul Aziz; Widdi Usada

2012-01-01

Mechanical design of beam extractor system for 13 MeV proton cyclotron has been carried out. In cyclotron there are two extractor systems, the first is electrostatic deflector system, and the second is stripper system. This stripper serves to change negative charged of hydrogen ions to become positive charged hydrogen ions (protons). In proton cyclotron, the carbon foil is used as a stripper. Mechanical extractor system consists of a carbon foil holder and a driver system to control the position of foil holder and to change the foil. The driver system consists of a stepper motor extractor, a feed-through, a gear, a shaft, and a buffer. After some calculation the obtained component data as the foil follow holder is made of aluminum has total length of 12.25 mm, total width of 10 mm and the total thickness of 2.5 mm, while the length of each extractor arm is made of aluminum 90 mm, width is 30 mm, its height is 10 mm , the total volume is 7,392 x 10-5 and a mass of 0.1995 kg. Extractor drive system includes a stepper motor having a maximum of 4 lb-ft of torque, feed through, gear, shaft, and a buffer. Required torque is 0.16 Nm or 0.12 lb-ft diameter shaft to support the extractor arm is 29 mm. Bolt fastener for the buffer is a type of metric M6 bolt, so that the used seals viton O-ring with seal diameter of 6 mm and DN 40 CF flange. (author)

Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

International Nuclear Information System (INIS)

Prasad, D N; Ayyappan, R; Kamble, L P; Singh, J P; Muralikrishna, L V; Alex, M; Balagi, V; Mukhopadhyay, P K

2008-01-01

Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm 2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ∼1 x 10 -5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mmx160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face and diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6x10 -9 m bar ltr/sec in vacuum mode and 2x10 -7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5x10 -5 mbar, the new valve achieved vacuum 7.4x10 -6 mbar in the same time under the same conditions

Permeation of Telone EC through protective gloves.

Science.gov (United States)

Zainal, Hanaa; Que Hee, Shane S

2005-09-30

Telone is a potent fumigant that is based on the chlorinated unsaturated hydrocarbon, 1,3-dichloropropene (1,3-DCP). It is often applied without dilution and so poses severe inhalation and air pollution threats. Urinary metabolites of 1,3-DCP have been detected after Telone skin exposure, so that preventing dermal exposure is also important. The objective of the study was to assess if nitrile and multi-layer ("laminated") gloves provide adequate protection against Telone EC formulation. To accomplish this, disposable (Safeskin) and chemically resistant (Sol-Vex) nitrile and laminated (Barrier mark and Silver Shield) glove materials were challenged by Telone EC with hexane liquid collection in an ASTM-type I-PTC-600 permeation cell. Analyses of cis- and trans-1,3-DCP in the collection fluid at specified times were performed on a moderately polar capillary column by gas chromatography-electron capture detection. Telone EC caused microholes in both nitrile materials, though the chemically protective material was degraded slower than the disposable nitrile. The laminated gloves offered limited protection. Silver Shield protected best because 1.5-2.3 mg 1,3-DCP permeated by 8 h relative to 2.5-7.6 mg for Barrier, implying about 2.5 times more protection for 8 h. Even for Silver Shield, the extent of protection was inadequate as illustrated by a risk assessment of the skin exposure situation. The normalized breakthrough times for both types of laminated gloves varied between 27 and 60 min. It is recommended that Viton gloves still be worn for protection.

Shock Initiation of Damaged Explosives

Energy Technology Data Exchange (ETDEWEB)

Chidester, S K; Vandersall, K S; Tarver, C M

2009-10-22

Explosive and propellant charges are subjected to various mechanical and thermal insults that can increase their sensitivity over the course of their lifetimes. To quantify this effect, shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX, 15% Viton by weight) and PBX 9502 (95% TATB, 5% Kel-F by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. We report the behavior of the HMX-based explosive LX-04 that was damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermally damaged LX-04 charges were heated to 190 C for long enough for the beta to delta solid - solid phase transition to occur, and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while thermally damaged LX-04 was much more shock sensitive. Similarly, the insensitive explosive PBX 9502 was mechanically damaged using the same two techniques. Since PBX 9502 does not undergo a solid - solid phase transition but does undergo irreversible or 'rachet' growth when thermally cycled, thermal damage to PBX 9502 was induced by this procedure. As for LX-04, the thermally damaged PBX 9502 demonstrated a greater shock sensitivity than mechanically damaged PBX 9502. The Ignition and Growth reactive flow model calculated the increased sensitivities by igniting more damaged LX-04 and PBX 9502 near the shock front based on the measured densities (porosities) of the damaged charges.

