Prolonged fasting activates Nrf2 in post-weaned elephant seals.

Science.gov (United States)

Vázquez-Medina, José Pablo; Soñanez-Organis, José G; Rodriguez, Ruben; Viscarra, Jose A; Nishiyama, Akira; Crocker, Daniel E; Ortiz, Rudy M

2013-08-01

Elephant seals naturally experience prolonged periods of absolute food and water deprivation (fasting). In humans, rats and mice, prolonged food deprivation activates the renin-angiotensin system (RAS) and increases oxidative damage. In elephant seals, prolonged fasting activates RAS without increasing oxidative damage likely due to an increase in antioxidant defenses. The mechanism leading to the upregulation of antioxidant defenses during prolonged fasting remains elusive. Therefore, we investigated whether prolonged fasting activates the redox-sensitive transcription factor Nrf2, which controls the expression of antioxidant genes, and if such activation is potentially mediated by systemic increases in RAS. Blood and skeletal muscle samples were collected from seals fasting for 1, 3, 5 and 7 weeks. Nrf2 activity and nuclear content increased by 76% and 167% at week 7. Plasma angiotensin II (Ang II) and transforming growth factor β (TGF-β) were 5000% and 250% higher at week 7 than at week 1. Phosphorylation of Smad2, an effector of Ang II and TGF signaling, increased by 120% at week 7 and by 84% in response to intravenously infused Ang II. NADPH oxidase 4 (Nox4) mRNA expression, which is controlled by smad proteins, increased 430% at week 7, while Nox4 protein expression, which can activate Nrf2, was 170% higher at week 7 than at week 1. These results demonstrate that prolonged fasting activates Nrf2 in elephant seals and that RAS stimulation can potentially result in increased Nox4 through Smad phosphorylation. The results also suggest that Nox4 is essential to sustain the hormetic adaptive response to oxidative stress in fasting seals.

Cover-gas-seal component development: dynamic inflatable-plug seal improvement

International Nuclear Information System (INIS)

Horton, P.H.

1977-01-01

This report documents the 1) radial compliance and 2) low friction coating tests conducted on the CRBRP Rotating Plug Inflatable Seals per test plan N707TR810014. Test results show that narrowing the seal blade from 0.25 to 0.12 in. will effectively reduce dynamic drag from 30 to 20 lb/ft under nominal conditions and will increase seal radial compliance from 0.12 to 0.30 in. without an unacceptable rise in dynamic drag. Tests also demonstrated that application of a teflon coating to the seal wear surface reduced breakaway drag by 25% based on results of comparison dwells

Geological conditions for lateral sealing of active faults and relevant research methods

Directory of Open Access Journals (Sweden)

Guang Fu

2017-01-01

Full Text Available Many researchers worked a lot on geologic conditions for lateral sealing of faults, but none of their studies took the effect of internal structures of fault zones on the lateral sealing capacity of faults. Therefore, the lateral sealing of active faults has rarely been discussed. In this paper, based on the analysis of the composition and structure characteristics of fault fillings, the geological conditions for lateral sealing of active faults and relevant research method were discussed in reference to the lateral sealing mechanisms of inactive fault rocks. It is shown that, in order to satisfy geologically the lateral sealing of active faults, the faults should be antithetic and the faulted strata should be mainly composed of mudstone, so that the displacement pressure of fault fillings is higher than or equal to that of reservoir rocks in oil and gas migration block. Then, a research method for the lateral sealing of active faults was established by comparing the displacement pressure of fillings in the fault with that of reservoir rocks in oil and gas migration block. This method was applied to three antithetic faults (F1, F2 and F3 in No. 1 structure of the Nanpu Sag, Bohai Bay Basin. As revealed, the fillings of these three active faults were mostly argillaceous at the stage of natural gas accumulation (the late stage of Neogene Minghuazhen Fm sedimentation, and their displacement pressures were higher than that of reservoir rocks in the first member of Paleogene Dongying Fm (F1 and F3 and the Neogene Guantao Fm (F2. Accordingly, they are laterally sealed for natural gas, which is conducive to the accumulation and preservation of natural gas. Industrial gas flow has been produced from the first member of Paleogene Dongying Fm in Well Np101, the Guantao Fm in Well Np1-2 and the first member of Paleogene Dongying Fm in Well Np1, which is in agreement with the analysis result. It is verified that this method is feasible for investigating the

Cover-gas seals: 11-LMFBR seal-test program

International Nuclear Information System (INIS)

Steele, O.P. III; Horton, P.H.

1977-01-01

The objective of the Cover Gas Seal Material Development Program is to perform the engineering development required to provide reliable seals for LMFBR application. Specific objectives are to verify the performance of commercial solid cross-section and inflatable seals under reactor environments including radiation, to develop advanced materials and configurations capable of achieving significant improvement in radioactive gas containment and seal temperature capabilities, and to optimize seal geometry for maximum reliability and minimal gas permeation

Critical element development of double seal door for tritium containment

International Nuclear Information System (INIS)

Kanamori, Naokazu; Kakudate, Satoshi; Oka, Kiyoshi; Nakahira, Masataka; Taguchi, Kou; Obara, Kenjiro; Tada, Eisuke; Shibanuma, Kiyoshi; Seki, Masahiro

1994-08-01

In fusion experimental reactors, the in-vessel components such as blanket are activated due to D-T operation and they have to be assembled and replaced by remote operation through port penetration of plasma vacuum vessel. A double seal door is inevitably required at an interface between vacuum vessel port and maintenance cask in order to avoid the dispersion of tritium and activated dust during in-vessel component handling. The double seal door should have two open/close doors with four seal surfaces so as to keep leak tightness both of the vacuum vessel and the maintenance cask when doors closed, and to provide access space for handling in-vessel components when doors opened. A prototype compact double seal door with an attractive kinematics of parabolic trajectory has been proposed so as to minimize dead space for the door open/close operation, compared with ordinary slide or hinge type door. Based on this design concept, a sub-scaled model of double seal door with trapezoidal cross-section of around 0.2 m 2 has been fabricated. Through the preliminary experiments such as open/close performance, the double seal door mechanism with parabolic trajectory has been successfully demonstrated. As for leak tightness, seal characteristics of a polyimide ring irradiated up to 10 MGy have been measured. (author)

TECHNOLOGY ROADMAPPING FOR IAEA SEALS.

Energy Technology Data Exchange (ETDEWEB)

HOFFHEINS,B.; ANNESE,C.; GOODMAN,M.; OCONNOR,W.; GUSHUE,S.; PEPPER,S.

2003-07-13

In the fall of 2002, the U.S. Support Program (USSP) initiated an effort to define a strategy or ''roadmap'' for future seals technologies and to develop a generalized process for planning safeguards equipment development, which includes seals and other safeguards equipment. The underlying objectives of the USSP include becoming more proactive than reactive in addressing safeguards equipment needs, helping the IAEA to maintain an inventory of cost-effective, reliable, and effective safeguards equipment, establishing a long-term planning horizon, and securing IAEA ownership in the process of effective requirements definition and timely transitioning of new or improved systems for IAEA use. At an initial workshop, seals, their functions, performance issues, and future embodiments were discussed in the following order: adhesive seals, metal seals, passive and active loop seals, ultrasonic seals, tamper indicating enclosures (including sample containers, equipment enclosures, and conduits). Suggested improvements to these technologies focused largely on a few themes: (1) The seals must be applied quickly, easily, and correctly; (2) Seals and their associated equipment should not unduly add bulk or weight to the inspectors load; (3) Rapid, in-situ verifiability of seals is desirable; and (4) Seal systems for high risk or high value applications should have two-way, remote communications. Based upon these observations and other insights, the participants constructed a skeletal approach for seals technology planning. The process begins with a top-level review of the fundamental safeguards requirements and extraction of required system features, which is followed by analysis of suitable technologies and identification of technology gaps, and finally by development of a planning schedule for system improvements and new technology integration. Development of a comprehensive procedure will require the partnership and participation of the IAEA. The

Development on application of ultrasonic sealing techniques to plutonium transportation cask

International Nuclear Information System (INIS)

Hayakawa, Tsuyoshi; Akiba, Mitsunori; D'Agraives, B.C.

1994-01-01

In a cooperation research between Power Reactor and Nuclear Fuel Development Corporation and Commission of the European Communities, Joint Research Centre, Ispra establishment, application of ultrasonic sealing techniques to a plutonium container is developed in Ispra. The seal is derived from the sealing-bolt technology currently in use at the BNFL site of sellafield (UK) for the safeguarding of underwater spent fuel storage containers called MEBs. In this technique, one of the normal bolts closing the lid of the container is replaced by a special ultrasonically verifiable sealing-bolt. In the application to the plutonium container, it is proposed to attach a clamping seal which has the same internal configuration as a MEB sealing-bolt but is fastened with a 'one-way' mechanism to one of the protruding pins of the container. Similarly the seal is provided with an identity and integrity features. The uniqueness of the identity, as well as the integrity can be checked on the spot by an inspector carrying a reading equipment. Thus, in a few minutes, one identifies the seal and knows whether its integrity is intact, which tells that the container has not been opened or attempted to open illeagally. By application of the seal to the plutonium container, the containment/surveillance during the transportation will be upgraded. (author)

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

ITER lip seal welding and cutting developments

Energy Technology Data Exchange (ETDEWEB)

Levesy, B.; Cordier, J.J.; Jokinen, T. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Kujanpää, V.; Karhu, M. [VTT Technical Research Centre of Finland (Finland); Le Barbier, R. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Määttä, T. [VTT Technical Research Centre of Finland (Finland); Martins, J.P.; Utin, Y. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

2015-10-15

Highlights: • Different TIG and Laser welding techniques are tested. • Twin spot laser welding techniques is the best. • Limited heat input gives a stable weld pool in all positions. • Penetrations is achieved. • Lip seal welding and cutting with a robotic arm is successfully performed on a representative mock-up. - Abstract: The welded lip seals form part of the torus primary vacuum boundary in between the port plugs and the vacuum vessel, and are classified as Protection Important Component. In order to refurbish the port plugs or the in-vessel components, port plugs have to be removed from the machine. The lip seal design must enable up to ten opening of the vacuum vessel during the life time operation of the ITER machine. Therefore proven, remote reliable cutting and re-welding are essential, as these operations need to be performed in the port cells in a nuclear environment, where human presence will be restricted. Moreover, the combination of size of the components to be welded (∼10 m long vacuum compatible thin welds) and the congested environment close to the core of the machine constraint the type and size of tools to be used. This paper describes the lip seal cutting and welding development programme performed at the VTT Technical Research Centre, Finland. Potential cutting and welding techniques are analyzed and compared. The development of the cutting, TIG and laser welding techniques on samples are presented. Effects of lip seal misalignments and optimization of the 2 welding processes are discussed. Finally, the manufacturing and test of the two 1.2 m × 1 m representative mock-ups are presented. The set-up and use of a robotic arm for the mock-up cutting and welding operations are also described.

ITER lip seal welding and cutting developments

International Nuclear Information System (INIS)

Levesy, B.; Cordier, J.J.; Jokinen, T.; Kujanpää, V.; Karhu, M.; Le Barbier, R.; Määttä, T.; Martins, J.P.; Utin, Y.

2015-01-01

Highlights: • Different TIG and Laser welding techniques are tested. • Twin spot laser welding techniques is the best. • Limited heat input gives a stable weld pool in all positions. • Penetrations is achieved. • Lip seal welding and cutting with a robotic arm is successfully performed on a representative mock-up. - Abstract: The welded lip seals form part of the torus primary vacuum boundary in between the port plugs and the vacuum vessel, and are classified as Protection Important Component. In order to refurbish the port plugs or the in-vessel components, port plugs have to be removed from the machine. The lip seal design must enable up to ten opening of the vacuum vessel during the life time operation of the ITER machine. Therefore proven, remote reliable cutting and re-welding are essential, as these operations need to be performed in the port cells in a nuclear environment, where human presence will be restricted. Moreover, the combination of size of the components to be welded (∼10 m long vacuum compatible thin welds) and the congested environment close to the core of the machine constraint the type and size of tools to be used. This paper describes the lip seal cutting and welding development programme performed at the VTT Technical Research Centre, Finland. Potential cutting and welding techniques are analyzed and compared. The development of the cutting, TIG and laser welding techniques on samples are presented. Effects of lip seal misalignments and optimization of the 2 welding processes are discussed. Finally, the manufacturing and test of the two 1.2 m × 1 m representative mock-ups are presented. The set-up and use of a robotic arm for the mock-up cutting and welding operations are also described.

Development and application of test apparatus for classification of sealed source

International Nuclear Information System (INIS)

Kim, Dong Hak; Seo, Ki Seog; Bang, Kyoung Sik; Lee, Ju Chan; Son, Kwang Je

2007-01-01

Sealed sources have to conducted the tests be done according to the classification requirements for their typical usages in accordance with the relevant domestic notice standard and ISO 2919. After each test, the source shall be examined visually for loss of integrity and pass an appropriate leakage test. Tests to class a sealed source are temperature, external pressure, impact, vibration and puncture test. The environmental test conditions for tests with class numbers are arranged in increasing order of severity. In this study, the apparatus of tests, except the vibration test, were developed and applied to three kinds of sealed source. The conditions of the tests to class a sealed source were stated and the difference between the domestic notice standard and ISO 2919 were considered. And apparatus of the tests were made. Using developed apparatus we conducted the test for 192 Ir brachytherapy sealed source and two kinds of sealed source for industrial radiography. 192 Ir brachytherapy sealed source is classified by temperature class 5, external pressure class 3, impact class 2 and vibration and puncture class 1. Two kinds of sealed source for industrial radiography are classified by temperature class 4, external pressure class 2, impact and puncture class 5 and vibration class 1. After the tests, Liquid nitrogen bubble test and vacuum bubble test were done to evaluate the safety of the sealed sources

Avoidance of wind farms by harbour seals is limited to pile driving activities.

Science.gov (United States)

Russell, Debbie J F; Hastie, Gordon D; Thompson, David; Janik, Vincent M; Hammond, Philip S; Scott-Hayward, Lindesay A S; Matthiopoulos, Jason; Jones, Esther L; McConnell, Bernie J

2016-12-01

As part of global efforts to reduce dependence on carbon-based energy sources there has been a rapid increase in the installation of renewable energy devices. The installation and operation of these devices can result in conflicts with wildlife. In the marine environment, mammals may avoid wind farms that are under construction or operating. Such avoidance may lead to more time spent travelling or displacement from key habitats. A paucity of data on at-sea movements of marine mammals around wind farms limits our understanding of the nature of their potential impacts.Here, we present the results of a telemetry study on harbour seals Phoca vitulina in The Wash, south-east England, an area where wind farms are being constructed using impact pile driving. We investigated whether seals avoid wind farms during operation, construction in its entirety, or during piling activity. The study was carried out using historical telemetry data collected prior to any wind farm development and telemetry data collected in 2012 during the construction of one wind farm and the operation of another.Within an operational wind farm, there was a close-to-significant increase in seal usage compared to prior to wind farm development. However, the wind farm was at the edge of a large area of increased usage, so the presence of the wind farm was unlikely to be the cause.There was no significant displacement during construction as a whole. However, during piling, seal usage (abundance) was significantly reduced up to 25 km from the piling activity; within 25 km of the centre of the wind farm, there was a 19 to 83% (95% confidence intervals) decrease in usage compared to during breaks in piling, equating to a mean estimated displacement of 440 individuals. This amounts to significant displacement starting from predicted received levels of between 166 and 178 dB re 1 μPa (p-p) . Displacement was limited to piling activity; within 2 h of cessation of pile driving, seals were distributed as

Development of an externally controllable sealed isotope generator.

Science.gov (United States)

Sasaki, Toru; Aoki, Katsumi; Yamashita, Ryosuke; Hori, Kensuke; Kato, Taiga; Saito, Misaki; Niisawa, Kazuhiro; Nagatsu, Kotaro; Nozaki, Tadashi

2018-03-01

An externally controllable sealed isotope generator has been proposed for radiation education activities. Column ( 68 Ge- 68 Ga and 137 Cs- 137m Ba) and solvent extraction ( 68 Ge- 68 Ga)-based isotope generators were applied as radioactive sources. These generators showed high milking efficiencies and low breakthrough after repeated uses, and are expected to promote the use of isotope generators without radioactive contamination or the emission of radioactive waste. This isotope generator provides a new concept for sealed radioisotope sources. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of a sealed-accelerator-tube neutron generator

Science.gov (United States)

Verbeke; Leung; Vujic

2000-10-01

Sealed-accelerator-tube neutron generators are being developed in Lawrence Berkeley National Laboratory (LBNL) for applications ranging from neutron radiography to boron neutron capture therapy and neutron activation analysis. The new generation of high-output neutron generators is based on the D-T fusion reaction, producing 14.1-MeV neutrons. The main components of the neutron tube--the ion source, the accelerator and the target--are all housed in a sealed metal container without external pumping. Thick-target neutron yield computations are performed in this paper to estimate the neutron yield of titanium and scandium targets. With an average deuteron beam current of 1 A and an energy of 120 keV, a time-averaged neutron production of approximately 10(14) n/s can be estimated for a tritiated target, for both pulsed and cw operations. In mixed deuteron/triton beam operation, a beam current of 2 A at 150 keV is required for the same neutron output. Recent experimental results on ion sources and accelerator columns are presented and discussed.

Inflatable Module Seal Interface Development and Testing

Data.gov (United States)

National Aeronautics and Space Administration — Develop a repeatable low permeable sealing interface evaluating O-ring, RTV bond and flowed RTV bond methods. Advanced Bladder materials (ArmorFlex, Nanoclay, etc)...

Ceramic Seal.

Energy Technology Data Exchange (ETDEWEB)

Smartt, Heidi A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Romero, Juan A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Custer, Joyce Olsen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hymel, Ross W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Krementz, Dan [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Gobin, Derek [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Harpring, Larry [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Martinez-Rodriguez, Michael [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Varble, Don [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); DiMaio, Jeff [Tetramer Technologies, Pendleton, SC (United States); Hudson, Stephen [Tetramer Technologies, Pendleton, SC (United States)

2016-11-01

Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

Ceramic Seal

International Nuclear Information System (INIS)

Smartt, Heidi A.; Romero, Juan A.; Custer, Joyce Olsen; Hymel, Ross W.; Krementz, Dan; Gobin, Derek; Harpring, Larry; Martinez-Rodriguez, Michael; Varble, Don; DiMaio, Jeff; Hudson, Stephen

2016-01-01

Containment/Surveillance (C/S) measures are critical to any verification regime in order to maintain Continuity of Knowledge (CoK). The Ceramic Seal project is research into the next generation technologies to advance C/S, in particular improving security and efficiency. The Ceramic Seal is a small form factor loop seal with improved tamper-indication including a frangible seal body, tamper planes, external coatings, and electronic monitoring of the seal body integrity. It improves efficiency through a self-securing wire and in-situ verification with a handheld reader. Sandia National Laboratories (SNL) and Savannah River National Laboratory (SRNL), under sponsorship from the U.S. National Nuclear Security Administration (NNSA) Office of Defense Nuclear Nonproliferation Research and Development (DNN R&D), have previously designed and have now fabricated and tested Ceramic Seals. Tests have occurred at both SNL and SRNL, with different types of tests occurring at each facility. This interim report will describe the Ceramic Seal prototype, the design and development of a handheld standalone reader and an interface to a data acquisition system, fabrication of the seals, and results of initial testing.

Development of simplified rotating plug seal structure

International Nuclear Information System (INIS)

Ueta, M.; Ichimiya, M.; Kanaoka, T.; Sekiya, H.; Ueda, S.; Ishibashi, S.

1991-01-01

We studied a compact and simplified rotating plug seal structure and conducted experiments for key elements of the concept such us the mechanical seal structure and sodium deposit prevention system. Good characteristics were confirmed for the mechanical seal structure, which utilizes an elastomer seal and thin lathe bearing. Applicability of the density barrier concept was also confirmed as the sodium deposit prevention system. This concept can be applied to actual plants. (author)

Glass sealing

Energy Technology Data Exchange (ETDEWEB)

Brow, R.K.; Kovacic, L.; Chambers, R.S. [Sandia National Labs., Albuquerque, NM (United States)

1996-04-01

Hernetic glass sealing technologies developed for weapons component applications can be utilized for the design and manufacture of fuel cells. Design and processing of of a seal are optimized through an integrated approach based on glass composition research, finite element analysis, and sealing process definition. Glass sealing procedures are selected to accommodate the limits imposed by glass composition and predicted calculations.

Sealing performance of a magnetic fluid seal for rotary blood pumps.

Science.gov (United States)

Mitamura, Yoshinori; Takahashi, Sayaka; Kano, Kentaro; Okamoto, Eiji; Murabayashi, Shun; Nishimura, Ikuya; Higuchi, Taka-Aki

2009-09-01

A magnetic fluid (MF) for a rotary blood pump seal enables mechanical contact-free rotation of the shaft and, hence, has excellent durability. The performance of a MF seal, however, has been reported to decrease in liquids. We have developed a MF seal that has a "shield" mechanism and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. Under the condition of continuous flow, the MF seal remained in perfect condition against a pressure of 298 mm Hg (pump flow rate: 3.96 L/min). The seal was also perfect against a pressure of 170 mm Hg in a continuous flow of 3.9 L/min for 275 days. We have developed a MF seal that works in liquid against clinically used pressures. The MF seal is promising as a shaft seal for rotary blood pumps.

Design of Active Magnetic Bearing Controllers for Rotors Subjected to Gas Seal Forces

DEFF Research Database (Denmark)

Lauridsen, Jonas Skjødt; Santos, Ilmar F.

2018-01-01

Proper design of feedback controllers is crucial for ensuring high performance of Active Magnetic Bearing (AMB) supported rotor dynamic systems. Annular seals in those systems can contribute with significant forces, which, in many cases, are hard to model in advance due to complex geometries...... of the seal and multiphase fluids. Hence, it can be challenging to design AMB controllers that will guarantee robust performance for these kinds of systems. This paper demonstrates the design, simulation and experimental results of model based controllers for AMB systems, subjected to dynamic seal forces....... The controllers are found using H-infinity - and µ synthesis and are based on a global rotor dynamic model in-which the seal coefficients are identified in-situ. The controllers are implemented in a rotor-dynamic test facility with two radial AMBs and one annular seal with an adjustable inlet pressure. The seal...

Cask systems development program seal technology

International Nuclear Information System (INIS)

Madsen, M.M.; Humphreys, D.L.; Edwards, K.R.

1991-01-01

General design or test performance requirements for radioactive materials (RAM) packages are specified in Title 10 of the US Code of Federal Regulations Part 71 (10 CFR 71). Seals that provide the containment system interface between the packaging body and the closure must function in both high- and low-temperature environments under dynamic and static conditions. Experiments were performed to characterize the performance of several seal materials at low temperatures. Helium leak tests on face seals were used to compare the materials. Materials tested include butyl, neoprene, ethylene propylene, fluorosilicone, silicone, Eypel, Kalrez, Teflon, fluorocarbon, and Teflon/silicone composites. Results show that the seal materials tested, with the exception of silicone S613-60, are not leak tight (1 x 10 -7 std cm 3 /s) at manufacturer low-temperature ratings

Development and high temperature sealing performance study of double sealing flange

International Nuclear Information System (INIS)

Zhang Qinhua; Fu Yuan; Xie Leidong; Li Zhong; Tang Zhongfeng

2013-01-01

Background: Flange is an important component used in the connection between pipes or between pipe and equipment. It is widely used in mechanical industry, petrochemical industry and nuclear industry. Ordinary flange could be oxidized oi corroded under high temperature and strong corrosion condition, which leads to flange's failure. Purpose: The aim is to design and validate the double sealing flange which could be used in high temperature and strong corrosion condition stably and supplied as a reliable detachable connection for petrochemical industry and nuclear industry under high temperature and strong corrosion environment. Methods: New flange is designed using flexible graphite spiral wound gaskets and C style metal ring double sealing structure. The unique protection gas design ensures the graphite spiral wound gasket used in high temperature reliably. Test bed is built to verify the stability of the flange. Results: Pressure reducing of graphite spiral wound gasket is only 0.01 MPa at 750℃, 0.7 MPa for 43 h, there is not obvious oxidation phenomenon at the same time. The leakage rate of metal C sealing ring is 11.51×10 -4 atm cc/s, and the metal C ring sealing's performance meets the engineering requirements. Conclusion: The leakage rate of double sealing flange is almost zero under 0.7 MPa at 750℃, which meets the engineering requirements. It avoids oxidizing at high temperature and corroding under strong corrosion condition. (authors)

Soil seal development under simulated rainfall: Structural, physical and hydrological dynamics

Science.gov (United States)

Armenise, Elena; Simmons, Robert W.; Ahn, Sujung; Garbout, Amin; Doerr, Stefan H.; Mooney, Sacha J.; Sturrock, Craig J.; Ritz, Karl

2018-01-01

This study delivers new insights into rainfall-induced seal formation through a novel approach in the use of X-ray Computed Tomography (CT). Up to now seal and crust thickness have been directly quantified mainly through visual examination of sealed/crusted surfaces, and there has been no quantitative method to estimate this important property. X-ray CT images were quantitatively analysed to derive formal measures of seal and crust thickness. A factorial experiment was established in the laboratory using open-topped microcosms packed with soil. The factors investigated were soil type (three soils: silty clay loam - ZCL, sandy silt loam - SZL, sandy loam - SL) and rainfall duration (2-14 min). Surface seal formation was induced by applying artificial rainfall events, characterised by variable duration, but constant kinetic energy, intensity, and raindrop size distribution. Soil porosities derived from CT scans were used to quantify the thickness of the rainfall-induced surface seals and reveal temporal seal micro-morphological variations with increasing rainfall duration. In addition, the water repellency and infiltration dynamics of the developing seals were investigated by measuring water drop penetration time (WDPT) and unsaturated hydraulic conductivity (Kun). The range of seal thicknesses detected varied from 0.6 to 5.4 mm. Soil textural characteristics and OM content played a central role in the development of rainfall-induced seals, with coarser soil particles and lower OM content resulting in thicker seals. Two different trends in soil porosity vs. depth were identified: i) for SL soil porosity was lowest at the immediate soil surface, it then increased constantly with depth till the median porosity of undisturbed soil was equalled; ii) for ZCL and SL the highest reduction in porosity, as compared to the median porosity of undisturbed soil, was observed in a well-defined zone of maximum porosity reduction c. 0.24-0.48 mm below the soil surface. This

Numerical Investigation of the Effect of Radial Lip Seal Geometry on Sealing Performance

Science.gov (United States)

Tok, G.; Parlar, Z.; Temiz, V.

2018-01-01

Sealing elements are often needed in industry and especially in machine design. With the change and development of machine technology from day to day, sealing elements show continuous development and change in parallel with these developments. Many factors influence the performance of the sealing elements such as shaft surface roughness, radial force, lip geometry etc. In addition, the radial lip seals must have a certain pre-load and interference in order to provide a good sealing. This also affects the friction torque. Researchers are developing new seal designs to reduce friction losses in mechanical systems. In the presented study, the effect of the lip seal geometry on sealing performance will be examined numerically. The numerical model created for this purpose will be verified with experimental data firstly. In the numerical model, shaft and seal will be modeled as hyper-elastic in 2D and 3D. NBR (Nitrile Butadiene Rubber) as seal material will be analyzed for the rotating shaft state at constant speed by applying a uniform radial force.

Cover gas seals: FFTF-LMFBR seal test program

International Nuclear Information System (INIS)

Kurzeka, W.; Oliva, R.; Welch, T.S.; Shimazaki, T.

1974-01-01

The objectives of this program are to: (1) conduct static and dynamic tests to demonstrate or determine the mechanical performance of full-size (cross section) FFTF fuel transfer machine and reactor vessel head seals intended for use in a sodium vapor-inert gas environment, (2) demonstrate that these FFTF seals or new seal configurations provide acceptable fission product and cover gas retention capabilities at Clinch River Breeder Reactor Plant (CRBRP) operating environmental conditions other than radiation, and (3) develop improved seals and seal technology for the CRBRP to support the national objective to reduce all atmospheric contaminations to low levels

Development of Hermetic Sealing Glasses for Solid Oxide Fuel Cells, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Sealing glasses, either rigid glass-ceramics or viscous, non-crystallizing compositions, will be developed and sealing processes will be optimized based on NASA's...

Development of quality assurance procedures for production of sealed radiation source

CERN Document Server

Nam, J H; Cho, W K; Han, H S; Hong, S B; Kim, K H; Kim, S D; Lee, Y G; Lim, N J

2001-01-01

The quality assurance procedures for sealed radiation sources production using HANARO and RIPF have been developed. The detailed quality assurance procedures are essential to manage the whole work process effectively and ensure the quality of the produced sealed sources. Through applying this quality assurance procedures to the entire production works of the sealed radiation sources, it is expected that the quality of the products, the safety of the works and the satisfaction of the customers will be increased.

Development of methodology for the characterization of radioactive sealed sources

International Nuclear Information System (INIS)

Ferreira, Robson de Jesus

2010-01-01

Sealed radioactive sources are widely used in many applications of nuclear technology in industry, medicine, research and others. The International Atomic Energy Agency (IAEA) estimates tens of millions sources in the world. In Brazil, the number is about 500 thousand sources, if the Americium-241 sources present in radioactive lightning rods and smoke detectors are included in the inventory. At the end of the useful life, most sources become disused, constitute a radioactive waste, and are then termed spent sealed radioactive sources (SSRS). In Brazil, this waste is collected by the research institutes of the Nuclear Commission of Nuclear Energy and kept under centralized storage, awaiting definition of the final disposal route. The Waste Management Laboratory (WML) at the Nuclear and Energy Research Institute is the main storage center, having received until July 2010 about 14.000 disused sources, not including the tens of thousands of lightning rod and smoke detector sources. A program is underway in the WML to replacing the original shielding by a standard disposal package and to determining the radioisotope content and activity of each one. The identification of the radionuclides and the measurement of activities will be carried out with a well type ionization chamber. This work aims to develop a methodology for measuring or to determine the activity SSRS stored in the WML accordance with its geometry and determine their uncertainties. (author)

Development of an improved low profile hub seal refurbishment tool

International Nuclear Information System (INIS)

Wagg, L.

1997-01-01

The hub seal area of a fuel channel feeder coupling can be exposed to oxygen in the atmosphere if protective measures are not taken during maintenance outages. Exposure to oxygen can lead to pitting of the hub seal area. Although this is a rare occurrence, the resulting possibility of the feeder coupling leakage led to the development of a feeder hub refurbishment tool. To reduce time and man-rem exposure during feeder hub seal refurbishment, an improved low profile hub seat refurbishing tool has been developed. The improved tool design will allow for quick and controlled removal of material, and the restoration of a roll-burnished finish equivalent to the original requirements. The new tool can be used in maintenance operations, with the end fitting present, as well as under retube-type circumstances, with the end fitting removed. (author)

Seals and sealing handbook

CERN Document Server

Flitney, Robert K

2014-01-01

Seals and Sealing Handbook, 6th Edition provides comprehensive coverage of sealing technology, bringing together information on all aspects of this area to enable you to make the right sealing choice. This includes detailed coverage on the seals applicable to static, rotary and reciprocating applications, the best materials to use in your sealing systems, and the legislature and regulations that may impact your sealing choices. Updated in line with current trends this updated reference provides the theory necessary for you to select the most appropriate seals for the job and with its 'Failur

Active bypass flow control for a seal in a gas turbine engine

Science.gov (United States)

Ebert, Todd A.; Kimmel, Keith D.

2017-01-10

An active bypass flow control system for controlling bypass compressed air based upon leakage flow of compressed air flowing past an outer balance seal between a stator and rotor of a first stage of a gas turbine in a gas turbine engine is disclosed. The active bypass flow control system is an adjustable system in which one or more metering devices may be used to control the flow of bypass compressed air as the flow of compressed air past the outer balance seal changes over time as the outer balance seal between the rim cavity and the cooling cavity wears. In at least one embodiment, the metering device may include a valve formed from one or more pins movable between open and closed positions in which the one pin at least partially bisects the bypass channel to regulate flow.

Design, development and deployment of special sealing plug for 540 MWe PHWRs

International Nuclear Information System (INIS)

Sharma, G.; Roy, S.; Patel, R.J.

2012-01-01

The coolant channel in Pressurized Heavy Water Reactors is a pressure boundary component and is very important for reactor performance and reactor safety. Monitoring the condition of the pressure tube of each coolant channel on a periodic basis is very important. In-Service Inspection (ISI) of the coolant channels in water filled condition is done regularly for 220 MWe PHWR. For the same purpose BARC Channel Inspection System is developed for 540 MWe PHWR also. Special Sealing Plug has been developed to facilitate the channel inspection (in water filled condition) with all necessary safety features at par with normal sealing plug. Special Sealing Plug provides a 50 mm through hole for passage of drive tube of Inspection Head maintaining integrity of PHT. Lot of challenges were faced for developing the Special Sealing Plug and its associated tools. It was a first of its kind design. First ISI of TAPS-4 was conducted successfully using this plug along with associated tools in November 2011. This development has provided immense help to NPCIL in life management of 540 MWe PHWR coolant channels. (author)

ReflectoActive(trademark) Seals for Materials Control and Accountability

International Nuclear Information System (INIS)

Richardson, G.D.; Younkin, J.R.; Bell, Z.W.

2002-01-01

The ReflectoActive(trademark) Seals system, a continuously monitored fiber optic, active seal technology, provides real-time tamper indication for large arrays of storage containers. The system includes a PC running the RFAS software, an Immediate Detection Unit (IDU), an Optical Time Domain Reflectometer (OTDR), links of fiber optic cable, and the methods and devices used to attach the fiber optic cable to the containers. When a breach on any of the attached fiber optic cable loops occurs, the IDU immediately signals the connected computer to control the operations of an OTDR to seek the breach location. The ReflectoActive(trademark) Seals System can be adapted for various types of container closure designs and implemented in almost any container configuration. This automatic protection of valued assets can significantly decrease the time and money required for surveillance. The RFAS software is the multi-threaded, client-server application that monitors and controls the components of the system. The software administers the security measures such as a two-person rule as well as continuous event logging. Additionally the software's architecture provides a secure method by which local or remote clients monitor the system and perform administrative tasks. These features provide the user with a robust system to meet today's material control and accountability needs. A brief overview of the hardware, and different hardware configurations will be given. The architecture of the system software, and its benefits will then be discussed. Finally, the features to be implemented in future versions of the system will be presented

Design and Test of an Event Detector and Locator for the ReflectoActive Seals System

International Nuclear Information System (INIS)

Stinson, Brad J.

2006-01-01

The purpose of this work was to research, design, develop and test a novel instrument for detecting fiber optic loop continuity and spatially locating fiber optic breaches. The work is for an active seal system called ReflectoActive(trademark) Seals whose purpose is to provide real time container tamper indication. A Field Programmable Gate Array was used to implement a loop continuity detector and a spatial breach locator based on a high acquisition speed single photon counting optical time domain reflectometer. Communication and other control features were added in order to create a usable instrument that met defined requirements. A host graphical user interface was developed to illustrate system use and performance. The resulting device meets performance specifications by exhibiting a dynamic range of 27dB and a spatial resolution of 1.5 ft. The communication scheme used expands installation options and allows the device to communicate to a central host via existing Local Area Networks and/or the Internet.

Development of a low-permeability glass--ceramic to seal to molybdenum

International Nuclear Information System (INIS)

Eagan, R.J.

1975-03-01

This report describes the development of low-permeability glass-ceramics which can be sealed directly to molybdenum for the purpose of producing long-life vacuum tubes. Low permeability to helium and thermal expansion match to molybdenum are the bases upon which particular glass-ceramic compositions were selected and developed. The fabrication of tube envelopes using glass-ceramics is simplified when compared to conventional ceramic/metal tubes and these melting and sealing techniques are presented

Design optimization of seal structure for sealing liquid by magnetic fluids

International Nuclear Information System (INIS)

Liu Tonggang; Cheng Yusheng; Yang Zhiyi

2005-01-01

The durability of the magnetic fluid seal clearly decreases when sealing another liquid because of the interface instability caused by the applied magnetic field and the velocity difference of the two liquids. With an intention to establish a stable interface during sealing liquid, a new magnetic fluid seal was developed in this paper. The parameters of the structure were optimized by a simulation apparatus. And the magnetic fluid seal designed based on the optimum parameters shows good performance and long life for sealing lubricating oil

Development of radioactive sealed sources in epoxy matrix

International Nuclear Information System (INIS)

Benega, Marcos A.G.; Nagatomi, Helio R.; Rostelato, Maria Elisa C.M.; Karan Junior, Dib; Souza, Carla D.; Tiezzi, Rodrigo; Rodrigues, Bruna T.; Peleias Junior, Fernando S.

2013-01-01

The aim of the present work is to study and develop commercial resins for manufacturing solid sealed sources. The sources are produced with radionuclides of barium-133, cesium-137 and cobalt-57. They are used in radiation detectors verification. For the immobilization of the radionuclides in the epoxy matrix, it is made use of emulsifying agents that ensure the miscibility between resin and aqueous radioactive solution, as well as curing agents for controlling, curing and sealing the standard radioactive solution completely. As a result, it is expected to obtain standard sealed sources and equivalent to water. The equivalence to water is an important and necessary characteristic. The radioisotopes used in nuclear medicine are supplied in an aqueous form and the resin applied must have a very similar density comparing to the water. The sources must also be comparable in quality to sources produced internationally, but with low cost and wide available materials in the market. It is intended to create a national technology able to meet the demand of this product in the domestic market and achieve excellence in quality through accreditation and certification of the product by the appropriate agencies. The study of the necessary parameters used in the production of these sources, will bring technology for the manufacture of other categories of standard sealed sources, those used for nuclear medicine, image, laboratories and industry. (author)

VAK III. Seals and sealing system

International Nuclear Information System (INIS)

d'Agraives, B.C.; Dal Cero, G.; Debeir, R.; Mascetti, E.; Toornvliet, J.; Volcan, A.

1986-01-01

This report presents the VAK III seals and sealing system, which have been used over a period of two years at the Kahl nuclear facility (Federal Republic of Germany), where field tests and feasibility studies were conducted in order to offer a possible solution for the sealing of LWR fuel assemblies. It has been prepared with the aim of an assessment study to be done at the IAEA. It gives all characteristics and technical descriptions for: the sealing principle, the seal construction, the operating tools, the data processing, the drawings, the publications related to that seal. The main points of progress are: the Strong Random Internal Defects (STRID) incorporated in the seals, allowing the obtention of a good signature stability; the Integrity Check on the Seal Status (broken or not) obtained through a decisive mechanical improvement: the Double Breakage Integrity Check (DOBRIC) and with a better ultrasonic evidence of that status; the provision of new function tools, allowing the performance of Identity Measurements in dry conditions (which means also at the manufacturer plant) or in deeper water (wet storage); the study and development of a new JRC VAK 45 Compact Instrument Box, in which all the measuring functions can be grouped and incorporating an autonomous Minicomputer offering to the Inspection the possibility of performing, on the spot, Correlation and Decision processes. The general benefit of such a feasibility study should be to convince the potential users that such a Safeguards Sealing System can be studied for slightly - or largely - different other applications, provided that the Basic and Operating Functions required to the system be clearly defined, possibly after a common agreement would be stated

Development of new design mechanical seal tester for Primary Loop Recirculation Pump (PLR Pump)

International Nuclear Information System (INIS)

Fukushima, Naoki; Koshiba, Koremutsu

1995-01-01

The mechanical seal for a Primary Loop Recirculation Pump (PLR Pump) is an important part of a BWR plant. This study describes a new mechanical seal tester developed to certify mechanical seal performance before installation in a PLR Pump on site. (author)

Closure and Sealing Design Calculation

International Nuclear Information System (INIS)

T. Lahnalampi; J. Case

2005-01-01

The purpose of the ''Closure and Sealing Design Calculation'' is to illustrate closure and sealing methods for sealing shafts, ramps, and identify boreholes that require sealing in order to limit the potential of water infiltration. In addition, this calculation will provide a description of the magma that can reduce the consequences of an igneous event intersecting the repository. This calculation will also include a listing of the project requirements related to closure and sealing. The scope of this calculation is to: summarize applicable project requirements and codes relating to backfilling nonemplacement openings, removal of uncommitted materials from the subsurface, installation of drip shields, and erecting monuments; compile an inventory of boreholes that are found in the area of the subsurface repository; describe the magma bulkhead feature and location; and include figures for the proposed shaft and ramp seals. The objective of this calculation is to: categorize the boreholes for sealing by depth and proximity to the subsurface repository; develop drawing figures which show the location and geometry for the magma bulkhead; include the shaft seal figures and a proposed construction sequence; and include the ramp seal figure and a proposed construction sequence. The intent of this closure and sealing calculation is to support the License Application by providing a description of the closure and sealing methods for the Safety Analysis Report. The closure and sealing calculation will also provide input for Post Closure Activities by describing the location of the magma bulkhead. This calculation is limited to describing the final configuration of the sealing and backfill systems for the underground area. The methods and procedures used to place the backfill and remove uncommitted materials (such as concrete) from the repository and detailed design of the magma bulkhead will be the subject of separate analyses or calculations. Post-closure monitoring will not

Development of the DWPF canister temporary shrink-fit seal

International Nuclear Information System (INIS)

Kelker, J.W. Jr.

1986-04-01

The Defense Waste Processing Facility is being constructed at The Savannah River Plant for the containerization of high-level nuclear waste in a wasteform for eventual permanent disposal. The waste will be incorporated in molten glass and solidified in type 304L stainless steel canisters, 2-feet in diameter x 9-feet 10-inches long, containing a flanged 6-in.-diam pipe fill-nozzle. The canisters have a minimum wall thickness of 3/8 in. Utilizing the heat from the glass filling operation, a shrink-fit seal for a plug in the end of the canister fill nozzle was developed that: will withstand the radioactive environment; will prevent the spread of contamination, and will keep moisture and water from entering the canister during storage and decontamination of the canister by wet-frit blasting to remove smearable and oxide-film fixed radioactive nuclides; is removable and can be replaced by a new oversize plug in the event the seal fails the pressure decay leakage test ( -4 atm cc/sec helium); will keep the final weld closure clean and free of nuclear contamination; will withstand being pressed into the nozzle without exposing external contamination or completely breaking the seal; is reliable; and is easily installed. The seal consists of: a removable sleeve (with a tapered bore) which is shrink-fitted into the nozzle bore during canister fabrication; and a tapered plug which is placed into the sleeved nozzle after the canister is filled with radioactive molten glass. A leak-tight shrink-fit seal is formed between the nozzle, sleeve, and plug upon temperature equilibrium. The temporarily sealed canister is transferred from the Melt cell to the Decon cell, and the surface is decontaminated. Next it is transferred to the Weld/Test cell where the temporary seal is pressed down into the nozzle, revealing a clean cavity where the canister final closure weld is made

Active bypass flow control for a seal in a gas turbine engine

Science.gov (United States)

Ebert, Todd A.; Kimmel, Keith D.

2017-03-14

An active bypass flow control system for controlling bypass compressed air based upon leakage flow of compressed air flowing past an outer balance seal between a stator and rotor of a first stage of a gas turbine in a gas turbine engine is disclosed. The active bypass flow control system is an adjustable system in which one or more metering devices may be used to control the flow of bypass compressed air as the flow of compressed air past the outer balance seal changes over time as the outer balance seal between the rim cavity and the cooling cavity wears In at least one embodiment, the metering device may include an annular ring having at least one metering orifice extending therethrough, whereby alignment of the metering orifice with the outlet may be adjustable to change a cross-sectional area of an opening of aligned portions of the outlet and the metering orifice.

The IRES electronic seal

International Nuclear Information System (INIS)

Autrusson, B.; Brochard, D.; Moreau, J.F.; Martin, J.C.

2001-01-01

In the framework of the French Support Program for the IAEA Safeguards, the 'Institut de Protection et de Surete Nucleaire' (IPSN), developed an electronic seal called Integrated and Reusable Electronic Seal (IRES) that enables independent verification by different inspectorates (IAEA, Euratom, and National Inspectorate). The seal can be remotely interrogated by radio frequency and integrated to other Containment/surveillance systems by serial line RS 485. Data are authenticated and the IRESMAG software manages in the seal reader all functionalities of the seal and records inspection data compatible with the IAEA's Seal Database. To perform this development, IPSN relies on industrial partners: SAPHYMO for the general architecture of the seal and the electronics, THALES for the authentication of data and the security of transmission. The main features of the IRES seal are the following: Interrogation by different inspectorate, allowing independent conclusions; Recording of events, including tampering, in a non-volatile memory; Authentication of data and enhanced security of the communication between the seal and the seal reader; Remote interrogation by an inspector or/and automatic for unattended systems or remote monitoring; Reusable after erasing the seal memory and replacement of the batteries

Development of Mechanical Sealing and Laser Welding Technology to Instrument Thermocouple for Nuclear Fuel Test Rod

Energy Technology Data Exchange (ETDEWEB)

Joung, Chang-Young; Ahn, Sung-Ho; Hong, Jin-Tae; Kim, Ka-Hye; Huh, Sung-Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-05-15

Zircaloy-4 of the nuclear fuel test rod, AISI 316L of the mechanical sealing parts, and the MI (mineral insulated) cable at a thermocouple instrumentation are hetero-metals, and are difficult to weld to dissimilar materials. Therefore, a mechanical sealing method to instrument the thermocouple should be conducted using two kinds of sealing process as follows: One is a mechanical sealing process using Swagelok, which is composed of sealing components that consists of an end-cap, a seal tube, a compression ring and a Swagelok nut. The other is a laser welding process used to join a seal tube, and an MI cable, which are made of the same material. The mechanical sealing process should be sealed up with the mechanical contact compressed by the strength forced between a seal tube and an end-cap, and the laser welding process should be conducted to have no defects on the sealing area between a seal tube and an MI cable. Therefore, the mechanical sealing and laser welding techniques need to be developed to accurately measure the centerline temperature of the nuclear fuel test rod in an experimental reactor. The mechanical sealing and laser welding tests were conducted to develop the thermocouple instrumentation techniques for the nuclear fuel test rod. The optimum torque value of a Swagelok nut to seal the mechanical sealing part between the end-cap and seal tube was established through various torque tests using a torque wrench. The optimum laser welding conditions to seal the welding part between a seal tube and an MI cable were obtained through various welding tests using a laser welding system.

