Modeling valve leakage

International Nuclear Information System (INIS)

Bell, S.R.; Rohrscheib, R.

1994-01-01

The American Society of Mechanical Engineers (ASME) Code requires individual valve leakage testing for Category A valves. Although the U.S. Nuclear Regulatory Commission (USNRC) has recognized that it is more appropriate to test containment isolation valves in groups, as allowed by 10 CFR 50, Appendix J, a utility seeking relief from these Code requirements must provide technical justification for the relief and establish a conservative alternate acceptance criteria. In order to provide technical justification for group testing of containment isolation valves, Illinois Power developed a calculation (model) for determining the size of a leakage pathway in a valve disc or seat for a given leakage rate. The model was verified experimentally by machining leakage pathways of known size and then measuring the leakage and comparing this value to the calculated value. For the range of values typical of leakage rate testing, the correlation between the experimental values and calculated values was quote good. Based upon these results, Illinois Power established a conservative acceptance criteria for all valves in the inservice testing (IST) program and was granted relief by the USNRC from the individual leakage testing requirements of the ASME Code. This paper presents the results of Illinois Power's work in the area of valve leakage rate testing

Effects of secondary containment air cleanup system leakage on the accident offsite dose as determined during preop tests of the Sequoyah Nuclear Plant

International Nuclear Information System (INIS)

Klaes, L.J.; Nass, S.A.; Proctor, L.D.

1981-01-01

The Sequoyah Nuclear Plant has two secondary containments. One is the annular region between the primary containment and the shield building surrounding the primary containment. The second is the auxiliary building secondary containment enclosure which is potentially subject to direct airborne radioactivity. Two air cleanup systems are provided to serve these areas. The emergency gas treatment system (EGTS) serves the annulus between the primary containment and the shield building, and the auxiliary building gas treatment system (ABGTS) serves the area inside of the auxiliary building secondary containment enclosure. The major function served by these air cleanup systems is that of controlling and processing airborne contamination released in these areas during any accident up to a design basis accident. This is accomplished by (1) creating a negative pressure in the areas served to ensure that no unprocessed air is released to the atmosphere, (2) providing filtration units to process all air exhausted from the secondary containment spaces, and (3) providing a low-leakage enclosure to limit exhaust flows. Offsite dose effects due to secondary containment release rates, bypass leakage, and duct and damper leakages are presented and parameter variations are considered. For the EGTS, a recirculation system, the most important parameter is the total inleakage of the system which causes an increase in both whole body (gamma) and thyroid (iodine) doses. For the ABGTS, a once-through system, the most important paramter is the inleakage which bypasses the filters resulting in an increase in the thyroid dose only. Actual preoperational test data are utilized. Problems encountered during the preop test are summarized. Solutions incorporated to bring the EGTS and ABGTS air cleanup systems within the test acceptance criteria required to meet offsite dose limitations are discussed and the resultant calculated offsite dose is presented

Testing to determine the leakage behavior of inflatable seals subject to severe accident loadings

International Nuclear Information System (INIS)

Parks, M.B.

1988-01-01

Under the sponsorship of the United States Nuclear Regulatory Commission, Sandia National Laboratories is currently developing test validated methods to predict the pressure capacity, at elevated temperatures, of light water reactor (LWR) nuclear containment vessels subject to loads well beyond their design basis - the so-called severe accident. Scale model tests of containments with the major penetrations represented have been carried to functional failure by internal pressurization. Also, combined pressure and elevated temperature tests of typical compression seals and gaskets, a full size personnel airlock, and of typical electrical penetration assemblies (EPAs), have been conducted in order to better understand the leakage behavior of containment penetrations. Because inflatable seals are also a part of the pressure boundary of some containments, it is important to understand their leakage behavior as well. This paper discusses the results of tests that were performed to better define the leakage behavior of inflatable seals when subjected to loads well beyond their design basis

Examination of leakage aspects through concrete - steel interfaces at and around containment penetration assemblies

International Nuclear Information System (INIS)

Chakrabarti, S.K.; Sai, A.S.R.; Basu, P.C.

1994-01-01

Penetration assemblies are parts required to be provided in the containment wall/dome to permit piping, mechanical devices, equipments, electrical cables, personnel movements etc. Integrity of arrangements with respect to leak tightness at or around these penetration assemblies, is of utmost importance for achieving safe functioning of containment. Considering the feasibilities in controlling leakages along different possible paths, it has been found necessary to examine in detail the leakage possibilities at concrete - steel interfaces at and around penetration assemblies. The present paper addresses this issue with respect to the important related aspects like constructional details, testing conditions, normal operating conditions, and the accidental situation associated with containment structures. (author)

A performance-oriented and risk-based regulation for containment testing

International Nuclear Information System (INIS)

Dey, M.

1994-01-01

In August 1992, the NRC initiated a major initiative to develop requirements for containment testing that are less prescriptive, and more performance-oriented and risk-based. This action was a result of public comments and several studies that concluded that the economic burden of certain, present containment testing requirements are not commensurate with their safety benefits. The rulemaking will include consideration of relaxing the allowable containment leakage rate, increasing the interval for the integrated containment test, and establishing intervals for the local containment leak rate tests based on their performance. A study has been conducted to provide technical information for establishing the performance criteria for containment tests, the allowable leakage rate, commensurate with its significance to total public risk. The study used results of a recent comprehensive study conducted by the NRC, NUREG-1150, 'Severe Accident Risks: An Assessment for Five U.S. Nuclear Power Plants,' to examine the sensitivity of containment leakage to public risk. Risk was found to be insensitive to containment leakage rate up to levels of about 100 percent-volume per day for certain types of containments. PRA methods have also been developed to establish risk-based intervals for containment tests based on their past experience. Preliminary evaluations show that increasing the interval for the integrated containment leakage test from three times to once every ten years would have an insignificant impact on public risk. Preliminary analyses of operational experience data for local leak rate tests show that performance-based testing, valves and penetrations that perform well are tested less frequently, is feasible with marginal impact on safety. The above technical studies are being used to develop efficient (cost-effective) requirements for containment tests. (author). 4 refs., 2 figs

Automation of unit for leakage test

OpenAIRE

LYCHKOVSKAYA V.S.; TSYGANKOV A.S.; GRINBERG G.M.; STANOVOVA O.A.

2015-01-01

Federal state educational standard requirements for training of university students have been considered. Leakage test procedures for components of aerospace vehicles have been described. Automation procedures of existing laboratory leakage test units have been outlined.

Method of detecting leakage in nuclear reactor containment vessel

International Nuclear Information System (INIS)

Koba, Akitoshi; Goto, Seiichiro.

1974-01-01

Object: To permit accurate and prompt detection of leakage of a radioactive substance. Structure: The rate of change of such factors as radiation dose, temperature and pressure in the containment vessel, and each detected rate of change is compared with a reference value. The running cycle of the condensed drain exhausting pump in a drain collecting tank within a predetermined period is detected, and it is also compared with a reference value. These comparisons determine the absence or presence of leakage. (Kamimura, M.)

In-depth analysis of eight criteria for integrated leakage rate tests for nuclear power plant containment buildings

International Nuclear Information System (INIS)

Wagner, W.T.; Langan, J.P.; Norris, W.F.; Lurie, D.

1989-01-01

A U.S. Nuclear Regulatory Commission (NRC) Small Business Innovation research (SBIR) Contract investigated ten integrated leakage rate test (ILRT) analysis models which have been proposed for evaluation of ILRT data. This contract involved in-depth analysis of two ILRTs with data collected at accelerated rates and 80 conventional ILRTs with data collected at a frequency between 10-15 minutes. All ten methods were applied to all data. The study considered the appropriateness of each method to analyze containment data (air mass versus time), the influence of data collection frequency on ILRT duration, and the influence of collection frequency on each method. The study is described in the paper. Results are presented

Leakage detection system in nuclear reactor container

International Nuclear Information System (INIS)

Kurosawa, Masahiko.

1993-01-01

The present invention comprises an injection means for adding radioactive materials to coolants in a container cooler, a gamma ray amplitude analyzer connected to coolant pipelines and a means for recording/transferring the data of the result of the measurement, a gamma ray amplitude analyzer connected to a drain water sump and a means for recording/transferring the data of the result of the measurement, a gamma ray amplitude analyzer connected to various kinds of pipelines and a means for recording/transferring the data of the result of the measurement, and a data processing means for comparing and analyzing the measured data of each of the gamma ray amplitude analyzers inputted from each of date recording/transferring means. The gamma ray amplitude analysis for each of the pipelines and drain water sump are conducted at an appropriate frequency, and the measured data are compared and analyzed, to improve the detection accuracy for a trace amount of leakage from each of the pressure pipelines and the container cooler coolant pipelines, thereby enabling to specify the pipeline having leakage. Maintenance efficiency is improved, and severe rupture accident in each of pressure pipelines is prevented previously. (N.H.)

Elements for computing and forecasting the leakage rate of the inner containment of nuclear reactor buildings

International Nuclear Information System (INIS)

Asali, M.; Capra, B.; Mazars, J.; Colliat, J.B.

2015-01-01

This study aims at introducing a methodology based on a macro-element discretization to compute and forecast the air leak rate of double-wall reactor buildings during air pressure tests. Assumptions at the basis of a weakly coupled strategy are checked in the case of a typical porous concrete section of an inner containment modeled during a 33 year period including four decennial regulatory pressure tests. However, air leakage due to porosity is only part of in situ measurements. Leakage due to cracking is another part and should be taken into account. A first macro-element is then presented, that superimposes Darcy flow within a porous matrix together with Poiseuille flow within a crack. Those elements are then used in a 3D hydraulic model to compute more accurately the total air leakage rate of considered structures. (authors)

Leakage of pressurized gases through unlined concrete containment structures

International Nuclear Information System (INIS)

Rizkalla, S.H.; Simmonds, S.H.

1983-01-01

Eight reinforced concrete specimens were fabricated and subjected to tensile membrane forces and air pressure to study the air leakage characteristics in cracked reinforced concrete members. A mathematical expression for the rate of pressurized air flowing through an idealized crack is presented. The mathematical expression is refined by using the experimental data to describe the air flow rate through any given crack pattern. Graphical charts are also presented for the calculation of the air leakage rate through concrete cracks. The concept of equivalent crack width for a given crack pattern is introduced. The mathematical expression and graphical charts are modified to include this equivalent crack width concept. The proposed technique is applicable for the prediction of the leakage from concrete containment structures or any similar structures due to high internal pressure sufficient to initiate cracking. (orig.)

Leakage evaluation in the PCV (Primary Containment Vessel) using chemical and radiochemical data

International Nuclear Information System (INIS)

Maeda, Katsuji; Nagasawa, Katsumi

1998-01-01

Keeping the reliability of nuclear power plant operation, the primary coolant leakage in the PCV is strictly restricted by the Technical Specifications. It is very important to detect an indication of leakage and estimate the source of leakage to provide countermeasures. Usually the indication of leakage will be detected by increase of drain flow in the PCV sump. There are some possibilities of leakage sources in the PCV, such as reactor water, main steam, condensate, feedwater and closed cooling water. The leakage source contain different chemical and radiochemical species. This means that the leakage source can be presumed and detected by using chemical information from the PCV atmosphere and sump water. To detect the leakage indication and the source quickly and exactly, the PCV Leakage Detection Expert System has been developed. This paper describes how to evaluate the leakage indication and source in the PCV by using chemical and radiochemical data. (author)

Leakage detecting method and device for water tight vessel of wet-type container apparatus

International Nuclear Information System (INIS)

Tanaka, Yoshimi.

1995-01-01

The present invention provides a method of and a device for detecting leakage of a water tight vessel of a wet-type container apparatus for containing a reactor pressure vessel while immersing it water in a reactor container. Namely, in the wet-type container apparatus, the periphery of the pressure vessel is coated with a heat insulation material and the periphery of the heat insulation material is coated with a water tight vessel. The water tight vessel is immersed under water in the reactor container. As a method of detecting leakage of the wet-type container apparatus, gases mixed with helium are supplied into the water tight vessel at a pressure higher than the inner pressure of the reactor container at a lowest position of the reactor pressure vessel. A water level in the reactor container is determined so as to form a space at the top portion of the inside of the reactor container. The helium at the top portion is detected to monitor the leakage of the water tight vessel. With such procedures, even if the water tight vessel is ruptured at any position, helium mixed to the gases is released to water in the reactor container and rise up to the top space and detected by a helium leakage detection device. (I.S.)

Analytical methods of leakage rate estimation from a containment under a LOCA

International Nuclear Information System (INIS)

Chun, M.H.

1981-01-01

Three most outstanding maximum flow rate formulas are identified from many existing models. Outlines of the three limiting mass flow rate models are given along with computational procedures to estimate approximate amount of fission products released from a containment to environment for a given characteristic hole size for containment-isolation failure and containment pressure and temperature under a loss of coolant accident. Sample calculations are performed using the critical ideal gas flow rate model and the Moody's graphs for the maximum two-phase flow rates, and the results are compared with the values obtained from then mass leakage rate formula of CONTEMPT-LT code for converging nozzle and sonic flow. It is shown that the critical ideal gas flow rate formula gives almost comparable results as one can obtain from the Moody's model. It is also found that a more conservative approach to estimate leakage rate from a containment under a LOCA is to use the maximum ideal gas flow rate equation rather than the mass leakage rate formula of CONTEMPT-LT. (author)

The PACE-1450 experiment - Crack and leakage behavior of a pre-stressed concrete containment wall considering ageing

International Nuclear Information System (INIS)

Hermann, N.; Mueller, H.S.; Niklasch, C.; Michel-Ponnelle, S.; Bento, C.; Masson, B.

2015-01-01

As an intermediate sized experiment the PACE-1450 experiment aims to investigate the behavior of a curved specimen (length: 3.5 m, width: 1.8 m, height: 1.2 m) which is representative for a 1450 MWe nuclear power plant containment under accidental loading conditions. One focus of this experimental test campaign is the consideration of the ageing of the structure which among other effects leads to a pre-stressing loss. The crack behavior of the realistically reinforced specimen is of as much interest as it is the leakage behavior when an inner pressure occurs within the containment. The reinforcement layout of the specimen is very similar to the original geometry and consists mainly of reinforcement meshes of bars near the inner and outer surface and four pre-stressing cables in the circumferential direction. During the tests the specimen is loaded by pressure which simulates the internal accidental containment pressure of up to 6 bars (absolute pressure). The resulting ring tensile stress in the cylindrical part of the containment is externally applied by hydraulic jacks. An initial pre-stressing of the specimen of 12 MPa is realized in such a way that decreasing the pre-stressing force for the purpose of simulating the ageing of the structure is possible. The facility allows for the cracking of the pre-stressed specimen and for leakage measurements at different controlled crack widths. The specimen is equipped with embedded optical fiber strain and temperature sensors and a sound detection system to record the initiation of cracks. The paper explains the test set-up and presents results of the ongoing test series regarding the cracking and leakage behavior of the specimen

Uncertainty Analysis of In leakage Test for Pressurized Control Room Envelop

Energy Technology Data Exchange (ETDEWEB)

Lee, J. B. [KHNP Central Research Institute, Daejeon (Korea, Republic of)

2013-10-15

In leakage tests for control room envelops(CRE) of newly constructed nuclear power plants are required to prove the control room habitability. Results of the in leakage tests should be analyzed using an uncertainty analysis. Test uncertainty can be an issue if the test results for pressurized CREs show low in leakage. To have a better knowledge of the test uncertainty, a statistical model for the uncertainty analysis is described here and a representative uncertainty analysis of a sample in leakage test is presented. A statistical method for analyzing the uncertainty of the in leakage test is presented here and a representative uncertainty analysis of a sample in leakage test was performed. By using the statistical method we can evaluate the test result with certain level of significance. This method can be more helpful when the difference of the two mean values of the test result is small.

Uncertainty Analysis of In leakage Test for Pressurized Control Room Envelop

International Nuclear Information System (INIS)

Lee, J. B.

2013-01-01

In leakage tests for control room envelops(CRE) of newly constructed nuclear power plants are required to prove the control room habitability. Results of the in leakage tests should be analyzed using an uncertainty analysis. Test uncertainty can be an issue if the test results for pressurized CREs show low in leakage. To have a better knowledge of the test uncertainty, a statistical model for the uncertainty analysis is described here and a representative uncertainty analysis of a sample in leakage test is presented. A statistical method for analyzing the uncertainty of the in leakage test is presented here and a representative uncertainty analysis of a sample in leakage test was performed. By using the statistical method we can evaluate the test result with certain level of significance. This method can be more helpful when the difference of the two mean values of the test result is small

Nuclear Power Plant Prestressed Concrete Containment Vessel Structure Monitoring during Integrated Leakage Rate Testing Using Fiber Bragg Grating Sensors

Directory of Open Access Journals (Sweden)

Jinke Li

2017-04-01

Full Text Available As the last barrier of nuclear reactor, prestressed concrete containment vessels (PCCVs play an important role in nuclear power plants (NPPs. To test the mechanical property of PCCV during the integrated leakage rate testing (ILRT, a fiber Bragg grating (FBG sensor was used to monitor concrete strain. In addition, a finite element method (FEM model was built to simulate the progress of the ILRT. The results showed that the strain monitored by FBG had the same trend compared to the inner pressure variation. The calculation results showed a similar trend compared with the monitoring results and provided much information about the locations in which the strain sensors should be installed. Therefore, it is confirmed that FBG sensors and FEM simulation are very useful in PCCV structure monitoring.

Evaluation of the white test for the intraoperative detection of bile leakage.

Science.gov (United States)

Leelawat, Kawin; Chaiyabutr, Kittipong; Subwongcharoen, Somboon; Treepongkaruna, Sa-Ad

2012-01-01

We assess whether the White test is better than the conventional bile leakage test for the intraoperative detection of bile leakage in hepatectomized patients. This study included 30 patients who received elective liver resection. Both the conventional bile leakage test (injecting an isotonic sodium chloride solution through the cystic duct) and the White test (injecting a fat emulsion solution through the cystic duct) were carried out in the same patients. The detection of bile leakage was compared between the conventional method and the White test. A bile leak was demonstrated in 8 patients (26.7%) by the conventional method and in 19 patients (63.3%) by the White test. In addition, the White test detected a significantly higher number of bile leakage sites compared with the conventional method (Wilcoxon signed-rank test; P detection of bile leakage. Based on our study, we recommend that surgeons investigating bile leakage sites during liver resections should use the White test instead of the conventional bile leakage test.

Failure/leakage predictions of concrete structures containing cracks

International Nuclear Information System (INIS)

Pan, Y.C.; Marchertas, A.H.; Kennedy, J.M.

1984-06-01

An approach is presented for studying the cracking and radioactive release of a reactor containment during severe accidents and extreme environments. The cracking of concrete is modeled as the blunt crack. The initiation and propagation of a crack are determined by using the maximum strength and the J-integral criteria. Furthermore, the extent of cracking is related to the leakage calculation by using a model developed by Rizkalla, Lau and Simmonds. Numerical examples are given for a three-point bending problem and a hypothetical case of a concrete containment structure subjected to high internal pressure during an accident

Methods, means and results from containment leakage decrease in unit 2 at Kozloduy NPP with international participation

Energy Technology Data Exchange (ETDEWEB)

Demireva, E; Grigorov, D; Balabanov, E [Energoproekt, Sofia (Bulgaria)

1996-12-31

A study of the Kozloduy NPP Unit 2 containment improvement has been carried out. The following objectives are identified: to assess confinement tightness (local tests); to improve tightness; to perform the most urgent repair works; to develop global test procedures including leak tightness at nominal and reduced pressure, structural integrity test and venting flaps reliability test. Nine groups of potential leakage paths have been determined. The ventilation system has been found as the major source of expected leakage having 60 penetrations with size above 250 mm. Proposed modifications of the ventilation system include reduction of the number of inflow and suction valves, replacement of some valves with a better quality ones and installation of isolating valves. It is planned to transfer the experience and results of this study to the other WWER-440 units. 1 ref.

Methods, means and results from containment leakage decrease in unit 2 at Kozloduy NPP with international participation

International Nuclear Information System (INIS)

Demireva, E.; Grigorov, D.; Balabanov, E.

1995-01-01

A study of the Kozloduy NPP Unit 2 containment improvement has been carried out. The following objectives are identified: to assess confinement tightness (local tests); to improve tightness; to perform the most urgent repair works; to develop global test procedures including leak tightness at nominal and reduced pressure, structural integrity test and venting flaps reliability test. Nine groups of potential leakage paths have been determined. The ventilation system has been found as the major source of expected leakage having 60 penetrations with size above 250 mm. Proposed modifications of the ventilation system include reduction of the number of inflow and suction valves, replacement of some valves with a better quality ones and installation of isolating valves. It is planned to transfer the experience and results of this study to the other WWER-440 units. 1 ref

Evaluation of the White Test for the Intraoperative Detection of Bile Leakage

OpenAIRE

Leelawat, Kawin; Chaiyabutr, Kittipong; Subwongcharoen, Somboon; Treepongkaruna, Sa-ad

2012-01-01

We assess whether the White test is better than the conventional bile leakage test for the intraoperative detection of bile leakage in hepatectomized patients. This study included 30 patients who received elective liver resection. Both the conventional bile leakage test (injecting an isotonic sodium chloride solution through the cystic duct) and the White test (injecting a fat emulsion solution through the cystic duct) were carried out in the same patients. The detection of bile leakage was c...

Artificial-Crack-Behavior Test Evaluation of the Water-Leakage Repair Materials Used for the Repair of Water-Leakage Cracks in Concrete Structures

Directory of Open Access Journals (Sweden)

Soo-Yeon Kim

2016-09-01

Full Text Available There are no existing standard test methods at home and abroad that can verify the performance of water leakage repair materials, and it is thus very difficult to perform quality control checks in the field of water leakage repair. This study determined that the key factors that have the greatest impact on the water leakage repair materials are the micro-behaviors of cracks, and proposed an artificial-crack-behavior test method for the performance verification of the repair materials. The performance of the 15 kinds of repair materials that are currently being used in the field of water leakage repair was evaluated by applying the proposed test method. The main aim of such a test method is to determine if there is water leakage by injecting water leakage repair materials into a crack behavior test specimen with an artificial 5-mm crack width, applying a 2.5 mm vertical behavior load at 100 cycles, and applying 0.3 N/mm2 constant water pressure. The test results showed that of the 15 kinds of repair materials, only two effectively sealed the crack and thus stopped the water leakage. The findings of this study confirmed the effectiveness of the proposed artificial-crack-behavior test method and suggest that it can be used as a performance verification method for checking the responsiveness of the repair materials being used in the field of water leakage repair to the repetitive water leakage behaviors that occur in concrete structures. The study findings further suggest that the use of the proposed test method makes it possible to quantify the water leakage repair quality control in the field.

The White test: a new dye test for intraoperative detection of bile leakage during major liver resection.

Science.gov (United States)

Nadalin, Silvio; Li, Jun; Lang, Hauke; Sotiropoulos, Georgios C; Schaffer, Randolph; Radtke, Arnold; Saner, Fuat; Broelsch, Christoph E; Malagó, Massimo

2008-04-01

To describe a new intraoperative bile leakage test in patients undergoing a major liver resection aimed to combine the advantages of each of the other standard bile leakage tests (accurate visualization of leaks, reproducibility, and ease of use) without their disadvantages. At the end of the major hepatic resection, 10 to 30 mL of sterile fat emulsion, 5%, is injected via an olive-tip cannula through the cystic duct while manually occluding the distal common bile duct. As the biliary tree fills with fat emulsion solution, leakage of the white fluid is visualized on the raw surface of the liver resection margin. The detected leakages are closed by means of single stitches. Afterwards, the residual fat emulsion on the resection surface is washed off with saline and the White test is repeated to detect and/or exclude additional bile leakages. At the end, residual fat emulsion is washed out from the biliary tract by a low-pressure infusion of saline solution. Intraoperatively, additional potential bile leakages (not seen using a conventional saline bile leakage test) were identified in 74% of our patients. Postoperative bile leakages (within 30 days) occurred in only 5.1% of patients when the White test was used. No adverse effects related to this technique were observed. The White test has clear advantages in comparison with other bile leakage tests: it precisely detects bile leakages, regardless of size; it does not stain the resection surface, allowing it to be washed off and repeated ad infinitum; and it is safe, quick, and inexpensive.

Experimental study of the leakage rate through cracked reinforced concrete wall elements for defining the functional failure criteria of containment buildings

International Nuclear Information System (INIS)

Choun, Young Sun; Cho, Nam So

2004-01-01

Containment buildings in nuclear power plants should maintain their structural safety as well as their functional integrity during an operation period. To maintain the functional integrity, the wall and dome of the containment buildings have to maintain their air tightness under extreme loading conditions such as earthquakes, missile impact, and severe accidents. For evaluating the functional failure of containments, it is important to predict the leak amount through cracked concrete walls. The leakage through concrete cracks has been studied since 1972. Buss examined the flow rate of air through a pre-existing crack in a slab under air pressure. Rizkalla el al. initiated an experimental study for the leakage of prestressed concrete building segments under uniaxial and biaxial loadings to simulate the loading condition of containment buildings under an internal pressure. Recently, Salmon el al. initiated an experimental program for determining the leak rates in typical reinforced concrete shear walls subjected to beyond design basis earthquakes. This study investigates the cracking behavior of reinforced concrete containment wall elements under a uniaxial tension and addresses the outline of the leakage test for unlined containment wall elements

Alternative containment integrity test methods, an overview of possible techniques

International Nuclear Information System (INIS)

Spletzer, B.L.

1986-01-01

A study is being conducted to develop and analyze alternative methods for testing of containment integrity. The study is focused on techniques for continuously monitoring containment integrity to provide rapid detection of existing leaks, thus providing greater certainty of the integrity of the containment at any time. The study is also intended to develop techniques applicable to the currently required Type A integrated leakage rate tests. A brief discussion of the range of alternative methods currently being considered is presented. The methods include applicability to all major containment types, operating and shutdown plant conditions, and quantitative and qualitative leakage measurements. The techniques are analyzed in accordance with the current state of knowledge of each method. The bulk of the techniques discussed are in the conceptual stage, have not been tested in actual plant conditions, and are presented here as a possible future direction for evaluating containment integrity. Of the methods considered, no single method provides optimum performance for all containment types. Several methods are limited in the types of containment for which they are applicable. The results of the study to date indicate that techniques for continuous monitoring of containment integrity exist for many plants and may be implemented at modest cost

Method of detecting water leakage in radioactive waste containing vessel

International Nuclear Information System (INIS)

Ishioka, Hitoshi; Takao, Yoshiaki; Hayakawa, Kiyoshige.

1989-01-01

Lower level radioactive wastes formed upon operation of nuclear facilities are processed by underground storage. In this case, a plurality of drum cans packed with radioactive wastes are contained in a vessel and a water soluble dye material is placed at the inside of the vessel. The method of placing the water soluble dye material at the inside of the vessel includes a method of coating the material on the inner surface of the vessel and a method of mixing the material in sands to be filled between each of the drum cans. Then, leakage of water soluble dye material is detected when water intruding from the outside into the vessel is again leached out of the vessel, to detect the water leakage from the inside of the vessel. In this way, it is possible to find a water-invaded vessel before corrosion of the drum can by water intruded into the vessel and leakage of nuclides in the drum can. Accordingly, it is possible to apply treatment such as repair before occurrence of accident and can maintain the safety of radioactive water processing facilities. (I.S.)

Control room habitability assessment and in-leakage test for Korean NPP - 15510

International Nuclear Information System (INIS)

Song, D.S.; Lee, J.B.; Ha, S.J.; Seong, J.J.

2015-01-01

The assessment of control room habitability for Wolsung unit 1 was performed based on GL 2003-01 and Reg. Guide 1.197. The control room habitability program including Control Room Envelope (CRE) in-leakage test procedures, self assessment guidance, CRE boundary control program, CRE maintenance/sealing program was developed for Wolsung unit 1. The integrated CRE test was performed utilizing ASTM E741. There are two operating modes of pressurization and isolation for CRE ventilation test, and four tests were performed using each of the control room HVAC sub-trains. The control room HVAC system lineup of pressurization mode test was based upon a lineup that encompassed the design basis radiological analyses. The other control room HVAC system lineup of isolation mode test was based on an operation mode that considers toxic gas. The in-leakage testing was performed in accordance with CRE in-leakage test procedures. In the pressurization mode, measured unfiltered in-leakage rates for train A and train B were 0 CFM and 405 CFM respectively. In the isolation mode, measured unfiltered in-leakage rates for train A and train B were 1,739 CFM and 1,502 CFM, respectively. Maximum concentration of ammonia at the control room HVAC intake is calculated to be 0.027 g/m 3 (39 ppm), and satisfied the toxicity limit of 300 ppm. The test result shows that the measured unfiltered in-leakage is bounded by the regulatory criteria assumed in the design basis radiological analyses. (authors)

Early localization of containment leakage during an accident

International Nuclear Information System (INIS)

Pepin, P.; Chauliac, C.; Libmann, M.; Martinez, J.M.

1990-01-01

In case of an accident in a nuclear plant, checking the containment leaktightness would be a fundamental step for the diagnosis and prognosis of the radiological consequences. Significant help in this task can be provided by softwares. For that purpose, the French Atomic Energy Commission (CEA) is developing an expert system which can provide early in the accident a classification of the possible leakage paths and help understanding the necessary corrections which have to be undertaken by the utility. This software will be used at the Emergency Technical Center of the CEA. Its basic principles are described in this paper

ERROR REDUCTION IN DUCT LEAKAGE TESTING THROUGH DATA CROSS-CHECKS

Energy Technology Data Exchange (ETDEWEB)

ANDREWS, J.W.

1998-12-31

One way to reduce uncertainty in scientific measurement is to devise a protocol in which more quantities are measured than are absolutely required, so that the result is over constrained. This report develops a method for so combining data from two different tests for air leakage in residential duct systems. An algorithm, which depends on the uncertainty estimates for the measured quantities, optimizes the use of the excess data. In many cases it can significantly reduce the error bar on at least one of the two measured duct leakage rates (supply or return), and it provides a rational method of reconciling any conflicting results from the two leakage tests.

Atmospheric Tracer Depletion Testing for Unfiltered Air In-Leakage Determination at the Wolf Creek Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Sullivan, T. M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wilke, R. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roberts, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Vignato, G. J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2017-03-01

Atmospheric Tracer Depletion tests were conducted at the Wolf Creek Nuclear Power Plant to quantify the unfiltered in-leakage (UI) into the Control Room (CR), Control Building (CB), and Equipment Rooms (ER) at the Wolf Creek Nuclear Power Plant. Wolf Creek has two independent charcoal filter Emergency Ventilation Systems (EVS) that can be used to purify air entering the control building and control room. The Bravo System contains a filtration system in Room 1501 in the Auxiliary Building for the Control Room and another filtration system (FGK02B) on Elevation 2016 for the Control Building. The Alpha system contains a filtration system in Room 1512 in the Auxiliary Building for the Control Room and another filtration system (FGK02A) on Elevation 2016 for the Control Building. The Atmospheric Tracer Depletion (ATD) test is a technique to measure in-leakage using the concentration of perfluorocarbon compounds that have a constant atmospheric background. These levels are present in the Control Room and Control Building under normal operating conditions. When air is supplied by either of the EVS, most of the PFTS are removed by the charcoal filters. If the concentrations of the PFTs measured in protected areas are the same as the levels at the output of the EVS, the in-leakage of outside air into the protected area would be zero. If the concentration is higher in the protected area than at the output of the filter system, there is in-leakage and the in-leakage can be quantified by the difference. Sampling was performed using state-of-the-art Brookhaven Atmospheric Tracer Samplers (BATS) air sampling equipment and analysis performed on Brookhaven National Laboratory (BNL) dedicated PFT analytical systems. In the Alpha test two tracers PMCH and mcPDCH were used to determine in-leakage into the control building. The analytical system was tuned to maximize sensitivity after initial analysis of the Alpha test. The increased sensitivity permitted accurate quantification of

Atmospheric Tracer Depletion Testing for Unfiltered Air In-Leakage Determination at the Wolf Creek Nuclear Power Plant

Energy Technology Data Exchange (ETDEWEB)

Sullivan, T. M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wilke, R. J. [Brookhaven National Lab. (BNL), Upton, NY (United States); Roberts, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Vignato, G. J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

2017-04-01

Atmospheric Tracer Depletion tests were conducted at the Wolf Creek Nuclear Power Plant to quantify the unfiltered in-leakage (UI) into the Control Room (CR), Control Building (CB), and Equipment Rooms (ER) at the Wolf Creek Nuclear Power Plant. Wolf Creek has two independent charcoal filter Emergency Ventilation Systems (EVS) that can be used to purify air entering the control building and control room. The Bravo System contains a filtration system in Room 1501 in the Auxiliary Building for the Control Room and another filtration system (FGK02B) on Elevation 2016 for the Control Building. The Alpha system contains a filtration system in Room 1512 in the Auxiliary Building for the Control Room and another filtration system (FGK02A) on Elevation 2016 for the Control Building.The Atmospheric Tracer Depletion (ATD) test is a technique to measure in-leakage using the concentration of perfluorocarbon compounds that have a constant atmospheric background. These levels are present in the Control Room and Control Building under normal operating conditions. When air is supplied by either of the EVS, most of the PFTS are removed by the charcoal filters. If the concentrations of the PFTs measured in protected areas are the same as the levels at the output of the EVS, the in-leakage of outside air into the protected area would be zero. If the concentration is higher in the protected area than at the output of the filter system, there is in-leakage and the in-leakage can be quantified by the difference.Sampling was performed using state-of-the-art Brookhaven Atmospheric Tracer Samplers (BATS) air sampling equipment and analysis performed on Brookhaven National Laboratory (BNL) dedicated PFT analytical systems. In the Alpha test two tracers PMCH and mcPDCH were used to determine in-leakage into the control building. The analytical system was tuned to maximize sensitivity after initial analysis of the Alpha test. The increased sensitivity permitted accurate quantification of five

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

Artificial-Crack-Behavior Test Evaluation of the Water-Leakage Repair Materials Used for the Repair of Water-Leakage Cracks in Concrete Structures

OpenAIRE

Soo-Yeon Kim; Sang-Keun Oh; Byoungil Kim

2016-01-01

There are no existing standard test methods at home and abroad that can verify the performance of water leakage repair materials, and it is thus very difficult to perform quality control checks in the field of water leakage repair. This study determined that the key factors that have the greatest impact on the water leakage repair materials are the micro-behaviors of cracks, and proposed an artificial-crack-behavior test method for the performance verification of the repair materials. The per...

Analyzing containment leakage from a sodium fire by the response surface method

International Nuclear Information System (INIS)

Person, L.W.

1978-01-01

The SPOOL-FIRE code has been used with the response surface method and a Monte Carlo simulation to study sodium fire accidents. The study provides a simple method of estimating the radioactive release via containment leakage; the sensitivity of the output consequences to the variations in the input parameters is also presented

Integrated leak rate testing of the fast flux test facility reactor containment building

International Nuclear Information System (INIS)

James, E.B.; Farabee, O.A.; Bliss, R.J.

1978-01-01

The initial Integrated Leak Rate Test (ILRT) of the Fast Flux Test Facility containment building was performed from May 27 to June 2, 1978. The test was conducted in air with systems vented and with the containment recirculating coolers in operation. 10 psig and 5 psig tests were run using the absolute pressure test method. The measured leakage rates were .033% Vol/24 hr. and -.0015% Vol/24 hrs. respectively. Subsequent verification tests at both 10 psig and 5 psig proved that the test equipment was operating properly and it was sensitive enough to detect leaks at low pressures. This ILRT was performed at a lower pressure than any previous ILRT on a reactor containment structure in the United States. While the initial design requirements for ice condenser containments called for a part pressure test at 6 psig, the tests were waived due to the apparent statistical problems of data analysis and the repeatability of the data itself at such low pressure. In contrast to this belief, both the 5 and 10 psig ILRT's were performed in a successful manner at FFTF

Leakage potential through mechanical penetrations in a severe accident environment

International Nuclear Information System (INIS)

Koenig, L.N.

1986-01-01

This paper reviews the findings of an ongoing program, Integrity of Containment Penetrations Under Severe Accident Loads. The program is concerned with the leakage modes as well as the magnitude of leakage through mechanical penetrations in a containment building subject to a severe accident. Seal and gasket tests are used to evaluate the effect of radiation aging, thermal aging, seal geometry, and seal squeeze on seals and gaskets subjected to a hypothesized severe accident. The effects on leakage of the structural response of equipment hatches, personnel airlocks, and drywell heads subjected to severe accident pressures are studied by experiments and analyses. The data gathered during this program will be used to develop methodologies for predicting leakage

LMFBR technology. FFTF cover-gas leakage calculation

International Nuclear Information System (INIS)

Deboi, H.

1974-01-01

The FFTF LMFBR is intended to have a near zero release of radioactive gases during normal reactor operation with 1% failed fuel. This report presents calculations which provide an approximation of these cover gas leakages. Data from ongoing static and dynamic seal leak tests at AI are utilized. Leakage through both elastomeric and metallic seals in all sub-assemblies and penetrations comprising the reactor cover gas containment during reactor operation system are included

N13 - based reactor coolant pressure boundary leakage system

International Nuclear Information System (INIS)

Dissing, E.; Marbaeck, L.; Sandell, S.; Svansson, L.

1980-05-01

A system for the monitoring of leakage of coolant from the reactor coolant pressure boundary and auxiliary systems to the reactor containment, based on the detection of the N13 content in the atmosphere, has been tested. N13 is produced from the oxyegen of the reactor water via the recoil photon nuclear process H1 + 016 + He4. The generation of N13 is therefore independent of fuel element leakage and of the corrosion product content in the water. In the US AEC regulatory guide 1.45 has a leakage increase of 4 liter/ min been suggested as the response limit. The experiments carried out in Ringhals indicate, that with the accomplishment of minor improvements in the installation, a 4 liter/min leakage to the containment will give rise to a signal with a random error range of +- 0.25 liter/min, 99.7 % confidence level. (author)

Preventive testing and leakage detection in pipe-lines of steam condensers and generators of a PWR type reactor

International Nuclear Information System (INIS)

Canalini, A.; Carvalho, N.C. de

1985-01-01

The non-destructive methods: Spum, Helium and Hydrostatic used in leakage detection in condenser pipelines for PWR type reactors are presented. The time, costs, sensitivity, resources necessary and personnel development factors are considered to choose adequated method, in function of nuclear power plant conditions. The leakage tests are applied in pressurized systems or vacuum. Eddy Current testing is used in condensers and steam generators aiming to avoid leakage in these equipments. The spume testing for leakage detection in condenser pipelines - which operation - and hydrostatic testing for leakage detection through reaming with shutdown - were most efficients. The Helium testing applied in pressurized systems or submitted to vacuum systems presented satisfactory results. The Eddy Current testing in condenser and steam generator pipelines reached desired objective, reducing leakage in the first and preserving the integrity in the second. (M.C.K.) [pt

A harmonic pulse testing method for leakage detection in deep subsurface storage formations

Science.gov (United States)

Sun, Alexander Y.; Lu, Jiemin; Hovorka, Susan

2015-06-01

Detection of leakage in deep geologic storage formations (e.g., carbon sequestration sites) is a challenging problem. This study investigates an easy-to-implement frequency domain leakage detection technology based on harmonic pulse testing (HPT). Unlike conventional constant-rate pressure interference tests, HPT stimulates a reservoir using periodic injection rates. The fundamental principle underlying HPT-based leakage detection is that leakage modifies a storage system's frequency response function, thus providing clues of system malfunction. During operations, routine HPTs can be conducted at multiple pulsing frequencies to obtain experimental frequency response functions, using which the possible time-lapse changes are examined. In this work, a set of analytical frequency response solutions is derived for predicting system responses with and without leaks for single-phase flow systems. Sensitivity studies show that HPT can effectively reveal the presence of leaks. A search procedure is then prescribed for locating the actual leaks using amplitude and phase information obtained from HPT, and the resulting optimization problem is solved using the genetic algorithm. For multiphase flows, the applicability of HPT-based leakage detection procedure is exemplified numerically using a carbon sequestration problem. Results show that the detection procedure is applicable if the average reservoir conditions in the testing zone stay relatively constant during the tests, which is a working assumption under many other interpretation methods for pressure interference tests. HPT is a cost-effective tool that only requires periodic modification of the nominal injection rate. Thus it can be incorporated into existing monitoring plans with little additional investment.

Thermal tests on UF6 containers and valves modelisation and extrapolation on real fire situations

International Nuclear Information System (INIS)

Duret, B.; Warniez, P.

1988-12-01

From realistic tests on containers or on valves, we propose a modelisation which we apply to 3 particular problems: resistance of a 48 Y containers, during a fire situation. Influence of the presence of a valve. Evaluation of a leakage through a breach, mechanically created before a fire

10 CFR 32.103 - Schedule D-prototype tests for ice detection devices containing strontium-90.

Science.gov (United States)

2010-01-01

... water and the strontium-90 shall be considered leakage. (e) Observations. After each of the tests... 10 Energy 1 2010-01-01 2010-01-01 false Schedule D-prototype tests for ice detection devices... § 32.103 Schedule D—prototype tests for ice detection devices containing strontium-90. An applicant for...

Containment performance of transportable storage casks at 9m drop test

Energy Technology Data Exchange (ETDEWEB)

Tobita, H. [Hitachi Zosen Corp., Osaka (Japan); Araki, K. [Hitachi Zosen Diesel and Engineering Co., Ltd., Tokyo (Japan)

2004-07-01

Spent fuel transportable storage casks usually have a double lid closure system, which consists of primary and secondary lids, and gaskets, to keep the containment function during transportation and storage, and to monitor a leakage or containment function during storage. Metal gasket is planning to be used not only during storage but transportation of both before and after storage. As metal gasket will degrade its containment function by creep during storage period of 50 years, relative displacement such as opening and slide displacement between the flange of the containment vessel and the lid should be restricted to a small range. To maintain the containment performance, we provisionally adopted the maximum opening limit of 0.1mm and the maximum slide displacement limit of 3.0mm in the full-scale cask design based on the report of the fundamental experiment on the metal gasket which examines the relation between leakage rate and sealing gap. The purpose of this study is to analyse the behaviour of the sealed parts (lid and vessel body) under 9m-drop impact test conditions and to establish some analytical method to evaluate this behaviour. In this study, the drop test of 1/3scale model of Hitz-B69 cask with the double lids closure system was carried out, the behaviours of the seal part were measured by displacement sensors, and they were compared with the result of the numerical analysis carried out separateley.

Detection Test for Leakage of CO2 into Sodium Loop

International Nuclear Information System (INIS)

Park, Sun Hee; Wi, Myung-Hwan; Min, Jae Hong

2015-01-01

This report is about the facility for the detection test for leakage of CO 2 into sodium loop. The facility for the detection test for leakage of CO 2 into sodium loop was introduced. The test will be carried out. Our experimental results are going to be expected to be used for approach methods to detect CO 2 leaking into sodium in heat exchangers. A sodium-and-carbon dioxide (Na-CO 2 ) heat exchanger is one of the key components for the supercritical CO 2 Brayton cycle power conversion system of sodium-cooled fast reactors (SFRs). A printed circuit heat exchanger (PCHE) is considered for the Na-CO 2 heat exchanger, which is known to have potential for reducing the volume occupied by the exchangers compared to traditional shell-and-tube heat exchangers. Among various issues about the Na- CO 2 exchanger, detection of CO 2 leaking into sodium in the heat exchanger is most important thing for its safe operation. It is known that reaction products from sodium and CO 2 such as sodium carbonate (Na 2 CO 3 ) and amorphous carbon are hardly soluble in sodium, which cause plug sodium channels. Detection technique for Na 2 CO 3 in sodium loop has not been developed yet. Therefore, detection of CO 2 and CO from reaction of sodium and CO 2 are proper to detect CO 2 leakage into sodium loop

Nuclear power plant prestressed concrete containment vessel structure monitoring during integrated leakage rate test using three kinds of fiber optic sensors

Science.gov (United States)

Liao, Kaixing; Li, Jinke; Kong, Xianglong; Sun, Changsen; Zhao, Xuefeng

2017-04-01

After years of operation, the safety of the prestressed concrete containment vessel (PCCV) structure of Nuclear Power Plant (NPP) is an important aspect. In order to detect the strength degradation and the structure deformation, several sensors such as vibrating wire strain gauge, invar wires and pendulums were installed in PCCV. However, the amounts of sensors above are limited due to the cost. Due to the well durability of fiber optic sensors, three kinds of fiber optic sensors were chosen to install on the surface of PCCV to monitor the deformation during Integrated Leakage Rate Test (ILRT). The three kinds of fiber optic sensors which had their own advantages and disadvantages are Fiber Bragg Grating (FBG), white light interferometry (WLI) and Brillouin Optical Time Domain Analysis (BOTDA). According to the measuring data, the three fiber optic sensors worked well during the ILRT. After the ILRT, the monitoring strain was recoverable thus the PCCV was still in the elastic stage. If these three kinds of fiber optic sensors are widely used in the PCCV, the unusual deformations are easier to detect. As a consequence, the three fiber optic sensors have good potential in the structure health monitoring of PCCV.

NEK containment integrated leak rate test at full pressure

International Nuclear Information System (INIS)

Skaler, F.; Planinc, V.; Gregoric, D.; Cicvaric, D.

1999-01-01

NPP Krsko is a Pressure Water Reactor (PWR) Plant which has four barriers to prevent release of radioactive fission products. These four barriers are following: Fuel itself, Fuel Clad, Reactor Coolant System and Containment Building. Containment is the last barrier which can prevent release of fission product when other barriers have been already broken. To find out the real condition of containment vessel and to prove its ability of withstanding increased parameters during accident we have to perform Containment Integrated Leak Rate Test at least three times in every ten years of operation. CILRT 1999 in NPP Krsko was completely performed following regulation of 10CFR50 App. J Option A and ANSI/ANS 56.8-1987. The main goal of CILRT is to prove that the leakage of containment pathways and wall structures are within limits prescribed in Technical Specifications by pressurization of containment building above peak accident pressure Pa and measuring the mass changes of air using Ideal Gas Law.(author)

Air leakage test of reactor hall using tracer technique

International Nuclear Information System (INIS)

Yang Yanqiu; Yang Liang; Yang Tongzai

2011-01-01

The leakage ratios of three related reactor halls were tested by sulfur hexafluoride gaseous tracer technique. Moreover, the accumulation intensities of leak gas and its retention time in some important working rooms, the crossroads of corridors and anteroom of the building were detected. The results show that the air leakage ratios of the three reactor halls are (7.30±0.16) x 10 -4 , (1.88±0.12) x 10 -4 and (2.07±0.07) x 10 -4 h -1 . The leak gas accumulates in all the detected working rooms fast, and the retention time to various rooms is about 5 h. The heaviest intensities are in the clothes change rooms on the first floor. However, the retention time to the crossroads and the anteroom is about 10 h, and the accumulation intensities are much small. (authors)

Performance of containment of Indian PHWR

International Nuclear Information System (INIS)

Mohan, Nalini; Ghadge, S.G.; Bajaj, S.S.

2006-01-01

This paper summarizes the various requirements and activities relevant to the testing of containment system of Indian Pressurized Heavy Water Reactor (PHWR). All Indian PHWR containments are constructed from concrete either reinforced or prestressed or a combination of both and lined with polymeric coating based on Epoxy or Vinyl in order to achieve the leak tightness necessary from the radiological considerations following an accident. The current concept includes a complete double containment (except the base raft) extended to all penetrations and some of the pipings (those open to the containment atmosphere). The primary containment fitted with a passive pressure suppression system is enveloped in the secondary containment (confinement) where slight vacuum is maintained during normal operation as well as post accident condition. The Integrated leakage Rate Test (ILRT) conducted so far on the containment indicate that the overall leakages from the containment are lower than those necessary to meet the radiological limits following a postulated accident and interception of leakages by secondary containment as per design. The details of the, tests, repairs carried out and observations are given in this paper. The experience of ILRT also indicate improvement in leak tightness in many areas. (author)

Effect of flow leakage on the benchmarking of FLOWTRAN with Mark-22 mockup flow excursion test data from Babcock and Wilcox

International Nuclear Information System (INIS)

Chen, Kuo-Fu.

1992-10-01

This report presents a revised analysis of the Babcock and Wilcox (B and W) downflow flow excursion tests that accounts for leakage between flow channels in the test assembly. Leak rates were estimated by comparing results from the downflow tests with those for upflow tests conducted using an identical assembly with some minor modifications. The upflow test assembly did not contain leaks. This revised analyses shows that FLOWTRAN with the SRS working criterion conservatively predicts onset of flow instability without using a local peaking factor to model heat transfer variations near the ribs

Observations on analysis, testing and failure of prestressed concrete containments

International Nuclear Information System (INIS)

Murray, D.W.

1984-01-01

The paper reviews the mechanics which indicate that a bursting failure with large energy release is the failure mechanism to be expected from ductile lined containment structures pressurized to failure. It reviews a study which shows that, because of leakage, this is not the case for unlined prestressed containments. It argues that current practice, since it does not specifically address the bursting failure problem for lined prestressed containments, is inadequate to ensure that this type of failure could not occur. It concludes that, in view of the inadequacy of the current state-of-the-art to predict leakage from lined structures, the logical remedy is to eliminate all possibility of bursting failure by making provision for venting of containments. (orig.)

Final Report: Part 1. In-Place Filter Testing Instrument for Nuclear Material Containers. Part 2. Canister Filter Test Standards for Aerosol Capture Rates.