A testing program to evaluate the effects of simulant mixed wastes on plastic transportation packaging components

International Nuclear Information System (INIS)

Nigrey, P.J.; Dickens, T.G.

1997-01-01

Based on regulatory requirements for Type A and B radioactive material packaging, a Testing Program was developed to evaluate the effects of mixed wastes on plastic materials which could be used as liners and seals in transportation containers. The plastics evaluated in this program were butadiene-acrylonitrile copolymer (Nitrile rubber), cross-linked polyethylene, epichlorohydrin, ethylene-propylene rubber (EPDM), fluorocarbons, high-density polyethylene (HDPE), butyl rubber, polypropylene, polytetrafluoroethylene, and styrene-butadiene rubber (SBR). These plastics were first screened in four simulant mixed wastes. The liner materials were screened using specific gravity measurements and seal materials by vapor transport rate (VTR) measurements. For the screening of liner materials, Kel-F, HDPE, and XLPE were found to offer the greatest resistance to the combination of radiation and chemicals. The tests also indicated that while all seal materials passed exposure to the aqueous simulant mixed waste, EPDM and SBR had the lowest VTRs. In the chlorinated hydrocarbon simulant mixed waste, only Viton passed the screening tests. In both the simulant scintillation fluid mixed waste and the ketone mixture waste, none of the seal materials met the screening criteria. Those materials which passed the screening tests were subjected to further comprehensive testing in each of the simulant wastes. The materials were exposed to four different radiation doses followed by exposure to a simulant mixed waste at three temperatures and four different exposure times (7, 14, 28, 180 days). Materials were tested by measuring specific gravity, dimensional, hardness, stress cracking, VTR, compression set, and tensile properties. The second phase of this Testing Program involving the comprehensive testing of plastic liner has been completed and for seal materials is currently in progress

Effects of simulant mixed waste on EPDM and butyl rubber

International Nuclear Information System (INIS)

Nigrey, P.J.; Dickens, T.G.

1997-11-01

The authors have developed a Chemical Compatibility Testing Program for the evaluation of plastic packaging components which may be used in transporting mixed waste forms. In this program, they have screened 10 plastic materials in four liquid mixed waste simulants. These plastics were butadiene-acrylonitrile copolymer (Nitrile) rubber, cross-linked polyethylene, epichlorohydrin rubber, ethylene-propylene (EPDM) rubber, fluorocarbons (Viton and Kel-F trademark), polytetrafluoro-ethylene (Teflon), high-density polyethylene, isobutylene-isoprene copolymer (Butyl) rubber, polypropylene, and styrene-butadiene (SBR) rubber. The selected simulant mixed wastes were (1) an aqueous alkaline mixture of sodium nitrate and sodium nitrite; (2) a chlorinated hydrocarbon mixture; (3) a simulant liquid scintillation fluid; and (4) a mixture of ketones. The screening testing protocol involved exposing the respective materials to approximately 3 kGy of gamma radiation followed by 14-day exposures to the waste simulants at 60 C. The rubber materials or elastomers were tested using Vapor Transport Rate measurements while the liner materials were tested using specific gravity as a metric. The authors have developed a chemical compatibility program for the evaluation of plastic packaging components which may be incorporated in packaging for transporting mixed waste forms. From the data analyses performed to date, they have identified the thermoplastic, polychlorotrifluoroethylene, as having the greatest chemical compatibility after having been exposed to gamma radiation followed by exposure to the Hanford Tank simulant mixed waste. The most striking observation from this study was the poor performance of polytetrafluoroethylene under these conditions. In the evaluation of the two elastomeric materials they have concluded that while both materials exhibit remarkable resistance to these environmental conditions, EPDM has a greater resistance to this corrosive simulant mixed waste

CO2/ brine substitution experiments at simulated reservoir conditions

Science.gov (United States)