Development of Mechanical Sealing and Laser Welding Technology to Instrument Thermocouple for Nuclear Fuel Test Rod

International Nuclear Information System (INIS)

Joung, Chang-Young; Ahn, Sung-Ho; Hong, Jin-Tae; Kim, Ka-Hye; Huh, Sung-Ho

2015-01-01

Zircaloy-4 of the nuclear fuel test rod, AISI 316L of the mechanical sealing parts, and the MI (mineral insulated) cable at a thermocouple instrumentation are hetero-metals, and are difficult to weld to dissimilar materials. Therefore, a mechanical sealing method to instrument the thermocouple should be conducted using two kinds of sealing process as follows: One is a mechanical sealing process using Swagelok, which is composed of sealing components that consists of an end-cap, a seal tube, a compression ring and a Swagelok nut. The other is a laser welding process used to join a seal tube, and an MI cable, which are made of the same material. The mechanical sealing process should be sealed up with the mechanical contact compressed by the strength forced between a seal tube and an end-cap, and the laser welding process should be conducted to have no defects on the sealing area between a seal tube and an MI cable. Therefore, the mechanical sealing and laser welding techniques need to be developed to accurately measure the centerline temperature of the nuclear fuel test rod in an experimental reactor. The mechanical sealing and laser welding tests were conducted to develop the thermocouple instrumentation techniques for the nuclear fuel test rod. The optimum torque value of a Swagelok nut to seal the mechanical sealing part between the end-cap and seal tube was established through various torque tests using a torque wrench. The optimum laser welding conditions to seal the welding part between a seal tube and an MI cable were obtained through various welding tests using a laser welding system

Reactor vessel sealing plug

International Nuclear Information System (INIS)

Dooley, R.A.

1986-01-01

This invention relates to an apparatus and method for sealing the cold leg nozzles of a nuclear reactor pressure vessel from a remote location during maintenance and inspection of associated steam generators and pumps while the pressure vessel and refueling canal are filled with water. The apparatus includes a sealing plug for mechanically sealing the cold leg nozzle from the inside of a reactor pressure vessel. The sealing plugs include a primary and a secondary O-ring. An installation tool is suspended within the reactor vessel and carries the sealing plug. The tool telescopes to insert the sealing plug within the cold leg nozzle, and to subsequently remove the plug. Hydraulic means are used to activate the sealing plug, and support means serve to suspend the installation tool within the reactor vessel during installation and removal of the sealing plug

Development of a resilient mechanical sealing solution to resist electro corrosion in ultrapure feedwater applications

Energy Technology Data Exchange (ETDEWEB)

Loenhout, Gerard van [Flowservice Flow Solutions Division, Etten-Leur (Netherlands); Enders, Klaus; Schmerberg, Rainer [Vattenfall Europe Generation AG, Peitz (Germany)

2012-11-01

Ever since the introduction of mechanical seals on high speed boiler feed pumps in the sixties, mechanical seals have proven to be a reliable, cost effective sealing method. However, since the introduction of combined water treatment chemistry used in today's modern fossil-fuelled power stations, keeping mechanical seal reliability high, became a challenge. A pragmatic approach is presented. A resilient sealing solution was developed to resist electro corrosion for such critical feed water pumps. (orig.)

Development and fabrication of insulator seals for thermionic diodes

Science.gov (United States)

Poirier, V. L.

1972-01-01

Eight different types of cermet seals for thermionic diodes were investigated: (1) 1 micron Al2O3 with Nb spheres; (2) 200 A Al2O3 with Nb spheres; (3) 1 micron Al2O3 with Nb 1% Zr spheres; (4) 200 A Al2O3 with Nb 1% Zr spheres; (5) Pure Y2O3 with Nb 1% Zr spheres; (6) Y2O3 3% ZrO2 with Nb 1% Zr spheres; (7) Y2O3 10% ZrO2 with Nb 1% Zr spheres; and (8) ZrO2 12% Y2O3 with Nb 1% Zr spheres. Investigations were made to determine the most favorable fabrication techniques and the effect of the bonding cycle, (length of bonding time and shutdown sequences). The analysis of the seals included tensile test, vacuum test, electrical test and metallurgical examination. At the conclusion of the development phase, 36 seals were fabricated for delivery for evaluation.

Management of spent sealed sources in Indonesia

International Nuclear Information System (INIS)

Wisnubroto, D.S.

2002-01-01

This paper describes the effort of the Center for Development of Radioactive Waste Management (CDRWM) to develop and implement activities in maintaining and improving the safety of spent sealed radiation sources and the security of radioactive materials over their life cycle. There is a wide variety of uses of radiation sources and radioactive materials in Indonesia, while the CDRWM plan to cover all spent radiation sources. Primary consideration is given to sealed radiation sources with relatively high levels of radioactivity which might necessitate interventional measures should control over them be lost. The policy of the Government of Indonesia for spent radiation sources is, whenever possible, spent sealed sources should be returned to the supplier. CDRWM has a general principle that sealed sources should not be removed from their holders, or the holders physically modified (except for Ra-226 needles, smoke detector and lighting preventer). (author)

Study and Development of Face-Contact, Bellows Mechanical Seal for Liquid Hydrogen Turbopump

OpenAIRE

NOSAKA, Masataka; SUZUKI, Mineo; MIYAKAWA, Yukio; KAMIJO, Kenjiro; KIKUCHI, Masataka; MORI, Masahiro; 野坂, 正隆; 鈴木, 峰男; 宮川, 行雄; 上絛, 謙二郎; 菊池, 正孝; 森, 雅裕

1981-01-01

The development of a 10-ton thrust liquid oxygen and liquid hydrogen (LOX and LH2) rocket engine is under way at the National Space Development Agency. In advance of the development of a liquid hydrogen turbopump, the National Aerospace Laboratory carried out study and development of a face-contact, bellows mechanical seal for a liquid hydrogen turbopump in co-operation with the National Space Development Agency. The present report describes the fundamental experiments of the mechanical seal ...

Development of a Sealing-Bolt for the safeguarding of large containers such as multielement bottles

International Nuclear Information System (INIS)

D'Agraives, B.C.; Toornvliet

1985-01-01

A preliminary study on the development of a ''Sealing-Bolt'' is currently being carried out at JRC-Ispra. It is required for the safeguarding of large containers. A ''Sealing-Bolt'' would replace one - or more - of the conventional bolts, normally used for tightening a container's cover. It could not be removed - or unscrewed - without the knowledge of Inspectors. Thus, it has to meet the requirements of an Underwater Verifiable Seal and of a Threaded Stud-Bolt. It is proposed to derive the sealing feature from the VAK III seal, a LWR Fuel Assembly Ultrasonic Seal which has been developed by JRC-Ispra and is field tested at the Kahl Reactor Facility (FRG) since October 1983, while under evaluation for use by IAEA. The mechanical part asks for a specific study of a reliable system able to evidence that the bolt has been unscrewed during an opening of the lid

Reactor coolant pump seal leakage monitoring

International Nuclear Information System (INIS)

Stevens, D.M.; Spencer, J.W.; Morris, D.J.; James, W.; Shugars, H.G.

1986-01-01

Problems with reactor coolant pump seals have historically accounted for a large percentage of unscheduled outages. Studies performed for the Electric Power Research Institute (EPRI) have shown that the replacement of coolant pump seals has been one of the leading causes of nuclear plant unavailability over the last ten years. Failures of coolant pump seals can lead to primary coolant leakage rates of 200-500 gallons per minute into the reactor building. Airborne activity and high surface contamination levels following these failures require a major cleanup effort and increases the time and personnel exposure required to refurbish the pump seals. One of the problems in assessing seal integrity is the inability to accurately measure seal leakage. Because seal leakage flow is normally very small, it cannot be sensed directly with normal flow instrumentation, but must be inferred from several other temperature and flow measurements. In operating plants the leakage rate has been quantified with a tipping-bucket gauge, a device which indicates when one quart of water has been accumulated. The tipping-bucket gauge has been used for most rainfall-intensity monitoring. The need for a more accurate and less expensive gauge has been addressed. They have developed a drop-counter precipitation sensor has been developed and optimized. The applicability of the drop-counter device to the problem of measuring seal leakage is being investigated. If a review of system specification and known drop-counter performance indicates that this method is feasible for measuring seal leak rates, a drop-counter gauge will be fabricated and tested in the laboratory. If laboratory tests are successful the gauge will be demonstrated in a pump test loop at Ontario Hydro and evaluated under simulated plant conditions. 3 references, 2 figures

Nuclear waste vault sealing

International Nuclear Information System (INIS)

Gyenge, M.

1980-01-01

A nuclear waste vault must be designed and built to ensure adequate isolation of the nuclear wastes from human contact. Consequently, after a vault has been fully loaded, it must be adequately sealed off to prevent radionuclide migration which may be provided by circulating groundwater. Vault sealing entails four major aspects, i.e.: (a) vault grouting; (b) borehole sealing; (c) buffer packing; and (d) backfilling. Of particular concern in vault sealing are the physical and chemical properties of the sealing material, its long-term durability and stability, and the techniques used for its emplacement. Present sealing technology and sealing materials are reviewed in terms of the particular needs of vault sealing. Areas requiring research and development are indicated

Upgrading inflatable door seals

International Nuclear Information System (INIS)

Sykes, T.M.; Metcalfe, R.; Welch, L.A.; Josefowich, J.M.

1997-01-01

Inflatable door seals are used for airlocks in CANDU stations. They have been a significant source of unreliability and maintenance cost. A program is underway to improve their performance and reliability, backed by environmental qualification testing. Only commercial products and suppliers existed in 1993. For historical reasons, these 'existing products' did not use the most durable material then available. In hindsight, neither had they been adapted nor optimized to combat conditions often experienced in the plants-sagging doors, damaged sealing surfaces, and many thousands of openings and closings per year. Initial attempts to involve the two existing suppliers in efforts to upgrade these seals were unsuccessful. Another suitable supplier had therefore to be found, and a 'new,' COG-owned seal developed; this was completed in 1997. This paper summarizes its testing, along with that of the two existing products. Resistance to aging has been improved significantly. Testing has shown that an accident can be safely withstood after 10 years of service or 40,000 openings-closings, whichever comes first. AECL's Fluid Sealing Technology Unit (FSTU) has invested in the special moulds, test fixtures and other necessary tooling and documentation required to begin commercial manufacture of this new quality product. Accordingly, as with FSTU's other nuclear products such as pump seals, the long-term supply of door seals to CANDU plants is now protected from many external uncertainties-e.g., commercial products being discontinued, materials being changed, companies going out of business. Manufacturing to AECL's detailed specifications is being subcontracted to the new supplier. FSTU is performing the quality surveillance, inspection, testing, and customer service activities concomitant with direct responsibility for supply to the plants. (author)

Development of a CFD Code for Analysis of Fluid Dynamic Forces in Seals

Science.gov (United States)

Athavale, Mahesh M.; Przekwas, Andrzej J.; Singhal, Ashok K.

1991-01-01

The aim is to develop a 3-D computational fluid dynamics (CFD) code for the analysis of fluid flow in cylindrical seals and evaluation of the dynamic forces on the seals. This code is expected to serve as a scientific tool for detailed flow analysis as well as a check for the accuracy of the 2D industrial codes. The features necessary in the CFD code are outlined. The initial focus was to develop or modify and implement new techniques and physical models. These include collocated grid formulation, rotating coordinate frames and moving grid formulation. Other advanced numerical techniques include higher order spatial and temporal differencing and an efficient linear equation solver. These techniques were implemented in a 2D flow solver for initial testing. Several benchmark test cases were computed using the 2D code, and the results of these were compared to analytical solutions or experimental data to check the accuracy. Tests presented here include planar wedge flow, flow due to an enclosed rotor, and flow in a 2D seal with a whirling rotor. Comparisons between numerical and experimental results for an annular seal and a 7-cavity labyrinth seal are also included.

Continuous improvement of pump seals

International Nuclear Information System (INIS)

Wong, W.; Eyvindson, A.; Rhodes, D.B.

2003-01-01

Pump seal reliability continues to be an area needing improvement and ongoing vigilance. Methods have been developed for identifying and assessing factors relating to seal performance, selecting the most relevant ones for a specific station, and then focusing on the most significant aspects and how to improve. Discussion invariably addresses maintenance practices, seal design, monitoring capabilities, operating conditions, transients, and pump and motor design. Success in reliability improvement requires ongoing dialogue among the station operators, pump manufacturers and seal designers. AECL CAN-seals lead the nuclear industry in reliability and seal life. They effectively save operators millions of dollars in outage time and person-rem. This paper describes some of the significant developments in AECL's ongoing program in seal R and D, as well as recent new installations following the most demanding seal qualification programs to date. (author)

Development of prismatic sealed nickel-cadmium battery, 2000PF

Energy Technology Data Exchange (ETDEWEB)

Arahi,; Kazuo,; Yoshimura, Hideaki; Takeshima, Kenji; Kawamura, Chiaki

1988-10-21

Though, as for the sealed Ni-Cd battery, that of cylindrical form has been majorly used, that of prismatic form is heightened in needs, with the portable electronic appliances made smaller and thinner, for which needs a new type battery 2000 PF, by new production process technology and components, was developed. As compared with the past cylindrical sealed Ni-Ca batter, generally less than 100Wh/l in energy density, the new one is higher and 133Wh/l in it, with the achievement of a 17 to 34% lightening in weight. That heightening in energy density was realized by the optimized design of lamination structure, availing of the advantage not to necessitate the electrode to be wound in a spiral form, as necessary in the cylindrical battery. While as the sealing by caulking can not be adopted like the cylindrical battery, a precise welding technique by laser was established. The assembly line is of an almost unmanned on-line computer control system. The charge and discharge characteristics, etc. were indicated in detail. 11 figures, 1 table.

Crashworthy sealed pressure vessel for plutonium transport

International Nuclear Information System (INIS)

Andersen, J.A.

1980-01-01

A rugged transportation package for the air shipment of radioisotopic materials was recently developed. This package includes a tough, sealed, stainless steel inner containment vessel of 1460 cc capacity. This vessel, intended for a mass load of up to 2 Kg PuO 2 in various isotopic forms (not to exceed 25 watts thermal activity), has a positive closure design consisting of a recessed, shouldered lid fastened to the vessel body by twelve stainless-steel bolts; sealing is accomplished by a ductile copper gasket in conjunction with knife-edge sealing beads on both the body and lid. Follow-on applications of this seal in newer, smaller packages for international air shipments of plutonium safeguards samples, and in newer, more optimized packages for greater payload and improved efficiency and utility, are briefly presented

SEALING SIMULATED LEAKS

Energy Technology Data Exchange (ETDEWEB)

Michael A. Romano

2004-09-01

This report details the testing equipment, procedures and results performed under Task 7.2 Sealing Simulated Leaks. In terms of our ability to seal leaks identified in the technical topical report, Analysis of Current Field Data, we were 100% successful. In regards to maintaining seal integrity after pigging operations we achieved varying degrees of success. Internal Corrosion defects proved to be the most resistant to the effects of pigging while External Corrosion proved to be the least resistant. Overall, with limitations, pressure activated sealant technology would be a viable option under the right circumstances.

Time budgets and activity patterns of sub-Antarctic fur seals at ...

African Journals Online (AJOL)

1993-04-15

Apr 15, 1993 ... tially influence the activity patterns of fur seals when they are ashore, and their relatively ... modified by cloud cover and shade (which advanced pro- gressively across the ..... Influence of climate on the distri- bution of walruses ...

Advanced High Temperature Structural Seals

Science.gov (United States)

Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Rorabaugh, Michael; Shorey, Mark

2002-10-01

This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.

Management of Disused Radioactive Sealed Sources in Egypt - 13512

International Nuclear Information System (INIS)

Mohamed, Y.T.; Hasan, M.A.; Lasheen, Y.F.

2013-01-01

The future safe development of nuclear energy and progressive increasing use of sealed sources in medicine, research, industry and other fields in Egypt depends on the safe and secure management of disused radioactive sealed sources. In the past years have determined the necessity to formulate and apply the integrated management program for radioactive sealed sources to assure harmless and ecological rational management of disused sealed sources in Egypt. The waste management system in Egypt comprises operational and regulatory capabilities. Both of these activities are performed under legislations. The Hot Laboratories and Waste Management Center HLWMC, is considered as a centralized radioactive waste management facility in Egypt by law 7/2010. (authors)

A hybrid floating brush seal (HFBS) for improved sealing and wear performance in turbomachinery applications

Science.gov (United States)

Lattime, Scott Byran

A conceptually new type of seal has been developed for gas turbine applications which dramatically reduces wear and leakage associated with current labyrinth and brush seal technologies. The Hybrid Floating Brush Seal (HFBS) combines brush seal and film riding face seal technologies to create a hybrid seal that allows both axial and radial excursions of the sealed shaft, while simultaneously eliminating interface surface speeds (friction and heat) between the rotor and the brush material that characterize standard brush seal technology. A simple test rig was designed to evaluate feasibility of the HFBS under relatively low pressures and rotational speeds (50psig, 5krpm). A second test stand was created to study the effects of centrifugal force on bristle deflection. A third test facility was constructed for prototype development and extensive room temperature testing at moderate pressures and fairly high rotational speeds (100psig, 40krpm). This test rig also allowed the evaluation of the HFBS during axial movement of a rotating shaft. An analytical model to predict the effects of centrifugal force on the bristles of a rotating brush seal was developed. Room temperature analysis of the HFBS proved successful for relatively high operating rotational velocities at moderate pressures with very acceptable leakage rates for gas turbine engines. Brush seals were able to track rotor speeds up to 24krpm while maintaining sealing integrity. The HFBS's ability to function under axial shaft displacement and synchronous dynamic radial loading was also proven successful. Hydrodynamic performance of the face seal was proven to provide adequate stiffness and load carrying capacity to keep the brush seal from contacting the face seal at pressure drops across the brush of up to 100psi. Leakage performance over standard brush seal and labyrinth technology was quite dramatic. The HFBS showed its sealing advantage using much higher radial interference between the rotor and the bristle

Cover gas seals. 11 - FFTF-LMFBR seal-test program, January-March 1974

International Nuclear Information System (INIS)

Kurzeka, W.; Oliva, R.; Welch, F.

1974-01-01

The objectives of this program are to: (1) conduct static and dynamic tests to demonstrate or determine the mechanical performance of full-size (cross section) FFTF fuel transfer machine and reactor vessel head seals intended for use in a sodium vapor - inert gas environment, (2) demonstrate that these FFTF seals or new seal configuration provide acceptable fission product and cover gas retention capabilities at LMFBR Clinch River Plant operating environmental conditions other than radiation, and (3) develop improved seals and seal technology for the LMFBR Clinch River Plant to support the national objective to reduce all atmospheric contaminations to low levels

The IRES electronic seal

International Nuclear Information System (INIS)

Gourlez, P.; Funk, P.; Brochard, D.; Moreau, J.F.; Martin, J.C.

2001-01-01

In the framework of the French Support Program for the IAEA Safeguards, the 'Institut de Protection et de Surete Nucleaire' (IPSN), developed an electronic seal called Integrated and Reusable Electronic Seal (IRES) that enables independent verification by different inspectorates (IAEA, Euratom, and National Inspectorate) Furthermore, a bilateral co-ordination between Euratom and French domestic safeguards takes place in some French facilities regarding a common approach concerning the seals especially in case of crisis situation. The seal can be remotely interrogated by radio frequency and integrated to other Containment/surveillance systems by serial line RS 485. Data are authenticated and the IRESMAG software manages in the seal reader all functionalities of the seal and records inspection data compatible with the IAEA's Seal Database

Development of laser beam welding for the lip seal configuration

International Nuclear Information System (INIS)

Yadav, Ashish; Joshi, Jaydeep; Singh, Dhananjay Kumar; Natu, Harshad; Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun

2015-01-01

Highlights: • Laser welding parameter optimization for required weld penetration. • Parametric study of actual scenarios like air gap, plate & beam misalignment. • Destructive and non-destructive examination of the welds and He-leak testing. - Abstract: A vacuum seal using the lip sealing technique is emerging as the most likely choice for fusion devices, to comply with the requirement of maintainability. The welding technology considered for lip sealing is laser welding, due to the attributes of small spot diameter, low concentrated heat input, high precision and penetration. To establish the process, an experiment has been conducted on a sample size of 150 mm × 50 mm having thickness of 2 mm, material AISI304L to assess the dependence of beam parameters like, laser power, speed and focusing distance on penetration and quality of weld joint. Further, the assessment of the effect of welding set-up variables like air-gap between plates, plate misalignment, and laser beam misalignment on the weld quality is also required. This paper presents the results of this experimental study and also the plan for developing a large (∼10 m) size laser welded seal, that simulates, appropriately, the configuration required in large dimension fusion devices.

Development of laser beam welding for the lip seal configuration

Energy Technology Data Exchange (ETDEWEB)

Yadav, Ashish, E-mail: ashish.yadav@iter-india.org [ITER-India, Institute for Plasma Research, Sector 25, Gandhinagar 382016, Gujarat (India); Joshi, Jaydeep; Singh, Dhananjay Kumar [ITER-India, Institute for Plasma Research, Sector 25, Gandhinagar 382016, Gujarat (India); Natu, Harshad [Magod Laser Machining Pvt. Ltd., KIADB Ind. Area, Jigani, Anekal Taluk, Bengaluru 560105 (India); Rotti, Chandramouli; Bandyopadhyay, Mainak; Chakraborty, Arun [ITER-India, Institute for Plasma Research, Sector 25, Gandhinagar 382016, Gujarat (India)

2015-10-15

Highlights: • Laser welding parameter optimization for required weld penetration. • Parametric study of actual scenarios like air gap, plate & beam misalignment. • Destructive and non-destructive examination of the welds and He-leak testing. - Abstract: A vacuum seal using the lip sealing technique is emerging as the most likely choice for fusion devices, to comply with the requirement of maintainability. The welding technology considered for lip sealing is laser welding, due to the attributes of small spot diameter, low concentrated heat input, high precision and penetration. To establish the process, an experiment has been conducted on a sample size of 150 mm × 50 mm having thickness of 2 mm, material AISI304L to assess the dependence of beam parameters like, laser power, speed and focusing distance on penetration and quality of weld joint. Further, the assessment of the effect of welding set-up variables like air-gap between plates, plate misalignment, and laser beam misalignment on the weld quality is also required. This paper presents the results of this experimental study and also the plan for developing a large (∼10 m) size laser welded seal, that simulates, appropriately, the configuration required in large dimension fusion devices.

Development of sealed radioactive sources immobilized in epoxy resin for verification of detectors used in nuclear medicine

Energy Technology Data Exchange (ETDEWEB)

Tiezzi, Rodrigo; Rostelato, Maria Elisa C.M.; Nagatomi, Helio R.; Zeituni, Calos A.; Benega, Marcos A.G.; Souza, Daiane B. de; Costa, Osvaldo L. da; Souza, Carla D.; Rodrigues, Bruna T.; Souza, Anderson S. de; Peleias Junior, Fernando S.; Santos, Rafael Melo dos; Melo, Emerson Ronaldo de, E-mail: rktiezzi@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Karan Junior, Dib [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil)

2015-07-01

The radioactive sealed sources are used in verification ionization chamber detectors, which measure the activity of radioisotopes used in several areas, such as in nuclear medicine. The measurement of the activity of radioisotopes must be made with accuracy, because it is administered to a patient. To ensure the proper functioning of the ionization chamber detectors, standardized tests are set by the International Atomic Energy Agency (IAEA) and the National Nuclear Energy Commission using sealed radioactive sources of Barium-133, Cesium-137 and Cobalt-57. The tests assess the accuracy, precision, reproducibility and linearity of response of the equipment. The focus of this work was the study and the development of these radioactive sources with standard Barium-133, Cesium-137 and Cobalt-57,using a polymer, in case commercial epoxy resin of diglycidyl ether of bisphenol A (DGEBA) and a curing agent based on modified polyamine diethylenetriamine (DETA), to immobilize the radioactive material. The polymeric matrix has the main function of fix and immobilize the radioactive contents not allowing them to leak within the technical limits required by the standards of radiological protection in the category of characteristics of a sealed source and additionally have the ability to retain the emanation of any gases that may be formed during the manufacture process and the useful life of this artifact. The manufacturing process of a sealed source standard consists of the potting ,into bottle standardized geometry, in fixed volume of a quantity of a polymeric matrix within which is added and dispersed homogeneously to need and exact amount in activity of the radioactive materials standards. Accordingly, a study was conducted for the choice of epoxy resin, analyzing its characteristics and properties. Studies and tests were performed, examining the maximum solubility of the resin in water (acidic solution, simulating the conditions of radioactive solution), loss of mechanical

Sealing of investigation boreholes, Phase 4 - Final report

Energy Technology Data Exchange (ETDEWEB)

Pusch, Roland [Drawrite AB, Luleaa Technical University, Luleaa (Sweden); Ramqvist, Gunnar [El-Tekno AB, Figeholm (Sweden); Bockgaard, Niclas [Golder Associates, Goeteborg (Sweden); Ekman, Lennart [LE Geokonsult AB, Baelinge (Sweden)

2011-09-15

The report describes the outcome of Phase 4 of the project 'Sealing of investigation boreholes', which deals with 1) characterization and planning of borehole sealing, 2) performance and quality assessment, 3) sealing of large diameter holes, and 4) interaction of clay and concrete plugs. A specific goal was to find ways to characterize, plan and seal of boreholes so that their impact on the overall hydraulic performance of the repository rock can predicted and controlled. The work comprised selection of representative 'reference holes' at the Laxemar and Forsmark sites for development of a general programme for planning and simulating implementation of borehole plugging campaigns, considering also cost issues. A second aim was to define and quantify the role of seals in the reference holes for finding out how important sealing really is. A third was to test a practical way to seal large diameter boreholes and a fourth to find out how concrete matures and performs in contact with smectite clay. The study demonstrated, in conclusion, the need for developing techniques for preparing deep boreholes before lasting seals are installed in them, since poor sealing can short-circuit hydraulically important fracture zones intersected by the holes. The practically oriented sealing activities showed that the technique developed for tight sealing of large-diameter boreholes is practical and feasible. The issue of chemical stability was investigated by testing the performance and constitution of a plug consisting of CBI concrete in contact with smectite-rich seals for almost three years. This study showed that none of them underwent substantial degradation in this period of time, but chemical reactions and thereby generated changes in physical behaviour of the plug components had taken place, particularly in the clay. The rate of degradation is, however, not yet known. It was concluded from this study that it is suitable to carry out a corresponding

Sealing of investigation boreholes, Phase 4 - Final report

International Nuclear Information System (INIS)

Pusch, Roland; Ramqvist, Gunnar; Bockgaard, Niclas; Ekman, Lennart

2011-09-01

The report describes the outcome of Phase 4 of the project 'Sealing of investigation boreholes', which deals with 1) characterization and planning of borehole sealing, 2) performance and quality assessment, 3) sealing of large diameter holes, and 4) interaction of clay and concrete plugs. A specific goal was to find ways to characterize, plan and seal of boreholes so that their impact on the overall hydraulic performance of the repository rock can predicted and controlled. The work comprised selection of representative 'reference holes' at the Laxemar and Forsmark sites for development of a general programme for planning and simulating implementation of borehole plugging campaigns, considering also cost issues. A second aim was to define and quantify the role of seals in the reference holes for finding out how important sealing really is. A third was to test a practical way to seal large diameter boreholes and a fourth to find out how concrete matures and performs in contact with smectite clay. The study demonstrated, in conclusion, the need for developing techniques for preparing deep boreholes before lasting seals are installed in them, since poor sealing can short-circuit hydraulically important fracture zones intersected by the holes. The practically oriented sealing activities showed that the technique developed for tight sealing of large-diameter boreholes is practical and feasible. The issue of chemical stability was investigated by testing the performance and constitution of a plug consisting of CBI concrete in contact with smectite-rich seals for almost three years. This study showed that none of them underwent substantial degradation in this period of time, but chemical reactions and thereby generated changes in physical behaviour of the plug components had taken place, particularly in the clay. The rate of degradation is, however, not yet known. It was concluded from this study that it is suitable to carry out a corresponding investigation of the plugs

Research on seal control systems for international nuclear safeguard and the vulnerability assessment on the seals

International Nuclear Information System (INIS)

Zhang Hongjian; Liu Tianshu; Cao Fangfang; Xu Chunyan

2014-01-01

Safeguard seals, also called Tamper-indicating devices (TIDs), are widely used to detect tampering or unauthorized entry in the international safeguard and security systems, Seal control systems consist of seal implementing plan, seal development and the vulnerability assessment on tbe seals, effective implementing procedures and methods of the seals. The vulnerability assessment contents of safeguard seals, thermo-shrinked film seals being as an example, and seals control systems in the implementation program are researched. The seal control systems discuss task assignment, seals management flow and seals program data flow to promote applying effectively seals. The vulnerability assessment program of seals studies assurance level to some different tampering techniques and measures. The researches must promote utilizing seals effectively for nuclear security, non-proliferation of nuclear weapons, radioactive waste management, and the nuclear material accounting and control. (authors)

Hydrodynamic perception in true seals (Phocidae) and eared seals (Otariidae).

Science.gov (United States)

Hanke, Wolf; Wieskotten, Sven; Marshall, Christopher; Dehnhardt, Guido

2013-06-01

Pinnipeds, that is true seals (Phocidae), eared seals (Otariidae), and walruses (Odobenidae), possess highly developed vibrissal systems for mechanoreception. They can use their vibrissae to detect and discriminate objects by direct touch. At least in Phocidae and Otariidae, the vibrissae can also be used to detect and analyse water movements. Here, we review what is known about this ability, known as hydrodynamic perception, in pinnipeds. Hydrodynamic perception in pinnipeds developed convergently to the hydrodynamic perception with the lateral line system in fish and the sensory hairs in crustaceans. So far two species of pinnipeds, the harbour seal (Phoca vitulina) representing the Phocidae and the California sea lion (Zalophus californianus) representing the Otariidae, have been studied for their ability to detect local water movements (dipole stimuli) and to follow hydrodynamic trails, that is the water movements left behind by objects that have passed by at an earlier point in time. Both species are highly sensitive to dipole stimuli and can follow hydrodynamic trails accurately. In the individuals tested, California sea lions were clearly more sensitive to dipole stimuli than harbour seals, and harbour seals showed a superior trail following ability as compared to California sea lions. Harbour seals have also been shown to derive additional information from hydrodynamic trails, such as motion direction, size and shape of the object that caused the trail (California sea lions have not yet been tested). The peculiar undulated shape of the harbour seals' vibrissae appears to play a crucial role in trail following, as it suppresses self-generated noise while the animal is swimming.

Effect of bar sealing parameters on OPP/MCPP heat seal strength

Directory of Open Access Journals (Sweden)

2007-11-01

Full Text Available The effect of bar sealing parameters on the heat seal strength of oriented polypropylene (OPP/metallic cast polypropylene (MCPP laminate film was investigated. Based on the results obtained from the parametric study, a bar sealing process window was developed. All points drop within the process window are combinations of platen temperature and dwell time that produce acceptable heat seal. Optimum combinations are indicated by the lower border of the window. The plateau initiation temperature, Tpi of OPP/MCPP laminate film used in the present study occurred before the final melting temperature, Tmf of the sealant material. The highest achievable heat seal strength was at the plateau region, and the corresponding failure modes were delaminating, tearing or combine failure modes (delaminating and tearing. Minimum pressure level of 1.25 bars is necessary to bring the laminate interface into intimate contact in order to effect sealing.

Electrochemical investigations of activation and degradation of hydrogen storage alloy electrodes in sealed Ni/MH battery

Energy Technology Data Exchange (ETDEWEB)

Chen, W.X.; Xu, Z.D. [Zhejiang University, Hangzhou (China). Dept. of Chemistry; Tu, J.P. [Zhejiang University, Hangzhou (China). Dept. of Materials Science and Engineering

2002-04-01

The M1Ni{sub 0.4}Co{sub 0.6}Al{sub 0.4} alloy was treated with hot alkaline solution containing a small amount of KBH{sub 4} and its effect on the activation and degradation behaviors of the hydrogen storage alloy electrodes in sealed Ni/MH batteries was investigated. It was found that the treated alloy electrode exhibited a better activation property than the untreated one in the sealed battery as well as in open cell. For the treated alloy electrode activating, the polarization resistance in the sealed battery was almost equal to that in the open cell. But in the case of the untreated alloy electrode activating, the polarization resistance in the sealed battery was larger than that in the open cell. The reason is that the oxide film on the untreated alloy surface suppressed the combination of the oxygen evolved on the positive electrode with hydrogen on the negative alloy surface. In addition, the decaying of capacity of the untreated alloy electrode was much faster than that of the treated one. The reasons were, that after surface treatment, the Ni-rich and Al-poor layer on the alloy surface not only had a high electrocatalytic activity for hydrogen electrode reaction, but also facilitated the combination of the oxygen with hydrogen and hydrogen adsorption on the alloy surface. (author)

A magnetic fluid seal for rotary blood pumps: effects of seal structure on long-term performance in liquid.

Science.gov (United States)

Mitamura, Yoshinori; Takahashi, Sayaka; Amari, Shuichi; Okamoto, Eiji; Murabayashi, Shun; Nishimura, Ikuya

2011-03-01

A magnetic fluid (MF) seal enables mechanical contact-free rotation of the shaft and hence has excellent durability. The performance of an MF seal, however, has been reported to decrease in liquids. We developed an MF seal that has a "shield" mechanism, and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. Three types of MF seals were used. Seal A was a conventional seal without a shield. Seal B had the same structure as that of Seal A, but the seal was installed at 1 mm below liquid level. Seal C was a seal with a shield and the MF was set at 1 mm below liquid level. Seal A failed after 6 and 11 days. Seal B showed better results (20 and 73 days). Seal C showed long-term durability (217 and 275 days). The reason for different results in different seal structures was considered to be different flow conditions near the magnetic fluid. Fluid dynamics near the MF in the pump were analyzed using computational fluid dynamics (CFD) software. We have developed an MF seal with a shield that works in liquid for >275 days. The MF seal is promising as a shaft seal for rotary blood pumps.

Sealing properties of mechanical seals for an axial flow blood pump.

Science.gov (United States)

Tomioka, J; Mori, T; Yamazaki, K; Koyanagi, H

1999-08-01

A miniature intraventricular axial flow blood pump for left ventricular support is under development. One of the key technologies required for such pumps is sealing of the motor shaft. In this study, to prevent blood backflow into the motor side, mechanical seals were developed and their sealing properties investigated. In the experimental apparatus, the mechanical seal separated the bovine blood on the chamber side from the cooling water on the motor side. A leakage of the blood was measured by inductively coupled plasma (ICP) light emission analysis. The rate of hemolysis was measured by the cyanmethemoglobin method. Frictional torque acting on the shaft was measured by a torque transducer. In the experiments, the rotational speed of the shaft was changed from 1,000 to 10,000 rpm, and the contact force of the seal faces was changed from 1.96 to 4.31 N. To estimate lubrication regimes, the Stribeck curve, a diagram of the coefficient of friction against the bearing characteristic G number, was drawn. The results of the experiments showed that both the leakage of blood and the rate of hemolysis were very small. The friction loss was also very small. The mechanical seal was operated in various lubrication regimes, from a fluid lubrication regime to a mixed lubrication regime.

SSME Seal Test Program: Test results for sawtooth pattern damper seal

Science.gov (United States)

Childs, D. W.

1986-01-01

Direct and transverse force coefficients for 11, sawtooth-pattern, and damper-seal configurations were examined. The designation damper seal uses a deliberately roughened stator and smooth rotor to increase the net damping force developed by a seal. The designation sawtooth-pattern refers to a stator roughness pattern. The sawtooth pattern yields axial grooves in the stator which are interrupted by spacer elements which act as flow constrictions or dams. All seals use the same smooth rotor and have the same, constant, minimum clearance. The stators examined the consequences of changes in the following design parameters: (1) axial-groove depth; (2) number of teeth: (3) number of sawtooth sections; (4) number of spacer elements; (5) dam width; (6) axially aligned sawtooth sections versus axially-staggered sawtooth sections; and (7) groove geometry. It is found that none of the sawtooth-pattern seal performs as well as the best round-hole-pattern seal. Maximum damping configurations for the sawtooth and round-hole-pattern stators have comparable stiffness performance. Several of the sawtooth pattern stators outperformed the best round-hole pattern seal.

Tamper-indicating quantum optical seals

Energy Technology Data Exchange (ETDEWEB)

Humble, Travis S [ORNL; Williams, Brian P [ORNL

2015-01-01

Confidence in the means for identifying when tampering occurs is critical for containment and surveillance technologies. Fiber-optic seals have proven especially useful for actively surveying large areas or inventories due to the extended transmission range and flexible layout of fiber. However, it is reasonable to suspect that an intruder could tamper with a fiber-optic sensor by accurately replicating the light transmitted through the fiber. In this contribution, we demonstrate a novel approach to using fiber-optic seals for safeguarding large-scale inventories with increased confidence in the state of the seal. Our approach is based on the use of quantum mechanical phenomena to offer unprecedented surety in the authentication of the seal state. In particular, we show how quantum entangled photons can be used to monitor the integrity of a fiber-optic cable - the entangled photons serve as active sensing elements whose non-local correlations indicate normal seal operation. Moreover, we prove using the quantum no-cloning theorem that attacks against the quantum seal necessarily disturb its state and that these disturbances are immediately detected. Our quantum approach to seal authentication is based on physical principles alone and does not require the use of secret or proprietary information to ensure proper operation. We demonstrate an implementation of the quantum seal using a pair of entangled photons and we summarize our experimental results including the probability of detecting intrusions and the overall stability of the system design. We conclude by discussing the use of both free-space and fiber-based quantum seals for surveying large areas and inventories.

R1800: a new Co 60 sealed source

International Nuclear Information System (INIS)

Freijo, Jose L.; Gomez, Gonzalo

2005-01-01

The increasing demand of Co 60 sealed sources in the international market has made necessary the development of new models of sealed sources. R 1800 type source up to 65 KCi has a design that allows to accommodate a wide spectrum of capsules with different specific activities. The company Dioxitek has developed the fabrication process and the design specifications needed to obtain the approval of the product. A first shipment of 100 KCi has been made with success to the United Kingdom in October of the current year. (author) [es

Seals and sealing handbook

CERN Document Server

Flitney, Robert K

2007-01-01

Wherever machinery operates there will be seals of some kind ensuring that the machine remains lubricated, the fluid being pumped does not leak, or the gas does not enter the atmosphere. Seals are ubiquitous, in industry, the home, transport and many other places. This 5th edition of a long-established title covers all types of seal by application: static, rotary, reciprocating etc. The book bears little resemblance to its predecessors, and Robert Flitney has re-planned and re-written every aspect of the subject. No engineer, designer or manufacturer of seals can afford to be without this uniq

Development of a sealed source radiation detector system for gamma ray scanning of petroleum distillation columns

International Nuclear Information System (INIS)

Vasquez Salvador, Pablo Antonio

2004-01-01

Gamma Ray Scanning is an online technique to 'view' the hydraulic performance of an operating column, with no disruption to operating processes conditions (pressure and temperature), as a cost-effective solution. The principle of this methodology consists of a small suitably sealed gamma radiation source and a radiation detector experimentally positioned to the column, moving concurrently in small increments on opposite sides and the quantity of gamma transmitted. The source-detector system consists of: a sealed ''6 0 Co radioactive source in a panoramic lead radiator, a scintillator detector coupled to a ratemeter / analyzer and a mobile system. In this work, a gamma scanning sealed source-detector system for distillation columns, was developed, comparing two scintillator detectors: NaI(Tl) (commercial) and CsI(Tl) (IPEN). In order to project the system, a simulated model of a tray-type distillation column was used. The equipment developed was tested in an industrial column for water treatment (6.5 m diameter and 40 m height). The required activities of 6 ''0Co, laboratory (11.1 MBq) and industrial works (1.48 TBq) were calculated by simulation software. Both, the NaI(Tl) and the CsI(Tl) detectors showed good proprieties for gamma scanning applications, determining the position and presence or absence of trays. (author)

Sealing device and method for sealing fractures or leaks in wall or formation surrounding tube-shaped channel

DEFF Research Database (Denmark)

2014-01-01

The sealing device (1) includes an elongated body (5) adapted to be introduced into a tube-shaped channel (2) and including a sealing fluid placement section (6) arranged between a first and a second annular flow barrier (7, 8). The elongated body further includes a sealing fluid activation secti...

An Integrated Passive (Battery-Free) Seals-and-Tag for International Safeguards

International Nuclear Information System (INIS)

Nekoogar, F.; Dowla, F.

2015-01-01

The ability to reliably and securely automate the monitoring of SNM is an important goal in Safeguards. Although item level monitoring of SNM requires both seal and tag technologies, the two technologies thus far have been developed more or less independently, and had been a lack of an integrated compact system. An integrated seal-and-tag approach not only aids inspectors to perform their tasks effectively, this approach also allows real-time inspection in large scale facilities. A typical facility could be the size of a large warehouse with hundreds or thousands of items that need to be sealed and monitored in real-time. Previously we reported on advanced secure RF passive (battery-less) tags with special features including, long-range interrogation of passive tags, communicating with passive tags with strong encryption and dynamic authentication features, and the ability to place the tags directly on metal objects. In this paper, we report on a novel secure passive tag integrated with fibre optics seal that allows real-time monitoring of items through secure wireless communications that employs AES encryption and dynamic authentication. Furthermore, the devices can be networked for large scale operations. The proposed passive seal has the same capabilities as active seals in that it allows realtime monitoring. However, the battery lifetimes of conventional active seals are limited or unpredictable. As the long-term storage of SNM might last for several years, these passive seals having been integrated with passive RF tags, extends the lifetime of the physical seals and tags indefinitely, while getting the same performance of active seals and tags. The integrated seal-and-tag is transformational in addressing a critical need in Safeguards area for long-term real-time monitoring. (author)

On-site Identification of Dynamic Annular Seal Forces in Turbo Machinery Using Active Magnetic Bearings - An Experimental Investigation

DEFF Research Database (Denmark)

Lauridsen, Jonas S.; Santos, Ilmar F.

2017-01-01

Significant dynamic forces can be generated by annular seals in rotordynamics and can under certain conditions destabilize the system leading to machine failure. Mathematical modelling of dynamic seal forces are still challenging, especially for multiphase fluids and for seals with complex...... geometries. This results in much uncertainty in the estimation of the dynamic seal forces which often leads to unexpected system behaviour. This paper presents the results of a method suitable for on-site identification of uncertain dynamic annular seal forces in rotordynamic systems supported by Active...... Magnetic Bearings (AMB). An excitation current is applied through the AMBs to obtain perturbation forces and a system response, from which, the seal coefficients are extracted by utilizing optimization and a-priori information about the mathematical model structure and its known system dynamics. As a study...

Reusable tamper-indicating security seal

International Nuclear Information System (INIS)

Ryan, M.J.

1981-01-01

A reusable tamper-indicating mechanical security seal for use in safeguarding nuclear material has been developed. The high-security seal displays an unpredictable, randomly selected, five-digit code each time it is used. This five digit code serves the same purpose that the serial number does for conventional non-reusable seals - a unique identifier for each use or application. The newly developed reusable seal is completely enclosed within a seamless, tamper-indicating, plastic jacket. The jacket is designed to reveal any attempts to penetrate, section or to chemically remove and replace with a counterfeit for surreptitious purposes

Safe management of discussed sealed sources in Peru

International Nuclear Information System (INIS)

Mallaupoma, M.

2000-01-01

The future safe development of nuclear energy and progressive increasing use of sealed sources in medicine, research, industry and other fields in Peru, in the past years have determined the necessity to formulate and apply an Institutional policy to assure harmless and ecologically rational management of disused sealed sources in Peru. Some results of the studies, which served as a basis for design and construction of a facility for treatment, conditioning and storage of conditioned sealed sources are presented in this paper. The waste management system in Peru comprises operational and regulatory capabilities. Both of these activities are performed under a legislation. The Nuclear Research Center RACSO has a radioactive waste management department which is in charge of the management of disused sealed sources produced in the country. It is considered as a centralized waste processing and storage facility (WPSF). (author)

The role of glycogen, glucose and lactate in neuronal activity during hypoxia in the hooded seal (Cystophora cristata) brain.

Science.gov (United States)

Czech-Damal, N U; Geiseler, S J; Hoff, M L M; Schliep, R; Ramirez, J-M; Folkow, L P; Burmester, T

2014-09-05

The brains of diving mammals are repeatedly exposed to hypoxic conditions during diving. Brain neurons of the hooded seal (Cystophora cristata) have been shown to be more hypoxia tolerant than those of mice, but the underlying mechanisms are not clear. Here we investigated the roles of different metabolic substrates for maintenance of neuronal activity and integrity, by comparing the in vitro spontaneous neuronal activity of brain slices from layer V of the visual cortex of hooded seals with those in mice (Mus musculus). Studies were conducted by manipulating the composition of the artificial cerebrospinal fluid (aCSF), containing either 10 mM glucose, or 20 mM lactate, or no external carbohydrate supply (aglycemia). Normoxic, hypoxic and ischemic conditions were applied. The lack of glucose or the application of lactate in the aCSF containing no glucose had little effect on the neuronal activity of seal neurons in either normoxia or hypoxia, while neurons from mice survived in hypoxia only few minutes regardless of the composition of the aCSF. We propose that seal neurons have higher intrinsic energy stores. Indeed, we found about three times higher glycogen stores in the seal brain (∼4.1 ng per μg total protein in the seal cerebrum) than in the mouse brain. Notably, in aCSF containing no glucose, seal neurons can tolerate 20 mM lactate while in mouse neuronal activity vanished after few minutes even in normoxia. This can be considered as an adaptation to long dives, during which lactate accumulates in the blood. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Radioactive sealed sources inventory and management

International Nuclear Information System (INIS)

Rodriguez C, G.; Mallaupoma G, M.; Cruz C, W.