Energy Technology Data Exchange (ETDEWEB)

Brown, Austin Douglas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Runnels, Joel T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moore, Murray E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reeves, Kirk Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-11-02

A portable instrument has been developed to assess the functionality of filter sand o-rings on nuclear material storage canisters, without requiring removal of the canister lid. Additionally, a set of fifteen filter standards were procured for verifying aerosol leakage and pressure drop measurements in the Los Alamos Filter Test System. The US Department of Energy uses several thousand canisters for storing nuclear material in different chemical and physical forms. Specialized filters are installed into canister lids to allow gases to escape, and to maintain an internal ambient pressure while containing radioactive contaminants. Diagnosing the condition of container filters and canister integrity is important to ensure worker and public safety and for determining the handling requirements of legacy apparatus. This report describes the In-Place-Filter-Tester, the Instrument Development Plan and the Instrument Operating Method that were developed at the Los Alamos National Laboratory to determine the “as found” condition of unopened storage canisters. The Instrument Operating Method provides instructions for future evaluations of as-found canisters packaged with nuclear material. Customized stainless steel canister interfaces were developed for pressure-port access and to apply a suction clamping force for the interface. These are compatible with selected Hagan-style and SAVY-4000 storage canisters that were purchased from NFT (Nuclear Filter Technology, Golden, CO). Two instruments were developed for this effort: an initial Los Alamos POC (Proof-of-Concept) unit and the final Los Alamos IPFT system. The Los Alamos POC was used to create the Instrument Development Plan: (1) to determine the air flow and pressure characteristics associated with canister filter clogging, and (2) to test simulated configurations that mimicked canister leakage paths. The canister leakage scenarios included quantifying: (A) air leakage due to foreign material (i.e. dust and hair

Design and construction of a large reinforced concrete containment model to be tested to failure

International Nuclear Information System (INIS)

Ucciferro, J.J.; Horschel, D.S.

1987-01-01

The US Nuclear Regulatory Commission is investigating the performance of LWR containments subjected to severe accidents. This work is being performed by the Containment Integrity Division at Sandia National Laboratories (Sandia). The latest research effort involves the testing of a 1/6-scale reinforced concrete containment model. The containment, which was designed and constructed by United Engineers and Constructors, is the largest and most complex model of its kind. The design and construction of the containment model are the subject of this paper. The objective of the containment model tests is to generate data that can be used to qualify methods for reliably predicting the response of LWR containment buildings to severe accident loads. The data recorded during testing include deformations and leakage past sealing surfaces, as well as strains and displacements of the containment shell

Field demonstration of CO2 leakage detection in potable aquifers with a pulselike CO2-release test.

Science.gov (United States)

Yang, Changbing; Hovorka, Susan D; Delgado-Alonso, Jesus; Mickler, Patrick J; Treviño, Ramón H; Phillips, Straun

2014-12-02

This study presents two field pulselike CO2-release tests to demonstrate CO2 leakage detection in a shallow aquifer by monitoring groundwater pH, alkalinity, and dissolved inorganic carbon (DIC) using the periodic groundwater sampling method and a fiber-optic CO2 sensor for real-time in situ monitoring of dissolved CO2 in groundwater. Measurements of groundwater pH, alkalinity, DIC, and dissolved CO2 clearly deviated from their background values, showing responses to CO2 leakage. Dissolved CO2 observed in the tests was highly sensitive in comparison to groundwater pH, DIC, and alkalinity. Comparison of the pulselike CO2-release tests to other field tests suggests that pulselike CO2-release tests can provide reliable assessment of geochemical parameters indicative of CO2 leakage. Measurements by the fiber-optic CO2 sensor, showing obvious leakage signals, demonstrated the potential of real-time in situ monitoring of dissolved CO2 for leakage detection at a geologic carbon sequestration (GCS) site. Results of a two-dimensional reactive transport model reproduced the geochemical measurements and confirmed that the decrease in groundwater pH and the increases in DIC and dissolved CO2 observed in the pulselike CO2-release tests were caused by dissolution of CO2 whereas alkalinity was likely affected by carbonate dissolution.

Numerical investigation of the leakage behaviour of reinforced concrete walls

International Nuclear Information System (INIS)

Christoph Niklasch; Laurent Coudert; Gregory Heinfling; Chantal Hervouet; Benoit Masson; Nico Herrmann; Lothar Stempniewski

2005-01-01

Full text of publication follows: For the verification of nuclear power plant safety, the leakage behaviour of the containment walls is of decisive importance. Extreme temperatures well over the water boiling temperature accompanied by high internal pressures can occur during an severe accident. In case of cracks through the entire thickness of the containment wall, an air-steam-water mixture may be released. In order to improve the knowledge of the leakage behaviour through cracks during such abnormal occurrences an experimental setup was developed at IfMB and several tests with different parameters were performed. The details of the experimental facility and the performed tests will be described in a separate paper. To improve the understanding of the behaviour of the tested wall elements during the tests numerical simulations of the performed leakage experiments are necessary. Reliable numerical tools provide a basis for the transfer of the leakage behaviour from the tested specimens to the behaviour of whole containment structures. To address the task of developing tools for the numerical simulation of the leakage behaviour of reinforced containment structures, EDF and IfMB decided to cooperate. During this cooperation two different numerical approaches had been made basing on existing tools and models of EDF and IfMB. In the following sections a short overview about the two different models will be given. For the numerical investigation of the leakage phenomena IfMB used the commercial Finite-Element- Program ADINA with ADINA's capability to solve coupled fluid-structure-interaction (FSI) problems. For the investigation of the moving of the specimen and the change of the crack profiles during the tests, it is important to take into account the heating of the specimen by the fluid flowing through the cracks. This is done by an iterative calculation of the fluid model and the structural model of the specimen. The thermo-dynamic boundary conditions representing

The EPR (European Pressurized Water Reactor) containment - concept, testing of leakage behaviour, FRP liner

Energy Technology Data Exchange (ETDEWEB)

Touret, J.P. [EDF SEPTEN, Villeurbanne (France); Liersch, G. [Bayernwerk Kerenergie GmbH, Muenchen (Germany); Danisch, R. [Siemens AG, KWU NAD, Erlangen (Germany)

2001-07-01

The Basic Design of the EPR has now been completed. The containment plays a major safety-related role with respect to protection of the environment against radioactive releases. The EPR features a double (steel-reinforced concrete/prestressed concrete) containment design, with the inner containment coated additionally with a fibreglass-reinforced plastic (FRP) liner in certain areas. This means that containment leaktightness is provided mainly by the prestressed concrete and the FRP liner in the event of a postulated accident. The numerous findings of the tests carried out so far in both France and Germany are summarized. (orig.) [German] Das Basic Design fuer den EPR ist fertiggestellt. Entscheidend fuer eine Realisierung wird neben der politischen Akzeptanz vor allem die Wettbewerbsfaehigkeit mit anderen Energietraegern sein. Im EPR-Projekt wird der hohe Sicherheitsstandard der heutigen Kernkraftwerke in Deutschland und Frankreich ergaenzt, indem zusaetzlich technische Massnahmen ergriffen werden, um die Konsequenzen beim unterstellten Versagen aller sicherheitstechnischen Einrichtungen mit der Folge eines postulierten Niederschmelzen des Kerns technisch zu beherrschen. (orig.)

Using electrolyte leakage tests to determine lifting windows and detect tissue damage

Science.gov (United States)

Richard W. Tinus

2002-01-01

Physiological testing is rapidly coming into use as a means to determine the condition of nursery stock and predict how it will respond to treatment or use. One such test, the electrolyte leakage test, can be used to measure cold hardiness and detect tissue damage. The principle of this test is that when cell membranes are damaged, electrolytes leak out into the water...

Cochlin-tomoprotein (CTP) detection test identified perilymph leakage preoperatively in revision stapes surgery.

Science.gov (United States)

Kataoka, Yuko; Ikezono, Tetsuo; Fukushima, Kunihiro; Yuen, Koji; Maeda, Yukihide; Sugaya, Akiko; Nishizaki, Kazunori

2013-08-01

Perilymphatic fistula (PLF) is defined as an abnormal leakage between perilymph from the labyrinth to the middle ear. Symptoms include hearing loss, tinnitus, and vertigo. The standard mode of PLF detection is intraoperative visualization of perilymph leakage and fistula, which ostensibly confirms the existence of PLF. Other possible methods of diagnosis include confirmation of pneumolabyrinth via diagnostic imaging. Recently, a cochlin-tomoprotein (CTP) detection test has been developed that allows definitive diagnosis of PLF-related hearing loss. We report the case of a 45-year-old man who presented with right-sided tinnitus, hearing loss, and dizziness 30 years after stapes surgery. Middle ear lavage was performed after myringotomy. A preoperative diagnosis of PLF was reached using the CTP detection test. Intraoperative observations included a necrotic long process of the incus, displaced wire piston, and fibrous tissue in the oval window. Perilymph leakage was not evident. The oval window was closed with fascia, and vertigo disappeared within 2 weeks postoperatively. When PLF is suspected after stapes surgery, the CTP detection test can be a useful, highly sensitive, and less invasive method for preoperative diagnosis. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Predicting Envelope Leakage in Attached Dwellings

Energy Technology Data Exchange (ETDEWEB)

Faakye, O. [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Arena, L. [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Griffiths, D. [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

2013-07-01

The most common method for measuring air leakage is to use a single blower door to pressurize and/or depressurize the test unit. In detached housing, the test unit is the entire home and the single blower door measures air leakage to the outside. In attached housing, this 'single unit', 'total', or 'solo' test method measures both the air leakage between adjacent units through common surfaces as well air leakage to the outside. Measuring and minimizing this total leakage is recommended to avoid indoor air quality issues between units, reduce energy losses to the outside, reduce pressure differentials between units, and control stack effect. However, two significant limitations of the total leakage measurement in attached housing are: for retrofit work, if total leakage is assumed to be all to the outside, the energy benefits of air sealing can be significantly over predicted; for new construction, the total leakage values may result in failing to meet an energy-based house tightness program criterion. The scope of this research is to investigate an approach for developing a viable simplified algorithm that can be used by contractors to assess energy efficiency program qualification and/or compliance based upon solo test results.

Radioactivity leakage monitoring system

International Nuclear Information System (INIS)

Nakajima, Takuichiro; Noguchi, Noboru.

1982-01-01

Purpose: To obtain a device for detecting the leakage ratio of a primary coolant by utilizing the variation in the radioactivity concentration in a reactor container when the coolant is leaked. Constitution: A measurement signal is produced from a radioactivity measuring instrument, and is continuously input to a malfunction discriminator. The discriminator inputs a measurement signal to a concentration variation discriminator when the malfunction is recognized and simultaneously inputs a measurement starting time from the inputting time to a concentration measuring instrument. On the other hand, reactor water radioactivity concentration data obtained by sampling the primary coolant is input to a concentration variation computing device. A comparator obtains the ratio of the measurement signal from the measuring instrument and the computed data signal from the computing device at the same time and hence the leakage rate, indicates the average leakage rate by averaging the leakage rate signals and also indicates the total leakage amount. (Yoshihara, H.)

Procedure to carry out leakage test in beta radiation sealed sources emitters of 90Sr/90Y

International Nuclear Information System (INIS)

Alvarez R, J. T.

2010-09-01

In the alpha-beta room of the Secondary Laboratory of Dosimetric Calibration of the Metrology Department of Ionizing Radiations ophthalmic applicators are calibrated in absorbed dose terms in water D w ; these applicators, basically are emitter sealed sources of pure beta radiation of 90 Sr / 90 Y. Concretely, the laboratory quality system indicates to use the established procedure for the calibration of these sources, which establishes the requirement of to carry out a leakage test, before to calibrate the source. However, in the Laboratory leakage test certificates sent by specialized companies in radiological protection services have been received, in which are used gamma spectrometry equipment s for beta radiation leakage tests, since it is not reliable to detect pure beta radiation with a scintillating detector with NaI crystal, (because it could detect the braking radiation produced in the detector). Therefore the Laboratory has had to verify the results of the tests with a correct technique, with the purpose of determining the presence of sources with their altered integrity and radioactive material leakage. The objective of this work is to describe a technique for beta activity measurement - of the standard ISO 7503, part 1 (1988) - and its application with a detector Gm plane (type pankage) in the realization of leakage tests in emitter sources of pure beta radiation, inside the mark of quality assurance indicated by the report ICRU 76. (Author)

Detection Test for Leakage of CO{sub 2} into Sodium Loop

Energy Technology Data Exchange (ETDEWEB)

Park, Sun Hee; Wi, Myung-Hwan; Min, Jae Hong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2015-10-15

This report is about the facility for the detection test for leakage of CO{sub 2} into sodium loop. The facility for the detection test for leakage of CO{sub 2} into sodium loop was introduced. The test will be carried out. Our experimental results are going to be expected to be used for approach methods to detect CO{sub 2} leaking into sodium in heat exchangers. A sodium-and-carbon dioxide (Na-CO{sub 2}) heat exchanger is one of the key components for the supercritical CO{sub 2} Brayton cycle power conversion system of sodium-cooled fast reactors (SFRs). A printed circuit heat exchanger (PCHE) is considered for the Na-CO{sub 2} heat exchanger, which is known to have potential for reducing the volume occupied by the exchangers compared to traditional shell-and-tube heat exchangers. Among various issues about the Na- CO{sub 2} exchanger, detection of CO{sub 2} leaking into sodium in the heat exchanger is most important thing for its safe operation. It is known that reaction products from sodium and CO{sub 2} such as sodium carbonate (Na{sub 2}CO{sub 3}) and amorphous carbon are hardly soluble in sodium, which cause plug sodium channels. Detection technique for Na{sub 2}CO{sub 3} in sodium loop has not been developed yet. Therefore, detection of CO{sub 2} and CO from reaction of sodium and CO{sub 2} are proper to detect CO{sub 2} leakage into sodium loop.

Development of monitoring system using acoustic emission for detection of helium gas leakage for primary cooling system and flow-induced vibration for heat transfer tube of heat exchangers for the High Temperature Engineering Test Reactor (HTTR)

International Nuclear Information System (INIS)

Tachibana, Yukio; Kunitomi, Kazuhiko; Furusawa, Takayuki; Shinozaki, Masayuki; Satoh, Yoshiyuki; Yanagibashi, Minoru

1998-10-01

The High Temperature Engineering Test Reactor (HTTR) uses helium gas for its primary coolant, whose leakage inside reactor containment vessel is considered in design of the HTTR. It is necessary to detect leakage of helium gas at an early stage so that total amount of the leakage should be as small as possible. On the other hand, heat transfer tubes of heat exchangers of the HTTR are designed not to vibrate at normal operation, but the flow-induced vibration is to be monitored to provide against an emergency. Thus monitoring system of acoustic emission for detection of primary coolant leakage and vibration of heat transfer tubes was developed and applied to the HTTR. Before the application to the HTTR, leakage detection test was performed using 1/4 scaled model of outer tube of primary concentric hot gas duct. Result of the test covers detectable minimum leakage rate and effect of difference in gas, pressure, shape of leakage path and distance from the leaking point. Detectable minimum leakage rate was about 5 Ncc/sec. The monitoring system is promising in leakage detection, though countermeasure to noise is to be needed after the HTTR starts operating. (author)

Heat loss and fluid leakage tests of the ROSA-III facility

International Nuclear Information System (INIS)

Suzuki, Mitsuhiro; Tasaka, Kanji; Shiba, Masayoshi

1981-12-01

The report presents characteristic test results about the steady state heat loss, one of the inherent characteristics of the ROSA-III test facility. The steady state heat loss tests were conducted at five different temperature conditions between 111 0 C and 290 0 C . Net heat loss rates were obtained by estimating the electric power supplied to the core, heat input from the recirculation pumps and steam leakage rate. The heat loss characteristics have important contribution to analyses of the ROSA-III small break tests. A following simple relation was obtained between the net heat loss rate Q*sub(HL) (kJ/s) (*: radical) of the ROSA-III facility and the temperature difference ΔT ( 0 C) between the fluid temperature of the system and the room temperature, Q*sub(HL) = 0.56 x ΔT. (*: radical) And the steam leak flow at normal operating condition of the ROSA-III test, (P = 7.2 MPa) was obtained as 8.9 x 10 -3 kg/s and corresponding steam leakage energy as 10.5 kJ/s. The heat input from the recirculation pumps was indirectly estimated under a constant speed by assuming the heat input was equal to the brake horce power of the pumps. (author)

Coolant leakage detecting device

International Nuclear Information System (INIS)

Yamauchi, Kiyoshi; Kawai, Katsunori; Ishihara, Yoshinao.

1995-01-01

The device of the present invention judges an amount of leakage of primary coolants of a PWR power plant at high speed. Namely, a mass of coolants contained in a pressurizer, a volume controlling tank and loop regions is obtained based on a preset relational formula and signals of each of process amount, summed up to determine the total mass of coolants for every period of time. The amount of leakage for every period of time is calculated by a formula of Karman's filter based on the total mass of the primary coolants for every predetermined period of time, and displays it on CRT. The Karman's filter is formed on every formula for several kinds of states formed based on the preset amount of the leakage, to calculate forecasting values for every mass of coolants. An adaptable probability for every preset leakage amount is determined based on the difference between the forecast value and the observed value and the scattering thereof. The adaptable probability is compared with a predetermined threshold value, which is displayed on the CRT. This device enables earlier detection of leakage and identification of minute leakage amount as compared with the prior device. (I.S.)

The scheme optimization and management innovation for the first containment integrated in-service test of nuclear power plant

International Nuclear Information System (INIS)

Wang Haiwei; Yang Gang

2014-01-01

The containment integrated test is a large-scale, high risk and very difficult test in pressurized water reactor nuclear power plants. By simulating peak pressure inside the containment in DESIGN-BASIS accident conditions, measuring the total leakage rate of the containment with the peak pressure, and implementing the structure inspection test on several pressure levels, the containment's performance can be verified. Containment integrated test is an important witness point supervised by NNSA. The test results crucially decide the reactor to be started or not. The containment integrated test in 301 overhaul is the first in-service test of Unit 3. By the experience of the same 6 former tests in Qinshan Second Nuclear Power Plant and the feedback from other plants, the test scheme get more scientific and the organization management more standardized. This article discusses the containment integrated test in 301 overhaul and summarizes the experience to provide some references for the following containment integrated tests in the future. (authors)

ATR confinement leakage determination

International Nuclear Information System (INIS)

Kuan, P.; Buescher, B.J.

1998-01-01

The air leakage rate from the Advanced Test Reactor (ATR) confinement is an important parameter in estimating hypothesized accidental releases of radiation to the environment. The leakage rate must be determined periodically to assure that the confinement has not degraded with time and such determination is one of the technical safety requirements of ATR operation. This paper reviews the methods of confinement leakage determination and presents an analysis of leakage determination under windy conditions, which can complicate the interpretation of the determined leakage rates. The paper also presents results of analyses of building air exchange under windy conditions. High wind can enhance air exchange and this could increase the release rates of radioisotopes following an accident

Over-pressure test on BARCOM pre-stressed concrete containment

Energy Technology Data Exchange (ETDEWEB)

Parmar, R.M.; Singh, Tarvinder; Thangamani, I.; Trivedi, Neha; Singh, Ram Kumar, E-mail: rksingh@barc.gov.in

2014-04-01

Bhabha Atomic Research Centre (BARC), Trombay has organized an International Round Robin Analysis program to carry out the ultimate load capacity assessment of BARC Containment (BARCOM) test model. The test model located in BARC facilities Tarapur; is a 1:4 scale representation of 540 MWe Pressurized Heavy Water Reactor (PHWR) pre-stressed concrete inner containment structure of Tarapur Atomic Power Station (TAPS) unit 3 and 4. There are a large number of sensors installed in BARCOM that include vibratory wire strain gauges of embedded and spot-welded type, surface mounted electrical resistance strain gauges, dial gauges, earth pressure cells, tilt meters and high resolution digital camera systems for structural response, crack monitoring and fracture parameter measurement to evaluate the local and global behavior of the containment test model. The model has been tested pneumatically during the low pressure tests (LPTs) followed by proof test (PT) and integrated leakage rate test (ILRT) during commissioning. Further the over pressure test (OPT) has been carried out to establish the failure mode of BARCOM Test-Model. The over-pressure test will be completed shortly to reach the functional failure of the test model. Pre-test evaluation of BARCOM was carried out with the results obtained from the registered international round robin participants in January 2009 followed by the post-test assessment in February 2011. The test results along with the various failure modes related to the structural members – concrete, rebars and tendons identified in terms of prescribed milestones are presented in this paper along with the comparison of the pre-test predictions submitted by the registered participants of the Round Robin Analysis for BARCOM test model.

A proposed structural, risk-informed approach to the periodicity of CANDU-6 nuclear containment integrated leak rate testing

Energy Technology Data Exchange (ETDEWEB)

Saliba, N. [McGill Univ., Dept. of Civil Engineering and Applied Mechanics, Montreal, Quebec (Canada); Komljenovic, D. [Hydro-Quebec, Gentilly-2 Nuclear Power Plant, Becancour, Quebec (Canada); Chouinard, L. [McGill Univ., Dept. of Civil Engineering and Applied Mechanics, Montreal, Quebec (Canada); Vaillancourt, R.; Chretien, G. [Hydro-Quebec, Gentilly-2 Nuclear Power Plant, Becancour, Quebec (Canada); Gocevski, V. [Hydro-Quebec Equipements, Montreal, Quebec (Canada)

2010-07-01

As ultimate lines of defense against leakage of large amounts of radioactive material to the environment in case of major reactor accidents, containments have been monitored through well designed periodic tests to ensure their proper performance. Regulatory organizations have imposed types and frequencies of containment tests based on highly-conservative deterministic approaches, and judgments of knowledgeable experts. Recent developments in the perception and methods of risk evaluation have been applied to rationalize the leakage-rate testing frequencies while maintaining risks within acceptable levels, preserving the integrity of containments, and respecting the defense-in-depth philosophy. The objective of this paper is to introduce a proposed risk-informed decision making framework on the periodicity of nuclear containment ILRTs for CANDU-6 nuclear power plants based on five main decision criteria, namely: 1) the containment structural integrity; 2) inputs from PSA Level-2; 3) the requirements of deterministic safety analyses and defense-in-depth concepts; 4- the obligations under regulatory and standard requirements; and 5) the return of experience from nuclear containments historic performance. The concepts of dormant reliability and structural fragility will guide the assessment of the containment structural integrity, within the general context of a global containment life cycle management program. This study is oriented towards the requirements of CANDU-6 reactors, in general, and Hydro-Quebec's Gentilly-2 nuclear power plant, in particular. The present article is the first part in a series of papers that will comprehensively detail the proposed research. (author)

A proposed structural, risk-informed approach to the periodicity of CANDU-6 nuclear containment integrated leak rate testing

International Nuclear Information System (INIS)

Saliba, N.; Komljenovic, D.; Chouinard, L.; Vaillancourt, R.; Chretien, G.; Gocevski, V.

2010-01-01

As ultimate lines of defense against leakage of large amounts of radioactive material to the environment in case of major reactor accidents, containments have been monitored through well designed periodic tests to ensure their proper performance. Regulatory organizations have imposed types and frequencies of containment tests based on highly-conservative deterministic approaches, and judgments of knowledgeable experts. Recent developments in the perception and methods of risk evaluation have been applied to rationalize the leakage-rate testing frequencies while maintaining risks within acceptable levels, preserving the integrity of containments, and respecting the defense-in-depth philosophy. The objective of this paper is to introduce a proposed risk-informed decision making framework on the periodicity of nuclear containment ILRTs for CANDU-6 nuclear power plants based on five main decision criteria, namely: 1) the containment structural integrity; 2) inputs from PSA Level-2; 3) the requirements of deterministic safety analyses and defense-in-depth concepts; 4- the obligations under regulatory and standard requirements; and 5) the return of experience from nuclear containments historic performance. The concepts of dormant reliability and structural fragility will guide the assessment of the containment structural integrity, within the general context of a global containment life cycle management program. This study is oriented towards the requirements of CANDU-6 reactors, in general, and Hydro-Quebec's Gentilly-2 nuclear power plant, in particular. The present article is the first part in a series of papers that will comprehensively detail the proposed research. (author)

Leak rate test of containment personnel lock

International Nuclear Information System (INIS)

Julien, J.T.; Peters, S.W.

1988-01-01

As part of the US NRC Containment Integrity Program, a leak rate test was performed on a full size personnel airlock for a nuclear containment building. The airlock was subjected to conditions simulating severe accident conditions. The objective of the test was to characterize the performance of airlock door seals when subjected to conditions that exceeded design. The seals tested were a double dog-ear configuration and made from EPDM E603. The data obtained from this test will be used by SNL as a benchmark for development of analytical methods. In addition to leak rate information, strain, temperature, displacements, and pressure data were measured and recorded from over 330 transducers. The test lasted approximately 60 hours. Data were recorded at regular intervals and during heating, pressurization and depressurization. The inner airlock door and bulkhead were exposed to a maximum air temperature of 850 F and a maximum air pressure of 300 psig. The airlock was originally designed for 340 F and 60 psig. Two heating and pressurization cycles were planned; one to heat to 400 F and pressurize to 300 psig, and the second to heat to 800 F and pressurize to 300 psig. No significant leakage was recorded during these two cycles. A third cycle was added to the test program. The air temperature was increased to 850 F and held at this temperature for approximately 10 hours. The inner door seal failed quickly at a pressure of 150.5 psig. The maximum leak rate was 706 SCFM

Sodium pool combustion test for small-scale leakage. Run-F7-4 and Run-F8-2

International Nuclear Information System (INIS)

Futagami, Satoshi; Ohno, Shuji

2003-06-01

Since 1998, the test (Run-F7 series) was performed to acquire the fundamental knowledge about the sodium pool growth and floor liner temperature in the case of small-scale leakage of sodium. And the test (Run-F8 series) was performed to know the floor liner material corrosion mechanism under high moisture conditions. In both test series, those influences are investigated by making the rate of sodium leakage, and moisture conditions of supply air into main parameters. As the last test, (1) Run-F7-4 (June 28, 2000) and (2) Run-F8-2 (January 26, 2000) were carried out. The conclusion of the following which receives sodium small-scale leakage (about 10 kg/h) was obtained from these experiments and the result of old Run-F7 and Run-F8 series. The peak temperature of a catch pan tends to become lower with decrease of sodium leak rate. Moreover, height of leak point and moisture conditions also become the factor which raises the catch pan peak temperature. Although it grows up in proportion [almost]to time in early stages of leakage about growth of a sodium pool, growth stops during the leakage. Moreover, the final growth area is mostly proportional to the rate of sodium leakage. It was suggested by the measured value of catch pan corrosion thickness and a material analysis result that the dominant corrosion mechanism was relatively slow Na-Fe double oxidization type corrosion even under the high moisture condition of 4.6 to 4.8%. And the chemical analysis result of a deposits also suggested that the catch pan material was in the environment in which molten salt type corrosion was not easy to occur. (author)

Radiofrequency radiation leakage from microwave ovens

International Nuclear Information System (INIS)

Lahham, A.; Sharabati, A.

2013-01-01

This work presents data on the amount of radiation leakage from 117 microwave ovens in domestic and restaurant use in the West Bank, Palestine. The study of leakage is based on the measurements of radiation emissions from the oven in real-life conditions by using a frequency selective field strength measuring system. The power density from individual ovens was measured at a distance of 1 m and at the height of centre of door screen. The tested ovens were of different types, models with operating powers between 1000 and 1600 W and ages ranging from 1 month to >20 y, including 16 ovens with unknown ages. The amount of radiation leakage at a distance of 1 m was found to vary from 0.43 to 16.4 μW cm -1 with an average value equalling 3.64 μW cm -2 . Leakages from all tested microwave ovens except for seven ovens (∼6 % of the total) were below 10 μW cm -2 . The highest radiation leakage from any tested oven was ∼16.4 μW cm -2 , and found in two cases only. In no case did the leakage exceed the limit of 1 μWcm -1 recommended by the ICNIRP for 2.45-GHz radiofrequency. This study confirms a linear correlation between the amount of leakage and both oven age and operating power, with a stronger dependence of leakage on age. (authors)

Microbial leakage of MTA, Portland cement, Sealapex and zinc oxide-eugenol as root-end filling materials.

Science.gov (United States)

Estrela, Carlos; Estrada-Bernabé, Pedro-Felício; de Almeida-Decurcio, Daniel; Almeida-Silva, Julio; Rodrigues-Araújo-Estrela, Cyntia; Poli-Figueiredo, José-Antonio

2011-05-01

The aim of this study was to compare the microbial leakage of mineral trioxide aggregate (MTA), Portland cement (PC), Sealapex and zinc oxide-eugenol (ZOE) as root-end filling materials. An in vitro microbial leakage test (MLT) with a split chamber was used in this study. A mixture of facultative bacteria and one yeast (S. aureus+E. faecalis+P. aeruginosa+B. subtilis+C. albicans) was placed in the upper chamber and it could only reach the lower chamber containing Brain Heart Infusion broth by way of leakage through the root-end filling. Microbial leakage was observed daily for 60 days. Sixty maxillary anterior human teeth were randomly assigned to different groups--MTA and PC (gray and white), Sealapex+zinc oxide and ZOE, control groups and subgroups to evaluate the influence of EDTA for smear layer removal. These materials were further evaluated by an agar diffusion test (ADT) to verify their antimicrobial efficacy. Data were analyzed statistically by Kruskal-Wallis and Mann-Whitney test. In the MLT, Sealapex+zinc oxide and ZOE did not show evidence of microbial leakage over the 60-day experimental period. The other materials showed leakage from the 15th day. The presence of smear layer influenced microbial leakage. Microbial inhibition zones were not observed in all samples tested by ADT. Sealapex+zinc oxide and ZOE did not show microbial leakage over the experimental period, whereas it was verified within 15 to 45 days in MTA and Portland cement.

Inward contaminant leakage tests of the S-Tron Corporation emergency escape breathing device.

Science.gov (United States)

1992-04-01

At the request of S-Tron Corporation, to support their contract with the U.S. Navy, performance tests of the Emergency Escape Breathing Device (EEBD) were conducted in the Environmental Physiology Research Section contaminant leakage chamber. Sulfur ...

Containment long-term operational integrity

International Nuclear Information System (INIS)

Sammataro, R.F.

1990-01-01

Periodic integrated leak rate tests are required to assure that containments continue to meet allowable leakage limits. Although overall performance has been quite good to date, several major containment aging and degradation mechanisms have been identified. Two pilot plant life extension (PLEX) studies serve as models for extending the operational integrity of present containments for light-water cooled nuclear power plants in the United States. One study is for a Boiling-Water Reactor (BWR) and the second is for a Pressurized-Water Reactor (PWR). Research and testing programs for determining the ultimate pressure capacity and failure mechanisms for containments under severe loading conditions and studies for extending the life of current plants beyond the present 40-year licensed lifetime are under way. This paper presents an overview of containment designs in the United States. Also presented are a discussion of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) and regulatory authority requirements for the design, construction, inservice inspection, leakage testing and repair of steel and concrete containments. Findings for containments from the pilot PLEX studies and continuing containment integrity research and testing programs are discussed. The ASME Code and regulatory requirements together with recommendations from the PLEX studies and containment integrity research and testing provide a basis for continued containment long-term operational integrity. (orig./GL)

Concrete containment integrity program at EPRI

International Nuclear Information System (INIS)

Winkleblack, R.K.; Tang, Y.K.

1984-01-01

Many in the nuclear power plant business believe that the catastrophic failure mode for reactor containment structures is unrealistic. One of the goals of the EPRI containment integrity program is to demonstrate that this is true. The objective of the program is to provide the utility industry with an experimental data base and a test-validated analytical method for realistically evaluating the actual over-pressure capability of concrete containment buildings and to predict leakage behavior if higher pressures were to occur. The ultimate goal of this research effort is to characterize the containment leakage mode and rate as a function of internal pressure and time so that the risk can be realistically assessed for hypothetical degraded core accidents. Progress in the first and second phases of the three-phase analytical and testing efforts is discussed

CTP (Cochlin-tomoprotein) detection in the profuse fluid leakage (gusher) from cochleostomy.

Science.gov (United States)

Ikezono, Tetsuo; Sugizaki, Kazuki; Shindo, Susumu; Sekiguchi, Satomi; Pawankar, Ruby; Baba, Shunkichi; Yagi, Toshiaki

2010-08-01

By testing 125 samples, we confirmed that Cochlin-tomoprotein (CTP) is present in the perilymph, not in cerebrospinal fluid (CSF). Perilymph and CSF exist in two distinct compartments, even in the case of a malformed inner ear with a bony defect in the lamina cribrosa, as described here. Cochleostomy might have suddenly decreased the perilymph pressure, allowing the influx of CSF into the inner ear resulting in profuse fluid leakage, first perilymph then CSF. The first purpose of this study was to further confirm the specificity of the perilymph-specific protein CTP that we reported recently. Secondly, we assessed the nature of the fluid leakage from the cochleostomy using the CTP detection test. A standardized CTP detection test was performed on 65 perilymph and 60 CSF samples. Samples of profuse fluid leakage collected from cochleostomy during cochlear implantation surgery of one patient with branchio-oto-renal (BOR) syndrome were also tested by the CTP detection test. CTP was detected in 60 of 65 perilymph samples but not in any of the CSF samples. The leaked fluid was shown to contain CTP, i.e. perilymph, at the outset, and then the CTP detection signals gradually disappeared as time elapsed.

Thermal-hydraulic analysis for changing feedwater check valve leakage rate testing methodology

International Nuclear Information System (INIS)

Fuller, R.; Harrell, J.

1996-01-01

The current design and testing requirements for the feedwater check valves (FWCVs) at the Grand Gulf Nuclear Station are established from original licensing requirements that necessitate extremely restrictive air testing with tight allowable leakage limits. As a direct result of these requirements, the original high endurance hard seats in the FWCVs were modified with elastomeric seals to provide a sealing surface capable of meeting the stringent air leakage limits. However, due to the relatively short functional life of the elastomeric seals compared to the hard seats, the overall reliability of the sealing function actually decreased. This degraded performance was exhibited by frequent seal failures and subsequent valve repairs. The original requirements were based on limited analysis and the belief that all of the high energy feedwater vaporized during the LOCA blowdown. These phenomena would have resulted in completely voided feedwater lines and thus a steam environment within the feedwater leak pathway. To challenge these criteria, a comprehensive design basis accident analysis was developed using the RELAP5/MOD3.1 thermal-hydraulic code. Realistic assumptions were used to more accurately model the post-accident fluid conditions within the feedwater system. The results of this analysis demonstrated that no leak path exists through the feedwater lines during the reactor blowdown phase and that sufficient subcooled water remains in various portions of the feedwater piping to form liquid water loop seals that effectively isolate this leak path. These results provided the bases for changing the leak testing requirements of the FWCVs from air to water. The analysis results also established more accurate allowable leakage limits, determined the real effective margins associated with the FWCV safety functions, and led to design changes that improved the overall functional performance of the valves

Thermal-hydraulic analysis for changing feedwater check valve leakage rate testing methodology

Energy Technology Data Exchange (ETDEWEB)

Fuller, R.; Harrell, J.

1996-12-01

The current design and testing requirements for the feedwater check valves (FWCVs) at the Grand Gulf Nuclear Station are established from original licensing requirements that necessitate extremely restrictive air testing with tight allowable leakage limits. As a direct result of these requirements, the original high endurance hard seats in the FWCVs were modified with elastomeric seals to provide a sealing surface capable of meeting the stringent air leakage limits. However, due to the relatively short functional life of the elastomeric seals compared to the hard seats, the overall reliability of the sealing function actually decreased. This degraded performance was exhibited by frequent seal failures and subsequent valve repairs. The original requirements were based on limited analysis and the belief that all of the high energy feedwater vaporized during the LOCA blowdown. These phenomena would have resulted in completely voided feedwater lines and thus a steam environment within the feedwater leak pathway. To challenge these criteria, a comprehensive design basis accident analysis was developed using the RELAP5/MOD3.1 thermal-hydraulic code. Realistic assumptions were used to more accurately model the post-accident fluid conditions within the feedwater system. The results of this analysis demonstrated that no leak path exists through the feedwater lines during the reactor blowdown phase and that sufficient subcooled water remains in various portions of the feedwater piping to form liquid water loop seals that effectively isolate this leak path. These results provided the bases for changing the leak testing requirements of the FWCVs from air to water. The analysis results also established more accurate allowable leakage limits, determined the real effective margins associated with the FWCV safety functions, and led to design changes that improved the overall functional performance of the valves.

The Effect of Internal Leakages on Thermal Performance in NPPs

International Nuclear Information System (INIS)

Heo, Gyun Young; Kim, Doo Won; Jang, Seok Bo

2007-01-01

Since the Balance Of Plant (BOP, limited to a turbine cycle in this study) does not contain radioactive material, regulatory authorities did not need to have concerns on it. As the interests on safety and performance is getting more serious and extensive, controlling the level of safety and performance of a BOP have just begun or is about to begin. The performance standards or ageing management programs of the major equipment in a BOP is being developed. The regulatory requirements for tests and/or maintenance are being actively built up. There is also a probabilistic approach quantifying performance of a BOP. The study on quantifying the rate of unanticipated shutdowns caused by careless maintenance and/or tests conducted in a BOP is going on. In this study, the modeling of the entire BOP and the methodologies of thermal performance analysis should be one of the must-have items as well. This study was achieved to ensure fundamental skills related to 1) the detailed steady-state modeling of a BOP and 2) thermal performance analysis under various conditions. Particularly, the paper will focus on the effect of internal leakages inside the valves and FeedWater Heaters (FWHs). The internal leakage is regarded as the flow movement through the isolated path but remaining inside the system boundary of a BOP. For instance, the leakage from one side of a valve seat to the other side, or the leakage through the cracked tubes or tube-sheets in a heat exchanger correspond to internal leakages. We made a BOP model of OPR1000 and investigated thermal performance under the internal leakage in Turbine Bypass Condenser Dump Valves (TBCDV) and FWHs

Abutment Coating With Diamond-Like Carbon Films to Reduce Implant-Abutment Bacterial Leakage.

Science.gov (United States)

Cardoso, Mayra; Sangalli, Jorgiana; Koga-Ito, Cristiane Yumi; Ferreira, Leandro Lameirão; da Silva Sobrinho, Argemiro Soares; Nogueira, Lafayette

2016-02-01

The influence of diamond-like carbon (DLC) films on bacterial leakage through the interface between abutments and dental implants of external hexagon (EH) and internal hexagon (IH) designs was evaluated. Film deposition was performed by plasma-enhanced chemical vapor deposition. Sets of implants and abutments (n = 30 per group, sets of 180 implants) were divided according to connection design and treatment of the abutment base: 1) no treatment (control); 2) DLC film deposition; and 3) Ag-DLC film deposition. Under sterile conditions, 1 μL Enterococcus faecalis was inoculated inside the implants, and abutments were tightened. The sets were tested for immediate external contamination, suspended in test tubes containing sterile culture broth, and followed for 5 days. Turbidity of the broth indicated bacterial leakage. At the end of the period, the abutments were removed and the internal content of the implants was collected with paper points and plated in Petri dishes. After 24-hour incubation, they were assessed for bacterial viability and colony-forming unit counting. Bacterial leakage was analyzed by χ(2) and Fisher exact tests (α = 5%). The percentage of bacterial leakage was 16.09% for EH implants and 80.71% for IH implants (P DLC and Ag-DLC films do not significantly reduce the frequency of bacterial leakage and bacteria load inside the implants.

Air-steam leakage through cracks in concrete

International Nuclear Information System (INIS)

Georges Nahas; Helene Simon

2005-01-01

Full text of publication follows: In the context of a severe accident in a Pressurised Water nuclear plant, the evaluation of the leakage rate through the containment wall remains a key point of the safety analysis, because it influences directly the consequences on the environment. During a severe accident, large amounts of steam could be released in the containment; internal pressure could rise beyond design limits causing cracks to appear in the internal concrete wall of the double-wall containment and fission products to leak towards the containment annulus. A research program led by the French Institute for Radiological Protection and Nuclear Safety aims to estimate this leakage. In the presence of cracks, most of the leak flows through them. Hence, a first phase of the program was to build a two-phase homogeneous model for the flow of an air-steam mixture through a idealized traversing crack, taking into account condensation phenomena, and considering crack openings from 25 μm to several hundred μm. A numerical model for the flow, coupled with heat transfer in the wall, was implemented in the Finite Element code CAST3M. This model was validated on a small scaled experiment which was made of two parallel glass plates. Comparison of the numerical and experimental results in this 'channel case' has shown good results for the total mass flow rate for channel openings greater than 100 μm. For the 50 μm opening the calculation gave a 50 % estimate of the experimental total mass flow rate. The second phase of the program is now to validate the model on cracks performed in a concrete specimen. In order to do so, we have simulated the experiment VK2/2 described in the article named 'Investigation of the leakage behavior of reinforced concrete walls' by N. Herrmann, C. Niklasch, M. Stegemann, L. Stempniewski. The reinforced concrete slab, 2.7 m long in the reinforcement direction and 1.2 m thick in the cracking direction, is placed in a mechanical set-up and an

Leakage localisation method in a water distribution system based on sensitivity matrix: methodology and real test

OpenAIRE

Pascual Pañach, Josep

2010-01-01

Leaks are present in all water distribution systems. In this paper a method for leakage detection and localisation is presented. It uses pressure measurements and simulation models. Leakage localisation methodology is based on pressure sensitivity matrix. Sensitivity is normalised and binarised using a common threshold for all nodes, so a signatures matrix is obtained. A pressure sensor optimal distribution methodology is developed too, but it is not used in the real test. To validate this...

Reactor coolant pressure boundary leakage detection system

International Nuclear Information System (INIS)

Dissing, E.; Svansson, L.

1980-01-01

This study deals with a system for monitoring the leakage of reactor coolant. This system is based primarily on the detection of the 13 N content in the containment atmosphere. 13 N is produced from the oxygen of the reactor water via the recoil proton nuclear process Hl+016/yields/ 13 N+ 4 He. The generation is therefore independent of fuel element leakage and of the corrosion product content in the water. It is solely related to the neutron flux level in the reactor core. Typical figures for the equilibrium 13 N concentration in the containment atmosphere following a 4 kg/minute coolant leakage are 5 kBq m/sup -3/ and 7 kBq m/sup -3/ for BWR and PWR respectively. These levels are readily measured with a 10 liter Ge(Li) flow detector assembly operated at elevated pressure. 8 refs

Reactor coolant pressure boundary leakage detection system

International Nuclear Information System (INIS)

Dissing, E.; Svansson, L.

1980-01-01

This study deals with a system for monitoring the leakage of reactor coolant. This system is based primarily on the detection of the N13 content in the containment atmosphere. N13 is produced from the oxygen of the reactor water via the recoil proton nuclear process Hl+016/yields/Nl3+He4. The generation is therefore independent of fuel element leakage and of the corrosion product content in the water. It is solely related to the neutron flux level in the reactor core. Typical figures for the equilibrium N13 concentration in the containment atmosphere following a 4 kg/minute coolant leakage are 5 kBq m/sup -3/ and 7 kBq m/sup -3/ for BWR and PWR respectively. These levels are readily measured with a 10 liter Ge(Li) flow detector assembly operated at elevated pressure. 8 refs

Reactor coolant pressure boundary leakage detection system

International Nuclear Information System (INIS)

Dissing, E.; Svansson, L.

1979-08-01

The present paper deals with a system for monitoring the leakage of reactor coolant. This system is based primarily on the detection of the N13 content in the containment atmosphere. N13 is produced from the oxygen of the reactor water via the recoil proton nuclear process H1+016 → N13+He4. The generation is therefore independent of fuel element leakage and of the corrosion product content in the water. It is solely related to the neutron flux level in the reactor core. Typical figures for the equilibrium N13 concentration in the containment atmosphere following a 4 kg/minute coolant leakage are 5 kBq m -3 and 7 kBq m -3 for BWR and PWR respectively. These levels are readily measured with a 10 liter Ge (Li) flow detector assembly operated at elevated pressure. (Auth.)

Performance tests of the reactor containment structures of HTTR

International Nuclear Information System (INIS)

Sakaba, Nariaki; Iigaki, Kazuhiko; Kawaji, Satoshi; Iyoku, Tatsuo

1998-03-01

The containment structures of the HTTR consist of the reactor containment vessel (CV), service area (SA) and emergency air purification system, which minimize the release of FPs in the postulated accidents with FP release from the reactor facilities. The CV is designed to withstand the temperature and pressure transients and to be leak-tight within the specified leakage limit even in the case of a rupture of the primary concentric hot gas duct. The pressure of inside of the SA should be maintained slightly lower than that of atmosphere by the emergency air purification system. The radioactive materials are released from the stack to environment via the emergency air purification system under the accident condition. Then the emergency air purification system should remove airborne radio-activities and should maintain proper pressure in the SA. We established the method to measure leak rate of the CV with closed reactor coolant pressure boundary although it is normally measured under opened reactor coolant pressure boundary as employed in LWRs. The CV leak rate test was carried out by the newly developed method and the expected performance was obtained. The SA and emergency air purification system were also confirmed by the performance test. We concluded that the reactor containment structures were fabricated to minimize the release of FPs in the postulated accidents with FP release from the reactor facilities. (author)

Benchmark calculations for evaluation methods of gas volumetric leakage rate

International Nuclear Information System (INIS)

Asano, R.; Aritomi, M.; Matsuzaki, M.

1998-01-01

A containment function of radioactive materials transport casks is essential for safe transportation to prevent the radioactive materials from being released into environment. Regulations such as IAEA standard determined the limit of radioactivity to be released. Since is not practical for the leakage tests to measure directly the radioactivity release from a package, as gas volumetric leakages rates are proposed in ANSI N14.5 and ISO standards. In our previous works, gas volumetric leakage rates for several kinds of gas from various leaks were measured and two evaluation methods, 'a simple evaluation method' and 'a strict evaluation method', were proposed based on the results. The simple evaluation method considers the friction loss of laminar flow with expansion effect. The strict evaluating method considers an exit loss in addition to the friction loss. In this study, four worked examples were completed for on assumed large spent fuel transport cask (Type B Package) with wet or dry capacity and at three transport conditions; normal transport with intact fuels or failed fuels, and an accident in transport. The standard leakage rates and criteria for two kinds of leak test were calculated for each example by each evaluation method. The following observations are made based upon the calculations and evaluations: the choked flow model of ANSI method greatly overestimates the criteria for tests ; the laminar flow models of both ANSI and ISO methods slightly overestimate the criteria for tests; the above two results are within the design margin for ordinary transport condition and all methods are useful for the evaluation; for severe condition such as failed fuel transportation, it should pay attention to apply a choked flow model of ANSI method. (authors)

Hypothetical accident conditions, free drop and thermal tests: Specification 6M

International Nuclear Information System (INIS)

Blankenship, R.W.

1980-05-01

The 30 gallon Specification 6M shipping container with rolled-top food pack cans as inner containers is evaluated under conditions required by 10 CFR 71.42. One kilogram of depleted uranium as UO 2 was packaged in each of the inner containers. After completion of a free drop test and a simulated thermal test, the maximum observed leakage of UO 2 for the following week was 3.2 μg. This leakage is well below the allowable leakage per week for most plutonium isotopic mixtures. Using the examples provided, any plutonium isotopic mixture can be easily compared with the allowable leakage per week. Test conditions and results are reported

Mass extraction container closure integrity physical testing method development for parenteral container closure systems.

Science.gov (United States)

Yoon, Seung-Yil; Sagi, Hemi; Goldhammer, Craig; Li, Lei

2012-01-01

Container closure integrity (CCI) is a critical factor to ensure that product sterility is maintained over its entire shelf life. Assuring the CCI during container closure (C/C) system qualification, routine manufacturing and stability is important. FDA guidance also encourages industry to develop a CCI physical testing method in lieu of sterility testing in a stability program. A mass extraction system has been developed to check CCI for a variety of container closure systems such as vials, syringes, and cartridges. Various types of defects (e.g., glass micropipette, laser drill, wire) were created and used to demonstrate a detection limit. Leakage, detected as mass flow in this study, changes as a function of defect length and diameter. Therefore, the morphology of defects has been examined in detail with fluid theories. This study demonstrated that a mass extraction system was able to distinguish between intact samples and samples with 2 μm defects reliably when the defect was exposed to air, water, placebo, or drug product (3 mg/mL concentration) solution. Also, it has been verified that the method was robust, and capable of determining the acceptance limit using 3σ for syringes and 6σ for vials. Sterile products must maintain their sterility over their entire shelf life. Container closure systems such as those found in syringes and vials provide a seal between rubber and glass containers. This seal must be ensured to maintain product sterility. A mass extraction system has been developed to check container closure integrity for a variety of container closure systems such as vials, syringes, and cartridges. In order to demonstrate the method's capability, various types of defects (e.g., glass micropipette, laser drill, wire) were created in syringes and vials and were tested. This study demonstrated that a mass extraction system was able to distinguish between intact samples and samples with 2 μm defects reliably when the defect was exposed to air, water

Probabilistic finite element investigation of prestressing loss in nuclear containment wall segments

International Nuclear Information System (INIS)

Balomenos, Georgios P.; Pandey, Mahesh D.

2017-01-01

Highlights: • Probabilistic finite element framework for assessing concrete strain distribution. • Investigation of prestressing loss based on concrete strain distribution. • Application to 3D nuclear containment wall segments. • Use of ABAQUS with python programing for Monte Carlo simulation. - Abstract: The main function of the concrete containment structures is to prevent radioactive leakage to the environment in case of a loss of coolant accident (LOCA). The Canadian Standard CSA N287.6 (2011) proposes periodic inspections, i.e., pressure testing, in order to assess the strength and design criteria of the containment (proof test) and the leak tightness of the containment boundary (leakage rate test). During these tests, the concrete strains are measured and are expected to have a distribution due to several uncertainties. Therefore, this study aims to propose a probabilistic finite element analysis framework. Then, investigates the relationship between the concrete strains and the prestressing loss, in order to examine the possibility of estimating the average prestressing loss during pressure testing inspections. The results indicate that the concrete strain measurements during the leakage rate test may provide information with respect to the prestressing loss of the bonded system. In addition, the demonstrated framework can be further used for the probabilistic finite element analysis of real scale containments.

