WorldWideScience

Sample records for high power neutron

  1. First observations of power MOSFET burnout with high energy neutrons

    International Nuclear Information System (INIS)

    Oberg, D.L.; Wert, J.L.; Normand, E.; Majewski, P.P.; Wender, S.A.

    1996-01-01

    Single event burnout was seen in power MOSFETs exposed to high energy neutrons. Devices with rated voltage ≥400 volts exhibited burnout at substantially less than the rated voltage. Tests with high energy protons gave similar results. Burnout was also seen in limited tests with lower energy protons and neutrons. Correlations with heavy-ion data are discussed. Accelerator proton data gave favorable comparisons with burnout rates measured on the APEX spacecraft. Implications for burnout at lower altitudes are also discussed

  2. Intense neutron source: high-voltage power supply specifications

    International Nuclear Information System (INIS)

    Riedel, A.A.

    1980-08-01

    This report explains the need for and sets forth the electrical, mechanical and safety specifications for a high-voltage power supply to be used with the intense neutron source. It contains sufficient information for a supplier to bid on such a power supply

  3. Self-powered neutron detector of high sensitivity

    International Nuclear Information System (INIS)

    Brixy, H.; Spillekothen, H.G.; Benninghofen, G.; Serafin, N.

    1983-01-01

    A self-powered neutron detector is proposed, consisting of three concentrically arranged electrically conducting tubes; where the central one forms the emitter and the inner and outer ones form the collector and where the tubes are electrically insulated from each other by insulating material. The emitter consists of a material with a high absorption cross-section for thermal neutrons, particularly of gadolinium, and is provided with an auxiliary emitter layer on the inside or the outside. With suitable dimensions and material, the auxiliary emitter layer increases the yield of electrons. (orig./HP) [de

  4. Spallation Neutron Source High Power RF Installation and Commissioning Progress

    CERN Document Server

    McCarthy, Michael P; Bradley, Joseph T; Fuja, Ray E; Gurd, Pamela; Hardek, Thomas; Kang, Yoon W; Rees, Daniel; Roybal, William; Young, Karen A

    2005-01-01

    The Spallation Neutron Source (SNS) linac will provide a 1 GeV proton beam for injection into the accumulator ring. In the normal conducting (NC) section of this linac, the Radio Frequency Quadupole (RFQ) and six drift tube linac (DTL) tanks are powered by seven 2.5 MW, 402.5 MHz klystrons and the four coupled cavity linac (CCL) cavities are powered by four 5.0 MW, 805 MHz klystrons. Eighty-one 550 kW, 805 MHz klystrons each drive a single cavity in the superconducting (SC) section of the linac. The high power radio frequency (HPRF) equipment was specified and procured by LANL and tested before delivery to ensure a smooth transition from installation to commissioning. Installation of RF equipment to support klystron operation in the 350-meter long klystron gallery started in June 2002. The final klystron was set in place in September 2004. Presently, all RF stations have been installed and high power testing has been completed. This paper reviews the progression of the installation and testing of the HPRF Sys...

  5. Workshop: Research and development plans for high power spallation neutron testing at BNL

    International Nuclear Information System (INIS)

    1996-01-01

    This report consists of vugraphs from presentations at the meeting. The papers covered the following topics: (1) APS as a proton source; (2) target status for NSNS (National Spallation Neutron Source); (3) spallation neutron source in Japan; (4) liquid LiBi flow loop; and (5) research and development plans for high power tests at the AGS

  6. High power pulsed neutron source for electronuclear installation

    Energy Technology Data Exchange (ETDEWEB)

    Korenev, S.A.; Puzynin, I.V.; Samoilov, V.N.; Sissakian, A.N. [Joint Inst. for Nuclear Research, Dubna (Russian Federation)

    1997-09-01

    The pulsed neutron source based on the reaction T(d,n)He is described in this report. The source consists of pulsed a pulsed Arkad`ev-Marx generator and a vacuum diode with explosive ion emission. 9 refs., 3 figs.

  7. Prompt neutron decay constant estimation of RSG-GAS at high power noise experiment

    International Nuclear Information System (INIS)

    Jujuratisbela, U.; Kristedjo; Tukiran; Pinem, S.; Iman, J.; Puryono; Sanjaya, A.; Suwarno

    1998-01-01

    The determination of prompt neutron decay constant (α) of RGS-GAS by using low power noise experiment method at the equilibrium core indicated that the result is not good. The bad result was due to the small ratio of the noise signal to background which was caused by low detector efficiency or contaminated core after long time operation. To solve the problem is tried by using noise experiment technique at high power. The voltage output of neutron detectors at power of 5, 12, and 23 MW were connected to preamplifier and filter then to the Dynamic Signal Analyzer Version-2 and then the power spectral density of each channel of JKT04 and JKT03, the cut off frequency of each channel can be determined by using linear regression technique such that the prompt neutron decay constant can be estimated

  8. Self powered neutron detectors

    International Nuclear Information System (INIS)

    Passe, J.; Petitcolas, H.; Verdant, R.

    1975-01-01

    The self-powered neutron detectors (SPND) enable to measure continuously high fluxes of thermal neutrons. They are particularly suitable for power reactor cores because of their robustness. Description of two kinds of SPND's characterized by the electrical current production way is given here: the first SPND's which present a V, Ag or Rh emitter are sensitive enough but they offer a few minute delay time: the second SPND's which are depending on the gamma activation have a short delay time. The emitter is made of Co or Pt. In any case, the signal is linear with reaction rates. Finally, the applications are briefly repeated here: irradiation facility monitor in research reactors, and flux map and space instability control in power reactors [fr

  9. Self-powered neutron detector

    International Nuclear Information System (INIS)

    Goldstein, N.P.; Todt, W.H.

    1976-01-01

    A self-powered neutron detector is detailed wherein a thin conductive layer of low neutron cross section, high density material is disposed about an emitter core of material which spontaneously emits radiation on neutron capture. The high density material is absorptive of beta radiation emitted by decay of the emitter core activation product, but is substantially transmissive to the high average energy prompt electrons emitted by the emitter core material. (author)

  10. High-power liquid-lithium target prototype for accelerator-based boron neutron capture therapy.

    Science.gov (United States)

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Bisyakoev, M; Eliyahu, I; Feinberg, G; Hazenshprung, N; Kijel, D; Nagler, A; Silverman, I

    2011-12-01

    A prototype of a compact Liquid-Lithium Target (LiLiT), which will possibly constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals, was built. The LiLiT setup is presently being commissioned at Soreq Nuclear Research Center (SNRC). The liquid-lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power generated using a high-intensity proton beam (>10 kW), necessary for sufficient neutron flux. In off-line circulation tests, the liquid-lithium loop generated a stable lithium jet at high velocity, on a concave supporting wall; the concept will first be tested using a high-power electron beam impinging on the lithium jet. High intensity proton beam irradiation (1.91-2.5 MeV, 2-4 mA) will take place at Soreq Applied Research Accelerator Facility (SARAF) superconducting linear accelerator currently in construction at SNRC. Radiological risks due to the (7)Be produced in the reaction were studied and will be handled through a proper design, including a cold trap and appropriate shielding. A moderator/reflector assembly is planned according to a Monte Carlo simulation, to create a neutron spectrum and intensity maximally effective to the treatment and to reduce prompt gamma radiation dose risks. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Dense granular Flows: a conceptual design of high-power neutron source

    Directory of Open Access Journals (Sweden)

    Yang Lei

    2017-01-01

    Full Text Available A high-power neutron source system is very useful for multifunctional applications, such as material facilities for advanced nuclear power, space radiation studies, radiography and tomography. Here the idea of inclined dense granular flow is utilized and developed in a new conceptual design of a compact high-power target to produce a high-energy and high-flux neutron irradiation (the flux is up to 1015 n/cm2/s or even 1016. Comparing to the traditional solid and liquid heavy metal targets, this design has advantages in material choice, fluid stability, heat removal, etc. In this paper the natures of the granular flows in an inclined chute are investigated and preliminary experimental and numerical results are reported. Then the feasibility of this design is discussed.

  12. High-power liquid-lithium jet target for neutron production

    OpenAIRE

    Halfon, S.; Arenshtam, A.; Kijel, D.; Paul, M.; Berkovits, D.; Eliyahu, I.; Feinberg, G.; Friedman, M.; Hazenshprung, N.; Mardor, I.; Nagler, A.; Shimel, G.; Tessler, M.; Silverman, I.

    2013-01-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the 7Li(p,n)7Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy (BNCT). The liquid-lithium jet target acts both as ...

  13. CERN-group conceptual design of a fast neutron operated high power energy amplifier

    International Nuclear Information System (INIS)

    Rubbia, C.; Rubio, J.A.; Buono, S.

    1997-01-01

    The practical feasibility of an Energy Amplifier (EA) with power and power density which are comparable to the ones of the present generation of large PWR is discussed in this paper. This is only possible with fast neutrons. Schemes are described which offer a high gain, a large maximum power density and an extended burn-up, well in excess of 100 GW x d/t corresponding to about five years at full power operation with no intervention on the fuel core. The following topics are discussed: physics considerations and parameter definition, the accelerator complex, the energy amplifier unit, computer simulated operation, and fuel cycle closing

  14. CERN-group conceptual design of a fast neutron operated high power energy amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Rubbia, C; Rubio, J A [European Organization for Nuclear Research, CERN, Geneva (Switzerland); Buono, S [Laboratoire du Cyclotron, Nice (France); and others

    1997-11-01

    The practical feasibility of an Energy Amplifier (EA) with power and power density which are comparable to the ones of the present generation of large PWR is discussed in this paper. This is only possible with fast neutrons. Schemes are described which offer a high gain, a large maximum power density and an extended burn-up, well in excess of 100 GW x d/t corresponding to about five years at full power operation with no intervention on the fuel core. The following topics are discussed: physics considerations and parameter definition, the accelerator complex, the energy amplifier unit, computer simulated operation, and fuel cycle closing. 84 refs, figs, tabs.

  15. High-power liquid-lithium jet target for neutron production

    Science.gov (United States)

    Halfon, S.; Arenshtam, A.; Kijel, D.; Paul, M.; Berkovits, D.; Eliyahu, I.; Feinberg, G.; Friedman, M.; Hazenshprung, N.; Mardor, I.; Nagler, A.; Shimel, G.; Tessler, M.; Silverman, I.

    2013-12-01

    A compact liquid-lithium target (LiLiT) was built and tested with a high-power electron gun at the Soreq Nuclear Research Center. The lithium target, to be bombarded by the high-intensity proton beam of the Soreq Applied Research Accelerator Facility (SARAF), will constitute an intense source of neutrons produced by the 7Li(p,n)7Be reaction for nuclear astrophysics research and as a pilot setup for accelerator-based Boron Neutron Capture Therapy. The liquid-lithium jet target acts both as neutron-producing target and beam dump by removing the beam thermal power (>5 kW, >1 MW/cm3) with fast transport. The target was designed based on a thermal model, accompanied by a detailed calculation of the 7Li(p,n) neutron yield, energy distribution, and angular distribution. Liquid lithium is circulated through the target loop at ˜200 °C and generates a stable 1.5 mm-thick film flowing at a velocity up to 7 m/s onto a concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power areal densities of >4 kW/cm2 and volume power density of ˜2 MW/cm3 at a lithium flow of ˜4 m/s while maintaining stable temperature and vacuum conditions. The LiLiT setup is presently in online commissioning stage for high-intensity proton beam irradiation (1.91-2.5 MeV, 1-2 mA) at SARAF.

  16. Development of high sensitivity transimpedance amplifier module for self powered neutron detectors

    International Nuclear Information System (INIS)

    Khan, T.K.; Tamboli, P.K.; Antony, J.; Balasubramanian, R.; Agilandaeswari, K.; Pramanik, M.

    2010-01-01

    This paper describes design and development of a Transimpedance Amplifier for amplification of very low current from in core Self Powered Neutron Detectors (SPND). Measurement of neutron flux is very important for operation, control and protection of Nuclear Power Plant (NPP). SPND is used to measure Reactor incore flux/power. Based on sensitivity of emitter material used in SPND, pitch length and neutron flux (power level); the current output from SPND varies from few pA to few μA. The described amplifier is suitable to use for this current range. The amplifier provides a very high gain using a resistive T network feedback topology. The amplifier is designed in two stages using ultra low bias current FET OPAMPs. Design of Transimpedance amplifier is carefully done to include ultra low input bias current, low offset voltage and noise. The amplifier has in built test facility for calibration and on line test facility for measurement of insulation resistance (IR). The amplifier module has on board isolated DC-DC converter circuit complying MIL/STD/461C/D which generate isolated +/-15V and +12V supply to provide parameter to parameter ground isolation and independence among each module/signal.The output from the amplifier is 0V to 6V for 0 to 150%FP. The design is simulated in computer and amplifier used at TAPS-3 was modified as per new design and has been tested at TAPS-3 site. The amplifier performed satisfactorily. The results showed that the IR measurement technique adopted in the design can tolerate lower IR of SPND in existing design. (author)

  17. Self powered neutron detectors

    International Nuclear Information System (INIS)

    Gopalan, C.S.; Ramachandra Rao, M.N.; Ingale, A.D.

    1976-01-01

    Two types of self powered neutron detectors used for in-core flux measurements are described. The characteristics of the various detectors, with emitters Rh, V, Co, Py are presented. Details about the fabrication of these detectors are given. (A.K.)

  18. High energy neutron radiography

    International Nuclear Information System (INIS)

    Gavron, A.; Morley, K.; Morris, C.; Seestrom, S.; Ullmann, J.; Yates, G.; Zumbro, J.

    1996-01-01

    High-energy spallation neutron sources are now being considered in the US and elsewhere as a replacement for neutron beams produced by reactors. High-energy and high intensity neutron beams, produced by unmoderated spallation sources, open potential new vistas of neutron radiography. The authors discuss the basic advantages and disadvantages of high-energy neutron radiography, and consider some experimental results obtained at the Weapons Neutron Research (WNR) facility at Los Alamos

  19. Survey on neutron production by electron beam from high power CW electron linear accelerator

    International Nuclear Information System (INIS)

    Toyama, S.

    1999-04-01

    In Japan Nuclear Cycle Development Institute, the development of high current CW electron linear accelerator is in progress. It is possible for an accelerator to produce neutrons by means of a spallation and photo nuclear reactions. Application of neutron beam produced by bremsstrahlung is one of ways of the utilization for high current electron accelerator. It is actual that many electron linear accelerators which maximum energy is higher than a few hundreds MeV are used as neutron sources. In this report, an estimate of neutron production is evaluated for high current CW electron linear accelerator. The estimate is carried out by 10 MeV beam which is maximum energy limited from the regulation and rather low for neutron production. Therefore, the estimate is also done by 17 and 35 MeV beam which is possible to be accelerated. Beryllium is considered as a target for lower electron energy in addition to Lead target for higher energy, because Beryllium has low threshold energy for neutron production. The evaluation is carried out in account of the target thickness optimized by the radiation length and neutron cross section reducing the energy loss for both of electron and neutron, so as to get the maximum number of neutrons. The result of the calculations shows neutron numbers 1.9 x 10 10 , 6.1 x 10 13 and 4.8 x 10 13 (n/s), respectively, for 10, 17, and 35 MeV with low duty. The thermal removal from the target is one of critical points. The additional shielding and cooling system is necessary in order to endure radiation. A comparison with other facilities are also carried out. The estimate of neutron numbers suggests the possibility to be applied for neutron radiography and measurement of nuclear data by means of Lead spectrometer, for example. (author)

  20. Self-powered neutron detector

    International Nuclear Information System (INIS)

    Goldstein, N.P.; Todt, W.H.

    1974-01-01

    The invention relates a self-powered neutron detector comprising an emitting body, an insulating material surrounding said body, and a conducting outer cover, a power conductor connected to the emitting body and passing through the insulating material permitting to insert an ammeter between said emitting body and said cover. The invention is characterized in that said emitting body is surrounded by a thin conducting layer of small cross section for neutrons made of high density material said material being capable of absorbing the beta-radiations due to the degradation of the emitting body activating product, while transmitting the fast electrons of high average energy emitted by said emitting body. This can be applied to safety control devices required to provide a quick answer [fr

  1. Target development for the SINQ high-power neutron spallation source

    International Nuclear Information System (INIS)

    Wagner, Werner

    2002-01-01

    SINQ is a 1 MW class research spallation neutron source, driven by the PSI proton accelerator system. In terms of beam power, it is, by a large margin, the most powerful spallation neutron source currently in operation worldwide. As a consequence, target load levels prevail in SINQ which are beyond the realm of existing experience. Therefore, an extensive materials irradiation program (STIP) is currently underway which will help to select the proper structural material and make dependable life time estimates accounting for the real operating conditions that prevail in the facility. In parallel, both theoretical and experimental work is going on within the MEGAPIE (MEGAwatt Pilot Experiment) project, to develop a liquid lead-bismuth spallation target for a beam power level of 1MW

  2. Development and characterization of a high yield transportable pulsed neutron source with efficient and compact pulsed power system

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Rishi, E-mail: rishiv9@gmail.com, E-mail: rishiv@barc.gov.in; Mishra, Ekansh; Dhang, Prosenjit; Sagar, Karuna; Meena, Manraj; Shyam, Anurag [Energetics and Electromagnetics Division, Bhabha Atomic Research Centre Autonagar, Vishakapatnam 530012 (India)

    2016-09-15

    The results of characterization experiments carried out on a newly developed dense plasma focus device based intense pulsed neutron source with efficient and compact pulsed power system are reported. Its high current sealed pseudospark switch based low inductance capacitor bank with maximum stored energy of ∼10 kJ is segregated into four modules of ∼2.5 kJ each and it cumulatively delivers peak current in the range of 400 kA–600 kA (corresponding to charging voltage range of 14 kV–18 kV) in a quarter time period of ∼2 μs. The neutron yield performance of this device has been optimized by discretely varying deuterium filling gas pressure in the range of 6 mbar–11 mbar at ∼17 kV/550 kA discharge. At ∼7 kJ/8.5 mbar operation, the average neutron yield has been measured to be in the order of ∼4 × 10{sup 9} neutrons/pulse which is the highest ever reported neutron yield from a plasma focus device with the same stored energy. The average forward to radial anisotropy in neutron yield is found to be ∼2. The entire system is contained on a moveable trolley having dimensions 1.5 m × 1 m × 0.7 m and its operation and control (up to the distance of 25 m) are facilitated through optically isolated handheld remote console. The overall compactness of this system provides minimum proximity to small as well as large samples for irradiation. The major intended application objective of this high neutron yield dense plasma focus device development is to explore the feasibility of active neutron interrogation experiments by utilization of intense pulsed neutron sources.

  3. Measurement and analysis of turbulent liquid metal flow in a high-power spallation neutron source-EURISOL

    CERN Document Server

    Samec, K; Blumenfeld, L; Kharoua, C; Dementjevs, S; Milenkovic, R Z

    2011-01-01

    The European Isotope Separation On-Line (EURISOL) design study completed in 2009 examined means of producing exotic nuclei for fundamental research. One of the critical components identified in the study was a high-power neutron spallation source in which a target material is impacted by a proton beam producing neutrons by a process known as spallation. Due to the high heat power deposition, liquid metal, in this case mercury, is the only viable choice as target material. Complex issues arise from the use of liquid metal. It is characterised by an unusually low Prandtl number and a higher thermal expansivity than conventional fluids. The turbulence structure in LM is thereby affected and still an object of intense research, hampered in part by measurement difficulties. The use of Computational Fluid Dynamics (CFD) allowed a satisfactory design for the neutron source to be found rapidly with little iteration. However it was feared that the development of the boundary layer and associated turbulence would not b...

  4. Pressure and stress waves in a spallation neutron source mercury target generated by high-power proton pulses

    CERN Document Server

    Futakawa, M; Conrad, H; Stechemesser, H

    2000-01-01

    The international ASTE collaboration has performed a first series of measurements on a spallation neutron source target at the Alternating Gradient Synchrotron (AGS) in Brookhaven. The dynamic response of a liquid mercury target hit by high-power proton pulses of about 40 ns duration has been measured by a laser Doppler technique and compared with finite elements calculations using the ABAQUS code. It is shown that the calculation can describe the experimental results for at least the time interval up to 100 mu s after the pulse injection. Furthermore, it has been observed that piezoelectric pressure transducers cannot be applied in the high gamma-radiation field of a spallation target.

  5. Experimental demonstration of a compact epithermal neutron source based on a high power laser

    Science.gov (United States)

    Mirfayzi, S. R.; Alejo, A.; Ahmed, H.; Raspino, D.; Ansell, S.; Wilson, L. A.; Armstrong, C.; Butler, N. M. H.; Clarke, R. J.; Higginson, A.; Kelleher, J.; Murphy, C. D.; Notley, M.; Rusby, D. R.; Schooneveld, E.; Borghesi, M.; McKenna, P.; Rhodes, N. J.; Neely, D.; Brenner, C. M.; Kar, S.

    2017-07-01

    Epithermal neutrons from pulsed-spallation sources have revolutionised neutron science allowing scientists to acquire new insight into the structure and properties of matter. Here, we demonstrate that laser driven fast (˜MeV) neutrons can be efficiently moderated to epithermal energies with intrinsically short burst durations. In a proof-of-principle experiment using a 100 TW laser, a significant epithermal neutron flux of the order of 105 n/sr/pulse in the energy range of 0.5-300 eV was measured, produced by a compact moderator deployed downstream of the laser-driven fast neutron source. The moderator used in the campaign was specifically designed, by the help of MCNPX simulations, for an efficient and directional moderation of the fast neutron spectrum produced by a laser driven source.

  6. Neutron measurements at nuclear power reactors [55

    CERN Document Server

    Scherpelz, R I

    2002-01-01

    Staff from the Pacific Northwest National Laboratory (operated by Battelle Memorial Institute), have performed neutron measurements at a number of commercial nuclear power plants in the United States. Neutron radiation fields at light water reactor (LWR) power plants are typically characterized by low-energy distributions due to the presence of large amounts of scattering material such as water and concrete. These low-energy distributions make it difficult to accurately monitor personnel exposures, since most survey meters and dosimeters are calibrated to higher-energy fields such as those produced by bare or D sub 2 O-moderated sup 2 sup 5 sup 2 Cf sources. Commercial plants typically use thermoluminescent dosimeters in an albedo configuration for personnel dosimetry and survey meters based on a thermal-neutron detector inside a cylindrical or spherical moderator for dose rate assessment, so their methods of routine monitoring are highly dependent on the energy of the neutron fields. Battelle has participate...

  7. High-power electron beam tests of a liquid-lithium target and characterization study of (7)Li(p,n) near-threshold neutrons for accelerator-based boron neutron capture therapy.

    Science.gov (United States)

    Halfon, S; Paul, M; Arenshtam, A; Berkovits, D; Cohen, D; Eliyahu, I; Kijel, D; Mardor, I; Silverman, I

    2014-06-01

    A compact Liquid-Lithium Target (LiLiT) was built and tested with a high-power electron gun at Soreq Nuclear Research Center (SNRC). The target is intended to demonstrate liquid-lithium target capabilities to constitute an accelerator-based intense neutron source for Boron Neutron Capture Therapy (BNCT) in hospitals. The lithium target will produce neutrons through the (7)Li(p,n)(7)Be reaction and it will overcome the major problem of removing the thermal power >5kW generated by high-intensity proton beams, necessary for sufficient therapeutic neutron flux. In preliminary experiments liquid lithium was flown through the target loop and generated a stable jet on the concave supporting wall. Electron beam irradiation demonstrated that the liquid-lithium target can dissipate electron power densities of more than 4kW/cm(2) and volumetric power density around 2MW/cm(3) at a lithium flow of ~4m/s, while maintaining stable temperature and vacuum conditions. These power densities correspond to a narrow (σ=~2mm) 1.91MeV, 3mA proton beam. A high-intensity proton beam irradiation (1.91-2.5MeV, 2mA) is being commissioned at the SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator. In order to determine the conditions of LiLiT proton irradiation for BNCT and to tailor the neutron energy spectrum, a characterization of near threshold (~1.91MeV) (7)Li(p,n) neutrons is in progress based on Monte-Carlo (MCNP and Geant4) simulation and on low-intensity experiments with solid LiF targets. In-phantom dosimetry measurements are performed using special designed dosimeters based on CR-39 track detectors. © 2013 Elsevier Ltd. All rights reserved.

  8. High energy neutron dosimeter

    International Nuclear Information System (INIS)

    Rai, K.S.F.

    1994-01-01

    A device for measuring dose equivalents in neutron radiation fields is described. The device includes nested symmetrical hemispheres (forming spheres) of different neutron moderating materials that allow the measurement of dose equivalents from 0.025 eV to past 1 GeV. The layers of moderating material surround a spherical neutron counter. The neutron counter is connected by an electrical cable to an electrical sensing means which interprets the signal from the neutron counter in the center of the moderating spheres. The spherical shape of the device allows for accurate measurement of dose equivalents regardless of its positioning. 2 figures

  9. Neutron and gamma irradiation effects on power semiconductor switches

    Science.gov (United States)

    Schwarze, G. E.; Frasca, A. J.

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  10. Measurement of neutron sensitivity of self powered neutron detectors

    International Nuclear Information System (INIS)

    Mahant, A.K.; Yeshuraja, V.; Ghodke, Shobha

    2005-01-01

    Self powered neutron detectors (SPNDs ) will form the part of Reactor Instrumentation in the upcoming 500 MWe power reactors. ECIL has developed Vanadium and Cobalt SPNDs for NPCIL to be used in regulation and protection channels. Experimental determination of neutron sensitivity of the vanadium and cobalt Self Powered Neutron Detectors (SPNDs) was carried out in A-l location of Apsara reactor at BARC. The measurements involved determination of total detector signal, its various components and the thermal neutron flux at the detector location. The paper describes the experimental techniques used to measure various parameters required to evaluate the neutron sensitivity of the SPNDs and also the parameters required to ascertain the integrity of SPNDs. Neutron flux measurement was done by gold foil irradiation technique. The predominant signal component from the vanadium SPND is Ib the current due to activation of the vanadium emitter, it forms about 85% of the total signal. The other components I n,γ due to the capture gamma rays of 52 V and I externalγ produced by the external reactor gamma rays contribute about 10% and 5% respectively to the total signal. Whereas in the cobalt SPND the main signal component is due to the capture gamma rays of 60 Co and accounts for about the 95% of the total signal. Remaining 5% signal is due to external reactor gamma rays. (author)

  11. Cold neutron radiography using low power accelerator

    International Nuclear Information System (INIS)

    Kiyanagi, Yoshiaki; Iwasa, Hirokatu

    1993-01-01

    A cold neutron source which can be adopted at a low power accelerator was studied. Time-of-flight radiography using the cold neutron source was performed. It is suggested that time-of-flight cold neutron radiography has possibility to distinguish the materials more clearly than the traditional film method since large contrast differences can be obtained by using digital data of the neutron intensity at different energies from thermal to cold region. Material will be identified at the same time by this method. (author)

  12. High energy neutron generator

    International Nuclear Information System (INIS)

    Barjon, R.; Breynat, G.

    1987-01-01

    This patent describes a generator of fast neutrons only slightly contaminated by neutrons of energy less than 15 MeV, comprising a source of charged particles of energy equal to at least 15 MeV, a target made of lithium deuteride, and means for cooling the target. The target comprises at least two elements placed in series in the path of the charged particles and separated from each other, the thickness of each of the elements being selected as a function of the average energy of the charged particles emitted from the source and the energy of the fast neutrons to be generated such that neutrons of energy equal to at least 15 MeV are emitted in the forward direction in response to the bombardment of the target from behind by the charged particles. The target cooling means comprises means for circulating between and around the elements a gas which does not chemically react with lithium deuteride

  13. Neutron and gamma irradiation effects on power semiconductor switches

    International Nuclear Information System (INIS)

    Schwarze, G.E.; Frasca, A.J.

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN bipolar junction transistors (BJTs), and metal-oxide-semiconductor field effect transistors (MOSFETs)

  14. High power operation of the polyphase resonant converter modulator system for the spallation neutron source linear accelerator

    CERN Document Server

    Reass, W A; Baca, D M; Doss, J D; Gonzáles, J M; Gribble, R F; Trujillo, P G

    2003-01-01

    The spallation neutron source (SNS) is a new 1.4 MW average power beam, 1 GeV accelerator being built at Oak Ridge national laboratory. The accelerator requires 15 "long-pulse" converter-modulator stations each providing a maximum of 11 MW pulses with a 1.1 MW average power. Two variants of the converter-modulator are utilized, an 80 kV and a 140 kV design, the voltage dependant on the type of klystron load. The converter-modulator can be described as a resonant zero-voltage- switching polyphase boost inverter. As noted in Figure 1, each converter modulator derives its buss voltage from a standard 13.8 kV to 2100 Y (1.5 MVA) substation cast-core transformer. The substation also contains harmonic traps and filters to accommodate IEEE 519 and 141 regulations. Each substation is followed by an SCR preregulator to accommodate system voltage changes from no load to full load, in addition to providing a soft-start function. Energy storage and filtering is provided by special low inductance self-clearing metallized ...

  15. Self-powered neutron flux detector

    International Nuclear Information System (INIS)

    Kroon, J.

    1979-01-01

    A self-powered neutron flux detector having an emitter electrode, at least a major portion of which is, 95 Mo encased in a tubular collector electrode and separated therefrom by dielectric material. The 95 Mo emitter electrode has experimentally shown a 98% prompt response, is primarily sensitive to neutron flux, has adequate sensitivity and has low burn up. Preferably the emitter electrode is molybdenum which has been enriched 75% to 99% by weight with 95 Mo

  16. High power accelerator-based boron neutron capture with a liquid lithium target and new applications to treatment of infectious diseases

    Energy Technology Data Exchange (ETDEWEB)

    Halfon, S. [Soreq NRC, Yavne 81800 (Israel); Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel)], E-mail: halfon@phys.huji.ac.il; Paul, M. [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); Steinberg, D. [Biofilm Laboratory, Institute of Dental Sciences, Faculty of Dentistry, Hebrew University-Hadassah (Israel); Nagler, A.; Arenshtam, A.; Kijel, D. [Soreq NRC, Yavne 81800 (Israel); Polacheck, I. [Clinical Microbiology and Infectious Diseases, Hadassah-Hebrew University Medical Center (Israel); Srebnik, M. [Department of Medicinal Chemistry and Natural Products, School of Pharmacy, Hebrew University, Jerusalem 91120 (Israel)

    2009-07-15

    A new conceptual design for an accelerator-based boron neutron capture therapy (ABNCT) facility based on the high-current low-energy proton beam driven by the linear accelerator at SARAF (Soreq Applied Research Accelerator Facility) incident on a windowless forced-flow liquid-lithium target, is described. The liquid-lithium target, currently in construction at Soreq NRC, will produce a neutron field suitable for the BNCT treatment of deep-seated tumor tissues, through the reaction {sup 7}Li(p,n){sup 7}Be. The liquid-lithium target is designed to overcome the major problem of solid lithium targets, namely to sustain and dissipate the power deposited by the high-intensity proton beam. Together with diseases conventionally targeted by BNCT, we propose to study the application of our setup to a novel approach in treatment of diseases associated with bacterial infections and biofilms, e.g. inflammations on implants and prosthetic devices, cystic fibrosis, infectious kidney stones. Feasibility experiments evaluating the boron neutron capture effectiveness on bacteria annihilation are taking place at the Soreq nuclear reactor.

  17. Mitigation technologies for damage induced by pressure waves in high-power mercury spallation neutron sources (1). Material surface improvement

    International Nuclear Information System (INIS)

    Naoe, Takashi; Futakawa, Masatoshi; Wakui, Takashi; Kogawa, Hiroyuki; Shoubu, Takahisa; Takeuchi, Hirotsugu; Kawai, Masayoshi

    2008-01-01

    Liquid-mercury target systems for MW-class spallation neutron sources are being developed in the world. Proton beams will be used to induce the spallation reaction. At the moment the proton beam hits the target, pressure waves are generated in the mercury because of the abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall. Localized impacts by microjets and/or shock waves that are caused by cavitation bubble collapse impose pitting damage on the vessel wall. Bubble collapse behavior was observed by using a high-speed video camera, as well as simulated numerically. Localized impact due to cavitation bubble collapse was quantitatively estimated through comparison between numerical simulation and experiment. A novel surface treatment technique that consists of carburizing and nitriding processes was developed and the treatment condition was optimized to mitigate the pitting damage due to localized impacts. (author)

  18. High-speed motion neutron radiography

    International Nuclear Information System (INIS)

    Bossi, R.H.; Barton, J.P.; Robinson, A.H.

    1982-01-01

    A system has been developed to perform neutron radiographic analysis of dynamic events having a duration of several milliseconds. The system has been operated in the range of 2000 to 10,000 frames. Synchronization has provided high-speed motion neutron radiographs for evaluation of the firing cycles of 7.62-mm munition rounds within a thick steel rifle barrel. The system has also been used to demonstrate its ability to produce neutron radiographic movies of two-phase flow. The equipment includes a TRIGA reactor capable of pulsing to a peak power of 3000 MW, a neutron beam collimator, a scintillator neutron conversion screen coupled to an image intensifier, and a 16-mm high-speed movie camera. The peak neutron flux incident at the object position is about 4 X 10 11 n/cm 2 X s with a pulse, full-width at half-maximum, of 9 ms. Modulation transfer function techniques have been used to assist optimization of the system performance. Special studies have been performed on the scintillator conversion screens and on the effects of statistical limitations on information availability

  19. Self-powered neutron flux detector assembly

    International Nuclear Information System (INIS)

    Allan, C.J.; McIntyre, I.L.

    1980-01-01

    A self-powered neutron flux detector has both the central emitter electrode and its surrounding collector electrode made of inconel 600. The lead cables may also be made of inconel. Other nickel alloys, or iron, nickel, titamium, chromium, zirconium or their alloys may also be used for the electrodes

  20. Development of highly effective neutron shields and neutron absorbing materials

    International Nuclear Information System (INIS)

    Tsuda, K.; Matsuda, F.; Taniuchi, H.; Yuhara, T.; Iida, T.

    1993-01-01

    A wide range of materials, including polymers and hydrogen-occluded alloys that might be usable as the neutron shielding material were examined. And a wide range of materials, including aluminum alloys that might be usable as the neutron-absorbing material were examined. After screening, the candidate material was determined on the basis of evaluation regarding its adaptabilities as a high-performance neutron-shielding and neutron-absorbing material. This candidate material was manufactured for trial, after which material properties tests, neutron-shielding tests and neutron-absorbing tests were carried out on it. The specifications of this material were thus determined. This research has resulted in materials of good performance; a neutron-shielding material based on ethylene propylene rubber and titanium hydride, and a neutron-absorbing material based on aluminum and titanium hydride. (author)

  1. Characterization of hybrid self-powered neutron detector under neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Nakamichi, M. E-mail: masaru@oarai.jaeri.go.jp; Nagao, Y.; Yamamura, C.; Nakazawa, M.; Kawamura, H

    2000-11-01

    To evaluate the irradiation behaviour of a blanket mock-up on in-pile functional test, it is necessary to measure the neutron flux change in the in-pile mock-up by a neutron detector, such as the self-powered neutron detector (SPND). With its small-sized emitter, which has high sensitivity and fast response time, SPND is an indispensable tool in order to measure the local neutron flux change. In the case of an in-pile functional test, it is necessary that response time is less than 1s and ratio of SPND output current is more than 0.3 of output current of SPND with Rh emitter. Therefore, a hybrid SPND with high sensitivity and fast response time was developed. This hybrid SPND used a hybrid emitter, i.e. Co cladded Pt-13%R000.

  2. Characterization of hybrid self-powered neutron detector under neutron irradiation

    CERN Document Server

    Nakamichi, M; Yamamura, C; Nakazawa, M; Kawamura, H

    2000-01-01

    To evaluate the irradiation behaviour of a blanket mock-up on in-pile functional test, it is necessary to measure the neutron flux change in the in-pile mock-up by a neutron detector, such as the self-powered neutron detector (SPND). With its small-sized emitter, which has high sensitivity and fast response time, SPND is an indispensable tool in order to measure the local neutron flux change. In the case of an in-pile functional test, it is necessary that response time is less than 1s and ratio of SPND output current is more than 0.3 of output current of SPND with Rh emitter. Therefore, a hybrid SPND with high sensitivity and fast response time was developed. This hybrid SPND used a hybrid emitter, i.e. Co cladded Pt-13%Rh.

  3. Determination of the Jet Neutron Rate and Fusion Power using the Magnetic Proton Recoil Neutron Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Sjoestrand, Henrik

    2003-01-01

    In this thesis a new independent method has been developed to enable precise measurements of neutron yields and rates from fusion plasmas and thereby determining the fusion power and fusion energy. The new method, together with the associated diagnostics, can provide information of great importance to present and future high fusion yield experiments, such as the Joint European Torus (JET) tokamak and the International Thermonuclear Experiment Reactor (ITER). The method has been applied to data from high fusion rate experiments from the tritium campaign at JET. By using the count-rate from the Magnetic Proton Recoil (MPR) neutron spectrometer the number of neutrons in the spectrometer's line of sight has been calculated. To be able to do this, all relevant factors between the plasma and the instrument have been evaluated. The number of neutrons in the MPR line of sight has been related to the total number of produced neutrons in the plasma by using information on the neutron emission profile. The achieved results have been compared with other JET neutron diagnostic data and the agreement is shown to be very good.

  4. A study on the linearity characteristics of neutron power measurement system for Hanaro

    International Nuclear Information System (INIS)

    Kang, Tai Ki; Kim, Young Ki; Lee, Byung Chul; Park, Sang Jun

    1999-06-01

    It is briefly described the general principles of neutron detection and the method of neutron measurement in the nuclear reactor which neutron flux varies widely and gamma radiation also exists. Wide-range Fission Chamber System which is excellent in electrical and mechanical performances has been selected for neutron power measurement system for Hanaro. The linearity characteristics of neutron power signals is a critical factor of the reliability in reactor power control. In particular , the linearity of the log power signal, which covers 10 decade form 10 -8 %FP to 200 %FP was a matter of primary concern during commissioning. In case of the linear power signal for reactor control at high power condition, the output signals were additionally analyzed in connection with the reactor thermal power and the delayed neutron signal from the primary pipe as well as the output signal from the compensated ion chamber as a reference signal. (author). 13 refs., 7 tabs., 33 figs

  5. A study on the linearity characteristics of neutron power measurement system for Hanaro

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tai Ki; Kim, Young Ki; Lee, Byung Chul; Park, Sang Jun

    1999-06-01

    It is briefly described the general principles of neutron detection and the method of neutron measurement in the nuclear reactor which neutron flux varies widely and gamma radiation also exists. Wide-range Fission Chamber System which is excellent in electrical and mechanical performances has been selected for neutron power measurement system for Hanaro. The linearity characteristics of neutron power signals is a critical factor of the reliability in reactor power control. In particular , the linearity of the log power signal, which covers 10 decade form 10 {sup -8} %FP to 200 %FP was a matter of primary concern during commissioning. In case of the linear power signal for reactor control at high power condition, the output signals were additionally analyzed in connection with the reactor thermal power and the delayed neutron signal from the primary pipe as well asthe output signal from the compensated ion chamber as a reference signal. (author). 13 refs., 7 tabs., 33 figs.

  6. Self-powered neutron and gamma-ray flux detector

    International Nuclear Information System (INIS)

    Allan, C.J.; Shields, R.B.; Lynch, G.F.; Cuttler, J.M.

    1980-01-01

    A new type of self-powered neutron detector was developed which is sensitive to both the neutron and gamma-ray fluxes. The emitter comprises two parts. The central emitter core is made of materials that generate high-energy electrons on exposure to neutrons. The outer layer acts as a gamma-ray/electron converter, and since it has a higher atomic number and higher back-scattering coefficient than the collector, increases the net outflow or emmission of electrons. The collector, which is around the emitter outer layer, is insulated from the outer layer electrically with dielectric insulation formed from compressed metal-oxide powder. The fraction of electrons given off by the emitter that is reflected back by the collector is less than the fraction of electrons emitted by the collector that is reflected back by the emitter. The thickness of the outer layer needed to achieve this result is very small. A detector of this design responds to external reactor gamma-rays as well as to neutron capture gamma-rays from the collector. The emitter core is either nickel, iron or titanium, or alloys based on these metals. The outer layer is made of platinum, tantalum, osmium, molybdenum or cerium. The detector is particularly useful for monitoring neutron and gamma ray flux intensities in nuclear reactor cores in which the neutron and gamma ray flux intensities are closely proportional, are unltimately related to the fission rate, and are used as measurements of nuclear reactor power. (DN)

  7. Real time neutron flux monitoring using Rh self powered neutron detector

    International Nuclear Information System (INIS)

    Juna, Byung Jin; Lee, Byung Chul; Park, Sang Jun; Jung, Hoan Sung

    2012-01-01

    Rhodium (Rh) self powered neutron detectors (SPNDs) are widely used for on line monitoring of local neutron flux. Its signal is slower than the actual variation of neutron flux owing to a delayed β decay of the Rh activation product, but real time monitoring is possible by solving equations between the neutron reaction rate in the detector and its signal. While the measuring system is highly reliable, the accuracy depends on the method solving the equations and accuracy of the parameters in the equations. The uncertain parameters are the contribution of gamma rays to the signal, and the branching ratios of Rh 104 and Rh 104m after the neutron absorption of Rh 103. Real time neutron flux monitoring using Rh SPNDs has been quite successful for neutron transmutation doping (NTD) at HANARO. We revisited the initial data used for the verification of a real time monitoring system, to refine algorithm for a better solution and to check the parameters for correctness. As a result, we suggest an effective way to determine the prompt parameter

  8. Real time neutron flux monitoring using Rh self powered neutron detector

    Energy Technology Data Exchange (ETDEWEB)

    Juna, Byung Jin; Lee, Byung Chul; Park, Sang Jun; Jung, Hoan Sung [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    Rhodium (Rh) self powered neutron detectors (SPNDs) are widely used for on line monitoring of local neutron flux. Its signal is slower than the actual variation of neutron flux owing to a delayed {beta} decay of the Rh activation product, but real time monitoring is possible by solving equations between the neutron reaction rate in the detector and its signal. While the measuring system is highly reliable, the accuracy depends on the method solving the equations and accuracy of the parameters in the equations. The uncertain parameters are the contribution of gamma rays to the signal, and the branching ratios of Rh 104 and Rh 104m after the neutron absorption of Rh 103. Real time neutron flux monitoring using Rh SPNDs has been quite successful for neutron transmutation doping (NTD) at HANARO. We revisited the initial data used for the verification of a real time monitoring system, to refine algorithm for a better solution and to check the parameters for correctness. As a result, we suggest an effective way to determine the prompt parameter.

  9. Variation of Neutron Moderating Power on HDPE by Gamma Radiation

    International Nuclear Information System (INIS)

    Park, Kwang June; Ju, June Sik; Kang, Hee Young; Shin, Hee Sung; Kim, Ho Dong

    2009-01-01

    High density polyethylene (HDPE) is degraded due to a radiation-induced oxidation when it is used as a neutron moderator in a neutron counter for a nuclear material accounting of spent fuels. The HDPE exposed to the gamma-ray emitted from the fission products in a spent nuclear fuel results in a radiation-induced degradation which changes its original molecular structure to others. So a neutron moderating power variation of HDPE, irradiated by a gamma radiation, was investigated in this work. Five HDPE moderator structures were exposed to the gamma radiation emitted from a 60 Co source to a level of 10 5 -10 9 rad to compare their post-irradiation properties. As a result of the neutron measurement test with 5 irradiated HDPE structures and a neutron measuring system, it was confirmed that the neutron moderating power for the 105 rad irradiated HDPE moderator revealed the largest decrease when the un-irradiated pure one was used as a reference. It implies that a neutron moderating power variation of HDPE is not directly proportional to the integrated gamma dose rate. To clarify the cause of these changes, some techniques such as a FTIR, an element analysis and a densitometry were employed. As a result of these analyses, it was confirmed that the molecular structure of the gamma irradiated HDPEs had partially changed to others, and the contents of hydrogen and oxygen had varied during the process of a radiation-induced degradation. The mechanism of these changes cannot be explained in detail at present, and thus need further study

  10. High precision thermal neutron detectors

    Energy Technology Data Exchange (ETDEWEB)

    Radeka, V.; Schaknowski, N.A.; Smith, G.C.; Yu, B. [Brookhaven National Laboratory, Upton, NY (United States)

    1994-12-31

    Two-dimensional position sensitive detectors are indispensable in neutron diffraction experiments for determination of molecular and crystal structures in biology, solid-state physics and polymer chemistry. Some performance characteristics of these detectors are elementary and obvious, such as the position resolution, number of resolution elements, neutron detection efficiency, counting rate and sensitivity to gamma-ray background. High performance detectors are distinguished by more subtle characteristics such as the stability of the response (efficiency) versus position, stability of the recorded neutron positions, dynamic range, blooming or halo effects. While relatively few of them are needed around the world, these high performance devices are sophisticated and fairly complex, their development requires very specialized efforts. In this context, we describe here a program of detector development, based on {sup 3}He filled proportional chambers, which has been underway for some years at the Brookhaven National Laboratory. Fundamental approaches and practical considerations are outlined that have resulted in a series of high performance detectors with the best known position resolution, position stability, uniformity of response and reliability over time, for devices of this type.

  11. Neutron generator power supply modeling in EMMA

    International Nuclear Information System (INIS)

    Robinson, A.C.; Farnsworth, A.V.; Montgomery, S.T.; Peery, J.S.; Merewether, K.O.

    1996-01-01

    Sandia National Laboratories has prime responsibility for neutron generator design and manufacturing, and is committed to developing predictive tools for modeling neutron generator performance. An important aspect of understanding component performance is explosively driven ferroelectric power supply modeling. EMMA (ElectroMechanical Modeling in ALEGRA) is a three dimensional compile time version of Sandia's ALEGRA code. The code is built on top of the general ALEGRA framework for parallel shock-physics computations but also includes additional capability for modeling the electric potential field in dielectrics. The overall package includes shock propagation due to explosive detonation, depoling of ferroelectric ceramics, electric field calculation and coupling with a general lumped element circuit equation system. The AZTEC parallel iterative solver is used to solve for the electric potential. The DASPK differential algebraic equation package is used to solve the circuit equation system. Sample calculations are described

  12. 3D pin-by-pin power density profiles with high spatial resolution in the vicinity of a BWR control blade tip simulated with coupled neutronics/burn-up calculations

    International Nuclear Information System (INIS)

    Li, J.; Nünighoff, K.; Allelein, H.-J.

    2011-01-01

    Highlights: ► High spatial resolution neutronic and burn-up calculations of quarter BWR fuel element section. ► Coupled MCNP(X)–ORIGEN2.2 simulation using VESTA. ► Control blade history effect was taken into account. ► Determining local power excursion after instantaneous control rod movement. ► Correlation between control blade geometry and occurrence of local power excursions. - Abstract: Pellet cladding interaction (PCI) as well as pellet cladding mechanical interaction (PCMI) are well-known fuel failures in light water reactors, especially in boiling water reactors (BWR). Whereas the thermo-mechanical processes of PCI effects have been intensively investigated in the last decades, only rare information is available on the role of neutron physics. However, each power transient is primary due to neutron physics effects and thus knowledge of the neutron physical background is mandatory to better understand the occurrence of PCI effects in BWRs. This paper will focus on a study of local power excursions in a typical BWR fuel assembly during control rod movements. Burn-up and energy deposition were simulated with high spatial granularity, especially in the vicinity of the control blade tip. It could be shown, that the design of the control blade plays a dominant role for the occurrence of local power peaks while instantaneously moving down the control rod. The main result is, that the largest power peak occurs at the interface between steel handle and absorber rods. A full width half maximum (FWHM) of ±2.5 cm was observed. This means, the local power excursion due to neutron physics phenomena involve approximately five pellets. With the VESTA code coupled MCNP(X)/ORIGEN2.2 calculations were performed with more than 3400 burn-up zones in order to take history effects into account.

  13. Some properties of zero power neutron noise in a time-varying medium with delayed neutrons

    International Nuclear Information System (INIS)

    Kitamura, Y.; Pal, L.; Pazsit, I.; Yamamoto, A.; Yamane, Y.

    2008-01-01

    The temporal evolution of the distribution of the number of neutrons in a time-varying multiplying system, producing only prompt neutrons, was treated recently with the master equation technique by some of the present authors. Such a treatment gives account of both the so-called zero power reactor noise and the power reactor noise simultaneously. In particular, the first two moments of the neutron number, as well as the concept of criticality for time-varying systems, were investigated and discussed. The present paper extends these investigations to the case when delayed neutrons are also taken into account. Due to the complexity of the description, only the expectation of the neutron number is calculated. The concept of criticality of a time-varying system is also generalized to systems with delayed neutrons. The temporal behaviour of the expectation of the number of neutrons and its asymptotic properties are displayed and discussed

  14. Introduction to the neutron kinetics of nuclear power reactors

    CERN Document Server

    Tyror, J G; Grant, P J

    2013-01-01

    An Introduction to the Neutron Kinetics of Nuclear Power Reactors introduces the reader to the neutron kinetics of nuclear power reactors. Topics covered include the neutron physics of reactor kinetics, feedback effects, water-moderated reactors, fast reactors, and methods of plant control. The reactor transients following faults are also discussed, along with the use of computers in the study of power reactor kinetics. This book is comprised of eight chapters and begins with an overview of the reactor physics characteristics of a nuclear power reactor and their influence on system design and

  15. Comparison study on in-core neutron detector for online neutron flux mapping of research and power reactor

    International Nuclear Information System (INIS)

    Zareen Khan Abdul Jalil Khan; Mohd Idris Taib; Izhar Abu Husin; Nurfarhana Ayuni

    2010-01-01

    This paper presents the comparison study on In-Core neutron detector using for online flux mapping of Research and Power reactor. Technical description of in-core neutron also taken into consideration to identify the different characterization of neutron detector and describe on Self Power neutron detector (SPND) for online neutron flux mapping. Able to provide information on the neutron flux distribution and understand how in-core neutron detector are being used in nuclear power plant including to enable to state the principles of neutron detector. (author)

  16. High intensity TOF spectrometer for cold neutrons

    International Nuclear Information System (INIS)

    Maayouf, R.M.; Abd El-Kawy, A.; Habib, N.; Adib, M.; Hamouda, I.

    1984-01-01

    This work presents a neutron time-of-flight (TOF) spectrometer developed specially for total neutron cross-section measurements at neutron energies below 5 MeV and sample's temperature varying from the liquid nitrogen one and up to 500 0 K. The spectrometer is equipped by remote control unit, designed especially, in order to move the sample in and out of the beam during the experimental measurements. The spectrometer has proved to be useful for transmission measurements at neutron energies below 5 MeV. It has a reasonable energy resolution (4.4%) and high effect to background ratio (11.1) at 5 MeV

  17. Intercomparison of high energy neutron personnel dosimeters

    International Nuclear Information System (INIS)

    McDonald, J.C.; Akabani, G.; Loesch, R.M.

    1993-03-01

    An intercomparison of high-energy neutron personnel dosimeters was performed to evaluate the uniformity of the response characteristics of typical neutron dosimeters presently in use at US Department of Energy (DOE) accelerator facilities. It was necessary to perform an intercomparison because there are no national or international standards for high-energy neutron dosimetry. The testing that is presently under way for the Department of Energy Laboratory Accreditation Program (DOELAP) is limited to the use of neutron sources that range in energy from about 1 keV to 2 MeV. Therefore, the high-energy neutron dosimeters presently in use at DOE accelerator facilities are not being tested effectively. This intercomparison employed neutrons produced by the 9 Be(p,n) 9 B interaction at the University of Washington cyclotron, using 50-MeV protons. The resulting neutron energy spectrum extended to a maximum of approximately 50-MeV, with a mean energy of about 20-MeV. Intercomparison results for currently used dosimeters, including Nuclear Type A (NTA) film, thermoluminescent dosimeter (TLD)-albedo, and track-etch dosimeters (TEDs), indicated a wide variation in response to identical doses of high-energy neutrons. Results of this study will be discussed along with a description of plans for future work

  18. High efficiency focus neutron generator

    Science.gov (United States)

    Sadeghi, H.; Amrollahi, R.; Zare, M.; Fazelpour, S.

    2017-12-01

    In the present paper, the new idea to increase the neutron yield of plasma focus devices is investigated and the results are presented. Based on many studies, more than 90% of neutrons in plasma focus devices were produced by beam target interactions and only 10% of them were due to thermonuclear reactions. While propounding the new idea, the number of collisions between deuteron ions and deuterium gas atoms were increased remarkably well. The COMSOL Multiphysics 5.2 was used to study the given idea in the known 28 plasma focus devices. In this circumstance, the neutron yield of this system was also obtained and reported. Finally, it was found that in the ENEA device with 1 Hz working frequency, 1.1 × 109 and 1.1 × 1011 neutrons per second were produced by D-D and D-T reactions, respectively. In addition, in the NX2 device with 16 Hz working frequency, 1.34 × 1010 and 1.34 × 1012 neutrons per second were produced by D-D and D-T reactions, respectively. The results show that with regards to the sizes and energy of these devices, they can be used as the efficient neutron generators.

  19. Method and apparatus for determination of temperature, neutron absorption cross section and neutron moderating power

    Science.gov (United States)

    Vagelatos, Nicholas; Steinman, Donald K.; John, Joseph; Young, Jack C.

    1981-01-01

    A nuclear method and apparatus determines the temperature of a medium by injecting fast neutrons into the medium and detecting returning slow neutrons in three first energy ranges by producing three respective detection signals. The detection signals are combined to produce three derived indicia each systematically related to the population of slow neutrons returning from the medium in a respective one of three second energy ranges, specifically exclusively epithermal neutrons, exclusively substantially all thermal neutrons and exclusively a portion of the thermal neutron spectrum. The derived indicia are compared with calibration indicia similarly systematically related to the population of slow neutrons in the same three second energy ranges returning from similarly irradiated calibration media for which the relationships temperature, neutron absorption cross section and neutron moderating power to such calibration indicia are known. The comparison indicates the temperature at which the calibration indicia correspond to the derived indicia and consequently the temperature of the medium. The neutron absorption cross section and moderating power of the medium can be identified at the same time.

  20. Monte Carlo simulation of high-flux 14 MeV neutron source based on muon catalyzed fusion using a high-power 50 MW deuteron beam

    Energy Technology Data Exchange (ETDEWEB)

    Vecchi, M [ENEA, Bologna (Italy); Karmanov, F I [Inst. of Nuclear Power Engineering, Obninsk (Russian Federation); Latysheva, L N; Pshenichnov, I A [Russian Academy of Sciences, Moscow (Russian Federation). Inst. for Nuclear Research

    1997-12-31

    The results Monte Carlo simulations of an intense neutron source based on muon catalyzed fusion process are presented. A deuteron beam is directed onto a cylindrical carbon target, located in vacuum converter chamber with a strong solenoidal magnetic field. The produced pions and muons which originate from pion decay are guided along magnetic field to a DT-synthesizer. Pion production in the primary target is simulated by means of Intranuclear and Internuclear cascade codes developed in INR, Moscow, while pion and muon transport process is studied by using a Monte Carlo code originated at CERN. The main purpose of the work is to calculate the pion and muon utilization efficiency taking into account the pion absorption in the primary target as well as all other losses of pions and muons in the converter and DT-cell walls. Preliminary estimations demonstrate the possibility to reach the level of 1014 n/s/cm{sup 2} for the neutron flux. (J.U.). 3 tabs., 4 figs., 8 refs.

  1. The new high flux neutron source FRM-2 in Munich

    International Nuclear Information System (INIS)

    Roegler, H.J.; Wierheim, G.

    2002-01-01

    Quite some years ago in 1974 to be exact, the first consideration on a new neutron source started at the technical university of Munich (Germany). 27 years later the new high flux neutron source (FRM-2) was read for hot operation, now delayed by a refused approval for its third partial license by the federal government of Germany despite a wide support from the scientific community. FRM-2 is a tank-type research reactor cooled by water, moderated by heavy water and whose thermal power was limited to 20 MW maximum. The extreme compact core together with the applied inverse flux principle led to a neutron flux design value of 8.10 18 n/m 2 .s at the reflector peak. 10 beam tubes will allow an optimized use of the high neutron flux. A hot neutron source with graphite at about 2200 Celsius degrees and a cold neutron source with liquid D 2 at about 25 K will provide shifted energy spectra. The utilization of FRM-2 is many-fold: neutronography and tomography, medical irradiation, radio-nuclide production, doping of pure silicon, neutron activation analysis. (A.C.)

  2. Transient response of self-powered neutron detectors

    International Nuclear Information System (INIS)

    Boeck, H.; Gebureck, P.; Stegemann, D.

    The behaviour of self-powered neutron detectors with Co, Er, Hf and Pt emitters was investigated during reactor square wave and pulse operation. The detector's response was compared with the current of an excore ionization chamber. Characteristical deviations from linearity were observed with all detectors at fast reactor periods. The exact cause of these deviations is not yet fully understood but several possibilities for the nonlinear behaviour of self-powered neutron detectors are outlined. (author)

  3. Techniques in high pressure neutron scattering

    CERN Document Server

    Klotz, Stefan

    2013-01-01

    Drawing on the author's practical work from the last 20 years, Techniques in High Pressure Neutron Scattering is one of the first books to gather recent methods that allow neutron scattering well beyond 10 GPa. The author shows how neutron scattering has to be adapted to the pressure range and type of measurement.Suitable for both newcomers and experienced high pressure scientists and engineers, the book describes various solutions spanning two to three orders of magnitude in pressure that have emerged in the past three decades. Many engineering concepts are illustrated through examples of rea

  4. High resolution neutron spectroscopy for helium isotopes

    International Nuclear Information System (INIS)

    Abdel-Wahab, M.S.; Klages, H.O.; Schmalz, G.; Haesner, B.H.; Kecskemeti, J.; Schwarz, P.; Wilczynski, J.

    1992-01-01

    A high resolution fast neutron time-of-flight spectrometer is described, neutron time-of-flight spectra are taken using a specially designed TDC in connection to an on-line computer. The high time-of-flight resolution of 5 ps/m enabled the study of the total cross section of 4 He for neutrons near the 3/2 + resonance in the 5 He nucleus. The resonance parameters were determined by a single level Breit-Winger fit to the data. (orig.)

  5. Triple ion-beam studies of radiation damage effects in a 316LN austenitic alloy for a high power spallation neutron source

    International Nuclear Information System (INIS)

    Lee, E.H.; Rao, G.R.; Hunn, J.D.; Rice, P.M.; Lewis, M.B.; Cook, S.W.; Farrell, K.; Mansur, L.K.

    1997-09-01

    Austenitic 316LN alloy was ion-irradiated using the unique Triple Ion Beam Facility (TIF) at ORNL to investigate radiation damage effects relevant to spallation neutron sources. The TIF was used to simulate significant features of GeV proton irradiation effects in spallation neutron source target materials by producing displacement damage while simultaneously injecting helium and hydrogen at appropriately high gas/dpa ratios. Irradiations were carried out at 80, 200, and 350 C using 3.5 MeV Fe ++ , 360 keV He + , and 180 keV H + to accumulate 50 dpa by Fe, 10,000 appm of He, and 50,000 appm of H. Irradiations were also carried out at 200 C in single and dual ion beam modes. The specific ion energies were chosen to maximize the damage and the gas accumulation at a depth of ∼ 1 microm. Variations in microstructure and hardness of irradiated specimens were studied using transmission electron microscopy (TEM) and a nanoindentation technique, respectively. TEM investigation yielded varying damage defect microstructures, comprising black dots, faulted and unfaulted loops, and a high number density of fine bubbles (typically less than 1 nm in diameter). With increasing temperature, faulted loops had a tendency to unfault, and bubble microstructure changed from a bimodal size distribution to a unimodal distribution. Triple ion irradiations at the three temperatures resulted in similar increases in hardness of approximately a factor of two. Individually, Fe and He ions resulted in a similar magnitude of hardness increase, whereas H ions showed only a very small effect. The present study has yielded microstructural information relevant to spallation neutron source conditions and indicates that the most important concern may be radiation induced hardening and associated ductility loss

  6. Triple Ion-Beam Studies of Radiation Damage Effects in a 316LN Austenitic Alloy for a High Power Spallation Neutron Source

    International Nuclear Information System (INIS)

    Lee, E.H.

