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Sample records for 1c shield design

  1. Magnetic shielding design analysis

    International Nuclear Information System (INIS)

    Two passive magnetic-shielding-design approaches for static external fields are reviewed. The first approach uses the shielding solutions for spheres and cylinders while the second approach requires solving Maxwell's equations. Experimental data taken at LLNL are compared with the results from these shieldings-design methods, and improvements are recommended for the second method. Design considerations are discussed here along with the importance of material gaps in the shield

  2. New Toroid shielding design

    CERN Multimedia

    Hedberg V

    On the 15th of June 2001 the EB approved a new conceptual design for the toroid shield. In the old design, shown in the left part of the figure above, the moderator part of the shielding (JTV) was situated both in the warm and cold areas of the forward toroid. It consisted both of rings of polyethylene and hundreds of blocks of polyethylene (or an epoxy resin) inside the toroid vacuum vessel. In the new design, shown to the right in the figure above, only the rings remain inside the toroid. To compensate for the loss of moderator in the toroid, the copper plug (JTT) has been reduced in radius so that a layer of borated polyethylene can be placed around it (see figure below). The new design gives significant cost-savings and is easier to produce in the tight time schedule of the forward toroid. Since the amount of copper is reduced the weight that has to be carried by the toroid is also reduced. Outgassing into the toroid vacuum was a potential problem in the old design and this is now avoided. The main ...

  3. Shielding Design and Radiation Shielding Evaluation for LSDS System Facility

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Younggook; Kim, Jeongdong; Lee, Yongdeok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    As the system characteristics, the target in the spectrometer emits approximately 1012 neutrons/s. To efficiently shield the neutron, the shielding door designs are proposed for the LSDS system through a comparison of the direct shield and maze designs. Hence, to guarantee the radiation safety for the facility, the door design is a compulsory course of the development of the LSDS system. To improve the shielding rates, 250x250 covering structure was added as a subsidiary around the spectrometer. In this study, the evaluations of the suggested shielding designs were conducted using MCNP code. The suggested door design and covering structures can shield the neutron efficiently, thus all evaluations of all conditions are satisfied within the public dose limits. From the Monte Carlo code simulation, Resin(Indoor type) and Tungsten(Outdoor type) were selected as the shielding door materials. From a comparative evaluation of the door thickness, In and Out door thickness was selected 50 cm.

  4. Castor-1C spent fuel storage cask decay heat, heat transfer, and shielding analyses

    International Nuclear Information System (INIS)

    This report documents the decay heat, heat transfer, and shielding analyses of the Gesellschaft fuer Nuklear Services (GNS) CASTOR-1C cask used in a spent fuel storage demonstration performed at Preussen Elektra's Wurgassen nuclear power plant. The demonstration was performed between March 1982 and January 1984, and resulted in cask and fuel temperature data and cask exterior surface gamma-ray and neutron radiation dose rate measurements. The purpose of the analyses reported here was to evaluate decay heat, heat transfer, and shielding computer codes. The analyses consisted of (1) performing pre-look predictions (predictions performed before the analysts were provided the test data), (2) comparing ORIGEN2 (decay heat), COBRA-SFS and HYDRA (heat transfer), and QAD and DOT (shielding) results to data, and (3) performing post-test analyses if appropriate. Even though two heat transfer codes were used to predict CASTOR-1C cask test data, no attempt was made to compare the two codes. The codes are being evaluated with other test data (single-assembly data and other cask data), and to compare the codes based on one set of data may be premature and lead to erroneous conclusions

  5. New facility shield design criteria

    International Nuclear Information System (INIS)

    The purpose of the criteria presented here is to provide standard guidance for the design of nuclear radiation shields thoughout new facilities. These criteria are required to assure a consistent and integrated design that can be operated safely and economically within the DOE standards. The scope of this report is confined to the consideration of radiation shielding for contained sources. The whole body dose limit established by the DOE applies to all doses which are generally distributed throughout the trunk of the body. Therefore, where the whole body is the critical organ for an internally deposited radionuclide, the whole body dose limit applies to the sum of doses received must assure control of the concentration of radionuclides in the building atmosphere and thereby limit the dose from internal sources

  6. MFTF-α + T shield design

    International Nuclear Information System (INIS)

    MFTF-α+T is a DT upgrade option of the Tandem Mirror Fusion Test Facility (MFTF-B) to study better plasma performance, and test tritium breeding blankets in an actual fusion reactor environment. The central cell insert, designated DT axicell, has a 2-MW/m2 neutron wall loading at the first wall for blanket testing. This upgrade is completely shielded to protect the reactor components, the workers, and the general public from the radiation environment during operation and after shutdown. The shield design for this upgrade is the subject of this paper including the design criteria and the tradeoff studies to reduce the shield cost

  7. Shielding design for better plant availability

    International Nuclear Information System (INIS)

    Design methods are described for providing a shield system for nuclear power plants that will facilitate maintenance and inspection, increase overall plant availability, and ensure that man-rem exposures are as low as practicable

  8. Shielding Design for a Medical Cyclotron

    Institute of Scientific and Technical Information of China (English)

    WANG; Feng; SONG; Guo-fang; GUAN; Feng-ping; LV; Yin-long; ZHANG; Xing-zhi

    2012-01-01

    <正>A 10 MeV 100 μA medical cyclotron is constructed at CIAE which is used in the production of FDG. The energy of the cyclotron can reach 14 MeV by adjusting the magnetic field and RF system parameters, and the shielding design is in accordance with the 14 MeV beam energy. In this shielding design only neutron is considered, and the neutron source is produced by proton

  9. Design of ITER shielding blanket

    International Nuclear Information System (INIS)

    A mechanical configuration of ITER integrated primary first wall/shield blanket module were developed focusing on the welded attachment of its support leg to the back plate. A 100 mm x 150 mm space between the legs of adjacent modules was incorporated for the working space of welding/cutting tools. A concept of coolant branch pipe connection to accommodate deformation due to the leg welding and differential displacement of the module and the manifold/back plate during operation was introduced. Two-dimensional FEM analyses showed that thermal stresses in Cu-alloy (first wall) and stainless steel (first wall coolant tube and shield block) satisfied the stress criteria following ASME code for ITER BPP operation. On the other hand, three-dimensional FEM analyses for overall in-vessel structures exhibited excessive primary stresses in the back plate and its support structure to the vacuum vessel under VDE disruption load and marginal stresses in the support leg of module No.4. Fabrication procedure of the integrated primary first wall/shield blanket module was developed based on single step solid HIP for the joining of Cu-alloy/Cu-alloy, Cu-alloy/stainless steel, and stainless steel/stainless steel. (author)

  10. Shielding design to obtain compact marine reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yamaji, Akio; Sako, Kiyoshi (Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment)

    1994-06-01

    The marine reactors equipped in previously constructed nuclear ships are in need of the secondary shield which is installed outside the containment vessel. Most of the weight and volume of the reactor plants are occupied by this secondary shield. An advanced marine reactor called MRX (Marine Reactor X) has been designed to obtain a more compact and lightweight marine reactor with enhanced safety. The MRX is a new type of marine reactor which is an integral PWR (The steam generator is installed in the pressure vessel.) with adopting a water-filled containment vessel and a new shielding design method of no installation of the secondary shield. As a result, MRX is considerably lighter in weight and more compact in size as compared with the reactors equipped in previously constructed nuclear ships. For instance, the plant weight and volume of the containment vessel of MRX are about 50% and 70% of those of the Nuclear Ship MUTSU, in spite of the power of MRX is 2.8 times as large as the MUTSU's reactor. The shielding design calculation was made using the ANISN, DOT3.5, QAD-CGGP2 and ORIGEN codes. The computational accuracy was confirmed by experimental analyses. (author).

  11. Preliminary Thermal Design of Cryogenic Radiation Shielding

    Science.gov (United States)

    Li, Xiaoyi; Mustafi, Shuvo; Boutte, Alvin

    2015-01-01

    Cryogenic Hydrogen Radiation Shielding (CHRS) is the most mass efficient material radiation shielding strategy for human spaceflight beyond low Earth orbit (LEO). Future human space flight, mission beyond LEO could exceed one year in duration. Previous radiation studies showed that in order to protect the astronauts from space radiation with an annual allowable radiation dose less than 500 mSv, 140 kgm2 of polyethylene is necessary. For a typical crew module that is 4 meter in diameter and 8 meter in length. The mass of polyethylene radiation shielding required would be more than 17,500 kg. The same radiation study found that the required hydrogen shielding for the same allowable radiation dose is 40 kgm2, and the mass of hydrogen required would be 5, 000 kg. Cryogenic hydrogen has higher densities and can be stored in relatively small containment vessels. However, the CHRS system needs a sophisticated thermal system which prevents the cryogenic hydrogen from evaporating during the mission. This study designed a cryogenic thermal system that protects the CHRS from hydrogen evaporation for one to up to three year mission. The design also includes a ground based cooling system that can subcool and freeze liquid hydrogen. The final results show that the CHRS with its required thermal protection system is nearly half of the mass of polyethylene radiation shielding.

  12. Design and Analysis of HJ-1-C Satellite SAR Antenna

    Directory of Open Access Journals (Sweden)

    Zheng Shi-kun

    2014-06-01

    Full Text Available With truss deployable mesh parabolic reflector, the HJ-1-C SAR antenna has complex structure and multiple steps during the deployed processing. The design of the antenna is difficult in terms of deployed reliability and electrical performance. This paper makes intensive research on system, structure and electrical design, and the analysis of mechanical and thermal performance in the actual space conditions is also presented. The successful deploying in orbit and high image quality of the HJ-1-C satellite indicate that the mechanical, electronic, thermal and reliability design of the antenna satisfy the project requirement, and these research provides valuable experience for the design of the centralized mesh parabolic SAR antenna.

  13. Design and Analysis of HJ-1-C Satellite SAR Antenna

    OpenAIRE

    Zheng Shi-kun; Ji You-zhi; Cui Zhao-yun; Fang Yong-gang; Zhou Li-ping

    2014-01-01

    With truss deployable mesh parabolic reflector, the HJ-1-C SAR antenna has complex structure and multiple steps during the deployed processing. The design of the antenna is difficult in terms of deployed reliability and electrical performance. This paper makes intensive research on system, structure and electrical design, and the analysis of mechanical and thermal performance in the actual space conditions is also presented. The successful deploying in orbit and high image quality of the HJ-1...

  14. Summary of Prometheus Radiation Shielding Nuclear Design Analyses , for information

    International Nuclear Information System (INIS)

    This report transmits a summary of radiation shielding nuclear design studies performed to support the Prometheus project. Together, the enclosures and references associated with this document describe NRPCT (KAPL and Bettis) shielding nuclear design analyses done for the project

  15. Summary of Prometheus Radiation Shielding Nuclear Design Analysis

    Energy Technology Data Exchange (ETDEWEB)

    J. Stephens

    2006-01-13

    This report transmits a summary of radiation shielding nuclear design studies performed to support the Prometheus project. Together, the enclosures and references associated with this document describe NRPCT (KAPL & Bettis) shielding nuclear design analyses done for the project.

  16. Advanced materials and design for electromagnetic interference shielding

    CERN Document Server

    Tong, Xingcun Colin

    2008-01-01

    Exploring the role of EMI shielding in EMC design, this book introduces the design guidelines, materials selection, characterization methodology, manufacturing technology, and future potential of EMI shielding. It covers an array of issues in advanced shielding materials and design solutions, including enclosures and composites.

  17. Layered shielding design for an active neutron interrogation system

    Science.gov (United States)

    Whetstone, Zachary D.; Kearfott, Kimberlee J.

    2016-08-01

    The use of source and detector shields in active neutron interrogation can improve detector signal. In simulations, a shielded detector with a source rotated π/3 rad relative to the opening decreased neutron flux roughly three orders of magnitude. Several realistic source and detector shield configurations were simulated. A layered design reduced neutron and secondary photon flux in the detector by approximately one order of magnitude for a deuterium-tritium source. The shield arrangement can be adapted for a portable, modular design.

  18. Fusion reactor blanket/shield design study

    International Nuclear Information System (INIS)

    A joint study of tokamak reactor first-wall/blanket/shield technology was conducted by Argonne National Laboratory (ANL) and McDonnell Douglas Astronautics Company (MDAC). The objectives of this program were the identification of key technological limitations for various tritium-breeding-blanket design concepts, establishment of a basis for assessment and comparison of the design features of each concept, and development of optimized blanket designs. The approach used involved a review of previously proposed blanket designs, analysis of critical technological problems and design features associated with each of the blanket concepts, and a detailed evaluation of the most tractable design concepts. Tritium-breeding-blanket concepts were evaluated according to the proposed coolant. The ANL effort concentrated on evaluation of lithium- and water-cooled blanket designs while the MDAC effort focused on helium- and molten salt-cooled designs. A joint effort was undertaken to provide a consistent set of materials property data used for analysis of all blanket concepts. Generalized nuclear analysis of the tritium breeding performance, an analysis of tritium breeding requirements, and a first-wall stress analysis were conducted as part of the study. The impact of coolant selection on the mechanical design of a tokamak reactor was evaluated. Reference blanket designs utilizing the four candidate coolants are presented

  19. Radiation shielding analysis for conceptual design of HIC transport package

    International Nuclear Information System (INIS)

    KHNP(Korea Hydro and Nuclear Power Ltd., Co.) is developing a HIC transport package which is satisfying domestic and IAEA regulations and NETEC(Nuclear Environment Technology Institute) is conducting a conceptual design. In this study, the shielding thickness was calculated using the data from radionuclide assay program which is currently using in nuclear sites and Micro Shield code. Considering the structural safety, carbon steel was chosen as shielding material and the shielding thickness was calculated for 500 R/hr and 100 R/hr at HIC surface, respectively. Through the shielding analysis, it was evaluated that the regulation limit is satisfied when the shielding thickness is 22 cm for 500 R/hr and 17 cm for 100/hr

  20. Optimized Design of the Shielded-Loop Resonator

    DEFF Research Database (Denmark)

    Stensgaard, Anders

    1996-01-01

    The shielded-loop resonator is known to have low capacitive sample loss due to perfect balancing. We present a new analysis of the unbalanced driven shielded-loop resonator that calculates the resonance frequencies and also determines some design considerations. The analysis enables us to optimize...

  1. Design of ITER vacuum vessel in-wall shielding

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X., E-mail: xiaoyu.wang@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Ioki, K. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Morimoto, M. [Mitsubishi Heavy Industries, 1-1, Wadasaki-cho 1-chome, Hyogo-ku, Kobe (Japan); Choi, C.H.; Utin, Y.; Sborchia, C. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); TaiLhardat, O. [Assystem EOS, ZAC SAINT MARTIN, 23 rue Benjamin Franklin, 84120 Pertuis (France); Mille, B.; Terasawa, A.; Gribov, Y.; Barabash, V.; Polunovskiy, E.; Dani, S. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Pathak, H.; Raval, J. [ITER-India, Institute for Plasma Research, Gandhinagar 382025 (India); Liu, S.; Lu, M.; Du, S. [Institute of Plasma Physics, China Academy of Sciences, Shushanhu Road 350, Hefei (China)

    2014-10-15

    The ITER vacuum vessel is a torus-shaped, double wall structure. The space between the double walls of the VV is filled with in-wall shielding (IWS) and cooling water. The main purpose of the in-wall shielding is to provide neutron shielding together with the blanket and VV shells and water during ITER plasma operation and to reduce the ripple of the Toroidal magnetic field. Based on ITER vacuum vessel structure and related requirements, in-wall shielding are designed as about 8900 individual blocks with different sizes and several different materials distributed over nine vessel sectors and nine field joints of vessel sectors. This paper presents the design of the IWS, considering loads, structural stresses and assembly method, and also shows neutron shielding effect and TF ripple reduced by the IWS.

  2. Planar quadrature coil design using shielded-loop resonators

    DEFF Research Database (Denmark)

    Stensgaard, A

    1997-01-01

    The shielded-loop resonator is known to have a low capacitive sample loss due to a perfect balancing. In this paper, it is demonstrated that shielded-loop technology also can be used to improve design of planar quadrature coils. Both a dual-loop circuit and especially a dual-mode circuit may...... benefit from use of shielded-loop resonators. Observations in measurements agree with theory for both a dual-loop coil and a dual-mode coil. The coils were designed for use as transmit/receive coil for 1H imaging and spectroscopy at 4.7 T in rat brain....

  3. Optimization of the National Ignition Facility primary shield design

    Energy Technology Data Exchange (ETDEWEB)

    Annese, C.E.; Watkins, E.F.; Greenspan, E.; Miller, W.F. [California Univ., Berkeley, CA (United States). Dept. of Nuclear Engineering; Latkowski, J.; Lee, J.D.; Soran, P.; Tobin, M.L. [Lawrence Livermore National Lab., CA (United States)

    1993-10-01

    Minimum cost design concepts of the primary shield for the National Ignition laser fusion experimental Facility (NIF) are searched with the help of the optimization code SWAN. The computational method developed for this search involves incorporating the time dependence of the delayed photon field within effective delayed photon production cross sections. This method enables one to address the time-dependent problem using relatively simple, time-independent transport calculations, thus significantly simplifying the design process. A novel approach was used for the identification of the optimal combination of constituents that will minimize the shield cost; it involves the generation, with SWAN, of effectiveness functions for replacing materials on an equal cost basis. The minimum cost shield design concept was found to consist of a mixture of polyethylene and low cost, low activation materials such as SiC, with boron added near the shield boundaries.

  4. Shielding design for PWR in France

    Energy Technology Data Exchange (ETDEWEB)

    Champion, G.; Charransol; Le Dieu de Ville, A.; Nimal, J.C.; Vergnaud, T.

    1983-05-01

    Shielding calculation scheme used in France for PWR is presented here for 900 MWe and 1300 MWe plants built by EDF the French utility giving electricity. Neutron dose rate at areas accessible by personnel during the reactor operation is calculated and compared with the measurements which were carried out in 900 MWe units up to now. Measurements on the first French 1300 MWe reactor are foreseen at the end of 1983.

  5. Fusion reactor design towards radwaste minimum with advanced shield material

    International Nuclear Information System (INIS)

    A new concept of fusion reactor design is proposed to minimize the radioactive waste of the reactor. The main point of the concept is to clear massive structural components located outside the neutron shield from regulatory control. The concept requires some reinforcement of shielding with an advanced shield material such as a metal hydride, detriation, and tailoring of a detrimental element from the superconductor. Our assessment confirmed a large impact of the concept on radwaste reduction, in that it reduces the radwaste fraction of a fusion reactor A-SSTR2 from 92 wt.% to 17 wt.%. (author)

  6. Gamma-ray shielding design and performance test of WASTEF

    International Nuclear Information System (INIS)

    The Waste Safety Testing Facility (WASTEF) was planned in 1978 to test the safety performance of HLW vitrified forms under the simulated conditions of long term storage and disposal, and completed in August 1981. The designed feature of the facility is to treat the vitrified forms contain actual high-level wastes of 5 x 104 Ci in maximum with 5 units of concrete shilded hot cells (3 units : Bate-Gamma cells, 2 units : Alpha-Gamma cells) and one units of Alpha-Gamma lead shielded cell, and to store radioactivity of 106 Ci in maximum. The safety performance of this facility is fundamentally maintained with confinement of radioactivity and shielding of the radiation. This report describes the method of gamma-ray shielding design, evaluation of the shielding test performed by using sealded gamma-ray sources(Co-60). (author)

  7. Shielding design calculation of a 50 MW research reactor

    International Nuclear Information System (INIS)

    The computer code ANISN/PC has been applied to calculate the group flux distribution across different shield layers of a 50 MW light water research reactor. The code has been run in P3 approximation and S8 discrete ordinates. The calculated group fluxes multiplied by appropriate flux-to-dose rate conversion factors have been used to give the dose distribution across the shield layers. The thickness of the concrete shield has been determined to give the dose rate at the outer surface of the shield as 0.5 nSv/sec. The same calculation have been also performed in axial direction to determine the thickness of water needed above the core to reduce the dose level to 25 nSv/sec. The result of calculation shows that the contribution of capture gamma rays to the total dose at the outer surface of the shield is more than 50 percent. This simplifies the calculations to determine the shield layer thickness, especially in preliminary stages of the shield design. (author)

  8. Methods for the design of shielding concrete mix ratio

    International Nuclear Information System (INIS)

    Guided by general concrete mix principles, we made a comprehensive study on methods for the design of shielding concrete mix ratio as well as its related factors by means of orthogonal design experiments and regression analysis method. Then we put forward the calculating formulae and steps for the design of shielding concrete mix ratio which combined the weight-holding method with the volume method. A series of tests and practical application show that this method of mix design is accurate, efficient and reliable. (authors)

  9. Fusion Engineering Device (FED) first wall/shield design

    International Nuclear Information System (INIS)

    The torus of the Fusion Engineering Device (FED) is comprised of the bulk shield and its associated spool lstructure and support system, the first wall water-cooled panel and armor systems, and the pumped limiter. The bulk shielding is provided by ten shield sectors that are installed in the spool structure in such a way as to permit extraction of the sectors through the openings between adjacent toroidal field coils with a direct radial movement. The first wall armor is installed on the inboard and top interior walls of these sectors, and the water-cooled panels are installed on the outboard interior walls and the pumped limiter in the bottom of the sectors. The overall design of the first wall and shield system is described in this paper

  10. Concrete mix design for X-and gamma shielding

    International Nuclear Information System (INIS)

    The design of X-ray or gamma ray radiographic exposure room requires some calculations on shielding to provide safe operation of the facility and minimum exposure to radiation workers. Careful design can lead to economical installations with minimal barriers. The design depends on such factors as: maximum energy, maximum intensity, permitted full-body dosage, workload, use factor, occupancy factor, maximum dose output and shielding materials. Choice of material for a barrier depends on convenience and cost. The radiographic exposure room is usually made of normal concrete with density of about 2.3 - 2.4 g/ cc. Normal concrete is often used for construction of exposure room because of cheap and ease of construction. This paper explained and discussed the optimum mix design for normal concrete used for X-and gamma shielding. (author)

  11. Preliminary Design and Analysis of ITER In-Wall Shielding

    Institute of Scientific and Technical Information of China (English)

    LIU Changle; YU Jie; WU Songtao; CAI Yingxiang; PAN Wanjiang

    2007-01-01

    ITER in-wall shielding (IIS) is situated between the doubled shells of the ITER Vacuum Vessel (IVV). Its main functions are applied in shielding neutron, gamma-ray and toroidal field ripple reduction. The structure of IIS has been modelled according to the IVV design criteria which has been updated by the ITER team (IT). Static analysis and thermal expansion analysis were performed for the structure. Thermal-hydraulic analysis verified the heat removal capability and resulting temperature, pressure, and velocity changes in the coolant flow. Consequently, our design work is possibly suitable as a reference for IT's updated or final design in its next step.

  12. D0 Silicon Upgrade: Muon Shield Conceptual Design Report

    International Nuclear Information System (INIS)

    The nominal overall dimensions are 71-inch high x 71-inch wide x 144-inch long and has a 25-inch square hole throughout. The shield consists of three different materials, steel (inner most section), polycarbonate (central section) and lead (outer most section). The material thicknesses are, steel=15-inch, poly=6-inch and lead=2-inch. The estimated weight is ∼69 tons. The shield is centered about the Tev beam line and the 25-inch square hole provides clearance to the low Beta quad, which is nominally 20-inch square. During beamline operation, the shield is in contact with Samus magnet core at the detector end and with the Main Ring shield wall on the MR side (with some small clearance ∼2-inch-3-inch). The need for the clearance will be discussed later. The shield support structure consists steel structural members appropriately sized for loads encountered in the design. The structure must not only support the shield but, must be designed for rolling the entire assembly into position in the collision hall. It must provide for cylinders to lift the assembly, Hilman rollers and also connections for moving the entire assembly. The movement is considered to be similar to that with which the calorimeters were moved from the clean room to the sidewalk staging area, i.e. hydraulic cylinder and chain (see dwg. 3740.000-ME294017,3 sheets). This method will be used for the East to West motion and a hydraulic scheme will be used for any North-South motion. Since the shield is 144-inch long and the sidewalk structural support is ∼96-inch, there is a section of the shield that is cantilevered (48-inch). Further, the EF toroid must open ∼40+ inch for access to the detector during operations and this requires that the shield or some part of it must also move. This conceptual design suggests that the shield be designed in two pieces axially. These two pieces are identical in cross section but, the lengths are divided into 48-inch nearest EF and 96-inch nearest the MR tunnel

  13. Shielding design for research and education reactor

    International Nuclear Information System (INIS)

    For the purpose of education and research at the University, 20-KW powered SLOWPOKE-2 research reactor has been chosen as a prototype reactor. In order to study the safety characteristics of the reactor, exposure rate has been estimated at the pool boundary. Reactor core as a radiation source is assumed to be cylindrical volume source. Thus point kernel integration method can be applied to determine the exposure rate. For the sake of simplicity, calculation was done only for the prompt fission gamma rays and fission product gamma rays. As a result, the maximum exposure rate at the pool boundary was estimated to be 18R/min at the same height of the center of the core. In order to examine the accuracy for the point kernel integration method, two shielding experiments were carried out: one for the water tank only and the other for with concrete blocks outside the water tank. Water tank was made of wood pieces which is 13.4cm wide, 1.5cm thick and 2.15m long. Thus the water tank has the total dimension of 1 m radius and 2.1 m height. The experiment was carried out for the radiation source of 0.968 mCi Co-60 at the center of the water tank and the penetrated gamma rays were measured at 5 different detector positions. For the measurement and analysis of the responses, NaI(T1) 3''x3'' detector and 256 channel multichannel analyzer was utilized. To convert pulse height distribution to the exposure rate, Moriuchi conversion factor was adopted. Data from the calculations by point kernel method were well agreed within 10% band with the data from the the experiments. (Author)

  14. On design for front shield of opening shielding%谈敞口式盾构前盾设计

    Institute of Scientific and Technical Information of China (English)

    杨泽平

    2012-01-01

    According to the use of the opening shielding in China, the paper indicates the technical features and factual implementation for the design of the front shield of the open shielding, and introduces the structural calculating methods and ideas for the main parts of the front shield of the opening shielding, so as to provide some necessary foundation for the general design of the opening shielding.%根据敞口式盾构在我国的实用情况,论述了敞口式盾构前盾设计的技术特点和具体的实施方式,介绍了敞口式盾构前盾主要部件的结构计算方法和思路,为敞口式盾构整体设计提供了必要基础。

  15. Radiation Shielding Design for ISOL System Beam Line

    Institute of Scientific and Technical Information of China (English)

    WANG; Feng; QIN; Jiu-chang

    2013-01-01

    The beam line of the ISOL system passes through the shielding wall and connects the HI-13 tandem accelerator.Neutron produced by tandem accelerator will affect the area of BRIF through the beam line.To protect the staff in BRIF area from radiation a shielding design of the beam line is carried out.The neutron source in the vault of tandem accelerator is the H.E Faraday cup of HI-13 tandem accelerator as showed in Fig.1.The Faraday cup is consisted of 1 mm molybdenum sheet and 10 mm

  16. Design and Analysis of the Thermal Shield of EAST Tokamak

    Science.gov (United States)

    Xie, Han; Liao, Ziying

    2008-04-01

    EAST (Experimental Advanced Superconducting Tokamak) is a tokamak with superconducting toroidal and poloidal magnets operated at 4.5 K. In order to reduce the thermal load applied on the surfaces of all cryogenically cooled components and keep the heat load of the cryogenic system at a minimum, a continuous radiation shield system located between the magnet system and warm components is adopted. The main loads to which the thermal shield system is subjected are gravity, seismic, electromagnetic and thermal gradients. This study employed NASTRAN and ANSYS finite element codes to analyze the stress under a spectrum of loading conditions and combinations, providing a theoretical basis for an optimization design of the structure.

  17. Design for shielding kit for local irradiation in mice and test of its shielding effect

    International Nuclear Information System (INIS)

    In order to fulfill the immediate requirement for experimental studies on biological effect of low dose radiation. A shielding kit for local irradiation in mice is designed. Its advantages are: (1) several mice can be irradiated at the same time; (2) the radiation condition is identical; (3) it is easy to control and perform; (4) during irradiation, the animals don't need any special treatments such as anaesthesia. It was proved by TLD test, that absorbed dose in areas of spleen and head in mice after shielding has decreased to 0.85% and 0.5% of the original dose in the center of radiation field respectively. The results suggest that the kit was able to satisfy the needs of the experimental studies on radiation biology

  18. Shielding of Medical Facilities. Shielding Design Considerations for PET-CT Facilities

    International Nuclear Information System (INIS)

    The radiological evaluation of a Positron Emission Tomography (PET) facility consists of the assessment of the annual effective dose both to workers occupationally exposed, and to members of the public. This assessment takes into account the radionuclides involved, the facility features, the working procedures, the expected number of patients per year, and so on. The evaluation embraces the distributions of rooms, the thickness and physical material of walls, floors and ceilings. This work detail the methodology used for making the assessment of a PET facility design taking into account only radioprotection aspects. The assessment results must be compared to the design requirements established by national regulations in order to determine whether or not, the facility complies with those requirements, both for workers and for members of the public. The analysis presented is useful for both, facility designers and regulators. In addition, some guidelines for improving the shielding design and working procedures are presented in order to help facility designer's job. (authors)

  19. Electron accelerator shielding design of KIPT neutron source facility

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Zhao Peng; Gohar, Yousry [Argonne National Laboratory, Argonne (United States)

    2016-06-15

    The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nuclear specialists. The biological shield of the accelerator building was designed to reduce the biological dose to less than 5.0e-03 mSv/h during operation. The main source of the biological dose for the accelerator building is the photons and neutrons generated from different interactions of leaked electrons from the electron gun and the accelerator sections with the surrounding components and materials. The Monte Carlo N-particle extended code (MCNPX) was used for the shielding calculations because of its capability to perform electron-, photon-, and neutron-coupled transport simulations. The photon dose was tallied using the MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is very small, ∼0.01 neutron for 100-MeV electron and even smaller for lower-energy electrons. This causes difficulties for the Monte Carlo analyses and consumes tremendous computation resources for tallying the neutron dose outside the shield boundary with an acceptable accuracy. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were utilized for this study. The generated neutrons were banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron dose. The weight windows variance reduction technique was also utilized for both neutron and photon dose

  20. Approximate design calculation methods for radiation streaming in shield irregularities

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Toshimasa; Hirao, Yoshihiro [Ship Research Inst., Mitaka, Tokyo (Japan); Yoritsune, Tsutomu

    1997-10-01

    Investigation and assessment are made for approximate design calculation methods of radiation streaming in shield irregularities. Investigation is made for (1) source, (2) definition of streaming radiation components, (3) calculation methods of streaming radiation, (4) streaming formulas for each irregularity, (5) difficulties in application of streaming formulas, etc. Furthermore, investigation is made for simple calculation codes and albedo data. As a result, it is clarified that streaming calculation formulas are not enough to cover various irregularities and their accuracy or application limit is not sufficiently clear. Accurate treatment is not made in the formulas with respect to the radiation behavior for slant incidence, bend part, offset etc., that results in too much safety factors in the design calculation and distrust of the streaming calculation. To overcome the state and improve the accuracy of the design calculation for shield irregularities, it is emphasized to assess existing formulas and develop better formulas based on systematic experimental studies. (author)

  1. Design Of Material Access Shielding Door Of ISFSF Building

    International Nuclear Information System (INIS)

    Base on the planning to maintain of the air pressure in the reactor building, the design of material access shielding door in the ISFSF building has been done. By the installation designed, the air pressure condition in the reactor building well meet the design criteria. The system requires 12 pieces of steel beam L 4 x 3 x 1/2 inches ASTM A36 and 6 pieces steel plate by 2400 x 1200 x 3 mm dimension ASTM A514. This paper concluded that this design is feasible to be realized

  2. Shielding design for the front end of the CERN SPL.

    Science.gov (United States)

    Magistris, Matteo; Silari, Marco; Vincke, Helmut

    2005-01-01

    CERN is designing a 2.2-GeV Superconducting Proton Linac (SPL) with a beam power of 4 MW, to be used for the production of a neutrino superbeam. The SPL front end will initially accelerate 2 x 10(14) negative hydrogen ions per second up to an energy of 120 MeV. The FLUKA Monte Carlo code was employed for shielding design. The proposed shielding is a combined iron-concrete structure, which also takes into consideration the required RF wave-guide ducts and access labyrinths to the machine. Two beam-loss scenarios were investigated: (1) constant beam loss of 1 Wm(-1) over the whole accelerator length and (2) full beam loss occurring at various locations. A comparison with results based on simplified approaches is also presented.

  3. Self-shielded electron linear accelerators designed for radiation technologies

    Science.gov (United States)

    Belugin, V. M.; Rozanov, N. E.; Pirozhenko, V. M.

    2009-09-01

    This paper describes self-shielded high-intensity electron linear accelerators designed for radiation technologies. The specific property of the accelerators is that they do not apply an external magnetic field; acceleration and focusing of electron beams are performed by radio-frequency fields in the accelerating structures. The main characteristics of the accelerators are high current and beam power, but also reliable operation and a long service life. To obtain these characteristics, a number of problems have been solved, including a particular optimization of the accelerator components and the application of a variety of specific means. The paper describes features of the electron beam dynamics, accelerating structure, and radio-frequency power supply. Several compact self-shielded accelerators for radiation sterilization and x-ray cargo inspection have been created. The introduced methods made it possible to obtain a high intensity of the electron beam and good performance of the accelerators.

  4. Design and analysis of electromagnetic interference filters and shields

    Science.gov (United States)

    McDowell, Andrew Joel

    Electromagnetic interference (EMI) is a problem of rising prevalence as electronic devices become increasingly ubiquitous. EMI filters are low pass filters intended to prevent the conducted electric currents and radiated electromagnetic fields of a device from interfering with the proper operation of other devices. Shielding is a method, often complementary to filtering, that typically involves enclosing a device in a conducting box in order to prevent radiated EMI. This dissertation includes three chapters related to the use of filtering and shielding for preventing electromagnetic interference. The first chapter deals with improving the high frequency EMI filtering performance of surface mount capacitors on printed circuit boards (PCBs). At high frequencies, the impedance of a capacitor is dominated by a parasitic inductance, thus leading to poor high frequency filtering performance. Other researchers have introduced the concept of parasitic inductance cancellation and have applied this concept to improving the filtering performance of volumetrically large capacitors at frequencies up to 100 MHz. The work in this chapter applies the concept of parasitic inductance cancellation to much smaller surface mount capacitors at frequencies up to several gigahertz. The second chapter introduces a much more compact design for applying parasitic inductance cancellation to surface mount capacitors that uses inductive coupling between via pairs as well as coplanar traces. This new design is suited for PCBs having three or more layers including solid ground and/or power plane(s). This design is demonstrated to be considerably more effective in filtering high frequency noise due to crosstalk than a comparable conventional shunt capacitor filter configuration. Finally, chapter 3 presents a detailed analysis of the methods that are used to decompose the measure of plane wave shielding effectiveness into measures of absorption and reflection. Textbooks on electromagnetic

  5. Design and Testing of Improved Spacesuit Shielding Components

    Energy Technology Data Exchange (ETDEWEB)

    Ware, J.; Ferl, J.; Wilson, J.W.; Clowdsley, M.S.; DeAngelis, G.; Tweed, J.; Zeitlin, C.J.

    2002-05-08

    In prior studies of the current Shuttle Spacesuit (SSA), where basic fabric lay-ups were tested for shielding capabilities, it was found that the fabric portions of the suit give far less protection than previously estimated due to porosity and non-uniformity of fabric and LCVG components. In addition, overall material transmission properties were less than optimum. A number of alternate approaches are being tested to provide more uniform coverage and to use more efficient materials. We will discuss in this paper, recent testing of new material lay-ups/configurations for possible use in future spacesuit designs.

  6. Design and Testing of Improved Spacesuit Shielding Components

    International Nuclear Information System (INIS)

    In prior studies of the current Shuttle Spacesuit (SSA), where basic fabric lay-ups were tested for shielding capabilities, it was found that the fabric portions of the suit give far less protection than previously estimated due to porosity and non-uniformity of fabric and LCVG components. In addition, overall material transmission properties were less than optimum. A number of alternate approaches are being tested to provide more uniform coverage and to use more efficient materials. We will discuss in this paper, recent testing of new material lay-ups/configurations for possible use in future spacesuit designs

  7. Design and Implementation of the HJ-1-C Satellite SAR Full-power Radiation Test

    OpenAIRE

    Zhang Hua-chun; Tao Xin; Ni Jiang; Yu Wei-dong

    2014-01-01

    In this paper, the HJ-1-C SAR full-power radiation test design is presented. For the new problems caused by SAR high-power concentrated emissions, the radar-receiving channel-leakage power test is proposed to ensure the safety of the radar-receiving path, and the transceiver channel closed-loop radar system test is discussed. The experimental results show that the proposed HJ-1-C SAR full-power radiation test scheme is reasonable and feasible, with the desired outcome.

  8. Design and Implementation of the HJ-1-C Satellite SAR Full-power Radiation Test

    Directory of Open Access Journals (Sweden)

    Zhang Hua-chun

    2014-06-01

    Full Text Available In this paper, the HJ-1-C SAR full-power radiation test design is presented. For the new problems caused by SAR high-power concentrated emissions, the radar-receiving channel-leakage power test is proposed to ensure the safety of the radar-receiving path, and the transceiver channel closed-loop radar system test is discussed. The experimental results show that the proposed HJ-1-C SAR full-power radiation test scheme is reasonable and feasible, with the desired outcome.

  9. The Load Design and Implementation of HJ-1-C Space-borne SAR

    Directory of Open Access Journals (Sweden)

    Yu Wei-dong

    2014-06-01

    Full Text Available HJ-1-C is a Synthetic Aperture Radar (SAR satellite in the Constellation of “2+1” for China environment and disaster monitoring. It works at S-band with a resolution of 5 m. SAR payload uses a reflector antenna and a high-power concentrated transmitter. Its light weight and high efficiency is very suitable for a small satellite platform. Now HJ-1-C satellite has been launched into orbit and has acquired Chinese first S-band SAR images from space, which demonstrate excellent quality and rich information about scenes imaged. This success verifies our design, testing and experiment work on the payload. With its following operation, HJ-1-C satellite is expected to make a great contribution to the applications of environment protection and disaster monitoring in China. This paper introduces the design and development of HJ-1-C SAR payload, present its main parameters and performance, describes its device details and its manufacture, testing and experiment process. Some images acquired in the orbit are showed.

  10. Structural Integrity Evaluation of Cold Neutron Laboratory Building by Design Change of Guide Shielding Room

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sangik; Kim, Youngki; Kim, Harkrho

    2007-06-15

    This report summarizes the results of the structural integrity evaluation for the cold neutron laboratory building by design change of guide shielding room. The design of the guide shielding room was changed by making its structure members in normal concrete (2.3 g/cc) instead of heavy concrete (3.5 g/cc) because the heavy concrete could be not supplied to meet its design specification. Therefore, it was decided that the guide shielding room is made of the normal concrete. And, the shielding performance of the normal concrete was recalculated to confirm satisfying its design specification, which is of a 9000 zone according to HANARO radiation region classification. The change makes the shielding wall thicker than existing design, and then it is caused to qualify the structural integrity evaluation of the CNLB. Finally, the structural integrity of the CNLB was re-evaluated by considering the design change of the guide shielding room.

  11. System Design and In-orbit Verification of the HJ-1-C SAR Satellite

    OpenAIRE

    Zhang Run-ning; Jiang Xiu-peng

    2014-01-01

    HJ-1-C is a SAR satellite owned by the Chinese Environment and Natural Disaster Monitoring constellation, and works together with the optical satellites HJ-1-A/B for monitoring environment and natural disasters. In this paper, the system design and characteristics of the first Chinese civil SAR satellite are described. In addition, the interface relation between SAR payload and platform is studied. Meanwhile, the data transmission capability, attitude, power, and temperature control that supp...

  12. Design Optimization of Expansion Driven Components for the HJ-1-C Satellite

    Directory of Open Access Journals (Sweden)

    Huang Zhi-rong

    2014-06-01

    Full Text Available Expansion-driven HJ-1-C satellite components are prone to fatigue and fracture; thus, a reliability study on the optimal design is performed. According to the Failure Mode and Effects Analysis (FMEA of the components, the main failure modes are stress relaxation and impact breakage of the torsion and scroll springs. On the basis of the failure modes, a prototype spring is tested, and the relative reliabilities are calculated. Then, reliability measures are proposed, and the design optimization of the springs is carried out. The improvements introduced by the prototype spring are indicative of the effectiveness and reliability of the design optimization process, which can help design and analyze similar antenna reflectors in the future.

  13. Neutron beam-line shield design for the protein crystallography instrument at the Lujan Center

    International Nuclear Information System (INIS)

    We have developed a very useful methodology for calculating absolute total (neutron plus gamma-ray) dose equivalent rates for use in the design of neutron beam line shields at a spallation neutron source. We have applied this technique to the design of beam line shields for several new materials science instruments being built at the Manuel Lujan Jr. Neutron Scattering Center. These instruments have a variety of collimation systems and different beam line shielding issues. We show here some specific beam line shield designs for the Protein Crystallography Instrument. (author)

  14. Design and Implementation of Simultaneous Shield And Repeater Insertion for On-chip Interconnects

    Directory of Open Access Journals (Sweden)

    M. Surendra Goud Mr. Y. Sreenivas Goud

    2012-02-01

    Full Text Available A Resource based optimization is a new approach for high performance integrated circuits. The method is applied to simultaneous shield and repeater insertion, resulting in minimum coupling noise under power, delay, and area constraints Repeater insertion is a well known design technique to reduce the delay required to propagate a signal along a line. Shielding inserts an additional line between a victim line and an aggressor line. Finally placing a shield beside and inserting repeaters along a victim line and are chosen to exemplify the resource based optimization process. In the active shielding architecture shield driving circuits as 4:1 multiplexer, full adder, multipliers are inserted. The power consumption of active shielding architecture is observed to be approximately 20% less compare to passive shielding architecture. The main aim of this is minimize the coupling noise under power, delay, and area constraints

  15. System Design and In-orbit Verification of the HJ-1-C SAR Satellite

    Directory of Open Access Journals (Sweden)

    Zhang Run-ning

    2014-06-01

    Full Text Available HJ-1-C is a SAR satellite owned by the Chinese Environment and Natural Disaster Monitoring constellation, and works together with the optical satellites HJ-1-A/B for monitoring environment and natural disasters. In this paper, the system design and characteristics of the first Chinese civil SAR satellite are described. In addition, the interface relation between SAR payload and platform is studied. Meanwhile, the data transmission capability, attitude, power, and temperature control that support SAR imaging are reviewed. Finally, the corresponding in-orbit verification results are presented.

  16. Shielding design calculations for ESS activated target system

    International Nuclear Information System (INIS)

    Full text of publication follows: The European Spallation Source (ESS) is a European common effort in designing and building a next generation large-scale user facility for studies of the structure and dynamics of materials. The ESS target, moderators and reflectors system through interactions with 5 MW proton beam (2.5 GeV, 20 Hz) will produce long pulse (2.8 ms width) neutrons in sub-thermal and thermal energy range. These neutrons are further transported to a variety of neutron scattering instruments. The aim of this work is to assess the strategy to be used for the safe handling and shipping of the ESS target and associated shaft. For safe maintenance, during operation as well as handling, transport and storage of the components of the ESS target station after their lifetime, detailed knowledge is required about the activation induced by the impinging protons and secondary radiation fields. The Monte Carlo transport code MCNPX2.6.0 was coupled with CINDER90 version 07.4 to calculate the residual nuclide production in the target wheel and associated shaft. Dose equivalent rates due to the residual radiation were further calculated with the MICROSHIELD and MCNPX codes using photon sources resulting from CINDER. Various decay times after ceasing operation of the target components were considered. The activation and decay heat density distributions of the target system together with the derived dose rates were analysed to assess the best strategy to be used for their safe removal and transport to a hot cell, eventual dismantling, storage on-site and shipping off-site as intermediate level waste packages. The derived photon sources were used afterwards to design the shielded exchange flasks that are needed to remove and transport the target after its lifespan to a hot cell. Design of a multipurpose cask able to accommodate the different highly activated components of the ESS target station and ship them to external conditioning facility is intended to be developed

  17. Shielding analyses for design of the upgraded JRR-3 research reactor, 1

    International Nuclear Information System (INIS)

    Shielding analyses for design of the upgraded JRR-3 research reactor have been performed. In the report described are the design principles and the overall analytical procedures. In addition, described are the results of shielding analyses of reactor, canal, spent fuel storage pond and so on. (author)

  18. Simbol-X Mirror Module Thermal Shields: I - Design and X-Ray Transmission

    International Nuclear Information System (INIS)

    The Simbol-X mission is designed to fly in formation flight configuration. As a consequence, the telescope has both ends open to space, and thermal shielding at telescope entrance and exit is required to maintain temperature uniformity throughout the mirrors. Both mesh and meshless solutions are presently under study for the shields. We discuss the design and the X-ray transmission.

  19. Design and optimization of HPLWR high pressure Turbine gamma ray shield

    International Nuclear Information System (INIS)

    Highlights: • Shield around HPLWR high pressure turbine optimized by Monte Carlo method. • The occupancy period in the turbine building was considered in the optimization. • Shield thickness is significantly reduced when heavy concretes are used. • Shield thickness for BWRs is sufficient for HPWR if heavy concrete is used. - Abstract: This work proposes the optimum gamma ray shield thickness around the HPLWR high pressure turbine for different occupancy periods in the turbine building. Monte Carlo method was employed in the design process and only radioactive nitrogen-16 was considered as the source of radiation. Five grades of concrete (ordinary, magnetite, heavy magnetite, steel magnetite and barite) were used as shielding materials. The isotope source term in the high pressure turbine was estimated by modeling the HPLWR three pass core in MCNP and tracking the inventory using a simple algorithm. The high pressure turbine was thereafter modeled in MCNP with a concrete shield arrayed in layers around it. The surface flux tally and ICRP74 dose conversion coefficients were employed to estimate the dose profile across the shield. For some shielding materials, exponential functions were fitted on the calculated data to extrapolate dose values beyond the model thickness. The optimum shield thickness was determined by comparing the calculated dose profiles with dose limit proposals in the IAEA standard (NS-G-1.13) on radiation protection considerations during nuclear power plant design. It was observed that with a 120 cm thick heavy concrete shield, the turbine building would be safe for most occupancy periods. However for ordinary concrete the shield would require some extension to guarantee safety. For very long occupancy (more than 10 person hours per week), magnetite shield may also require slight extension. It can therefore be concluded that the shield thickness recommended for BWR turbines (which operate on a direct cycle like HPLWR) could be sufficient

  20. Application of Particle Swarm Optimization Algorithm in Design of Multilayered Planar Shielding Body

    Institute of Scientific and Technical Information of China (English)

    FUJiwei; HOUChaozhen; DOULihua

    2005-01-01

    Based on the basic electromagnetic wave propagation theory in this article, the Particle swarm optimization algorithm (PSO) is used in the design of the multilayered composite materials and the thickness of shielding body by the existent multilayered planar composite elec-tromagnetic shielding materials model, the different shielding materials of each layer can be designed under some kinds of circumstances: the prespecified Shielding effectiveness (SE), different incident angle and the prespecified band of frequencies. Finally the algorithm is simulated. At the same time the similar procedure can be implemented by Genetic algorithm (GA). The results acquired by particle swarm optimization algorithm are compared with there sults acquired by the genetic algorithm. The results indicate that: the particle swarm optimization algorithm is much better than the genetic algorithm not only in convergence speed but also in simplicity. So a more effective method (Particle Swarm Optimization algorithm) is offered for the design of the multilayered composite shielding materials.

  1. Magnetic Field Design by Using Image Effect from Iron Shield

    Institute of Scientific and Technical Information of China (English)

    Quanling PENG; S.M. McMurry; J.M.D.Coey

    2004-01-01

    Permanent magnet rings are presented, which exploit the image effect in the surrounding circular iron shields. The theory is given for a general permanent ring when the magnetization orientation Ψ at each coordinate angle Ψ changes by Ψ=(n+1)Ψ,where n is a positive or negative integer. For the uniformly magnetized case n=-1, the permanent ring produces no field in its bore, and the field is that of a dipole outside. When the ring is surrounded by a soft iron shield, its field becomes uniform in the bore, and zero outside the ring. The field can be varied continuously by moving the iron shield along the magnet axis.A small variable field device was constructed by using NdFeB permanent rings, which produced a field flux density of 0~0.5 T in the central region.

  2. Effect of compositional variation in plutonium on process shielding design

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.H.

    1997-11-01

    Radiation dose rate from plutonium with high {sup 239}Pu content varies with initial nuclidic content, radioactive decay time, and impurity elemental content. The two idealized states of old plutonium and clean plutonium, whose initial compositions are given, provide approximate upper and lower bounds on dose rate variation. Whole-body dose rates were calculated for the two composition states, using unshielded and shielded plutonium spheres of varying density. The dose rates from these variable density spheres are similar to those from expanded plutonium configurations encountered during processing. The dose location of 40 cm from the sphere center is representative of operator standoff for direct handling of plutonium inside a glove box. The results have shielding implications for glove boxes with only structurally inherent shielding, especially for processing of old plutonium in an expanded configuration. Further reduction in total dose rate by using lead to reduce photon dose rate is shown for two density cases representing compact and expanded plutonium configurations.

  3. Shielding design of a mobile electron accelerator using Monte Carlo technique

    International Nuclear Information System (INIS)

    Shielding of a mobile electron accelerator of 0.6 MeV, 33 mA has been designed and examined by Monte Carlo technique. Based on a 3-D model of electron accelerator shielding which is designed with steel and lead shield, radiation leakage was examined using the MCNP code. Calculations using two different versions (version 4C2 and version 5) of MCNP showed agreements within statistical uncertainties, and the highest leakage expected is 5.5061 x 10-1 (1 ± 0.0454) μSvh-1, which is far below the tolerable radiation dose limit of 1 mSv (week)-1

  4. Design of the shield door and transporter for the Culham Conceptual Tokamak Reactor Mark II

    International Nuclear Information System (INIS)

    In the Culham Conceptual Tokamak Reactor MK II access to the interior for blanket maintenance is through large openings in the fixed shield structure closed by removable shield doors when the reactor is operational. This report describes the design of the 200 tonne doors and the associated special-purpose remote operating transporter manipulator. The design, which has not been optimised, generally uses available commercial equipment and state-of-the-art techniques. (U.K.)

  5. Final focus shielding designs for modern heavy-ion fusion power plant designs

    Science.gov (United States)

    Latkowski, J. F.; Meier, W. R.

    2001-05-01

    Recent work in heavy-ion fusion accelerators and final focusing systems shows a trend towards less current per beam, and thus, a greater number of beams. Final focusing magnets are susceptible to nuclear heating, radiation damage, and neutron activation. The trend towards more beams, however, means that there can be less shielding for each magnet. Excessive levels of nuclear heating may lead to magnet quench or to an intolerable recirculating power for magnet cooling. High levels of radiation damage may result in short magnet lifetimes and low reliability. Finally, neutron activation of the magnet components may lead to difficulties in maintenance, recycling, and waste disposal. The present work expands upon previous, three-dimensional magnet shielding calculations for a modified version of the HYLIFE-II IFE power plant design. We present key magnet results as a function of the number of beams.

  6. Final Focus Shielding Designs for Modern Heavy-Ion Fusion Power Plant Designs

    Energy Technology Data Exchange (ETDEWEB)

    Latkowski, J F; Meier, W R

    2000-07-05

    Recent work in heavy-ion fusion accelerators and final focusing systems shows a trend towards less current per beam, and thus, a greater number of beams. Final focusing magnets are susceptible to nuclear heating, radiation damage, and neutron activation. The trend towards more beams, however, means that there can be less shielding for each magnet, Excessive levels of nuclear heating may lead to magnet quench or an intolerable recirculating power for magnet cooling. High levels of radiation damage may result in short magnet lifetimes and low reliability. Finally, neutron activation of the magnet components may lead to difficulties in maintenance, recycling, and waste disposal. The present work expands upon previous, three-dimensional magnet shielding calculations for a modified version of the HYLIFE-I1 IFE power plant design. We present key magnet results as a function of the number of beams.

  7. Design improvement for reduction of decommissioning waste of PWR primary biological shield

    International Nuclear Information System (INIS)

    Most operating nuclear power plants were constructed with no attention to the amount of decommissioning waste. Consequently, a large portion of the primary concrete shield wall is irradiated by neutrons escaping from the reactor core to produce high concentration of activation products. These radioactive waste comprises of around 30% of the decommissioning waste. Under the circumstance that the rad waste disposal cost is continuously increasing, reduction of decommissioning waste becomes an important issue. In this study, a design improvement was attempted to reduce activation of the primary shield wall by placing a water-filled neutron shield tank between the reactor pressure vessel and the primary shield wall. Procedure for calculating the amount of activated radionuclides remaining at different cooling times were developed by MCNP-ORIGEN coupled calculations. Particular attention was paid to correction of activation cross sections since the ORIGEN code was designed for use in calculation of isotope generation and depletion in the operating reactor core where temperature is high, while temperature of the shield wall is low. The established procedure was applied to the 1500MWe APR+ model to evaluated the effectiveness of the neutron shield tank. Distributions of activation products for many different thickness of the neutron shield tank were calculated and an effective thickness was selected. Finally, by comparing the resulting activity distributions with the exemption criteria for radioactive waste, the expected cost reduction was assessed. The model applied in this study, however, is limited to preliminary design in terms of neutronics and does not take account any engineering problems which may be caused by installation of the shield tank. Practical engineering needs further detailed design analysis including cooling and cleaning of the shield water and other related engineering issues

  8. Myo1c is designed for the adaptation response in the inner ear

    OpenAIRE

    Batters, Christopher; Arthur, Christopher P.; Lin, Abel; Porter, Jessica; Geeves, Michael A.; Milligan, Ronald A.; Molloy, Justin E.; Coluccio, Lynne M.

    2004-01-01

    The molecular motor, Myo1c, a member of the myosin family, is widely expressed in vertebrate tissues. Its presence at strategic places in the stereocilia of the hair cells in the inner ear and studies using transgenic mice expressing a mutant Myo1c that can be selectively inhibited implicate it as the mediator of slow adaptation of mechanoelectrical transduction, which is required for balance. Here, we have studied the structural, mechanical and biochemical properties of Myo1c to gain an insi...

  9. REPOSITORY LAYOUT SUPPORTING DESIGN FEATURE #13- WASTE PACKAGE SELF SHIELDING

    Energy Technology Data Exchange (ETDEWEB)

    J. Owen

    1999-04-09

    The objective of this analysis is to develop a repository layout, for Feature No. 13, that will accommodate self-shielding waste packages (WP) with an areal mass loading of 25 metric tons of uranium per acre (MTU/acre). The scope of this analysis includes determination of the number of emplacement drifts, amount of emplacement drift excavation required, and a preliminary layout for illustrative purposes.

  10. Shielding design of electron beam accelerators using supercomputer

    International Nuclear Information System (INIS)

    The MCNP5 neutron, electron, photon Monte Carlo transport program was installed on the KISTI's SUN Tachyon computer using the parallel programming. Electron beam accelerators were modeled and shielding calculations were performed in order to investigate the reduction of computation time in the supercomputer environment. It was observed that a speedup of 40 to 80 of computation time can be obtained using 64 CPUs compared to an IBM PC

  11. The Load Design and Implementation of HJ-1-C Space-borne SAR

    OpenAIRE

    Yu Wei-dong; Yang Ru-liang; Deng Yun-kai; Zhao Feng-jun; Lei Hong

    2014-01-01

    HJ-1-C is a Synthetic Aperture Radar (SAR) satellite in the Constellation of “2+1” for China environment and disaster monitoring. It works at S-band with a resolution of 5 m. SAR payload uses a reflector antenna and a high-power concentrated transmitter. Its light weight and high efficiency is very suitable for a small satellite platform. Now HJ-1-C satellite has been launched into orbit and has acquired Chinese first S-band SAR images from space, which demonstrate excellent quality and rich ...

  12. Design, fabrication and test of Load Bearing multilayer insulation to support a broad area cooled shield

    Science.gov (United States)

    Dye, S. A.; Johnson, W. L.; Plachta, D. W.; Mills, G. L.; Buchanan, L.; Kopelove, A. B.

    2014-11-01

    Improvements in cryogenic propellant storage are needed to achieve reduced or Zero Boil Off of cryopropellants, critical for long duration missions. Techniques for reducing heat leak into cryotanks include using passive multi-layer insulation (MLI) and vapor cooled or actively cooled thermal shields. Large scale shields cannot be supported by tank structural supports without heat leak through the supports. Traditional MLI also cannot support shield structural loads, and separate shield support mechanisms add significant heat leak. Quest Thermal Group and Ball Aerospace, with NASA SBIR support, have developed a novel Load Bearing multi-layer insulation (LBMLI) capable of self-supporting thermal shields and providing high thermal performance. We report on the development of LBMLI, including design, modeling and analysis, structural testing via vibe and acoustic loading, calorimeter thermal testing, and Reduced Boil-Off (RBO) testing on NASA large scale cryotanks. LBMLI uses the strength of discrete polymer spacers to control interlayer spacing and support the external load of an actively cooled shield and external MLI. Structural testing at NASA Marshall was performed to beyond maximum launch profiles without failure. LBMLI coupons were thermally tested on calorimeters, with superior performance to traditional MLI on a per layer basis. Thermal and structural tests were performed with LBMLI supporting an actively cooled shield, and comparisons are made to the performance of traditional MLI and thermal shield supports. LBMLI provided a 51% reduction in heat leak per layer over a previously tested traditional MLI with tank standoffs, a 38% reduction in mass, and was advanced to TRL5. Active thermal control using LBMLI and a broad area cooled shield offers significant advantages in total system heat flux, mass and structural robustness for future Reduced Boil-Off and Zero Boil-Off cryogenic missions with durations over a few weeks.

  13. Design and Test of a Blast Shield for Boeing 737 Overhead Compartment

    Directory of Open Access Journals (Sweden)

    Xinglai Dang

    2006-01-01

    Full Text Available This work demonstrates the feasibility of using a composite blast shield for hardening an overhead bin compartment of a commercial aircraft. If a small amount of explosive escapes detection and is brought onboard and stowed in an overhead bin compartment of a passenger aircraft, the current bins provide no protection against a blast inside the compartment. A blast from the overhead bin will certainly damage the fuselage and likely lead to catastrophic inflight structural failure. The feasibility of using an inner blast shield to harden the overhead bin compartment of a Boeing 737 aircraft to protect the fuselage skin in such a threat scenario has been demonstrated using field tests. The blast shield was constructed with composite material based on the unibody concept. The design was carried out using LS-DYNA finite element model simulations. Material panels were first designed to pass the FAA shock holing and fire tests. The finite element model included the full coupling of the overhead bin with the fuselage structure accounting for all the different structural connections. A large number of iterative simulations were carried out to optimize the fiber stacking sequence and shield thickness to minimize weight and achieve the design criterion. Three designs, the basic, thick, and thin shields, were field-tested using a frontal fuselage section of the Boeing 737–100 aircraft. The basic and thick shields protected the integrity of the fuselage skin with no skin crack. This work provides very encouraging results and useful data for optimization implementation of the blast shield design for hardening overhead compartments against the threat of small explosives.