Probabilistic finite element investigation of prestressing loss in nuclear containment wall segments

Energy Technology Data Exchange (ETDEWEB)

Balomenos, Georgios P., E-mail: gbalomen@uwaterloo.ca; Pandey, Mahesh D., E-mail: mdpandey@uwaterloo.ca

2017-01-15

Highlights: • Probabilistic finite element framework for assessing concrete strain distribution. • Investigation of prestressing loss based on concrete strain distribution. • Application to 3D nuclear containment wall segments. • Use of ABAQUS with python programing for Monte Carlo simulation. - Abstract: The main function of the concrete containment structures is to prevent radioactive leakage to the environment in case of a loss of coolant accident (LOCA). The Canadian Standard CSA N287.6 (2011) proposes periodic inspections, i.e., pressure testing, in order to assess the strength and design criteria of the containment (proof test) and the leak tightness of the containment boundary (leakage rate test). During these tests, the concrete strains are measured and are expected to have a distribution due to several uncertainties. Therefore, this study aims to propose a probabilistic finite element analysis framework. Then, investigates the relationship between the concrete strains and the prestressing loss, in order to examine the possibility of estimating the average prestressing loss during pressure testing inspections. The results indicate that the concrete strain measurements during the leakage rate test may provide information with respect to the prestressing loss of the bonded system. In addition, the demonstrated framework can be further used for the probabilistic finite element analysis of real scale containments.

Leakage characterization of a piloted power operated relief valve

International Nuclear Information System (INIS)

Ezekoye, L.I.; Hess, M.D.

1995-01-01

In Westinghouse Pressurized Water Reactors (PWRs), power operated relief valves (PORVs) are used to provide overpressure protection of the Pressurizer. The valves are fail closed globe valves which means that power is required to open the valves and, on loss of power, the valves close. There are two ways to operate the PORVs. The more common way is to directly couple the disc to an actuator via a disc-stem assembly. The type of design is not the object of this paper. The other and less common way of operating a PORV is by piloting the main valve such that the opening or closing of a pilot valve opens and closes the main valve. This is the design of interest. In most plants, the PORVs are installed with a water loop seal while in some plants no water loop seals are used. It is generally accepted that loop seal installation minimizes valve seat leakage. In non-loop seal installation, the valve seat is exposed to steam which increases the potential for seat leakage. This paper describes the results of some tests performed with nitrogen and steam to characterize the leakage potential of a pilot operated PORV. The test results were compared with seat leakage tests of check valves to provide insight on the leakage testing of pilot operated valves and check valves. The paper also compares the test data with leakage estimates using the ASME/ANSI OM Code guidance on valve leakage

Hypothetical accident conditions free drop and thermal tests USA/5791/BLF (ERDA-AL)

International Nuclear Information System (INIS)

Blankenship, R.W.

1980-05-01

The USA/5791/BLF (ERDA-AL) shipping container with rolled-top food pack cans as inner containers is evaluated under conditions required by 10 CFR 71.42. One kilogram of depleted uranium as UO 2 was packaged in each of the inner containers. After completion of a free drop test and a simulated thermal test, the maximum observed leakage of UO 2 for the following week was 3.0 μg. This leakage is well below the allowable leakage per week for most plutonium isotopic mixtures. Using the examples provided, any plutonium isotopic mixture can be easily compared with the allowable leakage per week. Test conditions and results are reported

A Lift-Off-Tolerant Magnetic Flux Leakage Testing Method for Drill Pipes at Wellhead

OpenAIRE

Wu, Jianbo; Fang, Hui; Li, Long; Wang, Jie; Huang, Xiaoming; Kang, Yihua; Sun, Yanhua; Tang, Chaoqing

2017-01-01

To meet the great needs for MFL (magnetic flux leakage) inspection of drill pipes at wellheads, a lift-off-tolerant MFL testing method is proposed and investigated in this paper. Firstly, a Helmholtz coil magnetization method and the whole MFL testing scheme are proposed. Then, based on the magnetic field focusing effect of ferrite cores, a lift-off-tolerant MFL sensor is developed and tested. It shows high sensitivity at a lift-off distance of 5.0 mm. Further, the follow-up high repeatabilit...

Decision Analysis and Its Application to the Frequency of Containment Integrated Leakage Rate Tests

International Nuclear Information System (INIS)

Apostolakis, George E.; Koser, John P.; Sato, Gaku

2004-01-01

For nuclear utilities to become competitive in a deregulated electricity market, costs must be reduced, safety must be maintained, and interested stakeholders must remain content with the decisions being made. One way to reduce costs is to reduce the frequency of preventive maintenance and testing. However, these changes must be weighed against their impact on safety and stakeholder relations. We present a methodology that allows the evaluation of decision options using a number of objectives that include safety, economics, and stakeholder relations. First, the candidate decision options are screened to make sure that they satisfy the relevant regulatory requirements. The remaining options are evaluated using multiattribute utility theory. The results of the formal analysis include a ranking of the options according to their desirability as well as the major reasons that explain this ranking. These results are submitted to a deliberative process in which the decision makers scrutinize the results to ensure that they are meaningful. During the deliberation, new decision options may be formulated based on the insights that the formal analysis provides, as happened in the case study of this paper. This case study deals with the reduction in frequency of the containment integrated leak rate test of a boiling water reactor

Maintaining leak tightness capability of Caorso BWR containment

International Nuclear Information System (INIS)

Barsanti, P.; Di Palo, L.; Grimaldi, G.

1988-01-01

In 1987 the local leak rate test (LLRT) results of the primary containment were revised, with the following main goals: to highlight recurring problems, leading to lack of leak tightness of the primary containment; to individuate the pertinent degradation mechanisms; to assess the corrective actions already implemented and to plan further improvements, if necessary; and to optimize the preventive maintenance program on the containment, particularly the inspection frequency. All LLRTs in the past operating period, both before (as found) and after (as left) maintenance were analyzed, in terms of leakage rate and equivalent area of leak, for each penetration. Corrective actions already implemented included replacement of some valves with better quality type one, passivation of the carbon steel pipes and improvement of the pertinent surveillance procedures. Long term corrective actions, now under consideration, will include the following: more extensive passivation of pipes, carrying humid air, so that oxidation could be drastically reduced; better chemistry control in fluid systems; extensive replacement of the butterfly valves presently used; implementation of the LLRT practice, such to quantitatively measure the leakage rate, also in presence of large leak; and reduction of the time interval between periodical tests, on the basis of the results of the previous ones. Following these guidelines, future overall leakage tests would be performed in as found condition, aimed to verify the effectiveness of the entire maintenance and testing program of the primary containment and of its capability to maintain leak tightness during the time between two subsequent tests

Behaviour of prestressed concrete containment structures

International Nuclear Information System (INIS)

MacGregor, J.G.; Murray, D.W.; Simmonds, S.H.

1980-05-01

The most significant finds from a study to assess the response of prestressed concrete secondary containment structures for nuclear reactors under the influence of high internal overpressures are presented. A method of analysis is described for determining the strains and deflections including effects of inelastic behaviour at various points in the structure resulting from increasing internal pressures. Experimentally derived relationships between the strains and crack spacing, crack width and leakage rate are given. These procedures were applied to the Gentilly-2 containment building to obtain the following results: (1) The first through-the-wall cracks would occur in the dome at 48 psi or 2.3 times the proof test pressure. (2) At this pressure leakage would begin and would increase exponentially as the pressure increases such that at 93% of the predicted failure load the calculated leakage rate would be approximately equal to the volume of the containment each second. (3) Assuming the pressurizing medium could be supplied sufficiently rapidly, failure would occur due to rupture of the horizontal tendons at approximately 77 psi. (author)

PERFORMANCE OF LEAKAGE POWER MINIMIZATION TECHNIQUE FOR CMOS VLSI TECHNOLOGY

Directory of Open Access Journals (Sweden)

T. Tharaneeswaran

2012-06-01

Full Text Available Leakage power of CMOS VLSI Technology is a great concern. To reduce leakage power in CMOS circuits, a Leakage Power Minimiza-tion Technique (LPMT is implemented in this paper. Leakage cur-rents are monitored and compared. The Comparator kicks the charge pump to give body voltage (Vbody. Simulations of these circuits are done using TSMC 0.35µm technology with various operating temper-atures. Current steering Digital-to-Analog Converter (CSDAC is used as test core to validate the idea. The Test core (eg.8-bit CSDAC had power consumption of 347.63 mW. LPMT circuit alone consumes power of 6.3405 mW. This technique results in reduction of leakage power of 8-bit CSDAC by 5.51mW and increases the reliability of test core. Mentor Graphics ELDO and EZ-wave are used for simulations.

Leak monitoring method for a reactor container

International Nuclear Information System (INIS)

Uehara, Toshio.

1987-01-01

Purpose: To confirm leakages from a container upon nuclear reactor operation. Method: Leakages from a nuclear reactor container has been prevented by lowering the inner pressure of the container relative to the external pressure. In the conventional method of calculating the leakage by applying an inner pressure to the container and measuring the pressure change, etc. after the elapse of a pre-determined time, the measurement has to be conducted at periodical inspection when the nuclear reactor is shut-down. In view of the above, the leak test is conducted in the present invention by applying a slight inner pressure to the inside of the reactor container by supplying gases from a gas supply system and detecting the flow rate of the gases in the gas supply system while maintaining the slight inner pressure constant by controlling the supply and discharge of the gases. By applying such a inner pressure as causing no effect to the reactor operation, it is possible to monitor the leaks during operation and to detect the flow rate value surely and continuously if the leak is resulted. (Kamimura, M.)

On Probability Leakage

OpenAIRE

Briggs, William M.

2012-01-01

The probability leakage of model M with respect to evidence E is defined. Probability leakage is a kind of model error. It occurs when M implies that events $y$, which are impossible given E, have positive probability. Leakage does not imply model falsification. Models with probability leakage cannot be calibrated empirically. Regression models, which are ubiquitous in statistical practice, often evince probability leakage.

Radioactive particulate release associated with the DOT specification 6M container under hypothetical accident conditions

International Nuclear Information System (INIS)

Taylor, J.M.; Raney, P.J.

1986-02-01

A testing program was conducted to determine the leakage of depleted uranium dioxide powder (DUO) from the inner containment components of the US Department of Transportation's (DOT) specification 6M container under hypothetical accident conditions. Depleted uranium dioxide was selected as a surrogate for plutonium oxide because of the similarities in the powder characteristics, density and particle size, and because of the special handling and special facilities required for plutonium oxide. The DUO was packaged inside food pack cans in three different configurations inside the 2R vessel of the 6M container. The amount of DUO powder leakage ranged from none detectable ( -7 g) to a high of 1 x 10 -3 g. The combination of gravity, vibration and pressure produced the highest leakage of DUO. Containers that had hermetic seals (leak rates -4 atm cc/min) did not leak any detectable amount ( -7 g) of DUO under the test conditions. Impact forces had no effect on the leakage of particles with the packaging configurations used. 23 refs., 24 figs., 3 tabs

Component external leakage and rupture frequency estimates

International Nuclear Information System (INIS)

Eide, S.A.; Khericha, S.T.; Calley, M.B.; Johnson, D.A.; Marteeny, M.L.

1991-11-01

In order to perform detailed internal flooding risk analyses of nuclear power plants, external leakage and rupture frequencies are needed for various types of components - piping, valves, pumps, flanges, and others. However, there appears to be no up-to-date, comprehensive source for such frequency estimates. This report attempts to fill that void. Based on a comprehensive search of Licensee Event Reports (LERs) contained in Nuclear Power Experience (NPE), and estimates of component populations and exposure times, component external leakage and rupture frequencies were generated. The remainder of this report covers the specifies of the NPE search for external leakage and rupture events, analysis of the data, a comparison with frequency estimates from other sources, and a discussion of the results

Gross Containment Leakage Monitoring System (GCLM) applied to accidental impairment of containment integrity determination

International Nuclear Information System (INIS)

Dinu, Camelia; Talpalariu, A.; Constantinescu, G.

2007-01-01

The Prioritization of Generic Safety Issues (NUREG-0933 of October 2006), section 1 task II.E.4 item II.E.4.3 recommends that a method of periodic or continuous testing has to be available, in order to detect unknown gross openings in the nuclear power plants containment structure. The Palisades incident and three other incidents are exemplified, when the reactor was operated for about 1.5 years, while the containment isolation valves in a purge system bypass line were unknowingly locked in the open position. It was estimated that the presence of a GCLM system could identify an unknown breach and reduce the expected unavailability of containment due to containment integrity breach events, to a 1.6x10 -3 /year demand. (authors)

Signal attenuation due to cavity leakage

International Nuclear Information System (INIS)

Sherman, M.H.; Modera, M.P.

1988-01-01

The propagation of sound waves in fluids requires information about three properties of the system: capacitance (compressibility), resistance (friction), and inductance (inertia). Acoustical design techniques to date have tended to ignore the frictional effects associated with airflow across the envelope of the acoustic cavity (e.g., resistive vents). Since such leakage through the cavity envelope is best expressed with a power law dependence on the pressure, standard Fourier techniques that rely on linearity cannot be used. In this article, the theory relevant to nonlinear leakage is developed and equations presented. Potential applications of the theory to techniques for quantifying the leakage of buildings are presented. Experimental results from pressure decays in a full-scale test structure are presented and the leakage so measured is compared with independent measurements to demonstrate the technique

Containment long-term operational integrity--a 1988 status report

International Nuclear Information System (INIS)

Sammataro, R.F.

1988-01-01

Design and in-service codes and standards provide a comprehensive set of requirements for containment design, construction, inspection, testing and repair. Metal and concrete containments must be designed, fabricated, constructed, inspected, tested and maintained to quality standards commensurate with the importance of the safety function to be performed. Periodic integrated leak rate tests are required to assure that containments continue to meet allowable leakage limits. Although overall performance has been quite good to date, several major containment aging and degradation mechanisms have been identified. Two pilot plant life extension studies, one for a boiling water reactor and one for a pressurized water reactor, serve as models for extending the operational integrity of present containments in the United States. Research and testing programs for determining the ultimate pressure capacity and failure mechanisms for containments under severe loading conditions and studied for extending the life of current plants beyond the present 40 year licensed lifetime are underway. This paper presents an overview of containment designs in the USA and a discussion of the regulatory and ASME Code requirements for the design, construction, in-service inspection, testing and repair for containments. Findings for containments from the pilot plant life extension studies and the ongoing containment research and testing programs are also discussed. The regulatory and ASME Code requirements for design, construction, in-service inspection and periodic integrated leakage testing together with recommendations from the plant life extension studies and containment integrity research and testing provide a basis for continued containment long-term operational integrity

Pre-test analysis of ATLAS SBO with RCP seal leakage scenario using MARS code

Energy Technology Data Exchange (ETDEWEB)

Pham, Quang Huy; Lee, Sang Young; Oh, Seung Jong [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

2015-10-15

This study presents a pre-test calculation for the Advanced Thermal-hydraulic Test Loop for Accident Simulation (ATLAS) SBO experiment with RCP seal leakage scenario. Initially, turbine-driven auxfeed water pumps are used. Then, outside cooling water injection method is used for long term cooling. The analysis results would be useful for conducting the experiment to verify the APR 1400 extended SBO optimum mitigation strategy using outside cooling water injection in future. The pre-test calculation for ATLAS extended SBO with RCP seal leakage and outside cooling water injection scenario is performed. After Fukushima nuclear accident, the capability of coping with the extended station blackout (SBO) becomes important. Many NPPs are applying FLEX approach as main coping strategies for extended SBO scenarios. In FLEX strategies, outside cooling water injection to reactor cooling system (RCS) and steam generators (SGs) is considered as an effective method to remove residual heat and maintain the inventory of the systems during the accident. It is worthwhile to examine the soundness of outside cooling water injection method for extended SBO mitigation by both calculation and experimental demonstration. From the calculation results, outside cooling water injection into RCS and SGs is verified as an effective method during extended SBO when RCS and SGs depressurization is sufficiently performed.

Helium/solid powder O-ring leakage correlation experiments using a radiotracer

International Nuclear Information System (INIS)

Bild, R.W.; Leisher, W.B.; Weissman, S.H.; Seya, M.

1984-01-01

UO 2 definitely leaked past the O-ring in three of the tests confirming the major results of the previous work. Continuous leakage at these levels may require additional precautions under present regulatory policies. The mechanism and the time and particle size dependence for the leakage are not known, but there is some indication leakage is more likely at low temperatures. It is possible leakage is due to movement of the O-ring during temperature or pressure cycling at the beginning or end of a test. The radiotracer method involves less labor and is much less susceptible to contamination than the previous method. Future work will investigate leakage past lubricated O-rings and time dependence of leakage. 1 reference, 1 table

An objective comparison of leakage between commonly used earplugs.

Science.gov (United States)

Alt, Jeremiah A; Collins, William O

2012-01-01

We sought to determine the efficacy of commonly used earplugs using an anatomically correct ear model. The total volume and rate of water that leaked past the earplug and subsequent defect in the tympanic membrane over separately measured 30, 60, 120, and 180-second intervals were recorded. Scenarios tested included a control with no earplug, custom molded earplug (Precision Laboratories, Orlando, FL), Mack's plug (Warren, MI), Doc's plug (Santa Cruz, CA), and cotton balls coated with petroleum jelly. All plugs tested resulted in less leakage at all time points when compared with no plug (P leakage when compared with the cotton ball coated with petroleum jelly (P leakage compared with the customized plug (P leakage than the cotton plug (P leakage rate (f(4,45) = 94 [P water exposure should be minimized, then use of earplugs, particularly the moldable variety, merits further consideration. Copyright © 2012 Elsevier Inc. All rights reserved.

[Bile leakage after liver resection: A retrospective cohort study].

Science.gov (United States)

Menclová, K; Bělina, F; Pudil, J; Langer, D; Ryska, M

2015-12-01

Many previous reports have focused on bile leakage after liver resection. Despite the improvements in surgical techniques and perioperative care the incidence of this complication rather keeps increasing. A number of predictive factors have been analyzed. There is still no consensus regarding their influence on the formation of bile leakage. The objective of our analysis was to evaluate the incidence of bile leakage, its impact on mortality and duration of hospitalization at our department. At the same time, we conducted an analysis of known predictive factors. The authors present a retrospective review of the set of 146 patients who underwent liver resection at the Department of Surgery of the 2nd Faculty of Medicine of the Charles University and Central Military Hospital Prague, performed between 20102013. We used the current ISGLS (International Study Group of Liver Surgery) classification to evaluate the bile leakage. The severity of this complication was determined according to the Clavien-Dindo classification system. Statistical significance of the predictive factors was determined using Fishers exact test and Students t-test. The incidence of bile leakage was 21%. According to ISGLS classification the A, B, and C rates were 6.5%, 61.2%, and 32.3%, respectively. The severity of bile leakage according to the Clavien-Dindo classification system - I-II, IIIa, IIIb, IV and V rates were 19.3%, 42%, 9.7%, 9.7%, and 19.3%, respectively. We determined the following predictive factors as statistically significant: surgery for malignancy (pBile leakage significantly prolonged hospitalization time (pbile leakage the perioperative mortality was 23 times higher (pBile leakage is one of the most serious complications of liver surgery. Most of the risk factors are not easily controllable and there is no clear consensus on their influence. Intraoperative leak tests could probably reduce the incidence of bile leakage. In the future, further studies will be required to improve

Land-use Leakage

Energy Technology Data Exchange (ETDEWEB)

Calvin, Katherine V.; Edmonds, James A.; Clarke, Leon E.; Bond-Lamberty, Benjamin; Kim, Son H.; Wise, Marshall A.; Thomson, Allison M.; Kyle, G. Page

2009-12-01

Leakage occurs whenever actions to mitigate greenhouse gas emissions in one part of the world unleash countervailing forces elsewhere in the world so that reductions in global emissions are less than emissions mitigation in the mitigating region. While many researchers have examined the concept of industrial leakage, land-use policies can also result in leakage. We show that land-use leakage is potentially as large as or larger than industrial leakage. We identify two potential land-use leakage drivers, land-use policies and bioenergy. We distinguish between these two pathways and run numerical experiments for each. We also show that the land-use policy environment exerts a powerful influence on leakage and that under some policy designs leakage can be negative. International “offsets” are a potential mechanism to communicate emissions mitigation beyond the borders of emissions mitigating regions, but in a stabilization regime designed to limit radiative forcing to 3.7 2/m2, this also implies greater emissions mitigation commitments on the part of mitigating regions.

Method to detect steam generator tube leakage

International Nuclear Information System (INIS)

Watabe, Kiyomi

1994-01-01

It is important for plant operation to detect minor leakages from the steam generator tube at an early stage, thus, leakage detection has been performed using a condenser air ejector gas monitor and a steam generator blow down monitor, etc. In this study highly-sensitive main steam line monitors have been developed in order to identify leakages in the steam generator more quickly and accurately. The performance of the monitors was verified and the demonstration test at the actual plant was conducted for their intended application to the plants. (author)

Leakage Testing for Different Adhesive Systems and Composites to ...

African Journals Online (AJOL)

2015-11-16

Nov 16, 2015 ... resin composite, the fifth group – two‑stage SE adhesive applied and cavities filled with ... KEYWORDS: Adhesives, composite, evaluation, leakage ... the glass ionomers. ... systems are realized in one or two clinical step(s).[5].

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

Introduction to Test Facility for Iodine Retention in Filtered Containment Venting System

Energy Technology Data Exchange (ETDEWEB)

Jung, Jaehoon; An, Sang Mo; Ha, Kwang Soon; Kim, Hwan Yeol [KAERI, Daejeon (Korea, Republic of)

2015-05-15

In many countries the implementation of FCVS's is under discussion to mitigate fission product release not only in the short-term but also in the long-term view. To verify the performance of FCVS, the large-scaled tests have been performed such as advanced containment experiments (ACE), the iodine and aerosol retention rate test facility (JAVA), etc. The elemental and organic iodides are the main gaseous iodine species in the containment atmosphere. For the iodine retention, experimental programs have confirmed the existence of gaseous organic iodine in some cases in higher concentrations than for gaseous molecular iodine (I{sub 2}). The Reaction of Methyl iodide (CH{sub 3}I) with surfaces and the removal by containment filters and scrubbers is less efficient in comparison to molecular iodine. In the recent years, an experimental and analytical work has been conducted at the Paul Scherrer Institute (PSI) to develop a process leading to a fast, comprehensive and reliable retention of volatile iodine species in aqueous solutions. New FCVS test facility to verify the performance of FCVS is designed and under construction. The iodine retention tests are planned with elemental iodine or with organic iodide loaded carrier gas consisting of pure non-condensable gas, pure steam and of typical mixtures of non-condensable gas/steam. This paper introduces the iodine generation and measurement system for the iodine retention test of FCVS. In severe accidents elemental and organic iodides are the main gaseous iodine species in the containment atmosphere. Release of the gaseous species in sufficient quantities from containment to environment generates a risk for public health. The filtered containment venting systems (FCVS) can considerably reduce the leakage of radioactive materials to the environment. New integral test facility is prepared to verify a performance of the FCVS. The test facility consists of a test vessel, thermal-hydraulic, and aerosol/iodine generation and

Forest Carbon Leakage Quantification Methods and Their Suitability for Assessing Leakage in REDD

Directory of Open Access Journals (Sweden)

Sabine Henders

2012-01-01

Full Text Available This paper assesses quantification methods for carbon leakage from forestry activities for their suitability in leakage accounting in a future Reducing Emissions from Deforestation and Forest Degradation (REDD mechanism. To that end, we first conducted a literature review to identify specific pre-requisites for leakage assessment in REDD. We then analyzed a total of 34 quantification methods for leakage emissions from the Clean Development Mechanism (CDM, the Verified Carbon Standard (VCS, the Climate Action Reserve (CAR, the CarbonFix Standard (CFS, and from scientific literature sources. We screened these methods for the leakage aspects they address in terms of leakage type, tools used for quantification and the geographical scale covered. Results show that leakage methods can be grouped into nine main methodological approaches, six of which could fulfill the recommended REDD leakage requirements if approaches for primary and secondary leakage are combined. The majority of methods assessed, address either primary or secondary leakage; the former mostly on a local or regional and the latter on national scale. The VCS is found to be the only carbon accounting standard at present to fulfill all leakage quantification requisites in REDD. However, a lack of accounting methods was identified for international leakage, which was addressed by only two methods, both from scientific literature.

Blower-door techniques for measuring interzonal leakage

Energy Technology Data Exchange (ETDEWEB)

Hult, Erin L.; Sherman, Max H.; Walker, Iain

2013-01-01

Abstract The standard blower door test methods, such as ASTM E779, describe how to use a single blower door to determine the total leakage of a single-zone structure such as a detached single-family home. There are no standard test methods for measuring interzonal leakage in a two-zone or multi-zone building envelope such as might be encountered in with an attached garage or in a multifamily building. Some practitioners have been using techniques that involve making multiple measurements with a single blower door as well as combined measurements using multiple blower doors. Even for just two zones there are dozens of combinations of one-door and two-door test protocols that could conceivably be used to determine the interzonal air tightness. We examined many of these two-zone configurations using both simulation and measured data to estimate the accuracy and precision of each technique for realistic measurement scenarios. We also considered the impact of taking measurements at a single pressure versus over multiple pressures. We compared the various techniques and evaluated them for specific uses. Some techniques work better in one leakage regime; some are more sensitive to wind and other noise; some are more suited to determining only a subset of the leakage values. This paper makes recommendations on which techniques to use or not use for various cases and provides data that could be used to develop future test methods.

Failure analysis of leakage current in plastic encapsulated packages

International Nuclear Information System (INIS)

Hu, S.J.; Cheang, F.T.

1989-12-01

Plastic encapsulated packages exhibit high leakage current after a few hundred hours steam pressure pot test. The present study investigates two possible sources of leakage current, the mold compound and the lead frame tape used for taping the lead frame fingers. The results of the study indicate that the leakage current is independent of the frame and is not caused by the mold compound. The data further indicates that it is the ionic contents and acrylic-based adhesive layer of the lead frame tapes which cause the leakage current. To eliminate the leakage current, lead frame tape with low ionic contents and non acrylic-based adhesive should be used. (author). 1 fig., 2 tabs, 3 graphs

Numerical and experimental study of the leakage flow in guide vanes with different hydrofoils

Directory of Open Access Journals (Sweden)

Sailesh Chitrakar

2017-07-01

Full Text Available Clearance gaps between guide vanes and cover plates of Francis turbines tend to increase in size due to simultaneous effect of secondary flow and erosion in sediment affected hydropower plants. The pressure difference between the two sides of the guide vane induces leakage flow through the gap. This flow enters into the suction side with high acceleration, disturbing the primary flow and causing more erosion and losses in downstream turbine components. A cascade rig containing a single guide vane passage has been built to study the effect of the clearance gap using pressure sensors and PIV (Particle Image Velocimetry technique. This study focuses on developing a numerical model of the test rig, validating the results with experiments and investigating the behavior of leakage flow numerically. It was observed from both CFD and experiment that the leakage flow forms a passage vortex, which shifts away from the wall while travelling downstream. The streamlines contributing to the formation of this vortex have been discussed. Furthermore, the reference guide vane with symmetrical hydrofoil has been compared with four cambered profiles, in terms of the guide vane loading and the consequent effect on the leakage flow. A dimensionless term called Leakage Flow Factor (Lff has been introduced to compare the performances of hydrofoils. It is shown that the leakage flow and its effect on increasing losses and erosion can be minimized by changing the pressure distribution over the guide vane.

The study of human bodies' impedance networks in testing leakage currents of electrical equipments

Science.gov (United States)

Zhang, Zhaohui; Wang, Xiaofei

2006-11-01

In the testing of electrical equipments' leakage currents, impedance networks of human bodies are used to simulate the current's effect on human bodies, and they are key to the preciseness of the testing result. This paper analyses and calculates three human bodies' impedance networks of measuring electric burn current, perception or reaction current, let-go current in IEC60990, by using Matlab, compares the research result of current effect thresholds' change with sine wave's frequency published in IEC479-2, and amends parameters of measuring networks. It also analyses the change of perception or reaction current with waveform by Multisim.

Severe accident testing of a personnel airlock

International Nuclear Information System (INIS)

Clauss, D.B.; Parks, M.B.; Julien, J.T.; Peters, S.W.

1988-01-01

Sandia National Laboratories (Sandia) is investigating the leakage potential of mechanical penetrations as part of a research program on containment integrity under severe accident loads for the U.S. Nuclear Regulatory Commission (NRC). Barnes et al. (1984) and Shackelford et al. (1985) identified leakage from personnel airlocks as an important failure mode of containments subject to severe accident loads. However, these studies were based on relatively simple analysis methods. The complex structural interaction between the door, gasket, and bulkhead in personnel airlocks makes analytical evaluation of leakage difficult. In order to provide data to validate methods for evaluating the leakage potential, a full-size personnel airlock was subject to simulated severe accident loads consisting of pressure and temperature up to 300 psig and 800 degrees F. The test was conducted at Chicago Bridge and Iron under contract to Sandia. The authors provide a detailed report on the test program

Experimental results from containment piping bellows subjected to severe accident conditions. Volume 1, Results from bellows tested in 'like-new' conditions

International Nuclear Information System (INIS)

Lambert, L.D.; Parks, M.B.

1994-09-01

Bellows are an integral part of the containment pressure boundary in nuclear power plants. They are used at piping penetrations to allow relative movement between piping and the containment wall, while minimizing the load imposed on the piping and wall. Piping bellows are primarily used in steel containments; however, they have received limited use in some concrete (reinforced and prestressed) containments. In a severe accident they may be subjected to pressure and temperature conditions that exceed the design values, along with a combination of axial and lateral deflections. A test program to determine the leak-tight capacity of containment penetration bellows is being conducted under the sponsorship of the US Nuclear Regulatory Commission at Sandia National Laboratories. Several different bellows geometries, representative of actual containment bellows, have been subjected to extreme deflections along with pressure and temperature loads. The bellows geometries and loading conditions are described along with the testing apparatus and procedures. A total of thirteen bellows have been tested, all in the 'like-new' condition. (Additional tests are planned of bellows that have been subjected to corrosion.) The tests showed that bellows are capable of withstanding relatively large deformations, up to, or near, the point of full compression or elongation, before developing leakage. The test data is presented and discussed

Experimental evaluation of clinical colon anastomotic leakage.

Science.gov (United States)

Pommergaard, Hans-Christian

2014-03-01

Colorectal anastomotic leakage remains a frequent and serious complication in gastrointestinal surgery. Patient and procedure related risk factors for anastomotic leakage have been identified. However, the responsible pathophysiological mechanisms are still unknown. Among these, ischemia and insufficient surgical technique have been suggested to play a central role. Animal models are valuable means to evaluate pathophysiological mechanisms and may be used to test preventive measures aiming at reducing the risk of anastomotic leakage, such as external anastomotic coating. The aim of this thesis was to: Clarify the best suited animal to model clinical anastomotic leakage in humans; Create animal models mimicking anastomotic leakage in humans induced by insufficient surgical technique and tissue ischemia; Determine the best suited coating materials to prevent anastomotic leakage. This study is a systematic review using the databases MEDLINE and Rex. MEDLINE was searched up to October 2010 to identify studies on experimental animal models of clinical colon anastomotic leakage. From the Rex database, textbooks on surgical aspects as well as gastrointestinal physiology and anatomy of experimental animals were identified. The results indicated that the mouse and the pig are the best suited animals to evaluate clinical anastomotic leakage. However, the pig model is less validated and more costly to use compared with the mouse. Most frequently, rats are used as models. However, extreme interventions are needed to create clinical leakage in these animals. The knowledge from this study formed the basis for selecting the animal species most suited for the models in the next studies. STUDY 2: In this experimental study, technically insufficient colonic anastomoses were performed in 110 C57BL/6 mice. The number of sutures in the intervention group was reduced to produce a suitable leakage rate. Moreover, the analgesia and suture material were changed in order to optimize the

Radiation leakage in nuclear ship 'MUTSU'

International Nuclear Information System (INIS)

Ando, Yoshio; Miyasaka, Shun-ichi; Takeuchi, Kiyoshi.

1975-01-01

Associated with the radiation leakage in MUTSU occurred in September 1974, this report reviews the shielding design for MUTSU, radiation measurement and inspection activities by a survey group, and 2 dimensional analysis on the behavior of fast neutrons to shielding based on Ssub(N) codes. In the first part, the purpose and the structure of the primary and the secondary shields of MUTSU are briefly illustrated. In the second part, the progress of the series of affairs is explained, starting from zero power criticality experiment, through discovery of radiation leakage in output-increasing test, sending of a survey group for various measurement and inspection, and finally to the conclusion drawn by the survey group. In the third part, various numerical analyses performed to investigate into the leakage are illustrated with their results. The transport codes used were ANISN, TWOTRAN, SPAN, and PALLAS-2DCY. As a result of those inspection and calculation, it was found that the radiation leakage was due to fast neutrons coming through the gap between the reactor vessel and the primary shield. (Aoki, K.)

Valve leakage inspection testing and maintenance process

International Nuclear Information System (INIS)

Aikin, J.A.; Reinwald, J.W.; Kittmer, C.A.

1991-01-01

In valve maintenance, packing rings that prevent leakage along the valve stem must periodically be replaced, either during routine maintenance or to correct a leak or valve malfunction. Tools and procedures currently in use for valve packing removal and inspection are generally of limited value due to various access and application problems. A process has been developed by AECL Research that addresses these problems. The process, using incompressible fluid pressure, quickly and efficiently confirms the integrity of the valve backseat, extracts hard-to-remove valve packing sets, and verifies the leak tightness of the repacked valve

Application of Buckmaster Electrolyte Ion Leakage Test to Woody Biofuel Feedstocks

Energy Technology Data Exchange (ETDEWEB)

Broderick, Thomas F [Forest Concepts, LLC; Dooley, James H [Forest Concepts, LLC

2014-08-28

In an earlier ASABE paper, Buckmaster reported that ion conductivity of biomass leachate in aqueous solution was directly correlated with activity access to plant nutrients within the biomass materials for subsequent biological or chemical processing. The Buckmaster test involves placing a sample of the particles in a beaker of constant-temperature deionized water and monitoring the change in electrical conductivity over time. We adapted the Buckmaster method to a range of woody biomass and other cellulosic bioenergy feedstocks. Our experimental results suggest differences of electrolyte leakage between differently processed woody biomass particles may be an indicator of their utility for conversion in bioenergy processes. This simple assay appears to be particularly useful to compare different biomass comminution techniques and particle sizes for biochemical preprocessing.

Determination of leakage areas in nuclear piping

Energy Technology Data Exchange (ETDEWEB)

Keim, E. [Siemens/KWU, Erlangen (Germany)

1997-04-01

For the design and operation of nuclear power plants the Leak-Before-Break (LBB) behavior of a piping component has to be shown. This means that the length of a crack resulting in a leak is smaller than the critical crack length and that the leak is safely detectable by a suitable monitoring system. The LBB-concept of Siemens/KWU is based on computer codes for the evaluation of critical crack lengths, crack openings, leakage areas and leakage rates, developed by Siemens/KWU. In the experience with the leak rate program is described while this paper deals with the computation of crack openings and leakage areas of longitudinal and circumferential cracks by means of fracture mechanics. The leakage areas are determined by the integration of the crack openings along the crack front, considering plasticity and geometrical effects. They are evaluated with respect to minimum values for the design of leak detection systems, and maximum values for controlling jet and reaction forces. By means of fracture mechanics LBB for subcritical cracks has to be shown and the calculation of leakage areas is the basis for quantitatively determining the discharge rate of leaking subcritical through-wall cracks. The analytical approach and its validation will be presented for two examples of complex structures. The first one is a pipe branch containing a circumferential crack and the second one is a pipe bend with a longitudinal crack.

Determination of leakage areas in nuclear piping

International Nuclear Information System (INIS)

Keim, E.

1997-01-01

For the design and operation of nuclear power plants the Leak-Before-Break (LBB) behavior of a piping component has to be shown. This means that the length of a crack resulting in a leak is smaller than the critical crack length and that the leak is safely detectable by a suitable monitoring system. The LBB-concept of Siemens/KWU is based on computer codes for the evaluation of critical crack lengths, crack openings, leakage areas and leakage rates, developed by Siemens/KWU. In the experience with the leak rate program is described while this paper deals with the computation of crack openings and leakage areas of longitudinal and circumferential cracks by means of fracture mechanics. The leakage areas are determined by the integration of the crack openings along the crack front, considering plasticity and geometrical effects. They are evaluated with respect to minimum values for the design of leak detection systems, and maximum values for controlling jet and reaction forces. By means of fracture mechanics LBB for subcritical cracks has to be shown and the calculation of leakage areas is the basis for quantitatively determining the discharge rate of leaking subcritical through-wall cracks. The analytical approach and its validation will be presented for two examples of complex structures. The first one is a pipe branch containing a circumferential crack and the second one is a pipe bend with a longitudinal crack

Calculation of transformers leakage reactance using electromagnetic energy technique

International Nuclear Information System (INIS)

Feiz, J.; Mohseni, H.; Sabet Marzooghi, S.; Naderian Jahromi, A.

2004-01-01

Determination of transformer leakage reactance using magnetic cores has long been an area of interest to engineers involved in the design of power and distribution transformers. This is required for predicting the performance of transformers before actual assembly of the transformers. In this paper a closed form solution technique applicable to the leakage reactance calculations for transformers is presented. An emphasis is on the development of a simple method to calculate the leakage reactance of the distribution transformers and smaller transformers. Energy technique procedure for computing the leakage reactances in distribution transformers is presented. This method is very efficient compared with the use of flux element and image technique and is also remarkably accurate. Examples of calculated leakage inductances and the short circuit impedance are given for illustration. For validation, the results are compared with the results obtained using test. This paper presents a novel technique for calculation of the leakage inductance in different parts of the transformer using the electromagnetic stored energy

IMPACT OF DUCT LEAKAGE PRESSURES ON THE SHAPE OF THE DELTA Q CURVE

International Nuclear Information System (INIS)

Andrews, J.W.

2002-01-01

The question of whether and to what extent information on the pressures driving duct leaks can be extracted from the data taken during the Delta Q test for duct leakage is investigated. Curves of Delta Q vs. house pressure are generated for sets of cases where the supply and return leakage rates to/from outside are held constant while the leakage pressures are varied. It is found that the Delta Q curve takes on two qualitatively different shapes, one for leakage pressures within the range of house pressures used in the Delta Q test (i.e., -25 Pa to +25 Pa) and the other for leakage pressures well outside this range. These effects are seen in experimental data taken with leakage at known pressures. However, extracting the signal of the leakage pressure from the surrounding noise caused by random measurement variation is likely to be a difficult problem in many cases

Simulation and experimental research of heat leakage of cryogenic transfer lines

Science.gov (United States)

Deng, B. C.; Xie, X. J.; Pan, W.; Jiang, R. X.; Li, J.; Yang, S. Q.; Li, Q.

2017-12-01

The heat leakage of cryogenic transfer lines directly influences the performance of large-scale helium refrigerator. In this paper, a thermal model of cryogenic transfer line considering numerical simulation of support coupled with MLI was established. To validate the model, test platform of cryogenic transfer lines with the merits of disassembly outer pipe and changeable easily multi-layer insulation has been built. The experimental results of heat leakage through overall length of cryogenic transfer lines, support and multi-layer insulation were obtained. The heat leakages of multi-layer insulation, a support and the overall leakage are 1.02 W/m, 0.44 W and 1.46 W/m from experimental data, respectively. The difference of heat leakage of MLI between experiment and simulation were less than 5%. The temperature distribution of support and MLI obtained in presented model in good agreement with experimental data. It is expected to reduce the overall heat leakage of cryogenic transfer lines further by optimizing structure of support based on the above thermal model and test platform in this paper.

Evaluation of organic coatings to reduce air leakage through cracks in the Pickering NGS 'A' reactor building 1

International Nuclear Information System (INIS)

Deans, J.J.; Sato, J.A.; Hampton, J.H.D.; Cullen, R.; Paterson, G.; Chan, P.; Rajagopalan, R.

1994-01-01

Pressure tests conducted in 1992 on the Pickering NGS 'A' Reactor Building 1 showed that the containment leakage rate of the building was close to the licensing limit. The leakage was found to be pressure dependent and was attributed to cracks in the concrete dome. A number of solutions were studied by a task group, and the application of an organic coating to the exterior surface of the dome was identified as the most viable solution under the constraints of schedule and cost. In addition to reducing the air leakage rate, the coating material must be flexible to bridge existing moving cracks, it must have excellent adhesion to the concrete substrate to sustain the design pressure of 41.4 kPa(g) during pressure tests, and it must be durable for an exterior application and service conditions. Five candidate organic coating materials were selected for laboratory testing. As a result of the testing, a single-component elastomeric polyurethane coating was selected to be used on the dome. This paper discusses the selection process, laboratory tests and results, and the application of the polyurethane coating system to the exterior concrete dome surface. However, the main emphasis of the paper is on the laboratory evaluation of the five candidate materials. (author). 2 refs., 3 tabs., 1 fig

Regulatory analysis for the resolution of generic issue C---8, main steam isolation valve leakage and LCS [leakage control system] failure

International Nuclear Information System (INIS)

Graves, C.C.

1990-06-01

Generic Issue C-8 deals with staff concerns about public risk because of the incidence of leak test failures reported for main steam isolation valves (MSIVs) at boiling water reactors and the limitations of the leakage control systems (LCSs) for mitigating the consequences of leakage from these valves. If the MSIV leakage is greatly in excess of the allowable value in the technical specifications, the LCS would be unavailable because of design limitations. The issue was initiated in 1983 to assess (1) the causes of MSIV leakage failures, (2) the effectiveness of the LCS and alternative mitigation paths, and (3) the need for additional regulatory action to reduce public risk. This report presents the regulatory analysis for Generic Issue C-8 and concludes that no new regulatory requirements are warranted

Experimental results from containment piping bellows subjected to severe accident conditions: Results from bellows tested in corroded conditions. Volume 2

International Nuclear Information System (INIS)

Lambert, L.D.; Parks, M.B.

1995-10-01

Bellows are an integral part of the containment pressure boundary in nuclear power plants. They are used at piping penetrations to allow relative movement between piping and the containment wall, while minimizing the load imposed on the piping and wall. Piping bellows are primarily used in steel containments; however, they have received limited use in some concrete (reinforced and prestressed) containments. In a severe accident they may be subjected to pressure and temperature conditions that exceed the design values, along with a combination of axial and lateral deflections. A test program to determine the leak-tight capacity of containment penetration bellows is being conducted at Sandia National Laboratories under the sponsorship of the US Nuclear Regulatory Commission. Several different bellows geometries, representative of actual containment bellows, have been subjected to extreme deflections along with pressure and temperature loads. The bellows geometries and loading conditions are described along with the testing apparatus and procedures. A total of nineteen bellows have been tested. Thirteen bellows were tested in ''like-new'' condition (results reported in Volume 1), and six were tested in a corroded condition. The tests showed that bellows in ''like-new'' condition are capable of withstanding relatively large deformations, up to, or near, the point of full compression or elongation, before developing leakage, while those in a corroded condition did not perform as well, depending on the amount of corrosion. The corroded bellows test program and results are presented in this report

A method for determining leakage of 133Xe gas from septum-sealed glass vials

International Nuclear Information System (INIS)

McAllister, J.R.; Borak, T.B.; Pellicciarini, D.W.

2000-01-01

The authors have developed a method for determining the leakage of 133 Xe gas from septum-sealed glass vials that are supplied for medical examinations. Twenty vials each originally containing 370 MPq of 133 Xe and 20 vials each originally containing 740 MBq 133 Xe were measured daily for 26 d. Retention of 133 Xe within the vial was modeled as a first order process with a constant rate coefficient, λ T . The value of λ T was estimated for each vial using a regression analysis. The leakage rate, λ L , was then determined assuming that λ L = λ L + λ r where λ r represents the physical decay of 133 Xe. Monte Carlo simulations were performed using uncertainties in the estimates of each vial to obtain the mean and tails of the distribution for the average leakage rate, bar λ L . the average leakage rate for the complete sample of vials was 0.00007 d -1 with an upper, one-sided, 95% confidence limit of 0.0011 d -1 . Uncertainties in the published values of λ r for 133 Xe made a significant contribution to the uncertainties of the leakage rate for this sample of vials. The methods described can be applied to other situations where leakage of radioactive materials may be of concern

Technology evaluation for space station atmospheric leakage

Energy Technology Data Exchange (ETDEWEB)

Lemon, D.K.; Friesel, M.A.; Griffin, J.W.; Skorpik, J.R.; Shepard, C.L.; Antoniak, Z.I.; Kurtz, R.J.

1990-02-01

A concern in operation of a space station is leakage of atmosphere through seal points and through the walls as a result of damage from particle (space debris and micrometeoroid) impacts. This report describes a concept for a monitoring system to detect atmosphere leakage and locate the leak point. The concept is based on analysis and testing of two basic methods selected from an initial technology survey of potential approaches. 18 refs., 58 figs., 5 tabs.

Practical Leakage-Resilient Symmetric Cryptography

DEFF Research Database (Denmark)

Faust, Sebastian; Pietrzak, Krzysztof; Schipper, Joachim

2012-01-01

Leakage resilient cryptography attempts to incorporate side-channel leakage into the black-box security model and designs cryptographic schemes that are provably secure within it. Informally, a scheme is leakage-resilient if it remains secure even if an adversary learns a bounded amount of arbitr......Leakage resilient cryptography attempts to incorporate side-channel leakage into the black-box security model and designs cryptographic schemes that are provably secure within it. Informally, a scheme is leakage-resilient if it remains secure even if an adversary learns a bounded amount...

Model for Electromagnetic Information Leakage

OpenAIRE

Mao Jian; Li Yongmei; Zhang Jiemin; Liu Jinming

2013-01-01

Electromagnetic leakage will happen in working information equipments; it could lead to information leakage. In order to discover the nature of information in electromagnetic leakage, this paper combined electromagnetic theory with information theory as an innovative research method. It outlines a systematic model of electromagnetic information leakage, which theoretically describes the process of information leakage, intercept and reproduction based on electromagnetic radiation, and ana...

Investigations of leakage behaviour of big containers and devices

International Nuclear Information System (INIS)

Czeschik, H.

1984-12-01

Extrapolation models were improved and expanded and the statements on the leaks' relationship to pressure published in the literature were discussed. They should be regarded as aids in the determination and extrapolation of leaks on reactor safety vessels. The responsible factors for this were examined. Measuring processes which can be evaluated quantitatively, such as absolute pressure, comparison container or feed methods permit one to show leak rates down to 0.5 per mille per day. Conventional leak measurement and density test processes are compared. (DG) [de

Feasibility of a tracer gas technique for containment leakage characterization at Bruce NGS

International Nuclear Information System (INIS)

Singh, V.P.

1985-11-01

Methods for tracer gas test have been conceived and are proposed for use in conjunction with other techniques used during off-power pressurization tests. During pressurization tests is appears possible to quantify leaks through containment boundaries which make up one of the walls in adjacent rooms but quantification of leaks to open areas will require further development. Several gases may be used as tracers during pressurization tests but the preferred tracer gas is sulphur hexafluoride (SF 6 ) at an in-vault concentration of 100 μL/L if open area sampling is to be carried out of 10 μL/L if only closed room sampling is to be performed. Large values of the ratio (tracer gas concentration in containment/lower detection limit) are necessary for identification of leak sites in open areas having significant ventilation flow. It is recommended that in-station trials be carried out to test the validity of this technique. In addition, a tracer gas technique for use during on-power operation is also proposed but leak site identification and quantification during on-power tests is only possible for containment boundaries which make up the wall(s) of adjacent rooms. The use of SF 6 is required for tests conducted during on-power operation. The recommended in-vault concentration is 10 μL/L. Recommendations are made for future work, including leak tests during on-power operation

An Experimental Study of Emission and Combustion Characteristics of Marine Diesel Engine in Case of Cylinder Valves Leakage

Directory of Open Access Journals (Sweden)

Kowalski Jerzy

2015-09-01

Full Text Available Presented paper shows the results of the laboratory tests on the relationship between throttling of both air intake duct and exhaust gas duct and a gaseous emission from the marine engine. The object of research is a laboratory, four-stroke, DI diesel engine, operated at loads from 50 kW to 250 kW at a constant speed equal to 750 rpm. During the laboratory tests over 50 parameters of the engine were measured with its technical condition recognized as a „working properly” and with simulated leakage of both air intake valve and exhaust gas valve on the second cylinder. The results of this laboratory research confirm that the leakage of cylinder valves causes no significant changes of the thermodynamic parameters of the engine. Simulated leakages through the inlet and exhaust valve caused a significant increase in fuel consumption of the engine. Valve leakages cause an increase of the exhaust gas temperature behind the cylinder with leakage and behind other cylinders. The exhaust gas temperature increase is relatively small and clearly visible only at low loads of the engine. The increase of the temperature and pressure of the charging air behind the intercooler were observed too. Charging air temperature is significantly higher during the engine operation with inlet valve leakage. The study results show significant increases of the CO, NOx and CO2 emission for all the mentioned malfunctions. The conclusion is that the results of measurements of the composition of the exhaust gas may contain valuable diagnostic information about the technical condition of the air intake duct and the exhaust gas duct of the marine engine.