1996-01-01

This report is related to the management of radioactive wastes, that is to say, related to the sealed sources utilized in industry, medicine and research jobs, that can not be used anymore, because of their life time termination or their activity decay to useless limits. Owing to this fact, it is necessary to take them to the Management Plant of Radioactive waste in the 'RACSO' Nuclear Center, as it is specified by the National Authority Technical Office (OTAN) regulations in Peru. The experience gained by IPEN in the sealed source management is shown in the table which informs about the radionuclide types, activity and volume amount for years. In the 'RACSO' Nuclear Center, 63 sealed sources are stored and right measures are being adopted in order to be conditioned by cementation in 200 lt steel reinforced cylinders, which are proper to their transportation and storage. A flow-chart shows the steps that the national users should follow in order to manage radioactive sealed sources and so that minimize the risks. Resulting from the agreement between the users and managers, a systematic coordination is developed, verifying the information related to the source characterization, the way of transportation and the future conditioning. It also involves the cost aspects, which in some cases, represent a big problem in the management. (authors). 3 refs., 3 figs., 1 tab

Sealed Source Security and Disposition: Progress and Prospects - 13515

International Nuclear Information System (INIS)

Jennison, Meaghan; Martin, David W.; Cuthbertson, Abigail

2013-01-01

Due to their high activity and portability, unsecured or abandoned sealed sources could cause significant health or environmental damage. Further, some of these sources could be used either individually or in aggregate in radiological dispersal devices commonly referred to as 'dirty bombs', resulting in significant social disruption and economic impacts in the billions of dollars. Disposal access for disused sealed sources, however, has been a serious challenge. From 2008 to 2012, sealed source disposal was available to only 14 states; additionally, waste acceptance criteria for sealed sources at the low-level waste disposal facilities in operation both prior to and after 2012 exclude some common yet potentially dangerous sealed sources. Recent developments, however, suggest that significant improvement in addressing this challenge is possible, although challenges remain. These developments include 1) the initiation of operations at the Waste Control Specialists (WCS) commercial low-level radioactive waste (LLRW) disposal facility in Andrews County, Texas; 2) the potential for significant revisions of the U.S. Nuclear Regulatory Commission's (NRC) 1995 'Final Branch Technical Position on Concentration Averaging and Encapsulation' (1995 BTP); and 3) the Utah Department of Environmental Quality's (UDEQ) approval of a license variance for sealed source disposal at the EnergySolutions LLRW disposal facility near Clive, Utah. (authors)

Development of circular filters for active facilities

International Nuclear Information System (INIS)

Pratt, R.P.

1986-01-01

An assessment of problems associated with remote handling, changing and disposal of filters suggested that significant improvements to filtration systems could be made if circular geometries were adopted in place of conventional systems. Improved systems have been developed and are now available for a range of applications and air flow rates. Where primary filters are installed within the active cell or cave, circular filters incorporating a lip seal have been developed which enable the filters to be sealed into the facility without recourse to clamping. For smaller cells, a range of push-through filter change systems have been developed, the principal feature being that the filter is passed into the housing from the clean side, but transferred from the housing directly into the cell for subsequent disposal. For plant room applications, circular bag change canister systems have been developed which ease the sealing and bag change operation. Such systems have a rated air flow of up to 3000 m 3 /h whilst still allowing ultimate disposal via the 200 litre waste drum route without prior volume reduction of the filter inserts. (author)

Development of a hermetically sealed brushless DC motor for a J-T cryocooler

Science.gov (United States)

Joscelyn, Edwin; Hochler, Irwin; Ferri, Andrew; Rott, Heinz; Soukaris, Ted

1996-01-01

This development was sponsored by Ball Aerospace for the Cryogenic On-Orbit LongLife Active Refrigerator (COOLLAR) program. The cryocooler is designed to cool objects to 65 K and operate in space for at least 7 years. The system also imports minimal impact to the spacecraft in terms of vibration and heat. The basic Joule-Thompson cycle involves compressing a working fluid, nitrogen in this case, at near-constant temperature from 17.2 KPa to 6.89 MPa. The nitrogen is then expanded through a Joule-Thompson valve. The pure nitrogen gas must be kept clean; therefore, any contamination from motor organic materials must be eliminated. This requirement drove the design towards sealing of the motor within a titanium housing without sacrificing motor performance. It is estimated that an unsealed motor would have contributed 1.65 g of contaminants, due to the organic insulation and potting materials, over the 7-year life. This paper describes the motor electrical and mechanical design, as well as the sealing difficulties encountered, along with their solutions.

Pressure Actuated Leaf Seals for Improved Turbine Shaft Sealing

Science.gov (United States)

Grondahl, Clayton

2006-01-01

This presentation introduces a shaft seal in which leaf seal elements are constructed from slotted shim material formed and layered into a frusto-conical assembly. Limited elastic deflection of seal leaves with increasing system pressure close large startup clearance to a small, non-contacting, steady state running clearance. At shutdown seal elements resiliently retract as differential seal pressure diminishes. Large seal clearance during startup and shutdown provides a mechanism for rub avoidance. Minimum operating clearance improves performance and non-contacting operation promises long seal life. Design features of this seal, sample calculations at differential pressures up to 2400 psid and benefit comparison with brush and labyrinth seals is documented in paper, AIAA 2005 3985, presented at the Advanced Seal Technology session of the Joint Propulsion Conference in Tucson this past July. In this presentation use of bimetallic leaf material will be discussed. Frictional heating of bimetallic leaf seals during a seal rub can relieve the rub condition to some extent with a change in seal shape. Improved leaf seal rub tolerance is expected with bimetallic material.

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.)

The development of auto-sealing system for field joints of polyethylene coated pipelines

Energy Technology Data Exchange (ETDEWEB)

Okano, Yoshihiro [NKK Corp., Tsu, Mie (Japan); Shoji, Norio [NKK Corp., Yokohama (Japan); Namioka, Toshiyuki [Nippon Kokan Koji Corp., Osaka (Japan); Komura, Minoru [Nitto Denko Corp., Fukaya, Saitama (Japan)

1997-08-01

The paper describes the development of a system to create high quality, automatic sealing of field joints of polyethylene coated pipelines. The system uses a combination of electrically heated shrink sleeves and a low pressure chamber. The self-heating shrink sleeves include electric wires and heat themselves when connected to electricity. A method was developed to eliminate air trapped between the sleeve and steel pipe by shrinking the sleeves under low pressure. The low pressure condition was automatically and easily attained by using a vacuum chamber. The authors verified that the system produces high quality sealing of field joints.

Investigating the sealing capacity of a seal system in rock salt (DOPAS project)

Energy Technology Data Exchange (ETDEWEB)

Jantschik, Kyra; Moog, Helge C.; Czaikowski, Oliver; Wieczorek, Klaus [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Braunschweig (Germany)

2016-11-15

This paper describes research and development work on plugging and sealing repositories, an issue of fundamental importance for the rock salt option which represents one of the three European repository options, besides the clay rock and the crystalline rock options. The programme aims at providing experimental data needed for the theoretical analysis of the long-term sealing capacity of concrete- based sealing materials. In order to demonstrate hydro-mechanical material stability under representative load scenarios, a comprehensive laboratory testing programme is carried out. This comprises investigation of the sealing capacity of the combined seal system and impact of the so-called excavation-damaged zones (EDZ) as well as investigation of the hydro-chemical long-term stability of the seal in contact with different brines under diffusive and advective conditions. This paper presents experimental approaches and preliminary results from laboratory investigations on salt concrete and combined systems as obtained to date.

2007 NASA Seal/Secondary Air System Workshop. Volume 1

Science.gov (United States)

Steinetz, Bruce M.; Hendricks, Robert C.; Delgado, Irebert

2008-01-01

The 2007 NASA Seal/Secondary Air System workshop covered the following topics: (i) Overview of NASA's new Orion project aimed at developing a new spacecraft that will fare astronauts to the International Space Station, the Moon, Mars, and beyond; (ii) Overview of NASA's fundamental aeronautics technology project; (iii) Overview of NASA Glenn s seal project aimed at developing advanced seals for NASA's turbomachinery, space, and reentry vehicle needs; (iv) Reviews of NASA prime contractor, vendor, and university advanced sealing concepts, test results, experimental facilities, and numerical predictions; and (v) Reviews of material development programs relevant to advanced seals development. Turbine engine studies have shown that reducing seal leakage as well as high-pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin, and increase range. Turbine seal development topics covered include a method for fast-acting HPT blade tip clearance control, noncontacting low-leakage seals, intershaft seals, and a review of engine seal performance requirements for current and future Army engine platforms.

Ergonomics and safety of manual bag sealing.

NARCIS (Netherlands)

Groot, M.D. de; Bosch, T.; Eikhout, S.M.; Vink, P.

2005-01-01

A variety of seals is used to close bags. Each seal has advantages and disadvantages. For shop assistants sealing bags could be a repetitive physically demanding action. Opening and closing the bags again can cause some discomfort or annoyance for consumers. Besides, it is an activity which can

Repository Closure and Sealing Approach

International Nuclear Information System (INIS)

A.T. Watkins

2000-01-01

The scope of this analysis will be to develop the conceptual design of the closure seals and their locations in the Subsurface Facilities. The design will be based on the recently established program requirements for transitioning to the Site Recommendation (SR) design as outlined by ''Approach to Implementing the Site Recommendation Baseline'' (Stroupe 2000) and the ''Monitored Geologic Repository Project Description Document'' (CRWMS M andO 1999b). The objective of this analysis will be to assist in providing a description for the Subsurface Facilities System Description Document, Section 2 and finally to document any conclusions reached in order to contribute and provide support to the SR. This analysis is at a conceptual level and is considered adequate to support the SR design. The final closure barriers and seals for the ventilation shafts, and the north and south ramps will require these openings to be permanently sealed to limit excessive air and water inflows and prevent human intrusion. The major tasks identified with closure in this analysis are: (1) Developing the overall subsurface seal layout and identifying design and operational interfaces for the Subsurface Facilities. (2) Summarizing the general site conditions and general rock characteristic with respect to seal location and describing the seal selected. (3) Identify seal construction materials, methodology of construction and strategic locations including design of the seal and plugs. (4) Discussing methods to prevent human intrusion

Shaft and tunnel sealing considerations

International Nuclear Information System (INIS)

Kelsall, P.C.; Shukla, D.K.

1980-01-01

Much of the emphasis of previous repository sealing research has been placed on plugging small diameter boreholes. It is increasingly evident that equal emphasis should now be given to shafts and tunnels which constitute more significant pathways between a repository and the biosphere. The paper discusses differences in requirements for sealing shafts and tunnels as compared with boreholes and the implications for seal design. Consideration is given to a design approach for shaft and tunnel seals based on a multiple component design concept, taking into account the requirements for retrievability of the waste. A work plan is developed for the future studies required to advance shaft and tunnel sealing technology to a level comparable with the existing technology for borehole sealing

Auto-identification fiberoptical seal verifier

International Nuclear Information System (INIS)

Yamamoto, Yoichi; Mukaiyama, Takehiro

1998-08-01

An auto COBRA seal verifier was developed by Japan Atomic Energy Research Institute (JAERI) to provide more efficient and simpler inspection measures for IAEA safeguards. The verifier is designed to provide means of a simple, quantitative and objective judgment on in-situ verification for the COBRA seal. The equipment is a portable unit with hand-held weight and size. It can be operated by battery or AC power. The verifier reads a COBRA seal signature by using a built-in CCD camera and carries out the signature comparison procedure automatically on digital basis. The result of signature comparison is given as a YES/NO answer. The production model of the verifier was completed in July 1996. The development was carried out in collaboration with Mitsubishi Heavy Industries, Ltd. This report describes the design and functions of the COBRA seal verifier and the results of environmental and functional tests. The development of the COBRA seal verifier was carried out in the framework of Japan Support Programme for Agency Safeguards (JASPAS) as a project, JD-4 since 1981. (author)

Development of mechanical-hydraulic models for the prediction of the long-term sealing capacity of concrete based sealing materials in rock salt. Project Titel LASA

Energy Technology Data Exchange (ETDEWEB)

Czaikowski, Oliver; Dittrich, Juergen; Hertes, Uwe; Jantschik, Kyra; Wieczorek, Klaus; Zehle, Bernd

2016-08-15

The research work leading to these results has received funding from the German Federal Ministry of Economic Affairs and Energy (BMWi) under contract no. 02E11132. This report presents the current state of laboratory investigations and modelling activities related to the LASA project. The work is related to the research and development of plugging and sealing for repositories in salt rock and is of fundamental importance for the salt option which represents one of the three European repository options in addition to the clay rock and the crystalline rock options.

Magnetically Actuated Seal, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — FTT proposes development of a magnetically actuated dynamic seal. Dynamic seals are used throughout the turbopump in high-performance, pump-fed, liquid rocket...

Magnetically Actuated Seal, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — FTT proposes development of a magnetically actuated dynamic seal. Dynamic seals are used throughout the turbopump in high-performance, pump-fed, liquid rocket...

Development of sealed radioactive sources immobilized in epoxy resin for verification of detectors used in nuclear medicine

International Nuclear Information System (INIS)

Tiezzi, Rodrigo

2016-01-01

The radioactive sealed sources are used in verification ionization chamber detectors, which measure the activity of radioisotopes used in several areas, such as in nuclear medicine. The measurement of the activity of radioisotopes must be made with accuracy, because it is administered to a patient. To ensure the proper functioning of the ionization chamber detectors, standardized tests are set by the International Atomic Energy Agency (IAEA) and the National Nuclear Energy Commission using sealed radioactive sources of Barium-133, Cesium-137 and Cobalt-57. The tests assess the accuracy, precision, reproducibility and linearity of response of the equipment. The focus of this work was the study and the development of these radioactive sources with standard Barium-133 and Cesium-137,using a polymer, in case commercial epoxy resin of diglycidyl ether of bisphenol A (DGEBA) and a curing agent based on modified polyamine diethylenetriamine (DETA), to immobilize the radioactive material. The polymeric matrix has the main function of fix and immobilize the radioactive contents not allowing them to leak within the technical limits required by the standards of radiological protection in the category of characteristics of a sealed source and additionally have the ability to retain the emanation of any gases that may be formed during the manufacture process and the useful life of this artifact. The manufacturing process of a sealed source standard consists of the potting ,into bottle standardized geometry, in fixed volume of a quantity of a polymeric matrix within which is added and dispersed homogeneously to need and exact amount in activity of the radioactive materials standards. Accordingly, a study was conducted for the choice of epoxy resin, analyzing its characteristics and properties. Studies and tests were performed, examining the maximum miscibility of the resin with the water (acidic solution, simulating the conditions of radioactive solution), loss of mechanical and

2005 NASA Seal/Secondary Air System Workshop, Volume 1

Science.gov (United States)

Steinetz, Bruce M. (Editor); Hendricks, Robert C. (Editor)

2006-01-01

The 2005 NASA Seal/Secondary Air System workshop covered the following topics: (i) Overview of NASA s new Exploration Initiative program aimed at exploring the Moon, Mars, and beyond; (ii) Overview of the NASA-sponsored Propulsion 21 Project; (iii) Overview of NASA Glenn s seal project aimed at developing advanced seals for NASA s turbomachinery, space, and reentry vehicle needs; (iv) Reviews of NASA prime contractor, vendor, and university advanced sealing concepts including tip clearance control, test results, experimental facilities, and numerical predictions; and (v) Reviews of material development programs relevant to advanced seals development. Turbine engine studies have shown that reducing high-pressure turbine (HPT) blade tip clearances will reduce fuel burn, lower emissions, retain exhaust gas temperature margin, and increase range. Several organizations presented development efforts aimed at developing faster clearance control systems and associated technology to meet future engine needs. The workshop also covered several programs NASA is funding to develop technologies for the Exploration Initiative and advanced reusable space vehicle technologies. NASA plans on developing an advanced docking and berthing system that would permit any vehicle to dock to any on-orbit station or vehicle. Seal technical challenges (including space environments, temperature variation, and seal-on-seal operation) as well as plans to develop the necessary "androgynous" seal technologies were reviewed. Researchers also reviewed tests completed for the shuttle main landing gear door seals.

Miniature magnetic fluid seal working in liquid environments

Energy Technology Data Exchange (ETDEWEB)

Mitamura, Yoshinori, E-mail: ymitamura@par.odn.ne.jp [Graduate School of Information Science and Technology, Hokkaido University, Sapporo 060-0814 (Japan); Durst, Christopher A., E-mail: chris@procyrion.com [Procyrion, Inc., Houston, TX 77027 (United States)

2017-06-01

This study was carried out to develop a miniature magnetic fluid (MF) seal working in a liquid environment. The miniature MF seal is intended for use in a catheter blood pump. The requirements for the MF seal included a size of less than Ø4×4.5 mm, shaft diameter of 1 mm, sealing pressure of 200 mmHg, shaft speed of up to 40000 rpm, and life of one month. The miniature MF seal was composed of an NdFeB magnet (Ø4×Ø2×1) sandwiched between two pole pieces (Ø4×Ø1.1×0.5). A shield (Ø4×Ø1.2×1.5) was placed on the pole piece facing the liquid to minimize the influence of pump flow on the MF. The seal was installed on a Ø1 shaft. A seal was formed by injecting MF (Ms: 47.8 kA/m and η: 0.5 Pa·sec) into the gap between the pole pieces and the shaft. Total volume of the MF seal was 44 μL. A sealing pressure of 370 mmHg was obtained at motor speeds of 0-40,000 rpm. The seal remained perfect for 10 days in saline under the condition of a pump flow of 1.5 L/min (The test was terminated in accordance with plans). The seal remained intact after ethylene oxide sterilization during which the seal was exposed to high pressures. In conclusion, the newly developed MF seal will be useful for a catheter pump. - Highlights: • A miniature magnetic fluid seal working in a liquid environment was developed. • The seal can be installed on Ø1 mm shaft and can seal against 370 mmHg at 40000 rpm. • The magnetic fluid seal will be useful for a catheter blood pump.

Innovative Seals for Solid Oxide Fuel Cells (SOFC)

Energy Technology Data Exchange (ETDEWEB)

Singh, Raj

2008-06-30

A functioning SOFC requires different type of seals such as metal-metal, metal-ceramic, and ceramic-ceramic. These seals must function at high temperatures between 600--900{sup o}C and in oxidizing and reducing environments of the fuels and air. Among the different type of seals, the metal-metal seals can be readily fabricated using metal joining, soldering, and brazing techniques. However, the metal-ceramic and ceramic-ceramic seals require significant research and development because the brittle nature of ceramics/glasses can lead to fracture and loss of seal integrity and functionality. Consequently, any seals involving ceramics/glasses require a significant attention and technology development for reliable SOFC operation. This final report is prepared to describe the progress made in the program on the needs, approaches, and performance of high temperature seals for SOFC. In particular, a new concept of self-healing glass seals is pursued for making seals between metal-ceramic material combinations, including some with a significant expansion mismatch.

Turbine Seal Research at NASA GRC

Science.gov (United States)

Proctor, Margaret P.; Steinetz, Bruce M.; Delgado, Irebert R.; Hendricks, Robert C.

2011-01-01

Low-leakage, long-life turbomachinery seals are important to both Space and Aeronautics Missions. (1) Increased payload capability (2) Decreased specific fuel consumption and emissions (3) Decreased direct operating costs. NASA GRC has a history of significant accomplishments and collaboration with industry and academia in seals research. NASA's unique, state-of-the-art High Temperature, High Speed Turbine Seal Test Facility is an asset to the U.S. Engine / Seal Community. Current focus is on developing experimentally validated compliant, non-contacting, high temperature seal designs, analysis, and design methodologies to enable commercialization.

Spray sealing: A breakthrough in integral fuel tank sealing technology

Science.gov (United States)

Richardson, Martin D.; Zadarnowski, J. H.

1989-11-01

In a continuing effort to increase readiness, a new approach to sealing integral fuel tanks is being developed. The technique seals potential leak sources by spraying elastomeric materials inside the tank cavity. Laboratory evaluations project an increase in aircraft supportability and reliability, an improved maintainability, decreasing acquisition and life cycle costs. Increased usable fuel volume and lower weight than conventional bladders improve performance. Concept feasibility was demonstrated on sub-scale aircraft fuel tanks. Materials were selected by testing sprayable elastomers in a fuel tank environment. Chemical stability, mechanical properties, and dynamic durability of the elastomer are being evaluated at the laboratory level and in sub-scale and full scale aircraft component fatigue tests. The self sealing capability of sprayable materials is also under development. Ballistic tests show an improved aircraft survivability, due in part to the elastomer's mechanical properties and its ability to damp vibrations. New application equipment, system removal, and repair methods are being investigated.

Unification of reactor elastomeric sealing based on material

International Nuclear Information System (INIS)

Sinha, N.K.; Raj, Baldev

2012-01-01

The unification of elastomeric sealing applications of Indian nuclear reactors based on a few qualified fluoroelastomer/perfluoroelastomer compounds and standardized approaches for finite element analysis (FEA) based design, manufacturing process and antifriction coatings is discussed. It is shown that the advance polymer architecture based Viton ® formulation developed for inflatable seals of 500 MWe Prototype Fast Breeder Reactor (PFBR) and its four basic variations can encompass other sealing applications of PFBR with minimum additional efforts on development and validation. Changing the blend ratio of Viton ® GBL 200S and 600S in inflatable seal formulation could extend its use to Pressurized Heavy Water Reactors (PHWRs). The higher operating temperature of Advanced Heavy Water Reactor (AHWR) seals expands the choice to perfluoroelastomers. FEA based on plane-strain/axisymmetric modeling (with Mooney–Rivlin as the basic constitutive model), seal manufacture by cold feed extrusion and injection molding as well as plasma Teflon-like coating belonging to two variations obtained from the development of inflatable seals provide the necessary standardization for unification. The gains in simplification of design, development and operation of seals along with the enhancements of safety and reliability are expected to be substantial.

Mechanical seals

CERN Document Server

Mayer, E

1977-01-01

Mechanical Seals, Third Edition is a source of practical information on the design and use of mechanical seals. Topics range from design fundamentals and test rigs to leakage, wear, friction and power, reliability, and special designs. This text is comprised of nine chapters; the first of which gives a general overview of seals, including various types of seals and their applications. Attention then turns to the fundamentals of seal design, with emphasis on six requirements that must be considered: sealing effectiveness, length of life, reliability, power consumption, space requirements, and c

Sealing device

Science.gov (United States)

Garcia-Crespo, Andres Jose

2013-12-10

A sealing device for sealing a gap between a dovetail of a bucket assembly and a rotor wheel is disclosed. The sealing device includes a cover plate configured to cover the gap and a retention member protruding from the cover plate and configured to engage the dovetail. The sealing device provides a seal against the gap when the bucket assemply is subjected to a centrifugal force.

Steam Turbine Flow Path Seals (a Review)

Science.gov (United States)

Neuimin, V. M.

2018-03-01

Various types of shroud, diaphragm, and end seals preventing idle leak of working steam are installed in the flow paths of steam turbine cylinders for improving their efficiency. Widely known labyrinth seals are most extensively used in the Russian turbine construction industry. The category of labyrinth seals also includes seals with honeycomb inserts. The developers of seals with honeycomb inserts state that the use of such seals makes it possible to achieve certain gain due to smaller leaks of working fluid and more reliable operation of the system under the conditions in which the rotor rotating parts may rub against the stator elements. However, a positive effect can only be achieved if the optimal design parameters of the honeycomb structure are fulfilled with due regard to the specific features of its manufacturing technology and provided that this structure is applied in a goal-seeking manner in the seals of steam and gas turbines and compressors without degrading their vibration stability. Calculated and preliminary assessments made by experts testify that the replacement of conventional labyrinth seals by seals with honeycomb inserts alone, due to which the radial gaps in the shroud seal can be decreased from 1.5 to 0.5 mm, allows the turbine cylinder efficiency to be increased at the initial stage by approximately 1% with the corresponding gain in the turbine set power output. The use of rectangular-cellular seals may result, according to estimates made by their developers, in a further improvement of turbine efficiency by 0.5-1.0%. The labor input required to fabricate such seals is six to eight times smaller than that to fabricate labyrinth seals with honeycomb inserts. Recent years have seen the turbine construction companies of the United States and Germany advertising the use of abradable (sealing) coatings (borrowed from the gas turbine construction technology) in the turbine designs instead of labyrinth seals. The most efficient performance of

Upgrading elastomer seals for nuclear service

Energy Technology Data Exchange (ETDEWEB)

Wittich, K C; Wensel, R; LaRose, R; Kuran, S

1995-06-01

Pumps, valves and instruments in nuclear plants have historically contained whatever elastomer each equipment supplier traditionally used for corresponding non-nuclear service. The proliferation of elastomer compounds, and their sometimes uncertain reliability, is now being reduced by upgrading and standardizing on a handful of compounds that have each been verified to be high performers for their class of service conditions. The objective is to make cost-effective improvements in the reliability and integrity of equipment in Canadian-designed nuclear plants. The effort focuses on elastomer seals and includes: understanding sealing fundamentals, developing relevant data for superior compounds for each service, and improving quality assurance methods, including handling and inspection guidelines. In practice, discussions with plant personnel and review of plant records are the first step. Two severe-service examples are given where these needs have been met by the following progression of activities: inspecting and laboratory testing of seals removed from service, preliminary and qualification testing of improvements, introduction into service, and monitoring the upgraded seals during phase-in periods. Large gains in reliability and integrity have been demonstrated for simulated normal and accident service conditions of heat, radiation and other deteriorative influences. Significant savings in maintenance costs are also projected. (author). 2 refs., 6 figs.

Upgrading elastomer seals for nuclear service

International Nuclear Information System (INIS)

Wittich, K.C.; Wensel, R.; LaRose, R.; Kuran, S.

1995-06-01

Pumps, valves and instruments in nuclear plants have historically contained whatever elastomer each equipment supplier traditionally used for corresponding non-nuclear service. The proliferation of elastomer compounds, and their sometimes uncertain reliability, is now being reduced by upgrading and standardizing on a handful of compounds that have each been verified to be high performers for their class of service conditions. The objective is to make cost-effective improvements in the reliability and integrity of equipment in Canadian-designed nuclear plants. The effort focuses on elastomer seals and includes: understanding sealing fundamentals, developing relevant data for superior compounds for each service, and improving quality assurance methods, including handling and inspection guidelines. In practice, discussions with plant personnel and review of plant records are the first step. Two severe-service examples are given where these needs have been met by the following progression of activities: inspecting and laboratory testing of seals removed from service, preliminary and qualification testing of improvements, introduction into service, and monitoring the upgraded seals during phase-in periods. Large gains in reliability and integrity have been demonstrated for simulated normal and accident service conditions of heat, radiation and other deteriorative influences. Significant savings in maintenance costs are also projected. (author). 2 refs., 6 figs

Upgrading elastomer seals for nuclear service

International Nuclear Information System (INIS)

Wittich, K.C.; Wensel, R.; Larose, R.; Kuran, S.

1998-01-01

Pumps, valves and instruments in nuclear plants have historically contained whatever elastomer each equipment supplier traditionally used for corresponding non-nuclear service. The proliferation of elastomer compounds, and their sometimes uncertain reliability, is now being reduced by upgrading and standardizing on a handful of compounds that have each been verified to be high performers for their class of service conditions. The objective is to make cost-effective improvements in the reliability and integrity of equipment in Canadian-designed nuclear plants. The effort focuses on elastomer seals and includes: understanding sealing fundamentals, developing relevant data for superior compounds for each service, and improving quality assurance methods, including handling and inspection guidelines. In practice, discussion with plant personnel and review of plant records are the first step. Two severe-service examples are given where these needs have been met by the following progression of activities: inspecting and laboratory testing of seals removed from service, preliminary and qualification testing of improvements, introduction into service, and monitoring the upgraded seals during phase-in periods. Large gains in reliability and integrity have been demonstrated for simulated normal and accident service conditions of heat, radiation and other deteriorative influences. Significant savings in maintenance costs are also projected. (author)

Sealing Failure Analysis on V-Shaped Sealing Rings of an Inserted Sealing Tool Used for Multistage Fracturing Processes

Directory of Open Access Journals (Sweden)

Gang Hu

2018-06-01

Full Text Available The inserted sealing tool is a critical downhole implement that is used to balance the downhole pressure in multistage fracturing operations and prevent fracturing fluid from overflow and/or backward flow. The sealing ring of an inserted sealing tool plays an important role in downhole sealing since a sealing failure would ail the fracturing operation. In order to improve the sealing performance and reduce the potential fracturing failures, this research aims to investigate the influence of V-shaped sealing ring geometries on sealing performance. Constitutive experiments of rubber materials were carried out and the parameters of the constitutive relationship of rubber materials were obtained. A two-dimensional axisymmetric model considering the sealing ring has been established and influences are investigated with considerations of various system parameters and operating conditions. It is found that the stresses concentrated at the shoulder and inner vertex of the sealing ring have direct impact on the damage of the sealing rings under operational conditions. Moreover, the sealing interference, among several other factors, greatly affects the life of the sealing ring. A new design of the sealing ring is suggested with optimized geometric parameters. Its geometric parameters are the edge height of 5 mm, the vertex angle of 90°–100°, and the interference of 0.1 mm, which show a better performance and prolonged operation life of the sealing ring.

Bingham Sealing and Application in Vacuum Clamping

Science.gov (United States)

Yao, S. M.; Teo, Wee Kin; Geng, Zunmin; Turner, Sam; Ridgway, Keith

2011-12-01

Vacuum clamping is extensively used in shell machining. In this paper a Bingham Sealing (BS) is presented and formulized based on Bingham plastic performance. The sealing capability of BS is evaluated in various cases. A new Bingham plastic is developed and the yield stress is measured. The performances of "O"ring sealing and BS with the developed Bingham plastic are compared to the static experiment. In this experiment the same vacuum is achieved and the distortion of the blade with BS is better than that with "O" ring sealing.

Bingham Sealing and Application in Vacuum Clamping

International Nuclear Information System (INIS)

Yao, S M; Teo, Wee Kin; Geng Zunmin; Turner, Sam; Ridgway, Keith

2011-01-01

Vacuum clamping is extensively used in shell machining. In this paper a Bingham Sealing (BS) is presented and formulized based on Bingham plastic performance. The sealing capability of BS is evaluated in various cases. A new Bingham plastic is developed and the yield stress is measured. The performances of Or ing sealing and BS with the developed Bingham plastic are compared to the static experiment. In this experiment the same vacuum is achieved and the distortion of the blade with BS is better than that with 'O' ring sealing.

Turbine and Structural Seals Team Facilities

Data.gov (United States)

Federal Laboratory Consortium — Seals Team Facilities conceive, develop, and test advanced turbine seal concepts to increase efficiency and durability of turbine engines. Current projects include...

WIPP shaft seal system parameters recommended to support compliance calculations

International Nuclear Information System (INIS)

Hurtado, L.D.; Knowles, M.K.; Kelley, V.A.; Jones, T.L.; Ogintz, J.B.; Pfeifle, T.W.

1997-12-01

The US Department of Energy plans to dispose of transuranic waste at the Waste Isolation Pilot Plant (WIPP), which is sited in southeastern New Mexico. The WIPP disposal facility is located approximately 2,150 feet (650 m) below surface in the bedded halite of the Salado Formation. Prior to initiation of disposal activities, the Department of Energy must demonstrate that the WIPP will comply with all regulatory requirements. Applicable regulations require that contaminant releases from the WIPP remain below specified levels for a period of 10,000 years. To demonstrate that the WIPP will comply with these regulations, the Department of Energy has requested that Sandia National Laboratories develop and implement a comprehensive performance assessment of the WIPP repository for the regulatory period. This document presents the conceptual model of the shaft sealing system to be implemented in performance assessment calculations conducted in support of the Compliance Certification Application for the WIPP. The model was developed for use in repository-scale calculations and includes the seal system geometry and materials to be used in grid development as well as all parameters needed to describe the seal materials. These calculations predict the hydrologic behavior of the system. Hence conceptual model development is limited to those processes that could impact the fluid flow through the seal system

WIPP shaft seal system parameters recommended to support compliance calculations

Energy Technology Data Exchange (ETDEWEB)

Hurtado, L.D.; Knowles, M.K. [Sandia National Labs., Albuquerque, NM (United States); Kelley, V.A.; Jones, T.L.; Ogintz, J.B. [INTERA Inc., Austin, TX (United States); Pfeifle, T.W. [RE/SPEC, Inc., Rapid City, SD (United States)

1997-12-01

The US Department of Energy plans to dispose of transuranic waste at the Waste Isolation Pilot Plant (WIPP), which is sited in southeastern New Mexico. The WIPP disposal facility is located approximately 2,150 feet (650 m) below surface in the bedded halite of the Salado Formation. Prior to initiation of disposal activities, the Department of Energy must demonstrate that the WIPP will comply with all regulatory requirements. Applicable regulations require that contaminant releases from the WIPP remain below specified levels for a period of 10,000 years. To demonstrate that the WIPP will comply with these regulations, the Department of Energy has requested that Sandia National Laboratories develop and implement a comprehensive performance assessment of the WIPP repository for the regulatory period. This document presents the conceptual model of the shaft sealing system to be implemented in performance assessment calculations conducted in support of the Compliance Certification Application for the WIPP. The model was developed for use in repository-scale calculations and includes the seal system geometry and materials to be used in grid development as well as all parameters needed to describe the seal materials. These calculations predict the hydrologic behavior of the system. Hence conceptual model development is limited to those processes that could impact the fluid flow through the seal system.

Sealed radioactive sources toolkit

International Nuclear Information System (INIS)

Mac Kenzie, C.

2005-09-01

The IAEA has developed a Sealed Radioactive Sources Toolkit to provide information to key groups about the safety and security of sealed radioactive sources. The key groups addressed are officials in government agencies, medical users, industrial users and the scrap metal industry. The general public may also benefit from an understanding of the fundamentals of radiation safety

Development of sealed sheet sources for calibration of whole-body counters

International Nuclear Information System (INIS)

Miyamoto, Mai; Ishigure, Nobuhito; Ogata, Yoshimune; Narita, Norihiko; Kawaura, Chiyo; Nakano, Takashi

2009-01-01

Whole body counters are usually calibrated with the aid of a whole body phantom assembled with simply-shaped plastic vessels that are filled with an aqueous solution of the relevant radioisotopes. Most vessel-type phantoms represent only a human body in which radioisotopes are homogeneously distributed, whereas the radioisotopes in vivo are sometimes localized to specific organs. Each set of the vessels is usually applicable only to a specific combination of radioisotopes, because the replacement of radioisotopes requires troublesome procedures. Possible leakage of the solution is another disadvantage of the vessel-type phantom. The authors are developing a new-type calibration phantom that is free from these disadvantages, in which sealed sheet sources are sandwiched between sections of a sliced anthropomorphic phantom. This paper describes a method to prepare sealed sheet sources for this calibration phantom. Instead of γ-ray emitters a pure β-ray emitter 32 P was used. This isotope is suitable for autoradiography and is easy to handle as its half-life is relatively short. An ink-jet printer was used to spread the solution of 32 P mixed with ink on a sheet of paper. The surface concentration of radioactivity was regulated by the function of color density adjustment of an image processing software. The radioisotope-printed paper was laminated for sealing. Through the measurement of surface concentration of radioactivity with a liquid scintillation counter, the autoradiographical investigation of the pattern of the radioactivity distributed on the sheet sources, the immersion test of the sealed sheet sources and the monitoring of the concentration of 32 P in air during the printing, it was demonstrated that sealed sheet sources for the calibration phantom can be prepared safely by the method described in this paper. Furthermore, by using sheet sources of 99m Tc prepared as a trial it was confirmed that discrete arrangement of sheet sources in a phantom at a

Failure analysis and seal life prediction for contacting mechanical seals

Science.gov (United States)

Sun, J. J.; He, X. Y.; Wei, L.; Feng, X.

2008-11-01

Fault tree analysis method was applied to quantitatively investigate the causes of the leakage failure of mechanical seals. It is pointed out that the change of the surface topography is the main reasons causing the leakage of mechanical seals under the condition of constant preloads. Based on the fractal geometry theory, the relationship between the surface topography and working time were investigated by experiments, and the effects of unit load acting on seal face on leakage path in a mechanical seal were analyzed. The model of predicting seal life of mechanical seals was established on the basis of the relationship between the surface topography and working time and allowable leakage. The seal life of 108 mechanical seal operating at the system of diesel fuel storage and transportation was predicted and the problem of the condition monitoring for the long-period operation of mechanical seal was discussed by this method. The research results indicate that the method of predicting seal life of mechanical seals is feasible, and also is foundation to make scheduled maintenance time and to achieve safe-reliability and low-cost operation for industrial devices.

The CANDU irradiated fuel safeguards sealing system at the threshold of implementation

International Nuclear Information System (INIS)

Stirling, A.J.; Kupca, S.; Martin, R.E.; West, R.J.; Aikens, A.E.; Cox, C.A.; White, B.F.; Smith, M.T.; Payne, W.E.

1985-07-01

The development of a safeguards containment and surveillance system for the irradiated fuel discharged from CANDU nuclear generating stations has inspired the development of three different sealing technologies. Each seal type utilizes a random seal identity of different design. The AECL Random Coil (ARC) Seal combines the identity and integrity elements in the ultrasonic signature of a wire coil. Two variants of an optical seal have been developed which features identity elements of crystalline zirconium and aluminum. The sealed cap-seal uses a conventional IAEA 'Type X Seal' (wire seal). The essential features and relative merits of each seal design are described

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

diameter, high temperature seals of PFBR are indicated along with the envisaged activities en-route the production of perfected reactor inflatable seals.

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

other large diameter, high temperature seals of PFBR are indicated along with the envisaged activities en-route the production of perfected reactor inflatable seals.

Mechanical seal assembly

Science.gov (United States)

Kotlyar, Oleg M.

2001-01-01

An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transferring it to the mechanical diode.

Mechanical Seal Assembly

Energy Technology Data Exchange (ETDEWEB)

Kotlyar, Oleg M.

1999-06-18

An improved mechanical seal assembly is provided for sealing rotating shafts with respect to their shaft housings, wherein the rotating shafts are subject to substantial axial vibrations. The mechanical seal assembly generally includes a rotating sealing ring fixed to the shaft, a non-rotating sealing ring adjacent to and in close contact with the rotating sealing ring for forming an annular seal about the shaft, and a mechanical diode element that applies a biasing force to the non-rotating sealing ring by means of hemispherical joint. The alignment of the mechanical diode with respect to the sealing rings is maintained by a series of linear bearings positioned axially along a desired length of the mechanical diode. Alternative embodiments include mechanical or hydraulic amplification components for amplifying axial displacement of the non-rotating sealing ring and transferring it to the mechanical diode.

Analysis of end-face seals by FEM

Directory of Open Access Journals (Sweden)

Juraszek J.

2002-09-01

Full Text Available The end face-seals joint simultaneously the function of seal, bearing and heat exchanger. In order to improve the design of end-face seals the analysis of this type of joint by means of finite element method, was developed. The temperature distribution is indispensable to the analysis of displacement and stress in this type of face seal. In this work the values of temperature and stress in end-face seals were calculated. The numerical results were confirmed by measurements in the laboratory.

Multi-Canister overpack sealing configuration

International Nuclear Information System (INIS)

SMITH, K.E.

1998-01-01

The Spent Nuclear Fuel (SNF) position regarding the Multi-Canister Overpack (MCO) sealing configuration is to initially rely on an American Society of Mechanical Engineers (ASME) Section III Subsection NB code compliant mechanical closure/sealing system to quickly and safely establish and maintain full confinement of radioactive materials prior to and during MCO fuel drying activities. Previous studies have shown the mechanical seal to be the preferred closure method, based on dose, cost, and schedule considerations. The cost and schedule impacts of redesigning the mechanical closure to a welded shield plug do not support changing the closure system. The SNF Project has determined that the combined mechanical/welded closure system meets or exceeds the regulatory requirements to provide redundant seals while accommodating key safety and schedule limitations that are unique to K Basins fuel removal effort

The cool seal system: a practical solution to the shaft seal problem and heat related complications with implantable rotary blood pumps.

Science.gov (United States)

Yamazaki, K; Mori, T; Tomioka, J; Litwak, P; Antaki, J F; Tagusari, O; Koyanagi, H; Griffith, B P; Kormos, R L

1997-01-01

A critical issue facing the development of an implantable, rotary blood pump is the maintenance of an effective seal at the rotating shaft. Mechanical seals are the most versatile type of seal in wide industrial applications. However, in a rotary blood pump, typical seal life is much shorter than required for chronic support. Seal failure is related to adhesion and aggregation of heat denatured blood proteins that diffuse into the lubricating film between seal faces. Among the blood proteins, fibrinogen plays an important role due to its strong propensity for adhesion and low transition temperature (approximately 50 degrees C). Once exposed to temperature exceeding 50 degrees C, fibrinogen molecules fuse together by multi-attachment between heat denatured D-domains. This quasi-polymerized fibrin increases the frictional heat, which proliferates the process into seal failure. If the temperature of the seal faces is maintained well below 50 degrees C, a mechanical seal would not fail in blood. Based on this "Cool-Seal" concept, we developed a miniature mechanical seal made of highly thermally conductive material (SiC), combined with a recirculating purge system. A large supply of purge fluid is recirculated behind the seal face to augment convective heat transfer to maintain the seal temperature below 40 degrees C. It also cools all heat generating pump parts (motor coil, bearing, seal). The purge consumption has been optimized to virtually nil (seal system has now been incorporated into our intraventricular axial flow blood pump (IVAP) and newly designed centrifugal pump. Ongoing in vivo evaluation of these systems has demonstrated good seal integrity for more than 160 days. The Cool-Seal system can be applied to any type of rotary blood pump (axial, diagonal, centrifugal, etc.) and offers a practical solution to the shaft seal problem and heat related complications, which currently limit the use of implantable rotary blood pumps.

11-FFTF-LMFBR seal-test program, January-March 1976

International Nuclear Information System (INIS)

Steele, O.P. III; Horton, P.; Shimazaki, T.

1976-01-01

Current activities include providing CRBRP design information based on tests of the IVHM Inflatable Seal to CRBRP conditions, testing the CRBRP dip seal configuration to determine its performance characteristics, and delineating the effects of sodium and radiation environments on the efficiencies of various seal materials

Rotary plug seal

International Nuclear Information System (INIS)

Ito, Koji; Abiko, Yoshihiro.

1981-01-01

Purpose: To enable fuel exchange even upon failure of regular seals and also to enable safety seal exchange by the detection of the reduction in the contact pressure of a rotary plug seal. Constitution: If one of a pair of regular tube seals for the rotary plug is failed during ordinary operation of a FBR type reactor, the reduction in the contact pressure of the seal to the plug gibbousness is detected by a pressure gauge and a solenoid valve is thereby closed. Thus, a back-up-tube seal provided above or below the tube seal is press-contacted by way of argon gas to the gibbousness to enter into operation state and lubricants are supplied from an oil tank. In such a structure, the back-up-tube seal is operated before the failure of the tube seal to enable to continue the fuel exchange work, as well as safety exchange for the tube seal. (Moriyama, K.)

Development, production, and application of sealed-off copper and gold vapour lasers

International Nuclear Information System (INIS)

Lyabin, Nikolai A; Chursin, A D; Ugol'nikov, S A; Koroleva, M E; Kazaryan, M A

2001-01-01

An analysis is made of the current state of the art of scientific and engineering advances in the field of repetitively pulsed self-heating metal vapour (copper and gold) lasers based on industrial, sealed-off, high-temperature, metalceramic and metal-glass active elements. The major applications of these lasers are discussed. The energy, spatial, and time characteristics of the lasers and their dependence on the parameters and construction of the laser active elements (tubes) and optical resonators are considered. The ways for the development of new high-power industrial laser active elements with a high efficiency (1 - 2%) and a service life of 500 - 1000 h are analysed. An average output power of 80 W was realised with a laser tube 150 cm in length and 32 mm in diameter. When the pumping efficiency is improved by raising the voltage to 30 - 35 kV, this system in a copper vapour laser will allow an output power of 100 W to be obtained with one active element. The characteristics of industrial versions of metal vapour lasers manufactured in different countries are compared and discussed. (invited paper)

Miniature magnetic fluid seal working in liquid environments

Science.gov (United States)

Mitamura, Yoshinori; Durst, Christopher A.

2017-06-01

This study was carried out to develop a miniature magnetic fluid (MF) seal working in a liquid environment. The miniature MF seal is intended for use in a catheter blood pump. The requirements for the MF seal included a size of less than Ø4×4.5 mm, shaft diameter of 1 mm, sealing pressure of 200 mmHg, shaft speed of up to 40000 rpm, and life of one month. The miniature MF seal was composed of an NdFeB magnet (Ø4×Ø2×1) sandwiched between two pole pieces (Ø4×Ø1.1×0.5). A shield (Ø4×Ø1.2×1.5) was placed on the pole piece facing the liquid to minimize the influence of pump flow on the MF. The seal was installed on a Ø1 shaft. A seal was formed by injecting MF (Ms: 47.8 kA/m and η: 0.5 Pa·sec) into the gap between the pole pieces and the shaft. Total volume of the MF seal was 44 μL. A sealing pressure of 370 mmHg was obtained at motor speeds of 0-40,000 rpm. The seal remained perfect for 10 days in saline under the condition of a pump flow of 1.5 L/min (The test was terminated in accordance with plans). The seal remained intact after ethylene oxide sterilization during which the seal was exposed to high pressures. In conclusion, the newly developed MF seal will be useful for a catheter pump.