  14. Design of portable radiation-shielding device for gamma radiography of pipe welds

    International Nuclear Information System (INIS)

    Industrial radiography is a nondestructive test method that makes use of ionizing radiation, requiring the adoption of adequate radiation safety measures. Radiation protection systems adopted for industrial radiography operations must take into account radiological workers as well as members of the public. The importance of this concern increases in construction sites, oil refineries, process plants and offshore installations. In such cases, industrial radiography of several thousand welded joints may be required while members of the public are working in other construction activities nearby. An analysis was performed on radiation safety standards adopted in industrial radiography operations in construction sites. Following a critical review, performance specifications were developed for a portable radiation-shielding device to be used in gamma radiography of pipe welds. Prototypes were designed, built and tested under actual construction site conditions, performing successfully. The radiation-shielding devices were developed to fit specific pipe sizes. A support system is designed to clamp to the pipe joint under examination. A collimator and a shield are permanently attached to this support system, according to optimum geometric arrangements of source, weld and film, intended to improve radiographic quality and to reduce setup and exposure times. The special-purpose collimator is penetrated by the isotope source, shielding radiation in all directions, except for the solid angle corresponding to the film. The shield, placed behind the film, covers that solid angle, ensuring that radiation is properly shielded in all directions. (author)

  15. Present status and future needs of nuclear data for high energy accelerator shielding design calculation

    International Nuclear Information System (INIS)

    With increasing application of high energy accelerators, their shielding design study has become very important. The present study discusses the current status of nuclear data, especially inclusive neutron production cross sections (thin target yields), thick target yields, neutron transmission through shield and cross sections, and activation and spallation cross sections of neutrons and protons. Their experimental and theoretical data are compared and further needs of basic nuclear data for shielding design calculation are described. Nuclear data in high energy regions above 20 MeV, such as double differential neutron production cross section, double differential neutron yield and neutron reaction cross section, are very poor both in number and in accuracy at the present stage. The shielding design calculation requires the comprehensive data set of these cross sections and/or the more accurate computer code to calculate these quantities. Further effort is expected to carry out shielding and cross section experiments using the monoenergetic neutron beam line which is under construction in Takasaki Branch of JAERI (Japan Atomic Energy Research Institute). (N.K.)

  16. Methodology for performing the design review of plant shielding and environmental qualification required after TMI-2

    International Nuclear Information System (INIS)

    After TMI-2, the NRC issued several documents requiring a design review of plant shielding and environmental qualification for spaces/systems which may be used in post-accident operations. The objective of this requirement was to confirm the shielding provided around systems that may contain highly radioactive materials as a result of an accident, which may unduly limit personnel occupancy or degrade safety equipment by radiation. The objective of this paper is to describe a methodology developed to obtain the inputs needed for shielding and dose calculations. It has to be pointed out that criteria for determination of vital areas, system flow paths and fluid data were not well defined by the NRC and the events considered were beyond design basis. The paper described (1) the approach adopted, exposing the conservative hypothesis applied to meet the intention of requirements, (2) more significant differences in this job between PWR and BWR, and (3) some complementary applications of the work developed

  17. Design concepts to minimize the activation of the biological shield of light-water reactors

    International Nuclear Information System (INIS)

    An investigation, concentrating on the nuclear aspects, has been made into the concept of minimizing the activation of the biological shield by substituting the material concrete with other neutron-shielding materials. This work was for nuclear plant designs which have a non-supporting inner shield wall such as that in the General Electric BWR/6 and the Kraftwerk Union PWR. The attenuation performance and activation levels have been analysed. Based on this analysis the performance of the materials in relation to that of concrete was assessed. Other non-nuclear properties were considered but the engineering problems were not addressed. The conclusion reached was that the concept was credible but would require a more rigorous examination in terms of structural design, economics and licensability

  18. Design of shielded encircling send-receive type pulsed eddy current probe using numerical analysis method

    International Nuclear Information System (INIS)

    An encircling send-receive type pulsed eddy current (PEC) probe is designed for use in aluminum tube inspection. When bare receive coils located away from the exciter were used, the peak time of the signal did not change although the distance from the exciter increased. This is because the magnetic flux from the exciter coil directly affects the receive coil signal. Therefore, in this work, both the exciter and the sensor coils were shielded in order to reduce the influence of direct flux from the exciter coil. Numerical simulation with the designed shielded encircling PEC probe showed the corresponding increase of the peak time as the sensor distance increased. Ferrite and carbon steel shields were compared and results of the ferrite shielding showed a slightly stronger peak value and a quicker peak time than those of the carbon steel shielding. Simulation results showed that the peak value increased as the defect size (such as depth and length) increased regardless of the sensor location. To decide a proper sensor location, the sensitivity of the peak value to defect size variation was investigated and found that the normalized peak value was more sensitive to defect size variation when the sensor was located closer to the exciter.

  19. Evaluation of Demo 1C composite flywheel rotor burst test and containment design

    Energy Technology Data Exchange (ETDEWEB)

    Kass, M.D.; McKeever, J.W.; Akerman, M.A.; Goranson, P.L.; Litherland, P.S.; O`Kain, D.U.

    1998-07-01

    Laboratory-Directed funds were provided in FY 1995 for research to develop flywheel containment specifications and to consider concepts that could satisfy these specifications and produce a prototype small, lightweight, inexpensive, mobile flywheel containment. Research activities have included an analytical and pictorial review of the Demo 1C flywheel failure test, which provided significant insight about radial and axial failure modes; calculations of the thickness of ultra-conservative pressure vessel containment; entertainment of advanced containment concepts using lightweight materials and armor literature; consideration of fabrication assembly procedures; and participation in a Flywheel Energy Storage Workshop during which additional flywheel failure experiences were discussed. Based on these activities, calculations, and results, a list of conclusions concerning flywheel containment and its relation to the flywheel are presented followed by recommendations for further research.

  20. Guide to beamline radiation shielding design at the Advanced Photon Source

    International Nuclear Information System (INIS)

    This document is concerned with the general requirements for radiation shielding common to most Advanced Photon Source (APS) users. These include shielding specifications for hutches, transport, stops, and shutters for both white and monochromatic beams. For brevity, only the results of calculations are given in most cases. So-called open-quotes special situationsclose quotes are not covered. These include beamlines with white beam mirrors for low-pass energy filters (open-quotes pink beamsclose quotes), extremely wide band-pass monochromators (multilayers), or novel insertion devices. These topics are dependent on beamline layout and, as such, are not easily generalized. Also, many examples are given for open-quotes typicalclose quotes hutches or other beamline components. If a user has components that differ greatly from those described, particular care should be taken in following these guidelines. Users with questions on specific special situations should address them to the APS User Technical Interface. Also, this document does not cover specifics on hutch, transport, shutter, and stop designs. Issues such as how to join hutch panels, floor-wall interfaces, cable feed-throughs, and how to integrate shielding into transport are covered in the APS Beamline Standard Components Handbook. It is a open-quotes living documentclose quotes and as such reflects the improvements in component design that are ongoing. This document has the following content. First, the design criteria will be given. This includes descriptions of some of the pertinent DOE regulations and policies, as well as brief discussions of abnormal situations, interlocks, local shielding, and storage ring parameters. Then, the various sources of radiation on the experimental floor are discussed, and the methods used to calculate the shielding are explained (along with some sample calculations). Finally, the shielding recommendations for different situations are given and discussed

  1. Analysis of the ORNL/TSF GCFR Grid-Plate Shield Design Confirmation Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Slater, C.O.; Cramer, S.N.; Ingersoll, D.T.

    1979-08-01

    The results of the analysis of the GCFR Grid-Plate Shield Design Confirmation Experiment are presented. The experiment, performed at the ORNL Tower Shielding Facility, was designed to test the adequacy of methods and data used in the analysis of the GCFR design. In particular, the experiment tested the adequacy of methods to calculate: (1) axial neutron streaming in the GCFR core and axial blanket, (2) the amount and location of the maximum fast-neutron exposure to the grid plate, and (3) the neutron source leaving the top of the grid plate and entering the upper plenum. Other objectives of the experiment were to verify the grid-plate shielding effectiveness and to assess the effects of fuel-pin and subassembly spacing on radiation levels in the GCFR. The experimental mockups contained regions representing the GCFR core/blanket region, the grid-plate shield section, and the grid plate. Most core design options were covered by allowing: (1) three different spacings between fuel subassemblies, (2) two different void fractions within a subassembly by variation of the number of fuel pins, and (3) a mockup of a control-rod channel.

  2. Design and construction of a movement mechanical system for a shield detector of a neutron diffractometer

    International Nuclear Information System (INIS)

    We present the design parameters of the mechanical system for a shield movement detector of a neutron diffractometer and the calculations to determine the power required to produce the rotation. The movement of the detection system is an essential part in order to get neutron diffraction spectra of a crystal. (author)

  3. Analysis of the ORNL/TSF GCFR Grid-Plate Shield Design Confirmation Experiment

    International Nuclear Information System (INIS)

    The results of the analysis of the GCFR Grid-Plate Shield Design Confirmation Experiment are presented. The experiment, performed at the ORNL Tower Shielding Facility, was designed to test the adequacy of methods and data used in the analysis of the GCFR design. In particular, the experiment tested the adequacy of methods to calculate: (1) axial neutron streaming in the GCFR core and axial blanket, (2) the amount and location of the maximum fast-neutron exposure to the grid plate, and (3) the neutron source leaving the top of the grid plate and entering the upper plenum. Other objectives of the experiment were to verify the grid-plate shielding effectiveness and to assess the effects of fuel-pin and subassembly spacing on radiation levels in the GCFR. The experimental mockups contained regions representing the GCFR core/blanket region, the grid-plate shield section, and the grid plate. Most core design options were covered by allowing: (1) three different spacings between fuel subassemblies, (2) two different void fractions within a subassembly by variation of the number of fuel pins, and (3) a mockup of a control-rod channel

  4. Evaluation of the shielding design around the reactor core in the prototype FBR Monju

    Energy Technology Data Exchange (ETDEWEB)

    Shiraki, Takako; Tada, Keiko [Advanced Reactor Technology Co., Ltd., Tokyo (Japan); Usami, Shin; Sasaki, Kenji [Japan Nuclear Cycle Development Institute, Tsuruga, Fukui (Japan); Tabayashi, Masao [Japan Atomic Power Co., Tokyo (Japan)

    2000-03-01

    This paper describes shielding evaluation of the measurements around the reactor core of Monju. The measurements were performed during the system start-up tests at different power levels between 0% and 45%. The measured reaction rates have been obtained radially from the core to the in-vessel storage rack and axially to the reactor vessel upper plenum. The measured values (E) were compared with the calculated values (C) obtained with the FBR shielding analysis methods. Based upon these results, the design margins around the reactor core have been re-examined and re-confirmed. (author)

  5. Design, fabrication and testing results of vacuum vessel, thermal shield and cryostat of EAST

    International Nuclear Information System (INIS)

    The EAST (Experimental Advanced Superconducting Tokamak) is an advanced steady-state plasma physics experimental device, which has been approved by the Chinese government and being constructed as the Chinese national nuclear fusion Research project. The vacuum vessel as one of the key components for this device can provide ultra-high vacuum and cleanly location of plasma operation. It is a torus with 'D' shaped cross-section, double wall, upper vertical ports, lower vertical ports, horizontal ports and flexible supports. The cryostat is a large single walled vessel surrounding the entire basic machine with central cylindrical section and two end enclosures, a flat base structure with external reinforcements and dome-shaped lid structure. It provides the thermal barrier with the base pressure of 5x10-4 Pa between the ambient temperature testing hall and the liquid helium cooled superconducting magnet. The thermal shields comprise the vacuum vessel thermal shield (VVTS), between the vacuum vessel and the cold Toroidal Field (TF) coil structures, the cryostat thermal shield (CTS), covering the walls of the cryostat, thereby preventing direct line of sight of the room temperature walls to the cold structures, the vacuum port thermal shields (VPTS) that enclose the port connection ducts. This paper is a report of the structure design and stress analyses for the vacuum vessel, thermal shield and cryostat. And also some key R and D and testing results for these components have been presented. (author)

  6. Shielding experiments

    International Nuclear Information System (INIS)

    Shielding mock-up experiments for Prototype Fast Breeder Reactor (PFBR) and Advanced Heavy Water Reactor (AHWR) are carried out in shielding corner facility of APSARA reactor, to assess the overall accuracy of the codes and nuclear data used in reactor shield design. As APSARA is a swimming pool-type thermal reactor, for fast reactor experiments, typical fast reactor shielding facility was created by using uranium assemblies as spectrum converter. The flux was also enhanced by replacing water by air. Experiments have been carried out to study neutron attenuation through typical fast reactor radial and axial bulk shielding materials such as steel, sodium, graphite, borated graphite and boron carbide. A large number of reaction rates, sensitive to different regions of the neutron energy spectrum, were measured using foil activation and Solid State Nuclear Track Detector (SSNTD) techniques. These experimental results were analysed using computational tools normally used in design calculations, viz., discrete ordinate transport codes with multigroup cross section sets. Comparison of measured reaction rates with calculations provided suitable bias factors for parameters relevant to shield design, such as sodium activation, fast neutron fluence, fission equivalent fluxes etc. The measured neutron spectrum on the incident face of shield model compares well with the calculated fast reactor blanket leakage neutron spectrum. The comparison of calculated reaction rates within shield model indicate that the calculations suffer from considerable uncertainties, in shield models with boron carbide/borated graphite. For AHWR shielding experiments, no spectrum converter was used as it is also a thermal reactor. Radiation streaming studies through penetrations/ducts of various shapes and sizes relevant to AHWR shielding were carried out. (author)

  7. Shielding analysis and design of the KIPT experimental neutron source facility of Ukraine.

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Z.; Gohar, M. Y. A.; Naberezhnev, D.; Duo, J.; Nuclear Engineering Division

    2008-10-31

    Argonne National Laboratory (ANL) of USA and Kharkov Institute of Physics and Technology (KIPT) of Ukraine have been collaborating on the conceptual design development of an experimental neutron source facility based on the use of an electron accelerator driven subcritical (ADS) facility [1]. The facility uses the existing electron accelerators of KIPT in Ukraine. The neutron source of the sub-critical assembly is generated from the interaction of 100 KW electron beam with a natural uranium target. The electron beam has a uniform spatial distribution and the electron energy in the range of 100 to 200 MeV, [2]. The main functions of the facility are the production of medical isotopes and the support of the Ukraine nuclear power industry. Reactor physics experiments and material performance characterization will also be carried out. The subcritical assembly is driven by neutrons generated by the electron beam interactions with the target material. A fraction of these neutrons has an energy above 50 MeV generated through the photo nuclear interactions. This neutron fraction is very small and it has an insignificant contribution to the subcritical assembly performance. However, these high energy neutrons are difficult to shield and they can be slowed down only through the inelastic scattering with heavy isotopes. Therefore the shielding design of this facility is more challenging relative to fission reactors. To attenuate these high energy neutrons, heavy metals (tungsten, iron, etc.) should be used. To reduce the construction cost, heavy concrete with 4.8 g/cm{sup 3} density is selected as a shielding material. The iron weight fraction in this concrete is about 0.6. The shape and thickness of the heavy concrete shield are defined to reduce the biological dose equivalent outside the shield to an acceptable level during operation. At the same time, special attention was give to reduce the total shield mass to reduce the construction cost. The shield design is configured

  8. Design and Synthesis of 3, 4-Dihydropyrrolo[2, 1-c][1,4]oxazin-1-one and its 7-Acyl Derivatives

    Institute of Scientific and Technical Information of China (English)

    Yong En GUO; Bin FU; Ying Xiang LIU

    2003-01-01

    Starting from 1H-pyrrole, unreported 3, 4-dihydropyrrolo[2, 1-c][1, 4]oxazin-1-one 4,7-(4-chlorobenzoyl)-3, 4-dihydropyrrolo[2, 1-c][1, 4]oxazin-l-one 5 and 7-benzoyl-3, 4-dihydro-pyrrolo [2, 1-c][1, 4]oxazin-1-one 9 were designed and synthesized. They may have antipyretic andanalgesic activities.

  9. Design, fabrication and testing results of vacuum vessel, thermal shield and cryostat of EAST

    International Nuclear Information System (INIS)

    The EAST (Experimental Advanced Superconducting Tokamak) is an advanced steady-state plasma physics experimental device, which has been approved by the Chinese government and being constructed as the Chinese national nuclear fusion Research project. Vacuum vessel is the location for the operation of plasma as one of the key component for EAST device. During it operation the vacuum vessel will not only endure the electromagnetic force due to the plasma disruption and Halo current but also the pressure of boride water and the thermal stress owing to the 250 deg C baking out by the hot pressure nitrogen gas or the 100 deg C hot wall during plasma operation. The cryostat is a large single walled vessel surrounding the entire Basic Machine with central cylindrical section and two end enclosures, a flat base structure with external reinforcements and dome-shaped lid structure. It provides the thermal barrier with the base pressure of 5x10-4 Pa between the ambient temperature testing hall and the liquid helium cooled superconducting magnet. The thermal shields comprise the vacuum vessel thermal shield (VVTS), between the vacuum vessel and the cold TF coil structures, the cryostat thermal shield (CTS), covering the walls of the cryostat, thereby preventing direct line of sight of the room temperature walls to the cold structures, the vacuum port thermal shields (VPTS) that enclose the port connection ducts. The thermal shields are made of double-wall panels, sandwich structure consist of two stainless steel panels and weld quadrate cooling pipe in between the total surface of the thermal shields is about 351 m2. This paper is a report of the structure design and mechanical analyses on the vacuum vessel, thermal shield and cryostat. According to the allowable stress criteria of ASME, the maximum integrated stress intensity on these key components is less than the allowable design stress intensity 3 Sm. The fabrication for these components was completed in 2004 and has been

  10. Design and fabrication of shielding for gamma spectrometry

    International Nuclear Information System (INIS)

    To have a system of gamma spectrometry in the Radiological Mobile Unit No. 1 (UMOR-1) was designed and manufactured an armor-plating appropriate to this, to make analysis of radioactive samples in place in the event of a radiological emergency, besides being able to give support to the Management of Radiological Safety, and even to give service of sample analysis of other Institutions. (Author)

  11. Shielding Design for Adjacent, Underground Buildings of a Megavoltage Radiotherapy Facility.

    Science.gov (United States)

    Sanz, Darío Esteban

    2016-07-01

    In a radiotherapy facility, safety in areas next to the treatment room can be of concern when irradiating downward due to oblique x-ray transmission through the floor and/or walls, especially in areas immediately adjacent or underground. Even when there is no basement underneath, a usual conservative solution is to build a thick concrete slab as the base for the treatment room. Of course, this implies deeper soil excavation and higher associated costs. As a convenient alternative, the limiting walls can be buried a certain depth below floor level to shield oblique, downward irradiation. Besides, for space considerations, laminated barriers are usually employed, and some additional shielding to the floor may be required (L-shaped barriers). In this work, the author introduces an analytical method for calculating the required wall penetration below floor level or, alternatively, the additional floor shielding for L-shaped barriers, taking into account in either case the attenuation properties of the earth underneath the vault. Interestingly, the required penetration depth for a given wall barrier (primary or secondary), relative to a reference thickness, is only a function of basic attenuation data. Likewise, for a laminated, lead-concrete barrier, the required dimensions depend on the relative amount of lead used for the wall and on the corresponding attenuation data. The shielding design criteria developed in this work to protect underground nearby sites is conservative in nature, yet it yields optimal shield dimensions for wall footing and for wall-floor shielding, avoiding the need to construct oversized concrete slab floors. PMID:27218288

  12. Metal-wool heat shields for space shuttle. [design, fabrication, and attachment to structure

    Science.gov (United States)

    Miller, R. C.; Clure, J. L.

    1974-01-01

    The packaging of metal wool for reusable thermal heat shields applied to aerodynamic and other surfaces for the space shuttle was analyzed and designed, and samples were fabricated and experimentally studied. Parametric trends were prepared for selected configurations. An all-metal thermally efficient, reliable, reusable and producible heat shield system was designed and structurally tested for use on spacecraft aerodynamic surfaces where temperatures do not exceed 810 K. Stainless steel sheet, primarily for structure and secondarily in the transverse plane for thermal expansion, was shown to accommodate thermal expansion in all directions when restrained at the edges and heated to 1360 K. Aerodynamic loads of 0.35 x 1000,000 newtons/sq meter, and higher, may be easily accepted by structures of this design. Seven all-metal thermal protection specimens, 12.7 cm square and 2.5 cm thick were fabricated and are being experimentally evaluated at simulated shuttle entry conditions in an arc jet facility.

  13. The study on mix radio design and construction technology of radiation-shielding and high-density concrete

    International Nuclear Information System (INIS)

    Newly-constructed nuclear facilities requires the shielding concrete with density of 4600 kg/m3 or even higher for shielding of γ rays or neutron rays. Systemic tests and studies on radiation shielding concrete (neutrons and γ-ray absorbing) were conducted in such aspects as mix ratio design, preparation, construction technology, shielding effect, uniform shielding etc. The results show concrete for γ ray could be prepared with an average density of 4670 kg/m3, compressive strength of 37 MPa and permeability-resistant grade of P10. For neutron ray shield, the prepared concrete could be at an average density of 4680 kg/m3, with crystal water of 2.65% (wt) and boron of 0.11% (wt), and compressive strength of 45.6 MPa. (authors)

  14. Basic design of shield blocks for a spallation neutron source under the high-intensity proton accelerator project

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Katsuhiko; Maekawa, Fujio; Takada, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Under the JAERI-KEK High-Intensity Proton Accelerator Project (J-PARC), a spallation neutron source driven by a 3 GeV-1 MW proton beam is planed to be constructed as a main part of the Materials and Life Science Facility. Overall dimensions of a biological shield of the neutron source had been determined by evaluation of shielding performance by Monte Carlo calculations. This report describes results of design studies on an optimum dividing scheme in terms of cost and treatment and mechanical strength of shield blocks for the biological shield. As for mechanical strength, it was studied whether the shield blocks would be stable, fall down or move to a horizontal direction in case of an earthquake of seismic intensity of 5.5 (250 Gal) as an abnormal load. For ceiling shielding blocks being supported by both ends of the long blocks, maximum bending moment and an amount of maximum deflection of their center were evaluated. (author)

  15. Physical analysis of the shielding capacity for a lightweight apron designed for shielding low intensity scattering X-rays

    Science.gov (United States)

    Kim, Seon Chil; Choi, Jeong Ryeol; Jeon, Byeong Kyou

    2016-07-01

    The purpose of this paper is to develop a lightweight apron that will be used for shielding low intensity radiation in medical imaging radiography room and to apply it to a custom-made effective shielding. The quality of existing aprons made for protecting our bodies from direct radiation are improved so that they are suitable for scattered X-rays. Textiles that prevent bodies from radiation are made by combining barium sulfate and liquid silicon. These materials have the function of shielding radiation in a manner like lead. Three kinds of textiles are produced. The thicknesses of each textile are 0.15 mm, 0.21 mm, and 0.29 mm and the corresponding lead equivalents are 0.039 mmPb, 0.095 mmPb, 0.22 mmPb for each. The rate of shielding space scattering rays are 80% from the distance of 0.5 m, 86% from 1.0 m, and 97% from 1.5 m. If we intend to approach with the purpose of shielding scattering X-rays and low intensity radiations, it is possible to reduce the weight of the apron to be 1/5 compared to that of the existing lead aprons whose weight is typically more than 4 kg. We confirm, therefore, that it is possible to produce lightweight aprons that are used for the purpose of shielding low dose radiations.

  16. Physical analysis of the shielding capacity for a lightweight apron designed for shielding low intensity scattering X-rays.

    Science.gov (United States)

    Kim, Seon Chil; Choi, Jeong Ryeol; Jeon, Byeong Kyou

    2016-01-01

    The purpose of this paper is to develop a lightweight apron that will be used for shielding low intensity radiation in medical imaging radiography room and to apply it to a custom-made effective shielding. The quality of existing aprons made for protecting our bodies from direct radiation are improved so that they are suitable for scattered X-rays. Textiles that prevent bodies from radiation are made by combining barium sulfate and liquid silicon. These materials have the function of shielding radiation in a manner like lead. Three kinds of textiles are produced. The thicknesses of each textile are 0.15 mm, 0.21 mm, and 0.29 mm and the corresponding lead equivalents are 0.039 mmPb, 0.095 mmPb, 0.22 mmPb for each. The rate of shielding space scattering rays are 80% from the distance of 0.5 m, 86% from 1.0 m, and 97% from 1.5 m. If we intend to approach with the purpose of shielding scattering X-rays and low intensity radiations, it is possible to reduce the weight of the apron to be 1/5 compared to that of the existing lead aprons whose weight is typically more than 4 kg. We confirm, therefore, that it is possible to produce lightweight aprons that are used for the purpose of shielding low dose radiations.

  17. Design and fabrication of radiation shielded laser ablation ICP-MS system

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Yeong Keong; Han, Sun Ho; Park, Soon Dal; Park, Yang Soon; Jee, Kwang Yong; Kim, Won Ho

    2006-09-15

    In relation to high burn up and extended fuel cycle for the fuel cycle efficiency, we need to take chemical analysis of spent nuclear fuel for the integrity of nuclear fuel at high burn up. to measure the isotopic distribution of fission product in a high burn up nuclear fuel, radiation shielded laser ablation system was designed and fabricated. By probing the sample with a laser beam, micro sampling system for the mass analyzer was successfully developed. This report describes the structural design and the function of developed radiation shielded LA system. This system will be used for the analysis of isotopic distribution from core to rim of a spent nuclear fuel prepared from the hot-cell in PIE facility and/or an irradiated fuel from research reactor.

  18. Optimized design of shields for diagnostic X rays with NCRP 147 technique

    International Nuclear Information System (INIS)

    A comparison among the design techniques of shielding for X-ray diagnostic rooms with the NCRP 49 (1976) report technique, AAPM 39 (1993) Y the one of the NCRP 147 (2005) technique. The designs correspond to a room of conventional X-rays, one of fluoroscopy, one of tomography Y one of mammography. In all the cases it demonstrates that the NCRP 49 technique overestimate the shieldings. The causes of the overestimation of the NCRP 49 can be attributed to: a) high values of the work charge that don't consider the spectral fluence of the photons that are present in each room, b) to the differences in the values of the kerma in air without attenuation for the dispersed primary radiation Y of leakage among both reports. (Author)

  19. On an optimized neutron shielding for an advanced molten salt fast reactor design

    International Nuclear Information System (INIS)

    The molten salt reactor technology has gained renewed interest. In contrast to the historic molten salt reactors, the current projects are based on designing a molten salt fast reactor. Thus the shielding becomes significantly more challenging than in historic concepts. One very interesting and innovative result of the most recent EURATOM project on molten salt reactors – EVOL – is the fluid flow optimized design of the inner core vessel using curved blanket walls. The developed structure leads to a very uniform flow distribution. The design avoids all core internal structures. On the basis of this new geometry a model for neutron physics calculation is presented and applied for a shielding optimization. Based on these results an optimized shielding strategy is developed for the molten salt fast reactor to keep the fluence in the safety related outer vessel below expected limit values. A lifetime of 80 years can be assured, but the size of the core/blanket system has to be significantly increased and will finally be comparable to a sodium cooled fast reactor. The HELIOS results are verified against Monte-Carlo calculations with very satisfactory agreement for a deep penetration problem. (author)

  20. Rational design of an AKR1C3-resistant analog of PR-104 for enzyme-prodrug therapy.

    Science.gov (United States)

    Mowday, Alexandra M; Ashoorzadeh, Amir; Williams, Elsie M; Copp, Janine N; Silva, Shevan; Bull, Matthew R; Abbattista, Maria R; Anderson, Robert F; Flanagan, Jack U; Guise, Christopher P; Ackerley, David F; Smaill, Jeff B; Patterson, Adam V

    2016-09-15

    The clinical stage anti-cancer agent PR-104 has potential utility as a cytotoxic prodrug for exogenous bacterial nitroreductases expressed from replicating vector platforms. However substrate selectivity is compromised due to metabolism by the human one- and two-electron oxidoreductases cytochrome P450 oxidoreductase (POR) and aldo-keto reductase 1C3 (AKR1C3). Using rational drug design we developed a novel mono-nitro analog of PR-104A that is essentially free of this off-target activity in vitro and in vivo. Unlike PR-104A, there was no biologically relevant cytotoxicity in cells engineered to express AKR1C3 or POR, under aerobic or anoxic conditions, respectively. We screened this inert prodrug analog, SN34507, against a type I bacterial nitroreductase library and identified E. coli NfsA as an efficient bioactivator using a DNA damage response assay and recombinant enzyme kinetics. Expression of E. coli NfsA in human colorectal cancer cells led to selective cytotoxicity to SN34507 that was associated with cell cycle arrest and generated a robust 'bystander effect' at tissue-like cell densities when only 3% of cells were NfsA positive. Anti-tumor activity of SN35539, the phosphate pre-prodrug of SN34507, was established in 'mixed' tumors harboring a minority of NfsA-positive cells and demonstrated marked tumor control following heterogeneous suicide gene expression. These experiments demonstrate that off-target metabolism of PR-104 can be avoided and identify the suicide gene/prodrug partnership of E. coli NfsA/SN35539 as a promising combination for development in armed vectors.

  1. A robust approach to the design of an electromagnetic shield based on pyrolitic carbon

    Science.gov (United States)

    Lamberti, Patrizia; Kuzhir, Polina; Tucci, Vincenzo

    2016-07-01

    A robust approach to the design of an electromagnetic shield based on ultra-thin pyrolytic carbon (PyC, 5 ÷ 110 nm) films is proposed. Finite Element Method (FEM) simulations and Monte Carlo based tolerance analysis are used to show that even a deviation of 15 ÷ 20% from the nominal values of the most important design parameters of the PyC film, i.e. its thickness and sheet resistance, does not significantly affect the wanted level of electromagnetic interference shielding efficiency (EMI SE). The ranges of the SE show that EMI shield based on PyC film is characterized by a robust behavior with respect to the variation of such parameters due to the production processes. Therefore, since the PyC can be produced on a scalable basis, is chemically inert, significantly transparent in the visible range and can be deposited onto both metal and dielectric substrates, including flexible polymers, it may be appropriate for the highly demanding technological needs associated to the graphene revolution and can be developed from laboratory to mass production applications.

  2. Effects of radiobiological uncertainty on shield design for a 60-day lunar mission

    Science.gov (United States)

    Wilson, John W.; Nealy, John E.; Schimmerling, Walter

    1993-01-01

    Some consequences of uncertainties in radiobiological risk due to galactic cosmic ray exposure are analyzed to determine their effect on engineering designs for a first lunar outpost - a 60-day mission. Quantitative estimates of shield mass requirements as a function of a radiobiological uncertainty factor are given for a simplified vehicle structure. The additional shield mass required for compensation is calculated as a function of the uncertainty in galactic cosmic ray exposure, and this mass is found to be as large as a factor of 3 for a lunar transfer vehicle. The additional cost resulting from this mass is also calculated. These cost estimates are then used to exemplify the cost-effectiveness of research.

  3. Designing shielded radio-frequency phased-array coils for magnetic resonance imaging

    Institute of Scientific and Technical Information of China (English)

    Xu Wen-Long; Zhang Ju-Cheng; Li Xia; Xu Bing-Qiao; Tao Gui-Sheng

    2013-01-01

    In this paper,an approach to the design of shielded radio-frequency (RF) phased-array coils for magnetic resonance imaging (MRI) is proposed.The target field method is used to find current densities distributed on primary and shield coils.The stream function technique is used to discretize current densities and to obtain the winding patterns of the coils.The corresponding highly ill-conditioned integral equation is solved by the Tikhonov regularization with a penalty function related to the minimum curvature.To balance the simplicity and smoothness with the homogeneity of the magnetic field of the coil's winding pattern,the selection of a penalty factor is discussed in detail.

  4. Mechanical design and analysis for a EPR first wall/blanket/shield system

    International Nuclear Information System (INIS)

    Continuing studies are in progress at ANL to expand upon the design of a first wall/blanket/shield FW/B/S system and power conversion for a tokamak type Experimental Power Reactor (EPR). The FW/B/S system has evolved from an earlier design for a low beta, circular cross section plasma (major radius = 6 m) to one for a higher beta elongated plasma with a 4.7 m major radius. Basic mechanical design and layout features of the old and new EPR designs showing some of the more important design developments are given. These developments are aimed at simplifying the design, reducing the costs and in addition, improving the plant thermal efficiency and overall maintainability. In the area of the reactor blanket, significant thermal hydraulic and stress analysis have been performed to substantiate the integrity of the chosen concept. This paper deals with the discussion of these improved features

  5. Mechanical design and analysis for a EPR first wall/blanket/shield system

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, H.C.; Misra, B.; Youngdahl, C.K.

    1977-01-01

    Continuing studies are in progress at ANL to expand upon the design of a first wall/blanket/shield FW/B/S system and power conversion for a tokamak type Experimental Power Reactor (EPR). The FW/B/S system has evolved from an earlier design for a low beta, circular cross section plasma (major radius = 6 m) to one for a higher beta elongated plasma with a 4.7 m major radius. Basic mechanical design and layout features of the old and new EPR designs showing some of the more important design developments are depicted. These developments are aimed at simplifying the design, reducing the costs and, in addition, improving the plant thermal efficiency and overall maintainability. In the area of the reactor blanket, significant thermal hydraulic and stress analysis have been performed to substantiate the integrity of the chosen concept. This paper deals with the discussion of these improved features.

  6. Principle of shielding design for the target cave of a high current medical cyclotron

    International Nuclear Information System (INIS)

    Full text: During routine isotope production regimen at the H-ion Medical Cyclotron of the Radiopharmaceutical Division of ANSTO a thick copper plate electroplated with enriched target material is bombarded with a 30 MeV proton beam at 250μA which results in the production of fast evaporation neutrons with an average energy of 5.1 MeV (Nakamura, T. et al, Nucl Sci Engg, 83: 444-458, 1992). This paper highlights the principle of shielding design using the empirical method (Mukherjee, B. Proc. 14th Int. Conf. on Cyclotrons and their Applications, Cape Town, South Africa, October 1995) for a new target cave proposed to house a solid target irradiation station to be bombarded with a proton beam of 500μA and thereby producing an intense flux of fast neutrons. Important nuclear data such as the neutron and gamma source terms defined as the corresponding dose equivalent rates for lμA proton beam current at 1m from the target as well as the neutron energy distribution required for the shielding calculations were previously estimated experimentally (Mukherjee, B. Proc. 14th Int. Conf. on Cyclotrons and their Applications, Cape Town, South Africa, October 1995). The neutron attenuation coefficients of the 4 legged maze were explicitly evaluated from experiments conducted in the existing cyclotron vault and beam room (Mukherjee, B. et al, Appl Radiat Isot, in print, June 1996). Low sodium content high density (2350 kg.m-3) concrete was used as the shielding material. The optimum lateral thicknesses of the shielding walls (t1 and t2) were calculated to be 2.1 m and 2.5 m and the length of the maze legs (ab, bc, cd, de) were evaluated as 1.2 m, 3.1 m, 1.5 m and 6 m respectively. The dose equivalent (gamma plus neutron) rates at the locations of interest 'P1', 'P2' and 'e' were set at 0.5 μSvh-1, 10 pSvh-1 and 10 μSvh-1 respectively. The neutron shielding calculation method presented in this paper was found to be more suitable than the Monte Carlo code generally used for

  7. Empirical shielding design data for facilities administering I131 for thyroid carcinoma

    International Nuclear Information System (INIS)

    Retrospective review of the records for 434 post thyroidectomy patients receiving I131 therapy for thyroid carcinoma revealed approximately 75% of the patients were discharged within 48 hours and 90% within 72 hours. Criterion for discharge was an external radiation dose below 25 μSv/hr, measured at one metre anterior to the patient's neck. The time-averaged average dose rate at one metre anterior to the neck of a typical patient during the isolation period was 72 μSv/hr, with 90% of the patients below 82 μSv/hr. After correcting for the effects of patient size and scatter, the effective design dose rate from a patient in an isolation room treating two or three patients/week is 105 μSv.m2.hr-1, or 75 μSv.m2.hr-1 where only one patient is treated each week. Concrete is the most economical shielding material, with 190 mm filled concrete block walls and 150+mm concrete floors as the minimum recommended shielding for a radioiodine therapy suite. Additional shielding will be required if the suite adjoins (including areas immediately above and below) areas with a high occupancy factor. Copyright (1998) Australasian Physical and Engineering Sciences in Medicine

  8. Calculation of an optimized design of magnetic shields with integrated demagnetization coils

    Science.gov (United States)

    Sun, Z.; Schnabel, A.; Burghoff, M.; Li, L.

    2016-07-01

    Magnetic shielding made from permalloy is frequently used to provide a time-stable magnetic field environment. A low magnetic field and low field gradients inside the shield can be obtained by using demagnetization coils through the walls, encircling edges of the shield. We first introduce and test the computational models to calculate magnetic properties of large size shields with thin shielding walls. We then vary the size, location and shape of the openings for the demagnetization coils at the corners of a cubic shield. It turns out that the effect on the shielding factor and the expected influence on the residual magnetic field homogeneity in the vicinity of the center of the shield is negligible. Thus, a low-cost version for the openings can be chosen and their size could be enlarged to allow for additional cables and easier handling. A construction of a shield with beveled edges and open corners turned out to substantially improve the shielding factor.

  9. Methods for U.S. shielding calculations: applications to FFTF and CRBR designs

    International Nuclear Information System (INIS)

    The primary components of the U.S. reactor shielding methodology consist of: (1) computer code systems based on discrete ordinates or Monte Carlo radiation transport calculational methods; (2) a data base of neutron and gamma-ray interaction and gamma-ray-production cross sections used as input in the codes; (3) a capability for processing the cross sections into multigroup or point energy formats as required by the codes; (4) large-scale integral shielding experiments designed to test cross-section data or techniques utilized in the calculations; and (5) a ''sensitivity'' analysis capability that can identify the most important interactions in a transport calculation and assign uncertainties to the calculated result that are based on uncertainties in all of the input data. The required accuracy for the methodology is to within 5 to 10% for responses at locations near the core to within a factor of 2 for responses at distant locations. Under these criteria, the methodology has proved to be adequate for in-vessel LMFBR calculations of neutron transport through deep sodium and thick iron and stainless steel shields, of neutron streaming through lower axial coolant channels and primary pipe chaseways, and of the effects of fuel stored within the reactor vessel. For ex-vessel LMFBR problems, the methodology requires considerable improvement, the areas of concern including neutron streaming through heating and ventilation ducts, through the cavity surrounding the reactor vessel, and through gaps around rotating plugs in the reactor heat, as well as gamma-ray streaming through plant shield penetrations

  10. Design of piezoelectric transducer layer with electromagnetic shielding and high connection reliability

    Science.gov (United States)

    Qiu, Lei; Yuan, Shenfang; Shi, Xiaoling; Huang, Tianxiang

    2012-07-01

    Piezoelectric transducer (PZT) and Lamb wave based structural health monitoring (SHM) method have been widely studied for on-line SHM of high-performance structures. To monitor large-scale structures, a dense PZTs array is required. In order to improve the placement efficiency and reduce the wire burden of the PZTs array, the concept of the piezoelectric transducers layer (PSL) was proposed. The PSL consists of PZTs, a flexible interlayer with printed wires and signal input/output interface. For on-line SHM on real aircraft structures, there are two main issues on electromagnetic interference and connection reliability of the PSL. To address the issues, an electromagnetic shielding design method of the PSL to reduce spatial electromagnetic noise and crosstalk is proposed and a combined welding-cementation process based connection reliability design method is proposed to enhance the connection reliability between the PZTs and the flexible interlayer. Two experiments on electromagnetic interference suppression are performed to validate the shielding design of the PSL. The experimental results show that the amplitudes of the spatial electromagnetic noise and crosstalk output from the shielded PSL developed by this paper are - 15 dB and - 25 dB lower than those of the ordinary PSL, respectively. Other two experiments on temperature durability ( - 55 °C-80 °C ) and strength durability (160-1600μɛ, one million load cycles) are applied to the PSL to validate the connection reliability. The low repeatability errors (less than 3% and less than 5%, respectively) indicate that the developed PSL is of high connection reliability and long fatigue life.

  11. Computer simulation in the design of local exhaust hoods for shielded metal arc welding.

    Science.gov (United States)

    Tum Suden, K D; Flynn, M R; Goodman, R

    1990-03-01

    Computer simulations were used to examine competing exhaust hood configurations for shielded metal arc welding. The welder's breathing zone concentration appears to be an inverse linear function of the computer-predicted hood capture efficiency. Hood aspect ratio, hood flow, and the welder's position relative to the hood all have a significant effect on the breathing zone concentration. The height of the hood above the welding surface showed no significant effect in reducing breathing zone concentration. Further examination of breathing zone concentration as a function of capture efficiency is needed before reliable design methods can be developed using this parameter.

  12. Design of a Laboratory Hall Thruster with Magnetically Shielded Channel Walls, Phase I: Numerical Simulations

    Science.gov (United States)

    Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.

    2011-01-01

    In a proof-of-principle effort to demonstrate the feasibility of magnetically shielded (MS) Hall thrusters, an existing laboratory thruster has been modified with the guidance of physics-based numerical simulation. When operated at a discharge power of 6-kilowatts the modified thruster has been designed to reduce the total energy and flux of ions to the channel insulators by greater than 1 and greater than 3 orders of magnitude, respectively. The erosion rates in this MS thruster configuration are predicted to be at least 2-4 orders of magnitude lower than those in the baseline (BL) configuration. At such rates no detectable erosion is expected to occur.

  13. Design verification of large time constant thermal shields for optical reference cavities.

    Science.gov (United States)

    Zhang, J; Wu, W; Shi, X H; Zeng, X Y; Deng, K; Lu, Z H

    2016-02-01

    In order to achieve high frequency stability in ultra-stable lasers, the Fabry-Pérot reference cavities shall be put inside vacuum chambers with large thermal time constants to reduce the sensitivity to external temperature fluctuations. Currently, the determination of thermal time constants of vacuum chambers is based either on theoretical calculation or time-consuming experiments. The first method can only apply to simple system, while the second method will take a lot of time to try out different designs. To overcome these limitations, we present thermal time constant simulation using finite element analysis (FEA) based on complete vacuum chamber models and verify the results with measured time constants. We measure the thermal time constants using ultrastable laser systems and a frequency comb. The thermal expansion coefficients of optical reference cavities are precisely measured to reduce the measurement error of time constants. The simulation results and the experimental results agree very well. With this knowledge, we simulate several simplified design models using FEA to obtain larger vacuum thermal time constants at room temperature, taking into account vacuum pressure, shielding layers, and support structure. We adopt the Taguchi method for shielding layer optimization and demonstrate that layer material and layer number dominate the contributions to the thermal time constant, compared with layer thickness and layer spacing. PMID:26931831

  14. Advancing Control for Shield Tunneling Machine by Backstepping Design with LuGre Friction Model

    Directory of Open Access Journals (Sweden)

    Haibo Xie

    2014-01-01

    Full Text Available Shield tunneling machine is widely applied for underground tunnel construction. The shield machine is a complex machine with large momentum and ultralow advancing speed. The working condition underground is rather complicated and unpredictable, and brings big trouble in controlling the advancing speed. This paper focused on the advancing motion control on desired tunnel axis. A three-state dynamic model was established with considering unknown front face earth pressure force and unknown friction force. LuGre friction model was introduced to describe the friction force. Backstepping design was then proposed to make tracking error converge to zero. To have a comparison study, controller without LuGre model was designed. Tracking simulations of speed regulations and simulations when front face earth pressure changed were carried out to show the transient performances of the proposed controller. The results indicated that the controller had good tracking performance even under changing geological conditions. Experiments of speed regulations were carried out to have validations of the controllers.

  15. Design and construction of shield tunnel for underground railway in Kuala Lumpur of Malaysia; Kuala Lumpur ni okeru chikatetsu shield no sekkei to seko

    Energy Technology Data Exchange (ETDEWEB)

    Sonoda, T. [Hazama Corp., Tokyo (Japan); Singh, M.

    1998-01-01

    This report involves the shield tunnel design and construction for a 1.5m-long section of the 3km-long tunnel of LRT System II with part of its new linear line crossing Kuala Lumpur in a north-south direction. The basement consists of sedimentary rock called Kenny Hill formation and limestone, and they are surrounded by granite intrusive bodies. The soil as a whole is complicated in structure, with some part found quite soft, thanks to thermal metamorphosis resulting from high-temperature, high-humidity climatic conditions, and to the granite intrusion. For the shield application process, solidified Kenny Hill strata, weathered or unweathered, are assumed to be provided with an N value of 50 or higher, and cutter heads are chosen accordingly. During the excavation, there are encounters with quartzite concealed in thermally metamorphosed rocks for a rapid wear of cutter heads. There occurs, again, a tunnel face collapse to reach the ground surface caused by changes in stress in the basement due to excavation and by slaking (the disintegration of tunnel walls in swelling clay) of thermally metamorphosed rocks. For the prevention of groundwater from arriving at the outer circumference of the shielding machine, chemical grouting is performed every 0.5m of drilling for the prevention of collapse. 6 figs., 2 tabs.

  16. Design and performance of new type carbon fiber reinforced polyimide-based composites for X/γ photon shielding

    International Nuclear Information System (INIS)

    Background: With the rapid development of radiation technology, demands of functional and structural integration have been put forward for the photon shielding material. Purpose: To meet this need, a new type of carbon fiber reinforced polyimide composite has been designed and tested. Methods: Shielding properties of composite materials of different PbO contents are modeled based on MCNP. According to the simulation results, shielding material is designed and prepared. And its shielding properties, mechanical properties as well as radiation-resistant properties are tested. Results: Through photon shield experiment and mechanical performance experiment, the composite material has good shielding performance for photons. Its photon transmission rate at thickness of 4.80-mm is 54.13% for 137Cs (662 keV) gamma-ray, bend strength and stretch strength at l.2-mm thickness can reach 263 MPa and 369 MPa, respectively. After 90-kGy irradiation, the stretch strength can retain 83.47% of its performance. Conclusion: Therefore, the material possesses great application potential in medicine and industry such as gamma ray flaw detection. (authors)

  17. Design and validation of a large-format transition edge sensor array magnetic shielding system for space application

    Science.gov (United States)

    Bergen, A.; van Weers, H. J.; Bruineman, C.; Dhallé, M. M. J.; Krooshoop, H. J. G.; ter Brake, H. J. M.; Ravensberg, K.; Jackson, B. D.; Wafelbakker, C. K.

    2016-10-01

    The paper describes the development and the experimental validation of a cryogenic magnetic shielding system for transition edge sensor based space detector arrays. The system consists of an outer mu-metal shield and an inner superconducting niobium shield. First, a basic comparison is made between thin-walled mu-metal and superconducting shields, giving an off-axis expression for the field inside a cup-shaped superconductor as a function of the transverse external field. Starting from these preliminary analytical considerations, the design of an adequate and realistic shielding configuration for future space flight applications (either X-IFU [D. Barret et al., e-print arXiv:1308.6784 [astro-ph.IM] (2013)] or SAFARI [B. Jackson et al., IEEE Trans. Terahertz Sci. Technol. 2, 12 (2012)]) is described in more detail. The numerical design and verification tools (static and dynamic finite element method (FEM) models) are discussed together with their required input, i.e., the magnetic-field dependent permeability data. Next, the actual manufacturing of the shields is described, including a method to create a superconducting joint between the two superconducting shield elements that avoid flux penetration through the seam. The final part of the paper presents the experimental verification of the model predictions and the validation of the shield's performance. The shields were cooled through the superconducting transition temperature of niobium in zero applied magnetic field (<10 nT) or in a DC field with magnitude ˜100 μT, applied either along the system's symmetry axis or perpendicular to it. After cool-down, DC trapped flux profiles were measured along the shield axis with a flux-gate magnetometer and the attenuation of externally applied AC fields (100 μT, 0.1 Hz, both axial and transverse) was verified along this axis with superconducting quantum interference device magnetometers. The system's measured on-axis shielding factor is greater than 106, well exceeding

  18. Multiphysics Engineering Analysis for an Integrated Design of ITER Diagnostic First Wall and Diagnostic Shield Module Design

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Y. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Loesser, G. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Smith, M. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Udintsev, V. [ITER Org, F-13115 St Paul Les Durance, France.; Giacomin, T., T. [ITER Org, F-13115 St Paul Les Durance, France.; Khodak, A. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Johnson, D, [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Feder, R, [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

    2015-07-01

    ITER diagnostic first walls (DFWs) and diagnostic shield modules (DSMs) inside the port plugs (PPs) are designed to protect diagnostic instrument and components from a harsh plasma environment and provide structural support while allowing for diagnostic access to the plasma. The design of DFWs and DSMs are driven by 1) plasma radiation and nuclear heating during normal operation 2) electromagnetic loads during plasma events and associate component structural responses. A multi-physics engineering analysis protocol for the design has been established at Princeton Plasma Physics Laboratory and it was used for the design of ITER DFWs and DSMs. The analyses were performed to address challenging design issues based on resultant stresses and deflections of the DFW-DSM-PP assembly for the main load cases. ITER Structural Design Criteria for In-Vessel Components (SDC-IC) required for design by analysis and three major issues driving the mechanical design of ITER DFWs are discussed. The general guidelines for the DSM design have been established as a result of design parametric studies.

  19. CSR的辐射屏蔽设计%Radiation Shielding Design of CSR

    Institute of Scientific and Technical Information of China (English)

    苏有武; 李武元; 李宗强; 郑华智; 朱小龙

    2005-01-01

    The construction of CSR (cooling storage ring) which includes a main ring (CSRm) and an experimental ring (CSRe) will be finished at the end of 2005. Heavy ions of carbon to uranium will be accelerated up to 900MeV/u and 400MeV/u at intensity of 108 pps. The HIRFL (heavy ion research facility in Lanzhou)will be used as the injector. For the shielding design of CSR, the secondary neutrons due to the ion beam loss,their spectra and angular distributions were estimated based on the experimental results. The dose equivalent outside the shielding surface and in the surrounding environment and the neutron skyshine dose equivalent were also estimated in this study. The experimental result, neutron yield, spectrum and angular distribution for 400MeV/u 12C+Cu reaction were used for estimating the source term of shielding design. It is found that the most important environmental radiation impact component of CSR is the skyshine neutrons.%CSR(cooling storage ring)按计划将于2005年底建成调束,届时从12C到238U的重离子将可以分别被加速到900和400MeV的能量.HIRFL(兰州重离子加速器Heavy Ion Research Facility in Lanzhou)将用作CSR的注入器.为了CSR的屏蔽设计,本文利用现有的实验数据计算了由于束流损失产生的中子及其能谱、角分布,同时也估算了屏蔽体外表面的中子剂量、环境中子剂量及天空返照中子剂量.在源项计算中使用了400MeV/u12C+Cu反应的中子产额、能谱、角分布的实验数据.计算表明,CSR对环境剂量影响最大的是天空返照中子.

  20. Preliminary shielding analysis in support of the CSNS target station shutter neutron beam stop design

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bin; CHEN Yi-Xue; WANG Wei-Jin; YANG Shou-Hai; WU Jun; YIN Wen; LIANG Tian-Jiao; JIA Xue-Jun

    2011-01-01

    The construction of China Spallation Neutron Source (CSNS) has been initiated in Dongguan,Guangdong, China.Thus a detailed radiation transport analysis of the shutter neutron beam stop is of vital importance. The analyses are performed using the coupled Monte Carlo and multi-dimensional discrete ordinates method. The target of calculations is to optimize the neutron beamline shielding design to guarantee personal safety and minimize cost. Successful elimination of the primary ray effects via the two-dimensional uncollided flux and the first collision source methodology is also illustrated. Two-dimensional dose distribution is calculated. The dose at the end of the neutron beam line is less than 2.5μSv/h. The models have ensured that the doses received by the hall staff members are below the standard limit required.

  1. A User's Manual for the NRN Shield Design Method

    Energy Technology Data Exchange (ETDEWEB)

    Hjaerne, Leif (ed.); Aalto, E.; Fraeki, R.; Leimdoerfer, M.; Lindblom, K.; Linde, S.; Malen, K.; Nyman, K.

    1964-06-15

    This report describes a code system for bulk shield design written for a Ferranti Mercury computer and is intended as a manual for those using the programme. The idea of an 'almost direct' flux, as in the removal theory serves as a basis for further development of the theory. An important aspiration has been to minimize the manual work of administering the codes. The codes concerned are: NECO, computing necessary group constants from primary data, REFUSE and REBOX (infinite plane or cylindrical, and box geometry, respectively), computing removal flux, NEDI a one-dimensional (plane, spherical, cylindrical) diffusion multigroup code, and SALOME a Monte Carlo code computing the gamma flux. Output tapes are constructed for direct use as input tapes, when required, for a following code.

  2. Design of a control system for self-shielded irradiators with remote access capability

    International Nuclear Information System (INIS)

    With self-shielded irradiators like Gamma chambers, and Blood irradiators are being sold by BRIT to customers both within and outside the country, it has become necessary to improve the quality of service without increasing the overheads. The recent advances in the field of communications and information technology can be exploited for improving the quality of service to the customers. A state of the art control system with remote accessibility has been designed for these irradiators enhancing their performance. This will provide an easy access to these units wherever they might be located, through the Internet. With this technology it will now be possible to attend to the needs of the customers, as regards fault rectification, error debugging, system software update, performance testing, data acquisition etc. This will not only reduce the downtime of these irradiators but also reduce the overheads. (author)

  3. Mars Radiation Risk Assessment and Shielding Design for Long-term Exposure to Ionizing Space Radiation

    Science.gov (United States)

    Tripathi, Ram K.; Nealy, John E.

    2007-01-01

    NASA is now focused on the agency's vision for space exploration encompassing a broad range of human and robotic missions including missions to Moon, Mars and beyond. As a result, there is a focus on long duration space missions. NASA is committed to the safety of the missions and the crew, and there is an overwhelming emphasis on the reliability issues for space missions and the habitat. The cost-effective design of the spacecraft demands a very stringent requirement on the optimization process. Exposure from the hazards of severe space radiation in deep space and/or long duration missions is a critical design constraint and a potential 'show stopper'. Thus, protection from the hazards of severe space radiation is of paramount importance to the agency's vision. It is envisioned to have long duration human presence on the Moon for deep space exploration. The exposures from ionizing radiation - galactic cosmic radiation and solar particle events - and optimized shield design for a swing-by and a long duration Mars mission have been investigated. It is found that the technology of today is inadequate for safe human missions to Mars, and revolutionary technologies need to be developed for long duration and/or deep space missions. The study will provide a guideline for radiation exposure and protection for long duration missions and career astronauts and their safety.

  4. Upgrading the Neutron Radiography Facility in South Africa (SANRAD): Concrete Shielding Design Characteristics

    Science.gov (United States)

    de Beer, F. C.; Radebe, M. J.; Schillinger, B.; Nshimirimana, R.; Ramushu, M. A.; Modise, T.

    A common denominator of all neutron radiography (NRAD) facilities worldwide is that the perimeter of the experimental chamber of the facility is a radiation shielding structure which,in some cases, also includes flight tube and filter chamber structures. These chambers are normally both located on the beam port floor outside the biological shielding of the neutron source. The main function of the NRAD-shielding structure isto maintain a radiological safe working environment in the entire beam hall according to standards set by individual national radiological safety regulations. In addition, the shielding's integrity and capability should not allow, during NRAD operations, an increase in radiation levels in the beam port hall and thus negatively affectadjacent scientific facilities (e.g. neutron diffraction facilities).As a bonus, the shielding for the NRAD facility should also prevent radiation scattering towards the detector plane and doing so, thus increase thecapability of obtaining better quantitative results. This paper addresses Monte Carlo neutron-particletransport simulations to theoretically optimize the shielding capabilities of the biological barrierfor the SANRAD facility at the SAFARI-1 nuclear research reactor in South Africa. The experimental process to develop the shielding, based on the principles of the ANTARES facility, is described. After casting, the homogeneity distribution of these concrete mix materials is found to be near perfect and first order experimental radiation shielding characteristicsthrough film badge (TLD) exposure show acceptable values and trends in neutron- and gamma-ray attenuation.

  5. Optimal Design for Open MR/Superconducting Magnet with Active Shielding

    Institute of Scientific and Technical Information of China (English)

    Chun-zhong WANG; Qiu-liang WANG; Lan-kai LI; Ming RONG; You-yuan ZHOU

    2010-01-01

    The optimal design method for an open Magnetic Resonance Imaging(MRI)superconducting magnet with an active shielding configuration is proposed Firstly,three pairs of current rings are employed as seed coils.By optimizing the homogeneity of Diameter Sphere Volume(DSV),the positions and currents of the seed coils will be obtained.Secondly,according to the positions and currents of the seed coils,the current density of superconducting wires is determined,and then the original sections for the coils can be achieved.An optimization for the homogeneity based on the constrained nonlinear optimization method is employed to determine the coils with homogeneity.Thirdly,the magnetic field generated by previous coils is set as the background field,then add two coils with reverse current,and optimize the stray field line of 5 Gauss in a certain scope.Finally,a further optimization for the homogeneity is used to get final coils.This method can also be used in the design of other axisymmettic superconducting MRI magnets.

  6. Design calculations for a xenon plasma x-ray shield to protect the NIF optical Thomson scattering diagnostic

    Science.gov (United States)

    Swadling, G. F.; Ross, J. S.; Datte, P.; Moody, J.; Divol, L.; Jones, O.; Landen, O.

    2016-11-01

    An Optical Thomson Scattering (OTS) diagnostic is currently being developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory. This diagnostic is designed to make measurements of the hohlraum plasma parameters, such as the electron temperature and the density, during inertial confinement fusion (ICF) experiments. NIF ICF experiments present a very challenging environment for optical measurements; by their very nature, hohlraums produce intense soft x-ray emission, which can cause "blanking" (radiation induced opacity) of the radiation facing optical components. The soft x-ray fluence at the surface of the OTS blast shield, 60 cm from the hohlraum, is estimated to be ˜8 J cm-2. This is significantly above the expected threshold for the onset of "blanking" effects. A novel xenon plasma x-ray shield is proposed to protect the blast shield from x-rays and mitigate "blanking." Estimates suggest that an areal density of 1019 cm-2 Xe atoms will be sufficient to absorb 99.5% of the soft x-ray flux. Two potential designs for this shield are presented.

  7. Shielding design of an underground experimental area at point 5 of the CERN Super Proton Synchrotron (SPS).

    Science.gov (United States)

    Mueller, Mario J; Stevenson, Graham R

    2005-01-01

    Increasing projected values of the circulating beam intensity in the Super Proton Synchrotron (SPS) and decreasing limits to radiation exposure, taken with the increasing non-acceptance of unjustified and unoptimised radiation exposures, have led to the need to re-assess the shielding between the ECX and ECA5 underground experimental areas of the SPS. Twenty years ago, these experimental areas at SPS-Point 5 housed the UA1 experiment, where Carlo Rubbia and his team verified the existence of W and Z bosons. The study reported here describes such a re-assessment based on simulations using the multi-purpose FLUKA radiation transport code. This study concludes that while the main shield which is made of concrete blocks and is 4.8 m thick satisfactorily meets the current design limits even at the highest intensities presently planned for the SPS, dose rates calculated for liaison areas on both sides of the main shield significantly exceed the design limits. Possible ways of improving the shielding situation are discussed.

  8. Design of a management information system for the Shielding Experimental Reactor ageing management

    Energy Technology Data Exchange (ETDEWEB)

    He Jie, E-mail: hejiejoe@163.co [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Xu Xianhong [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China)

    2010-01-15

    The problem of nuclear reactor ageing is a topic of increasing importance in nuclear safety recent years. Ageing management is usually implemented for reactors maintenance. In the practice, a large number of data and records need to be processed. However, there are few professional software applications that aid reactor ageing management, especially for research reactors. This paper introduces the design of a new web-based management information system (MIS), named the Shielding Experimental Reactor Ageing Management Information System (SERAMIS). It is an auxiliary means that helps to collect data, keep records, and retrieve information for a research reactor ageing management. The Java2 Enterprise Edition (J2EE) and network database techniques, such as three-tiered model, Model-View-Controller architecture, transaction-oriented operations, and JavaScript techniques, are used in the development of this system. The functionalities of the application cover periodic safety review (PSR), regulatory references, data inspection, and SSCs classification according to ageing management methodology. Data and examples are presented to demonstrate the functionalities. For future work, techniques of data mining will be employed to support decision-making.