HUMOS monitoring system of leaks into the containment atmosphere

International Nuclear Information System (INIS)

Matal, O.; Zaloudek, J.; Matal, O. Jr.; Klinga, J.; Brom, J.

1997-01-01

The detection and monitoring of coolant leaks into the containment atmosphere during reactor operation is a major safety measure. Using the HUMOS monitoring system, leaks can be detected in pressure tests of integrity and in any other mode of operation when the reactor ventilation system is operating and the primary circuit and its components are pressurized. Performance tests, the design, hardware and software of the HUMOS system are briefly described. A test was performed to demonstrate that a small amount of humidity released by leakage into the containment air can be detected. (M.D.)

Universal leakage elimination

International Nuclear Information System (INIS)

Byrd, Mark S.; Lidar, Daniel A.; Wu, L.-A.; Zanardi, Paolo

2005-01-01

'Leakage' errors are particularly serious errors which couple states within a code subspace to states outside of that subspace, thus destroying the error protection benefit afforded by an encoded state. We generalize an earlier method for producing leakage elimination decoupling operations and examine the effects of the leakage eliminating operations on decoherence-free or noiseless subsystems which encode one logical, or protected qubit into three or four qubits. We find that by eliminating a large class of leakage errors, under some circumstances, we can create the conditions for a decoherence-free evolution. In other cases we identify a combined decoherence-free and quantum error correcting code which could eliminate errors in solid-state qubits with anisotropic exchange interaction Hamiltonians and enable universal quantum computing with only these interactions

IN-SITU TEST EXPERIMENTAL RESEARCH ON LEAKAGE OF LARGE DIAMETER PRE-STRESSED CONCRETE CYLINDER PIPE (PCCP

Directory of Open Access Journals (Sweden)

Jianjun Luo

2016-10-01

Full Text Available In recent years, a big number of large diameter pre-stressed concrete cylinder pipe (PCCP lines have been applied to the Mid-route of the South-to-North Water Transfer Project. However, the leakage problem of PCCP causes annually heavy economic losses to our country. In such a context of situation, how to detect leaks rapidly and precisely after pipes appear cracks in water supply system has great significance. Based on the study and analysis of the characteristic structure of large diameter PCCP, a new leak detection system using fiber Bragg grating sensors, which can capture signals of water pressure change, is proposed. The feasibility, reliability and practicability of the system could be acceptable according to data achieved from in–situ tests. Moreover, the leak detection system can monitor in real-time of dynamic change of water pressure. The equations of the leakage quantity and water pressure have been presented in this paper, which can provide technical guidelines for large diameter PCCP lines maintenance.

Insulator Contamination Forecasting Based on Fractal Analysis of Leakage Current

Directory of Open Access Journals (Sweden)

Bing Luo

2012-07-01

Full Text Available In this paper, an artificial pollution test is carried out to study the leakage current of porcelain insulators. Fractal theory is adopted to extract the characteristics hidden in leakage current waveforms. Fractal dimensions of the leakage current for the security, forecast and danger zones are analyzed under four types of degrees of contamination. The mean value and the standard deviation of the fractal dimension in the forecast zone are calculated to characterize the differences. The analysis reveals large differences in the fractal dimension of leakage current under different contamination discharge stages and degrees. The experimental and calculation results suggest that the fractal dimension of a leakage current waveform can be used as a new indicator of the discharge process and contamination degree of insulators. The results provide new methods and valid indicators for forecasting contamination flashovers.

A Lift-Off-Tolerant Magnetic Flux Leakage Testing Method for Drill Pipes at Wellhead.

Science.gov (United States)

Wu, Jianbo; Fang, Hui; Li, Long; Wang, Jie; Huang, Xiaoming; Kang, Yihua; Sun, Yanhua; Tang, Chaoqing

2017-01-21

To meet the great needs for MFL (magnetic flux leakage) inspection of drill pipes at wellheads, a lift-off-tolerant MFL testing method is proposed and investigated in this paper. Firstly, a Helmholtz coil magnetization method and the whole MFL testing scheme are proposed. Then, based on the magnetic field focusing effect of ferrite cores, a lift-off-tolerant MFL sensor is developed and tested. It shows high sensitivity at a lift-off distance of 5.0 mm. Further, the follow-up high repeatability MFL probing system is designed and manufactured, which was embedded with the developed sensors. It can track the swing movement of drill pipes and allow the pipe ends to pass smoothly. Finally, the developed system is employed in a drilling field for drill pipe inspection. Test results show that the proposed method can fulfill the requirements for drill pipe inspection at wellheads, which is of great importance in drill pipe safety.

A Lift-Off-Tolerant Magnetic Flux Leakage Testing Method for Drill Pipes at Wellhead

Directory of Open Access Journals (Sweden)

Jianbo Wu

2017-01-01

Full Text Available To meet the great needs for MFL (magnetic flux leakage inspection of drill pipes at wellheads, a lift-off-tolerant MFL testing method is proposed and investigated in this paper. Firstly, a Helmholtz coil magnetization method and the whole MFL testing scheme are proposed. Then, based on the magnetic field focusing effect of ferrite cores, a lift-off-tolerant MFL sensor is developed and tested. It shows high sensitivity at a lift-off distance of 5.0 mm. Further, the follow-up high repeatability MFL probing system is designed and manufactured, which was embedded with the developed sensors. It can track the swing movement of drill pipes and allow the pipe ends to pass smoothly. Finally, the developed system is employed in a drilling field for drill pipe inspection. Test results show that the proposed method can fulfill the requirements for drill pipe inspection at wellheads, which is of great importance in drill pipe safety.

Experimental evaluation of clinical colon anastomotic leakage

DEFF Research Database (Denmark)

Pommergaard, Hans-Christian

2014-01-01

, whereas the eight-suture control anastomoses had a 0% leakage rate. Furthermore, the use of absorbable suture together with voluntarily ingested Temgesic in chocolate spread as analgesic regimen were feasible. This model may be used to test the leakage reducing potential of coating materials. STUDY 3...... experimental, in which designs were not comparable and many results were contradictory. In a clinical study, a non-significant benefit of fibrin sealant was found. Based on the available clinical and experimental data it was concluded that the fibrin-based sealants, such as Tisseel and Tachosil...

CONTAINMENT EVALUATION OF BREACHED AL-SNF FOR CASK TRANSPORT

International Nuclear Information System (INIS)

Vinson, D. W.; Sindelar, R. L.; Iyer, N. C.

2005-01-01

Aluminum-based spent nuclear fuel (Al-SNF) from foreign and domestic research reactors (FRR/DRR) is being shipped to the Savannah River Site. To enter the U.S., the cask with loaded fuel must be certified to comply with the requirements in the Title 10 of the U.S. Code of Federal Regulations, Part 71. The requirements include demonstration of containment of the cask with its contents under normal and accident conditions. Al-SNF is subject to corrosion degradation in water storage, and many of the fuel assemblies are ''failed'' or have through-clad damage. A methodology has been developed with technical bases to show that Al-SNF with cladding breaches can be directly transported in standard casks and maintained within the allowable release rates. The approach to evaluate the limiting allowable leakage rate, L R , for a cask with breached Al-SNF for comparison to its test leakage rate could be extended to other nuclear material systems. The approach for containment analysis of Al-SNF follows calculations for commercial spent fuel as provided in NUREG/CR-6487 that adopts ANSI N14.5 as a methodology for containment analysis. The material-specific features and characteristics of damaged Al-SNF (fuel materials, fabrication techniques, microstructure, radionuclide inventory, and vapor corrosion rates) that were derived from literature sources and/or developed in laboratory testing are applied to generate the four containment source terms that yield four separate cask cavity activity densities; namely, those from fines; gaseous fission product species; volatile fission product species; and fuel assembly crud. The activity values, A 2 , are developed per the guidance of 10CFR71. The analysis is performed parametrically to evaluate maximum number of breached assemblies and exposed fuel area for a proposed shipment in a cask with a test leakage rate

Functions and requirements for single-shell tank leakage mitigation

International Nuclear Information System (INIS)

Cruse, J.M.

1994-01-01

This document provides the initial functions and requirements for the leakage mitigation mission applicable to past and potential future leakage from the Hanford Site's 149 single-shell high-level waste tanks. This mission is a part of the overall mission of the Westinghouse Hanford Company Tank Waste Remediation System division to remediate the tank waste in a safe and acceptable manner. Systems engineering principles are being applied to this effort. A Mission Analysis has been completed, this document reflects the next step in the systems engineering approach to decompose the mission into primary functions and requirements. The functions and requirements in this document apply to mitigative actions to be taken regarding below ground leaks from SST containment boundaries and the resulting soil contamination. Leakage mitigation is invoked in the TWRS Program in three fourth level functions: (1) Store Waste, (2) Retrieve Waste, and (3) Disposition Excess Facilities

Investigation of conditions inside the reactor building annulus of a PWR plant of KONVOI type in case of severe accidents with increased containment leakages

International Nuclear Information System (INIS)

Bakalov, Ivan; Sonnenkalb, Martin

2018-01-01

Improvements of the implemented severe accident management (SAM) concepts have been done in all operating German NPPs after the Fukushima Daiichi accidents following recommendations of the German Reactor Safety Commission (RSK) and as a result of the stress test being performed. The efficiency of newly developed severe accident management guidelines (SAMG) for a PWR KONVOI reference plant related to the mitigation of challenging conditions inside the reactor building (RB) annulus due to increased containment leakages during severe accidents have been assessed. Based on two representative severe accident scenarios the releases of both hydrogen and radionuclides into the RB annulus have been predicted with different boundary conditions. The accident scenarios have been analysed without and with the impact of several SAM measures (already planned or proposed in addition), which turned out to be efficient to mitigate the consequences. The work was done within the frame of a research project financially supported by the Federal Ministry BMUB.

Investigation of conditions inside the reactor building annulus of a PWR plant of KONVOI type in case of severe accidents with increased containment leakages

Energy Technology Data Exchange (ETDEWEB)

Bakalov, Ivan [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Berlin (Germany); Sonnenkalb, Martin [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Koeln (Germany)

2018-02-15

Improvements of the implemented severe accident management (SAM) concepts have been done in all operating German NPPs after the Fukushima Daiichi accidents following recommendations of the German Reactor Safety Commission (RSK) and as a result of the stress test being performed. The efficiency of newly developed severe accident management guidelines (SAMG) for a PWR KONVOI reference plant related to the mitigation of challenging conditions inside the reactor building (RB) annulus due to increased containment leakages during severe accidents have been assessed. Based on two representative severe accident scenarios the releases of both hydrogen and radionuclides into the RB annulus have been predicted with different boundary conditions. The accident scenarios have been analysed without and with the impact of several SAM measures (already planned or proposed in addition), which turned out to be efficient to mitigate the consequences. The work was done within the frame of a research project financially supported by the Federal Ministry BMUB.

Feasibility of Locating Leakages in Sewage Pressure Pipes Using the Distributed Temperature Sensing Technology.

Science.gov (United States)

Apperl, Benjamin; Pressl, Alexander; Schulz, Karsten

2017-01-01

The cost effective maintenance of underwater pressure pipes for sewage disposal in Austria requires the detection and localization of leakages. Extrusion of wastewater in lakes can heavily influence the water and bathing quality of surrounding waters. The Distributed Temperature Sensing (DTS) technology is a widely used technique for oil and gas pipeline leakage detection. While in pipeline leakage detection, fiber optic cables are installed permanently at the outside or within the protective sheathing of the pipe; this paper aims at testing the feasibility of detecting leakages with temporary introduced fiber optic cable inside the pipe. The detection and localization were tested in a laboratory experiment. The intrusion of water from leakages into the pipe, producing a local temperature drop, served as indicator for leakages. Measurements were taken under varying measurement conditions, including the number of leakages as well as the positioning of the fiber optic cable. Experiments showed that leakages could be detected accurately with the proposed methodology, when measuring resolution, temperature gradient and measurement time were properly selected. Despite the successful application of DTS for leakage detection in this lab environment, challenges in real system applications may arise from temperature gradients within the pipe system over longer distances and the placement of the cable into the real pipe system.

On the scaling of gas leakage from static seals

International Nuclear Information System (INIS)

Chivers, T.C.; Hunt, R.P.

1977-01-01

The interaction between gas leakage from static seals and eight potential variables is discussed. From a consideration of the interaction of these various parameters and the mechanical design of the seal system the importance of correctly interpreting leakage data is demonstrated. Given a situation where model experiments are necessary, this document forms a basis for the definition and interpretation of a test programme. (author)

Theory and Application of Magnetic Flux Leakage Pipeline Detection.

Science.gov (United States)

Shi, Yan; Zhang, Chao; Li, Rui; Cai, Maolin; Jia, Guanwei

2015-12-10

Magnetic flux leakage (MFL) detection is one of the most popular methods of pipeline inspection. It is a nondestructive testing technique which uses magnetic sensitive sensors to detect the magnetic leakage field of defects on both the internal and external surfaces of pipelines. This paper introduces the main principles, measurement and processing of MFL data. As the key point of a quantitative analysis of MFL detection, the identification of the leakage magnetic signal is also discussed. In addition, the advantages and disadvantages of different identification methods are analyzed. Then the paper briefly introduces the expert systems used. At the end of this paper, future developments in pipeline MFL detection are predicted.

Low-leakage, high-current power crowbar transformer

International Nuclear Information System (INIS)

Buck, R.T.; Galbraith, J.D.; Nunnally, W.C.

1979-01-01

The design, fabrication, and testing of two sizes of power crowbar transformers for the ZT-40 Toroidal Z-Pinch experiment at the Los Alamos Scientific Laboratory are described. Low-leakage transformers in series with the poloidal and the toroidal field coils are used to sustain magnetic field currents initially produced by 50-kV capacitor banks. The transformer primaries are driven by cost-effective, ignitron-switched, 10-kV high-density capacitor banks. The transformer secondaries, in series with the field coils, provide from 1,000 to 1,500 V to cancel the resistive voltage drop in the coil circuits. Prototype transformers, with a total leakage inductance measured in the secondary of 5 nH, have been tested with peak secondary currents in excess of 600 kA resulting from a 10-kV primary charge voltage. The test procedures and results and the mechanical construction details are presented

Visual Inspection of Water Leakage from Ground Penetrating Radar Radargram

Science.gov (United States)

Halimshah, N. N.; Yusup, A.; Mat Amin, Z.; Ghazalli, M. D.

2015-10-01

Water loss in town and suburban is currently a significant issue which reflect the performance of water supply management in Malaysia. Consequently, water supply distribution system has to be maintained in order to prevent shortage of water supply in an area. Various techniques for detecting a mains water leaks are available but mostly are time-consuming, disruptive and expensive. In this paper, the potential of Ground Penetrating Radar (GPR) as a non-destructive method to correctly and efficiently detect mains water leaks has been examined. Several experiments were designed and conducted to prove that GPR can be used as tool for water leakage detection. These include instrument validation test and soil compaction test to clarify the maximum dry density (MDD) of soil and simulation studies on water leakage at a test bed consisting of PVC pipe burying in sand to a depth of 40 cm. Data from GPR detection are processed using the Reflex 2D software. Identification of water leakage was visually inspected from the anomalies in the radargram based on GPR reflection coefficients. The results have ascertained the capability and effectiveness of the GPR in detecting water leakage which could help avoiding difficulties with other leak detection methods.

VISUAL INSPECTION OF WATER LEAKAGE FROM GROUND PENETRATING RADAR RADARGRAM

Directory of Open Access Journals (Sweden)

N. N. Halimshah

2015-10-01

Full Text Available Water loss in town and suburban is currently a significant issue which reflect the performance of water supply management in Malaysia. Consequently, water supply distribution system has to be maintained in order to prevent shortage of water supply in an area. Various techniques for detecting a mains water leaks are available but mostly are time-consuming, disruptive and expensive. In this paper, the potential of Ground Penetrating Radar (GPR as a non-destructive method to correctly and efficiently detect mains water leaks has been examined. Several experiments were designed and conducted to prove that GPR can be used as tool for water leakage detection. These include instrument validation test and soil compaction test to clarify the maximum dry density (MDD of soil and simulation studies on water leakage at a test bed consisting of PVC pipe burying in sand to a depth of 40 cm. Data from GPR detection are processed using the Reflex 2D software. Identification of water leakage was visually inspected from the anomalies in the radargram based on GPR reflection coefficients. The results have ascertained the capability and effectiveness of the GPR in detecting water leakage which could help avoiding difficulties with other leak detection methods.

Data leakage quantification

NARCIS (Netherlands)

Vavilis, S.; Petkovic, M.; Zannone, N.; Atluri, V.; Pernul, G.

2014-01-01

The detection and handling of data leakages is becoming a critical issue for organizations. To this end, data leakage solutions are usually employed by organizations to monitor network traffic and the use of portable storage devices. These solutions often produce a large number of alerts, whose

An assessment of the reported leakage of anthropogenic radionuclides from the underground nuclear test sites at Amchitka Island, Alaska, USA to the surface environment

International Nuclear Information System (INIS)

Dasher, Douglas; Hanson, Wayne; Read, Stan; Faller, Scott; Farmer, Dennis; Efurd, Wes; Kelley, John; Patrick, Robert

2002-01-01

Three underground nuclear tests representing approximately 15-16% of the total effective energy released during the United States underground nuclear testing program from 1951 to 1992 were conducted at Amchitka Island, Alaska. In 1996, Greenpeace reported that leakage of radionuclides, 241 Am and 239+240 Pu, from these underground tests to the terrestrial and freshwater environments had been detected. In response to this report, a federal, state, tribal and non-governmental team conducted a terrestrial and freshwater radiological sampling program in 1997. Additional radiological sampling was conducted in 1998. An assessment of the reported leakage to the freshwater environment was evaluated by assessing 3 H values in surface waters and 240 Pu/ 239 Pu ratios in various sample media. Tritium values ranged from 0.41 Bq/l±0.11 two sigma to 0.74 Bq/l±0.126 two sigma at the surface water sites sampled, including the reported leakage sites. Only at the Long Shot test site, where leakage of radioactive gases to the near-surface occurred in 1965, were higher 3 H levels of 5.8 Bq/l±0.19 two sigma still observed in 1997, in mud pit no. 3. The mean 240 Pu/ 239 Pu for all of the Amchitka samples was 0.1991±0.0149 one standard deviation, with values ranging from 0.1824±1.43% one sigma to 0.2431±6.56% one sigma. The measured 3 H levels and 240 Pu/ 239 Pu ratios in freshwater moss and sediments at Amchitka provide no evidence of leakage occurring at the sites reported by Buske and Miller (1998 Nuclear-Weapons-Free America and Alaska Community Action on Toxics, Anchorage, Ak, p. 38) and Miller and Buske (1996 Nuclear Flashback: The Return to Anchitka, p. 35). It was noted that the marine sample; 240 Pu/ 239 Pu ratios are statistically different than the global fallout ratios presented by Krey et al. (1976) and Kelley, Bond, and Beasley (1999). The additional non-fallout component 240 Pu/ 239 Pu ratio, assuming a single unique source, necessary to modify the global fallout 240

Fuel containment and damage tolerance in large composite primary aircraft structures. Phase 2: Testing

Science.gov (United States)

Sandifer, J. P.; Denny, A.; Wood, M. A.

1985-01-01

Technical issues associated with fuel containment and damage tolerance of composite wing structures for transport aircraft were investigated. Material evaluation tests were conducted on two toughened resin composites: Celion/HX1504 and Celion/5245. These consisted of impact, tension, compression, edge delamination, and double cantilever beam tests. Another test series was conducted on graphite/epoxy box beams simulating a wing cover to spar cap joint configuration of a pressurized fuel tank. These tests evaluated the effectiveness of sealing methods with various fastener types and spacings under fatigue loading and with pressurized fuel. Another test series evaluated the ability of the selected coatings, film, and materials to prevent fuel leakage through 32-ply AS4/2220-1 laminates at various impact energy levels. To verify the structural integrity of the technology demonstration article structural details, tests were conducted on blade stiffened panels and sections. Compression tests were performed on undamaged and impacted stiffened AS4/2220-1 panels and smaller element tests to evaluate stiffener pull-off, side load and failsafe properties. Compression tests were also performed on panels subjected to Zone 2 lightning strikes. All of these data were integrated into a demonstration article representing a moderately loaded area of a transport wing. This test combined lightning strike, pressurized fuel, impact, impact repair, fatigue and residual strength.

Space Shuttle Orbital Maneuvering Subsystem (OMS) Engine Propellant Leakage Ball-Valve Shaft Seals

Science.gov (United States)

Lueders, Kathy; Buntain, Nick; Fries, Joseph (Technical Monitor)

1999-01-01

Evidence of propellant leakage across ball-valve shaft seals has been noted during the disassembly of five flight engines and one test engine at the NASA Lyndon B. Johnson Space Center, White Sands Test Facility. Based on data collected during the disassembly of these five engines, the consequences of propellant leakage across the ball-valve shaft seals can be divided into four primary areas of concern: Damage to the ball-valve pinion shafts, damage to sleeved bearings inside the ball-valve and actuator assemblies, degradation of the synthetic rubber o-rings used in the actuator assemblies, and corrosion and degradation to the interior of the actuator assemblies. The exact time at which leakage across the ball-valve shaft seals occurs has not been determined, however, the leakage most likely occurs during engine firings when, depending on the specification used, ball-valve cavity pressures range as high as 453 to 550 psia. This potential pressure range for the ball-valve cavities greatly exceeds the acceptance leakage test pressure of 332 psia. Since redesign and replacement of the ball-valve shaft seals is unlikely, the near term solution to prevent damage that occurs from shaft-seal leakage is to implement a routine overhaul and maintenance program for engines in the fleet. Recommended repair, verification, and possible preventative maintenance measures are discussed in the paper.

Magnetic leakage shield of septum magnet for SPring-8 synchrotron

International Nuclear Information System (INIS)

Abe, Hiroshi; Aoki, Tsuyoshi; Fukami, Kenji

1997-01-01

This paper describes magnetic field measurements of the prototype septum magnet and countermeasure for reducing the leakage magnetic fields in the incidence and the extraction parts of the SPring-8 synchrotron. We studied and developed 'leakage magnetic shield' on the basis of the tests data got in these measurements. Consequentially, it succeeded in reducing effects of the leakage field to about 50% by installing the shield board in the magnet main body. Then, it was possible to manufacture the magnet which sufficiently held the effect of the leakage field for the electron and positron beam. In this examination, we confirmed the reproduction with the magnetic field distribution of the magnet measured in the manufacturer. We developed and produced of the septum magnets which were carried out determination of the shapes of the magnetic shielding. (author)

Containment bellows testing under extreme loads

International Nuclear Information System (INIS)

Splezter, B.L.; Lambert, L.D.; Parks, M.B.

1993-01-01

Sandia National Laboratories (SNL) is conducting several research programs to help develop validated methods for the prediction of the ultimate pressure capacity, at elevated temperatures, of light water reactor (LWR) containment structures. To help understand the ultimate pressure of the entire containment pressure boundary, each component must be evaluated. The containment pressure boundary consists of the containment shell and many access, piping, and electrical penetrations. The focus of the current research program is to study the ultimate behavior of flexible metal bellows that are used at piping penetrations. Bellows are commonly used at piping penetrations in steel containments; however, they have very few applications in concrete (reinforced or prestressed) containments. The purpose of piping bellows is to provide a soft connection between the containment shell and the pipe are attached while maintaining the containment pressure boundary. In this way, piping loads caused by differential movement between the piping and the containment shell are minimized. SNL is conducting a test program to determine the leaktight capacity of containment bellows when subjected to postulated severe accident conditions. If the test results indicate that containment bellows could be a possible failure mode of the containment pressure boundary, then methods will be developed to predict the deformation, pressure, and temperature conditions that would likely cause a bellows failure. Results from the test program would be used to validate the prediction methods. This paper provides a description of the use and design of bellows in containment piping penetrations, the types of possible bellows loadings during a severe accident, and an overview of the test program, including available test results at the time of writing

Pulsed magnetic flux leakage method for hairline crack detection and characterization

Science.gov (United States)

Okolo, Chukwunonso K.; Meydan, Turgut

2018-04-01

The Magnetic Flux leakage (MFL) method is a well-established branch of electromagnetic Non-Destructive Testing (NDT), extensively used for evaluating defects both on the surface and far-surface of pipeline structures. However the conventional techniques are not capable of estimating their approximate size, location and orientation, hence an additional transducer is required to provide the extra information needed. This research is aimed at solving the inevitable problem of granular bond separation which occurs during manufacturing, leaving pipeline structures with miniature cracks. It reports on a quantitative approach based on the Pulsed Magnetic Flux Leakage (PMFL) method, for the detection and characterization of the signals produced by tangentially oriented rectangular surface and far-surface hairline cracks. This was achieved through visualization and 3D imaging of the leakage field. The investigation compared finite element numerical simulation with experimental data. Experiments were carried out using a 10mm thick low carbon steel plate containing artificial hairline cracks with various depth sizes, and different features were extracted from the transient signal. The influence of sensor lift-off and pulse width variation on the magnetic field distribution which affects the detection capability of various hairline cracks located at different depths in the specimen is explored. The findings show that the proposed technique can be used to classify both surface and far-surface hairline cracks and can form the basis for an enhanced hairline crack detection and characterization for pipeline health monitoring.

Modelling of heterogenous neutron leakages in a nuclear reactor

International Nuclear Information System (INIS)

Wohleber, X.

1997-01-01

The TIBERE Model is a neutron leakage method based on B 1 heterogeneous transport equation resolution. In this work, we have studied the influence of the reflection mode at the boundary of the assembly. In particular the White boundary condition has been implemented in the APOLLO2 neutron transport code. We have compared the two TIBERE kinds of boundary conditions (specular and white) with the classical B 1 homogeneous leakage method in the modelling of some reactors. We have remarked the better capability of the TIBERE Model to compute voided assemblies. The white boundary condition is also able to compute a completely voided assembly and, besides, wins a factor 10 in CPU time in comparison with the specular boundary condition. These two heterogenous leakage formalisms have been tested on a partially voided experiment and have shown that the TIBERE Model can compute this kind of situation with a greater precision than the classical B 1 homogeneous leakage method, and with a shorter computational time. (author)

Evaluation of Container Closure System Integrity for Frozen Storage Drug Products.

Science.gov (United States)

Nieto, Alejandra; Roehl, Holger; Brown, Helen; Nikoloff, Jonas; Adler, Michael; Mahler, Hanns-Christian

2016-01-01

Sometimes, drug product for parenteral administration is stored in a frozen state (e.g., -20 °C or -80 °C), particularly during early stages of development of some biotech molecules in order to provide sufficient stability. Shipment of frozen product could potentially be performed in the frozen state, yet possibly at different temperatures, for example, using dry ice (-80 °C). Container closure systems of drug products usually consist of a glass vial, rubber stopper, and an aluminum crimped cap. In the frozen state, the glass transition temperature (Tg) of commonly used rubber stoppers is between -55 and -65 °C. Below their Tg, rubber stoppers are known to lose their elastic properties and become brittle, and thus potentially fail to maintain container closure integrity in the frozen state. Leaks during frozen temperature storage and transportation are likely to be transient, yet, can possibly risk container closure integrity and lead to microbial contamination. After thawing, the rubber stopper is supposed to re-seal the container closure system. Given the transient nature of the possible impact on container closure integrity in the frozen state, typical container closure integrity testing methods (used at room temperature conditions) are unable to evaluate and thus confirm container closure integrity in the frozen state. Here we present the development of a novel method (thermal physical container closure integrity) for direct assessment of container closure integrity by a physical method (physical container closure integrity) at frozen conditions, using a modified He leakage test. In this study, different container closure systems were evaluated with regard to physical container closure integrity in the frozen state to assess the suitability of vial/stopper combinations and were compared to a gas headspace method. In summary, the thermal physical container closure integrity He leakage method was more sensitive in detecting physical container closure

Automated detection of leakage in fluorescein angiography images with application to malarial retinopathy.

Science.gov (United States)

Zhao, Yitian; MacCormick, Ian J C; Parry, David G; Leach, Sophie; Beare, Nicholas A V; Harding, Simon P; Zheng, Yalin

2015-06-01

The detection and assessment of leakage in retinal fluorescein angiogram images is important for the management of a wide range of retinal diseases. We have developed a framework that can automatically detect three types of leakage (large focal, punctate focal, and vessel segment leakage) and validated it on images from patients with malarial retinopathy. This framework comprises three steps: vessel segmentation, saliency feature generation and leakage detection. We tested the effectiveness of this framework by applying it to images from 20 patients with large focal leak, 10 patients with punctate focal leak, and 5,846 vessel segments from 10 patients with vessel leakage. The sensitivity in detecting large focal, punctate focal and vessel segment leakage are 95%, 82% and 81%, respectively, when compared to manual annotation by expert human observers. Our framework has the potential to become a powerful new tool for studying malarial retinopathy, and other conditions involving retinal leakage.

Shielded container

International Nuclear Information System (INIS)

Fries, B.A.

1978-01-01

A shielded container for transportation of radioactive materials is disclosed in which leakage from the container is minimized due to constructional features including, inter alia, forming the container of a series of telescoping members having sliding fits between adjacent side walls and having at least two of the members including machine sealed lids and at least two of the elements including hand-tightenable caps

Biomembrane Permeabilization: Statistics of Individual Leakage Events Harmonize the Interpretation of Vesicle Leakage.

Science.gov (United States)

Braun, Stefan; Pokorná, Šárka; Šachl, Radek; Hof, Martin; Heerklotz, Heiko; Hoernke, Maria

2018-01-23

The mode of action of membrane-active molecules, such as antimicrobial, anticancer, cell penetrating, and fusion peptides and their synthetic mimics, transfection agents, drug permeation enhancers, and biological signaling molecules (e.g., quorum sensing), involves either the general or local destabilization of the target membrane or the formation of defined, rather stable pores. Some effects aim at killing the cell, while others need to be limited in space and time to avoid serious damage. Biological tests reveal translocation of compounds and cell death but do not provide a detailed, mechanistic, and quantitative understanding of the modes of action and their molecular basis. Model membrane studies of membrane leakage have been used for decades to tackle this issue, but their interpretation in terms of biology has remained challenging and often quite limited. Here we compare two recent, powerful protocols to study model membrane leakage: the microscopic detection of dye influx into giant liposomes and time-correlated single photon counting experiments to characterize dye efflux from large unilamellar vesicles. A statistical treatment of both data sets does not only harmonize apparent discrepancies but also makes us aware of principal issues that have been confusing the interpretation of model membrane leakage data so far. Moreover, our study reveals a fundamental difference between nano- and microscale systems that needs to be taken into account when conclusions about microscale objects, such as cells, are drawn from nanoscale models.

Developement of leakage localization technique by using acoustic signal

Energy Technology Data Exchange (ETDEWEB)

Kim, Y. H.; Jeon, J. H.; Seo, D. H.; Kim, K. W. [KAIST, Daejeon (Korea, Republic of)

2010-07-15

The objective of this research is to develop a leakage monitoring system for pipelines or valves in the secondary water system of a nuclear power plant. The system aims to detect the existence of leakage and to estimate the leak location, especially by utilizing the noise generated from the leak. It is safe, precise real-time alert system compared with the previous monitoring methods and tools such as the visual test and the thermal imaging camera. When there exists leakage in the pipeline or valves of nuclear power plant, the noise due to gas flow is radiated through leak region. That is, the secondary water system with leakage generates different noise from the system without leakage. This motivates us to measure and analyze the noise generated from the secondary water system, so as firstly to detect the existence of leakage, and secondly to estimate the leak location by using the noise source identification technique such as beamforming and acoustic holography. Especially the beamforming method models the signal from the noise source to estimate the location of source. Therefore, it is necessary to model the noise due to leakage which is dependent upon parameters. In the process of leak localization, the reflected wave due to interior walls and the measurement noise should be removed for the precise estimation. Therefore, we attempt to characterize the reflected wave and the measurement noise by modeling the interior sound field, thus to remove them and to localize the leak location with high precision

Transformerless photovoltaic inverters with leakage current and pulsating power elimination

DEFF Research Database (Denmark)

Tang, Yi; Yao, Wenli; Wang, H.

2015-01-01

This paper presents a transformerless inverter topology, which is capable of simultaneously solving leakage current and pulsating power issues in grid-connected photovoltaic (PV) systems. Without adding any additional components to the system, the leakage current caused by the PV......-to-ground parasitic capacitance can be bypassed by introducing a common mode (CM) conducting path to the inverter. The resulting ground leakage current is therefore well controlled to be below the regulation limit. Moreover, the proposed inverter can also eliminate the well-known double line frequency pulsating power....... The mechanism of leakage current suppression and the closed-loop control of pulsating power decoupling are discussed in the paper in details. A 500 W prototype was also built and tested in the laboratory, and both simulation and experimental results are finally presented to show the excellent performance...

An assessment of the reported leakage of anthropogenic radionuclides from the underground nuclear test sites at Amchitka Island, Alaska, USA to the surface environment

Energy Technology Data Exchange (ETDEWEB)

Dasher, Douglas E-mail: ddasher@envircon.state.ak.us; Hanson, Wayne; Read, Stan; Faller, Scott; Farmer, Dennis; Efurd, Wes; Kelley, John; Patrick, Robert

2002-07-01

Three underground nuclear tests representing approximately 15-16% of the total effective energy released during the United States underground nuclear testing program from 1951 to 1992 were conducted at Amchitka Island, Alaska. In 1996, Greenpeace reported that leakage of radionuclides, {sup 241}Am and {sup 239+240}Pu, from these underground tests to the terrestrial and freshwater environments had been detected. In response to this report, a federal, state, tribal and non-governmental team conducted a terrestrial and freshwater radiological sampling program in 1997. Additional radiological sampling was conducted in 1998. An assessment of the reported leakage to the freshwater environment was evaluated by assessing {sup 3} H values in surface waters and {sup 240}Pu/{sup 239}Pu ratios in various sample media. Tritium values ranged from 0.41 Bq/l{+-}0.11 two sigma to 0.74 Bq/l{+-}0.126 two sigma at the surface water sites sampled, including the reported leakage sites. Only at the Long Shot test site, where leakage of radioactive gases to the near-surface occurred in 1965, were higher {sup 3}H levels of 5.8 Bq/l{+-}0.19 two sigma still observed in 1997, in mud pit no. 3. The mean {sup 240}Pu/{sup 239}Pu for all of the Amchitka samples was 0.1991{+-}0.0149 one standard deviation, with values ranging from 0.1824{+-}1.43% one sigma to 0.2431{+-}6.56% one sigma. The measured {sup 3}H levels and {sup 240}Pu/{sup 239}Pu ratios in freshwater moss and sediments at Amchitka provide no evidence of leakage occurring at the sites reported by Buske and Miller (1998 Nuclear-Weapons-Free America and Alaska Community Action on Toxics, Anchorage, Ak, p. 38) and Miller and Buske (1996 Nuclear Flashback: The Return to Anchitka, p. 35). It was noted that the marine sample; {sup 240}Pu/{sup 239}Pu ratios are statistically different than the global fallout ratios presented by Krey et al. (1976) and Kelley, Bond, and Beasley (1999). The additional non-fallout component {sup 240}Pu/{sup 239}Pu

The Leakage determination on corrosion fretting machine

International Nuclear Information System (INIS)

Sriyono; Satmoko, Ari; Hafid, Abdul; Febrianto; Prasetio, Joko; Abtokhi; Sumarno, Edy; Handoyo, Ismu; Hidayati, Nur Rahmah; Histori

1998-01-01

Fretting machine is an experimental loop to learn fretting corrosion phenomena wich is caused by loading and vibration. On the steam generator, one of the corrosion process that's occurred, it can be caused by vibration between tubes and bending material. Because of high flow rate inside the tube, the high frequency vibration will appeared so it can make the corrosion on bending material more faster. This process can be simulate by fretting machine. This machine has already damage because of leakage. So it will be repaired by dismantling, radiography testing and redrawing. from the result of radiography, the leakage is caused by cracking on bellows seals of the dynamic main support

Air Leakage and Air Transfer Between Garage and Living Space

Energy Technology Data Exchange (ETDEWEB)

Rudd, Armin [Building Science Corporation, Westford, MA (United States)

2014-09-01

This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed.

A new on-line leakage current monitoring system of ZnO surge arresters

International Nuclear Information System (INIS)

Lee, Bok-Hee; Kang, Sung-Man

2005-01-01

This paper presents a new on-line leakage current monitoring system of zinc oxide (ZnO) surge arresters. To effectively diagnose the deterioration of ZnO surge arresters, a new algorithm and on-line leakage current detection device, which uses the time-delay addition method, for discriminating the resistive and capacitive currents was developed to use in the aging test and durability evaluation for ZnO arrester blocks. A computer-based measurement system of the resistive leakage current, the on-line monitoring device can detect accurately the leakage currents flowing through ZnO surge arresters for power frequency ac applied voltages. The proposed on-line leakage current monitoring device of ZnO surge arresters is more highly sensitive and gives more linear response than the existing devices using the detection method of the third harmonic leakage currents. Therefore, the proposed leakage current monitoring device can be useful for predicting the defects and performance deterioration of ZnO surge arresters in power system applications

Investigation of primary-to-secondary leakage accident on the PSB-VVER integral test facility

International Nuclear Information System (INIS)

Lipatov, I.A.; Dremin, G.I.; Galtchanskaya, S.A.; Chmal, I.I.; Moloshnikov, A.S.; Gorbunov, Y.S.; Antonova, A.I.; Elkin, I.V.

2001-01-01

The full text follows. The paper presents the main results from the test on primary-to-secondary leakage of 100 mm in equivalent diameter. The test was performed on the PSB-VVER integral test facility. PSB-VVER is a 4-loops scaled down model of primary system of NPP with VVER-1000 Russian type reactor. Volume - power scale is about 1/300 while elevation scale is 1/1. All components of the primary system of the reference NPP are modeled on PSB-VVER. Both passive (accumulators) and active (high and low pressure) ECCSs, pressurizer spray and relief circuits, feed water system and atmospheric dumping system (ADS) as well as the primary circuit gas remove emergency system are also simulated. The primary-to-secondary leakage was simulated using an external break line which connects the upper part of the hot header to SG water volume. The break line included a break nozzle (a cylindrical channel d = 5.8 mm, l/d = 10 with sharp inlet edge), quick-acting valve and two-phase mass flow rate measurement system. In addition loss of off-site power at the moment when a scram-signal is generated was assumed in the experiment. Thus the accident is to be considered as a beyond-design-basic one. The loss of off-site power results in the following: -main circulation pump shutdown; -pressurizer heaters switching off; -HPIS water cooling flow rate and number of points of water injection are reduced The study focuses on the adequacy of the associated accident management (AM) procedure developed by EDO ''GIDROPRESS'' as a General Designer of VVER-type reactors. The AM-procedure was adopted to the PSB-VVER test facility conditions using CATHARE (France) and DINAMIKA (Russia) codes analysis. The AM-procedure in PSB-VVER is as follows: after about 30 min of the onset of the accident, when the accident type and the localization of the SG affected become evident for the operator, he closes all the main steam isolation valves, inhibits the ADS actuation in the affected SG and begins to remove

Residual Stress Testing of Outer 3013 Containers

International Nuclear Information System (INIS)

Dunn, K.

2004-01-01

A Gas Tungsten Arc Welded (GTAW) outer 3013 container and a laser welded outer 3013 container have been tested for residual stresses according to the American Society for Testing Materials (ASTM) Standard G-36-94 [1]. This ASTM standard describes a procedure for conducting stress-corrosion cracking tests in boiling magnesium chloride (MgCl2) solution. Container sections in both the as-fabricated condition as well as the closure welded condition were evaluated. Significantly large residual stresses were observed in the bottom half of the as-fabricated container, a result of the base to can fabrication weld because through wall cracks were observed perpendicular to the weld. This observation indicates that regardless of the closure weld technique, sufficient residual stresses exist in the as-fabricated container to provide the stress necessary for stress corrosion cracking of the container, at the base fabrication weld. Additionally, sufficiently high residual stresses were observed in both the lid and the body of the GTAW as well as the laser closure welded containers. The stresses are oriented perpendicular to the closure weld in both the container lid and the container body. Although the boiling MgCl2 test is not a quantitative test, a comparison of the test results from the closure welds shows that there are noticeably more through wall cracks in the laser closure welded container than in the GTAW closure welded container

Characterization of nuclear reactor containment penetrations. Preliminary report

International Nuclear Information System (INIS)

Bump, T.R.; Seidensticker, R.W.; Shackelford, M.A.; Gambhir, V.K.; McLennan, G.L.

1984-06-01

This report summarizes the survey work conducted by Argonne National Laboratory on the design and details of major penetrations in 22 nuclear power plants. The survey includes all containment types and materials in current use. It also includes details of all types of penetrations (except for electrical penetration assemblies and valves) and the seals and gaskets used in them. The report provides a test matrix for testing major penetrations and for testing seals and gaskets in order to evaluate their leakage potential under severe accident conditions

Signal-based Gas Leakage Detection for Fluid Power Accumulators in Wind Turbines

DEFF Research Database (Denmark)

Liniger, Jesper; Sepehri, Nariman; N. Soltani, Mohsen

2017-01-01

This paper describes the development and application of a signal-based fault detection method for identifying gas leakage in hydraulic accumulators used in wind turbines. The method uses Multiresolution Signal Decomposition (MSD) based on wavelets for feature extraction from a~single fluid pressure...... measurement located close to the accumulator. Gas leakage is shown to create increased variations in this pressure signal. The Root Mean Square (RMS) of the detail coefficient Level 9 from the MSD is found as the most sensitive and robust fault indicator of gas leakage. The method is verified...... on an experimental setup allowing for the replication of the conditions for accumulators in wind turbines. Robustness is tested in a multi-fault environment where gas and external fluid leakage occurs simultaneously. In total, 24 experiments are performed, which show that the method is sensitive to gas leakage...

Marginal Leakage of Class V Composite Resin Restorations

Directory of Open Access Journals (Sweden)

Maryam Khoroushi

2018-01-01

Full Text Available >Introduction: Marginal leakage is one of the significant causes of restoration failure. This in-vitro study was conducted to compare cone beam computed tomography (CBCT and dye-penetration methods for determining marginal leakage at gingival surface of class V resin composite restorations.Materials and Methods: Class V cavities were prepared on the buccal surfaces of nineteen caries-free extracted human molar teeth. Cavities were conditioned and filled. The teeth were immersed in a 50% w/w aqueous silver nitrate solution for 24 h and were taken out and rinsed with distilled water. Then, they were put into a developing solution. Whole specimens were first viewed with CBCT and were then sectioned and evaluated by stereomicroscope.Results: Measurement of agreement between CBCT and stereomicroscope revealed that 15 (78.9% teeth had score 0, 1 (5.3% tooth had score 1, and 1 (5.3% tooth had score 2 in both techniques. Measurement of agreement between CBCT and stereomicroscope techniques, in the detection of marginal leakage, was 89.5% (Kappa coefficient = 0.627, P = 0.00. The Wilcoxon paired rank test revealed no significant difference between the results of CBCT and stereomicroscope in measuring the leakage at gingival margin (P = 0.157.Conclusion: Considering the limitations of the study, there was no significant difference between the results of CBCT and stereomicroscope in measuring the leakage at gingival margin of class V composite restorations. CBCT can be used noninvasively to detect the marginal leakage of gingival wall of class V composite restorations using aqueous silver nitrate solution as a tracer.

Influence of the internal anatomy on the leakage of root canals filled with thermoplastic technique.

Science.gov (United States)

Al-Jadaa, Anas; Attin, T; Peltomäki, T; Heumann, C; Schmidlin, P R; Paquè, F

2018-04-01

The aim of this paper is to evaluate the influence of the internal anatomy on the leakage of root canals filled with the thermoplastic technique. The upper central incisors (UCI) and mesial roots of the lower molars (MRLM) (n = 12 each) were tested regarding leakage using the gas-enhanced permeation test (GEPT) after root filling. The quality of the root fillings was assessed using micro-computed tomography (μCT) by superimposing scans before and after treatment to calculate unfilled volume. The calculated void volume was compared between the groups and correlated to the measured leakage values. Data were analyzed using t test and Pearson's correlation tests (p anatomy should be considered.

Compilation of current literature on seals, closures, and leakage for radioactive material packagings

International Nuclear Information System (INIS)

Warrant, M.M.; Ottinger, C.A.

1989-01-01

This report presents an overview of the features that affect the sealing capability of radioactive material packagings currently certified by the US Nuclear Regulatory Commission. The report is based on a review of current literature on seals, closures, and leakage for radioactive material packagings. Federal regulations that relate to the sealing capability of radioactive material packagings, as well as basic equations for leakage calculations and some of the available leakage test procedures are presented. The factors which affect the sealing capability of a closure, including the properties of the sealing surfaces, the gasket material, the closure method and the contents are discussed in qualitative terms. Information on the general properties of both elastomer and metal gasket materials and some specific designs are presented. A summary of the seal material, closure method, and leakage tests for currently certified packagings with large diameter seals is provided. 18 figs., 9 tabs

Subsea Hydraulic Leakage Detection and Diagnosis

OpenAIRE

Stavenes, Thomas

2010-01-01

The motivation for this thesis is reduction of hydraulic emissions, minimizing of process emergency shutdowns, exploitation of intervention capacity, and reduction of costs. Today, monitoring of hydraulic leakages is scarce and the main way to detect leakage is the constant need for filling of hydraulic fluid to the Hydraulic Power Unit (HPU). Leakage detection and diagnosis has potential, which would be adressed in this thesis. A strategy towards leakage detection and diagnosis is given....

Overview of containment integrity test at NUPEC

International Nuclear Information System (INIS)

Takumi, K.; Yamada, T.

2004-01-01

NUPEC has started NUPEC Containment Integrity project entitled 'Proving Test on the Reliability for Reactor Containment Vessel' since June 1987. This is the project for the term of twelve years sponsored by MITI (Ministry of International Trade and Industry, Japanese Government). The test items are (1) Hydrogen mixing and distribution test, (2) Hydrogen Burning Test, (3) Iodine trapping characteristics test, and (4) Structural behavior test. Based on the test results, computer codes are verified and as the results of analysis and evaluation by the computer codes, containment integrity is to be confirmed. This paper indicates the results of hydrogen mixing and distribution test and hydrogen burning test. The NUPEC tests conducted so far suggest that hydrogen will be well mixed in the model containment vessel and the prediction by the computer code is in excellent agreement with the data. The NUPEC hydrogen burning test data is in good agreement with the FITS data at SNL that were obtained at the lower hydrogen concentration condition. (author)

Evaluation through column leaching tests of metal release from contaminated estuarine sediment subject to CO2 leakages from Carbon Capture and Storage sites

International Nuclear Information System (INIS)

Payán, M. Cruz; Galan, Berta; Coz, Alberto; Vandecasteele, Carlo; Viguri, Javier R.

2012-01-01

The pH change and the release of organic matter and metals from sediment, due to the potential CO 2 acidified seawater leakages from a CCS (Carbon Capture and Storage) site are presented. Column leaching test is used to simulate a scenario where a flow of acidified seawater is in contact with recent contaminated sediment. The behavior of pH, dissolved organic carbon (DOC) and metals As, Cd, Cr, Cu, Ni, Pb, Zn, with liquid to solid (L/S) ratio and pH is analyzed. A stepwise strategy using empirical expressions and a geochemical model was conducted to fit experimental release concentrations. Despite the neutralization capacity of the seawater-carbonate rich sediment system, important acidification and releases are expected at local scale at lower pH. The obtained results would be relevant as a line of evidence input of CCS risk assessment, in an International context where strategies to mitigate the climate change would be applied. - Highlights: ► Tier structured approach for assessment of the release of metals from sediment. ► Standard column leaching test to simulate CO 2 acidified seawater CCS leakages. ► Metal and DOC release from marine sediment in contact to CO 2 acidified seawater. ► From empirical to geochemical modeling approaches of DOC and metals release in column tests. ► Contamination line of evidence input of CCS risk assessment. - Column metal release from CO 2 acidified seawater leakages in contact with estuarine contaminated sediment in CCS sites

Acoustic emission monitoring of leakage through seal-plug in PHWR systems

Energy Technology Data Exchange (ETDEWEB)

Jha, S K; Badgujar, B P; Goswami, G L [Bhabha Atomic Research Centre, Bombay (India). Atomic Fuels Div.; Patel, R J; Bhattacharya, S; Agrawal, R G [Bhabha Atomic Research Centre, Mumbai (India). Refuelling Technology Division

1994-12-31

Acoustic Emission (AE) technique is being developed as an in-service inspection tool for monitoring the leakage through seal-plugs in Pressurised Heavy Water Reactors (PHWRs). Time as well as frequency domain analysis have been utilised during the experiment carried out at Bhabha Atomic Research Centre (BARC) using test set up simulating the pressure and temperature conditions. The work involved were to determine the temperature profile on end-fitting, effect of pressure and temperature on leakage etc. This paper discusses various relationships like signal-level vs. pressure, frequency spectrum of signal, signal-level vs. leakage based on the above experimental work. (author). 4 refs., 6 figs.

Issues behind Competitiveness and Carbon Leakage

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01

This report explores the vulnerability of heavy industry to carbon leakage and competitiveness loss. It reviews the existing literature on competitiveness and carbon leakage under uneven climate policies. It also suggests a statistical method to track carbon leakage, and applies this methodology to Phase I of the EU emissions trading scheme, for various industrial activities: iron and steel, cement, aluminium and refineries. Finally, it reviews measures to mitigate carbon leakage, as discussed in Australia, Canada, Europe, New Zealand and the US.