Kummerow, Juliane; Spangenberg, Erik

2015-04-01

Capillary properties of rocks affect the mobility of fluids in a reservoir. Therefore, the understanding of the capillary pressure behaviour is essential to assess the long-term behaviour of CO2 reservoirs. Beyond this, a calibration of the petrophysical properties on water saturation of reservoir rocks at simulated in situ conditions is crucial for a proper interpretation of field monitoring data. We present a set-up, which allows for the combined measurements of capillary pressure, electric resistivity, and elastic wave velocities under controlled reservoir conditions (pconf = 400 bar, ppore = 180 bar, T = 65 ° C) at different brine-CO2 saturations. The capillary properties of the samples are measured using the micropore membrane technique. The sample is jacketed with a Viton tube (thickness = 4 mm) and placed between two current electrode endcaps, which as well contain pore fluid ports and ultrasonic P and S wave transducers. Between the sample and the lower endcap the hydrophilic semi-permeable micro-pore membrane (pore size = 100 nm) is integrated. It is embedded into filter papers to establish a good capillary contact and to protect the highly sensitive membrane against mechanical damage under load. Two high-precision syringe pumps are used to displace a quantified volume of brine by CO2 and determine the corresponding sample saturation. The fluid displacement induces a pressure gradient along the sample, which corresponds to the capillary pressure at a particular sample saturation. It is measured with a differential pressure sensor in the range between 0 - 0.2 MPa. Drainage and imbibition cycles are performed to provide information on the efficiency of capillary trapping and to get a calibration of the petrophysical parameters of the sample.

Natural and anthropogenic phenomena affecting the historical landslide trend in the Subappennino Dauno (southern Italy)

Science.gov (United States)

Lonigro, Teresa; Santaloia, Francesca; Polemio, Maurizio

2014-05-01

Protection, and also documents belonging to a research project (PS_119; Cotecchia et al. 2010). According to the landslide data collected, the landslide events resulted to be 175 in the study area. The trend analyses show that the landslide occurrence was increased with the time, despite of the rainfall and temperature data are not prone to landsliding. As a matter of fact, the trend of both the monthly rainfall and the rainfall intensity decreases, and the temperature and the wet days show a positive trend during the period of reference. The trend of the short-duration rainfall results generally to decrease. Not existing an evident relationship between climate variability and the increase of landslide occurrence, some other factors should be considered, as, for instance, the poor mechanical soil properties, the role of anthropogenic modifications and the mismanagement of risk-prone areas. In this regards, the preliminary results obtained from the data analyses of the land use and the populations could partly justify the increasing trend of landslide occurrence. More details on previous results of this research activity were recently published (Cotecchia et al., 2010; Polemio and Lonigro, 2011 and 2013; Santaloia et al., 2012). References Cotecchia F., Santaloia F., Lollino P., C. Vitone, G. Mitaritonna (2010) "Deterministic landslide hazard assessment at regional scale". Geoflorida 2010, : 3130-3139. Santaloia F, Cotecchia F, Vitone C (2012) "Applicazione dei metodi avanzati al fronte appenninico apulo-lucano: analisi di I livello. In: Cascini L. (Ed) "Criteri di zonazione della suscettibilità e della pericolosità da frane innescate da eventi estremi (piogge e sisma)"; 130-140, Padova:Composervice srl. Polemio M., Lonigro T. (2011) "Variabilità climatica e ricorrenza delle calamità idrogeologiche in Puglia". In: "Le modificazioni climatiche e i rischi naturali", Polemio M. (Ed.), CNR IRPI, Bari, pp. 13-16. Polemio M., Lonigro T. (2013) "Climate variability and landslide

Whole glove permeation of cyclohexanol through disposable nitrile gloves on a dextrous robot hand and comparison with the modified closed-loop ASTM F739 method 1. No fist clenching.

Science.gov (United States)