    2001-01-01

    Austenitic 316LN alloy was ion-irradiated using the unique Triple Ion Beam Facility (TIF) at ORNL to investigate radiation damage effects relevant to spallation neutron sources. The TIF was used to simulate significant features of GeV proton irradiation effects in spallation neutron source target materials by producing displacement damage while simultaneously injecting helium and hydrogen at appropriately high gas/dpa ratios. Irradiations were carried out at 80, 200, and 350 C using 3.5 MeV Fe 2 , 360 keV He + , and 180 keV H + to accumulate 50 dpa by Fe, 10,000 appm of He, and 50,000 appm of H. Irradiations were also carried out at 200 C in single and dual ion beam modes. The specific ion energies were chosen to maximize the damage and the gas accumulation at a depth of ∼ 1 microm. Variations in microstructure and hardness of irradiated specimens were studied using transmission electron microscopy (TEM) and a nanoindentation technique, respectively. TEM investigation yielded varying damage defect microstructures, comprising black dots, faulted and unfaulted loops, and a high number density of fine bubbles (typically less than 1 nm in diameter). With increasing temperature, faulted loops had a tendency to unfault, and bubble microstructure changed from a bimodal size distribution to a unimodal distribution. Triple ion irradiations at the three temperatures resulted in similar increases in hardness of approximately a factor of two. Individually, Fe and He ions resulted in a similar magnitude of hardness increase, whereas H ions showed only a very small effect. The present study has yielded microstructural information relevant to spallation neutron source conditions and indicates that the most important concern may be radiation induced hardening and associated ductility loss

  7. Free neutron-proton analyzing power at medium energies

    International Nuclear Information System (INIS)

    Newsom, C.R.

    1980-01-01

    In recent years, increasing efforts have been made to measure the nucleon-nucleon polarization parameters. To date, no free neutron-proton spin correlated parameters have been published in the energy range 500 to 800 MeV. Existing analyzing power data is of low precision and in most cases was obtained by quasi-free proton scattering. As a first step in determining the neutron-proton scattering matrix, the free neutron-proton analyzing power has been measured at the Los Alamos Physics Facility as a function of energy and angle. The experiment was performed by scattering a neutron beam from a polarized proton target. The neutron beam was generated by scattering 800 MeV protons from a Beryllium target and using the neutrons produced at 0 degrees. The incident energy ranged from 300 MeV to 800 MeV. The energy spread of the neutron beam made it possible to measure the analyzing power at different energies simultaneously. Angular distributions were taken from 60 to 170 degrees in the center of mass system (c.m.)

  8. High frame-rate neutron radiography of dynamic events

    International Nuclear Information System (INIS)

    Bossi, R.H.; Robinson, A.H.; Barton, J.P.

    1981-01-01

    A system has been developed to perform neutron radiographic analysis of dynamic events having a duration of several milliseconds. The system has been operated in the range of 2000 to 10,000 frames/second. Synchronization has provided high-speed-motion neutron radiographs for evaluation of the firing cycle of 7.62 mm munition rounds within a steel rifle barrel. The system has also been used to demonstrate the ability to produce neutron radiographic movies of two-phase flow. The equipment uses the Oregon State University TRIGA reactor capable of pulsing to 3000 MW peak power, a neutron beam collimator, a scintillator neutron conversion screen coupled to an image intensifier, and a 16 mm high speed movie camera. The peak neutron flux incident at the object position is approximately 4 x 10 11 n/cm 2 s with a pulse, full width at half maximum, of 9 ms. Special studies have been performed on the scintillator conversion screens and on the effects of statistical limitations on the image quality. Modulation transfer function analysis has been used to assist in the evaluation of the system performance

  9. High frame-rate neutron radiography of dynamic events

    International Nuclear Information System (INIS)

    Bossi, R.H.; Robinson, A.H.; Barton, J.P.

    1983-01-01

    A system has been developed to perform neutron radiographic analysis of dynamic events having a duration of several milliseconds. The system has been operated in the range of 2000 to 10,000 frames/second. Synchronization has provided high-speed-motion neutron radiographs for evaluation of the firing cycle of 7.62 mm munition rounds within a steel rifle barrel. The system has also been used to demonstrate the ability to produce neutron radiographic movies of two phase flow. The equipment uses the Oregon State University TRIGA reactor capable of pulsing to 3000 MW peak power, a neutron beam collimator, a scintillator neutron conversion screen coupled to an image intensifier, and a 16 mm high speed movie camera. The peak neutron flux incident at the object position is approximately 4 x 10 11 n/cm 2 s with a pulse, full width at half maximum, of 9 ms. Special studies have been performed on the scintillator conversion screens and on the effects of statistical limitations on the image quality. Modulation transfer function analysis has been used to assist in the evaluation of the system performance. (Auth.)

  10. In-core neutron flux measurements at PARR using self powered neutron detector

    International Nuclear Information System (INIS)

    Hussain, A.; Ansari, S.A.

    1989-10-01

    This report describes experimental reactor physics measure ments at PARR using the in-core neutron detectors. Rhodium self powered neutron detectors (SPND) were used in the PARR core and several measurements were made aimed at detector calibration, response time determination and neutron flux measurements. The detectors were calibrated at low power using gold foils and full power by the thermal channel. Based on this calibration it was observed that the detector response remains almost linear throughout the power range. The self powered detectors were used for on-line determination of absolute neutron flux in the core as well as the spatial distribution of neutron flux or reactor power. The experimental, axial and horizontal flux mapping results at certain locations in the core are presented. The total response time of rhodium detector was experimentally determined to be about 5 minutes, which agree well with the theoretical results. Because of longer response time of SPND of the detectors it is not possible to use them in the reactor protection system. (author). 10 figs

  11. Neutron Scattering and High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Winn, Barry L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Stone, Matthew B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-11-01

    The workshop “Neutron Scattering and High Magnetic Fields” was held September 4-5, 2014 at the Oak Ridge National Laboratory (ORNL). The workshop was held in response to a recent report by the National Research Council of the National Academy of Sciences entitled “High Magnetic Field Science and Its Application in the United States: Current Status and Future Directions.”1 This report highlights the fact that neutron scattering measurements carried out in high magnetic fields provide important opportunities for new science. The workshop explored the range of the scientific discoveries that could be enabled with neutron scattering measurements at high fields (25 Tesla or larger), the various technologies that might be utilized to build specialized instruments and sample environment equipment to enable this research at ORNL, and possible routes to funding and constructing these facilities and portable high field sample environments.

  12. About possibility of creation of ecologically pure, safe nuclear power plants on the basis of high-effective resonant neutron interaction with splitting substances

    International Nuclear Information System (INIS)

    Irdyncheyev, L.A.; Malofeyev, A.M.; Frid, E.S.; Abramov, E.P.

    1993-01-01

    Currently the most important problem in nuclear engineering is creation of ecologically pure, safe nuclear power plants in the context of real danger of global ecological pollution of the environment with long-lived fission products and the resultant transuranium nuclides. The problem can be solved by creating nuclear power plants on the basis of high-effective resonant interaction (HERI). Such power plants would provide the total cycle, including nuclear fuel production (Plutonium-239 from Uranium-238), combustion and waste products salvaging by way of transformation of radioactive nuclides into stable isotopes

  13. Improved cable compensation technique for self powered neutron detectors

    International Nuclear Information System (INIS)

    Nieuwenhove, R. van

    1996-01-01

    Measurements with cobalt self powered neutron detectors on the BR2 reactor have revealed that the currents induced by external gamma radiation can be of the same order as the neutron induced signal and that the gamma induced current on the emitter and the compensator wires are not symmetric. In this case, the standard detection electronic setup leads to erroneous results. It is shown that a slightly modified electronic setup, in which this asymmetry is compensated for, can nevertheless allow to obtain correct neutron flux measurements. Measures to reduce the influence of external gamma radiation in general will also be discussed. (orig.)

  14. Applications of neutron radiography for the nuclear power industry

    Energy Technology Data Exchange (ETDEWEB)

    Craft, Aaron E.; Barton, John P.

    2016-11-01

    The World Conference on Neutron Radiography (WCNR) and International Topical Meeting on Neutron Radiography (ITMNR) series have been running over 35 years. The most recent event, ITMNR-8, focused on industrial applications and was the first time this series was hosted in China. In China, more than twenty new nuclear power plants are in construction and plans have been announced to increase the nuclear capacity further by a factor of three within fifteen years. There are additional prospects in many other nations. Neutron tests were vital during previous developments of materials and components for nuclear power applications, as reported in this conference series. For example a majority of the 140 papers in the Proceedings of the First WCNR are for the benefit of the nuclear power industry. Included are reviews of the diverse techniques being applied in Europe, Japan, the United States, and at many other centers. Many of those techniques are being utilized and advanced to the present time. Neutron radiography of irradiated nuclear fuel provides more comprehensive information about the internal condition of irradiated nuclear fuel than any other non-destructive technique to date. Applications include examination of nuclear waste, nuclear fuels, cladding, control elements, and other critical components. In this paper, the techniques developed and applied internationally for the nuclear power industry since the earliest years are reviewed, and the question is asked whether neutron test techniques can be of value in development of the present and future generations of nuclear power plants world-wide.

  15. Very High Energy Neutron Scattering from Hydrogen

    International Nuclear Information System (INIS)

    Cowley, R A; Stock, C; Bennington, S M; Taylor, J; Gidopoulos, N I

    2010-01-01

    The neutron scattering from hydrogen in polythene has been measured with the direct time-of flight spectrometer, MARI, at the ISIS facility of the Rutherford Appleton Laboratory with incident neutron energies between 0.5 eV and 600 eV. The results of experiments using the spectrometer, VESUVIO, have given intensities from hydrogen containing materials that were about 60% of the intensity expected from hydrogen. Since VESUVIO is the only instrument in the world that routinely operates with incident neutron energies in the eV range we have chosen to measure the scattering from hydrogen at high incident neutron energies with a different type of instrument. The MARI, direct time-of-flight, instrument was chosen for the experiment and we have studied the scattering for several different incident neutron energies. We have learnt how to subtract the gamma ray background, how to calibrate the incident energy and how to convert the spectra to an energy plot . The intensity of the hydrogen scattering was independent of the scattering angle for scattering angles from about 5 degrees up to 70 degrees for at least 3 different incident neutron energies between 20 eV and 100 eV. When the data was put on an absolute scale, by measuring the scattering from 5 metal foils with known thicknesses under the same conditions we found that the absolute intensity of the scattering from the hydrogen was in agreement with that expected to an accuracy of ± 5.0% over a wide range of wave-vector transfers between 1 and 250 A -1 . These measurements show that it is possible to measure the neutron scattering with incident neutron energies up to at least 100 eV with a direct geometry time-of-flight spectrometer and that the results are in agreement with conventional scattering theory.

  16. Self-Powered Neutron and Gamma Detectors for In-Core Measurements

    International Nuclear Information System (INIS)

    Strindehag, O.

    1971-11-01

    The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

  17. Self-Powered Neutron and Gamma Detectors for In-Core Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Strindehag, O

    1971-11-15

    The performance of various types of self-powered neutron and gamma detectors intended for control and power distribution measurements in water cooled reactors is discussed. The self-powered detectors are compared with other types of in-core detectors and attention is paid to such properties as neutron and gamma sensitivity, high-temperature performance, burn-up rate and time of response. Also treated are the advantages and disadvantages of using gamma detector data for power distribution calculations instead of data from neutron detectors. With regard to neutron-sensitive detectors, results from several long-term experiments with vanadium and cobalt detectors are presented. The results include reliability and stability data for these two detector types and the Co build-up in cobalt detectors. Experimental results which reveal the fast response of cobalt detectors are presented, and the use of cobalt detectors in reactor safety systems is discussed. Experience of the design and installation of complete flux probes, electronic units and data processing systems for power reactors is reported. The investigation of gamma-sensitive detectors includes detectors with emitters of lead, zirconium, magnesium and Inconel. Measured gamma sensitivities from calibrations both in a reactor and in a gamma cell are given, and the signal levels of self-powered neutron and gamma detectors when applied to power reactors are compared

  18. High precision neutron polarization for PERC

    International Nuclear Information System (INIS)

    Klauser, C.

    2013-01-01

    The decay of the free neutron into a proton, an electron and an anti-electron neutrino offers a simple system to study the semi-leptonic weak decay. High precision measurements of angular correlation coefficients of this decay provide the opportunity to test the standard model on the low energy frontier. The Proton Electron Radiation Channel PERC is part of a new generation of expriments pushing the accuracy of such an angular correlation coefficient measurement towards 10 -4 . Past experiments have been limited to an accuracy of 10 -3 with uncertainties on the neutron polarization as one of the leading systematic errors. This thesis focuses on the development of a stable, highly precise neutron polarization for a large, divergent cold neutron beam. A diagnostic tool that provides polarization higher than 99.99 % and analyzes with an accuracy of 10 -4 , the Opaque Test Bench, is presented and validated. It consists of two highly opaque polarized helium cells. The Opaque Test Bench reveals depolarizing effects in polarizing supermirrors commonly used for polarization in neutron decay experiments. These effects are investigated in detail. They are due to imperfect lateral magnetization in supermirror layers and can be minimized by significantly increased magnetizing fields and low incidence angle and supermirror factor m. A subsequent test in the crossed (X-SM) geometry demonstrated polarizations up to 99.97% from supermirrors only, improving neutron polarization with supermirrors by an order of magnitude. The thesis also discusses other neutron optical components of the PERC beamline: Monte-Carlo simulations of the beamline under consideration of the primary guide are carried out. In addition, calculation shows that PERC would statistically profit from an installation at the European Spallation source. Furthermore, beamline components were tested. A radio-frequency spin flipper was confirmed to work with an efficiency higher than 0.9999. (author) [de

  19. Design of auto-control high-voltage control system of pulsed neutron generator

    International Nuclear Information System (INIS)

    Lv Juntao

    2008-01-01

    It is difficult to produce multiple anode controlling time sequences under different logging mode for the high-voltage control system of the conventional pulsed neutron generator. It is also difficult realize sequential control among anode high-voltage, filament power supply and target voltage to make neutron yield stable. To these problems, an auto-control high-voltage system of neutron pulsed generator was designed. It not only can achieve anode high-voltage double blast time sequences, which can measure multiple neutron blast time sequences such as Σ, activated spectrum, etc. under inelastic scattering mode, but also can realize neutron generator real-time measurement of multi-state parameters and auto-control such as target voltage pulse width modulation (PWM), filament current, anode current, etc., there by it can produce stable neutron yield and realize stable and accurate measurement of the pulsed neutron full spectral loging tool. (authors)

  20. The new generations of power components will depend on neutron and/or electron bombardment techniques

    International Nuclear Information System (INIS)

    Lilen, H.

    1976-01-01

    Neutron and electron bombardment techniques for materials doping, newly introduced in the fabrication of power semiconductor components: diodes, transistors, thyristors, and triacs are briefly outlined. A neutron bombardment of high purity silicon results in a short-lived 31 Si isotope (from 30 Si) decaying into 31 P. The phosphorus with its five peripheral electrons induces a negative doping (N), and the neutron technique gives a homogeneous doping. Furthermore, silicon bombardment with 1 to 2MeV electrons induces micro-ruptures in the lattice, that act as recombination traps reducing carrier lifetimes. Consequently, gold diffusion techniques can be replaced by electron bombardment with a gain in controlling carrier lifetimes [fr

  1. Fusion Power Measurement Using a Combined Neutron Spectrometer-Camera System at ITER

    International Nuclear Information System (INIS)

    Sjoestrand, Henrik; Sunden, E. Andersson; Conroy, S.; Ericsson, G.; Johnson, M. Gatu; Giacomelli, L.; Hellesen, C.; Hjalmarsson, A.; Ronchi, E.; Weiszflog, M.; Kaellne, J.

    2008-01-01

    A central task for fusion plasma diagnostics is to measure the 2.5 and 14 MeV neutron emission rate in order to determine the fusion power. A new method for determining the neutron yield has been developed at JET. It makes use of the magnetic proton recoil neutron spectrometer and a neutron camera and provides the neutron yield with small systematic errors. At ITER a similar system could operate if a high-resolution, high-performance neutron spectrometer similar to the MPR was installed. In this paper, we present how such system could be implemented and how well it would perform under different assumption of plasma scenarios and diagnostic capabilities. It is found that the systematic uncertainty for using such a system as an absolute calibration reference is as low as 3% and hence it would be an excellent candidate for the calibration of neutron monitors such as fission chambers. It is also shown that the system could provide a 1 ms time resolved estimation of the neutron rate with a total uncertainty of 5%

  2. CSTI High Capacity Power

    International Nuclear Information System (INIS)

    Winter, J.M.

    1989-01-01

    The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil application. During FY-86 and 87, the NASA SP-100 Advanced Technology Program was devised to maintain the momentum of promising technology advancement efforts started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In FY-88, the Advanced Technology Program was incorporated into NASA's new Civil Space Technology Initiative (CSTI). The CSTI Program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA SP-100 Advanced Technology project, and provides a bridge to NASA Project Pathfinder. The elements of CSTI High Capacity Power development include Conversion Systems, Thermal Management, Power Management, System Diagnostics, and Environmental Interactions. Technology advancement in all areas, including materials, is required to assure the high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems as well as allowing mission independence from solar and orbital attitude requirements. Several recent advancements in CSTI High Capacity power development will be discussed

  3. Use of the Power Burst Facility for boron neutron capture therapy

    International Nuclear Information System (INIS)

    Crocker, J.G.; Griebenow, M.L.; Leatham, J.

    1990-01-01

    A program is under development at the Idaho National Engineering Laboratory (INEL) that involves using the Power Burst Facility (PBF) for research into boron neutron capture therapy (BNCT). BNCT utilizes the ionizing energy from boron-neutron capture to stop reproduction of or destroy cells in cancerous tissue in a two-step process. The first step is to selectively concentrate a boron isotope within the tumor cell, that when activated by neutron capture emits highly ionizing, short range particles. The second step involves activation of the isotope only in the vicinity of the tumor with a narrow neutron beam. The ( 10 B[n, 4 He] 7 Li) reaction with thermal neutrons produces fission products with track lengths approximately equal to a cell diameter. The INEL program includes the modification of the PBF by the addition of a filter and treatment area. The filter will down-scatter high energy neutrons into the epithermal range and remove thermal neutrons and excessively damaging gamma components. The intense source of epithermal neutrons from PBF is considered necessary to achieve optimum therapy for deep-seated tumors with minimum damage to surface tissue. THe neutron filter conceptualized for PBF utilizes aluminum and heavy water to down-scatter neutrons into the proper energy range. Bismuth will be used for gamma shielding and cadmium will remove the thermal neutron contaminant from the beam. The INEL program leads to human clinical trials at PBF which are intended to prove that brain tumors can be successfully treated through noninvasive techniques. Further research into BNCT at PBF for other cancer types is also anticipated

  4. High energy radiation from neutron stars

    International Nuclear Information System (INIS)

    Ruderman, M.

    1985-04-01

    Topics covered include young rapidly spinning pulsars; static gaps in outer magnetospheres; dynamic gaps in pulsar outer magnetospheres; pulse structure of energetic radiation sustained by outer gap pair production; outer gap radiation, Crab pulsar; outer gap radiation, the Vela pulsar; radioemission; and high energy radiation during the accretion spin-up of older neutron stars. 26 refs., 10 figs

  5. Neutron energy spectra calculations in the low power research reactor

    International Nuclear Information System (INIS)

    Omar, H.; Khattab, K.; Ghazi, N.

    2011-01-01

    The neutron energy spectra have been calculated in the fuel region, inner and outer irradiation sites of the zero power research reactor using the MCNP-4C code and the combination of the WIMS-D/4 transport code for generation of group constants and the three-dimensional CITATION diffusion code for core analysis calculations. The neutron energy spectrum has been divided into three regions and compared with the proposed empirical correlations. The calculated thermal and fast neutron fluxes in the low power research reactor MNSR inner and outer irradiation sites have been compared with the measured results. Better agreements have been noticed between the calculated and measured results using the MCNP code than those obtained by the CITATION code. (author)

  6. Real time neutronic evolution CNE (Embalse nuclear power plant)

    International Nuclear Information System (INIS)

    Notari, C.; Waldman, R.M.

    1993-01-01

    The simulator of the Embalse nuclear power plant uses a Point Reactor Model(PRM) for the neutronic evolution calculation. As this model is not conservative for transients produced by the sudden or localized reactivity insertion in big cores, it is convenient to use spatial models in these cases. In this report we show the results obtained using a nodal model (codes NODOS-TIEMPO). This model has been fitted against a more exact solution for the neutron flux and delayed neutron precursors. This has been done for the reactor at full power with nominal values for the reactivity control devices (liquid zones and adjusters rods). Transients corresponding to the global variation of the liquid zones and to the insertion of fresh fuel in some channels are shown. The results are compared with calculations made with the quasi-static model of the PUMA code. (author). 1 ref

  7. EXCESS RF POWER REQUIRED FOR RF CONTROL OF THE SPALLATION NEUTRON SOURCE (SNS) LINAC, A PULSED HIGH-INTENSITY SUPERCONDUCTING PROTON ACCELERATOR

    International Nuclear Information System (INIS)

    Lynch, M.; Kwon, S.

    2001-01-01

    A high-intensity proton linac, such as that being planned for the SNS, requires accurate RF control of cavity fields for the entire pulse in order to avoid beam spill. The current design requirement for the SNS is RF field stability within ±0.5% and ±0.5 o [1]. This RF control capability is achieved by the control electronics using the excess RF power to correct disturbances. To minimize the initial capital costs, the RF system is designed with 'just enough' RF power. All the usual disturbances exist, such as beam noise, klystron/HVPS noise, coupler imperfections, transport losses, turn-on and turn-off transients, etc. As a superconducting linac, there are added disturbances of large magnitude, including Lorentz detuning and microphonics. The effects of these disturbances and the power required to correct them are estimated, and the result shows that the highest power systems in the SNS have just enough margin, with little or no excess margin

  8. Neutronic scoping studies for the tokamak experimental power reactor

    International Nuclear Information System (INIS)

    Santoro, R.T.; Bettis, E.S.; McAlees, D.G.; Watts, H.L.; Williams, M.L.

    1976-02-01

    One-dimensional neutron and photon radiation transport methods have been used to investigate candidate blanket configurations and compositions for use in the Tokamak Experimental Power Reactor. Seven blanket designs are compared in terms of energy recovery, radiation attenuation, potential radiation damage, and, where applicable, tritium breeding

  9. Sensitivity Calculation of Vanadium Self-Powered Neutron Detector

    International Nuclear Information System (INIS)

    Cha, Kyoon Ho

    2011-01-01

    Self-powered neutron detector (SPND) is being widely used to monitor the reactor core of the nuclear power plants. The SPND contains a neutron-sensitive metallic emitter surrounded by a ceramic insulator. Currently, the rhodium SPND has been used in many nuclear power plants. The lifetime of rhodium is too short (about 3∼5 years) to operate the nuclear power plant economically. The vanadium (V) SPND is also primarily sensitive to neutrons like rhodium, but is a somewhat slower reaction time as that of a rhodium SPND. The benefit of vanadium over rhodium is its low depletion rate, which is a factor of 7 times less than that of rhodium. For this reason, a vanadium SPND has been being developed to replace the rhodium SPND which is used in OPR1000. Some Monte Carlo simulations were accomplished to calculate the initial sensitivity of vanadium emitter material and alumina (Al 2 O 3 ) insulator with a cylindrical geometry. An MCNP-X code was used to simulate some factors (neutron self shielding factor and electron escape probability from the emitter) necessary to calculate the sensitivity of vanadium detector. The simulation results were compared with some theoretical and experimental values. The method presented here can be used to analyze the optimum design of the vanadium SPND

  10. Neutronics characteristics of space power reactors

    International Nuclear Information System (INIS)

    Little, W.; Barner, J.

    1986-01-01

    The objective of the paper is to describe the neutronic characteristics of a range of possible space reactor designs, and indicate the relative advantages and disadvantages of the various designs. Fuel designs to be considered are cermets (i.e., ceramic particles embedded in a metal matrix) consisting of UO 2 or Nn ceramic particles in matrices of Nb, Mo, Ta, or W. These cermet fuels are compared to a UN pin-type design. UN was selected for the reference fuel material since it has a somewhat higher density than UO 2 (i.e., 14.32 versus 10.96 gm/cc), which allows a lower minimum critical mass for both ceramic and cermet designs

  11. Evaluation of power history during power burst experiments in TRACY by combination of gamma-ray and thermal neutron detectors

    International Nuclear Information System (INIS)

    Yanagisawa, Hiroshi; Ohno, Akio

    2002-01-01

    A combination method using γ-ray and thermal neutron detectors was newly applied to the accurate evaluation of power histories during reactivity-initiated power burst experiments in the Transient Experiment Critical Facility (TRACY). During an initial power burst, the power history was determined using a fast response γ-ray ionization chamber, which was used because of its ability to exactly trace the power history within a short duration of the initial burst. After the initial burst, a micro fission chamber containing highly enriched uranium was used for the determination of the power history because the γ-ray ionization chamber could not be applied due to the contribution of delayed γ-rays from fission products. By the present method, the power histories were evaluated for the experiments in the range of 1.50 to 2.93$ of the reactivity insertion. It was found that the peak power and integrated power as determined by the previous method using only the micro fission chamber were underestimated to be 40% and 30% in maximum, respectively, in comparison with the results from the present evaluation. The numerical simulation performed by using the Monte Carlo method indicated that the underestimation could be comprehended by considering the time delay of thermal neutron detection of the fission chamber, which arose from the flight-time of neutrons from the TRACY core to the fission chamber. (author)

  12. A high-sensitivity neutron counter and waste-drum counting with the high-sensitivity neutron instrument

    International Nuclear Information System (INIS)

    Hankins, D.E.; Thorngate, J.H.

    1993-04-01

    At Lawrence Livermore National Laboratory (LLNL), a highly sensitive neutron counter was developed that can detect and accurately measure the neutrons from small quantities of plutonium or from other low-level neutron sources. This neutron counter was originally designed to survey waste containers leaving the Plutonium Facility. However, it has proven to be useful in other research applications requiring a high-sensitivity neutron instrument

  13. Thermal neutron measurement using the instrumented test bundle and assessment of maximum linear power in HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C. S.; Seo, C. K.; Lee, B. C.; Kim, H. N.; Kang, B. W. [KAERI, Taejon (Korea, Republic of)

    2000-10-01

    The HANARO fuel, U{sub 3}Si-Al, has been developed by AECL and tested in NRU reactor. Due to the lack of the data performed under the high power, the repetitive conduct of the irradiation test was required under the power greater than 108kW/m, which is the estimated maximum linear power in the design stage. Accordingly, the instrumented test bundle with SPND(Self Powered Neutron Detector) was fabricated and its irradiation test was performed in IR2 of HANARO. The measured thermal neutron flux with SPND is compared with calculation results by HANAFMS(HANARO Fuel Management System). The difference in the measured and calculated thermal flux values are below {+-}11% and the accuracy of the linear power predicted by HANAFMS is consequently accompanied. Therefore, it is believed that the maximum linear power above 120kW/m is achieved during the irradiation test of the test bundle.

  14. Conversion of the RB reactor neutrons by highly enriched uranium fuel and lithium deuteride

    International Nuclear Information System (INIS)

    Strugar, P.; Sotic, O.; Ninkovic, M.; Pesic, M.; Altiparmakov, D.

    1981-01-01

    A thermal-to-fast-neutron converter has been constructed at the RB reactor. The material used for the conversion of thermal neutrons is highly enriched uranium fuel of Soviet production applied in Yugoslav heavy water experimental reactors RA and RB. Calculations and preliminary measurements show that the spectrum of converted neutrons only slightly differs from that of fission neutrons. The basic characteristics of converted neutrons can be expressed by the neutron radiation dose of 800 rad (8 Gy) for 1 h of reactor operation at a power level of 1 kW. This dose is approximately 10 times higher than the neutron dose at the same place without converter. At the same time, thermal neutron and gamma radiation doses are negligible. The constructed neutron converter offers wide possibilities for applications in reactor and nuclear physics and similar disciplines, where neutron spectra of high energies are required, as well as in the domain of neutron dosimetry and biological irradiations in homogeneous fields of larger dimensions. The possibility of converting thermal reactor neutrons with energies of about 14 MeV with the aid of lithium deuteride from natural lithium has been considered too. (author)

  15. NICER observations of highly magnetized neutron stars: Initial results

    Science.gov (United States)

    Enoto, Teruaki; Arzoumanian, Zaven; Gendreau, Keith C.; Nynka, Melania; Kaspi, Victoria; Harding, Alice; Guver, Tolga; Lewandowska, Natalia; Majid, Walid; Ho, Wynn C. G.; NICER Team

    2018-01-01

    The Neutron star Interior Composition Explorer (NICER) was launched on June 3, 2017, and attached to the International Space Station. The large effective area of NICER in soft X-rays makes it a powerful tool not only for its primary science objective (diagnostics of the nuclear equation state) but also for studying neutron stars of various classes. As one of the NICER science working groups, the Magnetars and Magnetospheres (M&M) team coordinates monitoring and target of opportunity (ToO) observations of magnetized neutron stars, including magnetars, high-B pulsars, X-ray dim isolated neutron stars, and young rotation-powered pulsars. The M&M working group has performed simultaneous X-ray and radio observations of the Crab and Vela pulsars, ToO observations of the active anomalous X-ray pulsar 4U 0142+61, and a monitoring campaign for the transient magnetar SGR 0501+4516. Here we summarize the current status and initial results of the M&M group.

  16. High pressure neutron powder diffraction at LANSCE

    International Nuclear Information System (INIS)

    Von Dreele, R.B.

    1994-01-01

    By making use of the recently developed ''Paris-Edinburgh'' high pressure cell, the author has successfully performed neutron powder experiments to 10GPa at ambient temperature. Results for the structural compression of the high Tc 1223-Hg superconductor to 9.2 GPa, the compression and possible hydrogen bond formation in brucite, Mg(OD) 2 , to 9.3 GPa, and the molecular reorientation in nitromethane to 5.5 GPa will be presented

  17. Resonant High Power Combiners

    CERN Document Server

    Langlois, Michel; Peillex-Delphe, Guy

    2005-01-01

    Particle accelerators need radio frequency sources. Above 300 MHz, the amplifiers mostly used high power klystrons developed for this sole purpose. As for military equipment, users are drawn to buy "off the shelf" components rather than dedicated devices. IOTs have replaced most klystrons in TV transmitters and find their way in particle accelerators. They are less bulky, easier to replace, more efficient at reduced power. They are also far less powerful. What is the benefit of very compact sources if huge 3 dB couplers are needed to combine the power? To alleviate this drawback, we investigated a resonant combiner, operating in TM010 mode, able to combine 3 to 5 IOTs. Our IOTs being able to deliver 80 kW C.W. apiece, combined power would reach 400 kW minus the minor insertion loss. Values for matching and insertion loss are given. The behavior of the system in case of IOT failure is analyzed.

  18. Neutron activation analysis of high purity substances

    International Nuclear Information System (INIS)

    Gil'bert, Eh.N.

    1987-01-01

    Peculiarities of neutron-activation analysis (NAA) of high purity substances are considered. Simultaneous determination of a wide series of elements, high sensitivity (the lower bound of determined contents 10 -9 -10 -10 %), high selectivity and accuracy (Sr=0.10-0.15, and may be decreased up to 0.001), possibility of analysis of the samples from several micrograms to hundreds of grams, simplicity of calibration may be thought NAA advantages. Questions of accounting of NAA systematic errors associated with the neutron flux screening by the analysed matrix and with production of radionuclides of determined elements from accompanying elements according to concurrent nuclear reactions, as well as accounting of errors due to self-absorption of recorded radiation by compact samples, are considered

  19. High-power klystrons

    Science.gov (United States)

    Siambis, John G.; True, Richard B.; Symons, R. S.

    1994-05-01

    Novel emerging applications in advanced linear collider accelerators, ionospheric and atmospheric sensing and modification and a wide spectrum of industrial processing applications, have resulted in microwave tube requirements that call for further development of high power klystrons in the range from S-band to X-band. In the present paper we review recent progress in high power klystron development and discuss some of the issues and scaling laws for successful design. We also discuss recent progress in electron guns with potential grading electrodes for high voltage with short and long pulse operation via computer simulations obtained from the code DEMEOS, as well as preliminary experimental results. We present designs for high power beam collectors.

  20. Cost optimisation studies of high power accelerators

    Energy Technology Data Exchange (ETDEWEB)

    McAdams, R.; Nightingale, M.P.S.; Godden, D. [AEA Technology, Oxon (United Kingdom)] [and others

    1995-10-01

    Cost optimisation studies are carried out for an accelerator based neutron source consisting of a series of linear accelerators. The characteristics of the lowest cost design for a given beam current and energy machine such as power and length are found to depend on the lifetime envisaged for it. For a fixed neutron yield it is preferable to have a low current, high energy machine. The benefits of superconducting technology are also investigated. A Separated Orbit Cyclotron (SOC) has the potential to reduce capital and operating costs and intial estimates for the transverse and longitudinal current limits of such machines are made.

  1. First PGAA and NAA experimental results from a compact high intensity D-D neutron generator

    International Nuclear Information System (INIS)

    Reijonen, J.; Leung, K.-N.; Firestone, R.B.; English, J.A.; Perry, D.L.; Smith, A.; Gicquel, F.; Sun, M.; Bandong, B.; Garabedian, G.; Revay, Zs.; Szentmiklosi, L.; Molnar, G.

    2003-01-01

    Various types of neutron generator systems have been designed and tested at the Plasma and Ion Source Technology Group at Lawrence Berkeley National Laboratory. These generators are based on a D-D fusion reaction. These high power D-D neutron generators can provide neutron fluxes in excess of the current state of the art D-T neutron generators, without the use of pre-loaded targets or radioactive tritium gas. Safe and reliable long-life operations are the typical features of these D-D generators. All of the neutron generators developed in the Plasma and Ion Source Technology Group are utilizing powerful RF-induction discharge to generate the deuterium plasma. One of the advantages of using the RF-induction discharge is it's ability to generate high fraction of atomic ions from molecular gases, and the ability to generate high plasma densities for high extractable ion current from relatively small discharge volume

  2. High power microwaves

    CERN Document Server

    Benford, James; Schamiloglu, Edl

    2016-01-01

    Following in the footsteps of its popular predecessors, High Power Microwaves, Third Edition continues to provide a wide-angle, integrated view of the field of high power microwaves (HPMs). This third edition includes significant updates in every chapter as well as a new chapter on beamless systems that covers nonlinear transmission lines. Written by an experimentalist, a theorist, and an applied theorist, respectively, the book offers complementary perspectives on different source types. The authors address: * How HPM relates historically and technically to the conventional microwave field * The possible applications for HPM and the key criteria that HPM devices have to meet in order to be applied * How high power sources work, including their performance capabilities and limitations * The broad fundamental issues to be addressed in the future for a wide variety of source types The book is accessible to several audiences. Researchers currently in the field can widen their understanding of HPM. Present or pot...

  3. High-capacity neutron activation analysis facility

    International Nuclear Information System (INIS)

    Hochel, R.C.

    1979-01-01

    A high-capacity neutron activation analysis facility, the Reactor Activation Facility, was designed and built and has been in operation for about a year at one of the Savannah River Plant's production reactors. The facility determines uranium and about 19 other trace elements in hydrogeochemical samples collected in the National Uranium Resource Evaluation program. The facility has a demonstrated average analysis rate of over 10,000 samples per month, and a peak rate of over 16,000 samples per month. Uranium is determined by cyclic activation and delayed neutron counting of the U-235 fission products; other elements are determined from gamma-ray spectra recorded in subsequent irradiation, decay, and counting steps. The method relies on the absolute activation technique and is highly automated for round-the-clock unattended operation

  4. High-capacity neutron activation analysis facility

    International Nuclear Information System (INIS)

    Hochel, R.C.; Bowman, W.W.; Zeh, C.W.

    1980-01-01

    A high-capacity neutron activation analysis facility, the Reactor Activation Facility, was designed and built and has been in operation for about a year at one of the Savannah River Plant's production reactors. The facility determines uranium and about 19 other elements in hydrogeochemical samples collected in the National Uranium Resource Evaluation program, which is sponsored and funded by the United States Department of Energy, Grand Junction Office. The facility has a demonstrated average analysis rate of over 10,000 samples per month, and a peak rate of over 16,000 samples per month. Uranium is determined by cyclic activation and delayed neutron counting of the U-235 fission products; other elements are determined from gamma-ray spectra recorded in subsequent irradiation, decay, and counting steps. The method relies on the absolute activation technique and is highly automated for round-the-clock unattended operation

  5. Development of self-powered neutron detectors for neutron flux monitoring in HCLL and HCPB ITER-TBM

    International Nuclear Information System (INIS)

    Angelone, M.; Klix, A.; Pillon, M.; Batistoni, P.; Fischer, U.; Santagata, A.

    2014-01-01

    Highlights: •Self powered neutron detector (SPND) is attractive neutron monitor for TBM in ITER. •In hard neutron spectra (e.g. TBM) there is the need to optimize their response. •Three state-of-the-art SPNDs were tested using fast and 14 MeV neutrons. •The response of SPNDs is much lower than in thermal neutron flux. •FISPACT calculations performed to find out candidate materials in hard spectra. -- Abstract: Self powered neutron detectors (SPND) have a number of interesting properties (e.g. small dimensions, capability to operate in harsh environments, absence of external bias), so they are attractive neutron monitors for TBM in ITER. However, commercially available SPNDs are optimized for operation in a thermal nuclear reactor where the neutron spectrum is much softer than that expected in a TBM. This fact can limit the use of SPND in a TBM since the effective cross sections for the production of beta emitters are much lower in a fast neutron spectrum. This work represents the first attempt to study SPNDs as neutron flux monitors for TBM. Three state-of-the-art SPND available on the market were bought and tested using fast neutrons at TAPIRO fast neutron source of ENEA Casaccia and with 14 MeV neutrons at the Frascati neutron generator (FNG). The results clearly indicate that in fast neutron spectra, the response of SPNDs is much lower than in thermal neutron flux. Activation calculations were performed using the FISPACT code to find out possible material candidates for SPND suitable for operation in TBM neutron spectra

  6. Development of self-powered neutron detectors for neutron flux monitoring in HCLL and HCPB ITER-TBM

    Energy Technology Data Exchange (ETDEWEB)

    Angelone, M., E-mail: maurizio.angelone@enea.it [Associazione ENEA-EURATOM sulla FusioneENEA C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Klix, A. [Association KIT-EURATOM, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Pillon, M.; Batistoni, P. [Associazione ENEA-EURATOM sulla FusioneENEA C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Fischer, U. [Association KIT-EURATOM, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Santagata, A. [ENEA C.R. Casaccia, via Anguillarese Km. 1,300, 00100 Roma (Italy)

    2014-10-15

    Highlights: •Self powered neutron detector (SPND) is attractive neutron monitor for TBM in ITER. •In hard neutron spectra (e.g. TBM) there is the need to optimize their response. •Three state-of-the-art SPNDs were tested using fast and 14 MeV neutrons. •The response of SPNDs is much lower than in thermal neutron flux. •FISPACT calculations performed to find out candidate materials in hard spectra. -- Abstract: Self powered neutron detectors (SPND) have a number of interesting properties (e.g. small dimensions, capability to operate in harsh environments, absence of external bias), so they are attractive neutron monitors for TBM in ITER. However, commercially available SPNDs are optimized for operation in a thermal nuclear reactor where the neutron spectrum is much softer than that expected in a TBM. This fact can limit the use of SPND in a TBM since the effective cross sections for the production of beta emitters are much lower in a fast neutron spectrum. This work represents the first attempt to study SPNDs as neutron flux monitors for TBM. Three state-of-the-art SPND available on the market were bought and tested using fast neutrons at TAPIRO fast neutron source of ENEA Casaccia and with 14 MeV neutrons at the Frascati neutron generator (FNG). The results clearly indicate that in fast neutron spectra, the response of SPNDs is much lower than in thermal neutron flux. Activation calculations were performed using the FISPACT code to find out possible material candidates for SPND suitable for operation in TBM neutron spectra.

  7. Neutron sensitivity of prompt-response self-powered neutron detectors and the interval rule

    International Nuclear Information System (INIS)

    Molina Avila, J.; Carmolopes, M.

    1989-01-01

    This paper is devoted to the calculation of thermal s th and epithermal s epi sensitivities of cobalt prompt-response Self-Powered Neutron Detectors (SPNDs). The thermal sensitivity was obtained for a Maxwellian neutron field, and the effect of scattering on the self-shielding correction was taken into consideration in the second-collision approximation. The dependence of s th on the emitter radius R was studied in a wide region of R (0.025 to 0.2 cm). The differential and global epithermal sensitivities were calculated using a simple expression for the first-collision neutron absorption probability. Finally, a criterion to evaluate the accuracy of the parameters of the model was established in the form of some Interval Rule which is very sensitive to the radial dependence of the flux perturbation correction and other parameters of the model in both the thermal and epithermal regions

  8. A Novel Detector for High Neutron Flux Measurements

    International Nuclear Information System (INIS)

    Singo, T. D.; Wyngaardt, S. M.; Papka, P.; Dobson, R. T.

    2010-01-01

    Measuring alpha particles from a neutron induced break-up reaction with a mass spectrometer can be an excellent tool for detecting neutrons in a high neutron flux environment. Break-up reactions of 6 Li and 12 C can be used in the detection of slow and fast neutrons, respectively. A high neutron flux detection system that integrates the neutron energy sensitive material and helium mass spectrometer has been developed. The description of the detector configuration is given and it is soon to be tested at iThemba LABS, South Africa.

  9. Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux

    Science.gov (United States)

    Bowman, Charles D.

    1992-01-01

    Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

  10. Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux

    Science.gov (United States)

    Bowman, C.D.

    1992-11-03

    Apparatus for nuclear transmutation and power production using an intense accelerator-generated thermal neutron flux. High thermal neutron fluxes generated from the action of a high power proton accelerator on a spallation target allows the efficient burn-up of higher actinide nuclear waste by a two-step process. Additionally, rapid burn-up of fission product waste for nuclides having small thermal neutron cross sections, and the practicality of small material inventories while achieving significant throughput derive from employment of such high fluxes. Several nuclear technology problems are addressed including 1. nuclear energy production without a waste stream requiring storage on a geological timescale, 2. the burn-up of defense and commercial nuclear waste, and 3. the production of defense nuclear material. The apparatus includes an accelerator, a target for neutron production surrounded by a blanket region for transmutation, a turbine for electric power production, and a chemical processing facility. In all applications, the accelerator power may be generated internally from fission and the waste produced thereby is transmuted internally so that waste management might not be required beyond the human lifespan.

  11. A high gain energy amplifier operated with fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Rubbia, C. [CERN, Geneva (Switzerland)

    1995-10-01

    The basic concept and the main practical considerations of an Energy Amplifier (EA) have been exhaustively described elsewhere. Here the concept of the EA is further explored and additional schemes are described which offer a higher gain, a larger maximum power density and an extended burn-up. All these benefits stem from the use of fast neutrons, instead of thermal or epithermal ones, which was the case in the original study. The higher gain is due both to a more efficient high energy target configuration and to a larger, practical value of the multiplication factor. The higher power density results from the higher permissible neutron flux, which in turn is related to the reduced rate of {sup 233}Pa neutron captures (which, as is well known, suppress the formation of the fissile {sup 233}U fuel) and the much smaller k variations after switch-off due to {sup 233}Pa decays for a given burn-up rate. Finally a longer integrated burn-up is made possible by reduced capture rate by fission fragments of fast neutrons. In practice a 20 MW proton beam (20 mA @ 1 GeV) accelerated by a cyclotron will suffice to operate a compact EA at the level of {approx} 1 GW{sub e}. The integrated fuel burn-up can be extended in excess of 100 GW d/ton, limited by the mechanical survival of the fuel elements. Radio-Toxicity accumulated at the end of the cycle is found to be largely inferior to the one of an ordinary Reactor for the same energy produced. Schemes are proposed which make a {open_quotes}melt-down{close_quotes} virtually impossible. The conversion ratio, namely the rate of production of {sup 233}U relative to consumption is generally larger than unity, which permits production of fuel for other uses. Alternatively the neutron excess can be used to transform unwanted {open_quotes}ashes{close_quotes} into more acceptable elements.

  12. Neutron activation analysis of high purity tellurium

    International Nuclear Information System (INIS)

    Gil'bert, Eh.N.; Verevkin, G.V.; Obrazovskij, E.G.; Shatskaya, S.S.

    1980-01-01

    A scheme of neutron activation analysis of high purity tellurium is developed. Weighed amount of Te (0.5 g) is irradiated for 20-40 hr in the flux of 2x10 13 neutron/(cm 2 xs). After decomposition of the sample impurities of gold and palladium are determined by the extraction with organic sulphides. Tellurium separation from the remaining impurities is carried out by the extraction with monothiobenzoic acid from weakly acidic HCl solutions in the presence of iodide-ions, suppressing silver extraction. Remaining impurity elements in the refined product are determined γ-spectrometrically. The method allows to determine 34 impurities with determination limits 10 -6 -10 -11 g

  13. MCNP and visualization of neutron flux and power distributions

    International Nuclear Information System (INIS)

    Snoj, L.; Lengar, I.; Zerovnik, G.; Ravnik, M.

    2009-01-01

    The visualization of neutron flux and power distributions in two nuclear reactors (TRIG A type research reactor and typical PWR) and one thermonuclear reactor (tokamak type) are treated in the paper. The distributions are calculated with MCNP computer code and presented using Amira and Voxler software. The results in the form of figures are presented in the paper together with comments qualitatively explaining the figures. The remembrance of most of the people is better, if they visualize a process. Therefore a representation of the reactor and neutron transport parameters is a convenient modern educational tool for (nuclear power plant) operators, nuclear engineers, students and specialists involved in reactor operation and design. Visualization is applicable not only in education and training, but also as a tool for core and irradiation planning. (authors)

  14. High Intensity, Pulsed, D-D Neutron Generator

    International Nuclear Information System (INIS)

    Williams, D.L.; Vainionpaa, J.H.; Jones, G.; Piestrup, M.A.; Gary, C.K.; Harris, J.L.; Fuller, M.J.; Cremer, J.T.; Ludewigt, Bernhard A.; Kwan, J.W.; Reijonen, J.; Leung, K.-N.; Gough, R.A.

    2008-01-01

    Single ion-beam RF-plasma neutron generators are presented as a laboratory source of intense neutrons. The continuous and pulsed operations of such a neutron generator using the deuterium-deuterium fusion reaction are reported. The neutron beam can be pulsed by switching the RF plasma and/or a gate electrode. These generators are actively vacuum pumped so that a continuous supply of deuterium gas is present for the production of ions and neutrons. This contributes to the generator's long life. These single-beam generators are capable of producing up to 1E10 n/s. Previously, Adelphi and LBNL have demonstrated these generators applications in fast neutron radiography, Prompt Gamma Neutron Activation Analysis (PGNAA) and Neutron Activation Analysis (NAA). Together with an inexpensive compact moderator, these high-output neutron generators extend useful applications to home laboratory operations.

  15. Switching power converters medium and high power

    CERN Document Server

    Neacsu, Dorin O

    2013-01-01

    An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

  16. Los Alamos high-power proton linac designs

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, G.P. [Los Alamos National Laboratory, NM (United States)

    1995-10-01

    Medium-energy high-power proton linear accelerators have been studied at Los Alamos as drivers for spallation neutron applications requiring large amounts of beam power. Reference designs for such accelerators are discussed, important design factors are reviewed, and issues and concern specific to this unprecedented power regime are discussed.

  17. Science opportunities at high power accelerators like APT

    International Nuclear Information System (INIS)

    Browne, J.C.

    1996-01-01

    This paper presents applications of high power RF proton linear accelerators to several fields. Radioisotope production is an area in which linacs have already provided new isotopes for use in medical and industrial applications. A new type of spallation neutron source, called a long-pulse spallation source (LPSS), is discussed for application to neutron scattering and to the production and use of ultra-cold neutrons (UCN). The concept of an accelerator-driven, transmutation of nuclear waste system, based on high power RF linac technology, is presented along with its impact on spent nuclear fuels

  18. Numerical and experimental investigations to describe the mode of operation and effectivity of large surface high sensitive SPNDs (Self-Powered-Neutron-Detectors)

    International Nuclear Information System (INIS)

    Al-Dabagh, D.

    1981-08-01

    First a computer model for the parametric calculation of the (n,γ)-reaction rates in the emitter of the SPND was developed under use of the Monte-Carlo Program KENO II. To determine the escape-probability of the electrons produced via Compton- or photoelectric effect by the emitter as well as from the surrounding isolator, a new Monte-Carlo-Program was implemented under consideration of the Klein-Nishina-formula and the energy-range relationships for electrons. The approximate calculations performed for the electrons produced in the isolator show that the 'isolator flux' can give an important contribution to the total signal of the SPND. Subsequently with this program system an optimization of the neutron sensitivity was performed by a suitable choice of geometry (emitter thickness, isolator thickness). For a specially built large surface SPND with Gadolinium-emitter the neutron sensitivity was calculated. These results were checked by an In-Pile-Experiment in the FRJ-1 reactor. Very good agreement was found. The detector was also shown to exhibit excellent linearity and showed also the expected enhanced sensitivity. (orig./HP) [de

  19. Spectral correction factors for conventional neutron dosemeters used in high-energy neutron environments

    International Nuclear Information System (INIS)

    Lee, K.W.; Sheu, R.J.

    2015-01-01

    High-energy neutrons (>10 MeV) contribute substantially to the dose fraction but result in only a small or negligible response in most conventional moderated-type neutron detectors. Neutron dosemeters used for radiation protection purpose are commonly calibrated with 252 Cf neutron sources and are used in various workplace. A workplace-specific correction factor is suggested. In this study, the effect of the neutron spectrum on the accuracy of dose measurements was investigated. A set of neutron spectra representing various neutron environments was selected to study the dose responses of a series of Bonner spheres, including standard and extended-range spheres. By comparing 252 Cf-calibrated dose responses with reference values based on fluence-to-dose conversion coefficients, this paper presents recommendations for neutron field characterisation and appropriate correction factors for responses of conventional neutron dosemeters used in environments with high-energy neutrons. The correction depends on the estimated percentage of high-energy neutrons in the spectrum or the ratio between the measured responses of two Bonner spheres (the 4P6-8 extended-range sphere versus the 6'' standard sphere). (authors)

  20. Neutron scattering on liquid He4 at high momentum transfers

    International Nuclear Information System (INIS)

    Parlinski, K.

    1975-01-01

    Using the Sears method of expansion of the dynamic structure factor into a series over the inverse powers of the wave vector and five moments of the velocity correlation function, the distribution of neutrons scattered on liquid helium at T=0 K and at the momentum transfer k=14.33 A -1 is calculated. The calculated distribution takes into account the interaction among helium atoms. The distributions are compared with the experimental data. The results show that proper information of the occupation fraction of the zero-momentum state - the condensate - can be obtained by the neutron scatterng method at high-momentum transfers only when the interaction among helium atoms is taken into account. (author)

  1. Orion, a high efficiency 4π neutron detector

    International Nuclear Information System (INIS)

    Crema, E.; Piasecki, E.; Wang, X.M.; Doubre, H.; Galin, J.; Guerreau, D.; Pouthas, J.; Saint-Laurent, F.

    1990-01-01

    In intermediate energy heavy ion collisions the multiplicity of emitted neutrons is strongly connected to energy dissipation and to impact parameter. We present the 4π detector ORION, a high efficiency liquid scintillator detector which permits to get information on the multiplicity of neutrons measured event-wise and on the spatial distribution of these neutrons [fr

  2. High resolution Neutron and Synchrotron Powder Diffraction

    International Nuclear Information System (INIS)

    Hewat, A.W.

    1986-01-01

    The use of high-resolution powder diffraction has grown rapidly in the past years, with the development of Rietveld (1967) methods of data analysis and new high-resolution diffractometers and multidetectors. The number of publications in this area has increased from a handful per year until 1973 to 150 per year in 1984, with a ten-year total of over 1000. These papers cover a wide area of solid state-chemistry, physics and materials science, and have been grouped under 20 subject headings, ranging from catalysts to zeolites, and from battery electrode materials to pre-stressed superconducting wires. In 1985 two new high-resolution diffractometers are being commissioned, one at the SNS laboratory near Oxford, and one at the ILL in Grenoble. In different ways these machines represent perhaps the ultimate that can be achieved with neutrons and will permit refinement of complex structures with about 250 parameters and unit cell volumes of about 2500 Angstrom/sp3/. The new European Synchotron Facility will complement the Grenoble neutron diffractometers, and extend the role of high-resolution powder diffraction to the direct solution of crystal structures, pioneered in Sweden

  3. Staged Z-pinch Experiments at the 1MA Zebra pulsed-power generator: Neutron measurements

    Science.gov (United States)

    Ruskov, Emil; Darling, T.; Glebov, V.; Wessel, F. J.; Anderson, A.; Beg, F.; Conti, F.; Covington, A.; Dutra, E.; Narkis, J.; Rahman, H.; Ross, M.; Valenzuela, J.

    2017-10-01

    We report on neutron measurements from the latest Staged Z-pinch experiments at the 1MA Zebra pulsed-power generator. In these experiments a hollow shell of argon or krypton gas liner, injected between the 1 cm anode-cathode gap, compresses a deuterium plasma target of varying density. Axial magnetic field Bz neutron Time of Flight (nTOF) detectors are augmented with a large area ( 1400 cm2) liquid scintillator detector to which fast gatedPhotek photomultipliers are attached. Sample data from these neutron diagnostics systems is presented. Consistently high neutron yields YDD >109 are measured, with highest yield of 2.6 ×109 . A pair of horizontally and vertically placed plastic scintillator nTOFs suggest isotropic i.e. thermonuclear origin of the neutrons produced. nTOF data from the liquid scintillator detector was cross-calibrated with the silver activation detector, and can be used for accurate calculation of the neutron yield. Funded by the Advanced Research Projects Agency - Energy, under Grant Number DE-AR0000569.

  4. Neutron streaming evaluation for the DREAM fusion power reactor

    International Nuclear Information System (INIS)

    Seki, Yasushi; Nishio, Satoshi; Ueda, Shuzo; Kurihara, Ryoichi

    2000-01-01

    Aiming at high degree of safety and benign environmental effect, we have proposed a tokamak fusion reactor concept called DREAM, which stands for DRastically EAsy Maintenance Reactor. The blanket structure of the reactor is made from very low activation SiC/SiC composites and cooled by non-reactive helium gas. High net thermal efficiency of about 50% is realized by 900 C helium gas and high plant availability is possible with simple maintenance scheme. In the DREAM Reactor, neutron streaming is a big problem because cooling pipes with diameter larger than 80 cm are used for blanket heat removal. Neutron streaming through the cooling pipes could cause hot spots in the superconducting magnets adjacent to the cooling pipes to shorten the magnet lifetime or increase cryogenic cooling requirement. Neutron streaming could also activate components such as gas turbine further away from the fusion plasma. The effect of neutron streaming through the helium cooling pipes was evaluated for the two types of cooling pipe extraction scheme. The result of a preliminary calculation indicates the gas turbine activation prohibits personnel access in the case of inboard pipe extraction while with additional shielding measures, limited contact maintenance is possible in the case of outboard extraction. (author)

  5. Construction of a self-powered neutron detector prototype

    International Nuclear Information System (INIS)

    Pombo, J.B.S.M.; Correa, R.F.

    1986-01-01

    Description and testing of a self-powered neutron detector and related current measurement electronics, in construction at Centro de Desenvolviemnto da Tecnologia Nuclear (CDTN), are presented. The cylindrical detector has a 9-wires cobalt emitter, Inconel 600 tubing collector and sinterized alumina electrical insulation. The bifilar signal cable is plugged to the detector through a SHV connector. Preliminary testing has giving information about dielectrical properties of the set and impurities of the materials (by means of activation analysis). The main tests, done in a 100 KW Triga Reactor, allowed the verification of the detector response to the neutron flux, the stability and reproducibility of this response, and also the evaluation of sensitivity to gamma radiation. The detector performance is considered good. (Author) [pt

  6. Kalman filtering of self-powered neutron detectors

    International Nuclear Information System (INIS)

    Kantrowitz, M.L.

    1992-01-01

    Pressurized water reactors employ a wide variety of in-core detectors to determine the neutronic behavior within the core. Among the detectors used are rhodium and vanadium self-powered detectors (SPDs), which are very accurate, but respond slowly to changes in neutron flux. This paper describes a new dynamic compensation algorithm, based on Kalman filtering, which converts delayed-responding rhodium and vanadium SPDs into prompt-responding detectors by reconstructing the dynamic flux signal sensed by the detectors from the prompt and delayed components. This conversion offers the possibility of utilizing current fixed in-core detector systems based on these delayed-responding detectors for core control and/or core protection functions without the need for fixed in-core detectors which are prompt-responding. As a result, the capabilities of current fixed in-core detector systems could be expanded significantly without a major hardware investment

  7. Kalman filtering for rhodium self-powered neutron detectors

    International Nuclear Information System (INIS)

    Kantrowitz, M.L.

    1988-01-01

    Rhodium self-powered neutron detectors are utilized in many pressurized water reactors to determine the neutronic behavior within the core. In order to compensate for the inherent time delay associated with the response of these detectors, a dynamic compensation algorithm is currently used in Combustion Engineering plants to reconstruct the dynamic flux signal which is being sensed by the rhodium detectors. This paper describes a new dynamic compensation algorithm, based on Kalman filtering, which improves on the noise gain and response time characteristics of the algorithm currently used, and offers the possibility of utilizing the proven rhodium detector based fixed in-core detector system as an integral part of advanced core control and/or protection systems

  8. High Power Density Motors

    Science.gov (United States)

    Kascak, Daniel J.

    2004-01-01

    With the growing concerns of global warming, the need for pollution-free vehicles is ever increasing. Pollution-free flight is one of NASA's goals for the 21" Century. , One method of approaching that goal is hydrogen-fueled aircraft that use fuel cells or turbo- generators to develop electric power that can drive electric motors that turn the aircraft's propulsive fans or propellers. Hydrogen fuel would likely be carried as a liquid, stored in tanks at its boiling point of 20.5 K (-422.5 F). Conventional electric motors, however, are far too heavy (for a given horsepower) to use on aircraft. Fortunately the liquid hydrogen fuel can provide essentially free refrigeration that can be used to cool the windings of motors before the hydrogen is used for fuel. Either High Temperature Superconductors (HTS) or high purity metals such as copper or aluminum may be used in the motor windings. Superconductors have essentially zero electrical resistance to steady current. The electrical resistance of high purity aluminum or copper near liquid hydrogen temperature can be l/lOO* or less of the room temperature resistance. These conductors could provide higher motor efficiency than normal room-temperature motors achieve. But much more importantly, these conductors can carry ten to a hundred times more current than copper conductors do in normal motors operating at room temperature. This is a consequence of the low electrical resistance and of good heat transfer coefficients in boiling LH2. Thus the conductors can produce higher magnetic field strengths and consequently higher motor torque and power. Designs, analysis and actual cryogenic motor tests show that such cryogenic motors could produce three or more times as much power per unit weight as turbine engines can, whereas conventional motors produce only 1/5 as much power per weight as turbine engines. This summer work has been done with Litz wire to maximize the current density. The current is limited by the amount of heat it

  9. High-power electronics

    CERN Document Server

    Kapitsa, Petr Leonidovich

    1966-01-01

    High-Power Electronics, Volume 2 presents the electronic processes in devices of the magnetron type and electromagnetic oscillations in different systems. This book explores the problems of electronic energetics.Organized into 11 chapters, this volume begins with an overview of the motion of electrons in a flat model of the magnetron, taking into account the in-phase wave and the reverse wave. This text then examines the processes of transmission of electromagnetic waves of various polarization and the wave reflection from grids made of periodically distributed infinite metal conductors. Other

  10. High Power Vanadate lasers

    CSIR Research Space (South Africa)

    Strauss

    2006-07-01

    Full Text Available stream_source_info Strauss1_2006.pdf.txt stream_content_type text/plain stream_size 3151 Content-Encoding UTF-8 stream_name Strauss1_2006.pdf.txt Content-Type text/plain; charset=UTF-8 Laser Research Institute... University of Stellenbosch www.laser-research.co.za High Power Vanadate lasers H.J.Strauss, Dr. C. Bollig, R.C. Botha, Prof. H.M. von Bergmann, Dr. J.P. Burger Aims 1) To develop new techniques to mount laser crystals, 2) compare the lasing properties...