  9. Nuclear analysis and shielding optimisation in support of the ITER In-Vessel Viewing System design

    CERN Document Server

    Turner, A; Loughlin, M J; Ghani, Z; Hurst, G; Bue, A Lo; Mangham, S; Puiu, A; Zheng, S

    2014-01-01

    The In-Vessel Viewing System (IVVS) units proposed for ITER are deployed to perform in-vessel examination. During plasma operations, the IVVS is located beyond the vacuum vessel, with shielding blocks envisaged to protect components from neutron damage and reduce shutdown dose rate (SDR) levels. Analyses were conducted to determine the effectiveness of several shielding configurations. The neutron response of the system was assessed using global variance reduction techniques and a surface source, and shutdown dose rate calculations were undertaken using MCR2S. Unshielded, the absorbed dose to piezoelectric motors (PZT) was found to be below stable limits, however activation of the primary closure plate (PCP) was prohibitively high. A scenario with shielding blocks at probe level showed significantly reduced PCP contact dose rate, however still marginally exceeded port cell requirements. The addition of shielding blocks at the bioshield plug demonstrated PCP contact dose rates below project requirements. SDR l...

  10. Characterization of Magnetic Field Immersed Photomultipliers from Double Chooz Experiment. Design and Construction of their Magnetic Shields

    International Nuclear Information System (INIS)

    Flavour oscillations of neutrinos are a quantum-mechanical effect widely demonstrated. It is explained through interferences of their mass eigenstates, therefore, belonging to the physical area beyond the Standard Model. This work deals with the CIEMAT collaboration in the neutrino experiment Double Chooz. Such an experiment aims to measure the mixture angle θ13, one of the PMNS leptonic mixture matrix, with a un reached-before sensibility by decrease of systematic errors. For this, two identical scintillator detectors, equipped with PMT's, will be sited at different distances from two reactors located in the nuclear power plant CHOOZ B (France). The electronic neutrino flux from these reactors will be compared, explaining its deficit by flavour oscillations of these particles. The identity of both detectors will be diminished by the magnetic field effects on the PMT's response. Therefore, this study serves as for quantifying such an effects as for fitting the magnetic shields design that minimize them. Shielding measurements and final design of magnetic shields as much as the effect these ones cause in the PMT's response immersed in a monitored magnetic field are presented. (Author) 85 refs

  11. Design of software for calculation of shielding based on various standards radiodiagnostic calculation

    International Nuclear Information System (INIS)

    The aim of this study was to develop a software application that performs calculation shields in radiology room depending on the type of equipment. The calculation will be done by selecting the user, the method proposed in the Guide 5.11, the Report 144 and 147 and also for the methodology given by the Portuguese Health Ministry. (Author)

  12. Neutron Shielding Design for 4π BaF2 Detector Facility

    Institute of Scientific and Technical Information of China (English)

    HUANG; Xing; ZHANG; Qi-wei; HE; Guo-zhu; CHENG; Pin-jing; TANG; Hong-qing; ZHOU; Zu-ying

    2013-01-01

    Neutrons within energy range of 5 to 300 keV can be produced by pulsed proton beam striking thick lithium target,based on the HI-13 tandem accelerator.Neutron shielding is necessary when the Gamma-ray Total Absorption Facility(GTAF)is applied to measured(n,γ)reaction cross sections

  13. TRIPOLI-2: neutron gamma coupling - applications to shielding benchmarks and designs

    Energy Technology Data Exchange (ETDEWEB)

    Cramer, S.N.; Dejonghe, G.; Gonnord, J.; Nimal, J.C.; Vergnaud, T.

    1983-05-01

    Recent additions in the on-going development of the TRIPOLI Monte Carlo code system include conversion to the ENDF/B data format and an automated coupling scheme for neutron secondary gamma-ray calculations. Two shielding calculations are presented here which feature these two new developments.

  14. A1C test

    Science.gov (United States)

    HbA1C test; Glycated hemoglobin test; Glycosylated hemoglobin test; Hemoglobin glycosylated test; Glycohemoglobin test ... have recently eaten does not affect the A1C test, so you do not need to fast to ...

  15. Biological Shielding Design Effectiveness of the Brachytherapy Unit at the Korle Bu Teaching Hospital in Ghana Using Mcnp5 Monte Carlo Code

    OpenAIRE

    C.C. Arwui; E.O. Darko; P. Deatanyah; S. Wotorchi-Gordon; H. Lawluvi; Kpeglo, D. O.; G. Emi-Reynolds

    2011-01-01

    Design objectives for brachytherapy treatment facilities require sufficient shielding to reduce primary and scatter radiation to design limit in order to limit exposure to patients, staff and the general public. The primary aim of this study is to verify whether shielding of the brachytherapy unit at the Korle Bu teaching Hospital in Ghana provides adequate protection in order to assess any radiological health and safety impact and also test the suitability of other available sources. The stu...

  16. Engineering design and development of shielding door and safety shutter for transfer line-3 tunnel of Indus accelerator complex

    International Nuclear Information System (INIS)

    Indus accelerator complex houses two synchrotron radiation sources, Indus-1 and Indus-2. Electron beam from booster synchrotron is injected into lndus-2 through transfer line-3 (TL-3). In order to reduce the radiation coming from TL-3 through the door opening to Indus-1, to safe limit, a sliding shielding door has been developed. It is a close welded frame of mild steel with required thickness of shielding material in the form of interlocking lead bricks stacked inside. The door is suspended from an overhead I-beam attached to welded wall brackets, which are fixed to RCC wall using anchor fasteners. Pneumatic drive is used for moving the door. Radiation measurements carried out after the installation show substantial reduction in the radiation field at Indus-1 experimental hall. Another safety concern is the inadvertent transmission of electron beam from booster synchrotron to TL-3. For this purpose a safety shutter has been made. It comprises of a beam absorber made of high density alloy DENSIMET which can be moved in and out of electron beam path. Design, fabrication, installation and testing of sliding shielding door and the beam shutter have been described. (author)

  17. Implementation of Gy-Eq for deterministic effects limitation in shield design

    Science.gov (United States)

    Wilson, John W.; Kim, Myung-Hee Y.; De Angelis, Giovanni; Cucinotta, Francis A.; Yoshizawa, Nobuaki; Badavi, Francis F.

    2002-01-01

    The NCRP has recently defined RBE values and a new quantity (Gy-Eq) for use in estimation of deterministic effects in space shielding and operations. The NCRP's RBE for neutrons is left ambiguous and not fully defined. In the present report we will suggest a complete definition of neutron RBE consistent with the NCRP recommendations and evaluate attenuation properties of deterministic effects (Gy-Eq) in comparison with other dosimetric quantities.

  18. Design and Test of a Blast Shield for Boeing 737 Overhead Compartment

    OpenAIRE

    Xinglai Dang; Philemon C. Chan

    2006-01-01

    This work demonstrates the feasibility of using a composite blast shield for hardening an overhead bin compartment of a commercial aircraft. If a small amount of explosive escapes detection and is brought onboard and stowed in an overhead bin compartment of a passenger aircraft, the current bins provide no protection against a blast inside the compartment. A blast from the overhead bin will certainly damage the fuselage and likely lead to catastrophic inflight structural failure. The feasibil...

  19. Design and Analysis of HJ-1-C Satellite SAR Antenna%环境一号C星SAR天线设计与分析

    Institute of Scientific and Technical Information of China (English)

    郑士昆; 冀有志; 崔兆云; 方永刚; 周丽萍

    2014-01-01

    环境一号C星SAR天线采用了构架式可展开网状抛物面反射器,天线构型复杂,在轨展开步骤多,天线展开可靠性及在轨电气性能等都是设计难点。该文阐述了天线总体、结构和电气方面的设计研究,并从力学和热角度进行了实际工况的分析。环境一号C星在轨成功展开及良好的SAR成像质量表明了天线在机电热及可靠性设计方面满足型号工程的使用要求,为集中式网状抛物面SAR天线的设计研究提供了宝贵经验。%With truss deployable mesh parabolic reflector, the HJ-1-C SAR antenna has complex structure and multiple steps during the deployed processing. The design of the antenna is difficult in terms of deployed reliability and electrical performance. This paper makes intensive research on system, structure and electrical design, and the analysis of mechanical and thermal performance in the actual space conditions is also presented. The successful deploying in orbit and high image quality of the HJ-1-C satellite indicate that the mechanical, electronic, thermal and reliability design of the antenna satisfy the project requirement, and these research provides valuable experience for the design of the centralized mesh parabolic SAR antenna.

  20. 环境一号C星SAR天线设计与分析%Design and Analysis of HJ-1-C Satellite SAR Antenna

    Institute of Scientific and Technical Information of China (English)

    郑士昆; 冀有志; 崔兆云; 方永刚; 周丽萍

    2014-01-01

    With truss deployable mesh parabolic reflector, the HJ-1-C SAR antenna has complex structure and multiple steps during the deployed processing. The design of the antenna is difficult in terms of deployed reliability and electrical performance. This paper makes intensive research on system, structure and electrical design, and the analysis of mechanical and thermal performance in the actual space conditions is also presented. The successful deploying in orbit and high image quality of the HJ-1-C satellite indicate that the mechanical, electronic, thermal and reliability design of the antenna satisfy the project requirement, and these research provides valuable experience for the design of the centralized mesh parabolic SAR antenna.%环境一号C星SAR天线采用了构架式可展开网状抛物面反射器,天线构型复杂,在轨展开步骤多,天线展开可靠性及在轨电气性能等都是设计难点。该文阐述了天线总体、结构和电气方面的设计研究,并从力学和热角度进行了实际工况的分析。环境一号C星在轨成功展开及良好的SAR成像质量表明了天线在机电热及可靠性设计方面满足型号工程的使用要求,为集中式网状抛物面SAR天线的设计研究提供了宝贵经验。

  1. Design study of nuclear shielding and fuel cycle for steady-state tokamak device JT-60SU

    Energy Technology Data Exchange (ETDEWEB)

    Miya, N. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Hayashi, T. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Suzuki, Y. [Mitsubishi Electric Corporation, 2-2-3 Marunouchi, Chiyoda-ku, Tokyo (Japan); Nagashima, K. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Neyatani, Y. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Toyoshima, N. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Suzuki, T. [Kawasaki Heavy Industries, 2-6-5 Minami-suna, Koutou-ku, Tokyo (Japan); Naito, T. [Mitsubishi Heavy Industries, 1-297 Kitabukuro-cho, Omiya, Saitama (Japan); Kikuchi, M. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Nagami, M. [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment

    1997-05-01

    Conceptual design studies of nuclear shielding and fuel cycle based on nuclear safety aspects are presented for the steady-state tokamak device JT-60 Super Upgrade (JT-60SU). Combination of tungsten and SS-316 materials is newly proposed for the candidate vessel material in addition to the titanium alloy which is chosen as the low activation material so far in JT-60SU. This proposal also meets the design requirements of the nuclear shielding for a D-D neutron production rate of 1 x 10{sup 18} s{sup -1}. The fuel cycle and tritium recovery system are designed for steady-state operation with the annual tritium production of 0.2 g and gas flow rate of 20 Pam{sup 3}s{sup -1}, most of which is deuterium gas. Concepts of a multiple-barrier tritium containment system and room isolation system are employed for safe tritium processing in the system, which can prevent leakage and propagation to the environment in the case of accidental tritium release. (orig.)

  2. Collimator and shielding design for boron neutron capture therapy (BNCT) facility at TRIGA MARK II reactor

    International Nuclear Information System (INIS)

    The geometry of reactor core, thermal column, collimator and shielding system for BNCT application of TRIGA MARK II Reactor were simulated with MCNP5 code. Neutron particle lethargy and dose were calculated with MCNPX code. Neutron flux in a sample located at the end of collimator after normalized to measured value (Eid Mahmoud Eid Abdel Munem, 2007) at 1 MW power was 1.06 x 108 n/ cm2/ s. According to IAEA (2001) flux of 1.00 x 109 n/ cm2/ s requires three hours of treatment. Few modifications were needed to get higher flux. (Author)

  3. Shields-1, A SmallSat Radiation Shielding Technology Demonstration

    Science.gov (United States)

    Thomsen, D. Laurence, III; Kim, Wousik; Cutler, James W.

    2015-01-01

    The NASA Langley Research Center Shields CubeSat initiative is to develop a configurable platform that would allow lower cost access to Space for materials durability experiments, and to foster a pathway for both emerging and commercial-off-the-shelf (COTS) radiation shielding technologies to gain spaceflight heritage in a relevant environment. The Shields-1 will be Langleys' first CubeSat platform to carry out this mission. Radiation shielding tests on Shields-1 are planned for the expected severe radiation environment in a geotransfer orbit (GTO), where advertised commercial rideshare opportunities and CubeSat missions exist, such as Exploration Mission 1 (EM-1). To meet this objective, atomic number (Z) graded radiation shields (Zshields) have been developed. The Z-shield properties have been estimated, using the Space Environment Information System (SPENVIS) radiation shielding computational modeling, to have 30% increased shielding effectiveness of electrons, at half the thickness of a corresponding single layer of aluminum. The Shields-1 research payload will be made with the Z-graded radiation shields of varying thicknesses to create dose-depth curves to be compared with baseline materials. Additionally, Shields-1 demonstrates an engineered Z-grade radiation shielding vault protecting the systems' electronic boards. The radiation shielding materials' performances will be characterized using total ionizing dose sensors. Completion of these experiments is expected to raise the technology readiness levels (TRLs) of the tested atomic number (Z) graded materials. The most significant contribution of the Z-shields for the SmallSat community will be that it enables cost effective shielding for small satellite systems, with significant volume constraints, while increasing the operational lifetime of ionizing radiation sensitive components. These results are anticipated to increase the development of CubeSat hardware design for increased mission lifetimes, and enable

  4. Optimal design of structural parameters for shield cutterhead based on fuzzy mathematics and multi-objective genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    夏毅敏; 唐露; 暨智勇; 程永亮; 卞章括

    2015-01-01

    In order to improve the strength and stiffness of shield cutterhead, the method of fuzzy mathematics theory in combination with the finite element analysis is adopted. An optimal design model of structural parameters for shield cutterhead is formulated, based on the complex engineering technical requirements. In the model, as the objective function of the model is a composite function of the strength and stiffness, the response surface method is applied to formulate the approximate function of objective function in order to reduce the solution scale of optimal problem. A multi-objective genetic algorithm is used to solve the cutterhead structure design problem and the change rule of the stress−strain with various structural parameters as well as their optimal values were researched under specific geological conditions. The results show that compared with original cutterhead structure scheme, the obtained optimal scheme of the cutterhead structure can greatly improve the strength and stiffness of the cutterhead, which can be seen from the reduction of its maximum equivalent stress by 21.2%, that of its maximum deformation by 0.75%, and that of its mass by 1.04%.

  5. Research Reactor Spent Fuel Transfer/Storage Cask with Application to TRIGA Fuel - Designed Cask Shielding Independent Evaluation

    International Nuclear Information System (INIS)

    Institute for Nuclear Research (INR) Pitesti owns and operates a TRIGA dual-core Research Reactor for material testing, power reactor fuel and nuclear safety studies (dual-core concept involves independent operation of TRIGA 14 MW Steady-State Reactor and TRIGA Annular-Core Pulsing Reactor at each end of a large pool). In May 2006, TRIGA 14 MW SSR core was fully converted to Low Enriched Uranium (LEU 20 wt% 235U) fuel, according to Reduced Enrichment for Research and Test Reactors agreements and current worldwide non-proliferation efforts. Paper presents a shielding independent evaluation applied to designed transfer/ storage cask for TRIGA INR spent fuel, a mandatory step in preparation of the documentation required for spent fuel transfer/storage cask authorisation process. Fuel elements irradiation was modelled by assuming constant power for entire residence time inside reactor core, for 14 MW reactor operation power and two different scenarios characteristic for accident calculations according to TRIGA 14 MW SSR safety report and reactor operation experience. The discharged spent LEU fuel was cooled down for 2 and 5 years, respectively. Source term assessment and spent fuel characteristic parameters estimation were done by means of ORIGEN-S burn-up code (included in Oak Ridge National Laboratory's SCALE6 package) with specific cross-sections libraries, updating data for each burn-up step. For the transfer/storage cask shielding analysis, two different cases have been considered, the main difference residing in TRIGA fuel elements loading. The radiation dose rates to the transfer/storage cask wall and in air at different distances from the cask have been estimated by means of MAVRIC/Monaco shielding 3D Monte Carlo code included in ORNL's SCALE6 package. (author)

  6. SOC-DS computer code provides tool for design evaluation of homogeneous two-material nuclear shield

    Science.gov (United States)

    Disney, R. K.; Ricks, L. O.

    1967-01-01

    SOC-DS Code /Shield Optimization Code-Direc Search/, selects a nuclear shield material of optimum volume, weight, or cost to meet the requirments of a given radiation dose rate or energy transmission constraint. It is applicable to evaluating neutron and gamma ray shields for all nuclear reactors.

  7. A1C Test

    Science.gov (United States)

    ... to minimize the complications caused by chronically elevated glucose levels, such as progressive damage to body organs like the kidneys, eyes, cardiovascular system, and nerves. The A1c test result ...

  8. Calculation of neutron and gamma ray energy spectra for fusion reactor shield design: comparison with experiment

    International Nuclear Information System (INIS)

    Integral experiments that measure the transport of approx. 14 MeV D-T neutrons through laminated slabs of proposed fusion reactor shield materials have been carried out. Measured and calculated neutron and gamma ray energy spectra are compared as a function of the thickness and composition of stainless steel type 304, borated polyethylene, and Hevimet (a tungsten alloy), and as a function of detector position behind these materials. The measured data were obtained using a NE-213 liquid scintillator using pulse-shape discrimination methods to resolve neutron and gamma ray pulse height data and spectral unfolding methods to convert these data to energy spectra. The calculated data were obtained using two-dimensional discrete ordinates radiation transport methods in a complex calculational network that takes into account the energy-angle dependence of the D-T neutrons and the nonphysical anomalies of the S/sub n/ method

  9. Characterization of Promiscuous Binding of Phosphor Ligands to Breast-Cancer-Gene 1 (BRCA1) C-Terminal (BRCT): Molecular Dynamics, Free Energy, Entropy and Inhibitor Design.

    Science.gov (United States)

    You, Wanli; Huang, Yu-Ming M; Kizhake, Smitha; Natarajan, Amarnath; Chang, Chia-En A

    2016-08-01

    Inhibition of the protein-protein interaction (PPI) mediated by breast-cancer-gene 1 C-terminal (BRCT) is an attractive strategy to sensitize breast and ovarian cancers to chemotherapeutic agents that induce DNA damage. Such inhibitors could also be used for studies to understand the role of this PPI in DNA damage response. However, design of BRCT inhibitors is challenging because of the inherent flexibility associated with this domain. Several studies identified short phosphopeptides as tight BRCT binders. Here we investigated the thermodynamic properties of 18 phosphopeptides or peptide with phosphate mimic and three compounds with phosphate groups binding to BRCT to understand promiscuous molecular recognition and guide inhibitor design. We performed molecular dynamics (MD) simulations to investigate the interactions between inhibitors and BRCT and their dynamic behavior in the free and bound states. MD simulations revealed the key role of loops in altering the shape and size of the binding site to fit various ligands. The mining minima (M2) method was used for calculating binding free energy to explore the driving forces and the fine balance between configuration entropy loss and enthalpy gain. We designed a rigidified ligand, which showed unfavorable experimental binding affinity due to weakened enthalpy. This was because it lacked the ability to rearrange itself upon binding. Investigation of another phosphate group containing compound, C1, suggested that the entropy loss can be reduced by preventing significant narrowing of the energy well and introducing multiple new compound conformations in the bound states. From our computations, we designed an analog of C1 that introduced new intermolecular interactions to strengthen attractions while maintaining small entropic penalty. This study shows that flexible compounds do not always encounter larger entropy penalty, compared with other more rigid binders, and highlights a new strategy for inhibitor design.

  10. Characterization of Promiscuous Binding of Phosphor Ligands to Breast-Cancer-Gene 1 (BRCA1) C-Terminal (BRCT): Molecular Dynamics, Free Energy, Entropy and Inhibitor Design

    Science.gov (United States)

    Huang, Yu-ming M.; Kizhake, Smitha; Natarajan, Amarnath; Chang, Chia-en A.

    2016-01-01

    Inhibition of the protein-protein interaction (PPI) mediated by breast-cancer-gene 1 C-terminal (BRCT) is an attractive strategy to sensitize breast and ovarian cancers to chemotherapeutic agents that induce DNA damage. Such inhibitors could also be used for studies to understand the role of this PPI in DNA damage response. However, design of BRCT inhibitors is challenging because of the inherent flexibility associated with this domain. Several studies identified short phosphopeptides as tight BRCT binders. Here we investigated the thermodynamic properties of 18 phosphopeptides or peptide with phosphate mimic and three compounds with phosphate groups binding to BRCT to understand promiscuous molecular recognition and guide inhibitor design. We performed molecular dynamics (MD) simulations to investigate the interactions between inhibitors and BRCT and their dynamic behavior in the free and bound states. MD simulations revealed the key role of loops in altering the shape and size of the binding site to fit various ligands. The mining minima (M2) method was used for calculating binding free energy to explore the driving forces and the fine balance between configuration entropy loss and enthalpy gain. We designed a rigidified ligand, which showed unfavorable experimental binding affinity due to weakened enthalpy. This was because it lacked the ability to rearrange itself upon binding. Investigation of another phosphate group containing compound, C1, suggested that the entropy loss can be reduced by preventing significant narrowing of the energy well and introducing multiple new compound conformations in the bound states. From our computations, we designed an analog of C1 that introduced new intermolecular interactions to strengthen attractions while maintaining small entropic penalty. This study shows that flexible compounds do not always encounter larger entropy penalty, compared with other more rigid binders, and highlights a new strategy for inhibitor design. PMID

  11. THE MECHANICAL AND SHIELDING DESIGN OF A PORTABLE SPECTROMETER AND BEAM DUMP ASSEMBLY AT BNLS ACCELERATOR TEST FACILITY.

    Energy Technology Data Exchange (ETDEWEB)

    HU,J.P.; CASEY,W.R.; HARDER,D.A.; PJEROV,S.; RAKOWSKY,G.; SKARITKA,J.R.

    2002-09-05

    A portable assembly containing a vertical-bend dipole magnet has been designed and installed immediately down-beam of the Compton electron-laser interaction chamber on beamline 1 of the Accelerator Test Facility (ATF) at Brookhaven National Laboratory (BNL). The water-cooled magnet designed with field strength of up to 0.7 Tesla will be used as a spectrometer in the Thompson scattering and vacuum acceleration experiments, where field-dependent electron scattering, beam focusing and energy spread will be analyzed. This magnet will deflect the ATF's 60 MeV electron-beam 90{sup o} downward, as a vertical beam dump for the Compton scattering experiment. The dipole magnet assembly is portable, and can be relocated to other beamlines at the ATF or other accelerator facilities to be used as a spectrometer or a beam dump. The mechanical and shielding calculations are presented in this paper. The structural rigidity and stability of the assembly were studied. A square lead shield surrounding the assembly's Faraday Cup was designed to attenuate the radiation emerging from the 1 inch-copper beam stop. All photons produced were assumed to be sufficiently energetic to generate photoneutrons. A safety evaluation of groundwater tritium contamination due to the thermal neutron capturing by the deuterium in water was performed, using updated Monte Carlo neutron-photon coupled transport code (MCNP). High-energy neutron spallation, which is a potential source to directly generate radioactive tritium and sodium-22 in soil, was conservatively assessed in verifying personal and environmental safety.

  12. Alternate shield material feasibility

    Energy Technology Data Exchange (ETDEWEB)

    Specht, E.R.; Levitt, L.B.

    1984-04-01

    The feasibility and cost/benefit of using materials other than stainless steel for in-vessel neutron shielding in large LMFBRs were investigated. Canned vibratorally compacted B/sub 4/C powder shields were found to be much more economical than stainless steel (a savings of $1.1M in loop plant designs and $9.4M in pool plant designs). The helium gas pressure buildup in B/sub 4/C shields placed around LMFBR in-vessel components (direct reactor heat exchangers in a loop reactor and intermediate heat exchangers in a pool reactor) would only be 0.04 atm after 40 y of reactor operation (with 80% dense powder). The irradiation-induced swelling of the B/sub 4/C would only be 0.002%. No adverse reactor impact would occur if the B/sub 4/C escaped from the B/sub 4/C shields.

  13. Alternate shield material feasibility

    International Nuclear Information System (INIS)

    The feasibility and cost/benefit of using materials other than stainless steel for in-vessel neutron shielding in large LMFBRs were investigated. Canned vibratorally compacted B4C powder shields were found to be much more economical than stainless steel (a savings of $1.1M in loop plant designs and $9.4M in pool plant designs). The helium gas pressure buildup in B4C shields placed around LMFBR in-vessel components (direct reactor heat exchangers in a loop reactor and intermediate heat exchangers in a pool reactor) would only be 0.04 atm after 40 y of reactor operation (with 80% dense powder). The irradiation-induced swelling of the B4C would only be 0.002%. No adverse reactor impact would occur if the B4C escaped from the B4C shields

  14. The influence of the lay-out of beam diagnostic elements on the shielding design at the Tesla accelerator installation

    International Nuclear Information System (INIS)

    A number of devices are routinely used for collimation and beam diagnostics at accelerator installations. Some of them permanently cuts-off parts of the accelerated particles forming a distinct beam shape (slits and diaphragms). Others are used from time to time to give information on beam shape or current by intercepting the beam (Faraday cups, scintillators, wire grids). Due to a number of nuclear reactions resulted by the interaction of energetic particles with matter, these devices are strong sources of ionizing radiation and they must be considered in the shielding design procedure. The fast neutron equivalent dose rate is calculated for a certain lay-out of beam diagnostic elements at the 'Tesla' Accelerator Installation and their contribution to the equivalent dose is discussed. (author)

  15. Shielding Effectiveness of Laminated Shields

    Directory of Open Access Journals (Sweden)

    B. P. Rao

    2008-12-01

    Full Text Available Shielding prevents coupling of undesired radiated electromagnetic energy into equipment otherwise susceptible to it. In view of this, some studies on shielding effectiveness of laminated shields with conductors and conductive polymers using plane-wave theory are carried out in this paper. The plane wave shielding effectiveness of new combination of these materials is evaluated as a function of frequency and thickness of material. Conductivity of the polymers, measured in previous investigations by the cavity perturbation technique, is used to compute the overall reflection and transmission coefficients of single and multiple layers of the polymers. With recent advances in synthesizing stable highly conductive polymers these lightweight mechanically strong materials appear to be viable alternatives to metals for EM1 shielding.

  16. Gamma dose rate calculations for conceptual design of a shield system for spent fuel interim dry storage in CNA 1

    International Nuclear Information System (INIS)

    After completing the rearrangement of the Spent Fuel Elements (SFE) into a compact arrangement in the two storage water pools, Atucha Nuclear Reactor 1 (ANR 1) will leave free position for the wet storage of the SFE discharged until December 2014. Even, in two possible scenarios, such as extending operation from 2015 or the cessation of operation after that date, it will be necessary to empty the interim storage water pools transferring the SFE to a temporary dry storage system. Because the law 25.018 'Management of Radioactive Wastes' implies for the first scenario - operation beyond 2015 - that Nucleoelectrica Argentina S.A. will still be in charge of the dry storage system and for the second - the cessation of operation after 2015 - the National Commission of Atomic Energy (CNEA) will be in charge by the National Management Program of Radioactive Wastes, the interim dry storage system of SNF is an issue of common interest which justifies go forward together. For that purpose and in accordance with the criticality and shielding calculations relevant to the project, in this paper we present the dose rate calculations for shielding conceptual design of a system for dry interim storage of the SFE of ANR 1. The specifications includes that the designed system must be suitable without modification for the SFE of the ANR 2. The results for the calculation of the photon dose rate, in touch and at one meter far, for the Transport Module and the Container of the SFE, are presented, which are required and controlled by the National Regulatory Authority (NRA) and the International Atomic Energy Agency (IAEA). It was used the SAS4 module of SCALE5.1 system and MCNP5. As a design tool for the photon shielding in order to meet current standards for allowable dose rates, a radial and axial parametric analysis were developed based on the thickness of lead of the Transport Module. The results were compared and verified between the two computing systems. Before this

  17. Scintillation counter, segmented shield

    International Nuclear Information System (INIS)

    A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

  18. Shielded syringe

    International Nuclear Information System (INIS)

    This patent specification relates to a partially disposable shielded syringe for injecting radioactive material into a patient. It is claimed that the technique overcomes the problems of non-standardisation of syringe size. (U.K.)

  19. Design, Progressive Modeling, Manufacture, and Testing of Composite Shield for Turbine Engine Blade Containment

    Science.gov (United States)

    Binienda, Wieslaw K.; Sancaktar, Erol; Roberts, Gary D. (Technical Monitor)

    2002-01-01

    An effective design methodology was established for composite jet engine containment structures. The methodology included the development of the full and reduced size prototypes, and FEA models of the containment structure, experimental and numerical examination of the modes of failure clue to turbine blade out event, identification of materials and design candidates for future industrial applications, and design and building of prototypes for testing and evaluation purposes.

  20. Designer's guidebook for first wall/blanket/shield assembly, maintenance, and repair

    International Nuclear Information System (INIS)

    This is the initial issue of the guidebook. Since a guidebook of this type must incorporate information concerning a wide range of subjects, much additional data will eventually be included. The guidebook will document, in summary and easily referenceable form, data, designs, design concepts, design guidelines and background information useful to the FWBS and to the Maintenance System designer. In providing guidelines for the AMR of the FWBS, the guidebook must, of necessity, include guidelines for all aspects of maintenance associated with the FWBS. These include most maintenance operations within the reactor room necessary to gain access, identify faults, and handle equipment related to FWBS maintenance. In addition, the guidelines include those required to define facility requirements for handling and repair of FWBS and related reactor components external to the reactor room. Particular emphasis is given to remote maintenance design and operations

  1. Designer's guidebook for first wall/blanket/shield assembly, maintenance, and repair

    Energy Technology Data Exchange (ETDEWEB)

    1983-12-30

    This is the initial issue of the guidebook. Since a guidebook of this type must incorporate information concerning a wide range of subjects, much additional data will eventually be included. The guidebook will document, in summary and easily referenceable form, data, designs, design concepts, design guidelines and background information useful to the FWBS and to the Maintenance System designer. In providing guidelines for the AMR of the FWBS, the guidebook must, of necessity, include guidelines for all aspects of maintenance associated with the FWBS. These include most maintenance operations within the reactor room necessary to gain access, identify faults, and handle equipment related to FWBS maintenance. In addition, the guidelines include those required to define facility requirements for handling and repair of FWBS and related reactor components external to the reactor room. Particular emphasis is given to remote maintenance design and operations.

  2. Design and characterization of a novel neutron shield for BNCT in an experimental model of oral cancer in the hamster cheek pouch at RA-3

    International Nuclear Information System (INIS)

    Our research group at the Radiation Pathology Division of the Department of Radiobiology (National Atomic Energy Commission) has previously demonstrated the therapeutic efficacy of different BNCT protocols to treat oral cancer in an experimental hamster cheek pouch model. In particular, to perform studies in this experimental model at the thermal facility constructed at RA-3, we designed and constructed a shielding device for thermal neutrons, to be able to expose the cheek pouch while minimizing the dose to the rest of the body. This device allowed for the irradiation of one animal at a time. Given the usage rate of the device, the aim of the present study was to design and construct an optimized version of the existing shielding device that would allow for the simultaneous irradiation of 2 animals at the thermal facility of RA-3. Taking into account the characteristics of the neutron source and preliminary biological assays, we designed the shielding device for the body of the animal, i.e. a rectangular shaped box with double acrylic walls. The space between the walls contains a continuous filling of 6Li2CO3 (95% enriched in 6Li), approximately 6 mm thick. Two small windows interrupt the shield at one end of the box through which the right pouch of each hamster is everted out onto an external acrylic shelf for exposure to the neutron flux. The characterization of the shielding device showed that the neutron flux was equivalent at both irradiation positions confirming that we were able to design and construct a new shielding device that allows for the irradiation of 2 animals at the same time at the thermal facility of RA-3. This new version of the shielding device will reduce the number of interventions of the reactor operators, reducing occupational exposure to radiation and will make the procedure more efficient for researchers. In addition, we addressed the generation of tritium as a product of the capture reaction in lithium. It was considered as a potential

  3. Shield For Flexible Pipe

    Science.gov (United States)

    Ponton, Michael K.; Williford, Clifford B.; Lagen, Nicholas T.

    1995-01-01

    Cylindrical shield designed to fit around flexible pipe to protect nearby workers from injury and equipment from damage if pipe ruptures. Designed as pressure-relief device. Absorbs impact of debris ejected radially from broken flexible pipe. Also redirects flow of pressurized fluid escaping from broken pipe onto flow path allowing for relief of pressure while minimizing potential for harm.

  4. Design and applications of an anticoincidence shielded low background gamma-ray spectrometer

    International Nuclear Information System (INIS)

    A low background gamma-ray spectrometer has been constructed for measuring artificial and natural radioative isotopes. The design of the spectrometer, its properties and the application to the determination of natural radioactivity of dental ceramics are described. (orig.)

  5. Size Design of CdZnTe Detector Shield for Measuring Burnup of Spent Fuel

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>It is important to measure the burnup of spent fuel for nuclear safeguards, burnup credit and critical safety in spent-fuel reprocessing process. The purpose of this work is designing a portable device to

  6. Design and applications of an anticoincidence shielded low background gamma-ray spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Petri, H. [Forschungszentrum Juelich GmbH (Germany). Zentralabteilung fuer Chemische Analysen

    1997-03-01

    A low background gamma-ray spectrometer has been constructed for measuring artificial and natural radioative isotopes. The design of the spectrometer, its properties and the application to the determination of natural radioactivity of dental ceramics are described. (orig.)

  7. WE-G-17A-09: Novel Magnetic Shielding Design for Inline and Perpendicular Integrated 6 MV Linac and 1.0 T MRI Systems

    Energy Technology Data Exchange (ETDEWEB)

    Li, X; Ma, B; Kuang, Y [University of Nevada, Las Vegas, Las Vegas, NV (United States); Diao, X [Shenzhen University, Shenzhen, Guangdong (China)

    2014-06-15

    Purpose: The influence of fringe magnetic fields delivered by magnetic resonance imaging (MRI) on the beam generation and transportation in Linac is still a major challenge for the integration of linear accelerator and MRI (Linac-MRI). In this study, we investigated an optimal magnetic shielding design for Linac-MRI and further characterized the beam trajectory in electron gun. Methods: Both inline and perpendicular configurations were analyzed in this study. The configurations, comprising a Linac-MRI with a 100cm SAD and an open 1.0 T superconductive magnet, were simulated by the 3D finite element method (FEM). The steel shielding around the Linac was included in the 3D model, the thickness of which was varied from 1mm to 20mm, and magnetic field maps were acquired with and without additional shielding. The treatment beam trajectory in electron gun was evaluated using OPERA 3d SCALA with and without shielding cases. Results: When Linac was not shielded, the uniformity of diameter sphere volume (DSV) (30cm) was about 5 parts per million (ppm) and the fringe magnetic fields in electron gun were more than 0.3 T. With shielding, the magnetic fields in electron gun were reduced to less than 0.01 T. For the inline configuration, the radial magnetic fields in the Linac were about 0.02T. A cylinder steel shield used (5mm thick) altered the uniformity of DSV to 1000 ppm. For the perpendicular configuration, the Linac transverse magnetic fields were more than 0.3T, which altered the beam trajectory significantly. A 8mm-thick cylinder steel shield surrounding the Linac was used to compensate the output losses of Linac, which shifted the magnetic fields' uniformity of DSV to 400 ppm. Conclusion: For both configurations, the Linac shielding was used to ensure normal operation of the Linac. The effect of magnetic fields on the uniformity of DSV could be modulated by the shimming technique of the MRI magnet. NIH/NIGMS grant U54 GM104944, Lincy Endowed Assistant

  8. WE-G-17A-09: Novel Magnetic Shielding Design for Inline and Perpendicular Integrated 6 MV Linac and 1.0 T MRI Systems

    International Nuclear Information System (INIS)

    Purpose: The influence of fringe magnetic fields delivered by magnetic resonance imaging (MRI) on the beam generation and transportation in Linac is still a major challenge for the integration of linear accelerator and MRI (Linac-MRI). In this study, we investigated an optimal magnetic shielding design for Linac-MRI and further characterized the beam trajectory in electron gun. Methods: Both inline and perpendicular configurations were analyzed in this study. The configurations, comprising a Linac-MRI with a 100cm SAD and an open 1.0 T superconductive magnet, were simulated by the 3D finite element method (FEM). The steel shielding around the Linac was included in the 3D model, the thickness of which was varied from 1mm to 20mm, and magnetic field maps were acquired with and without additional shielding. The treatment beam trajectory in electron gun was evaluated using OPERA 3d SCALA with and without shielding cases. Results: When Linac was not shielded, the uniformity of diameter sphere volume (DSV) (30cm) was about 5 parts per million (ppm) and the fringe magnetic fields in electron gun were more than 0.3 T. With shielding, the magnetic fields in electron gun were reduced to less than 0.01 T. For the inline configuration, the radial magnetic fields in the Linac were about 0.02T. A cylinder steel shield used (5mm thick) altered the uniformity of DSV to 1000 ppm. For the perpendicular configuration, the Linac transverse magnetic fields were more than 0.3T, which altered the beam trajectory significantly. A 8mm-thick cylinder steel shield surrounding the Linac was used to compensate the output losses of Linac, which shifted the magnetic fields' uniformity of DSV to 400 ppm. Conclusion: For both configurations, the Linac shielding was used to ensure normal operation of the Linac. The effect of magnetic fields on the uniformity of DSV could be modulated by the shimming technique of the MRI magnet. NIH/NIGMS grant U54 GM104944, Lincy Endowed Assistant

  9. Conductor backed and shielded multi-layer coplanar waveguide designs on LTCC for RF carrier boards for packaging PICs

    Science.gov (United States)

    Marraccini, Philip J.; Jezzini, Moises A.; Peters, Frank H.

    2016-05-01

    Designing photonic integrated circuits (PICs) with packaging in mind is important since this impacts the performance of the final product. In coherent optical communication applications there are a large number of DC and RF lines that need routed to connect the PIC to the outer packaging. These RF lines should be impedance matched to the devices, isolated from each other, low loss and protected against electromagnetic interference (EMI) over the frequency range of interest to achieve the performance required for the application. Multilevel low temperature co-fired ceramic (LTCC) boards can be used as a carrier board connecting the PIC to the packaging due to its good RF performance, machinability, compatibility with hermetic sealing, and ability to integrate drivers into the board. Flexibility with layer numbers enables additional layers for shielding against electromagnetic interference or increased space for routing electrical connections. In this paper the design, simulations, and measured results for a set of 4 phase matched transmission lines in LTCC that would be used with an IQ MZM are presented. The measured 3dB bandwidth for a set of four phase matched transmission lines for an IQ MZM was measured to be 19.8 GHz.

  10. Material characterisation and preliminary mechanical design for the HL-LHC shielded beam screens operating at cryogenic temperatures

    CERN Document Server

    Garion, C; Koettig, T; Machiocha, W; Morrone, M

    2015-01-01

    The High Luminosity LHC project (HL-LHC) aims at increasing the luminosity (rate of collisions) in the Large Hadron Collider (LHC) experiments by a factor of 10 beyond the original design value (from 300 to 3000 fb-1). It relies on new superconducting magnets, installed close to the interaction points, equipped with new beam screen. This component has to ensure the vacuum performance together with shielding the cold mass from physics debris and screening the cold bore cryogenic system from beam induced heating. The beam screen operates in the range 40-60 K whereas the magnet cold bore temperature is 1.9 K. A tungsten-based material is used to absorb the energy of particles. In this paper, measurements of the mechanical and physical properties of such tungsten material are shown at room and cryogenic temperature. In addition, the design and the thermal mechanical behaviour of the beam screen assembly are presented also. They include the heat transfer from the tungsten absorbers to the cooling pipes and the sup...

  11. Drip Shield Emplacement Gantry Concept

    Energy Technology Data Exchange (ETDEWEB)

    Silva, R.A.; Cron, J.

    2000-03-29

    This design analysis has shown that, on a conceptual level, the emplacement of drip shields is feasible with current technology and equipment. A plan for drip shield emplacement was presented using a Drip Shield Transporter, a Drip Shield Emplacement Gantry, a locomotive, and a Drip Shield Gantry Carrier. The use of a Drip Shield Emplacement Gantry as an emplacement concept results in a system that is simple, reliable, and interfaces with the numerous other exising repository systems. Using the Waste Emplacement/Retrieval System design as a basis for the drip shield emplacement concept proved to simplify the system by using existing equipment, such as the gantry carrier, locomotive, Electrical and Control systems, and many other systems, structures, and components. Restricted working envelopes for the Drip Shield Emplacement System require further consideration and must be addressed to show that the emplacement operations can be performed as the repository design evolves. Section 6.1 describes how the Drip Shield Emplacement System may use existing equipment. Depending on the length of time between the conclusion of waste emplacement and the commencement of drip shield emplacement, this equipment could include the locomotives, the gantry carrier, and the electrical, control, and rail systems. If the exisiting equipment is selected for use in the Drip Shield Emplacement System, then the length of time after the final stages of waste emplacement and start of drip shield emplacement may pose a concern for the life cycle of the system (e.g., reliability, maintainability, availability, etc.). Further investigation should be performed to consider the use of existing equipment for drip shield emplacement operations. Further investigation will also be needed regarding the interfaces and heat transfer and thermal effects aspects. The conceptual design also requires further design development. Although the findings of this analysis are accurate for the assumptions made

  12. Design of the Fifth-Generation Target-Moderator-Reflector-Shield Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Nowicki, Suzanne Florence [Los Alamos National Lab. (LANL), Los Alamos, NM (United Sta; Mocko, Michal [Los Alamos National Lab. (LANL), Los Alamos, NM (United Sta

    2015-11-16

    The facilities at the Los Alamos Neutron Science Center are described first. The target is being redesigned so that the Flight Paths (FP) in the upper tier provide a higher intensity in the epithermal and medium energy range. It is found that a 3-piece design looks promising: intensity in epithermal and medium energy range in upper tier is an order of magnitude higher than current Mark III, and intensity in the thermal energy range is higher in the lower tier than current Mark III. Time emission spectra show a bump due to the scattering of fast neutrons. Other investigations such as the addition of wings around the upper target will be conducted.

  13. Cryogenic Design of a Large Superconducting Magnet for Astro-particle Shielding on Deep Space Travel Missions

    Science.gov (United States)

    Bruce, Romain; Baudouy, Bertrand

    The Space Radiation Superconducting Shield (SR2S) European project aims at studying a large superconducting toroid magnet to protect the human habitat from the ionizing radiations coming from Galactic Cosmic Ray during long term missions in deep space. Titanium clad MgB2 conductor is used to afford a bending power greater than 5 T.m at 10 K. A specific cryogenic design is needed to cool down this 10 m long and 12.8 m in diameter magnet. A passive cooling system, using a V-groove sunshield, is considered to reduce the heat flux coming from the Sun or Mars. An active configuration, using pulse tube cryocoolers, will be linked to the 80 K thermal screen intercepting most of the heat fluxes coming from the human habitat. The toroid magnet will be connected also to cryocoolers to absorb the few watts reaching its surface. Two kinds of thermal link are being considered to absorb the heat on the 80 K thermal screen. The first one is active, with a pump circulating helium gas in a network of exchange tubes. The second one is passive using long cryogenic pulse heat pipe (PHP) with the evaporator on the surface of the thermal screen and the condenser attached to the pulse tube.

  14. Design and construction of a shield for the 9" x 9" NaI(Tl well-type detector

    Directory of Open Access Journals (Sweden)

    Hansman Jan

    2014-01-01

    Full Text Available This paper describes a homemade lead, 15 cm-thick, cylindrical shaped shield of a 9" x 9" NaI(Tl gamma spectrometric well-type detector. Commercially available lead was melted into cylindrical rings. The molds for the cylindrical rings were made from hard-cooked beech wood which was pressed in a sand mold to make the final mold. After cooling, the lead rings and ring edges were sanded, transported from the foundry to the laboratory of the Department of Physics in Novi Sad, Serbia, and assembled in the detector shield. The total mass of the shield is 2622 kg. Some lines inside the shield are reduced almost 200 times and the total count rate (280 keV-3000 keV is reduced 132.7 times.

  15. Design of boron carbide-shielded irradiation channel of the outer irradiation channel of the Ghana Research Reactor-1 using MCNP.

    Science.gov (United States)

    Abrefah, R G; Sogbadji, R B M; Ampomah-Amoako, E; Birikorang, S A; Odoi, H C; Nyarko, B J B

    2011-01-01

    The MCNP model for the Ghana Research Reactor-1 was redesigned to incorporate a boron carbide-shielded irradiation channel in one of the outer irradiation channels. Extensive investigations were made before arriving at the final design of only one boron carbide covered outer irradiation channel; as all the other designs that were considered did not give desirable results of neutronic performance. The concept of redesigning a new MCNP model, which has a boron carbide-shielded channel is to equip the Ghana Research Reactor-1 with the means of performing efficient epithermal neutron activation analysis. After the simulation, a comparison of the results from the original MCNP model for the Ghana Research Reactor-1 and the new redesigned model of the boron carbide shielded channel was made. The final effective criticality of the original MCNP model for the GHARR-1 was recorded as 1.00402 while that of the new boron carbide designed model was recorded as 1.00282. Also, a final prompt neutron lifetime of 1.5245 × 10(-4)s was recorded for the new boron carbide designed model while a value of 1.5571 × 10(-7)s was recorded for the original MCNP design of the GHARR-1.

  16. 3-dimensional shielding design for a spallation neutron source facility in the high-intensity proton accelerator project

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Masaya; Maekawa, Fujio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Evaluation of shielding performance for a 1 MW spallation neutron source facility in the Materials and Life Science Facility being constructed in the High-Intensity Proton Accelerator Project (J-PARC) is important from a viewpoint of radiation safety and optimization of arrangement of components. This report describes evaluated results for the shielding performance with modeling three-dimensionally whole structural components including gaps between them in detail. A Monte Carlo calculation method with MCNPX2.2.6 code and LA-150 library was adopted. Streaming and void effects, optimization of shield for cost reduction and optimization of arrangement of structures such as shutters were investigated. The streaming effects were investigated quantitatively by changing the detailed structure of components and gap widths built into the calculation model. Horizontal required shield thicknesses were ranged from about 6.5 m to 7.5 m as a function of neutron beam line angles. A shutter mechanism for a horizontal neutron reflectometer that was directed downward was devised, and it was shown that the shielding performance of the shutter was acceptable. An optimal biological shield configuration was finally determined according to the calculated results. (author)

  17. Ulexite-galena intermediate-weight concrete as a novel design for overcoming space and weight limitations in the construction of efficient shields against neutrons and photons.

    Science.gov (United States)

    Aghamiri, S M R; Mortazavi, S M J; Razi, Z; Mosleh-Shirazi, M A; Baradaran-Ghahfarokhi, M; Rahmani, F; Faeghi, F

    2013-01-01

    Recently, due to space and weight limitations, scientists have tried to design and produce concrete shields with increased attenuation of radiation but not increased mass density. Over the past years, the authors' had focused on the production of heavy concrete for radiation shielding, but this is the first experience of producing intermediate-weight concrete. In this study, ulexite (hydrated sodium calcium borate hydroxide) and galena (lead ore) have been used for the production of a special intermediate-weight concrete. Shielding properties of this intermediate-weight concrete against photons have been investigated by exposing the samples to narrow and broad beams of gamma rays emitted from a ⁶⁰Co radiotherapy unit. Densities of the intermediate-weight concrete samples ranged 3.64-3.90 g cm⁻³, based on the proportion of the ulexite in the mix design. The narrow-beam half-value layer (HVL) of the ulexite-galena concrete samples for 1.25 MeV ⁶⁰Co gamma rays was 2.84 cm, much less than that of ordinary concrete (6.0 cm). The Monte Carlo (MC) code MCNP4C was also used to model the attenuation of ⁶⁰Co gamma-ray photons and Am-Be neutrons of the ulexite-galena concrete with different thicknesses. The ⁶⁰Co HVL calculated by MCNP simulation was 2.87 cm, indicating a good agreement between experimental measurements and MC simulation. Furthermore, MC-calculated results showed that thick ulexite-galena concrete shields (60-cm thickness) had a 7.22 times (722 %) greater neutron attenuation compared with ordinary concrete. The intermediate-weight ulexite-galena concrete manufactured in this study may have many important applications in the construction of radiation shields with weight limitations such as the swing or sliding doors that are currently used for radiotherapy treatment rooms. PMID:23019599

  18. Mechanical shielded hot cell

    International Nuclear Information System (INIS)

    A plan to erect a mechanical shielded hot cell in the process hall of the Radiochemical Laboratory at Inchas is described. The hot cell is designed for safe handling of spent fuel bundles, from the Inchas reactor, and for dismantling and cutting the fuel rods in preparation for subsequent treatment. The biological shielding allows for the safe handling of a total radioactivity level up to 10,000 MeV-Ci. The hot cell consists of an α-tight stainless-steel box, connected to a γ-shielded SAS, through an air-lock containing a movable carriage. The α-box is tightly connected with six dry-storage cavities for adequate storage of the spent fuel bundles. Both the α-box, with the dry-storage cavities, and the SAS are surrounded by 200-mm thick biological lead shielding. The α-box is equipped with two master-slave manipulators, a lead-glass window, a monorail crane and Padirac and Minirag systems. The SAS is equipped with a lead-glass window, tong manipulator, a shielded pit and a mechanism for the entry of the spent fuel bundle. The hot cell is served by adequate ventilation and monitoring systems. (author)

  19. Optimized design of shields for diagnostic X rays with NCRP 147 technique; Diseno optimizado de blindajes para rayos X diagnostico con tecnica NCRP 147

    Energy Technology Data Exchange (ETDEWEB)

    Gama T, G. [Calidad XXI SA de CV, Zacatecas 67-007 Col. Roma, 06700 Mexico D.F. (Mexico)]. e-mail: cxxi@prodigy.net.mx

    2006-07-01

    A comparison among the design techniques of shielding for X-ray diagnostic rooms with the NCRP 49 (1976) report technique, AAPM 39 (1993) Y the one of the NCRP 147 (2005) technique. The designs correspond to a room of conventional X-rays, one of fluoroscopy, one of tomography Y one of mammography. In all the cases it demonstrates that the NCRP 49 technique overestimate the shieldings. The causes of the overestimation of the NCRP 49 can be attributed to: a) high values of the work charge that don't consider the spectral fluence of the photons that are present in each room, b) to the differences in the values of the kerma in air without attenuation for the dispersed primary radiation Y of leakage among both reports. (Author)

  20. Biological Shielding Design Effectiveness of the Brachytherapy Unit at the Korle Bu Teaching Hospital in Ghana Using Mcnp5 Monte Carlo Code

    Directory of Open Access Journals (Sweden)

    C.C. Arwui

    2011-05-01

    Full Text Available Design objectives for brachytherapy treatment facilities require sufficient shielding to reduce primary and scatter radiation to design limit in order to limit exposure to patients, staff and the general public. The primary aim of this study is to verify whether shielding of the brachytherapy unit at the Korle Bu teaching Hospital in Ghana provides adequate protection in order to assess any radiological health and safety impact and also test the suitability of other available sources. The study evaluates the effectiveness of the biological shielding design of a Cs-137 brachytherapy unit at the Korle-Bu Teaching Hospital in Ghana using MCNP5. The facility was modeled based on the design specifications for LDR Cs-137, MDR Cs-137, HDR Co-60 and HDR Ir-192 treatment modalities. The estimated dose rate ranged from (0.01-0.15 μSv/h and (0.37-3.05 μSv/h for the existing initial and decayed activities of LDR Cs-137 for the public and controlled areas respectively, (0.03-0.57 μSv/h and (1.53-8.06 μSv/h for MDR Cs-137, (7.47-59.46 μSv/h and (144.87-178.74 μSv/h for HDR Co- 60, (0.13-6.95 μSv/h and (19.47-242.98 μSv/h for HDR Ir-192 for the public and controlled areas respectively. The results were verified by dose rates measurement for the current LDR setup at the Brachytherapy unit and agreed quiet well. It was also compared with the reference values of 0.5 μSv/h for public areas and 7.5 μSv/h for controlled areas respectively. It can be concluded that the shielding is adequate for the existing source.

  1. A new design of a lead-acrylic shield for staff dose reduction in radial and femoral access coronary catheterization

    International Nuclear Information System (INIS)

    Today's standard radiation protection during coronary angiography and percutaneous coronary interventions is the combined use of lead acrylic shields and table-mounted lower body protection. Ambient dose measurements, however, have shown that these protection devices need improvement. Using an anthropomorphic physical phantom, various scenarios were investigated with respect to personnel exposure: (a) enlarging the shield (b) adding a flexible protective curtain to the bottom side of the shield, and (c) application of radioprotective patient drapes. For visualization of the dose reduction effect, Monte Carlo simulations were performed. The flexible curtain in contact with the patient's body reduces the ambient dose rate at the operator's position by up to (87.5 % ± 7.1) compared to the situation with the bare shield. The use of both the flexible curtain and the patient drape reduces the ambient dose rate by up to (90.8 % ± 7). Similar results were achieved for the assisting personnel when they were positioned next to the operator. In addition, the enlarged shield provides better protection of the head region of tall operators. Adding a flexible protective curtain to the bottom side of the shield can protect operators from high doses, especially for body parts which are not protected by lead aprons, e.g. head, and eye lenses. This may be important with respect to lower dose limits for eye lenses in future. The protective effect in real-life working conditions is still being evaluated in an ongoing clinical study.

  2. A new design of a lead-acrylic shield for staff dose reduction in radial and femoral access coronary catheterization

    Energy Technology Data Exchange (ETDEWEB)

    Eder, H. [Deptartment of Radiation Protection (Germany); Seidenbusch, M.C.; Treitl, M. [Muenchen Univ. Clinical Center (Germany). Inst. for Clinical Radiology; Gilligan, P. [Mater Private Hospital, Dublin (Ireland). Medical Physics

    2015-10-15

    Today's standard radiation protection during coronary angiography and percutaneous coronary interventions is the combined use of lead acrylic shields and table-mounted lower body protection. Ambient dose measurements, however, have shown that these protection devices need improvement. Using an anthropomorphic physical phantom, various scenarios were investigated with respect to personnel exposure: (a) enlarging the shield (b) adding a flexible protective curtain to the bottom side of the shield, and (c) application of radioprotective patient drapes. For visualization of the dose reduction effect, Monte Carlo simulations were performed. The flexible curtain in contact with the patient's body reduces the ambient dose rate at the operator's position by up to (87.5 % ± 7.1) compared to the situation with the bare shield. The use of both the flexible curtain and the patient drape reduces the ambient dose rate by up to (90.8 % ± 7). Similar results were achieved for the assisting personnel when they were positioned next to the operator. In addition, the enlarged shield provides better protection of the head region of tall operators. Adding a flexible protective curtain to the bottom side of the shield can protect operators from high doses, especially for body parts which are not protected by lead aprons, e.g. head, and eye lenses. This may be important with respect to lower dose limits for eye lenses in future. The protective effect in real-life working conditions is still being evaluated in an ongoing clinical study.

  3. Design and performance characteristics of an electromagnetic interference shielded enclosure for high voltage Pockels cell switching system

    Indian Academy of Sciences (India)

    A K Sharma; K K Mishra; M Raghuramaiah; P A Naik; P D Gupta

    2007-06-01

    An electro-magnetic interference noise shielding enclosure for Pockels cells for high speed synchronized switching has been set-up and tested. The shielding effectiveness of the aluminum enclosures housing the Pockels cells and the electronic circuitry has been measured using a high impedance probe and is found to be $\\sim 50 dB$. This ensures a noise-free and synchronized electro-optic switching in an Nd:glass re-generative amplifier of chirped pulse amplification based table top terawatt laser system.

  4. Designing of epoxy composites reinforced with carbon nanotubes grown carbon fiber fabric for improved electromagnetic interference shielding

    Science.gov (United States)

    Singh, B. P.; Choudhary, Veena; Saini, Parveen; Mathur, R. B.

    2012-06-01

    In this letter, we report preparation of strongly anchored multiwall carbon nanotubes (MWCNTs) carbon fiber (CF) fabric preforms. These preforms were reinforced in epoxy resin to make multi scale composites for microwave absorption in the X-band (8.2-12.4GHz). The incorporation of MWCNTs on the carbon fabric produced a significant enhancement in the electromagnetic interference shielding effectiveness (EMI-SE) from -29.4 dB for CF/epoxy-composite to -51.1 dB for CF-MWCNT/epoxy multiscale composites of 2 mm thickness. In addition to enhanced EMI-SE, interlaminar shear strength improved from 23 MPa for CF/epoxy-composites to 50 MPa for multiscale composites indicating their usefulness for making structurally strong microwave shields.

  5. Designing of epoxy composites reinforced with carbon nanotubes grown carbon fiber fabric for improved electromagnetic interference shielding

    Directory of Open Access Journals (Sweden)

    B. P. Singh

    2012-06-01

    Full Text Available In this letter, we report preparation of strongly anchored multiwall carbon nanotubes (MWCNTs carbon fiber (CF fabric preforms. These preforms were reinforced in epoxy resin to make multi scale composites for microwave absorption in the X-band (8.2-12.4GHz. The incorporation of MWCNTs on the carbon fabric produced a significant enhancement in the electromagnetic interference shielding effectiveness (EMI-SE from −29.4 dB for CF/epoxy-composite to −51.1 dB for CF-MWCNT/epoxy multiscale composites of 2 mm thickness. In addition to enhanced EMI-SE, interlaminar shear strength improved from 23 MPa for CF/epoxy-composites to 50 MPa for multiscale composites indicating their usefulness for making structurally strong microwave shields.

  6. Tower Shielding Reactor II design and operation report. Vol. 3. Assembling and testing of the control mechanism assembly

    International Nuclear Information System (INIS)

    The mechanisms that are operated to control the reactivity of the Tower Shielding Reactor II(TSR-II) are mounted on a Control Mechanism Housing (CMH) that is centered inside the reactor core. The information required to procure, fabricate, inspect, and assemble a CMH is contained in the ORNL engineering drawings listed in the appropriate sections. The components are fabricated and inspected from these drawings in accordance with a Quality Assurance Plan and a Manufacturing Plan. The material in this report describes the acceptance and performance tests of CMH subassemblies used ty the Tower Shielding Facility (TSF) staff but it can also be used by personnel fabricating the components. This information which was developed and used before the advent of the formalized QA Program and Manufacturing Plans evolved during the fabrication and testing of the first five CMHs

  7. BUMPERII - DESIGN ANALYSIS CODE FOR OPTIMIZING SPACECRAFT SHIELDING AND WALL CONFIGURATION FOR ORBITAL DEBRIS AND METEOROID IMPACTS

    Science.gov (United States)

    Hill, S. A.

    1994-01-01

    BUMPERII is a modular program package employing a numerical solution technique to calculate a spacecraft's probability of no penetration (PNP) from man-made orbital debris or meteoroid impacts. The solution equation used to calculate the PNP is based on the Poisson distribution model for similar analysis of smaller craft, but reflects the more rigorous mathematical modeling of spacecraft geometry, orientation, and impact characteristics necessary for treatment of larger structures such as space station components. The technique considers the spacecraft surface in terms of a series of flat plate elements. It divides the threat environment into a number of finite cases, then evaluates each element of each threat. The code allows for impact shielding (shadowing) of one element by another in various configurations over the spacecraft exterior, and also allows for the effects of changing spacecraft flight orientation and attitude. Four main modules comprise the overall BUMPERII package: GEOMETRY, RESPONSE, SHIELD, and CONTOUR. The GEOMETRY module accepts user-generated finite element model (FEM) representations of the spacecraft geometry and creates geometry databases for both meteoroid and debris analysis. The GEOMETRY module expects input to be in either SUPERTAB Universal File Format or PATRAN Neutral File Format. The RESPONSE module creates wall penetration response databases, one for meteoroid analysis and one for debris analysis, for up to 100 unique wall configurations. This module also creates a file containing critical diameter as a function of impact velocity and impact angle for each wall configuration. The SHIELD module calculates the PNP for the modeled structure given exposure time, operating altitude, element ID ranges, and the data from the RESPONSE and GEOMETRY databases. The results appear in a summary file. SHIELD will also determine the effective area of the components and the overall model, and it can produce a data file containing the probability

  8. Shielding synchrotron light sources: Advantages of circular shield walls tunnels

    Science.gov (United States)

    Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.