Mathews, Airek R; Que Hee, Shane S

2017-04-01

The aim was to develop a whole glove permeation method for cyclohexanol to generate permeation parameter data for a non-moving dextrous robot hand (normalized breakthrough time t b , standardized breakthrough time t s , steady state permeation rate P s , and diffusion coefficient D). Four types of disposable powderless, unsupported, and unlined nitrile gloves from the same producer were investigated: Safeskin Blue and Kimtech Science Blue, Purple, and Sterling. The whole glove method developed involved a peristaltic pump for water circulation through chemically resistant Viton tubing to continually wash the inner surface of the test glove via holes in the tubing, a dextrous robot hand operated by a microprocessor, a chemically protective nitrile glove to protect the robot hand, an incubator to maintain 35°C temperature, and a hot plate to maintain 35°C at the sampling point of the circulating water. Aliquots of 1.0 mL were sampled at regular time intervals for the first 60 min followed by removal of 0.5 mL aliquots every hour to 8 hr. Quantification was by the internal standard method after gas chromatography-selective ion electron impact mass spectrometry using a non-polar capillary column. The individual glove values of t b and t s differed for the ASTM closed loop method except for Safeskin Blue, but did not for the whole glove method. Most of the kinetic parameters agreed within an order of magnitude for the two techniques. The order of most protective to least protective glove was Blue and Safeskin, then Purple followed by Sterling for the whole gloves. The analogous order for the modified F739 ASTM closed loop method was: Safeskin, Blue, Purple, and Sterling, almost the same as for the whole glove. The Sterling glove was "not recommended" from the modified ASTM data, and was "poor" from the whole glove data.

Effects of simulant mixed waste on EPDM and butyl rubber

International Nuclear Information System (INIS)

Nigrey, P.J.; Dickens, T.G.

1998-01-01

We have developed a Chemical Compatibility Testing Program for the evaluation of plastic packaging components which may be used in transporting mixed waste forms. In this program, we have screened 10 plastic materials in four liquid mixed waste simulants. These plastics were butadiene-acrylonitrile copolymer (Nitrile) rubber, cross-linked polyethylene, epi-chloro-hydrin rubber, ethylene-propylene (EPDM) rubber, fluorocarbons (Viton and Kel-F), poly-tetrafluoroethylene (Teflon), high-density polyethylene, isobutylene-isoprene copolymer (Butyl) rubber, polypropylene, and styrene-butadiene (SBR) rubber. The selected simulant mixed wastes were (1) an aqueous alkaline mixture of sodium nitrate and sodium nitrite; (2) a chlorinated hydrocarbon mixture; (3) a simulant liquid scintillation fluid; and (4) a mixture of ketones. The screening testing protocol involved exposing the respective materials to ∼3 kGy of gamma radiation followed by 14-day exposures to the waste simulants at 60 deg. C. The rubber materials or elastomers were tested using VTR measurements while the liner materials were tested using specific gravity as a metric. For these tests, screening criteria of ∼1 g/hr/m 2 for VTR and specific gravity change of 10% were used. Those materials that failed to meet these criteria were judged to have failed the screening tests and were excluded from the next phase of this experimental program. We have completed the comprehensive testing phase of liner materials in a simulant Hanford Tank waste consisting of an aqueous alkaline mixture of sodium nitrate and sodium nitrite. From the data analyses performed, we have identified the chloro-fluorocarbon Kel-F as having the greatest chemical durability after having been exposed to gamma radiation followed by exposure to the aqueous alkaline simulant mixed waste. The most striking observation from this study was the extremely poor performance of Teflon under these conditions. We have also completed the comprehensive

Characterization of ion processes in a GC/DMS air quality monitor by integration of the instrument to a mass spectrometer.

Science.gov (United States)

Limero, T F; Nazarov, E G; Menlyadiev, M; Eiceman, G A

2015-02-07

The air quality monitor (AQM), which included a portable gas chromatograph (GC) and a detector was interfaced to a mass spectrometer (MS) by introducing flow from the GC detector to the atmospheric pressure ion source of the MS. This small GC system, with a gas recirculation loop for carrier and detector make-up gases, comprised an inlet to preconcentrate volatile organic compounds (VOCs) in air, a thermal desorber before the GC column, a differential mobility spectrometer (DMS), and another DMS as an atmospheric pressure ionization source for the MS. Return flow to the internally recirculated air system of the AQM's DMS was replenished using purified air. Although ions and unreacted neutral vapors flowed from the detector through Viton® tubing into the source of the MS, ions were not detected in the MS without the auxillary ion source, (63)Ni as in the mobility detector. The GC-DMS-MS instrument provided a 3-D measurement platform (GC, DMS, and MS analysis) to explore the gas composition inside the GC-DMS recirculation loop and provide DMS-MS measurement of the components of a complex VOC mixture with performance significantly enhanced by mass-analysis, either with mass spectral scans or with an extracted ion chromatogram. This combination of a mobility spectrometer and a mass spectrometer was possible as vapors and ions are carried together through the DMS analyzer, thereby preserving the chromatographic separation efficiency. The critical benefit of this instrument concept is that all flows in and through the thoroughly integrated GC-DMS analyzer are kept intact allowing a full measure of the ion and vapor composition in the complete system. Performance has been evaluated using a synthetic air sample and a sample of airborne vapors in a laboratory. Capabilities and performance values are described using results from AQM-MS analysis of purified air, ambient air from a research laboratory in a chemistry building, and a sample of synthetic air of known composition