  11. High sensitivity MOSFET-based neutron dosimetry

    International Nuclear Information System (INIS)

    Fragopoulou, M.; Konstantakos, V.; Zamani, M.; Siskos, S.; Laopoulos, T.; Sarrabayrouse, G.

    2010-01-01

    A new dosemeter based on a metal-oxide-semiconductor field effect transistor sensitive to both neutrons and gamma radiation was manufactured at LAAS-CNRS Laboratory, Toulouse, France. In order to be used for neutron dosimetry, a thin film of lithium fluoride was deposited on the surface of the gate of the device. The characteristics of the dosemeter, such as the dependence of its response to neutron dose and dose rate, were investigated. The studied dosemeter was very sensitive to gamma rays compared to other dosemeters proposed in the literature. Its response in thermal neutrons was found to be much higher than in fast neutrons and gamma rays.

  12. Testing Procedures and Results of the Prototype Fundamental Power Coupler for the Spallation Neutron Source

    International Nuclear Information System (INIS)

    M. Stirbet; I.E. Campisi; E.F. Daly; G.K. Davis; M. Drury; P. Kneisel; G. Myneni; T. Powers; W.J. Schneider; K.M. Wilson; Y. Kang; K.A. Cummings; T. Hardek

    2001-01-01

    High-power RF testing with peak power in excess of 500 kW has been performed on prototype Fundamental Power Couplers (FPC) for the Spallation Neutron Source superconducting (SNS) cavities. The testing followed the development of procedures for cleaning, assembling and preparing the FPC for installation in the test stand. The qualification of the couplers has occurred for the time being only in a limited set of conditions (travelling wave, 20 pps) as the available RF system and control instrumentation are under improvement

  13. Polarized neutron reflectometry in high magnetic fields

    International Nuclear Information System (INIS)

    Fritzsche, H.

    2005-01-01

    A simple method is described to maintain the polarization of a neutron beam on its way through the large magnetic stray fields produced by a vertical field of a cryomagnet with a split-coil geometry. The two key issues are the proper shielding of the neutron spin flippers and an additional radial field component in order to guide the neutron spin through the region of the null point (i.e., point of reversal for the vertical field component). Calculations of the neutron's spin rotation as well as polarized neutron reflectometry experiments on an ErFe 2 /DyFe 2 multilayer show the perfect performance of the used setup. The recently commissioned cryomagnet M5 with a maximum vertical field of up to 7.2 T in asymmetric mode for polarized neutrons and 9 T in symmetric mode for unpolarized neutrons was used on the C5 spectrometer in reflectometry mode, at the NRU reactor in Chalk River, Canada

  14. High-lying neutron hole strengths observed in pick-up reactions

    International Nuclear Information System (INIS)

    Gales, S.

    1980-01-01

    Neutron-hole states in orbits well below the Fermi surface have been observed in a number of medium-heavy nuclei from A=90 to 209 using one nucleon pick-up reactions. The excitation energies, angular distributions of such broad and enhanced structures will be discussed. The fragmentation of the neutron-hole strengths as well as the spreading of such simple mode of excitations into more complex states are compared to recent calculations within the quasiparticle-phonon or the single particle-vibration coupling nuclear models. We report on recent measurements of J for inner-hole states in 89 Zr and 115 Sn 119 Sn using the analyzing power of the (p,d) and (d,t) reactions. Large enhancement of cross-sections are observed at high excitation energy in the study of the (p,t) reactions on Zr, Cd, Sn, Te and Sm isotopes. The systematic features of such high-lying excitation are related to the ones observed in one neutron pick-up experiments. The origin of such concentration of two neutron-hole strengths in Cd and Sn isotopes will be discussed. Preliminary results obtained in the study of the (α, 6 He) reaction at 218 MeV incident energy on 90 Zr, 118 Sn and 208 Pb targets are presented and compared to the (p,t) results. Finally the properties of hole-analog states populated in neutron pick-up reactions (from 90 Zr to 208 Pb) will be presented

  15. Neutronics requirements for a DEMO fusion power plant

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, U., E-mail: ulrich.fischer@kit.edu [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Bachmann, C. [EUROfusion Consortium , Boltzmannstraße 2, 85748 Garching (Germany); Palermo, I. [Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid (Spain); Pereslavtsev, P. [Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany); Villari, R. [ENEA UT-FUS C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy)

    2015-10-15

    Highlights: • Discussion and specification of neutronic requirements for a DEMO power plant. • TBR uncertainties are reviewed/discussed and design margins are elaborated. • Limits are given for radiation loads to super-conducting magnets and steel structural components. • Available DEMO results are compared to recommended limits and TBR design target. - Abstract: This paper addresses the neutronic requirements a DEMO fusion power plant needs to fulfil for a reliable and safe operation. The major requirement is to ensure Tritium self-sufficiency taking into account the various uncertainties and plant-internal losses that occur during DEMO operation. A further major requirement is to ensure sufficient protection of the superconducting magnets against the radiation penetrating in-vessel components and vessel. Reliable criteria for the radiation loads need to be defined and verified to ensure the reliable operation of the magnets over the lifetime of DEMO. Other issues include radiation induced effects on structural materials such as the accumulated displacement damage, the generation of gases such as helium which may deteriorate the material performance. The paper discusses these issues and their impact on design options for DEMO taking into account results obtained in the frame of European Power Plant Physics and Technology (PPPT) 2013 programme activities with DEMO models employing the helium cooled pebble bed (HCPB), the helium cooled lithium lead (HCLL), and the water-cooled (WCLL) blanket concepts.

  16. High power coaxial ubitron

    Science.gov (United States)

    Balkcum, Adam J.

    In the ubitron, also known as the free electron laser, high power coherent radiation is generated from the interaction of an undulating electron beam with an electromagnetic signal and a static periodic magnetic wiggler field. These devices have experimentally produced high power spanning the microwave to x-ray regimes. Potential applications range from microwave radar to the study of solid state material properties. In this dissertation, the efficient production of high power microwaves (HPM) is investigated for a ubitron employing a coaxial circuit and wiggler. Designs for the particular applications of an advanced high gradient linear accelerator driver and a directed energy source are presented. The coaxial ubitron is inherently suited for the production of HPM. It utilizes an annular electron beam to drive the low loss, RF breakdown resistant TE01 mode of a large coaxial circuit. The device's large cross-sectional area greatly reduces RF wall heat loading and the current density loading at the cathode required to produce the moderate energy (500 keV) but high current (1-10 kA) annular electron beam. Focusing and wiggling of the beam is achieved using coaxial annular periodic permanent magnet (PPM) stacks without a solenoidal guide magnetic field. This wiggler configuration is compact, efficient and can propagate the multi-kiloampere electron beams required for many HPM applications. The coaxial PPM ubitron in a traveling wave amplifier, cavity oscillator and klystron configuration is investigated using linear theory and simulation codes. A condition for the dc electron beam stability in the coaxial wiggler is derived and verified using the 2-1/2 dimensional particle-in-cell code, MAGIC. New linear theories for the cavity start-oscillation current and gain in a klystron are derived. A self-consistent nonlinear theory for the ubitron-TWT and a new nonlinear theory for the ubitron oscillator are presented. These form the basis for simulation codes which, along

  17. Solar powered irrigation management using neutron scattering technique

    International Nuclear Information System (INIS)

    Hegazi, A.M.A

    2010-01-01

    designed (metal frame, detecting sensors and DC motor with gear-box) and used for this purpose. 28% more power output was gained.3.Matching system components with DC motor obtained from local markets to meet PV generator performance. Performance curves of both PV generator and DC motor was plotted.4.Setting up a pumping system matches the PV output, pump efficiency was calculated (30%) at 1100 rpm.5.Hourly pump discharge and reference evapotranspiration (ET o ) were estimated using 10 years meteorological data averages (Meteo-Norm Software), years (1995-2005). Analysis showed that the strongest correlation was between the solar radiation and ET o , while solar radiation with other parameters affecting ET o such as temperature, RH% were not that strong. Correlations between both hourly solar radiation and air temperature were positive and highly significant. Calculations were made to determine area to be cultivated using the pumping system under study, to meet ET o . Results ranged from more than 4 feddan at winter time to 2.3 feddan in summer season. 6. Determination of actual evapotranspiration (ET o ) using neutron moisture meter for the evaluation of estimated (ET o ). Actual evapotranspiration (ET a ) values were calculated within the wet area around emitter (location of plant) in five sites (S1, S2, S3, S4 and S5). Average ET a values for three replicates for the five sites in developing stage of squash plant were calculated.

  18. Neutronic design studies for an unattended, low power reactor

    International Nuclear Information System (INIS)

    Palmer, R.G.; Durkee, J.W. Jr.

    1986-01-01

    The Los Alamos National Laboratory is involved in the design and demonstrations of a small, long-lived nuclear heat and electric power source for potential applications at remote sites where alternate fossil energy systems would not be cost effective. This paper describes the neutronic design analysis that was performed to arrive at two conceptual designs, one using thermoelectric conversion, the other using an organic Rankine cycle. To meet the design objectives and constraints a number of scoping and optimization studies were carried out. The results of calculations of control worths, temperature coefficients of reactivity and fuel depletion effects are reported

  19. Design and fabrication of a self-powered neutron detector

    International Nuclear Information System (INIS)

    Garcia Garcia, Florencio.

    1979-01-01

    Self powered neutron detectors are becoming more and more popular in reactor instrumentation. A fast response detector of this type was made at the Reactor Division, La Reina Nuclear Center in Santiago. Cobalt wire was the emitter, teflon the insulator and a stainless steel tubing was the collector. The overall dimensions of the detector are 6 mms diameter and 700 mms length. The irradiation tests, carried out at the Center's 5 Mw research reactor showed a very reasonably linear relation between current supplied by the detector and thermal neutron flux, over a range extending from 10 10 to 10 13 n/cm 2 x seg. These tests also showed a good agreement between calculated and measured current. The models used for the calculation of current are fully explained and they include some improvements over those that have been published recently. An important conclusion for the case of the cobalt detectors is that the wire's diameter must be at least 1 mm. in order to have a neutron induced current bigger than the parasitic components generated by indirect processes. Calculations for other emitters such as vanadium, silver and rhodum are also included. (EC)

  20. Report on high energy neutron dosimetry workshop

    International Nuclear Information System (INIS)

    Alvar, K.R.; Gavron, A.

    1993-01-01

    The workshop was called to assess the performance of neutron dosimetry per the responses from ten DOE accelerator facilities to an Office of Energy Research questionnaire regarding implementation of a personnel dosimetry requirement in DRAFT DOE 5480.ACC, ''Safety of Accelerator Facilities''. The goals of the workshop were to assess the state of dosimetry at high energy accelerators and if such dosimetry requires improvement, to reach consensus on how to proceed with such improvements. There were 22 attendees, from DOE Programs and contract facilities, DOE, Office of Energy Research (ER), Office of Environmental Safety and Health (EH), Office of Fusion Energy, and the DOE high energy accelerator facilities. A list of attendees and the meeting agenda are attached. Copies of the presentations are also attached

  1. Thermofluid-neutronic stability of the rotating, fluidized bed, space-power reactor

    International Nuclear Information System (INIS)

    Lee, C.C.; Jones, O.C.; Becker, M.

    1993-01-01

    A rotating fluidized bed nuclear reactor has the potential of being a vary attractive option for ultra-high power space systems, especially for propulsion. Research has already examined fuel bed expansion due to variations in state variables, propellant flow rate, and rotational speed, and has also considered problems related to thermal stress. This paper describes the results of a coupled thermofluid-neutronic analysis where perturbations in fuel bed height caused by maneuvering changes in operating conditions alter power levels due to varying absorption of neutrons which would otherwise leak from the system, mainly through the nozzle. This first analysis was not a detailed stability analysis. Rather, it utilized simplified neutronic methods, and was intended to provide an order-of-magnitude assessment of the stability of the reactor with the intention to determine whether or not stability might be a 'concept killer'. Stability was compared with a fixed-fuel-bed reactor of identical geometry for three different cases comprising a set of small, medium and large sizes/powers from 250 MW to 5 GW. It was found that power fluctuations in the fluidized bed reactor were larger by 100 db or more than expected in a packed bed reactor of the same geometry, but never resulted in power excursions. Margins to unit gain in some cases, however, were sufficiently small that the approximations in this quasi-2-dimensional model may not be sufficiently accurate to preclude significant excursions. (orig.)

  2. Neutron-deuteron analyzing power data at En=22.5 MeV

    Science.gov (United States)

    Weisel, G. J.; Tornow, W.; Crowell, A. S.; Esterline, J. H.; Hale, G. M.; Howell, C. R.; O'Malley, P. D.; Tompkins, J. R.; Witała, H.

    2014-05-01

    We present measurements of n-d analyzing power, Ay(θ), at En=22.5 MeV. The experiment uses a shielded neutron source which produced polarized neutrons via the 2H(d⃗,n⃗)3He reaction. It also uses a deuterated liquid-scintillator center detector and six pairs of liquid-scintillator neutron side detectors. Elastic neutron scattering events are identified by using time-of-flight techniques and by setting a window in the center detector pulse-height spectrum. The beam polarization is monitored by using a high-pressure helium gas cell and an additional pair of liquid-scintillator side detectors. The n-d Ay(θ) data were corrected for finite-geometry and multiple-scattering effects using a Monte Carlo simulation of the experiment. The 22.5-MeV data demonstrate that the three-nucleon analyzing power puzzle also exists at this energy. They show a significant discrepancy with predictions of high-precision nucleon-nucleon potentials alone or combined with Tucscon-Melbourne or Urbana IX three-nucleon forces, as well as currently available effective-field theory based potentials of next-to-next-to-next-to-leading order.

  3. Reaction-in-flight neutrons as a test of stopping power in degenerate plasmas

    Science.gov (United States)

    Hayes, A. C.; Jungman, Gerard; Schulz, A. E.; Boswell, M.; Fowler, M. M.; Grim, G.; Klein, A.; Rundberg, R. S.; Wilhelmy, J. B.; Wilson, D.; Cerjan, C.; Schneider, D.; Sepke, S. M.; Tonchev, A.; Yeamans, C.

    2015-08-01

    We present the first measurements of reaction-in-flight (RIF) neutrons in an inertial confinement fusion system. The experiments were carried out at the National Ignition Facility, using both Low Foot and High Foot drives and cryogenic plastic capsules. In both cases, the high-energy RIF ( En> 15 MeV) component of the neutron spectrum was found to be about 10-4 of the total. The majority of the RIF neutrons were produced in the dense cold fuel surrounding the burning hotspot of the capsule, and the data are consistent with a compressed cold fuel that is moderately to strongly coupled (Γ˜ 0.6) and electron degenerate (θFermi/θe˜ 4). The production of RIF neutrons is controlled by the stopping power in the plasma. Thus, the current RIF measurements provide a unique test of stopping power models in an experimentally unexplored plasma regime. We find that the measured RIF data strongly constrain stopping models in warm dense plasma conditions, and some models are ruled out by our analysis of these experiments.

  4. High power communication satellites power systems study

    International Nuclear Information System (INIS)

    Josloff, A.T.; Peterson, J.R.

    1994-01-01

    This paper discusses a DOE-funded study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. This study brings together a preeminent US Industry/Russian team to cooperate on the role of high power communication satellites in the rapidly expanding communications revolution. These high power satellites play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities will be significant

  5. High resolution neutron tomography applied to tooth fillings on real teeth by use of neutron lens

    International Nuclear Information System (INIS)

    Masschaele, B.; Cauwels, P.; Mondelaers, W.; Baechler, S.; Jolie, J.; Materna, T.

    2000-01-01

    Today tomography is a well known technique for nondestructive analysis of samples. By taking several X-ray pictures from an object, it is possible to make a 3D reconstruction. The same thing can be done with neutrons. Since very recent it is possible to produce a high-flux neutron beam. By looking at the attenuation of the neutron beam in the sample from different angles, it is possible to make a neutron tomography. The properties of neutrons are so much different from X-rays that a new era in tomography has started. Where X-rays have a hard time penetrating samples containing heavy elements (Pb, Bi, U, Hg, Au), neutrons just seem to walk through. But when the neutrons encounter samples containing light compounds like water, oil, paper, B, Li,... they are easily absorbed. This makes the use of neutrons for imaging complementary to the well known X-ray imaging. The most used tooth filling material nowadays is amalgam. Amalgam is a mixture of different metals, like silver, tin, copper, mercury. Mercury is dangerous for the human body when it enters the blood stream. These fillings are very dense and X-rays have a very hard time penetrating it. Neutrons are the ideal probe for investigation of these high density regions. The result of the tomography reveals information on the long term stability of amalgam fillings and could help the still ongoing debate on the safety of the fillings. (author)

  6. Health physics aspects in disposal of self powered neutron detectors

    International Nuclear Information System (INIS)

    Deokar, D.V.; Tibrewala, S.K.; Singh, K.K.; Purohit, R.G.; Tripathi, R.M.

    2014-01-01

    Self Powered Neutron Detectors (SPNDs) are being used in reactor core for neutron flux measurement at Nuclear Power Plants. After their useful life, SPNDs are replaced and are disposed off in Tile holes. The Cobalt SPNDs having activity in the range of 35 to 160 TBq were encompassed in carbon steel canister. The canister having dose 25 to 50 Sv/h at 1 meter were transported in shielded flask for disposal in specially designed Tile hole at Solid Waste Management Facility (SWMF) at Tarapur. To keep personal exposures As Low As Reasonably Achievable (ALARA) the disposal operation was carried out remotely from a shielded cabin placed at a distance of 50 meter from the disposal site. During the disposal radiation measurements were carried out remotely by installing radiations monitors at a distance of 10 m, 25 m, and 50 m from the Tile hole. Estimations of radiation levels were carried out before jobs were taken up. Disposal of 70 numbers of Cobalt SPNDs was carried out by implementing ALARA. The decrease in collective dose is achieved due to improved operational practices, mock-up trials, effective monitoring program and safety compliance at various stages of operation

  7. Neutron-deuteron analyzing power data at 19.0 MeV

    International Nuclear Information System (INIS)

    Weisel, G. J.; Tornow, W.; Crowe, B. J. III; Crowell, A. S.; Esterline, J. H.; Howell, C. R.; Kelley, J. H.; Macri, R. A.; Pedroni, R. S.; Walter, R. L.; Witala, H.

    2010-01-01

    Measurements of neutron-deuteron (n-d) analyzing power A y (θ) at E n =19.0 MeV are reported at 16 angles from θ c.m. =46.7 to 152.0 deg. The objective of the experiment is to better characterize the discrepancies between n-d data and the predictions of three-nucleon calculations for neutron energies above 16.0 MeV. The experiment used a shielded neutron source, which produced polarized neutrons via the 2 H(d-vector,n-vector) 3 He reaction, a deuterated liquid scintillator center detector (CD) and liquid-scintillator neutron side detectors. A coincidence between the CD and the side detectors isolated the elastic-scattering events. The CD pulse height spectrum associated with each side detector was sorted by using pulse-shape discrimination, time-of-flight techniques, and by removing accidental coincidences. A Monte Carlo computer simulation of the experiment accounted for effects due to finite geometry, multiple scattering, and CD edge effects. The resulting high-precision data (with absolute uncertainties ranging from 0.0022 to 0.0132) have a somewhat lower discrepancy with the predictions of three-body calculations, as compared to those found at lower energies.

  8. Dose Evaluation of Neutron within Containment Building of a CE type Nuclear Power Plant

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Wook; Han, Jae Mun; Kim, Kyung Doek; Yun, Cheol Whan; Suh, Jang Soo; Kim, Young Jae [Nuclear Environment Technology Institute, Daejeon (Korea, Republic of)

    2005-03-15

    From measured results of the neutron fields at some principal places within the containment building in a CE type nuclear power plant in operation, the radiation exposure of a worker to the neutron at there was evaluated and the equivalent dose reflecting new recommendation (ICRP 60) was compared with that doing the old one (ICRP 26). The measured neutron field was also compared with calibration neutron field. From the analysis, the following conclusion was obtained: the average neutron radiation weighting factor according to new recommendation is 2.41 to 2.71 times higher than the old one. The average neutron radiation weighting factor at the measured place was similar to that at calibration neutron field. The average neutron energy at measured place was between 42 and 158 keV and higher than that of calibration field of 500 keV. So, the measured equivalent dose in nuclear power plant could be overestimated compared to the real equivalent dose.

  9. Calculation of the power factor using the neutron diffusion hybrid equation

    International Nuclear Information System (INIS)

    Costa da Silva, Adilson; Carvalho da Silva, Fernando; Senra Martinez, Aquilino

    2013-01-01

    Highlights: ► A neutron diffusion hybrid equation with an external neutron source was used. ► Nodal expansion method to obtain the neutron flux was used. ► Nuclear power factors in each fuel element in the reactor core were calculated. ► The results obtained were very accurate. -- Abstract: In this paper, we used a neutron diffusion hybrid equation with an external neutron source to calculate nuclear power factors in each fuel element in the reactor core. We used the nodal expansion method to obtain the neutron flux for a given control rods bank position. The results were compared with results obtained for eigenvalue problem near criticality condition and fixed source problem during the start-up of the reactor, where external neutron sources are extremely important for the stabilization of external neutron detectors.

  10. High-resolution neutron diffraction studies of biological and industrial fibres

    Energy Technology Data Exchange (ETDEWEB)

    Langan, P; Mason, S A [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Fuller, W; Forsyth, V T; Mahendrasingam, A; Shotton, M; Simpson, L [Keele Univ. (United Kingdom); Grimm, H [FZ, Juelich (Germany); Leberman, R [EMBL, (Country Unknown)

    1997-04-01

    Neutron diffraction is becoming an important tool for studying fibres due to its complementarity to X-ray diffraction. Unlike X-rays, scattering of neutrons by polymer atoms is not a function of their atomic number. In high-resolution studies (1.5-3 A) on D19 deuteration (replacing H by D) is being used to change the relative scattering power of chosen groups making them easier to locate. Recent studies on DNA and cellulose are described. (author). 6 refs.

  11. Nuclear power flies high

    International Nuclear Information System (INIS)

    Friedman, S.T.

    1983-01-01

    Nuclear power in aircraft, rockets and satellites is discussed. No nuclear-powered rockets or aircraft have ever flown, but ground tests were successful. Nuclear reactors are used in the Soviet Cosmos serles of satellites, but only one American satellite, the SNAP-10A, contained a reactor. Radioisotope thermoelectric generators, many of which use plutonium 238, have powered more than 20 satellites launched into deep space by the U.S.A

  12. New applications of neutron noise theory in power reactor physics

    Energy Technology Data Exchange (ETDEWEB)

    Arzhanov, Vasiliy

    2000-04-01

    The present thesis deals with neutron noise theory as applied to three comparatively different topics (or problems) in power reactor physics. Namely they are: theoretical investigation of the possibility to use a newly proposed current-flux (C/F) detector in Pressurized Water Reactors (PWRs) for the localisation of anomalies; both definition and studies on the point kinetic and adiabatic approximations for the relatively recently proposed Accelerator Driven Systems (ADS); development of the general theory of linear reactor kinetics and neutron noise in systems with varying size. One important practical problem is to detect and localise a vibrating control rod pin. The significance comes from the operational experience which indicates that individual pins can execute excessive mechanical vibrations that may lead to damage. Such mechanical vibrations induce neutron noise that can be detected. While the detection is relatively easy, the localisation of a vibrating control rod is much more complicated because only one measuring position is available and one needs to have at least three measured quantities. Therefore it has currently been proposed that the fluctuations of the neutron current vector, called the current noise, can be used in addition to the scalar noise in reactor diagnostic problems. The thesis investigates the possibility of the localization of a vibrating control rod pin in a PWR control assembly by using the scalar neutron noise and the 2-D radial current noise as measured at one central point in the control assembly. An explicit localisation technique is elaborated in which the searched position is determined as the absolute minimum of a minimisation function. The technique is investigated in numerical simulations. The results of the simulation tests show the potential applicability of the method. By design accelerator-driven systems would operate in a subcritical mode with a strong external source. This calls for a revision of many concepts and

  13. New applications of neutron noise theory in power reactor physics

    International Nuclear Information System (INIS)

    Arzhanov, Vasiliy

    2000-04-01

    The present thesis deals with neutron noise theory as applied to three comparatively different topics (or problems) in power reactor physics. Namely they are: theoretical investigation of the possibility to use a newly proposed current-flux (C/F) detector in Pressurized Water Reactors (PWRs) for the localisation of anomalies; both definition and studies on the point kinetic and adiabatic approximations for the relatively recently proposed Accelerator Driven Systems (ADS); development of the general theory of linear reactor kinetics and neutron noise in systems with varying size. One important practical problem is to detect and localise a vibrating control rod pin. The significance comes from the operational experience which indicates that individual pins can execute excessive mechanical vibrations that may lead to damage. Such mechanical vibrations induce neutron noise that can be detected. While the detection is relatively easy, the localisation of a vibrating control rod is much more complicated because only one measuring position is available and one needs to have at least three measured quantities. Therefore it has currently been proposed that the fluctuations of the neutron current vector, called the current noise, can be used in addition to the scalar noise in reactor diagnostic problems. The thesis investigates the possibility of the localization of a vibrating control rod pin in a PWR control assembly by using the scalar neutron noise and the 2-D radial current noise as measured at one central point in the control assembly. An explicit localisation technique is elaborated in which the searched position is determined as the absolute minimum of a minimisation function. The technique is investigated in numerical simulations. The results of the simulation tests show the potential applicability of the method. By design accelerator-driven systems would operate in a subcritical mode with a strong external source. This calls for a revision of many concepts and

  14. Pulsed power supply system for neutron well logging

    International Nuclear Information System (INIS)

    Hopkinson, E.C.

    1975-01-01

    A variable D. C. power supply and a variable A. C. power supply are coupled onto the upper end of a single conductor cable at the earth's surface and from the lower end of said cable to a well logging instrument. The A. C. voltage is used to provide filament power for the ion source accelerator tube. The D. C. voltage is used to provide power to fixed D. C. loads maintained constant by regulators once a threshold is reached. The D. C. voltage is raised above the threshold to control the pulsed acceleration voltage and hence neutron output by first feeding into a unijunction relaxation oscillator in combination with an SCR output which output is transformer coupled into a voltage multiplier circuit. An antilatch feature is provided for the SCR by transformer coupling the pulses on the SCR anode back to the base of a transistor in series with the cathode of the SCR. Two outputs of the voltage multiplier circuit are connected to the cathode and anode, respectively, of an ion source accelerator tube, the cathode being connected through a resistor to retard the ripple pulsing of the cathode to allow ionization of the accelerator tube

  15. Operational experiences of the spallation neutron source superconducting linac and power ramp-up

    International Nuclear Information System (INIS)

    Kim, Sang-Ho

    2009-01-01

    The spallation neutron source (SNS) is a second generation pulsed neutron source and designed to provide a 1-GeV, 1.44-MW proton beam to a mercury target for neutron production. Since the commissioning of the accelerator complex in 2006, the SNS has started its operation for neutron production and beam power ramp-up has been in progress toward the design goal. All subsystems of the SNS were designed and developed for substantial improvements compared to existing accelerators because the design beam power is almost an order of magnitude higher compared to existing neutron facilities and the achievable neutron scattering performance will exceed present sources by more than a factor of 20 to 100. In this paper, the operational experiences with the SNS Superconducting Linac (SCL), Power Ramp-up Plan to reach the design goal and the Power Upgrade Plan (PUP) will be presented including machine, subsystem and beam related issues.

  16. High-Energy Neutron Backgrounds for Underground Dark Matter Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu [Syracuse Univ., NY (United States)

    2016-01-01

    Direct dark matter detection experiments usually have excellent capability to distinguish nuclear recoils, expected interactions with Weakly Interacting Massive Particle (WIMP) dark matter, and electronic recoils, so that they can efficiently reject background events such as gamma-rays and charged particles. However, both WIMPs and neutrons can induce nuclear recoils. Neutrons are then the most crucial background for direct dark matter detection. It is important to understand and account for all sources of neutron backgrounds when claiming a discovery of dark matter detection or reporting limits on the WIMP-nucleon cross section. One type of neutron background that is not well understood is the cosmogenic neutrons from muons interacting with the underground cavern rock and materials surrounding a dark matter detector. The Neutron Multiplicity Meter (NMM) is a water Cherenkov detector capable of measuring the cosmogenic neutron flux at the Soudan Underground Laboratory, which has an overburden of 2090 meters water equivalent. The NMM consists of two 2.2-tonne gadolinium-doped water tanks situated atop a 20-tonne lead target. It detects a high-energy (>~ 50 MeV) neutron via moderation and capture of the multiple secondary neutrons released when the former interacts in the lead target. The multiplicity of secondary neutrons for the high-energy neutron provides a benchmark for comparison to the current Monte Carlo predictions. Combining with the Monte Carlo simulation, the muon-induced high-energy neutron flux above 50 MeV is measured to be (1.3 ± 0.2) ~ 10-9 cm-2s-1, in reasonable agreement with the model prediction. The measured multiplicity spectrum agrees well with that of Monte Carlo simulation for multiplicity below 10, but shows an excess of approximately a factor of three over Monte Carlo prediction for multiplicities ~ 10 - 20. In an effort to reduce neutron backgrounds for the dark matter experiment SuperCDMS SNO- LAB, an active neutron veto was developed

  17. Magnetic field strength of a neutron-star-powered ultraluminous X-ray source

    Science.gov (United States)

    Brightman, M.; Harrison, F. A.; Fürst, F.; Middleton, M. J.; Walton, D. J.; Stern, D.; Fabian, A. C.; Heida, M.; Barret, D.; Bachetti, M.

    2018-04-01

    Ultraluminous X-ray sources (ULXs) are bright X-ray sources in nearby galaxies not associated with the central supermassive black hole. Their luminosities imply they are powered by either an extreme accretion rate onto a compact stellar remnant, or an intermediate mass ( 100-105M⊙) black hole1. Recently detected coherent pulsations coming from three bright ULXs2-5 demonstrate that some of these sources are powered by accretion onto a neutron star, implying accretion rates significantly in excess of the Eddington limit, a high degree of geometric beaming, or both. The physical challenges associated with the high implied accretion rates can be mitigated if the neutron star surface field is very high (1014 G)6, since this suppresses the electron scattering cross-section, reducing the radiation pressure that chokes off accretion for high luminosities. Surface magnetic field strengths can be determined through cyclotron resonance scattering features7,8 produced by the transition of charged particles between quantized Landau levels. Here, we present the detection at a significance of 3.8σ of an absorption line at 4.5 keV in the Chandra spectrum of a ULX in M51. This feature is likely to be a cyclotron resonance scattering feature produced by the strong magnetic field of a neutron star. Assuming scattering off electrons, the magnetic field strength is implied to be 1011 G, while protons would imply a magnetic field of B 1015 G.

  18. Contribution to the development of numerical tools for the hardening of electronic devices to the neutronic and electromagnetic environment induced by a high power gain shot

    International Nuclear Information System (INIS)

    Gazave, J.

    2007-12-01

    When fusion ignition will be attained inside the target chambers of high energy laser facilities (LMJ-France and NIF-Usa), a harsh environment, composed of nuclear particles and an electromagnetic pulse (EMP) will be induced. All electronic devices located in the vicinity will be sensitive to this environment. In the first part of this work, a simulation method has been developed to evaluate transient currents that will be induced in coaxial cables. The relevance of this model is then discussed thanks to comparisons with experimental results. In a second part, the possibility to simulate the propagation of the EMP, inside and outside such a big structure as a target chamber, using the finite difference in time and domain (FDTD) method is evaluated. The use of a classic FDTD method is impossible for this kind of simulation because of the huge computer resources needed. It is the reason why a 3-dimensional space-time sub-grid method for FDTD has been developed and some massively parallel FDTD calculations have also been performed. (author)

  19. Feasibility study of Self Powered Neutron Detectors in Fast Reactors for detecting local change in neutron flux distribution

    International Nuclear Information System (INIS)

    Jammes, Christian; Filliatre, Philippe; Verma, Vasudha; Hellesen, Carl; Jacobsson Svard, Staffan

    2015-01-01

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor system. Diverse possibilities of detector systems installation have to be investigated with respect to practicality and feasibility according to the detection parameters. In this paper, we demonstrate the feasibility of using self powered neutron detectors as in-core detectors in fast reactors for detecting local change in neutron flux distribution. We show that the gamma contribution from fission products decay in the fuel and activation of structural materials is very small compared to the fission gammas. Thus, it is possible for the in-core SPND signal to follow changes in local neutron flux as they are proportional to each other. This implies that the signal from an in-core SPND can provide dynamic information on the neutron flux perturbations occurring inside the reactor core. (authors)

  20. Feasibility study of Self Powered Neutron Detectors in Fast Reactors for detecting local change in neutron flux distribution

    Energy Technology Data Exchange (ETDEWEB)

    Jammes, Christian; Filliatre, Philippe [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St Paul-Lez-Durance, (France); Verma, Vasudha; Hellesen, Carl; Jacobsson Svard, Staffan [Division of Applied Nuclear Physics, Uppsala University, SE-75120 Uppsala, (Sweden)

    2015-07-01

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor system. Diverse possibilities of detector systems installation have to be investigated with respect to practicality and feasibility according to the detection parameters. In this paper, we demonstrate the feasibility of using self powered neutron detectors as in-core detectors in fast reactors for detecting local change in neutron flux distribution. We show that the gamma contribution from fission products decay in the fuel and activation of structural materials is very small compared to the fission gammas. Thus, it is possible for the in-core SPND signal to follow changes in local neutron flux as they are proportional to each other. This implies that the signal from an in-core SPND can provide dynamic information on the neutron flux perturbations occurring inside the reactor core. (authors)

  1. Neutron shielding properties of a borated high-density glass

    Directory of Open Access Journals (Sweden)

    Saeed Aly Abdallah

    2017-01-01

    Full Text Available The neutron shielding properties of a borated high density glass system was characterized experimentally. The total removal macroscopic cross-section of fast neutrons, slow neutrons as well as the linear attenuation coefficient of total gamma rays, primary in addition to secondary, were measured experimentally under good geometric condition to characterize the attenuation properties of (75-x B2O3-1Li2O-5MgO-5ZnO-14Na2O-xBaO glassy system. Slabs of different thicknesses from the investigated glass system were exposed to a collimated beam of neutrons emitted from 252Cf and 241Am-Be neutron sources in order to measure the attenuation properties of fast and slow neutrons as well as total gamma rays. Results confirmed that barium borate glass was suitable for practical use in the field of radiation shielding.

  2. High Efficiency Power Converter for Low Voltage High Power Applications

    DEFF Research Database (Denmark)

    Nymand, Morten

    The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based......, and remote power generation for light towers, camper vans, boats, beacons, and buoys etc. A review of current state-of-the-art is presented. The best performing converters achieve moderately high peak efficiencies at high input voltage and medium power level. However, system dimensioning and cost are often...

  3. High power communication satellites power systems study

    Science.gov (United States)

    Josloff, Allan T.; Peterson, Jerry R.

    1995-01-01

    This paper discusses a planned study to evaluate the commercial attractiveness of high power communication satellites and assesses the attributes of both conventional photovoltaic and reactor power systems. These high power satellites can play a vital role in assuring availability of universally accessible, wide bandwidth communications, for high definition TV, super computer networks and other services. Satellites are ideally suited to provide the wide bandwidths and data rates required and are unique in the ability to provide services directly to the users. As new or relocated markets arise, satellites offer a flexibility that conventional distribution services cannot match, and it is no longer necessary to be near population centers to take advantage of the telecommunication revolution. The geopolitical implications of these substantially enhanced communications capabilities can be significant.

  4. Non-dispersive method for measuring longitudinal neutron coherence length using high frequency cold neutron pulser

    International Nuclear Information System (INIS)

    Kawai, T.; Tasaki, S.; Ebisawa, T.; Hino, M.; Yamazaki, D.; Achiwa, N.

    1999-01-01

    Complete text of publication follows. A non-dispersive method is proposed for measuring the longitudinal coherence length of a neutron using a high frequency cold neutron pulser (hf-CNP) placed between two multilayer spin splitters (MSS) which composes the cold neutron spin interferometer. Two spin eigenstates of a neutron polarized x-y plane are split non-dispersively and longitudinally in time by the hf-CNP which could reflect two components alternatively in time. The reduction of the visibility of interference fringes after being superposed by the second MSS is measured as a function of the frequency of the pulser by TOF method. From the zero visibility point obtained by extrapolation one could obtain the longitudinal coherence length of the neutron. (author)

  5. High Power Orbit Transfer Vehicle

    National Research Council Canada - National Science Library

    Gulczinski, Frank

    2003-01-01

    ... from Virginia Tech University and Aerophysics, Inc. to examine propulsion requirements for a high-power orbit transfer vehicle using thin-film voltaic solar array technologies under development by the Space Vehicles Directorate (dubbed PowerSail...

  6. A neutron calibration technique for detectors with low neutron/high photon sensitivity

    International Nuclear Information System (INIS)

    Jahr, R.; Guldbakke, S.; Cosack, M.; Dietze, G.; Klein, H.

    1978-03-01

    The neutron response of a detector with low neutron-/high photon sensitivity is given by the difference of two terms: the response to the mixed neutron-photon field, measured directly, and the response to the photons, deduced from additional measurements with a photon spectrometer. The technique is particularly suited for use in connection with targets which consist of a thick backing and thin layer of neutron producing material such as T, D, Li nuclei. Then the photon component of the mixed field is very nearly the same as the pure photon field from a 'phantom target', being identical with the neutron producing target except for the missing neutron producing material. Using this technique in connection with a T target (Ti-T-layer on silver backing) and the corresponding phantom target (Ti-layer on silver backing), a GM counter was calibrated at a neutron energy of 2.5 MeV. Possibilities are discussed to subsequently calibrate the GM counter at other neutron energies without the use of the photon spectrometer. (orig./HP) [de

  7. Neutron flux and power in RTP core-15

    Energy Technology Data Exchange (ETDEWEB)

    Rabir, Mohamad Hairie, E-mail: m-hairie@nuclearmalaysia.gov.my; Zin, Muhammad Rawi Md; Usang, Mark Dennis; Bayar, Abi Muttaqin Jalal; Hamzah, Na’im Syauqi Bin [Nuclear and reactor Physics Section, Nuclear Technology Center, Technical Support Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

    2016-01-22

    PUSPATI TRIGA Reactor achieved initial criticality on June 28, 1982. The reactor is designed to effectively implement the various fields of basic nuclear research, manpower training, and production of radioisotopes. This paper describes the reactor parameters calculation for the PUSPATI TRIGA REACTOR (RTP); focusing on the application of the developed reactor 3D model for criticality calculation, analysis of power and neutron flux distribution of TRIGA core. The 3D continuous energy Monte Carlo code MCNP was used to develop a versatile and accurate full model of the TRIGA reactor. The model represents in detailed all important components of the core with literally no physical approximation. The consistency and accuracy of the developed RTP MCNP model was established by comparing calculations to the available experimental results and TRIGLAV code calculation.

  8. Analysis of the sensitivity concept of self-powered neutron detector (SPND)

    International Nuclear Information System (INIS)

    Moreira, O.; Lescano, H.

    2012-01-01

    Self powered neutron detectors (SPND) are widely used to monitor the neutron flux, either in nuclear as in irradiation facilities and medical treatments. However, the physical meaning of the parameter that is used to relate the detector signal (an electrical current) with the neutron flux, i.e., the sensitivity of the detector, has not been sufficiently analyzed. Since the definition of sensitivity, ε=i/φ is calculated for particular reactor conditions, i.e., for thermal neutrons at room temperature, it does not take into account the deviation originated from other conditions of temperature (above ambient), as found for example in nuclear power plants. In this work we calculated the microscopic cross section weighted with the neutron flux, defined in the usual way. This weighted microscopic cross section reveals the no proportionality between the absorption rate and the neutron flux, exhibiting the problem that the SPND current signal has to properly represent the neutron flux (author)

  9. High Efficiency Power Converter for Low Voltage High Power Applications

    DEFF Research Database (Denmark)

    Nymand, Morten

    The topic of this thesis is the design of high efficiency power electronic dc-to-dc converters for high-power, low-input-voltage to high-output-voltage applications. These converters are increasingly required for emerging sustainable energy systems such as fuel cell, battery or photo voltaic based...

  10. Development of high efficiency neutron detectors

    International Nuclear Information System (INIS)

    Pickrell, M.M.; Menlove, H.O.

    1993-01-01

    The authors have designed a novel neutron detector system using conventional 3 He detector tubes and composites of polyethylene and graphite. At this time the design consists entirely of MCNP simulations of different detector configurations and materials. These detectors are applicable to low-level passive and active neutron assay systems such as the passive add-a-source and the 252 Cf shuffler. Monte Carlo simulations of these neutron detector designs achieved efficiencies of over 35% for assay chambers that can accommodate 55-gal. drums. Only slight increases in the number of detector tubes and helium pressure are required. The detectors also have reduced die-away times. Potential applications are coincident and multiplicity neutron counting for waste disposal and safeguards. The authors will present the general design philosophy, underlying physics, calculation mechanics, and results

  11. Characteristics of self-powered neutron detectors used in power reactors

    International Nuclear Information System (INIS)

    Todt, William H. Sr.

    1998-01-01

    Self-powered neutron detectors have been used effectively as in-core flux monitors for over twenty-five years in nuclear power reactors worldwide. This paper describes the basic properties of these radiation sensors including their nuclear, electrical and mechanical characteristics. Recommendations are given for the proper choice of the self-powered detector emitter to provide the proper response time and radiation sensitivity desired for use in an effective in-core radiation monitoring system. Examples are shown of specific self-powered detector designs, which are being effectively, used in in-core instrumentation systems for pressurized water, heavy water and graphite moderated light water reactors. Also examples are shown of the mechanical configurations of in-core assemblies of self-powered detectors combined with in-core thermocouples presently used in pressurized water and heavy water reactors worldwide. (author)

  12. Comparison of Thermal Neutron Flux Measured by Uranium 235 Fission Chamber and Rhodium Self-Powered Neutron Detector in MTR

    International Nuclear Information System (INIS)

    Fourmentel, D.; Filliatre, P.; Barbot, L.; Villard, J.-F.; Lyoussi, A.; Geslot, B.; Malo, J.-Y.; Carcreff, H.; Reynard-Carette, C.

    2013-06-01

    Thermal neutron flux is one of the most important nuclear parameter to be measured on-line in Material Testing Reactors (MTRs). In particular two types of sensors with different physical operating principles are commonly used: self-powered neutron detectors (SPND) and fission chambers with uranium 235 coating. This work aims to compare on one hand the thermal neutron flux evaluation given by these two types of sensors and on the other hand to compare these evaluations with activation dosimeter measurements, which are considered as the reference for absolute neutron flux assessment. This study was conducted in an irradiation experiment, called CARMEN-1, performed during 2012 in OSIRIS reactor (CEA Saclay - France). The CARMEN-1 experiment aims to improve the neutron and photon flux and nuclear heating measurements in MTRs. In this paper we focus on the thermal neutron flux measurements performed in CARMEN-1 experiment. The use of fission chambers to measure the absolute thermal neutron flux in MTRs is not very usual. An innovative calibration method for fission chambers operated in Campbell mode has been developed at the CEA Cadarache (France) and tested for the first time in the CARMEN-1 experiment. The results of these measurements are discussed, with the objective to measure with the best accuracy the thermal neutron flux in the future Jules Horowitz Reactor. (authors)

  13. Radioactively powered emission from black hole-neutron star mergers

    International Nuclear Information System (INIS)

    Tanaka, Masaomi; Wanajo, Shinya; Hotokezaka, Kenta; Kyutoku, Koutarou; Kiuchi, Kenta; Sekiguchi, Yuichiro; Shibata, Masaru

    2014-01-01

    Detection of the electromagnetic counterparts of gravitational wave (GW) sources is important to unveil the nature of compact binary coalescences. We perform three-dimensional, time-dependent, multi-frequency radiative transfer simulations for radioactively powered emission from the ejecta of black hole (BH)-neutron star (NS) mergers. Depending on the BH to NS mass ratio, spin of the BH, and equations of state of dense matter, BH-NS mergers can eject more material than NS-NS mergers. In such cases, radioactively powered emission from the BH-NS merger ejecta can be more luminous than that from NS-NS mergers. We show that, in spite of the expected larger distances to BH-NS merger events, the observed brightness of BH-NS mergers can be comparable to or even higher than that of NS-NS mergers. We find that, when the tidally disrupted BH-NS merger ejecta are confined to a small solid angle, the emission from BH-NS merger ejecta tends to be bluer than that from NS-NS merger ejecta for a given total luminosity. Thanks to this property, we might be able to distinguish BH-NS merger events from NS-NS merger events by multi-band observations of the radioactively powered emission. In addition to the GW observations, such electromagnetic observations can potentially provide independent information on the progenitors of GW sources and the nature of compact binary coalescences.

  14. Position sensitive detection of neutrons in high radiation background field.

    Science.gov (United States)

    Vavrik, D; Jakubek, J; Pospisil, S; Vacik, J

    2014-01-01

    We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high γ and e(-) radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 μm(2)) spectroscopic Timepix detector adapted for neutron detection utilizing very thin (10)B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10(-4).

  15. Rhodium self-powered neutron detector as a suitable on-line thermal neutron flux monitor in BNCT treatments.

    Science.gov (United States)

    Miller, Marcelo E; Sztejnberg, Manuel L; González, Sara J; Thorp, Silvia I; Longhino, Juan M; Estryk, Guillermo

    2011-12-01

    A rhodium self-powered neutron detector (Rh SPND) has been specifically developed by the Comisión Nacional de Energía Atómica (CNEA) of Argentina to measure locally and in real time thermal neutron fluxes in patients treated with boron neutron capture therapy (BNCT). In this work, the thermal and epithermal neutron response of the Rh SPND was evaluated by studying the detector response to two different reactor spectra. In addition, during clinical trials of the BNCT Project of the CNEA, on-line neutron flux measurements using the specially designed detector were assessed. The first calibration of the detector was done with the well-thermalized neutron spectrum of the CNEA RA-3 reactor thermal column. For this purpose, the reactor spectrum was approximated by a Maxwell-Boltzmann distribution in the thermal energy range. The second calibration was done at different positions along the central axis of a water-filled cylindrical phantom, placed in the mixed thermal-epithermal neutron beam of CNEA RA-6 reactor. In this latter case, the RA-6 neutron spectrum had been well characterized by both calculation and measurement, and it presented some marked differences with the ideal spectrum considered for SPND calibrations at RA-3. In addition, the RA-6 neutron spectrum varied with depth in the water phantom and thus the percentage of the epithermal contribution to the total neutron flux changed at each measurement location. Local (one point-position) and global (several points-positions) and thermal and mixed-field thermal neutron sensitivities were determined from these measurements. Thermal neutron flux was also measured during BNCT clinical trials within the irradiation fields incident on the patients. In order to achieve this, the detector was placed on patient's skin at dosimetric reference points for each one of the fields. System stability was adequate for this kind of measurement. Local mixed-field thermal neutron sensitivities and global thermal and mixed

  16. Rhodium self-powered neutron detector as a suitable on-line thermal neutron flux monitor in BNCT treatments

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Marcelo E.; Sztejnberg, Manuel L.; Gonzalez, Sara J.; Thorp, Silvia I.; Longhino, Juan M.; Estryk, Guillermo [Comision Nacional de Energia Atomica, Av. del Libertador 8250, Ciudad de Buenos Aires 1429 (Argentina); Comision Nacional de Energia Atomica, Av. del Libertador 8250, Ciudad de Buenos Aires 1429, Argentina and CONICET, Av. Rivadavia 1917, Ciudad de Buenos Aires 1033 (Argentina); Comision Nacional de Energia Atomica, Av. del Libertador 8250, Ciudad de Buenos Aires 1429 (Argentina)

    2011-12-15

    Purpose: A rhodium self-powered neutron detector (Rh SPND) has been specifically developed by the Comision Nacional de Energia Atomica (CNEA) of Argentina to measure locally and in real time thermal neutron fluxes in patients treated with boron neutron capture therapy (BNCT). In this work, the thermal and epithermal neutron response of the Rh SPND was evaluated by studying the detector response to two different reactor spectra. In addition, during clinical trials of the BNCT Project of the CNEA, on-line neutron flux measurements using the specially designed detector were assessed. Methods: The first calibration of the detector was done with the well-thermalized neutron spectrum of the CNEA RA-3 reactor thermal column. For this purpose, the reactor spectrum was approximated by a Maxwell-Boltzmann distribution in the thermal energy range. The second calibration was done at different positions along the central axis of a water-filled cylindrical phantom, placed in the mixed thermal-epithermal neutron beam of CNEA RA-6 reactor. In this latter case, the RA-6 neutron spectrum had been well characterized by both calculation and measurement, and it presented some marked differences with the ideal spectrum considered for SPND calibrations at RA-3. In addition, the RA-6 neutron spectrum varied with depth in the water phantom and thus the percentage of the epithermal contribution to the total neutron flux changed at each measurement location. Local (one point-position) and global (several points-positions) and thermal and mixed-field thermal neutron sensitivities were determined from these measurements. Thermal neutron flux was also measured during BNCT clinical trials within the irradiation fields incident on the patients. In order to achieve this, the detector was placed on patient's skin at dosimetric reference points for each one of the fields. System stability was adequate for this kind of measurement. Results: Local mixed-field thermal neutron sensitivities and

  17. Rhodium self-powered neutron detector as a suitable on-line thermal neutron flux monitor in BNCT treatments

    International Nuclear Information System (INIS)

    Miller, Marcelo E.; Sztejnberg, Manuel L.; Gonzalez, Sara J.; Thorp, Silvia I.; Longhino, Juan M.; Estryk, Guillermo

    2011-01-01

    Purpose: A rhodium self-powered neutron detector (Rh SPND) has been specifically developed by the Comision Nacional de Energia Atomica (CNEA) of Argentina to measure locally and in real time thermal neutron fluxes in patients treated with boron neutron capture therapy (BNCT). In this work, the thermal and epithermal neutron response of the Rh SPND was evaluated by studying the detector response to two different reactor spectra. In addition, during clinical trials of the BNCT Project of the CNEA, on-line neutron flux measurements using the specially designed detector were assessed. Methods: The first calibration of the detector was done with the well-thermalized neutron spectrum of the CNEA RA-3 reactor thermal column. For this purpose, the reactor spectrum was approximated by a Maxwell-Boltzmann distribution in the thermal energy range. The second calibration was done at different positions along the central axis of a water-filled cylindrical phantom, placed in the mixed thermal-epithermal neutron beam of CNEA RA-6 reactor. In this latter case, the RA-6 neutron spectrum had been well characterized by both calculation and measurement, and it presented some marked differences with the ideal spectrum considered for SPND calibrations at RA-3. In addition, the RA-6 neutron spectrum varied with depth in the water phantom and thus the percentage of the epithermal contribution to the total neutron flux changed at each measurement location. Local (one point-position) and global (several points-positions) and thermal and mixed-field thermal neutron sensitivities were determined from these measurements. Thermal neutron flux was also measured during BNCT clinical trials within the irradiation fields incident on the patients. In order to achieve this, the detector was placed on patient's skin at dosimetric reference points for each one of the fields. System stability was adequate for this kind of measurement. Results: Local mixed-field thermal neutron sensitivities and global

  18. High-spin structure of neutron-rich Dy isotopes

    Indian Academy of Sciences (India)

    Neutron-rich Dy isotopes; high-spin states; g-factors; cranked HFB theory. ... for 164Dy marking a clear separation in the behaviour as a function of neutron ... cipal x-axis as the cranking axis) in this mass region we have planned to make a sys-.

  19. A high pressure sample facility for neutron scattering

    International Nuclear Information System (INIS)

    Carlile, C.J.; Glossop, B.H.

    1981-06-01

    Commissioning tests involving deformation studies and tests to destruction as well as neutron diffraction measurements of a standard sample have been carried out on the SERC high pressure sample facility for neutron scattering studies. A detailed description of the pressurising equipment is given. (author)

  20. Gamma compensated pulsed ionization chamber wide range neutron/reactor power measurement system

    International Nuclear Information System (INIS)

    Ellis, W.H.

    1975-01-01

    An improved method and system of pulsed mode operation of ionization chambers is described in which a single sensor system with gamma compensation is provided by sampling, squaring, automatic gate selector, and differential amplifier circuit means, employed in relation to chambers sensitized to neutron plus gamma and gamma only to subtract out the gamma component, wherein squaring functions circuits, a supplemental high performance pulse rate system, and operational and display mode selection and sampling gate circuits are utilized to provide automatic wide range linear measurement capability for neutron flux and reactor power. Neon is employed as an additive in the ionization chambers to provide independence of ionized gas kinetics temperature effects, and the pulsed mode of operation provide independence of high temperature insulator leakage effects. (auth)

  1. Seminar Neutronika-2012. Neutron-physical problems of nuclear-power engineering. Program and abstracts

    International Nuclear Information System (INIS)

    2012-01-01

    On October, 30 - November, 2 in State Scientific Center of the Russian Federation - Institute for Physics and Power Engineering named after A.I. Leypunsky a seminar Neutron-physical problems of nuclear power engineering - Neutronika-2012 took place. On the seminar the following problems were discussed: justification of neutron-physical characteristics of reactor facilities and innovation projects; constant support of neutron-physical calculations of nuclear power installations; numerical simulation during solving reactor physics problems; simulation of neutron-physical processes in reactor facilities by Monte Carlo method; development and verification of programs for reactor facilities neutron-physical calculations; algorithms and programs for solving nonstationary problems of neutron-physical calculation of nuclear reactors; analysis of integral and reactor experiments, experimental database; justification of nuclear and radiation safety of fuel cycle [ru

  2. High power excimer laser

    International Nuclear Information System (INIS)

    Oesterlin, P.; Muckenheim, W.; Basting, D.

    1988-01-01

    Excimer lasers emitting more than 200 W output power are not commercially available. A significant increase requires new technological efforts with respect to both the gas circulation and the discharge system. The authors report how a research project has yielded a laser which emits 0.5 kW at 308 nm when being UV preionized and operated at a repetition rate of 300 Hz. The laser, which is capable of operating at 500 Hz, can be equipped with an x-ray preionization module. After completing this project 1 kW output power will be available

  3. BH3105 type neutron dose equivalent meter of high sensitivity

    International Nuclear Information System (INIS)

    Ji Changsong; Zhang Enshan; Yang Jianfeng; Zhang Hong; Huang Jiling

    1995-10-01

    It is noted that to design a neutron dose meter of high sensitivity is almost impossible in the frame of traditional designing principle--'absorption net principle'. Based on a newly proposed principle of obtaining neutron dose equi-biological effect adjustment--' absorption stick principle', a brand-new neutron dose-equivalent meter with high neutron sensitivity BH3105 has been developed. Its sensitivity reaches 10 cps/(μSv·h -1 ), which is 18∼40 times higher than one of foreign products of the same kind and is 10 4 times higher than that of domestic FJ342 neutron rem-meter. BH3105 has a measurement range from 0.1μSv/h to 1 Sv/h which is 1 or 2 orders wider than that of the other's. It has the advanced properties of gamma-resistance, energy response, orientation, etc. (6 tabs., 5 figs.)

  4. The applied research program of the High Flux Neutron Generator at the National Nuclear Center, Havana

    International Nuclear Information System (INIS)

    Perez, G.; Martin, G.; Ceballos, C.; Padron, I.; Shtejer, K.; Perez, N.; Guibert, R.; Ledo, L.M.; Cruz Inclan, Carlos

    2001-01-01

    The Havana High Flux Neutron Generator facility is an intense neutron source based on a 20 mA duoplasmatron ion source and a 250 kV high voltage power supply. It has been installed in the Neutron Generator Laboratory at the Center of Applied Technologies and Nuclear Research in 1997. This paper deal outlined the future applied program to be carried out in this facility in the next years. The Applied Research Program consists on install two nuclear analytic techniques: the PELAN technique which uses the neutron generator in the pulse mode and the Low Energy PIXE technique which uses the same facility as a low energy proton accelerator for PIXE analysis. (author)

  5. High Brightness Neutron Source for Radiography. Final report

    International Nuclear Information System (INIS)

    Cremer, J.T.; Piestrup, Melvin A.; Gary, Charles K.; Harris, Jack L.; Williams, David J.; Jones, Glenn E.; Vainionpaa, J.H.; Fuller, Michael J.; Rothbart, George H.; Kwan, J.W.; Ludewigt, B.A.; Gough, R.A.; Reijonen, Jani; Leung, Ka-Ngo

    2008-01-01

    This research and development program was designed to improve nondestructive evaluation of large mechanical objects by providing both fast and thermal neutron sources for radiography. Neutron radiography permits inspection inside objects that x-rays cannot penetrate and permits imaging of corrosion and cracks in low-density materials. Discovering of fatigue cracks and corrosion in piping without the necessity of insulation removal is possible. Neutron radiography sources can provide for the nondestructive testing interests of commercial and military aircraft, public utilities and petrochemical organizations. Three neutron prototype neutron generators were designed and fabricated based on original research done at the Lawrence Berkeley National Laboratory (LBNL). The research and development of these generators was successfully continued by LBNL and Adelphi Technology Inc. under this STTR. The original design goals of high neutron yield and generator robustness have been achieved, using new technology developed under this grant. In one prototype generator, the fast neutron yield and brightness was roughly 10 times larger than previously marketed neutron generators using the same deuterium-deuterium reaction. In another generator, we integrate a moderator with a fast neutron source, resulting in a high brightness thermal neutron generator. The moderator acts as both conventional moderator and mechanical and electrical support structure for the generator and effectively mimics a nuclear reactor. In addition to the new prototype generators, an entirely new plasma ion source for neutron production was developed. First developed by LBNL, this source uses a spiral antenna to more efficiently couple the RF radiation into the plasma, reducing the required gas pressure so that the generator head can be completely sealed, permitting the possible use of tritium gas. This also permits the generator to use the deuterium-tritium reaction to produce 14-MeV neutrons with increases

  6. Rapid response and wide range neutronic power measuring systems for fast pulsed reactors

    International Nuclear Information System (INIS)

    Sumita, Kenji; Iida, Toshiyuki; Wakayama, Naoaki.

    1976-01-01

    This paper summarizes our investigation on design principles of the rapid, stable and wide range neutronic power measuring system for fast pulsed reactors. The picoammeter, the logarithmic amplifier, the reactivity meter and the neutron current chamber are the items of investigation. In order to get a rapid response, the method of compensation for the stray capacitance of the feedback circuits and the capacitance of signal cables is applied to the picoammeter, the logarithmic amplifier and the reactivity meter with consideration for the stability margin of a whole detecting system. The response of an ionization current chamber and the method for compensating the ion component of the chamber output to get optimum responses high pass filters are investigated. Statistical fluctuations of the current chamber output are also considered in those works. The optimum thickness of the surrounding moderator of the neutron detector is also discussed from the viewpoint of the pulse shape deformation and the neutron sensitivity increase. The experimental results are reported, which were observed in the pulse operations of the one shot fast pulsed reactor ''YAYOI'' and the one shot TRIGA ''NSRR'' with the measuring systems using those principles. (auth.)

  7. High average power supercontinuum sources

    Indian Academy of Sciences (India)

    The physical mechanisms and basic experimental techniques for the creation of high average spectral power supercontinuum sources is briefly reviewed. We focus on the use of high-power ytterbium-doped fibre lasers as pump sources, and the use of highly nonlinear photonic crystal fibres as the nonlinear medium.

  8. Neutron fluctuations in accelerator driven and power reactors via backward master equations

    International Nuclear Information System (INIS)

    Zhifeng Kuang

    2000-05-01

    approach that avoids to handle complications that are unimportant for practical applications. However, from the academical point of view, it is highly desirable to establish direct contact between these two branches of neutron fluctuations in form of a unified theory from which the zero noise and the power reactor noise components can be obtained as limiting cases. Then the neglections made when considering the zero and power reactor noise separately can be estimated. Such a unified theory will also illuminate the reason for the advantage of using the Langevin approach to calculate the power reactor noise, and should be able to describe the neutron noise in intermediate cases, where neither the zero noise nor the power reactor noise dominates. The other subject of this thesis is to develop such a theory by assuming the cross section fluctuations to be a simple binary pseudo random process. Via backward master equation approach, a solution is obtained which is significantly more complicated than the cases of zero noise or power reactor noise separately, which are also given in the paper. It is shown that the general solution contains both the zero noise and the power reactor noise in the sense that they can be extracted individually as limiting cases of the general solution

  9. Epithermal neutron beam design for neutron capture therapy at the Power Burst Facility and the Brookhaven Medical Research Reactor

    International Nuclear Information System (INIS)

    Wheeler, F.J.; Parsons, D.K.; Rushton, B.L.; Nigg, D.W.