    2016-08-01

    Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produce significantly higher neutron component dose to the experimental floor than lower energy injection and ramped operations. High energy neutrons produced in the forward direction from thin target beam losses are a major component of the dose rate outside the shield walls of the tunnel. The convention has been to provide thicker 90° ratchet walls to reduce this dose to the beam line users. We present an alternate circular shield wall design, which naturally and cost effectively increases the path length for this forward radiation in the shield wall and thereby substantially decreasing the dose rate for these beam losses. This shield wall design will greatly reduce the dose rate to the users working near the front end optical components but will challenge the beam line designers to effectively utilize the longer length of beam line penetration in the shield wall. Additional advantages of the circular shield wall tunnel are that it's simpler to construct, allows greater access to the insertion devices and the upstream in tunnel beam line components, as well as reducing the volume of concrete and therefore the cost of the shield wall.

  9. Spacecraft Electrostatic Radiation Shielding

    Science.gov (United States)

    2008-01-01

    This project analyzed the feasibility of placing an electrostatic field around a spacecraft to provide a shield against radiation. The concept was originally proposed in the 1960s and tested on a spacecraft by the Soviet Union in the 1970s. Such tests and analyses showed that this concept is not only feasible but operational. The problem though is that most of this work was aimed at protection from 10- to 100-MeV radiation. We now appreciate that the real problem is 1- to 2-GeV radiation. So, the question is one of scaling, in both energy and size. Can electrostatic shielding be made to work at these high energy levels and can it protect an entire vehicle? After significant analysis and consideration, an electrostatic shield configuration was proposed. The selected architecture was a torus, charged to a high negative voltage, surrounding the vehicle, and a set of positively charged spheres. Van de Graaff generators were proposed as the mechanism to move charge from the vehicle to the torus to generate the fields necessary to protect the spacecraft. This design minimized complexity, residual charge, and structural forces and resolved several concerns raised during the internal critical review. But, it still is not clear if such a system is costeffective or feasible, even though several studies have indicated usefulness for radiation protection at energies lower than that of the galactic cosmic rays. Constructing such a system will require power supplies that can generate voltages 10 times that of the state of the art. Of more concern is the difficulty of maintaining the proper net charge on the entire structure and ensuring that its interaction with solar wind will not cause rapid discharge. Yet, if these concerns can be resolved, such a scheme may provide significant radiation shielding to future vehicles, without the excessive weight or complexity of other active shielding techniques.

  10. Radiation shielding for neutron guides

    Energy Technology Data Exchange (ETDEWEB)

    Ersez, T. [Reactor Operations, ANSTO, PMB 1, Menai, NSW 2234 (Australia)]. E-mail: tez@ansto.gov.au; Braoudakis, G. [Reactor Operations, ANSTO, PMB 1, Menai, NSW 2234 (Australia); Osborn, J.C. [Reactor Operations, ANSTO, PMB 1, Menai, NSW 2234 (Australia)

    2006-11-15

    Models of the neutron guide shielding for the out of bunker guides on the thermal and cold neutron beam lines of the OPAL Reactor (ANSTO) were constructed using the Monte Carlo code MCNP 4B. The neutrons that were not reflected inside the guides but were absorbed by the supermirror (SM) layers were noted to be a significant source of gammas. Gammas also arise from neutrons absorbed by the B, Si, Na and K contained in the glass. The proposed shielding design has produced compact shielding assemblies. These arrangements are consistent with safety requirements, floor load limits, and cost constraints. To verify the design a prototype was assembled consisting of 120 mm thick Pb(96%)Sb(4%) walls resting on a concrete block. There was good agreement between experimental measurements and calculated dose rates for bulk shield regions.

  11. Design on Electromagnetic Shielding for a Sealed Communication Terminal%一种密封通信终端的电磁屏蔽设计

    Institute of Scientific and Technical Information of China (English)

    吴迪; 高驰名; 马建章

    2015-01-01

    电磁干扰严重影响着密封终端技术性能的有效发挥,电磁屏蔽是提高电子系统和电子设备电磁兼容性能力的重要措施之一。简要介绍了典型通信终端的结构形式,分析了密封通信终端电磁屏蔽设计所面临的问题,指出了影响设备电磁屏蔽效能的泄露源。以典型密封通信终端设备为实例,在不改变或降低密设备封性能的情况下,针对连接器、开关、指示灯孔、显示屏窗口、键盘开口和盒体缝隙等不同的结构特点进行电磁屏蔽设计,给出了具体的设计思路和方法。经电磁兼容测试验证,该设计方法是科学、有效的。%The electromagnetic interference(EMI)has a strong impact on the technology performance of sealed terminal.The elec⁃tromagnetic shielding is one of the important measures of raising electromagnetic compatibility of electronic system and electronic equip⁃ment.This paper introduces briefly the structure of a typical sealed communication terminal,analyzes the problems in electromagnetic shielding design of sealed communication terminals,and also points out the leak source that impacts the electromagnetic shielding effi⁃ciency of terminals.Taking a typical sealed communication terminal as an example,the electromagnetic shielding design is performed aiming at different structural characteristics of connector,switch,indicator hole,screen,keyboard interface,power connector and switch without sealing capability changing and reducing,and the typical design idea and method are proposed.The electromagnetic compatibility test results show that this design method is scientific and available.

  12. 多气氛焊接操作系统的设计%The Design of Welding and Melting Container with Multifunction Shielding Gas Environment

    Institute of Scientific and Technical Information of China (English)

    徐兴文; 耿德军; 李志

    2011-01-01

    对焊接中多种气体保护问题进行探讨.通过单室设计方案解决教学与科研中多种气体保护气氛的问题.实现了系统软、硬件设计方案.利用计算机进行了系统的管理、故障报警与数据采集、整理与分析.该系统能降低贵金属的消耗,增强熔炼与焊接效果.%Several types of shielding gas environment in the welding process is discussed.The design of one container is used for solving the lack of several types of shielding gas in teaching and researching. The design of hardware and software systems is realized. The monitoring management of the system, fault alarm , technological parameter and statistical analysis are implemented. The design has a lower consumption of material and more effective technology of welding and melting.

  13. Designing of shielding and collimator for high-energy X-ray beam: application to 3 MV Tandem Pelletron based HEX-ray spectrometry

    International Nuclear Information System (INIS)

    High-energy X-rays (60-1000 keV) or HEX-ray bear unique advantage over conventional X-rays in the field of diffraction and scattering experiments. HEX-ray is an important experimental technique because of its uniqueness to characterize technically challenging samples (liquids, glass, amorphous materials, nanomaterial, thick samples, etc.). In the present paper detail designing of the lead collimator and shielding for the recently developed HEX-Ray spectrometry experiment using characteristic PbK-lines (75-85 keV) emitted due to bombardment of 3 MeV proton beam generated from the Pelletron accelerator has been reported. Attenuation (%), transmission (%), and energy absorption (%) are calculated using the NIST data which is based on X-ray interaction cross sections and material densities. Thickness for Pb-shielding possessing highest attenuation (99.99%) for 75 keV and 85 keV X-rays are 3 mm and 4 mm respectively. Hence, shielding thickness about 5 mm is used to cover the experimental table. Again, introducing a source collimator (diameter = 8 mm, length = 35 mm) between the X-ray target (source) and the sample, the incoherent scattered radiation due to air in the path of the beam and the multiple reflection from the chamber as well as from the detector inserting tube can be suppressed. An extra energetic and intense X-ray line was observed at about 44.5 keV using a high-purity germanium (HpGe) detector (Detector Systems GmbH (DSG), Germany). This contamination line is not an escape peak (PbKGeK) and can be suppressed using 8 mm Pb-collimator between X-ray target and sample. The details of the designing, experimental setup, and its applications are discussed in the full paper.

  14. The Load Design and Implementation of HJ-1-C Space-borne SAR%HJ-1-C卫星合成孔径雷达载荷的设计与实现

    Institute of Scientific and Technical Information of China (English)

    禹卫东; 杨汝良; 邓云凯; 赵凤军; 雷宏

    2014-01-01

    HJ-1-C is a Synthetic Aperture Radar (SAR) satellite in the Constellation of “2+1” for China environment and disaster monitoring. It works at S-band with a resolution of 5 m. SAR payload uses a reflector antenna and a high-power concentrated transmitter. Its light weight and high efficiency is very suitable for a small satellite platform. Now HJ-1-C satellite has been launched into orbit and has acquired Chinese first S-band SAR images from space, which demonstrate excellent quality and rich information about scenes imaged. This success verifies our design, testing and experiment work on the payload. With its following operation, HJ-1-C satellite is expected to make a great contribution to the applications of environment protection and disaster monitoring in China. This paper introduces the design and development of HJ-1-C SAR payload, present its main parameters and performance, describes its device details and its manufacture, testing and experiment process. Some images acquired in the orbit are showed.%HJ-1-C 是我国环境与灾害监测小卫星“2+1”星座中的一颗合成孔径雷达(SAR)卫星,工作于 S 波段,具有5 m分辨率。SAR载荷采用网状反射面天线和大功率放大器方案,具有重量轻、效率高的特点,适合于小卫星平台。目前HJ-1-C卫星已在轨运行,获得我国首批S波段星载SAR图像,图像质量高,地物信息丰富,表明SAR 载荷的设计合理,试验和测试充分。HJ-1-C 卫星将为我国减灾和环境应用发展做出贡献。该文将对 HJ-1-C卫星SAR载荷的设计和研制进行全面介绍,包括其主要功能和技术指标,各部分的设计,以及研制、测试和试验工程,最后给出其在轨获得的图像。

  15. Designing of epoxy composites reinforced with carbon nanotubes grown carbon fiber fabric for improved electromagnetic interference shielding

    OpenAIRE

    Singh, B. P.; Veena Choudhary; Parveen Saini; Mathur, R.B.

    2012-01-01

    In this letter, we report preparation of strongly anchored multiwall carbon nanotubes (MWCNTs) carbon fiber (CF) fabric preforms. These preforms were reinforced in epoxy resin to make multi scale composites for microwave absorption in the X-band (8.2-12.4GHz). The incorporation of MWCNTs on the carbon fabric produced a significant enhancement in the electromagnetic interference shielding effectiveness (EMI-SE) from −29.4 dB for CF/epoxy-composite to −51.1 dB for CF-MWCNT/epoxy multiscale comp...

  16. Performance test on shielding concrete

    International Nuclear Information System (INIS)

    The cylinder of the shielding concrete is made from common Portland cement and home-made coarse or fine aggregates. Orthogonal design experiment and regression analysis are adopted to study the effects of the water content, sand percentage and water-cement ratio on the property of shielding concrete and the difference between them. The test shows that the tensile strength is in inverse proportion with water-cement ratio, and the influence is quite significant. Another factor is the type of aggregates. The effect of the age on its density is not obvious. Similarly, the concrete shielding γ rays shares the same influencing factors with that shielding neutron rays on density, slump and tensile strength. And both have the same change rules regarding to mechanical property. (authors)

  17. Shielding integrity testing of radioactive material transport packaging

    International Nuclear Information System (INIS)

    Although this Code of Practice is intended primarily to cover shielding integrity test requirements for off-site shielded radioactive material transport packaging, it may also be partly applicable to containers and specialised handling equipment (e.g. fuelling machines) used only on site, and to radiation shielding generally. The code is not concerned with proving adequacy of shielding design or with its absolute shielding value. (author)

  18. Performance of the improved version of Monte Carlo Code A{sup 3}MCNP for cask shielding design

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, T. [Mitsubishi Heavy Industries, Yokohama (Japan); Ueki, K. [Tokai Univ., Kanagawa (Japan); Sato, O. [Mitsubishi Research Inst., Tokyo (Japan); Sjoden, G.E. [Dept. of Nuclear and Radiological Engineering, Univ. of Florida, Gainesville, FL (United States); Miyake, Y.; Ohmura, M.; Haghighat, A.

    2004-07-01

    A{sup 3}MCNP (Automatic Adjoint Accelerated MCNP) is a revised version of the MCNP Monte Carlo code, that automatically prepares variance reduction parameters for the CADIS (Consistent Adjoint Driven Importance Sampling) methodology. Using a deterministic ''importance'' (or adjoint) function, CADIS performs source and transport biasing within the weight-window technique. The current version of A{sup 3}MCNP uses the 3-D Sn transport TORT code to determine a 3-D importance function distribution. Based on simulation of several real-life problems, it is demonstrated that A3MCNP provides precise calculation results with a remarkably short computation time by using the proper and objective variance reduction parameters. However, since the first version of A{sup 3}MCNP provided only a point source configuration option for large-scale shielding problems, such as spent-fuel transport casks, a large amount of memory may be necessary to store enough points to properly represent the source. Hence, we have developed an improved version of A{sup 3}MCNP (referred to as A{sup 3}MCNPV) which has a volumetric source configuration option. This paper describes the successful use of A{sup 3}MCNPV for cask neutron and gamma-ray shielding problem.

  19. Shielding design of a treatment room for an accelerator-based epithermal neutron irradiation facility for BNCT

    International Nuclear Information System (INIS)

    Protecting the facility personnel and the general public from radiation exposure is a primary safety concern of an accelerator-based epithermal neutron irradiation facility. This work makes an attempt at answering the questions open-quotes How much?close quotes and open-quotes What kind?close quotes of shielding will meet the occupational limits of such a facility. Shielding effectiveness is compared for ordinary and barytes concretes in combination with and without borated polyethylene. A calculational model was developed of a treatment room, patient open-quotes scatterer,close quotes and the epithermal neutron beam. The Monte Carlo code, MCNP, was used to compute the total effective dose equivalent rates at specific points of interest outside of the treatment room. A conservative occupational effective dose rate limit of 0.01 mSv h-1 was the guideline for this study. Conservative Monte Carlo calculations show that constructing the treatment room walls with 1.5 m of ordinary concrete, 1.2 m of barytes concrete, 1.0 m of ordinary concrete preceded by 10 cm of 5% boron-polyethylene, or 0.8 m of barytes concrete preceded by 10 cm of 5% boron-polyethylene will adequately protect facility personnel. 20 refs., 8 figs., 2 tabs

  20. Corrugation Stuffed Shield for Spacecraft and Its Performance

    Institute of Scientific and Technical Information of China (English)

    LIU You-ying; WANG Hai-fu

    2006-01-01

    A corrugation stuffed shield system protecting spacecrafts against meteoroid and orbital debris (M/OD) is presented. The semi-empirical ballistic limit equations (BLEs)defining the protection capability of the shield system are given, an d the shielding performance is also discussed. The corrugation stuffed shield (CSS) is more effective than stuffed Whipple shield for M/OD protection,and its shielding performance will be improved significantly as increasing the impact angle. Orbital debris up to 1cm in diameter can be shielded effectively as increasing the impact angle to 25° at the corrugated angle of 30°. The results are significant to spacecraft design.

  1. Designing Shelter in New Buildings. A Manual for Architects on the Preliminary Designing of Shielding from Fallout Gamma Radiation in Normally Functioning Spaces in New Buildings.

    Science.gov (United States)

    Knott, Albert

    Analysis of radiation fallout prevention factors in new construction is presented with emphasis on architectural shielding principles. Numerous diagrams and charts illustrate--(1) radiation and fallout properties, (2) building protection principles, (3) details and planning suggestions, and (4) tabular data interpretation. A series of charts is…

  2. AN INNOVATION DESIGN OF ORE HEATING FURNACE WATER-COOLING SHIELD%矿热炉水冷保护屏的新设计

    Institute of Scientific and Technical Information of China (English)

    温新民

    2014-01-01

    In the new design , the materials of water-cooling shield include boiler steel , stainless steel and pure copper that is changed from forged copper plate , its manufacturing process is cold bending and welding of boiler steel and stainless steel , and upward casting of pure copper for the main part of the shield which is changed from machining and welding of forged copper plate , the hung parts and water in-let ( or outlet ) parts are welded to the main part .Pure copper has good heat conductivity , magnetic isola-tion and corrosion resistance , can lower its temperature effectively , and greatly improve its service life . The shield has highly recovery value that can reduce reinvestment cost remarkably .As a result, the pro-motion of the new method has a bright future .%水冷保护屏的材质由锅炉钢、不锈钢、锻造铜板改为纯铜;工艺由锅炉钢、不锈钢板冷弯、焊接,锻造铜板的机械加工、焊接制造改为主体部分用电解铜材料上引铸造;悬挂和水口零件部分与主体焊接。利用纯铜材质的高效导热率、隔磁性、耐腐蚀性,有效地降低自身的温度,使用寿命大大提高。并且废旧的保护屏回收价值很高,可大大降低二次投资成本,值得推广。

  3. Design of a Laboratory Hall Thruster with Magnetically Shielded Channel Walls, Phase III: Comparison of Theory with Experiment

    Science.gov (United States)

    Mikellides, Ioannis G.; Katz, Ira; Hofer, Richard R.; Goebel, Dan M.

    2012-01-01

    A proof-of-principle effort to demonstrate a technique by which erosion of the acceleration channel in Hall thrusters of the magnetic-layer type can be eliminated has been completed. The first principles of the technique, now known as "magnetic shielding," were derived based on the findings of numerical simulations in 2-D axisymmetric geometry. The simulations, in turn, guided the modification of an existing 6-kW laboratory Hall thruster. This magnetically shielded (MS) thruster was then built and tested. Because neither theory nor experiment alone can validate fully the first principles of the technique, the objective of the 2-yr effort was twofold: (1) to demonstrate in the laboratory that the erosion rates can be reduced by >order of magnitude, and (2) to demonstrate that the near-wall plasma properties can be altered according to the theoretical predictions. This paper concludes the demonstration of magnetic shielding by reporting on a wide range of comparisons between results from numerical simulations and laboratory diagnostics. Collectively, we find that the comparisons validate the theory. Near the walls of the MS thruster, theory and experiment agree: (1) the plasma potential has been sustained at values near the discharge voltage, and (2) the electron temperature has been lowered by at least 2.5-3 times compared to the unshielded (US) thruster. Also, based on carbon deposition measurements, the erosion rates at the inner and outer walls of the MS thruster are found to be lower by at least 2300 and 1875 times, respectively. Erosion was so low along these walls that the rates were below the resolution of the profilometer. Using a sputtering yield model with an energy threshold of 25 V, the simulations predict a reduction of 600 at the MS inner wall. At the outer wall ion energies are computed to be below 25 V, for which case we set the erosion to zero in the simulations. When a 50-V threshold is used the computed ion energies are below the threshold at both

  4. Calculation And Design Of A New Configuration For Radiation Shielding At Neutron Beam No.3 For Fundamental And Applied Researches

    International Nuclear Information System (INIS)

    The tangential horizontal channel of No. 3 of the Dalat Research Reactor has been opened and used during the 1990s. The utilizations of the thermal neutron beam at this channel were the Neutron Radiography and the Prompt Gamma Neutron Activation Analysis method (PGNAA). At present, the neutron beam used for nuclear structure data researches based on the Summing of Amplitude Coincident Pulses system (SACP). Beside, several related research equipments have been set up and operated for the research purposes. A renovation of the neutron channel, therefore, will play an important role in safe and effective utilizations of the neutron beam in fields of nuclear physic training and researches. A new configuration for radiation shielding has been simulated by MCNP code. The calculated results of dose rates for neutron and gamma at working positions are in range of dose rate limit. (author)

  5. A Study on the Radiation Source Effect to the Radiation Shielding Analysis for a Spent-Fuel Cask Design with Burnup-Credit

    International Nuclear Information System (INIS)

    The radiation shielding analysis for a Burnup-credit (BUC) cask designed under the management of Korea Radioactive Waste Management Corporation (KRMC) was performed to examine the contribution of each radiation source affecting dose rate distribution around the cask. Various radiation sources, which contain neutron and gamma-ray sources placed in active fuel region and the activation source, and imaginary nuclear fuel were all considered in the MCNP calculation model to realistically simulate the actual situations. It was found that the maximum external and surface dose rates of the spent fuel cask were satisfied with the domestic standards both in normal and accident conditions. In normal condition, the radiation dose rate distribution around the cask was mainly influenced by activation source (60 Co radioisotope); in another case, the neutron emitted in active fuel region contributed about 90% to external dose rate at 1m distance from side surface of the cask. Besides, the contribution level of activation source was dramatically increased to the dose rates in top and bottom regions of the cask. From this study, it was recognized that the detailed investigation on the radiation sources should be performed conservatively and accurately in the process of radiation shielding analysis for a BUC cask.

  6. 电子设备机箱电磁屏蔽分析和设计%Electronic Equipment Chassis Electromagnetic Shielding Analysis and Design

    Institute of Scientific and Technical Information of China (English)

    赵旭阳

    2012-01-01

    On the analysis of the electronic equipment working environment,and on the basis of the electronic equipment of external clear main interference source,and shielding effectiveness analysis.For improving Electronic Equipments' resist-disturbance capability,contraposing outside interference source,advance shielding filtering and ground and otherwise resist-disturbance design method,to insure Electronic Equipments can be working up to snuff in the condition of complex execrable war field EME.%在分析了电子设备工作环境的基础上,明确了电子设备外部的主要干扰源,并进行了屏蔽效能分析。为提高电子设备抗干扰性能,针对外部干扰源提出了屏蔽、滤波和接地等抗干扰设计方案,确保电子设备能在复杂恶劣的环境下正常工作。

  7. Design of Shield Machine's Cutter-head Used in Soft Soil%软土盾构机的刀盘设计与选型

    Institute of Scientific and Technical Information of China (English)

    郑国强

    2014-01-01

    介绍了软土盾构机刀盘的结构设计、刀具的选型及特点、刀具的布置方式及影响因素;并采用ANSYS软件对刀盘进行了有限元分析,以提高盾构机刀盘设计的可靠性。%In this paper ,the structural design and characteristics of shield machine's cutter-head used in soft soil were introduced ,and the type-selecting and arrangement of cutters were described .The ANSYS software was applied to the simulation analysis of the cut-ter-head ,and the cutter-head's reliability was improved .

  8. Radiation Shielding for Nuclear Thermal Propulsion

    Science.gov (United States)

    Caffrey, Jarvis A.

    2016-01-01

    Design and analysis of radiation shielding for nuclear thermal propulsion has continued at Marshall Space Flight Center. A set of optimization tools are in development, and strategies for shielding optimization will be discussed. Considerations for the concurrent design of internal and external shielding are likely required for a mass optimal shield design. The task of reducing radiation dose to crew from a nuclear engine is considered to be less challenging than the task of thermal mitigation for cryogenic propellant, especially considering the likely implementation of additional crew shielding for protection from solar particles and cosmic rays. Further consideration is thus made for the thermal effects of radiation absorption in cryogenic propellant. Materials challenges and possible methods of manufacturing are also discussed.

  9. A1C Test and Diabetes

    Science.gov (United States)

    ... Prediabetes The A1C Test and Diabetes The A1C Test and Diabetes What is the A1C test? The A1C test is a blood test that ... management and diabetes research. How does the A1C test work? The A1C test is based on the ...

  10. Study on shielding design method of radiation streaming in a tokamak-type DT fusion reactor based on Monte Carlo calculation

    International Nuclear Information System (INIS)

    In tokamak-type DT nuclear fusion reactor, there are various type slits and ducts in the blanket and the vacuum vessel. The helium production in the rewelding location of the blanket and the vacuum vessel, the nuclear properties in the super-conductive TF coil, e.g. the nuclear heating rate in the coil winding pack, are enhanced by the radiation streaming through the slits and ducts, and they are critical concern in the shielding design. The decay gamma ray dose rate around the duct penetrating the blanket and the vacuum vessel is also enhanced by the radiation streaming through the duct, and they are also critical concern from the view point of the human access to the cryostat during maintenance. In order to evaluate these nuclear properties with good accuracy, three dimensional Monte Carlo calculation is required but requires long calculation time. Therefore, the development of the effective simple design evaluation method for radiation streaming is substantially important. This study aims to establish the systematic evaluation method for the nuclear properties of the blanket, the vacuum vessel and the Toroidal Field (TF) coil taking into account the radiation streaming through various types of slits and ducts, based on three dimensional Monte Carlo calculation using the MNCP code, and for the decay gamma ray dose rates penetrated around the ducts. The present thesis describes three topics in five chapters as follows; 1) In Chapter 2, the results calculated by the Monte Carlo code, MCNP, are compared with those by the Sn code, DOT3.5, for the radiation streaming in the tokamak-type nuclear fusion reactor, for validating the results of the Sn calculation. From this comparison, the uncertainties of the Sn calculation results coming from the ray-effect and the effect due to approximation of the geometry are investigated whether the two dimensional Sn calculation can be applied instead of the Monte Carlo calculation. Through the study, it can be concluded that the

  11. Handout on shielding calculation

    International Nuclear Information System (INIS)

    In order to avoid the difficulties of the radioprotection supervisors in the tasks related to shielding calculations, is presented in this paper the basic concepts of shielding theory. It also includes exercises and examples. (author)

  12. Electromagnetically shielded building

    International Nuclear Information System (INIS)

    This invention relates to a building having an electromagnetic shield structure well-suited for application to an information network system utilizing electromagnetic waves, and more particularly to an electromagnetically shielded building for enhancing the electromagnetic shielding performance of an external wall. 6 figs

  13. Design key points of shield tunnel applied in the water intake & drain project of power plants%电厂取排水工程采用盾构法隧道的设计要点

    Institute of Scientific and Technical Information of China (English)

    庄敏

    2014-01-01

    In this paper, the design key points of shield tunnel applied in the water intake&drain project of power plants are summarized according to the design code.These design key points will be references for engineers.%根据规范的要求,整理出盾构法隧道应用于电厂取排水工程的设计要点,供同仁设计参考。

  14. Results of shielding characteristics tests in Monju

    Energy Technology Data Exchange (ETDEWEB)

    Usami, Shin; Suzuoki, Zenro; Deshimaru, Takehide; Nakashima, Fumiaki [Japan Nuclear Cycle Development Inst., Tsuruga, Fukui (Japan)

    2001-06-01

    In the prototype fast breeder reactor Monju, the shielding characteristics tests were made around the reactor core, the primary heat transport system, and the fuel handling and storage system as a part of the system start-up tests from 0% to 45% of rated power from October 1993 through December 1995. The results of the measurements, analyses and evaluations in these tests validated the FBR shielding analysis methods and demonstrated that there was a safe shielding design margin in Monju. The important basic data for use in future FBR shielding design were successfully acquired. In order to obtain more substantial basic data and to improve the accuracy of the analyses, the next shielding measurements are planned for the period of the system start-up tests at the restart of Monju. (author)

  15. ANS shielding standards for light-water reactors

    International Nuclear Information System (INIS)

    The purpose of the American Nuclear Society Standards Subcommittee, ANS-6, Radiation Protection and Shielding, is to develop standards for radiation protection and shield design, to provide shielding information to other standards-writing groups, and to develop standard reference shielding data and test problems. A total of seven published ANS-6 standards are now current. Additional projects of the subcommittee, now composed of nine working groups, include: standard reference data for multigroup cross sections, gamma-ray absorption coefficients and buildup factors, additional benchwork problems for shielding problems and energy spectrum unfolding, power plant zoning design for normal and accident conditions, process radiation monitors, and design for postaccident radiological conditions

  16. Rotating shielded crane system

    Science.gov (United States)

    Commander, John C.

    1988-01-01

    A rotating, radiation shielded crane system for use in a high radiation test cell, comprises a radiation shielding wall, a cylindrical ceiling made of radiation shielding material and a rotatable crane disposed above the ceiling. The ceiling rests on an annular ledge intergrally attached to the inner surface of the shielding wall. Removable plugs in the ceiling provide access for the crane from the top of the ceiling into the test cell. A seal is provided at the interface between the inner surface of the shielding wall and the ceiling.

  17. The ITER EC H and CD upper launcher: Design, analysis and testing of a bolted joint for the Blanket Shield Module

    Energy Technology Data Exchange (ETDEWEB)

    Gessner, Robby, E-mail: robby.gessner@kit.edu [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, D-76021 Karlsruhe (Germany); Aiello, Gaetano; Grossetti, Giovanni; Meier, Andreas [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, D-76021 Karlsruhe (Germany); Ronden, Dennis [DIFFER – Dutch Institute for Fundamental Energy Physics, P.O. Box 1207, NL-3430 BE Nieuwegein (Netherlands); Spaeh, Peter; Scherer, Theo; Schreck, Sabine; Strauss, Dirk; Vaccaro, Alessandro [Karlsruhe Institute of Technology, Institute for Applied Materials, P.O. Box 3640, D-76021 Karlsruhe (Germany)

    2013-10-15

    Highlights: ► The BSM of the ECH Launcher is attached to the Launcher Main Frame by a bolted joint. ► The bolts were designed as “captive” in order to avoid their accidental removal from the joint. ► The bolted flange connection using two sets of 15 captive bolts (M22 × 2) placed along the sides. ► The captive bolt design is based on a concept that uses a dedicated spring ring, a standard spiral spring and a tensioning screw with two threads to secure the bolts in a form-locking stop. -- Abstract: The final design of the structural system for the ITER EC H and CD upper launcher is in progress. Many design features of the preliminary design are under revision with the aim to achieve the built-to-print-status. This paper deals with design and analysis of a bolted joint for the Blanket Shield Module with special perspective on Remote Handling capability. The BSM of the ECH Launcher is attached to the Launcher Main Frame by a bolted joint conceived so that in the Hot Cell Facility, RH maintenance can be performed on internal components. The joint must be capable to resist very high Electro-Magnetic loads from disruptions, while it has to sustain substantial thermal cycling during operation. Thus the need for a rigid and reliable design is essential. Beside the set of pre-stressed bolts the flanges were therefore equipped with additional shear keys to divert radial moments away from the bolts. Main focus of the work performed was the mechanical design of the joint and the assessment of the structural integrity with respect to the loads applied and its capability for maintenance by RH procedures. To fulfill a major aspect of the RH requirements, the bolts were designed as “captive” in order to avoid their accidental removal from the joint. The captive bolt design is based on a concept that uses a dedicated spring ring, a standard spiral spring and a tensioning screw with two threads to secure the bolts in a form-locking stop. The final approval phase of

  18. Design of MP3 Player Based on AT89C51SND1C Microcontroller%AT89C51SND1C单片机的 MP3播放器设计

    Institute of Scientific and Technical Information of China (English)

    徐阳; 徐爱钧

    2015-01-01

    A MP3 player design scheme based on 51 microcontroller is proposed after analyzing the working principle and system compo‐sition of the portable MP3 player .The design uses the AT89C51SND1C microcontroller as the MP3 decoder ,the K9F1208 flash as exter‐nal memory ,the CS4330 as the sound playing circuit .The music file can be downloaded from PC through USB interface of the player .The scheme is simple ,cost‐effective ,low power consumption and easy to expand .%首先分析了便携式M P3播放器的工作原理及其系统构成,接着介绍了一种基于51单片机的M P3播放器设计方案。采用AT89C51SND1C单片机,其片内集成了 MP3解码器,使用 K9F1208闪存作为外存储器,放音电路采用CS4330,音乐文件通过播放器上的U SB接口从PC机上直接下载。该方案设计简单,性价比高、低功耗、易扩展。

  19. ITER blanket, shield and material data base

    International Nuclear Information System (INIS)

    As part of the summary of the Conceptual Design Activities (CDA) for the International Thermonuclear Experimental Reactor (ITER), this document describes the ITER blanket, shield, and material data base. Part A, ''ITER Blanket and Shield Conceptual Design'', discusses the need for ITER of a tritium breeding blanket to supply most of the tritium for the fuel cycle of the device. Blanket and shield combined must be designed to operate at a neutron wall loading of 1MW/m2, and to provide adequate shielding of the magnets to meet the neutron energy fluence goal of 3MWa/m2 at the first wall. After a summary of the conceptual design, the following topics are elaborated upon: (1) function, design requirement, and critical issues; (2) material selection; (3) blanket and shield segmentation; (4) blanket design description; (5) design analysis; (6) shield; (7) radiation streaming analysis; and (8) a summary of benchmark calculations. Part B, ''ITER Materials Evaluation and Data Base'', treats the compilation and assessment of the available materials data base used for the selection of the appropriate materials for all major components of ITER, including (i) structural materials for the first wall, (ii) Tritium breeding materials for the blanket, (iii) plasma facing materials for the divertor and first wall armor, and (4) electric insulators for use in the blanket and divertor. Refs, figs and tabs

  20. A study on the shielding mechanisms of SOI pixel detector

    CERN Document Server

    Lu, Yunpeng; Wu, Zhigang; Ouyang, Qun; Arai, Yasuo

    2015-01-01

    In order to tackle the charge injection issue that had perplexed the counting type SOI pixel for years, two successive chips CPIXTEG3 and CPIXTEG3b were developed utilizing two shielding mechanisms, Nested-well and Double-SOI, in the LAPIS process. A TCAD simulation showed the shielding effectiveness influenced by the high sheet resistance of shielding layers. Test structures specially designed to measure the crosstalk associated to charge injection were implemented in CPIXTEG3/3b. Measurement results proved that using shielding layer is indispensable for counting type pixel and Double-SOI is superior to Nested-well in terms of shielding effectiveness and design flexibility.

  1. Measurement of shielding characteristics in the prototype FBR Monju

    Energy Technology Data Exchange (ETDEWEB)

    Usami, Shin; Sasaki, Kenji; Deshimaru, Takehide; Nakashima, Fumiaki [Japan Nuclear Cycle Development Institute, Tsuruga, Fukui (Japan)

    2000-03-01

    In the prototype fast breeder reactor Monju, shielding measurements were made around the reactor core, the primary heat transport system (PHTS), and the fuel handling and storage system during the system start-up tests at different power levels between 0% and 45%. The objectives of the tests were to evaluate the margins by which the shielding performance exceeds the original design requirements, to demonstrate the validity of the shielding analysis method, and to acquire basic data for use in future FBR design. This paper summarizes the important features of the Monju shielding structures and the shielding measurement. (author)

  2. Under the Rape Shield

    OpenAIRE

    Roman, Denise

    2011-01-01

    This article focuses on the Rape Shield Laws and their evolution in the United States, one of the pioneers in this field. The article also discusses constitutional and feminist critiques of present Rape Shield Laws, and ends with a comparative perspective throughout the Anglo-American legal space today. Finally, although the Rape Shield Laws can be approached from a variety of discourses, this article engages specifically with a discourse that intersects legal and feminist analyses.

  3. Optimal Shielding for Minimum Materials Cost of Mass

    Energy Technology Data Exchange (ETDEWEB)

    Woolley, Robert D. [PPPL

    2014-08-01

    Material costs dominate some shielding design problems. This is certainly the case for manned nuclear power space applications for which shielding is essential and the cost of launching by rocket from earth is high. In such situations or in those where shielding volume or mass is constrained, it is important to optimize the design. Although trial and error synthesis methods may succeed a more systematic approach is warranted. Design automation may also potentially reduce engineering costs.

  4. Design of a PET/CT facility considering the shielding calculation in accordance with AAPM TG-108; Diseno de una instalacion PET/CT considerando el calculo de blindaje segun AAPM TG-108

    Energy Technology Data Exchange (ETDEWEB)

    Guevara R, V. Y.; Romero C, N. [Empresa QC DOSE S. A. C., Av. Tomas Marsano 1915, Surquillo, Lima 34 (Peru); Berrocal T, M., E-mail: vguevara@qcdose.com [Universidad Nacional Mayor de San Marcos, C. German Amezaga 375, Edif. Jorge Basadre, Ciudad Universitaria, Lima 1 (Peru)

    2014-08-15

    A Positron Emission Tomography / Computed Tomography facility may require protection barriers on floor, ceiling and walls, because the patient becomes a radioactive source that emits photons of 0.511 MeV, after having received a radiopharmaceutical, usually F-18 fluorodeoxyglucose (F-18 FDG). This work has as objective to propose the design of a PET/CT facility, taking into account technical and radiation protection considerations applied internationally, and also develop the necessary shielding for such installation by applying as published by the American Association of Physicists in Medicine Task Group Report 108. A shielding spreadsheet in Excel program was developed with reference to the recommendations of the AAPM TG - 08, to determine the shielding required for the walls, floor and ceiling. For fixing the radiation levels in the shielding calculation has been considered the actual restrictions for the occupationally exposed personnel (100 μSv/week) as well as the people in general (20 μSv/ week). The radiopharmaceutical used as a reference for the shielding calculation was the F-18 FDG. With the assistance of an architectural plan were determined distances from potential sources of radiation in facility (uptake and image acquisition living rooms) to points of interest around them. Finally the thickness of the protective barriers in lead and concrete necessary to achieve the established radiation levels were calculated and these results were stored in a table. This paper shows that technical aspects considered in the design of the installation and environments distribution can improve work processes within the PET/CT facility, consequently resulting in a reduction of the dose levels for people in general. (author)

  5. 某医院介入诊疗机房的屏蔽设计及防护效果验证%Verification on shielding design and radiation protection effect of interventional diagnosis and therapy machine room in a hospital

    Institute of Scientific and Technical Information of China (English)

    程晋鹏

    2013-01-01

    [Objective] To discuss the method for verifying the radiation protection effect of shielding design of the interventional diagnosis and therapy machine room,provide an access to put completion acceptance of radiation protective facilities into effect.[Methods] The shielding design of an interventional diagnosis and therapy machine room was verified and assessed by field investigation,theoretical estimate and sites measurement.[Results]The shielding material was reasonable for to this project.The radiation exposure levels of 21 monitoring sites around the room ranged between 0.02 and 0.20 μGy/h.However,the shielding design values of the walls were higher than theoretical count value of the same walls by 2-3 mm lead equivalent.[Conclusion] The total radiation protection effect of shielding design of the room is good.The combination of the above methods can effectively verify the radiation protection effect of shielding design.%目的 探讨介入诊疗机房屏蔽设计效果的验证办法,以利于放射防护设施竣工验收工作的实施.方法 通过现场调查、理论估算、现场检测等对某介入诊疗机房的屏蔽设计进行核实和评价.结果 屏蔽材料选用合理.机房周围21个检测位置的辐射水平均在0.02~0.20 μGy/h范围内.但机房四周墙体的屏蔽设计值均高出理论计算值约二三毫米铅当量.结论 该机房的屏蔽设计总体防护效果良好,上述几种方法的综合应用可较好地核实介入诊疗项目屏蔽设计,验证其防护效果.

  6. 一种紧凑型星球表面反应堆辐射屏蔽初步设计%A Preliminary Design of a Compact Radiation Shielding of Fission Surface Power Reactor

    Institute of Scientific and Technical Information of China (English)

    宋旺旺; 杜金峰; 赖万昌; 梁文峰

    2015-01-01

    针对美国星球表面裂变能源( FSP)概念方案中的辐射屏蔽问题进行了数值模拟,提出一种更为紧凑的屏蔽体结构。参照FSP系统的堆芯参数,对堆芯进行了均匀化处理,得到堆芯泄漏能谱及泄漏中子与泄漏光子的平均能量,考察了相关屏蔽材料在此能量下的衰减系数,通过改变屏蔽体整体构型、屏蔽体内部材料排序方式及其厚度,设计出更为优化的屏蔽体。%Aiming at the radiation shielding problems of the Fission Surface Power ( FSP) conceptual,this article has carried on some simulations and proposed a more compact shielding structure.The core is omogenized which is based on FSP′s core parameters to get the average leakage energy of neutrons and photons.The related shiel-ding materials′attenuation coefficiences under this energy are Examined.A more optimized shielding structure is design by changing the overall size and each material's thickness and sorting ways.

  7. 3,4-二氢吡咯[2,1-c][1,4](噁)嗪-1-酮及其7-芳酰基衍生物的设计与合成%Design and Synthesis of 3, 4-Dihydropyrrolo[2, 1-c][1,4]oxazin-1-one and Its 7-Acyl Derivatives

    Institute of Scientific and Technical Information of China (English)

    魏玮; KHAN Ali Yousaf; 郭永恩; 石乐君

    2009-01-01

    以2-吡咯基三氯乙酮为主要原料,经过乙二醇单酯化、羟基氯取代、环合三步反应制得了3,4-二氢吡咯[2,1-c][1,4](噁)嗪-1-酮;又经过Friedel-Crafts酰基化和环合反应制得了未见文献报道的7-芳酰基-3,4-二氢吡咯[2,1-c][1,4](噁)嗪-1-酮.它们及其某些重要中间体的结构分别采用红外光谱、质谱、核磁共振氢谱、核磁共振碳谱以及高分辨率质谱进行了表征.

  8. Photonic Bandgap (PBG) Shielding Technology

    Science.gov (United States)

    Bastin, Gary L.

    2007-01-01

    Photonic Bandgap (PBG) shielding technology is a new approach to designing electromagnetic shielding materials for mitigating Electromagnetic Interference (EM!) with small, light-weight shielding materials. It focuses on ground planes of printed wiring boards (PWBs), rather than on components. Modem PSG materials also are emerging based on planar materials, in place of earlier, bulkier, 3-dimensional PBG structures. Planar PBG designs especially show great promise in mitigating and suppressing EMI and crosstalk for aerospace designs, such as needed for NASA's Constellation Program, for returning humans to the moon and for use by our first human visitors traveling to and from Mars. Photonic Bandgap (PBG) materials are also known as artificial dielectrics, meta-materials, and photonic crystals. General PBG materials are fundamentally periodic slow-wave structures in I, 2, or 3 dimensions. By adjusting the choice of structure periodicities in terms of size and recurring structure spacings, multiple scatterings of surface waves can be created that act as a forbidden energy gap (i.e., a range of frequencies) over which nominally-conductive metallic conductors cease to be a conductor and become dielectrics. Equivalently, PBG materials can be regarded as giving rise to forbidden energy gaps in metals without chemical doping, analogous to electron bandgap properties that previously gave rise to the modem semiconductor industry 60 years ago. Electromagnetic waves cannot propagate over bandgap regions that are created with PBG materials, that is, over frequencies for which a bandgap is artificially created through introducing periodic defects

  9. Optimization Design of a 5kW Lift Type Vertical Axis Wind Turbine With Wind Shield-Growth Patterns%5kW遮蔽-增速升力型垂直轴风力机优化设计

    Institute of Scientific and Technical Information of China (English)

    姬俊峰; 邓召义; 蒋磊; 黄典贵

    2012-01-01

    本文详细介绍了5 kW遮蔽-增速垂直轴风力机的结构特点及主要参数。利用正交优化设计方法,采用计算流体力学软件,针对5 kW风力机,在叶片个数和遮蔽板安装位置半径一定的情况下,对翼型弦长、叶片转动扫掠面的半径、风轮旋转速度、遮蔽-增速板个数、遮蔽-增速板与叶片间的气动间隙以及遮蔽-增速板的安装角六个参数进行优化计算,找出一组最佳设计参数,进而设计出5 kW遮蔽-增速升力型垂直轴风力机,并对设计出的有遮蔽板与无遮蔽板两类型风力机的变工况特性进行比较分析。%This paper is devoted to a detailed study of the characteristics of the structure and most important aerodynamic design parameters of a 5 kW lift type vertical axis wind turbine with wind shield-growth patterns.As the number of turbine blades and the installation location of wind shield-growth patterns have been previously set,the computational fluid dynamics code was adopted in this study to obtain the numerical results and then six parameters,including blade airfoil chord length,radius of turbine rotor,rotational speed of the wind turbine,number of wind shield-growth patterns,clearance between the turbine blades and surrounding wind shield-growth patterns and installation angle of wind shield-growth patterns,were all optimized by using an orthogonal optimization algorithm.Based on the optimized parameters obtained,a 5 kW lift type vertical axis wind turbine can be designed.In addition,the performance characteristics of the designed wind turbine with and without wind shield-growth patterns were analyzed and compared under variable wind conditions.

  10. Radiation shielding device

    International Nuclear Information System (INIS)

    Purpose: To lower the shielding cost by providing a shielding wall having cavities and charging spherical shiedling materials in the cavities only when the shielding is required. Constitution: The structure comprises two parallel steel side plates aparting from each other to form a space therebetween and reinforcements such as H-type steels vertically provided between the side plates. The upper and the lower ends of the reinforcements are aparted from the upper and the lower edges of the side plates by a predetermined distance to form lateral passage between the top plate and the bottom plate. A guide plate having a plurality of openings is mounted on the upper ends of the reinforcements. If it is required for the structure to serve as the shield, spherical radioactive shielding materials are supplied through an injection port onto the guide plate while opening the injection port is opened and closing discharge port. The spherical radioactive shielding materials are fallen through the openings and filled in the space to thereby providing the structure with shielding performance. (Yoshino, Y.)

  11. Facility target insert shielding assessment

    Energy Technology Data Exchange (ETDEWEB)

    Mocko, Michal [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-06

    Main objective of this report is to assess the basic shielding requirements for the vertical target insert and retrieval port. We used the baseline design for the vertical target insert in our calculations. The insert sits in the 12”-diameter cylindrical shaft extending from the service alley in the top floor of the facility all the way down to the target location. The target retrieval mechanism is a long rod with the target assembly attached and running the entire length of the vertical shaft. The insert also houses the helium cooling supply and return lines each with 2” diameter. In the present study we focused on calculating the neutron and photon dose rate fields on top of the target insert/retrieval mechanism in the service alley. Additionally, we studied a few prototypical configurations of the shielding layers in the vertical insert as well as on the top.

  12. Shielding against galactic cosmic rays

    Science.gov (United States)

    Schimmerling, W.; Wilson, J. W.; Nealy, J. E.; Thibeault, S. A.; Cucinotta, F. A.; Shinn, J. L.; Kim, M.; Kiefer, R.

    1996-01-01

    Ions of galactic origin are modified but not attenuated by the presence of shielding materials. Indeed, the number of particles and the absorbed energy behind most shield materials increases as a function of shield thickness. The modification of the galactic cosmic ray composition upon interaction with shielding is the only effective means of providing astronaut protection. This modification is intimately conntected with the shield transport porperties and is a strong function of shield composition. The systematic behavior of the shield properites in terms of microscopic energy absorption events will be discussed. The shield effectiveness is examined with respect to convectional protection practice and in terms of a biological endpoint: the efficiency for reduction of the probability of transformation of shielded C3H1OT1/2 mouse cells. The relative advantage of developing new shielding technologies is discussed in terms of a shield performance as related to biological effect and the resulting uncertainty in estimating astronaut risk.

  13. Shielding member for thermonuclear device

    International Nuclear Information System (INIS)

    In a thermonuclear device for shielding fast neutrons by shielding members disposed in a shielding vessel (vacuum vessel and structures such as a blanket disposed in the vacuum vessel), the shielding member comprises a large number of shielding wires formed fine and short so as to have elasticity. The shielding wires are sealed in a shielding vessel together with water, and when the width of the shielding vessel is changed, the shielding wires follow after the change of the width while elastically deforming in the shielding vessel, so that great stress and deformation are not formed thereby enabling to improve reliability. In addition, the length, the diameter and the shape of each of the shielding wires can be selected in accordance with the shielding space of the shielding vessel. Even if the shape of the shielding vessel is complicated, the shielding wires can be inserted easily. Accordingly, the filling rate of the shielding members can be changed easily. It can be produced more easily compared with a conventional spherical pebbles. It can be produced more easily than existent spherical shielding pebbles thereby enabling to reduce the production cost. (N.H.)

  14. 7 CFR 1c.114 - Cooperative research.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Cooperative research. 1c.114 Section 1c.114 Agriculture Office of the Secretary of Agriculture PROTECTION OF HUMAN SUBJECTS § 1c.114 Cooperative research. Cooperative research projects are those projects covered by this policy which involve more than...

  15. iSHIELD - A Line Source Application of SHIELD11

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, W.R.; Rokni, S.H.; /SLAC

    2006-04-27

    iSHIELD11 performs a line-source numerical integration of radiation source terms that are defined by the iSHIELD11 computer code[1] . An example is provided to demonstrate how one can use iSHIELD11 to perform a shielding analysis for a 250 GeV electron linear accelerator.

  16. 成都富水砂卵石地层盾构刀盘设计及应用%Design and Application of Cutterhead of Shield Boring in Water-rich Sandy Gravel Strata in Chengdu

    Institute of Scientific and Technical Information of China (English)

    张家年; 胡玉娟

    2014-01-01

    Problems,including serious cutterhead wearing,cutterhead clogging and ground surface settlement,occur during the EPB shield boring in water-rich sandy gravel strata in Chengdu.As a result,the design of the cutterhead is optimized in terms of cutterhead structure,cutter arrangement,anti-wearing protection and ground conditioning.The shield with the optimized cutterhead achieves long-distance boring and good ground surface settlement control effect.The paper can provide reference for the design of the cutterheads of shields boring in similar strata in the future.%针对成都富水砂卵石地层盾构施工过程中刀盘刀具磨损严重、结泥饼和地表沉降大等问题,从盾构刀盘结构设计、刀具配置、耐磨保护及刀盘碴土改良等方面入手,对刀盘进行了针对性地改良设计。改良后的盾构刀盘不仅实现了长距离掘进,而且也有效地控制了地表沉降,对类似地层盾构刀盘设计具有一定的指导和借鉴作用。

  17. Characterization of Magnetic Field Immersed Photomultipliers from Double Chooz Experiment. Design and Construction of their Magnetic Shields; Caracterizacion de los fotomultiplicadores del experimento Double Chooz bajo campo magnetico y diseno y construccion de sus blindajes magneticos

    Energy Technology Data Exchange (ETDEWEB)

    Valdivia Valero, F. J.

    2007-12-28

    Flavour oscillations of neutrinos are a quantum-mechanical effect widely demonstrated. It is explained through interferences of their mass eigenstates, therefore, belonging to the physical area beyond the Standard Model. This work deals with the CIEMAT collaboration in the neutrino experiment Double Chooz. Such an experiment aims to measure the mixture angle {theta}{sub 1}3, one of the PMNS leptonic mixture matrix, with a un reached-before sensibility by decrease of systematic errors. For this, two identical scintillator detectors, equipped with PMT's, will be sited at different distances from two reactors located in the nuclear power plant CHOOZ B (France). The electronic neutrino flux from these reactors will be compared, explaining its deficit by flavour oscillations of these particles. The identity of both detectors will be diminished by the magnetic field effects on the PMT's response. Therefore, this study serves as for quantifying such an effects as for fitting the magnetic shields design that minimize them. Shielding measurements and final design of magnetic shields as much as the effect these ones cause in the PMT's response immersed in a monitored magnetic field are presented. (Author) 85 refs.

  18. Passive Magnetic Shielding in Gradient Fields

    CERN Document Server

    Bidinosti, C P

    2013-01-01

    The effect of passive magnetic shielding on dc magnetic field gradients imposed by both external and internal sources is studied. It is found that for concentric cylindrical or spherical shells of high permeability material, higher order multipoles in the magnetic field are shielded progressively better, by a factor related to the order of the multipole. In regard to the design of internal coil systems for the generation of uniform internal fields, we show how one can take advantage of the coupling of the coils to the innermost magnetic shield to further optimize the uniformity of the field. These results demonstrate quantitatively a phenomenon that was previously well-known qualitatively: that the resultant magnetic field within a passively magnetically shielded region can be much more uniform than the applied magnetic field itself. Furthermore we provide formulae relevant to active magnetic compensation systems which attempt to stabilize the interior fields by sensing and cancelling the exterior fields clos...

  19. TPX remote maintenance and shielding

    International Nuclear Information System (INIS)

    The Tokamak Physics Experiment machine design incorporates comprehensive planning for efficient and safe component maintenance. Three programmatic decisions have been made to insure the successful implementation of this objective. First, the tokamak incorporates radiation shielding to reduce activation of components and limit the dose rate to personnel working on the outside of the machine. This allows most of the ex-vessel equipment to be maintained through conventional ''hands-on'' procedures. Second, to the maximum extent possible, low activation materials will be used inside the shielding volume. This resulted in the selection of Titanium (Ti-6Al-4V) for the vacuum vessel and PFC structures. The third decision stipulated that the primary in-vessel components will be replaced or repaired via remote maintenance tools specifically provided for the task. The component designers have been given the responsibility of incorporating maintenance design and for proving the maintainability of the design concepts in full-scale mockup tests prior to the initiation of final fabrication. Remote maintenance of the TPX machine is facilitated by general purpose tools provided by a special purpose design team. Major tools will include an in-vessel transporter, a vessel transfer system and a large component transfer container. In addition, tools such as manipulators and remotely operable impact wrenches will be made available to the component designers by this group. Maintenance systems will also provide the necessary controls for this equipment

  20. TPX remote maintenance and shielding

    International Nuclear Information System (INIS)

    The Tokamak Physics Experiment (TPX) machine design incorporates comprehensive planning for efficient and safe component maintenance. Three programmatic decisions have been made to insure the successful implementation of this objective. First, the tokamak incorporates radiation shielding to reduce activation of components and limit the dose rate to personnel working on the outside of the machine. This allows most of the ex-vessel equipment to be maintained through conventional open-quotes hands-onclose quotes procedures. Second, to the maximum extent possible, low activation materials will be used inside the shielding volume. This resulted in the selection of Titanium (Ti-6Al-4V) for the vacuum vessel and Plasma Facing Components (PFC) structures. The third decision stipulated that the primary in-vessel components will be replaced or repaired via remote maintenance tools specifically provided for the task. The component designers have been given the responsibility of incorporating maintenance design and for proving the maintainability of the design concepts in full-scale mockup tests prior to the initiation of final fabrication. Remote maintenance of the TPX machine is facilitated by general purpose tools provided by a special purpose design team. Major tools will include an in-vessel transporter, a vessel transfer system and a large component transfer container. In addition, tools such as manipulators and remotely operable impact wrenches will be made available to the component designers by this group. Maintenance systems will also provide the necessary controls for this equipment

  1. 小型中子源高能中子照相装置准直屏蔽系统设计%Conception Design of Shielding Collimator System for High Energy Neutron Radiography with Minitype Neutron Source

    Institute of Scientific and Technical Information of China (English)

    吴洋; 窦海峰; 唐彬; 霍合勇

    2013-01-01

    Shielding collimator system is necessary in the neutron radiography installation; this issue gives the conception design of shielding collimator system for FNR about high energy neutron source by MCNP.Preliminarily ascertain the material component and dimension,confirm the neutron flux at imaging position,imaging distance,imaging field range of the FNP installation in theory.%准直屏蔽系统是中子照相装置的必要设备.本文采用蒙特卡洛中子输运程序(MCNP)等软件对高能中子准直屏蔽系统进行理论设计,初步确定了其材料构成和外观尺寸,从理论上确定了装置包括成像处注量率、成像距离及相应视场等关键参数.

  2. Space Shielding Materials for Prometheus Application

    Energy Technology Data Exchange (ETDEWEB)

    R. Lewis

    2006-01-20

    At the time of Prometheus program restructuring, shield material and design screening efforts had progressed to the point where a down-selection from approximately eighty-eight materials to a set of five ''primary'' materials was in process. The primary materials were beryllium (Be), boron carbide (B{sub 4}C), tungsten (W), lithium hydride (LiH), and water (H{sub 2}O). The primary materials were judged to be sufficient to design a Prometheus shield--excluding structural and insulating materials, that had not been studied in detail. The foremost preconceptual shield concepts included: (1) a Be/B{sub 4}C/W/LiH shield; (2) a Be/B{sub 4}C/W shield; (3) and a Be/B{sub 4}C/H{sub 2}O shield. Since the shield design and materials studies were still preliminary, alternative materials (e.g., {sup nal}B or {sup 10}B metal) were still being screened, but at a low level of effort. Two competing low mass neutron shielding materials are included in the primary materials due to significant materials uncertainties in both. For LiH, irradiation-induced swelling was the key issue, whereas for H{sub 2}O, containment corrosion without active chemistry control was key, Although detailed design studies are required to accurately estimate the mass of shields based on either hydrogenous material, both are expected to be similar in mass, and lower mass than virtually any alternative. Unlike Be, W, and B{sub 4}C, which are not expected to have restrictive temperature limits, shield temperature limits and design accommodations are likely to be needed for either LiH or H{sub 2}O. The NRPCT focused efforts on understanding swelting of LiH, and observed, from approximately fifty prior irradiation tests, that either casting ar thorough out-gassing should reduce swelling. A potential contributor to LiH swelling appears to be LiOH contamination due to exposure to humid air, that can be eliminated by careful processing. To better understand LiH irradiation performance and

  3. Radiation shielding curtain

    International Nuclear Information System (INIS)

    A radiation shield is described in the form of a stranded curtain made up of bead-chains whose material and geometry are selected to produce a cross-sectional density that is the equivalent of 0.25 mm or more of lead and which curtain may be mounted on various radiological devices to shield against scattered radiation while offering a minimum of obstruction to the radiologist

  4. 14-MeV neutron streaming through shield gaps

    International Nuclear Information System (INIS)

    Monte Carlo calculations have been performed to determine the neutron streaming through straight and single-bend gaps for three different shield thicknesses. A uniform plane source emitting 14-MeV neutrons with a cosine angular distribution was used in the analyses. The results obtained are discussed in terms of how they might be used in the early stages of a shield design to obtain approximate solutions to design questions. These results have direct implications regarding neutron-streaming problems that will be encountered in the shielding analyses of tokamak fusion reactors which are constructed from pie-shaped shield/vacuum chamber segments

  5. Steam generator hand hole shielding.

    Science.gov (United States)

    Cox, W E

    2000-05-01

    Seabrook Station is an 1198 MWE Pressurized Water Reactor (PWR) that began commercial operation in 1990. Expensive and dose intensive Steam Generator Replacement Projects among PWR operators have led to an increase in steam generator preventative maintenance. Most of this preventative maintenance is performed through access ports in the shell of the steam generator just above the tube sheet known as secondary side hand holes. Secondary side work activities performed through the hand holes are typically performed without the shielding benefit of water in the secondary side of the steam generator. An increase in cleaning and inspection work scope has led to an increase in dose attributed to steam generator secondary side maintenance. This increased work scope and the station goal of maintaining personnel radiation dose ALARA led to the development of the shielding concept described in this article. This shield design saved an estimated 2.5 person-rem (25 person-Smv) the first time it was deployed and is expected to save an additional 50 person-rem (500 person-mSv) over the remaining life of the plant. PMID:10770158

  6. ATLAS Award for Shield Supplier

    CERN Multimedia

    2004-01-01

    ATLAS technical coordinator Dr. Marzio Nessi presents the ATLAS supplier award to Vojtech Novotny, Director General of Skoda Hute.On 3 November, the ATLAS experiment honoured one of its suppliers, Skoda Hute s.r.o., of Plzen, Czech Republic, for their work on the detector's forward shielding elements. These huge and very massive cylinders surround the beampipe at either end of the detector to block stray particles from interfering with the ATLAS's muon chambers. For the shields, Skoda Hute produced 10 cast iron pieces with a total weight of 780 tonnes at a cost of 1.4 million CHF. Although there are many iron foundries in the CERN member states, there are only a limited number that can produce castings of the necessary size: the large pieces range in weight from 59 to 89 tonnes and are up to 1.5 metres thick.The forward shielding was designed by the ATLAS Technical Coordination in close collaboration with the ATLAS groups from the Czech Technical University and Charles University in Prague. The Czech groups a...

  7. Shielding Development for Nuclear Thermal Propulsion

    Science.gov (United States)

    Caffrey, Jarvis A.; Gomez, Carlos F.; Scharber, Luke L.