Leakage monitoring device and method

International Nuclear Information System (INIS)

Yamada, Izumi; Matsui, Yuji; Fujimori, Haruo.

1995-01-01

In a water leakage monitor for a steam generator, output signals from an acoustic sensor disposed in the vicinity of a region to be monitored is subjected to phasing calculation (beam forming calculation) to determine the distribution of a sound source intensity distribution. A peak is retrieved based on the distribution of the sound source intensity distribution. A correction coefficient depending on the position of the peak is multiplied to the sound source intensity. The presence or absence of leakage is determined based on the degree of the sound source intensity after the completion of correction. Namely, a relative value of sound source intensity for each of the portions in the region to be monitored is determined, and the point of the greatest sound source intensity is assumed as a leaking point, to determine the position of the leakage. An absolute value of the sound source intensity at the leaking point is determined by such a constitution that a correction coefficient depending on the position is multiplied to the intensity of the position of the peak in the distribution of the sound intensity. A threshold value for the determination of the presence or absence of the leakage can be set if a relation between an amount of the leakage previously determined experimentally and the intensity of the sound source. Then, a countermeasure can easily be taken after the detection of the leakage and a restoring operation can be carried out rapidly after the occurrence of leakage while avoiding unnecessary shutdown. (N.H.)

[Experimental study of percutaneous vertebroplasty with a novel bone void filling container system].

Science.gov (United States)

Wang, Tai-Ping; Zhang, Kui-bo; Zheng, Zhao-min; Liu, Hui; Yu, Bin-sheng

2011-04-19

To investigate vertebral augmentation with a novel reticulate bone filling container system by polymethyl methacrylate (PMMA) injection in cadaveric simulated vertebral compressive fracture and explore the effect of reticulate bone filling container on cement distribution controlling within vertebral body and the restoration of biomechanical properties after augmentation. A total of 28 freshly frozen human vertebrae specimens were randomly divided into 4 groups. After the measurements of bone mineral density (BMD) and vertebral height, each vertebra received an axle load by a MTS (material testing system) machine to test the initial strength and stiffness. Subsequently a simultaneous compressive fracture model was created to measure the stiffness and height of fractured vertebrae. Then the augmentation procedure was performed. Afterward the biomechanical properties and the vertebral height were similarly measured as pre-operatively. The expansion of bone filling container and the distribution of cement within vertebral body were morphologically observed by crossing the specimens in sagittal midline and also integrated with the radiographic results. Stiffness was significantly restored comparing with that of fractured level (P container groups while it was irregular in single-layer groups. After crossing, the double-layer version expanded well in vertebral body and could enwrap most of injected cement. There was only a little leakage near the vessel layer. But the single-layer version had a poor expansion and a large amount of cement leakage. This novel reticulate bone void filling container system with different layers may restore both the biomechanical properties and the height of fractured vertebrae. But, with the benefit of reducing cement leakage, a double-layer design can enwrap most of injected PMMA and has a brighter prospect of clinical application.

Pancreatic anastomosis leakage management following pancreaticoduodenectomy how could be manage the anastomosis leakage after pancreaticoduodenectomy?

Directory of Open Access Journals (Sweden)

Seyed Abbas Tabatabei

2015-01-01

Full Text Available Background: Pancreatic anastomosis leakage and fistula formation following pancreaticoduodenectomy (Whipple′s procedure is a common complication. Delay in timely diagnosis and proper management is associated with high morbidity and mortality. To report our experience with management of pancreatic fistula following Whipple′s procedure. Materials and Methods: In this retrospective study, medical records of 90 patients who underwent Whipple′s procedure from 2009 to 2013 at our medical center were reviewed for documents about pancreatic anastomosis leakage and fistula formation. Results: There were 15 patients who developed pancreatico-jejunal anastomosis leakage. In 6 patients (3 males and 3 females the leakage was mild (conservative therapy was administered, but in 9 patients (6 males and 3 females, there was severe leakage. For the latter group, surgical intervention was done (2 cases underwent re-anastomosis and for 7 cases pancreatico-jejunal stump ligation was done along with drainage of the location. Conclusion: In severe pancreatic anastomotic leakage, it is better to intervene surgically as soon as possible by debridement of the distal part of the pancreas and ligation of the stump with nonabsorbable suture. Furthermore, debridement of the jejunum should be done, and the stump should be ligated thoroughly along with drainage.

Colorectal Anastomotic Leakage: New perspectives

NARCIS (Netherlands)

F. Daams (Freek)

2014-01-01

markdownabstract__Abstract__ This thesis provides new perspectives on colorectal anastomotic leakages. In both experimental and clinical studies, aspects of prevention, early identification, treatment and consequences of anastomotic leakage are discussed.

Serial measurement of radiation leakage dose rates in safekeeping at the Gammaknife room

International Nuclear Information System (INIS)

Baba, Sadaaki; Nozaki, Kenichi; Toyoda, Tatsuya; Wakamatsu, Osamu; Machida, Toru

2006-01-01

We report the serial measurement of leakage dose rates in safekeeping at the Gammaknife room during the past 4 years and 9 months by scintillation survey meter. The leakage dose rates at the radiation boundaries were the same as the natural background levels. Leakage dose rates at each shield calculation point from two 90 Sr calibration sources contained in the storehouse were negligible compared with those from 60 Co sources of the Gammaknife. 60 Co sources of the Gammaknife are arranged in 201 pieces at 10 degree interval on the circumference and in five lines within an arc of 35 degrees. Its shield container is made of iron at least 43 cm thick. We got leakage dose rates less than 40% of the calculated values. We think it is caused by the difference of each actual distance and shield thickness because 60 Co sources are usually considered as a point source in the shield calculation. There are shutters opening up and down when patients go in and out to the direction of the couch. The leakage values to this direction were about twice as much as the calculated value. So, we knew the thickness of those shutters was thinner than 43 cm. The half life time of 60 Co source calculated from the serial measurements of leakage dose rates was 4.93 years on average. It is 94% of the physical half life value of 5.27 years. We judged it was acceptable considering the difficulty of measuring low dose rate level with the radiation survey meter. Very strong correlation was observed between the decrease of 60 Co dose rate acquired from one minute measurement at the center of 18 cm diameter polysterene phantom gotten from December 2000 to August 2005 and that of computation based on the physical half life time. Likewise there was strong and more correlation with leakage dose rate in the Gammaknife room. From this, we deduce the leakage dose rate decreases according to the theory of the disintegration of radioactivity with passage of time. Revised radiation related laws took effect

Investigation of primary-to-secondary leakage accident on the PSB-VVER integral test facility

Energy Technology Data Exchange (ETDEWEB)

Lipatov, I.A.; Dremin, G.I.; Galtchanskaya, S.A.; Chmal, I.I.; Moloshnikov, A.S.; Gorbunov, Y.S.; Antonova, A.I. [Electrogorsk Research and Engineering Center, EREC, Moscow (Russian Federation); Elkin, I.V. [RRC ' ' Kurchatov Institute, Moscow (Russian Federation)

2001-07-01

The full text follows. The paper presents the main results from the test on primary-to-secondary leakage of 100 mm in equivalent diameter. The test was performed on the PSB-VVER integral test facility. PSB-VVER is a 4-loops scaled down model of primary system of NPP with VVER-1000 Russian type reactor. Volume - power scale is about 1/300 while elevation scale is 1/1. All components of the primary system of the reference NPP are modeled on PSB-VVER. Both passive (accumulators) and active (high and low pressure) ECCSs, pressurizer spray and relief circuits, feed water system and atmospheric dumping system (ADS) as well as the primary circuit gas remove emergency system are also simulated. The primary-to-secondary leakage was simulated using an external break line which connects the upper part of the hot header to SG water volume. The break line included a break nozzle (a cylindrical channel d = 5.8 mm, l/d = 10 with sharp inlet edge), quick-acting valve and two-phase mass flow rate measurement system. In addition loss of off-site power at the moment when a scram-signal is generated was assumed in the experiment. Thus the accident is to be considered as a beyond-design-basic one. The loss of off-site power results in the following: -main circulation pump shutdown; -pressurizer heaters switching off; -HPIS water cooling flow rate and number of points of water injection are reduced The study focuses on the adequacy of the associated accident management (AM) procedure developed by EDO ''GIDROPRESS'' as a General Designer of VVER-type reactors. The AM-procedure was adopted to the PSB-VVER test facility conditions using CATHARE (France) and DINAMIKA (Russia) codes analysis. The AM-procedure in PSB-VVER is as follows: after about 30 min of the onset of the accident, when the accident type and the localization of the SG affected become evident for the operator, he closes all the main steam isolation valves, inhibits the ADS actuation in the affected SG

Modelling of Consequences of Biogas Leakage from Gasholder

Directory of Open Access Journals (Sweden)

Petr Trávníček

2017-03-01

Full Text Available This paper describes modelling of consequences of biogas leakage from a gasholder on agricultural biogas station. Four scenarios were selected for the purpose of this work. A rupture of gasholders membrane and instantaneous explosion of gas cloud, blast of gas with delay, emptying of whole volume of gas (without initiation and initiation of gas with Jet-Fire. Leakage of gas is modelled by special software and consequences are determined on the basis of results. The first scenario was modelled with help of equations because used software does not include an appropriate model. A farm with high building density was chosen as a model case. Biogas is replaced by methane because used software does not support modelling of dispersion of mixtures. From this viewpoint, a conservative approach is applied because biogas contains “only” approximately 60% of methane (in dependence on technology and processed material.

Test plan for N2 HEPA filters assembly shop stock used on PFP E4 exhaust system

International Nuclear Information System (INIS)

DICK, J.D.

1999-01-01

At Plutonium Finishing Plant (PFP) and Plutonium Reclamation Facility (PRF) Self-contained HEPA filters, encased in wooden frames and boxes, are installed in the E4 Exhaust Ventilation System to provide confinement of radioactive releases to the environment and confinement of radioactive contamination within designated zones inside the facility. Recently during the routine testing in-leakage was discovered downstream of the Self-contained HEPA filters boxes. This Test Plan describes the approach to conduct investigation of the root causes for the in-leakage of HEPA filters

Leakage detection in underground gas mains with radioaktive argon

International Nuclear Information System (INIS)

Schmitz, J.

1975-01-01

In the field of gas supply, radionuclide techniques are suitable for the routine monitoring of transport mains by means of highly active tracer clouds and a measuring scraper as well as for exact leakage detection in local gas distribution systems. Very good results are obtained in the case of mains lying lower than 1.5 m if the length and alignment of the pipe section allow a towing probe to be pulled through. This was investigated systematically on a model stretch under practical conditions. The attempts to detect leakages were made with the aid of the radioactive isotope 41 Ar. Under conditions close to practice concerning pipe bedding, branching, pre-pressure, and leakage diameter, a leak with leakage rates as small as approx. 1 l/min could be measured with the aid of a towing probe with a precision of +-0.5 m. This accuracy is another advantage of this method. Branching and fittings with a big dead volume do not interfere with the evaluation. The investment for this method can be compared to other physical/technical investigations on mains, e.g. weld seam tests. (orig./LN) [de

The Impact of Gas Turbine Component Leakage Fault on GPA Performance Diagnostics

Directory of Open Access Journals (Sweden)

E. L. Ntantis

2016-01-01

Full Text Available The leakage analysis is a key factor in determining energy loss from a gas turbine. Once the components assembly fails, air leakage through the opening increases resulting in a performance loss. Therefore, the performance efficiency of the engine cannot be reliably determined, without good estimates and analysis of leakage faults. Consequently, the implementation of a leakage fault within a gas turbine engine model is necessary for any performance diagnostic technique that can expand its diagnostics capabilities for more accurate predictions. This paper explores the impact of gas turbine component leakage fault on GPA (Gas Path Analysis Performance Diagnostics. The analysis is demonstrated with a test case where gas turbine performance simulation and diagnostics code TURBOMATCH is used to build a performance model of a model engine similar to Rolls-Royce Trent 500 turbofan engine, and carry out the diagnostic analysis with the presence of different component fault cases. Conclusively, to improve the reliability of the diagnostic results, a leakage fault analysis of the implemented faults is made. The diagnostic tool used to deal with the analysis of the gas turbine component implemented faults is a model-based method utilizing a non-linear GPA.

105K West Isolation Barrier Acceptance Test results

International Nuclear Information System (INIS)

McCracken, K.J.; Irwin, J.J.

1995-01-01

The objective of this document is to report and interpret the findings of the isolation barrier acceptance tests performed in 105KW/100K. The tests were performed in accordance with the test plan and acceptance test procedure. The test report contains the test data. This document compares the test data against the criteria. A discussion of the leak rate analytical characterization describes how the flow characteristics flow rate will be determined using the test data from the test report. Two modes of water loss were considered; basin and/or discharge chute leakage, and evaporation. An initial test established baseline leakage data and instrumentation performance. Test 2 evaluated the sealing performance of the isolation barrier by inducing an 11 in. (27.9 cm) level differential across the barrier. The leak rate at this 11 in. (27.9 cm) level is extrapolated to the 16 ft. (4.9 m) level differential postulated in the DBE post seismic event. If the leak rate, adjusted for evaporation and basin leakage (determined from Test 1), is less than the SAR limit of 1,500 gph (5,680 lph) at a 16 ft (4.9 m) level differential, the barriers pass the acceptance test

Binding and leakage of barium in alginate microbeads.

Science.gov (United States)

Mørch, Yrr A; Qi, Meirigeng; Gundersen, Per Ole M; Formo, Kjetil; Lacik, Igor; Skjåk-Braek, Gudmund; Oberholzer, Jose; Strand, Berit L

2012-11-01

Microbeads of alginate crosslinked with Ca(2+) and/or Ba(2+) are popular matrices in cell-based therapy. The aim of this study was to quantify the binding of barium in alginate microbeads and its leakage under in vitro and accumulation under in vivo conditions. Low concentrations of barium (1 mM) in combination with calcium (50 mM) and high concentrations of barium (20 mM) in gelling solutions were used for preparation of microbeads made of high-G and high-M alginates. High-G microbeads accumulated barium from gelling solution and contained higher concentrations of divalent ions for both low- and high-Ba exposure compared with high-G microbeads exposed to calcium solely and to high-M microbeads for all gelling conditions. Although most of the unbound divalent ions were removed during the wash and culture steps, leakage of barium was still detected during storage. Barium accumulation in blood and femur bone of mice implanted with high-G beads was found to be dose-dependent. Estimated barium leakage relevant to transplantation to diabetic patients with islets in alginate microbeads showed that the leakage was 2.5 times lower than the tolerable intake value given by WHO for high-G microbeads made using low barium concentration. The similar estimate gave 1.5 times higher than is the tolerable intake value for the high-G microbeads made using high barium concentration. To reduce the risk of barium accumulation that may be of safety concern, the microbeads made of high-G alginate gelled with a combination of calcium and low concentration of barium ions is recommended for islet transplantation. Copyright © 2012 Wiley Periodicals, Inc.

Clear corneal incision leakage after phacoemulsification--detection using povidone iodine 5%.

Science.gov (United States)

Chee, Soon-Phaik

2005-01-01

The purpose of this work was to study the incidence of clear corneal wound leakage at the conclusion of standard co-axial phacoemulsification in a prospective observational series of 100 consecutive cataract cases in a single surgeon's institutional practice. At the conclusion of standard co-axial phacoemulsification using a 2.75 mm temporal single plane clear corneal incision with a 1 mm clear corneal side-port incision, the wounds were hydrated and checked for water-tightness. Povidone iodine 5% (P-I) was then evenly dripped over the cornea and the wounds were inspected visually. Any leakage of aqueous observed was recorded. The amount of leakage was graded as small or large from each wound. Leaky wounds were further hydrated and retested with P-I until sealed. Wound integrity was reassessed on the first postoperative day by use of fluorescein. Of the 100 cases, wound leakage was observed for 31 eyes (31%)-ten main incisions, nineteen side-port incisions, and both incisions in two cases. Wound leakage was easily detected as a ribbon of clear fluid streaming from the incision amid a pool of brown solution. Povidone iodine was not observed within the tract in any incision. All wound leakage was small except for one from the main incision and two from the side-port incision. None of the eyes developed wound leakage the day after surgery and none developed endophthalmitis. In conclusion, leakage from clear corneal incisions at the conclusion of phacoemulsification occurs in almost a third of cases, predominantly from the side incision. It is easily detected by use of the P-I test.

Drop Testing Representative Multi-Canister Overpacks

Energy Technology Data Exchange (ETDEWEB)

Snow, Spencer D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Morton, Dana K. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-06-01

The objective of the work reported herein was to determine the ability of the Multi- Canister Overpack (MCO) canister design to maintain its containment boundary after an accidental drop event. Two test MCO canisters were assembled at Hanford, prepared for testing at the Idaho National Engineering and Environmental Laboratory (INEEL), drop tested at Sandia National Laboratories, and evaluated back at the INEEL. In addition to the actual testing efforts, finite element plastic analysis techniques were used to make both pre-test and post-test predictions of the test MCOs structural deformations. The completed effort has demonstrated that the canister design is capable of maintaining a 50 psig pressure boundary after drop testing. Based on helium leak testing methods, one test MCO was determined to have a leakage rate not greater than 1x10^-5 std cc/sec (prior internal helium presence prevented a more rigorous test) and the remaining test MCO had a measured leakage rate less than 1x10^-7 std cc/sec (i.e., a leaktight containment) after the drop test. The effort has also demonstrated the capability of finite element methods using plastic analysis techniques to accurately predict the structural deformations of canisters subjected to an accidental drop event.

Surface CO2 leakage during the first shallow subsurface CO2 release experiment

OpenAIRE

Lewicki, J.L.; Oldenburg, C.; Dobeck, L.; Spangler, L.

2008-01-01

A new field facility was used to study CO2 migration processes and test techniques to detect and quantify potential CO2 leakage from geologic storage sites. For 10 days starting 9 July 2007, and for seven days starting 5 August 2007, 0.1 and 0.3 t CO2 d-1, respectively, were released from a ~;100-m long, sub-water table (~;2.5-m depth) horizontal well. The spatio-temporal evolution of leakage was mapped through repeated grid measurements of soil CO2 flux (FCO2). The surface leakage onset...

Results of steel containment vessel model test

International Nuclear Information System (INIS)

Luk, V.K.; Ludwigsen, J.S.; Hessheimer, M.F.; Komine, Kuniaki; Matsumoto, Tomoyuki; Costello, J.F.

1998-05-01

A series of static overpressurization tests of scale models of nuclear containment structures is being conducted by Sandia National Laboratories for the Nuclear Power Engineering Corporation of Japan and the US Nuclear Regulatory Commission. Two tests are being conducted: (1) a test of a model of a steel containment vessel (SCV) and (2) a test of a model of a prestressed concrete containment vessel (PCCV). This paper summarizes the conduct of the high pressure pneumatic test of the SCV model and the results of that test. Results of this test are summarized and are compared with pretest predictions performed by the sponsoring organizations and others who participated in a blind pretest prediction effort. Questions raised by this comparison are identified and plans for posttest analysis are discussed

Leakage Characteristics of Dual-Cannula Fenestrated Tracheostomy Tubes during Positive Pressure Ventilation: A Bench Study

Directory of Open Access Journals (Sweden)

Thomas Berlet

2016-01-01

Full Text Available This study compared the leakage characteristics of different types of dual-cannula fenestrated tracheostomy tubes during positive pressure ventilation. Fenestrated Portex® Blue Line Ultra®, TRACOE® twist, or Rüsch® Traceofix® tracheostomy tubes equipped with nonfenestrated inner cannulas were tested in a tracheostomy-lung simulator. Transfenestration pressures and transfenestration leakage rates were measured during positive pressure ventilation. The impact of different ventilation modes, airway pressures, temperatures, and simulated static lung compliance settings on leakage characteristics was assessed. We observed substantial differences in transfenestration pressures and transfenestration leakage rates. The leakage rates of the best performing tubes were <3.5% of the delivered minute volume. At body temperature, the leakage rates of these tracheostomy tubes were <1%. The tracheal tube design was the main factor that determined the leakage characteristics. Careful tracheostomy tube selection permits the use of fenestrated tracheostomy tubes in patients receiving positive pressure ventilation immediately after stoma formation and minimises the risk of complications caused by transfenestration gas leakage, for example, subcutaneous emphysema.

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)

49 CFR 192.723 - Distribution systems: Leakage surveys.

Science.gov (United States)

2010-10-01

... following minimum requirements: (1) A leakage survey with leak detector equipment must be conducted in business districts, including tests of the atmosphere in gas, electric, telephone, sewer, and water system... survey with leak detector equipment must be conducted outside business districts as frequently as...

How to attribute market leakage to CDM projects

NARCIS (Netherlands)

Vöhringer, F.; Kuosmanen, T.K.; Dellink, R.B.

2006-01-01

Economic studies suggest that market leakage rates of greenhouse gas abatement can reach the two-digit percentage range. Although the Marrakesh Accords require Clean Development Mechanism (CDM) projects to account for leakage, most projects neglect market leakage. Insufficient leakage accounting is

CONTAIN calculations; CONTAIN-Rechnungen

Energy Technology Data Exchange (ETDEWEB)

Scholtyssek, W.

1995-08-01

In the first phase of a benchmark comparison, the CONTAIN code was used to calculate an assumed EPR accident `medium-sized leak in the cold leg`, especially for the first two days after initiation of the accident. The results for global characteristics compare well with those of FIPLOC, MELCOR and WAVCO calculations, if the same materials data are used as input. However, significant differences show up for local quantities such as flows through leakages. (orig.)

Calculation of Leakage Inductance for High Frequency Transformers

DEFF Research Database (Denmark)

Ouyang, Ziwei; Jun, Zhang; Hurley, William Gerard

2015-01-01

Frequency dependent leakage inductance is often observed. High frequency eddy current effects cause a reduction in leakage inductance. The proximity effect between adjacent layers is responsible for the reduction of leakage inductance. This paper gives a detailed analysis of high frequency leakag...

Magnetic Heat Pump Containing Flow Diverters

Science.gov (United States)

Howard, Frank S.

1995-01-01

Proposed magnetic heat pump contains flow diverters for suppression of undesired flows. If left unchecked, undesired flows mix substantial amounts of partially heated and partially cooled portions of working fluid, effectively causing leakage of heat from heated side to cooled side. By reducing leakage of heat, flow diverters increase energy efficiency of magnetic heat pump, potentially offering efficiency greater than compressor-driven refrigerator.

Reliability analysis of containment isolation systems

International Nuclear Information System (INIS)

Pelto, P.J.; Ames, K.R.; Gallucci, R.H.

1985-06-01

This report summarizes the results of the Reliability Analysis of Containment Isolation System Project. Work was performed in five basic areas: design review, operating experience review, related research review, generic analysis and plant specific analysis. Licensee Event Reports (LERs) and Integrated Leak Rate Test (ILRT) reports provided the major sources of containment performance information used in this study. Data extracted from LERs were assembled into a computer data base. Qualitative and quantitative information developed for containment performance under normal operating conditions and design basis accidents indicate that there is room for improvement. A rough estimate of overall containment unavailability for relatively small leaks which violate plant technical specifications is 0.3. An estimate of containment unavailability due to large leakage events is in the range of 0.001 to 0.01. These estimates are dependent on several assumptions (particularly on event duration times) which are documented in the report

On camera-based smoke and gas leakage detection

Energy Technology Data Exchange (ETDEWEB)

Nyboe, Hans Olav

1999-07-01

Gas detectors are found in almost every part of industry and in many homes as well. An offshore oil or gas platform may host several hundred gas detectors. The ability of the common point and open path gas detectors to detect leakages depends on their location relative to the location of a gas cloud. This thesis describes the development of a passive volume gas detector, that is, one than will detect a leakage anywhere in the area monitored. After the consideration of several detection techniques it was decided to use an ordinary monochrome camera as sensor. Because a gas leakage may perturb the index of refraction, parts of the background appear to be displaced from their true positions, and it is necessary to develop algorithms that can deal with small differences between images. The thesis develops two such algorithms. Many image regions can be defined and several feature values can be computed for each region. The value of the features depends on the pattern in the image regions. The classes studied in this work are: reference, gas, smoke and human activity. Test show that observation belonging to these classes can be classified fairly high accuracy. The features in the feature set were chosen and developed for this particular application. Basically, the features measure the magnitude of pixel differences, size of detected phenomena and image distortion. Interesting results from many experiments are presented. Most important, the experiments show that apparent motion caused by a gas leakage or heat convection can be detected by means of a monochrome camera. Small leakages of methane can be detected at a range of about four metres. Other gases, such as butane, where the densities differ more from the density of air than the density of methane does, can be detected further from the camera. Gas leakages large enough to cause condensation have been detected at a camera distance of 20 metres. 59 refs., 42 figs., 13 tabs.

Releasable activity and maximum permissible leakage rate within a transport cask of Tehran Research Reactor fuel samples

Directory of Open Access Journals (Sweden)

Rezaeian Mahdi

2015-01-01

Full Text Available Containment of a transport cask during both normal and accident conditions is important to the health and safety of the public and of the operators. Based on IAEA regulations, releasable activity and maximum permissible volumetric leakage rate within the cask containing fuel samples of Tehran Research Reactor enclosed in an irradiated capsule are calculated. The contributions to the total activity from the four sources of gas, volatile, fines, and corrosion products are treated separately. These calculations are necessary to identify an appropriate leak test that must be performed on the cask and the results can be utilized as the source term for dose evaluation in the safety assessment of the cask.

Experiments to evaluate behavior of containment piping bellows under severe accident conditions

International Nuclear Information System (INIS)

Lambert, L.D.; Parks, M.B.

1993-01-01

Bellows are an integral part of the containment pressure boundary in nuclear power plants. They are used at piping penetrations to allow relative movement between piping and the containment wall. In a severe accident they may be subjected to high pressure and temperature, and a combination of axial and lateral deflections. A test program to determine the leak-tight capacity of containment penetration bellows is being conducted at Sandia National Laboratories, Albuquerque, New Mexico. Several different bellows geometries, representative of actual containment bellows, are being subjected to extreme deflections along with pressure and temperature loads. The bellows geometries and loading conditions are described along with the testing apparatus and procedures. A total of thirteen tests have been conducted. The tests showed that withstanding relatively large bellows are capable of deformations, up to, or near, the point of full compression before developing leakage. The test data is presented and discussed

Containment analysis for Type B packages used to transport various contents

International Nuclear Information System (INIS)

Anderson, B.L.; Carlson, R.W.; Fischer, L.E.

1996-11-01

This report presents sample containment analyses and examples of leakage rate calculations for Type B packages used to transport various contents. Samples of acceptance standard leakage rates are developed for specific contents types at normal transport conditions and at hypothetical accident conditions. The leakage rates are expressed as allowable standard leakage rates. The type of contents considered include: (1) powders, (2) liquids, (3) irradiated fuel rods, (4) gases, and (5) solids

Simulation of leakage through mechanical sealing device

Science.gov (United States)

Tikhomorov, V. P.; Gorlenko, O. A.; Izmerov, M. A.

2018-03-01

The procedure of mathematical modeling of leakage through the mechanical seal taking into account waviness and roughness is considered. The percolation process is represented as the sum of leakages through a gap between wavy surfaces and percolation through gaps formed by fractal roughness, i.e. the total leakage is determined by the slot model and filtration leakage. Dependences of leaks on the contact pressure of corrugated and rough surfaces of the mechanical seal elements are presented.

Suppression and control of leakage field in electromagnetic helical microwiggler

Energy Technology Data Exchange (ETDEWEB)

Ohigashi, N. [Kansai Univ., Osaka (Japan); Tsunawaki, Y. [Osaka Sangyo Univ. (Japan); Imasaki, K. [Institute for Laser Technology, Osaka (Japan)] [and others

1995-12-31

Shortening the period of electromagnetic wiggler introduces both the radical increase of the leakage field and the decrease of the field in the gap region. The leakage field is severer problem in planar electromagnetic wiggler than in helical wiggler. Hence, in order to develop a short period electromagnetic wiggler, we have adopted {open_quotes}three poles per period{close_quotes} type electromagnetic helical microwiggler. In this work, we inserted the permanent magnet (PM) blocks with specific magnetized directions in the space between magnetic poles, for suppressing the leakage field flowing out from a pole face to the neighboring pole face. These PM-blocks must have higher intrinsic coersive force than saturation field of pole material. The gap field due to each pole is adjustable by controlling the leakage fields, that is, controlling the position of each iron screw set in each retainer fixing the PM-blocks. At present time, a test wiggler with period 7.8mm, periodical number 10 and gap length 4.6mm has been manufactured. Because the ratio of PM-block aperture to gap length is important parameter to suppress the leakage field, the parameter has been surveyed experimentally for PM-blocks with several dimensions of aperture. The field strength of 3-5kG (K=0.2-0.4) would be expected in the wiggler.

An experimental approach to determining subsurface leakage from a surface impoundment using a radioisotope tracer

International Nuclear Information System (INIS)

Ashwood, T.L.; Story, J.D.; Larsen, I.L.; Schultz, F.J.

1987-01-01

Bromine-82, a 35.3-h half-life radionuclide, was used as a tracer to determine the paths and rates of leakage from an unlined, 1,000,000-gal (3,785,000 L), surface impoundment at the Oak Ridge National Laboratory. Since the impoundment is underlain and surrounded by storm sewer and sanitary sewer lines (most of them predating the impoundment), known and suspected leak sites in storm drain catch basins and sanitary sewer manholes were sampled periodically and analyzed for 82 Br. A series of four ground water monitoring wells - three downgradient and one upgradient from the impoundment - were also sampled for 82 Br. Although the catch basin and manhole samples picked up 82 Br in leakage from the impoundment less than 5 h after application of the tracer, the monitoring well samples did not contain detectable levels of the radionuclide. It was concluded that the monitoring wells were sampling groundwater moving through the formation, whereas the storm drains and manholes were sampling water leading rapidly through secondary porosity and along preferred pathways. The decline in tracer concentration as a function of time was used to determine the residence time of water in the pond and hence the flow rate through the pond. This flow rate, when compared with the known outflow rate, indicated that the leakage flow was small. Hence, the main value of the test was to identify rapid leakage pathways. The experiment demonstrates the need for sampling subsurface drain systems as part of an integrated monitoring system for leak detection. The effectiveness of 82 Br as a tracer for rapid leaks was also shown

Air Leakage and Air Transfer Between Garage and Living Space

Energy Technology Data Exchange (ETDEWEB)

Rudd, A.

2014-09-01

This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the Baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.

Control room unfiltered in-leakage limit analysis of design-basis LOCA for Lungmen ABWR plant

International Nuclear Information System (INIS)

Tsai Chihming; Chang Chinjang; Yuann Yngruey

2014-01-01

In USNRC's Generic Letter 2003-01, 'Control Room Habitability,' it requests utilities provide information to demonstrate that the control room at each of their respective facilities complies with the current licensing and design bases, and applicable regulatory requirements, and that suitable design, maintenance and testing control measures are in place for maintaining this compliance. In particular, each utility is required to perform the control room in-leakage test to demonstrate that the unfiltered in-leakage rate is within that assumed in the licensing analyses. It must be ensured that the control room envelope habitability, in terms of radiation dose, is maintained during normal operations as well as design basis accidents. In view of this, a dose analysis has been performed to establish the control room unfiltered in-leakage limit which can be used as an acceptance criterion for the in-leakage test. The analysis in this study is for Lungmen ABWR plant. The plant has twin units, with each unit having its own control room. The TID-4844 source terms and associated methodology are used. The USNRC RADTRAD v3.03 code is employed for the transport calculation of radioactive materials in different paths, including control room in-leakage path. The radiological criterion on protection of the operators specified in 10 CFR 50, Appendix A, General Design Criterion 19 is followed. It's demonstrated that the performance of Lungmen control room with 500 cfm unfiltered in-leakage air could meet the radiological habitability acceptance criteria in case of radiation hazards. (author)

Evaluation of the Repeatability of the Delta Q Duct Leakage Testing TechniqueIncluding Investigation of Robust Analysis Techniques and Estimates of Weather Induced Uncertainty

Energy Technology Data Exchange (ETDEWEB)

Dickerhoff, Darryl; Walker, Iain

2008-08-01

The DeltaQ test is a method of estimating the air leakage from forced air duct systems. Developed primarily for residential and small commercial applications it uses the changes in blower door test results due to forced air system operation. Previous studies established the principles behind DeltaQ testing, but raised issues of precision of the test, particularly for leaky homes on windy days. Details of the measurement technique are available in an ASTM Standard (ASTM E1554-2007). In order to ease adoption of the test method, this study answers questions regarding the uncertainty due to changing weather during the test (particularly changes in wind speed) and the applicability to low leakage systems. The first question arises because the building envelope air flows and pressures used in the DeltaQ test are influenced by weather induced pressures. Variability in wind induced pressures rather than temperature difference induced pressures dominates this effect because the wind pressures change rapidly over the time period of a test. The second question needs to answered so that DeltaQ testing can be used in programs requiring or giving credit for tight ducts (e.g., California's Building Energy Code (CEC 2005)). DeltaQ modeling biases have been previously investigated in laboratory studies where there was no weather induced changes in envelope flows and pressures. Laboratory work by Andrews (2002) and Walker et al. (2004) found biases of about 0.5% of forced air system blower flow and individual test uncertainty of about 2% of forced air system blower flow. The laboratory tests were repeated by Walker and Dickerhoff (2006 and 2008) using a new ramping technique that continuously varied envelope pressures and air flows rather than taking data at pre-selected pressure stations (as used in ASTM E1554-2003 and other previous studies). The biases and individual test uncertainties for ramping were found to be very close (less than 0.5% of air handler flow) to those

Germline contamination and leakage in whole genome somatic single nucleotide variant detection.

Science.gov (United States)

Sendorek, Dorota H; Caloian, Cristian; Ellrott, Kyle; Bare, J Christopher; Yamaguchi, Takafumi N; Ewing, Adam D; Houlahan, Kathleen E; Norman, Thea C; Margolin, Adam A; Stuart, Joshua M; Boutros, Paul C

2018-01-31

The clinical sequencing of cancer genomes to personalize therapy is becoming routine across the world. However, concerns over patient re-identification from these data lead to questions about how tightly access should be controlled. It is not thought to be possible to re-identify patients from somatic variant data. However, somatic variant detection pipelines can mistakenly identify germline variants as somatic ones, a process called "germline leakage". The rate of germline leakage across different somatic variant detection pipelines is not well-understood, and it is uncertain whether or not somatic variant calls should be considered re-identifiable. To fill this gap, we quantified germline leakage across 259 sets of whole-genome somatic single nucleotide variant (SNVs) predictions made by 21 teams as part of the ICGC-TCGA DREAM Somatic Mutation Calling Challenge. The median somatic SNV prediction set contained 4325 somatic SNVs and leaked one germline polymorphism. The level of germline leakage was inversely correlated with somatic SNV prediction accuracy and positively correlated with the amount of infiltrating normal cells. The specific germline variants leaked differed by tumour and algorithm. To aid in quantitation and correction of leakage, we created a tool, called GermlineFilter, for use in public-facing somatic SNV databases. The potential for patient re-identification from leaked germline variants in somatic SNV predictions has led to divergent open data access policies, based on different assessments of the risks. Indeed, a single, well-publicized re-identification event could reshape public perceptions of the values of genomic data sharing. We find that modern somatic SNV prediction pipelines have low germline-leakage rates, which can be further reduced, especially for cloud-sharing, using pre-filtering software.

Carbon leakage from a Nordic perspective

Energy Technology Data Exchange (ETDEWEB)

Naess-Schmidt, S.; Hansen, Martin Bo; Sand Kirk, J. [Copenhagen Economics, Copenhagen (Denmark)

2012-02-15

Carbon pricing is generally considered a highly effective tool in reducing carbon emissions. Putting a price on carbon provides incentives for users and producers of fossil fuels to reduce consumption and develop low carbon products and processes. However, pursuing an ambitious climate policy can lead to carbon leakage, which refers to a situation where unilateral or regional climate change policy drives the relocation of industry investments and installations, and associated emissions, to third countries. This report by Copenhagen Economics has been commissioned by the Nordic Council of Ministers to give an overview of the industries at risk of carbon leakage in the Nordic countries, and estimate the expected extent of carbon leakage from unilateral climate policies in the Nordic countries. The report also assesses available policy options that may reduce the risk of carbon leakage, such as exemptions from energy tax and exemptions from quota obligations under green certificate schemes. The key drivers of carbon leakage are identified, which include energy intensity, product differentiation, transportation costs and capital intensity. The analysis suggests that industries such as paper and pulp, iron and steel, aluminium, cement, pharmaceuticals, chemicals, and fertilizers are most at risk of carbon leakage in the Nordic manufacturing sector. (Author)

Radiological testing of products containing radioactivity

International Nuclear Information System (INIS)

Dixon, D.W.; Knight, A.

1980-01-01

Consumer products containing radioactive substances are tested by NRPB to determine how much radioactive material is likely to be released from a product if it is misused or accidentally damaged. Such testing is briefly described with particular reference to ionisation chamber smoke detectors, liquid crystal display watches illuminated with gaseous tritium light sources and anti-static brushes containing polonium-210 in the form of ceramic microspheres. (U.K.)

Roxby Downs water leakage

International Nuclear Information System (INIS)

1996-01-01

The Environment, Resource and development Committee has been asked by Parliament to examine 'a massive leakage of water at Roxby Downs' and to make recommendations 'as to further action'. It has also been specifically asked to comment on 'the desirability of the Department of Mines and Energy having prime responsibility for environmental matters in relation to mining operations'. This report begins with a description of the Olympic Dam operations near Roxby Downs and with a brief overview of the regulations controlling those operations. The site of the leakage the Olympic Dam tailings retention system is then described in greater detail. Part 3 describes how the system was originally designed, modified and approved. It ends with a series of findings about the adequacy of the original design (including the monitoring systems built into it) and of the approvals process. Recommendations are then made about how future approvals should be handled. Part 4 of the report outlines how the tailings retention system was built and operated and how the massive leakage from it was detected and reported. Findings about the adequacy of the management of the system and about the initial reactions to the leakage are then made, together with recommendations designed to improve future management of the system. 25 refs., 15 figs

Safety Test Report for the SNF Dry Storage System

Energy Technology Data Exchange (ETDEWEB)

Bang, K. S.; Seo, K. S.; Lee, J. H.; Lee, J. C.; Choi, W. S

2008-11-15

This is technical report conducted by KAERI under the contract with NETEC for safety test for the PWR S/F dry storage system. Leak Test was performed after drop test and turn-over test, the measured leakage rate was lower than allowable leakage rate. It is revealed that the containment integrity of the dry storage system is maintained. In the seismic test, the moving of the model was measured at SRTH seismic response of 0.4 g and 0.8 g. Therefore the seismic test results can be used fully to the test data for verification of the seismic analysis. In the thermal test, the direction of the inlet and outlet of the air has no effect on the heat transfer performance. The passive heat removal system of the horizontal storage module was designed well.

Field Tests of Real-time In-situ Dissolved CO2 Monitoring for CO2 Leakage Detection in Groundwater

Science.gov (United States)

Yang, C.; Zou, Y.; Delgado, J.; Guzman, N.; Pinedo, J.

2016-12-01

Groundwater monitoring for detecting CO2 leakage relies on groundwater sampling from water wells drilled into aquifers. Usually groundwater samples are required be collected periodically in field and analyzed in the laboratory. Obviously groundwater sampling is labor and cost-intensive for long-term monitoring of large areas. Potential damage and contamination of water samples during the sampling process can degrade accuracy, and intermittent monitoring may miss changes in the geochemical parameters of groundwater, and therefore signs of CO2 leakage. Real-time in-situ monitoring of geochemical parameters with chemical sensors may play an important role for CO2 leakage detection in groundwater at a geological carbon sequestration site. This study presents field demonstration of a real-time in situ monitoring system capable of covering large areas for detection of low levels of dissolved CO2 in groundwater and reliably differentiating natural variations of dissolved CO2 concentration from small changes resulting from leakage. The sand-alone system includes fully distributed fiber optic sensors for carbon dioxide detection with a unique sensor technology developed by Intelligent Optical Systems. The systems were deployed to the two research sites: the Brackenridge Field Laboratory where the aquifer is shallow at depths of 10-20 ft below surface and the Devine site where the aquifer is much deeper at depths of 140 to 150 ft. Groundwater samples were periodically collected from the water wells which were installed with the chemical sensors and further compared to the measurements of the chemical sensors. Our study shows that geochemical monitoring of dissolved CO2 with fiber optic sensors could provide reliable CO2 leakage signal detection in groundwater as long as CO2 leakage signals are stronger than background noises at the monitoring locations.

Coolant leakage detection device

International Nuclear Information System (INIS)

Ito, Takao.

1983-01-01

Purpose: To surely detect the coolant leakage at a time when the leakage amount is still low in the intra-reactor inlet pipeway of FBR type reactor. Constitution: Outside of the intra-reactor inlet piping for introducing coolants at low temperature into a reactor core, an outer closure pipe is furnished. The upper end of the outer closure pipe opens above the liquid level of the coolants in the reactor, and a thermocouple is inserted to the opening of the upper end. In such a structure, if the coolants in the in-reactor piping should leak to the outer closure pipe, coolants over-flows from the opening thereof, at which the thermocouple detects the temperature of the coolants at a low temperature, thereby enabling to detect the leakage of the coolants at a time when it is still low. (Kamimura, M.)

The utility of 5-aminolevulinic acid-mediated photodynamic diagnosis in the detection of intraoperative bile leakage.

Science.gov (United States)

Inoue, Yoshihiro; Imai, Yoshiro; Fujii, Kensuke; Hirokawa, Fumitoshi; Hayashi, Michihiro; Uchiyama, Kazuhisa

2017-06-01

The purpose of this retrospective study was to evaluate the utility of the new intraoperative bile leakage test as a preventive measure of postoperative bile leakage. 737 patients were retrospectively analyzed with respect to the management of intra- and post-operative bile leakage. Nine (8.3%) of 109 patients evaluated using conventional white light fluorescent imaging were recognized as having intra-operative bile leakage. However, performance of 5-aminolevulinic acid (5-ALA)-mediated PDD detected bile leakage intraoperatively not only in these 9 patients, but also in an additional 6 patients, such that 'red fluorescence' at the cut surface of the liver, was visualized in a total of 15 patients. The postoperative courses of most patients were uneventful, and postoperative bile leakages occurred in only one (0.9%) patient. 5-ALA fluorescence imaging may be needed to prevent postoperative bile leakage in patients at high risk for this surgical complication after hepatic resection. Copyright © 2016 Elsevier Inc. All rights reserved.

Leak-tightness characteristics concerning the containment structures of the HTTR

International Nuclear Information System (INIS)

Sakaba, Nariaki; Iigaki, Kazuhiko; Kondo, Masaaki; Emori, Koichi

2004-01-01

The containment structures of the HTTR consist of the reactor containment vessel, the service area, and the emergency air purification system, which minimise the release of fission products in postulated accidents, which lead to fission product release from the reactor facilities. The reactor containment vessel is designed to withstand the temperature and pressure transients and to be leak-tight in the case of a rupture of the primary concentric hot-gas duct, etc. The pressure inside the service area is maintained at a negative pressure by the emergency air purification system. The emergency air purification system will also remove airborne radioactivity and will maintain a correct pressure in the service area. The leak-tightness characteristics of the containment structures are described in this paper. The measured leakage rates of the reactor containment vessel were enough less than the specified leakage limit of 0.1%/d confirmed during the commissioning tests and annual inspections. The service area was kept in a way that the design pressure becomes well below its allowable limitation by the emergency air purification system, which filters efficiency of particle removal and iodine removal well over the limited values. The obtained data demonstrate that the reactor containment structures were fabricated to minimise the release of fission products in the postulated accidents with fission product release from the reactor facilities

An Angular Leakage Correction for Modeling a Hemisphere, Using One-Dimensional Spherical Coordinates

International Nuclear Information System (INIS)

Schwinkendorf, K.N.; Eberle, C.S.

2003-01-01

A radially dependent, angular leakage correction was applied to a one-dimensional, multigroup neutron diffusion theory computer code to accurately model hemispherical geometry. This method allows the analyst to model hemispherical geometry, important in nuclear criticality safety analyses, with one-dimensional computer codes, which execute very quickly. Rapid turnaround times for scoping studies thus may be realized. This method uses an approach analogous to an axial leakage correction in a one-dimensional cylinder calculation. The two-dimensional Laplace operator was preserved in spherical geometry using a leakage correction proportional to 1/r 2 , which was folded into the one-dimensional spherical calculation on a mesh-by-mesh basis. Hemispherical geometry is of interest to criticality safety because of its similarity to piles of spilled fissile material and accumulations of fissile material in process containers. A hemisphere also provides a more realistic calculational model for spilled fissile material than does a sphere

Analysis of ONKALO water leakage mapping results

Energy Technology Data Exchange (ETDEWEB)

Ahokas, H.; Nummela, J; Turku, J. [Poeyry Finland Oy, Vantaa (Finland)

2014-04-15

As part of the programme for the final disposal of spent nuclear fuel, an analysis has been compiled of water leakage mapping performed in ONKALO. Leakage mapping is part of the Olkiluoto Monitoring Programme (OMO) and the field work has been carried out by Posiva Oy. The main objective of the study is to analyse differences detected between mapping campaigns carried out typically twice a year in 2005-2012. Differences were estimated to be caused by the differences in groundwater conditions caused by seasonal effects or by differences between the years. The effect of technical changes like shotcreting, postgrouting, ventilation etc. on the results was also studied. The development of the visualisation of mapping results was also an objective of this work. Leakage mapping results have been reported yearly in the monitoring reports of Hydrology with some brief comments on the detected differences. In this study, the development of the total area and the number of different leakages as well as the correlation of changes with shotcreting and grouting operations were studied. In addition, traces of fractures on tunnel surfaces, and the location of rock bolts and drain pipes were illustrated together with leakage mapping. In water leakage mapping, the tunnel surfaces are visually mapped to five categories: dry, damp, wet, dripping and flowing. Major changes were detected in the total area of damp leakages. It is likely that the increase has been caused by the condensation of warm ventilation air on the tunnel surfaces and the corresponding decrease by the evaporation of moisture into the dry ventilation air. Shotcreting deep in ONKALO may also have decreased the total area of damp leakages. Changes in the total area and number of wet leakages correlate at least near the surface with differences in yearly precipitation. It is possible that strong rains have also caused a temporary increase in wet leakages. Dripping and wet leakages have been observed on average more

Analysis of ONKALO water leakage mapping results

International Nuclear Information System (INIS)

Ahokas, H.; Nummela, J; Turku, J.

2014-04-01

As part of the programme for the final disposal of spent nuclear fuel, an analysis has been compiled of water leakage mapping performed in ONKALO. Leakage mapping is part of the Olkiluoto Monitoring Programme (OMO) and the field work has been carried out by Posiva Oy. The main objective of the study is to analyse differences detected between mapping campaigns carried out typically twice a year in 2005-2012. Differences were estimated to be caused by the differences in groundwater conditions caused by seasonal effects or by differences between the years. The effect of technical changes like shotcreting, postgrouting, ventilation etc. on the results was also studied. The development of the visualisation of mapping results was also an objective of this work. Leakage mapping results have been reported yearly in the monitoring reports of Hydrology with some brief comments on the detected differences. In this study, the development of the total area and the number of different leakages as well as the correlation of changes with shotcreting and grouting operations were studied. In addition, traces of fractures on tunnel surfaces, and the location of rock bolts and drain pipes were illustrated together with leakage mapping. In water leakage mapping, the tunnel surfaces are visually mapped to five categories: dry, damp, wet, dripping and flowing. Major changes were detected in the total area of damp leakages. It is likely that the increase has been caused by the condensation of warm ventilation air on the tunnel surfaces and the corresponding decrease by the evaporation of moisture into the dry ventilation air. Shotcreting deep in ONKALO may also have decreased the total area of damp leakages. Changes in the total area and number of wet leakages correlate at least near the surface with differences in yearly precipitation. It is possible that strong rains have also caused a temporary increase in wet leakages. Dripping and wet leakages have been observed on average more

Sistem Proteksi Arus Bocor Menggunakan Earth Leakage Circuit Breaker Berbasis Arduino

Directory of Open Access Journals (Sweden)

Syukriyadin Syukriyadin

2017-02-01

Full Text Available Touching a live part of electrical equipment either intentionally or unintentionally can cause an electric shock. The touch can occur directly or indirectly and results in the flow of electric current through the human body to the ground. This electric current is known as the leakage current and can have fatal effects on the human body such as burns, cramps, faint and death. This paper aims to design a prototype protection model of the earth leakage circuit breaker device based on Arduino (ELCBA to protect the human body from the electrical hazards. The performance of the ELCBA is investigated by detecting the earth leakage current to the grounding system (TN.  The prototype is designed and simulated by using Proteus software. Based on the response test carried out on the prototype, it can be concluded that the ELCBA can operate properly to disconnect the electric circuit if the leakage current is detected greater than or equal to 30 mA with a time delay of 15 ms and to reclose the circuit again after 5 minutes.