    1990-01-01

    Nuclear design studies have been performed for two reactor-based epithermal neutron beams for cancer treatment by neutron capture therapy (NCT). An intermediate-intensity epithermal beam has been designed and implemented at the Brookhaven Medical Research Reactor (BMRR). Measurements show that the BMRR design predictions for the principal characteristics of this beam are accurate. A canine program for research into the biological effects of NCT is now under way at BMRR. The design for a high-intensity epithermal beam with minimal contamination from undesirable radiation components has been finalized for the Power Burst Facility (PBF) at the Idaho National Engineering Laboratory. This design will be implemented when it is determined that human NCT trials are advisable. The PBF beam will exhibit approximately an order of magnitude improvement in absolute epithermal flux intensity over that available in the BMRR, and its angular distribution and spectral characteristics will be more advantageous for NCT. The combined effects of beam intensity, angular distribution, spectrum, and contaminant level allow the desired tumor radiation dose to be delivered in much shorter times than are possible with the currently available BMRR beam, with a significant reduction (factor of 3 to 5) in collateral dose due to beam contaminants

  10. High sensitivity neutron bursts detecting system

    International Nuclear Information System (INIS)

    Shyam, A.; Kaushik, T.C.; Srinivasan, M.; Kulkarni, L.V.

    1993-01-01

    Technique and instrumentation to detect multiplicity of fast neutrons, emitted in sharp bursts, has been developed. A bank of 16 BF 3 detectors, in an appropriate thermalising assembly, efficiency ∼ 16%, is used to detect neutron bursts. The output from this setup, through appropriate electronics, is divided into two paths. The first is directly connected to a computer controlled scalar. The second is connected to another similar scalar through a delay time unit (DTU). The DTU design is such that once it is triggered by a count pulse than it does not allow any counts to be recorded for a fixed dead time set at ∼ 100 μs. The difference in counts recorded directly and through DTU gives the total number of neutrons produced in bursts. This setup is being used to study lattice cracking, anomalous effects in solid deuterium systems and various reactor physics experiments. (author). 3 refs., 1 fig

  11. Development of a High Fluence Neutron Source for Nondestructive Characterization of Nuclear Waste

    International Nuclear Information System (INIS)

    Pickrell, Mark M.

    1999-01-01

    We are addressing the need to measure nuclear wastes, residues, and spent fuel in order to process these for final disposition. For example, TRU wastes destined for the WIPP must satisfy extensive characterization criteria outlined in the Waste Acceptance Criteria, the Quality Assurance Program Plan, and the Performance Demonstration Plan. Similar requirements exist for spent fuel and residues. At present, no nondestructive assay (NDA) instrumentation is capable of satisfying all of the PDP test cycles (particularly for Remote-Handled TRU waste). One of the primary methods for waste assay is by active neutron interrogation. The objective of this project is to improve the capability of all active neutron systems by providing a higher intensity neutron source (by about a factor of 1,000) for essentially the same cost, power, and space requirements as existing systems. This high intensity neutron source is an electrostatically confined (IEC) plasma device. The IEC is a symmetric sphere that was originally developed in the 1960s as a possible fusion reactor. It operates as DT neutron generator. Although it is not likely that this device will scale to fusion reactor levels, previous experiments1 have demonstrated a neutron yield of 2 x 1010 neutrons/second on a table-top device that can be powered from ordinary laboratory circuits (9 kilowatts). Subsequently, the IEC physics has been extensively studied at the University of Illinois and other locations. We have established theoretically the basis for scaling the output up to 1 x 1011 neutrons/second. In addition, IEC devices have run for cumulative times approaching 10,000 hours, which is essential for practical application to NDA. They have been operated in pulsed and continuous mode. The essential features of the IEC plasma neutron source, compared to existing sources of the same cost, size and power consumption, are: Table 1: Present and Target Operating Parameters for Small Neutron Generators Parameter Present IEC

  12. Calculated intensity of high-energy neutron beams

    International Nuclear Information System (INIS)

    Mustapha, B.; Nolen, J.A.; Back, B.B.

    2004-01-01

    The flux, energy and angular distributions of high-energy neutrons produced by in-flight spallation and fission of a 400 MeV/A 238 U beam and by the break-up of a 400 MeV/A deuteron beam are calculated. In both cases very intense secondary neutron beams are produced, peaking at zero degrees, with a relatively narrow energy spread. Such secondary neutron beams can be produced with the primary beams from the proposed rare isotope accelerator driver linac. The break-up of a 400 kW deuteron beam on a liquid-lithium target can produce a neutron flux of >10 10 neutrons/cm 2 /s at a distance of 10 m from the target

  13. Dosimetry Characterization of the Neutron Fields of the Intermediate Temporary Storage of the Trillo Nuclear Power Plant

    International Nuclear Information System (INIS)

    Campo Blanco, X.

    2015-01-01

    The Neutron Standards Laboratory of CIEMAT, in collaboration with the Trillo Nuclear Power Plant, has conducted a detailed dosimetric and spectrometric characterization of the neutron fields at the Intermediate Temporary Storage of the Trillo Nuclear Power Plant, as well as the neutron fields of ENSA-DPT spent fuel casks. For neutron measurements, neutron monitors and a Bonner spheres spectrometry system have been used. In addition, a Monte Carlo model of the installation and the cask has been developed and validated.

  14. Bench mark spectra for high-energy neutron dosimetry

    International Nuclear Information System (INIS)

    Dierckx, R.

    1986-01-01

    To monitor radiation damage experiments, activation detectors are commonly used. The precision of the results obtained by the multiple foil analysis is largely increased by the intercalibration in bench-mark spectra. This technique is already used in dosimetry measurements for fission reactors. To produce neutron spectra similar to fusion reactor and high-energy high-intensity neutron sources (d-Li or spallation), accelerators can be used. Some possible solutions as p-Be and d-D 2 O neutron sources, useful as bench-mark spectra are described. (author)

  15. High speed motion neutron radiography of dynamic events

    International Nuclear Information System (INIS)

    Robinson, A.H.; Barton, J.P.

    1983-01-01

    The development of a technique that permits neutron radiographic analysis of dynamic processes over a period lasting from one to ten milliseconds is described. The key to the technique is the use of a neutron pulse broad enough to span the duration of a brief event and intense enough to allow recording of the results on a high-speed movie film at frame rates of 10,000 frames/sec. Some typical application results in ballistic studies and two-phase flow are shown and discussed. The use of scintillator screens in the high-speed motion neutron radiography system is summarized and the statistical limitations of the technique are discussed

  16. High intensity proton linear accelerator for Neutron Science Project

    International Nuclear Information System (INIS)

    Mizumoto, Motoharu

    1999-01-01

    JAERI has been proposing the Neutron Science Project (NSP) which will be composed of a high intensity proton accelerator and various research facilities. With an energy of 1.5 GeV and a beam power of 8 MW, the accelerator is required for basic research fields and nuclear waste transmutation studies. The R and D work has been carried out for the components of the accelerator. In the low energy accelerator part, a beam test with an ion source and an RFQ has been performed with a current of 80 mA and a duty factor of 10% at an energy of 2 MeV. A 1 m long high power test model of DTL has been fabricated and tested with a duty factor of 20%. In the high energy accelerator part, a superconducting (SC) linac has been selected as a main option from 100 MeV to 1.5 GeV. A test stand for SC linac cavity with equipment of cryogenics, vacuum, RF source and cavity processing and cleaning system has been prepared to test the fabrication process and physics issues. The vertical tests of β = 0.5 (145 MeV) and β = 0.89 (1.1 GeV) single cell SC cavities have been made resulting in a maximum electric field strength of 44 MV/m and 47 MV/m at 2 K, respectively. (author)

  17. High-quality single crystals for neutron experiments

    Indian Academy of Sciences (India)

    studies and our collaborative research projects with other UK and international groups will be discussed. Keywords. Crystal growth; floating zone method; neutron scattering. ... of single crystals of new materials is a highly competitive business.

  18. A combined system for the generation of an intense cold neutron beam with a medium power research reactor

    International Nuclear Information System (INIS)

    Utsuro, M.; Okumura, K.

    1989-01-01

    A system consisting of a very cold moderator and a neutron-accelerating high speed turbine is proposed for the intensification of a cold neutron beam in a medium power research reactor up to the level applicable to inelastic neutron scattering spectrometers. A numerical result for 5 cm thick solid ortho-deuterium at a temperature of about 4 K and a turbine with a blade velocity of about 350 m/s gives an output intensity of monochromatic neutrons of about 10 7 n/cm 2 at an energy of about 3.5 meV with an energy width of about 0.2 meV for a typical case of a 5 MW reactor. (orig.)

  19. Recent high-accuracy measurements of the 1S0 neutron-neutron scattering length

    International Nuclear Information System (INIS)

    Howell, C.R.; Chen, Q.; Gonzalez Trotter, D.E.; Salinas, F.; Crowell, A.S.; Roper, C.D.; Tornow, W.; Walter, R.L.; Carman, T.S.; Hussein, A.; Gibbs, W.R.; Gibson, B.F.; Morris, C.; Obst, A.; Sterbenz, S.; Whitton, M.; Mertens, G.; Moore, C.F.; Whiteley, C.R.; Pasyuk, E.; Slaus, I.; Tang, H.; Zhou, Z.; Gloeckle, W.; Witala, H.

    2000-01-01

    This paper reports two recent high-accuracy determinations of the 1 S 0 neutron-neutron scattering length, a nn . One was done at the Los Alamos National Laboratory using the π - d capture reaction to produce two neutrons with low relative momentum. The neutron-deuteron (nd) breakup reaction was used in other measurement, which was conducted at the Triangle Universities Nuclear Laboratory. The results from the two determinations were consistent with each other and with previous values obtained using the π - d capture reaction. The value obtained from the nd breakup measurements is a nn = -18.7 ± 0.1 (statistical) ± 0.6 (systematic) fm, and the value from the π - d capture experiment is a nn = -18.50 ± 0.05 ± 0.53 fm. The recommended value is a nn = -18.5 ± 0.3 fm. (author)

  20. Thermal neutron scattering studies of condensed matter under high pressures

    International Nuclear Information System (INIS)

    Carlile, C.J.; Salter, D.C.

    1978-01-01

    Although temperature has been used as a thermodynamic variable for samples in thermal neutron scattering experiments since the inception of the neutron technique, it is only in the last decade that high pressures have been utilised for this purpose. In the paper the problems particular to this field of work are outlined and a review is made of the types of high-pressure cells used and the scientific results obtained from the experiments. 103 references. (author)

  1. Discrimination of neutrons and gamma quanta with the aid of their power density spectra

    International Nuclear Information System (INIS)

    Buchmueller, R.

    1977-01-01

    The paper introduces a method of using only one fission chamber to discriminate the neutron flux against the gamma flux. The gamma chamber current may be several orders of magnitude higher than the neutron chamber current. In specially dimensioned fission chambers the neutrons and gamma quanta are made to generate different current pulses. Discrimination becomes possible by recording the power density spectrum of the mixture of pulses over a broad frequency range ( [de

  2. A two-dimensional simulator of the neutronic behaviour of low power fast reactors

    International Nuclear Information System (INIS)

    Penha, M.A.V.R. da.

    1984-01-01

    A model to simulate the temporal neutronic behaviour of fast breeder reactors was developed. The effective cross-sections are corrected, whenever the reactor state change; by using linear correlations and interpolation schemes with data contained in a library previously compiled. This methodology was coupled with a simplified spatial neutronic calculation to investigate the temporal behaviour of neutronic parameters such as breeding gain, flux and power. (Author) [pt

  3. High-flux neutron source based on a liquid-lithium target

    Science.gov (United States)

    Halfon, S.; Feinberg, G.; Paul, M.; Arenshtam, A.; Berkovits, D.; Kijel, D.; Nagler, A.; Eliyahu, I.; Silverman, I.

    2013-04-01

    A prototype compact Liquid Lithium Target (LiLiT), able to constitute an accelerator-based intense neutron source, was built. The neutron source is intended for nuclear astrophysical research, boron neutron capture therapy (BNCT) in hospitals and material studies for fusion reactors. The LiLiT setup is presently being commissioned at Soreq Nuclear research Center (SNRC). The lithium target will produce neutrons through the 7Li(p,n)7Be reaction and it will overcome the major problem of removing the thermal power generated by a high-intensity proton beam, necessary for intense neutron flux for the above applications. The liquid-lithium loop of LiLiT is designed to generate a stable lithium jet at high velocity on a concave supporting wall with free surface toward the incident proton beam (up to 10 kW). During off-line tests, liquid lithium was flown through the loop and generated a stable jet at velocity higher than 5 m/s on the concave supporting wall. The target is now under extensive test program using a high-power electron-gun. Up to 2 kW electron beam was applied on the lithium flow at velocity of 4 m/s without any flow instabilities or excessive evaporation. High-intensity proton beam irradiation will take place at SARAF (Soreq Applied Research Accelerator Facility) superconducting linear accelerator currently in commissioning at SNRC.

  4. Characteristics of self-powered neutron detectors used in power reactors

    International Nuclear Information System (INIS)

    Todt, W.H.

    1997-01-01

    Self-Powered Neutron Detectors have been used effectively as in-core flux monitors for over twenty-five years in nuclear power reactors world-wide. The basic properties of these radiation sensors are described including their nuclear, electrical and mechanical characteristics. Recommendations are given for the proper choice of the self-powered detector emitter to provide the proper response time and radiation sensitivity desired for use in an effective in-core radiation monitoring system. Examples are shown of specific self-powered detector designs which are being effectively used in in-core instrumentation systems for pressurised water, heavy water and graphite moderated light water reactors. Examples are also shown of the mechanical configurations of in-core assemblies of self-powered detectors combined with in-core thermocouples presently used in pressurised water and heavy water reactors worldwide. This paper is a summary of a new IEC standard to be issued in 1996 describing the characteristics and test methods of self-powered detectors used in nuclear power reactors. (author)

  5. High-powered manoeuvres

    CERN Multimedia

    Anaïs Schaeffer

    2013-01-01

    This week, CERN received the latest new transformers for the SPS. Stored in pairs in 24-tonne steel containers, these transformers will replace the old models, which have been in place since 1981.     The transformers arrive at SPS's access point 4 (BA 4). During LS1, the TE-EPC Group will be replacing all of the transformers for the main converters of the SPS. This renewal campaign is being carried out as part of the accelerator consolidation programme, which began at the start of April and will come to an end in November. It involves 80 transformers: 64 with a power of 2.6 megavolt-amperes (MVA) for the dipole magnets, and 16 with 1.9 MVA for the quadrupoles. These new transformers were manufactured by an Italian company and are being installed outside the six access points of the SPS by the EN-HE Group, using CERN's 220-tonne crane. They will contribute to the upgrade of the SPS, which should thus continue to operate as the injector for the LHC until 2040....

  6. Neutron activation analysis of geological samples for gold and accessory elements power reactor

    International Nuclear Information System (INIS)

    Burmistrenko, Yu.N.; Medvedev, A.A.; Kovalenko, V.V.; Markov, A.V.

    1986-01-01

    Possibility of using a power reactor for neutron activation analysis to detect gold and accompanying elements in geological samples of a region was investigated. Specimens (gold-containing samples and standards) were irradiated in a spare channel for ionization chambers located outside the core in graphite reflector. Spectrometry was conducted with the help of a semiconducting detector with LP 4900 multichannel analizer. Sensitivity threshold for gold was (1-3)10 -6 % - (1-2)10 -5 %. It is shown that this method can be used not only for gold detection but for high-sensitive multielement analysis of geological samples

  7. Recent developments on micrometric fission chambers for high neutron fluxes

    International Nuclear Information System (INIS)

    Letourneau, A.; Bringer, O.; Dupont, E.; Marie, F.; Panebianco, S.; Toussaint, J. C.; Veyssiere, C.; Chabod, S.; Breaud, S.; Oriol, L.

    2009-01-01

    With the development of innovative nuclear systems and new generation neutron sources, the nuclear instrumentation should be adapted. Since several years, we developed microscopic fission chambers to study the transmutation of minor actinides in high thermal-neutron fluxes. The recent developments done to fulfill the drastic conditions of irradiations are described in this paper together with the feedback from the measurements. Two installations were used: the HFR of the ILL for its highest thermal neutron flux of the world and the MEGAPIE target which was the first 1 MW liquid Pb-Bi spallation target in the world. (authors)

  8. Recent developments on micrometric fission chambers for high neutron fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Letourneau, A. [Irfu, Service de Physique Nucleaire, CEA-Saclay, 91191 Gif-sur-Yvette (France); Bringer, O.; Dupont, E.; Marie, F.; Panebianco, S.; Toussaint, J. C.; Veyssiere, C. [Irfu, CEA-Saclay, 91191 Gif-sur-Yvette (France); Chabod, S. [LPSC, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3 (France); Breaud, S.; Oriol, L. [DEN/DER/SPEX, CEA-Cadarache, Saint-Paul-lez-Durances (France)

    2009-07-01

    With the development of innovative nuclear systems and new generation neutron sources, the nuclear instrumentation should be adapted. Since several years, we developed microscopic fission chambers to study the transmutation of minor actinides in high thermal-neutron fluxes. The recent developments done to fulfill the drastic conditions of irradiations are described in this paper together with the feedback from the measurements. Two installations were used: the HFR of the ILL for its highest thermal neutron flux of the world and the MEGAPIE target which was the first 1 MW liquid Pb-Bi spallation target in the world. (authors)

  9. LOS ALAMOS NEUTRON SCIENCE CENTER CONTRIBUTIONS TO THE DEVELOPMENT OF FUTURE POWER REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    GAVRON, VICTOR I. [Los Alamos National Laboratory; HILL, TONY S. [Los Alamos National Laboratory; PITCHER, ERIC J. [Los Alamos National Laboratory; TOVESSON, FREDERIK K. [Los Alamos National Laboratory

    2007-01-09

    measurements in progress include {sup 240}Pu and {sup 242}Pu. The United States recently announced the Global Nuclear Energy Partnership (GNEP), with the goal of closing the commercial nuclear fuel cycle while minimizing proliferation risk. GNEP achieves these goals using fast-spectrum nuclear reactors powered by new transmutation fuels that contain significant quantities of minor actinides. The proposed Materials Test Station (MTS) will provide the GNEP with a cost-effective means of obtaining domestic fast-spectrum irradiations of advanced transmutation fuel forms and structural materials, which is an important step in the fuels qualification process. The MTS will be located at the LANSCE, and will be driven by a 1.08-MW proton beam. Th epeak neutron flux in the irradiation region is 1.67 x 10{sup 15} n/cm{sup 2}/s, and the energy spectrum is similar to that of a fast reactor, with the addition of a high-energy tail. The facility is expected to operate at least 4,400 hours per year. Fuel burnup rates will exceed 4% per year, and the radiation damage rate in iron will be 18 dpa (displacements per atom) per year. The construction cost is estimated to be $73M (including 25% contingency), with annual operating costs in the range of $6M to $10M. Appropriately funded, the MTS could begin operation in 2010.

  10. Autonomously managed high power systems

    International Nuclear Information System (INIS)

    Weeks, D.J.; Bechtel, R.T.

    1985-01-01

    The need for autonomous power management capabilities will increase as the power levels of spacecraft increase into the multi-100 kW range. The quantity of labor intensive ground and crew support consumed by the 9 kW Skylab cannot be afforded in support of a 75-300 kW Space Station or high power earth orbital and interplanetary spacecraft. Marshall Space Flight Center is managing a program to develop necessary technologies for high power system autonomous management. To date a reference electrical power system and automation approaches have been defined. A test facility for evaluation and verification of management algorithms and hardware has been designed with the first of the three power channel capability nearing completion

  11. Self-powered neutron and γ-ray flux detector

    International Nuclear Information System (INIS)

    Allan, C.J.

    1983-01-01

    According to the invention there is provided a self-powered neutron and γ-ray flux detector, comprising: a) an emitter core wire; b) an emitter outer layer around the core wire and of different metal thereto; c) a metal collector around the emitter core wire and the emitter outer layer; and d) dielectric insulation electrically insulating the emitter core wire and the emitter outer layer from the metal collector. The improvement comprises: a) the overall diameter of the emitter core wire and the emitter outer layer is at least of the order of 0.4 mm in diameter; b) the emitter outer layer covers only of the order of l0 percent of the order of 90 percent of the emitter core wire surface area and comprises at least one band around the emitter core wire and is of a thickness in the range of the order 0.02 mm to of the order of 0.07 mm; and c) the metal of the emitter core wire, the metal of the emitter outer layer, the metal of the metal collector, the overall diameter of the emitter core wire and the emitter outer layer and the surface area of the emitter core wire that is covered by the emitter outer layer are selected so that the detector has a prompt fraction in the range of the order of 90 percent to of the order of 96 percent and has a dynamic response which substantially matches the dynamic response of the power in the fuel of the nuclear reactor in which the detector is to be used

  12. Neutron shielding properties of a new high-density concrete

    International Nuclear Information System (INIS)

    Lorente, A.; Gallego, E.; Vega Carrillo, H.R.; Mendez, R.

    2008-01-01

    The neutron shielding properties of a new high-density concrete (commercially available under the name Hormirad TM , developed in Spain by the company CT-RAD) have been characterized both experimentally and by Monte Carlo calculations. The shielding properties of this concrete against photons were previously studied and the material is being used to build bunkers, mazes and doors in medical accelerator facilities with good overall results. In this work, the objective was to characterize the material behaviour against neutrons, as well as to test alternative mixings including boron compounds in an effort to improve neutron shielding efficiency. With that purpose, Hormirad TM slabs of different thicknesses were exposed to an 241 Am-Be neutron source under controlled conditions in the neutron measurements laboratory of the Nuclear Engineering Department at UPM. The original mix, which includes a high fraction of magnetite, was then modified by adding different proportions of anhydrous borax (Na 2 B 4 O 7 ). In order to have a reference against common concrete used to shield medical accelerator facilities, the same experiment was repeated with ordinary (HA-25) concrete slabs. In parallel to the experiments, Monte Carlo calculations of the experiments were performed with MCNP5. The experimental results agree reasonably well with the Monte Carlo calculations. Therefore, the first and equilibrium tenth-value layers have been determined for the different types of concrete tested. The results show an advantageous behaviour of the Hormirad TM concrete, in terms of neutron attenuation against real thickness of the shielding. Borated concretes seem less practical since they did not show better neutron attenuation with respect to real thickness and their structural properties are worse. The neutron attenuation properties of Hormirad TM for typical neutron spectra in clinical LINAC accelerators rooms have been also characterized by Monte Carlo calculation. (author)

  13. High-performance instruments in neutron arena of JHP. Preliminary version

    International Nuclear Information System (INIS)

    Furusaka, M.; Itoh, S.; Otomo, T.; Arai, M.

    1996-05-01

    This report is a preliminary report of high-performance instruments in neutron arena of JHP (Japan Hadron Project). This report consists of as follows; neutron intensity of neutron arena, development of neutron sources in neutron arena, experimental devices and instrumentation. (J.P.N.)

  14. High Fidelity Ion Beam Simulation of High Dose Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Was, Gary; Wirth, Brian; Motta, Athur; Morgan, Dane; Kaoumi, Djamel; Hosemann, Peter; Odette, Robert

    2018-04-30

    Project Objective: The objective of this proposal is to demonstrate the capability to predict the evolution of microstructure and properties of structural materials in-reactor and at high doses, using ion irradiation as a surrogate for reactor irradiations. “Properties” includes both physical properties (irradiated microstructure) and the mechanical properties of the material. Demonstration of the capability to predict properties has two components. One is ion irradiation of a set of alloys to yield an irradiated microstructure and corresponding mechanical behavior that are substantially the same as results from neutron exposure in the appropriate reactor environment. Second is the capability to predict the irradiated microstructure and corresponding mechanical behavior on the basis of improved models, validated against both ion and reactor irradiations and verified against ion irradiations. Taken together, achievement of these objectives will yield an enhanced capability for simulating the behavior of materials in reactor irradiations

  15. Neutron powder diffraction under high pressure at J-PARC

    International Nuclear Information System (INIS)

    Utsumi, Wataru; Kagi, Hiroyuki; Komatsu, Kazuki; Arima, Hiroshi; Nagai, Takaya; Okuchi, Takuo; Kamiyama, Takashi; Uwatoko, Yoshiya; Matsubayashi, Kazuyuki; Yagi, Takehiko

    2009-01-01

    It is expected that high-pressure material science and the investigation of the Earth's interior will progress greatly using the high-flux pulse neutrons of J-PARC. In this article, we introduce our plans for in situ neutron powder diffraction experiments under high pressure at J-PARC. The use of three different types of high-pressure devices is planned; a Paris-Edinburgh cell, a new opposed-anvil cell with a nano-polycrystalline diamond, and a cubic anvil high-pressure apparatus. These devices will be brought to the neutron powder diffraction beamlines to conduct a 'day-one' high-pressure experiment. For the next stage of research, we propose construction of a dedicated beamline for high-pressure material science. Its conceptual designs are also introduced here.

  16. Future directions in high-pressure neutron diffraction

    Science.gov (United States)

    Guthrie, M.

    2015-04-01

    The ability to manipulate structure and properties using pressure has been well known for many centuries. Diffraction provides the unique ability to observe these structural changes in fine detail on lengthscales spanning atomic to nanometre dimensions. Amongst the broad suite of diffraction tools available today, neutrons provide unique capabilities of fundamental importance. However, to date, the growth of neutron diffraction under extremes of pressure has been limited by the weakness of available sources. In recent years, substantial government investments have led to the construction of a new generation of neutron sources while existing facilities have been revitalized by upgrades. The timely convergence of these bright facilities with new pressure-cell technologies suggests that the field of high-pressure (HP) neutron science is on the cusp of substantial growth. Here, the history of HP neutron research is examined with the hope of gleaning an accurate prediction of where some of these revolutionary capabilities will lead in the near future. In particular, a dramatic expansion of current pressure-temperature range is likely, with corresponding increased scope for extreme-conditions science with neutron diffraction. This increase in coverage will be matched with improvements in data quality. Furthermore, we can also expect broad new capabilities beyond diffraction, including in neutron imaging, small angle scattering and inelastic spectroscopy.

  17. Results and interpretation of noise measurements using in-core self powered neutron detector strings at Unit 2 of the Paks Nuclear Power Plant

    International Nuclear Information System (INIS)

    Gloeckler, O.; Por, G.; Valko, J.

    1986-11-01

    In-core neutron noise and fuel assembly outlet temperature noise measurements were performed at Unit 2 of Paks Nuclear Power Plant. Characteristics of the reactor and the noise measuring equipment are briefly described. The in-core Rhodium emitter selfpowered neutron detector strings positioned axially above the other show high coherence and linear phase at low frequencies indicating a marked transport effect, not regularly measured in PWRs. The coherence between horizontally placed neutron detectors is small and the phase is zero. A transport effect of different nature is obtained between neutron detectors (in-core and ex-core) and fuel assembly outlet thermocouples. The observed characteristics depend on reactor and fuel assembly power in a way supporting interpretation in terms of coolant density and void content changes and power feedback effects. During routine analysis vibration of 1.1 Hz appeared as a strong peak in the power spectra. The control assembly that was responsible for the observed behaviour could be localized with high certainty. (author)

  18. Solid State Power Amplifier for 805 MegaHertz at the Los Alamos Neutron Science Center

    International Nuclear Information System (INIS)

    Davis, J.L.; Lyles, J.T.M.

    1998-01-01

    Particle accelerators for protons, electrons, and other ion species often use high-power vacuum tubes for RF amplification, due to the high RF power requirements to accelerate these particles with high beam currents. The final power amplifier stages driving large accelerators are unable to be converted to solid-state devices with the present technology. In some instances, radiation levels preclude the use of transistors near beamlines. Work is being done worldwide to replace the RF power stages under about ten kilowatts CW with transistor amplifiers, due to the lower maintenance costs and obsolescence of power tubes in these ranges. This is especially practical where the stages drive fifty Ohm impedance and are not located in high radiation zones. The authors are doing this at the Los Alamos Neutron Science Center (LANSCE) proton linear accelerator (linac) in New Mexico. They replaced a physically-large air-cooled UHF power amplifier using a tetrode electron tube with a compact water-cooled unit based on modular amplifier pallets developed at LANSCE. Each module uses eight push-pull bipolar power transistor pairs operated in class AB. Four pallets can easily provide up to 2,800 watts of continuous RF at 805 MHz. A radial splitter and combiner parallels the modules. This amplifier has proven to be completely reliable after over 10,000 hours of operation without failure. A second unit was constructed and installed for redundancy, and the old tetrode system was removed in 1998. The compact packaging for cooling, DC power, impedance matching, RF interconnection, and power combining met the electrical and mechanical requirements. CRT display of individual collector currents and RF levels is made possible with built-in samplers and a VXI data acquisition unit

  19. Proton induction linacs as high-intensity neutron sources

    International Nuclear Information System (INIS)

    Keefe, D.; Hoyer, E.

    1981-01-01

    Proton induction linacs are explored as high intensity neutron sources. The induction linac - concept, properties, experience with electrons, and possibilities - and its limitations for accelerating ions are reviewed. A number of proton induction linac designs are examined with the LIACEP program and general conclusions are given. Results suggest that a proton induction accelerator of the lowest voltage, consistent with good neutron flux, is preferred and could well be cost competitive with the usual rf linac/storage ring designs. (orig.)

  20. High yield neutron generators using the DD reaction

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, J. H.; Harris, J. L.; Piestrup, M. A.; Gary, C. K.; Williams, D. L.; Apodaca, M. D.; Cremer, J. T. [Adelphi technology, 2003 E. Bayshore Rd. 94061, Redwood City, CA (United States); Ji, Qing; Ludewigt, B. A. [Lawrence Berkeley National Lab, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Jones, G. [G and J Enterprise, 1258 Quary Ln, Suite F, Pleasanton California 94566 (United States)

    2013-04-19

    A product line of high yield neutron generators has been developed at Adelphi technology inc. The generators use the D-D fusion reaction and are driven by an ion beam supplied by a microwave ion source. Yields of up to 5 Multiplication-Sign 10{sup 9} n/s have been achieved, which are comparable to those obtained using the more efficient D-T reaction. The microwave-driven plasma uses the electron cyclotron resonance (ECR) to produce a high plasma density for high current and high atomic ion species. These generators have an actively pumped vacuum system that allows operation at reduced pressure in the target chamber, increasing the overall system reliability. Since no radioactive tritium is used, the generators can be easily serviced, and components can be easily replaced, providing essentially an unlimited lifetime. Fast neutron source size can be adjusted by selecting the aperture and target geometries according to customer specifications. Pulsed and continuous operation has been demonstrated. Minimum pulse lengths of 50 {mu}s have been achieved. Since the generators are easily serviceable, they offer a long lifetime neutron generator for laboratories and commercial systems requiring continuous operation. Several of the generators have been enclosed in radiation shielding/moderator structures designed for customer specifications. These generators have been proven to be useful for prompt gamma neutron activation analysis (PGNAA), neutron activation analysis (NAA) and fast neutron radiography. Thus these generators make excellent fast, epithermal and thermal neutron sources for laboratories and industrial applications that require neutrons with safe operation, small footprint, low cost and small regulatory burden.

  1. Study of a high spatial resolution {sup 10}B-based thermal neutron detector for application in neutron reflectometry: the Multi-Blade prototype

    Energy Technology Data Exchange (ETDEWEB)

    Piscitelli, F; Buffet, J C; Clergeau, J F; Cuccaro, S; Guérard, B; Khaplanov, A; Manna, Q La; Rigal, J M; Esch, P Van, E-mail: piscitelli@ill.fr [Institut Laue-Langevin (ILL), 6, Jules Horowitz, 38042, Grenoble (France)

    2014-03-01

    Although for large area detectors it is crucial to find an alternative to detect thermal neutrons because of the {sup 3}He shortage, this is not the case for small area detectors. Neutron scattering science is still growing its instruments' power and the neutron flux a detector must tolerate is increasing. For small area detectors the main effort is to expand the detectors' performances. At Institut Laue-Langevin (ILL) we developed the Multi-Blade detector which wants to increase the spatial resolution of {sup 3}He-based detectors for high flux applications. We developed a high spatial resolution prototype suitable for neutron reflectometry instruments. It exploits solid {sup 10}B-films employed in a proportional gas chamber. Two prototypes have been constructed at ILL and the results obtained on our monochromatic test beam line are presented here.

  2. Comparison of dynamic compensation methods for delayed self-powered neutron detector

    International Nuclear Information System (INIS)

    In, Wang Kee; Kim, Joon Sung; Auh, Geun Sun; Yoon, Tae Young

    1993-01-01

    Dynamic compensation methods for rhodium self-powered neutron detector have been developed by Banda and Hoppe to compensate for the time delay associated with detector signals. The time delay is due to the decay of the neutron-activated rhodium and results in delayed detector response. Two digital dynamic compensation methods, were compared for step change of neutron flux in this paper. The inverse kinetics method gave slightly better response time and noise gain. However, the inverse kinetics method also showed overshooting of neutron flux for the step change. (Author)

  3. Visualization of neutron flux and power distributions in TRIGA Mark II reactor as an educational tool

    International Nuclear Information System (INIS)

    Snoj, Luka; Ravnik, Matjaz; Lengar, Igor

    2008-01-01

    Modern Monte Carlo computer codes (e.g. MCNP) for neutron transport allow calculation of detailed neutron flux and power distribution in complex geometries with resolution of ∼1 mm. Moreover they enable the calculation of individual particle tracks, scattering and absorption events. With the use of advanced software for 3D visualization (e.g. Amira, Voxler, etc.) one can create and present neutron flux and power distribution in a 'user friendly' way convenient for educational purposes. One can view axial, radial or any other spatial distribution of the neutron flux and power distribution in a nuclear reactor from various perspectives and in various modalities of presentation. By visualizing the distribution of scattering and absorption events and individual particle tracks one can visualize neutron transport parameters (mean free path, diffusion length, macroscopic cross section, up-scattering, thermalization, etc.) from elementary point of view. Most of the people remember better, if they visualize the processes. Therefore the representation of the reactor and neutron transport parameters is a convenient modern educational tool for the (nuclear power plant) operators, nuclear engineers, students and specialists involved in reactor operation and design. The visualization of neutron flux and power distributions in Jozef Stefan Institute TRIGA Mark II research reactor is treated in the paper. The distributions are calculated with MCNP computer code and presented using Amira and Voxler software. The results in the form of figures are presented in the paper together with comments qualitatively explaining the figures. (authors)

  4. Application of neutron absorption method of the analysis on thermal neutrons for the control of substances and products containing boron in a nuclear power engineering and industry

    International Nuclear Information System (INIS)

    Chuev, A.G.; Kiryanov, G.I.; Shagov, S.V.; Shtan, A.S.; Titov, V.V.

    2002-01-01

    Nuclear physical methods of analysis using the absorption effect of ionising radiation should satisfy the following requirements for industrial practice. First, the ionising radiation should have a high penetrating ability in the environment examined to ensure a representative nature of the data and reliability of the analysis. Secondly, the absorption degree of radiation should be sufficient to maintain the sensitivity and accuracy of the measurements. In addition, to keep the necessary selectivity, the neutron absorption analysis on thermal neutrons is applied on chemical elements and their isotopes with an anomalously high absorption cross section about 10 2 - 10 4 barn. To such elements belong Gd, Sm, B, Cd, Hg and others. Based on the exponential law of absorption for thermal neutrons, an analytical expression was obtained for the concentration of the element analyzed in dependence on the flow of the elapsed neutrons. A number of interfering factors such as the matrix effect of the filling agent, scattering of neutrons, dispersion of the density and of the temperature of the environment, and background radiation have to be taken into account. Owing to the difference between the experimental calibration dependence and the exponential one, the methods of its mathematical approximation, for example, polynomial function and partially hyperbolic one are considered. The scheme realisation of the method is feasible in geometry 'on passage' and 'on reflection' of the neutron flow. Radionuclide Pu-Be sources are preferred as the neutron sources based on nuclear reactions of the (α,n) type. Detectors used for registration of slow neutrons are gas discharge corona 3 He-filled counters. Hydrogen-containing substances with good scattering properties are utilised as the fast neutron moderators. The neutron absorption method has found wide application in the nuclear power engineering and atomic industry. This method is intended for continuous automatic monitoring of

  5. Theory of Pulsed Neutron Experiments in Highly Heterogeneous Multiplying Media

    International Nuclear Information System (INIS)

    Corno, S.E.

    1965-01-01

    In this work we investigate the time and space dependence of the neutron flux within a highly heterogeneous assembly, in which pulsed or sinusoidally modulated neutrons are injected. We consider, for the sake of simplicity, a device consisting of a cylindrical block of heavy moderator, along the axis of which a line-shaped region of fissionable material is located. The driving neutron source is assumed to be located on one of the end faces of the cylinder. The extent of the fissionable region allows us to deal with it as with an absorbing and multiplying singularity of the neutron field. As our attention is mostly concentrated on space and time variation of the neutron flux, rather crude approximations are assumed as far as the energy dependence of the neutron population is concerned. Within the limits of the age-diffusion theory, the response of the device to any neutron excitation may be found in closed form. For a sinusoidally modulated source of given frequency, it may easily be shown that, if the axial singularity were a purely absorbing one, the neutron waves being propagated along the device would possess a phase shift; a wavelength and an attenuation constant depending on the absorbing properties of the singularity. This picture becomes more and more complicated when neutron multiplication occurs. For this general case the solution derived in our paper obviously turns out to be dependent on both absorption and multiplication properties of the singularity. This circumstance suggests, among others, the idea of using a device of the type described above for testing fuel elements of heterogeneous reactors. (author) [fr

  6. EURISOL High Power Targets

    CERN Document Server

    Kadi, Y; Lindroos, M; Ridikas, D; Stora, T; Tecchio, L; CERN. Geneva. BE Department

    2009-01-01

    Modern Nuclear Physics requires access to higher yields of rare isotopes, that relies on further development of the In-flight and Isotope Separation On-Line (ISOL) production methods. The limits of the In-Flight method will be applied via the next generation facilities FAIR in Germany, RIKEN in Japan and RIBF in the USA. The ISOL method will be explored at facilities including ISAC-TRIUMF in Canada, SPIRAL-2 in France, SPES in Italy, ISOLDE at CERN and eventually at the very ambitious multi-MW EURISOL facility. ISOL and in-flight facilities are complementary entities. While in-flight facilities excel in the production of very short lived radioisotopes independently of their chemical nature, ISOL facilities provide high Radioisotope Beam (RIB) intensities and excellent beam quality for 70 elements. Both production schemes are opening vast and rich fields of nuclear physics research. In this article we will introduce the targets planned for the EURISOL facility and highlight some of the technical and safety cha...

  7. Power Burst Reactor Facility as an epithermal neutron source for brain cancer therapy

    International Nuclear Information System (INIS)

    Wheeler, F.J.

    1986-01-01

    The Power Burst Facility (PBF) reactor is considered for modification to provide an intense, clean source of intermediate-energy (epithermal) neutrons desirable for clinical studies of neutron capture therapy (NCT) for malignant tumors. The modifications include partial replacement of the reflector, installation of a neutron-moderating, shifting region, additional shielding, and penetration of the present concrete shield with a collimating (and optionally) filtering region. The studies have indicated that the reactor, after these modifications, will be safely operable at full power (28 MW) within the acceptable limits of the plant protection systems. The neutron beam exiting from the collimator port is predicted to be of sufficient intensity (approx.10 10 neutrons/cm 2 -s) to provide therapeutic doses in very short irradiation times. The beam would be relatively free of undesirable fast neutrons, thermal neutrons and gamma rays. The calculated neutron energy spectrum and associated gamma rays in the beam were provided as input in simulation studies that used a computer model of a patient with a brain tumor to determine predicted dose rates to the tumor and healthy tissue. The results of this conceptual study indicate an intense, clean beam of epithermal neutrons for NCT clinical trials is attainable in the PBF facility with properly engineered design modifications. 9 refs., 11 figs., 3 tabs

  8. Applications of high power microwaves

    International Nuclear Information System (INIS)

    Benford, J.; Swegle, J.

    1993-01-01

    The authors address a number of applications for HPM technology. There is a strong symbiotic relationship between a developing technology and its emerging applications. New technologies can generate new applications. Conversely, applications can demand development of new technological capability. High-power microwave generating systems come with size and weight penalties and problems associated with the x-radiation and collection of the electron beam. Acceptance of these difficulties requires the identification of a set of applications for which high-power operation is either demanded or results in significant improvements in peRFormance. The authors identify the following applications, and discuss their requirements and operational issues: (1) High-energy RF acceleration; (2) Atmospheric modification (both to produce artificial ionospheric mirrors for radio waves and to save the ozone layer); (3) Radar; (4) Electronic warfare; and (5) Laser pumping. In addition, they discuss several applications requiring high average power than border on HPM, power beaming and plasma heating

  9. Modular High Voltage Power Supply

    Energy Technology Data Exchange (ETDEWEB)

    Newell, Matthew R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-18

    The goal of this project is to develop a modular high voltage power supply that will meet the needs of safeguards applications and provide a modular plug and play supply for use with standard electronic racks.

  10. Beam plug replacement and alignment under high radiation conditions for cold neutron facilities at Hanaro

    International Nuclear Information System (INIS)

    Yeong-Garp, Cho; Jin-Won, Shin; Jung-Hee, Lee; Jeong-Soo, Ryu

    2010-01-01

    Full text : The HANARO, an open-tank-in-pool type research reactor of a 30 MWth power in Korea, has been operating for 15 years since its initial criticality in February 1995. The beam port assigned for the cold neutron at HANARO had been used for an 8-m SANS without neutron guides until it was replaced by a cold neutron guide system in 2008. It was developed a cold neutron guide system for the delivery of cold neutrons from the cold neutron source in the reactor to the neutron scattering instruments in the guide hall. Since the HANARO has been operated from 1995, it was a big challenge to replace the existing plug and shutter with the new facilities under high radiation conditions. When the old plug was removed from the beam port in 2008, the radiation level was 230 mSv/hr at the end of beam port. In addition to that, there were more difficult situations such as the poor as-built dimensions of the beam port, limited work space and time constraint due to other constructions in parallel in the reactor hall. Before the removal of the old plug the level of the radiation was measured coming out through a small hole of the plug to estimate the radiation level during the removal of the old plug and installation of a new plug. Based on the measurement and analysis results, special tools and various shielding facilities were developed for the removal of old in-pile plug and the installation of the new in-pile plug assembly safely. In 2008, the old plug and shutter were successfully replaced by the new plug and shutter as shown in this article with a minimum exposure to the workers. A laser tracker system was also one of the main factors in our successful installation and alignment under high radiation conditions and limited work space. The laser tracker was used to measure and align all the mechanical facilities and the neutron guides with a minimum radiation exposure to workers. The alignment of all the guides and accessories were possible during reactor operation because

  11. Proposed power upgrade of the hot fuel examination facility's neutron radiography reactor

    International Nuclear Information System (INIS)

    Pruett, D.P.; Richards, W.J.; Heidel, C.C.

    1984-01-01

    The Hot Fuel Examination Facility, HFEF, is one of several facilities located at the Argonne Site. HFEF comprises a large hot cell where both non-destructive and destructive examination of highly-irradiated reactor fuels are conducted in support of the LMFBR program. One of the non-destructive examination techniques utilized at HFEF is neutron radiography. When the NRAD facility was designed and constructed, an operating power level of 250 kw was considered to be adequate for obtaining radiographs of the type of specimens envisaged at that time. Since that time, several things have occurred that have tended to increase radiography exposure times to as much as 90 minutes each. In order to decrease exposure times, the reactor power level is to be increased from 250 kW to 1 MW. This increase in power will necessitate several engineering and design changes. The proposed upgrade of the NRAD facility will increase the neutron flux available in the beam tubes appreciably. The increased flux will enable NRAD to continue to meet its operational commitments in a timely manner and to develop state-of-the-art techniques in the future as it has in the past

  12. A study on the sensitivity of self-powered neutron detectors (SPNDs) and a new proposal

    International Nuclear Information System (INIS)

    Lee, Wan No; Cho, Gyu Seong

    1997-01-01

    Self-Powered Neutron Detectors (SPNDs) are currently used to estimate the power generation distribution and fuel burn-up in several nuclear power reactors in Korea. In this paper, Monte Carlo simulation is accomplished to calculate the escape probability of beta particle as a function of their birth position for the typical geometry of rhodium-based SPNDs. Also, a simple numerical method calculates the initial generation rate of beta particles and the change of generation rate due to rhodium burn-up. Using the simulation and the numerical method, the burn-up profile of rhodium density and the neutron sensitivity are calculated as a function of burn-up time in the reactor. The sensitivity of the SPNDs decreases non-linearly due to the high absorption cross-section and the non-uniform burn-up of rhodium in the emitter rod. In addition, for improvement of some properties of rhodium-based SPNDs which are currently used, this paper presents a new material. The method used here can be applied to the analysis of other types of SPNDs and will be useful in the optimum design of new SPNDs for long term usage

  13. Reactor G1: high power experiments

    International Nuclear Information System (INIS)

    Laage, F. de; Teste du Baillet, A.; Veyssiere, A.; Wanner, G.

    1957-01-01

    The experiments carried out in the starting-up programme of the reactor G1 comprised a series of tests at high power, which allowed the following points to be studied: 1- Effect of poisoning by Xenon (absolute value, evolution). 2- Temperature coefficients of the uranium and graphite for a temperature distribution corresponding to heating by fission. 3- Effect of the pressure (due to the coiling system) on the reactivity. 4- Calibration of the security rods as a function of their position in the pile (1). 5- Temperature distribution of the graphite, the sheathing, the uranium and the air leaving the canals, in a pile running normally at high power. 6- Neutron flux distribution in a pile running normally at high power. 7- Determination of the power by nuclear and thermodynamic methods. These experiments have been carried out under two very different pile conditions. From the 1. to the 15. of August 1956, a series of power increases, followed by periods of stabilisation, were induced in a pile containing uranium only, in 457 canals, amounting to about 34 tons of fuel. A knowledge of the efficiency of the control rods in such a pile has made it possible to measure with good accuracy the principal effects at high temperatures, that is, to deal with points 1, 2, 3, 5. Flux charts giving information on the variations of the material Laplacian and extrapolation lengths in the reflector have been drawn up. Finally the thermodynamic power has been measured under good conditions, in spite of some installation difficulties. On September 16, the pile had its final charge of 100 tons. All the canals were loaded, 1,234 with uranium and 53 (i.e. exactly 4 per cent of the total number) with thorium uniformly distributed in a square lattice of 100 cm side. Since technical difficulties prevented the calibration of the control rods, the measurements were limited to the determination of the thermodynamic power and the temperature distributions (points 5 and 7). This report will

  14. Dynamical model of computation of the rhodium self-powered neutron detector current

    International Nuclear Information System (INIS)

    Erben, O.; Slovacek, M.; Zerola, L.

    1992-01-01

    A model is presented for the calculation of the rhodium self-powered neutron detector current in dependence on the neutron flux density during reactor core transients. The total signal consists of a beta emission, prompt, and gamma component and a background signal. The model has been verified by means of experimental data obtained during measurements on the LVR-15 research reactor and at the Dukovany nuclear power plant. (author) 9 figs., 21 refs

  15. A neutron tomography facility at a low power research reactor

    CERN Document Server

    Körner, S; Von Tobel, P; Rauch, H

    2001-01-01

    Neutron radiography (NR) provides a very efficient tool in the field of non-destructive testing as well as for many applications in fundamental research. A neutron beam penetrating a specimen is attenuated by the sample material and detected by a two-dimensional (2D) imaging device. The image contains information about materials and structure inside the sample because neutrons are attenuated according to the basic law of radiation attenuation. Contrary to X-rays, neutrons can be attenuated by some light materials, as for example, hydrogen and boron, but penetrate many heavy materials. Therefore, NR can yield important information not obtainable by more traditional methods. Nevertheless, there are many aspects of structure, both quantitative and qualitative, that are not accessible from 2D transmission images. Hence, there is an interest in three-dimensional neutron imaging. At the 250 kW TRIGA Mark II reactor of the Atominstitut in Austria a neutron tomography facility has been installed. The neutron flux at ...

  16. Neutron dosimetry at nuclear power plants with light water reactors (LWR)

    International Nuclear Information System (INIS)

    Hofmann, B.; Schwarz, W.; Burgkhardt, B.; Piesch, E.

    1989-02-01

    During nuclear start-up of the Muelheim-Kaerlich nuclear power plant in 1986 the neutron radiation fields in the primary and auxiliary component rooms of the containment were investigated using the Single Sphere Albedo Technique and additional measurement techniques. For personnel monitoring albedo neutron dosemeters were used consisting of thermoluminescent detectors and track etch detectors combined with boron converters. Results: (1) The neutron radiation fields reach dose rate values up to 1000 mSv/h at the sleeves of the reactor coolant pipes, in the refuelling pool and the reactor cavity sump. The neutron component varies between 10% in the steam generator rooms up to 92% in the refuelling pool. (2) The mean value of the effective neutron energy at the different locations was found to be about 100 keV. Thermal neutrons contribute with about 10% to the area dose. (3) By direct intercomparisons and different evaluation methods of the Single Sphere Albedo Dosemeter it was shown, that rem-counters used within routine monitoring in the mixed radiation fields of the LWR overestimate the neutron dose rate only insignificantly (+20%) and are therefore usable for practical radiation protection work. (4) The sensitivity of albedo neutron dosemeters allows the detection of neutrons above 10 μSv. The contribution of neutrons to the total personnel dose was 25% in maximum. For the evaluation of albedo detectors a constant calibration factor can be applied. (orig./HP) [de

  17. High Energy Neutron Induced Gamma Production

    International Nuclear Information System (INIS)

    Brown, D.A.; Johnson, M.; Navratil, P.

    2007-01-01

    N Division has an interest in improving the physics and accuracy of the gamma data it provides to its customers. It was asked to look into major gamma producing reactions for 14 MeV incident neutrons for several low-Z materials and determine whether LLNL's processed data files faithfully represent the current state of experimental and theoretical knowledge for these reactions. To address this, we surveyed the evaluations of the requested materials, made recommendations for the next ENDL release and noted isotopes that will require further experimental study. This process uncovered several major problems in our translation and processing of the ENDF formatted evaluations, most of which have been resolved

  18. Unique furnace system for high-energy-neutron experiments

    International Nuclear Information System (INIS)

    Panayotou, N.F.; Green, D.R.; Price, L.S.

    1982-03-01

    The low flux of high energy neutron sources requires optimum utilization of the available neutron field. A furnace system has been developed in support of the US DOE fusion materials program which meets this challenge. Specimens positioned in two temperature zones just 1 mm away from the outside surface of a neutron window in the furnace enclosure can be irradiated simultaneously at two independent, isothermal (+- 1 0 C) temperatures. The temperature difference between these closely spaced isothermal zones is controllable from 0 to 320 0 C and the maximum temperature is 400 0 C. The design of the system also provides a controlled specimen environment, rapid heating and cooling and easy access to heaters and thermocouples. This furnace system is in use at the Rotating Target Neutron Source-II of Lawrence Livermore National Laboratory

  19. High temperature ductility of austenitic alloys exposed to thermal neutrons

    International Nuclear Information System (INIS)

    Watanabe, K.; Kondo, T.; Ogawa, Y.

    1982-01-01

    Loss of high temperature ductility due to thermal neutron irradiation was examined by slow strain rate test in vacuum up to 1000 0 C. The results on two heats of Hastelloy alloy X with different boron contents were analyzed with respect to the influence of the temperatures of irradiation and tensile tests, neutron fluence and the associated helium production due to nuclear transmutation reaction. The loss of ductility was enhanced by increasing either temperature or neutron fluence. Simple extrapolations yielded the estimated threshold fluence and the end-of-life ductility values at 900 and 1000 0 C in case where the materials were used in near-core regions of VHTR. The observed relationship between Ni content and the ductility loss has suggested a potential utilization of Fe-based alloys for seathing of the neutron absorber materials

  20. Transport of accelerator produced high energy neutrons though concrete

    International Nuclear Information System (INIS)

    Prabhakar Rao, G.; Sarkar, P.K.

    1996-01-01

    Development of a computational system for estimating the production and transport of high energy neutrons in particle accelerators is reported. The energy-angle distribution of neutrons from accelerated ions bombarding thick targets is calculated by a hybrid nuclear reaction model code, ALICE-91, modified to suit the purpose. Subsequent transmission of these neutrons through concrete slabs is treated using the anisotropic source-flux iteration technique (ASFIT) in the framework of a coupled neutron-gamma transport. Several parameters of both the codes have been optimized to obtain the transmitted dose through concrete. The calculations are found to be accurate and at the same time faster compared to the detailed Monte Carlo calculations. (author). 8 refs., 2 figs

  1. Self-powered in-core neutron detector assembly with uniform perturbation characteristics

    International Nuclear Information System (INIS)

    Todt, W.H.; Playfoot, K.C.

    1979-01-01

    Disclosed is a self-powered in-core neutron detector assembly in which a plurality of longitudinally extending self-powered detectors have neutron responsive active portions spaced along a longitudinal path. A low neutron absorptive extension extends from the active portions of the spaced active portions of the detectors in symmetrical longitudinal relationship with the spaced active detector portions of each succeeding detector. The detector extension terminates with the detector assembly to provide a uniform perturbation characteristic over the entire assembly length

  2. Self-Powered Neutron Detector Qualification for Absolute On-Line In-Pile Neutron Flux Measurements in BR2

    Science.gov (United States)

    Vermeeren, L.; Wéber, M.

    2003-06-01

    A set of ten Self-Powered Neutron Detectors with Co, Rh and Ag emitters has been irradiated in several channels of the BR2 research reactor at SCK•CEN aiming at a comparison of their performance as thermal neutron flux detectors under various conditions. To allow for a correct interpretation of their signals, all detector sensitivity contributions (prompt and delayed) were calculated using a dedicated Monte Carlo model. The various contributions were also measured separately; the agreement between calculated and experimental data, including data from activation dosimetry, was excellent. Detailed neutron flux profiles were obtained from the SPND data, after correction for the finite detector lengths and for the slow response of delayed SPNDs.

  3. Implantable self-powered detector for on-line determination of neutron flux in patients during NCT treatment.

    Science.gov (United States)

    Miller, M E; Mariani, L E; Gonçalves-Carralves, M L Sztejnberg; Skumanic, M; Thorp, S I

    2004-11-01

    A novel system to determine thermal neutron flux in real time during NCT treatments was developed in the National Atomic Energy Commission of Argentina. The system is based on a special self-powered detector that can be implanted in patients owing to its small size and biocompatibility. High voltage is not required to operate this kind of detectors, which is a considerable advantage in terms of medical uses. By choosing the appropriate materials, it was possible to obtain a prototype with thermal neutron sensitivity providing for an adequate signal level in typical NCT thermal fluxes. It was also possible to minimize gamma response in order to neglect its contribution.

  4. Implantable self-powered detector for on-line determination of neutron flux in patients during NCT treatment

    Energy Technology Data Exchange (ETDEWEB)

    Miller, M.E. E-mail: miller@cae.cnea.gov.ar; Mariani, L.E.; Sztejnberg Goncalves-Carralves, M.L.; Skumanic, M.; Thorp, S.I

    2004-11-01

    A novel system to determine thermal neutron flux in real time during NCT treatments was developed in the National Atomic Energy Commission of Argentina. The system is based on a special self-powered detector that can be implanted in patients owing to its small size and biocompatibility. High voltage is not required to operate this kind of detectors, which is a considerable advantage in terms of medical uses. By choosing the appropriate materials, it was possible to obtain a prototype with thermal neutron sensitivity providing for an adequate signal level in typical NCT thermal fluxes. It was also possible to minimize gamma response in order to neglect its contribution.

  5. Burnup Estimation of Rhodium Self-Powered Neutron Detector Emitter in VVER Reactor Core Using Monte Carlo Simulations

    OpenAIRE

    Khrutchinsky, А. А.; Kuten, S. A.; Babichev, L. F.

    2011-01-01

    Estimation of burn-up in a rhodium-103 emitter of self-powered neutron detector in VVER-1000 reactor core has been performed using Monte Carlo simulations within approximation of a constant neutron flux.

  6. Neutronic calculations in support of the design of the ITER High Resolution Neutron Spectrometer

    International Nuclear Information System (INIS)

    Moro, F.; Esposito, B.; Marocco, D.; Villari, R.; Petrizzi, L.; Sunden, E. Andersson; Conroy, S.; Ericsson, G.; Johnson, M. Gatu; Dapena, M.

    2011-01-01

    This paper presents the results of neutronic calculations performed to address important issues related to the optimization of the ITER HRNS (High resolution Neutron Spectrometer) design, in particular concerning the definition of the collimator and the choice of the detector system. The calculations have been carried out using the MCNP5 Monte Carlo code in a full 3-D geometry. The HRNS collimation system has been included in the latest MCNP ITER 40 o model (Alite-4). The ITER scenario 2 reference DT plasma fusion neutron source peaked at 14.1 MeV with Gaussian energy distribution has been used. Neutron fluxes and energy spectra (>1 MeV) have been evaluated at different positions along the HRNS collimator and at the detector location. The noise-to-signal ratio (i.e. the ratio of collided to uncollided neutrons), the breakdown of the collided spectrum into its components, the dependency on the first wall aperture and the gamma-ray spectra at the detector position have also been analyzed. The impact of the results on the design of the HRNS diagnostic system is discussed.

  7. High power klystrons for efficient reliable high power amplifiers

    Science.gov (United States)

    Levin, M.

    1980-11-01

    This report covers the design of reliable high efficiency, high power klystrons which may be used in both existing and proposed troposcatter radio systems. High Power (10 kW) klystron designs were generated in C-band (4.4 GHz to 5.0 GHz), S-band (2.5 GHz to 2.7 GHz), and L-band or UHF frequencies (755 MHz to 985 MHz). The tubes were designed for power supply compatibility and use with a vapor/liquid phase heat exchanger. Four (4) S-band tubes were developed in the course of this program along with two (2) matching focusing solenoids and two (2) heat exchangers. These tubes use five (5) tuners with counters which are attached to the focusing solenoids. A reliability mathematical model of the tube and heat exchanger system was also generated.

  8. Design studies for a high-resolution, transportable neutron radiography/radioscopy system

    International Nuclear Information System (INIS)

    Gillespie, G.H.; Micklich, B.J.; McMichael, G.E.

    1996-01-01

    A preliminary design has been developed for a high-resolution, transportable neutron radiology system (TNRS) concept. The primary system requirement is taken to be a thermal neutron flux of 10[sup 6] n/(cm[sup 2]-sec) with a L/D ratio of 100. The approach is to use an accelerator-driven neutron source, with a radiofrequency quadrupole (RFQ) as the primary accelerator component. Initial concepts for all of the major components of the system have been developed,and selected key parts have been examined further. An overview of the system design is presented, together with brief summaries of the concepts for the ion source, low energy beam transport (LEBT), RFQ, high energy beam transport (HEBT), target, moderator, collimator, image collection, power, cooling, vacuum, structure, robotics, control system, data analysis, transport vehicle, and site support. The use of trade studies for optimizing the TNRS concept are also described

  9. Hexagonal boron nitride neutron detectors with high detection efficiencies

    Science.gov (United States)

    Maity, A.; Grenadier, S. J.; Li, J.; Lin, J. Y.; Jiang, H. X.

    2018-01-01

    Neutron detectors fabricated from 10B enriched hexagonal boron nitride (h-10BN or h-BN) epilayers have demonstrated the highest thermal neutron detection efficiency among solid-state neutron detectors to date at about 53%. In this work, photoconductive-like vertical detectors with a detection area of 1 × 1 mm2 were fabricated from 50 μm thick free-standing h-BN epilayers using Ni/Au and Ti/Al bilayers as ohmic contacts. Leakage currents, mobility-lifetime (μτ) products under UV photoexcitation, and neutron detection efficiencies have been measured for a total of 16 different device configurations. The results have unambiguously identified that detectors incorporating the Ni/Au bilayer on both surfaces as ohmic contacts and using the negatively biased top surface for neutron irradiation are the most desired device configurations. It was noted that high growth temperatures of h-10BN epilayers on sapphire substrates tend to yield a higher concentration of oxygen impurities near the bottom surface, leading to a better device performance by the chosen top surface for irradiation than by the bottom. Preferential scattering of oxygen donors tends to reduce the mobility of holes more than that of electrons, making the biasing scheme with the ability of rapidly extracting holes at the irradiated surface while leaving the electrons to travel a large average distance inside the detector at a preferred choice. When measured against a calibrated 6LiF filled micro-structured semiconductor neutron detector, it was shown that the optimized configuration has pushed the detection efficiency of h-BN neutron detectors to 58%. These detailed studies also provided a better understanding of growth-mediated impurities in h-BN epilayers and their effects on the charge collection and neutron detection efficiencies.