Projeto do sistema anti-ressonante da fiação dos transdutores para o detector Mario Schenberg

Science.gov (United States)

Vieira, S. J.., Jr.; Melo, J. L.

2003-08-01

O detector de ondas gravitacionais Mario Schenberg está sendo projetado e construído pelo grupo Gráviton. Sua construção está ocorrendo no Laboratório de Estado Sólido e Baixas Temperaturas (LESBT) da Universidade de São Paulo, na cidade de São Paulo. Esse detector possui uma massa ressonante esférica de cobre-alumínio, com 65 cm de diâmetro, pesando aproximadamente 1150 Kg, suspensa por um sistema de isolamento vibracional, que se encontra em fase de testes preliminares. A real eficácia desse sistema, entretanto, só poderá ser comprovada quando o detector estiver aparelhado com, pelo menos, um transdutor eletromecânico de altíssima sensibilidade acoplado à massa ressonante. Neste momento, não só este sistema de isolamento vibracional será posto em teste, como o do projeto da fiação que transporta os sinais de microondas até os transdutores e destes para a pré-amplificação. Apesar dessa fiação ter sido projetada para não apresentar nenhum contato com a superfície esférica da antena, de maneira a não haver nenhuma transmissão de ruído vibracional do laboratório para esta, deve-se minimizar o ruído microfônico produzido nessa fiação por oscilações mecânicas, uma vez que ela não utiliza nenhum sistema de isolamento vibracional. Com o intuito de resolver este problema, projetamos uma estrutura, formada por pequenos cilindros conectados por barras, a qual não terá nenhuma ressonância mecânica na faixa de freqüências de interesse para detecção (3000 - 3400 Hz). Desta forma, as vibrações nessa faixa não serão amplificadas. O projeto foi feito usando iterativamente, de maneira a otimizar os resultados obtidos, o programa de elementos finitos Msc/Nastran. Através de simulações feitas neste programa, determinamos os parâmetros geométricos ideais a serem utilizados, os quais proporcionam a maior região espectral de interesse livre de ressonâncias.

Fifth Interim Status Report: Model 9975 PCV O-Ring Fixture Long-Term Leak Performance

International Nuclear Information System (INIS)

Daugherty, W.; Hoffman, E.

2010-01-01

A series of experiments to monitor the aging performance of Viton reg. GLT O-rings used in the Model 9975 package has been ongoing for six years at the Savannah River National Laboratory. Sixty-seven mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 F. They were leak-tested initially and have been tested at nominal six month intervals to determine if they meet the criterion of leaktightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 F. High temperature aging continues for 36 GLT O-ring fixtures at 200--350 F. Room temperature leak test failures have been experienced in 5 of the GLT O-ring fixtures aging at 300 and 350 F, and in all 3 of the GLT O-ring fixtures aging at higher temperatures. No failures have yet been observed in GLT O-ring fixtures aging at 200 F for 30--48 months, which is still bounding to O-ring temperatures during storage in KAMS. High temperature aging continues for 6 GLT-S O-ring fixtures at 200--300 F. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 F. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 or 300 F for 19 months. For O-ring fixtures that have failed the room temperature leak test and been disassembled, the O-rings displayed a compression set ranging from 51--95%. This is significantly greater than seen to date for packages inspected during KAMS field surveillance (23% average). For GLT O-rings, service life based on the room temperature leak rate criterion is comparable to that predicted by compression stress relaxation (CSR) data at higher temperatures (350--400 F). While there are no comparable failure data yet at aging temperatures below 300 F, extrapolations of the data for GLT O-rings suggests that CSR model predictions provide a conservative prediction of service

Pre-ignition confinement and deflagration violence in LX-10 and PBX 9501

Energy Technology Data Exchange (ETDEWEB)