Silicone foam for penetration seal

International Nuclear Information System (INIS)

Hoshino, Yoshikazu

1986-01-01

In nuclear power plants or general buildings, it is very important to form a fire-resistant seal around cables, cable trays and conduits passing through a wall or a floor. Rockwool, asbestos, glasswool and flame-retarded urethane foam have so far been used for these purposes. However, they were not satisfactory in sealing property, workability and safety. The silicone foam newly developed, ''TOSSEAL'' 300, has cleared these defects. It has now come to be used for fire resistant seal in nuclear power plants. (author)

Electronic self-monitoring seal

International Nuclear Information System (INIS)

Campbell, J.W.

1978-01-01

The Electronic Self-Monitoring Seal is a new type of security seal which allows continuous verification of the seal's identity and status. The identity information is a function of the individual seal, time, and seal integrity. A description of this seal and its characteristics are presented. Also described are the use cycle for the seal and the support equipment for programming and verifying the seal

Inboard seal mounting

Science.gov (United States)

Hayes, John R. (Inventor)

1983-01-01

A regenerator assembly for a gas turbine engine has a hot side seal assembly formed in part by a cast metal engine block having a seal recess formed therein that is configured to supportingly receive ceramic support blocks including an inboard face thereon having a regenerator seal face bonded thereto. A pressurized leaf seal is interposed between the ceramic support block and the cast metal engine block to bias the seal wear face into sealing engagement with a hot side surface of a rotary regenerator matrix.

Security seal

Science.gov (United States)

Gobeli, Garth W.

1985-01-01

Security for a package or verifying seal in plastic material is provided by a print seal with unique thermally produced imprints in the plastic. If tampering is attempted, the material is irreparably damaged and thus detectable. The pattern of the imprints, similar to "fingerprints" are recorded as a positive identification for the seal, and corresponding recordings made to allow comparison. The integrity of the seal is proved by the comparison of imprint identification records made by laser beam projection.

Improving tag/seal technologies: the vulnerability assessment component

International Nuclear Information System (INIS)

Jones, J.L.

1996-01-01

The Department of Energy (DOE), specifically the Office of Nonproliferation and National Security, has sponsored the development of numerous tag and seal technologies for high-security/high-valued applications. One important component in this technology development effort has been the continuous integration of vulnerability assessments. The Idaho National Engineering Laboratory (INEL) has been the lead laboratory for vulnerability assessments of fiber-optic-based tag/seal technologies. This paper presents a brief historical overview and the current status of the DOE high-security tag/seal development program and discusses INEL's adversarial role and assessment philosophy. Verification testing criteria used to define ''successful'' tampering attempts/attacks are discussed. Finally, the advantages of integrating a vulnerability assessment into the development of commercial security tag/seals are presented

Further development of the spindle seal on reactor valves and development for increasing serviceability

International Nuclear Information System (INIS)

Zilling, H.

1977-01-01

A literature search concerning packing glands for sealing oscillating rods was marginally profitable. In order to design single-wall siphons a programme has been developed, in which by applying boundary conditions such as range, pressure, setting - the distortion tension which occur in each section of the siphon and also its life can be calculated. In the 'serviceability' project records have been kept during the installation of dampers and valves. (orig.) [de

Technological progress in sealed lead/acid batteries

Science.gov (United States)

Yamashita, J.; Nakashima, H.; Kasai, Y.

A brief review is given of the history of the research and development of sealed lead/acid batteries during the 30 years since, in 1959, the Yuasa Battery Co. introduced a small-sized sealed battery as the power supply for portable television sets. In 1965, Yuasa began the full-scale mass production and sale of a small-sized sealed lead/acid battery under the NOYPER brand. In 1970, the use of a PbCa alloy grid was adopted, and there followed the successful development of a sealed battery with an oxygen-recombination facility. In 1976, Yuasa more or less established the basic technology for the valve-regulated sealed lead/acid battery — the NP battery — which is now the type in general use. Throughout the 1980s, Yuasa, has continued development in order to expand the sphere of application for the production technology of valve-regulated batteries for motorcycles, as well as for stationary duties with large capacities of 100 to 3000 A h. Recently, in order to improve the reliability and boost the output of sealed lead/acid batteries for employment in UPS power sources, Yuasa has been working intently on the design of a valve-regulated lead/acid battery with outstanding characteristics for high-rate discharge and resistance to high temperatures.

Mechanical seal program

International Nuclear Information System (INIS)

Lowery, G.B.

1983-01-01

The experimental plans and timing for completion of the mechanical seal program for both the slurry and transfer pumps are given. The slurry pump seal program will be completed by April 1984 with turnover of two seals in pumps to SRP Tank 15H. Transfer pump seal design will be released for plant use by May 1984. Also included are various other pump and seal related tests

An integrated approach to fire penetration seal program management

International Nuclear Information System (INIS)

Rispoli, R.D.

1996-01-01

This paper discusses the utilization of a P.C. based program to facilitate the management of Entergy Operations Arkansas Nuclear One (ANO) fire barrier penetration seal program. The computer program was developed as part of a streamlining process to consolidate all aspects of the ANO Penetration Seal Program under one system. The program tracks historical information related to each seal such as maintenance activities, design modifications and evaluations. The program is integrated with approved penetration seal design details which have been substantiated by full scale fire tests. This control feature is intended to prevent the inadvertent utilization of an unacceptable penetration detail in a field application which may exceed the parameters tested. The system is also capable of controlling the scope of the periodic surveillance of penetration seals by randomly selecting the inspection population and generating associated inspection forms. Inputs to the data base are required throughout the modification and maintenance process to ensure configuration control and maintain accurate data base information. These inputs are verified and procedurally controlled by Fire Protection Engineering (FPE) personnel. The implementation of this system has resulted in significant cost savings and has minimized the allocation of resources necessary to ensure long term program viability

Apparatus and method for inspecting a sealed container

Science.gov (United States)

Harmon, J Frank [Pocatello, ID; Jones, James L [Idaho Falls, ID; Hunt, Alan W [Pocatello, ID; Spaulding, Randy J [Pocatello, ID; Smith, Michael [Phoenix, AZ

2009-03-24

An apparatus for inspecting a sealed container is disclosed and which includes a pulsed electron accelerator which is positioned in spaced relation relative to a first side of the sealed container, and which produces a pulsed beam of photons which passes through the sealed container and any contents enclosed within the sealed container; a detector positioned in spaced relation relative to a second, opposite side of the sealed container, and which receives the pulsed beam of photons which passes through the contents of the sealed container, and which produces an output signal; and a computer for developing a visible image from the output signal of the detector which depicts the contents of the sealed container.

The use of dual material seals for packaging

International Nuclear Information System (INIS)

Temus, C.J.; Nichols, J.C.

2004-01-01

The use of dual material seals, metal and elastomeric for a transportation package, provides a viable option for packages requiring high temperature seal capability. Allowing the seal area to go to higher temperatures then allowed for all elastomeric seal reduce the necessity of providing thermal protection during a postulated accident condition fire. It also increases the options for impact limiting features that do not also mitigate the affects of accident thermal events. Typically, high temperature seals require the use of metal O-rings. Only one seal (typically identified as the containment seal) needs to survive the hypothetical accident conditions, including the high temperatures that may occur during the prescribed hypothetical thermal event. However, to expedite the assembly leakage rate testing of radioactive material packages, a dual O-ring seal arrangement is often used to allow creation of a relatively small volume test cavity between the seals. For any package that is being used on a frequent basis, the total cost of seals can be significantly reduced by using an elastomeric seal as the secondary seal. The elastomeric seal is not the containment boundary seal and does not need to survive the high temperature condition. To get the dual material O-ring seals to seat properly, a different approach has to be taken than with closure of a radioactive material package that does not use metallic O-ring(s). A metal O-ring requires an application of a seating force while the elastomeric package requires a certain percentage of deformation. This is further complicated when the seating force is developed using a multi-bolt closure. Because of the nature of multi-bolt closures, elastic interaction prevents the equal application of force. This paper develops the methods involved in properly closing and establishing containment when using dual material seals with a multi-bolt closure. These methods were demonstrated in two production casks requiring testing leak

Secondary seal effects in hydrostatic non-contact seals for reactor coolant pump shaft

International Nuclear Information System (INIS)

Fujita, T.; Koga, T.; Tanoue, H.; Hirabayashi, H.

1987-01-01

The paper presents a seal flow analysis in a hydrostatic non-contact seal for a PWR coolant pump shaft. A description is given of the non-contact seal for the reactor coolant pump. Results are presented for a distortion analysis of the seal ring, along with the seal flow characteristics and the contact pressure profiles of the secondary seals. The results of the work confirm previously reported findings that the seal ring distortion is sensitive to the o-ring location (which was placed between the ceramic seal face and the seal ring retainer). The paper concludes that the seal flow characteristics and the tracking performance depend upon the dynamic properties of the secondary seal. (U.K.)

Application of a magnetic fluid seal to rotary blood pumps

International Nuclear Information System (INIS)

Mitamura, Y; Arioka, S; Azegami, M; Sakota, D; Sekine, K

2008-01-01

A magnetic fluid seal enables mechanical contact-free rotation of a shaft without frictional heat and material wear and hence has excellent durability. However, the durability of a magnetic fluid seal decreases in liquid. The life of a seal applied to a rotary blood pump is not known. We have developed a magnetic fluid seal that has a shield mechanism minimizing the influence of the rotary pump on the magnetic fluid. The developed magnetic fluid seal worked for over 286 days in a continuous flow condition, for 24 days (on-going) in a pulsatile flow condition and for 24 h (electively terminated) in blood flow. The magnetic fluid seal is promising as a shaft seal for rotary blood pumps

Design analysis of a self-acting spiral-groove ring seal for counter-rotating shafts. [o ring seals

Science.gov (United States)

Dirusso, E.

1983-01-01

A self-acting spiral groove inter-shaft ring seal of nominal 16.33 cm (6.43 in.) diameter for sealing fan bleed air between counter rotating shafts in advanced turbofan engines was analyzed. The analysis focused on the lift force characteristics of the spiral grooves. A NASA Lewis developed computer program for predicting the performance of gas lubricated face seals was used to optimize the spiral groove geometry to produce maximum lift force. Load capacity curves (lift force as function of film thickness) were generated for four advanced turbofan engine operating conditions at relative seal speeds ranging from 17,850 to 29,800 rpm, sealed air pressures from 6 to 42 N/sq cm (9 to 60 psi) absolute and temperatures from 95 to 327 C (203 to 620 F). The relative seal sliding speed range was 152 to 255 m/sec (500 to 836 ft/sec). The analysis showed that the spiral grooves are capable of producing sufficient lift force such that the ring seal will operate in a noncontacting mode over the operating range of typical advanced turbofan engines.

Analysis of Mechanical Seals for High-Speed Centrifugal Gas Compressors

OpenAIRE

K.N. Nwaigwe; P.E. Ugwuoke; E.E. Anyanwu; D.P.S. Abam

2012-01-01

A study aimed at seal selection efficiency for centrifugal pumps in the oil and gas industry is presented. A detailed analysis of mechanical seals in use in exploration and production activities of the oil and gas sector was undertaken. The approach of analysis was using seal design equations as mathematical models for simulating the performance of the mechanical seal. The results showed a mechanical seal with balance value of 0.5, an increased surface area between mating surfaces; provided w...

Seal arrangement

International Nuclear Information System (INIS)

Dempsey, J.D.

1978-01-01

A hydraulically balanced face type shaft seal is provided in which the opening and closing seal face areas retain concentricity with each other in the event of lateral shaft displacement. The seal arrangement is for a vertical high pressure pump, indented for use in the cooling system of a nuclear reactor. (Auth.)

Seroprevalence of Antibodies against Seal Influenza A(H10N7) Virus in Harbor Seals and Gray Seals from the Netherlands.

Science.gov (United States)

Bodewes, Rogier; Rubio García, Ana; Brasseur, Sophie M; Sanchez Conteras, Guillermo J; van de Bildt, Marco W G; Koopmans, Marion P G; Osterhaus, Albert D M E; Kuiken, Thijs

2015-01-01

In the spring and summer 2014, an outbreak of seal influenza A(H10N7) virus infection occurred among harbor seals (Phoca vitulina) off the coasts of Sweden and Denmark. This virus subsequently spread to harbor seals off the coasts of Germany and the Netherlands. While thousands of seals were reported dead in Sweden, Denmark and Germany, only a limited number of seals were found dead in the Netherlands. To determine the extent of exposure of seals in the Netherlands to influenza A/H10N7 virus, we measured specific antibody titers in serum samples from live-captured seals and seals admitted for rehabilitation in the Netherlands by use of a hemagglutination inhibition assay and an ELISA. In harbor seals in 2015, antibodies against seal influenza A(H10N7) virus were detected in 41% (32 out of 78) pups, 10% (5 out of 52) weaners, and 58% (7 out of 12) subadults or adults. In gray seals (Halichoerus grypus) in 2015, specific antibodies were not found in the pups (n = 26), but in 26% (5 out of 19) of the older animals. These findings indicate that, despite apparent low mortality, infection with seal influenza A(H10N7) virus was geographically widespread and also occurred in grey seals.

Addendum to ''Test Plan: Small-Scale Seal Performance Tests (SSSPT)''

International Nuclear Information System (INIS)

Finley, R.E.

1992-01-01

This document describes activities that are intended to update the data base of fluid flow measurements made on expansive salt concrete (ESC) seals as part of the Small-Scale Seal Performance Tests (SSSPT). The original plans for the SSSPT experiments are described by Stormont (1985a and 1985b). These seals have previously been tested with brine and gas during the early stages (less than 450 days) after emplacement. The purpose of this Test Plan Addendum is to detail the activities necessary to, update the gas and brine measurements previously performed on the SSSPT Series A and Series B seals and to identify the key personnel responsible for implementing these activities. This addendum describes a limited undertaking and does NOT change the scope of the original test plan

Handling, conditioning and disposal of spent sealed sources

International Nuclear Information System (INIS)

1990-02-01

The series entitled ''Technical Manual for the Management of Low and Intermediate Level Wastes Generated at Small Nuclear Research Centres and by Radioisotope Users in Medicine, Research and Industry'' will serve as reference material to experts on technical assistance missions and provide ''direct know-how'' for technical staff in developing countries. This document is the first in the series. It provides the technical guidance and know-how necessary to permit developing Member States to safely handle, condition and store spent sealed radiation sources. It covers: characterization of sealed sources, legislation and regulations, management of spent sealed sources, transportation and disposal of spent sealed sources. 5 refs, 10 figs, 6 tabs

Coupled processes in repository sealing

International Nuclear Information System (INIS)

Case, J.B.; Kelsall, P.C.

1985-01-01

The significance of coupled processes in repository sealing is evaluated. In most repository designs, shaft seals will be located in areas of relatively low temperature perturbation, in which case the coupling of temperature with stress and permeability may be less significant than the coupling between stress and permeability that occurs during excavation. Constitutive relationships between stress and permeability are reviewed for crystalline rock and rocksalt. These provide a basis for predicting the development of disturbed zones near excavations. Field case histories of the degree of disturbance are presented for two contrasting rock types - Stripa granite and Southeastern New Mexico rocksalt. The results of field investigations in both rock types confirm that hydraulic conductivity or permeability is stress dependent, and that shaft seal performance may be related to the degree that stresses are perturbed and restored near the seal

Laparoscopic prototype for optical sealing of renal blood vessels

Science.gov (United States)

Hardy, Luke A.; Hutchens, Thomas C.; Larson, Eric R.; Gonzalez, David A.; Chang, Chun-Hung; Nau, William H.; Fried, Nathaniel M.

2017-02-01

Energy-based, radiofrequency and ultrasonic devices provide rapid sealing of blood vessels during laparoscopic procedures. We are exploring infrared lasers as an alternative for vessel sealing with less collateral thermal damage. Previous studies demonstrated vessel sealing in an in vivo porcine model using a 1470-nm laser. However, the initial prototype was designed for open surgery and featured tissue clasping and light delivery mechanisms incompatible with laparoscopic surgery. In this study, a laparoscopic prototype similar to devices in surgical use was developed, and tests were conducted on porcine renal blood vessels. The 5-mm-OD prototype featured a traditional Maryland jaw configuration. Laser energy was delivered through a 550-μm-core fiber and side-delivery from the lower jaw, with beam dimensions of 18-mm-length x 1.2-mm-width. The 1470-nm diode laser delivered 68 W with 3 s activation time. A total of 69 porcine renal vessels with mean diameter of 3.3 +/- 1.7 mm were tested, ex vivo. Vessels smaller than 5 mm were consistently sealed (48/51) with burst pressures greater than malignant hypertension blood pressure (180 mmHg), averaging 1038 +/- 474 mmHg. Vessels larger than 5 mm were not consistently sealed (6/18), yielding burst pressures of only 174 +/- 221 mmHg. Seal width, thermal damage zone, and thermal spread averaged 1.7 +/- 0.8, 3.4 +/- 0.7, and 1.0 +/- 0.4 mm. A novel optical laparoscopic prototype with 5-mm- OD shaft integrated within a standard Maryland jaw design consistently sealed vessels less than 5 mm with minimal thermal spread. Further in vivo studies are planned to test performance across a variety of vessels and tissues.

Radioactive sealed sources: Reasonable accountability, exemption, and licensing activity thresholds -- A technical basis

International Nuclear Information System (INIS)

Lee, D.W.; Shingleton, K.L.

1996-01-01

Perhaps owing to their small size and portability, some radiation accidents/incidents have involved radioactive sealed sources (RSSs). As a result, programs for the control and accountability of RSSs have come to be recommended and emplaced that essentially require RSSs to be controlled in a manner different from bulk, unsealed radioactive material. Crucially determining the total number of RSSs for which manpower-intensive radiation protection surveillance is provided is the individual RSS activity above which such surveillance is required and below which such effort is not considered cost effective. Individual RSS activity thresholds are typically determined through scenarios which impart a chosen internal or external limiting dose to Reference Man under specified exposure conditions. The resultant RSS threshold activity levels have meaning commensurate with the assumed scenario exposure parameters, i.e., if they are realistic and technically based. A review of how the Department of Energy (DOE), the International Atomic Energy Agency (IAEA), and the Nuclear Regulatory Commission (NRC) have determined their respective accountability, exemption, and licensing threshold activity values is provided. Finally, a fully explained method using references readily available to practicing health physicists is developed using realistic, technically-based calculation parameters by which RSS threshold activities may be locally generated

Seal design alternatives study

International Nuclear Information System (INIS)

Van Sambeek, L.L.; Luo, D.D.; Lin, M.S.; Ostrowski, W.; Oyenuga, D.

1993-06-01

This report presents the results from a study of various sealing alternatives for the WIPP sealing system. Overall, the sealing system has the purpose of reducing to the extent possible the potential for fluids (either gas or liquid) from entering or leaving the repository. The sealing system is divided into three subsystems: drift and panel seals within the repository horizon, shaft seals in each of the four shafts, and borehole seals. Alternatives to the baseline configuration for the WIPP seal system design included evaluating different geometries and schedules for seal component installations and the use of different materials for seal components. Order-of-magnitude costs for the various alternatives were prepared as part of the study. Firm recommendations are not presented, but the advantages and disadvantages of the alternatives are discussed. Technical information deficiencies are identified and studies are outlined which can provide required information

Enhanced sealing project (ESP): evolution of a full-sized concrete and bentonite shaft seal

International Nuclear Information System (INIS)

Dixon, D.A.; Priyanto, D.G.; Martino, J.B.; De Combarieu, M.; Johansson, R.; Korkeakoski, P.; Villagran, J.

2012-01-01

Document available in extended abstract form only. A full-scale shaft seal was designed and installed in the 5-m-diameter access shaft at Atomic Energy of Canada's (AECL's) Underground Research Laboratory (URL) at the point where he shaft intersects an ancient water-bearing, low-angle thrust fault in granitic rock. The seal, part of the permanent closure of the URL, consists of a 6-m-thick bentonite-based component sandwiched between 3-m-thick upper and lower, 3-m-thick concrete components. The bentonite-based component spans the fracture zone and extends approximately 1 m beyond the maximum identified extent of the fracture. This design was adopted in order to limit water from the deeper, saline regions mixing with the fresher, near-surface groundwater regime. The concrete components provide the mechanical confinement and an in situ compacted 40/60 mixture of bentonite clay and quartz sand provides the sealing component. Construction of the shaft seal was done as part of Canada's Nuclear Legacies Liability Program. However, monitoring the seal evolution was not part of the decommissioning program's mandate. In addition to accomplishing the permanent closure of the URL, this seal's construction provides a unique opportunity to instrument and monitor the evolution of a full-scale shaft seal as well as the recovery of the regional groundwater regime as the facility passively floods above the seal. A jointly funded monitoring project was developed by NWMO (Canada), SKB (Sweden), Posiva (Finland) and ANDRA (France) and since mid 2009 the thermal, hydraulic and mechanical evolution of the seal has been constantly monitored. The evolution of the type of seal being monitored in the ESP is of relevance to repository closure planning, gaining confidence in the functionality of shaft seals. Although constructed in a crystalline rock medium, the results of the ESP are expected to be relevant to the performance of seals in a variety of host rock types. The shaft seal has been

Safety considerations in the disposal of disused sealed radioactive sources in borehole facilities

International Nuclear Information System (INIS)

2003-08-01

Sealed radioactive sources are used in medicine, industry and research for a wide range of purposes. They can contain different radionuclides in greatly varying amounts. At the end of their useful lives, they are termed 'disused sources' but their activity levels can still be quite high. They are, for all practical purposes, another type of radioactive waste that needs to be disposed of safely. Disused sealed radioactive sources can represent a significant hazard to people if not managed properly. Many countries have no special facilities for the management or disposal of radioactive waste, as they have no nuclear power programmes requiring such facilities. Even in countries with developed nuclear programmes, disused sealed sources present problems as they often fall outside the common categories of radioactive waste for which disposal options have been identified. As a result, many disused sealed sources are kept in storage. Depending on the nature of the storage arrangements, this situation may represent a high potential risk to workers and to the public. The IAEA has received numerous requests for assistance from Member States faced with the problem of safely managing disused sealed sources. The requests have related to both technical and safety aspects. Particularly urgent requests have involved emergency situations arising from unsafe storage conditions and lost sources. There is therefore an important requirement for the development of safe and cost-effective final disposal solutions. Consequently, a number of activities have been initiated by the IAEA to assist Member States in the management of disused sealed sources. The objective of this report is to address safety issues relevant to the disposal of disused sealed sources, and other limited amounts of radioactive waste, in borehole facilities. It is the first in a series of reports aiming to provide an indication of the present issues related to the use of borehole disposal facilities to safely disposal

Application study of magnetic fluid seal in hydraulic turbine

International Nuclear Information System (INIS)

Yu, Z Y; Zhang, W

2012-01-01

The waterpower resources of our country are abundant, and the hydroelectric power is developed, but at present the main shaft sealing device of hydraulic turbine is easy to wear and tear and the leakage is great. The magnetic fluid seal has the advantages of no contact, no wear, self-healing, long life and so on. In this paper, the magnetic fluid seal would be used in the main shaft of hydraulic turbine, the sealing structure was built the model, meshed the geometry, applied loads and solved by using MULTIPHYSICS in ANSYS software, the influence of the various sealing structural parameters such as tooth width, height, slot width, sealing gap on the sealing property were analyzed, the magnetic fluid sealing device suitable for large-diameter shaft and sealing water was designed, the sealing problem of the hydraulic turbine main shaft was solved effectively which will bring huge economic benefits.

Leak detection of KNI seals

International Nuclear Information System (INIS)

Baranyai, G.; Peter, A.; Windberg, P.

1990-03-01

In Unit 3 and 4 of the Paks Nuclear Power Plant, Hungary, KNI type seals are used as lead-throughs with conical nickel sealing rings. Their failure can be critical for the operation of the reactor. An Acoustical Leak Detection System (ALDS) was constructed and tested for the operational testing of the seals. Some individual papers are presented in this collection on the calibration and testing of the ALDS intended to be placed on the top of the reactor vessels. The papers include simulation measurements of Unit 3 of NPP, laboratory experiments, evaluation of measurements, and further development needs with the ALDS. (R.P.) 50 figs.; 19 tabs

Properties of Sealing Materials in Groundwater Wells

DEFF Research Database (Denmark)

Köser, Claus

pellets as sealing material in groundwater wells. The way and the pattern, in which bentonite pellets are deposited, have been shown to have an effect on the swelling pressure of the bentonite seal. During the transport phase of pellets from the terrain to a given sedimentation depth, a sorting process......) into densities for clay/water systems has been developed. This method has successfully been used to evaluate e.g., macroporosity, homogenization of the bentonite seal during the hydration of water, hydraulic conductivity and the creation of channels in the bentonite seals. Based on the results obtained...

Enhanced sealing project: monitoring the THM response of a full-scale shaft seal

Energy Technology Data Exchange (ETDEWEB)

Dixon, D.A.; Martino, J.B.; Holowick, B.; Priyanto, D. [Atomic Energy of Canada Limited, Pinawa, MB (Canada)

2011-07-01

Closure of the subsurface facilities at Atomic Energy of Canada Limited's (AECL) Underground Research Laboratory (URL) was completed in 2010 with installation of a concrete surface cap. Additionally, as part of decommissioning, seals were installed at the penetration of the shafts through the major hydro-geological feature known as Fracture Zone 2 (FZ2). The seal construction was funded by Natural Resources Canada (NRCan) under the Nuclear Legacy Liabilities Program (NLLP). The shaft seals at the URL were based on the composite seal concept developed for application in a deep geological repository for disposal of used nuclear fuel. The access shaft seal consists of two 3-m thick concrete segments that rigidly confine a 6-m long section of swelling clay-based material (40% bentonite clay - 60% sand by dry mass). Monitoring of the regional groundwater recovery following flooding of the lower shaft is a closure requirement and was included in the design. It was widely recognized that the installation of the seals at the URL represented a unique opportunity to monitor the evolution of the type of seal that might be installed in an actual repository but the NLLP mandate did not include any monitoring of shaft seal evolution. As a result the Enhanced Sealing Project (ESP) partnership composed of NWMO, Posiva, SKB and ANDRA was established and a set of 68 instruments (containing 100 sensors) were installed to monitor the evolution of the seal. In the first year of operation sensors have monitored the following parameters in the ESP: thermal evolution and strain of the concrete components, thermal, hydraulic and mechanical changes in the clay component and its contacts with the rock and concrete confinement. Additionally, monitoring of the near-field and regional groundwater evolution has been undertaken. Monitoring of the short-term thermal-mechanical evolution of the concrete components was successfully accomplished and only a small temperature rise occurred due to

Enhanced sealing project: monitoring the THM response of a full-scale shaft seal

International Nuclear Information System (INIS)

Dixon, D.A.; Martino, J.B.; Holowick, B.; Priyanto, D.

2011-01-01

Closure of the subsurface facilities at Atomic Energy of Canada Limited's (AECL) Underground Research Laboratory (URL) was completed in 2010 with installation of a concrete surface cap. Additionally, as part of decommissioning, seals were installed at the penetration of the shafts through the major hydro-geological feature known as Fracture Zone 2 (FZ2). The seal construction was funded by Natural Resources Canada (NRCan) under the Nuclear Legacy Liabilities Program (NLLP). The shaft seals at the URL were based on the composite seal concept developed for application in a deep geological repository for disposal of used nuclear fuel. The access shaft seal consists of two 3-m thick concrete segments that rigidly confine a 6-m long section of swelling clay-based material (40% bentonite clay - 60% sand by dry mass). Monitoring of the regional groundwater recovery following flooding of the lower shaft is a closure requirement and was included in the design. It was widely recognized that the installation of the seals at the URL represented a unique opportunity to monitor the evolution of the type of seal that might be installed in an actual repository but the NLLP mandate did not include any monitoring of shaft seal evolution. As a result the Enhanced Sealing Project (ESP) partnership composed of NWMO, Posiva, SKB and ANDRA was established and a set of 68 instruments (containing 100 sensors) were installed to monitor the evolution of the seal. In the first year of operation sensors have monitored the following parameters in the ESP: thermal evolution and strain of the concrete components, thermal, hydraulic and mechanical changes in the clay component and its contacts with the rock and concrete confinement. Additionally, monitoring of the near-field and regional groundwater evolution has been undertaken. Monitoring of the short-term thermal-mechanical evolution of the concrete components was successfully accomplished and only a small temperature rise occurred due to

Nozzle seal

International Nuclear Information System (INIS)

Herman, R.F.

1977-01-01

In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with sealing members operatively disposed between the outlet nozzle and the hoop. The sealing members are biased against the pressure vessel and the hoop and are connected by a leak restraining member establishing a leak-proof condition between the inlet and outlet coolants in the region about the outlet nozzle. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel

Nozzle seal

International Nuclear Information System (INIS)

Walling, G.A.

1977-01-01

In an illustrative embodiment of the invention, a nuclear reactor pressure vessel, having an internal hoop from which the heated coolant emerges from the reactor core and passes through to the reactor outlet nozzles, is provided with sealing rings operatively disposed between the outlet nozzles and the hoop. The sealing rings connected by flexible members are biased against the pressure vessel and the hoop, establishing a leak-proof condition between the inlet and outlet coolants in the region about the outlet nozzle. Furthermore, the flexible responsiveness of the seal assures that the seal will not structurally couple the hoop to the pressure vessel. 4 claims, 2 figures

Flexible ring seal

International Nuclear Information System (INIS)

Abbes, Claude; Gournier, Andre; Rouaud, Christian; Villepoix, Raymond de.

1976-01-01

The invention concerns a flexible metal ring seal, able to ensure a perfect seal between two bearings due to the crushing and elastic deformation properties akin to similar properties in elastomers. Various designs of seal of this kind are already known, particularly a seal made of a core formed by a helical wire spring with close-wound turns and with high axial compression ratio, closed on itself and having the shape of an annulus. This wire ring is surrounded by at least one envelope having at rest the shape of a toroidal surface of which the generating circle does not close on itself. In a particular design mode, the seal in question can include, around the internal spring, two envelopes of which one in contact with the spring is composed of a low ductility elastic metal, such as mild steel or stainless steel and the other is, on the contrary, made of a malleable metal, such as copper or nickel. The first envelope evenly distributes the partial crushing of the spring, when the seal is tightened, on the second envelope which closely fits the two surfaces between which the seal operates. The stress-crushing curve characteristic of the seal comprises two separate parts, the first with a relatively sharp slope corresponds to the start of the seal compression phase, enabling at least some of these curves to reach the requisite seal threshold very quickly, then, beyond this, a second part, practically flat, where the stress is appreciably constant for a wide operating bracket [fr

Nuclear reactor sealing system

International Nuclear Information System (INIS)

McEdwards, J.A.

1983-01-01

A liquid metal-cooled nuclear reactor sealing system is disclosed. The nuclear reactor includes a vessel sealed at its upper end by a closure head. The closure head comprises at least two components, one of which is rotatable; and the two components define an annulus therebetween. The sealing system includes at least a first and second inflatable seal disposed in series in an upper portion of the annulus. The system further includes a dip seal extending into a body of insulation located adjacent a bottom portion of the closure head. The dip seal comprises a trough formed by a lower portion of one of the components, and a seal blade pendently supported from the other component and extending downwardly into the trough. A body of liquid metal is contained in the trough which submerges a portion of the seal blade. The seal blade is provided with at least one aperture located above the body of liquid metal for providing fluid communication between the annulus intermediate the dip seal and the inflatable seals, and a body of cover gas located inside the vessel. There also is provided means for introducing a purge gas into the annulus intermediate the inflatable seals and the seal blade. The purge gas is introduced in an amount sufficient to substantially reduce diffusion of radioactive cover gas or sodium vapor up to the inflatable seals. The purge gas mixes with the cover gas in the reactor vessel where it can be withdrawn from the vessel for treatment and recycle to the vessel

Developing reliable safeguards seals for application verification and removal by State operators

Energy Technology Data Exchange (ETDEWEB)

Finch, Robert J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Smartt, Heidi A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Haddal, Risa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-10-01

Once a geological repository has begun operations, the encapsulation and disposal of spent fuel will be performed as a continuous, industrial-scale series of processes, during which time safeguards seals will be applied to transportation casks before shipment from an encapsulation plant, and then verified and removed following receipt at the repository. These operations will occur approximately daily during several decades of Sweden's repository operation; however, requiring safeguards inspectors to perform the application, verification, and removal of every seal would be an onerous burden on International Atomic Energy Agency's (IAEA's) resources. Current IAEA practice includes allowing operators to either apply seals or remove them, but not both, so the daily task of either applying or verifying and removing would still require continuous presence of IAEA inspectors at one site at least. Of special importance is the inability to re-verify cask or canisters from which seals have been removed and the canisters emplaced underground. Successfully designing seals that can be applied, verified and removed by an operator with IAEA approval could impact more than repository shipments, but other applications as well, potentially reducing inspector burdens for a wide range of such duties.

Self-acting shaft seals

Science.gov (United States)

Ludwig, L. P.

1978-01-01

Self-acting seals are described in detail. The mathematical models for obtaining a seal force balance and the equilibrium operating film thickness are outlined. Particular attention is given to primary ring response (seal vibration) to rotating seat face runout. This response analysis reveals three different vibration models with secondary seal friction being an important parameter. Leakage flow inlet pressure drop and affects of axisymmetric sealing face deformations are discussed. Experimental data on self-acting face seals operating under simulated gas turbine conditions are given. Also a spiral groove seal design operated to 244 m/sec (800 ft/sec) is described.

HMSRP Hawaiian Monk Seal Master Identification Records (seal)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains records of all individually identified Hawaiian monk seals since 1981. These seals were identified by PSD personnel and cooperating scientists...

R I 800. A new cobalt-60 sealed source design

International Nuclear Information System (INIS)

Freijo, Jose L.; Gomez, Gonzalo

2006-01-01

The consolidation of the international market of Co-60 sources and the perspective of its growth has encouraged the development of new types of sealed sources. The model R I 800 is designed for activities up to 65 kCi and allows a large spectrum of capsules with different specific activities. During three years Dioxitek developed the process of fabrication and qualifications to comply the design requirements and succeeded in the product approval. Today, the initial lot at an industrial scale of R I 800 sources is under fabrication and a first partial shipment of 100 kCi to the United Kingdom was successfully carried out at the end of October 2005. The whole lot is for export. Due to the versatility of the R I 800 sealed sources it was possible to use as raw material 1 MCi of Co-60 imported from Russia, irradiated in Leningrad nuclear power plant. (author) [es

Tamper tape seals

International Nuclear Information System (INIS)

Wright, B.W.; Undem, H.A.

1994-07-01

Tamper tapes are appealing for many applications due to their ease of use and relative robustness. Applications include seals for temporary area denial, protection of sensitive equipment, chain-of-custody audit trails, and inventory control practices. A next generation of adhesive tamper tapes is being developed that combines the best features of commercially available devices with additional state-of-the-art features in tamper indication, tamper-resistance, and counterfeit-resistance. The additional features are based on U.S. Department of Energy (DOE) research and development (R ampersand D) activities that were originally associated with preparations for the Strategic Arms Reduction Treaty (START). New features include rapid-set, chemical-cure adhesive systems that allow user-friendly application and layered levels of counterfeit-resistance based on unique open-quotes fingerprintclose quotes characteristics that can be accessed as desired

Prototype bellows sealed nuclear valve development -reliability through testing

International Nuclear Information System (INIS)

Dixon, D.F.; Abbas, M.

1978-01-01

To assist in appraising bellows sealed valve performance, 10 tests were done on a ''1 in.'' prototype bellows sealed valve design. The tests simulated primary heat transport (PHT) system conditions for a 600 MWe CANDU-PHW. The design approach was to have all valve components outlast the bellows in endurance tests; this was achieved. The valve design meets the Atomic Energy of Canada Limited specification. For comparison, bellows fatigue failure data were fitted to both log-normal and Weibull distributions. A numerical example shows how to select valve stroke amplitude on the basis of valve flow requirement and the minimum acceptable fatigue life. (author)

Test of Seal System for Flexible Pipe End Fitting

DEFF Research Database (Denmark)

Banke, Lars; Jensen, Thomas Gregers

1999-01-01

The purpose of the end fitting seal system is to ensure leak proof termination of flexible pipes. The seal system of an NKT end fitting normally consists of a number of ring joint gaskets mounted in a steel sleeve on the outside of the polymeric inner liner of the pipe. The seal system is activated...... by compression of the gaskets, thus using the geometry to establish a seal towards the inner liner of the pipe and the steel sleeve of the end fitting. This paper describes how the seal system of an end fitting can be tested using an autoclave. By regulating temperature and pressure, the seal system can...... be tested up to 130oC and 51.7 MPa. Pressure, temperature and the mechanical behaviours of the pipe are measured for use in further research. The set-up is used to test the efficiency of the seal system as function of parameters such as cross sectional shapes of the gaskets, tolerances between gaskets...

Sealing devices

International Nuclear Information System (INIS)

Coulson, R.A.

1980-01-01

A sealing device for minimising the leakage of toxic or radioactive contaminated environments through a biological shield along an opening through which a flexible component moves that penetrates the shield. The sealing device comprises an outer tubular member which extends over a length not less than the maximum longitudinal movement of the component along the opening. An inner sealing block is located intermediate the length of the component by connectors and is positioned in the bore of the outer tubular member to slide in the bore and effect a seal over the entire longitudinal movement of the component. The cross-section of the device may be circular and the block may be of polytetrafluoroethylene or of nylon impregnated with molybdenum or may be metallic. A number of the sealing devices may be combined into an assembly for a plurality of adjacent longitudinally movable components, each adapted to sustain a tensile load, providing the various drives of a master-slave manipulator. (author)

Hermetically Sealed Compressor

Science.gov (United States)

Holtzapple, Mark T.

1994-01-01

Proposed hermetically sealed pump compresses fluid to pressure up to 4,000 atm (400 MPa). Pump employs linear electric motor instead of rotary motor to avoid need for leakage-prone rotary seals. In addition, linear-motor-powered pump would not require packings to seal its piston. Concept thus eliminates major cause of friction and wear. Pump is double-ended diaphragm-type compressor. All moving parts sealed within compressor housing.

Low Leakage Turbine Shaft Seals for Advanced Combined Cycle Systems.

Science.gov (United States)

1984-11-01

Study of Shaft Face Seal With Self-Acting Lift Augmentation", N71- 11579, Nov. 1970 29p. Povinelli , V.P. and McKibbin, A. H., "Development of...34, N73-24086, May 1973, 28p. Povinelli , V. P. and McKibbin, A. H., "Development of Mainshaft Seals for Advanced Air Breathing Propulsion Systems... Povinelli , V. P., "Current Seal Designs and Future Requirements for Turbine Engine Seals and Bearings", Journal of Aircraft, Vol. 12, No. 4, April 1975

Development of filters and housings for use on active plant

International Nuclear Information System (INIS)

Hackney, S.; Pratt, R.P.

1983-01-01

New designs of housings for conventional HEPA filters have been developed and are now in use. A further design is planned for future use. The main features to be developed are the engineering of double door systems to replace bag posting and other methods of filter changing which expose personnel to hazardous environments and the addition of a secondary containment to reduce the role of the gasket seal in the filtration efficiency. Also under development are circular geometry filters of HEPA standard which offer significant advantages over rectangular filters for applications requiring remote shielded change facilities. Two types of filter construction are being evaluated, conventional radial flow cartridge filters and spiral-wound, axial-flow filters. The application of circular filters for primary filter systems on active plant is in hand. A push-through change system has been developed for a new cell facility under construction at Harwell. Existing rectangular filters on a high activity cell are being replaced with clusters of small cartridge filters to overcome changing and disposal problems. A similar system but using 1700 m 3 /h filters for large volume off-gas treatment is also being studied. A remote change shielded filter installation is being developed for use in high alpha, beta, gamma extract systems. The design incorporates large cartridge filters in sealed drums with remote transfer and connection to duct work in the facility. A novel application of the use of double-lid technology removes the need for separate shut off dampers and enables the drums to be sealed for all transfer operations

Reinforced seal component

International Nuclear Information System (INIS)

Jeanson, G.M.; Odent, R.P.

1980-01-01

The invention concerns a seal component of the kind comprising a soft sheath and a flexible reinforcement housed throughout the entire length of the sheath. The invention enables O ring seals to be made capable of providing a radial seal, that is to say between two sides or flat collars of two cylindrical mechanical parts, or an axial seal, that is to say between two co-axial axisymmetrical areas. The seal so ensured is relative, but it remains adequately sufficient for many uses, for instance, to ensure the separation of two successive fixed blading compartments of axial compressors used in gas diffusion isotope concentration facilities [fr

High pressure shaft seal

International Nuclear Information System (INIS)

Martinson, A.R.; Rogers, V.D.

1980-01-01

In relation to reactor primary coolant pumps, mechanical seal assembly for a pump shaft is disclosed which features a rotating seal ring mounting system which utilizes a rigid support ring loaded through narrow annular projections in combination with centering non-sealing O-rings which effectively isolate the rotating seal ring from temperature and pressure transients while securely positioning the ring to adjacent parts. A stationary seal ring mounting configuration allows the stationary seal ring freedom of motion to follow shaft axial movement up to 3/4 of an inch and shaft tilt about the pump axis without any change in the hydraulic or pressure loading on the stationary seal ring or its carrier. (author)

Characterization of Greater-Than-Class C sealed sources. Volume 2, Sealed source characterization and future production

International Nuclear Information System (INIS)

Harris, G.; Griffel, A.

1994-09-01

Sealed sources are small, relatively high-activity radioactive sources typically encapsulated in a metallic container. The activities can range from less than 1 mCi to over 1,000 Ci. They are used in a variety of industries and are commonly available. Many of the sources will be classified as Greater-Than-Class C low-level radioactive waste (GTCC LLW) for the purpose of waste disposal. The US Department of Energy is responsible for disposing of this class of low-level radioactive waste. The characterization of a sealed source is essentially a function of the type of radiation it emits, the principal use for which it is applied, and the activity it contains. The types of radiation of most interest to the GTCC LLW Program are gamma rays and neutrons, since these are emitted by the highest activity sources. The principal uses of most importance are gamma irradiators, medical teletherapy, well logging probes, and other general neutron applications. Current annual production rates of potential Greater-Than-Class C (PGTCC) sources sold to specific licensees were estimated based on data collected from device manufacturers. These estimates were then adjusted for current trends in the industry to estimate future annual production rates. It is expected that there will be approximately 8,000 PGTCC sealed sources produced annually for specific licensees

Does the seal licensing system in Scotland have a negative impact on seal welfare?

Directory of Open Access Journals (Sweden)

Laetitia Nunny

2016-08-01

Full Text Available This study examined the licensing system that permits seal shooting in Scotland, which was established under Part 6 Conservation of Seals of the Marine (Scotland Act 2010. Four approaches were used: data were collated and analyzed from both the Scottish Government and Scottish Marine Animal Stranding Scheme; a survey was sent to current license holders and informal interviews were conducted with key stakeholder types. Between February 2011 and the end of October 2015, 1229 gray seals and 275 common seals were reported shot under license to the Scottish Government. The numbers of seals reported as shot has reduced year-on-year since the licensing system was put in place. While some license holders, notably fish farms, were using some non-lethal forms of deterrent to reduce seal-related damage, these were often used alongside seal shooting. Of the seals reported as shot to the Scottish Government, only a small percentage were also reported to the Scottish Marine Animal Stranding Scheme, despite this being a licensing requirement. Only 2.3% of the shot gray seals and 4.5% of the shot common seals were necropsied. There is evidence from these necropsies that some seals had not died instantly or had not been shot in the manner recommended by the Scottish Seal Management Code of Practice. These preliminary results show that more carcasses need to be recovered and necropsied if the welfare implications of current seal shooting practice are to be properly assessed. The current legislation does not specify closed seasons to protect breeding seals and thirty-five per cent of necropsied seals were pregnant gray seals. Seals have also been shot during their lactation periods when pups are dependent on their mothers. This raises significant welfare concerns. The re-introduction of closed seasons specific to each species of seal is recommended along with greater effort to deploy non-lethal methods. Independent assessment of the number of seals being killed

A seal analyzer for testing container integrity

International Nuclear Information System (INIS)

McDaniel, P.; Jenkins, C.

1988-01-01

This paper reports on the development of laboratory and production seal analyzer that offers a rapid, nondestructive method of assuring the seal integrity of virtually any type of single or double sealed container. The system can test a broad range of metal cans, drums and trays, membrane-lidded vessels, flexible pouches, aerosol containers, and glass or metal containers with twist-top lids that are used in the chemical/pesticide (hazardous materials/waste), beverage, food, medical and pharmaceutical industries

Circumferential shaft seal

Science.gov (United States)

Ludwig, L. P. (Inventor)

1981-01-01

A circumferential shaft seal comprising two sealing rings held to a rotating shaft by means of a surrounding elastomeric band is disclosed. The rings are segmented and are of a rigid sealing material such as carbon or a polyimide and graphite fiber composite.

Sealing arrangement for radioactive material

International Nuclear Information System (INIS)

Gray, I.L.S.; Sievwright, R.W.T.; Elliott, J.C.

1993-01-01

A sealing arrangement for hermetically sealing two mating surfaces comprises two seals arranged to lie between the surfaces. Each seal provides hermetic sealing over a respective different temperature range and lie serially along the surfaces between the regions to be isolated. A main seal integrity test arrangement is provided in the form of a port and passage. This allows for the introduction of a fluid into or the evacuation of a region between the two seals to detect a leak. The port is also provided with at least two test port seals which seal with a plug. The plug is also provided with a test port to allow the integrity of the test port seal to be tested. (UK)

Enhanced sealing project (ESP): design, construction and monitoring of a full-scale shaft seal

International Nuclear Information System (INIS)

Dixon, D.; Martino, J.; Kim, C.S.; Holowick, B.; Kwong, G.; Jonsson, E.; Palonen, E.; DeCombarieu, M.