Effects of Chemistry Parameters of Primary Water affecting Leakage of Steam Generator Tube Cracks

Energy Technology Data Exchange (ETDEWEB)

Shin, D. M.; Cho, N. C.; Kang, Y. S.; Lee, K. H. [KHNP CRI, Daejeon (Korea, Republic of)

2016-10-15

Degradation of steam generator (SG) tubes can affect pressure boundary tightness. As a defense-in-depth measure, primary to secondary leak monitoring program for steam generators is implemented, and operation is allowed under leakage limits in nuclear power plants. Chemistry parameters that affect steam generator tube leakage due to primary water stress corrosion cracking (PWSCC) are investigated in this study. Tube sleeves were installed to inhibit leakage and improve tube integrity as a part of maintenance methods. Steam generators occurred small leak during operation have been replaced with new steam generators according to plant maintenance strategies. The correlations between steam generator leakage and chemistry parameters are presented. Effects of primary water chemistry parameters on leakage from tube cracks were investigated for the steam generators experiencing small leak. Unit A experienced small leakage from steam generator tubes in the end of operation cycle. It was concluded that increased solubility of oxides due to high pHT could make leakage paths, and low boron concentration lead to less blockage in cracks. Increased dissolved hydrogen may retard crack propagations, but it did not reduce leak rate of the leaking steam generator. In order to inhibit and reduce leakage, pH{sub T} was controlled by servicing cation bed operation. The test results of decreasing pHT indicate low pHT can reduce leak rate of PWSCC cracks in the end of cycle.

Effects of Chemistry Parameters of Primary Water affecting Leakage of Steam Generator Tube Cracks

International Nuclear Information System (INIS)

Shin, D. M.; Cho, N. C.; Kang, Y. S.; Lee, K. H.

2016-01-01

Degradation of steam generator (SG) tubes can affect pressure boundary tightness. As a defense-in-depth measure, primary to secondary leak monitoring program for steam generators is implemented, and operation is allowed under leakage limits in nuclear power plants. Chemistry parameters that affect steam generator tube leakage due to primary water stress corrosion cracking (PWSCC) are investigated in this study. Tube sleeves were installed to inhibit leakage and improve tube integrity as a part of maintenance methods. Steam generators occurred small leak during operation have been replaced with new steam generators according to plant maintenance strategies. The correlations between steam generator leakage and chemistry parameters are presented. Effects of primary water chemistry parameters on leakage from tube cracks were investigated for the steam generators experiencing small leak. Unit A experienced small leakage from steam generator tubes in the end of operation cycle. It was concluded that increased solubility of oxides due to high pHT could make leakage paths, and low boron concentration lead to less blockage in cracks. Increased dissolved hydrogen may retard crack propagations, but it did not reduce leak rate of the leaking steam generator. In order to inhibit and reduce leakage, pH_T was controlled by servicing cation bed operation. The test results of decreasing pHT indicate low pHT can reduce leak rate of PWSCC cracks in the end of cycle

Theoretical investigation of metal magnetic memory testing technique for detection of magnetic flux leakage signals from buried defect

Science.gov (United States)

Xu, Kunshan; Qiu, Xingqi; Tian, Xiaoshuai

2018-01-01

The metal magnetic memory testing (MMMT) technique has been extensively applied in various fields because of its unique advantages of easy operation, low cost and high efficiency. However, very limited theoretical research has been conducted on application of MMMT to buried defects. To promote study in this area, the equivalent magnetic charge method is employed to establish a self-magnetic flux leakage (SMFL) model of a buried defect. Theoretical results based on the established model successfully capture basic characteristics of the SMFL signals of buried defects, as confirmed via experiment. In particular, the newly developed model can calculate the buried depth of a defect based on the SMFL signals obtained via testing. The results show that the new model can successfully assess the characteristics of buried defects, which is valuable in the application of MMMT in non-destructive testing.

Sargent and Lundy containment tests revisited

International Nuclear Information System (INIS)

Henry, Robert E.; Hammersley, Robert J.

2005-01-01

The pressurization experiments performed in the intermediate scale Sargent and Lundy containment test facility provide numerous insights into the dominant heat and mass transfer processes under design basis accident conditions similar to a large break Loss of Coolant Accident (LOCA). These experiments were the first integral tests to examine the containment response to a dynamic blowdown from the Reactor Coolant System (RCS). Measurements included the blowdown rate of the simulated Reactor Pressure Vessel (RPV), the pressure in containment as well as the containment temperatures in the top and bottom of the containment vessel. Furthermore, various experiments were performed with the blowdown location changed from the vessel bottom to the lower third of the vessel, the upper third of the vessel and near the top of the RPV to examine the influence of different types of break elevations, i.e. different characterizations of the exhausting steam-water mixture. Perhaps the most insightful set of measurements from these experiments were those that varied the cold water mass initially resident in the bottom of the simulated containment vessel. The role of this water as a function of its initial mass and the break location showed substantial influence of this water if the blowdown location provided sufficient energy to disperse this cold water into the containment building atmosphere. This is demonstrated in Figure 1 taken from Kolflat, 1960. All of these are relevant to an understanding of the dominant physical processes for this type of postulated accident condition. As such, it is important that all of these insights are retained and used in models for the containment building thermal-hydraulic response under accident conditions. Reference: Kolflat, A., 1960, 'Resulting of 1959 Nuclear Power Plant Containment Test', Sargent and Lundy Report SL-1800; Kolflat, A. and Chittenden, W. A., 1957, 'A New Approach to the Design of Containment Shells for Atomic Power Plants

Probabilistic evaluation of concrete containment capacity for beyond design basis internal pressures

International Nuclear Information System (INIS)

Tang, H.T.; Dameron, R.A.; Rashid, Y.R.

1995-01-01

For beyond design basis internal pressure loading, experimental studies have demonstrated that the most probable failure mode governing the ultimate functional capacity of concrete containments is leak rather than break. Based on leak rates measured in experiments, a prediction formula for leak rate as functions of containment liner size and internal pressure has been postulated. The determination of liner tear is cast in a probabilistic framework. In calculating leakage, particular attention is paid to the evaluation of leakage versus rupture and the loading rates that may be required to leapfrog over a leakage mode. (orig.)

Tension tests of concrete containment wall elements

International Nuclear Information System (INIS)

Schultz, D.M.; Julien, J.T.; Russel, H.G.

1984-01-01

Tension tests of concrete containment wall elements were conducted as part of a three-phase research program sponsored by the Electric Power Research Institute (EPRI). The objective of the EPRI experimental/analytical program is twofold. The first objective is to provide the utility industry with a test-verified analytical method for making realistic estimates of actual capacities of reinforced and prestressed concrete containments under internal over-pressurization from postulated degraded core accidents. The second objective is to determine qualitative and quantitative leak rate characteristics of typical containment cross-sections with and without penetrations. This paper covers the experimental portion to the EPRI program. The testing program for Phase 1 included eight large-scale specimens representing elements from the wall of a containment. Each specimen was 60-in (1525-mm) square, 24-in (610-mm) thick, and had full-size reinforcing bars. Six specimens were representative of prototypical reinforced concrete containment designs. The remaining two specimens represented prototypical prestressed containment designs. Various reinforcement configurations and loading arrangements resulted in data that permit comparisons of the effects of controlled variables on cracking and subsequent concrete/reinforcement/liner interaction in containment elements. Subtle differences, due to variations in reinforcement patterns and load applications among the eight specimens, are being used to benchmark the codes being developed in the analytical portion of the EPRI program. Phases 2 and 3 of the test program will examine leak rate characteristics and failure mechanisms at penetrations and structural discontinuities. (orig.)

Prevalence of extravertebral cement leakage after vertebroplasty: procedural documentation versus CT detection.

Science.gov (United States)

Martin, Douglas J; Rad, Arash Ehteshami; Kallmes, David F

2012-06-01

Reported incidence of extravertebral cement leakage after vertebroplasty varies widely across studies. To retrospectively compare the relative detection rates of extravertebral leakage noted under intra-procedural fluoroscopic surveillance, postprocedure plain radiographs, and postprocedure computed tomography (CT) in a cohort of patients undergoing vertebroplasty. With IRB approval, we retrospectively identified 181 patients with 277 levels treated with percutaneous vertebroplasty among a total of 1255 patients undergoing vertebroplasty between 1999 and 2010 who had subsequently undergone a CT examination that included the treated level(s). Categories of leakage were paravertebral, end plate, epidural, and prevertebral venous leakage. CT-detected leak rates were then compared to those noted on the vertebroplasty procedure reports and the archived fluoroscopic images for this same cohort using Pearson's χ(2) test. One hundred and forty-nine (82%, 95% CI 76-87%) of 181 patients demonstrated evidence of some type of leakage on CT at one or more treated levels. Sixty-two (34%, 95% CI 28-42%) and seventy-seven (50%, 95% CI 43-57%) of 149 CT-detected leaks were reported in the procedural dictation or detected on plain radiography (P = 0.01 and 0.006, respectively). The most common type of leakage noted on CT was end plate (n = 81, 45%, 95% CI 38-52%), followed by paravertebral (n = 64, 35%, 95% CI 29-43%), epidural (n = 36, 20%, 95% CI 15-26%), and prevertebral venous (n = 32, 18%, 95% CI 13-24%). Cement leakage after vertebroplasty is common and is often not reported by operators in procedural dictations. CT detects substantially more leaks than plain radiography.

Alopecia associated with unexpected leakage from electron cone

Energy Technology Data Exchange (ETDEWEB)

Wen, B.C.; Pennington, E.C.; Hussey, D.H.; Jani, S.K.

1989-06-01

Excessive irradiation due to unexpected leakage was found on a patient receiving electron beam therapy. The cause of this leakage was analyzed and the amount of leakage was measured for different electron beam energies. The highest leakage occurred with a 6 x 6 cm cone using a 12 MeV electron beam. The leakage dose measured along the side of the cone could be as great as 40%. Until the cones are modified or redesigned, it is advised that all patient setups be carefully reviewed to assure that no significant patient areas are in the side scatter region.

Confirmation tests of PWR surveillance capsule shipping container

International Nuclear Information System (INIS)

Tomita, N.; Ue, K.; Ohashi, M.; Asada, K.; Yoneda, Y.

1980-01-01

Mitsubishi Heavy Industries, Ltd. carried out the confirmation tests to confirm the reliability of the PWR surveillance capsule shipping container and to collect cask design data using a 10-ton weight full scale model at Kobe Shipyard and Engine Works. This report presents the outline of these tests. The B Type container was a cylinder 3289 mm long, 1080 mm in diameter and designed in accordance with the new modified Japanese regulations similar to IAEA regulation. These tests consist of four 9 m drop tests, two 1 m puncture tests, a fire test and an immersion test. In conclusion, safetyness of this container has been proved and various technical data for cask design were also collected through these tests. (author)

Leakage Detection and Estimation Algorithm for Loss Reduction in Water Piping Networks

Directory of Open Access Journals (Sweden)

Kazeem B. Adedeji

2017-10-01

Full Text Available Water loss through leaking pipes constitutes a major challenge to the operational service of water utilities. In recent years, increasing concern about the financial loss and environmental pollution caused by leaking pipes has been driving the development of efficient algorithms for detecting leakage in water piping networks. Water distribution networks (WDNs are disperse in nature with numerous number of nodes and branches. Consequently, identifying the segment(s of the network and the exact leaking pipelines connected to this segment(s where higher background leakage outflow occurs is a challenging task. Background leakage concerns the outflow from small cracks or deteriorated joints. In addition, because they are diffuse flow, they are not characterised by quick pressure drop and are not detectable by measuring instruments. Consequently, they go unreported for a long period of time posing a threat to water loss volume. Most of the existing research focuses on the detection and localisation of burst type leakages which are characterised by a sudden pressure drop. In this work, an algorithm for detecting and estimating background leakage in water distribution networks is presented. The algorithm integrates a leakage model into a classical WDN hydraulic model for solving the network leakage flows. The applicability of the developed algorithm is demonstrated on two different water networks. The results of the tested networks are discussed and the solutions obtained show the benefits of the proposed algorithm. A noteworthy evidence is that the algorithm permits the detection of critical segments or pipes of the network experiencing higher leakage outflow and indicates the probable pipes of the network where pressure control can be performed. However, the possible position of pressure control elements along such critical pipes will be addressed in future work.

Radiation induced leakage current and stress induced leakage current in ultra-thin gate oxides

International Nuclear Information System (INIS)

Ceschia, M.; Paccagnella, A.; Cester, A.; Scarpa, A.

1998-01-01

Low-field leakage current has been measured in thin oxides after exposure to ionizing radiation. This Radiation Induced Leakage Current (RILC) can be described as an inelastic tunneling process mediated by neutral traps in the oxide, with an energy loss of about 1 eV. The neutral trap distribution is influenced by the oxide field applied during irradiation, thus indicating that the precursors of the neutral defects are charged, likely being defects associated to trapped holes. The maximum leakage current is found under zero-field condition during irradiation, and it rapidly decreases as the field is enhanced, due to a displacement of the defect distribution across the oxide towards the cathodic interface. The RILC kinetics are linear with the cumulative dose, in contrast with the power law found on electrically stressed devices

Differences in Ostomy Pouch Seal Leakage Occurrences Between North American and European Residents.

Science.gov (United States)

Fellows, Jane; Forest Lalande, Louise; Martins, Lina; Steen, Anne; Størling, Zenia M

The purpose of this study was to compare experiences and concerns about pouch seal leakage between persons with ostomies residing in North America (Canada and the United States) and Europe (United Kingdom, Netherlands, Sweden, Germany, Belgium, France, and Italy). Differences in reported pouch wear time and accessories used between the 2 groups were also examined. Secondary analysis of data from a cross-sectional study (Ostomy Life Study). Responses from persons residing in European countries (n = 1939) were compared with responses of 1387 individuals residing in North American countries. Persons with an ostomy completed a questionnaire that focused on 4 topics related to the daily use of an ostomy pouching system (pouch seal leakage, ballooning, appearance of pouching system such as color and size of the pouch and whether it is discrete under clothing, and coupling failure of 2-piece pouching systems). Pouch seal leakage was defined as stomal effluent seeping between the skin and the wafer of the ostomy pouching system. Statistical analysis was performed using a proportional odds model including various variable effects. Special attention was given to frequency of pouch seal leakage occurrences. All tests were 2-sided; P values ≤.05 were deemed statistically significant. Participants living in the North American countries indicated they were more likely to experience leakage from the ostomy (odds ratio = 2.610, 95% CI 2.187-3.115; P < .0001). Findings also indicated they were more likely to worry about pouch seal leakage than those in the European countries' data set (odds ratio = 2.722, 95% CI 2.283-3.246; P < .0001). Participants residing in the North American countries had significantly longer wear times than those participants in the European countries (P < .0001, χ test). The use of accessories was associated with a longer pouching system wear time. Study results suggest that participants from the North American countries indicated significantly more

Monitoring underground water leakage pattern by ground penetrating radar (GPR) using 800 MHz antenna frequency

Science.gov (United States)

Amran, T. S. T.; Ismail, M. P.; Ahmad, M. R.; Amin, M. S. M.; Ismail, M. A.; Sani, S.; Masenwat, N. A.; Basri, N. S. M.

2018-01-01

Water is the most treasure natural resources, however, a huge amount of water are lost during its distribution that leads to water leakage problem. The leaks meant the waste of money and created more economic loss to treat and fix the damaged pipe. Researchers and engineers have put tremendous attempts and effort, to solve the water leakage problem especially in water leakage of buried pipeline. An advanced technology of ground penetrating radar (GPR) has been established as one of the non-destructive testing (NDT) method to detect the underground water pipe leaking. This paper focuses on the ability of GPR in water utility field especially on detection of water leaks in the underground pipeline distribution. A series of laboratory experiments were carried out using 800-MHz antenna, where the performance of GPR on detecting underground pipeline and locating water leakage was investigated and validated. A prototype to recreate water-leaking system was constructed using a 4-inch PVC pipe. Different diameter of holes, i.e. ¼ inch, ½ inch, and ¾ inch, were drilled into the pipe to simulate the water leaking. The PVC pipe was buried at the depth of 60 cm into the test bed that was filled with dry sand. 15 litres of water was injected into the PVC pipe. The water leakage patterns in term of radargram data were gathered. The effectiveness of the GPR in locating the underground water leakage was ascertained, after the results were collected and verified.

Risk of acute anastomotic leakage after preoperative radiotherapy in rectal cancer

Directory of Open Access Journals (Sweden)

Devid Belalla

2016-11-01

Full Text Available Objective: To evaluate the preoperative radiotherapy and its role in anastomotic leakage. Methods: A total of 327 patients who had an anterior resection (AR in elective surgery for a rectal carcinoma were selected and operated in our clinic of surgery during the period from 2003 to 2015. Among them, 135 patients had a low anterior resection (LAR and the other 192 had an AR. This is a retrospective study. Chi-squared test was used to evaluate statistical differences and the P < 0.05 was considered statistically significant. Results: A total of 126 patients had radiotherapy before surgery, and 50 of them had a LAR. In the other 201 patients, surgery was the first treatment modality, and 83 of them had a LAR. We had an overall anastomotic leakage of 7.95% or 26% patients. Anastomotic leakage was found in 14 patients with LAR, 9 of which had radiotherapy before surgery. From the 12 patients with AR who had an anastomotic leakage, 6 of them had radiotherapy before surgery. Conclusions: Radiotherapy may affect anastomotic healing and increase the risk of leakage. This risk is higher in low anterior anastomoses where a protective stoma may be considered. A better evaluation and support for patients with preoperative radiotherapy is needed in order to diminish the concomitant risk factors as much as possible.

Leakage Resilient Secure Two-Party Computation

DEFF Research Database (Denmark)

Damgård, Ivan Bjerre; Hazay, Carmit; Patra, Arpita

2012-01-01

we initiate the study of {\\em secure two-party computation in the presence of leakage}, where on top of corrupting one of the parties the adversary obtains leakage from the content of the secret memory of the honest party. Our study involves the following contributions: \\BE \\item {\\em Security...... and returns its result. Almost independently of secure computation, the area of {\\em leakage resilient cryptography} has recently been evolving intensively, studying the question of designing cryptographic primitives that remain secure even when some information about the secret key is leaked. In this paper...

Why the CDM can reduce carbon leakage

International Nuclear Information System (INIS)

Kallbekken, S.

2006-04-01

Carbon leakage is an important concern because it can reduce the environmental effectiveness of the Kyoto Protocol. The Clean Development Mechanism, one of the flexibility mechanisms allowed under the protocol, has the potential to reduce carbon leakage significantly because it reduces the relative competitive disadvantage to Annex B countries of restricting greenhouse gas emissions. The economic intuition behind this mechanism is explored in a theoretical analysis. It is then analyzed numerically using a CGE model. The results indicate that, assuming appropriate accounting for leakage and under realistic assumptions on CDM activity, the CDM has the potential to reduce the magnitude of carbon leakage by around three fifths

Particle and radiation leakage importance: definition, analysis, and interpretation

International Nuclear Information System (INIS)

Cacuci, D.G.; Wagschal, J.J.; Yaari, A.

1982-01-01

The concept of leakage importance function has been introduced and analyzed for physical systems governed by the Boltzmann transport equation. This leakage importance function represents a measure of the relative importance of source particles located at every point in phase space in contributing to the leakage and provides insight regarding the specific physical process that leads to leakage. The equation satisfied by the leakage importance function has been derived by using adjoint operators. It has been shown that procedures that are customarily used to derive an equation obeyed by an importance function suitable for an integral parameter such as a detector response or an eigenvalue lead to difficulties when directly applied to derive an equation obeyed by the leakage importance function. This is because, although leakage is also an integral parameter (i.e., a functional of the forward flux density), leakage is expressed in terms of a surface integral rather than in terms of volume integrals such as those appearing in expressions of detector responses or eigenvalues. Therefore, a procedure that departs from the customary course has been devised to derive the equation satisfied by the leakage importance function

[Nursing Experience With a Patient With Gastrostomy Leakage Resulting in Moisture-Associated Skin Damage].

Science.gov (United States)

Hsu, Mei-Yu; Hsu, Hsiao-Hui; Lyu, Ji-Yan

2016-10-01

Leakage is a common complication of gastrostomy. Exposure of the skin surrounding the gastrostomy tube to moisture or chemical irritants may cause moisture-associated skin damage (MASD) and seriously affect the patient's quality of life. This case study describes a nursing experience with gastrostomy leakage that resulted in MASD. An assessment conducted from July 29, 2015 to August 20, 2015 revealed that heavy gastronomy leakage had caused extensive skin erosion, ulceration, hyperplasia, and superficial infection. Simultaneously, the patient was required to conduct complex stoma care, which resulted in physical and psychological exhaustion. Changes in traditional tube and wound care were discussed on multiple occasions with an interdisciplinary healthcare team. Based on the evidence-based literature, we provide gastrostomy and MASD management strategies. Through team collaboration, we prevented gastric contents from contacting the patient's skin directly, improved patient comfort, controlled effluent and skin infections, maintained fluid and electrolyte balances, and acce-lerated the healing of the damaged skin. We recommend that healthcare professionals caring for patients with gastrostomy leakage be provided with early skin protection programs to learn the standard methods for identifying and correcting leakage factors, containing effluent, and adequately stabilizing the gastrostomy tube in order to reduce the impact on the patient's quality of life. In addition, patient education on tube and skin care should be provided to prevent the reoccurrence of complications.

Full-scale testing of leakage of blast waves inside a partially vented room exposed to external air blast loading

Science.gov (United States)

Codina, R.; Ambrosini, D.

2018-03-01

For the last few decades, the effects of blast loading on structures have been studied by many researchers around the world. Explosions can be caused by events such as industrial accidents, military conflicts or terrorist attacks. Urban centers have been prone to various threats including car bombs, suicide attacks, and improvised explosive devices. Partially vented constructions subjected to external blast loading represent an important topic in protective engineering. The assessment of blast survivability inside structures and the development of design provisions with respect to internal elements require the study of the propagation and leakage of blast waves inside buildings. In this paper, full-scale tests are performed to study the effects of the leakage of blast waves inside a partially vented room that is subjected to different external blast loadings. The results obtained may be useful for proving the validity of different methods of calculation, both empirical and numerical. Moreover, the experimental results are compared with those computed using the empirical curves of the US Defense report/manual UFC 3-340. Finally, results of the dynamic response of the front masonry wall are presented in terms of accelerations and an iso-damage diagram.

75 FR 29699 - Total Inward Leakage Requirements for Respirators

Science.gov (United States)

2010-05-27

... or other half-mask respirator inward leakage measurement, and offer any additional comments on the..., facsimile (412) 386-4089, e-mail [email protected] . SUPPLEMENTARY INFORMATION: I. Background The Department of... order to conduct tests and prepare responses. On April 20, 2010, NIOSH responded by reopening the docket...

Prevalence of extravertebral cement leakage after vertebroplasty: procedural documentation versus CT detection

International Nuclear Information System (INIS)

Martin, Douglas J.; Rad, Arash Ehteshami; Kallmes, David F.

2012-01-01

Background: Reported incidence of extravertebral cement leakage after vertebroplasty varies widely across studies. Purpose: To retrospectively compare the relative detection rates of extravertebral leakage noted under intra-procedural fluoroscopic surveillance, post procedure plain radiographs, and post procedure computed tomography (CT) in a cohort of patients undergoing vertebroplasty. Material and Methods: With IRB approval, we retrospectively identified 181 patients with 277 levels treated with percutaneous vertebroplasty among a total of 1255 patients undergoing vertebroplasty between 1999 and 2010 who had subsequently undergone a CT examination that included the treated level(s). Categories of leakage were paravertebral, end plate, epidural, and pre vertebral venous leakage. CT-detected leak rates were then compared to those noted on the vertebroplasty procedure reports and the archived fluoroscopic images for this same cohort using Pearson's χ 2 test. Results: One hundred and forty-nine (82%, 95% CI 76-87%) of 181 patients demonstrated evidence of some type of leakage on CT at one or more treated levels. Sixty-two (34 %, 95 % CI 28-42 %) and seventy-seven (50%, 95% CI 43-57%) of 149 CT-detected leaks were reported in the procedural dictation or detected on plain radiography (P 0.01 and 0.006, respectively). The most common type of leakage noted on CT was end plate (n = 81, 45%, 95% CI 38-52%), followed by paravertebral (n 64, 35%, 95% CI 29-43%), epidural (n = 36, 20%, 95% CI 15-26%), and pre vertebral venous (n = 32, 18%, 95% CI 13-24%). Conclusion: Cement leakage after vertebroplasty is common and is often not reported by operators in procedural dictations. CT detects substantially more leaks than plain radiography

Containment performance working group report. Draft report for comment

International Nuclear Information System (INIS)

1985-05-01

Containment buildings for power reactors have been studied to estimate their leak rate as a function of increasing internal pressure and temperature associated with severe accident sequences involving significant core damage. Potential leak paths through containment penetration assemblies (such as equipment hatches, airlocks, purge and vent valves, and electrical penetrations) have been identified and their contributions to leak area for the containment are incorporated into containment response analyses of selected severe accident sequences to predict the containment leak rate and pressure/temperature response as a function of time. Because of lack of reliable experimental data on the leakage behavior of containment penetrations and isolation barriers at pressures beyond their design conditions, an analytical approach has been used to estimate the leakage behavior of components found in specific reference plants that approximately characterize the various containment types

Safety Test Report for the PWR S/F Dry Storage System

Energy Technology Data Exchange (ETDEWEB)

Seo, K. S.; Lee, J. H.; Koo, K. H.; Lee, J. C.; Choi, W. S.; Bang, K. S.; Park, H. Y.; Jang, S. Y

2008-10-15

This is contract report conducted by KAERI under the contract with NETEC for safety test for the PWR S/F dry storage system. Leak Test was performed after drop test and turn-over test, the measured leakage rate was lower than allowable leakage rate. It is revealed that the containment integrity of the dry storage system is maintained. In the seismic test, the moving of the model was measured at SRTH seismic response of 0.4 g and 0.8 g. Therefore the seismic test results can be used fully to the test data for verification of the seismic analysis. In the thermal test, the direction of the inlet and outlet of the air has no effect on the heat transfer performance. The passive heat removal system of the horizontal storage module was designed well.

Full scale BWR containment LOCA response test at the INKA test facility

International Nuclear Information System (INIS)

Wagner, Thomas; Leyer, Stephan

2015-01-01

KERENA is an innovative boiling water reactor concept with passive safety systems (Generation III+) of AREVA. The reactor is an evolutionary design of operating BWRs (Generation II). In order to verify the functionality and performance of the KERENA safety concept required for the transient and accident management, the test facility “Integral Teststand Karlstein” (INKA) was built at Karlstein (Germany). It is a mock-up of the KERENA boiling water reactor containment, with integrated pressure suppression system. The complete chain of passive safety components is available. The passive components and the levels are represented in full scale. The volume scaling of the containment compartments is approximately 1:24. The reactor pressure vessel (RPV) is simulated via the steam accumulator of the Karlstein Large Valve Test Facility. This vessel provides an energy storage capacity of approximately 1/6 of the KERENA RPV and is supplied by a Benson boiler with a thermal power of 22 MW. With respect to the available power supply, the containment- and system-sizing of the facility is by far the largest one of its kind worldwide. From 2009 to 2012, several single component tests were conducted (Emergency Condenser, Containment Cooling Condenser, Core Flooding System etc.). On March 21st, 2013, the worldwide first large-scale only passively managed integral accident test of a boiling water reactor was simulated at INKA. The integral test measured the combined response of the KERENA passive safety systems to the postulated initiating event was the “Main Steam Line Break” (MSLB) inside the Containment with decay heat simulation. The results of the performed integral test (MSLB) showed that the passive safety systems alone are capable to bring the plant to stable conditions meeting all required safety targets with sufficient margins. Therefore the test verified the function of those components and the interplay between them as response to an anticipated accident scenario

Design and testing of wood containers for radioactive waste

International Nuclear Information System (INIS)

Roberts, R.S.; Barry, P.E.

1981-01-01

A wood container for shipping and storing radioactive waste was designed to eliminate the problems caused by the weight, cost, and shape of the steel containers previously used. Tests specified by federal regulations (compression, free-drop, penetration, and vibration) were conducted on two of the containers, one loaded to 2500 lb and one loaded to 5000 lb. The 5000-lb container failed the free-drop test, but the 2500-lb container easily passed the tests and therefore qualifies as a Type A container. Its simplicity of design, low weight, and ease in handling have proved to be time-saving and cost-effective

Insights into the behavior of LWR steel containment buildings during severe accidents

International Nuclear Information System (INIS)

Clauss, D.B.; Horschel, D.S.; Blejwas, T.E.

1987-01-01

Investigations into the performance of steel containment subject to pressure and temperature greater than their design basis loads are discussed. The timing, mechanism, and location of a containment failure, i.e., release of radioactive materials, have an important impact on the consequences of a severe accident. We review the results of experiments on steel containment models pressurized to failure, on aged and unaged seals subjected to elevated temperature and pressure, and on electrical penetration assemblies tested for leakage. Based on the results, the important features and details of analytical methods that can be used to predict containment performance are identified. Finally, we speculate on the performance of steel containments in severe accident conditions. (orig.)

Leak before break behaviour of austenitic and ferritic pipes containing circumferential defects

Energy Technology Data Exchange (ETDEWEB)

Stadtmueller, W.; Sturm, D.

1997-04-01

Several research projects carried out at MPA Stuttgart to investigate the Leak-before-Break (LBB) behavior of safety relevant pressure bearing components are summarized. Results presented relate to pipes containing circumferential defects subjected to internal pressure and external bending loading. An overview of the experimentally determined results for ferritic components is presented. For components containing postulated or actual defects, the dependence of the critical loading limit on the defect size is shown in the form of LBB curves. These are determined experimentally and/or by calculation for through-wall slits, and represent the boundary curve between leakage and massive fracture. For surface defects and a given bending moment and internal pressure, no fracture will occur if the length at leakage remains smaller than the critical defect length given by the LBB curve for through-wall defects. The predictive capability of engineering calculational methods are presented by way of example. The investigation programs currently underway, testing techniques, and initial results are outlined.

Proof testing of CANDU concrete containment structures

International Nuclear Information System (INIS)

Pandey, M.D.

1996-05-01

Prior to commissioning of a CANDU reactor, a proof pressure test is required to demonstrate the structural integrity of the containment envelope. The test pressure specified by AECB Regulatory Document R-7 (1991) was selected without a rigorous consideration of uncertainties associated with estimates of accident pressure and conatinment resistance. This study was undertaken to develop a reliability-based philosophy for defining proof testing requirements that are consistent with the current limit states design code for concrete containments (CSA N287.3).It was shown that the upodated probability of failure after a successful test is always less than the original estimate

International Market Leakage from China’s Forestry Policies

Directory of Open Access Journals (Sweden)

Xin Hu

2014-11-01

Full Text Available Carbon leakage can be a problem when seeking to reduce carbon emissions through forest policy. International market leakage is mainly caused by supply and demand imbalances in the timber market. This paper selects China, which is implementing forestry policy changes, as the research object. We begin by offering a brief analysis of China’s forestry policy changes, such as the logging quota and Six Key Forestry Programs to determine whether those policies affect timber supply. Second, through the use of three shock variables, carbon leakage is simulated under different scenarios by the Global Trade Analysis Project (GTAP model. The results reveal that the magnitude of leakage caused by implementing China’s forestry policies is between 79.7% and 88.8% with carbon leakage mainly displaced to Russia, Southeast Asia, and the EU. Two effective scenarios for reducing market leakage are presented: forest tenure reform and fast growing forest projects to improve domestic timber production, and raising tariffs on timber imports to reduce imports.

Proving Test on the Reliability for Reactor Containment Vessel

International Nuclear Information System (INIS)

Takumi, K.; Nonaka, A.

1988-01-01

NUPEC (Nuclear Power Engineering Test Center) has started an eight-year project of Proving Test on the Reliability for Reactor Containment Vessel since June 1987. The objective of this project is to confirm the integrity of containment vessels under severe accident conditions. This paper shows the outline of this project. The test Items are (1) Hydrogen mixing and distribution test, (2) Hydrogen burning test, (3) Iodine trapping characteristics test, and (4) Structural behavior test. Based on the test results, computer codes are verified and as the results of analysis and evaluation by the computer codes, containment integrity is to be confirmed

Concrete containment integrity software: Procedure manual and guidelines

International Nuclear Information System (INIS)

Dameron, R.A.; Dunham, R.S.; Rashid, Y.R.

1990-06-01

This report is an executive summary describing the concrete containment analysis methodology and software that was developed in the EPRI-sponsored research to predict the overpressure behavior and leakage of concrete containments. A set of guidelines has been developed for performing reliable 2D axisymmetric concrete containment analysis with a cracking concrete constitutive model developed by ANATECH. The software package developed during this research phase is designed for use in conjunction with ABAQUS-EPGEN; it provides the concrete model and automates axisymmetric grid preparation, and rebar generation for 2D and 3D grids. The software offers the option of generating pre-programmed axisymmetric grids that can be tailored to a specific containment by input of a few geometry parameters. The goal of simplified axisymmetric analysis within the framework of the containment leakage prediction methodology is to compute global liner strain histories at various locations within the containment. A simplified approach for generating peak liner strains at structural discontinuities as function of the global liner strains has been presented in a separate leakage criteria document; the curves for strain magnification factors and liner stress triaxiality factors found in that document are intended to be applied to the global liner strain histories developed through global 2D analysis. This report summarizes the procedures for global 2D analysis and gives an overview of the constitutive model and the special purpose concrete containment analysis software developed in this research phase. 8 refs., 10 figs

Seismic proving test of PWR reactor containment vessel

International Nuclear Information System (INIS)

Akiyama, H.; Yoshikawa, T.; Tokumaru, Y.

1987-01-01

The seismic reliability proving tests of nuclear power plant facilities are carried out by Nuclear Power Engineering Test Center (NUPEC), using the large-scale, high-performance vibration of Tadotsu Engineering Laboratory, and sponsored by the Ministry of International Trade and Industry (MITI). In 1982, the seismic reliability proving test of PWR containment vessel started using the test component of reduced scale 1/3.7 and the test component proved to have structural soundness against earthquakes. Subsequently, the detailed analysis and evaluation of these test results were carried out, and the analysis methods for evaluating strength against earthquakes were established. Whereupon, the seismic analysis and evaluation on the actual containment vessel were performed by these analysis methods, and the safety and reliability of the PWR reactor containment vessel were confirmed

Leakage-resilient cryptography from minimal assumptions

DEFF Research Database (Denmark)

Hazay, Carmit; López-Alt, Adriana; Wee, Hoeteck

2013-01-01

We present new constructions of leakage-resilient cryptosystems, which remain provably secure even if the attacker learns some arbitrary partial information about their internal secret key. For any polynomial ℓ, we can instantiate these schemes so as to tolerate up to ℓ bits of leakage. While the...

GOTHIC MODEL OF BWR SECONDARY CONTAINMENT DRAWDOWN ANALYSES

International Nuclear Information System (INIS)

Hansen, P.N.

2004-01-01

This article introduces a GOTHIC version 7.1 model of the Secondary Containment Reactor Building Post LOCA drawdown analysis for a BWR. GOTHIC is an EPRI sponsored thermal hydraulic code. This analysis is required by the Utility to demonstrate an ability to restore and maintain the Secondary Containment Reactor Building negative pressure condition. The technical and regulatory issues associated with this modeling are presented. The analysis includes the affect of wind, elevation and thermal impacts on pressure conditions. The model includes a multiple volume representation which includes the spent fuel pool. In addition, heat sources and sinks are modeled as one dimensional heat conductors. The leakage into the building is modeled to include both laminar as well as turbulent behavior as established by actual plant test data. The GOTHIC code provides components to model heat exchangers used to provide fuel pool cooling as well as area cooling via air coolers. The results of the evaluation are used to demonstrate the time that the Reactor Building is at a pressure that exceeds external conditions. This time period is established with the GOTHIC model based on the worst case pressure conditions on the building. For this time period the Utility must assume the primary containment leakage goes directly to the environment. Once the building pressure is restored below outside conditions the release to the environment can be credited as a filtered release

Procedure to carry out leakage test in beta radiation sealed sources emitters of {sup 90}Sr/{sup 90}Y; Procedimiento para realizar prueba de fuga en fuentes selladas de radiacion beta emisoras de {sup 90}Sr/{sup 90}Y

Energy Technology Data Exchange (ETDEWEB)

Alvarez R, J. T., E-mail: trinidad.alvarez@inin.gob.m [ININ, Departamento de Metrologia de Radiaciones Ionizantes, Laboratorio Secundario de Calibracion Dosimetrica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2010-09-15

In the alpha-beta room of the Secondary Laboratory of Dosimetric Calibration of the Metrology Department of Ionizing Radiations ophthalmic applicators are calibrated in absorbed dose terms in water D{sub w}; these applicators, basically are emitter sealed sources of pure beta radiation of {sup 90}Sr / {sup 90}Y. Concretely, the laboratory quality system indicates to use the established procedure for the calibration of these sources, which establishes the requirement of to carry out a leakage test, before to calibrate the source. However, in the Laboratory leakage test certificates sent by specialized companies in radiological protection services have been received, in which are used gamma spectrometry equipment s for beta radiation leakage tests, since it is not reliable to detect pure beta radiation with a scintillating detector with NaI crystal, (because it could detect the braking radiation produced in the detector). Therefore the Laboratory has had to verify the results of the tests with a correct technique, with the purpose of determining the presence of sources with their altered integrity and radioactive material leakage. The objective of this work is to describe a technique for beta activity measurement - of the standard ISO 7503, part 1 (1988) - and its application with a detector Gm plane (type pankage) in the realization of leakage tests in emitter sources of pure beta radiation, inside the mark of quality assurance indicated by the report ICRU 76. (Author)

Determination of Unidentified Leakage Using a Kalman Smoother

International Nuclear Information System (INIS)

Jang, Soek Bo; Heo, Gyunyoung; Ra, Insik; Han, Jeonghyun; Lee, Seon Woo

2008-01-01

Since the safety significance of leaks from the RCS can widely vary depending on the source of the leak as well as the leak rate, the detection of the leakage is an important issue. The leakage is classified into 1) identified leakage which is defined as leakage into closed systems such as pump seal or valve packing leaks that can be captured, and 2) unidentified leakage which is all other leakage. The unidentified leakage is typically determined by the RCS inventory balance method which is based on NUREG-1107. Since the accuracy of leak rate calculation is dependent of the plant operating condition, the change in the RCS temperature, inventory, and the transient operating condition should be avoided during the measurement period. Nevertheless, the operation of the makeup of the borated water into the RCS and the diversion of the inventory to the outside of the RCS boundary makes it difficult to maintain the plant stable over an hour. Due to the large fluctuation of the calculated leak rate, it is sometimes hard to know the trend of the leakage as well as the instantaneous leak rate. Any fluctuation of operating conditions can results in unreliable leak rate. This study proposes a new way of determining the unidentified leak rate using a Kalman filter and smoother technique. The proposed algorithm enhances the accuracy of the leak rate calculation not only for the steady state operations but also for transients in a well timed manner

Potential errors and misuse of statistics in studies on leakage in endodontics.

Science.gov (United States)

Lucena, C; Lopez, J M; Pulgar, R; Abalos, C; Valderrama, M J

2013-04-01

To assess the quality of the statistical methodology used in studies of leakage in Endodontics, and to compare the results found using appropriate versus inappropriate inferential statistical methods. The search strategy used the descriptors 'root filling' 'microleakage', 'dye penetration', 'dye leakage', 'polymicrobial leakage' and 'fluid filtration' for the time interval 2001-2010 in journals within the categories 'Dentistry, Oral Surgery and Medicine' and 'Materials Science, Biomaterials' of the Journal Citation Report. All retrieved articles were reviewed to find potential pitfalls in statistical methodology that may be encountered during study design, data management or data analysis. The database included 209 papers. In all the studies reviewed, the statistical methods used were appropriate for the category attributed to the outcome variable, but in 41% of the cases, the chi-square test or parametric methods were inappropriately selected subsequently. In 2% of the papers, no statistical test was used. In 99% of cases, a statistically 'significant' or 'not significant' effect was reported as a main finding, whilst only 1% also presented an estimation of the magnitude of the effect. When the appropriate statistical methods were applied in the studies with originally inappropriate data analysis, the conclusions changed in 19% of the cases. Statistical deficiencies in leakage studies may affect their results and interpretation and might be one of the reasons for the poor agreement amongst the reported findings. Therefore, more effort should be made to standardize statistical methodology. © 2012 International Endodontic Journal.

The COLIMA experiment on aerosol retention in containment leak paths under severe nuclear accidents

Energy Technology Data Exchange (ETDEWEB)

Parozzi, Flavio, E-mail: flavio.parozzi@rse-web.it [RSE, Power Generation Department, via Rubattino 54, I-20134 Milano (Italy); Caracciolo, Eduardo D.J., E-mail: eduardo.caracciolo@rse-web.it [RSE, Power Generation Department, via Rubattino 54, I-20134 Milano (Italy); Journeau, Christophe, E-mail: christophe.journeau@cea.fr [CEA Cadarache (France); Piluso, Pascal, E-mail: pascal.piluso@cea.fr [CEA Cadarache (France)

2013-08-15

Highlights: ► Experiment investigating aerosol retention within concrete containment cracks under nuclear severe accident conditions. ► Provided representative conditions of the aerosols suspended inside the containment of PWRs under a severe accident. ► Prototypical aerosol particles generated with a thermite reaction and transported through the crack sample reproducing surface characteristics, temperature, pressure drop and gas leakage. ► The results indicate the significant retention due to zig-zag path. -- Abstract: CEA and RSE managed an experimental research concerning the investigation of aerosol retention within concrete containment cracks under severe accident conditions. The main experiment was carried out in November 2008 with aerosol generated from the COLIMA facility and a sample of cracked concrete with defined geometric characteristics manufactured by RSE. The facility provided representative conditions of the aerosols suspended inside the containment of PWRs under a severe accident. Prototypical aerosol particles were generated with a thermite reaction and transported through the crack sample, where surface characteristics, temperature, pressure drop and gas leakage were properly reproduced. The paper describes the approach adopted for the preparation of the cracked concrete sample and the dimensioning of the experimental apparatus, the test procedure and the measured parameters. The preliminary results, obtained from this single test, are also discussed in the light of the present knowledge about aerosol phenomena and the theoretical analyses of particle behaviour with the crack path.

Effect of Magnetic Resonance Imaging on Micro leakage of Amalgam Restorations

International Nuclear Information System (INIS)

Sayed, A.I.

2013-01-01

Objective: To authenticate whether exposure to magnetic resonance imaging (MRI) can cause micro leakage of amalgam restorations or not. Methods: This prospective in-vitro study study was conducted at Faculty of Oral and Dental Medicine, Cairo University. Thirty-six non-carious human teeth (18 premolars and 18 molars), (26 upper and 10 lower) were gathered from the Oral Surgery Department. Standard class V cavities with all margins in the enamel were made on the buccal and lingual aspects after surface debridement .Three groups of teeth were randomly assigned, each containing 12 teeth. Three types of amalgams were used, GS-80, Rupy Cap and Trend alloy. Each type of amalgams was randomly applied to one group. Each group was divided randomly into two equal categories, one was designed to be the control group and the other was scanned by a 1.5 Tesla MRI Scanner for approximately 5 minutes. Micro leakage was assessed in each group. Three amalgam specimens were scanned using 1.5 Tesla Optima MR360 Scanner .The three specimens were sticked to the superior aspect of the medium spine phantom (one specimen per scan) to induce magnetization transfer contrast to easily visualize these in vitro dental ware containing amalgam. The three specimens were scanned using the same Susceptibility Weighted Angiography (SWAN) technique in different orthogonal orientations (Axial, Coronal and Sagittal) to assess the amalgam induced artifacts during MRI scanning. The primary outcome measure was the micro leakage caused by different types of amalgams during MRI scanning; the second outcome measure was the artifacts that may be encountered by different types of amalgams during MRI scanning .

Detection device for pipeway water leakage in building

International Nuclear Information System (INIS)

Hanawa, Jun.

1988-01-01

Purpose: To rapidly detect pipeway leakage at predetermined areas over a wide range in a building. Constitution: If flooding should occur in a power plant building and left as it is, emergency core cooling system, as well as auxiliary equipments and electrical equipments of the system are flooded to make the safety shutdown of the plant impossible. The present invention copes with such a risk. That is, an inlet flow meter and as exit flow meter are disposed to the inlet and the exit of pipeways disposed in a predetermined region in the building and a flow rate difference detector between them is disposed. In this way, pipeway leakage is detected by detecting the flow rate difference between the inlet flow rate and the exit flow rate of the pipeway in the predetermined region. According to the present invention, if a pipeway in a predetermined region is raptured to cause water leakage, the pipeway leakage can rapidly be detected depending on the flow rate difference between the inlet flow rate and the exit flow rate. Further, the water leakage over the entire the predetermined region can be detected rapidly as compared with the conventional case of detecting the leakage at a restricted portion where the leakage detector is disposed. (Kamimura, M.)

Macrophage migration inhibitory factor induces vascular leakage via autophagy

Directory of Open Access Journals (Sweden)

Hong-Ru Chen

2015-01-01

Full Text Available Vascular leakage is an important feature of acute inflammatory shock, which currently has no effective treatment. Macrophage migration inhibitory factor (MIF is a pro-inflammatory cytokine that can induce vascular leakage and plays an important role in the pathogenesis of shock. However, the mechanism of MIF-induced vascular leakage is still unclear. In this study, using recombinant MIF (rMIF, we demonstrated that MIF induced disorganization and degradation of junction proteins and increased the permeability of human endothelial cells in vitro. Western blotting analysis showed that rMIF treatment induced LC3 conversion and p62 degradation. Inhibition of autophagy with a PI3K inhibitor (3-MA, a ROS scavenger (NAC or autophagosomal-lysosomal fusion inhibitors (bafilomycin A1 and chloroquine rescued rMIF-induced vascular leakage, suggesting that autophagy mediates MIF-induced vascular leakage. The potential involvement of other signaling pathways was also studied using different inhibitors, and the results suggested that MIF-induced vascular leakage may occur through the ERK pathway. In conclusion, we showed that MIF triggered autophagic degradation of endothelial cells, resulting in vascular leakage. Inhibition of MIF-induced autophagy may provide therapeutic targets against vascular leakage in inflammatory shock.

SU-F-J-144: Scatter and Leakage Survey of An Integrated MR-Linac System

Energy Technology Data Exchange (ETDEWEB)

Wang, J; Bosco, G; Darenbourg, B; Ibbott, G [UT MD Anderson Cancer Center, Houston, TX (United States)

2016-06-15

Purpose: To assess the scatter and leakage radiation of an integrated 1.5T MRI-Linac system. Methods: A 150cc chamber (model 96020C, Inovision) was used in all the scatter and leakage measurements, after being recalibrated for MV energy by the Accredited Dosimetry Calibration Laboratory at MD Anderson. The scatter radiation was measured by placing a 25 cm stack of solid-water materials at iso-center on the patient couch to simulate patient scatter. Gantry angles were positioned at 0 degree (beam pointing downward) and 270 (beam pointing laterally). Scatter radiation was measured at selective locations inside the RF room. Beam stopper leakage was measured at the exterior panel of the gantry. The head leakage was measured at 1 meter away from the Linac head in the direction which was determined to be the area of maximum leakage by wrapped films test. All measurements were repeated with the 1.5T magnetic field turned off to study the effect of magnetic field. Results: When the magnet was on (B=1.5T), the maximum head leakage at 1 meter was 191.6mR/1000MU. The scatter radiation at 1 meter from the iso-center was 1.091R/1000MU when the radiation beam was pointing downward, 1.296R/1000MU when the beam pointed laterally. The beam stopper leakage was measured as 299.4 mR/1000MU at the exterior panel of the gantry. When magnet was off (B=0), the head leakage was measured as 198.6mR/1000MU. The scatter radiation at 1 meter was 1.153R/1000MU when beam pointed downward, 1.287R/1000MU when beam pointed laterally. The beam stopper leakage was measured as 309.4 mR/1000MU at the exterior panel of the gantry. Conclusion: The measurements indicate that the scatter and leakage radiation from the integrated MR-Linac system are in-line with the expected values. The beam stopper leakage is approximately 300 mR/1000MU. The leakage and scatter difference with the magnetic field ON and OFF was within 5%. The authors received a corporate sponsored grant from Elekta which is the vendor of

RF capacitance-voltage characterization of MOSFETs with high-leakage dielectric

NARCIS (Netherlands)

Schmitz, Jurriaan; Cubaynes, F.N; Cubaynes, F.N.; Havens, R.J.; de Kort, R.; Scholten, A.J.; Tiemeijer, L.F.

2003-01-01

We present a MOS Capacitance-Voltage measurement methodology that, contrary to present methods, is highly robust against gate leakage current densities up to 1000 A/cm/sup 2/. The methodology features specially designed RF test structures and RF measurement frequencies. It allows MOS parameter

Channel follower leakage restrictor

International Nuclear Information System (INIS)

Williamson, H.E.; Smith, B.A.

1977-01-01

An improved means is provided to control coolant leakage between the flow channel and the lower tie plate of a nuclear fuel assembly. The means includes an opening in the lower tie plate and a movable element adjacent thereto. The coolant pressure within the tie plate biases the movable means toward the inner surface of the surrounding flow channel to compensate for any movement of the flow channel away from the lower tie plate to thereby control the leakage of coolant flow from the fuel assemblies to the spaces among the fuel assemblies of the core. 9 figures

Preliminary results of steel containment vessel model test

International Nuclear Information System (INIS)

Matsumoto, T.; Komine, K.; Arai, S.

1997-01-01

A high pressure test of a mixed-scaled model (1:10 in geometry and 1:4 in shell thickness) of a steel containment vessel (SCV), representing an improved boiling water reactor (BWR) Mark II containment, was conducted on December 11-12, 1996 at Sandia National Laboratories. This paper describes the preliminary results of the high pressure test. In addition, the preliminary post-test measurement data and the preliminary comparison of test data with pretest analysis predictions are also presented

Acoustic control of sodium leakage in valve gates of NPP

International Nuclear Information System (INIS)

Trykov, E.L.; Kovtun, S.N.; Anan'ev, A.A.; Yugov, S.I.