    2015-01-01

    Radiation shielding analysis and development for the Nuclear Cryogenic Propulsion Stage (NCPS) effort is currently in progress and preliminary results have enabled consideration for critical interfaces in the reactor and propulsion stage systems. Early analyses have highlighted a number of engineering constraints, challenges, and possible mitigating solutions. Performance constraints include permissible crew dose rates (shared with expected cosmic ray dose), radiation heating flux into cryogenic propellant, and material radiation damage in critical components. Design strategies in staging can serve to reduce radiation scatter and enhance the effectiveness of inherent shielding within the spacecraft while minimizing the required mass of shielding in the reactor system. Within the reactor system, shield design is further constrained by the need for active cooling with minimal radiation streaming through flow channels. Material selection and thermal design must maximize the reliability of the shield to survive the extreme environment through a long duration mission with multiple engine restarts. A discussion of these challenges and relevant design strategies are provided for the mitigation of radiation in nuclear thermal propulsion.

  8. Structural Monitoring of Metro Infrastructure during Shield Tunneling Construction

    Directory of Open Access Journals (Sweden)

    L. Ran

    2014-01-01

    Full Text Available Shield tunneling construction of metro infrastructure will continuously disturb the soils. The ground surface will be subjected to uplift or subsidence due to the deep excavation and the extrusion and consolidation of the soils. Implementation of the simultaneous monitoring with the shield tunnel construction will provide an effective reference in controlling the shield driving, while how to design and implement a safe, economic, and effective structural monitoring system for metro infrastructure is of great importance and necessity. This paper presents the general architecture of the shield construction of metro tunnels as well as the procedure of the artificial ground freezing construction of the metro-tunnel cross-passages. The design principles for metro infrastructure monitoring of the shield tunnel intervals in the Hangzhou Metro Line 1 are introduced. The detailed monitoring items and the specified alarming indices for construction monitoring of the shield tunneling are addressed, and the measured settlement variations at different monitoring locations are also presented.

  9. Led Astray by Hemoglobin A1c

    Directory of Open Access Journals (Sweden)

    Jean Chen MD

    2016-01-01

    Full Text Available Hemoglobin A1c (A1c is used frequently to diagnose and treat diabetes mellitus. Therefore, it is important be aware of factors that may interfere with the accuracy of A1c measurements. This is a case of a rare hemoglobin variant that falsely elevated a nondiabetic patient’s A1c level and led to a misdiagnosis of diabetes. A 67-year-old male presented to endocrine clinic for further management after he was diagnosed with diabetes based on an elevated A1c of 10.7%, which is approximately equivalent to an average blood glucose of 260 mg/dL. Multiple repeat A1c levels remained >10%, but his home fasting and random glucose monitoring ranged from 92 to 130 mg/dL. Hemoglobin electrophoresis and subsequent genetic analysis diagnosed the patient with hemoglobin Wayne, a rare hemoglobin variant. This variant falsely elevates A1c levels when A1c is measured using cation-exchange high-performance liquid chromatography. When the boronate affinity method was applied instead, the patient’s A1c level was actually 4.7%. Though hemoglobin Wayne is clinically silent, this patient was erroneously diagnosed with diabetes and started on an antiglycemic medication. Due to this misdiagnosis, the patient was at risk of escalation in his “diabetes management” and hypoglycemia. Therefore, it is important that providers are aware of factors that may result in hemoglobin A1c inaccuracy including hemoglobin variants.

  10. Inner Shielding of the COMET Cosmic Veto System

    OpenAIRE

    Markin, Oleg

    2015-01-01

    A simulation of neutrons traversing a shield beneath the COMET scintillator strip cosmic-veto counter is accomplished using the Geant4 toolkit. A Geant4 application is written with an appropriate detector construction and a possible spectrum of neutron's energy. The response of scintillator strips to neutrons is studied in detail. A design of the shield is optimized to ensure the time loss concerned with fake veto signals caused by neutrons from muon captures is tolerable. Materials of shield...

  11. A study on the shielding mechanisms of SOI pixel detector

    OpenAIRE

    Lu, Yunpeng; Liu, Yi; Wu, Zhigang; Ouyang, Qun; Arai, Yasuo

    2015-01-01

    In order to tackle the charge injection issue that had perplexed the counting type SOI pixel for years, two successive chips CPIXTEG3 and CPIXTEG3b were developed utilizing two shielding mechanisms, Nested-well and Double-SOI, in the LAPIS process. A TCAD simulation showed the shielding effectiveness influenced by the high sheet resistance of shielding layers. Test structures specially designed to measure the crosstalk associated to charge injection were implemented in CPIXTEG3/3b. Measuremen...

  12. Shielding Effectiveness of Composites Containing Flaky Inclusions

    Institute of Scientific and Technical Information of China (English)

    WANG Qingguo; QU Zhaoming; WANG Yilong

    2013-01-01

    To investigate the quantitative relationship between the electromagnetic-shielding property of composites and the distribution of inclusions,a scheme for predicting the shielding effectiveness of composites containing variously-distributed flaky inclusions is proposed.The scheme is based on equivalent parameters of homogeneous comparison materials and the plane-wave shielding theory.It leads to explicit formulas for the shielding effectiveness of multi-layered composites in terms of microstructural parameters that characterize the shape,distribution and orientation of the inclusions.For single layer composite that contains random and aligned flaky silver-coated carbonyl-iron particles with fractions of different volume,the predicted shielding effectiveness agrees well with the experimental data.As for composites containing aligned flaky particles,the shielding effectiveness obtained by the proposed scheme and experiment data is higher than that the random case,e.g.about 20 dB higher at 750 MHz.The proposed scheme is a straightforward method for optimizing future composite designs.

  13. Neutron shielding material

    International Nuclear Information System (INIS)

    From among the neutron shielding materials of the 'kobesh' series developed by Kobe Steel, Ltd. for transport and storage packagings, silicon rubber base type material has been tested for several items with a view to practical application and official authorization, and in order to determine its adaptability to actual vessels. Silicon rubber base type 'kobesh SR-T01' is a material in which, from among the silicone rubber based neutron shielding materials, the hydrogen content is highest and the boron content is most optimized. Its neutron shielding capability has been already described in the previous report (Taniuchi, 1986). The following tests were carried out to determine suitability for practical application; 1) Long-term thermal stability test 2) Pouring test on an actual-scale model 3) Fire test The experimental results showed that the silicone rubber based neutron shielding material has good neutron shielding capability and high long-term fire resistance, and that it can be applied to the advanced transport packaging. (author)

  14. Using the shield for thermal energy storage in pulsar

    Energy Technology Data Exchange (ETDEWEB)

    Sager, G.T. [General Atomics, San Diego, CA (United States); Sze, D.K. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Wong, C.P.C. [General Atomics, San Diego, CA (United States); Bathke, C.G. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Blanchard, J.P. [University of Wisconsin at Madison, Madison, WI 53706 (United States); Brimer, C. [McDonnell Douglas Aerospace, PO Box 516, Mail Code 3064204, St. Louis, MO 63166-0516 (United States); Cheng, E.T. [TSI Research Inc., 225 Stevens Avenue, Suite 203, Solana Beach, CA 92075 (United States); El-Guebaly, L.A. [University of Wisconsin at Madison, Madison, WI 53706 (United States); Hasan, M.Z. [University of California at Los Angeles, Los Angeles, CA 90024 (United States); Najmabadi, F. [University of California at San Diego, San Diego, CA 92037 (United States); Sharafat, S. [University of California at Los Angeles, Los Angeles, CA 90024 (United States); Sviatoslavski, I.N. [University of Wisconsin at Madison, Madison, WI 53706 (United States); Waganer, L. [McDonnell Douglas Aerospace, PO Box 516, Mail Code 3064204, St. Louis, MO 63166-0516 (United States)

    1995-03-01

    The PULSAR pulsed tokamak power plant design utilizes the outboard shield for thermal energy storage to maintain full 1000MW(e) output during the dwell period of 200s. Thermal energy resulting from direct nuclear heating is accumulated in the shield during the 7200s fusion power production phase. The maximum shield temperature may be much higher than that for the blanket because radiation damage is significantly reduced. During the dwell period, thermal power discharged from the shield and coolant temperature are simultaneously regulated by controlling the coolant mass flow rate at the shield inlet. This is facilitated by throttled coolant bypass. Design concepts using helium and lithium coolant have been developed. Two-dimensional time-dependent thermal hydraulic calculations were performed to confirm performance capabilities required of the design concepts. The results indicate that the system design and performance can accommodate uncertainties in material limits or the length of the dwell period. (orig.).

  15. Manufacture of blanket shield modules for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Lorenzetto, P. [EFDA CSU Garching, Boltzmannstr. 2, D-85748 Garching (Germany)]. E-mail: Patrick.Lorenzetto@tech.efda.org; Boireau, B. [AREVA Centre Technique de Framatome, BP181, F-71200 Le Creusot (France); Boudot, C. [AREVA Centre Technique de Framatome, BP181, F-71200 Le Creusot (France); Bucci, P. [CEA, DTEN/S3ME/LMIC, 17 rue des Martyrs, F-38054 Grenoble (France); Furmanek, A. [EFDA CSU Garching, Boltzmannstr. 2, D-85748 Garching (Germany); Ioki, K. [ITER IT, Boltzmannstr. 2, D-85748 Garching (Germany); Liimatainen, J. [Metso Powdermet, P.O. Box 306, FIN-33101 Tampere (Finland); Peacock, A. [EFDA CSU Garching, Boltzmannstr. 2, D-85748 Garching (Germany); Sherlock, P. [NNC Ltd., Booths Hall, Knutsford, Cheshire WA16 8QZ (United Kingdom); Taehtinen, S. [VTT Industrial Systems, P.O. Box 1704, Espoo, FIN-02044 VTT (Finland)

    2005-11-15

    A research and development programme for the ITER blanket shield modules has been implemented in Europe to provide input for the design and the manufacture of the full-scale production components. It involves in particular the fabrication and testing of mock-ups (small scale and medium scale) and full-scale prototypes of shield blocks (SB) and first wall (FW) panels. The manufacturing feasibility of FW panels has been demonstrated for two copper alloy candidates. Two designs have been developed for the manufacture of the SB, one for a conventional fabrication route and one for a fabrication route based on the hot isostatic press technology. This paper presents the fabrication routes developed in Europe for the manufacture of the ITER Shield modules.

  16. The Role of Metformin Response in Lipid Metabolism in Patients with Recent-Onset Type 2 Diabetes: HbA1c Level as a Criterion for Designating Patients as Responders or Nonresponders to Metformin.

    Directory of Open Access Journals (Sweden)

    Zahra Kashi

    Full Text Available In this study, we investigated whether response to metformin, the most frequently drug for diabetes treatment, influences the therapeutic effects of antilipidemic medication in newly diagnosed patients with type 2 diabetes mellitus (T2DM.A total of 150 patients with T2DM were classified into two groups following 3 months of metformin therapy (1000 mg twice daily: responders (patients showing ≥1% reduction in HbA1c from baseline and nonresponders (patients showing <1% reduction in HbA1c from baseline. The patients received atorvastatin 20 mg, gemfibrozil 300 mg, or atorvastatin 20 mg and gemfibrozil 300 mg daily.HbA1c and fasting glucose levels were significantly different between baseline and 3 months among responders receiving atorvastatin; however, these differences were not statistically significant in nonresponders. Atherogenic ratios of low-density lipoprotein cholesterol to high-density lipoprotein cholesterol (LDL-C/HDL-C; p = 0.002, total cholesterol to HDL-C (TC/HDL-C; p<0.001 and AIP (the atherogenic index of plasma; p = 0.004 decreased significantly in responders receiving atorvastatin than in nonresponders. Moreover, responders receiving atorvastatin showed a significant increase in HDL-C levels but nonresponders receiving atorvastatin did not (p = 0.007. The multivariate model identified a significant association between metformin response (as the independent variable and TG, TC, HDL-C and LDL-C (dependent variables; Wilk's λ = 0.927, p = 0.036.Metformin response affects therapeutic outcomes of atorvastatin on atherogenic lipid markers in patients newly diagnosed with T2DM. Metformin has a greater impact on BMI in responders of metformin compared to nonresponders. Adoption of better therapeutic strategies for reducing atherogenic lipid markers may be necessary for metformin nonresponders.

  17. Radiation shielding of 131I therapeutic ward in department

    International Nuclear Information System (INIS)

    Objective: To rebuild an 131I therapeutic ward of the department of nuclear medicine in the hospital, and design the radiation shielding to make the radiation safety achieve the national standards. Methods: According to the protection demands of national relating standards, the design of the ward was based on the basic principles and methods of radiation shielding of 131I, and combined the distribution of radioactive sources, rooms and people. Results: The design parameters and radioprotection data of the rebuilt ward were obtained and the radiation shielding was safe by monitoring. Conclusion: The design of the 131I therapeutic ward achieved the anticipated target that the radiation safety could be controlled. (authors)

  18. GIS盆式绝缘子金属外圈及屏蔽内环设计的必要性%Necessity of Design for the Metal Outer Rings and Shielding Inner Ring of GIS Basin-type Insulator

    Institute of Scientific and Technical Information of China (English)

    黎斌

    2012-01-01

    The GIS basin-type insulator is a very important solid insulating part in GIS. In this paper,the theoretical analysis and practical experience summary for the necessity of metal outer ring and shielding inner ring have been carried out; this is very important to further improve the GIS operational reliability and reduce the cost of GIS design. Author has conducted GIS electric field distribution, partial discharge of UHF electromagnetic wave radiation, and measurement, as well as strength and electrical property of disc insulators, 3 aspects analysis; the questions about design for basin-type insulator with metal outer ring and shielding inner ring are raised, and the design requirements of GIS disc insulator reasonable structure are presented.%笔者以GIS电场分布、局部放电超高频电磁波的辐射及测量以及盆式绝缘子强度与电性能等3方面分析,对盆式绝缘子带金属外圈和屏蔽内环的设计提出质疑,并提出了GIS盆式绝缘子合理的结构设计要求.

  19. Radiation shielding materials

    International Nuclear Information System (INIS)

    Purpose: To obtain putty-like shielding materials excellent in the radiation shielding and packing workability for use in penetrations of electrical wires or pipeways in a nuclear installation. Constitution: A putty-like material is prepared from 100 parts by weight of a binder comprising a grease or the like having viscosity of greater than 5000 cst or an immiscible consistency of greater than 100 (JIS K 2220 (1980) para. 5.3.4) at 25 0C and from 1200 to 4000 parts by weight of high density inorganic powder such as lead powder or lead oxide powder having a density of greater than 5 g/cm3 and such a particle size that more than 95 % thereof passes through a 145 mesh sieve. The putty-like material is adjusted such that it has 1 - 35 mm of softness (JIS A 5752) at normal temperature, more than 1 g/5 sec of injection amount and a density of greater than 4 g/cm3. In this way, non-curable radiation shielding agent with excellent X-ray or γ-ray shielding property and being capable of packed densely to void portions can be obtained. (Ikeda, J.)

  20. Adjoint Variable Method for the Study of Combined Active and Passive Magnetic Shielding

    Directory of Open Access Journals (Sweden)

    Peter Sergeant

    2008-01-01

    Full Text Available For shielding applications that cannot sufficiently be shielded by only a passive shield, it is useful to combine a passive and an active shield. Indeed, the latter does the “finetuning” of the field reduction that is mainly caused by the passive shield. The design requires the optimization of the geometry of the passive shield, the position of all coils of the active shield, and the real and imaginary components of the currents (when working in the frequency domain. As there are many variables, the computational effort for the optimization becomes huge. An optimization using genetic algorithms is compared with a classical gradient optimization and with a design sensitivity approach that uses an adjoint system. Several types of active and/or passive shields with constraints are designed. For each type, the optimization was carried out by all three techniques in order to compare them concerning CPU time and accuracy.

  1. Hinged Shields for Machine Tools

    Science.gov (United States)

    Lallande, J. B.; Poland, W. W.; Tull, S.

    1985-01-01

    Flaps guard against flying chips, but fold away for tool setup. Clear plastic shield in position to intercept flying chips from machine tool and retracted to give operator access to workpiece. Machine shops readily make such shields for own use.

  2. Methods for calculating radiation attenuation in shields

    International Nuclear Information System (INIS)

    In recent years the development of high-speed digital computers of large capacity has revolutionized the field of reactor shield design. For compact special-purpose reactor shields, Monte-Carlo codes in two- and three dimensional geometries are now available for the proper treatment of both the neutron and gamma- ray problems. Furthermore, techniques are being developed for the theoretical optimization of minimum-weight shield configurations for this type of reactor system. In the design of land-based power reactors, on the other hand, there is a strong incentive to reduce the capital cost of the plant, and economic considerations are also relevant to reactors designed for merchant ship propulsion. In this context simple methods are needed which are economic in their data input and computing time requirements and which, at the same time, are sufficiently accurate for design work. In general the computing time required for Monte-Carlo calculations in complex geometry is excessive for routine design calculations and the capacity of the present codes is inadequate for the proper treatment of large reactor shield systems in three dimensions. In these circumstances a wide range of simpler techniques are currently being employed for design calculations. The methods of calculation for neutrons in reactor shields fall naturally into four categories: Multigroup diffusion theory; Multigroup diffusion with removal sources; Transport codes; and Monte Carlo methods. In spite of the numerous Monte- Carlo techniques which are available for penetration and back scattering, serious problems are still encountered in practice with the scattering of gamma rays from walls of buildings which contain critical facilities and also concrete-lined discharge shafts containing irradiated fuel elements. The considerable volume of data in the unclassified literature on the solution of problems of this type in civil defence work appears not to have been evaluated for reactor shield design. In

  3. Scale-PC shielding analysis sequences

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, S.M.

    1996-05-01

    The SCALE computational system is a modular code system for analyses of nuclear fuel facility and package designs. With the release of SCALE-PC Version 4.3, the radiation shielding analysis community now has the capability to execute the SCALE shielding analysis sequences contained in the control modules SAS1, SAS2, SAS3, and SAS4 on a MS- DOS personal computer (PC). In addition, SCALE-PC includes two new sequences, QADS and ORIGEN-ARP. The capabilities of each sequence are presented, along with example applications.

  4. Shielding during x-ray examination of pediatric female patients with developmental dysplasia of the hip

    International Nuclear Information System (INIS)

    Patients with developmental dysplasia of the hip (DDH) generally undergo multiple x-ray examinations of both hip joints. During these examinations, the gonads are completely exposed to radiation, unless shielded. Although many types and sizes of gonad shields exist, they often do not provide adequate protection because of size and placement issues; additionally, these shields are frequently omitted for female patients. Our aim was to assess gonad protection during x-ray examination that is provided by gonad shields designed for individual female patients with DDH. We retrospectively retrieved data from the Picture Archiving and Communication System database; pelvic plain x-ray films from 766 females, 18 years old or younger, were included in our analysis. Based on x-ray measurements of the anterior superior iliac spine, we developed a system of gonad shield design that depended on the distance between anterior superior iliac spine markers. We custom-made shields and then examined shielding rates and shielding accuracy before and after these new shields became available. Standard (general-purpose) shields were used before our custom design project was implemented. The shielding rate and shielding accuracy were, respectively, 14.5% and 8.4% before the project was implemented and 72.7% and 32.2% after it was implemented. A shield that is more anatomically correct and available in several different sizes may increase the likelihood of gonad protection during pelvic x-ray examinations. (paper)

  5. A1C Test and Diabetes

    Science.gov (United States)

    ... of Diabetes Educators American Diabetes Association JDRF MedlinePlus Diabetes Disease Organizations ​There are many organizations who provide ... KB). Alternate Language URL The A1C Test and Diabetes Page Content On this page: What is the ...

  6. Calculation system analysis for radiation shielding

    International Nuclear Information System (INIS)

    This work consists of the computational system implementation for nuclear reactor shielding analysis. The system has as objectives to facilitate the installation of the calculation framework, problem set-up, and results analysis. Several computational programmes commonly used for cross-section preparation and radiation transport were chosen for the system. This work represents the capacity necessary for nuclear reactor and particle accelerator shielding design, to aid in nuclear experiments and in the utilization of nuclear techniques that require the radiation field calculation. The system was implemented in PC-DOS environment and consists of the necessary and sufficient programs and data for generation of the cross sections, groups constants, self-shielding factors, activation sources, for the calculation of neutron and gamma-ray fluence, dose rates, and other types of response functions. (author). 11 refs., 8 figs

  7. Radiation shielding effectiveness of newly developed superconductors

    Science.gov (United States)

    Singh, Vishwanath P.; Medhat, M. E.; Badiger, N. M.; Saliqur Rahman, Abu Zayed Mohammad

    2015-01-01

    Gamma ray shielding effectiveness of superconductors with a high mass density has been investigated. We calculated the mass attenuation coefficients, the mean free path (mfp) and the exposure buildup factor (EBF). The gamma ray EBF was computed using the Geometric Progression (G-P) fitting method at energies 0.015-15 MeV, and for penetration depths up to 40 mfp. The fast-neutron shielding effectiveness has been characterized by the effective neutron removal cross-section of the superconductors. It is shown that CaPtSi3, CaIrSi3, and Bi2Sr2Ca1Cu2O8.2 are superior shielding materials for gamma rays and Tl0.6Rb0.4Fe1.67Se2 for fast neutrons. The present work should be useful in various applications of superconductors in fusion engineering and design.

  8. The heterogeneous anti-radiation shield for spacecraft*

    Science.gov (United States)

    Telegin, S. V.; Draganyuk, O. N.

    2016-04-01

    The paper deals with modeling of elemental composition and properties of heterogeneous layers in multilayered shields to protect spacecraft onboard equipment from radiation emitted by the natural Earth’s radiation belt. This radiation causes malfunctioning of semiconductor elements in electronic equipment and may result in a failure of the spacecraft as a whole. We consider four different shield designs and compare them to the most conventional radiation-protective material for spacecraft - aluminum. Out of light and heavy chemical elements we chose the materials with high reaction cross sections and low density. The mass attenuation coefficient of boron- containing compounds is 20% higher than that of aluminum. Heterogeneous shields consist of three layers: a glass cloth, borated material, and nickel. With a protective shield containing heavy metal the output bremsstrahlung can be reduced. The amount of gamma rays that succeed to penetrate the shield is 4 times less compared to aluminum. The shields under study have the thicknesses of 5.95 and 6.2 mm. A comparative analysis of homogeneous and multilayered protective coatings of the same chemical composition has been performed. A heterogeneous protective shield has been found to be advantageous in weight and shielding properties over its homogeneous counterparts and aluminum. The dose characteristics and transmittance were calculated by the Monte Carlo method. The results of our study lead us to conclude that a three-layer boron carbide shield provides the most effective protection from radiation. This shield ensures twice as low absorbed dose and 4 times less the number of penetrated gamma-ray photons compared to its aluminum analogue. Moreover, a heterogeneous shield will have a weight 10% lighter than aluminum, with the same attenuation coefficient of the electron flux. Such heterogeneous shields can be used to protect spacecraft launched to geostationary orbit. Furthermore, a protective boron-containing and

  9. Secondary gamma-ray data for shielding calculation

    International Nuclear Information System (INIS)

    In deep penetration transport calculations, the integral design parameters is determined mainly by secondary particles which are produced by interactions of the primary radiation with materials. The shield thickness and the biological dose rate at a given point of a bulk shield are determined from the contribution from secondary gamma rays. The heat generation and the radiation damage in the structural and shield materials depend strongly on the secondary gamma rays. In this paper, the status of the secondary gamma ray data and its further problems are described from the viewpoint of shield design. The secondary gamma-ray data in ENDF/B-IV and POPOP4 are also discussed based on the test calculations made for several shield assemblies. (author)

  10. Capacitive Proximity Sensors With Additional Driven Shields

    Science.gov (United States)

    Mcconnell, Robert L.

    1993-01-01

    Improved capacitive proximity sensors constructed by incorporating one or more additional driven shield(s). Sensitivity and range of sensor altered by adjusting driving signal(s) applied to shield(s). Includes sensing electrode and driven isolating shield that correspond to sensing electrode and driven shield.

  11. A high-performance magnetic shield with large length-to-diameter ratio

    Science.gov (United States)

    Dickerson, Susannah; Hogan, Jason M.; Johnson, David M. S.; Kovachy, Tim; Sugarbaker, Alex; Chiow, Sheng-wey; Kasevich, Mark A.

    2012-06-01

    We have demonstrated a 100-fold improvement in the magnetic field uniformity on the axis of a large aspect ratio, cylindrical, mumetal magnetic shield by reducing discontinuities in the material of the shield through the welding and re-annealing of a segmented shield. The three-layer shield reduces Earth's magnetic field along an 8 m region to 420 μG (rms) in the axial direction, and 460 and 730 μG (rms) in the two transverse directions. Each cylindrical shield is a continuous welded tube which has been annealed after manufacture and degaussed in the apparatus. We present both experiments and finite element analysis that show the importance of uniform shield material for large aspect ratio shields, favoring a welded design over a segmented design. In addition, we present finite element results demonstrating the smoothing of spatial variations in the applied magnetic field by cylindrical magnetic shields. Such homogenization is a potentially useful feature for precision atom interferometric measurements.

  12. Combustor bulkhead heat shield assembly

    Energy Technology Data Exchange (ETDEWEB)

    Zeisser, M.H.

    1990-06-19

    This paper describes a gas turbine engine having an annular combustion chamber defined by an annular, inner liner, a concentric outer liner, and an upstream annular combustor head, wherein the head includes a radially extending bulkhead having circumferentially distributed openings for each receiving an individual fuel nozzle therethrough. It comprises: a segmented heat shield assembly, disposed between the combustion chamber interior and the bulkhead, including generally planar, sector shaped heat shields, each shield abutting circumferentially with two next adjacent shields and extending radially from proximate the inner liner to proximate the outer liner, the plurality of shields collectively defining an annular protective barrier, and wherein each sector shaped shield further includes an opening, corresponding to one of the bulkhead nozzle openings for likewise receiving the corresponding nozzle therethrough, the shield opening further including an annular lip extending toward the bulkhead and being received within the bulkhead opening, raised ridges on the shield backside, the ridges contacting the facing bulkhead surface and defining a flow path for a flow of cooling air issuing from a sized supply opening disposed in the bulkhead, the flow path running ultimately from adjacent the annular lip to the edges of each shield segment, wherein the raised edges extend fully along the lateral, circumferentially spaced edges of each shield segment and about the adjacent shield segments wherein the raised ridges further extend circumferentially between the annular lip and the abutting edge ridges.

  13. Grounding and shielding circuits and interference

    CERN Document Server

    Morrison, Ralph

    2016-01-01

    Applies basic field behavior in circuit design and demonstrates how it relates to grounding and shielding requirements and techniques in circuit design This book connects the fundamentals of electromagnetic theory to the problems of interference in all types of electronic design. The text covers power distribution in facilities, mixing of analog and digital circuitry, circuit board layout at high clock rates, and meeting radiation and susceptibility standards. The author examines the grounding and shielding requirements and techniques in circuit design and applies basic physics to circuit behavior. The sixth edition of this book has been updated with new material added throughout the chapters where appropriate. The presentation of the book has also been rearranged in order to reflect the current trends in the field.

  14. Postoperative Trunk Shift in Lenke 1C Scoliosis

    DEFF Research Database (Denmark)

    Wang, Yu; Bünger, Cody Eric; Wu, Chunsen;

    2012-01-01

    STUDY DESIGN: A risk factor analysis study. OBJECTIVE: To identify the causative factors for postoperative trunk shift in Lenke 1C scoliosis and investigate how to prevent it. SUMMARY OF BACKGROUND DATA: When selective thoracic fusion is performed, postoperative trunk shift is a significant problem...... in the management of Lenke 1C scoliosis. It is often accompanied by unsatisfactory clinical outcomes and a risk of reoperation. METHODS: We reviewed all the patients with adolescent idiopathic scoliosis (AIS) surgically treated in our institution from 2002 through 2008. Inclusion criteria were as follows: (1...... of MT: TL/L Cobb angle) - 3.9 (preoperative LIV-LEV difference). The model R2 = 0.55. CONCLUSION: Both LIV selection and ratio of MT: TL/L curve were found to be highly correlated with the onset of postoperative trunk shift in Lenke 1C scoliosis. Amount of correction obtained by surgery, however, did...

  15. Shielding calculations for the antiproton target area

    International Nuclear Information System (INIS)

    Shielding calculations performed in conjunction with the design of the Fermilab antiproton target hall are summarized. The following radiological considerations were examined: soil activation, residual activity of components, and beam-on radiation. In addition, at the request of the designers, the energy deposition in the proposed graphite beam dump was examined for several targeting conditions in order to qualitatively determine its ability to survive

  16. Magnetic shielding tests for MFTF-B neutral beamlines

    International Nuclear Information System (INIS)

    A test program to determine the effectiveness of various magnetic shielding designs for MFTF-B beamlines was established at Lawrence Livermore National Laboratory (LLNL). The proposed one-tenth-scale shielding-design models were tested in a uniform field produced by a Helmholtz coil pair. A similar technique was used for the MFTF source-injector assemblies, and the model test results were confirmed during the Technology Demonstration in 1982. The results of these tests on shielding designs for MFTF-B had an impact on the beamline design for MFTF-B. The iron-core magnet and finger assembly originally proposed were replaced by a simple, air-core, race-track-coil, bending magnet. Only the source injector needs to be magnetically shielded from the fields of approximately 400 gauss

  17. Passive magnetic shielding in static gradient fields

    Science.gov (United States)

    Bidinosti, C. P.; Martin, J. W.

    2014-04-01

    The effect of passive magnetic shielding on dc magnetic field gradients imposed by both external and internal sources is studied for two idealized shield models: concentric spherical and infinitely-long cylindrical shells of linear material. It is found that higher-order multipoles of an externally applied magnetic field are always shielded progressively better for either geometry by a factor related to the order of the multipole. In regard to the design of internal coil systems, we determine reaction factors for the general multipole field and provide examples of how one can take advantage of the coupling of the coils to the innermost shell to optimize the uniformity of the field. Furthermore, we provide formulae relevant to active magnetic compensation systems which attempt to stabilize the interior fields by sensing and cancelling the exterior fields close to the outermost shell. Overall this work provides a comprehensive framework that is useful for the analysis and optimization of dc magnetic shields, serving as a theoretical and conceptual design guide as well as a starting point and benchmark for finite-element analysis.

  18. A contribution to shielding effectiveness analysis of shielded tents

    Directory of Open Access Journals (Sweden)

    Vranić Zoran M.

    2004-01-01

    Full Text Available An analysis of shielding effectiveness (SE of the shielded tents made of the metallised fabrics is given. First, two electromagnetic characteristic fundamental for coupling through electrically thin shield, the skin depth break frequency and the surface resistance or transfer impedance, is defined and analyzed. Then, the transfer function and the SE are analyzed regarding to the frequency range of interest to the Electromagnetic Compatibility (EMC Community.

  19. Utilizing electromagnetic shielding textiles in wireless body area networks.

    Science.gov (United States)

    Sung, Grace H H; Aoyagi, Takahiro; Hernandez, Marco; Hamaguchi, Kiyoshi; Kohno, Ryuji

    2010-01-01

    For privacy and radio propagation controls, electromagnetic shielding textile could be adopted in WBANs. The effect of including a commercially available electromagnetic shielding apron in WBANs was examined in this paper. By having both the coordinator and the sensor covered by the shielding apron, signal could be confined around the body; however signal strength can be greatly influenced by body movements. Placing the shielding apron underneath both antennas, the transmission coefficient could be on average enhanced by at least 10dB, with less variation comparing to the case when apron does not exist. Shielding textiles could be utilized in designing a smart suit to enhance WBANs performance, and to prevent signals travelling beyond its intended area. PMID:21095666

  20. Measurement of the transient shielding effectiveness of shielding cabinets

    Directory of Open Access Journals (Sweden)

    H. Herlemann

    2008-05-01

    Full Text Available Recently, new definitions of shielding effectiveness (SE for high-frequency and transient electromagnetic fields were introduced by Klinkenbusch (2005. Analytical results were shown for closed as well as for non closed cylindrical shields. In the present work, the shielding performance of different shielding cabinets is investigated by means of numerical simulations and measurements inside a fully anechoic chamber and a GTEM-cell. For the GTEM-cell-measurements, a downscaled model of the shielding cabinet is used. For the simulations, the numerical tools CONCEPT II and COMSOL MULTIPHYSICS were available. The numerical results agree well with the measurements. They can be used to interpret the behaviour of the shielding effectiveness of enclosures as function of frequency. From the measurement of the electric and magnetic fields with and without the enclosure in place, the electric and magnetic shielding effectiveness as well as the transient shielding effectiveness of the enclosure are calculated. The transient SE of four different shielding cabinets is determined and discussed.

  1. A1C Test and Diabetes

    Science.gov (United States)

    ... Top ] Will the A1C test show changes in blood glucose levels? Large changes in a person’s blood glucose levels ... test that provides information about a person’s average levels of blood glucose, also called blood sugar, over the past 3 ...

  2. 7 CFR 1c.107 - IRB membership.

    Science.gov (United States)

    2010-01-01

    ... Office of the Secretary of Agriculture PROTECTION OF HUMAN SUBJECTS § 1c.107 IRB membership. (a) Each IRB... of race, gender, and cultural backgrounds and sensitivity to such issues as community attitudes, to promote respect for its advice and counsel in safeguarding the rights and welfare of human subjects....

  3. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua

    2004-09-16

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).

  4. Performance study of galactic cosmic ray shield materials

    Science.gov (United States)

    Kim, Myung-Hee Y.; Wilson, John W.; Thibeault, Sheila A.; Nealy, John E.; Badavi, Francis F.; Kiefer, Richard L.

    1994-11-01

    The space program is faced with two difficult radiation protection issues for future long-term operations. First, retrofit of shield material or conservatism in shield design is prohibitively expensive and often impossible. Second, shielding from the cosmic heavy ions is faced with limited knowledge on the physical properties and biological responses of these radiations. The current status of space shielding technology and its impact on radiation health is discussed herein in terms of conventional protection practice and a test biological response model. The impact of biological response on the selection of optimum materials for cosmic ray shielding is presented in terms of the transmission characteristics of the shield material. Although the systematics of nuclear cross sections are able to demonstrate the relation of exposure risk to shield-material composition, the current uncertainty in-nuclear cross sections will not allow an accurate evaluation of risk reduction. This paper presents a theoretical study of risk-related factors and a pilot experiment to study the effectiveness of choice of shield materials to reduce the risk in space operations.

  5. SHIELD verification and validation report

    Energy Technology Data Exchange (ETDEWEB)

    Boman, C.

    1992-02-01

    This document outlines the verification and validation effort for the SHIELD, SHLDED, GEDIT, GENPRT, FIPROD, FPCALC, and PROCES modules of the SHIELD system code. Along with its predecessors, SHIELD has been in use at the Savannah River Site (SRS) for more than ten years. During this time the code has been extensively tested and a variety of validation documents have been issued. The primary function of this report is to specify the features and capabilities for which SHIELD is to be considered validated, and to reference the documents that establish the validation.

  6. SHIELD 1.0: development of a shielding calculator program in diagnostic radiology; SHIELD 1.0: desenvolvimento de um programa de calculo de blindagem em radiodiagnostico

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Romulo R.; Real, Jessica V.; Luz, Renata M. da [Hospital Sao Lucas (PUCRS), Porto Alegre, RS (Brazil); Friedrich, Barbara Q.; Silva, Ana Maria Marques da, E-mail: ana.marques@pucrs.br [Pontificia Universidade Catolica do Rio Grande do Sul (PUCRS), Porto Alegre, RS (Brazil)

    2013-08-15

    In shielding calculation of radiological facilities, several parameters are required, such as occupancy, use factor, number of patients, source-barrier distance, area type (controlled and uncontrolled), radiation (primary or secondary) and material used in the barrier. The shielding design optimization requires a review of several options about the physical facility design and, mainly, the achievement of the best cost-benefit relationship for the shielding material. To facilitate the development of this kind of design, a program to calculate the shielding in diagnostic radiology was implemented, based on data and limits established by National Council on Radiation Protection and Measurements (NCRP) 147 and SVS-MS 453/98. The program was developed in C⌗ language, and presents a graphical interface for user data input and reporting capabilities. The module initially implemented, called SHIELD 1.0, refers to calculating barriers for conventional X-ray rooms. The program validation was performed by the comparison with the results of examples of shielding calculations presented in NCRP 147.

  7. The Tower Shielding Facility: Its glorious past

    Energy Technology Data Exchange (ETDEWEB)

    Muckenthaler, F.J.

    1997-05-07

    The Tower Shielding Facility (TSF) is the only reactor facility in the US that was designed and built for radiation-shielding studies in which both the reactor source and shield samples could be raised into the air to allow measurements to be made without interference from ground scattering or other spurious effects. The TSF proved its usefulness as many different programs were successfully completed. It became active in work for the Defense Atomic Support Agency (DASA) Space Nuclear Auxiliary Power, Defense Nuclear Agency, Liquid Metal Fast Breeder Reactor Program, the Gas-Cooled and High-Temperature Gas-Cooled Reactor programs, and the Japanese-American Shielding Program of Experimental Research, just to mention a few of the more extensive ones. The history of the TSF as presented in this report describes the various experiments that were performed using the different reactors. The experiments are categorized as to the programs which they supported and placed in corresponding chapters. The experiments are described in modest detail, along with their purpose when appropriate. Discussion of the results is minimal, but references are given to more extensive topical reports.

  8. The Tower Shielding Facility: Its glorious past

    International Nuclear Information System (INIS)

    The Tower Shielding Facility (TSF) is the only reactor facility in the US that was designed and built for radiation-shielding studies in which both the reactor source and shield samples could be raised into the air to allow measurements to be made without interference from ground scattering or other spurious effects. The TSF proved its usefulness as many different programs were successfully completed. It became active in work for the Defense Atomic Support Agency (DASA) Space Nuclear Auxiliary Power, Defense Nuclear Agency, Liquid Metal Fast Breeder Reactor Program, the Gas-Cooled and High-Temperature Gas-Cooled Reactor programs, and the Japanese-American Shielding Program of Experimental Research, just to mention a few of the more extensive ones. The history of the TSF as presented in this report describes the various experiments that were performed using the different reactors. The experiments are categorized as to the programs which they supported and placed in corresponding chapters. The experiments are described in modest detail, along with their purpose when appropriate. Discussion of the results is minimal, but references are given to more extensive topical reports

  9. Nuclear shielding of openings in ITER Tokamak building

    Energy Technology Data Exchange (ETDEWEB)

    Dammann, A., E-mail: alexis.dammann@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Arumugam, A.P.; Beaudoin, V.; Beltran, D.; Benchikhoune, M.; Berruyer, F.; Cortes, P.; Gandini, F. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Ghirelli, N. [ASSYSTEM E.O.S, ZAC Saint Martin, 23, rue Benjamin Franklin, 84120 Pertuis (France); Gray, A.; Hurzlmeier, H.; Le Page, M. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Lemée, A. [SOGETI High Tech, 180 Rue René Descartes, 13851 Aix en Provence (France); Lentini, G.; Loughlin, M.; Mita, Y.; Patisson, L.; Rigoni, G.; Rathi, D.; Song, I. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2013-10-15

    Highlights: ► Establishment of a methodology to design shielded opening in external wall of the Tokamak building. ► Analysis of the shielding requirement, case by case, depending on the localization and the context. ► Implementation of an integrated solution for shielded opening. -- Abstract: The external walls of the Tokamak building, made of thick concrete, provide the nuclear shielding for operators working in adjacent buildings and for the environment. There are a series of openings to these external walls, devoted to ducts or pipes for ventilation, waveguides and transmission lines for heating systems and diagnostics, cooling pipes, cable trays or busbars. The shielding properties of the wall shall be preserved by adequate design of the openings in order not to affect the radiological zoning in adjacent areas. For some of them, shielding properties of the wall are not affected because the size of the network is quite small or the source is far from the opening. But for most of the openings, specific features shall be considered. Even if the approach is the same and the ways to shield can be standardized, specific analysis is requested in any case because the constraints are different.

  10. Nuclear shielding of openings in ITER Tokamak building

    International Nuclear Information System (INIS)

    Highlights: ► Establishment of a methodology to design shielded opening in external wall of the Tokamak building. ► Analysis of the shielding requirement, case by case, depending on the localization and the context. ► Implementation of an integrated solution for shielded opening. -- Abstract: The external walls of the Tokamak building, made of thick concrete, provide the nuclear shielding for operators working in adjacent buildings and for the environment. There are a series of openings to these external walls, devoted to ducts or pipes for ventilation, waveguides and transmission lines for heating systems and diagnostics, cooling pipes, cable trays or busbars. The shielding properties of the wall shall be preserved by adequate design of the openings in order not to affect the radiological zoning in adjacent areas. For some of them, shielding properties of the wall are not affected because the size of the network is quite small or the source is far from the opening. But for most of the openings, specific features shall be considered. Even if the approach is the same and the ways to shield can be standardized, specific analysis is requested in any case because the constraints are different

  11. (n,γ)反应实验研究中的中子屏蔽设计%Neutron Shielding Design for Experiment Research of (n,γ) Reaction

    Institute of Scientific and Technical Information of China (English)

    黄兴; 贺国珠; 程品晶; 张奇纬; 周祖英

    2015-01-01

    Neutron capture cross section can be measured by Gamma-ray Total Absorption Facility (GTAF) with high precision. To reduce the background of experiments, the neutron source must be collimated and shielded, and the neutrons scattered from the sample must be absorbed to minimise interference after they go into the detector. The shield, collimator and absorber were simulated and designed with MCNP code. Boron-containing polyethylene with 3%BC4 and lead are used as the materials for the neutron collimator and shield. The diameter of the collimating aperture is 13 mm, and the length of the collimator is 500 mm. After being collimated, the diameter of neutron beam plateau at the sample position is 21 mm. The neutron absorber is made of polyethylene and BC4, and the thickness of polyethylene shell and BC4 shell are 60 and 10 mm, respectively. The simulated result shows that neutrons scattered from the sample can decay 93.7%through the neutron absorber.%用γ射线全吸收型装置(Gamma-ray Total Absorption Facility,GTAF),可以对中子俘获反应截面进行高精度测量。为了降低实验本底,实验中需要对源中子进行准直和屏蔽,还要对被样品散射的中子进行吸收以减少它们进入探测器后所形成的干扰。采用MCNP对中子的准直器、屏蔽体和中子吸收体进行了模拟设计,中子准直屏蔽体材料选用含硼聚乙烯(BC4的质量分数为3%)和铅。准直孔直径为13 mm,长度为500 mm,经准直后样品处中子束斑坪顶直径为21 mm。中子吸收体材料选用聚乙烯和碳化硼,吸收体球壳内腔半径30 mm,聚乙烯壳层厚度60 mm,碳化硼壳层厚度10 mm,被样品散射的中子经吸收体后衰减93.7%。

  12. High frequency electromagnetic interference shielding magnetic polymer nanocomposites

    Science.gov (United States)

    He, Qingliang

    Electromagnetic interference is one of the most concerned pollution and problem right now since more and more electronic devices have been extensively utilized in our daily lives. Besides the interference, long time exposure to electromagnetic radiation may also result in severe damage to human body. In order to mitigate the undesirable part of the electromagnetic wave energy and maintain the long term sustainable development of our modern civilized society, new technology development based researches have been made to solve this problem. However, one of the major challenges facing to the electromagnetic interference shielding is the relatively low shielding efficiency and the high cost as well as the complicated shielding material manufacture. From the materials science point of view, the key solutions to these challenges are strongly depended on the breakthrough of the current limit of shielding material design and manufacture (such as hierarchical material design with controllable and predictable arrangement in nanoscale particle configuration via an easy in-situ manner). From the chemical engineering point of view, the upgrading of advanced material shielding performance and the enlarged production scale for shielding materials (for example, configure the effective components in the shielding material in order to lower their usage, eliminate the "rate-limiting" step to enlarge the production scale) are of great importance. In this dissertation, the design and preparation of morphology controlled magnetic nanoparticles and their reinforced polypropylene polymer nanocomposites will be covered first. Then, the functionalities of these polymer nanocomposites will be demonstrated. Based on the innovative materials design and synergistic effect on the performance advancement, the magnetic polypropylene polymer nanocomposites with desired multifunctionalities are designed and produced targeting to the electromagnetic interference shielding application. In addition

  13. Final Technical Report [Cosmogenic background and shielding R&D for a Ge Neutrinoless Double Beta Decay Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Guiseppe, Vince

    2013-10-01

    The USD Majorana group focused all of its effort in support of the MAJORANA DEMONSTRATOR (MJD) experiment. Final designs of the shielding subsystems are complete. Construction of the MJD shielding systems at SURF has begun and the proposed activities directly support the completion of the shield systems. The PI and the group contribute heavily to the onsite construction activities of the MJD experiment. The group led investigations into neutron and neutron-­induced backgrounds, shielding effectiveness and design, and radon backgrounds.

  14. Reflective Shields for Artificial Satellites

    Science.gov (United States)

    Bouquet, F. L.

    1986-01-01

    Report proposes reflective shield that protects spacecraft from radiant energy. Also gives some protection against particle beams and cosmic rays. Conceptual shield essentially advanced version of decorative multifaceted mirror balls often hung over dance floors. Mirror facets disperse radiant energy in many directions.

  15. Calmodulin binding to recombinant myosin-1c and myosin-1c IQ peptides

    Directory of Open Access Journals (Sweden)

    Cyr Janet L

    2002-11-01

    Full Text Available Abstract Background Bullfrog myosin-1c contains three previously recognized calmodulin-binding IQ domains (IQ1, IQ2, and IQ3 in its neck region; we identified a fourth IQ domain (IQ4, located immediately adjacent to IQ3. How calmodulin binds to these IQ domains is the subject of this report. Results In the presence of EGTA, calmodulin bound to synthetic peptides corresponding to IQ1, IQ2, and IQ3 with Kd values of 2–4 μM at normal ionic strength; the interaction with an IQ4 peptide was much weaker. Ca2+ substantially weakened the calmodulin-peptide affinity for all of the IQ peptides except IQ3. To reveal how calmodulin bound to the linearly arranged IQ domains of the myosin-1c neck, we used hydrodynamic measurements to determine the stoichiometry of complexes of calmodulin and myosin-1c. Purified myosin-1c and T701-Myo1c (a myosin-1c fragment with all four IQ domains and the C-terminal tail each bound 2–3 calmodulin molecules. At a physiologically relevant temperature (25°C and under low-Ca2+ conditions, T701-Myo1c bound two calmodulins in the absence and three calmodulins in the presence of 5 μM free calmodulin. Ca2+ dissociated nearly all calmodulins from T701-Myo1c at 25°C; one calmodulin was retained if 5 μM free calmodulin was present. Conclusions We inferred from these data that at 25°C and normal cellular concentrations of calmodulin, calmodulin is bound to IQ1, IQ2, and IQ3 of myosin-1c when Ca2+ is low. The calmodulin bound to one of these IQ domains, probably IQ2, is only weakly associated. Upon Ca2+ elevation, all calmodulin except that bound to IQ3 should dissociate.

  16. The shield effect

    DEFF Research Database (Denmark)

    Toft, Søren; Albo, Maria J

    2016-01-01

    Several not mutually exclusive functions have been ascribed to nuptial gifts across different taxa. Although the idea that a nuptial prey gift may protect the male from pre-copulatory sexual cannibalism is attractive, it has previously been considered of no importance based on indirect evidence and...... rejected by experimental tests. We reinvestigated whether nuptial gifts may function as a shield against female attacks during mating encounters in the spider Pisaura mirabilis and whether female hunger influences the likelihood of cannibalistic attacks. The results showed that pre-copulatory sexual...... cannibalism was enhanced when males courted without a gift and this was independent of female hunger. We propose that the nuptial gift trait has evolved partly as a counteradaptation to female aggression in this spider species....

  17. Sulphate resistant shielding material

    International Nuclear Information System (INIS)

    The shielding material of the present invention is provided with sulfuric acid resistance and contains bentonite put to ion exchange treatment with barium ions as an effective ingredient. When mortars and concretes are exposed to the circumstance of sulfate, the effective ingredient functions to take place reaction between intruding sulfate and the barium ions to form insoluble barium sulfate thereby reducing chemical corrosion of mortars and concretes caused by sulfate. Cement materials, water and aggregates can optionally be contained in addition to bentonite and bentonite put to ion exchange treatment. Chemical corrosion of concretes and mortars due to intrusion of the sulfate can be prevented, and it is useful as an artificial barrier, for example, in radioactive active waste processing facilities. (T.M.)

  18. Welding shield for coupling heaters

    Science.gov (United States)

    Menotti, James Louis

    2010-03-09

    Systems for coupling end portions of two elongated heater portions and methods of using such systems to treat a subsurface formation are described herein. A system may include a holding system configured to hold end portions of the two elongated heater portions so that the end portions are abutted together or located near each other; a shield for enclosing the end portions, and one or more inert gas inlets configured to provide at least one inert gas to flush the system with inert gas during welding of the end portions. The shield may be configured to inhibit oxidation during welding that joins the end portions together. The shield may include a hinged door that, when closed, is configured to at least partially isolate the interior of the shield from the atmosphere. The hinged door, when open, is configured to allow access to the interior of the shield.

  19. Analysis methods for Kevlar shield response to rotor fragments

    Science.gov (United States)

    Gerstle, J. H.

    1977-01-01

    Several empirical and analytical approaches to rotor burst shield sizing are compared and principal differences in metal and fabric dynamic behavior are discussed. The application of transient structural response computer programs to predict Kevlar containment limits is described. For preliminary shield sizing, present analytical methods are useful if insufficient test data for empirical modeling are available. To provide other information useful for engineering design, analytical methods require further developments in material characterization, failure criteria, loads definition, and post-impact fragment trajectory prediction.

  20. Multihelix rotating shield brachytherapy for cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Dadkhah, Hossein [Department of Biomedical Engineering, University of Iowa, 1402 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States); Kim, Yusung; Flynn, Ryan T., E-mail: ryan-flynn@uiowa.edu [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 (United States); Wu, Xiaodong [Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242 and Department of Electrical and Computer Engineering, University of Iowa, 4016 Seamans Center for the Engineering Arts and Sciences, Iowa City, Iowa 52242 (United States)

    2015-11-15

    Purpose: To present a novel brachytherapy technique, called multihelix rotating shield brachytherapy (H-RSBT), for the precise angular and linear positioning of a partial shield in a curved applicator. H-RSBT mechanically enables the dose delivery using only linear translational motion of the radiation source/shield combination. The previously proposed approach of serial rotating shield brachytherapy (S-RSBT), in which the partial shield is rotated to several angular positions at each source dwell position [W. Yang et al., “Rotating-shield brachytherapy for cervical cancer,” Phys. Med. Biol. 58, 3931–3941 (2013)], is mechanically challenging to implement in a curved applicator, and H-RSBT is proposed as a feasible solution. Methods: A Henschke-type applicator, designed for an electronic brachytherapy source (Xoft Axxent™) and a 0.5 mm thick tungsten partial shield with 180° or 45° azimuthal emission angles and 116° asymmetric zenith angle, is proposed. The interior wall of the applicator contains six evenly spaced helical keyways that rigidly define the emission direction of the partial radiation shield as a function of depth in the applicator. The shield contains three uniformly distributed protruding keys on its exterior wall and is attached to the source such that it rotates freely, thus longitudinal translational motion of the source is transferred to rotational motion of the shield. S-RSBT and H-RSBT treatment plans with 180° and 45° azimuthal emission angles were generated for five cervical cancer patients with a diverse range of high-risk target volume (HR-CTV) shapes and applicator positions. For each patient, the total number of emission angles was held nearly constant for S-RSBT and H-RSBT by using dwell positions separated by 5 and 1.7 mm, respectively, and emission directions separated by 22.5° and 60°, respectively. Treatment delivery time and tumor coverage (D{sub 90} of HR-CTV) were the two metrics used as the basis for evaluation and

  1. Hemoglobin A1c Versus Oral Glucose Tolerance Test in Postpartum Diabetes Screening

    OpenAIRE

    Picón, María José; Murri, Mora; Muñoz, Araceli; Fernández-García, José Carlos; Gomez-Huelgas, Ricardo; Tinahones, Francisco J.

    2012-01-01

    OBJECTIVE To determine the usefulness of measuring hemoglobin A1c (A1C), alone or combined with the fasting glucose test, compared with the oral glucose tolerance test (OGTT) for the reassessment of the carbohydrate metabolism status in postpartum women with a history of gestational diabetes mellitus (GDM). RESEARCH DESIGN AND METHODS We evaluated the status of carbohydrate metabolism by performing the OGTT and fasting glucose and A1C tests in 231 postpartum women with prior GDM 1 year after ...

  2. Electrodynamic Dust Shield for Space Applications

    Science.gov (United States)

    Mackey, Paul J.; Johansen, Michael R.; Olsen, Robert C.; Raines, Matthew G.; Phillips, James R., III; Cox, Rachel E.; Hogue, Michael D.; Pollard, Jacob R. S.; Calle, Carlos I.

    2016-01-01

    Dust mitigation technology has been highlighted by NASA and the International Space Exploration Coordination Group (ISECG) as a Global Exploration Roadmap (GER) critical technology need in order to reduce life cycle cost and risk, and increase the probability of mission success. The Electrostatics and Surface Physics Lab in Swamp Works at the Kennedy Space Center has developed an Electrodynamic Dust Shield (EDS) to remove dust from multiple surfaces, including glass shields and thermal radiators. Further development is underway to improve the operation and reliability of the EDS as well as to perform material and component testing outside of the International Space Station (ISS) on the Materials on International Space Station Experiment (MISSE). This experiment is designed to verify that the EDS can withstand the harsh environment of space and will look to closely replicate the solar environment experienced on the Moon.

  3. Radioisotope Power System Facility shielding analysis

    International Nuclear Information System (INIS)

    A series of calculations for the Radioisotope Power System Facility have been performed. These analyses have determined the shielding required for storage, testing, and transport of 238Pu heat source modules using the Monte Carlo code MCNP3B. The source terms and the assumptions used have been verified by comparison of calculated dose rates with measured ones. This paper describes the methodology used for shielding designs and the utilization of available variance reduction techniques to improve the computational efficiency. The new version of MCNP (MCNP3B) with a repeated structure capability was used. It decreased the chance for computer model errors and greatly decreased the model setup time. 2 refs., 3 figs., 2 tabs

  4. Analysis for Radiation and Shielding Dose in Plasma Focus Neutron Source Using FLUKA

    Science.gov (United States)

    Nemati, M. J.; Amrollahi, R.; Habibi, M.

    2012-06-01

    Monte Carlo simulations have been performed for the attenuation of neutron radiation produced at Plasma focus (PF) devices through various shielding design. At the test site it will be fired with deuterium and tritium (D-T) fusion resulting in a yield of about 1013 fusion neutrons of 14 MeV. This poses a radiological hazard to scientists and personnel operating the device. The goal of this paper was to evaluate various shielding options under consideration for the PF operating with D-T fusion. Shields of varying neutrons-shielding effectiveness were investigated using concrete, polyethylene, paraffin and borated materials. The most effective shield, a labyrinth structure, allowed almost 1,176 shots per year while keeping personnel under 20 mSV of dose. The most expensive shield that used, square shield with 100 cm concrete thickness on the walls and Borated paraffin along with borated polyethylene added outside the concrete allowed almost 15,000 shot per year.

  5. Experimental and simulation optimization analysis of the Whipple shields against shaped charge

    Institute of Scientific and Technical Information of China (English)

    G.Hussain; A.Hameed; I.Horsfall; P.Barton; A.Q.Malik

    2012-01-01

    Occasionally,the Whipple shields are used for the protection of a space station and a satellite against the meteoroids and orbital debris.In the Whipple shields each layer of the shield depletes part of high speed projectile energy either by brealing the projectile or absorbing its energy.Similarly,this investigation uses the Whipple shields against the shaped charge to protect the light armour such as infantry fighting vehicles with a little modification in their design.The unsteady multiple interactions of shaped charge jet with the Whipple shield package against the steady homogeneous target is scrutinized to optimize the shield thickness.Simulations indicate that the shield thickness of 0.75 mm offers an optimum configuration against the shaped charge.Experiments also support this evidence.

  6. [An individual facial shield for a sportsman with an orofacial injury].

    Science.gov (United States)

    de Baat, C; Peters, R; van Iperen-Keiman, C M; de Vleeschouwer, M

    2005-05-01

    Facial shields are used when practising contact sports, high speed sports, sports using hard balls, sticks or bats, sports using protective shields or covers, and sports using hard boardings around the sports ground. Examples of facial shields are commercially available, per branch of sport standardised helmets. Fabricating individual protective shields is primarily restricted to mouth guards. In individual cases a more extensive facial shield is demanded, for instance in case of a surgically stabilised facial bone fracture. In order to be able to fabricate an extensive individual facial shield, an accurate to the nearest model of the anterior part of the head is required. An accurate model can be provided by making an impression of the face, which is poured in dental stone. Another method is producing a stereolithographic model using computertomography or magnetic resonance imaging. On the accurate model the facial shield can be designed and fabricated from a strictly safe material, such as polyvinylchloride or polycarbonate. PMID:15932045

  7. Radiation shields for a shelter

    International Nuclear Information System (INIS)

    A simple and cheap closure and radiation shield arrangement is described for the entrance of an underground shelter. The shelter can serve as a blast-proof, biological or nuclear shelter. The radiation shield is positioned above the habitable space of the shelter and below a blast-proof, dust-proof outer cover. The shield consists of a box containing a filling, e.g. coke with a concrete screed, is closed by bolted panels and is horizontally moveable by sliding on castors. (author)

  8. New Materials for EMI Shielding

    Science.gov (United States)

    Gaier, James R.

    1999-01-01

    Graphite fibers intercalated with bromine or similar mixed halogen compounds have substantially lower resistivity than their pristine counterparts, and thus should exhibit higher shielding effectiveness against electromagnetic interference. The mechanical and thermal properties are nearly unaffected, and the shielding of high energy x-rays and gamma rays is substantially increased. Characterization of the resistivity of the composite materials is subtle, but it is clear that the composite resistivity is substantially lowered. Shielding effectiveness calculations utilizing a simple rule of mixtures model yields results that are consistent with available data on these materials.

  9. Radiation shielding and safety analysis for SPring-8

    Energy Technology Data Exchange (ETDEWEB)

    Asano, Yoshihiro; Sasamoto, Nobuo [Japan Atomic Energy Research Inst., Kamigori, Hyogo (Japan). Kansai Research Establishment

    1998-03-01

    The methods of shielding design and safety analysis applied to SPring-8 are summarized. SPring-8, a third generation synchrotron radiation facility, is the facility with the highest stored electron energy of 8 GeV and very low beam emittance of 5.5 nm{center_dot}rad. Because of these distinguished features, a variety of radiation issues have to be taken up, requiring the latest information for analyses. In this technical report are described the calculational methods and the conditions for the following shielding matters as well as verification of the validity; a bulk shielding, synchrotron radiation beamline shielding, skyshine, streaming through ducts and mazes, induced activities in air, cooling water and targets, and incident analysis due to abnormal beam losses. (author)

  10. Monte Carlo simulations for optimization of neutron shielding concrete

    Science.gov (United States)

    Piotrowski, Tomasz; Tefelski, Dariusz; Polański, Aleksander; Skubalski, Janusz

    2012-06-01

    Concrete is one of the main materials used for gamma and neutron shielding. While in case of gamma rays an increase in density is usually efficient enough, protection against neutrons is more complex. The aim of this paper is to show the possibility of using the Monte Carlo codes for evaluation and optimization of concrete mix to reach better neutron shielding. Two codes (MCNPX and SPOT — written by authors) were used to simulate neutron transport through a wall made of different concretes. It is showed that concrete of higher compressive strength attenuates neutrons more effectively. The advantage of heavyweight concrete (with barite aggregate), usually used for gamma shielding, over the ordinary concrete was not so clear. Neutron shielding depends on many factors e.g. neutron energy, barrier thickness and atomic composition. All this makes a proper design of concrete as a very important issue for nuclear power plant safety assurance.