2010-01-01

Document available in extended abstract form only. The Enhanced Sealing Project (ESP) consists of instrumenting and monitoring a full-scale shaft seal installed to permanently close the access shaft for Atomic Energy of Canada Limited's (AECL's) Underground Research Laboratory (URL) at the intersection of an ancient low dipping thrust fault. The URL was built to provide a facility where concepts for long-term management of Canada's nuclear fuel waste in a deep geological repository could be studied. Operated since the early 1980's, this facility provided much of the technical information used in developing the deep geological repository concept submitted by AECL to the Government of Canada in 1994 and continued to provide valuable technical data after that submission. In 2003, a decision was made to discontinue operation of the URL and ultimately decommission and permanently close the underground portion of this facility. As part of the Nuclear Legacy Liability Program (NLLP) being funded by Natural Resources Canada (NRCan), facilities including the URL that are no longer part of AECL's mandate or operations are being decommissioned. Included in this work is the installation of seals at the intersection of the access shaft and ventilation raise with a deep fracture zone in order to limit the potential for mixing of deeper saline and shallower less saline groundwater. The funding available from NRCan was limited to the seal installation, with no mandate to provide any more than basic hydrological monitoring of the rock mass at a considerable distance from these seals, and so the opportunity to monitor a full-scale shaft seal similar to one for a deep geological repository would have been lost. The ESP arose from the recognition by a number of organizations that the URL closure presented a unique opportunity to monitor the evolution of a full-scale repository-type shaft seal in a very well-characterized and otherwise undisturbed rock mass. As

Severe service sealing solutions

International Nuclear Information System (INIS)

Metcalfe, R.; Wensel, R.

1994-09-01

Successful sealing usually requires much more than initial leak-tightness. Friction and wear must also be acceptable, requiring a good understanding of tribology at the sealing interface. This paper describes various sealing solutions for severe service conditions. The CAN2A and CAN8 rotary face seals use tungsten carbide against carbon-graphite to achieve low leakage and long lifetime in nuclear main coolant pumps. The smaller CAN6 seal successfully uses tungsten carbide against silicon carbide in reactor water cleanup pump service. Where friction in CANDU fuelling machine rams must be essentially zero, a hydrostatic seal using two silicon carbide faces is the solution. In the NRU reactor moderator pumps, where pressure is much lower, eccentric seals that prevent boiling at the seal faces are giving excellent service. All these rotary face seals rely on supplementary elastomer seals between their parts. An integrated engineering approach to high performance sealing with O-rings is described. This is epitomized in critical Space Shuttle applications, but is increasingly being applied in CANDU plants. It includes gland design, selection and qualification of material, quality assurance, detection of defects and the effects of lubrication, surface finish, squeeze, stretch and volume constraints. In conclusion, for the severe service applications described, customized solutions have more than paid for themselves by higher reliability, lower maintenance requirements and reduced outage time. (author)

Control Design of Active Magnetic Bearings for Rotors Subjected to Destabilising Seal Forces - Theory & Experiment

DEFF Research Database (Denmark)

Lauridsen, Jonas Skjødt

. At present, there is no generally accepted method for determination of dynamic seal forces. Therefore, large uncertainties must be expected when modelling dynamic seal forces and consequently also in rotor-dynamic stability analysis. This thesis focuses on i) closed loop identification of uncertain AMB...... parameters, ii) closed loop identification of unknown stiffness and damping coefficients of a dynamicseal model and iii) the design of AMB controllers to handle dynamic seal forces. Controllers that can guarantee stability and performance in the presence of uncertainseal forces are of special interest...... the uncertaintiesin seal forces and for LPV control synthesis, to compensate for known changes in seal forces due to changes in operating conditions. A rotor dynamic test facility with a rigid rotor, two radial AMBs and one annular test seal is used for i) closed loop identification of parameters in the AMB...

Innovation to reality for improved pump seal performance

International Nuclear Information System (INIS)

Wong, W.; Eyvindson, A.; Rhodes, D.B.

2003-01-01

'Full-Text:' The nuclear industry requires reliable pump seals. Extended operating conditions for aging plants (i.e., low pressure starts, pressure and temperature transients) and increasing demands from new plants (larger sizes, higher speeds) are pushing the operating envelope for seals. This means that many seals that were previously considered adequate are now requiring increased attention and care. Operating utilities have taken different approaches to addressing their existing, or emerging, seal problems. Primary concerns include maintenance practices, seal design, and monitoring capabilities, as well as operating conditions, transients, pump and motor design. Success in this area requires ongoing dialogue among the station operators, pump manufacturers and seal designers. Regardless of the design, the basic requirement in CANDU is a reliable seal lifetime exceeding 5 years. This paper describes AECL's efforts to meet this requirement through an ongoing program of research and development in seal technology. Current work includes rigorous testing and evaluation of new seal materials and coatings to maximize seal stability and minimize friction and wear (i.e., pressure/temperature transients produce unpredictable shaft movement that can significantly alter face deflections affecting leak rates and seal stability, and sometimes cause the seal to hang-up and de-stage). Also required is a practical method for on-line monitoring of the condition of the seal, whether it is newly installed or after several years of reliable performance. This provides crucial information for inventory, maintenance and outage planning. While new concepts may look good on paper, it is only after they have been demonstrated under fully representative station operating conditions that they can truly be considered ready for field use. AECL CAN-seals lead the nuclear industry in reliability and seal life. They effectively save operators millions of dollars in outage time and person

Main-coolant-pump shaft-seal reliability investigation. Interim report

International Nuclear Information System (INIS)

Fair, C.E.; Marsi, J.A.; Greer, A.O.

1982-09-01

This report contains the results of a survey of reactor coolant pump shaft seal reliability. The survey sample is representatively large (approx. = 27% of total US commercial plant population) and includes the three industry seal suppliers (Bingham-Williamette, Byron Jackson, and Westinghouse). Operationally incurred/induced problems and seal redesign parameters are identified. Failure hypotheses in the form of fault trees have been developed to describe the failure mechanisms. Recommendations are made for seal reliability improvement

Categorization of In-use Radioactive Sealed Sources in Egypt

International Nuclear Information System (INIS)

Hasan, M.A.; Mohamed, Y.T.; El Haleim, K.A.

2006-01-01

Radioactive sealed sources have widespread applications in industry, medicine, research and education. While most sources are of relatively low activity, there are many of medium or very high activity. The mismanagement of high activity sources is responsible for most of the radiological accidents that result in loss of life or disabling injuries. Because of the variety of applications and activities of radioactive sources, a categorization system is necessary so that the controls that are applied to the sources are adequate with its radiological risk. The aim of this work is to use the international Atomic Energy Agency (IAEA) categorization system to provide a simple, logical system for grading radioactive sealed sources in Egypt. The categorizations of radioactive sealed sources are based on their potential to cause harm to human health. This study revealed that total of 1916 sources have been used in Egypt in the different applications with a total activity of 89400 Ci according to available data in October 2005. (authors)

Comparative study on two different seal surface structure for reactor pressure vessel sealing behavior

International Nuclear Information System (INIS)

Chen Jun; Xiong Guangming; Deng Xiaoyun

2014-01-01

The seal surface structure is very important to reactor pressure vessel (RPV) sealing behavior. In this paper, two 3-D RPV sealing analysis finite models have been established with different seal surface structures, in order to study the influence of two structures. The separation of RPV upper and lower flanges, bolt loads and etc. are obtained, which are used to evaluate the sealing behavior of the RPV. Meanwhile, the comparative analysis of safety margin of two seal surface structural had been done, which provides the theoretical basis for RPV seal structure design optimization. (authors)

Design and Calibration of a Full Scale Active Magnetic Bearing Based Test Facility for Investigating Rotordynamic Properties of Turbomachinery Seals in Multiphase Flow

DEFF Research Database (Denmark)

Voigt, Andreas Jauernik; Mandrup-Poulsen, Christian; Nielsen, Kenny Krogh

2016-01-01

of the subsea installed rotating machinery. It is well known that careful design of turbomachinery seals, such as interstage and balance piston seals, is pivotal for the performance of pumps and compressors. Consequently, the ability to predict the complex interaction between fluid dynamics and rotordynamics...... University of Denmark and Lloyd's Register Consulting are currently establishing a purpose built state of the art multiphase seal test facility, which is divided into three modules. Module I consists of a full scale Active Magnetic Bearing (AMB) based rotor dynamic test bench. The internally designed custom...... AMBs are equipped with an embedded Hall sensor system enabling high precision non-contact seal force quantification. Module II is a fully automatised calibration facility for the Hall sensor based force quantification system. Module III consists of the test seal housing assembly. This paper provides...

Urban gray vs. urban green vs. soil protection — Development of a systemic solution to soil sealing management on the example of Germany

International Nuclear Information System (INIS)

Artmann, Martina

2016-01-01

Managing urban soil sealing is a difficult venture due to its spatial heterogeneity and embedding in a socio-ecological system. A systemic solution is needed to tackle its spatial, ecological and social sub-systems. This study develops a guideline for urban actors to find a systemic solution to soil sealing management based on two case studies in Germany: Munich and Leipzig. Legal-planning, informal-planning, economic-fiscal, co-operative and informational responses were evaluated by indicators to proof which strategy considers the spatial complexity of urban soil sealing (systemic spatial efficiency) and, while considering spatial complexity, to assess what the key management areas for action are to reduce the ecological impacts by urban soil sealing (ecological impact efficiency) and to support an efficient implementation by urban actors (social implementation efficiency). Results suggest framing the systemic solution to soil sealing management through a cross-scale, legal-planning development strategy embedded in higher European policies. Within the socio-ecological system, the key management area for action should focus on the protection of green infrastructure being of high value for actors from the European to local scales. Further efforts are necessary to establish a systemic monitoring concept to optimize socio-ecological benefits and avoid trade-offs such as between urban infill development and urban green protection. This place-based study can be regarded as a stepping stone on how to develop systemic strategies by considering different spatial sub-targets and socio-ecological systems. - Highlights: • Urban soil sealing management is spatially complex. • The legal-planning strategy supports a systemic sealing management. • Urban green infrastructure protection should be in the management focus. • Soil protection requires policies from higher levels of government. • A systemic urban soil sealing monitoring concept is needed.

Urban gray vs. urban green vs. soil protection — Development of a systemic solution to soil sealing management on the example of Germany

Energy Technology Data Exchange (ETDEWEB)

Artmann, Martina, E-mail: m.artmann@ioer.de

2016-07-15

Managing urban soil sealing is a difficult venture due to its spatial heterogeneity and embedding in a socio-ecological system. A systemic solution is needed to tackle its spatial, ecological and social sub-systems. This study develops a guideline for urban actors to find a systemic solution to soil sealing management based on two case studies in Germany: Munich and Leipzig. Legal-planning, informal-planning, economic-fiscal, co-operative and informational responses were evaluated by indicators to proof which strategy considers the spatial complexity of urban soil sealing (systemic spatial efficiency) and, while considering spatial complexity, to assess what the key management areas for action are to reduce the ecological impacts by urban soil sealing (ecological impact efficiency) and to support an efficient implementation by urban actors (social implementation efficiency). Results suggest framing the systemic solution to soil sealing management through a cross-scale, legal-planning development strategy embedded in higher European policies. Within the socio-ecological system, the key management area for action should focus on the protection of green infrastructure being of high value for actors from the European to local scales. Further efforts are necessary to establish a systemic monitoring concept to optimize socio-ecological benefits and avoid trade-offs such as between urban infill development and urban green protection. This place-based study can be regarded as a stepping stone on how to develop systemic strategies by considering different spatial sub-targets and socio-ecological systems. - Highlights: • Urban soil sealing management is spatially complex. • The legal-planning strategy supports a systemic sealing management. • Urban green infrastructure protection should be in the management focus. • Soil protection requires policies from higher levels of government. • A systemic urban soil sealing monitoring concept is needed.

Seals in motion

NARCIS (Netherlands)

Brasseur, Sophie Marie Jacqueline Michelle

2017-01-01

The harbour seal Phoca vitulina and the grey seal Halichoerus grypus have been inhabitants of the Wadden Sea since millennia. Prehistoric findings indicate the presence of both species around 5000 BC. This changed dramatically in the mid Middle-Ages as around 1500 AC, the grey seal disappeared from

The development of an auto-sealing system using an electrically shrinkable tube under a low-pressure condition

Energy Technology Data Exchange (ETDEWEB)

Okano, Yoshihiro; Kitagawa, Takao [NKK Corp, Tsu, Mie (Japan); Shoji, Norio [NKK Corp., Yokohama (Japan); Namioka, Toshiyuki [Nippon Kokan Koji Corp., Yokohama (Japan). Research and Development Dept.; Komura, Minoru [Nitto Denko Corp., Fukaya, Saitama (Japan)

1997-04-01

This article describes the development of a system to create high quality, automatic sealing of field joints of polyethylene coated pipelines. The system uses a combination of an electrically heated shrinkable tube and a low-pressure chamber. The self-heating shrinkable tube includes electric heater wires that heat when connected to electricity. A method was developed to eliminate air trapped between the tube and the steel pipe by shrinking the tube under a low-pressure condition. The low-pressure condition was automatic and easily attained by using a vacuum chamber. It was verified that the system produced high quality sealing of the field joints.

Study of Seal Glass for Solid Oxide Fuel/Electrolyzer Cells

OpenAIRE

Mahapatra, Manoj Kumar

2009-01-01

Seal glass is essential and plays a crucial role in solid oxide fuel/electrolyzer cell performance and durability. A seal glass should have a combination of thermal, chemical, mechanical, and electrical properties in order to seal different cell components and stacks and prevent gas leakage. All the desired properties can simultaneously be obtained in a seal glass by suitable compositional design. In this dissertation, SrO-La₂O₃-A₂O₃-B₂O₃3-SiO₂ based seal glasses have been developed and compo...

Development of Induction Brazing System for Sealing Instrumentation Feed through Part of Nuclear Fuel Test Rig

Energy Technology Data Exchange (ETDEWEB)

Hong, Jintae; Kim, Kahye; Heo, Sungho; Ahn, Sungho; Joung, Changyoung; Son, Kwangjae; Jung, Yangil [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2013-12-15

To test the performance of nuclear fuels, coolant needs to be circulated through the test rig installed in the test loop. Because the pressure and temperature of the coolant is 15.5 MPa and 300 .deg. C respectively, coolant sealing is one of the most important processes in fabricating a nuclear fuel test rig. In particular, 15 instrumentation cables installed in a test rig pass through the pressure boundary, and brazing is generally applied as a sealing method. In this study, an induction brazing system has been developed using a high frequency induction heater including a vacuum chamber. For application in the nuclear field, BNi2 should be used as a paste, and optimal process variables for Ni brazing have been found by several case studies. The performance and soundness of the brazed components has been verified by a tensile test, cross section test, and sealing performance test.

Study of the static airtightness mechanisms of metal seals

International Nuclear Information System (INIS)

Tlili, A.

2013-01-01

The thesis aims to better understand the sealing mechanisms in contact at the interface between a metal gasket and clamps. The proposed approach is based on the development of a numerical model of the clamping seal by incorporating the laws' behavior of materials that will be determined by micro instrumented indentation testing. This model is particularly interested in identifying ways of providing the fluid leak to be sealed and to determine leakage rates resulting from the identified paths, as well as the evolution of the conductance of the interface over time. Particular attention will be paid to the roughness of the surfaces, changing leak paths at different levels depending on the tightening of the seal and gas flow rates in the different types of defects. The study was conducted in Pierrelatte's Sealing laboratory that develops metal seals for the aerospace, nuclear and scientific research. The thesis focuses on real surfaces and was supplemented by measurements of helium leaks using a press which applies different loads at different gas pressures and different roughness. (author) [fr

Lesson Learned from Conditioning of Disused Sealed Radioactive Sources (DSRS) in Malaysia

International Nuclear Information System (INIS)

Nik Marzukee Nik Ibrahim; Mohd Abdul Wahab Yusof; Norasalwa Zakaria

2016-01-01

This paper presents the conditioning of disused sealed radioactive source (DSRS) in Malaysia. In Malaysia, sealed radioactive sources (SRS) are widely used in Malaysia especially in industry, medicine and research. Once SRS are no longer in use, they are declared disused and managed as radioactive waste. In order to reduce the risk associated with disused sealed radioactive sources (DSRS), the first priority would be to bring them under appropriate controls. This paper describes the experience developed and activities performed by Nuclear Malaysia throughout the period in conditioning of DSRS as well as future programme to further enhancing the infrastructure. Collaborative efforts with the various relevant groups such as Loji and Prototaip Development Centre (PDC) and Industrial Technology Division (BTI) provide an effective avenue in ensuring successful implementation of the programme. Currently, until August 2015, Malaysia has in possession about 12,154 unit of DSRS categories 3-5 and 4 units of DSRS category 2 sources which being stored at the interim storage facility Nuclear Malaysia. A national activity was implemented for the on-the-job training of personnel tasked with the conditioning of DSRS, at the Waste Technology Development Centre (WasTeC) facilities. This is part of -cradle-to-grave- control of radioactive sources to protect the workers and public from the hazards of ionizing radiation. (author)

Seals Research at AlliedSignal

Science.gov (United States)

Ullah, M. Rifat

1996-01-01

A consortium has been formed to address seal problems in the Aerospace sector of Allied Signal, Inc. The consortium is represented by makers of Propulsion Engines, Auxiliary Power Units, Gas Turbine Starters, etc. The goal is to improve Face Seal reliability, since Face Seals have become reliability drivers in many of our product lines. Several research programs are being implemented simultaneously this year. They include: Face Seal Modeling and Analysis Methodology; Oil Cooling of Seals; Seal Tracking Dynamics; Coking Formation & Prevention; and Seal Reliability Methods.

Radioactive sealed sources production process for industrial radiography

International Nuclear Information System (INIS)

Santos, Paulo de S.; Ngunga, Daniel M.G.; Camara, Julio R.; Vasquez, Pablo A.S.

2017-01-01

providing products and services to the private and governmental Brazilian users of industrial radiography and nucleonic control systems. Radioactive sealed sources are commonly used in nondestructive tests as radiography to make inspections and verify the internal structure and integrity of materials and in nucleonic gauges to control level, density, viscosity, etc. in on-line industrial processes. One of the most important activities carried out by this laboratory is related to the inspection of source projectors devices used in industrial radiography and its constituent parts as well as remote handle control assembly drive cable and guide tube systems. The laboratory also provide for the users iridium-192, cobalt-60 and selenium-75 sealed sources and performs quality control tests replacing spent or contaminated radiative sources. All discard of radioactive source is treated as radioactive waste. Additionally, administrative and commercial processes and protocols for exportation and transport of radioactive material are developed by specialized departments. In this work are presented the mean processes and procedures used by the Sealed Source Production Laboratory such as the arrival of the radioactive material to the laboratory and the source projectors, mechanical inspections, source loading, source leaking tests, etc. (author)

Radioactive sealed sources production process for industrial radiography

Energy Technology Data Exchange (ETDEWEB)

Santos, Paulo de S.; Ngunga, Daniel M.G.; Camara, Julio R.; Vasquez, Pablo A.S., E-mail: psantos@ipen.br, E-mail: hobeddaniel@gmail.com, E-mail: jrcamara@ipen.br, E-mail: pavsalva@ipen.br [Instituto de Pesquisas Energética s e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

2017-07-01

providing products and services to the private and governmental Brazilian users of industrial radiography and nucleonic control systems. Radioactive sealed sources are commonly used in nondestructive tests as radiography to make inspections and verify the internal structure and integrity of materials and in nucleonic gauges to control level, density, viscosity, etc. in on-line industrial processes. One of the most important activities carried out by this laboratory is related to the inspection of source projectors devices used in industrial radiography and its constituent parts as well as remote handle control assembly drive cable and guide tube systems. The laboratory also provide for the users iridium-192, cobalt-60 and selenium-75 sealed sources and performs quality control tests replacing spent or contaminated radiative sources. All discard of radioactive source is treated as radioactive waste. Additionally, administrative and commercial processes and protocols for exportation and transport of radioactive material are developed by specialized departments. In this work are presented the mean processes and procedures used by the Sealed Source Production Laboratory such as the arrival of the radioactive material to the laboratory and the source projectors, mechanical inspections, source loading, source leaking tests, etc. (author)

Compliant Glass Seals for SOFC Stacks

Energy Technology Data Exchange (ETDEWEB)

Chou, Yeong -Shyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Choi, Jung-Pyung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Wei [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stephens, Elizabeth V. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Koeppel, Brian J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stevenson, Jeffry W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lara-Curzio, Edgar [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2014-04-30

This report summarizes results from experimental and modeling studies performed by participants in the Solid-State Energy Conversion Alliance (SECA) Core Technology Program, which indicate that compliant glass-based seals offer a number of potential advantages over conventional seals based on de-vitrifying glasses, including reduced stresses during stack operation and thermal cycling, and the ability to heal micro-damage induced during thermal cycling. The properties and composition of glasses developed and/or investigated in these studies are reported, along with results from long-term (up to 5,800h) evaluations of seals based on a compliant glass containing ceramic particles or ceramic fibers.

Brush seal performance measurement system

OpenAIRE

Aksoy, Serdar; Akşit, Mahmut Faruk; Aksit, Mahmut Faruk; Duran, Ertuğrul Tolga; Duran, Ertugrul Tolga

2009-01-01

Brush seals are rapidly replacing conventional labyrinth seals in turbomachinery applications. Upon pressure application, seal stiffness increases drastically due to frictional bristle interlocking. Operating stiffness is critical to determine seal wear life. Typically, seal stiffness is measured by pressing a curved shoe to brush bore. The static-unpressurized measurement is extrapolated to pressurized and high speed operating conditions. This work presents a seal stiffness measurement syste...

Seals

International Nuclear Information System (INIS)

Welsher, R.A.G.

1982-01-01

An aperture through a biological shield is sealed by a flexible sheath having a beading at one end located on an annular member slidable in the aperture such that the beading bears in sealing engagement against the sides of the aperture. The annular member is retained by a retractable latch and can be rejected by pushing it out of the aperture using a replacement annular member with a replacement sheath thereon to butt against the annular member to be rejected. The replacement annular member may be mounted on a tubular device having an outer co-axial member for operating the latch when the replacement annular member butts against the annular member to be rejected. Applications include effecting a seal between a remote handling equipment and a wall through which the equipment extends. (author)

Dynamics of face seals for high speed turbomachinery

Science.gov (United States)

Leefe, Simon

1993-10-01

Face seals in rocket engine fuel and oxidizer turbopumps have been the subject of intense investigation for over 25 years. While advances have been made in the understanding of thin film lubrication between seal faces, valuable data has been produced on the friction and wear of material pairs in cryogenic environments; pioneering work has been done on the effect of lubricant phase change in seals, and many improvements have been made in mechanical seal design. Relatively superficial attention has been given to the vibrational dynamics of face seals in high-speed turbomachinery. BHR Group Ltd. (formerly BHRA) has recently completed the first stage of a study, commissioned by the European Space Agency, to investigate this area. This has involved the development of a two-dimensional adiabatic, turbulent lubrication model for thick gas film applications, the production of an integrated mathematical model of gas seal vibrational dynamics for thin film applications, implementation in software, the undertaking of an experimental program to validate software against variations in operating conditions and design variables, and suggestions for improved seal design.

Electronic seal

International Nuclear Information System (INIS)

Musyck, E.

1981-01-01

An electronic seal is presented for a volume such as container for fissile materials. The seal encloses a lock for barring the space as well as a device for the detection and the recording of the intervention of the lock. (AF)

The development for C-band whole sealed vacuum accelerating tuber

International Nuclear Information System (INIS)

Zhou Wenzhen; Zhang Xiangyang; Ding Shulin; Hu Jinquan; Yang Zhenyuan

1999-01-01

S-Band standing wave electron linacs have got wide-ranging application for industry nondestructive testing and formed varied kinds of products. X-band electron linac for NDT has been developed by Schonberg Company USA in 1985. Because of bigger structure of S-band linac and difficult machining of X-Band linac, an C-band portable linac for NDT has been developed in CIAE at present, a whole sealed vacuum accelerating tuber will be given here. It consists of 4 cavities, the phase velocity of the first two cavities is 0.5 and 0.9, respectively, and that of the second two cavities is 1. The high power testing proved that the design of the accelerating tuber is good for 1.5 MeV electron linac for NDT

Pressure vessels and methods of sealing leaky tubes disposed in pressure vessels

International Nuclear Information System (INIS)

Larson, G.C.

1980-01-01

This invention relates to pressure vessels and to methods of sealing leaky tubes in them and is especially applicable to pressure vessels in the form of sheet-and-tube type heat exchangers constructed with a large number of relatively small diameter tubes grouped in a bundle. To seal off a leaky tube in such a heat exchanger an explosive activated plug in the form of a hollow metal body is used, inserted at each end of the tube to be sealed. Using the arrangement of pressure vessel and associated tube sheets and the explosive activated plug method of sealing a leaky tube as described in this invention it is claimed that distortion of the adjacent tubes and the tube sheets is reduced when the explosive activated plugs are detonated. (U.K.)

ASTUS system for verifying the transport seal TITUS 1

International Nuclear Information System (INIS)

Barillaux; Monteil, D.; Destain, G.D.

1991-01-01

ASTUS, a system for acquisition and processing ultrasonic signatures of TITUS 1 seals has been developed. TITUS seals are used to verify the integrity of the fissile material's container sealing after transport. An autonomous portable reading case permit to take seals signatures at the starting point and to transmit these reference signatures to a central safeguards computer by phonic modem. Then, at the terminal point with a similar reading case, an authority takes again the signature of seals and immediately transmit these signatures to the central safeguards computer. The central computer processes the data in real time by autocorrelation and return its verdict to the terminal point

Blood metal levels and metal-influenced immune functions of harbour seals in captivity

International Nuclear Information System (INIS)

Kakuschke, Antje; Valentine-Thon, Elizabeth; Griesel, Simone; Rosenberger, Tanja; Mundry, Roger; Siebert, Ursula; Prange, Andreas

2008-01-01

Immunological blood parameters and the effects of environmental pollutants on the immune system are important to assess the health status of seals. Animals living permanently in seal centres are useful for development and validation of diagnostic tools for free-ranging animals. In this study, parameters of cellular immunity as well as metal concentrations in blood and metal influence on cell proliferation of seven seals from a seal centre were investigated repeatedly using multi-element analysis and a lymphocyte proliferation assay. The metal concentrations, except for tin and chromium, were in general comparable to those of free-ranging animals of the North Sea. The unstimulated and mitogen-stimulated lymphocyte proliferation showed strong intra- and inter-individual variability, which reflected variability in activation of the immune status. Furthermore, both immunosuppressive and stimulative influences of metals on lymphocytes were found. Summarising, the methods used in this investigation provided useful information on these animals, and their application to free-ranging animals can be recommended

Safety considerations in the disposal of disused sealed radioactive sources in borehole facilities

CERN Document Server

International Atomic Energ Agency. Vienna

2003-01-01

Sealed radioactive sources are used in medicine, industry and research for a wide range of purposes. They can contain different radionuclides in greatly varying amounts. At the end of their useful lives, they are termed 'disused sources' but their activity levels can still be quite high. They are, for all practical purposes, another type of radioactive waste that needs to be disposed of safely. Disused sealed radioactive sources can represent a significant hazard to people if not managed properly. Many countries have no special facilities for the management or disposal of radioactive waste, as they have no nuclear power programmes requiring such facilities. Even in countries with developed nuclear programmes, disused sealed sources present problems as they often fall outside the common categories of radioactive waste for which disposal options have been identified. As a result, many disused sealed sources are kept in storage. Depending on the nature of the storage arrangements, this situation may represent a ...

Blood metal levels and metal-influenced immune functions of harbour seals in captivity

Energy Technology Data Exchange (ETDEWEB)

Kakuschke, Antje [GKSS Research Centre, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany)], E-mail: antje.kakuschke@gkss.de; Valentine-Thon, Elizabeth [Department of Immunology, Laboratory Center Bremen, Friedrich-Karl-Strasse 22, 28205 Bremen (Germany); Griesel, Simone [GKSS Research Centre, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany); Rosenberger, Tanja [Seal Centre Friedrichskoog e.V., 25718 Friedrichskoog (Germany); Mundry, Roger [Research and Technology Centre Westcoast (FTZ), University of Kiel, Hafentoern 1, 25761 Buesum (Germany); Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig (Germany); Siebert, Ursula [Research and Technology Centre Westcoast (FTZ), University of Kiel, Hafentoern 1, 25761 Buesum (Germany); Prange, Andreas [GKSS Research Centre, Institute for Coastal Research, Max-Planck-Strasse 1, 21502 Geesthacht (Germany)

2008-04-15

Immunological blood parameters and the effects of environmental pollutants on the immune system are important to assess the health status of seals. Animals living permanently in seal centres are useful for development and validation of diagnostic tools for free-ranging animals. In this study, parameters of cellular immunity as well as metal concentrations in blood and metal influence on cell proliferation of seven seals from a seal centre were investigated repeatedly using multi-element analysis and a lymphocyte proliferation assay. The metal concentrations, except for tin and chromium, were in general comparable to those of free-ranging animals of the North Sea. The unstimulated and mitogen-stimulated lymphocyte proliferation showed strong intra- and inter-individual variability, which reflected variability in activation of the immune status. Furthermore, both immunosuppressive and stimulative influences of metals on lymphocytes were found. Summarising, the methods used in this investigation provided useful information on these animals, and their application to free-ranging animals can be recommended.

30 CFR 816.13 - Casing and sealing of drilled holes: General requirements.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Casing and sealing of drilled holes: General...-SURFACE MINING ACTIVITIES § 816.13 Casing and sealing of drilled holes: General requirements. Each exploration hole, other drill or borehole, well, or other exposed underground opening shall be cased, sealed...

Prospective randomized trial compares suction versus water seal for air leaks.

Science.gov (United States)

Cerfolio, R J; Bass, C; Katholi, C R

2001-05-01

Surgeons treat air leaks differently. Our goal was to evaluate whether it is better to place chest tubes on suction or water seal for stopping air leaks after pulmonary surgery. A second goal was to evaluate a new classification system for air leaks that we developed. Patients were prospectively randomized before surgery to receive suction or water seal to their chest tubes on postoperative day (POD) #2. Air leaks were described and quantified daily by a classification system and a leak meter. The air-leak meter scored leaks from 1 (least) to 7 (greatest). The group randomized to water seal stayed on water seal unless a pneumothorax developed. On POD #2, 33 of 140 patients had an air leak. Eighteen patients had been preoperatively randomized to water seal and 15 to suction. Air leaks resolved in 12 (67%) of the water seal patients by the morning of POD #3. All 6 patients whose air leak did not stop had a leak that was 4/7 or greater (p leak meter. Of the 15 patients randomized to suction, only 1 patient's air leak (7%) resolved by the morning of POD #3. The randomization aspect of the trial was ended and statistical analysis showed water seal was superior (p = 0.001). The remaining 14 patients were then placed to water seal and by the morning of POD #4, 13 patients' leaks had stopped. Of the 32 total patients placed to seal, 7 (22%) developed a pneumothorax and 6 of these 7 patients had leaks that were 4/7 or greater (p = 0.001). Placing chest tubes on water seal seems superior to wall suction for stopping air leaks after pulmonary resection. However, water seal does not stop expiratory leaks that are 4/7 or greater. Pneumothorax may occur when chest tubes are placed on seal with leaks this large.

Sure confinement of spent sealed sources

International Nuclear Information System (INIS)

Lizcano, D.

2013-10-01

The industrial and technological development of the last decades produced and increment in the radiations application in different human activities. One of the main effects has been the production of radioactive wastes of all the levels. In Mexico, several stages of the waste management of low and intermediate level have not been completely resolved, as the case of the treatment and the final storage. In this work the confinement of spent sealed sources is described, maintaining as main objective the security of these sources and the protection to the workers and the people. (author)

A two-stage ceramic tile grout sealing process using a high power diode laser—Grout development and materials characteristics

Science.gov (United States)

Lawrence, J.; Li, L.; Spencer, J. T.

1998-04-01

Work has been conducted using a 60 Wcw high power diode laser (HPDL) in order to determine the feasibility and characteristics of sealing the void between adjoining ceramic tiles with a specially developed grout material having an impermeable enamel surface glaze. A two-stage process has been developed using a new grout material which consists of two distinct components: an amalgamated compound substrate and a glazed enamel surface; the amalgamated compound seal providing a tough, heat resistant bulk substrate, whilst the enamel provides an impervious surface. HPDL processing has resulted in crack free seals produced in normal atmospheric conditions. The basic process phenomena are investigated and the laser effects in terms of seal morphology, composition and microstructure are presented. Also, the resultant heat affects are analysed and described, as well as the effects of the shield gases, O 2 and Ar, during laser processing. Tiles were successfully sealed with power densities as low as 500 W/cm 2 and at rates up to 600 mm/min. Contact angle measurements revealed that due to the wettability characteristics of the amalgamated oxide compound grout (AOCG), laser surface treatment was necessary in order to alter the surface from a polycrystalline to a semi-amorphous structure, thus allowing the enamel to adhere. Bonding of the enamel to the AOCG and the ceramic tiles was identified as being principally due to van der Waals forces, and on a very small scale, some of the base AOCG material dissolving into the glaze.

LM2500+ Brush Seal Case Study

Science.gov (United States)

Haaser, Fred G.

2006-01-01

The LM2500+ industrial aeroderivative gas turbine, a 25% enhanced power derivative of the LM2500 gas turbine, recently completed its development test program during the period 5/96 - 10/96. Early in the engine program a Quality Function Deployment (QFD) process was used to determine customer needs for this project.The feedback obtained from the QFD process showed without doubt that gas turbine customers now emphasize product reliability and availability at the top of their needs. One area of development on the LM2500+ was to investigate the use of a brush seal as a means to reduce undesirable turbine cooling leakages within the turbine mid frame in order to enhance part life. This presentation presents a case study on the factors that went into evaluating a brush seal during engine test, test results, and the ultimate decision not to implement the brush seal for cost and other reasons.

Design and analysis of seals for extended service life

Science.gov (United States)

Bower, Mark V.

1992-01-01

Space Station Freedom is being developed for a service life of up to thirty years. As a consequence, the design requirements for the seals to be used are unprecedented. Full scale testing to assure the selected seals can satisfy the design requirements are not feasible. As an alternative, a sub-scale test program has been developed by MSFC to calibrate the analysis tools to be used to certify the proposed design. This research has been conducted in support of the MSFC Integrated Seal Test Program. The ultimate objective of this research is to correlate analysis and test results to qualify the analytical tools, which in turn, are to be used to qualify the flight hardware. This research is totally focused on O-rings that are compressed by perpendicular clamping forces. In this type of seal the O-ring is clamped between the sealing surfaces by loads perpendicular to the circular cross section.

Development of hard-seal gate valve and fast shutter for JT-60 neutral beam injectors

International Nuclear Information System (INIS)

Kuribayashi, S.; Minami, M.; Matsuoka, T.; Takeshita, K.; Morita, H.; Kuriyama, M.; Matsuda, S.; Shirakata, H.

1983-01-01

A 600 mm hard-seal valve and a fast shutter for the JT-60 Neutral Beam Injector were developed. The 600 mm hard-seal gate valve was fabricated and tested for 500 cycles at various temperatures of up to 250 0 C. In consequence, requirements of the endurance and vacuum tightness were satisfied. Major components of the fast shutter, i.e., swing action bellows and a high-speed pneumatic cylinder, were tested for 30,000 cycles, and their reliability was confirmed. Then the fast shutter was fabricated and tested. The test result indicated that the fast shutter fully satisfied the requirements of the molecular gas flow conductance and opening/closing speed. (author)

Shaft seal assembly and method

Science.gov (United States)

Keba, John E. (Inventor)

2007-01-01

A pressure-actuated shaft seal assembly and associated method for controlling the flow of fluid adjacent a rotatable shaft are provided. The seal assembly includes one or more seal members that can be adjusted between open and closed positions, for example, according to the rotational speed of the shaft. For example, the seal member can be configured to be adjusted according to a radial pressure differential in a fluid that varies with the rotational speed of the shaft. In addition, in the closed position, each seal member can contact a rotatable member connected to the shaft to form a seal with the rotatable member and prevent fluid from flowing through the assembly. Thus, the seal can be closed at low speeds of operation and opened at high speeds of operation, thereby reducing the heat and wear in the seal assembly while maintaining a sufficient seal during all speeds of operation.

Operating reliability of the shaft seal system of ANDRITZ RCP

International Nuclear Information System (INIS)

Grancy, Werner; Zehentner, Martin

2002-01-01

The next generation of nuclear power stations will have to fulfil new expectations in terms of safety, operating behaviour and costs. This applies also and especially to reactor coolant pumps for the primary circuit of pressurized water reactor type nuclear power plants (RCP). For 4 decades, ANDRITZ AG has developed and built RCPs and has attached great importance to the design of the complete pump rotor and of its essential surrounding elements, such as e. g. the shaft seal. Many questions concerning design and configuration of the shaft seal system cannot be answered purely theoretically, or they can only be answered partly. Therefore, comprehensive development work and testing was necessary to increase the operating reliability of the seal. Apart from all relevant questions connected with design and functioning of the pump there is one question of top priority: the operating reliability of the shaft seal system. Therefore it is intended to describe the current status of design and development of ANDRITZ RCP for future Korean NPPs, to present the most important design features and to give an introduction concerning experiences for a 3-stage-hydrodynamic seal as well as for a 2-stage-hydrodynamic seal

Verification on reliability of diaphragm seal

International Nuclear Information System (INIS)

Ide, Hiroshi; Sakuta, Yoshiyuki; Hanawa, Yoshio; Tsuji, Tomoyuki; Tsuboi, Kazuaki; Nagao, Yoshiharu; Miyazawa, Masataka

2009-06-01

The main body of the JMTR is composed of reactor pressure vessel, core and reactor pool. At the bottom of the reactor pool, the Diaphragm-seal (2.6m outer diameter, 2m inner diameter, thickness 1.5mm) of the JMTR made of stainless steel is installed to prevent the water leak of the reactor pool and to absorb the expansion of the reactor pressure vessel due to pressure and temperature changes. In the long-term maintenance plans drawn up in 2004, it is required that the visual inspection for the diaphragm-seal should be carried out in 2007 and that the inspection should be carried out every around five-year. Therefore, prior to the refurbishment of the JMTR, the inspection device which is a deposition-collection apparatus with underwater-camera was developed, and the visual inspection was carried out to confirm the soundness of the diaphragm-seal. As a result, harmful flaws and/or corrosions were not inspected in the visual inspection, and the soundness of the diaphragm seal was confirmed. In future, the long-term integrity of the diaphragm-seal will could be achieved by conducting the periodic inspection. (author)

Rotary shaft seal

International Nuclear Information System (INIS)

Langebrake, C.O.

1984-01-01

The invention is a novel rotary shaft seal assembly which provides positive-contact sealing when the shaft is not rotated and which operates with its sealing surfaces separated by a film of compressed ambient gas whose width is independent of the speed of shaft rotation. In a preferred embodiment, the assembly includes a disc affixed to the shaft for rotation therewith. Axially movable, non-rotatable plates respectively supported by sealing bellows are positioned on either side of the disc to be in sealing engagement therewith. Each plate carries piezoelectric transducer elements which are electrically energized at startup to produce films of compressed ambient gas between the confronting surfaces of the plates and the disc. Following shutdown of the shaft, the transducer elements are de-energized. A control circuit responds to incipient rubbing between the plate and either disc by altering the electrical input to the transducer elements to eliminate rubbing

Seal containment system

International Nuclear Information System (INIS)

Kugler, R.W.; Gerkey, K.S.; Kasner, W.H.

1978-01-01

An automated system for transporting nuclear fuel elements between fuel element assembly stations without contaminating the area outside the sealed assembly stations is described. The system comprises a plurality of assembly stations connected together by an elongated horizontal sealing mechanism and an automatic transport mechanism for transporting a nuclear fuel element in a horizontal attitude between the assembly stations while the open end of the fuel element extends through the sealing mechanism into the assembly station enclosure. The sealing mechanism allows the fuel element to be advanced by the transport mechanism while limiting the escape of radioactive particles from within the assembly station enclosure. 4 claims, 6 figures

SEAFP and SEAL: safety and environmental aspects

International Nuclear Information System (INIS)

Gulden, W.; Raeder, J.; Cook, I.

2000-01-01

The Safety and Environmental Assessment of Fusion Power (SEAFP) programme undertaken in the period 1992-1995 formed part of the ongoing effort in the European Fusion Programme to consider the safety and environmental aspects of fusion power. The assessment started with the development of a tokamak fusion power plant model of 3000 MW of fusion power. The analyses of safety included detailed consideration of effluents from normal operation, occupational doses, accidents (concentrating on the worst possible), and waste management. SEAFP was also the starting point for the Safety and Environmental Assessment of Fusion Power -- Long Term Programme (SEAL) initiated within the European Fusion Programme in 1995. SEAL aims at broadening the scope and elaborating selected aspects in more detail. SEAFP and SEAL confirmed the favourable safety and environmental characteristics of fusion power. They also confirmed the need to support these characteristics by dedicated materials development and safety-related design decisions. Recently, a new study on fusion safety (SEAFP-2) has been launched, defined for the time period 1997-1998, using SEAFP and SEAL findings as starting points

Core disruptive accident margin seal

International Nuclear Information System (INIS)

Golden, M.P.

1979-01-01

An apparatus for sealing the annulus defined within a substantially cylindrical rotatable riser assembly and plug combination of a nuclear reactor closure head is described. The apparatus comprises an inflatable sealing mechanism disposed in one portion of the riser assembly near the annulus such that upon inflation the sealing mechanism is radially actuated against the other portion of the riser assembly thereby sealing the annulus. The apparatus further comprises a connecting mechanism which places one end of the sealing mechanism in fluid communication with the reactor cover gas so that overpressurization of the reactor cover gas will increase the radial actuation of the sealing mechanism thus enhancing sealing of the annulus

Mechanical Behaviour of Glassy Composite Seals for IT-SOFC Application

DEFF Research Database (Denmark)

Nielsen, Karsten Agersted; Solvang, Mette; Nielsen, Sofie Birkedal Lund

2007-01-01

Glass-based sealants have been developed with emphasis on filler material and surface treatment of the sealing components in order to optimise their mechanical and functional behaviour during the initial sealing process as well as during thermal cycling of the SOFC-stack after exposure to operating...... conditions. The bonding strength and microstructure of the interfaces between composite seals and interconnect materials were investigated as a function of surface treatment of the sealing surfaces, glass matrix composition, sealing pressure and temperature. The initial sealing performance and resistance...... to thermal cycling were then investigated on selected combinations of materials after ageing. Strongest bonding between sodium aluminosilicate glass composite and steel surfaces was obtained for sealing at 850°C. For the strongest interface, having shear strength of 2.35 MPa, rupture occurred in the glass...

Magnetic nanofluids and magnetic composite fluids in rotating seal systems

International Nuclear Information System (INIS)

Borbath, T; Borbath, I; Boros, T; Bica, D; Vekas, L; Potencz, I

2010-01-01

Recent results are presented concerning the development of magnetofluidic leakage-free rotating seals for vacuum and high pressure gases, evidencing significant advantages compared to mechanical seals. The micro-pilot scale production of various types of magnetizable sealing fluids is shortly reviewed, in particular the main steps of the chemical synthesis of magnetic nanofluids and magnetic composite fluids with light hydrocarbon, mineral oil and synthetic oil carrier liquids. The behavior of different types of magnetizable fluids in the rotating sealing systems is analyzed. Design concepts, some constructive details and testing procedures of magnetofluidic rotating seals are presented such as the testing equipment. The main characteristics of several magnetofluidic sealing systems and their applications will be presented: vacuum deposition systems and liquefied gas pumps applications, mechanical and magnetic nanofluid combined seals, gas valves up to 40 bar equipped by rotating seal with magnetic nanofluids and magnetic composite fluids.

Improved circumferential shaft seal

Science.gov (United States)

Ludwig, L. P.; Strom, T. N.

1974-01-01

Comparative tests of modified and unmodified carbon ring seals showed that addition of helical grooves to conventional segmented carbon ring seals reduced leakage significantly. Modified seal was insensitive to shaft runout and to flooding by lubricant.

Seals for sealing a pressure vessel such as a nuclear reactor vessel or the like

International Nuclear Information System (INIS)

Bruns, H.J.; Huelsermann, K.H.

1975-01-01

A description is given of seals for sealing a pressure vessel such as a nuclear reactor vessel, steam boiler vessel, or any other vessel which is desirably sealed against pressure of the type including a housing and a housing closure that present opposed vertical sealing surfaces which define the sides of a channel. The seals of the present invention comprise at least one sealing member disposed in the channel, having at least one stop face, a base portion and two shank portions extending from the base portion to form a groove-like recess. The shank portions are provided with sealing surfaces arranged to mate with the opposed vertical pressure vessel sealing surfaces. A shank-spreading wedge element also disposed in the channel has at least one stop face and is engaged in the groove-like recess with the sealing member and wedge element stop face adjacent to each other

The electronic sealing system, VACOSS, as a control measure for international safeguards

International Nuclear Information System (INIS)

Kennepohl, K.; Maeckelburg, D.; Stein, G.