2014-01-01

Short description of sodium bench and acoustic investigation results on leakage monitoring of valves DN10 and DN40 are given. It is shown that acoustic method can be used successfully to control the leakages of sodium valves. Leakages on both type of valves increase the acoustic signal dispersion by 2-3 orders. For each type of valve acoustic system of leakage determination allows to conduct the preliminary graduation of signal dispersion on the sodium discharge rate. It make possible not only to record the leakage presence but also to determine the sodium discharge rate through the valve during the leakage [ru

Distributed public key schemes secure against continual leakage

DEFF Research Database (Denmark)

Akavia, Adi; Goldwasser, Shafi; Hazay, Carmit

2012-01-01

-secure against continual memory leakage. Our DPKE scheme also implies a secure storage system on leaky devices, where a value s can be secretely stored on devices that continually leak information about their internal state to an external attacker. The devices go through a periodic refresh protocol......In this work we study distributed public key schemes secure against continual memory leakage. The secret key will be shared among two computing devices communicating over a public channel, and the decryption operation will be computed by a simple 2-party protocol between the devices. Similarly...... against continual memory leakage, under the Bilinear Decisional Diffie-Hellman and $2$-linear assumptions. Our schemes have the following properties: 1. Our DPKE and DIBE schemes tolerate leakage at all times, including during refresh. During refresh the tolerated leakage is a (1/2-o (1),1)-fraction...

A calculation technique to improve continuous monitoring of containment integrity

International Nuclear Information System (INIS)

Dick, J.E.

1990-01-01

The containment envelope of nuclear plants is a passive and extremely effective safety feature. World experience indicates, however, that inadvertent breaches of envelope integrity can go undetected for substantial time periods. Consequently, continuous monitoring of integrity is being closely examined by many containment designers and operators. The most promising approach is to use sensors and systems that automatically measure changes in the mass of air in containment, time integrate any known air mass flow rates across containment boundaries, and perform a mass balance to obtain the air mass leaked. As fluctuations in such measurements are typically too large to enable leakage to be calculated to the desired precision, filtering and statistical techniques must be used to filter out random and time-dependent fluctuations. Current approaches cannot easily deal with nonrandom or systematic fluctuations in the measurements, including pressure changes within the containment. As a result, sampling periods must be kept short, or data measured during periods of varying containment pressure must be discarded. The technique described allows for much longer sampling periods under conditions of fluctuating containment pressure and eliminates the invalidation of data when the containment pressure fluctuation is nonrandom. It should therefore yield a much more precise value for the containment leakage characteristic. It also promises to be able to distinguish the presence of systematic errors unrelated to systematic pressure changes and to establish whether the containment leakage characteristic is laminar or turbulent

Heterogeneous neutron-leakage model for PWR pin-by-pin calculation

International Nuclear Information System (INIS)

Li, Yunzhao; Zhang, Bin; Wu, Hongchun; Shen, Wei

2017-01-01

Highlights: •The derivation of the formula of the leakage model is introduced. This paper evaluates homogeneous and heterogeneous leakage models used in PWR pin-by-pin calculation. •The implements of homogeneous and heterogeneous leakage models used in pin-cell homogenization of the lattice calculation are studied. A consistent method of cooperation between the heterogeneous leakage model and the pin-cell homogenization theory is proposed. •Considering the computational cost, a new buckling search scheme is proposed to reach the convergence faster. The computational cost of the newly proposed neutron balance scheme is much less than the power-method scheme and the linear-interpolation scheme. -- Abstract: When assembly calculation is performed with the reflective boundary condition, a leakage model is usually required in the lattice code. The previous studies show that the homogeneous leakage model works effectively for the assembly homogenization. However, it becomes different and unsettled for the pin-cell homogenization. Thus, this paper evaluates homogeneous and heterogeneous leakage models used in pin-by-pin calculation. The implements of homogeneous and heterogeneous leakage models used in pin-cell homogenization of the lattice calculation are studied. A consistent method of cooperation between the heterogeneous leakage model and the pin-cell homogenization theory is proposed. Considering the computational cost, a new buckling search scheme is proposed to reach the convergence faster. For practical reactor-core applications, the diffusion coefficients determined by the transport cross-section or by the leakage model are compared with each other to determine which one is more accurate for the Pressurized Water Reactor pin-by-pin calculation. Numerical results have demonstrated that the heterogeneous leakage model together with the diffusion coefficient determined by the heterogeneous leakage model would have the higher accuracy. The new buckling search

Functions and requirements for Hanford single-shell tank leakage detection and monitoring

International Nuclear Information System (INIS)

Cruse, J.M.; Ohl, P.C.

1995-01-01

This document provides the initial functions and requirements for leakage detection and monitoring applicable to past and potential future leakage from the Hanford Site's 149 single-shell high-level waste tanks. This mission is a part of the overall mission of the Westinghouse Hanford Company Tank Waste Remediation System division to remediate the tank waste in a safe and acceptable manner. Systems engineering principles are being applied to this effort. This document reflects the an initial step in the systems engineering approach to decompose the mission into primary functions and requirements. The document is considered approximately 30% complete relative to the effort required to produce a final version that can be used to support demonstration and/or procurement of technologies. The functions and requirements in this document apply to detection and monitoring of below ground leaks from SST containment boundaries and the resulting soil contamination. Leakage detection and monitoring is invoked in the TWRS Program in three fourth level functions: (1) Store Waste, (2) Retrieve Waste, and (3) Disposition Excess Facilities (as identified in DOE/RL-92-60 Rev. 1, Tank Waste Remediation System Functions and Requirements)

Feasibility of Autonomous Monitoring of CO2 Leakage in Aquifers: Results From Controlled Laboratory Experiments

Science.gov (United States)

Versteeg, R.; Leger, E.; Dafflon, B.

2016-12-01

Geologic sequestration of CO2 is one of the primary proposed approaches for reducing total atmospheric CO2 concentrations. MVAA (Monitoring, Verification, Accounting and Assessment) of CO2 sequestration is an essential part of the geologic CO2 sequestration cycle. MVAA activities need to meet multiple operational, regulatory and environmental objectives, including ensuring the protection of underground sources of drinking water. Anticipated negative consequences of CO2 leakage into groundwater, besides possible brine contamination and release of gaseous CO2, include a significant increase of dissolved CO2 into shallow groundwater systems, which will decrease groundwater pH and can potentially mobilize naturally occurring trace metals and ions that are commonly absorbed to or contained in sediments. Autonomous electrical geophysical monitoring in aquifers has the potential of allowing for rapid and automated detection of CO2 leakage. However, while the feasibility of such monitoring has been demonstrated by a number of different field experiments, automated interpretation of complex electrical resistivity data requires the development of quantitative relationships between complex electrical resistivity signatures and dissolved CO2 in the aquifer resulting from leakage Under a DOE SBIR funded effort we performed multiple tank scale experiments in which we investigated complex electrical resistivity signatures associated with dissolved CO2 plumes in saturated sediments. We also investigated the feasibility of distinguishing CO2 leakage signatures from signatures associated with other processes such as salt water movement, temperature variations and other variations in chemical or physical conditions. In addition to these experiments we also numerically modeled the tank experiments. These experiments showed that (a) we can distinguish CO2 leakage signatures from other signatures, (b) CO2 leakage signatures have a consistent characteristic, (c) laboratory experiments

Leakage-Resilient Circuits without Computational Assumptions

DEFF Research Database (Denmark)

Dziembowski, Stefan; Faust, Sebastian

2012-01-01

Physical cryptographic devices inadvertently leak information through numerous side-channels. Such leakage is exploited by so-called side-channel attacks, which often allow for a complete security breache. A recent trend in cryptography is to propose formal models to incorporate leakage...... on computational assumptions, our results are purely information-theoretic. In particular, we do not make use of public key encryption, which was required in all previous works...... into the model and to construct schemes that are provably secure within them. We design a general compiler that transforms any cryptographic scheme, e.g., a block-cipher, into a functionally equivalent scheme which is resilient to any continual leakage provided that the following three requirements are satisfied...

Detecting fluid leakage of a reservoir dam based on streaming self-potential measurements

Science.gov (United States)

Song, Seo Young; Kim, Bitnarae; Nam, Myung Jin; Lim, Sung Keun

2015-04-01

Between many reservoir dams for agriculture in suburban area of South Korea, water leakage has been reported several times. The dam under consideration in this study, which is located in Gyeong-buk, in the south-east of the Korean Peninsula, was reported to have a large leakage at the right foot of downstream side of the reservoir dam. For the detection of the leakage, not only geological survey but also geophysical explorations have been made for precision safety diagnosis, since the leakage can lead to dam failure. Geophysical exploration includes both electrical-resistivity and self-potential surveys, while geological surveys water permeability test, standard penetration test, and sampling for undisturbed sample during the course of the drilling investigation. The geophysical explorations were made not only along the top of dam but also transverse the heel of dam. The leakage of water installations can change the known-heterogeneous structure of the dam body but also cause streaming spontaneous (self) potential (SP) anomaly, which can be detected by electrical resistivity and SP measurements, respectively. For the interpretation of streaming SP, we used trial-and-error method by comparing synthetic SP data with field SP data for model update. For the computation, we first invert the resistivity data to obtain the distorted resistivity structure of the dam levee then make three-dimensional electrical-resistivity modeling for the streaming potential distribution of the dam levee. Our simulation algorithm of streaming SP distribution based on the integrated finite difference scheme computes two-dimensional (2D) SP distribution based on the distribution of calculated flow velocities of fluid for a given permeability structure together with physical properties. This permeability is repeatedly updated based on error between synthetic and field SP data, until the synthetic data match the field data. Through this trial-and-error-based SP interpretation, we locate the

Sustainable management of leakage from wastewater pipelines.

Science.gov (United States)

DeSilva, D; Burn, S; Tjandraatmadja, G; Moglia, M; Davis, P; Wolf, L; Held, I; Vollertsen, J; Williams, W; Hafskjold, L

2005-01-01

Wastewater pipeline leakage is an emerging concern in Europe, especially with regards to the potential effect of leaking effluent on groundwater contamination and the effects infiltration has on the management of sewer reticulation systems. This paper describes efforts by Australia, in association with several European partners, towards the development of decision support tools to prioritize proactive rehabilitation of wastewater pipe networks to account for leakage. In the fundamental models for the decision support system, leakage is viewed as a function of pipeline system deterioration. The models rely on soil type identification across the service area to determine the aggressiveness of the pipe environment and for division of the area into zones based on pipe properties and operational conditions. By understanding the interaction between pipe materials, operating conditions, and the pipe environment in the mechanisms leading to pipe deterioration, the models allow the prediction of leakage rates in different zones across a network. The decision support system utilizes these models to predict the condition of pipes in individual zones, and to optimize the utilization of rehabilitation resources by targeting the areas with the highest leakage rates.

Ship cabin leakage alarm based on ARM SCM

Science.gov (United States)

Qu, Liyan

2018-03-01

If there is a leakage in the cabin of a sailing ship, it is a major accident that threatens the personnel and property of the ship. If we can’t take timely measures, there will be a devastating disaster. In order to judge the leakage of the cabin, it is necessary to set up a leakage alarm system, so as to achieve the purpose of detecting and alarming the leakage of the cabin, and avoid the occurrence of accidents. This paper discusses the design of ship cabin leakage alarm system based on ARM SCM. In order to ensure the stability and precision of the product, the hardware design of the alarm system is carried out, such as circuit design, software design, the programming of SCM, the software programming of upper computer, etc. It is hoped that it can be of reference value to interested readers.

Risk factors, treatment and impact on outcomes of bile leakage after hemihepatectomy.

Science.gov (United States)

Zheng, Si-Ming; Li, Hong; Li, Gen-Cong; Yu, Dan-Song; Ying, Dong-Jian; Zhang, Bin; Lu, Cai-De; Zhou, Xin-Hua

2017-07-01

Risk factors for bile leakage after hemihepatectomy are unknown. A prospectively maintained database review identified patients undergoing hemihepatectomy between 1 January 2009 and 30 September 2014. Patients were divided into B/C and non-B/C bile leakage groups. Risk factors for bile leakage were predicted and assessments of their impact on patients were made. Bile leakage occurred in 91 of the 297 patients (30.6%); 64 cases were classified as grade B bile leakage (21.5%) and three cases as grade C bile leakage (1.0%). Multivariate analysis confirmed that elevated preoperative alanine transaminase (ALT), positive bile culture during surgery, hilar bile duct plasty, bilioenteric anastomosis and laparoscopic surgery were risk factors for B/C grade bile leakage (P bile leakage (P bile leakage (P bile leakage group were higher than those in the non-B/C bile leakage group (P bile leakage group also required prolonged hospitalization (P 0.05). Patient with elevated preoperative ALT, positive bile cultures during surgery, hilar bile duct plasty, bilioenteric anastomosis and laparoscopic surgery are more likely to complicate bile leakage. We should use biliary drainage such as preoperative PTBD, ENBD or intraoperative Kehr's T-tube drainage to reduce and treat bile leakage in patients with high risk of bile leakage. © 2015 Royal Australasian College of Surgeons.

Treatment of sodium spills and leakage detection at loop-type fast reactors

Energy Technology Data Exchange (ETDEWEB)

Foerster, K; Fortmann, M; Lang, H; Moellerfeld, H [Interatom, Bergisch Gladbach (Germany)

1979-03-01

Sodium spills are of great importance in the safety analysis for sodium cooled nuclear plants. Large leakages can lead to a depletion of the heat transfer system and cause the loss of cooling of the reactor. Further the hot sodium may attack structural materials. In areas with air atmosphere large amounts of sodium can burn and cause great damages. Therefore the control of large leakages is an indispensable task in design and construction of sodium cooled reactor systems. Because of the typical arrangement of widespread long pipe systems loop type plants are subject to a gradually greater risk of damage than pool type plants. The sodium catching devices of the SNR-300 are described and their function is illustrated as an example for the treatment of large spills. Since the equipment for the control of large amounts of leaking sodium is very expensive, great efforts are made in order to save costs and to decrease safety problems. It is aimed to minimize the probability of such events to a degree that they no longer are to be considered realistic. The advantageous operating conditions and the favourable material properties support this aim. Under the well known keyword 'leak-before-rupture' criterion this task is pursued. Crack growth measurements are made at structural materials under LMFBR conditions, and leakage detecting systems are being developed. Some test results concerning this task are described. Despite the fact that there are good chances to verify the leak-before-rupture criterion it is assumed that certain hypothetical accidents occur, which are to be considered in the design of the reactor plant. The extremely improbable Bethe-Tait-accident (HCDA) is such an event. It would lead to a super spill, that means to the complete depletion of the reactor tank. For the SNR-300 plant a system is provided that is able to catch this super spill and the core melt. This core catcher must withstand the high temperatures and remove the decay heat. The purpose of this

Treatment of sodium spills and leakage detection at loop-type fast reactors

International Nuclear Information System (INIS)

Foerster, K.; Fortmann, M.; Lang, H.; Moellerfeld, H.

1979-01-01

Sodium spills are of great importance in the safety analysis for sodium cooled nuclear plants. Large leakages can lead to a depletion of the heat transfer system and cause the loss of cooling of the reactor. Further the hot sodium may attack structural materials. In areas with air atmosphere large amounts of sodium can burn and cause great damages. Therefore the control of large leakages is an indispensable task in design and construction of sodium cooled reactor systems. Because of the typical arrangement of widespread long pipe systems loop type plants are subject to a gradually greater risk of damage than pool type plants. The sodium catching devices of the SNR-300 are described and their function is illustrated as an example for the treatment of large spills. Since the equipment for the control of large amounts of leaking sodium is very expensive, great efforts are made in order to save costs and to decrease safety problems. It is aimed to minimize the probability of such events to a degree that they no longer are to be considered realistic. The advantageous operating conditions and the favourable material properties support this aim. Under the well known keyword 'leak-before-rupture' criterion this task is pursued. Crack growth measurements are made at structural materials under LMFBR conditions, and leakage detecting systems are being developed. Some test results concerning this task are described. Despite the fact that there are good chances to verify the leak-before-rupture criterion it is assumed that certain hypothetical accidents occur, which are to be considered in the design of the reactor plant. The extremely improbable Bethe-Tait-accident (HCDA) is such an event. It would lead to a super spill, that means to the complete depletion of the reactor tank. For the SNR-300 plant a system is provided that is able to catch this super spill and the core melt. This core catcher must withstand the high temperatures and remove the decay heat. The purpose of this

Leakage localization with an acoustic array that covers a wide area for pipeline leakage monitoring in a closed space

Energy Technology Data Exchange (ETDEWEB)

Park, Choon Su [Center for Safety Measurements, Division of Metrology for Quality of Life, Korea Research institute of Standards and Science, Daejeon (Korea, Republic of); Jeon, Jong Hoon [Hyundai Heavy Industry Co.,Ltd., Ulsan (Korea, Republic of); Park, Jin Ho [Korea Atomiv Energy Institute, Daejeon (Korea, Republic of)

2013-10-15

It is of great importance to localize leakages in complex pipelines for assuring their safety. A sensor array that can detect where leakages occur enables us to monitor a wide area with a relatively low cost. Beam forming is a fast and efficient algorithm to estimate where sources are, but it is generally made use of in free field condition. In practice, however, many pipelines are placed in a closed space for the purpose of safety and maintenance. This leads us to take reflected waves into account to the beam forming for interior leakage localization. Beam power distribution of reflected waves in a closed space is formulated, and spatial average is introduced to suppress the effect of reflected waves. Computer simulations and experiments ensure how the proposed method is effective to localize leakage in a closed space for structural health monitoring.

Leakage radiation spectroscopy of organic nanofibers on metal films: evidence for exciton-surface plasmon polariton interaction

DEFF Research Database (Denmark)

Jozefowski, Leszek; Fiutowski, Jacek; Bordo, Vladimir

2012-01-01

of detection. The leakage radiation was observed on the opposite side of the Ag film at the phase matching angle. The spectrally resolved intensity of the scattered radiation has been measured as a function of scattering angle at normally incident light. The spectrum contains a distinct peak at an wavelength......Leakage radiation spectroscopy of organic nanofibers composed of self-assembled organic molecules (para-Hexaphenylene, p-6P) deposited on a thin (40-60 nm) Ag film has been performed in the spectral range 420-675 nm which overlaps with the nanofiber photoluminescence band. Using a soft transfer...

A transformerless single-phase symmetrical Z-source HERIC inverter with reduced leakage currents for PV systems

DEFF Research Database (Denmark)

Li, Kerui; Shen, Yanfeng; Yang, Yongheng

2018-01-01

and thus low leakage currents in PV applications. The symmetric Z-source HERIC inverter requires two extra active switches. Nevertheless, the operation frequency of the two switches is the line frequency, leading to negligible losses. More importantly, the performance in terms of low leakage currents...... and harmonics is improved. Experimental tests are performed to validate the analysis and performance of the proposed system....

Structural and leakage integrity assessment of WWER steam generator tubes

International Nuclear Information System (INIS)

Splichal, K.; Otruba, J.; Keilova, E.; Krhounek, V.; Turek, J.

1996-01-01

The leakage and plugging limits were derived for WWER steam generators based on leak and burst tests using tubes with axial part-through and through-wall defects. The following conclusions were arrived at: (i) The permissible primary-to-secondary leak rate with respect to the permissible through-wall defect size of WWER-440 and WWER-1000 steam generator tubes is 8 l/h. (ii) The primary-to-secondary leak rate is reduced by the blocking of the tube cracks by corrosion product particles and other substances. (iii) The rate of crack penetration through the tube wall is higher than the crack widening. (iv) The validity of the criterion of instability for tubes with through-wall cracks was confirmed experimentally. For the WWER-440 and WWER-1000 steam generators, the critical size of axial through-wall cracks, for the threshold primary-to-secondary pressure difference, is 13.8 and 12.0 mm, respectively. (v) The calculated leakage for the rupture of one tube and for the assumed extreme defects is two orders and one order of magnitude, respectively, higher than the proposed primary water leakage limit of 8 l/h. (vi) The experiments gave evidence that the use of the permissible thinning limit of 80% for the heat exchange tube plugging does not bring about uncontrollable leakage or unstable crack growth. This is consistent with experience gained at WWER-440 type nuclear power plants. 4 tabs., 5 figs., 9 refs

Correlation among ESDD, NSDD and leakage current in distribution insulators

International Nuclear Information System (INIS)

Montoya, G.; Ramirez, I.; Montoya, J.I.

2004-01-01

The maintenance of distribution networks is more effective if the insulation contamination levels are known. The selection of measuring methods of pollution levels is then crucial. The relationship between several evaluation methods of pollution levels and the operating behaviour of several insulator profiles in a polluted zone is described. Laboratory tests were carried out to reproduce pollution levels found in the field. The quantity of non-soluble materials deposited over the insulators' surface affect the magnitude of the leakage current generated over a contaminated insulator. The relationship that defines leakage current with respect to the equivalent salt deposit density (ESDD) level for a specific non-soluble material level is almost linear, from which it is possible to develop a relationship between them for each insulator. (author)

Leakage Currents in Low-Voltage PME and BME Ceramic Capacitors

Science.gov (United States)

Teverovsky, Alexander

2015-01-01

Introduction of BME capacitors to high-reliability electronics as a replacement for PME capacitors requires better understanding of changes in performance and reliability of MLCCs to set justified screening and qualification requirements. In this work, absorption and leakage currents in various lots of commercial and military grade X7R MLCCs rated to 100V and less have been measured to reveal difference in behavior of PME and BME capacitors in a wide range of voltages and temperatures. Degradation of leakage currents and failures in virgin capacitors and capacitors with introduced cracks has been studied at different voltages and temperatures during step stress highly accelerated life testing. Mechanisms of charge absorption, conduction and degradation have been discussed and a failure model in capacitors with defects suggested.

Gas-path leakage seal for a gas turbine

Science.gov (United States)

Wolfe, C.E.; Dinc, O.S.; Bagepalli, B.S.; Correia, V.H.; Aksit, M.F.

1996-04-23

A gas-path leakage seal is described for generally sealing a gas-path leakage-gap between spaced-apart first and second members of a gas turbine (such as combustor casing segments). The seal includes a generally imperforate foil-layer assemblage which is generally impervious to gas and is located in the leakage-gap. The seal also includes a cloth-layer assemblage generally enclosingly contacting the foil-layer assemblage. In one seal, the first edge of the foil-layer assemblage is left exposed, and the foil-layer assemblage resiliently contacts the first member near the first edge to reduce leakage in the ``plane`` of the cloth-layer assemblage under conditions which include differential thermal growth of the two members. In another seal, such leakage is reduced by having a first weld-bead which permeates the cloth-layer assemblage, is attached to the metal-foil-layer assemblage near the first edge, and unattachedly contacts the first member. 4 figs.

Use of Anal Acoustic Reflectometry in the Evaluation of Men With Passive Fecal Leakage

DEFF Research Database (Denmark)

Hornung, Benjamin R; Telford, Karen J; Carlson, Gordon L

2017-01-01

with greater sensitivity and discriminatory ability than conventional anal manometry. OBJECTIVE: The aim of this study was to determine whether men with fecal leakage have an abnormality in anal sphincter function that is detectable by anal acoustic reflectometry. DESIGN: This was an age-matched study......BACKGROUND: Men with passive fecal leakage represent a distinct clinical entity in which the pathophysiology remains unclear. Standard anorectal investigations fail to demonstrate consistent abnormalities in this group. Anal acoustic reflectometry is a new test of anal sphincter function...... of continent and incontinent men. SETTINGS: The study was conducted at a university teaching hospital. PATIENTS: Male patients with isolated symptoms of fecal leakage were recruited. Anal acoustic reflectometry, followed by conventional anal manometry, was performed. Results were then compared with those from...

Apparatus for detecting leakage of liquid sodium

Science.gov (United States)

Himeno, Yoshiaki

1978-01-01

An apparatus for detecting the leakage of liquid sodium includes a cable-like sensor adapted to be secured to a wall of piping or other equipment having sodium on the opposite side of the wall, and the sensor includes a core wire electrically connected to the wall through a leak current detector and a power source. An accidental leakage of the liquid sodium causes the corrosion of a metallic layer and an insulative layer of the sensor by products resulted from a reaction of sodium with water or oxygen in the atmospheric air so as to decrease the resistance between the core wire and the wall. Thus, the leakage is detected as an increase in the leaking electrical current. The apparatus is especially adapted for use in detecting the leakage of liquid sodium from sodium-conveying pipes or equipment in a fast breeder reactor.

MAVL wastes containers functional demonstration and associated tests program

International Nuclear Information System (INIS)

Templier, J.C.

2002-01-01

In the framework of studies on the MAVL wastes, the CEA develops containers for middle time wastes storage. This program aims to realize a ''B wastes containers'' demonstrator. A demonstrator is a container, parts of a container or samples which must validate the tests. This document presents the state of the study in the following three chapters: functions description, base data and design choices; presentation of the functional demonstrators; demonstration tests description. (A.L.B.)

On Leakage Current Measured at High Cell Voltages in Lithium-Ion Batteries

Energy Technology Data Exchange (ETDEWEB)

Vadivel, Nicole R.; Ha, Seungbum; He, Meinan; Dees, Dennis; Trask, Steve; Polzin, Bryant; Gallagher, Kevin G.

2017-01-01

In this study, parasitic side reactions in lithium-ion batteries were examined experimentally using a potentiostatic hold at high cell voltage. The experimental leakage current measured during the potentiostatic hold was compared to the Tafel expression and showed poor agreement with the expected transfer coefficient values, indicating that a more complicated expression could be needed to accurately capture the physics of this side reaction. Here we show that cross-talk between the electrodes is the primary contribution to the observed leakage current after the relaxation of concentration gradients has ceased. This cross-talk was confirmed with experiments using a lithium-ion conducting glass ceramic (LICGC) separator, which has high conductance only for lithium cations. The cells with LICGC separators showed significantly less leakage current during the potentiostatic hold test compared to cells with standard microporous separators where cross-talk is present. In addition, direct-current pulse power tests show an impedance rise for cells held at high potentials and for cells held at high temperatures, which could be attributed to film formation from the parasitic side reaction. Based on the experimental findings, a phenomenological mechanism is proposed for the parasitic side reaction which accounts for cross-talk and mass transport of the decomposition products across the separator.

Technical and management considerations in conducting type B shipping container tests

International Nuclear Information System (INIS)

Whitney, M.A.; Leader, D.R.; Phipps, D.P.

1994-01-01

The Code of Federal Regulations (CFR) mandate that type B shipping containers are capable of surviving specific drop tests. One approach for demonstrating compliance to the CFRs is to drop test a shipping container. This paper will discuss the technical and management considerations in conducting such drop tests on the 9975 family of shipping containers. For both technical and management considerations this paper will comment on loading the shipping container, dropping the shopping container, and examination of the shipping container after the drop tests

Explosion testing for the container venting system

International Nuclear Information System (INIS)

Cashdollar, K.L.; Green, G.M.; Thomas, R.A.; Demiter, J.A.

1993-01-01

As part of the study of the hazards of inspecting nuclear waste stored at the Hanford Site, the US Department of Energy and Westinghouse Hanford Company have developed a container venting system to sample the gases that may be present in various metal drums and other containers. In support of this work, the US Bureau of Mines has studied the probability of ignition while drilling into drums and other containers that may contain flammable gas mixtures. The Westinghouse Hanford Company drilling procedure was simulated by tests conducted in the Bureau's 8-liter chamber, using the same type of pneumatic drill that will be used at the Hanford Site. There were no ignitions of near-stoichiometric hydrogen-air or methane-air mixtures during the drilling tests. The temperatures of the drill bits and lids were measured by an infrared video camera during the drilling tests. These measured temperatures are significantly lower than the ∼500 degree C autoignition temperature of uniformly heated hydrogen-air or the ∼600 degree C autoignition temperature of uniformly heated methane-air. The temperatures are substantially lower than the 750 degree C ignition temperature of hydrogen-air and 1,220 degree C temperature of methane-air when heated by a 1-m-diameter wire

Radiation-induced off-state leakage current in commercial power MOSFETs

International Nuclear Information System (INIS)

Dodd, Paul Emerson; Shaneyfelt, Marty Ray; Draper, Bruce Leroy; Felix, James Andrew; Schwank, James Ralph; Dalton, Scott Matthew

2005-01-01

The total dose hardness of several commercial power MOSFET technologies is examined. After exposure to 20 krad(SiO 2 ) most of the n- and p-channel devices examined in this work show substantial (2 to 6 orders of magnitude) increases in off-state leakage current. For the n-channel devices, the increase in radiation-induced leakage current follows standard behavior for moderately thick gate oxides, i.e., the increase in leakage current is dominated by large negative threshold voltage shifts, which cause the transistor to be partially on even when no bias is applied to the gate electrode. N-channel devices biased during irradiation show a significantly larger leakage current increase than grounded devices. The increase in leakage current for the p-channel devices, however, was unexpected. For the p-channel devices, it is shown using electrical characterization and simulation that the radiation-induced leakage current increase is related to an increase in the reverse bias leakage characteristics of the gated diode which is formed by the drain epitaxial layer and the body. This mechanism does not significantly contribute to radiation-induced leakage current in typical p-channel MOS transistors. The p-channel leakage current increase is nearly identical for both biased and grounded irradiations and therefore has serious implications for long duration missions since even devices which are usually powered off could show significant degradation and potentially fail.

Radiologic assessment of spinal CSF leakage in spontaneous intracranial hypotension

International Nuclear Information System (INIS)

Han, Chang Jin; Kim, Ji Hyung; Kim, Jang Sung; Kim, Sun Yong; Suh, Jung Ho

1999-01-01

To assess the usefulness of imaging modalities in the detection of spinal CSF leakage in spontaneous intracranial hypotension. Fifteen patients who complained of postural headache without any preceding cause showed typical brain MR findings of intracranial hypotension, including radiologically confirmed CSF leakage. All fifteen underwent brain MRI and radionuclide cisternography. CT myelography was performed in eight patients and spinal MRI in six. Medical records, imaging findings and the incidence of spinal CSF leakage during each modality were retrospectively reviewed. CSF leakage was most common at the cervicothoracic junction, where in seven of 15 cases it was seen on radionuclide cisternography as increased focal paraspinal activity. Leakage was noted at the mid-tho-racic level in three patients, at the upper thoracic level in two, and at the cervical and lumbar levels in the remaining two. In two patients multiple CSF leaks were noted, and in all, early radioactive accumulation in the bladder was visualized. CT myelography revealed extrathecal and paraspinal contrast leakage in three of eight patients, and among those who underwent spinal MRI, dural enhancement was observed at the site of CSF leakage in all six, abnormal CSF signal in the neural foramen in one, and epidural CSF collection in one. Radionuclide cisternography is a useful method for the detection of CSF leakage in spontaneous intracranial hypotension. CT myelography and spinal MRI help determine the precise location of leakage

Waste container and method for containing waste

International Nuclear Information System (INIS)

Ono, Akira; Matsushita, Mitsuhiro; Doi, Makoto; Nakatani, Seiichi.

1990-01-01

In a waste container, water-proof membranes and rare earth element layers are formed on the inner surface of a steel plate concrete container in which steel plates are embedded. Further, rear earth element detectors are disposed each from the inner side of the steel plate concrete container by way of a pressure pipe to the outer side of the container. As a method for actually containing wastes, when a plurality of vessels in which wastes are fixed are collectively enhoused to the waste container, cussioning materials are attached to the inner surface of the container and wastes fixing containers are stacked successively in a plurality of rows in a bag made of elastic materials. Subsequently, fixing materials are filled and tightly sealed in the waste container. When the waste container thus constituted is buried underground, even if it should be deformed to cause intrusion of rain water to the inside of the container, the rare earth elements in the container dissolved in the rain water can be detected by the detectors, the containers are exchanged before the rain water intruding to the inner side is leached to the surrounding ground, to previously prevent the leakage of radioactive nuclides. (K.M.)

Facepiece leakage and fitting of respirators

International Nuclear Information System (INIS)

White, J.M.

1978-05-01

The ways in which airborne contaminants can penetrate respirators and the factors which affect the fit of respirators are discussed. The fit of the respirator to the face is shown to be the most critical factor affecting the protection achieved by the user. Qualitative and quantitative fit testing techniques are described and their application to industrial respirator programs is examined. Quantitative measurement of the leakage of a respirator while worn can be used to numerically indicate the protection achieved. These numbers, often referred to as protection factors, are sometimes used as the basis for selecting suitable respirators and this practice is reviewed. (author)

Description of leakage monitoring system at Angra 2 nuclear power plant primary circuit

International Nuclear Information System (INIS)

Costa, Lilian Rose Sobral da; Mendes, Jorge Eduardo de Souza

1999-01-01

This paper describes the Leakage Monitoring System installed in Angra 2 NPP. This system has the task of detecting, localizing and quantifying leaks in systems for which rupture preclusion is cited. These systems include the reactor coolant pressure boundary, the main steam and feedwater lines within the containment, and the main steam safety and relief valve station in the valve annex. (author)

Understanding and managing leakage in forest-based greenhouse-gas-mitigation projects.

Science.gov (United States)

Schwarze, Reimund; Niles, John O; Olander, Jacob

2002-08-15

A major concern about land use, land-use change and forestry (LULUCF) projects under the Clean Development Mechanism (CDM) is the potential for leakage. Leakage refers to a net increase of greenhouse-gas emissions in an area outside the project resulting from the CDM activity. This paper provides an overview of leakage, its definitions and its causes. It describes ways that LULUCF projects may suffer from leakage and attempts to assess the magnitude of leakage risks for different LULUCF project types. It also summarizes some of the approaches, both in terms of policies and project development, to address LULUCF leakage.

Project W320 52-inch diameter equipment container load test: Test report

International Nuclear Information System (INIS)

Bellomy, J.R.

1995-01-01

This test report summarizes testing activities and documents the results of the load tests performed on-site and off-site to structural qualify the 52-inch equipment containers designed and fabricated under Project W-320

The Effect of Gamma Radiation on the Bond Strength and Micro leakage of Two Aesthetic Restorative Materials

International Nuclear Information System (INIS)

Seif, M.B.

2013-01-01

To evaluate the effect of gamma radiation on bond strength and micro leakage of nano-composite and nano-glassionomer, and to detect any alterations in their molecular structure due to gamma radiation. Materials and Methods: 80 specimens were used as follow; 40 specimens for shear bond strength evaluation, 20 specimens for micro leakage assessment, while the remaining 20 specimens for deducing the chemical structure. For shear bond strength (SBS) test 2 mm thick wafers of dentine were sectioned and 3 mm diameter holes were drilled through the wafers. 20 specimens were restored with nano-composite and nano-glassionomer without irradiation (Group A1, B1). The remaining 20 specimens were restored with nano-composite and nano-glassionomer (Group A2, B2), then they were irradiated with therapeutic dose of 60 gray for 1 week (3 days/week). For micro leakage, 10 natural teeth with two prepared class V cavities were used. One of the cavities was restored with nano-composite while the other one with nano-glassionomer to be examined before and after gamma radiation. Spectrophotometric analysis was performed for all tested materials before and after radiation to trace any structural changes. Results: Significant increase in SBS of nano-composite after irradiation while nano-glassionomer was insignificantly increased. For micro leakage no significant difference existed between the irradiated and non-irradiated groups of both materials. Conclusion: Therapeutic dose of head and neck gamma radiation had improved dentin shear bond strength of nano-composite. On the other hand, it had not an effect on shear bond strength of nano-glassionomer and the micro leakage of both tested materials. Gamma radiation did not alter the chemical structure of the tested material.

Stress analysis of HLW containers advanced test work Compas project

International Nuclear Information System (INIS)

Ove Arup and Partners

1990-01-01

The Compas project is concerned with the structural performance of metal overpacks which may be used to encapsulate vitrified high-level waste forms before disposal in deep geological repositories. This document describes the activities performed between June and August 1989 forming the advanced test work phase of this project. This is the culmination of two years' analysis and test work to demonstrate whether the analytical ability exists to model containers subjected to realistic loads. Three mild steel containers were designed and manufactured to be one-third scale models of a realistic HLW container, modified to represent the effect of anisotropic loading and to facilitate testing. The containers were tested under a uniform external pressure and all failed by buckling in the mid-body region. The outer surface of each container was comprehensively strain-gauged to provide strain history data at all positions of interest. In parallel with the test work, Compas project partners, from five different European countries, independently modelled the behaviour of each of the containers using their computer codes to predict the failure pressure and produce strain history data at a number of specified locations. The first axisymmetric container was well modelled but predictions for the remaining two non-axisymmetric containers were much more varied, with differences of up to 50% occurring between failure predictions and test data

Experimental investigation of localized stress-induced leakage current distribution in gate dielectrics using array test circuit

Science.gov (United States)

Park, Hyeonwoo; Teramoto, Akinobu; Kuroda, Rihito; Suwa, Tomoyuki; Sugawa, Shigetoshi

2018-04-01

Localized stress-induced leakage current (SILC) has become a major problem in the reliability of flash memories. To reduce it, clarifying the SILC mechanism is important, and statistical measurement and analysis have to be carried out. In this study, we applied an array test circuit that can measure the SILC distribution of more than 80,000 nMOSFETs with various gate areas at a high speed (within 80 s) and a high accuracy (on the 10-17 A current order). The results clarified that the distributions of localized SILC in different gate areas follow a universal distribution assuming the same SILC defect density distribution per unit area, and the current of localized SILC defects does not scale down with the gate area. Moreover, the distribution of SILC defect density and its dependence on the oxide field for measurement (E OX-Measure) were experimentally determined for fabricated devices.

Detecting the leakage source of a reservoir using isotopes.

Science.gov (United States)

Yi, Peng; Yang, Jing; Wang, Yongdong; Mugwanezal, Vincent de Paul; Chen, Li; Aldahan, Ala

2018-07-01

A good monitoring method is vital for understanding the sources of a water reservoir leakage and planning for effective restoring. Here we present a combination of several tracers ( 222 Rn, oxygen and hydrogen isotopes, anions and temperature) for identification of water leakage sources in the Pushihe pumped storage power station which is in the Liaoning province, China. The results show an average 222 Rn activity of 6843 Bq/m 3 in the leakage water, 3034 Bq/m 3 in the reservoir water, and 41,759 Bq/m 3 in the groundwater. Considering that 222 Rn activity in surface water is typically less than 5000 Bq/m 3 , the low level average 222 Rn activity in the leakage water suggests the reservoir water as the main source of water. Results of the oxygen and hydrogen isotopes show comparable ranges and values in the reservoir and the leakage water samples. However, important contribution of the groundwater (up to 36%) was present in some samples from the bottom and upper parts of the underground powerhouse, while the leakage water from some other parts indicate the reservoir water as the dominant source. The isotopic finding suggests that the reservoir water is the main source of the leakage water which is confirmed by the analysis of anions (nitrate, sulfate, and chloride) in the water samples. The combination of these tracer methods for studying dam water leakage improves the accuracy of identifying the source of leaks and provide a scientific reference for engineering solutions to ensure the dam safety. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Use of fibrin glue in the prevention of leakage in pancreatico-jejunal anastomoses].

Science.gov (United States)

Stojanović, M; Jeremic, M; Stojanović, P; Stojiljković, M; Gmijović, D; Stanojković, Z; Savić, V; Djordjević, V; Cvetković, Z; Kostov, M; Colović, R

2002-01-01

The aim of this study was to test the protective effects of fibrin sealing on the pancreatico-jejunostomy (PJA), the high-risk anastomosis following pancreas head resection. Experimental study was performed on the mongrel dogs, divided in two groups (20 animals each): Experimental group-with end to end "dunking" PJA, protected by temporary occlusion of the pancreatic duct with fibrin sealant/Tissucol/Immuno Ag/, while control group was without any protective procedure. The animals were followed 5 months in order to study: protective effects of such procedure on the PJA quantified with the percent of anastomotic leakage, effects of the exocrine secretion and effects the endocrine function Results: PJA leakage occurred in 13.33% in control group. No leakage was registered in experimental group. Biochemical, histological and electron microscopic study showed slight transitory elevation of amylase levels. Fibrin glue plug was dissolved and pancreatic juice output was reestablished 12th days postoperatively. Long term follow-up showed no damages of the endocrine and exocrine pancreas. Pancreatic duct occlusion with fibrin glue appeared to be an useful method in the prevention of pancreatico-jejunostomy leakage, without negative effects on the exocrine and endocrine pancreas.

ACE puts containment venting systems to the test

International Nuclear Information System (INIS)

Merilo, M.

1990-01-01

Filtered venting of reactor containments has received considerable attention recently as a method for avoiding containment failure due to overpressure during severe accidents. Several proposed filtration devices have been tested in the internationally sponsored Advanced Containment Experiments (ACE) programme, such that a self consistent comparison of the aerosol removal characteristics of these systems could be obtained. Considering the different design, requirements and operating conditions of the filter devices, a direct comparison is not possible, nor appropriate. Nevertheless, large scale models, using full scale elements of the various devices whenever feasible, have been tested with consistent mixtures of aerosols and carrier gases. (author)

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

Junction leakage measurements with micro four-point probes

DEFF Research Database (Denmark)

Lin, Rong; Petersen, Dirch Hjorth; Wang, Fei

2012-01-01

We present a new, preparation-free method for measuring the leakage current density on ultra-shallow junctions. The junction leakage is found by making a series of four-point sheet resistance measurements on blanket wafers with variable electrode spacings. The leakage current density is calculated...... using a fit of the measured four-point resistances to an analytical two-sheet model. The validity of the approximation involved in the two-sheet model is verified by a comparison to finite element model calculations....

Trends in the development of reactor containments

International Nuclear Information System (INIS)

Turricchia, A.

1977-01-01

The paper presents a review of the technical developments which the containment systems of BWRs, PWRs and HWRs have undergone in the USA, Europe and Canada. The great variety of existing containment systems have been classified for each type of reactor, according to: principle of operation (i.e. dry containment; pressure suppression containment; containment with vacuum building; sub-atmospheric containment; etc.); type and number of the physical barriers provided against the dispersion of fission products to the environment (single containment, double containment, single containment with local collection of the leaks from the most probable leakage paths, or with pressurization of the potential leakage paths, etc.); and structural characteristics of the containment barriers (reinforced concrete, prestressed concrete, metal containment, liners). In the framework of this classification the main features of the various containment systems are illustrated, with special emphasis on the most modern designs. The difference in trend among various countries and various designers are highlighted. A review is also made of the various containment auxiliary systems which would operate in accident conditions (isolation systems, heat removal system, atmosphere control system, etc.). Also for these systems the main design criteria are set forth and present trends are described. Finally, a brief survey is also made of the present trends with regards to the design of containment structures against external events be they of natural origin (earthquake, tornadoes, etc.) or connected with human activities (airplane crash, explosions, etc.) [fr

Indocyanine green staining facilitates detection of bleb leakage during trabeculectomy.

Science.gov (United States)

Okazaki, Teruhiko; Kiuchi, Takahiro; Kawana, Keisuke; Oshika, Tetsuro

2007-03-01

To report a new technique to visualize bleb leakage using indocyanine green (ICG) staining during trabeculectomy. The ICG solution was widely applied over the filtering bleb including the conjunctival wound before completion of trabeculectomy. This procedure was performed in 48 eyes of 44 consecutive patients undergoing trabeculectomy between December 2004 and October 2005. Without staining, bleb leakage was not identified by the direct observation under the operating microscope. ICG staining clearly visualized aqueous leakage from the bleb in 5 eyes (10.4%). The bleb leakage in these eyes was easily repaired with 10-0 nylon sutures, and no eyes, including these 5 cases, showed bleb leakage after surgery. There were no intraoperative and postoperative complications related to ICG application. The application of ICG during trabeculectomy is a simple and useful technique to facilitate detection and repair of the bleb leakage.

Acceptance test report, 241-SY-101 Flexible Receiver System, Phase 1 testing

International Nuclear Information System (INIS)

Ritter, G.A.

1995-01-01

This document summarizes the results of the Phase 1 acceptance test of the 241-SY-101 Flexible Receiver System (FRS). This acceptance test consisted of a pressure-decay/leak test of the containment bag to verify that the seams along the length of the bag had been adequately sealed. The sealing integrity of the FRS must be verified to ensure that the release of waste and aerosols will be minimized during the removal of the test mixer pump from Tank 241-SY-101. The FRS is one of six major components of the Equipment Removal System, which has been designed to retrieve, transport, and store the mixer pump. This acceptance test was performed at Lancs Industries in Kirkland, Washington on January 17, 1995. The bag temperature-compensated pressure loss of 575 Pa was below the acceptance criteria of 625 Pa and the test results were therefore found to be acceptable. The bag manufacturer estimates that 80--90% of the pressure loss is attributed to leakage around the bag inflation valve where the pressure gage was connected. A leak detector was applied over the entire bag during the pre-tests and no leakage was found. Furthermore, the leak rate corresponding to this pressure loss is very small when compared to the acceptable leak rate of the completely assembled FRS. The sealing integrity of the assembled FRS is verified in Phase 3 testing

Routine testing on protective and safety systems and components

International Nuclear Information System (INIS)

Rysy, W.

1977-01-01

1) In-process inspection, tests during commissioning. 2) Tests during reactor operation. 2.1) Reactor protection system, for example: continuous auto-testing by a dynamic system, check of the output signals; 2.2) safety features: selected examples: functional tests on the ECCS, trial operation of the emergency diesels. 3) Tests during refuelling phase. 3.1) Containment: Leakage rate tests, leak testing; 3.2) coolant system: selected examples: inservice inspections of the pressure vessel, eddy current testing of the steam generator, functional tests of safety valves. (orig./HP) [de

Detection method of internal leakage from valve using acoustic method

International Nuclear Information System (INIS)

Kumagai, Hiromichi; Kitajima, Akira; Suzuki, Akio.

1990-01-01

The objective of this study is to estimate the feasibility of the acoustic method for the internal leakage from the valves in power plants. From the experimental results, it was suggested that the acoustic method for the monitoring of leakage was feasible. When the background levels are higher than the acoustic signals from leakage, we can detect the leakage analyzing the spectrum of the remainders which take the background noise from the acoustic signals. (author)

CONTAIN calculations

International Nuclear Information System (INIS)

Scholtyssek, W.

1995-01-01

In the first phase of a benchmark comparison, the CONTAIN code was used to calculate an assumed EPR accident 'medium-sized leak in the cold leg', especially for the first two days after initiation of the accident. The results for global characteristics compare well with those of FIPLOC, MELCOR and WAVCO calculations, if the same materials data are used as input. However, significant differences show up for local quantities such as flows through leakages. (orig.)

A Framework to Estimate CO2 Leakage associated with Geological Storage in Mature Sedimentary Basins

Science.gov (United States)

Celia, M. A.; Bachu, S.; Gasda, S.

2002-12-01

Geological storage of carbon dioxide requires careful risk analysis to avoid unintended consequences associated with the subsurface injection. Most negative consequences of subsurface injection are associated with leakage of the injected CO2 out of the geological formation into which it is injected. Such leakage may occur through natural geological features, including fractures and faults, or it may occur through human-created pathways such as existing wells. Possible leakage of CO2 through existing wells appears to be especially important in mature sedimentary basins that have been explored intensively and exploited for hydrocarbon production. In the Alberta Basin of western Canada, more than 300,000 oil and gas wells have been drilled, while in the state of Texas in the United States, more than 1,500,000 wells have been drilled. Many of these wells have been abandoned, and the information available to describe their current state is highly variable and sometimes nonexistent. Because these wells represent possible direct conduits from the injection zone to the land surface, a comprehensive assessment of leakage potential associated with these wells needs to be pursued. Analysis of leakage potential associated with existing wells must combine a data mining component with a multi-level modeling effort to assess leakage potential in a probabilistic framework. Information available for existing wells must be categorized and analyzed, and general leakage characteristics associated with wells of varying properties must be quantified. One example of a realistic target formation is the Viking Formation in Alberta, which is overlain by a thick shale layer and contains hydrocarbon in some locations. The existence of hydrocarbon in the formation indicates that the overlying shale layer is an effective barrier to flow, and therefore this is a good candidate formation for CO2 storage. However, the formation and its cap rock are punctured by approximately 180,000 wells, with

Combination Effect of Hemostatic and Disinfecting Agents on Micro-leakage of Restorations Bonded with Different Bonding Systems

Directory of Open Access Journals (Sweden)

Farhadpour H

2016-09-01

Full Text Available Statement of Problem: Hemostatic agents may affect the micro-leakage of different adhesive systems. Also, chlorhexidine has shown positive effects on micro-leakage. However, their interaction effect has not been reported yet. Objectives: To evaluate the effect of contamination with a hemostatic agent on micro- leakage of total- and self-etching adhesive systems and the effect of chlorhexidine application after the removal of the hemostatic agent. Materials and Methods: Standardized Class V cavity was prepared on each of the sixty caries free premolars at the cemento-enamel junction, with the occlusal margin located in enamel and the gingival margin in dentin. Then, the specimens were randomly divided into 6 groups (n = 10 according to hemostatic agent (H contamination, chlorhexidine (CHX application, and the type of adhesive systems (Adper Single Bond and Clearfil SE Bond used. After filling the cavities with resin composite, the root apices were sealed with utility wax. Furthermore, all the surfaces, except for the restorations and 1mm from the margins, were covered with two layers of nail varnish. The teeth were immersed in a 0.5% basic fuschin dye for 24 hours, rinsed, blot-dried and sectioned longitudinally through the center of the restorations bucco- lingualy. The sections were examined using a stereomicroscope and the extension of dye penetration was analyzed according to a non-parametric scale from 0 to 3. Statistical analysis was performed using Kruskal-Wallis test and Mann-Whitney U-test. Results: While ASB group showed no micro-leakage in enamel, none of the groups showed complete elimination of micro-leakage from the dentin. Regarding micro- leakage at enamel, and dentin margins, there was no significant difference between groups 1 and 2, 1 and 3, and 2 and 3 (p > 0.05. A significantly lower micro-leakage at the enamel and dentin margins was observed in group 3, compared to group 6. No significant difference was observed between

Radiation protection with consumer products containing gaseous tritium light sources

International Nuclear Information System (INIS)

Rahders, Erio; Haeusler, Uwe

2017-01-01

Consumer products containing gaseous tritium light sources (GTLS) were examined with respect to their radiological safety potential regarding leak tightness or accidents. The maximum tritium leakage rate of 2.7 Bq/d determined from experimental testing is well below the criterion for leak tightness of sealed radioactive sources in DIN 25426-4. In order to investigate the incorporation of tritium due to contact with consumer products, 2 scenarios were reviewed; the correct use of a tritium watch and the accident scenario with a keyring.