Tringe, J. W., E-mail: tringe2@llnl.gov; Glascoe, E. A.; McClelland, M. A.; Greenwood, D.; Chambers, R. D.; Springer, H. K.; Levie, H. W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2014-08-07

In thermal explosions of the nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)-based explosives LX-10 and PBX-9501, the pre-ignition spatial and temporal heating profile defines the ignition location. The ignition location then determines the extent of inertial confinement and the violence of the resulting deflagration. In this work, we present results of experiments in which ∼23 g cylinders of LX-10 and PBX 9501 in thin-walled aluminum confinement vessels were subjected to identical heating profiles but which presented starkly different energy release signatures. Post-explosion LX-10 containment vessels were completely fragmented, while the PBX 9501 vessels were merely ruptured. Flash x-ray radiography images show that the initiation location for the LX-10 is a few mm farther from the end caps of the vessel relative to the initiation location of PBX 9501. This difference increases deflagration confinement for LX-10 at the time of ignition and extends the pressurization time during which the deflagration front propagates in the explosive. The variation in the initiation location, in turn, is determined by the thermal boundary conditions, which differ for these two explosives because of the larger coefficient of thermal expansion and greater thermal stability of the Viton binder in LX-10 relative to the estane and bis(2,2-dinitropropyl) acetal/formal binder of the PBX 9501. The thermal profile and initiation location were modeled for LX-10 using the hydrodynamics and structures code ALE3D; results indicate temperatures in the vicinity of the ignition location in excess of 274 °C near the time of ignition. The conductive burn rates for these two explosives, as determined by flash x-ray radiography, are comparable in the range 0.1–0.2 mm/μs, somewhat faster than rates observed by strand burner experiments for explosives in the temperature range 150–180 °C and pressures up to 100 MPa. The thinnest-wall aluminum containment vessels

Pre-ignition confinement and deflagration violence in LX-10 and PBX 9501

International Nuclear Information System (INIS)

Tringe, J. W.; Glascoe, E. A.; McClelland, M. A.; Greenwood, D.; Chambers, R. D.; Springer, H. K.; Levie, H. W.

2014-01-01

In thermal explosions of the nitramine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX)-based explosives LX-10 and PBX-9501, the pre-ignition spatial and temporal heating profile defines the ignition location. The ignition location then determines the extent of inertial confinement and the violence of the resulting deflagration. In this work, we present results of experiments in which ∼23 g cylinders of LX-10 and PBX 9501 in thin-walled aluminum confinement vessels were subjected to identical heating profiles but which presented starkly different energy release signatures. Post-explosion LX-10 containment vessels were completely fragmented, while the PBX 9501 vessels were merely ruptured. Flash x-ray radiography images show that the initiation location for the LX-10 is a few mm farther from the end caps of the vessel relative to the initiation location of PBX 9501. This difference increases deflagration confinement for LX-10 at the time of ignition and extends the pressurization time during which the deflagration front propagates in the explosive. The variation in the initiation location, in turn, is determined by the thermal boundary conditions, which differ for these two explosives because of the larger coefficient of thermal expansion and greater thermal stability of the Viton binder in LX-10 relative to the estane and bis(2,2-dinitropropyl) acetal/formal binder of the PBX 9501. The thermal profile and initiation location were modeled for LX-10 using the hydrodynamics and structures code ALE3D; results indicate temperatures in the vicinity of the ignition location in excess of 274 °C near the time of ignition. The conductive burn rates for these two explosives, as determined by flash x-ray radiography, are comparable in the range 0.1–0.2 mm/μs, somewhat faster than rates observed by strand burner experiments for explosives in the temperature range 150–180 °C and pressures up to 100 MPa. The thinnest-wall aluminum containment vessels

FY2017 status report: Model 9975 O-ring fixture long-term leak performance

Energy Technology Data Exchange (ETDEWEB)