1979-01-01

The electronic sealing system VACOSS (Variable Coding Sealing System) was developed at KFA Juelich within the framework of an IAEA research contract. The seal is equipped with a light guide which acts as a lock. Statistical infra-red wavelength light pulses are transmitted via this light guide. The electronic components of the seal can store the opening and closing events of the light guide. In addition, the quasi-statistic treatment of code data fed into the seal by means of an adapter box guarantees an extremely high protection against unauthorized access. The portable seal is easy to handle, can be operated with a battery and can be re-used immediately after replacement of this battery. To make the seal operational code data are fed in, and the information stored in the seal can be read via the adapter box. Two versions of VACOSS were developed. VACOSS I permits the state of the seal in the facility to be checked on site only. VACOSS II can be monitored remotely by an operator passing on coded information. (author)

Optimization of Sealed Tube Graphitization Method for Environmental C-14 Studies Using MICADAS

Energy Technology Data Exchange (ETDEWEB)

Rinyu, Laszlo, E-mail: rinyu@atomki.hu [Hertelendi Laboratory of Environmental Studies, Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen (Hungary); Isotoptech Zrt., H-4025 Debrecen (Hungary); Molnar, Mihaly [Hertelendi Laboratory of Environmental Studies, Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen (Hungary); Ion Beam Physics, ETH Zuerich, CH-8093 Zuerich (Switzerland); Major, Istvan [Hertelendi Laboratory of Environmental Studies, Institute of Nuclear Research of the Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen (Hungary); Nagy, Tamas; Veres, Mihaly [Isotoptech Zrt., H-4025 Debrecen (Hungary); Kimak, Adam [University of Debrecen, H-4032 Debrecen (Hungary); Wacker, Lukas; Synal, Hans-Arno [Ion Beam Physics, ETH Zuerich, CH-8093 Zuerich (Switzerland)

2013-01-15

The original sealed tube zinc reduction graphitization process was first developed for rapid low-precision measurements of biomedical tracer samples and later also applied for high precision measurements of not too old samples. In this study we tested the MICADAS (mini radiocarbon dating system [1]) radiocarbon measurements of targets prepared by sealed tube graphitization process. We found the optimal iron catalyst and reagents (TiH{sub 2} and Zn) amount whereby we can reach a relatively low background level, and minimized the overall {delta}{sup 13}C fractionation during the graphitization. Repeated measurements of normalization standards and real samples with known {sup 14}C activities were very well reproduced. Finally, we demonstrated the applicability of the sealed tube graphitization on real environmental samples covering a wide range of {sup 14}C concentrations.

A magnetic fluid seal for rotary blood pumps: Long-term performance in liquid

Science.gov (United States)

Mitamura, Yoshinori; Takahashi, Sayaka; Amari, Shuichi; Okamoto, Eiji; Murabayashi, Shun; Nishimura, Ikuya

A magnetic fluid (MF) seal enables mechanical contact-free rotation of the shaft and hence has excellent durability. The performance of a MF seal, however, has been reported to decrease in liquids. We have developed a MF seal that has a 'shield' mechanism and a new MF with a higher magnetization of 47.9 kA/m. The sealing performance of the MF seal installed in a rotary blood pump was studied. The seal was perfect against a pressure of 150 mmHg in a continuous flow of 4.0 L/min for 275 days and against a pressure of 175 mmHg in a continuous flow of 3.9 L/min for 217 days. We have developed a MF seal that works in liquid against pressure mostly used clinically. The magnetic fluid seal is promising as a shaft seal for rotary blood pumps.

A strategy to seal exploratory boreholes in unsaturated tuff

International Nuclear Information System (INIS)

Fernandez, J.A.; Case, J.B.; Givens, C.A.; Carney, B.C.

1994-04-01

This report presents a strategy for sealing exploratory boreholes associated with the Yucca Mountain Site Characterization Project. Over 500 existing and proposed boreholes have been considered in the development of this strategy, ranging from shallow (penetrating into alluvium only) to deep (penetrating into the groundwater table). Among the comprehensive list of recommendations are the following: Those boreholes within the potential repository boundary and penetrating through the potential repository horizon are the most significant boreholes from a performance standpoint and should be sealed. Shallow boreholes are comparatively insignificant and require only nominal sealing. The primary areas in which to place seals are away from high-temperature zones at a distance from the potential repository horizon in the Paintbrush nonwelded tuff and the upper portion of the Topopah Spring Member and in the tuffaceous beds of the Calico Hills Unit. Seals should be placed prior to waste emplacement. Performance goals for borehole seals both above and below the potential repository are proposed. Detailed construction information on the boreholes that could be used for future design specifications is provided along with a description of the environmental setting, i.e., the geology, hydrology, and the in situ and thermal stress states. A borehole classification scheme based on the condition of the borehole wall in different tuffaceous units is also proposed. In addition, calculations are presented to assess the significance of the boreholes acting as preferential pathways for the release of radionuclides. Design calculations are presented to answer the concerns of when, where, and how to seal. As part of the strategy development, available technologies to seal exploratory boreholes (including casing removal, borehole wall reconditioning, and seal emplacement) are reviewed

Testing of elastomer seals using small-size rigs

International Nuclear Information System (INIS)

Leeks, C.W.E.; Dunford, B.; Barnfield, J.H.; Gray, I.L.S.

1997-01-01

This paper looks at the use of small size seal leakage test rigs to demonstrate the compliance of full size container seals against the IAEA Transport Regulation's limits for activity release for normal transport and accident conditions. The detailed requirements of the regulations are discussed and it is concluded that an appropriate test programme to meet these requirements using only small size test rigs, can normally be set up and carried out on a relatively short time scale. It is important that any small test rigs should be designed to represent the relevant features of the seal arrangement and the overall test programme should cover all of the conditions, specified by the regulations, for the type, classification and contents of the container under consideration. The parameters of elastomer O-rings, which affect their sealing ability, are considered and those which are amenable to small scale testing or have to be modelled at full size are identified. Generally, the seals used in leakage tests have to be modelled with a full size cross-section but can have a reduced peripheral length. (Author)

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.

Static and transient characteristics of the shaft seal system for helium gas circulator (Part 1)

International Nuclear Information System (INIS)

Morohoshi, S.; Saki, K.; Nemoto, M.; Taniguchi, S.; Sugimoto, A.; Kojima, M.

1982-01-01

A development program of the shaft seal system for the helium circulator supported by water lubricated bearings is presented. A seal system simulating tester and a computer program which can simulate the transient characteristics of a buffer gas seal system were newly introduced, and an investigation was performed experimentally and analytically of the characteristics of water and gas seals and of the buffer gas seal system including the control system. Main results are as follows: (1) Water seals were especially investigated in detail, and it was found that turbulence in water flow through seal clearance and deformation of seal components affected the leakage characteristics of water seals. They should be considered not only to make safety design but also to get optimum design of the seal system. (2) The calculation method for transient response of the buffer gas seal system including the control system was developed. This digital simulating method can well simulate transients encountered in the tester, and it would make a powerful tool for developing a safe seal system under steady state operation conditions and at depressurization accidents in a reactor

Performance assessment of sealing systems. Conceptual and integrated modelling of plugs and seals

Energy Technology Data Exchange (ETDEWEB)

Ruebel, Andre; Buhmann, Dieter; Kindlein, Jonathan; Lauke, Thomas

2016-08-15

The long-time isolation of radionuclides from the biosphere is the goal of the storage of radioactive waste in deep geological repositories. For repositories in rock salt, this goal is achieved on the one hand by the impermeable undisturbed part of the salt host rock formation and on the other hand by crushed salt, which is used to backfill the mine openings in the emplacement areas and galleries created during the construction of the repository. The crushed salt backfill is compacted over time and achieves a sufficiently high hydraulic resistance to avoid inflow of brines into the emplacement areas of the repository in the long-term. Plugs and seals must additionally provide their sealing function during the early post closure phase, until the compaction of the backfill is adequate and the permeability of the backfill is sufficiently low. To assess the future development of the waste repository, an adequate knowledge of the material behaviour is necessary and related mathematical models must be developed to be able to perform predictions on the long-term safety of the repository. An integrated performance assessment model was formulated that describes the long-term behaviour of a sealing built from salt concrete. The average permeability of the sealing changes with time after its emplacement from various processes of which two were regarded in a constitutive model: first, the healing of the EDZ in the host rock around the sealing, and second, the corrosion of the salt concrete material resulting from brine attack. Empirical parameter model functions were defined for both processes to reflect the actual behaviour. The mathematical model was implemented in the integrated performance assessment model LOPOS which is used by GRS as near-field model for repositories in salt. Deterministic and probabilistic calculations were performed with realistic parameters showing how the permeability of the sealing decreases during the first 2 000 years due to the healing of the EDZ

Performance assessment of sealing systems. Conceptual and integrated modelling of plugs and seals

International Nuclear Information System (INIS)

Ruebel, Andre; Buhmann, Dieter; Kindlein, Jonathan; Lauke, Thomas

2016-08-01

The long-time isolation of radionuclides from the biosphere is the goal of the storage of radioactive waste in deep geological repositories. For repositories in rock salt, this goal is achieved on the one hand by the impermeable undisturbed part of the salt host rock formation and on the other hand by crushed salt, which is used to backfill the mine openings in the emplacement areas and galleries created during the construction of the repository. The crushed salt backfill is compacted over time and achieves a sufficiently high hydraulic resistance to avoid inflow of brines into the emplacement areas of the repository in the long-term. Plugs and seals must additionally provide their sealing function during the early post closure phase, until the compaction of the backfill is adequate and the permeability of the backfill is sufficiently low. To assess the future development of the waste repository, an adequate knowledge of the material behaviour is necessary and related mathematical models must be developed to be able to perform predictions on the long-term safety of the repository. An integrated performance assessment model was formulated that describes the long-term behaviour of a sealing built from salt concrete. The average permeability of the sealing changes with time after its emplacement from various processes of which two were regarded in a constitutive model: first, the healing of the EDZ in the host rock around the sealing, and second, the corrosion of the salt concrete material resulting from brine attack. Empirical parameter model functions were defined for both processes to reflect the actual behaviour. The mathematical model was implemented in the integrated performance assessment model LOPOS which is used by GRS as near-field model for repositories in salt. Deterministic and probabilistic calculations were performed with realistic parameters showing how the permeability of the sealing decreases during the first 2 000 years due to the healing of the EDZ

Seals in nuclear reactors

International Nuclear Information System (INIS)

1979-01-01

The seals described are for use in a nuclear reactor where there are fuel assemblies in a vessel, an inlet and an outlet for circulating a coolant in heat transfer relationship with the fuel assemblies and a closure head on the vessel in a tight fluid relationship. The closure head comprises rotatable plugs which have mechanical seals disposed in the annulus around each plug while allowing free rotation of the plug when the seal is not actuated. The seal is usually an elastomer or copper. A means of actuating the seal is attached for drawing it vertically into the annulus for sealing. When the reactor coolant is liquid sodium, contact with oxygen must be avoided and argon cover gas fills the space between the bottom of the closure head and the coolant liquid level and the annuli in the closure head. (U.K.)

Investigation of positive shaft seals

Science.gov (United States)

Pfouts, J. O.

1970-01-01

Welded metal bellows secondary seals prevent secondary seal leakage with a minimum number of potential leak paths. High performance seal is obtained by controlling the potentially unstable seal-face movements induced by mechanical vibrations and fluid pressure pulsations.

A durable, non power consumptive, simple seal for rotary blood pumps.

Science.gov (United States)

Mitamura, Y; Sekine, K; Asakawa, M; Yozu, R; Kawada, S; Okamoto, E

2001-01-01

One of the key technologic requirements for rotary blood pumps is the sealing of the motor shaft. A mechanical seal, a journal bearing, magnetic coupling, and magnetic suspension have been developed, but they have drawbacks such as wear, thrombus formation, and power consumption. A magnetic fluid seal was developed for an axial flow pump. A magnetic fluid seal is durable, simple, and non power consumptive. Long-term experiments and finite element modeling (FEM) analyses confirmed these advantages. The seal body was composed of a Ned-Fe magnet and two pole pieces; the seal was formed by injecting ferrofluid into the gap (50 microm) between the pole pieces and the motor shaft. To contain the ferrofluid in the seal and to minimize the possibility of ferrofluid making contact with blood, a shield with a small cavity was attached to the pole piece. While submerged in blood, the sealing pressure of the seal was measured and found to be 188 mm Hg with ferrofluid LS-40 (saturated magnetization, 24.3 kA/m) at a motor speed of 10,000 rpm and 225 mm Hg under static conditions. The magnetic fluid seals performed perfectly at a pressure of 100 mm Hg for 594 + days in a static condition, and 51, 39+, and 34+ days at a motor speed of 8,000 rpm. FEM analyses indicated a theoretical sealing pressure of 260 mm Hg. The state of the magnetic fluid in the seal in water was observed with a microscope. Neither splashing of magnetic fluid nor mixing of the magnetic fluid and water was observed. The specially designed magnetic fluid seal for keeping liquids out is useful for axial flow blood pumps. The magnetic fluid seal was incorporated into an intracardiac axial flow pump.

Modeling the Soul Surface Seal from a Filtration Perspective

Directory of Open Access Journals (Sweden)

N.M. Somaratne

1998-01-01

Full Text Available A physically based model of soil surface scaling is proposed. The governing equations are formulated on the principle of conservation of mass assuming Darcy's law applies to suspension flowing through the soil surface. The model incorporates the physics of surface sealing by mechanisms that capture suspended particles moving with infiltrating water. As a result of particle retention in the soil system, the intrinsic porosity is reduced and hulk density is increased, resulting in changes to soil hydraulic properties such as moisture retention and hydraulic conductivity. Empirical functions are developed to describe the changes of these properties as the seal develops. With this approach, the seal can be mathematically described by well defined initial and boundary conditions and transient seal properties can be simulated in a physically realistic manner.

Windpower and grey seals: An impact assessment of potential effects by sea-based windpower plants in a local seal population

International Nuclear Information System (INIS)

Sundberg, Jan; Soederman, Malin

2000-05-01

The impact of five sea-based wind power plants on two haulout sites for grey seals on southwestern Gotland, in the Baltic Sea, was analysed. Data on seal numbers was collected on a regular basis during the initial stages of the project from summer 1996, continuing during the building (autumn 1997) and running of the wind power plants (from spring 1998) until the end of June 1999. Additional observational data from earlier years was also available. Indications of lower occurrence and reduced number of seals in the area was found during periods of time in 1997 and 1998, times of construction and active running of the plants. However, no evidence on the wind power plants, per se, affecting the grey seals was found. Instead, several weather factors were found to affect the number of seals in the area, and periods of low occurrence and number of seals were more likely explained by i.e. unfavourable water levels and hard wind from certain directions. One important, short term, impact factor was however found. Human induced disturbances such as boat and helicopter traffic, some which were directly related to maintenance of the wind power plants, temporarily reduced number of seals and made them more restless. Disturbance thus constitutes a potential threat to seals. A shift from one to the other of the two haulout sites was also noted, a shift which likely is due to disturbances. Future guidelines are given, including some restrictions in movements near the haulout sites. Continued observations and studies are suggested if more off-shore wind power plants will be raised in the area. A call for more stringent use of environmental impact assessments is thus made. Also, suggestions on measures to be taken in order to reduce the effect of human related disturbances are made. In order to create sustainable conditions for a continued population of seals in the area and in order to create opportunities for a reestablishment of the grey seal in the southern Baltic region

Windpower and grey seals: An impact assessment of potential effects by sea-based windpower plants in a local seal population

Energy Technology Data Exchange (ETDEWEB)

Sundberg, Jan; Soederman, Malin [Uppsala Univ. (Sweden). Dept. of Animal Ecology

2000-05-01

The impact of five sea-based wind power plants on two haulout sites for grey seals on southwestern Gotland, in the Baltic Sea, was analysed. Data on seal numbers was collected on a regular basis during the initial stages of the project from summer 1996, continuing during the building (autumn 1997) and running of the wind power plants (from spring 1998) until the end of June 1999. Additional observational data from earlier years was also available. Indications of lower occurrence and reduced number of seals in the area was found during periods of time in 1997 and 1998, times of construction and active running of the plants. However, no evidence on the wind power plants, per se, affecting the grey seals was found. Instead, several weather factors were found to affect the number of seals in the area, and periods of low occurrence and number of seals were more likely explained by i.e. unfavourable water levels and hard wind from certain directions. One important, short term, impact factor was however found. Human induced disturbances such as boat and helicopter traffic, some which were directly related to maintenance of the wind power plants, temporarily reduced number of seals and made them more restless. Disturbance thus constitutes a potential threat to seals. A shift from one to the other of the two haulout sites was also noted, a shift which likely is due to disturbances. Future guidelines are given, including some restrictions in movements near the haulout sites. Continued observations and studies are suggested if more off-shore wind power plants will be raised in the area. A call for more stringent use of environmental impact assessments is thus made. Also, suggestions on measures to be taken in order to reduce the effect of human related disturbances are made. In order to create sustainable conditions for a continued population of seals in the area and in order to create opportunities for a reestablishment of the grey seal in the southern Baltic region

Ferrules seals

Science.gov (United States)

Smith, J.L.

1984-07-10

A device is provided for sealing an inner tube and an outer tube without excessively deforming the tubes. The device includes two ferrules which cooperate to form a vacuum-tight seal between the inner tube and outer tube and having mating surfaces such that overtightening is not possible. 3 figs.

Management of disused high-activity sealed radioactive sources: Opting for removal from the national territory

Energy Technology Data Exchange (ETDEWEB)

Mourão, Rogério Pimenta, E-mail: mouraor@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Since 2007 Brazil has been using the removal from its territory as a strategy for the management of sealed sources. Three campaigns have been carried out so far, each aiming at specific source types or categories. In the first of these campaigns in 2007, 126 neutron sources of American origin were repatriated to the USA, followed in 2010 by around 900 low activity sources (Categories 3 to 5, according to the IAEA classification system). Both operations were conducted by teams of the American institute Los Alamos National Laboratory. A third campaign, focused on high activity sources – essentially Cobalt-60 sources for teletherapy – was carried out between 2016 and 2017 and resulted in 81 spent high activity radioactive sources of American- and Canadian-origin been sent to Germany and the USA. This operation was carried out by a team of South Africa using a dedicated Mobile Hot Cell. The benefits to Brazil resulting from these operations are clear: increase in safety and security; availability of new precious storage space; less effort dedicated to the disused sealed sources storage; less space in the future borehole facility; financial gains in the selling or reuse of steel, lead and depleted uranium from the original shields. An overexposure incident occurred during the operation, in which a worker was exposed to a dose above the annual statutory limit. (author)

Borehole sealing method and apparatus

International Nuclear Information System (INIS)

Hartley, J.N.; Jansen, G. Jr.

1977-01-01

A method and apparatus is described for sealing boreholes in the earth. The borehole is blocked at the sealing level, and a sealing apparatus capable of melting rock and earth is positioned in the borehole just above seal level. The apparatus is heated to rock-melting temperature and powdered rock or other sealing material is transported down the borehole to the apparatus where it is melted, pooling on the mechanical block and allowed to cool and solidify, sealing the hole. Any length of the borehole can be sealed by slowly raising the apparatus in the borehole while continuously supplying powdered rock to the apparatus to be melted and added to the top of the column of molten and cooling rock, forming a continuous borehole seal. The sealing apparatus consists of a heater capable of melting rock, including means for supplying power to the heater, means for transporting powdered rock down the borehole to the heater, means for cooling the apparatus and means for positioning the apparatus in the borehole. 5 claims, 1 figure

Considerations in the safety assessment of sealed nuclear facilities

International Nuclear Information System (INIS)

1991-06-01

This report is a part of the International Atomic Energy Agency's radioactive waste management programme, whose objective is to provide assistance to Member States in developing guidance for identifying safe alternatives for isolating radioactive waste from man and his environment. This report attempts to integrate information from the previous reports on decommissioning of nuclear facilities, mitigation of accidents at such facilities, and performance assessment of disposal systems to provide useful advice and qualitative guidance to those responsible for performance and safety assessments of sealed nuclear facilities by giving an overview of possible approaches and techniques for such assessments. In this context, the establishment of requirements and rules governing the radiological safety of personnel, the general public, and the environment for sealing and post-sealing activities will enable the choice of the most appropriated approach and help to promote consistency in both decommissioning and waste management standards. The near-field effects discussed in this document include gas generation, interactions of the groundwater and the residual water with other components of the system, thermal, thermo-mechanical, radiation effects and chemical and geochemical reactions. 59 refs, figs and tabs

Inflatable door seals - reduced maintenance and longer service-life

International Nuclear Information System (INIS)

Kuran, S.; Wensel, R.; Lazic, M.

1995-01-01

Inflatable door seals, designed more than a quarter of a century ago, have given good service in Canadian and overseas CANDU reactors. These thin-walled elastomeric seals have been exposed to many thousands of cycles of inflation and deflation, various types of aging (temperature, radiation and time), ozone degradation, abrasion, pinching, stiction, cracking and installation damage. The fact that they have operated successfully as part of the reactor building containment structure - subjected to the same pressures and temperatures as those for the thick reinforced concrete walls and steel doors highlights the achievement of these thin rubber seals. However, in the last decade, the rubber industry has developed new compounds that are more resistant to radiation, temperature, and time-dependent aging. Components manufactured from such compounds are less prone to hardening, stress cracking and permanent set; thereby saving on replacement costs, inventory and overall maintenance. This paper discusses development and testing of recent material and design changes to inflatable seals, and addresses various practical issues faced by the operations engineers and maintainers using these seals. (author)

α-sealed transfer device and portable plastic film sealers

International Nuclear Information System (INIS)

Fu Zhujun; Shan Ruixia

1990-04-01

An α transfer device which can be operated remotely is presented. The device is able to perform sealed transfer of radioactive articles from a hot cell or shielded glove box to the outside and non-radioactive articles from the outside to a hot cell or shielded glove box by using bag sealing technology. The structure of the transfer device is simple. Its operation is safe and reliable. The sealing performance of the device is very good (for alpha). The use of this transfer device will greatly reduce α contamination of the building and creates a favourable condition for operating radioactive materials in an undivided area. The portable heat sealing device is also a necessary tool in bag sealing technology and α-sealed transfer. Two types of portable plastic film sealers have been developed. Their structure is simple. The operation of the portable plastic film sealers is easy. Their performance is also excellent. Both the α-sealed transfer device and portable plastic film sealers are very useful to the reprocessing plant of nuclear fuel

Long-term brine migration through an engineered shaft seal system

International Nuclear Information System (INIS)

Fryar, D.G.; Beach, J.A.; Kelley, V.A.; Knowles, M.K.

1997-01-01

The shaft seal system for the Waste Isolation Pilot Plant (WIPP) must provide a barrier to the migration of fluids within the shafts to prevent the release of contaminants to the accessible environment. To investigate the performance of the shaft seal system, a set of fluid flow performance models was developed based upon the physical characteristics of the WIPP shaft seal system and the surrounding geologic media. This paper describes the results of a numerical model used to investigate the long-term potential for brine migration through the shaft seal system. Modeling results demonstrate that the WIPP shaft seal system will effectively limit brine migration within the repository shafts

Regenerator cross arm seal assembly

Science.gov (United States)

Jackman, Anthony V.

1988-01-01

A seal assembly for disposition between a cross arm on a gas turbine engine block and a regenerator disc, the seal assembly including a platform coextensive with the cross arm, a seal and wear layer sealingly and slidingly engaging the regenerator disc, a porous and compliant support layer between the platform and the seal and wear layer porous enough to permit flow of cooling air therethrough and compliant to accommodate relative thermal growth and distortion, a dike between the seal and wear layer and the platform for preventing cross flow through the support layer between engine exhaust and pressurized air passages, and air diversion passages for directing unregenerated pressurized air through the support layer to cool the seal and wear layer and then back into the flow of regenerated pressurized air.

Aerial surveys of seals at Rødsand seal sanctuary and adjacent haul-out sites

DEFF Research Database (Denmark)

Teilmann, J.; Dietz, R.; Edren, Susi M.C.

This report describes the preliminary results of aerial surveys at Rødsand seal sanctuary, southeast Denmark and adjacent seal haul-out sites in southwestern Baltic. The work was carried out in connection with studies of potential effects of the Nysted offshore wind farm. Rødsand seal sanctuary...... is a part of seal management area 4, and the area is believed to hold a more or less closed population with little exchange to other areas. Although the harbour seal is relatively stationary there may be movements between the haul-out sites in the area. A possible reaction to disturbance from...... the construction and operation of the wind farm may be that the seals use other haul-out sites to a higher extend....

THE PROBLEMS OF USING EXEMPTION ACTIVITY VALUES FOR REGULATING THE MANAGEMENT OF SEALED RADIONUCLIDE SOURCES OF GAMMA-RADIATION

Directory of Open Access Journals (Sweden)

A. N. Barkovsky

2017-01-01

Full Text Available The article focuses on the procedure for exemption of the sealed and unsealed radionuclide sources of gamma radiation from regulatory control. The contradictory nature of the existing set of exemption criteria has been noted, leading, in some cases, to paradoxical situations. It is shown that the exempt activity values determined in NRB-99/2009 and in the international basic safety standards of the IAEA are significantly overestimated (in comparison with the activity values of a point source creating the ambient dose equivalent rate of 1 μSv / h at a distance of 0.1 m for a number of the most widely used gamma-emitting radionuclides, including 22Na, 54Mn, 75Se, 152Eu and 154Eu. It is proposed to revise the current values of exempt activity, bringing them in line with the dose rate criterion for the exempt of sealed radionuclide sources of gamma radiation, and to present them with one significant digit. The corrected values of exempt activity for  seven selected radionuclides are proposed for further use in the process of revision of the national radiation safety standards.

Leakage Account for Radial Face Contact Seal in Aircraft Engine Support

Science.gov (United States)

Vinogradov, A. S.; Sergeeva, T. V.

2018-01-01

The article is dedicated to the development of a methodology for the radial face contact seal design taking into consideration the supporting elements deformations in different aircraft engine operating modes. Radial face contact seals are popular in the aircraft engines bearing support. However, there are no published leakage calculation methodologies of these seals. Radial face contact seal leakage is determined by the gap clearance in the carbon seal ring split. In turn, the size gap clearance depends on the deformation of the seal assembly parts and from the engine operation. The article shows the leakage detection sequence in the intershaft radial face contact seal of the compressor support for take-off and cruising modes. Evaluated calculated leakage values (2.4 g/s at takeoff and 0.75 g/s at cruising) go with experience in designing seals.

Repository sealing concepts for the Nevada nuclear waste storage Investigations Project

International Nuclear Information System (INIS)

Fernandez, J.A.; Freshley, M.D.

1984-08-01

This report describes concepts for sealing a nuclear waste repository in an unsaturated tuff environment. The repository site under consideration is Yucca Mountain, which is on and adjacent to the Nevada Test Site. The hydrogeology of Yucca Mountain, preliminary repository concepts, functional requirements and performance criteria for sealing, federal and state regulations, and hydrological calculations are considered in developing the sealing concepts. Water flow through the unsaturated zone is expected to be small and generally vertically downward with some potential to occur through discrete fault and fracture zones. These assumptions are used in developing sealing concepts for shafts, ramps, and boreholes. Sealing of discrete, water-producing faults and fracture zones encountered in horizontal emplacement holes and in access and emplacement drifts is also described. 49 references, 21 figures, 6 tables

Population development and status of harbour seals (Phoca vitulina in the Wadden Sea

Directory of Open Access Journals (Sweden)

Peter JH Reijnders

2010-09-01

Full Text Available An index for the condition of a population should include a measure of the recuperative power or resilience of the population in question. This measure needs to cover both the demographic and physiological condition of the population. Applied to the harbour seal population in the Wadden Sea we therefore address respectively the population development and distribution, and its health condition, and relate these to environmental conditions. The harbour seal population has been severely depleted by hunting in the first half of the 20th century. After hunting was stopped in the mid-1970s the population recovered gradually. This recovery was twice interrupted by Phocine Distemper Virus (PDV outbreaks in 1988 and 2002. These PDV-epizootics reduced the population by 57% and 50% respectively. They also lead to changes in age and sex structure of the population, which gradually returned to a stable age-structure. Despite the reduction in population size by respectively 57% and 50%, the population showed a strong recovery with a growth rate close to the considered maximum possible for this species. The observed changes in the distribution of the population over the 4 sub-regions indicate that distribution is not a static phenomenon. Long term field and pathological investigations point out that the general health status of the population has improved, particularly that of newborn seals (0-6months old. The increasing prevalence of parasites in lungs and intestine warrants continued monitoring of the health status of seals. This is especially relevant in view of the exponential increase of the population, which may finally approach the carrying capacity of the area. Concluding, we canstate that the condition of the population in terms of demographic and health parameters is satisfactory. The best guarantee for maintaining such a favourable conservation status is to abstain from human interferences (e.g. rescue, rehabilitation and release with natural

Simulation Analysis of Spherical Mechanical Seal Property of Marine Stern Shaft

Directory of Open Access Journals (Sweden)

Zhou Xu Hui

2016-01-01

Full Text Available The finite element model of spherical mechanical seal wasestablished with ANSYS, and the influence of seawater pressure, shaft speed and other factors on the sealing performance was discussed. The study results show that local contact situation of the spherical mechanical seal is in the outside of the seal rings, and both maximum contact pressure and temperature appearat the same position. As sea water pressure and stern shaft rotary speed are increased, the contact pressure and temperature of the spherical seal surface are raised, and when the contact pressure of seal surface is 0, the spherical seal surface forms two zones including contact one and clearance zone. The former is near the outside of the seal ring, the lateris close to the inside of one. These research results are of important theoretical significance and engineering application value for the development of new kinds of mechanical seals, and improvement of both safety and survivability of underwater vehicles.

Ceramic/metal seals. [refractory materials for hermetic seals for lighium-metal sulfide batteries

Science.gov (United States)

Bredbenner, A. M.

1977-01-01

Design criteria are discussed for a hermetic seal capable of withstanding the 450 C operating temperature of a lithium-metal sulfide battery system. A mechanical seal consisting of two high strength alloy metal sleeves welded or brazed to a conductor assembly and pressed onto a ceramic is described. The conductor center passes through the ceramic but is not sealed to it. The seal is effected on the outside of the taper where the tubular part is pressed down over and makes contact.

High speed cryogenic self-acting, shaft seals for liquid rocket turbopumps

Science.gov (United States)

Burcham, R. E.

1983-01-01

Three self acting lift pad liquid oxygen face seals and two self acting gaseous helium circumferential seals for high speed liquid oxygen turbopump were evaluated. The development of a technology for reliable, 10 hour life, multiple start seals for use in high speed liquid oxygen turbopumps is discussed.

Nuclear instrumentation cable end seal

International Nuclear Information System (INIS)

Cannon, C.P.; Brown, D.P.

1979-01-01

An improved coaxial end seal for hermetically sealed nuclear instrumentation cable exhibiting an improved breakdown pulse noise characteristic under high voltage, high temperature conditions is described. A tubular insulator body has metallized interior and exterior surface portions which are braze sealed to a center conductor and an outer conductive sheath. The end surface of the insulator body which is directed toward the coaxial cable to which it is sealed has a recessed surface portion within which the braze seal material terminates

Bringing Antarctic Weddell seals to the classroom through PolarTREC

Science.gov (United States)

Eilers, A. A.

2017-12-01

PolarTREC (Teachers and Researchers Exploring and Collaborating) is an NSF funded professional development opportunity in which K-12 teachers and informal educators participated in hands-on field research experiences in the Polar Regions. The program goal is to invigorate polar science education and understanding by bringing together educators and polar researchers. This unique opportunity for educators has two main components: a 4-6 week field experience and a classroom/community connection piece. In preparation for these experiences, museum educator Alex Eilers and science team lead Dr. Jennifer Burns planned, developed and executed extensive outreach efforts for both students and the community to highlight the Weddell seal research project during the 2012, 2014 and 2016 seasons. The following outreach activities summarize the team's most successful attempts at engaging schoolchildren, teachers and the public, creating a broader impact of the Weddell seal scientific project. On-line Daily journal entries were uploaded to the PolarTREC website encouraging an active interaction between the science team and participants. A Polar Connect event offered participants a real-time, interactive internet presentation with the team. Schools A multitude of on-site presentations were made in classrooms, at teacher workshops and faculty meetings. Two 45 minute labs were developed for students visiting the museum, Animals of the Antarctic and Journey to the Poles, the latter is now included in our ongoing program repertoire. Two travelling kits, Extreme Cold Weather Gear and The Weddell Seal, were developed by museum staff and continue to circulate through schools. A multi-lesson educational module was developed by museum staff to bridge the gap between the scientific research conducted in the field and students in grades 3-8. It contains curriculum-based lessons, field data and strategic methods to assist students in analyzing the data. Community Community-wide interest

Field Trial of an Aerosol-Based Enclosure Sealing Technology

Energy Technology Data Exchange (ETDEWEB)

Harrington, Curtis [Univ. of California, Davis, CA (United States); Springer, David [Alliance for Residential Building Innovation (ARBI), Davis, CA (United States)

2015-09-01

This report presents the results from several demonstrations of a new method for sealing building envelope air leaks using an aerosol sealing process developed by the Western Cooling Efficiency Center at UC Davis. The process involves pressurizing a building while applying an aerosol sealant to the interior. As air escapes through leaks in the building envelope, the aerosol particles are transported to the leaks where they collect and form a seal that blocks the leak. Standard blower door technology is used to facilitate the building pressurization, which allows the installer to track the sealing progress during the installation and automatically verify the final building tightness. Each aerosol envelope sealing installation was performed after drywall was installed and taped, and the process did not appear to interrupt the construction schedule or interfere with other trades working in the homes. The labor needed to physically seal bulk air leaks in typical construction will not be replaced by this technology.

Uncertainties in sealing a nuclear waste repository in partially saturated tuff

International Nuclear Information System (INIS)

Tillerson, J.R.; Fernandez, J.A.; Hinkebein, T.E.

1989-01-01

Sealing a nuclear waste repository in partially saturated tuff presents unique challenges to assuring performance of sealing components. Design and performance of components for sealing shafts, ramps, drifts, and exploratory boreholes depend on specific features of both the repository design and the site; of particular importance is the hydrologic environment in the unsaturated zone, including the role of fracture flow. Repository design features important to sealing of a repository include the size and location of shaft and ramp accesses, excavation methods, and the underground layout features such as grade (drainage direction) and location relative to geologic structure. Uncertainties about seal components relate to the postclosure environment for the seals, the emplacement methods, the material properties, and the potential performance of the components. An approach has been developed to reduce uncertainties and to increase confidence in seal performance; it includes gathering extensive site characterization data, establishing conservative design requirements, testing seal components in laboratory and field environments, and refining designs of both the seals and the repository before seals are installed. 9 refs., 5 figs., 2 tabs

Design of repository sealing systems - 1981

International Nuclear Information System (INIS)

Ellison, R.D.; Shukla, D.K.; Kelsall, P.C.; D'Appolonia Consulting Engineers, Albuquerque, NM)

1982-01-01

Isolating nuclear waste in geologic repositories will require the sealing of penetrations such as access shafts and tunnels, disposal rooms, and exploration boreholes. This paper discusses seal designs developed for a repository in bedded salt referenced to the stratigraphy of southeastern New Mexico. Designs are based on a multiple component concept whereby individual components are designed for a specific function and location. For a repository in salt the major function of the seals is to exclude groundwater inflow. Two main types of component are included for this purpose: (1) bulk-heads are dense concrete structures keyed into the walls of the penetration and are intended to reduce flow at the interface between the seal and the salt; (2) backfills are granular materials compacted in place in the penetration. In the repository the major backfill material is crushed salt, which is expected to consolidate and recrystallize as the rooms close in response to salt creep. Densely compacted clays will be used as backfill in the shafts closer to potential sources of water inflow. 22 references, 10 figures, 1 table

Turbine interstage seal with self-balancing capability

Science.gov (United States)

Mills, Jacob A; Jones, Russell B; Sexton, Thomas D

2017-09-26

An interstage seal for a turbine of a gas turbine engine, the interstage seal having a seal carrier with an axial extending seal tooth movable with a stator of the engine, and a rotor with a seal surface that forms the interstage seal with the seal tooth, where a magnetic force produced by two magnets and a gas force produced by a gas pressure acting on the seal carrier forms a balancing force to maintain a close clearance of the seal without the seal tooth contacting the rotor seal surfaces during engine operation. In other embodiments, two pairs of magnets produce first and second magnetic forces that balance the seal in the engine.

High performance sealing - meeting nuclear and aerospace requirements

International Nuclear Information System (INIS)

Wensel, R.; Metcalfe, R.

1994-11-01

Although high performance sealing is required in many places, two industries lead all others in terms of their demand-nuclear and aerospace. The factors that govern the high reliability and integrity of seals, particularly elastomer seals, for both industries are discussed. Aerospace requirements include low structural weight and a broad range of conditions, from the cold vacuum of space to the hot, high pressures of rocket motors. It is shown, by example, how a seal can be made an integral part of a structure in order to improve performance, rather than using a conventional handbook design. Typical processes are then described for selection, specification and procurement of suitable elastomers, functional and accelerated performance testing, database development and service-life prediction. Methods for quality assurance of elastomer seals are summarized. Potentially catastrophic internal dejects are a particular problem for conventional non-destructive inspection techniques. A new method of elastodynamic testing for these is described. (author)

Reactor coolant pump shaft seal behavior during blackout conditions

International Nuclear Information System (INIS)

Mings, W.J.

1985-01-01

The United States Nuclear Regulatory Commission has classified the problem of reactor coolant pump seal failures as an unresolved safety issue. This decision was made in large part due to experimental results obtained from a research program developed to study shaft seal performance during station blackout and reported in this paper. Testing and analysis indicated a potential for pump seal failure under postulated blackout conditions leading to a loss of primary coolant with a concomitant danger of core uncovery. The work to date has not answered all the concerns regarding shaft seal failure but it has helped scope the problem and focus future research needed to completely resolve this issue

Conditioning of disused sealed sources in countries without disposal facility: Short term gain - long term pain

International Nuclear Information System (INIS)

Benitez-Navarro, J.C.; Salgado-Mojena, M.

2002-01-01

Owing to the considerable development in managing disused sealed radioactive sources (DSRS), the limited availability of disposal practices for them, and the new recommendations for the use of borehole disposal concept, it was felt that a paper reviewing the existing recommendations could be a starting point of discussion on the retrievability of the sources. Even when no international consensus exists as to an acceptable solution for the challenge of disposal of disused sealed sources, the 'Best Available Technology' for managing most of them, recommended for developing countries, included the cementation of the sources. The waste packages prepared in such a way do not allow any flexibility to accommodate possible future disposal requirements. Therefore, the 'Wait and See' approach could be also recommended for managing not only the sources with long-live radionuclides and high activity, but probably for all kind of existing disused sealed sources. The general aim of the current paper is to identify and review the current recommendations for managing disused sealed sources and to meditate on the most convenient management schemes for disused sealed radioactive sources in Member States without disposal capacities (Latin America, Africa). The risk that cemented DSRS could be incompatible with future disposal requirements was taken into account. (author)

Sealing a conduit end

International Nuclear Information System (INIS)

Mentz, R.M.

1993-01-01

An apparatus for sealing or blocking conduits, such as the primary nozzles of a nuclear steam generator is described. It includes an annular bracket sealingly attached to the open end of the nozzle, the bracket having a plurality of threaded holes therein. Mounted atop the bracket is a generally circular nozzle dam for covering the opening. Interposed between the nozzle dam and the bracket is an extrusion-resistant seal member having a plurality of apertures therethrough for receiving each bolt. The seal member is configured to resist extrusion by having laminated layers of differing hardnesses, so that the seal member will not laterally extrude away from each bolt in a manner that enlarges the aperture surrounding each bolt as the nozzle dam is bolted to the bracket. (author)

Hermetic Seal Leak Detection Apparatus

Science.gov (United States)

Kelley, Anthony R. (Inventor)

2013-01-01

The present invention is a hermetic seal leak detection apparatus, which can be used to test for hermetic seal leaks in instruments and containers. A vacuum tight chamber is created around the unit being tested to minimize gas space outside of the hermetic seal. A vacuum inducing device is then used to increase the gas chamber volume inside the device, so that a slight vacuum is pulled on the unit being tested. The pressure in the unit being tested will stabilize. If the stabilized pressure reads close to a known good seal calibration, there is not a leak in the seal. If the stabilized pressure reads closer to a known bad seal calibration value, there is a leak in the seal. The speed of the plunger can be varied and by evaluating the resulting pressure change rates and final values, the leak rate/size can be accurately calculated.

Distribution, abundance and biology of ringed seals (Phoca hispida: an overview

Directory of Open Access Journals (Sweden)

Randall R Reeves

1998-06-01

potential impacts of industrial activity and pollution on ringed seals, such impacts have been documented only in limited areas. Because of their ubiquitous occurrence and availability for sampling, ringed seals are good subjects for monitoring contaminant trends in Arctic marine food chains.

Reusable, tamper-indicating seal

International Nuclear Information System (INIS)

Ryan, M.J.

1978-01-01

A reusable, tamper-indicating seal is comprised of a drum confined within a fixed body and rotatable in one direction therewithin, the top of the drum constituting a tray carrying a large number of small balls of several different colors. The fixed body contains parallel holes for looping a seal wire therethrough. The base of the drums carries cams adapted to coact with cam followers to lock the wire within the seal at one angular position of the drum. A channel in the fixed body, visible from outside the seal, adjacent the tray constitutes a segregated location for a small plurality of the colored balls. A spring in the tray forces colored balls into the segregated location at one angular position of the drum, further rotation securing the balls in position and the wires in the seal. A wedge-shaped plough removes the balls from the segregated location, at a different angular position of the drum, the wire being unlocked at the same postion. A new pattern of colored balls will appear in the segregated location when the seal is relocked

Leakage limits for inflatable seals of sodium cooled fast breeder reactor

Energy Technology Data Exchange (ETDEWEB)

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

2014-01-15

Highlights: • All possible types/modes of gas escape covered. • Limits include simultaneous contributions from bypass and permeation leakage modes. • Leakage of radioactive cover gas with fission products assumed. • Possibility of sodium frost deposition in sealed gap considered. • Cover gas activity decay during fuel handling and relative importance of types/modes of leakage considered for realistic results and simpler seal design. -- Abstract: Estimation and stipulation of allowable leakage for inflatable seals of 500 MWe Prototype Fast Breeder Reactor is depicted. Leakage limits are specified using a conservative approach, which assumes escape of radioactive cover gas with fission products across the seals in bypass and permeation modes and possibility of sodium frost deposition in sealed gaps because of permeation leakage of inflation gas. Procedures to arrive at the allowable leakages of argon cover gas (normal-operation/fuel-handling: 10{sup −3}/10{sup −2} scc/s/m length of seal) and argon inflation gas (10{sup −3} scc/s/m length of seal) is described.

Double angle seal forming lubricant film

Science.gov (United States)

Ernst, William D.

1984-01-01

A lubricated piston rod seal which inhibits gas leaking from a high pressure chamber on one side of the seal to a low pressure chamber on the other side of the seal. A liquid is supplied to the surface of the piston rod on the low pressure side of the seal. This liquid acts as lubricant for the seal and provides cooling for the rod. The seal, which can be a plastic, elastomer or other material with low elastic modulus, is designed to positively pump lubricant through the piston rod/seal interface in both directions when the piston rod is reciprocating. The capacity of the seal to pump lubricant from the low pressure side to the high pressure side is less than its capacity to pump lubricant from the high pressure side to the low pressure side which ensures that there is zero net flow of lubricant to the high pressure side of the seal. The film of lubricant between the seal and the rod minimizes any sliding contact and prevents the leakage of gas. Under static conditions gas leakage is prevented by direct contact between the seal and the rod.

Rotatable seal assembly

International Nuclear Information System (INIS)

Garibaldi, J.L.; Logan, C.M.

1982-01-01

An assembly is provided for rotatably supporting a rotor on a stator so that vacuum chambers in the rotor and stator remain in communication while the chambers are sealed from ambient air, which enables the use of a ball bearing or the like to support most of the weight of the rotor. The apparatus includes a seal device mounted on the rotor to rotate therewith, but shiftable in position on the rotor while being sealed to the rotor as by an oring. The seal device has a flat face that is biased towards a flat face on the stator, and pressurized air is pumped between the faces to prevent contact between them while spacing them a small distance apart to avoid the inflow of large amounts of air between the faces and into the vacuum chambers

Recent advances in magnetic liquid sealing

International Nuclear Information System (INIS)

Raj, K.; Stahl, P.; Bottenberg, W.; True, D.; Martis, G.; Zook, C.

1979-01-01

In this paper recent work in design and testing of two special magnetic liquid seals extending the state-of-the-art of ferrofluidic sealing is discussed. These custom seals are a moving belt edge seal and an exclusion seal. The first seal provides a hermetic barrier to solid particulates expected to be present in enclosed nuclear environments. The second seal is used on a magnetic disk drive spindle and reduces the particulate contaminants in the memory disk pack area by up to three orders of magnitude. In addition, bearing life in the spindle is found to be doubled due to reduction of operating temperature. The fundamentals of magnetic fluid sealing are presented in terms of magnetic circuit design and physical properties of ferrofluids

Releasable, high-pressure seal and method of forming same

International Nuclear Information System (INIS)

Holman, R.R.; Turkail, D.N.

1980-01-01

An inexpensive releaseable, high-pressure seal was developed, which can withstand pressures over 70 atm, and is particularly useful for nuclear reactors where remote-handling equipment must be used to access the flanged connections. It is smaller than existing high-pressure seals and does not require as many bolts. The fail-safe quality of the seal does not depend on close tolerances or high-quality surface finishes. The seal comprises two conduits through which the high-pressure fluid flows, each fitted with flanges. The second flange has a periphery attached to the second conduit. Each flange has a central opening for the fluid to flow through. The second flange is frustoconical in shape and is resilient so that a portion of it near its central opening can be resiliently biased towards the first flange. A seal ring between the end flanges seals the interior of the conduits from the exterior. A force is applied to the seal ring which acts nearly parallel to the axis of the conduits and varies as a function of the fluid pressure inside of the conduits. The flanges are attached to each other with peripheral collars via a circumferential clamp. (DN)

Concentrations, patterns and metabolites of organochlorine pesticides in relation to xenobiotic phase I and II enzyme activities in ringed seals (Phoca hispida) from Svalbard and the Baltic Sea

International Nuclear Information System (INIS)

Routti, Heli; Bavel, Bert van; Letcher, Robert J.; Arukwe, Augustine; Chu Shaogang; Gabrielsen, Geir W.