  10. Neutron activation analysis: a powerful tool in provenance investigations

    International Nuclear Information System (INIS)

    Meloni, Sandro; Oddone, Massimo

    2002-01-01

    It is well known that neutron activation analysis (NAA), both instrumental and destructive, allows the simultaneous determination of a number of elements, mostly trace elements, with high levels of precision and accuracy. These peculiar properties of NAA are very useful when applied to provenance studies, i.e. to the identification of the origin of raw materials with which artifacts had been manufactured in ancient times. Data reduction by statistical procedures, especially multivariate analysis techniques, provides a statistical 'fingerprint' of investigated materials, both raw materials and archaeological artifacts, that, upon comparison, allows the identification of the provenance of prime matters used for artifact manufacturing. Thus information on quarries and flows exploitation in the antiquity, on technological raw materials processing, on trade routes and about the circulation of fakes, can be obtained. In the present paper two case studies are reported. The first one deals with the identification of the provenance of clay used to make ceramic materials, mostly bricks and tiles, recovered from the excavation of a Roman 'villa' in Lomello (Roman name Laumellum) and of Roman settlings in Casteggio (Roman name Clastidium). Both sites are located in the Province of Pavia in areas called Lomellina and Oltrepo respectively. The second one investigates the origin of the white marble used to build medieval arks, Carolingian age, located in the church of San Felice, now property of the University of Pavia. Experimental set-up, analytical results and data reduction procedures are presented and discussed. (author)

  11. High speed motion neutron radiography of two-phase flow

    International Nuclear Information System (INIS)

    Robinson, A.H.; Wang, S.L.

    1983-01-01

    Current research in the area of two-phase flow utilizes a wide variety of sensing devices, but some limitations exist on the information which can be obtained. Neutron radiography is a feasible alternative to ''see'' the two-phase flow. A system to perform neutron radiographic analysis of dynamic events which occur on the order of several milliseconds has been developed at Oregon State University. Two different methods have been used to radiograph the simulated two-phase flow. These are pulsed, or ''flash'' radiography, and high speed movie neutron radiography. The pulsed method serves as a ''snap-shot'' with an exposure time ranging from 10 to 20 milliseconds. In high speed movie radiography, a scintillator is used to convert neutrons into light which is enhanced by an optical intensifier and then photographed by a high speed camera. Both types of radiography utilize the pulsing capability of the OSU TRIGA reactor. The principle difficulty with this type of neutron radiography is the fogging of the image due to the large amount of scattering in the water. This difficulty can be overcome by using thin regions for the two-phase flow or using heavy water instead of light water. The results obtained in this paper demonstrate the feasibility of using neutron radiography to obtain data in two-phase flow situations. Both movies and flash radiographs have been obtained of air bubbles in water and boiling from a heater element. The neutron radiographs of the boiling element show both nucleate boiling and film boiling. (Auth.)

  12. Compendium of Neutron Beam Facilities for High Precision Nuclear Data Measurements

    International Nuclear Information System (INIS)

    2014-07-01

    The recent advances in the development of nuclear science and technology, demonstrating the globally growing economy, require highly accurate, powerful simulations and precise analysis of the experimental results. Confidence in these results is still determined by the accuracy of the atomic and nuclear input data. For studying material response, neutron beams produced from accelerators and research reactors in broad energy spectra are reliable and indispensable tools to obtain high accuracy experimental results for neutron induced reactions. The IAEA supports the accomplishment of high precision nuclear data using nuclear facilities in particular, based on particle accelerators and research reactors around the world. Such data are essential for numerous applications in various industries and research institutions, including the safety and economical operation of nuclear power plants, future fusion reactors, nuclear medicine and non-destructive testing technologies. The IAEA organized and coordinated the technical meeting Use of Neutron Beams for High Precision Nuclear Data Measurements, in Budapest, Hungary, 10–14 December 2012. The meeting was attended by participants from 25 Member States and three international organizations — the European Organization for Nuclear Research (CERN), the Joint Research Centre (JRC) and the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (OECD/NEA). The objectives of the meeting were to provide a forum to exchange existing know-how and to share the practical experiences of neutron beam facilities and associated instrumentation, with regard to the measurement of high precision nuclear data using both accelerators and research reactors. Furthermore, the present status and future developments of worldwide accelerator and research reactor based neutron beam facilities were discussed. This publication is a summary of the technical meeting and additional materials supplied by the international

  13. Compendium of Neutron Beam Facilities for High Precision Nuclear Data Measurements. Annex: Individual Reports

    International Nuclear Information System (INIS)

    2014-07-01

    The recent advances in the development of nuclear science and technology, demonstrating the globally growing economy, require highly accurate, powerful simulations and precise analysis of the experimental results. Confidence in these results is still determined by the accuracy of the atomic and nuclear input data. For studying material response, neutron beams produced from accelerators and research reactors in broad energy spectra are reliable and indispensable tools to obtain high accuracy experimental results for neutron induced reactions. The IAEA supports the accomplishment of high precision nuclear data using nuclear facilities in particular, based on particle accelerators and research reactors around the world. Such data are essential for numerous applications in various industries and research institutions, including the safety and economical operation of nuclear power plants, future fusion reactors, nuclear medicine and non-destructive testing technologies. The IAEA organized and coordinated the technical meeting Use of Neutron Beams for High Precision Nuclear Data Measurements, in Budapest, Hungary, 10–14 December 2012. The meeting was attended by participants from 25 Member States and three international organizations — the European Organization for Nuclear Research (CERN), the Joint Research Centre (JRC) and the Organisation for Economic Co-operation and Development (OECD) Nuclear Energy Agency (OECD/NEA). The objectives of the meeting were to provide a forum to exchange existing know-how and to share the practical experiences of neutron beam facilities and associated instrumentation, with regard to the measurement of high precision nuclear data using both accelerators and research reactors. Furthermore, the present status and future developments of worldwide accelerator and research reactor based neutron beam facilities were discussed. This publication is a summary of the technical meeting and additional materials supplied by the international

  14. High temperature neutron diffraction study of LaPO4

    International Nuclear Information System (INIS)

    Mishra, S.K.; Mittal, R.; Ningthoujam, R.S.; Vatsa, R.K.; Hansen, T.

    2016-01-01

    We report high temperature powder neutron diffractions study in LaPO 4 using high-flux D20 neutron diffractometer in the Institut Laue-Langevin, France. The measurements were carried out in high resolution mode (incident neutron wavelength 1.36 A) at various temperature upto 900°C. CarefuI inspection of temperature dependence of diffraction data showed appearance and disappearance of certain Bragg's reflections above 1273 K. It is a signature of structural phase transition. Rietveld refinement of the powder diffraction data revealed that diffraction patterns at and above 800°C could be indexed using the monoclinic structure with P21/n space group. Detail analysis for identify the water molecules is under investigation. (author)

  15. A study on the sensitivity depletion laws for rhodium self-powered neutron detectors

    International Nuclear Information System (INIS)

    Kim, Gil Gon

    1999-02-01

    The rhodium self-powered neutron detectors (SPND) in a reactor core provide the operator with the on-line 3-dimensional nuclear power distribution. The signal produced by rhodium SPND is interpreted into the local neutron flux by using a sensitivity depletion law and the local neutron flux is interpreted into the local power by using a power conversion factor. This work on the sensitivity depletion laws for rhodium self-powered neutron detectors (SPND) is performed to improve the uncertainty of the sensitivity depletion law used in ABB-CE reactors employing a rhodium SPND and to develop a calculational tool for providing the sensitivity depletion laws to interpret the signal of the newly designed rhodium SPND into the local neutron flux. The calculational tools for a time dependent neutron flux distribution in the rhodium emitter during depletion and for a time dependent beta escape probability that a beta generated in the emitter is escaped into the collector were developed. Due to the cost, the exposure to the radiation, and the longer fuel cycle, there is a strong incentive that the loading density of an in-core instrumentation is reduced and the lifetime of the detector is lengthened. These objectives can be achieved by reducing the uncertainty which is amplified as it depletes. The calculational tools above provide the sensitivity depletion law and show the reduction of the uncertainty to about 1 % in interpreting the signal into the local neutron flux compared to the method employed by ABB-CE. The reduction in the uncertainty of 1 % in interpreting the signal into the local neutron flux is equivalent to the reduction in the uncertainty of 1 % or more in interpreting the signal into the local power and to the extension of the lifetime of rhodium SPND to about 10 % as reported by ABB-CE

  16. Major projects for the use of high power linacs

    International Nuclear Information System (INIS)

    Prome, M.

    1996-01-01

    A review of the major projects for high power linacs is given. The field covers the projects aiming at the transmutation of nuclear waste or the production of tritium, as well as the production of neutrons for hybrid reactors or basic research with neutron sources. The technologies which arc common to all the projects are discussed. Comments are made on the technical difficulties encountered by all the projects, and the special problems of the pulsed linacs are mentioned. Elements for a comparison of normal conducting linacs versus superconducting ones are given. Finally the technical developments being made in various laboratories are reviewed. (author)

  17. Radiation damage in molybdenum and tungsten in high neutron fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Veljkovic, S; Milasin, N [Institute of Nuclear Sciences Boris Kidric, Department of Reactor Materials, Vinca, Beograd (Serbia and Montenegro)

    1964-04-15

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  18. Radiation damage in molybdenum and tungsten in high neutron fluxes

    International Nuclear Information System (INIS)

    Veljkovic, S.; Milasin, N.

    1964-01-01

    The effects of radiation on molybdenum and tungsten in high neutron fluxes are presented. The changes induced, particularly defects with a high migration activation energy, are analyzed. The correlation of these changes with the basic concepts of radiation damage in solids is considered. An attempt is made to relate the defects studied with the changes in macroscopic properties (author)

  19. Research activities on dosimetry for high energy neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Yasuhiro [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The external dosimetry research group of JAERI has been calculating dose conversion coefficients for high-energy radiations using particle transport simulation codes. The group has also been developing radiation dose measurement techniques for high-energy neutrons in collaboration with some university groups. (author)

  20. Methods and applications in high flux neutron imaging

    International Nuclear Information System (INIS)

    Ballhausen, H.

    2007-01-01

    This treatise develops new methods for high flux neutron radiography and high flux neutron tomography and describes some of their applications in actual experiments. Instead of single images, time series can be acquired with short exposure times due to the available high intensity. To best use the increased amount of information, new estimators are proposed, which extract accurate results from the recorded ensembles, even if the individual piece of data is very noisy and in addition severely affected by systematic errors such as an influence of gamma background radiation. The spatial resolution of neutron radiographies, usually limited by beam divergence and inherent resolution of the scintillator, can be significantly increased by scanning the sample with a pinhole-micro-collimator. This technique circumvents any limitations in present detector design and, due to the available high intensity, could be successfully tested. Imaging with scattered neutrons as opposed to conventional total attenuation based imaging determines separately the absorption and scattering cross sections within the sample. For the first time even coherent angle dependent scattering could be visualized space-resolved. New applications of high flux neutron imaging are presented, such as materials engineering experiments on innovative metal joints, time-resolved tomography on multilayer stacks of fuel cells under operation, and others. A new implementation of an algorithm for the algebraic reconstruction of tomography data executes even in case of missing information, such as limited angle tomography, and returns quantitative reconstructions. The setup of the world-leading high flux radiography and tomography facility at the Institut Laue-Langevin is presented. A comprehensive appendix covers the physical and technical foundations of neutron imaging. (orig.)

  1. Pulsed high-power beams

    International Nuclear Information System (INIS)

    Reginato, L.L.; Birx, D.L.

    1988-01-01

    The marriage of induction linac technology with nonlinear magnetic modulators has produced some unique capabilities. It is now possible to produce short-pulse electron beams with average currents measured in amperes, at gradients approaching 1-MeV/m, and with power efficiencies exceeding 50%. This paper reports on a 70-MeV, 3-kA induction accelerator (ETA II) constructed at the Lawrence Livermore National Laboratory that incorporates the pulse technology concepts that have evolved over the past several years. The ETA II is a linear induction accelerator and provides a test facility for demonstration of the high-average-power components and high-brightness sources used in such accelerators. The pulse drive of the accelerator is based on state-of-the-art magnetic pulse compressors with very high peak-power capability, repetition rates exceeding 1 kHz, and excellent reliability

  2. High temperature superconductors for fusion magnets -influence of neutron irradiation

    International Nuclear Information System (INIS)

    Chudy, M.; Eisterer, M.; Weber, H. W.

    2010-01-01

    In this work authors present the results of study of influence of neutron irradiation of high temperature superconductors for fusion magnets. High temperature superconductors (type of YBCO (Yttrium-Barium-Copper-Oxygen)) are strong candidates to be applied in the next step of fusion devices. Defects induced by fast neutrons are effective pinning centres, which can significantly improve critical current densities and reduce J c anisotropy. Due to induced lattice disorder, T c is reduced. Requirements for ITER (DEMO) are partially achieved at 64 K.

  3. High-pressure cell for simultaneous dielectric and neutron spectroscopy

    DEFF Research Database (Denmark)

    Sanz, Alejandro; Hansen, Henriette Wase; Jakobsen, Bo

    2018-01-01

    In this article, we report on the design, manufacture, and testing of a high-pressure cell for simultaneous dielectric and neutron spectroscopy. This cell is a unique tool for studying dynamics on different time scales, from kilo- to picoseconds, covering universal features such as the α relaxation......, a cylindrical capacitor is positioned within the bore of the high-pressure container. The capacitor consists of two concentric electrodes separated by insulating spacers. The performance of this setup has been successfully verified by collecting simultaneous dielectric and neutron spectroscopy data...

  4. Fusion materials high energy-neutron studies. A status report

    International Nuclear Information System (INIS)

    Doran, D.G.; Guinan, M.W.

    1980-01-01

    The objectives of this paper are (1) to provide background information on the US Magnetic Fusion Reactor Materials Program, (2) to provide a framework for evaluating nuclear data needs associated with high energy neutron irradiations, and (3) to show the current status of relevant high energy neutron studies. Since the last symposium, the greatest strides in cross section development have been taken in those areas providing FMIT design data, e.g., source description, shielding, and activation. In addition, many dosimetry cross sections have been tentatively extrapolated to 40 MeV and integral testing begun. Extensive total helium measurements have been made in a variety of neutron spectra. Additional calculations are needed to assist in determining energy dependent cross sections

  5. Response function measurement of plastic scintillator for high energy neutrons

    International Nuclear Information System (INIS)

    Sanami, Toshiya; Ban, Syuichi; Takahashi, Kazutoshi; Takada, Masashi

    2003-01-01

    The response function and detection efficiency of 2''φ x 2''L plastic (PilotU) and NE213 liquid (2''NE213) scintillators, which were used for the measurement of secondary neutrons from high energy electron induced reactions, were measured at Heavy Ion Medical Accelerator in Chiba (HIMAC). High energy neutrons were produced via 400 MeV/n C beam bombardment on a thick graphite target. The detectors were placed at 15 deg with respect to C beam axis, 5 m away from the target. As standard, a 5''φ x 5''L NE213 liquid scintillator (5''NE213) was also placed at same position. Neutron energy was determined by the time-of-flight method with the beam pickup scintillator in front of the target. In front of the detectors, veto scintillators were placed to remove charged particle events. All detector signals were corrected with list mode event by event. We deduce neutron spectrum for each detectors. The efficiency curves for pilotU and 2''NE213 were determined on the bases of 5 N E213 neutron spectrum and its efficiency calculated by CECIL code. (author)

  6. Neutron scattering at the high-flux isotope reactor

    International Nuclear Information System (INIS)

    Cable, J.W. Chakoumakos, B.C.; Dai, P.

    1995-01-01

    The title facilities offer the brightest source of neutrons in the national user program. Neutron scattering experiments probe the structure and dynamics of materials in unique and complementary ways as compared to x-ray scattering methods and provide fundamental data on materials of interest to solid state physicists, chemists, biologists, polymer scientists, colloid scientists, mineralogists, and metallurgists. Instrumentation at the High- Flux Isotope Reactor includes triple-axis spectrometers for inelastic scattering experiments, a single-crystal four diffractometer for crystal structural studies, a high-resolution powder diffractometer for nuclear and magnetic structure studies, a wide-angle diffractometer for dynamic powder studies and measurements of diffuse scattering in crystals, a small-angle neutron scattering (SANS) instrument used primarily to study structure-function relationships in polymers and biological macromolecules, a neutron reflectometer for studies of surface and thin-film structures, and residual stress instrumentation for determining macro- and micro-stresses in structural metals and ceramics. Research highlights of these areas will illustrate the current state of neutron science to study the physical properties of materials

  7. High power laser exciter accelerators

    International Nuclear Information System (INIS)

    Martin, T.H.

    1975-01-01

    Recent developments in untriggered oil and water switching now permit the construction of compact, high energy density pulsed power sources for laser excitation. These accelerators, developed principally for electron beam fusion studies, appear adaptable to laser excitation and will provide electron beams of 10 13 to 10 14 W in the next several years. The accelerators proposed for e-beam fusion essentially concentrate the available power from the outside edge of a disk into the central region where the electron beam is formed. One of the main problem areas, that of power flow at the vacuum diode insulator, is greatly alleviated by the multiplicity of electron beams that are allowable for laser excitation. A proposal is made whereby the disk-shaped pulsed power sections are stacked vertically to form a series of radially flowing electron beams to excite the laser gas volume. (auth)

  8. Initial absolute calibration factors for some neutron sensitive self-powered detectors

    International Nuclear Information System (INIS)

    Kroon, J.

    1975-01-01

    Self-powered flux detectors have found extensive use as monitoring devices in PWR (Pressurized Water Reactor) cores and CANDU (Canada Deuterium Uranium) type power reactors. The detectors measure fuel power distributions and indicate trip parameters for reactor control and safety requirements. Both applications demand accurate absolute initial calibration factors. Experimental results obtained in calibrating some neutron sensitive self-powered detectors is presented. (author)

  9. Neutron dosimetry in EDF experimental surveillance programme for VVER-440 nuclear power plants

    International Nuclear Information System (INIS)

    Brumovsky, M.; Erben, O.; Novosad, P.; Zerola, L.; Hogel, J.; Trollat, C.

    2001-01-01

    Fourteen chains containing experimental surveillance material specimens of the VVER 440/213 nuclear power reactor pressure vessels were irradiated in the surveillance channels of the Nuclear Power Plant Dukovany in the Czech Republic. The irradiation periods were one, two or three cycles. The chains contained different number and types of containers, the omitted ones were replaced by chain elements. All of the containers were instrumented with wire neutron fluence detectors, some of the containers in the chain had spectrometric sets of neutron fluence monitors. For the absolute fluence values evaluation it was taken into account time history of the reactor power and local changes of the neutron flux along the reactor core height, correction factors due to the orientation of monitors with respect to the reactor core centre. Unfolding programs SAND-II or BASA-CF were used. The relative axial fluence distribution was obtained from the O-wire measurements. Neutron fluence values above 0.5 MeV energy and above 1.0 MeV energy in the container axis on the axial positions of the sample centres and fluence values in the geometric centre of the samples was calculated making use the exponential attenuation model of the incident neutron beam. Received fast neutron fluence values can be used as reference values to all VVER-440 type 213 nuclear power plant reactors. (author)

  10. Fusion neutronics plan in the development of fusion reactor. With the aim of realizing electric power

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hiroo; Morimoto, Yuichi; Ochiai, Kentarou; Sugimoto, Masayoshi; Nishitani, Takeo; Takeuchi, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2000-10-01

    On June 1992, Atomic Energy Commission in Japan has settled Third Phase Program of Fusion Research and Development to achieve self-ignition condition, to realize long pulse burning plasma and to establish basis of fusion engineering for demonstration reactor. This report describes research plan of Fusion Neutron Laboratory in JAERI toward a development of fusion reactor with an aim of realizing electric power. The fusion neutron laboratory has a fusion neutronics facility (FNS), intense fusion neutron source. The plan includes research items in the FNS; characteristics of shielding and breeding materials, nuclear characteristics of materials, fundamental irradiation process of insulator, diagnostics materials and structural materials, and development of in-vessel diagnostic technology. Upgrade of the FNS is also described. Also, the International Fusion Material Irradiation Facility (IFMIF) for intense neutron source to develop fusion materials is described. (author)

  11. Design, construction and testing of a self-powered neutron detector

    International Nuclear Information System (INIS)

    Correa, R.F.

    1987-01-01

    The design, construction and testing of a self-powered neutron detector (SPN) and associated electronics are described. Several tests were performed giving information about dielectrical properties of detector and cable, gamma spectra induced in the detector through reactor irradiation, detector response as a function of neutron flux, current stability and reproductibility with the neutron flux. The gamma and neutron sensitivities were also evaluated, by means of thermoluminescent dosimeters and gold foils as references. The test results are presented and show that the detector response is reliable. The gamma and neutron sensitivities are in agreement with those found in the available literature. Nevertheless, a ceramic insulated cable should be employed for permanent use in a reactor. The tests were performed in a 100 KW TRIGA Mark I reactor at the Centro de Desenvolvimento da Tecnologia Nuclear of NUCLEBRAS, in Belo Horizonte, Brazil. (author) [pt

  12. Design constrution and testing of a self-powered neutron detector

    International Nuclear Information System (INIS)

    Correa, R.F.

    1987-01-01

    The design, contruction and testing of a self-powered neutron detector (SPN) and associated electronics are described. Several tests were performed giving information about dielectrical properties od detector and cable, gamma spectra induced in the detector through reactor irradiation, detector response as a function of neutron flux, current stability and reproductibility with the neutron flux. The gamma and neutron sensitivities were also evaluated, by means of thermoluminescent dosimeters and gold foils as references. The test results are presented and show that the detector response is reliable. The gamma and neutron sensitivities are in agreement with those found in the available literature. Neverthe less, a ceramic insulated cable should be employed for permanent use in a reactor. The tests were perfomance in a 100 kW TRIGA Mark I reactor at the Centro de Desenvolvimento da Tecnologia Nuclear of NUCLEBRAS,in Belo Horizonte, Brazil. (Author) [pt

  13. Neutron resonance transmission spectroscopy with high spatial and energy resolution at the J-PARC pulsed neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Shinohara, T.; Kai, T.; Ooi, M. [Japan Atomic Energy Agency, 2–4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); Kamiyama, T.; Kiyanagi, Y.; Shiota, Y. [Hokkaido University, Kita 13 Nishi 8 Kita-ku, Sapporo-shi, Hokkaido 060-8628 (Japan); McPhate, J.B.; Vallerga, J.V.; Siegmund, O.H.W. [University of California at Berkeley, 7 Gauss Way, Berkeley, CA 94720 (United States); Feller, W.B. [NOVA Scientific, Inc., 10 Picker Rd., Sturbridge, MA 01566 (United States)

    2014-05-11

    The sharp variation of neutron attenuation at certain energies specific to particular nuclides (the lower range being from ∼1 eV up to ∼1 keV), can be exploited for the remote mapping of element and/or isotope distributions, as well as temperature probing, within relatively thick samples. Intense pulsed neutron beam-lines at spallation sources combined with a high spatial, high-timing resolution neutron counting detector, provide a unique opportunity to measure neutron transmission spectra through the time-of-flight technique. We present the results of experiments where spatially resolved neutron resonances were measured, at energies up to 50 keV. These experiments were performed with the intense flux low background NOBORU neutron beamline at the J-PARC neutron source and the high timing resolution (∼20 ns at epithermal neutron energies) and spatial resolution (∼55 µm) neutron counting detector using microchannel plates coupled to a Timepix electronic readout. Simultaneous element-specific imaging was carried out for several materials, at a spatial resolution of ∼150 µm. The high timing resolution of our detector combined with the low background beamline, also enabled characterization of the neutron pulse itself – specifically its pulse width, which varies with neutron energy. The results of our measurements are in good agreement with the predicted results for the double pulse structure of the J-PARC facility, which provides two 100 ns-wide proton pulses separated by 600 ns, broadened by the neutron energy moderation process. Thermal neutron radiography can be conducted simultaneously with resonance transmission spectroscopy, and can reveal the internal structure of the samples. The transmission spectra measured in our experiments demonstrate the feasibility of mapping elemental distributions using this non-destructive technique, for those elements (and in certain cases, specific isotopes), which have resonance energies below a few keV, and with lower

  14. High power fast ramping power supplies

    Energy Technology Data Exchange (ETDEWEB)

    Marneris,I.; Bajon, E.; Bonati, R.; Sandberg, J.; Roser, T.; Tsoupas, N.

    2009-05-04

    Hundred megawatt level fast ramping power converters to drive proton and heavy ion machines are under research and development at accelerator facilities in the world. This is a leading edge technology. There are several topologies to achieve this power level. Their advantages and related issues will be discussed.

  15. Neutronics shielding analysis of the last mirror-beam duct system for a laser fusion power reactor

    International Nuclear Information System (INIS)

    Ragheb, M.M.H.; Klein, A.C.

    1981-01-01

    A Monte Carlo three-dimensional neutronics analysis for the last mirror-beam duct system for the SOLASE conceptual laser-driven fusion power reactor design is presented. Detailed geometric configurations including the reactor cavity, the two last mirrors, and the three-section two-right-angle bends duct are modeled. Measurements are given of the dimensions and compositions of the reactor components, and of neutron scalar fluxes, spatial dependencies and neutron volumetric heating rates for the cases of aluminum or Boral as laser beam duct liners, and ordinary concrete or lead mortar as shield material. A three-dimensional modeling of laser-driven reactor penetrations is employed. The particle leakage is found to be excessively high for the configuration of the conceptual design considered and the advantages and disadvantages of various solutions, such as the use of Boral as a duct liner and the use of lead mortar instead of ordinary concrete as a shield material, are considered

  16. Electron scattering from high-momentum neutrons in deuterium

    International Nuclear Information System (INIS)

    Klimenko, A.V.; Kuhn, S.E.; Bueltmann, S.; Careccia, S.L.; Dharmawardane, K.V.; Dodge, G.E.; Guler, N.; Hyde-Wright, C.E.; Klein, A.; Tkachenko, S.; Weinstein, L.B.; Zhang, J.; Butuceanu, C.; Griffioen, K.A.; Baillie, N.; Fersch, R.G.; Funsten, H.; Egiyan, K.S.; Asryan, G.; Dashyan, N.B.

    2006-01-01

    We report results from an experiment measuring the semiinclusive reaction 2 H(e,e ' p s ) in which the proton p s is moving at a large angle relative to the momentum transfer. If we assume that the proton was a spectator to the reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred. This method, known as spectator tagging, can be used to study electron scattering from high-momentum (off-shell) neutrons in deuterium. The data were taken with a 5.765 GeV electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CEBAF large acceptance spectrometer. A reduced cross section was extracted for different values of final state missing mass W*, backward proton momentum p → s , and momentum transfer Q 2 . The data are compared to a simple plane wave impulse approximation (PWIA) spectator model. A strong enhancement in the data observed at transverse kinematics is not reproduced by the PWIA model. This enhancement can likely be associated with the contribution of final state interactions (FSI) that were not incorporated into the model. Within the framework of the simple spectator model, a 'bound neutron structure function' F 2n eff was extracted as a function of W* and the scaling variable x* at extreme backward kinematics, where the effects of FSI appear to be smaller. For p s >0.4 GeV/c, where the neutron is far off-shell, the model overestimates the value of F 2n eff in the region of x* between 0.25 and 0.6. A dependence of the bound neutron structure function on the neutron's 'off-shell-ness' is one possible effect that can cause the observed deviation

  17. Use of self powered neutron detectors in the IEA-R1 reactor

    International Nuclear Information System (INIS)

    Galo Rocha, F. del.

    1989-01-01

    A survey of self-powered neutron detectors, SPND, which are used as part of the in-core instrumentation of nuclear reactors is presented. Measurements with Co and Er SPND's were made in the IEA-R1 reactor for determining the neutron flux distribution and the integral reactor power. Due to the size of the available detectors, the neutron flux distribution could not be obtained with accuracy. The results obtained in the reactor power measurements demonstrate that the SPND have the linearity and the quick response necessary for a reactor power channel. This work also presents a proposed design of a SPND using Pt as wire emissor. This proposed design is based in the experience gained in building two prototypes. The greatest difficulties encountered include materials and technology to perform the delicate weldings. (author)

  18. High-power, high-efficiency FELs

    International Nuclear Information System (INIS)

    Sessler, A.M.

    1989-04-01

    High power, high efficiency FELs require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e. optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (i.e sidebands). 18 refs., 7 figs., 3 tabs

  19. Investigation of the response of improved self-powered neutron detectors

    International Nuclear Information System (INIS)

    Erk, S.

    1982-01-01

    The self-powered neutron detectors have been successfully employed for the most important parameters both for neutron flux and flux fluence determination. Their preference for such measurements due to their simplicity, convenience in use, rigidity, voluminal smallness and low price. However, self-powered neutron detectors depend on the type used, can only follow the neutron flux changes with a certain delay when they are compared to fission chambers which are thought to be the best detectors. In this thesis, a system has been proposed and considered carefully in order to speed up the response time, in another word, to correct the detector response to a level very near to fission chamber performance, a circuitry has been realized in the frame of principles so forth and applied to the experiments carried out in the TR-1 Reactor. Their positive results are presented. (author)

  20. Design and fabrication of self-powered in-core neutron flux monitor assembly

    International Nuclear Information System (INIS)

    Chung, M.K.; Cho, S.W.; Kang, H.D.; Cho, K.K.; Cho, B.S.; Kang, S.S.

    1980-01-01

    This is the final report on the prototypical fabrication of an in-core neutron flux monitor detector assembly for a specific power reactor conducted by KAERI from July 1, 1978 to December 31, 1979. It is well known that power reactors require a large number of in-core neutron flux detector for reactor regulation and the structures of detector assemblies are different from reactor to reactor. Therefore, from the nature of this project, it should be noted here that the target model of the prototypical farbrication of an in-core neutron flux monitor detector assembly is a VFD-2 System for Wolsung CANDU. It is concluded that fabrication of in-core neutron flux monitor detector assembly for CANDU reactor is technically feasible and will bring economical benefit as much as 50 % of the unit price if they are fabricated in Korea by using partially materials which are available from local market. (author)

  1. Dosimetry of the Embalse nuclear power plant neutron/gamma mixed fields

    International Nuclear Information System (INIS)

    Salas, C.A.

    1990-01-01

    The aim of this work is to describe the method used at the Embalse nuclear power plant for carrying out personal dosimetry of the agents affected to the tasks on the Embalse nuclear power plant neutron-gamma mixed fields. (Author) [es

  2. High voltage power network construction

    CERN Document Server

    Harker, Keith

    2018-01-01

    This book examines the key requirements, considerations, complexities and constraints relevant to the task of high voltage power network construction, from design, finance, contracts and project management to installation and commissioning, with the aim of providing an overview of the holistic end to end construction task in a single volume.

  3. The determination of self-powered neutron detector sensitivity on thermal and epithermal neutron flux densities

    International Nuclear Information System (INIS)

    Erben, O.

    1980-01-01

    The coefficients of thermal and epithermal neutron flux density depression and self-shielding for the SPN detectors with vanadium, rhodium, silver and cobalt emitters are presented, (for cobalt SPN detectors the functions describing the absorbtion of neutrons along the emitter cross-section are also shown). Using these coefficients and previously published beta particle escape efficiencies, sensitivities are determined for the principal types of detectors produced by Les Cables de Lyon and SODERN companies. The experiments and their results verifying the validity of the theoretical work are described. (author)

  4. High Temperature, High Power Piezoelectric Composite Transducers

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  5. High energy neutron source for materials research and development

    International Nuclear Information System (INIS)

    Odera, M.

    1989-01-01

    Requirements for neutron source for nuclear materials research are reviewed and ESNIT, Energy Selective Neutron Irradiation Test facility proposed by JAERI is discussed. Its principal aims of a wide neutron energy tunability and spectra peaking at each energy to enable characterization of material damage process are demanding but attractive goals which deserve detailed study. It is also to be noted that the requirements make a difference in facility design from those of FMIT, IFMIF and other high energy intense neutron sources built or planned to date. Areas of technologies to be addressed to realize the ESNIT facility are defined and discussed. In order to get neutron source having desired spectral characteristics keeping moderate intensity, projectile and target combinations must be examined including experimentation if necessary. It is also desired to minimize change of flux density and energy spectrum according to location inside irradiation chamber. Extended target or multiple targets configuration might be a solution as well as specimen rotation and choice of combination of projectile and target which has minimum velocity of the center of mass. Though relevant accelerator technology exists, it is to be stressed that considerable efforts must be paid, especially in the area of target and irradiation devices to get ESNIT goal. Design considerations to allow hands-on maintenance and future upgrading possibility are important either, in order to exploit the facility fully for nuclear materials research and development. (author)

  6. High Power Electron Accelerator Prototype

    CERN Document Server

    Tkachenko, Vadim; Cheskidov, Vladimir; Korobeynikov, G I; Kuznetsov, Gennady I; Lukin, A N; Makarov, Ivan; Ostreiko, Gennady; Panfilov, Alexander; Sidorov, Alexey; Tarnetsky, Vladimir V; Tiunov, Michael A

    2005-01-01

    In recent time the new powerful industrial electron accelerators appear on market. It caused the increased interest to radiation technologies using high energy X-rays due to their high penetration ability. However, because of low efficiency of X-ray conversion for electrons with energy below 5 MeV, the intensity of X-rays required for some industrial applications can be achieved only when the beam power exceeds 300 kW. The report describes a project of industrial electron accelerator ILU-12 for electron energy up to 5 MeV and beam power up to 300 kW specially designed for use in industrial applications. On the first stage of work we plan to use the existing generator designed for ILU-8 accelerator. It is realized on the GI-50A triode and provides the pulse power up to 1.5-2 MW and up to 20-30 kW of average power. In the report the basic concepts and a condition of the project for today are reflected.

  7. Effect of neutron irradiation on the breakdown voltage of power MOSFET's

    International Nuclear Information System (INIS)

    Hasan, S.M.Y.; Kosier, S.L.; Schrimpf, R.D.; Galloway, K.F.

    1994-01-01

    The effect of neutron irradiation on power metal-oxide-semiconductor field effect transistor (power MOSFET) breakdown voltage has been investigated. Transistors with various breakdown voltage ratings were irradiated in a TRIGA nuclear reactor with cumulative fluence levels up to 5 x 10 14 neutrons/cm 2 (1 MeV equivalent). Noticeable increases in the breakdown voltages are observed in n-type MOSFET's after 10 13 neutrons/cm 2 and in p-type MOSFETs after 10 12 neutrons/cm 2 . An increase in breakdown voltage of as much as 30% is observed after 5 x 10 14 neutrons/cm 2 . The increase in breakdown voltage is attributed to the neutron-irradiation-induced defects which decrease the mean free path and trap majority carriers in the space charge region. The effect of positive trapped oxide charge due to concomitant gamma radiation and the effect of the termination structure on the increase in breakdown voltage are considered. An empirical model is presented to predict the value of the breakdown voltage as a function of neutron fluence

  8. High-pressure 3He gas scintillation neutron spectrometer

    International Nuclear Information System (INIS)

    Derzon, M.S.; Slaughter, D.R.; Prussin, S.G.

    1985-10-01

    A high-pressure, 3 He-Xe gas scintillation spectrometer has been developed for neutron spectroscopy on D-D fusion plasmas. The spectrometer exhibits an energy resolution of (121 +- 20 keV) keV (FWHM) at 2.5 MeV and an efficiency of (1.9 +- 0.4) x 10 -3 (n/cm 2 ) -1 . The contribution to the resolution (FWHM) from counting statistics is only (22 +- 3 keV) and the remainder is due predominantly to the variation of light collection efficiency with location of neutron events within the active volume of the detector

  9. High-resolution neutron-diffraction measurements to 8 kbar

    Science.gov (United States)

    Bull, C. L.; Fortes, A. D.; Ridley, C. J.; Wood, I. G.; Dobson, D. P.; Funnell, N. P.; Gibbs, A. S.; Goodway, C. M.; Sadykov, R.; Knight, K. S.

    2017-10-01

    We describe the capability to measure high-resolution neutron powder diffraction data to a pressure of at least 8 kbar. We have used the HRPD instrument at the ISIS neutron source and a piston-cylinder design of pressure cell machined from a null-scattering titanium zirconium alloy. Data were collected under hydrostatic conditions from an elpasolite perovskite La?NiMnO?; by virtue of a thinner cell wall on the incident-beam side of the cell, it was possible to obtain data in the instrument's highest resolution back-scattering detector banks up to a maximum pressure of 8.5 kbar.

  10. High precision neutron interferometer setup S18b

    International Nuclear Information System (INIS)

    Hasegawa, Y.; Lemmel, H.

    2011-01-01

    The present setup at S18 is a multi purpose instrument. It is used for both interferometry and a Bonse-Hart camera for USANS (Ultra Small Angle Neutron Scattering) spectroscopy with wide range tunability of wavelength. Some recent measurements demand higher stability of the instrument, which made us to propose a new setup dedicated particularly for neutron interferometer experiments requiring high phase stability. To keep both options available, we suggest building the new setup in addition to the old one. By extending the space of the present setup by 1.5 m to the upstream, both setups can be accommodated side by side. (authors)

  11. Low level neutron monitoring using high pressure 3He detectors

    International Nuclear Information System (INIS)

    Pszona, S.

    1995-01-01

    Three detectors, two spherical proportional counters and an ionisation chamber, all filled with 3 He to pressures of 160 kPa, 325 kPa and 1 MPa respectively have been experimentally studied with respect to their use for low level neutron monitoring. The ambient dose equivalent responses and the energy resolutions of these detectors have been determined. It is shown that spectral analysis of the signals from these detectors not only gives high sensitivity with regard to ambient dose equivalent but also improves the quality of the measurements. A special instrumentation for low level neutron monitoring is described in which a quality control method has been implemented. (Author)

  12. Neutron analysis of the fuel of high temperature nuclear reactors

    International Nuclear Information System (INIS)

    Bastida O, G. E.; Francois L, J. L.

    2014-10-01

    In this work a neutron analysis of the fuel of some high temperature nuclear reactors is presented, studying its main features, besides some alternatives of compound fuel by uranium and plutonium, and of coolant: sodium and helium. For this study was necessary the use of a code able to carry out a reliable calculation of the main parameters of the fuel. The use of the Monte Carlo method was convenient to simulate the neutrons transport in the reactor core, which is the base of the Serpent code, with which the calculations will be made for the analysis. (Author)

  13. Properties of neutron-rich hafnium high-spin isomers

    CERN Multimedia

    Tungate, G; Walker, P M; Neyens, G; Billowes, J; Flanagan, K; Koester, U H; Litvinov, Y

    It is proposed to study highly-excited multi-quasiparticle isomers in neutron-rich hafnium (Z=72) isotopes. Long half-lives have already been measured for such isomers in the storage ring at GSI, ensuring their accessibility with ISOL production. The present proposal focuses on:\\\\ (i) an on-line experiment to measure isomer properties in $^{183}$Hf and $^{184}$Hf, and\\\\ (ii) an off-line molecular breakup test using REXTRAP, to provide Hf$^{+}$ beams for future laser spectroscopy and greater sensitivity for the future study of more neutron-rich isotopes.

  14. Neutron spin echo and high resolution inelastic spectroscopy

    International Nuclear Information System (INIS)

    Mezei, F.; Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics)

    1982-01-01

    The principles of neutrons spin echo (NSE) technique are considered. It is shown that the basis of NSE principle is a single step measurement of the change of the neutron velocity in the scattering process. The backscattering soectroscopy and the NSE techniques are compared. The NSF spectrometer is described. It is shown that 0.5 MeV energy resolution achieved in the NSE experiment is about 40 times superior to those achieved by the other techniques. The NSE technique has the unique feature that provides high resolution in neutron energy change independently of the monochromatization of the beam. The NSE instrument not only covers a wider dynamic range on a pulsed source that on a continuous one, but also collects data more efficiently

  15. Nuclear radiation detectors using high resistivity neutron transmutation doped silicon

    International Nuclear Information System (INIS)

    Gessner, T.; Irmer, K.

    1983-01-01

    A method for the production of semiconductor detectors based on high resistivity n-type silicon is described. The n-type silicon is produced by neutron irradiation of p-type silicon. The detectors are produced by planar technique. They are suitable for the spectrometry of alpha particles and for the pulse count measurement of beta particles at room temperature. (author)

  16. The study of high precision neutron moisture gauge

    International Nuclear Information System (INIS)

    Liu Shengkang; Bao Guanxiong; Sang Hai; Zhu Yuzhen

    1993-01-01

    The principle, structure and calibration experiment of the high precision neutron moisture gauge (insertion type) are described. The gauge has been appraised. The precision of the measuring moisture of coke is lower than 0.5%, and the range of the measuring moisture is 2%-12%. The economic benefit of the gauge application is good

  17. Investigation of Acrylic Acid at High Pressure using Neutron Diffraction

    DEFF Research Database (Denmark)

    Johnston, Blair F.; Marshall, William G.; Parsons, Simon

    2014-01-01

    This article details the exploration of perdeuterated acrylic acid at high pressure using neutron diffraction. The structural changes that occur in acrylic acid-d4 are followed via diffraction and rationalised using the Pixel method. Acrylic acid undergoes a reconstructive phase transition to a new...

  18. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction

    DEFF Research Database (Denmark)

    Marshall, William G.; Urquhart, Andrew; Oswald, Iain D. H.

    2015-01-01

    This article shows that pressure can be a low-intensity route to the synthesis of polymethacrylic acid. The exploration of perdeuterated methacrylic acid at high pressure using neutron diffraction reveals that methacrylic acid exhibits two polymorphic phase transformations at relatively low...

  19. High-fidelity MCNP modeling of a D-T neutron generator for active interrogation of special nuclear material

    International Nuclear Information System (INIS)

    Katalenich, Jeff; Flaska, Marek; Pozzi, Sara A.; Hartman, Michael R.

    2011-01-01

    Fast and robust methods for interrogation of special nuclear material (SNM) are of interest to many agencies and institutions in the United States. It is well known that passive interrogation methods are typically sufficient for plutonium identification because of a relatively high neutron production rate from 240 Pu . On the other hand, identification of shielded uranium requires active methods using neutron or photon sources . Deuterium-deuterium (2.45 MeV) and deuterium-tritium (14.1 MeV) neutron-generator sources have been previously tested and proven to be relatively reliable instruments for active interrogation of nuclear materials . In addition, the newest generators of this type are small enough for applications requiring portable interrogation systems. Active interrogation techniques using high-energy neutrons are being investigated as a method to detect hidden SNM in shielded containers . Due to the thickness of some containers, penetrating radiation such as high-energy neutrons can provide a potential means of probing shielded SNM. In an effort to develop the capability to assess the signal seen from various forms of shielded nuclear materials, University of Michigan Neutron Science Laboratory's D-T neutron generator and its shielding were accurately modeled in MCNP. The generator, while operating at nominal power, produces approximately 1x10 10 neutrons/s, a source intensity which requires a large amount of shielding to minimize the dose rates around the generator. For this reason, the existing shielding completely encompasses the generator and does not include beam ports. Therefore, several MCNP simulations were performed to estimate the yield of uncollided 14.1-MeV neutrons from the generator for active interrogation experiments. Beam port diameters of 5, 10, 15, 20, and 25 cm were modeled to assess the resulting neutron fluxes. The neutron flux outside the beam ports was estimated to be approximately 2x10 4 n/cm 2 s.

  20. A compact fast-neutron producing target for high resolution cross section measurements

    NARCIS (Netherlands)

    Flaska, M.

    2006-01-01

    A proper knowledge of neutron cross sections is very important for the operation safety of various nuclear facilities. Reducing uncertainties in the neutron cross sections can lead to an enhanced safety of present and future nuclear power systems. Accurate neutron cross sections also play a relevant

  1. A study on the sensitivity of self-powered neutron detectors(SPNDs)

    International Nuclear Information System (INIS)

    Lee, Wan No

    1997-02-01

    Self-Powered Neutron Detectors(SPND) are currently used to estimate the power generation distribution and fuel burn-up in several nuclear power reactors in Korea. While they have several advantages such as small size, low cost, and relatively simple electronics required in conjunction with those usage, they have some intrinsic problems of the low level of output current, a slow response time, the rapid change of sensitivity which makes it difficult to use for a long term. In this paper, Monte Carlo simulation is accomplished to calculate the escape probability as a function of the birth position of emitted beta particle for a geometry of rhodium-based SPNDs. A simple numerical method calculates the initial generation rate of beta particles and the change of generation rate due to rhodium burn-up. Using the simulation result, the burn-up profile of rhodium number density and the neutron sensitivity are calculated as a function of burn-up time in reactors. The sensitivity of the SPND decreases non-linearly due to the high absorption cross-section and the non-uniform burn-up of rhodium in the emitter rod. In addition, for improvement of some properties of rhodium-based SPNDs which are currently used, this paper presents a new material and modified geometry. From searching nuclear data, Ag 109 is chosen as a replacing material for rhodium. Silver has a low neutron absorption cross-section and a high beta energy and a low density when it is compared with rhodium. The sensitivity and the density change of silver as a function of burn-up are calculated using this method. Also, this paper compares the initial sensitivity of a solid type with its of a tube type. The initial sensitivity is increased with the new material and the tube type. Silver is also found to be used for longer time than rhodium. The method used here can be applied to the analysis of other types of SPNDs and will be useful in the optimum design of new SPNDs for long term usage

  2. A highly-segmented neutron detector for the A1 experiment at MAMI

    Energy Technology Data Exchange (ETDEWEB)

    Schoth, Matthias [Institut fuer Kernphysik, Mainz (Germany); Collaboration: A1-Collaboration

    2015-07-01

    Electric and magnetic form factors of the neutron, are one of the defining properties to characterize its structure quantitatively. A planned physics program to improve the data base significantly requires high performance detection of relativistic neutrons. Exploiting the full potential of the high luminosity supplied by the MAMI accelerator, a novel neutron detector is being developed in the scope of the A1 collaboration. A large active detector volume of 0.96 m{sup 3} is required to achieve a high raw detection efficiency. The detector is subdivided into 2048 plastic scintillators to be able to cope with high background rates. The light is extracted via wavelength shifting fibres and then guided to multi anode photomultiplier. The signal is read out with FPGA based TDCs (TRBv3 developed at GSI). The energy of the signal is obtained via time over threshold information in combination with a suitable shaping and discriminating circuit. Prototype tests have been performed to optimize the choice of materials and geometry. The capability to detect neutrons in the relevant momentum range has been demonstrated using pion production. A Geant4 simulation using tracking algorithms evaluating the deposited energy is able to optimize key detector properties like particle id efficiency, multiplicity or the effective analyzing power for double polarized scattering experiments.

  3. Neutron-deuteron analyzing power data at En = 21 MeV and the energy dependence of the three-nucleon analyzing power puzzle

    Science.gov (United States)

    Weisel, G. J.; Tornow, W.; Esterline, J. H.

    2015-08-01

    We present measurements of n-d analyzing power, {A}y(θ ), at En = 21.0 MeV. The experiment produces neutrons via the 2H(d, n)3He reaction and uses a deuterated liquid-scintillator center detector and six pairs of liquid-scintillator neutron side detectors. Elastic neutron scattering events are identified by using time-of-flight techniques and by setting a gate in the center-detector pulse-height spectrum. Beam polarization is monitored by using a high-pressure helium gas scintillator. The n-d {A}y(θ ) data at 21.0 MeV show a significant discrepancy with the results of rigorous three-body calculations and are consistent with data taken previously by us at 19.0 and 22.5 MeV. We review the overall energy dependence of the three-nucleon analyzing power puzzle in neutron-deuteron elastic scattering, using the best data available. We find that the relative difference between calculations and data is nearly constant at 25% up to En = 22.5 MeV.

  4. Neutron dosimetry inside the containment building of Spanish nuclear power plants with PADC based dosemeters

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Fuste, M.J. [Grup de Fisica de les Radiacions. Departament de Fisica. Edifici C. Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Domingo, C., E-mail: carles.domingo@uab.ca [Grup de Fisica de les Radiacions. Departament de Fisica. Edifici C. Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Amgarou, K.; Bouassoule, T.; Castelo, J. [Grup de Fisica de les Radiacions. Departament de Fisica. Edifici C. Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain)

    2009-10-15

    The Spanish Nuclear Safety Council (Consejo de Seguridad Nuclear, CSN) recommends performing neutron individual dose assignments at workplaces based on ambient dose equivalent measurements using area monitors and by estimating the amount of time that workers spend in the different monitored environments. In addition, some Spanish nuclear power plants estimate the neutron dose equivalent using albedo thermoluminescence dosemeters (TLD). In the period 2004-2006, our group, together with other research centers, participated in a project, funded by the CSN, with the support of the Spanish Nuclear Power Plants Association (UNESA), to investigate in situ which could be the best practical procedure for individual neutron dose monitoring in nuclear power plants. As part of this survey, several units of the UAB PADC based neutron dosemeter were exposed, on a methacrylate phantom simulating a human body, at four different places inside the containment building of the Asco I nuclear power plant. The influence of different types of calibration neutron fields is analysed and the dose equivalent for each point is estimated.

  5. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    International Nuclear Information System (INIS)

    Schwarze, G.E.; Frasca, A.J.

    1994-01-01

    The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10 13 n/cm 2 and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed

  6. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    Science.gov (United States)

    Schwarze, G. E.; Frasca, A. J.

    1991-01-01

    The effects of neutron and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10(exp 13) n/sq cm and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are presented. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  7. Solid State Track Recorder fission rate measurements at high neutron fluence and high temperature

    International Nuclear Information System (INIS)

    Ruddy, F.H.; Roberts, J.H.; Gold, R.

    1985-01-01

    Solid State Track Recorder (SSTR) techniques have been used to measure 239-Pu, 235-U, and 237-Np fission rates for total neutron fluences approaching 5 x 10 17 n/cm 2 at temperatures in the range 680 to 830 0 F. Natural quartz crystal SSTRs were used to withstand the high temperature environment and ultra low-mass fissionable deposits of the three isotopes were required to yield scannable track densities at the high neutron fluences. The results of these high temperature, high neutron fluence measurements are reported

  8. Neutron diffraction studies of high-T/sub c/ superconductors

    International Nuclear Information System (INIS)

    Jorgensen, J.D.

    1988-03-01

    Neutron powder diffraction techniques have been used extensively for the study of high-T/sub c/ oxide superconductors because of the need to locate oxygen atoms and accurately determine the oxygen site occupancies, and the difficulty in obtaining single crystals. For example, in the case of YBa 2 Cu 3 O/sub 7-δ/, neutron powder diffraction and Rietveld structural refinement were used to obtain the first complete structural information. Subsequent experiments focussed on determining the relationship of superconducting properties to the number and distribution of oxygen vacancies on the Cu-O sublattice with measurements being done on samples in thermodynamic equilibrium, at high temperature in controlled oxygen atmospheres, and on metastable, oxygen-deficient samples produced by quenching. Neutron powder diffraction has also been used to determine the structures of compounds in which the properties have been modified by substitution on the Y, Ba, or Cu sites. This paper briefly reviews some of the neutron powder diffraction results in these areas. 17 refs

  9. Monte Carlo simulation for neutron yield produced by bombarding thick targets with high energy heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Oranj, Leila Mokhtari; Oh, Joo Hee; Yoon, Moo Hyun; Lee, Hee Seock [POSTECH, Pohang (Korea, Republic of)

    2013-04-15

    One of radiation shielding issues at heavy-ion accelerator facilities is to estimate neutron production by primary heavy ions. A few Monte Carlo transport codes such as FLUKA and PHITS can work with primary heavy ions. Recently IBS/RISP((Rare Isotope Science Project) started to design a high-energy, high-power rare isotope accelerator complex for nuclear physics, medical and material science and applications. There is a lack of experimental and simulated data about the interaction of major beam, {sup 238}U with materials. For the shielding design of the end of first accelerating section section, we calculate a differential neutron yield using the FLUKA code for the interaction of 18.5 MeV/u uranium ion beam with thin carbon stripper of 1.3 μm). The benchmarking studies were also done to prove the yield calculation for 400 MeV/n {sup 131}Xe and other heavy ions. In this study, the benchmarking for Xe-C, Xe-Cu, Xe-Al, Xe-Pb and U-C, other interactions were performed using the FLUKA code. All of results show that the FLUKA can evaluate the heavy ion induced reaction with good uncertainty. For the evaluation of neutron source term, the calculated neutron yields are shown in Fig. 2. The energy of Uranium ion beam is only 18.5 MeV/u, but the energy of produced secondary neutrons was extended over 100 MeV. So the neutron shielding and the damage by those neutrons is expected to be serious. Because of thin stripper, the neutron intensity at forward direction was high. But the the intensity of produced secondary photons was relatively low and mostly the angular property was isotropic. For the detail shielding design of stripper section of RISP rare istope accelerator, the benchmarking study and preliminary evaluation of neutron source term from uranium beam have been carried out using the FLUKA code. This study is also compared with the evaluation results using the PHITS code performed coincidently. Both studies shows that two monte carlo codes can give a good results for

  10. Practical neutron dosimetry at high energies

    International Nuclear Information System (INIS)

    McCaslin, J.B.; Thomas, R.H.

    1980-10-01

    Dosimetry at high energy particle accelerators is discussed with emphasis on physical measurements which define the radiation environment and provide an immutable basis for the derivation of any quantities subsequently required for risk evaluation. Results of inter-laboratory dosimetric comparisons are reviewed and it is concluded that a well-supported systematic program is needed which would make possible detailed evaluations and inter-comparisons of instruments and techniques in well characterized high energy radiation fields. High-energy dosimetry is so coupled with radiation transport that it is clear their study should proceed concurrently

  11. Application of the neutron noise analysis technique in nuclear power plants

    International Nuclear Information System (INIS)

    Lescano, Victor H.; Wentzeis, Luis M.

    1999-01-01

    Using the neutron noise analysis in nuclear power plants, and without producing any perturbation in the normal operation of the plant, information of the vibration state of the reactor internals and the behavior of the operating conditions of the reactor primary circuit can be obtained. In Argentina, the neutron noise analysis technique is applied in customary way in the nuclear power plants Atucha I and Embalse. A database was constructed and vibration frequencies corresponding to different reactor internals were characterized. Reactor internals with particular mechanical vibrations have been detected and localized. In the framing of a cooperation project between Argentina and Germany, we participated in the measurements, analysis and modelisation, using the neutron noise technique, in the Obrigheim and Gundremmingen nuclear power plants. In the nuclear power plant Obrigheim (PWR, 350 M We), correlations between the signals measured from self-power neutron detectors and accelerometers located inside the reactor core, were made. In the nuclear power plant Gundremmingen (BWR, 1200 M We) we participated in the study of a particular mechanical vibration detected in one of the instrumentation tube. (author)

  12. High-level neutron coincidence counter (HLNCC): users' manual

    International Nuclear Information System (INIS)

    Krick, M.S.; Menlove, H.O.

    1979-06-01

    This manual describes the portable High-Level Neutron Coincidence Counter (HLNCC) developed at the Los Alamos Scientific Laboratory (LASL) for the assay of plutonium, particularly by inspectors of the International Atomic Energy Agency (IAEA). The counter is designed for the measurement of the effective 240 Pu mass in plutonium samples which may have a high plutonium content. The following topics are discussed: principle of operation, description of the system, operating procedures, and applications

  13. Practical conditions in the neutron diffraction under high pressure

    International Nuclear Information System (INIS)

    Kamigaki, Kazuo; Ohashi, Masayoshi

    1993-01-01

    Practical analysis is made on some conditions in utilizing neutrons for the study of atomistic structure of materials under high pressure. Investigation is made on the geometrical conditions; size of the specimen, width of slits, and the rate of extra-scattering. Experiments are performed on the effects of absorption by high pressure cell and the disturbance due to an overlapping of diffraction peaks. An observation is presented on the pressure-induced transformation in RbBr. (author)

  14. Power measurement in the boiling capsules in R2 using delayed neutron detector

    International Nuclear Information System (INIS)

    Roennberg, G.

    1979-03-01

    LWR fuel testing is performed in the R2 reactor by irradiation in both loops and so-called boiling capsules. The loops have forced cooling, and the power can be measured calorimetrically by conventional instrumentation. The boiling capsules have convection cooling, and it has therefore been necessary to develop a special technique for power measurement, the delayed neutron detector (DND). The DND is a pneumatic rabbit system, which activates small uranium samples in the boiling capsules and counts the delayed neutrons for determination of the fission rate. This report describes the equipment used, the procedure of measurement, and the method of evaluation. (atuhor)

  15. Detection of low caloric power of coal by pulse fast-thermal neutron analysis

    International Nuclear Information System (INIS)

    Gu De-shan; Sang Hai-feng; Qiao Shuang; Liu Yu-ren, Liu Lin-mao; Jing Shi-wei; Chinese Academy of Sciences, Changchun

    2004-01-01

    Analysis method and principle of pulse fast-thermal neutron analysis (PFTNA) are introduced. A system for the measurement of low caloric power of coal by PFTNA is also presented. The 14 MeV pulse neutron generator and BGO detector and 4096 MCA were applied in this system. A multiple linear regression method applied to the data solved the interferential problem of multiple elements. The error of low caloric power between chemical analysis and experiment was less than 0.4 MJ/kg. (author)

  16. Neuro-diffuse algorithm for neutronic power identification of TRIGA Mark III reactor

    International Nuclear Information System (INIS)

    Rojas R, E.; Benitez R, J. S.; Segovia de los Rios, J. A.; Rivero G, T.

    2009-10-01

    In this work are presented the results of design and implementation of an algorithm based on diffuse logic systems and neural networks like method of neutronic power identification of TRIGA Mark III reactor. This algorithm uses the punctual kinetics equation as data generator of training, a cost function and a learning stage based on the descending gradient algorithm allow to optimize the parameters of membership functions of a diffuse system. Also, a series of criteria like part of the initial conditions of training algorithm are established. These criteria according to the carried out simulations show a quick convergence of neutronic power estimated from the first iterations. (Author)

  17. Self-Powered Neutron Detector Calibration Using a Large Vertical Irradiation Hole of HANARO

    OpenAIRE

    Kim Myong-Seop; Park Byung-Gun; Kang Gi-Doo

    2018-01-01

    A calibration technology of the self-powered neutron detectors (SPNDs) using a large vertical irradiation hole of HANARO is developed. The 40 Rh-SPNDs are installed on the polycarbonate plastic support, and the gold wires with the same length as the effective length of the rhodium emitter of the SPND are also installed to measure the neutron flux on the SPND. They are irradiated at a low reactor power, and the SPND current is measured using the pico-ammeter. The external gamma-rays which affe...

  18. Levitation apparatus for neutron diffraction investigations on high temperature liquids

    International Nuclear Information System (INIS)

    Hennet, Louis; Pozdnyakova, Irina; Bytchkov, Aleksei; Cristiglio, Viviana; Palleau, Pierre; Fischer, Henry E.; Cuello, Gabriel J.; Johnson, Mark; Melin, Philippe; Zanghi, Didier; Brassamin, Severine; Brun, Jean-Francois; Price, David L.; Saboungi, Marie-Louise

    2006-01-01

    We describe a new high temperature environment based on aerodynamic levitation and laser heating designed for neutron scattering experiments up to 3000 deg. C. The sample is heated to the desired temperature with three CO 2 lasers from different directions in order to obtain a homogeneous temperature distribution. The apparent temperature of the sample is measured with an optical pyrometer, and two video cameras are employed to monitor the sample behavior during heating. The levitation setup is enclosed in a vacuum-tight chamber, enabling a high degree of gas purity and a reproducible sample environment for structural investigations on both oxide and metallic melts. High-quality neutron diffraction data have been obtained on liquid Y 3 Al 5 O 12 and ZrNi alloy for relatively short counting times (1.5 h)

  19. Experimental and mathematical simulation techniques for determining an in-situ response testing method for neutron sensors used in reactor power plant protection systems

    International Nuclear Information System (INIS)

    Behbahani, A.