  11. Enzymatic syntheses of (1-(C-11))pyruvic acid and L-(1-(C-11))lactic acid via DL-(1-(C-11))alanine

    Energy Technology Data Exchange (ETDEWEB)

    Ropchan, J.R.; Barrio, J.R.

    1984-01-01

    L-(1-(C-11)) Lactic acid was prepared in three steps using a remote, semi-automated procedure: (1) production of DL-(1-(C-11)) alanine (2) enzymatic conversion of DL (1-(C-11)) alanine to (1-(C-11)) pyruvate and (3) enzymatic transformation of (1-(C-11)) pyruvate to L-(1-(C-11)) lactic acid. DL-(1-(C-11)) Alanine was synthesized from NCA C-11 HCN using a modification of the Bucherer-Strecker reaction. The DL-isomers were converted to (1-(C-11)) pyruvate by passage through (1) immobilized D-amino acid oxidase enzyme column followed by (2) immobilized L-alanine dehydrogenase (l-ADH) enzyme column. (1-(C-11)) Pyruvate was then transformed to L-(1-(C-11)) lactic acid by elution through a L-lactic dehydrogenase enzyme column. These enzyme columns are reusable beyond three months, give high radiochemical purity (>98%), eliminate the possibility of protein contamination, assure sterile, pyrogen-free products and allow rapid separation and quantitative conversion of DL-isomers to the desired products. Typically the synthesis required 30-40 min after cyclotron production of NCA C-11 HCN with radiochemical yields of 15-25 mCi (23%) of L-(1-(C-11)) lactic acid and 20-35 mCi (33%) of (l-(C-11)) pyruvic acid starting with 250-400 mCi of C-11 HCN. Also 10-20 mCi (19%) of L-(1-(C-11)) alanine was produced by resin separation (AG50W-X8), H/sup +/ form of (1-(C-11)) pyruvate and L-(1-(C-11)) alanine following elution through D-AAO enzyme column. The radiochemical purities of (1-(C-11)) pyruvic acid, L-(1-(C-11)) lactic acid and L-(1-(C-11)) alanine were verified routinely by reversed-phase HPLC.

  12. 泥水盾构机泥水循环从站控制系统的设计%Design of slave station control system for slurry circulation in slurry shield machine

    Institute of Scientific and Technical Information of China (English)

    安冬云; 廖潇; 寇宝庆; 张华芬; 张树凯

    2013-01-01

    Taking the Herrenknecht shield machine as an example,a slave station control system for slurry circulation,independent from the master station control system,is designed to seamlessly connect to the shield machine control system.The slave station is composed of slurry pump control cabinet,valve control box and ground monitoring station.The S7200PLC is selected for the control and the Profibus-DP is used for communication with the master station.In ground monitoring station,a combination of S7-200PLC+Profibus-DP modulus+computer terminal is designed to synchronously display the operation conditions of pumps and valves.The slurry pump is driven by AC motor,with its speed controlled by a schnielder Altivar 71 frequency convertor,a Proflbus-DP communication card and a S7-200PLC.The Profibus-DP network and Siemens S7 series PLC are utilized to construct the overall system with twin-core CAT 5 cable as the transmission media in the bus,with the transmission speed up to 12 MBP.Optoelectronic isolation relay amplifiers are added in every local control cabinet,which can solve the problems in long-distance shield tunneling communication signal transmission attenuation and electrical safety in the tunnel.(3 Figures,2 References)%以海瑞克盾构机为例,设计了泥水循环从站控制系统,使其与盾构机控制系统无缝连接,并独立于主站控制系统.各泥浆泵控制柜、阀门控制箱、地面监控站为从站结构,选用S7-200PLC控制,通过Profibus-DP现场总线与主站通讯;地面监控站采用S7-200PLC+ Profibus-DP模块+计算机终端,同步显示远程控制站的泵、阀运行状态;泥浆泵驱动电机选用交流电机,调速控制采用schnielder Altivar 71变频器+ Profibus-DP通讯卡+S7-200PLC;采用Profibus-DP网络和西门子S7系列PLC搭建整个系统,总线采用2芯5类电缆作为传输介质,通讯速度可达12 MBP;在本地控制柜增加光电隔离中继放大器,解决长距离盾构隧道掘进通讯信号

  13. SNF shipping cask shielding analysis

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.O.; Pace, J.V. III

    1996-01-01

    The Waste Management and Remedial Action Division has planned a modification sequence for storage facility 7827 in the Solid Waste Storage Area (SWSA). The modification cycle is: (1) modify an empty caisson, (2) transfer the spent nuclear fuel (SNF) of an occupied caisson to a hot cell in building 3525 for inspection and possible repackaging, and (3) return the package to the modified caisson in the SWSA. Although the SNF to be moved is in the solid form, it has different levels of activity. Thus, the following 5 shipping casks will be available for the task: the Loop Transport Carrier, the In- Pile Loop LITR HB-2 Carrier, the 6.5-inch HRLEL Carrier, the HFIR Hot Scrap Carrier, and the 10-inch ORR Experiment Removal Shield Cask. This report describes the shielding tasks for the 5 casks: determination of shielding characteristics, any streaming avenues, estimation of thermal limits, and shielding calculational uncertainty for use in the transportation plan.

  14. Shielding of moving line charges

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Youmei; He, Bingyu [Department of Physics, School of Science, Hangzhou Dianzi University, Hangzhou 310018 (China); Yu, Wei [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Yu, M.Y., E-mail: myyu@zju.edu.cn [Institute for Fusion Theory and Simulation and Department of Physics, Zhejiang University, Hangzhou 310027 (China); Institute for Theoretical Physics I, Ruhr University, D-44780 Bochum (Germany)

    2015-07-03

    A charged object moving in plasma can excite plasma waves that inevitably modify its Debye shielding characteristics. When the excited waves propagate sufficiently fast, the shielding can even break down. Here the properties of finite amplitude plasma waves excited by a moving line charge are investigated. It is found that when the speed of the latter is close to but less than the thermal speed of the background plasma electrons, only a localized disturbance in the form of a soliton that moves together with the line charge is excited. That is, the line charge is well shielded even though it is moving at a high speed and has generated a large local electrostatic field. However, for a pair of line charges moving together, such complete shielding behavior could not be found.

  15. Upgrade of the LHC magnet interconnections thermal shielding

    Science.gov (United States)

    Musso, Andrea; Barlow, Graeme; Bastard, Alain; Charrondiere, Maryline; Chrul, Anna; Damianoglou, Dimitrios; Deferne, Guy; Dib, Gaëlle; Duret, Max; Guinchard, Michael; Prin, Hervé; Strychalski, Michał; Craen, Arnaud Vande; Villiger, Gilles; Wright, Loren

    2014-01-01

    The about 1700 interconnections (ICs) between the Large Hadron Collider (LHC) superconducting magnets include thermal shielding at 50-75 K, providing continuity to the thermal shielding of the magnet cryostats to reduce the overall radiation heat loads to the 1.9 K helium bath of the magnets. The IC shield, made of aluminum, is conduction-cooled via a welded bridge to the thermal shield of the adjacent magnets which is actively cooled. TIG welding of these bridges made in the LHC tunnel at installation of the magnets induced a considerable risk of fire hazard due to the proximity of the multi-layer insulation of the magnet shields. A fire incident occurred in one of the machine sectors during machine installation, but fortunately with limited consequences thanks to prompt intervention of the operators. LHC is now undergoing a 2 years technical stop during which all magnet's ICs will have to be opened to consolidate the magnet electrical connections. The IC thermal shields will therefore have to be removed and re-installed after the work is completed. In order to eliminate the risk of fire hazard when re-welding, it has been decided to review the design of the IC shields, by replacing the welded bridges with a mechanical clamping which also preserves its thermal function. An additional advantage of this new solution is the ease in dismantling for maintenance, and eliminating weld-grinding operations at removal needing radioprotection measures because of material activation after long-term operation of the LHC. This paper describes the new design of the IC shields and in particular the theoretical and experimental validation of its thermal performance. Furthermore a status report of the on-going upgrade work in the LHC is given.

  16. Shielding vacuum fluctuations with graphene

    OpenAIRE

    Ribeiro, Sofia; Scheel, Stefan

    2013-01-01

    The Casimir-Polder interaction of ground-state and excited atoms with graphene is investigated with the aim to establish whether graphene systems can be used as a shield for vacuum fluctuations of an underlying substrate. We calculate the zero-temperature Casimir-Polder potential from the reflection coefficients of graphene within the framework of the Dirac model. For both doped and undoped graphene we show limits at which graphene could be used effectively as a shield. Additional results are...

  17. Composite Aerogel Multifoil Protective Shielding

    Science.gov (United States)

    Jones, Steven M.

    2013-01-01

    New technologies are needed to survive the temperatures, radiation, and hypervelocity particles that exploration spacecraft encounter. Multilayer insulations (MLIs) have been used on many spacecraft as thermal insulation. Other materials and composites have been used as micrometeorite shielding or radiation shielding. However, no material composite has been developed and employed as a combined thermal insulation, micrometeorite, and radiation shielding. By replacing the scrims that have been used to separate the foil layers in MLIs with various aerogels, and by using a variety of different metal foils, the overall protective performance of MLIs can be greatly expanded to act as thermal insulation, radiation shielding, and hypervelocity particle shielding. Aerogels are highly porous, low-density solids that are produced by the gelation of metal alkoxides and supercritical drying. Aerogels have been flown in NASA missions as a hypervelocity particle capture medium (Stardust) and as thermal insulation (2003 MER). Composite aerogel multifoil protective shielding would be used to provide thermal insulation, while also shielding spacecraft or components from radiation and hypervelocity particle impacts. Multiple layers of foil separated by aerogel would act as a thermal barrier by preventing the transport of heat energy through the composite. The silica aerogel would act as a convective and conductive thermal barrier, while the titania powder and metal foils would absorb and reflect the radiative heat. It would also capture small hypervelocity particles, such as micrometeorites, since it would be a stuffed, multi-shock Whipple shield. The metal foil layers would slow and break up the impacting particles, while the aerogel layers would convert the kinetic energy of the particles to thermal and mechanical energy and stop the particles.

  18. Internal Calibration of HJ-1-C Satellite SAR System

    Directory of Open Access Journals (Sweden)

    Yang Zhen

    2014-06-01

    Full Text Available The HJ-1-C satellite is a Synthetic Aperture Radar (SAR satellite of a small constellation for environmental and disaster monitoring. At present, it is in orbit and working well. The SAR system uses a mesh reflector antenna and centralized power amplifier, and has an internal calibration function in orbit. This study introduces the internal calibration modes and signal paths. The design and realization of the internal calibrator are discussed in detail. Finally, the internal calibration data acquired in orbit are also analyzed.

  19. Shielding requirements in helical tomotherapy

    International Nuclear Information System (INIS)

    Helical tomotherapy is a relatively new intensity-modulated radiation therapy (IMRT) treatment for which room shielding has to be reassessed for the following reasons. The beam-on-time needed to deliver a given target dose is increased and leads to a weekly workload of typically one order of magnitude higher than that for conventional radiation therapy. The special configuration of tomotherapy units does not allow the use of standard shielding calculation methods. A conventional linear accelerator must be shielded for primary, leakage and scatter photon radiations. For tomotherapy, primary radiation is no longer the main shielding issue since a beam stop is mounted on the gantry directly opposite the source. On the other hand, due to the longer irradiation time, the accelerator head leakage becomes a major concern. An analytical model based on geometric considerations has been developed to determine leakage radiation levels throughout the room for continuous gantry rotation. Compared to leakage radiation, scatter radiation is a minor contribution. Since tomotherapy units operate at a nominal energy of 6 MV, neutron production is negligible. This work proposes a synthetic and conservative model for calculating shielding requirements for the Hi-Art II TomoTherapy unit. Finally, the required concrete shielding thickness is given for different positions of interest

  20. Designs of Antimagnetic Shield Box to Use Micro Injection Pump in Magnetic Resonance Image Formation%一种核磁共振成像中微量注射泵防磁屏蔽箱的设计

    Institute of Scientific and Technical Information of China (English)

    徐新民; 胡军智

    2011-01-01

    Objective To design one kind of antimagnetic shield box which is able to use the micro injection pump's in the MR1 strong magnetic field environment. Methods With electromagnetic screen mechanism, ihe non -ferromagnetic material was used to process the cuboid box. Whose size was proper to contain a conventional micro injection pump. Protective measures were taken to the operation hole, infusion connecting pipe and the seam beside the door, ihus enabling it to be antimagnetie and isolated. Results This method avoided the conventional MR1 magnetic field on the magnetization of the role of micro-injection pump, and the MRI image quality were not affected. Conclusion In the MRI environment, this antimagnelic shield box can cause the conventional micro injection pump to use normally under the effective addressing MRI environment, which solve the problem of inaccurate medicine given by manpower. It also expands the use scope of conventional micro injection pump, and enhances the working efficiency as well as saves the massive manpower and themedical resources.%目的:设计一种在MRI强磁场环境中能使用微量注射采的防磁屏蔽箱.方法:利用电磁屏蔽机制,采用非铁磁性材料加工成长方体箱子,其大小适合,正好能放进一台常规微量注射泵,对操作孔、输注连接管出孔、门边缝加装防护措施,使其对磁场具有很好的防磁、隔离作用.结果:该装置避免了MRI磁场对常规微量注射泵的磁化作用,使其在MRI环境中正常使用并对MRI图像质量无任何影响.结论:该防磁屏蔽箱有效解决了MRI环境下人工给药不精准的难题,扩大了常规微量注射泵的使用范围;而且提高了MRI强磁场环境中输注给药的工作效率,节约了大量的人力和医疗资源.

  1. TMC-1C: an accreting starless core

    CERN Document Server

    Schnee, S; Goodman, A; Arce, H G; Ballesteros-Paredes, J; Kuchibhotla, K

    2007-01-01

    We have mapped the starless core TMC-1C in a variety of molecular lines with the IRAM 30m telescope. High density tracers show clear signs of self-absorption and sub-sonic infall asymmetries are present in N2H+ (1-0) and DCO+ (2-1) lines. The inward velocity profile in N2H+ (1-0) is extended over a region of about 7,000 AU in radius around the dust continuum peak, which is the most extended ``infalling'' region observed in a starless core with this tracer. The kinetic temperature (~12 K) measured from C17O and C18O suggests that their emission comes from a shell outside the colder interior traced by the mm continuum dust. The C18O (2-1) excitation temperature drops from 12 K to ~10 K away from the center. This is consistent with a volume density drop of the gas traced by the C18O lines, from ~4x10^4 cm^-3 towards the dust peak to ~6x10^3 cm^-3 at a projected distance from the dust peak of 80" (or 11,000 AU). The column density implied by the gas and dust show similar N2H+ and CO depletion factors (f_D < 6)...

  2. Review of ORNL-TSF shielding experiments for the gas-cooled Fast Breeder Reactor Program

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, L.S.; Ingersoll, D.T.; Muckenthaler, F.J.; Slater, C.O.

    1982-01-01

    During the period between 1975 and 1980 a series of experiments was performed at the ORNL Tower Shielding Facility in support of the shield design for a 300-MW(e) Gas Cooled Fast Breeder Demonstration Plant. This report reviews the experiments and calculations, which included studies of: (1) neutron streaming in the helium coolant passageways in the GCFR core; (2) the effectiveness of the shield designed to protect the reactor grid plate from radiation damage; (3) the adequacy of the radial shield in protecting the PCRV (prestressed concrete reactor vessel) from radiation damage; (4) neutron streaming between abutting sections of the radial shield; and (5) the effectiveness of the exit shield in reducing the neutron fluxes in the upper plenum region of the reactor.

  3. Optimized Design for Monolayer Shield Blocking Tee Structure%单层护板封堵三通力学行为分析与结构优化

    Institute of Scientific and Technical Information of China (English)

    邵将; 田家林; 范哲; 杨琳; 庞小林; 李双双; 董超群

    2013-01-01

    Based on sealed pipe tee on-site construction mechanical properties calculation,in combination with the test pressure of the plugging process and contact problems,the calculation results of data was analyze in order to establish the optimization function,carry out multi design variables optimization to achieve optimal design of the existing structure,and thus automatically re-generate optimization model,and complete the mechanical properties calculation and the strength analysis of the optimization model.The research results show that the optimized solution not only saves raw materials,also cuts maximum stress down by 29%.At the same time,the methods and results of the study can be used for the evaluation and optimization of the safety of the pipeline construction,and have guiding significance on site production.%结合封堵过程的试验压力、接触等问题,在完成封堵三通现场施工力学性能计算的基础上,对计算结果进行数据分析,建立优化函数,进行多设计变量优化,实现现有结构的最优设计,并重新自动生成优化模型,完成优化模型力学性能计算与强度分析.研究结果表明:优化后的方案不仅节省原料,还使得最大应力下降了29%.该研究方法与结果可用于管道施工的安全评价与优化,对现场生产具有指导意义.

  4. Analysis list: Jmjd1c [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Jmjd1c Pluripotent stem cell + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Jmj...d1c.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Jmjd1c.5.tsv http://dbarchive.biosc...iencedbc.jp/kyushu-u/mm9/target/Jmjd1c.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Jmjd1c.Plu

  5. Analysis list: Myo1c [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Myo1c Embryonic fibroblast + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/My...o1c.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Myo1c.5.tsv http://dbarchive.bioscienc...edbc.jp/kyushu-u/mm9/target/Myo1c.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Myo1c.Embryonic

  6. FIRE-RESISTANT SHIELDING COATING BASED ON SHUNGITE-CONTAINING PAINT

    OpenAIRE

    BELOUSOVA Elena Sergeevna; NASONOVA Natalia Viktorovna; LYNKOV Leonid Mihailovich; BORBOTKO Timofei Valentinovich; LISOVSKIY Dmitriy Nikolaevich

    2013-01-01

    Today when specific shielded facilities are designed the construction materials and shields should meet a range of fire safety requirements. A composite coating on the basis of a water-based fire-resistant paint filled with shungite nanopowder can be applied onto walls, floors, ceilings and other surfaces in the shielded areas to reduce electromagnetic radiation and simultaneously to ensure fire safety. Shungit is a mineral with multilayer carbon fullerene globules which diameter is 10–30 nm....

  7. The vertical shaft construction technology of cutter head transformation of large diameter shield

    Institute of Scientific and Technical Information of China (English)

    He Feng; Wang Ying; Wang Zhenfei; Wang Baiquan

    2012-01-01

    Taking vertical shaft construction of cutter transformation of the Beijing underground diameter shield for ex- ample, the design and construction of cutter structure transformation under complex boundary conditions for large diameter shield were discussed. Practice about how to ensure the structure safety of the shaft as well as well-coordinated shield construction was explored, and reliable solutions were provided successfully, which can provide reference for similar projects.

  8. Study of Neutron and Gamma Radiation Protective Shield

    Directory of Open Access Journals (Sweden)

    Eskandar Asadi Amirabadi

    2013-08-01

    Full Text Available Due to the development of nuclear technology and use of these technologies in various fields of industry, medicine, research and etc, protection against radioactive rays is one of the most important topics in this field .The purpose of this is to reduce the dose rate from radioactive sources. The sources in terms of components are emitted various types of nuclear radiation with different energies. These radiations are involving of alpha particles, beta, and neutron and gamma radiation. Given that alpha and beta particles can be fully absorbed by the shield, the main issue in the debate protection radioactive rays is stopping of gamma rays and neutrons. Accordingly in shield design usually two types of radiation should be considered. First, X-rays and gamma rays, which have great influence, and by the mass of any suitable material, can be more efficiently attenuate the higher the density, the better the potential attenuation effect against gamma rays and the required shielding thickness decreases. The second type of radiation is neutrons. Often a combination of three materials is desirable that include heavy metals, light metals, and neutron-absorbing material to omit the slow neutrons through adsorption to the neutron shield. There are different materials that can be used to shielding against radioactive rays. The main materials that are used in protection include: water, lead, graphite, iron, compounds that contains B, concrete, and polyethylene. Accordingly, the main objective of this paper is evaluating the kind of shield against gamma and neutrons rays.

  9. Radiation Shielding Analysis of Electron Beam Accelerator Facility

    International Nuclear Information System (INIS)

    The objective of this technical report are to establish the radiation shielding technology of a high-energy electron accelerator to the facilities which utilize with electron beam. The technologies of electron beam irradiation(300 KeV -10 MeV) demand on the diverse areas of material processing, surface treatment, treatments on foods or food processing, improvement of metal properties, semiconductors, and ceramics, sterilization of medical goods and equipment, treatment and control of contamination and pollution, and so on. In order to acquire safety design for the protection of personnel from the radiations produced by electron beam accelerators, it is important to develop the radiation shielding analysis technology. The shielding analysis are carried out by which define source term, calculation modelling and computer calculations for 2 MeV and 10 MeV accelerators. And the shielding analysis for irradiation dump shield with 10 MeV accelerators are also performed by solving the complex 3-D geometry and long computer run time problem. The technology development of shielding analysis will be contributed to extend the further high energy accelerator development

  10. Waterproofing Design for Shield Tunnels on High-Speed Railways%高速铁路盾构隧道防水设计

    Institute of Scientific and Technical Information of China (English)

    邓朝辉

    2013-01-01

    根据高速铁路的运营养护特点,在广深港高速铁路狮子洋隧道设计过程中提出了盾构管片接缝防水采用双道密封与分区隔断的防水技术方案.文章针对弹性密封垫防水特点,分析了弹性密封垫及分区防水的关键技术参数,并针对弹性密封垫的正常工作状态,提出了接缝的错台量、张开量及施工期沟槽修补要求.%Considering the characteristics of operation and maintenance of high-speed railways, an option featuring a double seal and partition separation was adopted in the waterproofing design for the segment joint in the Shiziyang Tunnel on the Guangzhou-Shenzhen-Hongkong high-speed railway. The key technical parameters of an elastic seal gasket and partition separation are analyzed in regard to waterproofing, and the requirements for joint staggering, joint opening, and groove repair during construction are addressed.

  11. Design, fabrication, and testing of gadolinium-shielded metal fuel samples in the hydraulic tube of the high flux isotope reactor

    International Nuclear Information System (INIS)

    The use of hydraulic rabbit capsules inserted into and ejected from the core of the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) during full power operation allows for precise control of the neutron fluence in fueled experiments. Rabbit capsules with strong thermal neutron absorbers must be used to screen out thermal neutrons, thereby reducing the heat generation rate while maintaining the fast neutron flux that produces displacement damage similar to fast reactor type conditions. However, rapid insertion and ejection of rabbit capsules containing a strong neutron absorber causes a reactivity response in the reactor that has the potential to engage the HFIR safety response system which could result in an unplanned shutdown. Therefore, a set of tests were performed to provide the data needed to establish limits on the reactivity worth that can be ejected from the hydraulic facility without causing a reactor shutdown. This paper will describe the design, operation, and results of the reactivity measurements undertaken to understand the reactor response to insertion of the gadolinium-lined rabbit capsules. (author)

  12. Applicability of the three-dimensional transport code Tort to the shielding analysis of the prototype FBR Monju

    International Nuclear Information System (INIS)

    Shielding design of Monju was performed in 1980's by using the two-dimensional discrete ordinates transport code, DOT3.5. In view of complexity of the three-dimensional shielding geometry of Monju, the three-dimensional discrete ordinates transport code, TORT(2), has been applied to shielding measurement analyses of Monju in an attempt to prove practical usefulness of the code and to learn how much margin is associated with the shielding design performed by DOT3.5. This study has confirmed that TORT can practically be applied to the shielding measurement analyses of Monju, and has provided significant improvement in calculation accuracy thanks to its three-dimensional geometry employed, making the code applicable to the Monju shielding design evaluation analyses together with pre- and post-analyses of the shielding measurement now being planned. (authors)

  13. Applicability of the three-dimensional transport code Tort to the shielding analysis of the prototype FBR Monju

    Energy Technology Data Exchange (ETDEWEB)

    Takako, Shiraki [Mitsubishi Heavy Industries, Ltd (Japan); Shin, Usami; Zenro, Suzuoki; Takehide, Deshimaru [Japan Nuclear Cycle Development Institute (Japan); Kenji, Sasaki; Keiko, Tada; Hitoshi, Yokobori [Advanced Reactor Technology Co., Ltd (Japan)

    2003-07-01

    Shielding design of Monju was performed in 1980's by using the two-dimensional discrete ordinates transport code, DOT3.5. In view of complexity of the three-dimensional shielding geometry of Monju, the three-dimensional discrete ordinates transport code, TORT(2), has been applied to shielding measurement analyses of Monju in an attempt to prove practical usefulness of the code and to learn how much margin is associated with the shielding design performed by DOT3.5. This study has confirmed that TORT can practically be applied to the shielding measurement analyses of Monju, and has provided significant improvement in calculation accuracy thanks to its three-dimensional geometry employed, making the code applicable to the Monju shielding design evaluation analyses together with pre- and post-analyses of the shielding measurement now being planned. (authors)

  14. Deep-penetration calculations in concrete and iron for shielding of proton therapy accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Sheu, Rong-Jiun, E-mail: rjsheu@mx.nthu.edu.tw [Institute of Nuclear Engineering and Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China); National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 300, Taiwan (China); Chen, Yen-Fu [Department of Engineering and System Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China); Lin, Uei-Tyng [Institute of Radiological Sciences, Tzu Chi College of Technology, 880 Sec. 2, Chien-Kuo Road, Hualien 970, Taiwan (China); Jiang, Shiang-Huei [Institute of Nuclear Engineering and Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, 101 Sec. 2, Kung Fu Road, Hsinchu 300, Taiwan (China)

    2012-06-01

    Proton accelerators in the energy range of approximately 200 MeV have become increasingly popular for cancer treatment in recent years. These proton therapy facilities usually involve bulky concrete or iron in their shielding design or accelerator structure. Simple shielding data, such as source terms or attenuation lengths for various proton energies and materials are useful in designing accelerator shielding. Understanding the appropriateness or uncertainties associated with these data, which are largely generated from Monte Carlo simulations, is critical to the quality of a shielding design. This study demonstrated and investigated the problems of deep-penetration calculations on the estimation of shielding parameters through an extensive comparison between the FLUKA and MCNPX calculations for shielding against a 200-MeV proton beam hitting an iron target. Simulations of double-differential neutron production from proton bombardment were validated by comparison with experimental data. For the concrete shielding, the FLUKA calculated depth-dose distributions were consistent with the MCNPX results, except for some discrepancies in backward directions. However, for the iron shielding, if FLUKA is used inappropriately then overestimation of neutron attenuation can be expected as shown by this work because of the multigroup treatment for low-energy neutrons in FLUKA. Two neutron energy group structures, three degrees of self-shielding correction, and two iron compositions were considered in this study. Significant variation of the resulting attenuation lengths indicated the importance of problem-dependent multigroup cross sections and proper modeling of iron composition in deep-penetration calculations.

  15. Description of Transport Codes for Space Radiation Shielding

    Science.gov (United States)

    Kim, Myung-Hee Y.; Wilson, John W.; Cucinotta, Francis A.

    2011-01-01

    This slide presentation describes transport codes and their use for studying and designing space radiation shielding. When combined with risk projection models radiation transport codes serve as the main tool for study radiation and designing shielding. There are three criteria for assessing the accuracy of transport codes: (1) Ground-based studies with defined beams and material layouts, (2) Inter-comparison of transport code results for matched boundary conditions and (3) Comparisons to flight measurements. These three criteria have a very high degree with NASA's HZETRN/QMSFRG.

  16. Radiation Shielding Materials and Containers Incorporating Same

    Energy Technology Data Exchange (ETDEWEB)

    Mirsky, Steven M.; Krill, Stephen J.; and Murray, Alexander P.

    2005-11-01

    An improved radiation shielding material and storage systems for radioactive materials incorporating the same. The PYRolytic Uranium Compound (''PYRUC'') shielding material is preferably formed by heat and/or pressure treatment of a precursor material comprising microspheres of a uranium compound, such as uranium dioxide or uranium carbide, and a suitable binder. The PYRUC shielding material provides improved radiation shielding, thermal characteristic, cost and ease of use in comparison with other shielding materials. The shielding material can be used to form containment systems, container vessels, shielding structures, and containment storage areas, all of which can be used to house radioactive waste. The preferred shielding system is in the form of a container for storage, transportation, and disposal of radioactive waste. In addition, improved methods for preparing uranium dioxide and uranium carbide microspheres for use in the radiation shielding materials are also provided.

  17. EMPLACEMENT DRIFT SHIELDING CALCULATION

    Energy Technology Data Exchange (ETDEWEB)

    A. Nielsen

    1999-10-13

    The purpose of this analysis is to determine the structural response of a TRIGA Department of Energy (DOE) spent nuclear fuel (SNF) codisposal canister placed in a 5-Defense High Level Waste (DHLW) waste package (WP) and subjected to a tipover design basis event (DBE) dynamic load; the results will be reported in terms of displacements and stress magnitudes. This activity is associated with the WP design.

  18. System for imaging plutonium through heavy shielding

    International Nuclear Information System (INIS)

    A single pinhole can be used to image strong self-luminescent gamma-ray sources such as plutonium on gamma scintillation (Anger) cameras. However, if the source is weak or heavily shielded, a poor signal to noise ratio can prevent acquisition of the image. An imaging system designed and built at Los Alamos National Laboratory uses a coded aperture to image heavily shielded sources. The paper summarizes the mathematical techniques, based on the Fast Delta Hadamard transform, used to decode raw images. Practical design considerations such as the phase of the uniformly redundant aperture and the encoded image sampling are discussed. The imaging system consists of a custom designed m-sequence coded aperture, a Picker International Corporation gamma scintillation camera, a LeCroy 3500 data acquisition system, and custom imaging software. The paper considers two sources - 1.5 mCi 57Co unshielded at a distance of 27 m and 220 g of bulk plutonium (11.8% 240Pu) with 0.3 cm lead, 2.5 cm steel, and 10 cm of dense plastic material at a distance of 77.5 cm. Results show that the location and geometry of a source hidden in a large sealed package can be determined without having to open the package. 6 references, 4 figures

  19. Analytical-HZETRN Model for Rapid Assessment of Active Magnetic Radiation Shielding

    Science.gov (United States)

    Washburn, S. A.; Blattnig, S. R.; Singleterry, R. C.; Westover, S. C.

    2014-01-01

    The use of active radiation shielding designs has the potential to reduce the radiation exposure received by astronauts on deep-space missions at a significantly lower mass penalty than designs utilizing only passive shielding. Unfortunately, the determination of the radiation exposure inside these shielded environments often involves lengthy and computationally intensive Monte Carlo analysis. In order to evaluate the large trade space of design parameters associated with a magnetic radiation shield design, an analytical model was developed for the determination of flux inside a solenoid magnetic field due to the Galactic Cosmic Radiation (GCR) radiation environment. This analytical model was then coupled with NASA's radiation transport code, HZETRN, to account for the effects of passive/structural shielding mass. The resulting model can rapidly obtain results for a given configuration and can therefore be used to analyze an entire trade space of potential variables in less time than is required for even a single Monte Carlo run. Analyzing this trade space for a solenoid magnetic shield design indicates that active shield bending powers greater than 15 Tm and passive/structural shielding thicknesses greater than 40 g/cm2 have a limited impact on reducing dose equivalent values. Also, it is shown that higher magnetic field strengths are more effective than thicker magnetic fields at reducing dose equivalent.

  20. Radiation shielding for future space exploration missions

    Science.gov (United States)

    DeWitt, Joel Michael

    Scope and Method of Study. The risk to space crew health and safety posed by exposure to space radiation is regarded as a significant obstacle to future human space exploration. To countermand this risk, engineers and designers in today's aerospace community will require detailed knowledge of a broad range of possible materials suitable for the construction of future spacecraft or planetary surface habitats that provide adequate protection from a harmful space radiation environment. This knowledge base can be supplied by developing an experimental method that provides quantitative information about a candidate material's space radiation shielding efficacy with the understanding that (1) shielding is currently the only practical countermeasure to mitigate the effects of space radiation on human interplanetary missions, (2) any mass of a spacecraft or planetary surface habitat necessarily alters the incident flux of ionizing radiation on it, and (3) the delivery of mass into LEO and beyond is expensive and therefore may benefit from the possible use of novel multifunctional materials that could in principle reduce cost as well as ionizing radiation exposure. The developed method has an experimental component using CR-39 PNTD and Al2O3:C OSLD that exposes candidate space radiation shielding materials of varying composition and depth to a representative sample of the GCR spectrum that includes 1 GeV 1H and 1 GeV/n 16O, 28Si, and 56Fe heavy ion beams at the BNL NSRL. The computer modeling component of the method used the Monte Carlo radiation transport code FLUKA to account for secondary neutrons that were not easily measured in the laboratory. Findings and Conclusions. This study developed a method that quantifies the efficacy of a candidate space radiation shielding material relative to the standard of polyethylene using a combination of experimental and computer modeling techniques. The study used established radiation dosimetry techniques to present an empirical

  1. Status of reactor shielding research in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Bartine, D.E.

    1983-01-01

    Shielding research in the United States continues to place emphasis on: (1) the development and refinement of shielding design calculational methods and nuclear data; and (2) the performance of confirmation experiments, both to evaluate specific design concepts and to verify specific calculational techniques and input data. The successful prediction of the radiation levels observed within the now-operating Fast Flux Test Facility (FFTF) has demonstrated the validity of this two-pronged approach, which has since been applied to US fast breeder reactor programs and is now being used to determine radiation levels and possible further shielding needs at operating light water reactors, especially under accident conditions. A similar approach is being applied to the back end of the fission fuel cycle to verify that radiation doses at fuel element storage and transportation facilities and within fuel reprocessing plants are kept at acceptable levels without undue economic penalties.

  2. An evaluation of costs for constructing high density concrete shields at 105-K

    Energy Technology Data Exchange (ETDEWEB)

    Davis, H.S.

    1955-11-07

    The primary purpose of this report is to present cost data associated with the recent construction of biological shields at Hanford. These data are useful for analyzing shields which have been built during the past four years and for ascertaining ways to improve future designs. Specifically, the objectives of this study are to: compile and analyze cost data associated with the construction of the high density concrete shields at 105-K and the steel-masonite shields at 105-C; and determine unit costs for erecting steel forms at Hanford and for filling them with high density concrete.

  3. Improving electrical equipment and control systems for shield integrated mining systems

    Energy Technology Data Exchange (ETDEWEB)

    Rabinovich, Z.M.; Starikov, B.Ya.; Kibrik, I.S.

    1984-06-01

    The design and operation are discussed for electrical equipment and control systems for the 1AShchM, the ANShch and the 2ANShch shield integrated face systems consisting of shield supports, coal plow and chain conveyor. The shield system is used for mining inclined and steep coal seams endangered by coal dust explosions, methane or rock bursts. Control and electrical system for 3 types of shield face mining systems is similar. It cuts energy supply when methane content at working faces exceeds the maximum permissible level, controls haulage rate and cutting rate of a coal plow, controls operation of shield supports (using the Sirena system), controls dust suppression system and its water consumption. The system is also equipped with communications equipment. Tests of the control and electrical system for the integrated shield system carried out in the im. Gagarin mine in the Ukraine are described. The VAUS III control system developed by Dongiprouglemash was tested.

  4. News from the Library: Facilitating access to a program for radiation shielding - the Library can help

    CERN Multimedia

    CERN Library

    2013-01-01

    MicroShield® is a comprehensive photon/gamma ray shielding and dose assessment programme. It is widely used for designing shields, estimating source strength from radiation measurements, minimising exposure to people, and teaching shielding principles.   Integrated tools allow the graphing of results, material and source file creation, source inference with decay (dose-to-Bq calculations accounting for decay and daughter buildup), the projection of exposure rate versus time as a result of decay, access to material and nuclide data, and decay heat calculations. The latest version is able to export results using Microsoft Office (formatted and colour-coded for readability). Sixteen geometries accommodate offset dose points and as many as ten standard shields plus source self-shielding and cylinder cladding are available. The library data (radionuclides, attenuation, build-up and dose conversion) reflect standard data from ICRP 38 and 107* as well as ANSI/ANS standards and RSICC publicat...

  5. EXPERIMENTAL EVALUATION OF THE THERMAL PERFORMANCE OF A WATER SHIELD FOR A SURFACE POWER REACTOR

    Energy Technology Data Exchange (ETDEWEB)

    REID, ROBERT S. [Los Alamos National Laboratory; PEARSON, J. BOSIE [Los Alamos National Laboratory; STEWART, ERIC T. [Los Alamos National Laboratory

    2007-01-16

    Water based reactor shielding is being investigated for use on initial lunar surface power systems. A water shield may lower overall cost (as compared to development cost for other materials) and simplify operations in the setup and handling. The thermal hydraulic performance of the shield is of significant interest. The mechanism for transferring heat through the shield is natural convection. Natural convection in a 100 kWt lunar surface reactor shield design is evaluated with 2 kW power input to the water in the Water Shield Testbed (WST) at the NASA Marshall Space Flight Center. The experimental data from the WST is used to validate a CFD model. Performance of the water shield on the lunar surface is then predicted with a CFD model anchored to test data. The experiment had a maximum water temperature of 75 C. The CFD model with 1/6-g predicts a maximum water temperature of 88 C with the same heat load and external boundary conditions. This difference in maximum temperature does not greatly affect the structural design of the shield, and demonstrates that it may be possible to use water for a lunar reactor shield.

  6. Shield calculations, optimization vs. paradigm; Calculos de blindajes, optimizacion vs. paradigma

    Energy Technology Data Exchange (ETDEWEB)

    Cornejo D, N.; Hernandez S, A.; Martinez G, A. [Centro de Proteccion e Higiene de las Radiaciones, Calle 20 No. 4113 e/41 y 47 Playa C.P. 11300 LaHabana (Cuba)]. e-mail: nestor@cphr.edu.cu

    2006-07-01

    Many shieldings have been designed under the criteria of 'Maximum dose rates of project'. It has created the paradigm of those 'low dose rates', for the one which not few specialists would consider unacceptable levels of dose rate superior to the units of {mu}Sv.h{sup -1}, independently of the exposure times. At the present time numerous shieldings are being designed considering dose restrictions in real times of exposure. After these new shieldings, the dose rates could be notably superior to those after traditional shieldings, without it implies inadequate designs or constructive errors. In the work significant differences in levels of dose rates and thickness of shieldings estimated by both methods for some typical facilities. It was concluded that the use of real times of exposure is more adequate for the optimization of the Radiological Protection, although this method demands bigger care in its application. (Author)

  7. Peri-conceptional A1C and risk of serious adverse pregnancy outcome in 933 women with type 1 diabetes

    DEFF Research Database (Denmark)

    Jensen, Dorte M; Korsholm, Lars; Ovesen, Per;

    2009-01-01

    OBJECTIVE: To study the association between peri-conceptional A1C and serious adverse pregnancy outcome (congenital malformations and perinatal mortality). RESEARCH DESIGN AND METHODS: Prospective data were collected in 933 singleton pregnancies complicated by type 1 diabetes. RESULTS: The risk...... of serious adverse outcome at different A1C levels was compared with the background population. The risk was significantly higher when peri-conceptional A1C exceeded 6.9%, and the risk tended to increase gradually with increasing A1C. Women with A1C exceeding 10.4% had a very high risk of 16%. Congenital...... malformation rate increased significantly at A1C above 10.4%, whereas perinatal mortality was increased even at A1C below 6.9%. CONCLUSIONS: These results support recent guidelines of preconceptional A1C levels

  8. Manufacturing technique and performance of functionally graded concrete segment in shield tunnel

    Institute of Scientific and Technical Information of China (English)

    Baoguo MA; Dinghua ZOU; Li XU

    2009-01-01

    The quality of segment is very important to theservice life of shield tunnel. Concerning the complex engineering environment of the Wuhan Yangtze River Shield Tunnel, the principle of functionally graded materials was introduced to design and produce the functionally graded concrete segment (FGCS). Its key manufacturing technique was proposed and its perfor-mance was tested.

  9. Testing the integrity of packaging radiation shielding by scanning with radiation source and detector

    International Nuclear Information System (INIS)

    This specification deals with the radiological scanning method of inspection for biological shielding (to be used in transport packaging for gamma emitting sources of radiation), of regular thickness, when the sections are to be checked for integrity and homogeneity; it does not establish the adequacy of design. The shielding materials may be lead, iron, steel, heavy alloy (tungsten), and depleted uranium. (author)

  10. Beam removal block and shielding resign for the MARS neutron therapy reactor

    International Nuclear Information System (INIS)

    The beam removal block and shielding design for the MARS neutron therapy reactor are described. The requirements to the beams' characteristics, filters, collimator and reactor shielding are formulated. Radiation field levels in medical box are analyzed for beams' different operation conditions. It is stated that the removal block and shutter compositions meet necessary conditions in radiation treatment and emergency evacuation

  11. 7 CFR 1c.112 - Review by institution.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Review by institution. 1c.112 Section 1c.112 Agriculture Office of the Secretary of Agriculture PROTECTION OF HUMAN SUBJECTS § 1c.112 Review by institution... review and approval or disapproval by officials of the institution. However, those officials may...

  12. A Novel Radiation Shielding Material Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Radiation shielding simulations showed that epoxy loaded with 10-70% polyethylene would be an excellent shielding material against GCRs and SEPs. Milling produced...

  13. Hydrogen-Induced Cracking of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua

    2004-09-07

    Hydrogen-induced cracking is characterized by the decreased ductility and fracture toughness of a material due to the absorption of atomic hydrogen in the metal crystal lattice. Corrosion is the source of hydrogen generation. For the current design of the engineered barrier without backfill, hydrogen-induced cracking may be a concern because the titanium drip shield can be galvanically coupled to rock bolts (or wire mesh), which may fall onto the drip shield, thereby creating conditions for hydrogen production by electrochemical reaction. The purpose of this report is to analyze whether the drip shield will fail by hydrogen-induced cracking under repository conditions within 10,000 years after emplacement. Hydrogen-induced cracking is a scenario of premature failure of the drip shield. This report develops a realistic model to assess the form of hydrogen-induced cracking degradation of the drip shield under the hydrogen-induced cracking. The scope of this work covers the evaluation of hydrogen absorbed due to general corrosion and galvanic coupling to less noble metals (e.g., Stainless Steel Type 316 and carbon steels) under the repository conditions during the 10,000-year regulatory period after emplacement and whether the absorbed hydrogen content will exceed the critical hydrogen concentration value, above which the hydrogen-induced cracking is assumed to occur. This report also provides the basis for excluding the features, events, and processes (FEPs) related to hydrogen-induced cracking of the drip shield with particular emphasis on FEP 2.1.03.04.OB, hydride cracking of drip shields (DTN: M00407SEPFEPLA.000 [DIRS 170760]). This report is prepared according to ''Technical Work Plan (TWP) for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 169944]).

  14. Hydrogen-Induced Cracking of the Drip Shield

    International Nuclear Information System (INIS)

    Hydrogen-induced cracking is characterized by the decreased ductility and fracture toughness of a material due to the absorption of atomic hydrogen in the metal crystal lattice. Corrosion is the source of hydrogen generation. For the current design of the engineered barrier without backfill, hydrogen-induced cracking may be a concern because the titanium drip shield can be galvanically coupled to rock bolts (or wire mesh), which may fall onto the drip shield, thereby creating conditions for hydrogen production by electrochemical reaction. The purpose of this report is to analyze whether the drip shield will fail by hydrogen-induced cracking under repository conditions within 10,000 years after emplacement. Hydrogen-induced cracking is a scenario of premature failure of the drip shield. This report develops a realistic model to assess the form of hydrogen-induced cracking degradation of the drip shield under the hydrogen-induced cracking. The scope of this work covers the evaluation of hydrogen absorbed due to general corrosion and galvanic coupling to less noble metals (e.g., Stainless Steel Type 316 and carbon steels) under the repository conditions during the 10,000-year regulatory period after emplacement and whether the absorbed hydrogen content will exceed the critical hydrogen concentration value, above which the hydrogen-induced cracking is assumed to occur. This report also provides the basis for excluding the features, events, and processes (FEPs) related to hydrogen-induced cracking of the drip shield with particular emphasis on FEP 2.1.03.04.OB, hydride cracking of drip shields (DTN: M00407SEPFEPLA.000 [DIRS 170760]). This report is prepared according to ''Technical Work Plan (TWP) for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 169944])

  15. Analysis list: JMJD1C [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available JMJD1C Blood + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/JMJD1C.1....tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/JMJD1C.5.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/JM...JD1C.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/JMJD1C.Blood.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/Blood.gml ...

  16. A detector for use in high energy bremsstrahlung shielding studies

    International Nuclear Information System (INIS)

    The design, development and calibration of a detector based on the principle of the Moxon-Rae detector is discussed. It is ideally suited to the measurement of the energy fluence of photons transmitted through a thick shield which has been irradiated with high energy bremsstrahlung. The detection sensitivity is 104 to 105 times that of the P2 ion chamber

  17. Systems for neutronic, thermohydraulic and shielding calculation in personal computers

    International Nuclear Information System (INIS)

    The MTR-PC (Materials Testing Reactors-Personal Computers) system has been developed by the Nuclear Engineering Division of INVAP S.E. with the aim of providing working conditions integrated with personal computers for design and neutronic, thermohydraulic and shielding analysis for reactors employing plate type fuel. (Author)

  18. EFFECTIVE SHIELDING OF UNIDIRECTIONAL CURRENT GENERATED MAGNETIC FIELDS

    Institute of Scientific and Technical Information of China (English)

    徐霖; 傅正财; 杜亚平

    2002-01-01

    This paper presented an effective shielding design of magnetic fields generated by unidirectional current.Theoretical formulas and numerical computation software based on boundary element method (BEM) are employed to evaluate the shielding effectiveness (SE) of cylindrical shell. It is shown that ungrounded or one-end-grounded metal shell is ineffective for such magnetic fields. SE can be obtained by connecting the two ends of the conducting shell with low impedance connector, or alternatively, grounding the two ends. The experimental results also support these conclusions.

  19. Design of software for calculation of shielding based on various standards radiodiagnostic calculation; Diseno de un software para el calculo de blindajes en radiodiagnostico basado en varios estandares de calculo

    Energy Technology Data Exchange (ETDEWEB)

    Falero, B.; Bueno, P.; Chaves, M. A.; Ordiales, J. M.; Villafana, O.; Gonzalez, M. J.

    2013-07-01

    The aim of this study was to develop a software application that performs calculation shields in radiology room depending on the type of equipment. The calculation will be done by selecting the user, the method proposed in the Guide 5.11, the Report 144 and 147 and also for the methodology given by the Portuguese Health Ministry. (Author)

  20. Novel shielding materials for space and air travel

    International Nuclear Information System (INIS)

    The reduction of dose onboard spacecraft and aircraft by appropriate shielding measures plays an essential role in the future development of space exploration and air travel. The design of novel shielding strategies and materials may involve hydrogenous composites, as it is well known that liquid hydrogen is most effective in attenuating charged particle radiation. As precursor for a later flight experiment, the shielding properties of newly developed hydrogen-rich polymers and rare earth-doped high-density rubber were tested in various ground-based neutron and heavy ion fields and compared with aluminium and polyethylene as reference materials. Absorbed dose, average linear energy transfer and gamma-equivalent neutron absorbed dose were determined by means of LiF:Mg,Ti thermoluminescence dosemeters and CR-39 plastic nuclear track detectors. First results for samples of equal aerial density indicate that selected hydrogen-rich plastics and rare-earth-doped rubber may be more effective in attenuating cosmic rays by up to 10% compared with conventional aluminium shielding. The appropriate adaptation of shielding thicknesses may thus allow reducing the biologically relevant dose. Owing to the lower density of the plastic composites, mass savings shall result in a significant reduction of launch costs. The experiment was flown as part of the European Space Agency's Biopan-5 mission in May 2005. (authors)

  1. Shielding measurements for a 230 MeV proton beam

    International Nuclear Information System (INIS)

    Energetic secondary neutrons produced as protons interact with accelerator components and patients dominate the radiation shielding environment for proton radiotherapy facilities. Due to the scarcity of data describing neutron production, attenuation, absorbed dose, and dose equivalent values, these parameters were measured for 230 MeV proton bombardment of stopping length Al, Fe, and Pb targets at emission angles of 0 degree, 22 degree, 45 degree, and 90 degree in a thick concrete shield. Low pressure tissue-equivalent proportional counters with volumes ranging from 1 cm3 to 1000 cm3 were used to obtain microdosimetric spectra from which absorbed dose and radiation quality are deduced. Does equivalent values and attenuation lengths determined at depth in the shield were found to vary sharply with angle, but were found to be independent of target material. Neutron dose and radiation length values are compared with Monte Carlo neutron transport calculations performed using the Los Alamos High Energy Transport Code (LAHET). Calculations used 230 MeV protons incident upon an Fe target in a shielding geometry similar to that used in the experiment. LAHET calculations overestimated measured attenuation values at 0 degree, 22 degree, and 45 degree, yet correctly predicted the attenuation length at 90 degree. Comparison of the mean radiation quality estimated with the Monte Carlo calculations with measurements suggest that neutron quality factors should be increased by a factor of 1.4. These results are useful for the shielding design of new facilities as well as for testing neutron production and transport calculations

  2. Magnetic Shielding Studies of the RICH Photon Detectors

    CERN Document Server

    Patel, M; Gys, Thierry

    2006-01-01

    The Hybrid Photon Detectors (HPDs) adopted for LHCb's RICH detectors are required to operate in the fringe field of the 4Tm LHCb dipole magnet. In fields in excess of 15G, photoelectrons are lost from the active area of an HPD. Shielding the HPDs from the fringe field is therefore essential for the efficient operation of the RICH detectors. A primary magnetic shield has been designed that reduces the field at the photon detectors to <20G. This field is to be further reduced by a set of individual secondary magnetic shields around each HPD. This note describes the technique used to calculate the residual field inside these secondary shields. The size of the problem, together with the disparity in the geometric scales involved, make the calculations intractable using a finite element model of the entire magnetic environment. As a result, a sub-modelling method has been used together with a rectangular approximation to the circular cross-section shields. The model indicates that with a 89.5mm HPD pitch, 0.9mm...

  3. A Ballistic Limit Analysis Program for Shielding Against Micrometeoroids and Orbital Debris

    Science.gov (United States)

    Ryan, Shannon; Christiansen, Erie

    2010-01-01

    A software program has been developed that enables the user to quickly and simply perform ballistic limit calculations for common spacecraft structures that are subject to hypervelocity impact of micrometeoroid and orbital debris (MMOD) projectiles. This analysis program consists of two core modules: design, and; performance. The design module enables a user to calculate preliminary dimensions of a shield configuration (e.g., thicknesses/areal densities, spacing, etc.) for a ?design? particle (diameter, density, impact velocity, incidence). The performance module enables a more detailed shielding analysis, providing the performance of a user-defined shielding configuration over the range of relevant in-orbit impact conditions.

  4. Electrodynamic Dust Shield for Space Applications

    Science.gov (United States)

    Mackey, Paul J.; Johansen, Michael R.; Olsen, Robert C.; Raines, Matthew G.; Phillips, James R., III; Cox, Rachel E.; Hogue, Michael D.; Calle, Carlos I.; Pollard, Jacob R. S.

    2016-01-01

    The International Space Exploration Coordination Group (ISECG) has chosen dust mitigation technology as a Global Exploration Roadmap (GER) critical technology need in order to reduce life cycle cost and risk, and increase the probability of mission success. NASA has also included Particulate Contamination Prevention and Mitigation as a cross-cutting technology to be developed for contamination prevention, cleaning and protection. This technology has been highlighted due to the detrimental effect of dust on both human and robotic missions. During manned Apollo missions, dust caused issues with both equipment and crew. Contamination of equipment caused many issues including incorrect instrument readings and increased temperatures due to masking of thermal radiators. The astronauts were directly affected by dust that covered space suits, obscured face shields and later propagated to the cabin and into the crew's eyes and lungs. Robotic missions on Mars were affected when solar panels were obscured by dust thereby reducing the effectiveness of the solar panels. The Electrostatics and Surface Physics Lab in Swamp Works at the Kennedy Space Center has been developing an Electrodynamic Dust Shield (EDS) to remove dust from multiple surfaces, including glass shields and thermal radiators. This technology has been tested in lab environments and has evolved over several years. Tests of the technology include reduced gravity flights (6g) in which Apollo Lunar dust samples were successfully removed from glass shields while under vacuum (1 millipascal). Further development of the technology is underway to reduce the size of the EDS as well as to perform material and component testing outside of the International Space Station (ISS) on the Materials on International Space Station Experiment X (MISSE-X). This experiment is designed to verify that the EDS can withstand the harsh environment of space and will look to closely replicate the solar environment experienced on the moon

  5. Critical Dimensionless Shields Values for Bankfull Flow

    Science.gov (United States)

    Bunte, K.; Abt, S. R.; Swingle, K. W.

    2009-12-01

    The critical dimensionless shear stress τ*c (depicted in the Shields curve as a function of the Reynolds particle number Rep) quantifies the slope - flow depth product at which particles from a relatively well-sorted bed with a mean particle size Dm visually start to move. Contrary to many applications of the Shields curve, τ*c was not designed to predict the bed particle size becoming mobile at bankfull flow. This study sketches a bankfull and a critical bankfull Shields-type curve needed to predict the bankfull mobile particle size. Most studies on bedmaterial entrainment are performed in streams that are wadeable at low flow, but exceed wadeability around bankfull flow. Within the bounds of these stream dimensions, the study drafts a relationship of τ*bf versus Rep (bankfull Shields curve) for a sequence of stream types (in sensu Montgomery and Buffington 1997) ranging from steep cobble headwater streams to plane-bed and pool-riffle gravel-beds to low gradient valley streams with sand and silt beds. Probable values of stream gradient, bed D50 size, and a (roughness corrected) hydraulic radius can be assigned to each stream type. The resulting bankfull curve takes values of τ*bf near 10 for silt and 1 for sand-bedded streams, drops to around 0.05 - 0.02 for mobile gravel-bed streams and then increases towards 0.1 and 0.2 for the steepest streams. Transforming τ*bf into the critical bankfull curve τ*cbf from which to predict the bankfull entrainable particle size requires information on the bedload particle size that becomes mobile at bankfull flow. To estimate τ*cbf over a variety of coarse gravel- and cobble-bed mountain streams, the authors used flow competence curves measured with bedload traps at 10 sites. Bedload traps have a 0.3 m by 0.2 m opening, and 1-1.6 m long trailing net with a 4 mm mesh; mounting traps onto ground plates anchored to the stream bottom permits 1-hr sampling times; 4 to 6 traps are typically installed across the stream width

  6. A new radiation shielding material: Amethyst ore

    Energy Technology Data Exchange (ETDEWEB)

    Korkut, Turgay, E-mail: turgaykorkut@hotmail.co [Faculty of Science and Art, Department of Physics, Ibrahim Cecen University, Agri (Turkey); Korkut, Hatun [Faculty of Science and Art, Department of Physics, Ibrahim Cecen University, Agri (Turkey); Karabulut, Abdulhalik; Budak, Goekhan [Faculty of Science, Department of Physics, Atatuerk University, Erzurum (Turkey)

    2011-01-15

    This paper describes a new radiation shielding material, amethyst ore. We have determined the elemental composition of amethyst using WDXRF spectroscopy technique. To see the shielding capability of amethyst for several photon energies, these results have been used in simulation process by FLUKA Monte Carlo radiation transport code. Linear attenuation coefficients have been calculated according to the simulation results. Then, these values have been compared to a fine shielding concrete material. The results show that amethyst shields more gamma beams than concrete. This investigation is the first study about the radiation shielding properties of amethyst ore.

  7. DECOVALEX ll PROJECT. Technical Report Task 1C

    Energy Technology Data Exchange (ETDEWEB)

    Jing, L.; Stephansson, O. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Civil and Environmental Engineering; Knight, L.J. [United Kingdom Nirex Ltd., Harwell (United Kingdom); Kautsky, F. [Swedish Nuclear Power Inspectorate, Stockholm (Sweden); Tsang, C-F. [Lawrence Berkeley National Lab., Berkeley, CA (United States). Earth Science Division

    1999-05-01

    due to shaft excavation and a reinforcement study, which made the task relevant to issues of constructability and repository design. Presented in this report are the definition, conceptual models, comparison and analysis of the numerical results and concluding remarks of Task 1C. There were six research teams who participated in this task with different conceptual models and numerical models.

  8. Concrete enclosure to shield a neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Villagrana M, L. E.; Rivera P, E.; De Leon M, H. A.; Soto B, T. G.; Hernandez D, V. M.; Vega C, H. R., E-mail: emmanuelvillagrana@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Apdo. Postal 336, 98000 Zacatecas (Mexico)

    2012-10-15

    In the aim to design a shielding for a {sup 239}PuBe isotopic neutron source several Monte Carlo calculations were carried out using MCNP5 code. First, a point-like source was modeled in vacuum and the neutron spectrum and the ambient dose equivalent were calculated at several distances ranging from 5 up to 150 cm, these calculations were repeated including air, and a 1 x 1 x 1 m{sup 3} enclosure that was shielded with 5, 15, 20, 25, 30, 50 and 80 cm-thick Portland type concrete walls. At all the points located inside the enclosure neutron spectra from 10{sup -8} up 0.5 MeV were the same regardless the distance from the source showing the room-return effect, for energies larger than 0.5 MeV neutron spectra are diminished as the distance increases. Outside the enclosure it was noticed that neutron spectra becomes -softer- as the concrete thickness increases due to reduction of mean neutron energy. With the ambient dose values the attenuation curve in terms of concrete thickness was calculated. (Author)

  9. Discussion on variance reduction technique for shielding

    Energy Technology Data Exchange (ETDEWEB)

    Maekawa, Fujio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    As the task of the engineering design activity of the international thermonuclear fusion experimental reactor (ITER), on 316 type stainless steel (SS316) and the compound system of SS316 and water, the shielding experiment using the D-T neutron source of FNS in Japan Atomic Energy Research Institute has been carried out. However, in these analyses, enormous working time and computing time were required for determining the Weight Window parameter. Limitation or complication was felt when the variance reduction by Weight Window method of MCNP code was carried out. For the purpose of avoiding this difficulty, investigation was performed on the effectiveness of the variance reduction by cell importance method. The conditions of calculation in all cases are shown. As the results, the distribution of fractional standard deviation (FSD) related to neutrons and gamma-ray flux in the direction of shield depth is reported. There is the optimal importance change, and when importance was increased at the same rate as that of the attenuation of neutron or gamma-ray flux, the optimal variance reduction can be done. (K.I.)

  10. Large scale mechanical metamaterials as seismic shields

    Science.gov (United States)

    Miniaci, Marco; Krushynska, Anastasiia; Bosia, Federico; Pugno, Nicola M.

    2016-08-01

    Earthquakes represent one of the most catastrophic natural events affecting mankind. At present, a universally accepted risk mitigation strategy for seismic events remains to be proposed. Most approaches are based on vibration isolation of structures rather than on the remote shielding of incoming waves. In this work, we propose a novel approach to the problem and discuss the feasibility of a passive isolation strategy for seismic waves based on large-scale mechanical metamaterials, including for the first time numerical analysis of both surface and guided waves, soil dissipation effects, and adopting a full 3D simulations. The study focuses on realistic structures that can be effective in frequency ranges of interest for seismic waves, and optimal design criteria are provided, exploring different metamaterial configurations, combining phononic crystals and locally resonant structures and different ranges of mechanical properties. Dispersion analysis and full-scale 3D transient wave transmission simulations are carried out on finite size systems to assess the seismic wave amplitude attenuation in realistic conditions. Results reveal that both surface and bulk seismic waves can be considerably attenuated, making this strategy viable for the protection of civil structures against seismic risk. The proposed remote shielding approach could open up new perspectives in the field of seismology and in related areas of low-frequency vibration damping or blast protection.