Daugherty, W. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-07-27

A series of experiments to monitor the aging performance of Viton® GLT and GLT-S O-rings used in the Model 9975 shipping package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperature. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups with GLT O-rings were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, a smaller test matrix with fourteen additional tests was initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. Leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The 300 °F GLT O-ring fixtures failed after 2.8 to 5.7 years at temperature. The remaining GLT O-ring fixtures aging at 300 ºF were retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 9 to 10.5 years, or in GLT O-ring fixtures aging at 270 ºF for 5.7 years. These aging temperatures bound O-ring temperatures anticipated during normal storage in K-Area Complex (KAC). Leak test failures have been experienced in all of the GLT-S O-ring fixtures aging at 300 ºF and above. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 and 250 ºF for 6.9 to 7.5 years. Data from the O-ring fixtures are generally consistent with results from compression stress relaxation testing, and provide confidence in the predictive models based on those results

The viability and performance characterization of nano scale energetic materials on a semiconductor bridge (SCB)

Science.gov (United States)

Strohm, Gianna Sophia

The move from conventional energetic composites to nano scale energetic mixtures (nano energetics) has shown dramatic improvement in energy release rate and sensitivity to ignition. A possible application of nano energetics is on a semiconductor bridge (SCB). An SCB typically requires a tenth of the energy input as compared to a bridge wire design with the same no-fire and is capable of igniting in tens of microseconds. For very low energy applications, SCBs can be manufactured to extremely small sizes and it is necessary to find materials with particle sizes that are even smaller to function. Reactive particles of comparable size to the bridge can lead to problems with ignition reliability for small bridges. Nano-energetic composites and the use of SCBs have been significantly studied individually, however, the process of combining nano energetics with an SCB has not been investigated extensively and is the focus of this work. Goals of this study are to determine if nano energetics can be used with SCBs to further reduce the minimum energy required and improve reliability. The performance of nano-scale aluminum (nAl) and bismuth oxide (Bi2O3) with nitrocellulose (NC), Fluorel(TM) FC 2175 (chemically equivalent to VitonRTM) and Glycidyl Azide Polymer (GAP) as binders where quantified initially using the SenTest(TM) algorithm at three weight fractions (5, 7, and 9%) of binder. The threshold energy was calculated and compared to previous data using conventional materials such as zirconium potassium chlorate (ZPC), mercuric 5-Nitrotetrazol (DXN-1) and titanium sub-hydride potassium per-chlorate (TSPP). It was found that even though there where only slight differences in performance between the binders with nAl/Bi2O 3 at any of the three binder weight fractions, the results show that these nano energetic materials require about half of the threshold energy compared to conventional materials using an SCB with an 84x42 mum bridge. Binder limit testing was conducted to

Choice of rotatable plug seals for prototype fast breeder reactor: Review of historical perspectives

Energy Technology Data Exchange (ETDEWEB)

Sinha, N.K., E-mail: nksinha@igcar.gov.in; Raj, Baldev, E-mail: baldev.dr@gmail.com

2015-09-15

above-TS height and diameters substantially (vis-à-vis mid-1980s 4-loop, PFBR RP design with freeze-inflatable combination) which assures a significant step towards enhanced safety, economy and life (60 y at 85% capacity factor) of future FBRs, supported by stability maximisation, stress-minimisation and ease of critical component alignment. Closeness of inflatable seal operating requirements (25 kPa—120 °C—23 mGy/h) to TS barrier representative conditions (70 kPa—110 °C—23 mGy/h) are combined with key findings from R&D on elastomer, seal and coating of Indian FBRs to illustrate that critical elastomeric sealing of MOX fuelled FBRs, Pressurised Heavy Water Reactors and Advanced Heavy Water Reactor could be unified taking 50:50 blend formulation of Viton GBL 200S and 600S (developed for inflatable seal) as cornerstone and finite element based design as facilitator. It is further indicated that minimisation of synergistic ageing load on the fluoroelastomer inflatable-backup sealing combination by sodium dip seal could ensure 1 replacement during reactor life.

Los Alamos National Laboratory SAVY-4000 Field Surveillance Plan Update for 2016

International Nuclear Information System (INIS)

Kelly, Elizabeth J.; Stone, Timothy Amos; Smith, Paul Herrick; Prochnow, David Adrian; Weis, Eric M.