2009-01-01

The present study investigates the concentrations and patterns of organochlorine pesticides (OCPs) and their metabolites in liver and plasma of two ringed seal populations (Phoca hispida): lower contaminated Svalbard population and more contaminated Baltic Sea population. Among OCPs, p,p'-DDE and sum-chlordanes were the highest in concentration. With increasing hepatic contaminant concentrations and activities of xenobiotic-metabolizing enzymes, the concentrations of 3-methylsulfonyl-p,p'-DDE and the concentration ratios of pentachlorophenol/hexachlorobenzene increased, and the toxaphene pattern shifted more towards persistent Parlar-26 and -50 and less towards more biodegradable Parlar-44. Relative concentrations of the chlordane metabolites, oxychlordane and -heptachlorepoxide, to sum-chlordanes were higher in the seals from Svalbard compared to the seals from the Baltic, while the trend was opposite for cis- and trans-nonachlor. The observed differences in the OCP patterns in the seals from the two populations are probably related to the catalytic activity of xenobiotic-metabolizing enzymes, and also to differences in dietary exposure. - Contrasting patterns of organochlorine pesticides in two ringed seal populations.

Concentrations, patterns and metabolites of organochlorine pesticides in relation to xenobiotic phase I and II enzyme activities in ringed seals (Phoca hispida) from Svalbard and the Baltic Sea

Energy Technology Data Exchange (ETDEWEB)

Routti, Heli, E-mail: heli.routti@npolar.n [Norwegian Polar Institute, Polar Environmental Centre, 9296 Tromso (Norway); Centre of Excellence in Evolutionary Genetics and Physiology, Department of Biology, University of Turku, 20014 Turku (Finland); Bavel, Bert van [MTM Research Centre, Orebro University, 70182 Orebro (Sweden); Letcher, Robert J. [Wildlife Toxicology and Disease Program, Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment Canada, National Wildlife Research Centre, Carleton University, Ottawa, Ontario K1A 0H3 (Canada); Arukwe, Augustine [Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Chu Shaogang [Wildlife Toxicology and Disease Program, Wildlife and Landscape Science Directorate, Science and Technology Branch, Environment Canada, National Wildlife Research Centre, Carleton University, Ottawa, Ontario K1A 0H3 (Canada); Gabrielsen, Geir W. [Norwegian Polar Institute, Polar Environmental Centre, 9296 Tromso (Norway)

2009-08-15

The present study investigates the concentrations and patterns of organochlorine pesticides (OCPs) and their metabolites in liver and plasma of two ringed seal populations (Phoca hispida): lower contaminated Svalbard population and more contaminated Baltic Sea population. Among OCPs, p,p'-DDE and sum-chlordanes were the highest in concentration. With increasing hepatic contaminant concentrations and activities of xenobiotic-metabolizing enzymes, the concentrations of 3-methylsulfonyl-p,p'-DDE and the concentration ratios of pentachlorophenol/hexachlorobenzene increased, and the toxaphene pattern shifted more towards persistent Parlar-26 and -50 and less towards more biodegradable Parlar-44. Relative concentrations of the chlordane metabolites, oxychlordane and -heptachlorepoxide, to sum-chlordanes were higher in the seals from Svalbard compared to the seals from the Baltic, while the trend was opposite for cis- and trans-nonachlor. The observed differences in the OCP patterns in the seals from the two populations are probably related to the catalytic activity of xenobiotic-metabolizing enzymes, and also to differences in dietary exposure. - Contrasting patterns of organochlorine pesticides in two ringed seal populations.

Seal-rotordynamic-coefficient Test Results for a Model SSME ATD-HPFTP Turbine Interstage Seal with and Without a Swirl Brake

Science.gov (United States)

Childs, Dara W.; Ramsey, Christopher

1991-01-01

The predictions of Scharrer's (1988) theory for rotordynamic coefficients of labyrinth gas seals were compared with measurements for a model SSME Alternate Turbopump Development High Pressure Fuel Turbopump with and without swirl brakes. Using the test apparatus described by Childs et al., tests were conducted with supply pressures up to 18.3 bars and speeds up to 16,000 rpm. Seal back pressure was controlled to provide four pressure ratios at all supply pressures. No measurable differences in leakage was detected for the seal with and without the swirl brakes. Comparisons of the measurement results for the seal without a swirl brake with the Scharrer theory showed that the theory can be used only to provide design guidelines; systematic differences were observed between theory and experiment due to changes in running speed, supply pressure, and pressure ratio.

Seal-rotordynamic-coefficient test results for a model SSME ATD-HPFTP turbine interstate seal with and without a swirl brake

Science.gov (United States)

Childs, D. W.; Ramsey, C.

1991-01-01

The predictions of Scharrer's (1988) theory for rotordynamic coefficients of labyrinth gas seals were compared with measurements for a model SSME Alternate Turbopump Development High-Pressure Fuel Turbopump with and without swirl brakes. Using the test apparatus described by Childs et al. (1986, 1990), tests were conducted with supply pressures up to 18.3 bars and speeds up to 16,000 rpm. Seal back pressure was controlled to provide four pressure ratios at all supply pressures. No measurable difference in leakage was detected for the seal with and without the swirl brakes. Comparisons of the measurement results for the seal without a swirl brake with the Scharrer theory showed that the theory can be used only to provide design guidelines; systematic differences were observed between theory and experiment due to changes in running speed, supply pressure, and pressure ratio.

Microradiographic investigations on experimentally provoked structural alterations in hard tooth tissues after sealing with plastic material in places where caries is apt to develop

International Nuclear Information System (INIS)

Falten, E.

1981-01-01

The aim of the present investigation was, after sealing three areas in extracted human teeth: fissures, dental necksand approximate areas and subsequent exposure to experimentally produced cariogenous noxae, to establish possible alterations in the area of transition between sealed and unsealed dental enamal. This would provide a further decision-taking aid with regard to the question whether also the remaining parts where caries is apt to develop should be sealed. (orig./MG) [de

Fog seal guidelines.

Science.gov (United States)

2003-10-01

Fog seals are a method of adding asphalt to an existing pavement surface to improve sealing or waterproofing, prevent further stone loss by holding aggregate in place, or simply improve the surface appearance. However, inappropriate use can result in...

Reactor vessel sealing plug

International Nuclear Information System (INIS)

Dooley, R.A.

1986-01-01

An apparatus is described for sealing a cold leg nozzle of a nuclear reactor pressure vessel from a remote location comprising: at least one sealing plug for mechanically sealing the nozzle from the inside of the reactor pressure vessel. The sealing plug includes a plate and a cone assembly having an end part receptive in the nozzle, the plate being axially moveable relative to the cone assembly. The plate and cone assembly have confronting bevelled edges defining an opening therebetween. A primary O-ring is disposed about the opening and is supported on the bevelled edges, the plate being guidably mounted to the cone assembly for movement toward the cone assembly to radially expand the primary O-ring into sealing engagement with the nozzle. A means is included for providing relative movement between the outer plate and the cone assembly

SCISEAL: A CFD Code for Analysis of Fluid Dynamic Forces in Seals

Science.gov (United States)

Althavale, Mahesh M.; Ho, Yin-Hsing; Przekwas, Andre J.

1996-01-01

A 3D CFD code, SCISEAL, has been developed and validated. Its capabilities include cylindrical seals, and it is employed on labyrinth seals, rim seals, and disc cavities. State-of-the-art numerical methods include colocated grids, high-order differencing, and turbulence models which account for wall roughness. SCISEAL computes efficient solutions for complicated flow geometries and seal-specific capabilities (rotor loads, torques, etc.).

Task 4 supporting technology. Part 2: Detailed test plan for thermal seals. Thermal seals evaluation, improvement and test. CAN8-1, Reusable Launch Vehicle (RLV), advanced technology demonstrator: X-33. Leading edge and seals thermal protection system technology demonstration

Science.gov (United States)

Hogenson, P. A.; Lu, Tina

1995-01-01

The objective is to develop the advanced thermal seals to a technology readiness level (TRL) of 6 to support the rapid turnaround time and low maintenance requirements of the X-33 and the future reusable launch vehicle (RLV). This program is divided into three subtasks: (1) orbiter thermal seals operation history review; (2) material, process, and design improvement; and (3) fabrication and evaluation of the advanced thermal seals.

An Automatic Assembling System for Sealing Rings Based on Machine Vision

Directory of Open Access Journals (Sweden)

Mingyu Gao

2017-01-01

Full Text Available In order to grab and place the sealing rings of battery lid quickly and accurately, an automatic assembling system for sealing rings based on machine vision is developed in this paper. The whole system is composed of the light sources, cameras, industrial control units, and a 4-degree-of-freedom industrial robot. Specifically, the sealing rings are recognized and located automatically with the machine vision module. Then industrial robot is controlled for grabbing the sealing rings dynamically under the joint work of multiple control units and visual feedback. Furthermore, the coordinates of the fast-moving battery lid are tracked by the machine vision module. Finally the sealing rings are placed on the sealing ports of battery lid accurately and automatically. Experimental results demonstrate that the proposed system can grab the sealing rings and place them on the sealing port of the fast-moving battery lid successfully. More importantly, the proposed system can improve the efficiency of the battery production line obviously.

A coupled mechanical/hydrologic model for WIPP shaft seals

International Nuclear Information System (INIS)

Ehgartner, B.

1991-06-01

Effective sealing of the Waste Isolation Pilot Plant (WIPP) shafts will be required to isolate defense-generated transuranic wastes from the accessible environment. Shafts penetrate water-bearing hard rock formations before entering a massive creeping-salt formation (Salado) where the WIPP is located. Short and long-term seals are planned for the shafts. Short-term seals, a composite of concrete and bentonite, will primarily be located in the hard rock formations separating the water-bearing zones from the Salado Formation. These seals will limit water flow to the underlying long-term seals in the Salado. The long-term seals will consist of lengthly segments of initially unsaturated crushed salt. Creep closure of the shaft will consolidate unsaturated crushed salt, thereby reducing its permeability. However, water passing through the upper short-term seals and brine inherent to the salt host rock itself will eventually saturate the crushed salt and consolidation could be inhibited. Before saturating, portions of the crushed salt in the shafts are expected to consolidate to a permeability equivalent to the salt host rock, thereby effectively isolating the waste from the overlying water-bearing formations. A phenomenological model is developed for the coupled mechanical/hydrologic behavior of sealed WIPP shafts. The model couples creep closure of the shaft, crushed salt consolidation, and the associated reduction in permeability with Darcy's law for saturated fluid flow to predict the overall permeability of the shaft seal system with time. 17 refs., 6 figs., 1 tab

Fukushima derived radiocesium in subsistence-consumed northern fur seal and wild celery

International Nuclear Information System (INIS)

Ruedig, Elizabeth; Duncan, Colleen; Dickerson, Bobette; Williams, Michael; Gelatt, Thomas; Bell, Justin; Johnson, Thomas E.

2016-01-01

In July 2014, our investigative team traveled to St. Paul Island, Alaska to measure concentrations of radiocesium in wild-caught food products, primarily northern fur seal (Callorhinus ursinus). The 2011 Fukushima Daiichi Nuclear Power Plant accident released radiocesium into the atmosphere and into the western Pacific Ocean; other investigators have detected Fukushima-derived radionuclides in a variety of marine products harvested off the western coast of North America. We tested two subsistence-consumed food products from St. Paul Island, Alaska for Fukushima-derived radionuclides: 54 northern fur seal, and nine putchki (wild celery, Angelica lucida) plants. Individual northern fur seal samples were below minimum detectable activity concentrations of "1"3"7Cs and "1"3"4Cs, but when composited, northern fur seal tissues tested positive for trace quantities of both isotopes. Radiocesium was detected at an activity concentration of 37.2 mBq "1"3"4Cs kg"−"1 f.w. (95% CI: 35.9–38.5) and 141.2 mBq "1"3"7Cs kg"−"1 f.w. (95% CI: 135.5–146.8). The measured isotopic ratio, decay-corrected to the date of harvest, was 0.26 (95% CI: 0.25–0.28). The Fukushima nuclear accident released "1"3"4Cs and "1"3"7Cs in roughly equal quantities, but by the date of harvest in July 2014, this ratio was 0.2774, indicating that this population of seals has been exposed to small quantities of Fukushima-derived radiocesium. Activity concentrations of both "1"3"4Cs and "1"3"7Cs in putchki were below detection limits, even for composited samples. Northern fur seal is known to migrate between coastal Alaska and Japan and the trace "1"3"4Cs in northern fur seal tissue suggests that the population under study had been minimally exposed Fukushima-derived radionuclides. Despite this inference, the radionuclide quantities detected are small and no impact is expected as a result of the measured radiation exposure, either in northern fur seal or human populations consuming this species

Borehole sealing literature review of performance requirements and materials

International Nuclear Information System (INIS)

Piccinin, D.; Hooton, R.D.

1985-02-01

To ensure the safe disposal of nuclear wastes, all potential pathways for radionuclide release to the biosphere must be effectively sealed. This report presents a summary of the literature up to August 1982 and outlines the placement, mechanical property and durability-stability requirements for borehole sealing. An outline of the materials that have been considered for possible use in borehole sealing is also included. Cement grouts are recommended for further study since it is indicated in the literature that cement grouts offer the best opportunity of effectively sealing boreholes employing present technology. However, new and less well known materials should also be researched to ensure that the best possible borehole plugging system is developed. 78 refs

A field trail for sealing abandoned mine shafts and adits with lightweight concrete

International Nuclear Information System (INIS)

Skinner, E.H.; Beckett, L.A.

1994-01-01

An abandoned mine shaft near Omar, in Logan County, WV, was permanently sealed through a cooperative agreement between the West Virginia Department of Commerce, Labor, and Environmental Resources, Division of Environmental Protection, and the US Bureau of Mines (USBM), Abandoned Mine Lands (AML) Program. An engineered shaft seal design was developed and demonstrated that featured lightweight concrete as a key material component at a wet density of about 45 lb/ft 3 . A reinforced concrete cap designed for 5 psi live load was placed over the shaft seal. Applicable new concrete technologies relating to a 100-yr design life were utilized to assure future integrity of the shaft seal. Waterproofing methods were included in the shaft seal design to provide protection from ambient moisture and corrosive mine waters and to increase the long-term durability of the shaft seal. All construction methods used in the field trial are fully adaptable for the mine-reclamation contractor. The USBM research objectives were to develop a broad generic design that will be widely applicable to other adit-sealing and shaft-sealing problems throughout the mining industry

30 CFR 816.14 - Casing and sealing of drilled holes: Temporary.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Casing and sealing of drilled holes: Temporary. 816.14 Section 816.14 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT...-SURFACE MINING ACTIVITIES § 816.14 Casing and sealing of drilled holes: Temporary. Each exploration hole...

Shaft Seal Compensates for Cold Flow

Science.gov (United States)

Myers, W. N.; Hein, L. A.

1985-01-01

Seal components easy to install. Ring seal for rotating or reciprocating shafts spring-loaded to compensate for slow yielding (cold flow) of sealing material. New seal relatively easy to install because components preassembled, then installed in one piece.

Main-coolant-pump shaft-seal guidelines. Volume 2. Operational guidelines. Final report

International Nuclear Information System (INIS)

Fair, C.E.; Greer, A.O.

1983-03-01

This report presents a set of guidelines and criteria for improving main coolant pump shaft seal operational reliability. The noted guidelines are developed from EPRI sponsored nuclear power plant seal operating experience studies. Usage procedures/practices and operational environment influence on seal life and reliability from the most recent such survey are summarized. The shaft seal and its auxiliary supporting systems are discussed both from technical and operational related viewpoints

Film riding seals for rotary machines

Science.gov (United States)

Bidkar, Rahul Anil; Sarawate, Neelesh Nandkumar; Wolfe, Christopher Edward; Ruggiero, Eric John; Raj Mohan, Vivek Raja

2017-03-07

A seal assembly for a rotary machine is provided. The seal assembly includes multiple sealing device segments disposed circumferentially intermediate to a stationary housing and a rotor. Each of the segments includes a shoe plate with a forward-shoe section and an aft-shoe section having one or more labyrinth teeth therebetween facing the rotor. The sealing device includes a stator interface element having a groove or slot for allowing disposal of a spline seal for preventing segment leakages. The sealing device segment also includes multiple bellow springs or flexures connected to the shoe plate and to the stator interface element. Further, the sealing device segments include a secondary seal integrated with the stator interface element at one end and positioned about the multiple bellow springs or flexures and the shoe plate at the other end.

Environmental contaminants in the food chain, NWS Seal Beach and Seal Beach NWR

Energy Technology Data Exchange (ETDEWEB)

Ohlendorf, H.M.; Byron, E.R. [CH2M Hill, Sacramento, CA (United States); Freas, K.E. [CH2M Hill, San Jose, CA (United States); Casados, E.M.; Kidwell, J.J. [Naval Facilities Engineering Command, San Diego, CA (United States). SW Division

1994-12-31

The authors conducted a study to determine whether environmental contaminants occurred in fish and invertebrates at concentrations that could be harmful to birds feeding in the estuarine salt marsh at Seal Beach National Wildlife Refuge (NWR), which is part of Naval Weapons Station (NWS) Seal Beach. Management of the refuge is focused primarily on endangered species, especially the light-footed clapper rail and the California least tern. Important food-chain organisms taken by rails (e.g., crabs and snails) and least terns (small fish) were sampled and analyzed for inorganic and organic contaminants that might be related to Navy activities at the Station. Results indicated that those contaminants are not likely to have lethal effects on rails or terns, although some chemicals (including cadmium, chromium, copper, lead, zinc and DDE) occurred at elevated concentrations in portions of the marsh. Possible sublethal effects also were evaluated and will be discussed.

Advanced Seal Sessions I and II

Science.gov (United States)

Steinetz, Bruce M.; Dunlap, Patrick H.; Sarawate, Neelesh

2013-01-01

As aircraft operators continue to seek higher fuel efficiency, lower emissions, and longer on-wing performance, turbine engine designers are scrutinizing all components for areas of improvement. To achieve overall goals, turbine pressure ratios and by-pass ratios continue to climb. Also, designers are seeking to minimize parasitic and cooling flows to extract the most useful work out of the flow stream, placing a renewed interest on seal technology and secondary flow path management. In the area of future manned spacecraft, advancements are being examined for both habitat seals and re-entry thermal protection system thermal barrierseals. For long duration space craft, designers are continuing to look for savings in parasitic losses to reduce the amount of cabin re-supply air that needs to be brought along. This is placing greater demands on seal designs and materials to exhibit low leakage and be resistant to space environments. For future missions to and from distant planets, the re-entry heating will be higher than for low-earth orbit or lunar return motivating advanced thermal barrier development. This presentation will provide an overview of the seal challenges and opportunities in these diverse areas.

Prolonged fasting increases glutathione biosynthesis in postweaned northern elephant seals

Science.gov (United States)

Vázquez-Medina, José Pablo; Zenteno-Savín, Tania; Forman, Henry Jay; Crocker, Daniel E.; Ortiz, Rudy M.

2011-01-01

SUMMARY Northern elephant seals experience prolonged periods of absolute food and water deprivation (fasting) while breeding, molting or weaning. The postweaning fast in elephant seals is characterized by increases in the renin–angiotensin system, expression of the oxidant-producing protein Nox4, and NADPH oxidase activity; however, these increases are not correlated with increased oxidative damage or inflammation. Glutathione (GSH) is a potent reductant and a cofactor for glutathione peroxidases (GPx), glutathione-S transferases (GST) and 1-cys peroxiredoxin (PrxVI) and thus contributes to the removal of hydroperoxides, preventing oxidative damage. The effects of prolonged food deprivation on the GSH system are not well described in mammals. To test our hypothesis that GSH biosynthesis increases with fasting in postweaned elephant seals, we measured circulating and muscle GSH content at the early and late phases of the postweaning fast in elephant seals along with the activity/protein content of glutamate-cysteine ligase [GCL; catalytic (GCLc) and modulatory (GCLm) subunits], γ-glutamyl transpeptidase (GGT), glutathione disulphide reductase (GR), glucose-6-phosphate dehydrogenase (G6PDH), GST and PrxVI, as well as plasma changes in γ-glutamyl amino acids, glutamate and glutamine. GSH increased two- to four-fold with fasting along with a 40–50% increase in the content of GCLm and GCLc, a 75% increase in GGT activity, a two- to 2.5-fold increase in GR, G6PDH and GST activities and a 30% increase in PrxVI content. Plasma γ-glutamyl glutamine, γ-glutamyl isoleucine and γ-glutamyl methionine also increased with fasting whereas glutamate and glutamine decreased. Results indicate that GSH biosynthesis increases with fasting and that GSH contributes to counteracting hydroperoxide production, preventing oxidative damage in fasting seals. PMID:21430206

HMSRP Hawaiian Monk Seal Fisheries Interactions data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The data set contains records of all documented hookings and/or entanglements of Hawaiian monk seals with actively fished gear, both commercial and recreational. The...

Refrigeration system with clearance seals

International Nuclear Information System (INIS)

Holland, N. J.

1985-01-01

In a refrigeration system such as a split Stirling system, fluid seals associated with the reciprocating displacer are virtually dragless clearance seals. Movement of the displacer relative to the pressure variations in the working volume of gas is retarded by a discrete braking element. Because it is not necessary that the brake providing any sealing action, the brake can be designed for greater durability and less dependence on ambient and operating temperatures. Similarly, the clearance seal can be formed of elements having low thermal expansion such that the seal is not temperature dependent. In the primary embodiments the braking element is a split friction brake

Reactor cavity seal ring

International Nuclear Information System (INIS)

Hankinson, M.F.

1986-01-01

A hydrostatic seal is described for sealing an annular gap between two flat substantially horizontal coplanar surfaces comprising, in combination: a generally flat annular plate of a width sufficient to span a gap between two surfaces: compressible annular sealing means disposed on the bottom surface of the flat annular plate for sealingly engaging the two flat surfaces in response to a downward force exerted on the plate; and fastening means, distributed along the center line of the plate, for releasably fastening the plate in a position to span the gap to be sealed and exert a downward force on the plate, each fastening means including a pair of elongated members of a size to fit into the gap to be sealed, means for mounting the members on the bottom surface of the plate so that at least a portion of each member is radially moveable in a direction toward a respective one of the vertical side surfaces defining the gap to be sealed to engage same and so that the plate is moveable relative to the members in a downward direction in response to hydrostatic pressure applied to the upper surface of the plate when the members are engaging the vertical side surfaces of an annular gap, and an actuating means, mounted on the plate for movement therewith in response to hydrostatic pressure, for radially moving the members, the actuating means extending through a bore in the plate to the upper surface of the plate

30 CFR 816.15 - Casing and sealing of drilled holes: Permanent.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Casing and sealing of drilled holes: Permanent...-SURFACE MINING ACTIVITIES § 816.15 Casing and sealing of drilled holes: Permanent. When no longer needed... exploration hole, other drilled hole or borehole, well, and other exposed underground opening shall be capped...

Automated Image Acquisition System for the Verification of Copper-Brass Seal Images

International Nuclear Information System (INIS)

Stringa, E.; Bergonzi, C.; Littmann, F.; ); Marszalek, Y.; Tempesta, S.; )

2015-01-01

This paper describes a system for the verification of copper-brass seals realized by JRC according to DG ENER requirements. DG ENER processes about 20,000 metal seals per year. The verification of metal seals consists in visually checking the identity of a removed seal. The identity of a copper-brass seal is defined by a random stain pattern realized by the seal producer together with random scratches engraved when the seals are initialized ('seal production'). In order to verify that the seal returned from the field is the expected one its pattern is compared with an image taken during seal production. Formerly, seal initialization and verification were very heavy tasks as seal pictures were acquired with a camera one by one both in the initialization and verification stages. During the initialization the Nuclear Safeguards technicians had to place one by one new seals under a camera and acquire the related reference images. During the verification, the technician had to take used seals and place them one by one under a camera to take new pictures. The new images were presented to the technicians without any preprocessing and the technicians had to recognize the seal. The new station described in this paper has an automated image acquisition system allowing to easily process seals in batches of 100 seals. To simplify the verification, a software automatically centres and rotates the newly acquired seal image in order to perfectly overlap with the reference image acquired during the production phase. The new system significantly speeds up seal production and helps particularly with the demanding task of seal verification. As a large part of the seals is dealt with by a joint Euratom-IAEA team, the IAEA directly profits from this development. The new tool has been in routine use since mid 2013. (author)

Design considerations for mechanical face seals

Science.gov (United States)

Ludwig, L. P.; Greiner, H. F.

1980-01-01

Two companion reports deal with design considerations for improving performance of mechanical face seals, one of family of devices used in general area of fluid sealing of rotating shafts. One report deals with basic seal configuration and other with lubrication of seal.

Engineering report. Part 1: NASA wheel air seal development for space shuttle type environmental requirements

Science.gov (United States)

1973-01-01

The sealing techniques are studied for existing aircraft wheel-tire designs to meet the hard vacuum .00001 torr and cold temperature -65 F requirements of space travel. The investigation covers the use of existing wheel seal designs.

Sealed Radioactive Sources. Information, Resources, and Advice for Key Groups about Preventing the Loss of Control over Sealed Radioactive Sources

International Nuclear Information System (INIS)

2013-10-01

Among its many activities to improve the safety and security of sealed sources, the IAEA has been investigating the root causes of major accidents and incidents since the 1980's and publishes findings so that others can learn from them. There are growing concerns today about the possibility that an improperly stored source could be stolen and used for malicious purposes. To improve both safety and security, information needs to be in the hands of those whose actions and decisions can prevent a source from being lost or stolen in the first place. The IAEA developed this booklet to help improve communication with key groups about hazards that may result from the loss of control over sealed radioactive sources and measures that should be implemented to prevent such loss of control. Many people may benefit from the information contained in this booklet, particularly those working with sources and those likely to be involved if control over a source is lost; especially: officials in government agencies, first responders, medical users, industrial users and the metal recycling industry. The general public may also benefit from an understanding of the fundamentals of radiation safety. This booklet is comprised of several stand-alone chapters intended to communicate with these key groups. Various accidents that are described and information that is provided are relevant to more than one key group and therefore, some information is repeated throughout the booklet. This booklet seeks to raise awareness of the importance of the safety and security of sealed radioactive sources. However, it is not intended to be a comprehensive 'how to' guide for implementing safety and security measures for sealed radioactive sources. For more information on these measures, readers are encouraged to consult the key IAEA safety and security-related publications identified in this booklet

Change of physical activity of the grey seal when exposed to the magnetic field with frequencies of 2, 18 and 36 Hz for 1–4 hours

Directory of Open Access Journals (Sweden)

Yakovlev A. P.

2017-06-01

Full Text Available The results of studies of motor activity of the grey seal when exposed to magnetic fields with frequencies equal to 2, 18 and 36 Hz for 1–4 hours have been presented. The data have been obtained using the methods of continuous logging and registration of certain behavioral manifestations. As the evaluation parameter of motor activity of seals the estimated ratio of emersions per minute has been selected. It has been shown that depending on the frequency of the generated magnetic fields and duration of exposure in this animal, the motor activity of the seal can both be oppressed and increased significantly. The influence of the magnetic field with the frequency of 2 Hz on grey seal for 1–4 hours causes an increase in motor activity of the animal during the period of its exposure; before and after the exposure to MP the number of acts of emersions has been much lower. The effect of MP with the frequency of 18 Hz depends on its duration on the animal: exposure for 1–2 hours causes an increase in motor activity of the seal as during the impact, and at its termination; more prolonged exposure (3–4 hours causes a decrease in motor activity in the period of MP impact and a sharp increase in acts of emersions after the termination of MP generation. The influence of the magnetic field with the frequency of 36 Hz depends on the duration of its effects on the animal: the exposure over 1 hour causes a reduction in motor activity during the MP exposure and after the cessation of its effects; longer exposure (2–4 hours causes a rise in the number of acts of emersions as during the MP generation and after termination of its impact on the animal. Experiments with the "imaginary effect" confirm the validity of the obtained data as during all four experiences some significant fluctuation of animal motor activity has been observed.

Identification of ciguatoxins in Hawaiian monk seals Monachus schauinslandi from the Northwestern and Main Hawaiian Islands.

Science.gov (United States)

Bottein, Marie-Yasmine Dechraoui; Kashinsky, Lizabeth; Wang, Zhihong; Littnan, Charles; Ramsdell, John S

2011-06-15

Ciguatoxins are potent algal neurotoxins that concentrate in fish preyed upon by the critically endangered Hawaiian monk seal (Monachus schauinslandi). The only report for Hawaiian monk seal exposure to ciguatoxins occurred during a 1978 mortality event when two seal liver extracts tested positive by mouse bioassay. Ciguatoxins were thus proposed as a potential threat to the Hawaiian monk seal population. To reinvestigate monk seal exposure to ciguatoxins we utilized more selective detection methods, the Neuro-2A cytotoxicity assay, to quantify ciguatoxin activity and an analytical method LC-MS/MS to confirm the molecular structure. Tissue analysis from dead stranded animals revealed ciguatoxin activity in brain, liver, and muscle, whereas analysis of blood samples from 55 free-ranging animals revealed detectable levels of ciguatoxin activity (0.43 to 5.49 pg/mL P-CTX-1 equiv) in 19% of the animals. Bioassay-guided LC fractionation of two monk seal liver extracts identified several ciguatoxin-like peaks of activity including a peak corresponding to the P-CTX-3C which was confirmed present by LC-MS/MS. In conclusion, this work provides first confirmation that Hawaiian monk seals are exposed to significant levels of ciguatoxins and first evidence of transfer of ciguatoxin to marine mammals. This threat could pose management challenges for this endangered marine mammal species.

Seal monitoring and evaluation for the Gemini offshore windpark: Pre-construction, T0 - 2014 report

NARCIS (Netherlands)

Brasseur, S.M.J.M.; Kirkwood, R.J.

2015-01-01

Two species of seals live in Dutch waters: the grey seal (Halichoerus grypus) and the harbour seal (Phoca vitulina). Although hauling out on near-shore tidal sandbanks, both species forage predominantly in the North Sea. Anthropogenic activities within the North Sea have the potential to overlap

Main-coolant-pump shaft-seal guidelines. Volume 3. Specification guidelines. Final report

International Nuclear Information System (INIS)

Fair, C.E.; Greer, A.O.

1983-03-01

This report presents a set of guidelines and criteria to aid in the generation of procurement specifications for Main Coolant Pump Shaft Seals. The noted guidelines are developed from EPRI sponsored nuclear power plant seal operating experience studies, a review of pump and shaft seal literature and discussions with pump and seal designers. This report is preliminary in nature and could be expanded and finalized subsequent to completion of further design, test and evaluation efforts

Materials for water pump mechanical seals

International Nuclear Information System (INIS)

Brousse, P.

1992-01-01

In view of the continually increasing power ratings of conventional and nuclear power plants and the related reliability and safety problems, plant builders have had to develop seal systems compatible with current water pump performances. In 1970, EDF/R and DD was already concerned by this problem. It soon became obvious that the nature of the materials used for the friction surfaces was decisive for seal durability. Exceptional loads (transients, high vibration levels, etc...) hasten aging. To begin with, friction surfaces consisted of a hard material (tungsten carbide) mated with a soft material (carbon). Resistance was unpredictable and not compatible with industrial requirements. Tests performed on the EDF/R and DD test benches evidenced the same types of degradation. The mechanical seal manufacturers then began to use ceramic materials (silicon carbide), which raised high expectations. Unfortunately, these were recent materials and their manufacturing process was not thoroughly understood. Hopes were soon dashed in many applications, including that of mechanical seals. Fluctuating results were obtained over the next few years. The raw material suppliers made progress, especially with regard to reducing fragility. On a parallel, the mechanical seal manufacturers initiated comparative tests on the friction resistance of materials. It has also been established that ceramics have to be stringently supervised at all levels: part design, inspection, assembly, use. EDF has much insisted that mechanical seal suppliers guarantee the constant quality of their products. EDF/R and DD has systematically tested new sensitive devices, under normal and exceptional conditions, prior to their installation at the plants. At the present time, the silicon carbides proposed by the mechanical seal suppliers are entirely satisfactory. The carbon mating surface was far less problematic. The required reliability was obtained by replacing resin binder carbons by the more resistant

EBR-II rotating plug seal maintenance

International Nuclear Information System (INIS)

Allen, K.J.

1986-01-01

The EBR-II rotating plug seals require frequent cleaning and maintenance to keep the plugs from sticking during fuel handling. Time consuming cleaning on the cover gas and air sides of the dip ring seal is required to remove oxidation and sodium reaction products that accumulate and stop plug rotation. Despite severely limited access, effective seal cleaning techniques have removed 11 800 lb (5 352 kg) of deposits from the seals since 1964. Temperature control modifications and repairs have also required major maintenance work. Suggested seal design recommendations could significantly reduce maintenance on future similar seals

Status of borehole plugging and shaft sealing for geologic isolation of radioactive waste

International Nuclear Information System (INIS)

1979-01-01

Activities in programs devoted to disposal of radioactive waste in deep geologic formations are reported. Research on borehole plugging and shaft sealing is emphasized. Past and current activities related to penetration sealing were assessed through an exhaustive literature review and contacts with industrial, governmental, and research organizations. Cited references are included along with a bibliography assembled for this study. Evaluation of literature reviewed and presentation of information obtained from personal contacts are summarized. Technical considerations for penetration sealing as related to nuclear waste isolation, but which may differ from conventional technology, are presented and research needs are identified

Sealing of ceramic SOFC-components with glass seals; Fuegen von keramischen Komponenten der Hochtemperatur-Brennstoffzellen mittels Glas- und Glaskeramikloten

Energy Technology Data Exchange (ETDEWEB)

Schillig, Cora

2012-07-10

The solid oxide fuel cell (SOFC) converts chemical energy of a fuel directly into electrical energy. However, for the implementation of SOFC-technology in competition to conventional power plants costs have to be reduced. The use of an alternative tubular cell design without closed end would allow reducing costs during cell manufacturing. However, this change in design makes a gastight sealing inside the generator near the gas inlet necessary. Different ceramic materials with varying coefficients of thermal expansion have to be sealed gastight and electrical insulating at temperatures between 850 C and 1000 C to prevent the gases from mixing and an electrical shortcut between the cells. This work comprises analysis of commercially available glass and glass-ceramic systems manufactured by Schott Electronic Packaging, Areva T and D and Ferro Corporation. Additionally new developed sealing glass and glass-ceramic systems were investigated and all systems were characterized fundamentally for the use as sealing material in SOFC generators. Therefore different test assemblies and series were conducted. Essential characteristics of a suitable sealing system are a thermal expansion coefficient between 9,5 and 12 . 10{sup -6}K{sup -1}, a viscosity in the range between 10{sup 4} to 10{sup 6} dPa{sup *}s and a wetting angle smaller than 90 during the sealing process. Also unwanted chemical side reactions between the sealing partners must be prevented, because a change in the phase composition or the creation of new phases in the sealing material could endanger the stability of the seal. Heat cycles, particularly those during generator operation, cause deterioration of the sealing material and subsequent reduction in its ability to prevent mixing of the gases. Sealant leaks can drastically impact efficiency of the generator. In order to ensure optimum operation low leak rates around 2,3 . 10{sup -4} mbar l/sec/cm{sup 2} must be maintained. Especially glass and glass

Coaxial twin-shaft magnetic fluid seals applied in vacuum wafer-handling robot

Science.gov (United States)

Cong, Ming; Wen, Haiying; Du, Yu; Dai, Penglei

2012-07-01

Compared with traditional mechanical seals, magnetic fluid seals have unique characters of high airtightness, minimal friction torque requirements, pollution-free and long life-span, widely used in vacuum robots. With the rapid development of Integrate Circuit (IC), there is a stringent requirement for sealing wafer-handling robots when working in a vacuum environment. The parameters of magnetic fluid seals structure is very important in the vacuum robot design. This paper gives a magnetic fluid seal device for the robot. Firstly, the seal differential pressure formulas of magnetic fluid seal are deduced according to the theory of ferrohydrodynamics, which indicate that the magnetic field gradient in the sealing gap determines the seal capacity of magnetic fluid seal. Secondly, the magnetic analysis model of twin-shaft magnetic fluid seals structure is established. By analyzing the magnetic field distribution of dual magnetic fluid seal, the optimal value ranges of important parameters, including parameters of the permanent magnetic ring, the magnetic pole tooth, the outer shaft, the outer shaft sleeve and the axial relative position of two permanent magnetic rings, which affect the seal differential pressure, are obtained. A wafer-handling robot equipped with coaxial twin-shaft magnetic fluid rotary seals and bellows seal is devised and an optimized twin-shaft magnetic fluid seals experimental platform is built. Test result shows that when the speed of the two rotational shafts ranges from 0-500 r/min, the maximum burst pressure is about 0.24 MPa. Magnetic fluid rotary seals can provide satisfactory performance in the application of wafer-handling robot. The proposed coaxial twin-shaft magnetic fluid rotary seal provides the instruction to design high-speed vacuum robot.

Air riding seal with purge cavity

Science.gov (United States)

Sexton, Thomas D; Mills, Jacob A

2017-08-15

An air riding seal for a turbine in a gas turbine engine, where an annular piston is axial moveable within an annular piston chamber formed in a stator of the turbine and forms a seal with a surface on the rotor using pressurized air that forms a cushion in a pocket of the annular piston. A purge cavity is formed on the annular piston and is connected to a purge hole that extends through the annular piston to a lower pressure region around the annular piston or through the rotor to an opposite side. The annular piston is sealed also with inner and outer seals that can be a labyrinth seal to form an additional seal than the cushion of air in the pocket to prevent the face of the air riding seal from overheating.

Characteristics of the excavation response zone as applied to shaft sealing

International Nuclear Information System (INIS)

Jakubick, A.T.; Klein, R.; Gray, M.N.; Keil, L.D.

1989-01-01

Effective sealing of an underground repository requires high quality seals. Clay-based backfills in combination with cement plugs are the possible candidates. An important component of the shaft sealing program is the development of techniques to predict and monitor the flow in the excavation response zone (ERZ) and at the seal-rock interface. The mechanical and hydraulic performance of the seal and backfill and the flow characteristics of the ERZ under in situ conditions will be tested in three experimental shafts to be excavated in the URL. The use of the vacuum permeability technique for characterization of the hydraulic properties and of the permeability distribution in the ERZ under various geomechanical conditions is discussed

Seals in nuclear reactors

International Nuclear Information System (INIS)

1979-01-01

The aim of this invention is the provision of improved seals for reactor vessels in which fuel assemblies are located together with inlets and outlets for the circulation of a coolant. The object is to provide a seal arrangement for the rotatable plugs of nuclear reactor closure heads which has good sealing capacities over a wide gap during operation of the reactor but which also permits uninhibited rotation of the plugs for maintenance. (U.K.)

Self-acting and hydrodynamic shaft seals

Science.gov (United States)

Ludwig, L. P.

1973-01-01

Self-acting and hydrodynamic seals are described. The analytical procedures are outlined for obtaining a seal force balance and the operating film thickness. Particular attention is given to primary ring response (seal vibration) to rotating seat face runout. This response analysis revealed three different vibration modes. Proposed applications of self-acting seals in gas turbine engines and in rocket vehicle turbopumps are described. Also experimental data on self-acting face seals operating under simulated gas turbine conditions are given; these data show the feasibility of operating the seal at conditions of 345 newtons per square centimeter (500 psi) and 152 meters per second (500 ft/sec) sliding speed.

Radial lip seals, thermal aspects

NARCIS (Netherlands)

Stakenborg, M.J.L.; van Ostaijen, R.A.J.; Dowson, D.

1989-01-01

In this paper the influence of temperature on tne seal-snarc contact is studied, using coupled temperature-stress FEH analysis. A thermal network model is used to calculate the seal-shaft contact temperature for steady-state and transient conditions. Contact temperatures were measured under the seal

Airfoil seal system for gas turbine engine

Science.gov (United States)

None, None

2013-06-25

A turbine airfoil seal system of a turbine engine having a seal base with a plurality of seal strips extending therefrom for sealing gaps between rotational airfoils and adjacent stationary components. The seal strips may overlap each other and may be generally aligned with each other. The seal strips may flex during operation to further reduce the gap between the rotational airfoils and adjacent stationary components.

Service life evaluation of non-metallic containment seals

International Nuclear Information System (INIS)

Pringle, T.G.

1994-01-01

A Service Life Evaluation Program (SLEP) was successfully completed for expansion joint seals used in the pressure relief duct of Pickering NGS, an eight unit CANDU station. These seals are part of the containment boundary, are difficult to replace and then only during station outages which are scheduled at ten year intervals. The SLEP, consisting of an accelerated aging program and a qualification test, was undertaken to determine the service life of the seals such that they would be capable of remaining functional following a combination of service life, a design basis accident and a subsequent seismic event. The Arrhenius model of aging was used for the accelerated aging program. Samples of seal material were subjected to oven aging at five temperatures, 150, 160, 170, 180 and 190 deg C. Tensile properties and hardness were measured at various aging times and Arrhenius plots constructed. Based on changes in elongation, activation energies of 1.2 eV and 1.1 eV were calculated for the reinforcing fabric and the silicone cover rubber, respectively. Hardness measurements were also taken but as expected, no precise quantitative aging relationship could be determined from material hardness. For the qualification test a representative length of seal was installed and field-spliced in a test frame built to simulate the installed configuration of the seal. It then underwent accelerated aging equivalent to the service life, followed by LOCA irradiation exposure to LOCA conditions of humidity, temperature and pressure and a design-basis seismic event. Finally, a pressure test to approximately five times design pressure was successfully performed to demonstrate the remaining margin of safety. Periodic air leakage tests indicated no deterioration in sealing performance and no physical deterioration was apparent. (author). 11 refs., 2 tabs., 8 figs

Analysis on the Viscous Pumping in a Magnetic Fluid Seal Under a Rotating Load and the Seal Design

OpenAIRE

長屋, 幸助; 大沼, 浩身; 佐藤, 淳

1990-01-01

This paper discusses effects of viscous pumping in a magnetic fluid seal under a rotating load. The Reynolds equation was presented for the seal based on magnetic fluid mechanics, and the expressions for obtaining pressures in the seal, eccentricities of the rotating shaft due to the viscous pumping and seal pressures were given. Numerical Calculations were carried out for some sample problems, and the effect of magnetic flux densities on the pressure in the seal and the seal pressures were c...

Albinistic common seals (Phoca vitulina) and melanistic grey seals (Halichoerus grypus) rehabilitated in the Netherlands

NARCIS (Netherlands)

Osinga, Nynke; 't Hart, Pieter; Vader, Pieter C. van Voorst

2010-01-01

The Seal Rehabilitation and Research Centre (SRRC) in Pieterburen, The Netherlands, rehabilitates seals from the waters of the Wadden Sea, North Sea and Southwest Delta area. Incidental observations of albinism and melanism in common and grey seals are known from countries surrounding the North Sea.

19 CFR 113.25 - Seals.

Science.gov (United States)

2010-04-01

... signatures of principal and surety, if individuals, and the corporate seal shall be affixed close to the... law of the state in which executed. However, when the charter or governing statute of a corporation requires its acts to be evidenced by its corporate seal, such seal is required. ...

Reduction of Radioactive Waste Through the Reuse and Recycle Policy of the Sealed Radioactive Sources Management

Directory of Open Access Journals (Sweden)

T. Marpaung

2012-08-01

Full Text Available In the past few years, the utilization of sealed source for medical, industrial and research purposes has shown an accelerating increase. This situation will lead to increases in the amount of sealed radioactive. During its use, a sealed radioactive waste will eventually become either a spent sealed source or disused sealed radioactive source (DSRS, due to certain factors. The reduction of the amount of radioactive waste can be executed through the application of reuse and recycle of sealed source. The reuse and recycle policy for spent and disused sealed sources are not already specified yet. The reuse of spent sealed sources can be applied only for the sources which had been used in the medical field for radiotherapy, namely the reuse of a teletherapy Co-60 source in a calibration facility. The recycle of a spent sealed source can be performed for radioactive sources with relatively high activities and long half-lives; however, the recycling activity may only be performed by the manufacturer. To avoid legal conflicts, in the amendment to the Government Regulation No.27 Year 2002 on Management of Radioactive Waste, there will be a recommendation for a new scheme in the management of radioactive waste to facilitate the application of the principles of reduce, reuse, and recycle

Reduction of Radioactive Waste Through the Reuse and Recycle Policy of the Sealed Radioactive Sources Management

International Nuclear Information System (INIS)

Marpaung, T.