  11. Shielding calculational system for plutonium

    International Nuclear Information System (INIS)

    A computer calculational system has been developed and assembled specifically for calculating dose rates in AEC plutonium fabrication facilities. The system consists of two computer codes and all nuclear data necessary for calculation of neutron and gamma dose rates from plutonium. The codes include the multigroup version of the Battelle Monte Carlo code for solution of general neutron and gamma shielding problems and the PUSHLD code for solution of shielding problems where low energy gamma and x-rays are important. The nuclear data consists of built in neutron and gamma yields and spectra for various plutonium compounds, an automatic calculation of age effects and all cross-sections commonly used. Experimental correlations have been performed to verify portions of the calculational system. (23 tables, 7 figs, 16 refs) (U.S.)

  12. Stellar activity and magnetic shielding

    CERN Document Server

    Grießmeier, J -M; Lammer, H; Grenfell, J L; Stadelmann, A; Motschmann, U; 10.1017/S1743921309992961

    2010-01-01

    Stellar activity has a particularly strong influence on planets at small orbital distances, such as close-in exoplanets. For such planets, we present two extreme cases of stellar variability, namely stellar coronal mass ejections and stellar wind, which both result in the planetary environment being variable on a timescale of billions of years. For both cases, direct interaction of the streaming plasma with the planetary atmosphere would entail servere consequences. In certain cases, however, the planetary atmosphere can be effectively shielded by a strong planetary magnetic field. The efficiency of this shielding is determined by the planetary magnetic dipole moment, which is difficult to constrain by either models or observations. We present different factors which influence the strength of the planetary magnetic dipole moment. Implications are discussed, including nonthermal atmospheric loss, atmospheric biomarkers, and planetary habitability.

  13. Paramagnetism shielding in drilling fluid

    OpenAIRE

    Li, Zhuo

    2013-01-01

    In drilling operations, drilling fluid containing magnetic materials is used when drilling a well. The materials can significantly shield the Earth’s magnetic field as measured by magnetic sensors inside the drilling strings. The magnetic property of the drilling fluid is one of the substantial error sources for the determination of magnetic azimuth for wellbores. Both the weight material, cuttings, clay and other formation material plus metal filings from the tubular wear m...

  14. Water shielding nuclear reactor container

    International Nuclear Information System (INIS)

    The reactor container of the present invention contains a reactor pressure vessel, and has double steel plate walls endurable to elevated inner pressure and keeping airtightness, and shielding water is filled inside from a water injection port. It is endurable to a great inner pressure satisfactorily and keep airtightness by the two spaced relatively thin steel plates. It exhibits radiation shielding effect by filling water substantially the same as that of a conventional reactor container made of iron reinforced concretes. Then, it is no more necessary to use concretes for the construction of the reactor container, which shortens the term of the construction, and saves the construction cost. In addition, a cooling effect for the reactor container is provided. Syphons are disposed contiguously to a water injection port and the top end of the syphon is immersed in an equipment temporarily storage pool, and further, pipelines are connected to the double steel plate walls or the syphons for supplying shielding water to enhance the cooling effect. (N.H.)

  15. RF-transparent solar shield

    International Nuclear Information System (INIS)

    By combining durable Kapton films with quartz fibers, an effective solar shield or blanket is produced which also serves as an efficient RF-transparent window. The window consists of a series of Kapton film envelopes sandwiching thin quartz paper. Not only must the window prevent the sun from overheating the electronics and distorting mechanically aligned antennas, it must also prevent radiant heat loss from inside the satellite when it is in shadow and radiating to space at approx. 40K. The guidelines for achieving an effective high-frequency RF window are a low dielectric constant to keep reflections down, a low loss tangent so RF absorption and molecular movement will be minimal, and low mass with tin and lightweight materials. Because these guidelines were followed, the RF insertion loss of the multiple envelope shield is less than 1/4 dB at high frequency. This paper concentrates on the material and processing aspects of an RF-transparent solar shield

  16. Drugs affecting HbA1c levels

    Directory of Open Access Journals (Sweden)

    Ranjit Unnikrishnan

    2012-01-01

    Full Text Available Glycated hemoglobin (HbA1c is an important indicator of glycemic control in diabetes mellitus, based on which important diagnostic and therapeutic decisions are routinely made. However, there are several situations in which the level of HbA1c may not faithfully reflect the glycemic control in a given patient. Important among these is the use of certain non-diabetic medications, which can affect the HbA1c levels in different ways. This review focuses on the non-diabetic medications which can inappropriately raise or lower the HbA1c levels, and the postulated mechanisms for the same.

  17. Attenuation curves in concrete of neutrons from 1 GeV/u C and U ions on a Fe target for the shielding design of RIB in-flight facilities

    CERN Document Server

    Agosteo, S; Silari, M

    2004-01-01

    Experimental data on neutron emission from the interaction of heavy ion beams with matter are far less abundant than data on neutron production from protons. The aim of the present work is to extend the available computational shielding data to high-energy neutrons produced by heavy ion beams (uranium and carbon) of 1 GeV/u slowed down in a thick iron target. Source terms and attenuation lengths for neutron attenuation in a concrete shield were calculated starting from experimental neutron energy distributions measured at GSI in the angular range from 0 degree to 90 degree . A comparison is also made with previous calculations performed for different ions and energies and with earlier estimates made at GSI for neon beams with 0.8 and 2 GeV/u energy stopped in thick iron, lead and uranium targets.

  18. Strength analysis results for the RF 'modified' option of the shielding block for ITER blanket module

    International Nuclear Information System (INIS)

    In accordance with the combined analysis of 'reference' shield block (SB) design option the RF specialist have adopted the decision to develop the 'modified' one. The present article contains the results of strength analysis for 'modified' shield block design developed by the RF Domestic Agency. This stage of analysis is devoted to strength analysis of 'lid-SB'-welded joint for elastic and elasto-plastic approach. There two welding types have been considered: electron beam welding (EB-welding) and thermal welding in inert gas (TIG-welding). These results together with the technological R and D will be useful for final decision on the shield block manufacturing technology.

  19. Shielding calculations using computer techniques; Calculo de blindajes mediante tecnicas de computacion

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Portilla, M. I.; Marquez, J.

    2011-07-01

    Radiological protection aims to limit the ionizing radiation received by people and equipment, which in numerous occasions requires of protection shields. Although, for certain configurations, there are analytical formulas, to characterize these shields, the design setup may be very intensive in numerical calculations, therefore the most efficient from to design the shields is by means of computer programs to calculate dose and dose rates. In the present article we review the codes most frequently used to perform these calculations, and the techniques used by such codes. (Author) 13 refs.

  20. Dynamic Open-Rotor Composite Shield Impact Test Report

    Science.gov (United States)

    Seng, Silvia; Frankenberger, Charles; Ruggeri, Charles R.; Revilock, Duane M.; Pereira, J. Michael; Carney, Kelly S.; Emmerling, William C.

    2015-01-01

    The Federal Aviation Administration (FAA) is working with the European Aviation Safety Agency to determine the certification base for proposed new engines that would not have a containment structure on large commercial aircraft. Equivalent safety to the current fleet is desired by the regulators, which means that loss of a single fan blade will not cause hazard to the aircraft. NASA Glenn and Naval Air Warfare Center (NAWC) China Lake collaborated with the FAA Aircraft Catastrophic Failure Prevention Program to design and test a shield that would protect the aircraft passengers and critical systems from a released blade that could impact the fuselage. This report documents the live-fire test from a full-scale rig at NAWC China Lake. NASA provided manpower and photogrammetry expertise to document the impact and damage to the shields. The test was successful: the blade was stopped from penetrating the shield, which validates the design analysis method and the parameters used in the analysis. Additional work is required to implement the shielding into the aircraft.

  1. Micrometeoroid and Orbital Debris (MMOD) Shield Ballistic Limit Analysis Program

    Science.gov (United States)

    Ryan, Shannon

    2013-01-01

    This software implements penetration limit equations for common micrometeoroid and orbital debris (MMOD) shield configurations, windows, and thermal protection systems. Allowable MMOD risk is formulated in terms of the probability of penetration (PNP) of the spacecraft pressure hull. For calculating the risk, spacecraft geometry models, mission profiles, debris environment models, and penetration limit equations for installed shielding configurations are required. Risk assessment software such as NASA's BUMPERII is used to calculate mission PNP; however, they are unsuitable for use in shield design and preliminary analysis studies. The software defines a single equation for the design and performance evaluation of common MMOD shielding configurations, windows, and thermal protection systems, along with a description of their validity range and guidelines for their application. Recommendations are based on preliminary reviews of fundamental assumptions, and accuracy in predicting experimental impact test results. The software is programmed in Visual Basic for Applications for installation as a simple add-in for Microsoft Excel. The user is directed to a graphical user interface (GUI) that requires user inputs and provides solutions directly in Microsoft Excel workbooks.

  2. EMI Shields made from intercalated graphite composites

    Science.gov (United States)

    Gaier, James R.; Terry, Jennifer

    1995-01-01

    Electromagnetic interference (EMI) shielding typically makes up about twenty percent of the mass of a spacecraft power system. Graphite fiber/polymer composites have significantly lower densities and higher strengths than aluminum, the present material of choice for EMI shields, but they lack the electrical conductivity that enables acceptable shielding effectiveness. Bromine intercalated pitch-based graphite/epoxy composites have conductivities fifty times higher than conventional structural graphite fibers. Calculations are presented which indicate that EMI shields made from such composites can have sufficient shielding at less than 20% of the mass of conventional aluminum shields. EMI shields provide many functions other than EMI shielding including physical protection, thermal management, and shielding from ionizing radiation. Intercalated graphite composites perform well in these areas also. Mechanically, they have much higher specific strength and modulus than aluminum. They also have shorter half thicknesses for x-rays and gamma radiation than aluminum. Thermally, they distribute infra-red radiation by absorbing and re-radiating it rather than concentrating it by reflection as aluminum does. The prospects for intercalated graphite fiber/polymer composites for EMI shielding are encouraging.

  3. Thes - Website for Thermal Shields Upgrade Management

    CERN Document Server

    Micula, Adina

    2013-01-01

    There are a total of 1695 thermal shields (TS) in the interconnections between the superconducting magnets. During LHC Long Shutdown 1 (LS1) all of these TS are being upgraded with a new fixation design. This procedure involves the transport of all the TS from LHC to a workshop on the surface where they are being modified and the subsequent transport of the upgraded TS back to the tunnel where they are laid on the cryostats and await the closure of the interconnection. These operations have to be carefully coordinated in order to ensure that there are always enough modified TS to satisfy the demand in the tunnel and respect the time constraint imposed by the schedule of LS1. As part of my summer project, I developed a database driven website whose aim is to enable the TS upgrade monitoring.

  4. Large Magnetic Shielding Factor Measured by Nonlinear Magneto-optical Rotation

    CERN Document Server

    Martin, Jeffery W; Klassen, Wolfgang; Cerasani, Cameron; Andalib, Taraneh; Bidinosti, Christopher P; Lang, Michael; Ostapchuk, David

    2014-01-01

    A passive magnetic shield was designed and constructed for magnetometer tests for the future neutron electric dipole moment experiment at TRIUMF. The axial shielding factor of the magnetic shield was measured using a magnetometer based on non-linear magneto-optical rotation of the plane of polarized laser light upon passage through a paraffin-coated vapour cell containing natural Rb at room temperature. The laser was tuned to the Rb D1 line, near the $^{85}$Rb $F=2\\rightarrow 2,3$ transition. The shielding factor was measured by applying an axial field externally and measuring the magnetic field internally using the magnetometer. The axial shielding factor was determined to be $(1.3\\pm 0.1)\\times 10^{7}$, from an applied axial field of 1.45~$\\mu$T in the background of Earth's magnetic field.

  5. Simple technique for fabrication of shielding blocks for total body irradiation at extended treatment distances

    Directory of Open Access Journals (Sweden)

    Ravichandran R

    2009-01-01

    Full Text Available Techniques are being standardized in our department for total body irradiation (TBI with six MV photons in linear accelerator for preconditioning to bone marrow transplantation (BMT. Individualized shields with low melting point alloy are to be fabricated for shielding critical organs such as lungs, kidneys etc. A method to mount diminished dimension of shields in a tray at 3.75m is designed in the department for a teletreatment distance of four meters with magna field with A simulator image taken with the patient′s midplane (MP at one meter distance is used to mark the dimensions of lung, scaled down by a factor of 3.75/4.0. These lung dimensions are reprinted from the digital simulator image for making the shield. The methodology of the technique using digitized minification in radiography is the first of its kind to be used for shield cutting in magna field radiotherapy.

  6. 超高速撞击Kevlar纤维布填充防护结构研究%Optimal Structural Design of Stuffed Shields with Kevlar Fiber Clothes against Hypervelocity Impact

    Institute of Scientific and Technical Information of China (English)

    张宝玺; 哈跃; 邓云飞; 庞宝君

    2013-01-01

    A series of impact experiments are conducted to investigate the ballistic performances of stuffed Whipple shields with Kevlar fiber clothes using a two-stage light gas gun facilities. Based on the impact limit curve of Nextel/Kevlar stuffed Whipple shields,the protective performances of Kevlar stuffed Whipple shields,the damage morphology and mechanism of stuffed material and bulkhead are obtained and compared. The main results show as following: the stuffed Whipple shields with Kevlar fiber clothes have excellent protection performance at the low impact velocity;the double-layer packing structure can improve the protective performance. Kevlar fibers sufficiently absorb energy by plastic deformation and fracture when the impact velocity is low. In addition, high temperature melting and carbonization phenomenon appear in the hypervelocity region, which help break up and melt the projectiles that minimize the damage to cabin wall. This exploratory method provides us a useful way to make the ballistic performances of stuffed Whipple shields more perfect in space debris protection field.%利用二级轻气炮,对Kevlar纤维布填充Whipple防护结构进行了超高速撞击实验研究.基于Nextel/Kevlar撞击极限曲线,分析了单层及双层Kevlar纤维布填充防护结构的防护性能以及填充材料、舱壁的损伤情况.实验表明,Kevlar纤维布填充Whipple防护结构在低速区具有优良的防护性能.分层布局可改善Kevlar纤维布填充Whipple防护结构在低速区的防护性能.在低速区,Kevlar纤维丝主要依靠大量的塑性变形及断裂吸收弹丸的动能;在高速区,Kevlar纤维丝存在高温熔化及碳化现象,使弹丸破碎或熔化为更小的碎片或熔球,从而减轻对舱壁的损伤.

  7. Haemoglobin A1c : Historical overview and current concepts

    NARCIS (Netherlands)

    Lenters-Westra, Erna; Schindhelm, Roger K.; Bilo, Henk J.; Slingerland, Robbert J.

    2013-01-01

    Since the discovery of the relation between increased concentrations of fast haemoglobin fractions in patients with diabetes mellitus compared to concentrations in subjects without diabetes mellitus by Samuel Rahbar and co-workers in 1969, glycated haemoglobin A1c (HbA1c) has become a "gold standard

  8. Thermal, Radiation and Impact Protective Shields (TRIPS) for Robotic and Human Space Exploration Missions

    Science.gov (United States)

    Loomis, M. P.; Arnold, J. L.

    2005-01-01

    New concepts for protective shields for NASA s Crew Exploration Vehicles (CEVs) and planetary probes offer improved mission safety and affordability. Hazards include radiation from cosmic rays and solar particle events, hypervelocity impacts from orbital debris/ micrometeorites, and the extreme heating environment experienced during entry into planetary atmospheres. The traditional approach for the design of protection systems for these hazards has been to create single-function shields, i.e. ablative and blanket-based heat shields for thermal protection systems (TPS), polymer or other low-molecular-weight materials for radiation shields, and multilayer, Whipple-type shields for protection from hypervelocity impacts. This paper introduces an approach for the development of a single, multifunctional protective shield, employing nanotechnology- based materials, to serve simultaneously as a TPS, an impact shield and as the first line of defense against radiation. The approach is first to choose low molecular weight ablative TPS materials, (existing and planned for development) and add functionalized carbon nanotubes. Together they provide both thermal and radiation (TR) shielding. Next, impact protection (IP) is furnished through a tough skin, consisting of hard, ceramic outer layers (to fracture the impactor) and sublayers of tough, nanostructured fabrics to contain the debris cloud from the impactor before it can penetrate the spacecraft s interior.

  9. Highly heat-removing radiation shielding material

    International Nuclear Information System (INIS)

    Highly heat-removing radiation shielding material is constituted with fine particles prepared by coating metals of high heat conductivity to fine particles comprising materials having excellent radiation shielding performance. Then, the fine particles applied with the coating are mixed and filled in a shielding container or applied with hot press into a layerous form and used as a shielding member. In view of the above, since the coated fine particles provide the shielding performance against radiation such as neutrons and gamma rays, and the coating metals provide the heat removing performance, they act as a shielding material having heat removing performance as a whole. The combination of the coated fine particles and the coating metals are selected depending on the respective conditions for use. With such a constitution, radioactive wastes involving a problem of heat generation can be transported or stored safely. (T.M.)

  10. VAPOR SHIELD FOR INDUCTION FURNACE

    Science.gov (United States)

    Reese, S.L.; Samoriga, S.A.

    1958-03-11

    This patent relates to a water-cooled vapor shield for an inductlon furnace that will condense metallic vapors arising from the crucible and thus prevent their condensation on or near the induction coils, thereby eliminating possible corrosion or shorting out of the coils. This is accomplished by placing, about the top, of the crucible a disk, apron, and cooling jacket that separates the area of the coils from the interior of the cruclbIe and provides a cooled surface upon whlch the vapors may condense.

  11. Radiation shielding concrete made of Basalt aggregates.

    Science.gov (United States)

    Alhajali, S; Yousef, S; Kanbour, M; Naoum, B

    2013-04-01

    In spite of the fact that Basalt is a widespread type of rock, there is very little available information on using it as aggregates for concrete radiation shielding. This paper investigates the possibility of using Basalt for the aforementioned purpose. The results have shown that Basalt could be used successfully for preparing radiation shielding concrete, but some attention should be paid to the choice of the suitable types of Basalt and for the neutron activation problem that could arise in the concrete shield.

  12. Optimization of NTP System Truss to Reduce Radiation Shield Mass

    Science.gov (United States)

    Scharber, Luke L.; Kharofa, Adam; Caffrey, Jarvis A.

    2016-01-01

    The benefits of nuclear thermal propulsion are numerous and relevant to the current NASA mission goals involving but not limited to the crewed missions to mars and the moon. They do however also present new and unique challenges to the design and logistics of launching/operating spacecraft. One of these challenges, relevant to this discussion, is the significant mass of the shielding which is required to ensure an acceptable radiation environment for the spacecraft and crew. Efforts to reduce shielding mass are difficult to accomplish from material and geometric design points of the shield itself, however by increasing the distance between the nuclear engines and the main body of the spacecraft the required mass of the shielding is lessened considerably. The mass can be reduced significantly per unit length, though any additional mass added by the structure to create this distance serves to offset those savings, thus the design of a lightweight structure is ideal. The challenges of designing the truss are bounded by several limiting factors including; the loading conditions, the capabilities of the launch vehicle, and achieving the ideal truss length when factoring for the overall mass reduced. Determining the overall set of mass values for a truss of varying length is difficult since to maintain an optimally designed truss the geometry of the truss or its members must change. Thus the relation between truss mass and length for these loading scenarios is not linear, and instead has relation determined by the truss design. In order to establish a mass versus length trend for various truss designs to compare with the mass saved from the shield versus length, optimization software was used to find optimal geometric properties that still met the design requirements at established lengths. By solving for optimal designs at various lengths, mass trends could be determined. The initial design findings show a clear benefit to extending the engines as far from the main

  13. Combined Acquisition and Tracking Methods for GPS L1 C/A and L1C Signals

    Directory of Open Access Journals (Sweden)

    Florence Macchi-Gernot

    2010-01-01

    Full Text Available As part of the GPS modernization, the GPS L1 C/A signal will be augmented by the L1C signal. With this improvement, for the first time, several signals from the same constellation will be available at the same frequency. In this paper, an acquisition method is implemented to combine the GPS L1 C/A and L1C signals before correlation. The combined acquisition succeeds to acquire the signal at low C/N0, whereas the acquisition of the L1C data channel alone fails. Concerning the tracking, a method to combine the GPS L1 C/A and L1C signals before the discriminator is developed. This method shows better performance than the traditional tracking using only one signal. Finally, a Kalman filter to combine the signals in the tracking is developed. It shows better performance than the traditional tracking in all conditions. Since the L1C signal will not be broadcast before 2013, these methods are tested using a software signal simulator.

  14. Shielding for thermoacoustic tomography with RF excitation

    Science.gov (United States)

    Mitchell, M.; Becker, G.; Dey, P.; Generotzky, J.; Patch, S. K.

    2008-02-01

    Radiofrequency (RF) pulses used to generate thermoacoustic computerized tomography (TCT) signal couple directly into the pulser-receiver and oscilloscope, swamping true TCT signal. We use a standard RF enclosure housing both RF amplifier and object being imaged. This is similar to RF shielding of magnetic resonance imaging (MRI) suites and protects electronics outside from stray RF. Unlike MRI, TCT receivers are ultrasound transducers, which must also be shielded from RF. A transducer housing that simultaneously shields RF and permits acoustic transmission was developed specifically for TCT. We compare TCT signals measured with and without RF shielding.

  15. SHIELD: Distance Estimates from Hubble Space Telescope Imaging

    Science.gov (United States)

    Cave, Ian; Cannon, J. M.; Larson, E.; Marshall, M.; Moody, S.; Adams, E. A.; Dolphin, A. E.; Elson, E. C.; Giovanelli, R.; Haynes, M. P.; McQuinn, K. B.; Ott, J.; Saintonge, A.; Salzer, J. J.; Skillman, E. D.

    2013-01-01

    The Survey of HI in Extremely Low-mass Dwarfs (SHIELD) is an ongoing study of twelve galaxies with HI masses between 106 and 107 Solar masses, detected by the Arecibo Legacy Fast ALFA (ALFALFA) survey. Here we present new Hubble Space Telescope (HST) imaging of the SHIELD galaxies. The primary goal is to determine the distance of each galaxy. We apply two techniques to measure the apparent magnitude of the tip of the red giant branch (TRGB) feature in the HST color magnitude diagrams. First, a custom designed edge detection filter was written to determine the TRGB magnitude based on a user-selected region of the color magnitude diagram. Second, we apply the maximum likelihood technique implemented in the "TRGBtool" software package (Makarov et al. 2006). In addition to the distances based on the TRGB feature, we also use the MATCH software (Dolphin 2002) to determine the best-fit distance based on the overall CMD morphology. We compare these distance estimates for all members of the SHIELD galaxies, and present a final table of distances that is used in each of the companion SHIELD presentations.

  16. Shielding Desing for Storage of Radioactive Waste from TRR-1/M1 Pool Refurbishment

    International Nuclear Information System (INIS)

    Four sets of bolts and nuts were discarded as radioactive waste from the Thailand Research Reactor TRR-1/M1 pool during the pool refurbishment in 2011. The exposure rate of the waste is roughly 10 R/hr at the contact point and mainly comes from Co-60. The waste is currently stored at the Radioactive Waste Management facility in a generic shield container. This work has been initiated to obtain an optimum design for the shield container which should require less space with lower cost in order to store this waste long-term. The Monte Carlo technique using MCNPX computer program was adopted for the design work.In the first part of the work, the use of MCNPX for the shielding calculation was validated. A simple shielding experiment setup was performed using aluminum, stainless steel and lead as the shield. The experiment used Co-60 as the standard source and used NaI detector with gamma spectrometer for the counting system. The Co-60 attenuation coefficients of these materials were obtained from experiment and MCNPX calculation. Both results were compared and found to be in a very good agreement (the differences wereessentially less than 5%). The conclusion from this comparison was that the use of MCNPX for shielding calculation could provide quite accurate results. In the second part of the work, the preliminary design of new shield container was performed. Lead and stainless steel were both chosen as the materials for the container because they have good shielding properties. The shield container was to have two layers consisting of stainless steel and lead. Using both materials in the shield was foreseen to yield a good compromisebetween space utilization and cost. Moreover, it is preferable that stainless steel be the material in contact with the waste. This is because the waste is made of stainless steel and hence there should be no induced corrosion from material incompatibility. The design approachwas to vary the shield thickness in step in order to optimize the

  17. Thermo-mechanical analysis of the thermal shield for ITER magnet feeder

    International Nuclear Information System (INIS)

    Highlights: • We model the reasonable finite element model for feeder thermal shield. • We analyze the temperature distribution and pressure drop of the thermal shield. • Different materials for the thermal shield were analyzed. • Thermal stress analysis was performed and analysis result be applied to the detailed design. -- Abstract: The thermal shield for ITER magnet feeder plays the role of preventing thermal radiation from the warm components to the cool superconductor and supercritical helium system. Heat loads were calculated for thermal analysis, then finite element model was established by ANSYS code. Thermal analysis was performed in order to check the temperature distribution and pressure drop of the thermal shield under normal operation state. Different materials (steel or aluminum) for the thermal shield were also checked. Thermal stress analysis was performed based on the results of thermal analyses. Compared analysis results with design criteria, it is demonstrated that the results of the simulation are within allowable design requirements and the design scheme can be applied to the detailed design

  18. Thermo-mechanical analysis of the thermal shield for ITER magnet feeder

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Mingzhun, E-mail: leimz@ipp.ac.cn; Song, Yuntao; Wang, Songke; Wang, Zhongwei; Liu, Sumei; Lu, Kun; Cheng, Yong

    2013-10-15

    Highlights: • We model the reasonable finite element model for feeder thermal shield. • We analyze the temperature distribution and pressure drop of the thermal shield. • Different materials for the thermal shield were analyzed. • Thermal stress analysis was performed and analysis result be applied to the detailed design. -- Abstract: The thermal shield for ITER magnet feeder plays the role of preventing thermal radiation from the warm components to the cool superconductor and supercritical helium system. Heat loads were calculated for thermal analysis, then finite element model was established by ANSYS code. Thermal analysis was performed in order to check the temperature distribution and pressure drop of the thermal shield under normal operation state. Different materials (steel or aluminum) for the thermal shield were also checked. Thermal stress analysis was performed based on the results of thermal analyses. Compared analysis results with design criteria, it is demonstrated that the results of the simulation are within allowable design requirements and the design scheme can be applied to the detailed design.

  19. Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses

    Science.gov (United States)

    Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; Wahl, W.

    2016-11-01

    Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and ramped operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (energy on the bulk shield walls and thereby the dose penetrating the shield walls. Designing supplemental shielding near the loss point using the analytic shielding model is shown to be inadequate because of its lack of geometry specification for the EM shower process. To predict the dose rates outside the tunnel requires detailed description of the geometry and materials that the beam losses will encounter inside the tunnel. Modern radiation shielding Monte-Carlo codes, like FLUKA, can handle this geometric description of the radiation transport process in sufficient detail, allowing accurate predictions of the dose rates expected and the ability to show weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. This made the effective shielding process for NSLS-II quite accurate and reliable. The principles used to provide supplemental shielding to the NSLS-II accelerators and

  20. Development of ITER shielding blanket prototype mockup by HIP bonding

    International Nuclear Information System (INIS)

    A prototype (∼900H x 1700W x 350T mm) of the ITER shielding blanket module has been fabricated following the previous successful fabrication of a small-scale (∼500H x 400W x 150T mm) and mid-scale (∼800H x 500W x 350T mm) mock-ups. This prototype incorporates most of key design features essential to the fabrication of the ITER shielding blanket module such as 1) the first wall heat sink made of Al2O3 dispersion strengthened Cu (DSCu) with built-in SS316L coolant tubes bonded to a massive SS316LN shield block, 2) toroidally curved first wall with a radius of 5106 mm while straight in poloidal direction, 3) coolant channels oriented in poloidal direction in the first wall and in toroidal direction in the shield block, 4) the first wall coolant channel routing to avoid the interference with the front access holes, 5) coolant channels drilled through the forged SS316LN-IG shield block, and 6) four front access holes of 30 mm in diameter penetrated through the first wall and the shield block. For the joining method, especially for the first wall/side wall parts and the shield block, the solid HIP (Hot Isostatic Pressing) process was applied. It is difficult to apply conventional joining methods such as field welding, brazing, explosion bonding and mechanical one-axial diffusion bonding to a wide area bonding because sufficient mechanical strengths can not be obtained and excessive deformations occurs. In order to solve these fabrication issues, HIP bonding was applied. The first wall stainless steel (SS) coolant tubes of 10 mm in inner diameter and l mm in thickness were sandwiched by semi-circular grooved DSCu plates at the first wall and the front region of the side wall, and by semi-circular grooved SS plates at the back region of the side wall. After assembling of these first wall/side wall parts with the shield block, they were simultaneously bonded by single step HIP in order to minimize thermal effects on the mechanical properties and to reduce the number

  1. Shielding analysis of the ITER/EDA NBI duct

    International Nuclear Information System (INIS)

    This report discusses the shielding properties of the ITER/EDA NBI ducts based on the current JCT design of the 24 superconductive toroidal field coils (the 24 TFC). The two-dimensional transport calculations have been performed by DOT 3.5. First, the neutron fluxes, dose to insulator and peak nuclear heating rate were calculated in the TFC and the NBI duct. The X-Y calculational model with detail description of the neutron source shape and the TFC geometry is used for that calculation. Second, the R-Z calculational model with detail description of the NBI components was set up. The nuclear heating in the NBI cryo panels and displacement damage in NBI copper grids were obtained in that calculation. In summary, it it concluded that the shielding performance of the current NBI duct design is enough to decrease all considered neutronics responses below the limits. (author)

  2. Shielding analysis of the ITER/EDA NBI duct

    Energy Technology Data Exchange (ETDEWEB)

    Zimin, S.; Takatsu, Hideyuki; Sato, Satoshi; Tsunematsu, Toshihide; Inoue, Takashi; Ohara, Yoshihiro [Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment; Maki, Koichi

    1994-08-01

    This report discusses the shielding properties of the ITER/EDA NBI ducts based on the current JCT design of the 24 superconductive toroidal field coils (the 24 TFC). The two-dimensional transport calculations have been performed by DOT 3.5. First, the neutron fluxes, dose to insulator and peak nuclear heating rate were calculated in the TFC and the NBI duct. The X-Y calculational model with detail description of the neutron source shape and the TFC geometry is used for that calculation. Second, the R-Z calculational model with detail description of the NBI components was set up. The nuclear heating in the NBI cryo panels and displacement damage in NBI copper grids were obtained in that calculation. In summary, it it concluded that the shielding performance of the current NBI duct design is enough to decrease all considered neutronics responses below the limits. (author).

  3. Reactor cavity cleanup system shielded filter installation

    International Nuclear Information System (INIS)

    The Seabrook Station reactor cavity cleanup system provides a flow path for refueling pool purification and drain down during plant refueling evolutions. The original system design included refueling pool surface skimmers and drains, a skimmer pump, an unshielded duplex basket type pump suction strainer and interconnecting stainless steel piping. The piping design utilized socket welded joints in small bore pipe with diaphragm values installed in the horizontal pipe runs downstream of the skimmer pump. The previously installed unshielded strainer in addition to the skimmer pump downstream piping components were determined to be inconsistent with Seabrook's proactive approach to dose reduction. To be consistent with ALARA (As Low As Reasonably Achievable) policy, a plant design change was authorized to install a lead shielded filter unit as a replacement for the existing duplex strainer. This filter unit, which utilizes multiple micron rating disposable basket type cartridges, has a threefold function of protecting the skimmer pump from large solids, providing bulk filtration of activated corrosion products from the refueling water in order to minimize CRUD buildup in downstream components, and enabling retrieval of foreign material drawn into the refueling pool drains

  4. Predictors of HbA1c levels in initial users of metformin

    NARCIS (Netherlands)

    Martono, Doti P; Hak, Eelko; Lambers Heerspink, Hiddo; Wilffert, Bob; Denig, Petra

    2016-01-01

    Objective The aim was to assess demographic and clinical factors as predictors of short (6 months) and long term (18 months) HbA1c levels in diabetes patients initiating metformin treatment. Research design and methods We conducted a cohort study including type 2 diabetes patients who received their

  5. Heat Shield Paves the Way for Commercial Space

    Science.gov (United States)

    2014-01-01

    The Phenolic-Impregnated Carbon Ablator (PICA) heat shield, a lightweight material designed to withstand high temperatures, was used for the Stardust’s reentry into Earth’s atmosphere. Hawthorne, California-based SpaceX later worked with the inventors at Ames Research Center to outfit PICA on its Dragon capsule, which is now delivering cargo to and from the International Space Station through NASA’s Commercial Resupply Services contracts program.

  6. Improved Assembly for Gas Shielding During Welding or Brazing

    Science.gov (United States)

    Gradl, Paul; Baker, Kevin; Weeks, Jack

    2009-01-01

    An improved assembly for inert-gas shielding of a metallic joint is designed to be useable during any of a variety of both laser-based and traditional welding and brazing processes. The basic purpose of this assembly or of a typical prior related assembly is to channel the flow of a chemically inert gas to a joint to prevent environmental contamination of the joint during the welding or brazing process and, if required, to accelerate cooling upon completion of the process.

  7. Modular Shielded Solar Panels Made using Low Cost Lamination Process

    OpenAIRE

    Stern, Theodore

    2007-01-01

    A modular, laminated solar panel approach has been demonstrated which uses high efficiency cells and allows application to a variety of smallsat footprints without customizing each application. The module design includes a contiguous integral shield which protects the solar cells more effectively from a variety of space environments, and also provides electromagnetic cleanliness to protect sensitive instruments from solar array generated EMI. The laminated approach also provides significant c...

  8. Effect of CSR shielding in the compact linear collider

    CERN Document Server

    Esberg, J; Apsimon, R; Schulte, D

    2014-01-01

    The Drive Beam complex of the Compact Linear Collider must use short bunches with a large charge making beam transport susceptible to unwanted effects of Coherent Synchrotron Radiation emitted in the dipole magnets. We present the effects of transporting the beam within a limited aperture which decreases the magnitude of the CSR wake. The effect, known as CSR shielding, eases the design of key components of the facility.

  9. Flexible shielding system for radiation protection

    Science.gov (United States)

    Babin, A.

    1972-01-01

    Modular construction of low cost flexible radiation shielding panels consists of water filled steels cans, zinc bromide windows, turntable unit, master-slave manipulators, and interlocking lead bricks. Easy modifications of shielding wall thicknesses are obtained by rearranging overall geometry of portable components.

  10. Antiproton annihilation physics annihilation physics in the Monte Carlo particle transport code particle transport code SHIELD-HIT12A

    DEFF Research Database (Denmark)

    Taasti, Vicki Trier; Knudsen, Helge; Holzscheiter, Michael;

    2015-01-01

    The Monte Carlo particle transport code SHIELD-HIT12A is designed to simulate therapeutic beams for cancer radiotherapy with fast ions. SHIELD-HIT12A allows creation of antiproton beam kernels for the treatment planning system TRiP98, but first it must be benchmarked against experimental data...

  11. Neutron shielding heat insulation material

    International Nuclear Information System (INIS)

    Purpose: To improve decceleration and absorption of neutrons by incorporating neutron moderators and neutron absorbers in asbestos to thereby increase hydrogen concentration. Constitution: A mixture consisting of crysotile asbestos, surface active agent and water is well stirred and compounded to open the crysotile asbestos filaments and prepare a high viscosity slurry. After adding hydroxides such as magnesium hydroxide, hydrated salts such as magnesium borate hydrate or water containing minerals such as alumina cement hydrate, or boron compound to the slurry, the slurry is charged in a predetermined die, and dried and compressed to prepare shielding heat insulation products. The crysotile asbestos has 18 - 15 wt.% of water of crystallinity in the structure and contains a considerably high hydrogen concentration that acts as neutron moderators. (Kawakami, Y.)

  12. Shielding superconductors with thin films

    CERN Document Server

    Posen, Sam; Catelani, Gianluigi; Liepe, Matthias U; Sethna, James P

    2015-01-01

    Determining the optimal arrangement of superconducting layers to withstand large amplitude AC magnetic fields is important for certain applications such as superconducting radiofrequency cavities. In this paper, we evaluate the shielding potential of the superconducting film/insulating film/superconductor (SIS') structure, a configuration that could provide benefits in screening large AC magnetic fields. After establishing that for high frequency magnetic fields, flux penetration must be avoided, the superheating field of the structure is calculated in the London limit both numerically and, for thin films, analytically. For intermediate film thicknesses and realistic material parameters we also solve numerically the Ginzburg-Landau equations. It is shown that a small enhancement of the superheating field is possible, on the order of a few percent, for the SIS' structure relative to a bulk superconductor of the film material, if the materials and thicknesses are chosen appropriately.

  13. Radiation Shielding Systems Using Nanotechnology

    Science.gov (United States)

    Chen, Bin (Inventor); McKay, Christoper P. (Inventor)

    2011-01-01

    A system for shielding personnel and/or equipment from radiation particles. In one embodiment, a first substrate is connected to a first array or perpendicularly oriented metal-like fingers, and a second, electrically conducting substrate has an array of carbon nanostructure (CNS) fingers, coated with an electro-active polymer extending toward, but spaced apart from, the first substrate fingers. An electric current and electric charge discharge and dissipation system, connected to the second substrate, receives a current and/or voltage pulse initially generated when the first substrate receives incident radiation. In another embodiment, an array of CNSs is immersed in a first layer of hydrogen-rich polymers and in a second layer of metal-like material. In another embodiment, a one- or two-dimensional assembly of fibers containing CNSs embedded in a metal-like matrix serves as a radiation-protective fabric or body covering.

  14. Shield verification and validation action matrix summary

    Energy Technology Data Exchange (ETDEWEB)

    Boman, C.

    1992-02-01

    WSRC-RP-90-26, Certification Plan for Reactor Analysis Computer Codes, describes a series of action items to be completed for certification of reactor analysis computer codes used in Technical Specifications development and for other safety and production support calculations. Validation and verification are integral part of the certification process. This document identifies the work performed and documentation generated to satisfy these action items for the SHIELD, SHLDED, GEDIT, GENPRT, FIPROD, FPCALC, and PROCES modules of the SHIELD system, it is not certification of the complete SHIELD system. Complete certification will follow at a later date. Each action item is discussed with the justification for its completion. Specific details of the work performed are not included in this document but can be found in the references. The validation and verification effort for the SHIELD, SHLDED, GEDIT, GENPRT, FIPROD, FPCALC, and PROCES modules of the SHIELD system computer code is completed.

  15. Electromagnetic interference shielding effectiveness of monolayer graphene.

    Science.gov (United States)

    Hong, Seul Ki; Kim, Ki Yeong; Kim, Taek Yong; Kim, Jong Hoon; Park, Seong Wook; Kim, Joung Ho; Cho, Byung Jin

    2012-11-16

    We report the first experimental results on the electromagnetic interference (EMI) shielding effectiveness (SE) of monolayer graphene. The monolayer CVD graphene has an average SE value of 2.27 dB, corresponding to ~40% shielding of incident waves. CVD graphene shows more than seven times (in terms of dB) greater SE than gold film. The dominant mechanism is absorption rather than reflection, and the portion of absorption decreases with an increase in the number of graphene layers. Our modeling work shows that plane-wave theory for metal shielding is also applicable to graphene. The model predicts that ideal monolayer graphene can shield as much as 97.8% of EMI. This suggests the feasibility of manufacturing an ultrathin, transparent, and flexible EMI shield by single or few-layer graphene. PMID:23085718

  16. Trimester-specific reference intervals for haemoglobin A(1c) (HbA(1c)) in pregnancy.

    LENUS (Irish Health Repository)

    O'Connor, Catherine

    2011-11-26

    Abstract Background: Diabetes in pregnancy imposes additional risks to both mother and infant. These increased risks are considered to be primarily related to glycaemic control which is monitored by means of glycated haemoglobin (HbA(1c)). The correlation of HbA(1c) with clinical outcomes emphasises the need to measure HbA(1c) accurately, precisely and for correct interpretation, comparison to appropriately defined reference intervals. Since July 2010, the HbA(1c) assay in Irish laboratories is fully metrologically traceable to the IFCC standard. The objective was to establish trimester-specific reference intervals in pregnancy for IFCC standardised HbA(1c) in non-diabetic Caucasian women. Methods: The authors recruited 311 non-diabetic Caucasian pregnant (n=246) and non-pregnant women (n=65). A selective screening based on risk factors for gestational diabetes was employed. All subjects had a random plasma glucose <7.7 mmol\\/L and normal haemoglobin level. Pregnancy trimester was defined as trimester 1 (T1, n=40) up to 12 weeks +6 days, trimester 2 (T2, n=106) 13-27 weeks +6 days, trimester 3 (T3, n=100) >28 weeks to term. Results: The normal HbA(1c) reference interval for Caucasian non-pregnant women was 29-37 mmol\\/mol (Diabetes Control and Complications Trial; DCCT: 4.8%-5.5%), T1: 24-36 mmol\\/mol (DCCT: 4.3%-5.4%), T2: 25-35 mmol\\/mol (DCCT: 4.4%-5.4%) and T3: 28-39 mmol\\/mol (DCCT: 4.7%-5.7%). HbA(1c) was significantly decreased in trimesters 1 and 2 compared to non-pregnant women. Conclusions: HbA(1c) trimester-specific reference intervals are required to better inform the management of pregnancies complicated by diabetes.

  17. The use of nipple shields: A review

    Directory of Open Access Journals (Sweden)

    Selina eChow

    2015-10-01

    Full Text Available A nipple shield is a breastfeeding aid with a nipple-shaped shield that is positioned over the nipple and areola prior to nursing. Nipple shields are usually recommended to mothers with flat nipples or in cases in which there is a failure of the baby to effectively latch onto the breast within the first two days postpartum. The use of nipple shields is a controversial topic in the field of lactation. Its use has been an issue in the clinical literature since some older studies discovered reduced breast milk transfer when using nipple shields, while more recent studies reported successful breastfeeding outcomes. The purpose of this review was to examine the evidence and outcomes with nipple shield use. Methods: A literature search was conducted in Ovid MEDLINE, OLDMEDLINE, EMBASE Classic, EMBASE, Cochrane Central Register of Controlled Trials and CINAHL. The primary endpoint was any breastfeeding outcome following nipple shield use. Secondary endpoints included the reasons for nipple shield use and the average/median length of use. For the analysis, we examined the effect of nipple shield use on physiological responses, premature infants, mothers’ experiences, and health professionals’ experiences. Results: The literature search yielded 261 articles, 14 of which were included in this review. Of these 14 articles, three reported on physiological responses, two reported on premature infants, eight reported on mothers’ experiences, and one reported on health professionals’ experiences. Conclusion: Through examining the use of nipple shields, further insight is provided on the advantages and disadvantages of this practice, thus allowing clinicians and researchers to address improvements on areas that will benefit mothers and infants the most.

  18. 超高速撞击玄武岩及Kevlar纤维布填充防护结构研究%THE OPTIMAL STRUCTURAL DESIGN OF STUFFED SHIELDS WITH BASALT AND KEVLAR FIBER CLOTHES AGAINST HYPERVELOCITY IMPACTING

    Institute of Scientific and Technical Information of China (English)

    张宝玺; 哈跃; 邓云飞; 庞宝君

    2012-01-01

    The impact ballistic performances of stuffed whipple shields with basalt and Kevlar fiber clothes are investigated by two-stage light gas gun facilities. Protective performance,damage morphology and mechanism of stuffed material and cabm walls are obtained, compared with the impact limit curve of Nextel/Kevlar stuffed whipple shields. In addition, the influence of epoxy resin coating on the protective performance are discussed. The data shows that stuffed whipple shields with basalt and kevlar fiber clothes have excellent protective properties in the high impact velocity. Coating with epoxy resin glue improve the prevention performance. Basalt fibers absorb energy by breaking projectile. Kevlar fibers have plastic deformation and fracture. Melting phenomenon and carbonation process appear in the hypervelocity regions.%利用二级轻气炮对玄武岩及Kevlar纤维布填充Whipple防护结构进行了超高速撞击实验研究.以Nextel/Kevlar撞击极限曲线为参照,分析了双层未涂胶玄武岩及Kevlar纤维布填充防护结构和双层涂环氧树脂胶玄武岩及Kevlar纤维布填充防护结构的防护性能、填充材料及舱壁的损伤情况.实验表明:双层未涂胶玄武岩及Kevlar纤维布填充防护结构和双层涂环氧树脂胶玄武岩及Kevlar纤维布填充防护结构在高速区都具有优良的防护性能.此外.通过涂环氧树脂胶改善了玄武岩及Kevlar纤维布填充防护结构在高速区的防护性能.Kevlar纤维丝在低速区主要依靠塑性变形及断裂吸收弹丸的动能,玄武岩纤维丝在高速区主要依靠脆性断裂及高温碳化将弹丸破碎或融化为尺寸更小的碎片或熔球,减轻了对舱壁的损伤.玄武岩及Kevlar纤维丝在高速区存在高温熔化及碳化现象.

  19. Review of the presented papers for the sixth international conference on radiation shielding

    International Nuclear Information System (INIS)

    Detailed review has been carried out on technical papers which were presented to the Sixth International Conference on Radiation Shielding, held in Tokyo, from May 16 to 20, 1983. We took into account 131 papers of which preprints were available during the Conference. The results of the review are described for each paper, including its originality, essential features, conclusions obtained and its applicability to shielding design, etc. Summary for each session are also included. (author)

  20. Superconducting Magnetic Shield of the Beam Vacuum Chamber for ALICE Muon Spectrometer

    CERN Document Server

    Shishov, Yu A; CERN. Geneva; Tsvineva, A G

    1997-01-01

    The operation of the dipole magnet of the ALICE muon spectrometer will require the ramping of the magnetic field in it according to the acceleration of the LHC beam. For the superconducting dipole magnet the ramping of the field will complicate the design of the magnet. To avoid the ramping of the magnetic field in the dipole magnet we propose to shield the LHC vacuum chamber inside of the dipole by the superconducting magnetic shield.

  1. Calculating magnetic shielding effectiveness for high-power dc comparator by magnetic circuit method

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-wei; REN Shi-yan

    2007-01-01

    Magnetic shielding is very important in the design of a high-power dc comparator. This paper addressed the application of magnetic circuit method to calculate the magnetic shielding effectiveness of high-power dc comparators when an external radial magnetic field is added. The mathematical relationship between the magnetic shielding effectiveness and the parameters of the magnetic shielding body were obtained. To verify the validity of the calculation method, we developped a procedure to measure the magnetic shielding effectiveness of the magnetic body by measuring the induction voltage of the detection winding instead of the magnetic intensity at a point in the magnetic shielding body, making the manipulation much easier. The result calculated with the magnetic circuit method turns out to be closer to the measured one compared with that calculated with a conventional algorithm proposed by Ren, suggesting that the magnetic circuit method is an applicable tool for estimating the toroidal cavity magnetic shielding effectiveness of a heavy current comparator when a radial magnetic field is added.

  2. Foam-Reinforced Polymer Matrix Composite Radiation Shields Project

    Data.gov (United States)

    National Aeronautics and Space Administration — New and innovative lightweight radiation shielding materials are needed to protect humans in future manned exploration vehicles. Radiation shielding materials are...

  3. Improved Metal-Polymeric Laminate Radiation Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposed Phase I program, a multifunctional lightweight radiation shield composite will be developed and fabricated. This structural radiation shielding...

  4. Neutronics analysis of inboard shielding capability for a DEMO fusion reactor CFETR

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Songlin; Li, Jiangang [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Zheng, Shanliang, E-mail: shanliang.zheng@ccfe.ac.uk [Culham Centre for Fusion Energy, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Mitchell, Neil [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2013-10-15

    The inboard shielding of a fusion reactor can be a crucial issue due to the limited space available in a tokamak configuration. It is necessary to assess the inboard shielding capability of DEMO for its initial design. In this paper, 1D and 3D neutronics models were developed based on a reference design of the Chinese Fusion Engineering Testing Reactor (CFETR). The neutron wall load (NWL) is in the range of 1.5–3 MW/m{sup 2} and the inboard shielding thickness is constrained within 40–70 cm in order to achieve the tritium self-sufficiency of the reactor. Referring to the detailed design of the ITER Toroidal Field Coils (TFCs) and using radiation hardening technology developed for ITER, the inboard blanket shielding capability and nuclear responses of the TFC are investigated for both FLiBe and Li{sub 4}SiO{sub 4} breeding blanket concepts. The impact of the gaps on shielding performance is discussed. Some suggestions on improving the inboard shielding performance for DEMO are also proposed.

  5. Evaluation of earth pressure on triple multi-face shield tunnel based on centrifuge model tests; Enshin mokei jikken ni yoru yoko sanren shield tunnel no doatsu hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Sugihara, Y.; Igarashi, H.; Fujisaki, K. [Kajima Corp., Tokyo (Japan)

    1995-12-20

    Recently, various needs for the utilization of underground space in urban areas, i.e., those for utilizing underground spaces with complicated cross-section shapes, have been encouraging the research and development of new shield methods. There have been considerations of building many tunnels with various cross-section shapes, such as horizontal double multi-face, horizontal triple multi-face, vertical double multi-face, MMST (multi-micro shield tunnel), and large-section tunnels with combinations of those shapes. The horizontal triple multi-face shield method is a new technique applied to underground railway stations with respect to construction period and safety. Since the horizontal triple multi-face shield tunnel has a laterally flatter shape than the former one circle shield tunnel, it is necessary to verify the validity of design using a usual method of evaluating earth pressure mainly for circle cross-sections. Therefore, the force on segments and deformation of surrounding soil were measured by using a centrifuge model equipment. Consequently, it was found that the earth pressure on horizontal triple multi-face shield segments in sandy ground is between earth pressure as evaluated by Terzaghi`s method and full earth pressure. 5 refs., 14 figs., 3 tabs.

  6. CACNA1C hypermethylation is associated with bipolar disorder.

    Science.gov (United States)

    Starnawska, A; Demontis, D; Pen, A; Hedemand, A; Nielsen, A L; Staunstrup, N H; Grove, J; Als, T D; Jarram, A; O'Brien, N L; Mors, O; McQuillin, A; Børglum, A D; Nyegaard, M

    2016-01-01

    The CACNA1C gene, encoding a subunit of the L-type voltage-gated calcium channel is one of the best-supported susceptibility genes for bipolar disorder (BD). Genome-wide association studies have identified a cluster of non-coding single-nucleotide polymorphisms (SNPs) in intron 3 to be highly associated with BD and schizophrenia. The mechanism by which these SNPs confer risk of BD appears to be through an altered regulation of CACNA1C expression. The role of CACNA1C DNA methylation in BD has not yet been addressed. The aim of this study was to investigate if CACNA1C DNA methylation is altered in BD. First, the methylation status of five CpG islands (CGIs) across CACNA1C in blood from BD subjects (n=40) and healthy controls (n=38) was determined. Four islands were almost completely methylated or completely unmethylated, while one island (CGI 3) in intron 3 displayed intermediate methylation levels. In the main analysis, the methylation status of CGI 3 was analyzed in a larger sample of BD subjects (n=582) and control individuals (n=319). Out of six CpG sites that were investigated, five sites showed significant hypermethylation in cases (lowest P=1.16 × 10(-7) for CpG35). Nearby SNPs were found to influence the methylation level, and we identified rs2238056 in intron 3 as the strongest methylation quantitative trait locus (P=2.6 × 10(-7)) for CpG35. In addition, we found an increased methylation in females, and no difference between bipolar I and II. In conclusion, we find that CACNA1C methylation is associated with BD and suggest that the regulatory effect of the non-coding risk variants involves a shift in DNA methylation. PMID:27271857

  7. Extraterrestrial Regolith Derived Atmospheric Entry Heat Shields

    Science.gov (United States)

    Hogue, Michael D.; Mueller, Robert P.; Sibille, Laurent; Hintze, Paul E.; Rasky, Daniel J.

    2016-01-01

    High-mass planetary surface access is one of NASAs technical challenges involving entry, descent and landing (EDL). During the entry and descent phase, frictional interaction with the planetary atmosphere causes a heat build-up to occur on the spacecraft, which will rapidly destroy it if a heat shield is not used. However, the heat shield incurs a mass penalty because it must be launched from Earth with the spacecraft, thus consuming a lot of precious propellant. This NASA Innovative Advanced Concept (NIAC) project investigated an approach to provide heat shield protection to spacecraft after launch and prior to each EDL thus potentially realizing significant launch mass savings. Heat shields fabricated in situ can provide a thermal-protection system for spacecraft that routinely enter a planetary atmosphere. By fabricating the heat shield with space resources from materials available on moons and asteroids, it is possible to avoid launching the heat-shield mass from Earth. Regolith has extremely good insulating properties and the silicates it contains can be used in the fabrication and molding of thermal-protection materials. In this paper, we will describe three types of in situ fabrication methods for heat shields and the testing performed to determine feasibility of this approach.

  8. Shielding Calculations for Positron Emission Tomography - Computed Tomography Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Baasandorj, Khashbayar [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yang, Jeongseon [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    Integrated PET-CT has been shown to be more accurate for lesion localization and characterization than PET or CT alone, and the results obtained from PET and CT separately and interpreted side by side or following software based fusion of the PET and CT datasets. At the same time, PET-CT scans can result in high patient and staff doses; therefore, careful site planning and shielding of this imaging modality have become challenging issues in the field. In Mongolia, the introduction of PET-CT facilities is currently being considered in many hospitals. Thus, additional regulatory legislation for nuclear and radiation applications is necessary, for example, in regulating licensee processes and ensuring radiation safety during the operations. This paper aims to determine appropriate PET-CT shielding designs using numerical formulas and computer code. Since presently there are no PET-CT facilities in Mongolia, contact was made with radiological staff at the Nuclear Medicine Center of the National Cancer Center of Mongolia (NCCM) to get information about facilities where the introduction of PET-CT is being considered. Well-designed facilities do not require additional shielding, which should help cut down overall costs related to PET-CT installation. According to the results of this study, building barrier thicknesses of the NCCM building is not sufficient to keep radiation dose within the limits.

  9. Adaptation of radiation shielding code to space environment

    Energy Technology Data Exchange (ETDEWEB)

    Okuno, Koichi; Hara, Akihisa (Hazama Corp., Tokyo (Japan))

    1992-12-01

    Recently, the trend to the development of space has heightened. To the development of space, many problems are related, and as one of them, there is the protection from cosmic ray. The cosmic ray is the radiation having ultrahigh energy, and there was not the radiation shielding design code that copes with cosmic ray so far. Therefore, the high energy radiation shielding design code for accelerators was improved so as to cope with the peculiarity that cosmic ray possesses. Moreover, the calculation of the radiation dose equivalent rate in the moon base to which the countermeasures against cosmic ray were taken was simulated by using the improved code. As the important countermeasures for the safety protection from radiation, the covering with regolith is carried out, and the effect of regolith was confirmed by using the improved code. Galactic cosmic ray, solar flare particles, radiation belt, the adaptation of the radiation shielding code HERMES to space environment, the improvement of the three-dimensional hadron cascade code HETCKFA-2 and the electromagnetic cascade code EGS 4-KFA, and the cosmic ray simulation are reported. (K.I.).

  10. Genetic and bibliographic information: CACNA1C [GenLibi

    Lifescience Database Archive (English)

    Full Text Available CACNA1C calcium channel, voltage-dependent, L type, alpha 1C subunit human Long QT Syndrome... (MeSH) Cardiovascular Diseases (C14) > Heart Diseases (C14.280) > Arrhythmias, Cardiac (C14.280.067) > Long QT Syndrome...) > Heart Defects, Congenital (C16.131.240.400) > Long QT Syndrome (C16.131.240.400.715) Pathological Condit...ions, Signs and Symptoms (C23) > Pathologic Processes (C23.550) > Arrhythmias, Cardiac (C23.550.073) > Long QT Syndrome (C23.550.073.547) 02A0514005 ...

  11. The dosimetry of eye shields for kilovoltage X-ray beams

    International Nuclear Information System (INIS)

    The objective of this work was to evaluate the dosimetry of tungsten eye shields for use with kilovoltage X-ray beam treatments. The eye shields, originally designed for megavoltage electron beams, were made of 2 mm tungsten thickness and inside diameters of 11.6 and 15.0 mm with optional aluminium caps of 0.5 and 1 mm thickness. The relative dosimetry of the eye shields were examined by measurement of transmission doses with full scatter conditions, central axis depth doses and beam profiles underneath the eye shield. The X-ray beams used in this study ranged in energy from 50 to 280 kVp. Transmission measurements were performed using an Advanced Markus ionisation chamber located at the surface of an RMI457 Solid Water phantom with a 3 cm diameter applicator flush against the phantom surface. Depth doses and profiles measurements were performed in a PTW MP3 scanning water tank with a PTW diamond detector. Results for transmission doses for the medium size eye shield increased from 1 to 22 % for 50–280 kVp while for the smaller eye shield the percentage dose increased from 3.5 to 30 % for the same energy range. There were minimal differences between using the 0.5 and 1 mm aluminium caps. Central axis depth doses measured with and without the eye shields demonstrated the 125 and 180 kVp beams had higher peak doses behind the eye shields. These results show that these tungsten eye shields are suitable for use with kilovoltage X-ray beams. However, the clinical impact needs to be considered for the higher X-ray beam energies.

  12. Carbon nanostructure composite for electromagnetic interference shielding

    Indian Academy of Sciences (India)

    Anupama Joshi; Suwarna Datar

    2015-06-01

    This communication reviews current developments in carbon nanostructure-based composite materials for electromagnetic interference (EMI) shielding. With more and more electronic gadgets being used at different frequencies, there is a need for shielding them from one another to avoid interference. Conventionally, metal-based shielding materials have been used. But due to the requirement of light weight, corrosion resistive materials, lot of work is being done on composite materials. In this research the forerunner is the nanocarbon-based composite material whose different forms add different characteristics to the composite. The article focusses on composites based on graphene, graphene oxide, carbon nanotubes, and several other novel forms of carbon.

  13. Radiation shielding techniques and applications. 2. Shielding and Mechanical Properties of Nurescell

    International Nuclear Information System (INIS)

    Nurescell is a new, unique composite of materials for radiation applications. Because of its physical properties, it is designed for shielding, storage, and containment of radiation and radioactive material. This paper presents measurements of gamma ray and neutron attenuation, radiation damage resistance, and mechanical properties of initial formulations of the Nurescell material. Nurescell is a polymer-based material. The polymer acts as the binding material for other constituents including oxides of aluminum, iron, bismuth, and/or lead, bismuth metal, and tungsten carbide. Table I gives several of the compositions that have been tested. The first four contain various amounts of aluminum, iron, and lead oxide. Material E contains bismuth oxide, material G contains bismuth metal, and material Nu-G contains tungsten carbide. Gamma-ray and fast neutron shielding characteristics were determined for several Nurescell formulations. Gamma-ray tests included 60Co (average energy 1.25 MeV) and 241Am (60 keV). The high-energy gamma rays emitted by 60Co are typically used as a reference for shielding calculations in the nuclear power industry. The low-energy gamma rays given off by 241Am are used to give an estimate of the equivalent atomic number Z of the material since the mass attenuation coefficient at this energy is highly dependent on Z. A simple, narrow-beam geometry was approximated, and the penetrating radiation was detected with a standard NaI detector and scaler. Results are given in Table I. Fast neutron-removal cross-section (Σr) measurements utilized a PuBe neutron source with an average energy of ∼4 MeV and a Bonner Sphere neutron spectrometer system. To determine the removal cross section, the number of neutrons in the energy range >1 eV was integrated from the Bonner Sphere results. Shielding samples had a cross-sectional area of 30x30 cm. This area may cause some error in this measurement since the neutron mean-free-path length is approaching this

  14. Dynamics and phase transitions in A 1C 60 compounds

    Science.gov (United States)

    Schober, H.; Renker, B.; Heid, R.; Tölle, A.

    1997-02-01

    We present an overview of extensive inelastic neutron scattering experiments carried out on powders of A 1C 60. The various phases leave strong fingerprints in the microscopic dynamics confirming the solid-state chemical reactions. The strong kinetic phase transitions can be followed in real time and turn out to be highly complex.