    1983-01-01

    An analytical neutron sensor response model and methods for transient response measurements of neutron sensors (compensated ionization chamber), including possible in-situ techniques have been developed and evaluated to meet the provisions of Draft Standard ISA Sd67.06, IEEE 338-1977, and NRC Guide 1.118. One in-situ method requires the perturbation of the high voltage detector (sensor) power supply and measurement of the sensor response. The response to a perturbation of the power supply is related to the response of the sensor to a transient change in neutron flux. Random signal analysis is another in-situ technique to monitor the neutron sensor response. In this method the power spectrum of the inherent fluctuations from the neutron sensor output (current in CIC) are measured and evaluated. Transient response techniques (including in-situ methods) are experimentally and analytically evaluated to identify the mechanisms which may cause degradation in the response of the neutron sensors. The objective of the experimental evaluation was to correlate the measured response time using transient radiation flux changes and power supply perturbation. The objective of the analytical model of the different sensor response was to predict response time and degradation mechanisms

  20. An investigation of models of rhodium emitter used in self-powered neutron detector

    International Nuclear Information System (INIS)

    Borisenko, V.I.; Piontkovskij, Yu.F.; Goranchuk, V.V.

    2017-01-01

    he paper presents the results of MCNP simulation of the self-powered neutron detector (SPND) signal formation as a result of emitter nuclei activation under the irradiation with neutrons generated in the fuel assemblies. To account for the non-uniformity of emitter burnup along the radius, its model was divided radially into 10 layers of equal thickness. It has been shown that the main contribution of about 88 % of SPND signal is provided by the four peripheral emitter layers. The contribution of different parts of emitter to the SPND signal formation throughout the lifetime of the SPND in the In-Core Monitoring System was found. Simulation results allow us to determine the SPND signal when the spectral characteristics of the neutron flux at the detector location change during the fuel campaign. The study has investigated and proposed a SPND model with the higher neutron sensitivity even though a smaller amount of expensive rhodium is used.

  1. Large-area self-powered neutron-detectors for neutron-flux measurements in HTRs. Status of developmental work

    International Nuclear Information System (INIS)

    Brixy, H.; Hecker, R.; Serpekian, T.; Benninghofen, G.; Serafin, N.; Spillekothen, H.G.

    1982-06-01

    The development is described of the large-area SPN-detector as an out of core power monitoring system. Gadolinium or cobalt was used as the emitter. Response functions of the gadolinium SPN-detector were found with regard to the reactor power, the effect of the gamma field, its short-term behaviour following reactor shutdown and long-term behaviour during reactor operation. It was shown that a detector of 0.1 mm emitter thickness can withstand an integral thermal neutron flux of 2.10 20 nvt almost without efficiency loss thus indicating that the large-area gadolinium SPN-detector is a suitable means for power monitoring in large HTGR's

  2. Neutron scattering investigation of magnetic excitations at high energy transfers

    International Nuclear Information System (INIS)

    Loong, C.K.

    1984-01-01

    With the advance of pulsed spallation neutron sources, neutron scattering investigation of elementary excitations in magnetic materials can now be extended to energies up to several hundreds of MeV. We have measured, using chopper spectrometers and time-of-flight techniques, the magnetic response functions of a series of d and f transition metals and compounds over a wide range of energy and momentum transfer. In PrO 2 , UO 2 , BaPrO 3 and CeB 6 we observed crystal-field transitions between the magnetic ground state and the excited levels in the energy range from 40 to 260 MeV. In materials exhibiting spin-fluctuation or mixed-valent character such as Ce 74 Th 26 , on the other hand, no sharp crystal-field lines but a broadened quasielastic magnetic peak was observed. The line width of the quasielastic component is thought to be connected to the spin-fluctuation energy of the 4f electrons. The significance of the neutron scattering results in relation to the ground state level structure of the magnetic ions and the spin-dynamics of the f electrons is discussed. Recently, in a study of the spin-wave excitations in itinerant magnetic systems, we have extended the spin-wave measurements in ferromagnetic iron up to about 160 MeV. Neutron scattering data at high energy transfers are of particular interest because they provide direct comparison with recent theories of itinerant magnetism. 26 references, 7 figures

  3. Validation of SCALE code package on high performance neutron shields

    International Nuclear Information System (INIS)

    Bace, M.; Jecmenica, R.; Smuc, T.

    1999-01-01

    The shielding ability and other properties of new high performance neutron shielding materials from the KRAFTON series have been recently published. A comparison of the published experimental and MCNP results for the two materials of the KRAFTON series, with our own calculations has been done. Two control modules of the SCALE-4.4 code system have been used, one of them based on one dimensional radiation transport analysis (SAS1) and other based on the three dimensional Monte Carlo method (SAS3). The comparison of the calculated neutron dose equivalent rates shows a good agreement between experimental and calculated results for the KRAFTON-N2 material.. Our results indicate that the N2-M-N2 sandwich type is approximately 10% inferior as neutron shield to the KRAFTON-N2 material. All values of neutron dose equivalent obtained by SAS1 are approximately 25% lower in comparison with the SAS3 results, which indicates proportions of discrepancies introduced by one-dimensional geometry approximation.(author)

  4. High-Flux Neutron Generator Facility for Geochronology and Nuclear Physics Research

    Science.gov (United States)

    Waltz, Cory; HFNG Collaboration

    2015-04-01

    A facility based on a next-generation, high-flux D-D neutron generator (HFNG) is being commissioned at UC Berkeley. The generator is designed to produce monoenergetic 2.45 MeV neutrons at outputs exceeding 1011 n/s. The HFNG is designed around two RF-driven multi-cusp ion sources that straddle a titanium-coated copper target. D + ions, accelerated up to 150 keV from the ion sources, self-load the target and drive neutron generation through the d(d,n)3 He fusion reaction. A well-integrated cooling system is capable of handling beam power reaching 120 kW impinging on the target. The unique design of the HFNG target permits experimental samples to be placed inside the target volume, allowing the samples to receive the highest neutron flux (1011 cm-2 s-1) possible from the generator. In addition, external beams of neutrons will be available simultaneously, ranging from thermal to 2.45 MeV. Achieving the highest neutron yields required carefully designed schemes to mitigate back-streaming of high energy electrons liberated from the cathode target by deuteron bombardment. The proposed science program is focused on pioneering advances in the 40 Ar/39 Ar dating technique for geochronology, new nuclear data measurements, basic nuclear science, and education. An end goal is to become a user facility for researchers. This work is supported by NSF Grant No. EAR-0960138, U.S. DOE LBNL Contract No. DE-AC02-05CH11231, U.S. DOE LLNL Contract No. DE-AC52-07NA27344, and UC Office of the President Award 12-LR-238745.

  5. Neutron physics of a high converting advanced pressurized water reactor

    International Nuclear Information System (INIS)

    Berger, H.D.

    1985-01-01

    The neutron physics of an APWR are analysed by single pin-cell calculations as well as two-dimensional whole-reactor computations. The calculational methods of the two codes employed for this study, viz. the cell code SPEKTRA and the diffusion-burnup code DIBU, are presented in detail. The APWR-investigations carried out concentrate on the void coefficient characteristics of tight UO 2 /PuO 2 -lattices, control rod worths, burnup behaviour and spatial power distributions in APWR cores. The principal physics design differences between advanced pressurized water reactors and present-day PWRs are identified and discussed. (orig./HP) [de

  6. Thermal neutron flux measurement using self-powered neutron detector (SPND) at out-core locations of TRIGA PUSPATI Reactor (RTP)

    Science.gov (United States)

    Ali, Nur Syazwani Mohd; Hamzah, Khaidzir; Mohamad Idris, Faridah; Hairie Rabir, Mohamad

    2018-01-01

    The thermal neutron flux measurement has been conducted at the out-core location using self-powered neutron detectors (SPNDs). This work represents the first attempt to study SPNDs as neutron flux sensor for developing the fault detection system (FDS) focusing on neutron flux parameters. The study was conducted to test the reliability of the SPND’s signal by measuring the neutron flux through the interaction between neutrons and emitter materials of the SPNDs. Three SPNDs were used to measure the flux at four different radial locations which located at the fission chamber cylinder, 10cm above graphite reflector, between graphite reflector and tank liner and fuel rack. The measurements were conducted at 750 kW reactor power. The outputs from SPNDs were collected through data acquisition system and were corrected to obtain the actual neutron flux due to delayed responses from SPNDs. The measurements showed that thermal neutron flux between fission chamber location near to the tank liner and fuel rack were between 5.18 × 1011 nv to 8.45 × 109 nv. The average thermal neutron flux showed a good agreement with those from previous studies that has been made using simulation at the same core configuration at the nearest irradiation facilities with detector locations.

  7. Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Verma, V., E-mail: vasudha.verma@physics.uu.se [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Barbot, L.; Filliatre, P. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Hellesen, C. [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden); Jammes, C. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 St-Paul-lez-Durance (France); Svärd, S. Jacobsson [Division of Applied Nuclear Physics, Uppsala University, Box 516, SE-75120 Uppsala (Sweden)

    2017-07-11

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment. - Highlights: • Studied possibility of using SPNDs as in-core detectors in SFRs. • Study done to detect local power profile changes when reactor is at nominal power. • SPND with a Pt-emitter gives measurable prompt current of the order of 600 nA/m. • Dominant proportion of prompt response is maintained throughout the operation. • Detector signal gives dynamic information on the power fluctuations.

  8. Intense fusion neutron sources

    International Nuclear Information System (INIS)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-01-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 10 15 -10 21 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 10 20 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  9. Intense fusion neutron sources

    Science.gov (United States)

    Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

    2010-04-01

    The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

  10. High Flux Isotope Reactor cold neutron source reference design concept

    International Nuclear Information System (INIS)

    Selby, D.L.; Lucas, A.T.; Hyman, C.R.

    1998-05-01

    In February 1995, Oak Ridge National Laboratory's (ORNL's) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH 2 ) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH 2 cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept

  11. High Flux Isotope Reactor cold neutron source reference design concept

    Energy Technology Data Exchange (ETDEWEB)

    Selby, D.L.; Lucas, A.T.; Hyman, C.R. [and others

    1998-05-01

    In February 1995, Oak Ridge National Laboratory`s (ORNL`s) deputy director formed a group to examine the need for upgrades to the High Flux Isotope Reactor (HFIR) system in light of the cancellation of the Advanced neutron Source Project. One of the major findings of this study was that there was an immediate need for the installation of a cold neutron source facility in the HFIR complex. In May 1995, a team was formed to examine the feasibility of retrofitting a liquid hydrogen (LH{sub 2}) cold source facility into an existing HFIR beam tube. The results of this feasibility study indicated that the most practical location for such a cold source was the HB-4 beam tube. This location provides a potential flux environment higher than the Institut Laue-Langevin (ILL) vertical cold source and maximizes the space available for a future cold neutron guide hall expansion. It was determined that this cold neutron beam would be comparable, in cold neutron brightness, to the best facilities in the world, and a decision was made to complete a preconceptual design study with the intention of proceeding with an activity to install a working LH{sub 2} cold source in the HFIR HB-4 beam tube. During the development of the reference design the liquid hydrogen concept was changed to a supercritical hydrogen system for a number of reasons. This report documents the reference supercritical hydrogen design and its performance. The cold source project has been divided into four phases: (1) preconceptual, (2) conceptual design and testing, (3) detailed design and procurement, and (4) installation and operation. This report marks the conclusion of the conceptual design phase and establishes the baseline reference concept.

  12. Effects of high thermal neutron fluences on Type 6061 aluminum

    International Nuclear Information System (INIS)

    Weeks, J.R.; Czajkowski, C.J.; Farrell, K.

    1992-01-01

    The control rod drive follower tubes of the High Flux Beam Reactor are contructed from precipitation-hardened 6061-T6 aluminum alloy and they operate in the high thermal neutron flux regions of the core. It is shown that large thermal neutron fluences up to ∼4 x 10 23 n/cm 2 at 333K cause large increases in tensile strength and relatively modest decreases in tensile elongation while significantly reducing the notch impact toughness at room temperature. These changes are attributed to the development of a fine distribution of precipitates of amorphous silicon of which about 8% is produced radiogenically. A proposed role of thermal-to-fast flux ratio is discussed

  13. Neutron emission and fragment yield in high-energy fission

    International Nuclear Information System (INIS)

    Grudzevich, O. T.; Klinov, D. A.

    2013-01-01

    The KRIS special library of spectra and emission probabilities in the decays of 1500 nuclei excited up to energies between 150 and 250 MeV was developed for correctly taking into account the decay of highly excited nuclei appearing as fission fragments. The emission of neutrons, protons, and photons was taken into account. Neutron emission fromprimary fragments was found to have a substantial effect on the formation of yields of postneutron nuclei. The library was tested by comparing the calculated and measured yields of products originating from the fission of nuclei that was induced by high-energy protons. The method for calculating these yields was tested on the basis of experimental data on the thermal-neutroninduced fission of 235 U nuclei

  14. High average power solid state laser power conditioning system

    International Nuclear Information System (INIS)

    Steinkraus, R.F.

    1987-01-01

    The power conditioning system for the High Average Power Laser program at Lawrence Livermore National Laboratory (LLNL) is described. The system has been operational for two years. It is high voltage, high power, fault protected, and solid state. The power conditioning system drives flashlamps that pump solid state lasers. Flashlamps are driven by silicon control rectifier (SCR) switched, resonant charged, (LC) discharge pulse forming networks (PFNs). The system uses fiber optics for control and diagnostics. Energy and thermal diagnostics are monitored by computers

  15. Solution of the multilayer multigroup neutron diffusion equation in cartesian geometry by fictitious borders power method

    Energy Technology Data Exchange (ETDEWEB)

    Zanette, Rodrigo; Petersen, Caudio Zen [Univ. Federal de Pelotas, Capao do Leao (Brazil). Programa de Pos Graduacao em Modelagem Matematica; Schramm, Marcello [Univ. Federal de Pelotas (Brazil). Centro de Engenharias; Zabadal, Jorge Rodolfo [Univ. Federal do Rio Grande do Sul, Tramandai (Brazil)

    2017-05-15

    In this paper a solution for the one-dimensional steady state Multilayer Multigroup Neutron Diffusion Equation in cartesian geometry by Fictitious Borders Power Method and a perturbative analysis of this solution is presented. For each new iteration of the power method, the neutron flux is reconstructed by polynomial interpolation, so that it always remains in a standard form. However when the domain is long, an almost singular matrix arises in the interpolation process. To eliminate this singularity the domain segmented in R regions, called fictitious regions. The last step is to solve the neutron diffusion equation for each fictitious region in analytical form locally. The results are compared with results present in the literature. In order to analyze the sensitivity of the solution, a perturbation in the nuclear parameters is inserted to determine how a perturbation interferes in numerical results of the solution.

  16. Application of nuclear pumped laser to an optical self-powered neutron detector

    Science.gov (United States)

    Yamanaka, N.; Takahashi, H.; Iguchi, T.; Nakazawa, M.; Kakuta, T.; Yamagishi, H.; Katagiri, M.

    1996-05-01

    A Nuclear Pumped Laser (NPL) using 3He/Ne/Ar gas mixture is investigated for a purpose of applying to an optical self-powered neutron detector. Reactor experiments and simulations on lasing mechanism have been made to estimate the best gas pressure and mixture ratios on the threshold input power density (or thermal neutron flux) in 3He/Ne/Ar mixture. Calculational results show that the best mixture pressure is 3He/Ne/Ar=2280/60/100 Torr and thermal neutron flux threshold 5×1012 n/cm2 sec, while the reactor experiments made in the research reactor ``YAYOI'' of the University of Tokyo and ``JRR-4'' of JAERI also demonstrate that excitational efficiency is maximized in a similar gas mixture predicted by the calculation.

  17. High power microwave source development

    Science.gov (United States)

    Benford, James N.; Miller, Gabriel; Potter, Seth; Ashby, Steve; Smith, Richard R.

    1995-05-01

    The requirements of this project have been to: (1) improve and expand the sources available in the facility for testing purposes and (2) perform specific tasks under direction of the Defense Nuclear Agency about the applications of high power microwaves (HPM). In this project the HPM application was power beaming. The requirements of this program were met in the following way: (1) We demonstrated that a compact linear induction accelerator can drive HPM sources at repetition rates in excess of 100 HZ at peak microwave powers of a GW. This was done for the relativistic magnetron. Since the conclusion of this contract such specifications have also been demonstrated for the relativistic klystron under Ballistic Missile Defense Organization funding. (2) We demonstrated an L band relativistic magnetron. This device has been used both on our single pulse machines, CAMEL and CAMEL X, and the repetitive system CLIA. (3) We demonstrated that phase locking of sources together in large numbers is a feasible technology and showed the generation of multigigawatt S-band radiation in an array of relativistic magnetrons.

  18. Recent research on nuclear reaction using high-energy proton and neutron

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, Tokushi [Tokyo Univ., Tanashi (Japan). Inst. for Nuclear Study

    1997-11-01

    The presently available high-energy neutron beam facilities are introduced. Then some interesting research on nuclear reaction using high-energy protons are reported such as the intermediate mass fragments emission and neutron spectrum measurements on various targets. As the important research using high-energy neutron, the (p,n) reactions on Mn, Fe, and Ni, the elastic scattering of neutrons, and the shielding experiments are discussed. (author)

  19. High-power pulsed lasers

    International Nuclear Information System (INIS)

    Holzrichter, J.F.

    1980-01-01

    The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization

  20. Solution of the multigroup neutron diffusion Eigenvalue problem in slab geometry by modified power method

    Energy Technology Data Exchange (ETDEWEB)

    Zanette, Rodrigo [Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS (Brazil). Programa de Pós-Graduação em Matemática Aplicada; Petersen, Claudio Z.; Tavares, Matheus G., E-mail: rodrigozanette@hotmail.com, E-mail: claudiopetersen@yahoo.com.br, E-mail: matheus.gulartetavares@gmail.com [Universidade Federal de Pelotas (UFPEL), RS (Brazil). Programa de Pós-Graduação em Modelagem Matemática

    2017-07-01

    We describe in this work the application of the modified power method for solve the multigroup neutron diffusion eigenvalue problem in slab geometry considering two-dimensions for nuclear reactor global calculations. It is well known that criticality calculations can often be best approached by solving eigenvalue problems. The criticality in nuclear reactors physics plays a relevant role since establishes the ratio between the numbers of neutrons generated in successive fission reactions. In order to solve the eigenvalue problem, a modified power method is used to obtain the dominant eigenvalue (effective multiplication factor (K{sub eff})) and its corresponding eigenfunction (scalar neutron flux), which is non-negative in every domain, that is, physically relevant. The innovation of this work is solving the neutron diffusion equation in analytical form for each new iteration of the power method. For solve this problem we propose to apply the Finite Fourier Sine Transform on one of the spatial variables obtaining a transformed problem which is resolved by well-established methods for ordinary differential equations. The inverse Fourier transform is used to reconstruct the solution for the original problem. It is known that the power method is an iterative source method in which is updated by the neutron flux expression of previous iteration. Thus, for each new iteration, the neutron flux expression becomes larger and more complex due to analytical solution what makes propose that it be reconstructed through an polynomial interpolation. The methodology is implemented to solve a homogeneous problem and the results are compared with works presents in the literature. (author)

  1. High-pressure cell for simultaneous dielectric and neutron spectroscopy

    Science.gov (United States)

    Sanz, Alejandro; Hansen, Henriette Wase; Jakobsen, Bo; Pedersen, Ib H.; Capaccioli, Simone; Adrjanowicz, Karolina; Paluch, Marian; Gonthier, Julien; Frick, Bernhard; Lelièvre-Berna, Eddy; Peters, Judith; Niss, Kristine

    2018-02-01

    In this article, we report on the design, manufacture, and testing of a high-pressure cell for simultaneous dielectric and neutron spectroscopy. This cell is a unique tool for studying dynamics on different time scales, from kilo- to picoseconds, covering universal features such as the α relaxation and fast vibrations at the same time. The cell, constructed in cylindrical geometry, is made of a high-strength aluminum alloy and operates up to 500 MPa in a temperature range between roughly 2 and 320 K. In order to measure the scattered neutron intensity and the sample capacitance simultaneously, a cylindrical capacitor is positioned within the bore of the high-pressure container. The capacitor consists of two concentric electrodes separated by insulating spacers. The performance of this setup has been successfully verified by collecting simultaneous dielectric and neutron spectroscopy data on dipropylene glycol, using both backscattering and time-of-flight instruments. We have carried out the experiments at different combinations of temperature and pressure in both the supercooled liquid and glassy state.

  2. Development of a high-count-rate neutron detector with position sensitivity and high efficiency

    International Nuclear Information System (INIS)

    Nelson, R.; Sandoval, J.

    1996-01-01

    While the neutron scattering community is bombarded with hints of new technologies that may deliver detectors with high-count-rate capability, high efficiency, gamma-ray insensitivity, and high resolution across large areas, only the time-tested, gas-filled 3 He and scintillation detectors are in widespread use. Future spallation sources with higher fluxes simply must exploit some of the advanced detector schemes that are as yet unproved as production systems. Technologies indicating promise as neutron detectors include pixel arrays of amorphous silicon, silicon microstrips, microstrips with gas, and new scintillation materials. This project sought to study the competing neutron detector technologies and determine which or what combination will lead to a production detector system well suited for use at a high-intensity neutron scattering source

  3. Research results for the applications of high power ion beams

    International Nuclear Information System (INIS)

    Yang Hailiang; Qiu Aici; Sun Jianfeng; He Xiaoping; Tang Junping; Wang Haiyang; Zhang Jiasheng; Xu Ri; Peng Jianchang; Ren Shuqing; Li Peng; Yang Li; Huang Jianjun; Zhang Guoguang; Ouyang Xiaoping; Li Hongyu

    2003-01-01

    The results obtained in the theoretical and experimental studies for the application of high power ion beams in certain areas of nuclear physics and material science are reported. The preliminary experimental results of generating 6-7 MeV quasi-monoenergetic pulsed γ-rays with high power pulsed proton beams striking 19 F target on the Flash II accelerator are presented. By placing the target far enough downstream, the quasi-monoenergetic pulsed γ-rays can be discriminated experimentally from the diode Bremsstrahlung. This article also describes the other applications of high power ion beams and the preliminary experimental and theoretical results in simulation of soft X-ray thermal-mechanical effects, generation of high intense pulsed neutrons, equation of state and shock-wave physics experiments, surface modification and so on

  4. Improving the neutron-to-photon discrimination capability of detectors used for neutron dosimetry in high energy photon beam radiotherapy

    International Nuclear Information System (INIS)

    Irazola, L.; Terrón, J.A.; Bedogni, R; Pola, A.; Lorenzoli, M.; Sánchez-Nieto, B.; Gómez, F.; Sánchez-Doblado, F.

    2016-01-01

    The increasing interest of the medical community to radioinduced second malignancies due to photoneutrons in patients undergoing high-energy radiotherapy, has stimulated in recent years the study of peripheral doses, including the development of some dedicated active detectors. Although these devices are designed to respond to neutrons only, their parasitic photon response is usually not identically zero and anisotropic. The impact of these facts on measurement accuracy can be important, especially in points close to the photon field-edge. A simple method to estimate the photon contribution to detector readings is to cover it with a thermal neutron absorber with reduced secondary photon emission, such as a borated rubber. This technique was applied to the TNRD (Thermal Neutron Rate Detector), recently validated for thermal neutron measurements in high-energy photon radiotherapy. The positive results, together with the accessibility of the method, encourage its application to other detectors and different clinical scenarios. - Highlights: • Neutron-to-photon discrimination of a thermal neutron detector used in radiotherapy. • Photon and anisotropic response study with distance and beam incidence of thermal neutron detector. • Borated rubber for estimating photon contribution in any thermal neutron detector.

  5. Self-powered in-core neutron detector assembly with uniform perturbation characteristics

    International Nuclear Information System (INIS)

    1981-01-01

    An in-core neutron detector assembly consisting of a number of longitudinally extending self-powered detectors is described. The uniform mechanical structures and materials are placed symmetrically at each active detector portion thus ensuring that local perturbation factors are uniform. (U.K.)

  6. Use of FET in automatic scanning of measurements using thermocouples and self-powered neutron detectors

    International Nuclear Information System (INIS)

    Plaige, Yves.

    1977-01-01

    Advantages lying in using FET switches in the relays of multiplexing systems are shown with two examples of application. Their performance as regard fast reliable operation are used in temperature measurement scanning inside nuclear reactors. As for current measurements using self-powered neutron detectors, the weak leakage currents of said switches ( [fr

  7. Fusion blankets for high efficiency power cycles

    International Nuclear Information System (INIS)

    Powell, J.R.; Fillo, J.A.; Horn, F.L.; Lazareth, O.W.; Usher, J.L.

    1980-04-01

    Definitions are given of 10 generic blanket types and the specific blanket chosen to be analyzed in detail from each of the 10 types. Dimensions, compositions, energy depositions and breeding ratios (where applicable) are presented for each of the 10 designs. Ultimately, based largely on neutronics and thermal hyraulics results, breeding an nonbreeding blanket options are selected for further design analysis and integration with a suitable power conversion subsystem

  8. Exploring novel high power density concepts for attractive fusion systems

    Energy Technology Data Exchange (ETDEWEB)

    Abdou, M.A. [California State Univ., Los Angeles, CA (United States). Dept. of Mechanical Engineering; APEX Team

    1999-05-01

    The advanced power extraction study is aimed at exploring innovative concepts for fusion power technology (FPT) that can tremendously enhance the potential of fusion as an attractive and competitive energy source. Specifically, the study is exploring new and `revolutionary` concepts that can provide the capability to efficiently extract heat from systems with high neutron and surface heat loads while satisfying all the FPT functional requirements and maximizing reliability, maintainability, safety, and environmental requirements. The primary criteria for measuring performance of the new concepts are: (1) high power density capability with a peak neutron wall load (NWL) of {proportional_to}10 MW m{sup -2} and surface heat flux of {proportional_to}2 MW m{sup -2}; (2) high power conversion efficiency, {proportional_to}40% net; and (3) clear potential to achieve high availability; specifically low failure rate, large design margin, and short downtime for maintenance. A requirement that MTBF{>=}43 MTTR was derived as a necessary condition to achieve the required first wall/blanket availability, where MTBF is the mean time between failures and MTTR is the mean time to recover. Highlights of innovative and promising new concepts that may satisfy these criteria are provided. (orig.) 40 refs.

  9. High-current negative-ion sources for pulsed spallation neutron sources: LBNL workshop, October 1994

    International Nuclear Information System (INIS)

    Alonso, J.R.

    1995-09-01

    The neutron scattering community has endorsed the need for a high-power (1 to 5 MW) accelerator-driven source of neutrons for materials research. Properly configured, the accelerator could produce very short (sub-microsecond) bursts of cold neutrons, said time structure offering advantages over the continuous flux from a reactor. The recent cancellation of the ANS reactor project has increased the urgency to develop a comprehensive strategy based on the best technological scenarios. Studies to date have built on the experience from ISIS (the 160 kW source in the UK), and call for a high-current (approx. 100 mA peak) H- source-linac combination injecting into one or more accumulator rings in which beam may be further accelerated. The I to 5 GeV proton beam is extracted in a single turn and brought to the target-moderator stations. The high current, high duty-factor, high brightness and high reliability required of the ion source present a very large challenge to the ion source community. The Workshop reported on here, held in Berkeley in October 1994, analyzed in detail the source requirements for proposed accelerator scenarios, the present performance capabilities of different H- source technologies, and identified necessary R ampersand D efforts to bridge the gap

  10. Use of high voltage electron microscope to simulate radiation damage by neutrons

    International Nuclear Information System (INIS)

    Mayer, R.M.

    1976-01-01

    The use of the high voltage electron microscope to simulate radiation damage by neutrons is briefly reviewed. This information is important in explaining how alloying affects void formation during neutron irradiation

  11. Neutronic analyses of the preliminary design of a DCLL blanket for the EUROfusion DEMO power plant

    Energy Technology Data Exchange (ETDEWEB)

    Palermo, Iole, E-mail: iole.palermo@ciemat.es; Fernández, Iván; Rapisarda, David; Ibarra, Angel

    2016-11-01

    Highlights: • We perform neutronic calculations for the preliminary DCLL Blanket design. • We study the tritium breeding capability of the reactor. • We determine the nuclear heating in the main components. • We verify if the shielding of the TF coil is maintained. - Abstract: In the frame of the newly established EUROfusion WPBB Project for the period 2014–2018, four breeding blanket options are being investigated to be used in the fusion power demonstration plant DEMO. CIEMAT is leading the development of the conceptual design of the Dual Coolant Lithium Lead, DCLL, breeding blanket. The primary role of the blanket is of energy extraction, tritium production, and radiation shielding. With this aim the DCLL uses LiPb as primary coolant, tritium breeder and neutron multiplier and Eurofer as structural material. Focusing on the achievement of the fundamental neutronic responses a preliminary blanket model has been designed. Thus detailed 3D neutronic models of the whole blanket modules have been generated, arranged in a specific DCLL segmentation and integrated in the generic DEMO model. The initial design has been studied to demonstrate its viability. Thus, the neutronic behaviour of the blanket and of the shield systems in terms of tritium breeding capabilities, power generation and shielding efficiency has been assessed in this paper. The results demonstrate that the primary nuclear performances are already satisfactory at this preliminary stage of the design, having obtained the tritium self-sufficiency and an adequate shielding.

  12. Engineering safety features for high power experimental reactors

    International Nuclear Information System (INIS)

    Doval, A.; Villarino, E.; Vertullo, A.

    2000-01-01

    In the present analysis we will focus our attention in the way engineering safety features are designed in order to prevent fuel damage in case of abnormal or accidental situations. To prevent fuel damage two main facts must be considered, the shutdown of the reactor and the adequate core cooling capacity, it means that both, neutronic and thermohydraulic aspects must be analysed. Some neutronic safety features are common to all power ranges like negative feedback reactivity coefficients and the required number of control rods containing the proper absorber material to shutdown the reactor. From the thermohydraulic point of view common features are siphon-breaker devices and flap valves for those powers requiring cooling in the forced convection regime. For the high power reactor group, the engineering safety features specially designed for a generic reactor of 20 MW, will be presented here. From the neutronic point of view besides the common features, and to comply with our National Regulatory Authority, a Second Shutdown System was designed as a redundant shutdown system in case the control plates fail. Concerning thermohydraulic aspects besides the pump flywheels and the flap valves providing the natural convection loop, a metallic Chimney and a Chimney Water Injection System were supplied. (author)

  13. High-energy neutron irradiation of superconducting compounds

    International Nuclear Information System (INIS)

    Sweedler, A.R.; Snead, C.L.; Newkirk, L.; Valencia, F.; Geballe, T.H.; Schwall, R.H.; Matthias, B.T.; Corenswit, E.

    1975-01-01

    The effect of high-energy neutron irradiation (E greater than 1 MeV) at ambient reactor temperatures on the superconducting properties of a variety of superconducting compounds is reported. The materials studied include the A-15 compounds Nb 3 Sn, Nb 3 Al, Nb 3 Ga, Nb 3 Ge and V 3 Si, the C-15 Laves phase HfV 2 , the ternary molybdenum sulfide Mo 3 Pb 0 . 5 S 4 and the layered dichalcogenide NbSe 2 . The superconducting transition temperature has been measured for all of the above materials for neutron fluences up to 5 x 10 19 n/cm 2 . The critical current for multifilamentary Nb 3 Sn has also been determined for fields up to 16 T and fluences between 3 x 10 17 n/cm 2 and 1.1 x 10 19 n/cm 2

  14. Upgrade of the compact neutron spectrometer for high flux environments

    Science.gov (United States)

    Osipenko, M.; Bellucci, A.; Ceriale, V.; Corsini, D.; Gariano, G.; Gatti, F.; Girolami, M.; Minutoli, S.; Panza, F.; Pillon, M.; Ripani, M.; Trucchi, D. M.

    2018-03-01

    In this paper new version of the 6Li-based neutron spectrometer for high flux environments is described. The new spectrometer was built with commercial single crystal Chemical Vapour Deposition diamonds of electronic grade. These crystals feature better charge collection as well as higher radiation hardness. New metal contacts approaching ohmic conditions were deposited on the diamonds suppressing build-up of space charge observed in the previous prototypes. New passive preamplification of the signal at detector side was implemented to improve its resolution. This preamplification is based on the RF transformer not sensitive to high neutron flux. The compact mechanical design allowed to reduce detector size to a tube of 1 cm diameter and 13 cm long. The spectrometer was tested in the thermal column of TRIGA reactor and at the DD neutron generator. The test results indicate an energy resolution of 300 keV (FWHM), reduced to 72 keV (RMS) excluding energy loss, and coincidence timing resolution of 160 ps (FWHM). The measured data are in agreement with Geant4 simulations except for larger energy loss tail presumably related to imperfections of metal contacts and glue expansion.

  15. The SPES High Power ISOL production target

    Science.gov (United States)

    Andrighetto, A.; Corradetti, S.; Ballan, M.; Borgna, F.; Manzolaro, M.; Scarpa, D.; Monetti, A.; Rossignoli, M.; Silingardi, R.; Mozzi, A.; Vivian, G.; Boratto, E.; De Ruvo, L.; Sattin, N.; Meneghetti, G.; Oboe, R.; Guerzoni, M.; Margotti, A.; Ferrari, M.; Zenoni, A.; Prete, G.

    2016-11-01

    SPES (Selective Production of Exotic Species) is a facility under construction at INFN-LNL (Istituto Nazionale di Fisica Nucleare - Laboratori Nazionali di Legnaro), aimed to produce intense neutron-rich radioactive ion beams (RIBs). These will be obtained using the ISOL (Isotope Separation On-Line) method, bombarding a uranium carbide target with a proton beam of 40MeV energy and currents up to 200μA. The target configuration was designed to obtain a high number of fissions, up to 1013 per second, low power deposition and fast release of the produced isotopes. The exotic isotopes generated in the target are ionized, mass separated and re-accelerated by the ALPI superconducting LINAC at energies of 10AMeV and higher, for masses in the region of A = 130 amu , with an expected rate on the secondary target up to 109 particles per second. In this work, recent results on the R&D activities regarding the SPES RIB production target-ion source system are reported.

  16. Neutron scattering studies on the high Tc superconductor YBa2Cu306+x

    International Nuclear Information System (INIS)

    Jurgens, M.J.G.M.

    1990-01-01

    The aim of the work described in this thesis is to clarify some of the magnetic aspects of high T c superconductors across the phase diagram as a function of doping and temperature, for which YBa 2 Cu 3 o 6+x has been chosen. Mainly the neutron scattering technique has been employed, which supplies a very powerful tool for this kind of research, for it directly shows the microscopic phenomena of the magnetism involved. First an introduction to the neutron scattering technique is given and a description of the spectrometers employed (ch. 2). The determination of the crystal structure of YBa 2 Cu 3 o 6+x is described, and the single crystals which were used during all the experiments on the magnetic properties as described in this thesis, are characterized (ch. 3). Ch. 4 deals with the phase diagram of the insulating antiferromagnetic phase in YBa 2 Cu 3 o 6+x , as obtained with neutron scattering. The inelastic scattering experiments on the magnetic excitations in this system are presented in ch. 5. In ch. 6 the total susceptibility, measure with a AQUID, is discussed. The local magnetizations, as determined with a polarized neutron scattering technique are the subject of ch. 7. (author). 254 refs.; 77 figs.; 25 tabs

  17. Simulation of a high energy neutron irradiation facility at beamline 11 of the China Spallation Neutron Source

    Energy Technology Data Exchange (ETDEWEB)

    Tairan, Liang [School of Physics and Electronic Information Inner Mongolia University for the Nationalities, Tongliao 028043 (China); Zhiduo, Li [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Wen, Yin, E-mail: wenyin@aphy.iphy.ac.cn [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Institute of Physics, CAS, P.O. Box 603, Beijing 100190 (China); Fei, Shen [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Quanzhi, Yu [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China); Institute of Physics, CAS, P.O. Box 603, Beijing 100190 (China); Tianjiao, Liang [Dongguan Branch, Institute of High Energy Physics, CAS, Beijing 100049 (China)

    2017-07-11

    The China Spallation Neutron Source (CSNS) will accommodate 20 neutron beamlines at its first target station. These beamlines serve different purposes, and beamline 11 is designed to analyze the degraded models and damage mechanisms, such as Single Event Effects in electronic components and devices for aerospace electronic systems. This paper gives a preliminary discussion on the scheme of a high energy neutron irradiation experiment at the beamline 11 shutter based on the Monte Carlo simulation method. The neutron source term is generated by calculating the neutrons scattering into beamline 11 with a model that includes the target-moderator-reflector area. Then, the neutron spectrum at the sample position is obtained. The intensity of neutrons with energy of hundreds of MeV is approximately 1E8 neutron/cm{sup 2}/s, which is useful for experiments. The displacement production rate and gas productions are calculated for common materials such as tungsten, tantalum and SS316. The results indicate that the experiment can provide irradiation dose rate ranges from 1E-5 to 1E-4 dpa per operating year. The residual radioactivity is also calculated for regular maintenance work. These results give the basic reference for the experimental design.

  18. New measurement system for on line in core high-energy neutron flux monitoring in materials testing reactor conditions

    Science.gov (United States)

    Geslot, B.; Vermeeren, L.; Filliatre, P.; Lopez, A. Legrand; Barbot, L.; Jammes, C.; Bréaud, S.; Oriol, L.; Villard, J.-F.

    2011-03-01

    Flux monitoring is of great interest for experimental studies in material testing reactors. Nowadays, only the thermal neutron flux can be monitored on line, e.g., using fission chambers or self-powered neutron detectors. In the framework of the Joint Instrumentation Laboratory between SCK-CEN and CEA, we have developed a fast neutron detector system (FNDS) capable of measuring on line the local high-energy neutron flux in fission reactor core and reflector locations. FNDS is based on fission chambers measurements in Campbelling mode. The system consists of two detectors, one detector being mainly sensitive to fast neutrons and the other one to thermal neutrons. On line data processing uses the CEA depletion code DARWIN in order to disentangle fast and thermal neutrons components, taking into account the isotopic evolution of the fissile deposit. The first results of FNDS experimental test in the BR2 reactor are presented in this paper. Several fission chambers have been irradiated up to a fluence of about 7 × 1020 n/cm2. A good agreement (less than 10% discrepancy) was observed between FNDS fast flux estimation and reference flux measurement.

  19. New measurement system for on line in core high-energy neutron flux monitoring in materials testing reactor conditions

    Energy Technology Data Exchange (ETDEWEB)

    Geslot, B.; Filliatre, P.; Barbot, L.; Jammes, C.; Breaud, S.; Oriol, L.; Villard, J.-F. [CEA, DEN, Cadarache, SPEx/LDCI, F-13108 Saint-Paul-lez-Durance (France); Vermeeren, L. [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Lopez, A. Legrand [CEA, DEN, Saclay, SIREN/LECSI, F-91400 Saclay (France)

    2011-03-15

    Flux monitoring is of great interest for experimental studies in material testing reactors. Nowadays, only the thermal neutron flux can be monitored on line, e.g., using fission chambers or self-powered neutron detectors. In the framework of the Joint Instrumentation Laboratory between SCK-CEN and CEA, we have developed a fast neutron detector system (FNDS) capable of measuring on line the local high-energy neutron flux in fission reactor core and reflector locations. FNDS is based on fission chambers measurements in Campbelling mode. The system consists of two detectors, one detector being mainly sensitive to fast neutrons and the other one to thermal neutrons. On line data processing uses the CEA depletion code DARWIN in order to disentangle fast and thermal neutrons components, taking into account the isotopic evolution of the fissile deposit. The first results of FNDS experimental test in the BR2 reactor are presented in this paper. Several fission chambers have been irradiated up to a fluence of about 7 x 10{sup 20} n/cm{sup 2}. A good agreement (less than 10% discrepancy) was observed between FNDS fast flux estimation and reference flux measurement.

  20. New measurement system for on line in core high-energy neutron flux monitoring in materials testing reactor conditions

    International Nuclear Information System (INIS)

    Geslot, B.; Filliatre, P.; Barbot, L.; Jammes, C.; Breaud, S.; Oriol, L.; Villard, J.-F.; Vermeeren, L.; Lopez, A. Legrand

    2011-01-01

    Flux monitoring is of great interest for experimental studies in material testing reactors. Nowadays, only the thermal neutron flux can be monitored on line, e.g., using fission chambers or self-powered neutron detectors. In the framework of the Joint Instrumentation Laboratory between SCK-CEN and CEA, we have developed a fast neutron detector system (FNDS) capable of measuring on line the local high-energy neutron flux in fission reactor core and reflector locations. FNDS is based on fission chambers measurements in Campbelling mode. The system consists of two detectors, one detector being mainly sensitive to fast neutrons and the other one to thermal neutrons. On line data processing uses the CEA depletion code DARWIN in order to disentangle fast and thermal neutrons components, taking into account the isotopic evolution of the fissile deposit. The first results of FNDS experimental test in the BR2 reactor are presented in this paper. Several fission chambers have been irradiated up to a fluence of about 7 x 10 20 n/cm 2 . A good agreement (less than 10% discrepancy) was observed between FNDS fast flux estimation and reference flux measurement.

  1. High pressure gas spheres for neutron and photon experiments

    Science.gov (United States)

    Rupp, G.; Petrich, D.; Käppeler, F.; Kaltenbaek, J.; Leugers, B.; Reifarth, R.

    2009-09-01

    High pressure gas spheres have been designed and successfully used in several nuclear physics experiments on noble gases. The pros and cons of this solution are the simple design and the high reliability versus the fact that the density is limited to 40-60% of liquid or solid gas samples. Originally produced for neutron capture studies at keV energies, the comparably small mass of the gas spheres were an important advantage, which turned out to be of relevance for other applications as well. The construction, performance, and operation of the spheres are described and examples for their use are presented.

  2. Cation disorder in high-dose, neutron-irradiated spinel

    International Nuclear Information System (INIS)

    Sickafus, K.E.; Larson, A.C.; Yu, N.; Nastasi, M.; Hollenberg, G.W.; Garner, F.A.; Bradt, R.C.

    1994-08-01

    The objective of this effort is to determine whether MgAl 2 O 4 spinel is a suitable ceramic for fusion applications. Here, the crystal structures of MgAl 2 O 4 spinel single crystals irradiated to high neutron fluences [>5·10 26 n/m 2 (E n > 0.1 MeV)] were examined by neutron diffraction. Crystal structure refinement of the highest dose sample indicated that the average scattering strength of the tetrahedral crystal sites decreased by ∼ 20% while increasing by ∼ 8% on octahedral sites. Since the neutron scattering length for Mg is considerably larger than for Al, this results is consistent with site exchange between Mg 2+ ions on tetrahedral sites and Al 3+ ions on octahedral sites. Least-squares refinements also indicated that, in all irradiated samples, at least 35% of Mg 2+ and Al 3+ ions in the crystal experienced disordering replacements. This retained dpa on the cation sublattices is the largest retained damage ever measured in an irradiated spinel material

  3. Formation of austenite in high Cr ferritic/martensitic steels by high fluence neutron irradiation

    Science.gov (United States)

    Lu, Z.; Faulkner, R. G.; Morgan, T. S.

    2008-12-01

    High Cr ferritic/martensitic steels are leading candidates for structural components of future fusion reactors and new generation fission reactors due to their excellent swelling resistance and thermal properties. A commercial grade 12%CrMoVNb ferritic/martensitic stainless steel in the form of parent plate and off-normal weld materials was fast neutron irradiated up to 33 dpa (1.1 × 10 -6 dpa/s) at 400 °C and 28 dpa (1.7 × 10 -6 dpa/s) at 465 °C, respectively. TEM investigation shows that the fully martensitic weld metal transformed to a duplex austenite/ferrite structure due to high fluence neutron irradiation, the austenite was heavily voided (˜15 vol.%) and the ferrite was relatively void-free; whilst no austenite phases were detected in plate steel. Thermodynamic and phase equilibria software MTDATA has been employed for the first time to investigate neutron irradiation-induced phase transformations. The neutron irradiation effect is introduced by adding additional Gibbs free energy into the system. This additional energy is produced by high energy neutron irradiation and can be estimated from the increased dislocation loop density caused by irradiation. Modelling results show that neutron irradiation reduces the ferrite/austenite transformation temperature, especially for high Ni weld metal. The calculated results exhibit good agreement with experimental observation.

  4. Hot nuclei studied with high efficiency neutron detectors

    International Nuclear Information System (INIS)

    Galin, J.

    1990-01-01

    We have shown the invaluable benefit that a high efficiency 4π neutron detector can bring to the study of reaction mechanisms following collisions of heavy nuclei at intermediate energy. Analysis requires Monte-Carlo simulations for comparison between experimental data and any emission model. In systematic measurements with projectiles of velocity corresponding to energies between 27 and 77 MeV/u, where both the influence of beam velocity and mass have been investigated separately, it has been shown that the projectile-target mass asymmetry, much more than velocity, has a decisive influence on energy dissipation. The closer the projectile mass to the target mass, the more energy is dissipated per unit mass of the considered projectile plus target system. The latter presents all the characteristics of a thermalized system, evaporating a copious number of light particles: up to about 40 neutrons (after efficiency correction) and 11 light charged particles in the most dissipative collisions between Kr+Au, and 90 neutrons for Pb+U with a yet unknown number of l.c.p. In the Kr experiment, these particles are isotropically emitted in the frame of a fused system, excited with 1.2 GeV. Moreover, l.c.p. exhibit Maxwellian energy distributions as in any standard evaporation process. We are now eager to better characterize the properties of the Pb+Au (U) systems for which about 1/3 of the neutrons are freed in a rather large fraction of all collisions. The thermalized energy should then approach very closely the total binding energy of the two interacting nuclei

  5. High pressure apparatus for neutron scattering at low temperature

    International Nuclear Information System (INIS)

    Munakata, Koji; Uwatoko, Yoshiya; Aso, Naofumi

    2010-01-01

    Effects of pressure on the physical properties are very important for understanding highly correlated electron systems, in which pressure-induced attractive phenomena such as superconductivity and magnetically ordered non-Fermi liquid have been observed. Up to now, many scientists have developed a lot of high pressure apparatus for each purpose. The characteristic features of various materials and pressure transmitting media for use of high pressure apparatus are reported. Then, two kinds of clamp type high-pressure cell designed for low-temperature neutron diffraction measurements are shown; one is a piston cylinder type high-pressure cell which can be attached to the dilution refrigerator, and the other one is a newly-developed cubic anvil type high-pressure cell which can generate pressure above 7GPa. We also introduce the results of magnetic neutron scattering under pressure on a pressure-induced superconducting ferromagnet UGe 2 in use of the piston cylinder type clamp cell, and those on an iron arsenide superconductor SrFe 2 As 2 in use of the cubic anvil type clamp cell. (author)

  6. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1993-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  7. Neutron dosimetry; Dosimetria de neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Fratin, Luciano

    1994-12-31

    A neutron irradiation facility was designed and built in order to establish a procedure for calibrating neutron monitors and dosemeters. A 185 GBq {sup 241} Am Be source of known is used as a reference source. The irradiation facility using this source in the air provides neutron dose rates between 9 nSv s{sup -1} and 0,5 {sup {mu}}Sv s{sup -1}. A calibrated 50 nSv s{sup -1} thermal neutron field is obtained by using a specially designed paraffin block in conjunction with the {sup 241} Am Be source. A Bonner multisphere spectrometer was calibrated, using a procedure based on three methods proposed by international standards. The unfold {sup 241} Am Be neutron spectrum was determined from the Bonner spheres data and resulted in a good agreement with expected values for fluence rate, dose rate and mean energy. A dosimetric system based on the electrochemical etching of CR-39 was developed for personal dosimetry. The dosemeter badge using a (n,{alpha}) converter, the etching chamber and high frequency power supply were designed and built specially for this project. The electrochemical etching (ECE) parameters used were: a 6N KOH solution, 59 deg C, 20 kV{sub pp} cm{sup -1}, 2,0 kHz, 3 hours of ECE for thermal and intermediate neutrons and 6 hours for fast neutrons. The calibration factors for thermal, intermediate and fast neutrons were determined for this personal dosemeter. The sensitivities determined for the developed dosimetric system were (1,46{+-} 0,09) 10{sup 4} tracks cm{sup -2} mSv{sup -1} for thermal neutrons, (9{+-}3) 10{sup 2} tracks cm{sup -2} mSV{sup -1} for intermediate neutrons and (26{+-}4) tracks cm{sup -2} mSv{sup -1} for fast neutrons. The lower and upper limits of detection were respectively 0,002 mSv and 0,6 mSv for thermal neutrons, 0,04 mSv and 8 mSv for intermediate neutrons and 1 mSv and 12 mSv for fast neutrons. In view of the 1990`s ICRP recommendations, it is possible to conclude that the personal dosemeter described in this work is

  8. Development of measuring system with self-powered neutron detectors for the LR-0 reactor

    International Nuclear Information System (INIS)

    Erben, O.; Horinek, K.; Szasz, Z.

    1989-01-01

    A measuring channel with self-powered detectors was developed for measuring neutron fluxs density in the reactor core. The measuring channel consists of a measuring probe with standard self-powered detectors of Soviet make, a signal pathway, a current/voltage converter and a measuring and recording unit. Neutron flux density in the LR-0 reactor core reaches a maximum of 10 13 m -2 s -1 . Experiments using the channel were carried out both in steady-state operation and after emergency shutdown of the reactor, this from power levels of 2,096 W and 1,830 W. The results of the experiments are tabulated and briefly analyzed. (Z.M.). 4 figs., 3 tabs., 5 refs

  9. Self powered neutron detectors as in-core detectors for Sodium-cooled Fast Reactors

    Science.gov (United States)

    Verma, V.; Barbot, L.; Filliatre, P.; Hellesen, C.; Jammes, C.; Svärd, S. Jacobsson

    2017-07-01

    Neutron flux monitoring system forms an integral part of the design of a Generation IV sodium cooled fast reactor. Diverse possibilities of detector system installation must be studied for various locations in the reactor vessel in order to detect any perturbations in the core. Results from a previous paper indicated that it is possible to detect changes in neutron source distribution initiated by an inadvertent withdrawal of outer control rod with in-vessel fission chambers located azimuthally around the core. It is, however, not possible to follow inner control rod withdrawal and precisely know the location of the perturbation in the core. Hence the use of complimentary in-core detectors coupled with the peripheral fission chambers is proposed to enable robust core monitoring across the radial direction. In this paper, we assess the feasibility of using self-powered neutron detectors (SPNDs) as in-core detectors in fast reactors for detecting local changes in the power distribution when the reactor is operated at nominal power. We study the neutron and gamma contributions to the total output current of the detector modelled with Platinum as the emitter material. It is shown that this SPND placed in an SFR-like environment would give a sufficiently measurable prompt neutron induced current of the order of 600 nA/m. The corresponding induced current in the connecting cable is two orders of magnitude lower and can be neglected. This means that the SPND can follow in-core power fluctuations. This validates the operability of an SPND in an SFR-like environment.

  10. High-efficiency transmision neutron polarizer for high-resolution double crystal diffractometer

    International Nuclear Information System (INIS)

    Ioffe, A.; Krist, T.; Mezei, F.; Gordeev, G.; Ibrayev, B.

    1997-01-01

    An efficient transmission geometry neutron polarizer for the high-resolution double crystal diffractometer at HMI (λ=4.8 A) is described. A polarization of about 94% was achieved and the polarized neutron beam intensity amounts to 40% of the nonpolarized beam intensity. This opens up wide possibilities for the study of magnetic small-angle scattering for extremely small momentum transfer (Q∝10 -5 A -1 ). (orig.)

  11. Absolute on-line in-pile measurement of neutron fluxes using self-powered neutron detectors: Monte Carlo sensitivity calculations

    Energy Technology Data Exchange (ETDEWEB)

    Vermeeren, L. [SCK/CEN, B-2400 Mol (Belgium)

    2001-07-01

    Self-powered neutron detectors (SPND) are well suited to monitor continuously the neutronic operating conditions of driver fuel of research reactors and to follow its burnup evolution. This is of particular importance when advanced or new MTR fuel designs need to be qualified. We have developed a detailed MCNP-4B based Monte Carlo approach for the calculation of neutron sensitivities of SPNDs. Results for the neutron sensitivity of a Rh SPND are in excellent agreement with experimental data recently obtained at the BR2 research reactor. A critical comparison of the Monte Carlo results with results from standard analytical methods reveals an important deficiency of the analytical methods in the description of the electron transport efficiency. Our calculation method allows a reliable on-line determination of the absolute in-pile neutron flux. (author)

  12. Absolute on-line in-pile measurement of neutron fluxes using self-powered neutron detectors: Monte Carlo sensitivity calculations

    International Nuclear Information System (INIS)

    Vermeeren, L.

    2001-01-01

    Self-powered neutron detectors (SPND) are well suited to monitor continuously the neutronic operating conditions of driver fuel of research reactors and to follow its burnup evolution. This is of particular importance when advanced or new MTR fuel designs need to be qualified. We have developed a detailed MCNP-4B based Monte Carlo approach for the calculation of neutron sensitivities of SPNDs. Results for the neutron sensitivity of a Rh SPND are in excellent agreement with experimental data recently obtained at the BR2 research reactor. A critical comparison of the Monte Carlo results with results from standard analytical methods reveals an important deficiency of the analytical methods in the description of the electron transport efficiency. Our calculation method allows a reliable on-line determination of the absolute in-pile neutron flux. (author)

  13. Neutron flux measurement and thermal power calibration of the IAN-R1 TRIGA reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sarta Fuentes, Jose A.; Castiblanco Bohorquez, Luis A

    2008-10-29

    The IAN-R1 TRIGA reactor in Colombia was initially fueled with MTR-HEU enriched to 93% U-235, operated since 1965 at 10 kW, and was upgraded to 30 kW in 1980. General Atomics achieved in 1997 the conversion of HEU fuel to LEU fuel TRIGA type, and upgraded the reactor power to 100 kW. Since the IAN-R1 TRIGA reactor was in an extended shutdown during seven years, it was necessary to repeat some results of the commissioning test conducted in 1997. The thermal power calibration was carried out using the calorimetric method. The reactor was operated approximately at 20 kW during 3.5 hours, with manual power corrections since the automatic control system failed and with the forced refrigeration off. During the calorimetric experiment, the pool temperature was measured with a RTD which is installed near to the core. The dates were collected in intervals of 30 minutes. For establishing thermal power reactor, the water temperature versus the running were registered. For a calculated tank volume of 16 m{sup 3}, the tank constant calculated for the IAN-R1 TRIGA reactor is 0.0539 C/kW-hr. The reactor power determined was 19 kW. The core configuration is a rectangular grid plate that holds a combination of 4-rod and 3-rod clusters. The core contains 50 fuel rods with LEU fuel TRIGA (UZr H1.6) type enriched to 19.7%. The radial reflector consists of twenty graphite elements six of which are used for isotope production. The top an bottom reflectors are the cylindrical graphite end reflectors which are installed above and below of the active fuel section in each fuel rod. The spatial dependence of thermal neutron flux was measured axially in the 3-rod clusters 4C, 3D, 5E and in the 4F graphite element. The spatial distribution of the thermal neutron was determined using a self-powered detector and the absolute value of thermal neutron flux was determined by a gold activation detector. The (n, b- ) reaction is applied to determine the relative spatial distribution of thermal

  14. Performance of self-powered neutron detectors in pressurized water reactors

    International Nuclear Information System (INIS)

    Warren, H.D.; Bozarch, D.P.

    1977-01-01

    A typical Babcock and Wilcox pressurized water reactor (PWR) contains 364 rhodium self-powered neutron detectors (SPNDs) and 52 background detectors. The detectors are inserted into the reactor core in 52 dry, multidetector assemblies. Each assembly contains seven SPNDs and one background detector. By mid-1977, eight B and W PWRs, each fitted with SPNDs, were in operation. Many of the SPNDs have operated successfully for more than four years. This paper describes the operational performance of the SPNDs and special tests conducted to improve that performance. Topics included are (1) insulation performance versus neutron dose to the SPND, (2) background signals in the leadwire region of the SPND, and (3) depletion of the SPND emitter versus absorbed neutron dose

  15. Optics assembly for high power laser tools

    Science.gov (United States)

    Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

    2016-06-07

    There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

  16. A Permanent-Magnet Microwave Ion Source for a Compact High-Yield Neutron Generator

    International Nuclear Information System (INIS)

    Waldmann, Ole; Ludewigt, Bernhard

    2010-01-01

    We present recent work on the development of a microwave ion source that will be used in a high-yield compact neutron generator for active interrogation applications. The sealed tube generator will be capable of producing high neutron yields, 5 · 10 11 n/s for D-T and ∼ 1 · 10 10 n/s for D-D reactions, while remaining transportable. We constructed a microwave ion source (2.45 GHz) with permanent magnets to provide the magnetic field strength of 87.5 mT necessary for satisfying the electron cyclotron resonance (ECR) condition. Microwave ion sources can produce high extracted beam currents at the low gas pressures required for sealed tube operation and at lower power levels than previously used RF-driven ion sources. A 100 mA deuterium/tritium beam will be extracted through a large slit (60 · 6 mm 2 ) to spread the beam power over a larger target area. This paper describes the design of the permanent-magnet microwave ion source and discusses the impact of the magnetic field design on the source performance. The required equivalent proton beam current density of 40 mA/cm 2 was extracted at a moderate microwave power of 400 W with an optimized magnetic field.

  17. Calibration of ITER Instant Power Neutron Monitors: Recommended Scenario of Experiments at the Reactor

    Science.gov (United States)

    Borisov, A. A.; Deryabina, N. A.; Markovskij, D. V.

    2017-12-01

    Instant power is a key parameter of the ITER. Its monitoring with an accuracy of a few percent is an urgent and challenging aspect of neutron diagnostics. In a series of works published in Problems of Atomic Science and Technology, Series: Thermonuclear Fusion under a common title, the step-by-step neutronics analysis was given to substantiate a calibration technique for the DT and DD modes of the ITER. A Gauss quadrature scheme, optimal for processing "expensive" experiments, is used for numerical integration of 235U and 238U detector responses to the point sources of 14-MeV neutrons. This approach allows controlling the integration accuracy in relation to the number of coordinate mesh points and thus minimizing the number of irradiations at the given uncertainty of the full monitor response. In the previous works, responses of the divertor and blanket monitors to the isotropic point sources of DT and DD neutrons in the plasma profile and to the models of real sources were calculated within the ITER model using the MCNP code. The neutronics analyses have allowed formulating the basic principles of calibration that are optimal for having the maximum accuracy at the minimum duration of in situ experiments at the reactor. In this work, scenarios of the preliminary and basic experimental ITER runs are suggested on the basis of those principles. It is proposed to calibrate the monitors only with DT neutrons and use correction factors to the DT mode calibration for the DD mode. It is reasonable to perform full calibration only with 235U chambers and calibrate 238U chambers by responses of the 235U chambers during reactor operation (cross-calibration). The divertor monitor can be calibrated using both direct measurement of responses at the Gauss positions of a point source and simplified techniques based on the concepts of equivalent ring sources and inverse response distributions, which will considerably reduce the amount of measurements. It is shown that the monitor

  18. Evaluation of neutron flux density and power density with SPN-detectors and micro calorimeters

    International Nuclear Information System (INIS)

    Gehre, G.; Rindelhardt, U.; Seidenkranz, T.; Hogel, J.; Jirousek, V.; Vazek, J.