2012-01-01

In the past few years, the utilization of sealed source for medical, industrial and research purposes has shown an accelerating increase. This situation will lead to increases in the amount of sealed radioactive. During its use, a sealed radioactive waste will eventually become either a spent sealed source or disused sealed radioactive source (DSRS), due to certain factors. The reduction of the amount of radioactive waste can be executed through the application of reuse and recycle of sealed source. The reuse and recycle policy for spent and disused sealed sources are not already specified yet. The reuse of spent sealed sources can be applied only for the sources which had been used in the medical field for radiotherapy, namely the reuse of a teletherapy Co-60 source in a calibration facility. The recycle of a spent sealed source can be performed for radioactive sources with relatively high activities and long half-lives; however, the recycling activity may only be performed by the manufacturer. To avoid legal conflicts, in the amendment to the Government Regulation No.27 Year 2002 on Management of Radioactive Waste, there will be a recommendation for a new scheme in the management of radioactive waste to facilitate the application of the principles of reduce, reuse, and recycle (author)

Tetraspanin 7 regulates sealing zone formation and the bone-resorbing activity of osteoclasts

Energy Technology Data Exchange (ETDEWEB)

Kwon, Jun-Oh; Lee, Yong Deok; Kim, Haemin; Kim, Min Kyung; Song, Min-Kyoung; Lee, Zang Hee; Kim, Hong-Hee, E-mail: hhbkim@snu.ac.kr

2016-09-02

Tetraspanin family proteins regulate morphology, motility, fusion, and signaling in various cell types. We investigated the role of the tetraspanin 7 (Tspan7) isoform in the differentiation and function of osteoclasts. Tspan7 was up-regulated during osteoclastogenesis. When Tspan7 expression was reduced in primary precursor cells by siRNA-mediated gene knock-down, the generation of multinuclear osteoclasts was not affected. However, a striking cytoskeletal abnormality was observed: the formation of the podosome belt structure was inhibited and the microtubular network were disrupted by Tspan7 knock-down. Decreases in acetylated microtubules and levels of phosphorylated Src and Pyk2 in Tspan7 knock-down cells supported the involvement of Tspan7 in cytoskeletal rearrangement signaling in osteoclasts. This cytoskeletal defect interfered with sealing zone formation and subsequently the bone-resorbing activity of mature osteoclasts on dentin surfaces. Our results suggest that Tspan7 plays an important role in cytoskeletal organization required for the bone-resorbing function of osteoclasts by regulating signaling to Src, Pyk2, and microtubules. - Highlights: • Tspan7 expression is up-regulated during osteoclastogenesis. • Tspan7 regulates podosome belt organization in osteoclasts. • Tspan7 is crucial for sealing zone formation and bone-resorption by osteoclasts. • Src and Pyk2 phosphorylation and microtubule acetylation mediate Tspan7 function.

BOSS: Borehole Disposal of Disused Sealed Sources. A Technical Manual

International Nuclear Information System (INIS)

2011-01-01

The management of disused radioactive sources is the responsibility of individual Member States. Accordingly, interest in technologies to allow the safe, secure and sustainable management of disused sealed radioactive sources is growing. This publication is a technical summary on preparing and planning predisposal and disposal activities with regard to the BOSS (borehole disposal of disused sealed sources) system, a safe, simple and cost effective solution for the management of disused sealed radioactive sources. It advises potential implementers and decision makers on the implementation of BOSS, which is expected to provide Member States with a successful tool to contribute to the safety and security of current and future generations.

Executive summary and general conclusions of the rock sealing project

International Nuclear Information System (INIS)

Pusch, R.

1992-06-01

The Stripa Rock Sealing Project logically followed the two first Stripa research phases dealing with canister-embedment and plugging of excavations in repositories. The major activities in the third phase were: * Literature review and interviews for setting the state of art of rock fracture sealing. * Pilot field and lab testing applying a new effective 'dynamic' grouting technique. * Development of a general grout flow theory. * Investigation of physical properties and longevity of major candidate grouts. * Performance of 4 large-scale tests. The literature study showed that longevity aspects limited the number of potentially useful grout materials to smectitic clay and cement. The pilot testing showed that fine-grained grouts can be effectively injected in relatively fine fractures. The theoretical work led to a general grout flow theory valid both for grouting at a constant, static pressure with non-Newtonian material properties, and for 'dynamic' injection with superimposed oscillations, yielding Newtonian material behavior. The investigation of physical properties of candidate grouts with respect to hydraulic conductivity, shear strength, sensitivity to mechanical strain, as well as to chemical stability, showed that effective sealing is offered, and that any rock can have its bulk conductivity reduced to about 10 -10 m/s. The field tests comprised investigation of excavation-induced disturbance and attempts to seal disturbed rock, and in separate tests, grouting of deposition holes and a natural fine-fracture zone. Considerable disturbance of nearfield rock by blasting and stress changes, yielding an increase in axial hydraulic conductivity by 3 and 1 order of magnitude, respectively, was documented but various factors, primarily debris in the fractures, made grouting of blasted rock ineffective. Narrow fractures in deposition holes and in a natural fracture zone were sealed rather effectively. (au)

Hydraulic Characterization Activities in Support of the Shaft-Seals Fluid-Flow Modeling Integration into the WIPP EPA Compliance Certification Application

International Nuclear Information System (INIS)

Knowles, M.K.; Hurtado, L.D.; Dale, Tim

1997-12-01

The Waste Isolation Pilot Plant (WIPP) is a planned geologic repository for permanent disposal of transuranic waste generated by the U.S. Department of Energy. Disposal regions consist of panels and drifts mined from the bedded salt of the Salado Formation at a depth of approximately 650 m below the surface. This lithology is part of the 225 million year old Delaware Basin, and is geographically located in southeastern New Mexico. Four shafts service the facility needs for air intake, exhaust, waste handling, and salt handling. As the science advisor for the project, Sandia National Laboratories developed the WIPP shaft sealing system design. This design is a fundamental component of the application process for facility licensing, and has been found acceptable by stakeholders and regulatory agencies. The seal system design is founded on results obtained from laboratory and field experiments, numerical modeling, and engineering judgment. This paper describes a field test program to characterize the fluid flow properties in the WIPP shafts at representative seal locations. This work was conducted by Duke Engineering and Services under contract to Sandia National Laboratories in support of the seal system design

Theoretical investigations of grout seal longevity - Final report

International Nuclear Information System (INIS)

Alcorn, S.; Coons, W.; Christian-Frear, T.; Wallace, M.

1992-04-01

Theoretical investigations into the longevity of repository seals have dealt primarily with the development of a methodology to evaluate interactions between portland cement-based grout and groundwater. Evaluation of chemical thermodynamic equilibria between grout and groundwater, and among grout, groundwater, and granitic host rock phases using the geochemical codes EQ3NR/EQ6 suggests that a fracture filled with grout and saturated with groundwater will tend to fill and 'tighten' with time. Results of these investigations suggest that cement grout seals will maintain an acceptable level of performance for tens of thousands to millions of years, provided the repository is sited where groundwater chemistry is compatible with the seals and hydrologic gradients are low. The results of the grout: groundwater: rock calculations suggest that buffering of the fracture seals chemical systems by the granite rock may be important in determining the long-term fate of grout seals and the resulting phase assemblage in the fracture. The similarity of the modelled reaction products to those observed in naturally filled fractures suggests that with time equilibrium will be approached and grouted fractures subject to low hydrologic gradients will continue to seal. If grout injected into fractures materially reduces groundwater flux, the approach to chemical equilibrium will likely be accelerated. In light of this, even very thin or imperfectly grouted fractures would tighten in suitable hydrogeologic environments. (29 refs.) (au)

Upgrading primary heat transport pump seals

International Nuclear Information System (INIS)

Graham, T.; Metcalfe, R.; Rhodes, D.; McInnes, D.

1995-01-01

Changes in the operating environment at the Bruce-A Nuclear Generating Station created the need for an upgraded Primary Heat Transport Pump (PHTP) seal. In particular, the requirement for low pressure running during more frequent start-ups exposed a weakness of the CAN2 seal and reduced its reliability. The primary concern at Bruce-A was the rotation of the CAN2 No. 2 stators in their holders. The introduction of low pressure running exacerbated this problem, giving rapid wear of the stator back face, overheating, and thermocracking. In addition, the resulting increase in friction between the stator and its holder increased stationary-side hysteresis and thereby changed the seal characteristic to the point where interseal pressure oscillations became prevalent. The resultant increased hysteresis also led to hard rubbing of the seal faces during temperature transients. An upgraded seal was required for improved reliability to avoid forced outages and to reduce maintenance costs. This paper describes this upgraded 'replacement seal' and its performance history. In spite of the 'teething' problems detailed in this paper, there have been no forced outages due to the replacement seal, and in the words of a seal maintenance worker at Bruce-A, 'it allows me to go home and sleep at night instead of worrying about seal failures.' (author)

Sealing properties of cement-based grout materials used in the rock sealing project

Energy Technology Data Exchange (ETDEWEB)

Onofrei, M; Gray, M N; Pusch, R; Boergesson, L; Karnland, O; Shenton, B; Walker, B

1993-12-01

The Task Force on Sealing Materials and Techniques of the Stripa Project recommended that work be undertaken to study the sealing properties of cement-based grout materials. A new class of cement-based grouts (high-performance grouts) with the ability to penetrate and seal fine fractures in granite was investigated. The materials were selected for their small mean particle size and the ability to be made fluid by a superplasticizer at low water/cementitious-materials ratios. The fundamental physical and chemical properties (such as the particle size and chemical composition) of the materials were evaluated. The rheological properties of freshly mixed grouts, which control the workability of the grouts, were determined together with the properties of hardened materials, which largely control the long-term performance (longevity) of the materials in repository settings. The materials selected were shown to remain gel-like during the setting period, and so the grouts may be expected to remain largely homogenous during and after injection into the rock without separating into solid and liquid phases. The hydraulic conductivity and strength of hardened grouts were determined. The microstructure of the bulk grouts was characterized by a high degree of homogeneity with extremely fine porosity. The low hydraulic conductivity and good mechanical properties are consistent with the extremely fine porosity. The ability of the fractured grouts to self-seal was also observed in tests in which the hydraulic conductivity of recompacted granulated grouts was determined. The laboratory tests were carried out in parallel with investigations of the in situ performance of the materials and with the development of geochemical and theoretical models for cement-based grout longevity. (author). 56 refs., 15 tabs., 98 figs.

Sealing properties of cement-based grout materials used in the rock sealing project

International Nuclear Information System (INIS)

Onofrei, M.; Gray, M.N.; Pusch, R.; Boergesson, L.; Karnland, O.; Shenton, B.; Walker, B.

1993-12-01

The Task Force on Sealing Materials and Techniques of the Stripa Project recommended that work be undertaken to study the sealing properties of cement-based grout materials. A new class of cement-based grouts (high-performance grouts) with the ability to penetrate and seal fine fractures in granite was investigated. The materials were selected for their small mean particle size and the ability to be made fluid by a superplasticizer at low water/cementitious-materials ratios. The fundamental physical and chemical properties (such as the particle size and chemical composition) of the materials were evaluated. The rheological properties of freshly mixed grouts, which control the workability of the grouts, were determined together with the properties of hardened materials, which largely control the long-term performance (longevity) of the materials in repository settings. The materials selected were shown to remain gel-like during the setting period, and so the grouts may be expected to remain largely homogenous during and after injection into the rock without separating into solid and liquid phases. The hydraulic conductivity and strength of hardened grouts were determined. The microstructure of the bulk grouts was characterized by a high degree of homogeneity with extremely fine porosity. The low hydraulic conductivity and good mechanical properties are consistent with the extremely fine porosity. The ability of the fractured grouts to self-seal was also observed in tests in which the hydraulic conductivity of recompacted granulated grouts was determined. The laboratory tests were carried out in parallel with investigations of the in situ performance of the materials and with the development of geochemical and theoretical models for cement-based grout longevity. (author). 56 refs., 15 tabs., 98 figs

Fiber Optic Safeguards Sealing System

Science.gov (United States)

1978-01-01

8217 or trade names does not constitute an official indorsement or approval of the use thereof. Destroy this report when it is no longer needed. Do not...an intergrity check of a seal than to photograph the seal’s fingerprints and to match positive/negative overlays. The seal identification time and

Development and testing of improved polyimide actuator rod seals at higher temperatures for use in advanced aircraft hydraulic systems

Science.gov (United States)

Robinson, E. D.; Waterman, A. W.; Nelson, W. G.

1972-01-01

Polyimide second stage rod seals were evaluated to determine their suitability for application in advanced aircraft systems. The configurations of the seals are described. The conditions of the life cycle tests are provided. It was determined that external rod seal leakage was within prescribed limits and that the seals showed no signs of structural degradation.

An Experimental Investigation of Leak Rate Performance of a Subscale Candidate Elastomer Docking Space Seal

Science.gov (United States)

Garafolo, Nicholas G.; Daniels, Christopher C.

2011-01-01

A novel docking seal was developed for the main interface seal of NASA s Low Impact Docking System (LIDS). This interface seal was designed to maintain acceptable leak rates while being exposed to the harsh environmental conditions of outer space. In this experimental evaluation, a candidate docking seal assembly called Engineering Development Unit (EDU58) was characterized and evaluated against the Constellation Project leak rate requirement. The EDU58 candidate seal assembly was manufactured from silicone elastomer S0383-70 vacuum molded in a metal retainer ring. Four seal designs were considered with unique characteristic heights. The leak rate performance was characterized through a mass point leak rate method by monitoring gas properties within an internal control volume. The leakage performance of the seals were described herein at representative docking temperatures of -50, +23, and +50 C for all four seal designs. Leak performance was also characterized at 100, 74, and 48 percent of full closure. For all conditions considered, the candidate seal assemblies met the Constellation Project leak rate requirement.

Simulation of the noise transmission through automotive door seals

CERN Document Server

Hazir, Andreas

2016-01-01

Andreas Hazir is investigating the door seal contribution to the interior noise level of production vehicles. These investigations contain experimental contribution analyses of real production vehicles and of academic test cases as well as the development of a simulation methodology for noise transmission through sealing systems and side windows. The simulations are realized by coupling transient computational aeroacoustics of the exterior flow to nonlinear finite element simulations of the structural transmission. By introducing a linear transmission model, the setup and computational costs of the seal noise transmission are significantly reduced, resulting in the feasibility of numerical contribution analyses of real production vehicles. Contents Contribution Analyses of Production Vehicles Acoustic Excitation versus Aeroacoustic Excitation Development of a Simulation Methodology Sensitivity Analysis of Noise Transmission Simulations Target Groups Researchers and students in the field of automotive engineer...

Validation Assessment of a Glass-to-Metal Seal Finite-Element Model

Energy Technology Data Exchange (ETDEWEB)

Jamison, Ryan Dale [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Buchheit, Thomas E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Emery, John M [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Romero, Vicente J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stavig, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Newton, Clay S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brown, Arthur [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-10-01

Sealing glasses are ubiquitous in high pressure and temperature engineering applications, such as hermetic feed-through electrical connectors. A common connector technology are glass-to-metal seals where a metal shell compresses a sealing glass to create a hermetic seal. Though finite-element analysis has been used to understand and design glass-to-metal seals for many years, there has been little validation of these models. An indentation technique was employed to measure the residual stress on the surface of a simple glass-to-metal seal. Recently developed rate- dependent material models of both Schott 8061 and 304L VAR stainless steel have been applied to a finite-element model of the simple glass-to-metal seal. Model predictions of residual stress based on the evolution of material models are shown. These model predictions are compared to measured data. Validity of the finite- element predictions is discussed. It will be shown that the finite-element model of the glass-to-metal seal accurately predicts the mean residual stress in the glass near the glass-to-metal interface and is valid for this quantity of interest.

Effects of Hypervelocity Impacts on Silicone Elastomer Seals and Mating Aluminum Surfaces

Science.gov (United States)

deGroh, Henry C., III; Steinetz, Bruce M.

2009-01-01

While in space silicone based elastomer seals planned for use on NASA's Crew Exploration Vehicle (CEV) are exposed to threats from micrometeoroids and orbital debris (MMOD). An understanding of these threats is required to assess risks to the crew, the CEV orbiter, and missions. An Earth based campaign of hypervelocity impacts on small scale seal rings has been done to help estimate MMOD threats to the primary docking seal being developed for the Low Impact Docking System (LIDS). LIDS is being developed to enable the CEV to dock to the ISS (International Space Station) or to Altair (NASA's next lunar lander). The silicone seal on LIDS seals against aluminum alloy flanges on ISS or Altair. Since the integrity of a seal depends on both sealing surfaces, aluminum targets were also impacted. The variables considered in this study included projectile mass, density, speed, incidence angle, seal materials, and target surface treatments and coatings. Most of the impacts used a velocity near 8 km/s and spherical aluminum projectiles (density = 2.7 g/cubic cm), however, a few tests were done near 5.6 km/s. Tests were also performed using projectile densities of 7.7, 2.79, 2.5 or 1.14 g/cubic cm. Projectile incidence angles examined included 0 deg, 45 deg, and 60 deg from normal to the plane of the target. Elastomer compounds impacted include Parker's S0383-70 and Esterline's ELA-SA-401 in the as received condition, or after an atomic oxygen treatment. Bare, anodized and nickel coated aluminum targets were tested simulating the candidate mating seal surface materials. After impact, seals and aluminum plates were leak tested: damaged seals were tested against an undamaged aluminum plate; and undamaged seals were placed at various locations over craters in aluminum plates. It has been shown that silicone elastomer seals can withstand an impressive level of damage before leaking beyond allowable limits. In general on the tests performed to date, the diameter of the crater in

Elastomer seal for a large toroidal vacuum chamber

International Nuclear Information System (INIS)

Skellett, S.; Casey, F.; Blake, H.

1978-07-01

An aluminium toroidal vacuum chamber for use at 10(-6) torr, whose overall diameter is in the region of 5 metres, was built from 4 component parts which resulted in joint lines in the horizontal and vertical planes crossing each other in 4 places. A viton seal was developed which allows a vacuum tight joint to be made without the need for tightly toleranced fitting of the mating faces and also overcomes the difficulty of ensuring a reliable seal at cross-over joints. Ease of maintenance and repair in situ are important factors of the design. An assembly which presented the geometry of the sealing problem was tested and is described here. Various adhesives for bonding viton were examined for the manufacture of the seal. The most suitable adhesive was found to be Loctite S496, chosen for its bond strength and convenience in use. A device for preparing and bonding the viton in situ is described. (author)

The effectiveness of quantum operations for eavesdropping on sealed messages

International Nuclear Information System (INIS)

Lopata, Paul A; Bahder, Thomas B

2007-01-01

A quantum protocol is described which enables a user to send sealed messages and that allows for the detection of active eavesdroppers. We examine a class of eavesdropping strategies, those that make use of quantum operations, and we determine the information gain versus disturbance caused by these strategies. We demonstrate this tradeoff with an example and we compare this protocol to quantum key distribution, quantum direct communication, and quantum seal protocols

Sealed can of spent fuel

International Nuclear Information System (INIS)

Suzuki, Yasuyuki.

1976-01-01

Object: To provide a seal plug cover with a gripping portion fitted to a canning machine and a gripping portion fitted to a gripper of the same configuration as a fuel body for handling the fuel body so as to facilitate the handling work. Structure: A sealed can comprises a vessel and a seal plug cover, said cover being substantially in the form of a bottomed cylinder, which is slipped on the vessel and air-tightly secured by a fastening bolt between it and a flange. The spent fuel body is received into the vessel together with coolant during the step of canning operation. Said seal plug cover has two gripping portions, one for opening and closing the plug cover of the canning machine as an exclusive use member, the other being in the form of a hook-shaped peripheral groove, whereby the gripping portions may be effectively used using the same gripper when the spent fuel body is transported while being received in the sealed can or when the fuel body is removed from the sealed can. (Kawakami, Y.)

Control and optimization of sealing layer in films

Science.gov (United States)

Najarzadeh, Zahra

Heat sealing is the process to achieve the hermetic closure of a package by applying heat and pressure on two polymer films for a specified dwell time. The heat sealing process has been used in packaging of a wide spectrum of products, in particular for food packaging. During the past two decades, heat sealing machinery has been developed for very high speed line production which requires very precise process condition and material optimization. Heat seal process conditions, including temperature, dwell time, and pressure as well as film characteristics such as molecular weight, molecular weight distribution, long and short chain branching are the key factors that control the final quality of the joint. In the first part of this study, we have investigated the interrelated influence of heat seal process parameters on the strengthening of the interface as well as the micro mechanisms involved. The effects of heat seal temperature, pressure, and dwell time on seal strength of LLDPE were illustrated in "time-temperature" and "pressure-temperature" 3D maps, a methodology that is easily applicable to other systems. The interfacial adhesion of semicrystalline polymers was not well understood. We thus studied the adhesion behaviour of LLDPE as a semicrystalline polymer. The results indicated that the time and temperature dependence of seal strength is a consequence of the fraction of amorphous phase available at the interface of films. The seal strength had a linear correlation with the square root of sealing time which was also supported by the welding models. The slope of this linear correlation increased with temperature. This work was followed concurrently by two main approaches: analysis of polymer chain behaviour from microscopic point of view based on reptation theory and conventional macroscopic analysis based on bulk properties of the polymer. Failure mechanisms and fractured surfaces were also analyzed after peeling. Moreover, the topography and morphology of

Insecurity of imperfect quantum bit seal

International Nuclear Information System (INIS)

Chau, H.F.

2006-01-01

Quantum bit seal is a way to encode a classical bit quantum mechanically so that everyone can obtain non-zero information on the value of the bit. Moreover, such an attempt should have a high chance of being detected by an authorized verifier. Surely, a reader looks for a way to get the maximum amount of information on the sealed bit and at the same time to minimize her chance of being caught. And a verifier picks a sealing scheme that maximizes his chance of detecting any measurement of the sealed bit. Here, I report a strategy that passes all measurement detection procedures at least half of the time for all quantum bit sealing schemes. This strategy also minimizes a reader's chance of being caught under a certain scheme. In this way, I extend the result of Bechmann-Pasquinucci et al. by proving that quantum seal is insecure in the case of imperfect sealed bit recovery

Ultrasonic dip seal maintenance system

International Nuclear Information System (INIS)

Poindexter, A.M.; Ricks, H.E.

1978-01-01

Disclosed is a system for removing impurities from the surfaces of liquid dip seals and for wetting the metal surfaces of liquid dip seals in nuclear components. The system comprises an ultrasonic transducer that transmits ultrasonic vibrations along an ultrasonic probe to the metal and liquid surfaces of the dip seal thereby loosening and removing those impurities

Conceptual design of shaft seals for a nuclear waste disposal vault

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-04-01

The concept of a disposal vault in the Canadian Shield for the effective isolation of nuclear fuel wastes is being assessed as part of the Canadian Nuclear Fuel Waste Management Program. The vault would be accessed from the surface by a number of shafts, which would likely penetrate the vault environment and intersect significant rock fractures and thereby form preferential pathways for the migration of radionuclides from the disposal area to the biosphere. Golder Associates were retained to conduct a conceptual design study of sealing and backfilling the shafts. The first volume of this report reviews current shaft sinking and lining technologies, and recommends the preferred construction methods for the shafts. Factors that could affect the design of a shaft seal system are reviewed, and a conceptual shaft seal is proposed. The second volume addresses the performance assessment of a shaft seal system. While there are no specific performance criteria against which to compare the anticipated containment characteristics of the shaft seal system proposed, the methodology developed for the performance assessment of the reference design should enable the design to be modified to meet performance criteria as they are developed. The report estimates that it will cost $133.7 million in 1986 Canadian dollars to seal three reference shafts, including $18 million for labour and equipment, $103.4 million for backfill and sealing materials, $9.5 million for project indirect costs, and $2.8 million project management. (author). 53 refs., 36 tabs., 43 figs.

Conceptual design of shaft seals for a nuclear waste disposal vault

International Nuclear Information System (INIS)

1993-04-01

The concept of a disposal vault in the Canadian Shield for the effective isolation of nuclear fuel wastes is being assessed as part of the Canadian Nuclear Fuel Waste Management Program. The vault would be accessed from the surface by a number of shafts, which would likely penetrate the vault environment and intersect significant rock fractures and thereby form preferential pathways for the migration of radionuclides from the disposal area to the biosphere. Golder Associates were retained to conduct a conceptual design study of sealing and backfilling the shafts. The first volume of this report reviews current shaft sinking and lining technologies, and recommends the preferred construction methods for the shafts. Factors that could affect the design of a shaft seal system are reviewed, and a conceptual shaft seal is proposed. The second volume addresses the performance assessment of a shaft seal system. While there are no specific performance criteria against which to compare the anticipated containment characteristics of the shaft seal system proposed, the methodology developed for the performance assessment of the reference design should enable the design to be modified to meet performance criteria as they are developed. The report estimates that it will cost $133.7 million in 1986 Canadian dollars to seal three reference shafts, including $18 million for labour and equipment, $103.4 million for backfill and sealing materials, $9.5 million for project indirect costs, and $2.8 million project management. (author). 53 refs., 36 tabs., 43 figs

Implementation of Statistical Process Control: Evaluating the Mechanical Performance of a Candidate Silicone Elastomer Docking Seal

Science.gov (United States)

Oravec, Heather Ann; Daniels, Christopher C.

2014-01-01

The National Aeronautics and Space Administration has been developing a novel docking system to meet the requirements of future exploration missions to low-Earth orbit and beyond. A dynamic gas pressure seal is located at the main interface between the active and passive mating components of the new docking system. This seal is designed to operate in the harsh space environment, but is also to perform within strict loading requirements while maintaining an acceptable level of leak rate. In this study, a candidate silicone elastomer seal was designed, and multiple subscale test articles were manufactured for evaluation purposes. The force required to fully compress each test article at room temperature was quantified and found to be below the maximum allowable load for the docking system. However, a significant amount of scatter was observed in the test results. Due to the stochastic nature of the mechanical performance of this candidate docking seal, a statistical process control technique was implemented to isolate unusual compression behavior from typical mechanical performance. The results of this statistical analysis indicated a lack of process control, suggesting a variation in the manufacturing phase of the process. Further investigation revealed that changes in the manufacturing molding process had occurred which may have influenced the mechanical performance of the seal. This knowledge improves the chance of this and future space seals to satisfy or exceed design specifications.

Demonstrating the sealing of a deep geologic repository: the RECAP project

International Nuclear Information System (INIS)

Kuzyk, G.W.; Dixon, D.A.; Martino, J.B.; Kozak, E.T.; Bilinsky, D.M.; Thompson, P.M.

2006-01-01

Atomic Energy of Canada Limited (AECL) has operated an Underground Research Laboratory (URL) for twenty-three years (1982-2005). The URL was designed and constructed to carry out in situ geotechnical R and D needed for the Canadian Nuclear Fuel Waste Management program. The facility is now being closed, the final of several phases that have included siting, site evaluation, construction and operation. The closure phase presents a unique opportunity to develop and demonstrate the methodologies needed for closure and site restoration of a deep geologic repository for used nuclear fuel. A wealth of technical background and characterization data, dating back to before the first excavation work was carried out, are available to support closure activities. A number of closure-related activities are being proposed as part of a REpository Closure And Post-closure (RECAP) project. The RECAP project is proposed to include demonstrations of shaft and borehole sealing and monitoring as well as fracture sealing (grouting), room closure and monitoring system decommissioning, all activities that would occur when closing an actual repository. In addition to the closure-related activities, the RECAP project could provide a unique opportunity to conduct intrusion-monitoring demonstrations as part of a repository safeguards demonstration. (author)

Status of harbour seals (Phoca vitulina in Atlantic Canada

Directory of Open Access Journals (Sweden)

Mike O Hammill

2010-09-01

Full Text Available Harbour seals are associated with small islets, reefs and rocks exposed at low tide and estuarine habitats throughout eastern Canada. Evidence of harvesting by indigenous people has been found in pre-European contact archaeological excavations. A bounty harvest as well as subsistence and commercial hunting probably lead to a decline in the population from 1949 to the early 1970s. The bounty was removed in 1976, and harbour seals, in the southern parts of their range have been protected since then. There is little information available on total abundance and current population trend. Mitochondrial and microsatellite DNA research has shown separation between Northeast and Northwest Atlantic harbour seals. Within Canada, the subspecies Phoca vitulina concolor shows some population sub-structure with three distinct units that could be separated into Hudson Bay, Gulf of St. Lawrence and Sable Island. Urban development resulting in habitat degradation is probably the most important factor affecting harbour seal populations in AtlanticCanada, although other factors such as incidental catches in commercial fisheries and competition with grey seals may also be important.

Developments in the Deployment of Ultrasonic Bolt Seals at the Storage Ponds of a Large Reprocessing Plant

International Nuclear Information System (INIS)

Lahogue, Y.; Synetos, S.; Lupo, J.; Piron, V.; ); Littmann, F.; Sironi, M.; )

2015-01-01

At the ponds of La Hague (F) different types of material are stored awaiting reprocessing: · Irradiated LEU fuel assemblies, · Fresh MOX scrap of different origins, · Irradiated MOX assemblies from research reactors, · Irradiated L/HEU assemblies from research reactors. According to the safeguard approach developed by Euratom, irradiated LEU fuel is verified by Cerenkov viewing devices. Other fuel types are verified with a dedicated under water neutron/gamma detector. The measurements are resource intensive for both inspector and operator. In addition one of the measurement points will be decommissioned by 2015. Thus ultrasonic bolt seals (USBS) were identified as a suitable means to keep continuity of knowledge and reduce inspection effort. The paper describes currently required measurements and related high effort and compares with the effort to place and read USBS. The discussion will focus on the activities required for un-irradiated MOX scrap, which are of particularly high safeguards interest, and will describe the measures implemented to minimize re-measurement needs. The significant savings will be demonstrated. Under the new approach USBS are placed on all newly arriving baskets, following verification by NDA. Baskets already in the pond will be sealed with USBS step by step. The current status will be discussed. In order to make this project possible, JRC Ispra supplied a new generation of USBS reading heads, electronics and software. The paper will describe the significant improvements of the technology versus earlier generations. (author)

Pool gateway seal

International Nuclear Information System (INIS)

Starr, J.A.; Steinert, L.A.

1983-01-01

A device for sealing a gateway between interconnectable pools in a nuclear facility comprising a frame supporting a liquid impermeable sheet positioned in a u-shaped gateway between the pools. An inflatable tube carried in a channel in the periphery of the frame and adjoining the gateway provides a seal therebetween when inflated. A restraining arrangement on the bottom edge of the frame is releasably engagable with an adjacent portion of the gateway to restrict the movement of the frame in the u-shaped gateway upon inflation of the tube, thereby enhancing the seal. The impermeable sheet is formed of an elastomer and thus is conformable to a liquid permeable supportive wall upon application of liquid pressure to the side of the sheet opposite the wall

Ultrasonicly identified seals for safeguards and physical protection purposes

International Nuclear Information System (INIS)

Crutzen, S.

The paper provides a general review of an ultrasonic technique available for sealing, marking or otherwise identifying material in such a way that its recognition and guarantee of integrity are inequivocally ensured. Development work on several types of seals and their ultrasonic identification has been performed at Ispra in collaboration with external companies for application to MTRs, HWRs and FBRs

Stress Mapping in Glass-to-Metal Seals using Indentation Crack Lengths.

Energy Technology Data Exchange (ETDEWEB)

Strong, Kevin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Buchheit, Thomas E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Diebold, Thomas Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Newton, Clay S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bencoe, Denise N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stavig, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jamison, Ryan Dale [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-08-01

Predicting the residual stress which develops during fabrication of a glass-to-metal compression seal requires material models that can accurately predict the effects of processing on the sealing glass. Validation of the predictions requires measurements on representative test geometries to accurately capture the interaction between the seal materials during a processing cycle required to form the seal, which consists of a temperature excursion through the glass transition temperature of the sealing glass. To this end, a concentric seal test geometry, referred to as a short cylinder seal, consisting of a stainless steel shell enveloping a commercial sealing glass disk has been designed, fabricated, and characterized as a model validation test geometry. To obtain data to test/validate finite element (FE) stress model predictions of this geometry, spatially-resolved residual stress was calculated from the measured lengths of the cracks emanating from radially positioned Vickers indents in the glass disk portion of the seal. The indentation crack length method is described, and the spatially-resolved residual stress determined experimentally are compared to FE stress predictions made using a nonlinear viscoelastic material model adapted to inorganic sealing glasses and an updated rate dependent material model for 304L stainless steel. The measurement method is a first to achieve a degree of success for measuring spatially resolved residual stress in a glass-bearing geometry and a favorable comparison between measurements and simulation was observed.

Stress Mapping in Glass-to-Metal Seals using Indentation Crack Lengths

Energy Technology Data Exchange (ETDEWEB)

Buchheit, Thomas E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Component & Systems Analysis; Strong, Kevin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Material Mechanics and Tribology; Newton, Clay S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Material Mechanics and Tribology; Diebold, Thomas Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Material Mechanics and Tribology; Bencoe, Denise N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Electronic, Optical and Nano; Stavig, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Organic Materials Science; Jamison, Ryan Dale [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Transportation System Analysis

2017-08-01

Predicting the residual stress which develops during fabrication of a glass-to-metal compression seal requires material models that can accurately predict the effects of processing on the sealing glass. Validation of the predictions requires measurements on representative test geometries to accurately capture the interaction between the seal materials during a processing cycle required to form the seal, which consists of a temperature excursion through the glass transition temperature of the sealing glass. To this end, a concentric seal test geometry, referred to as a short cylinder seal, consisting of a stainless steel shell enveloping a commercial sealing glass disk has been designed, fabricated, and characterized as a model validation test geometry. To obtain data to test/validate finite element (FE) stress model predictions of this geometry, spatially-resolved residual stress was calculated from the measured lengths of the cracks emanating from radially positioned Vickers indents in the glass disk portion of the seal. The indentation crack length method is described, and the spatially-resolved residual stress determined experimentally are compared to FE stress predictions made using a nonlinear viscoelastic material model adapted to inorganic sealing glasses and an updated rate dependent material model for 304L stainless steel. The measurement method is a first to achieve a degree of success for measuring spatially resolved residual stress in a glass-bearing geometry and a favorable comparison between measurements and simulation was observed.

CBM sealing system and its relationship with CBM enrichment

Directory of Open Access Journals (Sweden)

Yonglin Ouyang

2017-01-01

Full Text Available It is of great significance to study the controlling effect of sealing systems on CBM enrichment in coalbed methane (CBM exploration and development. In this paper, the relationships between CBM enrichment and geological elements were analyzed. The geological elements include sealing layers (e.g. regional cap rock, regional floor, and immediate roof and floor, later structural adjustment and strata production status. It is shown that CBM tends to enrich in the areas where regional mudstone cap rocks and floors are distributed stably, structures are uplifted and inversed slightly after the hydrocarbon accumulation period and the strata is gentle in a balanced state. Then, the concept of sealing system was put forward based on the worldwide CBM exploration and development practices over the years. A sealing system refers to a geological unit composed of a lateral stable zone and cap rock which prevents gas from migrating upward and downward. In a sealing system, CBM can get enriched and coal-measure gas can also be accumulated. Finally, three gas reservoir types (i.e., sandwich-type CBM reservoir, associated CBM-sandstone gas reservoir and coal-derived sandstone gas reservoir were identified based on the configuration relationships between elements of the CBM (or coal-measure gas sealing system. It is recommended to change the exploration ideas from simple CBM exploration to 3D CBM and coal-measure gas exploration. In addition, an evaluation index system of CBM (or coal-measure gas geological selection was established. It is pointed out that good application effects may be realized if the stereoscopic CBM and coal-measure gas exploration is applied in the Junggar Basin and the eastern margin of the Ordos Basin.

Fabrication of sealed radiation sources

International Nuclear Information System (INIS)

Mars, Jean.

1977-01-01

The description is given for fabricating a sealed radiation source, consisting in depositing on a metal substrate a thin active coat of a radioelement, termed first coat, submitting this coated substrate to an oxidation treatment in order to obtain on the first coat an inactive coat of an oxide of the metal, termed second coat, and depositing a coat of varnish on this second inactive coat [fr

A new concept in rotary shaft seal lubrication : viscoelastohydrodynamic (VEHD) lubrication

NARCIS (Netherlands)

Leeuwen, van H.J.; Stakenborg, M.J.L.; Dowson, D.; Taylor, C.M.; Godet, M.

1991-01-01

In practice rotary shaft seals will experience a small-amplitude dynamic excitation. It is shown that under periodic excitation circumferentially nonuniform clearances develop due to viscous seal material behaviour. The nearby fluid will fill these gaps, so entrainment and squeeze effects can

Fracture Sealing in Shales: Geological and Geochemical Factors

International Nuclear Information System (INIS)

Cathelineau, Michel

2001-01-01

The so-called self-sealing processes can be re-examined at the light of geological and geochemical consideration about the past history of the rocks. The concept of 'self sealing' needs to consider the formation and the sealing of fractures, especially three main stages: (i) the initiation of the fracture (development of micro-cracks initiated from previous heterogeneities up to fracturing), ii) the fracturing processes which occur generally at depth in presence of a fluid phase, iii) the healing or sealing of the fractures which corresponds basically to two main processes: a restoration of the initial permeability of the rock block by reducing the transmissivity of the discontinuity down to values equivalent to that of the homogeneous medium before fracturing, or the sealing of the open discontinuity by precipitation of newly formed minerals. In the latter case, the evolution of the open fracture is driven by re-arrangement of particles or precipitation of newly formed material, either by dissolution/crystallisation processes or by crystallisation from the percolating fluids (advective processes). Such processes are governed by chemical processes, especially the rate of precipitation of minerals which depends of the degree of saturation with respect to the mineral, and the kinetics of precipitation. (author)

SEAL FOR HIGH SPEED CENTRIFUGE

Science.gov (United States)

Skarstrom, C.W.

1957-12-17

A seal is described for a high speed centrifuge wherein the centrifugal force of rotation acts on the gasket to form a tight seal. The cylindrical rotating bowl of the centrifuge contains a closure member resting on a shoulder in the bowl wall having a lower surface containing bands of gasket material, parallel and adjacent to the cylinder wall. As the centrifuge speed increases, centrifugal force acts on the bands of gasket material forcing them in to a sealing contact against the cylinder wall. This arrangememt forms a simple and effective seal for high speed centrifuges, replacing more costly methods such as welding a closure in place.

A 3D-CFD code for accurate prediction of fluid flows and fluid forces in seals

Science.gov (United States)

Athavale, M. M.; Przekwas, A. J.; Hendricks, R. C.

1994-01-01

Current and future turbomachinery requires advanced seal configurations to control leakage, inhibit mixing of incompatible fluids and to control the rotodynamic response. In recognition of a deficiency in the existing predictive methodology for seals, a seven year effort was established in 1990 by NASA's Office of Aeronautics Exploration and Technology, under the Earth-to-Orbit Propulsion program, to develop validated Computational Fluid Dynamics (CFD) concepts, codes and analyses for seals. The effort will provide NASA and the U.S. Aerospace Industry with advanced CFD scientific codes and industrial codes for analyzing and designing turbomachinery seals. An advanced 3D CFD cylindrical seal code has been developed, incorporating state-of-the-art computational methodology for flow analysis in straight, tapered and stepped seals. Relevant computational features of the code include: stationary/rotating coordinates, cylindrical and general Body Fitted Coordinates (BFC) systems, high order differencing schemes, colocated variable arrangement, advanced turbulence models, incompressible/compressible flows, and moving grids. This paper presents the current status of code development, code demonstration for predicting rotordynamic coefficients, numerical parametric study of entrance loss coefficients for generic annular seals, and plans for code extensions to labyrinth, damping, and other seal configurations.

Dynamics of vacuum-sealed, double-leaf partitions

Science.gov (United States)

Kavanaugh, Joshua Stephen

The goal of this research is to investigate the feasibility and potential effectiveness of using vacuum-sealed, double-leaf partitions for applications in noise control. Substantial work has been done previously on double-leaf partitions where the acoustics of the inner chamber and mechanical vibrations of structural supports are passively and actively controlled. The work presented here is unique in that the proposed system aims to eliminate the need for active acoustic control of transmitted acoustic energy by removing all the air between the two panels of the double partition. Therefore, the only remaining energy paths would be along the boundary and at the points where there are intermediate structural supports connecting the two panels. The eventual goal of the research is to develop a high-loss double-leaf partition that simplifies active control by removing the need for control of the air cavity and channeling all the energy into discrete structural paths. The work presented here is a first step towards the goal of designing a high-loss, actively-controlled double-leaf partition with an air-evacuated inner chamber. One experiment is conducted to investigate the effects of various levels of vacuum on the response of a double-leaf partition whose panels are mechanically coupled only at the boundary. Another experiment is conducted which investigates the effect of changing the stiffness of an intermediate support coupling the two panels of a double-leaf partition in which a vacuum has been applied to the inner cavity. The available equipment was able to maintain a 99% vacuum between the panels. Both experiments are accompanied by analytical models used to investigate the importance of various dynamic parameters. Results show that the vacuum-sealed system shows some potential for increased transmission loss, primarily by the changing the natural frequencies of the double-leaf partition.

Modeling the effect of seal leakage on spontaneous heating in a longwall gob area

Energy Technology Data Exchange (ETDEWEB)

Smith, A.C.; Yuan, L. [National Inst. for Occupational Safety and Health, Pittsburgh, PA (United States). Office of Mine Safety and Health Research

2010-07-01

Three coal mines in the United States with a history of spontaneous combustion use a bleederless ventilation system as a control measure. In a bleederless system, one of the headgate entries is used as the tailgate entry of the succeeding panel and is isolated from the gob of the active panel by gob seals that are installed in the headgate entry as the face advances. An active longwall panel using a Y-type bleederless ventilation system was simulated in this study. As longwall mining progresses, some seals are known to leak. Computational fluid dynamics (CFD) simulations were performed to study the effect of seal leakage on spontaneous heating of coal in the longwall gob area. The simulation results showed that under typical bleederless ventilation conditions, the maximum temperature in the gob increased with an increase in leakage rate. The maximum temperature occurred at the headgate side corner at the back end of the panel. When only 1 or 2 seals were leaking, the maximum temperature occurred around the seal. The results demonstrate that complex interactions between pressure differential and gob permeability at different locations in the gob cause ventilation pathways. The interactions depend greatly on gob permeability and seal leakage rates. 8 refs., 1 tab., 14 figs.

Seal Apparatus and Methods to Manufacture Thereof

Science.gov (United States)

Richard, James A. (Inventor)

2013-01-01

In some implementations, apparatus and methods are provided through which a dynamic cryogenic seal is manufactured. In some implementations, the seal includes a retainer and a spring-seal assembly, the assembly being comprised of a main spring housing and fluorine-containing polymer seals. In some implementations, either a radial seal, or an axial (or "piston seal") is provided. In some implementations, methods of manufacturing the dynamic cryogenic seal are also provided. In some implementations, the methods include assembling the components while either heated or cooled, taking advantage of thermal expansion and contraction, such that there is a strong interference fit between the components at room temperature. In some implementations, this process ensures that the weaker fluorine-containing polymer seal is forced to expand and contract with the stronger retainer and spring and is under constant preload. In some implementations, the fluorine-containing polymer is therefore fluidized and retained, and can not lift off.

Design and production of activimeters verification sealed radioactive sources

International Nuclear Information System (INIS)

Serra, R.; Hernandez Rivero, A. T.; Oropesa, P.; Rapado, M.; Falcon, L.

2006-01-01

Measurement in a radionuclide calibrator (activimeter) of the doses to be administered to a patient for diagnosis or radiotherapeutic treatment is an essential element in Nuclear Medicine practice. To assure that patient will receive the optimal doses that guarantee the necessary quality of the image to be studied or optimum radiotherapeutic effect, the activity determination should fulfil established accuracy requirements. To this aim, the overall uncertainty in activity determination must not surpass a preestablished limit of about 10 % for the expanded uncertainty of the activity value (with a coverage factor k = 3). To have suitable equipment, periodically calibrated for specialized and authorized specialists and frequently verified in inter calibration periods to guarantee detection of any malfunctioning, are essential requirements to assure the compliance with the prescribed regulations and limiting values. This paper describes the design and production of two models of 137 Cs activimeters verification sealed radioactive sources elaborated with this aim at the Radionuclide Metrology Department of the Isotope Centre of Cuba. Taking into account the international experience in this field was defined 3 -10 MBq as convenient activity range, the 137 Cs as a suitable radionuclide, and a classification ISO/99/C22212 (ISO 2919:1999) for the sealed sources to be obtained. In designed and produced models the activity is bonded in a hydrogel copolymer obtained by gamma irradiation, in a 60 Co irradiator, of a mixture of a 137 Cs aqueous solution with an approximate activity of 5 MBq with two proper monomers (acrylamide and methacrylic acid). The density of obtained copolymer is similar to that of the radioactive solutions employed in nuclear medicine departments for diagnosis and therapy. The obtained sources have appropriate physical stability for a temperature range between 40 o C below zero and 80 o C, as well as for defined activity range. The stability of the

Evaluation of the leakage behavior of inflatable seals subject to severe accident conditions

International Nuclear Information System (INIS)

Parks, M.B.

1989-11-01

Sandia National Laboratories, under the sponsorship of the United States Nuclear Regulatory Commission, is currently developing test validated methods to predict the pressure capacity of light water reactor containment buildings when subjected to postulated severe accident conditions. These conditions are well beyond the design basis. Scale model tests of steel and reinforced concrete containments have been conducted as well as tests of typical containment penetrations. As a part of this effort, a series of tests was recently conducted to determine the leakage behavior of inflatable seals. These seals are used to prevent leakage around personnel and escape lock doors of some containments. The results of the inflatable seals tests are the subject of this report. Inflatable seals were tested at both room temperature and at elevated temperatures representative of postulated severe accident conditions. Both aged (radiation and thermal) and unaged seals were included in the test program. The internal seal pressure at the beginning of each test was varied to cover the range of seal pressures actually used in containments. For each seal pressure level, the external (containment) pressure was increased until significant leakage past the seals was observed. Parameters that were monitored and recorded during the tests were the internal seal pressure, chamber pressure, leakage past the seals, and temperature of the test chamber and fixture to which the seals were attached. 8 refs., 34 figs., 7 tabs

A dynamic analysis of rotary combustion engine seals

Science.gov (United States)

Knoll, J.; Vilmann, C. R.; Schock, H. J.; Stumpf, R. P.

1984-01-01

Real time work cell pressures are incorporated into a dynamic analysis of the gas sealing grid in Rotary Combustion Engines. The analysis which utilizes only first principal concepts accounts for apex seal separation from the crochoidal bore, apex seal shifting between the sides of its restraining channel, and apex seal rotation within the restraining channel. The results predict that apex seals do separate from the trochoidal bore and shift between the sides of their channels. The results also show that these two motions are regularly initiated by a seal rotation. The predicted motion of the apex seals compares favorably with experimental results. Frictional losses associated with the sealing grid are also calculated and compare well with measurements obtained in a similar engine. A comparison of frictional losses when using steel and carbon apex seals has also been made as well as friction losses for single and dual side sealing.

Mechanical seal having a double-tier mating ring