  15. CACNA1C hypermethylation is associated with bipolar disorder

    DEFF Research Database (Denmark)

    Starnawska, A; Demontis, D; Pen, A;

    2016-01-01

    The CACNA1C gene, encoding a subunit of the L-type voltage-gated calcium channel is one of the best-supported susceptibility genes for bipolar disorder (BD). Genome-wide association studies have identified a cluster of non-coding single-nucleotide polymorphisms (SNPs) in intron 3 to be highly...

  16. Safety analysis report for packaging: the ORNL lithium hydroxide fire and impact shield

    International Nuclear Information System (INIS)

    The ORNL Lithium Hydroxide Fire and Impact Shield and its packaging were designed and fabricated at Oak Ridge National Laboratory to permit the transport of Type B quantities of radioactive material and limited quantities of fissionable material. The shield and its packaging were evaluated analytically and experimentally to determine its compliance with the applicable regulations governing containers in which radioactive and fissile materials are transported, and that evaluation is the subject of this report. Computational and test procedures were used to determine the structural integrity and thermal behavior of the shield relative to the general standards for normal conditions of transport and the standards for the hypothetical accident conditions. The results of the evaluation demonstrate that the shield and its packaging are in compliance with the applicable regulations. 16 references, 8 figures, 5 tables

  17. Applications of point kernel estimates to the fuel conditioning facility shield test program

    International Nuclear Information System (INIS)

    Use of a multigroup point kernel gamma ray attenuation program helped Argonne National Laboratory complete a project that verified the integrity of the shields in the Fuel Conditioning Facility (FCF). Test procedures were developed based on predictions of dose equivalents as functions of source strengths, source-to-detector distances, and thickness of various shield materials. Tables and plots of these data were used to select and position the test sources and to compare as-built shields to their design thicknesses. Part of the program involved a study of the penetration of photons from spent fuel as a function of cooling time. Such information is important to estimate the effectiveness of FCF shields on mixed fission product sources from various reactors

  18. Structural and Shielding Safety of a Transport Package for Radioisotope Sealed Source Assembly

    International Nuclear Information System (INIS)

    As some kinds of radioisotope (RI) sealed source are produced by HANARO research reactor, a demand of RI transport package is increasing gradually. Foreign countries, which produce the various RIs, have the intrinsic model of the RI transport package. It is necessary to develop a RI and its transport package simultaneously. It is difficult to design a shielding part for this transport package because the passage for this source assembly should be provided from the center of shielding part to the outside of the package. In order to endure the accident conditions such as a 9 m drop and puncture, this transport package consists of the guide tubes, a gamma shield and a shock absorber. This paper describe that a shielding and structural safety of RI sealed source transport package are evaluated under the accident conditions

  19. Investigation on radiation shielding parameters of ordinary, heavy and super heavy concretes

    Directory of Open Access Journals (Sweden)

    Singh Vishwaanath P.

    2014-01-01

    Full Text Available Shielding of a reactor is required for protection of people and environment during normal operation and accidental situations. In the present paper we investigated the shielding parameters viz. mass attenuation coefficients, linear attenuation coefficients, tenth-value layer, effective atomic numbers, kerma relative to air and exposure buildup factors for gamma-ray for ordinary, heavy, and super heavy concretes. Macroscopic effective removal cross-sections for fast neutron had also been calculated. Ordinary concrete is economically suitable for mixture high energy gamma-ray and neutron as it has large weight fraction of low-Z as compared with super heavy concretes to slow down the neutron. Super heavy concretes are superior shielding for both reactor operation and accident situations. The study is useful for optimizing for shielding design and radiation protection in the reactors.

  20. Laboratory tests on neutron shields for gamma-ray detectors in space

    CERN Document Server

    Hong, J; Hailey, C J

    2000-01-01

    Shields capable of suppressing neutron-induced background in new classes of gamma-ray detectors such as CdZnTe are becoming important for a variety of reasons. These include a high cross section for neutron interactions in new classes of detector materials as well as the inefficient vetoing of neutron-induced background in conventional active shields. We have previously demonstrated through Monte-Carlo simulations how our new approach, supershields, is superior to the monolithic, bi-atomic neutron shields which have been developed in the past. We report here on the first prototype models for supershields based on boron and hydrogen. We verify the performance of these supershields through laboratory experiments. These experimental results, as well as measurements of conventional monolithic neutron shields, are shown to be consistent with Monte-Carlo simulations. We discuss the implications of this experiment for designs of supershields in general and their application to future hard X-ray/gamma-ray experiments...

  1. Reflector and Shield Material Properties for Project Prometheus

    Energy Technology Data Exchange (ETDEWEB)

    J. Nash

    2005-11-02

    This letter provides updated reflector and shield preliminary material property information to support reactor design efforts. The information provided herein supersedes the applicable portions of Revision 1 to the Space Power Program Preliminary Reactor Design Basis (Reference (a)). This letter partially answers the request in Reference (b) to provide unirradiated and irradiated material properties for beryllium, beryllium oxide, isotopically enriched boron carbide ({sup 11}B{sub 4}C) and lithium hydride. With the exception of {sup 11}B{sub 4}C, the information is provided in Attachments 1 and 2. At the time of issuance of this document, {sup 11}B{sub 4}C had not been studied.

  2. Shielding of the GERDA experiment against external gamma background

    International Nuclear Information System (INIS)

    The GERmanium Detector Array (GERDA) experiment will search for neutrinoless double beta decay of 76Ge and is currently under construction at the INFN Laboratori Nazionali del Gran Sasso (LNGS) in Italy. The basic design of GERDA is the use of cryogenic liquid and water of high purity as a superior shield against the hitherto dominant background from external gamma radiation. In this paper we show by Monte Carlo simulations and analytical calculations how GERDA was designed to suppress this background at Qββ(76Ge)=2039keV to a level of about 10-4cts/(keVkgy).

  3. Shielded chamber control stations: an answer to radiological protection requirements

    International Nuclear Information System (INIS)

    This study, carried out at the radiometallurgy laboratory of the Fontenay-aux-Roses Nuclear Research Centre, is based on an ergonomic approach. It shows that the shielded chamber control station, designed for human protection against ionizing radiations, demands an effort of adaptation on the part of the operator. This station does in fact meet radiological protection obligations but would benefit from certain improvements aimed at reducing the secondary fatigue of manipulators already under the strain of adapting to the machine. Fields in which improvements and/or changes are desirable have been investigated with special reference to telemanipulators. New and better designed instruments will soon appear on the telemanipulator market

  4. Effects of Rutaecarpine on Hydrogen Peroxide-Induced Apoptosis in Murine Hepa-1c1c7 Cells

    OpenAIRE

    Lee, Sung-Jin; Ahn, Hyunjin; Nam, Kung-Woo; Kim, Kyeong Ho; Mar, Woongchon

    2012-01-01

    The aim of this study was to investigate the inhibitory effects of rutaecarpine on DNA strand breaks and apoptosis induced by hydrogen peroxide (H2O2) in murine Hepa-1c1c7 cells. Oxidative DNA damage was estimated by nuclear condensation assessment, fluorescence-activated cell sorting analysis, and Comet assay. Rutaecarpine inhibited cell death induced by 500 μM H2O2, as assessed by 4',6-diamidino-2-phenylindole (DAPI) staining. Treatment with rutaecarpine reduced the number of DNA strand bre...

  5. SREBP-1c regulates glucose-stimulated hepatic clusterin expression

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gukhan [Department of Pharmacology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of); Kim, Geun Hyang; Oh, Gyun-Sik; Yoon, Jin [Department of Pharmacology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of); Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of); Kim, Hae Won [Department of Pharmacology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of); Kim, Min-Seon [Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of); Kim, Seung-Whan, E-mail: swkim7@amc.seoul.kr [Department of Pharmacology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of); Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul 138-736 (Korea, Republic of)

    2011-05-20

    Highlights: {yields} This is the first report to show nutrient-regulated clusterin expression. {yields} Clusterin expression in hepatocytes was increased by high glucose concentration. {yields} SREBP-1c is directly involved in the transcriptional activation of clusterin by glucose. {yields} This glucose-stimulated activation process is mediated through tandem E-box motifs. -- Abstract: Clusterin is a stress-response protein that is involved in diverse biological processes, including cell proliferation, apoptosis, tissue differentiation, inflammation, and lipid transport. Its expression is upregulated in a broad spectrum of diverse pathological states. Clusterin was recently reported to be associated with diabetes, metabolic syndrome, and their sequelae. However, the regulation of clusterin expression by metabolic signals was not addressed. In this study we evaluated the effects of glucose on hepatic clusterin expression. Interestingly, high glucose concentrations significantly increased clusterin expression in primary hepatocytes and hepatoma cell lines, but the conventional promoter region of the clusterin gene did not respond to glucose stimulation. In contrast, the first intronic region was transcriptionally activated by high glucose concentrations. We then defined a glucose response element (GlRE) of the clusterin gene, showing that it consists of two E-box motifs separated by five nucleotides and resembles carbohydrate response element (ChoRE). Unexpectedly, however, these E-box motifs were not activated by ChoRE binding protein (ChREBP), but were activated by sterol regulatory element binding protein-1c (SREBP-1c). Furthermore, we found that glucose induced recruitment of SREBP-1c to the E-box of the clusterin gene intronic region. Taken together, these results suggest that clusterin expression is increased by glucose stimulation, and SREBP-1c plays a crucial role in the metabolic regulation of clusterin.

  6. RANTES In1.1C allele polymorphisms in 13 Chinese ethnic populations

    Institute of Scientific and Technical Information of China (English)

    QIAN Yuan; SUN Hao; CHU Jia-you

    2009-01-01

    Background The In1.1C single nucleotide polymorphism (SNP) allele results in reduced RANTES transcription, which is associated with increased frequency of HIV-1 infection, and rapid progression to AIDS among HIV-1-infected individuals. This study aimed to study the mutant frequency and polymorphism of RANTES in Chinese populations.Methods The genotypes of RANTES In1.1C were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with the digestion of restriction endonuclease Mbo Ⅱ.Results Of the 617 individuals, 290 (47%) were carriers of the RANTES In1.1C allele, 52 of whom were homozygotes,whereas 238 were heterozygotes. The frequency of the RANTES In1.1C allele in those tested individuals was 0.2840.The frequencies of Inl.lC allele vaded from 0.07-0.27 in most of the populations in South-west China except for the two Lisu populations, while the frequencies of In1.1C spans from 0.35 to 0.45 in North-west China. The prevalence of the allele varied substantially between the South-west groups and North-west groups (X2=7.838, P=0.006).Conclusions The prevalence of the RANTES In1.1C allele varies substantially between the South-west groups and North-west groups. There is no significant difference between the groups with different languages, which suggests that language relationship is not consistent with the genetic relationship. These results have important implications for the design, assessment, and implementation of HIV-1 vaccines.

  7. Hemoglobin A1c and arterial and ventricular stiffness in older adults.

    Directory of Open Access Journals (Sweden)

    Susan J Zieman

    Full Text Available OBJECTIVE: Arterial and ventricular stiffening are characteristics of diabetes and aging which confer significant morbidity and mortality; advanced glycation endproducts (AGE are implicated in this stiffening pathophysiology. We examined the association between HbA(1c, an AGE, with arterial and ventricular stiffness measures in older individuals without diabetes. RESEARCH DESIGN & METHODS: Baseline HbA(1c was measured in 830 participants free of diabetes defined by fasting glucose or medication use in the Cardiovascular Health Study, a population-based cohort study of adults aged ≥ 65 years. We performed cross-sectional analyses using baseline exam data including echocardiography, ankle and brachial blood pressure measurement, and carotid ultrasonography. We examined the adjusted associations between HbA(1c and multiple arterial and ventricular stiffness measures by linear regression models and compared these results to the association of fasting glucose (FG with like measures. RESULTS: HbA(1c was correlated with fasting and 2-hour postload glucose levels (r = 0.21; p<0.001 for both and positively associated with greater body-mass index and black race. In adjusted models, HbA(1c was not associated with any measure of arterial or ventricular stiffness, including pulse pressure (PP, carotid intima-media thickness, ankle-brachial index, end-arterial elastance, or left ventricular mass (LVM. FG levels were positively associated with systolic, diastolic and PP and LVM. CONCLUSIONS: In this sample of older adults without diabetes, HbA(1c was not associated with arterial or ventricular stiffness measures, whereas FG levels were. The role of AGE in arterial and ventricular stiffness in older adults may be better assessed using alternate AGE markers.

  8. Shielded ADR Magnets For Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase II program will concentrate on manufacturing of qualified low-current, light-weight, 10K ADR magnets for space application. Shielded ADR solenoidal...

  9. Long Duration Space Shelter Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) has developed fiber reinforced ceramic composites for radiation shielding that can be used for external walls in long duration manned...

  10. Long Duration Space Shelter Shielding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Physical Sciences Inc. (PSI) has developed a ceramic composite material system that is more effective for shielding both GCR and SPE than aluminum. The composite...

  11. Data of evolutionary structure change: 1C4XA-2OG1B [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1C4XA-2OG1B 1C4X 2OG1 A B ---TVEIIEKRFPSGT---LASHALVAGDPQSPAVVLLH...EEEEEEE HHHHHHHHHHHHH 0 1C4X... A 1C4XA FPSGT---LASHA ...645107269287 4.700198173522949 1 1C4X... A 1C4XA

  12. Shield structure for a nuclear reactor

    International Nuclear Information System (INIS)

    An improved nuclear reactor shield structure is described for use where there are significant amounts of fast neutron flux above an energy level of approximately 70 keV. The shield includes structural supports and neutron moderator and absorber systems. A portion at least of the neutron moderator material is magnesium oxide either alone or in combination with other moderator materials such as graphite and iron. (U.K.)

  13. Electromagnetic shielding with polypyrrole-coated fabrics

    OpenAIRE

    Avloni, J.; L. De Florio; Henn, A. R.; R. Lau; Ouyang, M.; Sparavigna, A.

    2006-01-01

    Several shielding applications, to protect human health and electronic devices against dangerous effects of electromagnetic radiation, require solutions that fabrics can suitably fulfill. Here, we will investigate the electromagnetic interference shielding effectiveness of polypyrrole-coated polyester textiles, in the frequency range 100-1000 MHz. Insertion losses for several conductive fabrics with different surface resistivity ranging from 40 Ohm till the very low value of 3 Ohm were evalua...

  14. APOLLO2 code self-shielding formalism

    International Nuclear Information System (INIS)

    This report describes the various self-shielding methods used in the APOLLO2 code for treating one resonant nucleus or a mixture of resonant nuclei. The methods are expounded in chronological order. First of all, the methods dealing with one resonant isotope are explained. Then an original method dealing directly with a resonant mixture is detailed. This new method is also convenient for one resonant nucleus and leads, in that case, to interesting improvements in the self-shielding modeling. (author)

  15. Foamed Nanocomposites for EMI Shielding Applications

    OpenAIRE

    Molenberg, Isabel; Huynen, Isabelle; Baudouin, Anne-Christine; Bailly, Christian; Thomassin, Jean-Michel; Detrembleur, Christophe

    2010-01-01

    Throughout this chapter, we have seen that foamed polymer/CNTs nanocomposites make very good EMI shielding materials. They exhibit a high conductivity and a relatively low dielectric constant, leading to a high Shielding Effectiveness and a relatively low Reflectivity, although a compromise in CNT content must be found between a high SE and a low R. This was confirmed by measurement results and rheological measurements but also using a simple electrical equivalent model.

  16. Evaluation of tube shielding; Utvaerdering av tubskyddsmaterial

    Energy Technology Data Exchange (ETDEWEB)

    Hjoernhede, Anders; Westberg, Stig-Bjoern; Henderson, Pamela; Wetterstroem, Jonas; Jonasson, Anna

    2007-12-15

    Problems with soot-blowing have increased recently because of the poor fuel quality. Studies show that removing all the deposit by soot-blowing increases the metal loss of the superheaters, which drastically shortens component lifetimes. A simple, effective and common way of increasing the lifetime is to use tube shielding. Austenitic stainless steels seem to be the type of material most commonly used for tube shielding. It is thought that they give better protection against material removal than ferritic steels, but the cost of austenitics is several times greater than ferritic steels. It is clear that there is a significant economic advantage in choosing the right material for tube shielding, even though it might be expected that the cheaper materials do not perform as well as the more expensive ones. The reason for the study reported here is that very little material data exists in the literature. Few, if any tests have been performed to study the choice of material for tube shielding. The goal was to compare and evaluate a number of materials in a boiler to see if it is possible to replace the shielding material presently used with cheaper alternatives. About a dozen different shielding materials were installed and exposed for 4000 hours on primary- and secondary superheaters in a waste-fired boiler in Norrkoeping (Haendeloe Boiler 14.75MW). In total, 130 m of test material were installed and measured in several positions: a least 150 thickness measurements, before and after, were made on every tube shield. The results showed that the greatest attack was found on the secondary superheater shielding, where both the gas- and steam temperatures were higher. When considering cost and lifetime Sicromal 10 and 12 (however not Sicromal 8) and 15Mo3 are recommended as being better than 253 MA. The results should be of interest to most plants firing biomass or waste

  17. Influence of Shielding Arrangement on ECT Sensors

    Directory of Open Access Journals (Sweden)

    J. L. Fernandez Marron

    2006-09-01

    Full Text Available This paper presents a full 3D study of a shielded ECT sensor. The spatialresolution and effective sensing field are obtained by means of Finite Element Methodbased simulations and are the compared to a conventional sensor's characteristics. Aneffective improvement was found in the sensitivity in the pipe cross-section, resulting inenhanced quality of the reconstructed image. The sensing field along the axis of the sensoralso presents better behaviour for a shielded sensor.

  18. Measurement accuracy in shielded magnetic fields

    International Nuclear Information System (INIS)

    The measurement error due to both the probe size averaging effect and the coil arrangement is investigated when magnetic field measurements are performed in close proximity to different planar shields. The analysis is carried on through a hybrid FEM/BEM model which employs the 'thin shield' technique. Ferromagnetic, pure conductive and multilayer screens are taken into consideration and an estimation of the errors for concentric and non-concentric coil probes is given. The numerical results are validated by experiments

  19. Design of Electric Signal Acquisition System in CO_2 Gas Shielded Welding%CO_2气体保护焊电信号采集系统设计

    Institute of Scientific and Technical Information of China (English)

    郭险峰; 郭宗光; 吴春梅; 董云峰; 孙鹏翔

    2012-01-01

    The hall current sensors,the hall voltage sensor and the MSP430F5529 microcontroller form electric signal acquisition hardware system in CO2 gas shielded welding,signal data transmission via communication between USB module of the MSP430 microcontroller and the host.Calling the API function of windows and MSP430,writting software in VC + + language,host software and MSP430 software form the signal acquisition software system.%利用霍尔电流传感器、霍尔电压传感器和MSP430F5529单片机组成CO2气体保护焊电信号采集的硬件系统,电信号数据传输则通过MSP430单片机内置的USB模块与主机的通信来完成。利用VC++语言并调用Windows和MSP430的API函数编写主机软件和单片机软件,由此组成电信号采集的软件系统。

  20. Reactor shielding. Report of a panel

    International Nuclear Information System (INIS)

    Reactor shielding is necessary that people may work and live in the vicinity of reactors without receiving detrimental biological effects and that the necessary materials and instrumentation for reactor operation may function properly. Much of the necessary theoretical work and experimental measurement has been accomplished in recent years. Scientists have developed some very sophisticated methods which have contributed to a more thorough understanding of the problems involved and have produced some very reliable results leading to significant reductions in shield configurations. A panel of experts was convened from 9 to 13 March 1964 in Vienna at the Headquarters of the International Atomic Energy Agency to discuss the present status of reactor shielding. The participants were prominent shielding experts from most of the laboratories engaged in this field throughout the world. They presented status reports describing the past history and plans for further development of reactor shielding in their countries and much valuable discussion took place on some of the most relevant aspects of reactor shielding. All this material is presented in this report, together with abstracts of the supporting papers read to the Panel

  1. Neue biosensorische Prinzipien für die Hämoglobin-A1c Bestimmung

    Science.gov (United States)

    Stöllner, Daniela

    2002-06-01

    mellitus. It is measured as the percentage of total hemoglobin. Up to 5 % HbA1c are considered as normal whereas in diabetic subjects it could be elevated from 5-20 %. In addition to amperometric biosensors for glucose self monitoring which have been successfully applied in diabetes management, biosensors for HbA1c would be an useful supplement for a comprehensive diabetes control. Objective of this work was to develop and compare amperometric biosensors for determination of HbA1c based on enzymatic and immunochemical methods. For the enzyme based HbA1c assay a novel fructosamine oxidase (FAO) derived from marine yeast Pichia pastoris, strain N1-1 was utilized. It recognizes and oxidatively degrades fructosyl-valine (FV) which corresponds to the glycated N-terminus of the beta-chain of HbA1c and therefore is regarded as a model compound for HbA1c. Hydrogen peroxide which is liberated by the FAO during FV conversion was indicated optically in a horseradish peroxidase (POD) coupled reaction and electrochemically. For the biosensor the FAO was embedded in polyvinyl alcohol-stylbazole (PVA-SbQ) and fixed it in front of a Pt-electrode. So far, the measuring range of FV did not cover the clinically relevant range of HbA1c. Low specificity was assumed since enzyme activity also was obtained with glycated peptides, e.g. fructosyl-valine-glycine, not corresponding to the glycated N-terminus of the hemoglobin-beta-chain. For the immunosensor two immunoassays formats - heterogeneous sandwich and heterogeneous competitive - were tested. The assays were designed as follows: The competitive immunoassay was based on the immobilized synthetic glycated pentapeptide fructosyl-valine-histidine-leucine-threonine-proline (glkPP) utilized as HbA1c analogue. The peptide has an amino acid sequence corresponding to the N-terminus of the hemoglobin beta-chains and is capable for competition together with the HbA1c of the sample for the amount of a glucose oxidase (GOD)-labelled anti-HbA1c antibody

  2. Impedance change measurements of a superconducting shielded-core reactor

    International Nuclear Information System (INIS)

    A device was constructed using a stack of superconducting rings surrounding a ferrite rod, with the assembly inserted in a high turns count solenoid. Superconducting end pieces were also placed at either end of the rod to minimize flux leakage to the ferrite rod. The superconducting rings act as a magnetic shield to the ferrite, effectively eliminating the low reluctance path the ferrite offers. At a specific field the superconductor will be fully penetrated, placing the ferrite in the magnetic circuit and reducing the reactance offered by the solenoidal winding. In this mode of operation the shielded core reactor can be applied as a current limiting device. Results included in this paper, indicate that in the best design achieved leakage to the ferrite core could not be eliminated. The superconducting current induced by this leakage eliminated the low reluctance path of the ferrite by producing a counter-flux in the core exactly opposing the applied field. Shielding currents set up by penetration of the externally applied field were found to be minimal compared to the induced currents caused by leakage flux in the ferrite core

  3. Diagnostic X-Ray shielding : new data and new concepts

    International Nuclear Information System (INIS)

    Report No. 49 of the National Council on Radiation Protection and Measurement (NCRP 49, 1976) is currently the primary source of information to be used for design of protective barrier shielding for diagnostic x-ray facilities in the USA. However, a number of more recent publications have presented new methodologies and attenuation data for alternative shielding materials not discussed in Report No. 49. A nonlinear analytical model of photon transmission that accurately fits and parameterizes attenuation data has been developed. Use of this model simplifies primary and secondary barrier calculations and permits 'exact' solutions for secondary barriers. This presentation will describe the use of this model and present a recently acquired database of single and three phase attenuation measurements obtained with state-of-the-art monitoring equipment. This data set, which contains measurements from six diagnostic x-ray shielding materials, will be compared with experimental and theoretical transmission data found in the literature. The model, which has been shown to provide a robust and accurate method of portraying experimental attenuation data, will be used in the revision of NCRP 49 to specify the transmission characteristics of all protective materials. (author)

  4. Neutron and gamma ray transport calculations in shielding system

    Energy Technology Data Exchange (ETDEWEB)

    Masukawa, Fumihiro; Sakamoto, Hiroki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-03-01

    In the shields for radiation in nuclear facilities, the penetrating holes of various kinds and irregular shapes are made for the reasons of operation, control and others. These penetrating holes and gaps are filled with air or the substances with relatively small shielding performance, and radiation flows out through them, which is called streaming. As the calculation techniques for the shielding design or analysis related to the streaming problem, there are the calculations by simplified evaluation, transport calculation and Monte Carlo method. In this report, the example of calculation by Monte Carlo method which is represented by MCNP code is discussed. A number of variance reduction techniques which seem effective for the analysis of streaming problem were tried. As to the investigation of the applicability of MCNP code to streaming analysis, the object of analysis which are the concrete walls without hole and with horizontal hole, oblique hole and bent oblique hole, the analysis procedure, the composition of concrete, and the conversion coefficient of dose equivalent, and the results of analysis are reported. As for variance reduction technique, cell importance was adopted. (K.I.)

  5. Neutronic studies for the optimization of shield wall penetrations for laser IFE systems

    Energy Technology Data Exchange (ETDEWEB)

    Lafuente, A., E-mail: Lafuentemazu2@llnl.gov [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States); Latkowski, J.F.; Kramer, K.J.; Dunne, A.M. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer We provide insight on the impact of wall shield penetrations for IFE systems. Black-Right-Pointing-Pointer We establish guidelines for the selection of different variables linked to the pinhole's design. Black-Right-Pointing-Pointer We identify the requirements to enable manual maintenance during operation and propose the use of non-aligned double shield walls with pinholes. - Abstract: Building upon the inertial confinement fusion (ICF) technology developed for the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL), a laser-driven inertial fusion energy (LIFE) power plant is being designed. In this pre-conceptual design, the final optic is exposed to a variety of threats originating from the fusion target. These include prompt neutron and gamma fluxes, x-ray and ionic emissions. While x-rays and ions are stopped by the low-density chamber fill gas (6 {mu}g/cc xenon), neutrons and gamma-rays are not significantly attenuated. In order to limit the consequences of such threats onto the penultimate optic and the rest of the laser systems, a shielding wall stands between the target chamber area and the laser bay. An optical telescope arrangement allows for the laser beam propagation from the penultimate to the final optic, through a pinhole in the shielding wall. These pinholes attenuate the neutron flux and reduce effective dose rates such that laser bay maintenance can be performed by humans. An optimum design of this laser pinhole requires a good understanding of the different design trade-offs that exist between shielding performance and survivability of the laser optical elements and are outlined in this work. This paper provides insight on the impact and influence of the pinholes on the radiation doses in the laser bay, which is located on the opposite side of the concrete shielding wall. After addressing the difficulties of evaluating shields containing penetrations, it establishes a

  6. Manufacture of a shield prototype for primary wall modules

    International Nuclear Information System (INIS)

    In the frame of the BLANKET MODULE (BM) development for ITER, an R and D programme was implemented for the manufacture of a shield prototype by powder Hot Isostatic Pressing (HIPping). The manufactured shield is a full scale module No. 11a. Starting from a forged block of 1200 x 1200 x 500 mm, the main machining steps as deep drilling (1200 mm), 3D machining and sawing were performed. Tubes were 3D bent and large number of small parts were designed and machined. By welding together all the sub-parts we erected the main part of the water coolant circuit. Once the water circuit was built; the shield was completed using powder HIPping together with forged block embedding the tubes and their in a final solid part. The powder/solid HIP is used to minimize the number of BM seal welds in front of plasma. It increases the reliability of the components during operation. About 300 kg of stainless steel powder was densified together with the forged block. 3D measurement was done before and after the HIP cycle to collect the data to be compared with theoretical model. It allows to predict the main distortions of the solid bulk. Ultrasonic examination of the densified powder on the Stainless steel bulk and around the bended tubes was performed as well as mechanical characterization of the samples. The recess for stub key attachment on the vacuum vessel side, the hydraulic connector, the key for the primary wall panel attachment on the front side and the link between the four parallel water coolant circuits were then machined to achieve the shield prototype. (orig.)

  7. Manufacture of a shield prototype for primary wall modules

    International Nuclear Information System (INIS)

    In the frame of the blanket module (BM) development for ITER, an R and D programme was implemented for the manufacture of a shield prototype by powder hot isostatic pressing (HIPping). The manufactured shield is a full-scale module No. 11a. Starting from a forged block of 1350 mm x 1300 mm x 450 mm, the main machining steps as deep drilling (1200 mm), 3D machining and sawing were performed. Tubes were 3D bent and large number of small parts were designed and machined. By welding together all the sub-parts we erected the main part of the water coolant circuit. Once the water circuit was built; the shield was completed using powder HIPping together with forged block embedding the tubes in a final solid part. The powder/solid HIP is used to minimize the number of BM seal welds in front of plasma. It increases the reliability of the components during operation. About 300 kg of stainless steel powder was densified together with the forged block. 3D measurement was done before and after the HIP cycle to collect the data to be compared with theoretical model. It allows to predict the main distortions of the solid bulk. Ultrasonic examination of the densified powder on the stainless steel bulk and around the bended tubes was performed as well as mechanical characterization of the samples. The recess for stub key attachment on the vacuum vessel side, the hydraulic connector, the key for the primary wall panel attachment on the front side and the link between the four parallel water coolant circuits were then machined to achieve the shield prototype

  8. Progress and prospects of calculation methods for radiation shielding

    International Nuclear Information System (INIS)

    Progress in calculation methods for radiation shielding are reviewed based on the activities of research committees related to radiation shielding fields established in the Atomic Energy Society of Japan. A technological roadmap for the field of radiation shielding; progress and prospects for specific shielding calculation methods such as the Monte Carlo, discrete ordinate Sn transport, and simplified methods; and shielding experiments used to validate calculation methods are presented in this paper. (author)

  9. Numerical Models for the Study of Electromagnetic Shielding

    Directory of Open Access Journals (Sweden)

    POPA Monica

    2012-10-01

    Full Text Available The paper presents 2D and 3D models for the study of electromagnetic shielding of a coil. The magnetic fields are computed for defining the shielding effectiveness. Parametrized numerical studies were performed in order to established the influence of shield thickness and height on magnetic field in certain points located in the exterior of coil – shield setup and on induced power within the shield.

  10. Optimization of infrared and magnetic shielding of superconducting TiN and Al coplanar microwave resonators

    CERN Document Server

    Kreikebaum, John Mark; Livingston, William; Kim, Eunseong; Siddiqi, Irfan

    2016-01-01

    We present a systematic study of the effects of shielding on the internal quality factors (Qi) of Al and TiN microwave resonators designed for use in quantum coherent circuits. Measurements were performed in an adiabatic demagnetization refrigerator, where typical magnetic fields of 200 {\\mu}T are present at the unshielded sample stage. Radiation shielding consisted of 100 mK and 500 mK Cu cans coated with infrared absorbing epoxy. Magnetic shields consisted of Cryoperm 10 and Sn plating of the Cu cans. A 2.7 K radiation can and coaxial thermalization filters were present in all measurements. TiN samples with Qi = $1.3*10^6$ at 100 mK exhibited no significant variation in quality factor when tested with limited shielding. In contrast, Al resonators showed improved Qi with successive shielding, with the largest gains obtained from the addition of the first radiation and magnetic shields and saturating before the addition of Sn plating infrared absorbing epoxy.

  11. Optimization of infrared and magnetic shielding of superconducting TiN and Al coplanar microwave resonators

    Science.gov (United States)

    Kreikebaum, J. M.; Dove, A.; Livingston, W.; Kim, E.; Siddiqi, I.

    2016-10-01

    We present a systematic study of the effects of shielding on the internal quality factors ({Q}{{i}}) of Al and TiN microwave resonators designed for use in quantum coherent circuits. Measurements were performed in an adiabatic demagnetization refrigerator, where typical magnetic fields of 200 μT are present at the unshielded sample stage. Radiation shielding consisted of 100 and 500 mK Cu cans coated with infrared absorbing epoxy. Magnetic shields consisted of Cryoperm 10 and Sn plating of the Cu cans. A 2.7 K radiation can and coaxial thermalization filters were present in all measurements. TiN samples with {Q}{{i}}=1.3 × {10}6 at 100 mK exhibited no significant variation in quality factor when tested with limited shielding. In contrast, Al resonators showed improved {Q}{{i}} with successive shielding, with the largest gains obtained from the addition of the first radiation and magnetic shields and saturating before the addition of Sn plating infrared absorbing epoxy.

  12. Radiation Exposure Analyses Supporting the Development of Solar Particle Event Shielding Technologies

    Science.gov (United States)

    Walker, Steven A.; Clowdsley, Martha S.; Abston, H. Lee; Simon, Hatthew A.; Gallegos, Adam M.

    2013-01-01

    NASA has plans for long duration missions beyond low Earth orbit (LEO). Outside of LEO, large solar particle events (SPEs), which occur sporadically, can deliver a very large dose in a short amount of time. The relatively low proton energies make SPE shielding practical, and the possibility of the occurrence of a large event drives the need for SPE shielding for all deep space missions. The Advanced Exploration Systems (AES) RadWorks Storm Shelter Team was charged with developing minimal mass SPE storm shelter concepts for missions beyond LEO. The concepts developed included "wearable" shields, shelters that could be deployed at the onset of an event, and augmentations to the crew quarters. The radiation transport codes, human body models, and vehicle geometry tools contained in the On-Line Tool for the Assessment of Radiation In Space (OLTARIS) were used to evaluate the protection provided by each concept within a realistic space habitat and provide the concept designers with shield thickness requirements. Several different SPE models were utilized to examine the dependence of the shield requirements on the event spectrum. This paper describes the radiation analysis methods and the results of these analyses for several of the shielding concepts.

  13. Advanced Neutron Source Reactor zoning, shielding, and radiological optimization guide

    International Nuclear Information System (INIS)

    In the design of major nuclear facilities, it is important to protect both humans and equipment excessive radiation dose. Past experience has shown that it is very effective to apply dose reduction principles early in the design of a nuclear facility both to specific design features and to the manner of operation of the facility, where they can aid in making the facility more efficient and cost-effective. Since the appropriate choice of radiological controls and practices varies according to the case, each area of the facility must be analyzed for its radiological impact, both by itself and in interactions with other areas. For the Advanced Neutron Source (ANS) project, a large relational database will be used to collect facility information by system and relate it to areas. The database will also hold the facility dose and shielding information as it is produced during the design process. This report details how the ANS zoning scheme was established and how the calculation of doses and shielding are to be done

  14. Evaluation of Spacecraft Shielding Effectiveness for Radiation Protection

    Science.gov (United States)

    Cucinotta, Francis A.; Wilson, John W.

    1999-01-01

    The potential for serious health risks from solar particle events (SPE) and galactic cosmic rays (GCR) is a critical issue in the NASA strategic plan for the Human Exploration and Development of Space (HEDS). The excess cost to protect against the GCR and SPE due to current uncertainties in radiation transmission properties and cancer biology could be exceedingly large based on the excess launch costs to shield against uncertainties. The development of advanced shielding concepts is an important risk mitigation area with the potential to significantly reduce risk below conventional mission designs. A key issue in spacecraft material selection is the understanding of nuclear reactions on the transmission properties of materials. High-energy nuclear particles undergo nuclear reactions in passing through materials and tissue altering their composition and producing new radiation types. Spacecraft and planetary habitat designers can utilize radiation transport codes to identify optimal materials for lowering exposures and to optimize spacecraft design to reduce astronaut exposures. To reach these objectives will require providing design engineers with accurate data bases and computationally efficient software for describing the transmission properties of space radiation in materials. Our program will reduce the uncertainty in the transmission properties of space radiation by improving the theoretical description of nuclear reactions and radiation transport, and provide accurate physical descriptions of the track structure of microscopic energy deposition.

  15. ESTIMATION OF INDUCED CURRENTS IN THE SHIELDS OF ELECTRICAL POWER CABLES WITH XLPE INSULATION

    Directory of Open Access Journals (Sweden)

    I. V. Oleksyuk

    2015-01-01

    Full Text Available Electrical power cables with Cross-Linked Polyethylene Insulation (XLPE-insulation are currently utilized in projects of the electric-power supply systems of modern facilities. However, the higher costs, the incomplete design, installation and maintenance normativetechnical basis as well as certain constructional features of the XLPE-insulated cable lines hinder their large-scale implementation.The cables with XLPE insulation are mostly produced in a single-conductor core version being provided with a composite copper shield whose cross-section may vary while the electric conductor cross-section remains uniform. Earthing the cable shields on both sides causes the flow of electricity in them. The course of operational service of the XLPE-insulated cable lines revealed the following fact – the currents induced in the cable shields can run up to the levels commeasurable with those in the conductor-cores themselves. That, in its turn, leads to electrical safety-level reduction, cable lines failure, and economic losses. The currents induced in the shields may occur both in symmetric (normal and emergency and asymmetric operating modes of the power grid with values of the induced currents reaching 80 % of the conducting core currents. Many factors affect the level of the current induced in the shield: the midpoint conductor modes, the values of the core longitudinal currents in the normal and emergency operating modes, failure mode, the cross-section area of the shield, the cables mutual disposition, and the distance between them.The paper claims experimental existence conformation of the cable-shield current induced by that in the conductor-core and demonstrates its measured value. The author establishes that induction of dangerous currents in the cable shields demands elaboration of measures on reducing their level.

  16. An innovative method for on-power radiometry of end-shields of nuclear power plants

    International Nuclear Information System (INIS)

    Every lndian PHWR reactor calandria is sandwiched within a pair of shield on either side. These shields are perpendicular to the coaxial axis of calandria and are called end-shields. These provide shielding from leakage radiation from reactor core in escaping out to Fuelling Machine vault, thereby significantly reducing the dose rates in the vaults. This has got a direct impact on radiation field in accessible areas. By maintaining low dose rates in accessible areas, the individual and collective doses of radiation workers can be effectively controlled well within the stipulated limits. Thus, it is of utmost importance to ensure adequacy of shielding provided by end-shields. In this context, a limited radiometry exercise is executed after filling of end-shields with steel balls and prior to their installation at designated place. This exercise provides limited inputs along the periphery of end-shield due to limited strength of radiation source, its handling provisions and dose constraints to the individual. In order to ascertain an in-depth analysis of shielding adequacy on-power, different methodologies have been adopted and have certain limitation in precisely pinpointing the affected area/location besides limitation on number of locations that can be monitored at a single stretch. To overcome these important anomalies, a computer based setup has been indigenously designed. The setup essentially comprises of a radiation monitor with wide energy, measuring, temperature and humidity range; a custom designed 25 m long compatible cable with suitable connectors; a laptop with additional cooling arrangement; a configurable interfacing software; thermal shielding for the detector and tying/fixing provisions. The radiation monitor after being properly shielded for thermal impacts is installed on the head of Fuelling Machine. It is connected through long cable to a laptop kept at Fuelling Machine service area with due cooling provisions (as temperature in the area will

  17. Development of a Fault Analysis Algorithm for HTS Power Cable Using RTDS Considering Both Conducting and Shield Layers

    Science.gov (United States)

    Kim, J. H.; Park, C. H.; Park, M.; Yu, I. K.

    High Temperature Superconducting (HTS) power cable consists of a conducting layer and a shield layer for carrying the required current. Geometrically, the conducting and shield layers each have self inductance; and the mutual inductance exists between the conducting and shield layers. Therefore, the direction of the current of shield the layer is opposite that of the conducting layer current. The value of the shield layer current is over 95% of the conducting layer current at the steady state. However, if a fault current passes through an HTS power cable, the quench occurs in both the conducting and shield layers. After the quench, resistance appears, and the even self inductance values are not changed a great deal, but the mutual inductance value is directly affected. According to the above mentioned processes, the current distribution of the conducting and shield layers changes due to the fault current. In this paper, the authors describe the transient state analysis of a real manufactured HTS power model cable, considering both the conducting and the shield layers. The manufactured system is coupled with RTDS, in which a utility grid is composed and simulated. These results provide important data for the design of an HTS power cable.

  18. Criteria of material selection for ballistic shields in the context of chosen degenerated models

    Directory of Open Access Journals (Sweden)

    M. Kulisiewicz

    2008-12-01

    Full Text Available Purpose: The models come from complex rheological models that static and quasi-static loading analysis waspresented in the following publications. The main conception of the research is determination of the mechanicalproperties of ballistic shield materials with the use of the complex constitutive compounds.Design/methodology/approach: In the paper criteria of material selection for ballistic shields in the context ofchosen degenerated models are described.Findings: Based on the research in direction of the first phase analysis of the punching process the final resultgives designing criteria for the new effective ballistic shields. The results of the presenting analysis give specifictechnical solution in the context of material selection for the ballistic shields.Practical implications: The article exemplifies the importance of material selection that is responsible for thefirst punching phase. That data is necessary to design the optimal ballistic shields.Originality/value: The new conception based on degenerated model finds application in analysis of punchingprocess. Nevertheless application of the technical solution will be possible after the new material testingmethods are curried out (identification methodology in the dynamic conditions. This is the main goal in thenext step of the research.

  19. Characterization of dynamic loads on the LMFBR rotating shield

    International Nuclear Information System (INIS)

    The rotating shields structure is a potential weak point of some current designs of primary containment against postulated whole core explosions. The calculation of the effect of transient loads on this structure, resulting from such an explosion, is therefore important in developing a safety case. The transient loads are usually calculated by computer codes such as ASTARTE, SEURBNUK, REXCO or ICECO and the effect of these loads on the structure by a suitable finite element code. Such procedure can be lengthly and costly. The present paper proposed a procedure which allows the consequences of changes in the transient loads, resulting from design changes for example, to be quickly and simply gauged. The load-impulse method of characterizing dynamic response of a structural system is well established. Provided loads with a similar temporal variation are compared, it can be shown that the dynamic response depends on only two features of the load, an average load and a time intregrated load or impulse. The scope of this approach has been extended by Youngdahl who has shown, for structures which deform in a rigid-plastic manner, that complex laoding histories can be equated to a rectangular form of loading, in a precise manner for simple structures and in an approximate manner for more complicated structures. This paper proposes that the failure characteristics of the rotating shields for which extensive plastic deformation is involved, be calculated for rectangular type loadings. The complex transient loadings calculated for various explosions and various changes in the primary vessel design can then be reduced to an equivalent rectangular form and the consequencial response of the shields structure deduced. (orig.)

  20. Evaluation of neutron streaming and future shielding measurement plan in the prototype FBR Monju

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Kenji; Usami, Shin; Deshimaru, Takehide; Nakashima, Fumiaki [Japan Nuclear Cycle Development Institute, Tsuruga, Fukui (Japan)

    2000-03-01

    This paper describes the shielding measurements results in the reactor head access area (RHAA) and the primary heat transport system (PHTS) cells performed during the power raising test periods from February through December, 1995 in the prototype fast breeder reactor Monju. We confirmed that the measured values were well below the shielding design requirements in the RHAA and the PHTS cells and that the countermeasures against neutron streaming to the RHAA and the PHTS cells were very effective. Future measurements in order to obtain basic data for use in future FBR design are planned for the next period of operation. (author)

  1. Analytic Ballistic Performance Model of Whipple Shields

    Science.gov (United States)

    Miller, J. E.; Bjorkman, M. D.; Christiansen, E. L.; Ryan, S. J.

    2015-01-01

    The dual-wall, Whipple shield is the shield of choice for lightweight, long-duration flight. The shield uses an initial sacrificial wall to initiate fragmentation and melt an impacting threat that expands over a void before hitting a subsequent shield wall of a critical component. The key parameters to this type of shield are the rear wall and its mass which stops the debris, as well as the minimum shock wave strength generated by the threat particle impact of the sacrificial wall and the amount of room that is available for expansion. Ensuring the shock wave strength is sufficiently high to achieve large scale fragmentation/melt of the threat particle enables the expansion of the threat and reduces the momentum flux of the debris on the rear wall. Three key factors in the shock wave strength achieved are the thickness of the sacrificial wall relative to the characteristic dimension of the impacting particle, the density and material cohesion contrast of the sacrificial wall relative to the threat particle and the impact speed. The mass of the rear wall and the sacrificial wall are desirable to minimize for launch costs making it important to have an understanding of the effects of density contrast and impact speed. An analytic model is developed here, to describe the influence of these three key factors. In addition this paper develops a description of a fourth key parameter related to fragmentation and its role in establishing the onset of projectile expansion.

  2. Asphalt as biological shielding against fusion neutrons

    International Nuclear Information System (INIS)

    For fusion experiments, thick biological radiation protection shields are necessary due to the deep penetration capability of the 14 MeV neutrons. A (D,T) neutron generator with a moderate output of around 1012 n/sec requires a concrete shielding of a wall thickness of 2 meters laterally and at the top of an experimental assembly. The cost for this biological shield may exceed the cost for most of the equipment for a fusion and/or hybrid experimental installation. Particularly, in Saudi Arabia, asphalt is very cheap and available in bulk quantities. As it is rich in hydrogen and carbon, it is worthwhile to investigate its shielding potential against fusion neutron. In the present work different biological shield configurations of asphalt at the wall of the experimental cavity for a research program being undertaken in Saudi Arabia, are investigated. The experimental cavity is approximated by a sphere of 5 meters radius. The yield of the neutron generator is taken as 1012 - 14 MeV - neutron/sec

  3. Expression of progesterone metabolizing enzyme genes (AKR1C1, AKR1C2, AKR1C3, SRD5A1, SRD5A2) is altered in human breast carcinoma

    International Nuclear Information System (INIS)

    (20α-HSO), AKR1C2 (3α-HSO3) and AKR1C3 (3α-HSO2) is reduced in tumorous as compared to normal breast tissue. The changes in progesterone metabolizing enzyme expression levels help to explain the increases in mitogen/metastasis inducing 5αP and decreases in mitogen/metastasis inhibiting 3αHP progesterone metabolites found in breast tumor tissues. Understanding what causes these changes in expression could help in designing protocols to prevent or reverse the changes in progesterone metabolism associated with breast cancer

  4. Health Monitoring Design for Extra-Large Diameter Underwater Shield Tunnels%超大直径水下盾构隧道健康监测设计研究

    Institute of Scientific and Technical Information of China (English)

    舒恒; 吴树元; 李健; 郭小红

    2015-01-01

    Considering that an underwater shield tunnel with defects or affected by a disaster may result in heavy economic losses and harmful social impacts during operation due to complex geological conditions and the environments outside and inside the tunnel, and using the Nanjing Weisan Road river-crossing project as an example, this paper systematically discusses the composition of a health monitoring system. Included in this discussion are the following topics: the selection of monitoring items, the typical section, the acquisition and transmission system of the monitoring data, the central database subsystem, the safety pre-warning and comprehensive evaluation subsystems, and the software system for the user interface. The results show that the health monitoring system, integrated with sensor testing, computer techniques, remote intelligent control, damage detection, signal analysis and safety evaluations, has the advantages of advancement, rationality, practicability, compatibility and convenience.%水下盾构隧道所处地质条件、内外部环境较为复杂,若运营期发生病害或灾害,易造成重大的经济损失和不良的社会影响。文章以南京纬三路过江通道工程为例,基于数值模拟结果,对结构健康监测系统的组成、监测项目、监测仪器及典型断面的选取、监测数据采集及传输系统、中心数据库子系统、隧道结构安全预警与综合评估子系统和用户界面软件系统进行了系统论述。研究结果表明,隧道结构健康监测及管理系统采用传感测试、计算机技术、远程智能控制、损伤识别、信号分析和结构安全评估新技术,具有先进性、合理性、实用性、兼容性和方便性,可以为保障隧道运营期的结构安全提供重要依据。

  5. CYLSEC: A three dimensional shield evaluation code

    International Nuclear Information System (INIS)

    Existing point kernel gamma codes are either limited to simple geometry configurations or require rather cumbersome input. These codes also require the user to specify the mesh size used in integrating the kernel. This results in computational inefficiencies since it is difficult to establish criteria for choosing mesh size and because it is generally not possible to assure convergence without solving the problem more than once. The interactive program CYLSEC was recently developed to improve this situation. CYLSEC can be used to evaluate bulk or local shielding for radioactive components, to treat streaming problems and to calculate a variety of gamma ray response functions. It will accept three dimensional geometries that can be described in terms of orthogonal slabs, right cylinders and/or right parallelepipeds. While the problem geometry is specified in rectangular coordinates, the integration of the kernel is performed in spherical coordinates. This allows explicit integration over the radial variable, thus reducing the problem to a double integral. The integral mesh size varies and is internally determined such that a specified convergence criterion is met. CYLSEC is also designed to recognize and take advantage of any problem symmetry in order to maximize efficiency. Program input is through interactive routines that are self checking and permit the user to make corrections. A gamma ray data library is provided, however, alternate data may be specified if desired. Comparisons between CYLSEC and other point kernel codes (QAD, GRACE) show excellent agreement in results and demonstrate that CYLSEC requires significantly less CPU time. Comparisons with the discrete ordinates code ANISN also show good agreement. An additional attraction to CYLSEC is that it is suitable for conversion to mini or personal computers

  6. Intercalated graphite fiber composites as EMI shields in aerospace structures

    Science.gov (United States)

    Gaier, James R.

    1992-01-01

    The requirements for electromagnetic interference (EMI) shielding in aerospace structures are more complicated than those for ground structures because of their weight limitations. As a result, the best EMI shielding materials must combine low density, high strength, and high elastic modulus with high shielding ability. EMI shielding characteristics were calculated for shields formed from pristine and intercalated graphite fiber/epoxy composites and compare to preliminary experimental results for these materials and to the characteristics of shields made from aluminum. Calculations indicate that effective EMI shields could be fabricated from intercalated graphite composites which would have less than 12 percent of the mass of conventional aluminum shields, based on mechanical properties and shielding characteristics alone.

  7. Data of evolutionary structure change: 1C5QA-3BSQA [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1C5QA-3BSQA 1C5Q 3BSQ A A IVGGYTCGANTVPYQVSLNSG-YHFCGGSLINSQWVVSA...ALLSGNQLHCGGVLVNERWVLTAAHCKMNEYTVHLGSDTLGDRRA--QRIKASKSFRHPGYSTQTHVNDLMLVKLNSQARL...el> 0 1C5Q A 1C5QA...A 3BSQA ALLSGNQLHCGA 1C5QA VSWGS-GCAQK<

  8. Accelerator shielding experts meet at CERN

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Fifteen years after its first CERN edition, the Shielding Aspects of Accelerator, Targets and Irradiation Facility (SATIF) conference was held again here from 2-4 June. Now at its 10th edition, SATIF10 brought together experts from all over the world to discuss issues related to the shielding techniques. They set out the scene for an improved collaboration and discussed novel shielding solutions.   This was the most attended meeting of the series with more than 65 participants from 34 institutions and 14 countries. “We welcomed experts from many different laboratories around the world. We come from different contexts but we face similar problems. In this year’s session, among other things, we discussed ways for improving the effectiveness of calculations versus real data, as well as experimental solutions to investigate the damage that radiation produces on various materials and the electronics”, says Marco Silari, Chair of the conference and member of the DGS/RP gro...

  9. Calculated shielding factors for selected European houses

    International Nuclear Information System (INIS)

    Shielding factors for gamma radiation from activity deposited on structures and ground surfaces have been calculated with the computer model DEPSHIELD for single-family and multi-storey buildings in France, United Kingdom and Denmark. For all three countries it was found that the shielding factors for single-family houses are approximately a factor of 2 - 10 higher that those for buildings with five or more storeys. Away from doors and windows the shielding factors for French, British, and Danish single-family houses are in the range 0.03 - 0.1, 0.06 - 0.4, and 0.07 - 0.3, respectively. The uncertainties of the calculations are discussed and DEPSHIELD-results are compared with other methods as well as with experimental results. (author)

  10. Vehicle drive module having improved EMI shielding

    Science.gov (United States)

    Beihoff, Bruce C.; Kehl, Dennis L.; Gettelfinger, Lee A.; Kaishian, Steven C.; Phillips, Mark G.; Radosevich, Lawrence D.

    2006-11-28

    EMI shielding in an electric vehicle drive is provided for power electronics circuits and the like via a direct-mount reference plane support and shielding structure. The thermal support may receive one or more power electronic circuits. The support may aid in removing heat from the circuits through fluid circulating through the support. The support forms a shield from both external EMI/RFI and from interference generated by operation of the power electronic circuits. Features may be provided to permit and enhance connection of the circuitry to external circuitry, such as improved terminal configurations. Modular units may be assembled that may be coupled to electronic circuitry via plug-in arrangements or through interface with a backplane or similar mounting and interconnecting structures.

  11. Radiation safety shield for a syringe

    International Nuclear Information System (INIS)

    Safety apparatus for use in administering radioactive serums by a syringe, without endangering the health and safety of the medical operators is described. The apparatus consists of a sheath and a shield which can be retracted into the sheath to assay the radioactive serum in an assay well. The shield can be moved from the retracted position into an extended position when the serum is to be injected into the patient. To protect the operator, the shield can be constructed of tantalum or any like high density substance to attenuate the radiation, emanating from the radioactive serums contained in the syringe, from passing to the atmosphere. A lead glass window is provided so that the operator can determine the exact quantity of the radioactive serum which is contained in the syringe

  12. Pyrithione-based ruthenium complexes as inhibitors of aldo-keto reductase 1C enzymes and anticancer agents.

    Science.gov (United States)

    Kljun, Jakob; Anko, Maja; Traven, Katja; Sinreih, Maša; Pavlič, Renata; Peršič, Špela; Ude, Žiga; Codina, Elisa Esteve; Stojan, Jure; Lanišnik Rižner, Tea; Turel, Iztok

    2016-08-01

    Four ruthenium complexes of clinically used zinc ionophore pyrithione and its oxygen analog 2-hydroxypyridine N-oxide were prepared and evaluated as inhibitors of enzymes of the aldo-keto reductase subfamily 1C (AKR1C). A kinetic study assisted with docking simulations showed a mixed type of inhibition consisting of a fast reversible and a slow irreversible step in the case of both organometallic compounds 1A and 1B. Both compounds also showed a remarkable selectivity towards AKR1C1 and AKR1C3 which are targets for breast cancer drug design. The organoruthenium complex of ligand pyrithione as well as pyrithione itself also displayed toxicity on the hormone-dependent MCF-7 breast cancer cell line with EC50 values in the low micromolar range. PMID:27357845

  13. Experimental analysis of an MIM capacitor with a concave shield

    Institute of Scientific and Technical Information of China (English)

    Liu Lintao; Yu Mingyan; Wang Jinxiang

    2009-01-01

    A novel shielding scheme is developed by inserting a concave shield between a metal-insulator-metal (MIM) capacitor and the silicon substrate. Chip measurements reveal that the concave shield improves the quality factor by 11 % at 11.8 GHz and 14% at 18.8 GHz compared with an unshielded MIM capacitor. It also alleviates the effect on shunt capacitance between the bottom plate of the MIM capacitor and the shield layer. Moreover, because the concave shields simplify substrate modeling, a simple circuit model of the MIM capacitor with concave shield is presented for radio frequency applications.

  14. Compilation of the computing methods in radiation shielding

    International Nuclear Information System (INIS)

    In order to update the KAERI radiation shielding technology, the calculational shielding methods were surveyed throughly. Computer codes and data libraries for radiation shielding calculation were collected and some model calculations were carried out with them. So far the following materials were ensured for our future use: 23 shielding codes, 7 data libraries, 7 data processing codes and 11 peripheral shielding codes. All of these were compiled again for the CYBER-73 computer system, and will be widely used in shielding analysis of accelerators, shipping casks as well as nuclear power plant. (author)

  15. Novel Concepts for Radiation Shielding Materials

    Science.gov (United States)

    Oliva-Buisson, Yvette J.

    2014-01-01

    It is critical that safety factors be maximized with respect to long duration, extraterrestrial space flight. Any significant improvement in radiation protection will be critical in ensuring the safety of crew and hardware on such missions. The project goal is to study novel concepts for radiation shielding materials that can be used for long-duration space missions. As part of this project we will investigate the use of thin films for the evaluation of a containment system that can retain liquid hydrogen and provide the necessary hydrogen density for effective shielding.

  16. [Electromagnetic Shielding Alters Behaviour of Rats].

    Science.gov (United States)

    Temuryants, N A; Kostyuk, A S; Tumanyants, K N

    2015-01-01

    It has been found that long-term electromagnetic shielding (19 hours per day for 10 days) leads to an increase in the duration of passive swimming time in male rats, decrease the duration of active swimming in the "forced swim" test as well as decrease of libido. On the other hand animals kept under the "open field" conditions do not show significant deviations from their normal behavior. Therefore, one could conclude that moderate electromagnetic shielding causes a depression-like state in rats. PMID:26080600

  17. Mathematical modeling of the radiation dose received from photons passing over and through shielding walls in a PET/CT suite

    DEFF Research Database (Denmark)

    Fog, Lotte S; Cormack, John

    2010-01-01

    emissions, the dose from scatter over the barrier at waist height is relatively small but may have to be taken into account if the design dose limit is low. Shielding from floor to ceiling is probably not warranted in most instances for PET gamma emissions; in PET/CT installations, however, a thinner layer...... of shielding may need to extend to the ceiling of the imaging room to limit x-ray scatter over the wall from the CT unit.......Given that the financial cost of shielding PET/CT suites can be substantial, it has become increasingly important to be able to accurately assess the thickness of shielding required for barriers and whether it is necessary to extend such shielding all the way to the ceiling. The overall shielding...

  18. Shielding effectiveness of rectangular cavity made of a new shielding material and resonance suppression

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    New shielding material has become an alternative to traditional metal to shield boxes from electromagnetic interferences. This article introduces the theory of transmission line method to study the shield boxes made of a new sort of material, and then expands the fundamental formulas to deal with the cases of multiple holes and polarization with arbitrary angle. By means of genetic algorithms with the aid of a three dimensional simulation tool, the damping of electromagnetic resonances in enclosures is researched.The computation indicates that under resonant frequency, electromagnetic resonance results in low, even negative shielding coefficient; whereas, for the same areas, shielding effectiveness of a single hole is worse than that of multiple holes. Shielding coefficient varies when polarization angle increases, and the coupled field through the rectangular aperture with the long side parallel to the thin wire is much weaker than that with the long side vertical to the thin wire. By using the metallic-loss dielectric layer of optimized calculation on the internal surface of the cavity, the best result of resonance suppression has been realized with the same thickness of coating. Finally, according to the calculation result, suggestions for shielding are proposed.

  19. Decision-making methodology of optimal shielding materials by using fuzzy linear programming

    International Nuclear Information System (INIS)

    The main purpose of our studies are to select materials and determine the ratio of constituent materials as the first stage of optimum shielding design to suit the individual requirements of nuclear reactors, reprocessing facilities, casks for shipping spent fuel, etc. The parameters of the shield optimization are cost, space, weight and some shielding properties such as activation rates or individual irradiation and cooling time, and total dose rate for neutrons (including secondary gamma ray) and for primary gamma ray. Using conventional two-valued logic (i.e. crisp) approaches, huge combination calculations are needed to identify suitable materials for optimum shielding design. Also, re-computation is required for minor changes, as the approach does not react sensitively to the computation result. Present approach using a fuzzy linear programming method is much of the decision-making toward the satisfying solution might take place in fuzzy environment. And it can quickly and easily provide a guiding principle of optimal selection of shielding materials under the above-mentioned conditions. The possibility or reducing radiation effects by optimizing the ratio of constituent materials is investigated. (author)

  20. Mechanical stability of the LHC dipole-dipole 50-75K thermal shield interconnect "floating" expansion joint concept

    CERN Document Server

    Skoczen, Blazej

    1998-01-01

    The LHC dipole cryostats are equipped with thermal shields carrying super-insulation. A cold helium transfer line equipped with expansion joints is integrated into the shield carrying trays (aluminium profiles supported on three composite feet). The stainless steel (316 L) expansion joints compensate for thermal contraction/expansion of the aluminium panels as well as for their misalignment. Design of the LHC thermal shield interconnect is based on the "floating" expansion joint concept (distance between the supports is of around 5 m). The present paper is dedicated to the analysis of mechanical stability of this large span system working at room and at cryogenic temperatures.