    1983-02-01

    During investigations with a special equipped fuel assembly in the Rheinsberg nuclear power station the neutron flux and the power density were evaluated from measurements with SPN-detectors and micro calorimeters. The reliability of both detector types, their measurement accuracy under different physical conditions and the usefulness of the developed calculation models are discussed in detail. The thermal flux and the power density evaluated with SPND's agree well with theoretical results. The values obtained through micro calorimeter measurements are systematic lower by about 18%. This deviation is probably a result of differences in the used calculation models. (author)

  19. The Prospect of Neutron Scattering in The 21st Century : A Powerful Tool For Materials Research

    International Nuclear Information System (INIS)

    E-Kartini

    2007-01-01

    Over the last 60 years research reactors (RRs) have played an important role in technological and socio-economical development of mankind, such as radioisotope production for medicine, industry, research and education. Neutron scattering has been widely used for research and development in materials science. The prospect of neutron scattering as a powerful tool for materials research is increasing in the 21 st century. This can be seen from the investment of several new neutron sources all over the world such as the Spallation Neutron Source (SNS) in USA, the Japan Proton Accelerator Complex (JPARC) in Japan, the new OPAL Reactor in Australia, and some upgrading to the existing sources at ISIS, Rutherford Appleton Laboratory, UK; Institute of Laue Langevin (ILL) in Grenoble, France and Berlin Reactor, Germany. Developing countries with moderate flux research reactor have also been involved in this technique, such as India, Malaysia and Indonesia The Siwabessy Multipurpose Reactor in Serpong, Indonesia that also produces thermal neutron has contributed to the research and development in the Asia Pacific Region. However,the international joint research among those countries plays an important role on optimizing the results. (author)

  20. The Prospect of Neutron Scattering In the 21st Century: A Powerful Tool for Materials Research

    Directory of Open Access Journals (Sweden)

    E. Kartini

    2007-07-01

    Full Text Available Over the last 60 years research reactors (RRs have played an important role in technological and socio-economical development of mankind, such as radioisotope production for medicine, industry, research and education. Neutron scattering has been widely used for research and development in materials science. The prospect of neutron scattering as a powerful tool for materials research is increasing in the 21st century. This can be seen from the investment of several new neutron sources all over the world such as the Spallation Neutron Source (SNS in USA, the Japan Proton Accelerator Complex (JPARC in Japan, the new OPAL Reactor in Australia, and some upgrading to the existing sources at ISIS, Rutherford Appleton Laboratory, UK; Institute of Laue Langevin (ILL in Grenoble, France and Berlin Reactor, Germany. Developing countries with moderate flux research reactor have also been involved in this technique, such as India, Malaysia and Indonesia. The Siwabessy Multipurpose Reactor in Serpong, Indonesia that also produces thermal neutron has contributed to the research and development in the Asia Pacific Region. However, the international joint research among those countries plays an important role on optimizing the results.

  1. Rhodium self-powered detector for monitoring neutron fluence, energy production, and isotopic composition of fuel

    International Nuclear Information System (INIS)

    Sokolov, A.P.; Pochivalin, G.P.; Shipovskikh, Yu.M.; Garusov, Yu.V.; Chernikov, O.G.; Shevchenko, V.G.

    1993-01-01

    The use of self-powered detectors (SPDs) with a rhodium emitter customarily involves monitoring of neutron fields in the core of a nuclear reactor. Since current in an SPD is generated primarily because of the neutron flux, which is responsible for the dynamics of particular nuclear transformations, including fission reactions of heavy isotopes, the detector signal can be attributed unambiguously to energy release at the location of the detector. Computation modeling performed with the KOMDPS package of programs of the current formation in a rhodium SPD along with the neutron-physical processes that occur in the reactor core makes it possible to take account of the effect of the principal factors characterizing the operating conditions and the design features of the fuel channel and the detector, reveal quantitative relations between the generated signal and individual physical parameters, and determine the metrological parameters of the detector. The formation and transport of changed particles in the sensitive part of the SPC is calculated by the Monte Carlo method. The emitter activation, neutron transport, and dynamics of the isotopic composition in the fuel channel containing the SPD are determined by solving the kinetic equation in the multigroup representation of the neutron spectrum, using the discrete ordinate method. In this work the authors consider the operation of a rhodium SPD in a bundle of 49 fuel channels of the RBMK-1000 reactor with a fuel enrichment of 2.4% from the time it is inserted into a fresh channel

  2. Neutron and gamma sensitivities of self-powered detectors: Monte Carlo modelling

    Energy Technology Data Exchange (ETDEWEB)

    Vermeeren, Ludo [SCK-CEN, Nuclear Research Centre, Boeretang 200, B-2400 Mol, (Belgium)

    2015-07-01

    This paper deals with the development of a detailed Monte Carlo approach for the calculation of the absolute neutron sensitivity of SPNDs, which makes use of the MCNP code. We will explain the calculation approach, including the activation and beta emission steps, the gamma-electron interactions, the charge deposition in the various detector parts and the effect of the space charge field in the insulator. The model can also be applied for the calculation of the gamma sensitivity of self-powered detectors and for the radiation-induced currents in signal cables. The model yields detailed information on the various contributions to the sensor currents, with distinct response times. Results for the neutron sensitivity of various types of SPNDs are in excellent agreement with experimental data obtained at the BR2 research reactor. For typical neutron to gamma flux ratios, the calculated gamma induced SPND currents are significantly lower than the neutron induced currents. The gamma sensitivity depends very strongly upon the immediate detector surroundings and on the gamma spectrum. Our calculation method opens the way to a reliable on-line determination of the absolute in-pile thermal neutron flux. (authors)

  3. Thin film CdTe based neutron detectors with high thermal neutron efficiency and gamma rejection for security applications

    Energy Technology Data Exchange (ETDEWEB)

    Smith, L.; Murphy, J.W. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Kim, J. [Korean Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of); Rozhdestvenskyy, S.; Mejia, I. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Park, H. [Korean Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of); Allee, D.R. [Flexible Display Center, Arizona State University, Phoenix, AZ 85284 (United States); Quevedo-Lopez, M. [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Gnade, B., E-mail: beg031000@utdallas.edu [Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States)

    2016-12-01

    Solid-state neutron detectors offer an alternative to {sup 3}He based detectors, but suffer from limited neutron efficiencies that make their use in security applications impractical. Solid-state neutron detectors based on single crystal silicon also have relatively high gamma-ray efficiencies that lead to false positives. Thin film polycrystalline CdTe based detectors require less complex processing with significantly lower gamma-ray efficiencies. Advanced geometries can also be implemented to achieve high thermal neutron efficiencies competitive with silicon based technology. This study evaluates these strategies by simulation and experimentation and demonstrates an approach to achieve >10% intrinsic efficiency with <10{sup −6} gamma-ray efficiency.

  4. Development of high flux thermal neutron generator for neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vainionpaa, Jaakko H., E-mail: hannes@adelphitech.com [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Chen, Allan X.; Piestrup, Melvin A.; Gary, Charles K. [Adelphi Technology, 2003 E Bayshore Rd, Redwood City, CA 94063 (United States); Jones, Glenn [G& J Jones Enterprice, 7486 Brighton Ct, Dublin, CA 94568 (United States); Pantell, Richard H. [Department of Electrical Engineering, Stanford University, Stanford, CA (United States)

    2015-05-01

    The new model DD110MB neutron generator from Adelphi Technology produces thermal (<0.5 eV) neutron flux that is normally achieved in a nuclear reactor or larger accelerator based systems. Thermal neutron fluxes of 3–5 · 10{sup 7} n/cm{sup 2}/s are measured. This flux is achieved using four ion beams arranged concentrically around a target chamber containing a compact moderator with a central sample cylinder. Fast neutron yield of ∼2 · 10{sup 10} n/s is created at the titanium surface of the target chamber. The thickness and material of the moderator is selected to maximize the thermal neutron flux at the center. The 2.5 MeV neutrons are quickly thermalized to energies below 0.5 eV and concentrated at the sample cylinder. The maximum flux of thermal neutrons at the target is achieved when approximately half of the neutrons at the sample area are thermalized. In this paper we present simulation results used to characterize performance of the neutron generator. The neutron flux can be used for neutron activation analysis (NAA) prompt gamma neutron activation analysis (PGNAA) for determining the concentrations of elements in many materials. Another envisioned use of the generator is production of radioactive isotopes. DD110MB is small enough for modest-sized laboratories and universities. Compared to nuclear reactors the DD110MB produces comparable thermal flux but provides reduced administrative and safety requirements and it can be run in pulsed mode, which is beneficial in many neutron activation techniques.

  5. Neutron activation analysis of high-purity zinc

    International Nuclear Information System (INIS)

    Khodzhamberdyeva, A.A.; Usmanova, M.M.; Gil'bert, Eh.N.; Ivanov, I.M.; Yankovskaya, T.A.; Kholyavko, E.P.

    1987-01-01

    The methods of neutron activation analysis of high-purity zinc with preliminary separation of the zinc base using extraction by trialkylbenzylammonium rhodanide in carbon tetrachloride from 0.5-2.0 M nitric acid solutions is developed. Only rhenium is quantitatively extracted together with zinc. Gold, iridium and molybdenum are extracted to 50-60%, and selenium - to 20%. The Na, K, La, Cr, Sc, Co, Cs, Rb, Fe, Zr, Sn, Te, As, Cd, Hf, W, Sb, Sm impurities remain in the aqueous phase. The methods permits to determine the impurities above with detection limits from 1x10 -6 to 4x10 -11 g

  6. High-level neutron coincidence counter maintenance manual

    International Nuclear Information System (INIS)

    Swansen, J.; Collinsworth, P.

    1983-05-01

    High-level neutron coincidence counter operational (field) calibration and usage is well known. This manual makes explicit basic (shop) check-out, calibration, and testing of new units and is a guide for repair of failed in-service units. Operational criteria for the major electronic functions are detailed, as are adjustments and calibration procedures, and recurrent mechanical/electromechanical problems are addressed. Some system tests are included for quality assurance. Data on nonstandard large-scale integrated (circuit) components and a schematic set are also included

  7. High-level neutron coincidence counter maintenance manual

    Energy Technology Data Exchange (ETDEWEB)

    Swansen, J.; Collinsworth, P.

    1983-05-01

    High-level neutron coincidence counter operational (field) calibration and usage is well known. This manual makes explicit basic (shop) check-out, calibration, and testing of new units and is a guide for repair of failed in-service units. Operational criteria for the major electronic functions are detailed, as are adjustments and calibration procedures, and recurrent mechanical/electromechanical problems are addressed. Some system tests are included for quality assurance. Data on nonstandard large-scale integrated (circuit) components and a schematic set are also included.

  8. high power facto high power factor high power factor hybrid rectifier

    African Journals Online (AJOL)

    eobe

    increase in the number of electrical loads that some kind of ... components in the AC power system. Thus, suppl ... al output power; assuring reliability in ... distribution systems. This can be ...... Thesis- Califonia Institute of Technology, Capitulo.

  9. Cadmium-emitter self-powered thermal neutron detector performance characterization & reactor power tracking capability experiments performed in ZED-2

    Energy Technology Data Exchange (ETDEWEB)

    LaFontaine, M.W., E-mail: physics@execulink.com [LaFontaine Consulting, Kitchener, Ontario (Canada); Zeller, M.B. [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada); Nielsen, K. [Royal Military College of Canada, SLOWPOKE-2 Reactor, Kingston, Ontario (Canada)

    2014-07-01

    Cadmium-emitter self-powered thermal neutron flux detectors (SPDs), are typically used for flux monitoring and control applications in low temperature, test reactors such as the SLOWPOKE-2. A collaborative program between Atomic Energy of Canada, academia (Royal Military College of Canada (RMCC)) and industry (LaFontaine Consulting) was initiated to characterize the incore performance of a typical Cd-emitter SPD; and to obtain a definitive measure of the capability of the detector to track changes in reactor power in real time. Prior to starting the experiment proper, Chalk River Laboratories' ZED-2 was operated at low power (5 watts nominal) to verify the predicted moderator critical height. Test measurements were then performed with the vertical center of the SPD emitter positioned at the vertical mid-plane of the ZED-2 reactor core. Measurements were taken with the SPD located at lattice position L0 (near center), and repeated at lattice position P0 (in D{sub 2}O reflector). An ionization chamber (part of the ZED-2 control instrumentation) monitored reactor power at a position located on the south side of the outside wall of the reactor's calandria. These experiments facilitated measurement of the absolute thermal neutron sensitivity of the subject Cd-emitter SPD, and validated the power tracking capability of said SPD. Procedural details of the experiments, data, calculations and associated graphs, are presented and discussed. (author)

  10. Using anisotropies in prompt fission neutron coincidences to assess the neutron multiplication of highly multiplying subcritical plutonium assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, J.M., E-mail: jonathan_mueller@ncsu.edu; Mattingly, J.

    2016-07-21

    There is a significant and well-known anisotropy between the prompt neutrons emitted from a single fission event; these neutrons are most likely to be observed at angles near 0° or 180° relative to each other. However, the propagation of this anisotropy through different generations of a fission chain reaction has not been previously studied. We have measured this anisotropy in neutron–neutron coincidences from a subcritical highly-multiplying assembly of plutonium metal. The assembly was a 4.5 kg α-phase plutonium metal sphere composed of 94% {sup 239}Pu and 6% {sup 240}Pu by mass. Data were collected using two EJ-309 liquid scintillators and two EJ-299 plastic scintillators. The angular distribution of neutron–neutron coincidences was measured at 90° and 180° and found to be largely isotropic. Simulations were performed using MCNPX-PoliMi of similar plutonium metal spheres of varying sizes and a correlation between the neutron multiplication of the assembly and the anisotropy of neutron–neutron coincidences was observed. In principle, this correlation could be used to assess the neutron multiplication of an unknown assembly.

  11. Robust filtering for dynamic compensation of self-powered neutron detectors

    International Nuclear Information System (INIS)

    Peng, Xingjie; Li, Qing; Zhao, Wenbo; Gong, Helin; Wang, Kan

    2014-01-01

    Highlights: • Three dynamic compensation methods based on robust filtering theory are proposed. • Filter design problems are converted into linear matrix inequality problems. • Rhodium and Vanadium self-powered neutron detectors are used to validate the use of these three dynamic compensation methods. • The numerical simulation results show that all three methods can provide a reasonable balance between response speed and noise suppression. - Abstract: Self-powered neutron detectors (SPNDs), which are widely used in nuclear reactors to obtain core neutron flux distribution, are accurate at steady state but respond slowly to changes in neutron flux. Dynamic compensation methods are required to improve the response speed of the SPNDs and make it possible to apply the SPNDs for core monitoring and surveillance. In this paper, three digital dynamic compensation methods are proposed. All the three methods are based on the convex optimization framework using linear matrix inequalities (LMIs). The simulation results show that all three methods can provide a reasonable balance between response speed and noise suppression

  12. Self-Powered Neutron Detector Calibration Using a Large Vertical Irradiation Hole of HANARO

    Directory of Open Access Journals (Sweden)

    Kim Myong-Seop

    2018-01-01

    Full Text Available A calibration technology of the self-powered neutron detectors (SPNDs using a large vertical irradiation hole of HANARO is developed. The 40 Rh-SPNDs are installed on the polycarbonate plastic support, and the gold wires with the same length as the effective length of the rhodium emitter of the SPND are also installed to measure the neutron flux on the SPND. They are irradiated at a low reactor power, and the SPND current is measured using the pico-ammeter. The external gamma-rays which affect the SPND current response are analyzed using the Monte Carlo simulation for various irradiation conditions in HANARO. It is confirmed that the effect of the external gamma-rays to the SPND current is dependent on the reactor characteristics, and that it is affected by materials around the detector. The current signals due to the external gamma-rays can be either positive or negative, in that the net flow of the current may be either in the same or the opposite direction as the neutron-induced current by the rhodium emitter. From the above procedure, the effective calibration methodology of multiple SPNDs using the large hole of HANARO is developed. It could be useful for the calibration experiment of the neutron detectors in the research reactors.

  13. Self-Powered Neutron Detector Calibration Using a Large Vertical Irradiation Hole of HANARO

    Science.gov (United States)

    Kim, Myong-Seop; Park, Byung-Gun; Kang, Gi-Doo

    2018-01-01

    A calibration technology of the self-powered neutron detectors (SPNDs) using a large vertical irradiation hole of HANARO is developed. The 40 Rh-SPNDs are installed on the polycarbonate plastic support, and the gold wires with the same length as the effective length of the rhodium emitter of the SPND are also installed to measure the neutron flux on the SPND. They are irradiated at a low reactor power, and the SPND current is measured using the pico-ammeter. The external gamma-rays which affect the SPND current response are analyzed using the Monte Carlo simulation for various irradiation conditions in HANARO. It is confirmed that the effect of the external gamma-rays to the SPND current is dependent on the reactor characteristics, and that it is affected by materials around the detector. The current signals due to the external gamma-rays can be either positive or negative, in that the net flow of the current may be either in the same or the opposite direction as the neutron-induced current by the rhodium emitter. From the above procedure, the effective calibration methodology of multiple SPNDs using the large hole of HANARO is developed. It could be useful for the calibration experiment of the neutron detectors in the research reactors.

  14. Characterization of a high repetition-rate laser-driven short-pulsed neutron source

    Science.gov (United States)

    Hah, J.; Nees, J. A.; Hammig, M. D.; Krushelnick, K.; Thomas, A. G. R.

    2018-05-01

    We demonstrate a repetitive, high flux, short-pulsed laser-driven neutron source using a heavy-water jet target. We measure neutron generation at 1/2 kHz repetition rate using several-mJ pulse energies, yielding a time-averaged neutron flux of 2 × 105 neutrons s‑1 (into 4π steradians). Deuteron spectra are also measured in order to understand source characteristics. Analyses of time-of-flight neutron spectra indicate that two separate populations of neutrons, ‘prompt’ and ‘delayed’, are generated at different locations. Gamma-ray emission from neutron capture 1H(n,γ) is also measured to confirm the neutron flux.

  15. High power ubitron-klystron

    International Nuclear Information System (INIS)

    Balkcum, A.J.; McDermott, D.B.; Luhmann, N.C. Jr.

    1997-01-01

    A coaxial ubitron is being considered as the rf driver for the Next Linear Collider (NLC). Prior simulation of a traveling-wave ubitron using a self-consistent code found that 200 MW of power and 53 dB of gain could be achieved with 37% efficiency. In a ubiron-klystron, a series of cavities are used to obtain an even tighter electron bunch for higher efficiency. A small-signal theory of the ubitron-klystron shows that gain scales with the square of the cavity separation distance. A linear stability theory has also been developed. Verification of the stability theory has been achieved using the 2-12-D PIC code, MAGIC, and the particle-tracing code. Saturation characteristics of the amplifier will be presented using both MAGIC and a simpler self-consistent slow-timescale code currently under development. The ubitron can also operate as a compact, highly efficient oscillator. Cavities only two wiggler periods in length have yielded up to 40% rf conversion efficiency in simulation. An initial oscillator design for directed energy applications will also be presented

  16. Are some of the luminous high-latitude stars accretion-powered runaways?

    International Nuclear Information System (INIS)

    Leonard, P.J.T.; Hills, J.G.; Dewey, R.J.

    1992-01-01

    It is well known that (1) runaway stars can be produced via supernova explosions in close binary systems, (2) most of such runaways should possess neutron star companions, and (3) neutron stars receive randomly oriented kicks of ≅ 100 to 200 km s -1 at birth. We find that this kick sometimes has the right amplitude and direction to make the neutron star fall into the runaway. Accretion onto a neutron star is a source of energy that is roughly an order of magnitude more mass efficient than nuclear burning. Thus, runaways containing neutron stars may live much longer than would normally be expected, which would allow them to travel great distances from their birthplaces during their lifetimes. Some of the early B-type stars far from the Galactic plane and the high-latitude F and G-type supergiants may be accretion-powered runaway stars

  17. Neutron emission probability at high excitation and isospin

    International Nuclear Information System (INIS)

    Aggarwal, Mamta

    2005-01-01

    One-neutron and two-neutron emission probability at different excitations and varying isospin have been studied. Several degrees of freedom like deformation, rotations, temperature, isospin fluctuations and shell structure are incorporated via statistical theory of hot rotating nuclei

  18. First experiments with a liquid-lithium based high-intensity 25-keV neutron source

    International Nuclear Information System (INIS)

    Paul, M.

    2014-01-01

    A high-intensity neutron source based on a Liquid-Lithium Target (LiLiT) and the 7 Li(p,n) reaction was developed at SARAF (Soreq Applied Research Accelerator Facility, Israel) and is used for nuclear astrophysics experiments. The setup was commissioned with a 1.3 mA proton beam at 1.91 MeV, producing a neutron yield of ~ 2 ×10 10 n/s, more than one order of magnitude larger than conventional 7 Li(p,n)-based neutron sources and peaked at ~25 keV. The LiLiT device consists of a high-velocity (> 4 m/s) vertical jet of liquid lithium (~200 °C) whose free surface is bombarded by the proton beam. The lithium jet acts both as the neutron-producing target and as a power beam dump. The target dissipates a peak power areal density of 2.5 kW/cm 2 and peak volume density of 0.5 MW/cm 3 with no change of temperature or vacuum regime in the vacuum chamber. Preliminary results of Maxwellian-averaged cross section measurements for stable isotopes of Zr and Ce, performed by activation in the neutron flux of LiLiT, and nuclear-astrophysics experiments in planning will be described. (author)

  19. Simplified High-Power Inverter

    Science.gov (United States)

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  20. Code of practice for in-core instrumentation for neutron fluence rate (flux) measurements in power reactors

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    This standard applies to in-core (on-line) neutron detectors and instrumentation which is designed for safety, information or control purposes. It also applies to components in so far as these components are contained within the primary envelope of the reactor. The detector types usually used are dc ionization chambers and self-powered neutron detectors

  1. Review of Power System Stability with High Wind Power Penetration

    DEFF Research Database (Denmark)

    Hu, Rui; Hu, Weihao; Chen, Zhe

    2015-01-01

    analyzing methods and stability improvement approaches. With increasing wind power penetration, system balancing and the reduced inertia may cause a big threaten for stable operation of power systems. To mitigate or eliminate the wind impacts for high wind penetration systems, although the practical......This paper presents an overview of researches on power system stability with high wind power penetration including analyzing methods and improvement approaches. Power system stability issues can be classified diversely according to different considerations. Each classified issue has special...... and reliable choices currently are the strong outside connections or sufficient reserve capacity constructions, many novel theories and approaches are invented to investigate the stability issues, looking forward to an extra-high penetration or totally renewable resource based power systems. These analyzing...

  2. Neutron fluence measurement in the cavity of Balakovo nuclear power plant, unit 3

    International Nuclear Information System (INIS)

    Voorbraak, W.P.; Baard, J.H.; Paardekooper, A.; Nolthenius, H.J.

    1996-12-01

    An international benchmark exercise has been organized by the Russian GOSATOMNADZOR. The aim was to reduce the uncertainty of fluence measurements in Nuclear Power Plants in particular VVER-1000 reactors. The benchmark was set up in the cavity of the Balakovo NPP 3. Eight institutes were involved. This report presents the results obtained by ECN. From this report, it can be concluded that the results of the relative large monitor set (13 different reaction rates with overlapping response regions) point to possible imperfections in the calculated neutron spectra. However the experimental information is not powerful enough to reduce the uncertainty of the neutron fluence rate especially in the energy region between 0.1 and 0.5 MeV below 50 percent. (orig.)

  3. Effect of high fluence neutron irradiation on transport properties of thermoelectrics

    Science.gov (United States)

    Wang, H.; Leonard, K. J.

    2017-07-01

    Thermoelectric materials were subjected to high fluence neutron irradiation in order to understand the effect of radiation damage on transport properties. This study is relevant to the NASA Radioisotope Thermoelectric Generator (RTG) program in which thermoelectric elements are exposed to radiation over a long period of time in space missions. Selected n-type and p-type bismuth telluride materials were irradiated at the High Flux Isotope Reactor with a neutron fluence of 1.3 × 1018 n/cm2 (E > 0.1 MeV). The increase in the Seebeck coefficient in the n-type material was partially off-set by an increase in electrical resistivity, making the power factor higher at lower temperatures. For the p-type materials, although the Seebeck coefficient was not affected by irradiation, electrical resistivity decreased slightly. The figure of merit, zT, showed a clear drop in the 300-400 K range for the p-type material and an increase for the n-type material. Considering that the p-type and n-type materials are connected in series in a module, the overall irradiation damages at the device level were limited. These results, at neutron fluences exceeding a typical space mission, are significant to ensure that the radiation damage to thermoelectrics does not affect the performance of RTGs.

  4. Electronic DC transformer with high power density

    NARCIS (Netherlands)

    Pavlovský, M.

    2006-01-01

    This thesis is concerned with the possibilities of increasing the power density of high-power dc-dc converters with galvanic isolation. Three cornerstones for reaching high power densities are identified as: size reduction of passive components, reduction of losses particularly in active components

  5. DOSIMETRIC response of a REM-500 in low energy neutron fields typical of nuclear power plants.

    Science.gov (United States)

    Aslam; Matysiak, W; Atanackovic, J; Waker, A J

    2012-06-01

    This study investigates the response of a REM-500 to assess neutron quality factor and dose equivalent in low energy neutron fields, which are commonly encountered in the workplace environment of nuclear power stations. The McMaster University 3 MV Van de Graaff accelerator facility was used to measure the response of the instrument in monoenergetic neutron fields in the energy range 51 to 727 keV by bombarding a thin LiF target with 1.93-2.50 MeV protons. The energy distribution of the neutron fields produced in the facility was measured by a (3)He filled gas ionization chamber. The MCA mode of the REM-500 instrument was used to collect lineal energy distributions at varying neutron energies and to calculate the frequency and dose-mean lineal energies. The effective quality factor, Q-, was also calculated using the values of Q(y)listed in the REM-500 operation manual and compared with those of ICRP 60. The authors observed a continuously increasing trend in y - F, y-D, and Q-with an increase in neutron energy. It is interesting to note that standard tissue equivalent proportional counters (TEPCs) filled with tissue equivalent(TE) gas give rise to a similar trend for these microdosimetric quantities of interest in the same energy range; however, the averages calculated in this study are larger by about 15%compared to a TEPC filled with propane-based TE gas probably because of the larger stopping power of protons in propane compared to TE gas. These somewhat larger event sizes did not result in any significant increase in the Q-compared to those obtained from a TEPC filled with TE gas and were found to be in good agreement with other measurements reported earlier at corresponding neutron energies. The instrument quality factor response, R(Q), defined as the ratio of measured quality factor to the calculated quality factor in an ICRU tissue sphere,was found to vary with neutron energy. The instrument response,R(Q), was ~0.6 at 727 keV, which deteriorates further to

  6. Real-time database for high resolution neutron monitor measurements

    Energy Technology Data Exchange (ETDEWEB)

    Steigies, Christian T.; Rother, Oliver M.; Wimmer-Schweingruber, Robert F.; Heber, Bernd [IEAP, Christian-Albrechts-Universitaet zu Kiel (Germany)

    2008-07-01

    The worldwide network of standardised neutron monitors is, after 50 years, still the state-of-the-art instrumentation to measure spectral variations of the primary cosmic ray component. These measurements are an ideal complement to space based cosmic ray measurements. Data from the approximately 50 IGY and NM64 neutron monitors is stored locally but also available through data collections sites like the World Data Center (WDC) or the IZMIRAN ftp server. The data from the WDC is in a standard format, but only hourly values are available. IZMIRAN collects the data in the best available time resolution, but the data arrives on the ftp server only hours, sometimes days, after the measurements. Also, the high time-resolution measurements of the different stations do not have a common format, a conversion routine for each station is needed before they can be used for scientific analysis. Supported by the 7th framework program of the European Commission, we are setting up a real-time database where high resolution cosmic ray measurements will be stored and accessible immediately after the measurement. Stations that do not have 1-minute resolution measurements will be upgraded to 1-minute or better resolution with an affordable standard registration system, that will submit the measurements to the database via the internet in real-time.

  7. High Ni austenite stainless steel resistant to neutron irradiation degradation

    International Nuclear Information System (INIS)

    Yonezawa, Toshio; Iwamura, Toshihiko; Kanasaki, Hiroshi; Fujimoto, Koji; Nakata, Shizuo; Ajiki, Kazuhide; Nakamura, Mitsuhiro.

    1997-01-01

    The composition of the stainless steel of the present invention comprises from 0.005 to 0.08% of C, up to 3% of Mn, up to 0.2% of Si+P+S, from 25 to 40% of Ni, from 25 to 40% of Cr, up to 3% of Mo, up to 0.3% of Nb+Ta, up to 0.3% of Ti, up to 0.001% of B and the balance of Fe. A solid solubilization treatment at a temperature of from 1,000 to 1,150degC is applied to the stainless steel having the composition. The stainless steel is excellent in stress corrosion cracking-resistance at a working circumstance of a LWR type reactor (high temperature and high pressure water at from 270 to 350degC/from 70 to 160 atm even after undergoing neutron irradiation of about 1 x 10 22 n/cm 2 (E>1 MeV) which is a maximum neutron irradiation amount undergone till the final stage of the working life of the LWR-type reactor. In addition, the average thermal expansion coefficient at from room temperature to 400degC ranges from 15x10 -6 - 19x10 -6 /K. (I.N.)

  8. Optimization of the Neutronics of the Advanced High Temperature Reactor

    International Nuclear Information System (INIS)

    Zakova, Jitka; Talamo, Alberto

    2006-01-01

    In these studies, we have investigated the neutronic and safety performance of the Advanced High Temperature Reactor (AHTR) for plutonium and uranium fuels and we extended the analysis to five different coolants. The AHTR is a graphite-moderated and molten salt-cooled high temperature reactor, which takes advantage of the TRISO particles technology for the fuel utilization. The conceptual design of the core, proposed at the Oak Ridge National Laboratory, aims to provide an alternative to helium as coolant of high-temperature reactors for industrial applications like hydrogen production. We evaluated the influence of the radial reflector on the criticality of the core for the uranium and plutonium fuels and we focused on the void coefficient of 5 different molten salts; since the safety of the reactor is enhanced also by the large and negative coefficient of temperature, we completed our investigation by observing the keff changes when the graphite temperature varies from 300 to 1800 K. (authors)

  9. High-resolution investigations of edge effects in neutron imaging

    International Nuclear Information System (INIS)

    Strobl, M.; Kardjilov, N.; Hilger, A.; Kuehne, G.; Frei, G.; Manke, I.

    2009-01-01

    Edge enhancement is the main effect measured by the so-called inline or propagation-based neutron phase contrast imaging method. The effect has originally been explained by diffraction, and high spatial coherence has been claimed to be a necessary precondition. However, edge enhancement has also been found in conventional imaging with high resolution. In such cases the effects can produce artefacts and hinder quantification. In this letter the edge effects at cylindrical shaped samples and long straight edges have been studied in detail. The enhancement can be explained by refraction and total reflection. Using high-resolution imaging, where spatial resolutions better than 50 μm could be achieved, refraction and total reflection peaks - similar to diffraction patterns - could be separated and distinguished.

  10. Industrial development of neutron detectors, fission chambers, self powered detectors, ionization chambers

    International Nuclear Information System (INIS)

    Constans, H.; Coville, P.; Guerre, J.

    1975-01-01

    Reactor control requires the determination of neutron flux at all times. The needed characteristics lead to use of several types of detectors: boron lined counters, boron lined ionization chambers, fission ionization chambers and self powered detectors. The principle of the reaction involved the fabrication requirements, the different modes of utilization and the characteristics obtained are examined for each detector. The problem of electric connections in the active area has been solved by developing ''integrated cables'' [fr

  11. High power CW linac in PNC

    International Nuclear Information System (INIS)

    Toyama, S.; Wang, Y.L.; Emoto, T.

    1994-01-01

    Power Reactor and Nuclear Fuel Development Corporation (PNC) is developing a high power electron linac for various applications. The electron beam is accelerated in CW operation to get maximum beam current of 100 mA and energy of 10 MeV. Crucial components such as a high power L-band klystron and a high power traveling wave resonant ring (TWRR) accelerator guides were designed and manufactured and their performance were examined. These design and results from the recent high power RF tests were described in this paper. (author)

  12. Use of a high repetition rate neutron generator for in vivo body composition measurements via neutron inelastic scattering

    International Nuclear Information System (INIS)

    Kehayias, J.J.; Ellis, K.J.; Cohn, S.H.; Weinlein, J.H.

    1986-01-01

    A small D-T neutron generator with a high pulse rate is used for the in vivo measurement of body carbon, oxygen and hydrogen. The core of the neutron generator is a 13 cm-long Zetatron tube pulsed at a rate of 10 kHz delivering 10 3 to 10 4 neutrons per pulse. A target-current feedback system regulates the source of the accelerator to assure constant neutron output. Carbon is measured by detecting the 4.44 MeV γ-rays from inelastic scattering. The short half-life of the 4.44 MeV state of carbon requires detection of the γ-rays during the 10 μs neutron pulse. Generators with low pulsing rate were found inappropriate for carbon measurements because of their low duty-cycle (high neutron output during the pulse). In vivo measurements were performed with normal volunteers using a scanning bed facility for a dose less than 25 mrem. This technique offers medical as well as general bulk analysis applications. 8 refs., 5 figs

  13. High Power Density Power Electronic Converters for Large Wind Turbines

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk

    . For these VSCs, high power density is required due to limited turbine nacelle space. Also, high reliability is required since maintenance cost of these remotely located wind turbines is quite high and these turbines operate under harsh operating conditions. In order to select a high power density and reliability......In large wind turbines (in MW and multi-MW ranges), which are extensively utilized in wind power plants, full-scale medium voltage (MV) multi-level (ML) voltage source converters (VSCs) are being more preferably employed nowadays for interfacing these wind turbines with electricity grids...... VSC solution for wind turbines, first, the VSC topology and the switch technology to be employed should be specified such that the highest possible power density and reliability are to be attained. Then, this qualitative approach should be complemented with the power density and reliability...

  14. ICF ignition capsule neutron, gamma ray, and high energy x-ray images

    Science.gov (United States)

    Bradley, P. A.; Wilson, D. C.; Swenson, F. J.; Morgan, G. L.

    2003-03-01

    Post-processed total neutron, RIF neutron, gamma-ray, and x-ray images from 2D LASNEX calculations of burning ignition capsules are presented. The capsules have yields ranging from tens of kilojoules (failures) to over 16 MJ (ignition), and their implosion symmetry ranges from prolate (flattest at the hohlraum equator) to oblate (flattest towards the laser entrance hole). The simulated total neutron images emphasize regions of high DT density and temperature; the reaction-in-flight neutrons emphasize regions of high DT density; the gamma rays emphasize regions of high shell density; and the high energy x rays (>10 keV) emphasize regions of high temperature.

  15. Liquid lithium target as a high intensity, high energy neutron source

    Science.gov (United States)

    Parkin, Don M.; Dudey, Norman D.

    1976-01-01

    This invention provides a target jet for charged particles. In one embodiment the charged particles are high energy deuterons that bombard the target jet to produce high intensity, high energy neutrons. To this end, deuterons in a vacuum container bombard an endlessly circulating, free-falling, sheet-shaped, copiously flowing, liquid lithium jet that gushes by gravity from a rectangular cross-section vent on the inside of the container means to form a moving web in contact with the inside wall of the vacuum container. The neutrons are produced via break-up of the beam in the target by stripping, spallation and compound nuclear reactions in which the projectiles (deuterons) interact with the target (Li) to produce excited nuclei, which then "boil off" or evaporate a neutron.

  16. Liquid lithium target as a high intensity, high energy neutron source

    International Nuclear Information System (INIS)

    Parkin, D.M.; Dudey, N.D.

    1976-01-01

    The invention described provides a target jet for charged particles. In one embodiment the charged particles are high energy deuterons that bombard the target jet to produce high intensity, high energy neutrons. To this end, deuterons in a vacuum container bombard an endlessly circulating, free-falling, sheet-shaped, copiously flowing, liquid lithium jet that gushes by gravity from a rectangular cross-section vent on the inside of the container means to form a moving web in contact with the inside wall of the vacuum container. The neutrons are produced via break-up of the beam in the target by stripping, spallation and compound nuclear reactions in which the projectiles (deuterons) interact with the target (Li) to produce excited nuclei, which then ''boil off'' or evaporate a neutron

  17. High Power Fiber Laser Test Bed

    Data.gov (United States)

    Federal Laboratory Consortium — This facility, unique within DoD, power-combines numerous cutting-edge fiber-coupled laser diode modules (FCLDM) to integrate pumping of high power rare earth-doped...

  18. ELBE Center for High-Power Radiation Sources

    Directory of Open Access Journals (Sweden)

    Peter Dr. Michel

    2016-01-01

    Full Text Available In the ELBE Center for High-Power Radiation Sources, the superconducting linear electron accelerator ELBE, serving  two free electron lasers, sources for intense coherent THz radiation, mono-energetic positrons, electrons, γ-rays, a neutron time-of-flight system as well as two synchronized ultra-short pulsed Petawatt laser systems are collocated. The characteristics of these beams make the ELBE center a unique research instrument for a variety of external users in fields ranging from material science over nuclear physics to cancer research, as well as scientists of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR.

  19. The neutron spin-echo spectrometer: a new high resolution technique in neutron scattering

    International Nuclear Information System (INIS)

    Nicholson, L.K.

    1981-01-01

    The neutron spin-echo (NSE) spectrometer provides the highest energy resolution available in neutron scattering experiments. The article describes the principles behind the first NSE spectrometer (at the Institute Laue-Langevin, Grenoble, France) and, as an example of one of its applications, some recent results on polymer chain dynamics are presented. (author)

  20. High resolution neutron spectroscopy - a tool for the investigation of dynamics of polymers and soft matter

    International Nuclear Information System (INIS)

    Monkenbusch, M.; Richter, D.

    2007-01-01

    Neutron scattering, with the ability to vary the contrast of molecular items by hydrogen/deuterium exchanges, is an invaluable tool for soft matter research. Besides the structural information on the mesoscopic scale that is obtained by diffraction methods like small angle neutron scattering, the slow dynamics of molecular motion on mesoscopic scale is accessible by high resolution neutron spectroscopy. The basic features of neutron backscattering spectroscopy, and in particular neutron spin-echo spectroscopy, are presented, in combination with illustrations of results from polymer melt dynamics to protein dynamics which are obtained by these techniques. (authors)

  1. Neutron emission in fission of highly excited californium nuclei (E*=76 MeV)

    International Nuclear Information System (INIS)

    Blinov, M.V.; Bordyug, V.M.; Kozulin, Eh.M.; Mozhaev, A.N.; Levitovich, M.; Muzychka, Yu.A.; Penionzhkevich, Yu.Eh.; Pustyl'nik, B.I.

    1990-01-01

    The differential cross sections for neutron production in the fission of highly excited californium nuclei formed in the 238 U+ 12 C (105 MeV) reaction have been measured. From the analysis of the experimental data is follows that the number of pre-fission neutrons substantially exceeds the value obtained in the framework of the standard statistical model. The saddle-to-scission time of the excited nucleus is estimated on the basis of the neutron multiplicity. The dependences of the neutron number and neutron average energies upon the fragment mass are determined

  2. Nuclear based diagnostics in high-power laser applications

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, Marc; Sonnabend, Kerstin; Harres, Knut; Otten, Anke; Roth, Markus [TU Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Vogt, Karsten; Bagnoud, Vincent [GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt (Germany)

    2010-07-01

    High-power lasers allow focused intensities of >10{sup 18} W/cm{sup 2}. During the laser-solid interaction, an intense relativistic electron current is injected from the plasma into the target. One challenge is to characterize the electron dynamic close to the interaction region. Moreover, next generation high-power laser proton acceleration leads to high proton fluxes, which require novel, nuclear diagnostic techniques. We present an activation-based nuclear pyrometry for the investigation of electrons generated in relativistic laser-solid interactions. We use novel activation targets consisting of several isotopes with different photo-neutron disintegration thresholds. The electrons are decelerated inside the target via bremsstrahlung processes. The high-energy bremsstrahlung induces photo-nuclear reactions. In this energy range no disturbing low energy effects are important. Via the pyrometry the Reconstruction of the absolute yield, spectral and spatial distribution of the electrons is possible. For the characterization of proton beams we present a nuclear activation imaging spectroscopy (NAIS). The diagnostic is based on proton-neutron disintegration reactions of copper stacked in consecutive layers. An autoradiography of copper layers leads to spectrally and spatially reconstruction of the beam profile.

  3. Study on the sensitivity of Self-Powered Neutron Detectors (SPND) and its change due to burn-up

    International Nuclear Information System (INIS)

    Cho, Gyuseong; Lee, Wanno; Yoon, Jeong-Hyoun.

    1996-01-01

    Self-Powered Neutron Detectors (SPND) are currently used to estimate the power generation distribution and fuel burn-up in several nuclear power reactors in Korea. While they have several advantages such as small size, low cost, and relatively simple electronics required in conjunction with its usage, it has some intrinsic problems of the low level of output current, a slow response time, the rapid change of sensitivity which makes it difficult to use for a long term. In this paper, Monte Carlo simulation was accomplished to calculate the escape probability as a function of the birth position for the typical geometry of rhodium-based SPNDs. Using the simulation result, the burn-up profile of rhodium number density and the neutron sensitivity is calculated as a function of burn-up time in the reactor. The sensitivity of the SPND decreases non-linearly due to the high absorption cross-section and the non-uniform burn-up of rhodium in the emitter rod. The method used here can be applied to the analysis of other types of SPNDs and will be useful in the optimum design of new SPNDs for long-term usage. (author)

  4. Radiological safety aspects associated with the handling, storage and disposal of self power neutron detectors in TAPS - 3 and 4

    International Nuclear Information System (INIS)

    Parida, B.K.; Mudgal, B.; Ghadigoankar, V.R.; Niraj; Ashok; Pati, C.K.; Patil, P.M.; Pawar, S.K.; Varadhan, R.S.

    2006-01-01

    At Tarapur Atomic Power Station 3 and 4, 540 MWe Pressurised Heavy Water Reactors, core being large in size requires a continuous in core monitoring for local flux disturbances. Nearly 200 Self Powered Neutron Detectors (SPNDs) of the Straight Individually Replaceable (SIR) type are distributed in the reactor core. For purpose of reactor regulation and protection, cobalt SPNDs that have a prompt response for changes in power is used for in-core flux mapping, vanadium SPNDs that provide accurate measure of neutron flux, even though having slow response is used In core SPNDs are placed in Vertical Flux Units (VFU) and Horizontal Flux Units (HFUs). These SPNDs were to be replaced at regular intervals to meet the design intent. Cobalt SPNDs have dose rates of the order of 1000 Gy/h and the Mineral Insulated (MI) cables of Vanadium SPNDs have dose rates of the order of 100 Gy/h. So far 3 Cobalt SPNDs were removed from HFUs and are being stored in lead shielding inside spent fuel storage facility. These high active components were handled with meticulous planning with lowest exposures to the maintainers. Radiological safety aspects of handling and storage of SPNDs are discussed in this report. (author)

  5. Long-term performance of the CANDU-type of vanadium self-powered neutron detectors in NRU

    Energy Technology Data Exchange (ETDEWEB)

    Leung, T.C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)]. E-mail: leungt@aecl.ca

    2007-07-01

    The CANDU-type of in-core vanadium self-powered neutron flux detectors have been installed in NRU to monitor the axial neutron flux distributions adjacent to the loop fuel test sites since 1996. This paper describes how the thermal neutron fluxes were measured at two monitoring sites, and presents a method of correcting the vanadium burn-up effect, which can be up to 2 to 3% per year, depending on the detector locations in the reactor. It also presents the results of measurements from neutron flux detectors that have operated for over eight-years in NRU. There is good agreement between the measured and simulated neutron fluxes, to within {+-} 6.5%, and the long-term performance of the CANDU-type of vanadium neutron flux detectors in NRU is satisfactory. (author)

  6. Power measurement of the RA-3 reactor using the neutron noise technique and 16N

    International Nuclear Information System (INIS)

    Gomez, Angel

    2003-01-01

    This work describes a measurement method based on the neutron noise technique which is used for determining the relation between the power and the currents of two ionization chambers. These chambers are sensitive to the gamma radiation from the 16 N decay produced in the RA-3 reactor core. The power during operation is obtained from the calibration factors by measuring those currents. As this calibration factors depend on the cooler flow that circulates in the reactor core and in the 16 N measuring system, an estimator, that is a function of the ratio of this currents, is proposed in order to detect flow changes. (author)

  7. High Power Wireless Transfer : For Charging High Power Batteries

    OpenAIRE

    Gill, Himmat

    2017-01-01

    Wireless power transfer (WPT) is developing with emerging of new technologies that has made it possible to transfer electricity over certain distances without any physical contact, offering significant benefits to modern automation systems, medical applications, consumer electronic, and especially in electric vehicle systems. The goal of this study is to provide a brief review of existing compensation topologies for the loosely coupled transformer. The technique used to simulate a co...

  8. High dose neutron irradiation damage in beryllium as blanket material

    Energy Technology Data Exchange (ETDEWEB)

    Chakin, V.P. E-mail: fae@niiar.ru; Kazakov, V.A.; Teykovtsev, A.A.; Pimenov, V.V.; Shimansky, G.A.; Ostrovsky, Z.E.; Suslov, D.N.; Latypov, R.N.; Belozerov, S.V.; Kupriyanov, I.B. E-mail: vniinm.400@g23.relkom.ru

    2001-11-01

    The paper presents the investigation results of beryllium products that operated in the SM and BOR-60 reactors up to neutron doses of 2.8x10{sup 22} and 8.0x10{sup 22} cm{sup -2} (E>1 MeV), respectively. The calculated and experimental data are given on helium and tritium accumulation, swelling, micro-hardness and thermal conductivity. The microstructural investigation results of irradiated beryllium are also presented. It is shown that the rate of helium and tritium accumulation in beryllium in the SM and BOR-60 reactors is high enough, which is of interest from the viewpoint of modeling the working conditions of the DEMO fusion reactor. Swelling of beryllium at irradiation temperature of 70-150 deg. C and neutron fluence of 2.8x10{sup 22} cm{sup -2} (E>1 MeV) makes up 0.8-1.5%, at 400 deg. C and fluence of 8x10{sup 22} cm{sup -2} (E>1 MeV)-3.2-5.0%. Irradiation hardening and decrease of thermal conductivity strongly depend on the irradiation temperature and are more significant at reduced temperatures. All results presented in the paper were analyzed with due account of the supposed working parameters of the DEMO fusion reactor blanket.

  9. High dose neutron irradiation damage in beryllium as blanket material

    International Nuclear Information System (INIS)

    Chakin, V.P.; Kazakov, V.A.; Teykovtsev, A.A.; Pimenov, V.V.; Shimansky, G.A.; Ostrovsky, Z.E.; Suslov, D.N.; Latypov, R.N.; Belozerov, S.V.; Kupriyanov, I.B.

    2001-01-01

    The paper presents the investigation results of beryllium products that operated in the SM and BOR-60 reactors up to neutron doses of 2.8x10 22 and 8.0x10 22 cm -2 (E>1 MeV), respectively. The calculated and experimental data are given on helium and tritium accumulation, swelling, micro-hardness and thermal conductivity. The microstructural investigation results of irradiated beryllium are also presented. It is shown that the rate of helium and tritium accumulation in beryllium in the SM and BOR-60 reactors is high enough, which is of interest from the viewpoint of modeling the working conditions of the DEMO fusion reactor. Swelling of beryllium at irradiation temperature of 70-150 deg. C and neutron fluence of 2.8x10 22 cm -2 (E>1 MeV) makes up 0.8-1.5%, at 400 deg. C and fluence of 8x10 22 cm -2 (E>1 MeV)-3.2-5.0%. Irradiation hardening and decrease of thermal conductivity strongly depend on the irradiation temperature and are more significant at reduced temperatures. All results presented in the paper were analyzed with due account of the supposed working parameters of the DEMO fusion reactor blanket

  10. A high-pressure cell for neutron crystal spectrometry

    International Nuclear Information System (INIS)

    Buras, B.; Kofoed, W.; Lebech, B.; Baeckstroem, G.

    1977-04-01

    Three fixed-scattering-angle methods for neutron scattering powder measurements using double- and triple-axis crystal spectrometers were tested: (1) the analyzer-scan method (AS), (2) the monochromator-scan method (MS), and (3) the monochromator-analyzer scan method (MAS). A high-pressure cell, primarily for use in powder diffraction measurements, with scattering angles of 30 0 , 60 0 , 90 0 and 120 0 and a sample volume of about 0.8 cm 3 was constructed and used in conjunction with the MS and MAS methods. At room temperature, this cell makes it possible to make measurements at pressures up to about 40 kbar and up to about 30 kbar at 300 0 C. The report includes a description of the diffraction methods and of the high-pressure cell. A few examples of experimental results are also given. (Auth.)

  11. Formulation of detector response function to calculate the power density profiles using in-core neutron detectors

    International Nuclear Information System (INIS)

    Ahmed, S. A.; Peter, J. K.; Semmler, W.; Shultis, J. K.

    2007-01-01

    By measuring neutron fluxes at different locations throughout a core, it's possible to derive the power-density profile P k (W cm - 3), at an axial depth z of fuel rod k. Micro-pocket fission detectors (MPFD) have been fabricated to perform such in-core neutron flux measurements. The purpose of this study is to develop a mathematical model to obtain axial power density distributions in the fuel rods from the in-core responses of the MPFDs

  12. High Neutron Fluence Survivability Testing of Advanced Fiber Bragg Grating Sensors

    International Nuclear Information System (INIS)

    Fielder, Robert S.; Klemer, Daniel; Stinson-Bagby, Kelly L.

    2004-01-01

    The motivation for the reported research was to support NASA space nuclear power initiatives through the development of advanced fiber optic sensors for space-based nuclear power applications. The purpose of the high-neutron fluence testing was to demonstrate the survivability of fiber Bragg grating (FBG) sensors in a fission reactor environment. 520 FBGs were installed in the Ford reactor at the University of Michigan. The reactor was operated for 1012 effective full power hours resulting in a maximum neutron fluence of approximately 5x1019 n/cm2, and a maximum gamma dose of 2x103 MGy gamma. This work is significant in that, to the knowledge of the authors, the exposure levels obtained are approximately 1000 times higher than for any previously published experiment. Four different fiber compositions were evaluated. An 87% survival rate was observed for fiber Bragg gratings located at the fuel centerline. Optical Frequency Domain Reflectometry (OFDR), originally developed at the NASA Langley Research Center, can be used to interrogate several thousand low-reflectivity FBG strain and/or temperature sensors along a single optical fiber. A key advantage of the OFDR sensor technology for space nuclear power is the extremely low mass of the sensor, which consists of only a silica fiber 125μm in diameter. The sensors produced using this technology will fill applications in nuclear power for current reactor plants, emerging Generation-IV reactors, and for space nuclear power. The reported research was conducted by Luna Innovations and was funded through a Small Business Innovative Research (SBIR) contract with the NASA Glenn Research Center

  13. Non-equilibrium thermodynamics and energy distribution function of neutron gas in constant power reactor under coupling of neutrons and medium

    International Nuclear Information System (INIS)

    Hayasaka, Hideo

    1983-01-01

    The thermodynamics and the energy distribution function of the neutron gas in a constant power reactor are considered, taking into account the burn-up of fuel. To separate the secular motion of neutrons owing to fuel burn-up and the microscopic fluctuations of neutrons around this motion, a long time of the order of several months is divided into m equal intervals, and the respective states corresponding to m small time intervals are treated as quasi-stationary states. The local energy distribution function of the neutron gas in the quasi-stationary state is given by a generalized Boltzmann distribution specified by the respective generalized activity coefficient for each subsystem. The effects of fuel burn-up on the respective distribution functions for successive small time intervals are taken into account through various quantities relating to reactor physics, depending upon the fuel burn-up, by successive approximation. (author)

  14. Feasibility studies on large sample neutron activation analysis using a low power research reactor

    International Nuclear Information System (INIS)

    Gyampo, O.

    2008-06-01

    Instrumental neutron activation analysis (INAA) using Ghana Research Reactor-1 (GHARR-1) can be directly applied to samples with masses in grams. Samples weights were in the range of 0.5g to 5g. Therefore, the representativity of the sample is improved as well as sensitivity. Irradiation of samples was done using a low power research reactor. The correction for the neutron self-shielding within the sample is determined from measurement of the neutron flux depression just outside the sample. Correction for gamma ray self-attenuation in the sample was performed via linear attenuation coefficients derived from transmission measurements. Quantitative and qualitative analysis of data were done using gamma ray spectrometry (HPGe detector). The results of this study on the possibilities of large sample NAA using a miniature neutron source reactor (MNSR) show clearly that the Ghana Research Reactor-1 (GHARR-1) at the National Nuclear Research Institute (NNRI) can be used for sample analyses up to 5 grams (5g) using the pneumatic transfer systems.

  15. High Power laser power conditioning system new discharge circuit research

    CERN Document Server

    Li Yi; Peng Han Sheng; Zhou Pei Zhang; Zheng Wan Guo; Guo Lang Fu; Chen Li Hua; Chen De Hui; Lai Gui You; Luan Yong Ping

    2002-01-01

    The new discharge circuit of power conditioning system for high power laser is studied. The theoretical model of the main discharge circuit is established. The pre-ionization circuit is studied in experiment. In addition, the explosion energy of the new large xenon lamp is successfully measured. The conclusion has been applied to 4 x 2 amplifier system

  16. Development of an inconel self powered neutron detector for in-core reactor monitoring

    Science.gov (United States)

    Alex, M.; Ghodgaonkar, M. D.

    2007-04-01

    The paper describes the development and testing of an Inconel600 (2 mm diameter×21 cm long) self-powered neutron detector for in-core neutron monitoring. The detector has 3.5 mm overall diameter and 22 cm length and is integrally coupled to a 12 m long mineral insulated cable. The performance of the detector was compared with cobalt and platinum detectors of similar dimensions. Gamma sensitivity measurements performed at the 60Co irradiation facility in 14 MR/h gamma field showed values of -4.4×10 -18 A/R/h/cm (-9.3×10 -24 A/ γ/cm 2-s/cm), -5.2×10 -18 A/R/h/cm (-1.133×10 -23 A/ γ/cm 2-s/cm) and 34×10 -18 A/R/h/cm (7.14×10 -23 A/ γ/cm 2-s/cm) for the Inconel, Co and Pt detectors, respectively. The detectors together with a miniature gamma ion chamber and fission chamber were tested in the in-core Apsara Swimming Pool type reactor. The ion chambers were used to estimate the neutron and gamma fields. With an effective neutron cross-section of 4b, the Inconel detector has a total sensitivity of 6×10 -23 A/nv/cm while the corresponding sensitivities for the platinum and cobalt detectors were 1.69×10 -22 and 2.64×10 -22 A/nv/cm. The linearity of the detector responses at power levels ranging from 100 to 200 kW was within ±5%. The response of the detectors to reactor scram showed that the prompt response of the Inconel detector was 0.95 while it was 0.7 and 0.95 for the platinum and cobalt self-powered detectors, respectively. The detector was also installed in the horizontal flux unit of 540 MW Pressurised Heavy Water Reactor (PHWR). The neutron flux at the detector location was calculated by Triveni code. The detector response was measured from 0.02% to 0.07% of full power and showed good correlation between power level and detector signals. Long-term tests and the dynamic response of the detector to shut down in PHWR are in progress.

  17. Development of an inconel self powered neutron detector for in-core reactor monitoring

    International Nuclear Information System (INIS)

    Alex, M.; Ghodgaonkar, M.D.

    2007-01-01

    The paper describes the development and testing of an Inconel600 (2 mm diameterx21 cm long) self-powered neutron detector for in-core neutron monitoring. The detector has 3.5 mm overall diameter and 22 cm length and is integrally coupled to a 12 m long mineral insulated cable. The performance of the detector was compared with cobalt and platinum detectors of similar dimensions. Gamma sensitivity measurements performed at the 60 Co irradiation facility in 14 MR/h gamma field showed values of -4.4x10 -18 A/R/h/cm (-9.3x10 -24 A/γ/cm 2 -s/cm), -5.2x10 -18 A/R/h/cm (-1.133x10 -23 A/γ/cm 2 -s/cm) and 34x10 -18 A/R/h/cm (7.14x10 -23 A/γ/cm 2 -s/cm) for the Inconel, Co and Pt detectors, respectively. The detectors together with a miniature gamma ion chamber and fission chamber were tested in the in-core Apsara Swimming Pool type reactor. The ion chambers were used to estimate the neutron and gamma fields. With an effective neutron cross-section of 4b, the Inconel detector has a total sensitivity of 6x10 -23 A/nv/cm while the corresponding sensitivities for the platinum and cobalt detectors were 1.69x10 -22 and 2.64x10 -22 A/nv/cm. The linearity of the detector responses at power levels ranging from 100 to 200 kW was within ±5%. The response of the detectors to reactor scram showed that the prompt response of the Inconel detector was 0.95 while it was 0.7 and 0.95 for the platinum and cobalt self-powered detectors, respectively. The detector was also installed in the horizontal flux unit of 540 MW Pressurised Heavy Water Reactor (PHWR). The neutron flux at the detector location was calculated by Triveni code. The detector response was measured from 0.02% to 0.07% of full power and showed good correlation between power level and detector signals. Long-term tests and the dynamic response of the detector to shut down in PHWR are in progress

  18. Development of an inconel self powered neutron detector for in-core reactor monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Alex, M. [Electronics Division, BARC, Mumbai (India)]. E-mail: maryalex@barc.gov.in; Ghodgaonkar, M.D. [Electronics Division, BARC, Mumbai (India)

    2007-04-21

    The paper describes the development and testing of an Inconel600 (2 mm diameterx21 cm long) self-powered neutron detector for in-core neutron monitoring. The detector has 3.5 mm overall diameter and 22 cm length and is integrally coupled to a 12 m long mineral insulated cable. The performance of the detector was compared with cobalt and platinum detectors of similar dimensions. Gamma sensitivity measurements performed at the {sup 60}Co irradiation facility in 14 MR/h gamma field showed values of -4.4x10{sup -18} A/R/h/cm (-9.3x10{sup -24} A/{gamma}/cm{sup 2}-s/cm), -5.2x10{sup -18} A/R/h/cm (-1.133x10{sup -23} A/{gamma}/cm{sup 2}-s/cm) and 34x10{sup -18} A/R/h/cm (7.14x10{sup -23} A/{gamma}/cm{sup 2}-s/cm) for the Inconel, Co and Pt detectors, respectively. The detectors together with a miniature gamma ion chamber and fission chamber were tested in the in-core Apsara Swimming Pool type reactor. The ion chambers were used to estimate the neutron and gamma fields. With an effective neutron cross-section of 4b, the Inconel detector has a total sensitivity of 6x10{sup -23} A/nv/cm while the corresponding sensitivities for the platinum and cobalt detectors were 1.69x10{sup -22} and 2.64x10{sup -22} A/nv/cm. The linearity of the detector responses at power levels ranging from 100 to 200 kW was within {+-}5%. The response of the detectors to reactor scram showed that the prompt response of the Inconel detector was 0.95 while it was 0.7 and 0.95 for the platinum and cobalt self-powered detectors, respectively. The detector was also installed in the horizontal flux unit of 540 MW Pressurised Heavy Water Reactor (PHWR). The neutron flux at the detector location was calculated by Triveni code. The detector response was measured from 0.02% to 0.07% of full power and showed good correlation between power level and detector signals. Long-term tests and the dynamic response of the detector to shut down in PHWR are in progress.

  19. Fast Neutron Spectrum Potassium Worth for Space Power Reactor Design Validation

    Energy Technology Data Exchange (ETDEWEB)

    Bess, John D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Marshall, Margaret A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Briggs, J. Blair [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tsiboulia, Anatoli [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rozhikhin, Yevgeniy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mihalczo, John T. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-03-01

    A variety of critical experiments were constructed of enriched uranium metal (oralloy ) during the 1960s and 1970s at the Oak Ridge Critical Experiments Facility (ORCEF) in support of criticality safety operations at the Y-12 Plant. The purposes of these experiments included the evaluation of storage, casting, and handling limits for the Y-12 Plant and providing data for verification of calculation methods and cross-sections for nuclear criticality safety applications. These included solid cylinders of various diameters, annuli of various inner and outer diameters, two and three interacting cylinders of various diameters, and graphite and polyethylene reflected cylinders and annuli. Of the hundreds of delayed critical experiments, one was performed that consisted of uranium metal annuli surrounding a potassium-filled, stainless steel can. The outer diameter of the annuli was approximately 13 inches (33.02 cm) with an inner diameter of 7 inches (17.78 cm). The diameter of the stainless steel can was 7 inches (17.78 cm). The critical height of the configurations was approximately 5.6 inches (14.224 cm). The uranium annulus consisted of multiple stacked rings, each with radial thicknesses of 1 inch (2.54 cm) and varying heights. A companion measurement was performed using empty stainless steel cans; the primary purpose of these experiments was to test the fast neutron cross sections of potassium as it was a candidate for coolant in some early space power reactor designs.The experimental measurements were performed on July 11, 1963, by J. T. Mihalczo and M. S. Wyatt (Ref. 1) with additional information in its corresponding logbook. Unreflected and unmoderated experiments with the same set of highly enriched uranium metal parts were performed at the Oak Ridge Critical Experiments Facility in the 1960s and are evaluated in the International Handbook for Evaluated Criticality Safety Benchmark Experiments (ICSBEP Handbook) with the identifier HEU MET FAST 051. Thin

  20. The use of self-powered neutron detectors (SPN) to measure reactor power

    International Nuclear Information System (INIS)

    Hamidian, M.R.