Measurement Methods to Determine Air Leakage Between Adjacent Zones

Energy Technology Data Exchange (ETDEWEB)

Hult, Erin L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dickerhoff, Darryl J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Phillip N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2012-09-01

Air leakage between adjacent zones of a building can lead to indoor air quality and energy efficiency concerns, however there is no existing standard for measuring inter-zonal leakage. In this study, synthesized data and field measurements are analyzed in order to explore the uncertainty associated with different methods for collecting and analyzing fan pressurization measurements to calculate interzone leakage.

Antimicrobial Peptide Lactoferricin B-Induced Rapid Leakage of Internal Contents from Single Giant Unilamellar Vesicles.

Science.gov (United States)

Moniruzzaman, Md; Alam, Jahangir Md; Dohra, Hideo; Yamazaki, Masahito

2015-09-29

Enzymatic digestion of bovine lactoferrin generates lactoferricin B (Lfcin B), a 25-mer peptide with strong antimicrobial activity of unknown mechanism. To elucidate the mechanistic basis of Lfcin B bactericidal activity, we investigated the interaction of Lfcin B with Escherichia coli and liposomes of lipid membranes. Lfcin B induced the influx of a membrane-impermeant fluorescent probe, SYTOX green, from the outside of E. coli into its cytoplasm. Lfcin B induced gradual leakage of calcein from large unilamellar vesicles (LUVs) of dioleoylphosphatidylglycerol (DOPG)/dioleoylphosphatidylcholine (DOPC) membranes. To clarify the cause of Lfcin B-induced leakage of calcein from the LUVs, we used the single giant unilamellar vesicle (GUV) method to investigate the interaction of Lfcin B with calcein-containing DOPG/DOPC-GUVs. We observed that a rapid leakage of calcein from a GUV started stochastically; statistical analysis provided a rate constant for Lfcin B-induced pore formation, kp. On the other hand, phase-contrast microscopic images revealed that Lfcin B induced a rapid leakage of sucrose from the single GUVs with concomitant appearance of a spherical GUV of smaller diameter. Because of the very fast leakage, and at the present time resolution of the experiments (33 ms), we could not follow the evolution of pore nor the process of the structural changes of the GUV. Here we used the term "local rupture" to express the rapid leakage of sucrose and determined the rate constant of local rupture, kL. On the basis of the comparison between kp and kL, we concluded that the leakage of calcein from single GUVs occurred as a result of a local rupture in the GUVs and that smaller pores inducing leakage of calcein were not formed before the local rupture. The results of the effect of the surface charge density of lipid membranes and that of salt concentration in buffer on kp clearly show that kp increases with an increase in the extent of electrostatic interactions due to

Incidence and management of pancreatic leakage after pancreatoduodenectomy

NARCIS (Netherlands)

de Castro, S. M. M.; Busch, O. R. C.; van Gulik, T. M.; Obertop, H.; Gouma, D. J.

2005-01-01

Background: Optimal management of severe pancreatic leakage after pancreatoduodenectomy can reduce morbidity and mortality. Completion pancreatectomy may be adequate but leads to endocrine insufficiency. This study evaluated an alternative management strategy for pancreatic leakage. Methods: Outcome

Containment test in area of high latitude and low temperature

International Nuclear Information System (INIS)

Cai Jiantao; Ni Yongsheng; Jia Wutong

2014-01-01

The effects of high latitude and low temperature on containment test are detailed analyzed from the view of design, equipment, construct and start-up, and the solution is put forward. The major problems resolved is as below: the effects of low temperature and high wind on defect inspection of the containment surface, the effects of test load on the affiliated equipment of containment in the condition of low temperature, and the effects of low temperature on the containment leak rate measurement. Application in Hongyanhe Unit 1 showed that the proposed scheme can effectively overcome the influence of adverse weather on the containment test. (authors)

Development of references of anomalies detection on P91 material using Self-Magnetic Leakage Field (SMLF) technique

Science.gov (United States)

Husin, Shuib; Afiq Pauzi, Ahmad; Yunus, Salmi Mohd; Ghafar, Mohd Hafiz Abdul; Adilin Sekari, Saiful

2017-10-01

This technical paper demonstrates the successful of the application of self-magnetic leakage field (SMLF) technique in detecting anomalies in weldment of a thick P91 materials joint (1 inch thickness). Boiler components such as boiler tubes, stub boiler at penthouse and energy piping such as hot reheat pipe (HRP) and H-balance energy piping to turbine are made of P91 material. P91 is ferromagnetic material, therefore the technique of self-magnetic leakage field (SMLF) is applicable for P91 in detecting anomalies within material (internal defects). The technique is categorized under non-destructive technique (NDT). It is the second passive method after acoustic emission (AE), at which the information on structures radiation (magnetic field and energy waves) is used. The measured magnetic leakage field of a product or component is a magnetic leakage field occurring on the component’s surface in the zone of dislocation stable slipbands under the influence of operational (in-service) or residual stresses or in zones of maximum inhomogeneity of metal structure in new products or components. Inter-granular and trans-granular cracks, inclusion, void, cavity and corrosion are considered types of inhomogeneity and discontinuity in material where obviously the output of magnetic leakage field will be shown when using this technique. The technique does not required surface preparation for the component to be inspected. This technique is contact-type inspection, which means the sensor has to touch or in-contact to the component’s surface during inspection. The results of application of SMLF technique on the developed P91 reference blocks have demonstrated that the technique is practical to be used for anomaly inspection and detection as well as identification of anomalies’ location. The evaluation of this passive self-magnetic leakage field (SMLF) technique has been verified by other conventional non-destructive tests (NDTs) on the reference blocks where simulated

Device for preventing leakage of coolant in nuclear fuel assembly

International Nuclear Information System (INIS)

Kobayashi, Yukio; Sekiguchi, Mamoru; Yoshida, Hideo.

1975-01-01

Object: To prevent leakage of coolant from between lower tie plate and channel box without causing deformation of the channel box and also without the possibility of disturbing the installation and removal of the box by the provision of a thin plate provided with leakage holes for the lower tie plate. Structure: Static water pressure within the lower tie plate is adapted to act upon the bear side of a flat plate for leakage prevention through leakage holes formed in the tie plate, thus urging the flat plate against the channel box inner surface. Meanwhile, static water pressure having been led through the leakage holes in the flat plate is adapted to press the flat plate in the vertical direction, thus urging the flat plate against the channel box inner surface and thereby preventing leakage of the coolant through a gap between the channel box and lower tie plate. (Yoshino, Y.)

Leakage current measurement in transformerless PV inverters

DEFF Research Database (Denmark)

Kerekes, Tamas; Sera, Dezso; Mathe, Laszlo

2012-01-01

Photovoltaic (PV) installations have seen a huge increase during the last couple of years. Transformerless PV inverters are gaining more share of the total inverter market, due to their high conversion efficiency, small weight and size. Nevertheless safety should have an important role in case...... of these tranformerless systems, due to the missing galvanic isolation. Leakage and fault current measurement is a key issue for these inverter topologies to be able to comply with the required safety standards. This article presents the test results of two different current measurement sensors that were suggested...

Use of coliform bacteria for the detection of on-line leakage in drinking water

International Nuclear Information System (INIS)

Bibi, S.; Karim, H.M.A.; Mashiatullah, A.; Sajjad, I.

1996-01-01

In this method, rupture or leakage in under ground water pipes is detected simply by taking the water samples from the main supply lines of the houses and incubating them at 40 deg. C for sixteen hours, colonies (developed with yellow colour) are counted with colony counter. Thirteen samples (in triplicate) collected from different houses in the congested localities during repair work of the major supply line and all of them after test showed heavy rate of pollution. The experiment was repeated for the same locality and sampling sites after completion of repair work. This time the rate of pollution decreases very much showing drastically low growth of microorganisms except for two points. For two further investigation of the nearly leakages at these points, 13 samples (in triplicate) were again collected in serial wise number of houses. Two points of the leakage were identified where the growth rate of the microorganisms was abruptly high between two consecutive houses or opposite houses depending upon the supply of water pipe lines showing the leakage of houses. Two points of the leakage were identified where the growth rate of the microorganisms was abruptly high between two consecutive houses or opposite houses depending upon the supply of water pipe lines showing the leakage of he pipes. This method is useful and causes no health hazard to the population and gives best results where the water supply is on intermittent basis. The technique is specially useful in the remote areas of the country where research facilities are not available and the Pacqualab is a field instrument. So it is handy and rapid method for the detection of leakage in underground water supplies in the remote areas of the country. (author)

Marginal leakage of two newer glass-ionomer-based sealant materials assessed using micro-CT.

NARCIS (Netherlands)

Chen, X.; Cuijpers, V.M.J.I.; Fan, M.; Frencken, J.E.F.M.

2010-01-01

OBJECTIVES: To test newer glass-ionomer-based materials as sealant materials. One glass-ionomer sealant was light-cured to obtain an early setting reaction. The null-hypothesis tested was: there is no difference in marginal leakage of sealants produced with high-viscosity glass-ionomer, with and

Prediction of leakage in the fixed mechanical seal

Directory of Open Access Journals (Sweden)

Asheichik Anatoly A.

2017-01-01

Full Text Available The questions of influence of the shape of contact surfaces on leakages through rubber seals in fixed connection of subassemblies are considered in the article. It is known from practice of operation of seals of various designs that the shape of contact surfaces and consequently also the shape of diagram of stresses in a contact zone considerably influences on value of leaks Linking leakage magnitude and distribution of contact stresses enables, firstly, more precisely calculate the amount of leakage for existing seals, and, secondly, to optimize the shape of the seals in their design in each case. As the result of experimental studies on the introduction of the rubber gasket ring fixed indenters different profiles found that by optimizing the shape of the indenter magnitude of leakage can be reduced by 10 times.

CMHC [Canadian Mortgage and Housing Corporation] research project: Testing of air barriers construction details

Energy Technology Data Exchange (ETDEWEB)

1991-08-26

The airtightness of building envelopes is important in controlling comfort and energy usage in houses. Leakage generally occurs through construction details, where there are joints or connections between materials, or where there are penetrations for services or other components. A study was conducted to quantify the air leakage characteristics of three such details in wood-frame walls: the header joist, the electric outlets, and the window opening detail. Three construction methods employed to achieve airtightness were evaluated: the sealed internal membrane approach (POLY); the external air barrier approach using a continuous vapour permeable membrane sandwiched between two layers of wall sheathing(EASE); and the airtight drywall approach (ADA). Test panels containing the details were subjected to air leakage testing at pressure differentials from 50 to 1,000 pascals. Measurements of air flow were made and evidence of failure of the barrier due to pressure loading was noted. Leakage rates for the header detail with the POLY, EASE and ADA panels were 24%, 18% and 10% respectively of that for the reference panel. For the electrical outlet joint, leakage rates for POLY and EASE panels were 24% and 36%, while the ADA panel had higher leakage rates than the traditional panel. For the window detail, leakage rates were lowest for the ADA panel and similar for the POLY and EASE panels; all were less than 15% that of traditional panels. 48 figs., 2 tabs.

Markovian Processes for Quantitative Information Leakage

DEFF Research Database (Denmark)

Biondi, Fabrizio

Quantification of information leakage is a successful approach for evaluating the security of a system. It models the system to be analyzed as a channel with the secret as the input and an output as observable by the attacker as the output, and applies information theory to quantify the amount...... and randomized processes with Markovian models and to compute their information leakage for a very general model of attacker. We present the QUAIL tool that automates such analysis and is able to compute the information leakage of an imperative WHILE language. Finally, we show how to use QUAIL to analyze some...... of information transmitted through such channel, thus effectively quantifying how many bits of the secret can be inferred by the attacker by analyzing the system’s output. Channels are usually encoded as matrices of conditional probabilities, known as channel matrices. Such matrices grow exponentially...

Leakage investigation in an underground cooling water pipeline at a thermal power station using radiotracer technique

International Nuclear Information System (INIS)

Khan, I.H.; Din, U.G.; Gul, S.; Farooq, M.; Qureshi, R.M.

2004-05-01

The objective of this study was to locate the leakage point(s) in an underground cooling water pipeline of a Thermal Power Station for pre-shutdown planning purposes. The internal diameter of the pipeline was 2240 mm with 12 mm with 12 (mild steel) wall thickness and it was buried under 1.0 meter reinforced concrete and 0.5-1.0 meter soil/sand cover. The volume flow rate of the pipeline was 29043 m/sup 3/hour at 2kg/cm/sup 2/ pressure. The linear speed of water flowing inside the pipeline was around 2 m/sec. This gave rise to a very high volume fast moving system. Radiotracer technique was used to investigate the problem under investigation. About 50 mCi of /sup 131/I radiotracer, in the form of NaI solution, was injected into the system and radiotracer evolution near suspected leakage point(s) was monitored using radiation detectors (NaI, 2 x 2 inch crystal size). Seven detectors were installed around three teeing off pipes (leakage area) inside the plant building and one at the injection point near the pump outlet. On line data acquisition system was used to acquire the radiotracer data. The leakage water was exiting from the floor just along the pipes carrying main flow of water. The time lag between the arrival, at detectors, of radiotracer flowing inside the pipeline and that present in the leakage water (outside the pipeline) was exploited to identify the position of leakage. The tracer test revealed that there was leakage at two points. The leakage at one point was small as compared at the other points. (author)

Cause elucidation of sodium leakage incident at `Monju` reactor. Vibration of thermometer due to fluid force

Energy Technology Data Exchange (ETDEWEB)

Iwata, Koji; Wada, Yusaku; Morishita, Masaki; Yamaguchi, Akira; Ichimiya, Masakazu [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

1997-01-01

This is a report of summarized results of investigation and analysis on fracture of thermometer which is direct reason of sodium leakage incident at the second main cooling system of fast breeder reactor `Monju`. Various surveys such as on various damage factors, on flowing power vibrational features containing flowing power vibrational test of thermometer, on evaluation of high cycle fatigue due to flowing power vibration and details on propagation of and fracture due to fatigue crack, on why only said thermometer damaged, and so forth were executed. As results of these examinations, a decision was arrived that high cycle fatigue due to vibration formed by fluid force (fluid force vibration) was a direct cause of the thermometer damage. (G.K.)

Evaluation of the Sealing Ability of Three Obturation Techniques Using a Glucose Leakage Test

Directory of Open Access Journals (Sweden)

Katarzyna Olczak

2017-01-01

Full Text Available The aim of this study was to evaluate the sealing ability of three different canal filling techniques. Sixty-four roots of extracted human maxillary anterior teeth were prepared using ProTaper® rotary instruments. The specimens were then randomly divided into 3 experimental groups (n=16 and 2 control groups (n=8. The root canals were filled using cold lateral compaction (CLC group, continuous wave condensation technique using the Elements Obturation Unit® (EOU group, and ProTaper obturators (PT group. For the negative control group, 8 roots were filled using lateral compaction as in the CLC group, and the teeth were covered twice with a layer of nail varnish (NCG group. Another 8 roots were filled using lateral compaction, but without sealer, and these were used as the positive control (PCG group. A glucose leakage model was used for quantitative evaluation of microleakage for 24 hours and 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12 weeks. No significant difference in the cumulative amount of leakage was found between the three experimental groups at all observation times. The lateral condensation of cold gutta-percha can guarantee a similar seal of canal fillings as can be achieved by using thermal methods, in the round canals.

Assessing Agulhas leakage

NARCIS (Netherlands)

van Sebille, E.

2009-01-01

Agulhas leakage, the water that flows from the Indian Ocean to the Atlantic Ocean, plays an important role in the circulation of the Atlantic Ocean. The magnitude of this flux of warm and saline Indian Ocean water into the much colder and fresher Atlantic Ocean can be related to the strength of the

Early results from an experimental program to determine the behavior of containment piping penetration bellows subjected to severe accident conditions

International Nuclear Information System (INIS)

Lambert, L.D.; Parks, M.B.

1994-01-01

Containment piping penetration bellows are an integral part of the pressure boundary in steel containments in the United States (US). Their purpose is to minimize loading on the containment shell caused by differential movement between the piping and the containment. This differential movement is typically caused by thermal gradients generated during startup and shutdown of the reactor, but can be caused by earthquake, a loss-of-coolant accident (LOCA), or ''severe'' accidents. In the event of a severe accident, the bellows would be subjected to pressure, temperature, and deflection well beyond the design basis. Most bellows are installed such that they would be subjected to elevated internal pressure, elevated temperature, axial compression, and lateral deflection during a severe accident. A few bellows would be subjected to external pressure and axial elongation, as well as elevated temperature and lateral deflection. The purpose of this experimental program is to examine the potential for leakage of containment bellows during a severe accident. The test series subjects bellows to various levels and combinations of internal pressure, elevated temperature, axial compression or elongation, and lateral deformation. The experiments are being conducted in two parts. For Part 1, all bellows specimens are tested in ''like-new'' condition, without regard for the possible degrading effect of corrosion that has been observed in some containment piping bellows in the US Part I testing, which included 13 bellows tests, has been completed. The second part of the experimental program, in which bellows are subjected to simulated corrosive environments prior to testing, has just just begun. The Part I experiments have shown that bellows in ''like-new'' condition can withstand elevated temperatures and pressures along with large deformations before leaking. In most cases, the like-new bellows were fully compressed without developing any leakage

Brush seal leakage performance with gaseous working fluids at static and low rotor speed conditions

Science.gov (United States)

Carlile, Julie A.; Hendricks, Robert C.; Yoder, Dennis A.

1992-01-01

The leakage performance of a brush seal with gaseous working fluids at static and low rotor speed conditions was studied. The leakage results included for air, helium, and carbon dioxide at several bristle/rotor interferences. Also, the effects of packing a lubricant into the bristles and also of reversing the pressure drop across the seal were studied. Results were compared to that of an annular seal at similar operating conditions. In order to generalize the results, they were correlated using corresponding state theory. The brush seal tested had a bore diameter of 3.792 cm (1.4930 in.), a fence height of 0.0635 cm (0.025 in.), and 1800 bristles/cm circumference (4500 bristles/in. circumference). Various bristle/rotor radial interferences were achieved by using a tapered rotor. The brush seal reduced the leakage in comparison to the annular seal, up to 9.5 times. Reversing the pressure drop across the brush seal produced leakage rates approximately the same as that of the annular seal. Addition of a lubricant reduced the leakage by 2.5 times. The air and carbon dioxide data were successfully correlated using corresponding state theory. However, the helium data followed a different curve than the air and carbon dioxide data.

Proof testing of an explosion containment vessel

Energy Technology Data Exchange (ETDEWEB)

Esparza, E.D. [Esparza (Edward D.), San Antonio, TX (United States); Stacy, H.; Wackerle, J. [Los Alamos National Lab., NM (United States)

1996-10-01

A steel containment vessel was fabricated and proof tested for use by the Los Alamos National Laboratory at their M-9 facility. The HY-100 steel vessel was designed to provide total containment for high explosives tests up to 22 lb (10 kg) of TNT equivalent. The vessel was fabricated from an 11.5-ft diameter cylindrical shell, 1.5 in thick, and 2:1 elliptical ends, 2 in thick. Prior to delivery and acceptance, three types of tests were required for proof testing the vessel: a hydrostatic pressure test, air leak tests, and two full design charge explosion tests. The hydrostatic pressure test provided an initial static check on the capacity of the vessel and functioning of the strain instrumentation. The pneumatic air leak tests were performed before, in between, and after the explosion tests. After three smaller preliminary charge tests, the full design charge weight explosion tests demonstrated that no yielding occurred in the vessel at its rated capacity. The blast pressures generated by the explosions and the dynamic response of the vessel were measured and recorded with 33 strain channels, 4 blast pressure channels, 2 gas pressure channels, and 3 displacement channels. This paper presents an overview of the test program, a short summary of the methodology used to predict the design blast loads, a brief description of the transducer locations and measurement systems, some of the hydrostatic test strain and stress results, examples of the explosion pressure and dynamic strain data, and some comparisons of the measured data with the design loads and stresses on the vessel.

Testing of a steel containment vessel model

International Nuclear Information System (INIS)

Luk, V.K.; Hessheimer, M.F.; Matsumoto, T.; Komine, K.; Costello, J.F.

1997-01-01

A mixed-scale containment vessel model, with 1:10 in containment geometry and 1:4 in shell thickness, was fabricated to represent an improved, boiling water reactor (BWR) Mark II containment vessel. A contact structure, installed over the model and separated at a nominally uniform distance from it, provided a simplified representation of a reactor shield building in the actual plant. This paper describes the pretest preparations and the conduct of the high pressure test of the model performed on December 11-12, 1996. 4 refs., 2 figs

Application of distributed optical fiber sensing technologies to the monitoring of leakage and abnormal disturbance of oil pipeline

Science.gov (United States)

Yang, Xiaojun; Zhu, Xiaofei; Deng, Chi; Li, Junyi; Liu, Cheng; Yu, Wenpeng; Luo, Hui

2017-10-01

To improve the level of management and monitoring of leakage and abnormal disturbance of long distance oil pipeline, the distributed optical fiber temperature and vibration sensing system is employed to test the feasibility for the healthy monitoring of a domestic oil pipeline. The simulating leakage and abnormal disturbance affairs of oil pipeline are performed in the experiment. It is demonstrated that the leakage and abnormal disturbance affairs of oil pipeline can be monitored and located accurately with the distributed optical fiber sensing system, which exhibits good performance in the sensitivity, reliability, operation and maintenance etc., and shows good market application prospect.

Enhanced ground bounce noise reduction in a low-leakage CMOS multiplier

Science.gov (United States)

Verma, Bipin Kumar; Akashe, Shyam; Sharma, Sanjay

2015-09-01

In this paper, various parameters are used to reduce leakage power, leakage current and noise margin of circuits to enhance their performance. A multiplier is proposed with low-leakage current and low ground bounce noise for the microprocessor, digital signal processors (DSP) and graphics engines. The ground bounce noise problem appears when a conventional power-gating circuit transits from sleep-to-active mode. This paper discusses a reduction in leakage current in the stacking power-gating technique by three modes - sleep, active and sleep-to-active. The simulation results are performed on a 4 × 4 carry-save multiplier for leakage current, active power, leakage power and ground bounce noise, and comparison made for different nanoscales. Ground bounce noise is limited to 90%. The leakage current of the circuit is decimated up to 80% and the active power is reduced to 31%. We performed simulations using cadence virtuoso 180 and 45 nm at room temperature at various supply voltages.

Estimation of leakage power and delay in CMOS circuits using parametric variation

Directory of Open Access Journals (Sweden)

Preeti Verma

2016-09-01

Full Text Available With the advent of deep-submicron technologies, leakage power dissipation is a major concern for scaling down portable devices that have burst-mode type integrated circuits. In this paper leakage reduction technique HTLCT (High Threshold Leakage Control Transistor is discussed. Using high threshold transistors at the place of low threshold leakage control transistors, result in more leakage power reduction as compared to LCT (leakage control transistor technique but at the scarifies of area and delay. Further, analysis of effect of parametric variation on leakage current and propagation delay in CMOS circuits is performed. It is found that the leakage power dissipation increases with increasing temperature, supply voltage and aspect ratio. However, opposite pattern is noticed for the propagation delay. Leakage power dissipation for LCT NAND gate increases up to 14.32%, 6.43% and 36.21% and delay decreases by 22.5%, 42% and 9% for variation of temperature, supply voltage and aspect ratio. Maximum peak of equivalent output noise is obtained as 127.531 nV/Sqrt(Hz at 400 mHz.

Dissolution test of herbal medicines containing Passiflora sp.

Directory of Open Access Journals (Sweden)

Ane R. T. Costa

2011-05-01

Full Text Available The dissolution test is an essential tool to assess the quality of herbal medicines in the solid dosage form for oral use. This work aimed to evaluate the dissolution behavior of three herbal medicines in the form of capsules and tablet containing Passiflora, produced with powder or dried extract. Assay of total flavonoids and dissolution methods were validated and obtained results allowed the quantification of flavonoids with precision, accuracy and selectivity. The percentage of total flavonoids found was 2% for capsule A (containing only powder, 0.97% for capsule B (containing only dried extract and 5.5% for tablet. Although the content was lower, the release of flavonoids present in the capsule containing dried extract was 12% higher over 30 min, with dissolved percentage values of 87 and 75, for the capsules containing extract and powder, respectively. The tablet containing dried extract presented dissolution of 76%, despite the higher content of flavonoids, which may be due to pharmacotechnical problems. Obtained data demonstrated the need to implement these tests in the quality control of herbal medicines, confirming the release of the active ingredients that underlie the pharmacological action of these medicines.

Leakage pattern of linear accelerator treatment heads from multiple vendors

International Nuclear Information System (INIS)

Lonski, P.R.; Taylor, M.L.; Franich, R.D.; Harty, P.; Clements, N.; Kron, T.

2011-01-01

Full text: Patient life expectancy post-radiotherapy is becoming longer. Therefore, secondary cancers caused by radiotherapy treatment have more time to develop. Increasing attention is being given to out-of-field dose resulting from scatter and accelerator head leakage. Dose leakage from equivalent positions on Varian600C, Varian21-X, Siemens Primus and Elekta Synergy-II linacs were measured with TLD 1 00 H dosimeter chips and compared. Treatment parameters such as field size and beam energy were altered. Leakage doses are presented as a percentage of the dose to isocentre (5 Gy). Results illustrate significant variations in leakage dose between linac models where no model emits consistently lower amounts of radiation leakage for all treatment parameters. Results are shown below. Leakage through the collimator assembly in different units is varying as a function of location and unit design by more than a factor of 10. Differences are more pronounced in comparing Varian or Elekta models, which are fitted with an additional collimator separate from the MLC leaves, to the Siemens model, which uses MLC leaves as its only secondary collimator. Further measurements are currently being taken at the patient plane with a directional detector system to determine the spatial distribution of high leakage sources.

Anastomotic leakage after anterior resection for rectal cancer

DEFF Research Database (Denmark)

Bulow, S.

2008-01-01

On the basis of the literature about anastomotic leakage after anterior resection for rectal cancer a review is presented of the frequency, potential risk factors and consequences of leakage. The risk factors are evaluated according to the level of scientific evidence of the individual background...

Development and testing of techniques for in-ground stabilization, size reduction, and safe removal of radioactive wastes stored in containments buried in ground

International Nuclear Information System (INIS)

Halliwell, Stephen; Christodoulou, Apostolos

2013-01-01

Since the 1950's radioactive wastes from a number of laboratories have been stored below ground at the Hanford site, Washington State, USA, in vertical pipe units (VPUs) made of five 200 litre drums without tops or bottoms, and in caissons, made out of corrugated pipe, or concrete and typically 2,500 mm in diameter. The VPU's are buried of the order of 2,100 mm below grade, and the caissons are buried of the order of 6,000 mm below grade. The waste contains fuel pieces, fission products, and a range of chemicals used in the laboratory processes. This can include various energetic reactants such as un-reacted sodium potassium (NaK), potassium superoxide (KO 2 ), and picric acid, as well as quantities of other liquids. The integrity of the containments is considered to present unacceptable risks from leakage of radioactivity to the environment. This paper describes the successful development and full scale testing of in-ground augering equipment, grouting systems and removal equipment for remediation and removal of the VPUs, and the initial development work to test the utilization of the same basic augering and grouting techniques for the stabilization, size reduction and removal of caissons. (authors)

The concept of leakage in threat assessment.

Science.gov (United States)

Meloy, J Reid; O'Toole, Mary Ellen

2011-01-01

Leakage in the context of threat assessment is the communication to a third party of an intent to do harm to a target. Third parties are usually other people, but the means of communication vary, and include letters, diaries, journals, blogs, videos on the internet, emails, voice mails, and other social media forms of transmission. Leakage is a type of warning behavior that typically infers a preoccupation with the target, and may signal the research, planning, and implementation of an attack. Nomothetic data suggest that leakage occurs in a majority of cases of attacks on and assassinations of public figures, adult mass murders, adolescent mass murders, and school or campus shootings: very low-frequency, but catastrophic acts of intended and targeted violence. Idiographic or case data illustrate the various permutations of leakage. We discuss the operational importance of the concept, place it in the context of other warning behaviors, emphasize the need for further research, and outline risk management strategies for the mitigation of such acts of violence in both law enforcement and clinical mental health settings. Copyright © 2011 John Wiley & Sons, Ltd.

Evaluation of the user seal check on gross leakage detection of 3 different designs of N95 filtering facepiece respirators.

Science.gov (United States)

Lam, Simon C; Lui, Andrew K F; Lee, Linda Y K; Lee, Joseph K L; Wong, K F; Lee, Cathy N Y

2016-05-01

The use of N95 respirators prevents spread of respiratory infectious agents, but leakage hampers its protection. Manufacturers recommend a user seal check to identify on-site gross leakage. However, no empirical evidence is provided. Therefore, this study aims to examine validity of a user seal check on gross leakage detection in commonly used types of N95 respirators. A convenience sample of 638 nursing students was recruited. On the wearing of 3 different designs of N95 respirators, namely 3M-1860s, 3M-1862, and Kimberly-Clark 46827, the standardized user seal check procedure was carried out to identify gross leakage. Repeated testing of leakage was followed by the use of a quantitative fit testing (QNFT) device in performing normal breathing and deep breathing exercises. Sensitivity, specificity, predictive values, and likelihood ratios were calculated accordingly. As indicated by QNFT, prevalence of actual gross leakage was 31.0%-39.2% with the 3M respirators and 65.4%-65.8% with the Kimberly-Clark respirator. Sensitivity and specificity of the user seal check for identifying actual gross leakage were approximately 27.7% and 75.5% for 3M-1860s, 22.1% and 80.5% for 3M-1862, and 26.9% and 80.2% for Kimberly-Clark 46827, respectively. Likelihood ratios were close to 1 (range, 0.89-1.51) for all types of respirators. The results did not support user seal checks in detecting any actual gross leakage in the donning of N95 respirators. However, such a check might alert health care workers that donning a tight-fitting respirator should be performed carefully. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Shielding design for testing room of large container scanner

International Nuclear Information System (INIS)

Liu Yisi; Miao Qitian; Zhou Liye

1997-01-01

Testing facility for large container scanner is a most advanced anti-smuggle tool. The X-ray scanning principle is adopted in this system. The X-ray was collimated a ted as a fan-shape beam. The accelerator only supplies the ray beam when the container is scanned. The irradiation time is less than one minute per test. The X-ray burst irradiation and highly collimated a ted scanning beam of this system is different from the common industrial irradiation accelerator. The shielding design of the 1:1 large container scanner introduced has better collimation level because of tri-collimation. The irradiation dose is less than 150 μGy per test, which is obviously lower than importations

Basic tests on integrity evaluation for natural hexafluoride transporting container

International Nuclear Information System (INIS)

Gomi, Yoshio; Yamakawa, Hidetsugu; Kato, Osamu; Kobayashi, Seiichi

1990-01-01

In this study, the affected factors that needed to integrity evaluation for UF 6 transporting 48Y cylinder, were confirmed by basic tests and preliminary analysis. The factors were the sealing parts and external surface emissivity that ruled both the behavior under fire accident condition and the fire resistance capability of the cylinder, and the external pressure resistance capability at the sunk accident. The results obtained as follows. (1) Confirming tests for fire resistance of cylinder valve and plug, seat leakage of the valve caused at 150 degrees C. by unequal thermal expansion between the valve body and the stem. The tin-lead solder coating the tapered thread of valve and plug, melted at 200 degrees C., then the sealing boundary broke. (2) An external emissivity influence to radiation heat transfer measured with test pieces heated by electric oven. The covered paints of the specimen burned and separated, the emissivity changed 0.4 to 0.6, dependent on the surrounding temperature. Type 48Y cylinder filled with 12.5 tons of UF 6 and the measured emissivity was used the computer code analysis. The hydraulic breaking did not happen under the fire accident condition at 800 degrees C., for 30 minutes. (3) The external pressure test of the valve endured the hydrostatic pressure at 3000 meters, which corresponded to about five times the cylinder body buckling strength. (author)

4D ERT Monitoring of Subsurface Water Pipe Leakage During a Controlled Field Experiment

Science.gov (United States)

Inauen, C.; Chambers, J. E.; Wilkinson, P. B.; Meldrum, P.; Swift, R. T.; Uhlemann, S.; Gunn, D.; Dashwood, B.; Taxil, J.; Curioni, G.

2016-12-01

Locating and delineating leakage from subsurface pipelines is an important task for civil engineers. 4D Electrical Resistivity Tomography (ERT) allows changes in subsurface resistivity to be imaged at a high spatial and temporal resolution in a minimally invasive manner. It is therefore a promising tool to supplement conventional point-sensing techniques to monitor subsurface flow processes. To assess the efficacy of ERT for pipe leakage monitoring several controlled leak experiments were carried out at a test site in Blagdon, Bristol, UK. To simulate the leak, a plastic pipe with a hole was buried below a flat, grassed area at a depth of 0.7 m, representing a standard UK mains water pipe installation. The water table at the site lies well below the surface meaning that the experiment took entirely place in the vadose zone, where changes in resistivity are primarily sensitive to water content variations. The ERT array covered an area of 6.5m x 6.5m around the leak location. Data acquisition was carried out with the BGS PRIME (Proactive Infrastructure Monitoring and Evaluation) system, which facilitates remote scheduling and autonomous ERT data collection and transmission. To obtain the resistivity changes of the subsurface a 4D inversion was carried out using a Gauss-Newton approach with spatial and temporal smoothness constraints. We were able to reliably observe the onset, spread and cessation of the leakage. Measurements from in-situ soil sensors at several depths above and below the leak complemented the ERT data and allowed us to assess their reliability and directly relate them to hydrogeological processes. Moreover, through experimental tests with soil samples from the test area, a Waxman-Smits relation was obtained to directly convert the changes in electrical resistivity to gravimetric soil moisture content. With future experiments on the test site more work is planned towards survey optimization, automated processing and tracking of leakage plumes.

Short-term effects of CO2 leakage on the soil bacterial community in a simulated gas leakage scenario.

Science.gov (United States)

Ma, Jing; Zhang, Wangyuan; Zhang, Shaoliang; Zhu, Qianlin; Feng, Qiyan; Chen, Fu

2017-01-01

The technology of carbon dioxide (CO 2 ) capture and storage (CCS) has provided a new option for mitigating global anthropogenic emissions with unique advantages. However, the potential risk of gas leakage from CO 2 sequestration and utilization processes has attracted considerable attention. Moreover, leakage might threaten soil ecosystems and thus cannot be ignored. In this study, a simulation experiment of leakage from CO 2 geological storage was designed to investigate the short-term effects of different CO 2 leakage concentration (from 400 g m -2 day -1 to 2,000 g m -2 day -1 ) on soil bacterial communities. A shunt device and adjustable flow meter were used to control the amount of CO 2 injected into the soil. Comparisons were made between soil physicochemical properties, soil enzyme activities, and microbial community diversity before and after injecting different CO 2 concentrations. Increasing CO 2 concentration decreased the soil pH, and the largest variation ranged from 8.15 to 7.29 ( p soil CO 2 concentration increased. The dominant phylum in the soil samples was Proteobacteria , whose proportion rose rapidly from 28.85% to 67.93%. In addition, the proportion of Acidobacteria decreased from 19.64% to 9.29% ( p soil ecosystems.

The containment and an absorbent evaluation for a package for a liquid radioactive isotope

Energy Technology Data Exchange (ETDEWEB)

Bang, K. S.; Lee, J. C.; Kim, D. H.; Hwang, C. S.; Kim, H. J.; Seo, K. S

2005-03-01

Radioactive isotopes must be safely transported from the production centre to the point of use. The shipping package to safely transport radioactive isotopes should be able to withstand the conditions prescribed by law. A type a package, which is used to transport liquid radioactive materials, should have a containment system comprising a primary inner and a secondary outer containment or it should be provided with a sufficiently absorbent material to absorb twice the volume of the liquid contents. Accordingly, an absorbent material for use in a Type A package to transport a liquid radioactive isotope was estimated. To estimate the integrity of containment, the leakage tests for a containment system for a Type A package for domestic and abroad expert were conducted.

Lung protein leakage in feline septic shock.

Science.gov (United States)

Schützer, K M; Larsson, A; Risberg, B; Falk, A

1993-06-01

The aim of the present study was to explore lung microvascular leakage of protein and water in a feline model of septic shock, using a double isotope technique with external gamma camera detection and gravimetric lung water measurements. The experiments were performed on artificially ventilated cats. One group of cats (n = 8) was given an infusion of live Escherichia coli bacteria, and another group (n = 5) served as a control group receiving saline. Plasma transferrin was radiolabeled in vivo with indium-113m-chloride, and erythrocytes were labeled with technetium-99m. The distribution of these isotopes in the lungs was continuously measured with a gamma camera. A normalized slope index (NSI) was calculated, indicative of the transferrin accumulation corrected for changes in local blood volume that reflect protein leakage. In the septic group there was a protein leakage after bacterial infusion, with a NSI of 39 x 10(-4) +/- 5 x 10(-4) min-1 (mean +/- SEM), and the PaO2 diminished from 21 +/- 1 to 9.5 +/- 1 kPa. In control cats a slight protein leakage with a NSI of 9 +/- 10(-4) +/- 2 x 10(-4) min-1 was detected, probably caused by the operative procedure, but PaO2 did not change. Wet-to-dry-weight ratios of postmortem lungs were not significantly different between the groups. It was concluded that an intravenous infusion of live E. coli bacteria induces a lung capillary protein leakage without increased lung water and a concomitantly disturbed gas exchange.(ABSTRACT TRUNCATED AT 250 WORDS)

Leakage-Resilient Cryptography from the Inner-Product Extractor

DEFF Research Database (Denmark)

Dziembowski, Stefan; Faust, Sebastian

2011-01-01

We present a generic method to secure various widely-used cryptosystems against arbitrary side-channel leakage, as long as the leakage adheres three restrictions: first, it is bounded per observation but in total can be arbitrary large. Second, memory parts leak independently, and, third, the ran...

Hunting the unknown: White-box database leakage detection

NARCIS (Netherlands)

Costante, E.; Hartog, den J.I.; Petkovic, M.; Etalle, S.; Pechenizkiy, M.; Atluri, V.; Pernul, G.

2014-01-01

Data leakage causes significant losses and privacy breaches worldwide. In this paper we present a white-box data leakage detection system to spot anomalies in database transactions. We argue that our approach represents a major leap forward w.r.t. previous work because: i) it significantly decreases

Sealing ability of MTA, CPM, and MBPc as root-end filling materials: a bacterial leakage study.

Science.gov (United States)

Medeiros, Paulo Leal; Bernardineli, Norberti; Cavenago, Bruno Cavalini; Torres, Sérgio Aparecido; Duarte, Marco Antonio Hungaro; Bramante, Clovis Monteiro; Marciano, Marina Angélica

2016-04-01

Objectives To evaluate the sealing ability of three root-end filling materials (white MTA, CPM, and MBPc) using an Enterococcus faecalis leakage model. Material and Methods Seventy single-root extracted human teeth were instrumented and root-ends were resected to prepare 3 mm depth cavities. Root-end preparations were filled with white MTA, CPM, and MBPc cements. Enterococcus faecalis was coronally introduced and the apical portion was immersed in BHI culture medium with phenol red indicator. The bacterial leakage was monitored every 24 h for 4 weeks. The statistical analysis was performed using the Wilcoxon-Gehan test (pCPM and the other groups. Conclusions The epoxy resin-based cement MBPc had lower bacterial leakage compared with the calcium silicate-based cements MTA and CPM.

LEAF: a computer program to calculate fission product release from a reactor containment building for arbitrary radioactive decay chains

International Nuclear Information System (INIS)

Lee, C.E.; Apperson, C.E. Jr.; Foley, J.E.

1976-10-01

The report describes an analytic containment building model that is used for calculating the leakage into the environment of each isotope of an arbitrary radioactive decay chain. The model accounts for the source, the buildup, the decay, the cleanup, and the leakage of isotopes that are gas-borne inside the containment building

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.

Detection and quantification of methane leakage from landfills

Energy Technology Data Exchange (ETDEWEB)

Ljungberg, Sven-Aake; Maartensson, Stig-Goeran (Univ. of Gaevle, Gaevle (Sweden)); Meijer, Jan-Erik; Rosqvist, Haakan (NSR AB, Helsingborg (Sweden))

2009-03-15

with different ground humidity showed that pores in the surface layer close when the moisture content is greater, reducing the landfill gas leakage. The large and sometimes rapid changes make it very difficult to get a picture of the distribution of the methane leakage over the landfill surfaces. Methane emissions were measured in different seasons, and also when the landfill surfaces had snow cover. The results showed that methane is emitted easily through porous snow. The same methane concentrations were recorded for GPS-fixed leakage features with and without snow cover. If the objective is to produce a reliable measurement of gas emission from a landfill, the combination of laser/chamber method is probably not sufficiently accurate. However, if the objective is, for example, to determine and prioritise where measures should be taken at different landfill surfaces to reduce emission, the combination of laser and the chamber method is very usable. The measurement method tested was application-oriented, and the aim was that the measurements would provide information on which to base the planning and implementation of short- and long-term measures. Manuals were produced for the laser instrument and the IR camera, showing how the two instruments are to be used for detecting methane emissions from landfills. The project demonstrated how the laser instrument could be used by bouncing the beam off a simple reflector. Measurement using a beam path length of up to 200 m is possible. Examples of such applications are measurements over leachate ponds, beside a landfill and on parts of a landfill. Such measurements can give important information about emission conditions that are difficult to measure in any other way. Geoelectrical measurements have several areas of application for landfills, primarily in studies of groundwater pollution. In recent years, interest has also grown in investigating processes inside landfills. Based on results from previous studies, one of the aims

Influence of dental bleaching on marginal leakage of Class V restorations

Directory of Open Access Journals (Sweden)

Andréia Cristina Ramos Dorini

2010-04-01

Full Text Available Objective: Evaluate the in vitro effect of bleaching performed in the dental office and waiting time on the degree of microleakage in class V cavities with margins in enamel, restored with resin composite. Methods: Forty-five human third molars were used, in which the vestibular faces were bleached with 35% hydrogen peroxide activated with LED and the palatine faces were not bleached (control. The teeth were randomly divided into 3 groups with 15 teeth in each: Group 1, restored immediately after bleaching; Group 2, seven days after bleaching; and Group 3, fourteen days after bleaching. After cavity preparation, 35% phosphoric acid, Adper Single Bond 2 adhesive (3M ESPE, St. Paul, Mn, USA, and resin composite Filtek Z250 (3M ESPE, St. Paul, MN, USA were applied. The teeth were thermal cycled and sealed with red nail polish on the bleached faces and blue on the non bleached faces, except for 1mm around the restored region. The samples were classified according to the following scores: 0 = no leakage, 1 = minimum leakage (less than 1 / 3 the length of the wall, 2 = moderate leakage (1/3 to 2/3 of the wall and 3 = extensive leakage (over 2/3 of the wall. The data were submitted to the Kruskal-Wallis test at a level of significance of 5%. Results: The restorative procedure immediately after bleaching resulted in statistically higher microleakage values (p 0.05. Conclusion: Based on the results, it is advisable to wait at least 7 days after bleaching to make the definitive restoration.

Mechanism of leakage of ion-implantation isolated AlGaN/GaN MIS-high electron mobility transistors on Si substrate

Science.gov (United States)

Zhang, Zhili; Song, Liang; Li, Weiyi; Fu, Kai; Yu, Guohao; Zhang, Xiaodong; Fan, Yaming; Deng, Xuguang; Li, Shuiming; Sun, Shichuang; Li, Xiajun; Yuan, Jie; Sun, Qian; Dong, Zhihua; Cai, Yong; Zhang, Baoshun

2017-08-01

In this paper, we systematically investigated the leakage mechanism of the ion-implantation isolated AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) on Si substrate. By means of combined DC tests at different temperatures and electric field dependence, we demonstrated the following original results: (1) It is proved that gate leakage is the main contribution to OFF-state leakage of ion-implantation isolated AlGaN/GaN MIS-HEMTs, and the gate leakage path is a series connection of the gate dielectric Si3N4 and Si3N4-GaN interface. (2) The dominant mechanisms of the leakage current through LPCVD-Si3N4 gate dielectric and Si3N4-GaN interface are identified to be Frenkel-Poole emission and two-dimensional variable range hopping (2D-VRH), respectively. (3) A certain temperature annealing could reduce the density of the interface state that produced by ion implantation, and consequently suppress the interface leakage transport, which results in a decrease in OFF-state leakage current of ion-implantation isolated AlGaN/GaN MIS-HEMTs.

Quantifying information leakage of randomized protocols

DEFF Research Database (Denmark)

Biondi, Fabrizio; Legay, Axel; Malacaria, Pasquale

2015-01-01

The quantification of information leakage provides a quantitative evaluation of the security of a system. We propose the usage of Markovian processes to model deterministic and probabilistic systems. By using a methodology generalizing the lattice of information approach we model refined attackers...... capable to observe the internal behavior of the system, and quantify the information leakage of such systems. We also use our method to obtain an algorithm for the computation of channel capacity from our Markovian models. Finally, we show how to use the method to analyze timed and non-timed attacks...

Quantifying Information Leakage of Randomized Protocols

DEFF Research Database (Denmark)

Biondi, Fabrizio; Wasowski, Andrzej; Legay, Axel

2013-01-01

The quantification of information leakage provides a quantitative evaluation of the security of a system. We propose the usage of Markovian processes to model and analyze the information leakage of deterministic and probabilistic systems. We show that this method generalizes the lattice...... of information approach and is a natural framework for modeling refined attackers capable to observe the internal behavior of the system. We also use our method to obtain an algorithm for the computation of channel capacity from our Markovian models. Finally, we show how to use the method to analyze timed...

Detection of cerebrospinal fluid leakage by specific measurement of transferrin glycoforms.

Science.gov (United States)

Kwon, Seok-Joon; Zhang, Fuming; Dordick, Jonathan S; Sonstein, William J; Linhardt, Robert J

2015-10-01

A simple and rapid detection of cerebrospinal fluid (CSF) leakage would benefit spine surgeons making critical postoperative decisions on patient care. We have assessed novel approaches to selectively determine CSF β2-transferrin (β2TF), an asialo-transferrin (aTF) biomarker, without interference from serum sialo-transferrin (sTF) in test samples. First, we performed mild periodate oxidation to selectively generate aldehyde groups in sTF for capture with magnetic hydrazide microparticles, and selective removal with a magnetic separator. Using this protocol sTF was selectively removed from mixtures of CSF and serum containing CSF aTF (β2TF) and serum sTF, respectively. Second, a two-step enzymatic method was developed with neuraminidase and galactose oxidase for generating aldehyde groups in sTF present in CSF and serum mixtures for magnetic hydrazide microparticle capture. After selectively removing sTF from mixtures of CSF and serum, ELISA could detect significant TF signal only in CSF, while the TF signal in serum was negligible. The new approach for selective removal of only sTF in test samples will be promising for the required intervention by a spine surgeon. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Studies of axial-leakage simulations for homogeneous and heterogeneous EBR-II core configurations

International Nuclear Information System (INIS)

Grimm, K.N.; Meneghetti, D.

1985-08-01

When calculations of flux are done in less than three dimensions, leakage-absorption cross sections are normally used to model leakages (flows) in the dimensions for which the flux is not calculated. Since the neutron flux is axially dependent, the leakages, and hence the leakage-absorption cross sections, are also axially dependent. Therefore, to obtain axial flux profiles (or reaction rates) for individual subassemblies, an XY-geometry calculation delineating each subassembly has to be done at several axial heights with space- and energy-dependent leakage-absorption cross sections that are appropriate for each height. This report discusses homogeneous and heterogeneous XY-geometry calculations at various axial locations and using several differing assumptions for the calculation of the leakage-absorption cross section. The positive (outward) leakage-absorption cross sections are modeled as actual leakage absorptions, but the negative (inward) leakage-absorption cross sections are modeled as either negative leakage absorptions (+-B 2 method) or positive downscatter cross sections [the Σ/sub s/(1 → g) method]. 3 refs., 52 figs., 10 tabs

Spent fuel cladding containment credit test

International Nuclear Information System (INIS)

Wilson, C.N.

1983-01-01

As an initial step in addressing the effectiveness of breached cladding as a barrier to radionuclide release from the repository during the post-containment period, preliminary scoping tests have been initiated which compare radionuclide releases from spent fuel specimens with artificially induced cladding defects of various severities. The artificially induced defects are all more severe than the typical in-reactor type breaches which are expected to be the principal type of breach entering the repository for terminal storage. These preliminary scoping tests being conducted by Westinghouse Hanford Company for the Lawrence Livermore National Laboratory Waste Package Development Program in support of the Tuff repository project at the Nevada Test Site are described. Also included in this presentation are selected initial results from these tests. 22 figures