2016-01-01

developing the technical basis for a 40-year design life. The technical basis for the longer design life will be developed based on the results of this surveillance plan and the concurrent lifetime extension studies (Blair et al. 2012, Weis et al. 2015a). A long-term surveillance plan will be developed by the completion of this plan and will be based on the results of the first several years of this five-year surveillance plan and the lifetime extension studies. In addition, the current Hagan container population is so large (approximately 3,500 LANL-wide, approximately 3,000 in PF-4) that it is anticipated Hagan containers will be in use for many years to come. Therefore, this plan includes surveillance activities for the Hagan container system during the time it takes to replace the Hagan containers with manually-compliant containers such as the SAVY 4000. These Hagan examinations not only provide information to determine if additional Hagan surveillance is needed, but also support SAVY lifetime-extension studies because some of the container components are made from similar material (e.g., stainless steel and Viton).

High-potential Working Fluids for Next Generation Binary Cycle Geothermal Power Plants

Energy Technology Data Exchange (ETDEWEB)

Zia, Jalal [GE Global Research; Sevincer, Edip; Chen, Huijuan; Hardy, Ajilli; Wickersham, Paul; Kalra, Chiranjeev; Laursen, Anna Lis; Vandeputte, Thomas

2013-06-29

A thermo-economic model has been built and validated for prediction of project economics of Enhanced Geothermal Projects. The thermo-economic model calculates and iteratively optimizes the LCOE (levelized cost of electricity) for a prospective EGS (Enhanced Geothermal) site. It takes into account the local subsurface temperature gradient, the cost of drilling and reservoir creation, stimulation and power plant configuration. It calculates and optimizes the power plant configuration vs. well depth. Thus outputs from the model include optimal well depth and power plant configuration for the lowest LCOE. The main focus of this final report was to experimentally validate the thermodynamic properties that formed the basis of the thermo-economic model built in Phase 2, and thus build confidence that the predictions of the model could be used reliably for process downselection and preliminary design at a given set of geothermal (and/or waste heat) boundary conditions. The fluid and cycle downselected was based on a new proprietary fluid from a vendor in a supercritical ORC cycle at a resource condition of 200°C inlet temperature. The team devised and executed a series of experiments to prove the suitability of the new fluid in realistic ORC cycle conditions. Furthermore, the team performed a preliminary design study for a MW-scale turbo expander that would be used for a supercritical ORC cycle with this new fluid. The following summarizes the main findings in the investigative campaign that was undertaken: 1. Chemical compatibility of the new fluid with common seal/gasket/Oring materials was found to be problematic. Neoprene, Viton, and silicone materials were found to be incompatible, suffering chemical decomposition, swelling and/or compression set issues. Of the materials tested, only TEFLON was found to be compatible under actual ORC temperature and pressure conditions. 2. Thermal stability of the new fluid at 200°C and 40 bar was found to be acceptable after 399

Development of Long-Lifetime Pulsed Gas Valves for Pulsed Electric Thrusters

Science.gov (United States)

Burkhardt, Wendel M.; Crapuchettes, John M.; Addona, Brad M.; Polzin, Kurt A.

2015-01-01

even 10(exp 9) cycles is well above anything demonstrated, this lower value was selected as the design point for the present work. The valve seal must remain leak-tight throughout operation, and the body must maintain a low internal leakage at relatively high operating temperatures. The full set of design requirements used for this program are summarized in Table 1. In this work, we describe two pulsed gas valves that have been fabricated to have long lifetime and demonstrate the characteristics listed above. The first is a miniaturized, conventional electromagnet-based valve while the second is a piezoelectric-based valve design. The conventional valve, shown in Fig. 1, is opened by use of a solenoid electromagnetic actuator. When current is applied to the solenoid coil, magnetic forces pull the plunger away from the valve seat, allowing fluid to flow through the valve. Removal of electrical current permits the spring and fluid pressure to seat the plunger, halting the flow of fluid. The valve body is fabricated from 304L corrosion resistant steel (CRES) and while the parts that form the magnetic circuit are fabricated from 430 CRES. This material does not have optimum magnetic properties, but its corrosion resistance permits incorporation into a design without requiring an additional plating process. A viton O-ring compound (Parker V0884-75), selected for its mechanical strength at elevated temperatures, was used for the valve seat seal. The design was based solely on the use of analytical sizing calculations, as opposed to a more rigorous finite element analysis. While this valve is small and relatively lightweight, it does not represent a design that is optimized for mass and/or a given volume envelope. The piezoelectric valve is a "puller" valve design. Applying a voltage to the piezo crystal causes it to elongate and pull a pintle off the seat, opening the valve. The valve seal consists of the pintle with an external, spherically-formed tip fabricated from