    1974-01-01

    Due to the complicated design and technical difficulties of the conventional chamber method, neutron flux measurement between fuel rods is not possible. SPN detectors have a very simple design and a small size; therefore, they are suitable for the use inside the space available in the reactor core. The SPN detector consists of an emitter which emits particles by neutron absorption. The particles penetrate in an insulator and reach an outer collector. Among fission products, electrons might be produced by photoeffect or compton effect, internal conversion or pair production which, will also reach the collector. Cobalt and rhodium emitters have found practical application because of their fast response and sensitivity. The (n, γ) reaction in 103 Rh and 60 Co yields several isotopes and isomers which are discussed in the present report

  1. Electrostatic levitation facility optimized for neutron diffraction studies of high temperature liquids at a spallation neutron source

    Energy Technology Data Exchange (ETDEWEB)

    Mauro, N. A., E-mail: namauro@noctrl.edu [Department of Physics, North Central College, Naperville, Illinois 60540 (United States); Vogt, A. J. [Instrument and Source Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Derendorf, K. S. [Mechanical Engineering and Materials Science, Washington University, St. Louis, Missouri 63130 (United States); Johnson, M. L.; Kelton, K. F. [Department of Physics and Institute of Materials Science and Engineering, Washington University, 1 Brookings Drive, St. Louis, Missouri 63130 (United States); Rustan, G. E.; Quirinale, D. G.; Goldman, A. I. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Kreyssig, A. [Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Division of Materials Sciences and Engineering, Ames Laboratory, Ames, Iowa 50011 (United States); Lokshin, K. A. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Neuefeind, J. C.; An, Ke [Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Wang, Xun-Li [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Ave., Kowloon (Hong Kong); Egami, T. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Department of Physics and Astronomy, Joint Institute for Neutron Sciences, University of Tennessee, Knoxville, Tennessee 37996 (United States)

    2016-01-15

    Neutron diffraction studies of metallic liquids provide valuable information about inherent topological and chemical ordering on multiple length scales as well as insight into dynamical processes at the level of a few atoms. However, there exist very few facilities in the world that allow such studies to be made of reactive metallic liquids in a containerless environment, and these are designed for use at reactor-based neutron sources. We present an electrostatic levitation facility, NESL (for Neutron ElectroStatic Levitator), which takes advantage of the enhanced capabilities and increased neutron flux available at spallation neutron sources (SNSs). NESL enables high quality elastic and inelastic neutron scattering experiments to be made of reactive metallic and other liquids in the equilibrium and supercooled temperature regime. The apparatus is comprised of a high vacuum chamber, external and internal neutron collimation optics, and a sample exchange mechanism that allows up to 30 samples to be processed between chamber openings. Two heating lasers allow excellent sample temperature homogeneity, even for samples approaching 500 mg, and an automated temperature control system allows isothermal measurements to be conducted for times approaching 2 h in the liquid state, with variations in the average sample temperature of less than 0.5%. To demonstrate the capabilities of the facility for elastic scattering studies of liquids, a high quality total structure factor for Zr{sub 64}Ni{sub 36} measured slightly above the liquidus temperature is presented from experiments conducted on the nanoscale-ordered materials diffractometer (NOMAD) beam line at the SNS after only 30 min of acquisition time for a small sample (∼100 mg)

  2. Modernization of the High Flux Isotope Reactor (HFIR) to Provide a Cold Neutron Source and Experimentation Facility

    International Nuclear Information System (INIS)

    Rothrock, Benjamin G.; Farrar, Mike B.

    2009-01-01

    In June 1961, construction was started on the High Flux Isotope Reactor (HFIR) facility inside the Oak Ridge National Laboratory (ORNL), at the recommendation of the U.S. Atomic Energy Commission (AEC) Division of Research. Construction was completed in early 1965 with criticality achieved on August 25, 19651. From the first full power operating cycle beginning in September 1966, the HFIR has achieved an outstanding record of service to the scientific community. In early 1995, the ORNL deputy director formed a group to examine the need for upgrades to the HFIR following the cancellation of the Advanced Neutron Source Project by DOE. This group indicated that there was an immediate need for the installation of a cold neutron source facility in the HFIR to produce cold neutrons for neutron scattering research uses. Cold neutrons have long wavelengths in the range of 4-12 angstroms. Cold neutrons are ideal for research applications with long length-scale molecular structures such as polymers, nanophase materials, and biological samples. These materials require large scale examination (and therefore require a longer wavelength neutron). These materials represent particular areas of science are at the forefront of current research initiatives that have a potentially significant impact on the materials we use in our everyday lives and our knowledge of biology and medicine. This paper discusses the installation of a cold neutron source at HFIR with respect to the project as a modernization of the facility. The paper focuses on why the project was required, the scope of the cold source project with specific emphasis on the design, and project management information.

  3. Development of a high efficient conventional type cold neutron source using a non-explosive material

    International Nuclear Information System (INIS)

    Kiyanagi, Y.; Satoh, S.

    1999-01-01

    An efficient cold moderator that can be used easily at a small neutron source would be useful for neutron radiography, prompt gamma ray analysis and so on. Non-explosive materials are chosen for a cold moderator since explosive materials such as hydrogen and methane require a safety system. Neutronic performances of coupled moderators of various non-explosive materials are studied so as to develop such a cold moderator since the coupled moderator system is the best to obtain high intensity of cold neutrons. Effect of premoderator is studied and neutron spectra from methanol, ethanol, benzene, mesitylene and benzene methanol are measured around 20 K. The premoderator increased the cold neutron intensity by about 50∼70%. Methanol and mesitylene gave the highest cold neutron intensity. Effect of Be filter-reflector is also studied and a intensity gain of about 20% was obtained below about 5 MeV. (author)

  4. Non-equilibrium thermodynamics of highly rarefied neutron gas under creative and destructive reactions

    International Nuclear Information System (INIS)

    Hayasaka, Hideo

    1978-01-01

    The thermodynamic structures of non-equilibrium steady states of a highly rarefied neutron gas in various media are considered in terms of the irreversible processes due to creative and destructive reactions of neutrons with nuclei of these media and to neutrons supplied from external sources. The respective subsystems of the stationary neutron gas are regarded as imperfect equilibrium systems in the presence of the medium and the external neutron sources, and are treated like different species in a mixture. The entropy production due to neutron-nuclear reactions has a minimum value at the steady state. The distribution function of such a neutron gas is determined from the extremum condition in which entropy does not change, and is expressed as a shifted Boltzmann distribution specified by the respective values of the generalized chemical potential for each energy level. (author)

  5. Superconducting high frequency high power resonators

    International Nuclear Information System (INIS)

    Hobbis, C.; Vardiman, R.; Weinman, L.

    1974-01-01

    A niobium superconducting quarter-wave helical resonator has been designed and built. The resonator has been electron-beam welded and electropolished to produce a smooth flaw-free surface. This has been followed by an anodization to produce a 1000 A layer of Nb 2 0 5 . At the resonant frequency of approximately 15 MHz the unloaded Q was approximately equal to 4.6x10 6 with minimal dielectric support. With the resonator open to the helium bath to provide cooling, and rigidly supported by a teflon cylinder, 350 V of power were transferred at a doubly loaded Q of 3500. The extrapolation of the results to a Qsub(DL) of 1000 meet the power handling criteria of one kilowatt for the intended application. (author)

  6. The low power miniature neutron source reactors: Design, safety and applications

    International Nuclear Information System (INIS)

    Ahmed, Y.A.; Ewa, I.O.B.; Umar, M.; Bezboruah, T.; Johri, M.; Akaho, E.H.K.

    2006-04-01

    The Chinese Miniature Neutron Source Reactor (MNSR) is a low power research reactor with maximum thermal neutron flux of 1 x 10 12 n.cm -2 .s -1 in one of its inner irradiation channels and thermal power of approximately 30kW. The MNSR is designed based on the Canadian SLOWPOKE reactor and is one of the smallest commercial research reactors presently available in the world. Its commercial versions currently in operation in China, Ghana, Iran, Nigeria, Pakistan and Syria, is considered as an excellent tool for Neutron Activation Analysis (NAA), training of Scientist, and Engineers in nuclear science and technology and small scale radioisotope production. The paper highlights the basic design and theory of the commercial MNSR, its safety features, applications and advantages over the Chinese Prototype. The experimental flux characteristics determined in this work and in similar studies by other authors reveal that the commercial MNSR has more flux stability, longer life span, higher negative temperature coefficient of reactivity and low under-moderation compared to its prototype in China. The result shows that the facility is safe for reactor physics experiments, teaching and training of students and also ideal for application of NAA for the determination of elemental composition of biological and environmental samples. It can also be a useful tool for geochemical and soil fertility mapping. (author)

  7. Assessment of the Neutronic and Fuel Cycle Performance of the Transatomic Power Molten Salt Reactor Design

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Sean [Transatomic Power Corp., Cambridge, MA (United States); Dewan, Leslie [Transatomic Power Corp., Cambridge, MA (United States); Massie, Mark [Transatomic Power Corp., Cambridge, MA (United States); Davidson, Eva E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Betzler, Benjamin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Worrall, Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Powers, Jeffrey J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    This report presents results from a collaboration between Transatomic Power Corporation (TAP) and Oak Ridge National Laboratory (ORNL) to provide neutronic and fuel cycle analysis of the TAP core design through the Department of Energy Gateway for Accelerated Innovation in Nuclear (GAIN) Nuclear Energy Voucher program. The TAP concept is a molten salt reactor using configurable zirconium hydride moderator rod assemblies to shift the neutron spectrum in the core from mostly epithermal at beginning of life to thermal at end of life. Additional developments in the ChemTriton modeling and simulation tool provide the critical moderator-to-fuel ratio searches and time-dependent parameters necessary to simulate the continuously changing physics in this complex system. The implementation of continuous-energy Monte Carlo transport and depletion tools in ChemTriton provide for full-core three-dimensional modeling and simulation. Results from simulations with these tools show agreement with TAP-calculated performance metrics for core lifetime, discharge burnup, and salt volume fraction, verifying the viability of reducing actinide waste production with this concept. Additional analyses of mass feed rates and enrichments, isotopic removals, tritium generation, core power distribution, core vessel helium generation, moderator rod heat deposition, and reactivity coeffcients provide additional information to make informed design decisions. This work demonstrates capabilities of ORNL modeling and simulation tools for neutronic and fuel cycle analysis of molten salt reactor concepts.

  8. High resolution fast neutron spectrometry without time-of-flight

    International Nuclear Information System (INIS)

    Evans, A.E.; Brandenberger, J.D.

    1978-01-01

    Performance tests of a spectrometer tube of the type developed by Cuttler and Shalev show that the measurement of fast neutron spectra with this device can be made with an energy resolution previously obtainable only in large time-of-flight facilities. In preliminary tests, resolutions of 16.4 keV for thermal neutrons and 30.9 keV for 1-MeV neutrons were obtained. A broad-window pulse-shape discrimination (PSD) system is used to remove from pulse-height distributions most of the continua due to 3 He-recoil events, noise, and wall effect. Use of PSD improved the energy resolution to 12.9 keV for thermal neutrons and 29.2 keV for 1-MeV neutrons. The detector is a viable tool for neutron research at nominally equipped accelerator laboratories

  9. Forward angle quasi-free proton-neutron analyzing powers at 0.8 GeV

    International Nuclear Information System (INIS)

    Barlett, M.L.

    1981-01-01

    As the first step in determining the nucleon-nucleon scattering amplitudes at small momentum transfers at 0.8 GeV, quasi-free p vector + n and p vector + p analyzing powers were obtained at laboratory scattering angles from 6 0 to 32.9 0 by scattering 800-MeV polarized protons from a liquid deuterium target. Forward-scattered protons were detected by the High Resolution Spectrometer (HRS), while recoil neutrons and protons were detected in coincidence with the event detected with the HRS by a 5 x 5 array of scintillators. A thin scintillator placed between the target and the array enabled discrimination of recoil particle type and facilitated the simultaneous measurement of both p vector n and n vector p analyzing powers. A comparison of the results with previously measured free p vector p and n vector p analyzing powers shows excellent agreement between the free and quasi-free p vector p analyzing powers. Poorer agreement is seen for the p vector n analyzing powers. The results of phase-shift analyses are presented in order to study the effects of the quasi-free analyzing power measurements on the determination of the pn scattering amplitudes. Amplitudes obtained from the phase-shift analyses are then used in KMT calculations. The results indicate that further nucleon-nucleon measurements are necessary in order to determine the nucleon-nucleon amplitudes unambiguously at 800 MeV

  10. High-Resolution Fast-Neutron Spectrometry for Arms Control and Treaty Verification

    Energy Technology Data Exchange (ETDEWEB)

    David L. Chichester; James T. Johnson; Edward H. Seabury

    2012-07-01

    Many nondestructive nuclear analysis techniques have been developed to support the measurement needs of arms control and treaty verification, including gross photon and neutron counting, low- and high-resolution gamma spectrometry, time-correlated neutron measurements, and photon and neutron imaging. One notable measurement technique that has not been extensively studied to date for these applications is high-resolution fast-neutron spectrometry (HRFNS). Applied for arms control and treaty verification, HRFNS has the potential to serve as a complimentary measurement approach to these other techniques by providing a means to either qualitatively or quantitatively determine the composition and thickness of non-nuclear materials surrounding neutron-emitting materials. The technique uses the normally-occurring neutrons present in arms control and treaty verification objects of interest as an internal source of neutrons for performing active-interrogation transmission measurements. Most low-Z nuclei of interest for arms control and treaty verification, including 9Be, 12C, 14N, and 16O, possess fast-neutron resonance features in their absorption cross sections in the 0.5- to 5-MeV energy range. Measuring the selective removal of source neutrons over this energy range, assuming for example a fission-spectrum starting distribution, may be used to estimate the stoichiometric composition of intervening materials between the neutron source and detector. At a simpler level, determination of the emitted fast-neutron spectrum may be used for fingerprinting 'known' assemblies for later use in template-matching tests. As with photon spectrometry, automated analysis of fast-neutron spectra may be performed to support decision making and reporting systems protected behind information barriers. This paper will report recent work at Idaho National Laboratory to explore the feasibility of using HRFNS for arms control and treaty verification applications, including simulations

  11. High-resolution neutron spectroscopy on protein solution samples

    International Nuclear Information System (INIS)

    Grimaldo, M.; Henning, M.; Roosen-Runge, F.; Seydel, T.; Jalarvo, N.; Zamponi, M.; Zanini, F.; Zhang, F.; Schreiber, F.

    2015-01-01

    Proteins in solution are subject to a complex superposition of global translational and rotational diffusion as well as internal relaxations covering a wide range of time scales. With the advent of new high-flux neutron spectrometers in combination with enhanced analysis frameworks it has become possible to separate these different contributions. We discuss new approaches to the analysis by presenting example spectra and fits from data recorded on the backscattering spectrometers IN16, IN16B, and BASIS on the same protein solution sample. We illustrate the separation of the rotational and translational diffusion contribution, the accurate treatment of the solvent contribution, and the extraction of information on internal fluctuations. We also highlight the progress made in passing from second- to third-generation backscattering spectrometers. (authors)

  12. High energy neutron dosimetry for the fusion program

    International Nuclear Information System (INIS)

    Barr, D.W.; Norris, A.E.

    1977-01-01

    Neutron dosimetry by the foil activation method offers a flexible technique for characterizing neutron spectra ranging from thermal energies to 30 MeV with the potential for extension to higher neutron energies as investigated by the Los Alamos Radiochemistry Group at the Los Alamos Meson Physics Facility and in the Apollo-Soyuz Test Project. The use of this method for the neutron flux description in thermal, resonance, and fission spectrum assemblies has been demonstrated. An extension of the method to environments involving thermonuclear processes was developed at Los Alamos in the early 1950's to characterize mixed fission-thermonuclear systems

  13. Neutron activation analysis of high pure uranium using preconcentration

    International Nuclear Information System (INIS)

    Sadikov, I.I.; Rakhimov, A.V.; Salimov, M.I.; Zinov'ev, V.G.

    2006-01-01

    Full text: Uranium and its compounds are used as nuclear fuel, and requirements for purity of initial uranium are very high. Therefore highly sensitive and multielemental analysis of uranium is required. One of such methods is neutron activation analysis (NAA). During irradiation of uranium by nuclear reactor neutrons the induced radioactivity of a sample is formed by uranium radionuclide 239 U (T 1/2 = 23,4 min.) and its daughter radionuclide 239 Np (T 1/2 = 2,39 d). Short-lived 239 U almost completely decays in 24 hours after irradiation and the radioactivity of the sample is mainly due to 239 Np and is more than 10 9 Bq for 0.1 g of uranium sample (F = 1*10 14 cm -2 s -1 , t irr . = 5 h). That is why nondestructive determination of the impurities is impossible and they should be separated from 239 Np. When irradiated uranium yields fission products - radionuclides of some elements with mass numbers 91-104 and 131-144. The main problem in NAA of uranium is to take into account correctly the influence of fission products on the analysis results. We have developed a radiochemical separation procedure for RNAA of uranium [1]. Comparing the results of analysis carried out by radiochemical NAA and instrumental NAA with preconcentration of trace elements can be used for evaluating the interference of fission products on uranium analysis results. Preconcentration of trace elements have been carried out by extraction chromatography in 'TBP - 6M HNO 3 ' system [1]. Experiments have shown that if 0.1 g uranium sample is taken for analysis (F = 1*10 14 cm -2 s -1 , t irr . =5 h) the apparent concentration of Y, Zr, Mo, Cs, La, Ce, Pr, Nd exceeds the true concentration by 2500-3000 times and so determination of these elements is not possible by radiochemical NAA. (author)

  14. Gravitational Waves from F-modes Excited by the Inspiral of Highly Eccentric Neutron Star Binaries

    International Nuclear Information System (INIS)

    Chirenti, Cecilia; Gold, Roman; Miller, M. Coleman

    2017-01-01

    As gravitational wave instrumentation becomes more sensitive, it is interesting to speculate about subtle effects that could be analyzed using upcoming generations of detectors. One such effect that has great potential for revealing the properties of very dense matter is fluid oscillations of neutron stars. These have been found in numerical simulations of the hypermassive remnants of double neutron star mergers and of highly eccentric neutron star orbits. Here we focus on the latter and sketch out some ideas for the production, gravitational-wave detection, and analysis of neutron star oscillations. These events will be rare (perhaps up to several tens per year could be detected using third-generation detectors such as the Einstein Telescope or the Cosmic Explorer), but they would have unique diagnostic power for the analysis of cold, catalyzed, dense matter. Furthermore, these systems are unusual in that analysis of the tidally excited f-modes of the stars could yield simultaneous measurements of their masses, moments of inertia, and tidal Love numbers, using the frequency, damping time, and amplitude of the modes. They would thus present a nearly unique opportunity to test the I-Love-Q relation observationally. The analysis of such events will require significant further work in nuclear physics and general relativistic nonlinear mode coupling, and thus we discuss further directions that will need to be pursued. For example, we note that for nearly grazing encounters, numerical simulations show that the energy delivered to the f-modes may be up to two orders of magnitude greater than predicted in the linear theory.

  15. Gravitational Waves from F-modes Excited by the Inspiral of Highly Eccentric Neutron Star Binaries

    Energy Technology Data Exchange (ETDEWEB)

    Chirenti, Cecilia [Centro de Matemática, Computação e Cognição, UFABC, 09210-170 Santo André-SP (Brazil); Gold, Roman [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada); Miller, M. Coleman [Department of Astronomy and Joint Space-Science Institute, University of Maryland, College Park, MD 20742-2421 (United States)

    2017-03-01

    As gravitational wave instrumentation becomes more sensitive, it is interesting to speculate about subtle effects that could be analyzed using upcoming generations of detectors. One such effect that has great potential for revealing the properties of very dense matter is fluid oscillations of neutron stars. These have been found in numerical simulations of the hypermassive remnants of double neutron star mergers and of highly eccentric neutron star orbits. Here we focus on the latter and sketch out some ideas for the production, gravitational-wave detection, and analysis of neutron star oscillations. These events will be rare (perhaps up to several tens per year could be detected using third-generation detectors such as the Einstein Telescope or the Cosmic Explorer), but they would have unique diagnostic power for the analysis of cold, catalyzed, dense matter. Furthermore, these systems are unusual in that analysis of the tidally excited f-modes of the stars could yield simultaneous measurements of their masses, moments of inertia, and tidal Love numbers, using the frequency, damping time, and amplitude of the modes. They would thus present a nearly unique opportunity to test the I-Love-Q relation observationally. The analysis of such events will require significant further work in nuclear physics and general relativistic nonlinear mode coupling, and thus we discuss further directions that will need to be pursued. For example, we note that for nearly grazing encounters, numerical simulations show that the energy delivered to the f-modes may be up to two orders of magnitude greater than predicted in the linear theory.

  16. Low energy nuclear spin excitations in Ho metal investigated by high resolution neutron spectroscopy.

    Science.gov (United States)

    Chatterji, Tapan; Jalarvo, Niina

    2013-04-17

    We have investigated the low energy excitations in metallic Ho by high resolution neutron spectroscopy. We found at T = 3 K clear inelastic peaks in the energy loss and energy gain sides, along with the central elastic peak. The energy of this low energy excitation, which is 26.59 ± 0.02 μeV at T = 3 K, decreased continuously and became zero at TN ≈ 130 K. By fitting the data in the temperature range 100-127.5 K with a power law we obtained the power-law exponent β = 0.37 ± 0.02, which agrees with the expected value β = 0.367 for a three-dimensional Heisenberg model. Thus the energy of the low energy excitations can be associated with the order parameter.

  17. The Idaho Power Burst Facility/Boron Neutron Capture Therapy (PBF/BNCT) Program overview

    International Nuclear Information System (INIS)

    Dorn, R.V. III; Griebenow, M.L.; Ackermann, A.L.; Miller, L.G.; Miller, D.L.; Wheeler, F.J.; Bradshaw, K.M.; Wessol, D.E.; Harker, Y.D.; Nigg, D.W.; Randolph, P.D.; Bauer, W.F.; Gavin, P.R.; Richards, T.L.

    1992-01-01

    The Power Burst Facility/Boron Neutron Capture Therapy (PBF/BNCT) Program has been funded since 1988 to evaluate brain tumor treatment using Na 2 B 12 H 11 SH (borocaptate sodium or BSH) and epithermal neutrons. The PBF/BNCT Program pursues this goal as a comprehensive, multidisciplinary, multiorganizational endeavor applying modern program management techniques. The initial focus was to: (1) establish a representative large animal model and (2) develop the generic analytical and measurement capabilities require to control treatment repeatability and determine critical treatment parameters independent of tumor type and body location. This paper will identify the PBF/BNCT Program elements and summarize the status of some of the developed capabilities

  18. How to polarise all neutrons in one beam: a high performance polariser and neutron transport system

    Science.gov (United States)

    Rodriguez, D. Martin; Bentley, P. M.; Pappas, C.

    2016-09-01

    Polarised neutron beams are used in disciplines as diverse as magnetism,soft matter or biology. However, most of these applications often suffer from low flux also because the existing neutron polarising methods imply the filtering of one of the spin states, with a transmission of 50% at maximum. With the purpose of using all neutrons that are usually discarded, we propose a system that splits them according to their polarisation, flips them to match the spin direction, and then focuses them at the sample. Monte Carlo (MC) simulations show that this is achievable over a wide wavelength range and with an outstanding performance at the price of a more divergent neutron beam at the sample position.

  19. Neutronic characteristics of FLWR in the transition phase changing from high conversion core to breeder core

    International Nuclear Information System (INIS)

    Akie, Hiroshi; Nakano, Yoshihiro; Okubo, Tsutomu

    2009-01-01

    Innovative Water Reactor for Flexible Fuel Cycle (FLWR) is a low moderation type boiling water reactor which can realize plutonium multiple recycling and breeding. For the introduction stage of FLWR, a high conversion (HC) type FLWR is proposed to keep technical continuity from current light water reactors. The HC core of FLWR has a less tight fuel lattice with lower coolant void fraction than the breeder (BR) type core. The HC type FLWR core is to be shifted to the BR core by only replacing the fuel assemblies of the same outer shape and size in the same reactor system. In the HC to BR transition phase of FLWR, there exist both types of fuel assemblies in the same core configuration. In the HC assembly, neutron spectrum is softer than in the BR assembly, and the axial fuel and blanket arrangement is different from the BR assembly. Due to these differences, there might appear a power peaking in the adjacent region between HC and BR assemblies. The power distribution in the HC + BR assemblies mixed core configuration is studied by performing assembly calculations and core calculations on a few assemblies local geometry and the whole core geometry. As a result, although a power peaking can be locally very large in the HC and BR assemblies adjacent regions, such local power peakings are shown to be effectively reduced by considering a rod-wise fuel enrichment distribution. In the whole core calculation, it seems possible to optimize the fuel assembly loading and shuffling pattern to avoid large power level mismatch between the assemblies. It is expected that FLWR can be shifted from HC type to BR type without major neutronic difficulties. (author)

  20. Discovery of a Highly Relativistic Double Neutron Star Binary

    Science.gov (United States)

    Chatterjee, Shami; Stovall, Kevin; PALFA Collaboration, Paul Demorest, Nihan Pol

    2018-01-01

    We report the discovery of a double neutron star (DNS) binary system, PSR J1946+2052, in Arecibo L-Band Feed Array Pulsar Survey (PALFA) observations. PSR J1946+2052 is a 17-ms pulsar in a 1.88-hour, eccentric (e = 0.06) orbit with a 1.2 solar mass companion. We have localized the pulsar to a precision of 0.09 arcseconds using a new phase binning mode at the Jansky Very Large Array. The improved position has enabled a measurement of the pulsar spin period derivative of 9E-19 s/s; the low inferred magnetic field strength at the surface of 4E+9 Gauss indicates that the pulsar has been recycled. Among all known DNS systems, PSR J1946+2052 has the shortest orbital period, and currently radiates ~13% of a solar luminosity in gravitational wave power. Its estimated time to merger is only 45.5 MYr, the shortest known, and at that time it will display the largest spin effects of any such system discovered to date. We have also measured the advance of periastron passage for this system, 25.6 +/- 0.3 degrees per year, resulting in a total system mass measurement of 2.50 +/- 0.04 solar masses.

  1. Three new nondestructive evaluation tools based on high flux neutron sources

    International Nuclear Information System (INIS)

    Hubbard, C.R.; Raine, D.; Peascoe, R.; Wright, M.

    1997-01-01

    Nondestructive evaluation methods and systems based on specific attributes of neutron interactions with materials are being developed. The special attributes of neutrons are low attenuation in most engineering materials, strong interaction with low Z elements, and epithermal neutron absorption resonances. The three methods under development at ORNL include neutron based tomography and radiography; through thickness, nondestructive texture mapping; and internal, noninvasive temperature measurement. All three techniques require high flux sources such as the High Flux Isotope Reactor, a steady state source, or the Oak Ridge Electron Linear Accelerator, a pulsed neutron source. Neutrons are quite penetrating in most engineering materials and thus can be useful to detect internal flaws and features. Hydrogen atoms, such as in a hydrocarbon fuel, lubricant, or a metal hydride, are relatively opaque to neutron transmission and thus neutron based tomography/radiography is ideal to image their presence. Texture, the nonrandom orientation of crystalline grains within materials, can be mapped nondestructively using neutron diffraction methods. Epithermal neutron resonance absorption is being studied as a noncontacting temperature sensor. This paper highlights the underlying physics of the methods, progress in development, and the potential benefits for science and industry of the three facilities

  2. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    International Nuclear Information System (INIS)

    Brunckhorst, Elin

    2009-01-01

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a 10 B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with 6 Li and 7 Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined with an

  3. Experimental investigations of the neutron contamination in high-energy photon fields at medical linear accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Brunckhorst, Elin

    2009-02-26

    The scope of this thesis was to develop a device for the detection of the photoneutron dose inside the high-energy photon field. The photoneutron contamination of a Siemens PRIMUS linear accelerator was investigated in detail in its 15 MV photon mode. The experimental examinations were performed with three ionisation chambers (a tissue equivalent chamber, a magnesium chamber and a {sup 10}B-coated magnesium chamber) and two types of thermoluminescence detectors (enriched with {sup 6}Li and {sup 7}Li, respectively). The detectors have different sensitivities to photons and neutrons and their combination allows the dose separation in a mixed neutron/photon field. The application of the ionisation chamber system, as well as the present TLD system for photoneutron detection in high-energy photon beams is a new approach. The TLD neutron sensitivity was found to be too low for a measurement inside the open photon field and the further investigation focused on the ionisation chambers. The three ionisation chambers were calibrated at different photon and neutron sources and a the borated magnesium chamber showed a very high response to thermal neutrons. For a cross check of the calibration, the three chambers were also used for dose separation of a boron neutron capture therapy beam where the exact determination of the thermal neutron dose is essential. Very accurate results were achieved for the thermal neutron dose component. At the linear accelerator the chamber system was reduced to a paired chamber system utilising the two magnesium chambers, since the fast neutron component was to small to be separated. The neutron calibration of the three chambers could not be applied, instead a conversion of measured thermal neutron signal by the borated chamber to Monte Carlo simulated total neutron dose was performed. Measurements for open fields in solid water and liquid water were performed with the paired chamber system. In larger depths the neutron dose could be determined

  4. Automated System Tests High-Power MOSFET's

    Science.gov (United States)

    Huston, Steven W.; Wendt, Isabel O.

    1994-01-01

    Computer-controlled system tests metal-oxide/semiconductor field-effect transistors (MOSFET's) at high voltages and currents. Measures seven parameters characterizing performance of MOSFET, with view toward obtaining early indication MOSFET defective. Use of test system prior to installation of power MOSFET in high-power circuit saves time and money.

  5. Synergies Between ' and Cavity Formation in HT-9 Following High Dose Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parish, Chad M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Saleh, Tarik A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eftink, Benjamin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Candidate cladding materials for advanced nuclear power reactors including fast reactor designs require materials capable of withstanding high dose neutron irradiation at elevated temperatures. One candidate material, HT-9, through various research programs have demonstrated the ability to withstand significant swelling and other radiation-induced degradation mechanisms in the high dose regime (>50 displacements per atom, dpa) at elevated temperatures (>300 C). Here, high efficiency multi-dimensional scanning transmission electron microscopy (STEM) acquisition with the aid of a three-dimensional (3D) reconstruction and modeling technique is used to probe the microstructural features that contribute to the exceptional swelling resistance of HT-9. In particular, the synergies between ' and fine-scale and moderate-scale cavity formation is investigated.

  6. A high-resolution neutron spectra unfolding method using the Genetic Algorithm technique

    CERN Document Server

    Mukherjee, B

    2002-01-01

    The Bonner sphere spectrometers (BSS) are commonly used to determine the neutron spectra within various nuclear facilities. Sophisticated mathematical tools are used to unfold the neutron energy distribution from the output data of the BSS. This paper highlights a novel high-resolution neutron spectra-unfolding method using the Genetic Algorithm (GA) technique. The GA imitates the biological evolution process prevailing in the nature to solve complex optimisation problems. The GA method was utilised to evaluate the neutron energy distribution, average energy, fluence and equivalent dose rates at important work places of a DIDO class research reactor and a high-energy superconducting heavy ion cyclotron. The spectrometer was calibrated with a sup 2 sup 4 sup 1 Am/Be (alpha,n) neutron standard source. The results of the GA method agreed satisfactorily with the results obtained by using the well-known BUNKI neutron spectra unfolding code.

  7. Spatial distribution of moderated neutrons along a Pb target irradiated by high-energy protons

    International Nuclear Information System (INIS)

    Fragopoulou, M.; Manolopoulou, M.; Stoulos, S.; Brandt, R.; Westmeier, W.; Kulakov, B.A.; Krivopustov, M.I.; Sosnin, A.N.; Debeauvais, M.; Adloff, J.C.; Zamani Valasiadou, M.

    2006-01-01

    High-energy protons in the range of 0.5-7.4 GeV have irradiated an extended Pb target covered with a paraffin moderator. The moderator was used in order to shift the hard Pb spallation neutron spectrum to lower energies and to increase the transmutation efficiency via (n,γ) reactions. Neutron distributions along and inside the paraffin moderator were measured. An analysis of the experimental results was performed based on particle production by high-energy interactions with heavy targets and neutron spectrum shifting by the paraffin. Conclusions about the spallation neutron production in the target and moderation through the paraffin are presented. The study of the total neutron fluence on the moderator surface as a function of the proton beam energy shows that neutron cost is improved up to 1 GeV. For higher proton beam energies it remains constant with a tendency to decline

  8. Rhodium self-powered neutron detector's lifetime for korean standard nuclear power plants

    International Nuclear Information System (INIS)

    Yoo, Choon Sung; Kim, Byoung Chul; Park, Jong Ho; Fero, Arnold H.; Anderson, S. L.

    2005-01-01

    A method to estimate the relative sensitivity of a self-powered rhodium detector for an upcoming cycle is developed by combining the rhodium depletion data from a nuclear design with the site measurement data. This method can be used both by nuclear power plant designers and by site staffs of Korean standard nuclear power plants for determining which rhodium detectors should be replaced during overhauls

  9. Use of higher order signal moments and high speed digital sampling technique for neutron flux measurements

    Science.gov (United States)

    Baers, L. B.; Gutierrez, T. Rivero; Mendoza, R. A. Carrillo; Santana, G. Jimenez

    1993-08-01

    The second (conventional variance or Campbell signal), the third, and the modified fourth order central signal moments associated with the amplified and filtered currents from two electrodes of an ex-core neutron sensitive fission detector were measured versus the reactor power of the 1-MW TRIGA reactor in Mexico City. Two channels of a high-speed (400-MHz) multiplexing data sampler and an analog-to-digital converter with 12-b resolution and 1-Mword buffer memory were used. The data were further retrieved into a PC, and estimates for autocorrelation and cross-correlation moments up to the fifth order, coherence, skewness, excess, etc., quantities were calculated offline. Five-mode operation of the detector was achieved, including conventional counting rates and currents in agreement with theory and the authors' previous results with analog techniques. The signals are proportional to the neutron flux and reactor power in some flux ranges. The suppression of background noise is improved and the lower limit of the measurement range is extended as the order of moment is increased, in agreement with theory.

  10. Demonstration of a high-intensity neutron source based on a liquid-lithium target for Accelerator based Boron Neutron Capture Therapy.

    Science.gov (United States)

    Halfon, S; Arenshtam, A; Kijel, D; Paul, M; Weissman, L; Berkovits, D; Eliyahu, I; Feinberg, G; Kreisel, A; Mardor, I; Shimel, G; Shor, A; Silverman, I; Tessler, M

    2015-12-01

    A free surface liquid-lithium jet target is operating routinely at Soreq Applied Research Accelerator Facility (SARAF), bombarded with a ~1.91 MeV, ~1.2 mA continuous-wave narrow proton beam. The experiments demonstrate the liquid lithium target (LiLiT) capability to constitute an intense source of epithermal neutrons, for Accelerator based Boron Neutron Capture Therapy (BNCT). The target dissipates extremely high ion beam power densities (>3 kW/cm(2), >0.5 MW/cm(3)) for long periods of time, while maintaining stable conditions and localized residual activity. LiLiT generates ~3×10(10) n/s, which is more than one order of magnitude larger than conventional (7)Li(p,n)-based near threshold neutron sources. A shield and moderator assembly for BNCT, with LiLiT irradiated with protons at 1.91 MeV, was designed based on Monte Carlo (MCNP) simulations of BNCT-doses produced in a phantom. According to these simulations it was found that a ~15 mA near threshold proton current will apply the therapeutic doses in ~1h treatment duration. According to our present results, such high current beams can be dissipated in a liquid-lithium target, hence the target design is readily applicable for accelerator-based BNCT. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Space nuclear-power reactor design based on combined neutronic and thermal-fluid analyses

    International Nuclear Information System (INIS)

    Koenig, D.R.; Gido, R.G.; Brandon, D.I.

    1985-01-01

    The design and performance analysis of a space nuclear-power system requires sophisticated analytical capabilities such as those developed during the nuclear rocket propulsion (Rover) program. In particular, optimizing the size of a space nuclear reactor for a given power level requires satisfying the conflicting requirements of nuclear criticality and heat removal. The optimization involves the determination of the coolant void (volume) fraction for which the reactor diameter is a minimum and temperature and structural limits are satisfied. A minimum exists because the critical diameter increases with increasing void fraction, whereas the reactor diameter needed to remove a specified power decreases with void fraction. The purpose of this presentation is to describe and demonstrate our analytical capability for the determination of minimum reactor size. The analysis is based on combining neutronic criticality calculations with OPTION-code thermal-fluid calculations

  12. A deuteron linac for a high-intensity neutron source

    International Nuclear Information System (INIS)

    Staples, J.; Clark, D.; Grunder, H.; Lancaster, H.; Main, R.; Selph, F.; Smith, L.; Voelker, F.; Yourd, R.

    1976-01-01

    The preliminary design of an accelerator suitable to meet the flux and neutron energy requirements of a CTR materials test facility is presented. The specifications of such a facility call for a neutron flux of 10 14 n/cm 2 -sec distributed over an area of about 10 2 cm 2 with a neutron spectrum similar to that anticipated from a fusion reactor. A 30 MeV deuteron linac producing a CW beam of 125 mA, upgradable to 40 MeV at 250 mA at a later date, would produce the relatively broad spectrum of neutrons at the required intensity. Attention to the low-energy beam intercept on the drift tubes and diffusive losses producing neutrons and attendant activation problems are discussed

  13. Relativistic polarized neutrons at the Laboratory of High Energy Physics, JINR

    International Nuclear Information System (INIS)

    Kirillov, A.; Komolov, L.; Kovalenko, A.; Matyushevskij, E.; Nomofilov, A.; Rukoyatkin, P.; Sharov, V.; Starikov, A.; Strunov, L.; Svetov, A.

    1996-01-01

    Using slowly extracted polarized deuterons, available at the accelerator facility of the Laboratory of High Energy Physics, JINR, polarized quasi-monochromatic neutrons with momenta from 1.1 to 4.5 GeV/c have been generated. Depending on momentum, from 10 4 to 10 6 polarized neutrons per accelerator cycle were produced. At present, the polarized neutrons are mainly intended for measuring the (n vec, p vec) total cross section differences. 6 refs., 2 figs

  14. Design of a fuzzy logic based controller for neutron power regulation

    International Nuclear Information System (INIS)

    Velez D, D.

    2000-01-01

    This work presents a fuzzy logic controller design for neutron power control, from its source to its full power level, applied to a nuclear reactor model. First, we present the basic definitions on fuzzy sets as generalized definitions of the crisp (non fuzzy) set theory. Likewise, we define the basic operations on fuzzy sets (complement, union, and intersection), and the operations on fuzzy relations such as projection and cylindrical extension operations. Furthermore, some concepts of the fuzzy control theory, such as the main modules of the typical fuzzy controller structure and its internal variables, are defined. After the knowledge base is obtained by simulation of the reactor behavior, where the controlled system is modeled by a simple nonlinear reactor model, this model is used to infer a set of fuzzy rules for the reactor response to different insertions of reactivity. The reduction of the response time, using fuzzy rule based controllers on this reactor, is possible by adjusting the output membership functions, by selecting fuzzy rule sets, or by increasing the number of crisp inputs to the fuzzy controller. System characteristics, such as number of rules, response times, and safety parameter values, were considered in the evaluation of each controller merits. Different fuzzy controllers are designed to attain the desired power level, to maintain a constant level for long periods of time, and to keep the reactor away from a shutdown condition. The basic differences among the controllers are the number of crisp inputs and the novel implementation of a crisp power level-based selection of different sets of output membership functions. Simulation results highlight, mainly: (1) A decrease of the response variations at low power level, and (2) a decrease in the time required to attain the desired neutron power. Finally, we present a comparative study of different fuzzy control algorithms applied to a nuclear model. (Author)

  15. Ultra-High Field Magnets for X-Ray and Neutron Scattering using High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Winn, Barry L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Broholm, C. [Johns Hopkins Univ., Baltimore, MD (United States); Bird, M. [Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab); Breneman, Bruce C. [General Atomics, San Diego, CA (United States); Coffey, Michael [Cryomagnetics, Oak Ridge, TN (United States); Cutler, Roy I. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Duckworth, Robert C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Erwin, R. [National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Hahn, Seungyong [Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab); Hernandez, Yamali [National Inst. of Standards and Technology (NIST), Gaithersburg, MD (United States); Herwig, Kenneth W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holland, Leo D. [General Atomics, San Diego, CA (United States); Lonergan, Kevin M. [Oxford Instruments, Abingdon (United Kingdom); Melhem, Ziad [Oxford Instruments, Abingdon (United Kingdom); Minter, Stephen J. [Cryomagnetics, Oak Ridge, TN (United States); Nelson, C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Paranthaman, M. Parans [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pierce, Josh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ruff, Jacob [Cornell Univ., Ithaca, NY (United States); Shen, Tengming [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherline, Todd E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smeibidl, Peter G. [Helmholtz-Zentrum Berlin (HZB), (Germany); Tennant, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); van der Laan, Danko [Advanced Conductor Technologies, LLC, Boulder, CO (United States); Wahle, Robert J. [Helmholtz-Zentrum Berlin (HZB), (Germany); Zhang, Yifei [SuperPower, Inc., Schenectady, NY (United States)

    2017-01-01

    X-ray and neutron scattering techniques are capable of acquiring information about the structure and dynamics of quantum matter. However, the high-field magnet systems currently available at x-ray and neutron scattering facilities in the United States are limited to fields of 16 tesla (T) at maximum, which precludes applications that require and/or study ultra-high field states of matter. This gap in capability—and the need to address it—is a central conclusion of the 2005 National Academy of Sciences report by the Committee on Opportunities in High Magnetic Field Science. To address this gap, we propose a magnet development program that would more than double the field range accessible to scattering experiments. With the development and use of new ultra-high field–magnets, the program would bring into view new worlds of quantum matter with profound impacts on our understanding of advanced electronic materials.

  16. Study of 1 MW neutron source synchrotron dual frequency power circuit for the main ring magnets

    International Nuclear Information System (INIS)

    McGhee, D.G.

    1993-01-01

    This paper describes the proposed design of the resonant power circuits for the 1-MW neutron source synchrotron's main ring magnets. The synchrotron is to have a duty cycle of 30 Hz with a maximum upper limit of operation corresponding to 2.0 GeV and a maximum design value of 2.2 GeV. A stability of 30 ppM is the design goal for the main bending and focusing magnets (dipoles and quadruples), in order to achieve an overall stabffity of 100 ppm when random field and position errors of the magnets are included. The power circuits of this design are similar to those used in Argonne's Intense Pulsed Neutron Source (IPNS) where the energy losses during each cycle are supplied by continuous excitation from modulated multiphase DC power supplies. Since only 50% of the 30-Hz sinewave is used for acceleration, a dual-frequency resonant magnet circuit is used in this design. The 30-Hz repetition rate is maintained with a 20-Hz magnet guide field during acceleration and a 60-Hz reset field when no beam is present. This lengthens the guide-field rise time and shortens the fall time, improving the duty factor for acceleration. The maximum B dot is reduced by 33% during acceleration and hence, the maximum rf voltage/turn is reduced by 56%

  17. Neutron radiography, a powerful method to determine time-dependent moisture distributions in concrete

    International Nuclear Information System (INIS)

    Zhang Peng; Wittmann, Folker H.; Zhao Tiejun; Lehmann, Eberhard H.; Vontobel, Peter

    2011-01-01

    Highlights: ► For the first time water movement in cement-based materials could be quantified in a non-destructive way. ► neutron radiography has a sensitivity and a spatial resolution unknown so far. ► Results are essential for prediction of service life. ► Results will contribute to more durable and more ecological construction. - Abstract: Service life of reinforced concrete structures is often limited by penetration of water and compounds dissolved in water into concrete. Concrete can be damaged in this way and corrosion of steel reinforcement can be initiated. There is an urgent need to study water penetration into concrete in order to better understand deterioration mechanisms and to find appropriate ways to improve durability. Neutron radiography provides us with an advanced non-destructive technique with high spatial resolution and extraordinary sensitivity. In this contribution, neutron radiography was successfully applied to study the process of water absorption of two types of concrete with different water–cement ratios, namely 0.4 and 0.6. The influence cracks and of water repellent treatment on water absorption has been studied on mortar specimens. It is possible to visualize migration of water into concrete and other cement-based composites and to quantify the time-dependent moisture distributions as function of time with high spatial resolution by means of neutron radiography. Water penetration depth obtained from neutron radiography is in good agreement with corresponding values obtained from capillary suction tests. Surface impregnation of concrete with silane prevents capillary uptake of water. Even fine cracks are immediately filled with water as soon as the surface gets in contact. Results provide us with a solid basis for a better understanding of deteriorating processes in concrete and other cement-based materials.

  18. Albedo Neutron Dosimetry in a Deep Geological Disposal Repository for High-Level Nuclear Waste.

    Science.gov (United States)

    Pang, Bo; Becker, Frank

    2017-04-28

    Albedo neutron dosemeter is the German official personal neutron dosemeter in mixed radiation fields where neutrons contribute to personal dose. In deep geological repositories for high-level nuclear waste, where neutrons can dominate the radiation field, it is of interest to investigate the performance of albedo neutron dosemeter in such facilities. In this study, the deep geological repository is represented by a shielding cask loaded with spent nuclear fuel placed inside a rock salt emplacement drift. Due to the backscattering of neutrons in the drift, issues concerning calibration of the dosemeter arise. Field-specific calibration of the albedo neutron dosemeter was hence performed with Monte Carlo simulations. In order to assess the applicability of the albedo neutron dosemeter in a deep geological repository over a long time scale, spent nuclear fuel with different ages of 50, 100 and 500 years were investigated. It was found out, that the neutron radiation field in a deep geological repository can be assigned to the application area 'N1' of the albedo neutron dosemeter, which is typical in reactors and accelerators with heavy shielding. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  19. The neutron dose equivalent around high energy medical electron linear accelerators

    Directory of Open Access Journals (Sweden)

    Poje Marina

    2014-01-01

    Full Text Available The measurement of neutron dose equivalent was made in four dual energy linear accelerator rooms. Two of the rooms were reconstructed after decommissioning of 60Co units, so the main limitation was the space. The measurements were performed by a nuclear track etched detectors LR-115 associated with the converter (radiator that consist of 10B and with the active neutron detector Thermo BIOREM FHT 742. The detectors were set at several locations to evaluate the neutron ambient dose equivalent and/or neutron dose rate to which medical personnel could be exposed. Also, the neutron dose dependence on collimator aperture was analyzed. The obtained neutron dose rates outside the accelerator rooms were several times smaller than the neutron dose rates inside the accelerator rooms. Nevertheless, the measured neutron dose equivalent was not negligible from the aspect of the personal dosimetry with almost 2 mSv a year per person in the areas occupied by staff (conservative estimation. In rooms with 15 MV accelerators, the neutron exposure to the personnel was significantly lower than in the rooms having 18 MV accelerators installed. It was even more pronounced in the room reconstructed after the 60Co decommissioning. This study confirms that shielding from the neutron radiation should be considered when building vaults for high energy linear accelerators, especially when the space constraints exist.

  20. Powering the High-Luminosity Triplets

    Science.gov (United States)

    Ballarino, A.; Burnet, J. P.

    The powering of the magnets in the LHC High-Luminosity Triplets requires production and transfer of more than 150 kA of DC current. High precision power converters will be adopted, and novel High Temperature Superconducting (HTS) current leads and MgB2 based transfer lines will provide the electrical link between the power converters and the magnets. This chapter gives an overview of the systems conceived in the framework of the LHC High-Luminosity upgrade for feeding the superconducting magnet circuits. The focus is on requirements, challenges and novel developments.

  1. Measurement of highly enriched uranium metal buttons with the high-level neutron coincidence counter operating in the active mode

    International Nuclear Information System (INIS)

    Foley, J.E.

    1980-10-01

    The portable High-Level Neutron Coincidence Counter is used in the active mode with the addition of AmLi neutron sources to assay the 235 U content of highly enriched metal pieces or buttons. It is concluded that the portable instrument is a practical instrument for assaying uranium metal buttons with masses in the range 1.5 to 4 kg

  2. Development of High Intensity D-T fusion NEutron Generator (HINEG)

    Science.gov (United States)

    Wu, Yican; Liu, Chao; Song, Gang; Wang, Yongfeng; Li, Taosheng; Jiang, Jieqiong; Song, Yong; Ji, Xiang

    2017-09-01

    A high intensity D-T fusion neutron generator (HINEG) is keenly needed for the research and development (R&D) of nuclear technology and safety of the advanced nuclear energy system, especially for the radiation protection and shielding. The R&D of HINEG includes two phases: HINEG-I and HINEG-II. HINEG-I is designed to have both the steady beam and pulsed beam. The neutron yield of the steady beam is up to 1012 n/s. The width of pulse neutron beam is less than 1.5 ns. HINEG-I is used for the basic neutronics study, such as measurement of nuclear data, validation of neutronics methods and software, validation of radiation protection and so on. HINEG-II aims to generate a high neutron yield of 1013 n/s neutrons by adopting high speed rotating tritium target system integrated with jet/spray array enhanced cooling techniques, and can further upgrade to obtain neutron yield of 1014 1015n/s by using of accelerators-array in a later stage. HINEG-II can be used for fundamentals research of nuclear technology including mechanism of materials radiation damage and neutronics performance of components, radiation shielding as well as other nuclear technology applications.

  3. Development of High Intensity D-T fusion NEutron Generator (HINEG

    Directory of Open Access Journals (Sweden)

    Wu Yican

    2017-01-01

    Full Text Available A high intensity D-T fusion neutron generator (HINEG is keenly needed for the research and development (R&D of nuclear technology and safety of the advanced nuclear energy system, especially for the radiation protection and shielding. The R&D of HINEG includes two phases: HINEG-I and HINEG-II. HINEG-I is designed to have both the steady beam and pulsed beam. The neutron yield of the steady beam is up to 1012 n/s. The width of pulse neutron beam is less than 1.5 ns. HINEG-I is used for the basic neutronics study, such as measurement of nuclear data, validation of neutronics methods and software, validation of radiation protection and so on. HINEG-II aims to generate a high neutron yield of 1013 n/s neutrons by adopting high speed rotating tritium target system integrated with jet/spray array enhanced cooling techniques, and can further upgrade to obtain neutron yield of 1014~1015n/s by using of accelerators-array in a later stage. HINEG-II can be used for fundamentals research of nuclear technology including mechanism of materials radiation damage and neutronics performance of components, radiation shielding as well as other nuclear technology applications.

  4. High current and high power superconducting rectifiers

    International Nuclear Information System (INIS)

    Kate, H.H.J. ten; Bunk, P.B.; Klundert, L.J.M. van de; Britton, R.B.

    1981-01-01

    Results on three experimental superconducting rectifiers are reported. Two of them are 1 kA low frequency flux pumps, one thermally and magnetically switched. The third is a low-current high-frequency magnetically switched rectifier which can use the mains directly. (author)

  5. Experimental astrophysics with high power lasers and Z pinches

    Energy Technology Data Exchange (ETDEWEB)

    Remington, B A; Drake, R P; Ryutov, D D

    2004-12-10

    With the advent of high energy density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, mm-scale quantities of matter can be placed in extreme states of density, temperature, and/or velocity. This has enabled the emergence of a new class of experimental science, HED laboratory astrophysics, wherein the properties of matter and the processes that occur under extreme astrophysical conditions can be examined in the laboratory. Areas particularly suitable to this class of experimental astrophysics include the study of opacities relevant to stellar interiors; equations of state relevant to planetary interiors; strong shock driven nonlinear hydrodynamics and radiative dynamics, relevant to supernova explosions and subsequent evolution; protostellar jets and high Mach-number flows; radiatively driven molecular clouds and nonlinear photoevaporation front dynamics; and photoionized plasmas relevant to accretion disks around compact objects, such as black holes and neutron stars.

  6. Measuring delayed part of the current of a self powered neutron detector and comparison with calculations

    International Nuclear Information System (INIS)

    Kophazi, J.; Czifrus, Sz.; Feher, S.; Por, G.

    2001-01-01

    The paper describes the measurement of the delayed signal of a Rh emitter Self Powered Neutron Detector (SPND) separately from other signal components originating from (n-gamma-e), (background gamma-e) and other effects. In order to separate the delayed signal, the detector was removed from the reactor core and placed to an adequately distant location during the measurement, where the radiation from the core was negligible. The experiment was carried out on the 100kW light water tank-type reactor of Technical University of Budapest and the results of the measurement were compared with the results of Monte Carlo calculations.(author)

  7. In-reactor testing of self-powered neutron detectors and miniature fission chambers

    International Nuclear Information System (INIS)

    Duchene, J.; LeMeur, R.; Verdant, R.

    1975-01-01

    The CEA has tested a variety of ''slow'' self-powered neutron detectors with rhodium, silver and vanadium emitters. Currently there are 120 vanadium detectors in the EL4 heavy water reactor. In addition, ''fast'' detectors with cobalt emitters have been tested at Saclay and 50 of these are in reactor. Other studies are concerned with 6 mm diameter miniature fission chambers. Two fast response chambers with argon-nitrogen filling gas became slow during irradiation, but operated to 600 deg C. An argon filled chamber of 4.7 mm diameter, for traversing in core system in pressurized water reactor, has shown satisfactory test results. (author)

  8. High power ultrashort pulse lasers

    International Nuclear Information System (INIS)

    Perry, M.D.

    1994-01-01

    Small scale terawatt and soon even petawatt (1000 terawatt) class laser systems are made possible by application of the chirped-pulse amplification technique to solid-state lasers combined with the availability of broad bandwidth materials. These lasers make possible a new class of high gradient accelerators based on the large electric fields associated with intense laser-plasma interactions or from the intense laser field directly. Here, we concentrate on the laser technology to produce these intense pulses. Application of the smallest of these systems to the production of high brightness electron sources is also introduced

  9. Evolution of Very High Frequency Power Supplies

    DEFF Research Database (Denmark)

    Knott, Arnold; Andersen, Toke Meyer; Kamby, Peter

    2013-01-01

    The ongoing demand for smaller and lighter power supplies is driving the motivation to increase the switching frequencies of power converters. Drastic increases however come along with new challenges, namely the increase of switching losses in all components. The application of power circuits used...... in radio frequency transmission equipment helps to overcome those. However those circuits were not designed to meet the same requirements as power converters. This paper summarizes the contributions in recent years in application of very high frequency (VHF) technologies in power electronics, shows results...... of the recent advances and describes the remaining challenges. The presented results include a self-oscillating gate-drive, air core inductor optimizations, an offline LED driver with a power density of 8.9 W/cm3 and a 120 MHz, 9 W DC powered LED driver with 89 % efficiency as well as a bidirectional VHF...

  10. The NASA CSTI High Capacity Power Project

    International Nuclear Information System (INIS)

    Winter, J.; Dudenhoefer, J.; Juhasz, A.; Schwarze, G.; Patterson, R.; Ferguson, D.; Schmitz, P.; Vandersande, J.

    1992-01-01

    This paper describes the elements of NASA's CSTI High Capacity Power Project which include Systems Analysis, Stirling Power Conversion, Thermoelectric Power Conversion, Thermal Management, Power Management, Systems Diagnostics, Environmental Interactions, and Material/Structural Development. Technology advancement in all elements is required to provide the growth capability, high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall project will develop and demonstrate the technology base required to provide a wide range of modular power systems compatible with the SP-100 reactor which facilitates operation during lunar and planetary day/night cycles as well as allowing spacecraft operation at any attitude or distance from the sun. Significant accomplishments in all of the project elements will be presented, along with revised goals and project timeliness recently developed

  11. Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

    Energy Technology Data Exchange (ETDEWEB)

    Williams, R.E.

    1981-10-12

    The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed.

  12. Gamma-ray-spectroscopy following high-flux 14-MeV neutron activation

    International Nuclear Information System (INIS)

    Williams, R.E.

    1981-01-01

    The Rotating Target Neutron Source (RTNS-I), a high-intensity source of 14-MeV neutrons at the Lawrence Livermore National Laboratory (LLNL), has been used for applications in activation analysis, inertial-confinement-fusion diagnostic development, and fission decay-heat studies. The fast-neutron flux from the RTNS-I is at least 50 times the maximum fluxes available from typical neutron generators, making these applications possible. Facilities and procedures necessary for gamma-ray spectroscopy of samples irradiated at the RTNS-I were developed

  13. Single event upset and charge collection measurements using high energy protons and neutrons

    International Nuclear Information System (INIS)

    Normand, E.; Oberg, D.L.; Wert, J.L.; Ness, J.D.; Majewski, P.P.; Wender, S.; Gavron, A.

    1994-01-01

    RAMs, microcontrollers and surface barrier detectors were exposed to beams of high energy protons and neutrons to measure the induced number of upsets as well as energy deposition. The WNR facility at Los Alamos provided a neutron spectrum similar to that of the atmospheric neutrons. Its effect on devices was compared to that of protons with energies of 200, 400, 500, and 800 MeV. Measurements indicate that SEU cross sections for 400 MeV protons are similar to those induced by the atmospheric neutron spectrum

  14. HIGH AVERAGE POWER OPTICAL FEL AMPLIFIERS

    International Nuclear Information System (INIS)

    2005-01-01

    Historically, the first demonstration of the optical FEL was in an amplifier configuration at Stanford University [l]. There were other notable instances of amplifying a seed laser, such as the LLNL PALADIN amplifier [2] and the BNL ATF High-Gain Harmonic Generation FEL [3]. However, for the most part FELs are operated as oscillators or self amplified spontaneous emission devices. Yet, in wavelength regimes where a conventional laser seed can be used, the FEL can be used as an amplifier. One promising application is for very high average power generation, for instance FEL's with average power of 100 kW or more. The high electron beam power, high brightness and high efficiency that can be achieved with photoinjectors and superconducting Energy Recovery Linacs (ERL) combine well with the high-gain FEL amplifier to produce unprecedented average power FELs. This combination has a number of advantages. In particular, we show that for a given FEL power, an FEL amplifier can introduce lower energy spread in the beam as compared to a traditional oscillator. This properly gives the ERL based FEL amplifier a great wall-plug to optical power efficiency advantage. The optics for an amplifier is simple and compact. In addition to the general features of the high average power FEL amplifier, we will look at a 100 kW class FEL amplifier is being designed to operate on the 0.5 ampere Energy Recovery Linac which is under construction at Brookhaven National Laboratory's Collider-Accelerator Department

  15. Probe high-Tc Superconductors by neutron scattering

    International Nuclear Information System (INIS)

    Fauque, B.

    2007-10-01

    This research thesis explores two aspects of the phase diagram of high critical temperature superconductors: the evolution of AF correlations and the nature of the pseudo-gap phase. The author presents the problematic associated with these particular semiconductors, describes the neutron diffusion probe used in this study, and presents the three families of semiconductors investigated during this research: Bi 2 Sr 2 CaCu 2 O 8+x , YBa 2 Cu 3 O 6+x and La 2-x Sr x CuO 4 . He reports the results of the investigation of the spin dynamics in the Bi 2 Sr 2 CaCu 2 O 8+x . He reports a detailed investigation of the magnetic cross section associated with different types of non conventional magnetic orders proposed as candidates for the pseudo-gap phase. He reports and comments the results obtained for the pseudo-gap phase for the YBa 2 Cu 3 O 6+x and La 2-x Sr x CuO 4 families. Finally, the author discusses the consequences of the obtained results for the description of the diagram phase of high critical temperature semiconductors

  16. Inelastic neutron scattering from high-density fcc 4He

    International Nuclear Information System (INIS)

    Thomlinson, W.; Eckert, J.; Shirane, G.

    1978-01-01

    The phonon dispersion relations in high-density crystals of fcc 4 He have been measured along high-symmetry directions by the neutron-inelastic-scattering technique. A recent study of the lattice dynamics of fcc 4 He by Eckert et al. has been extended to cover the fcc phase diagram at pressures below 5 kbar. Molar volumes of 9.03, 9.43, and 9.97 cm 3 /mole have been studied in the temperature range from near the melting curve to near the fcc-hcp transition line. The phonon dispersion relations are in good agreement with a first-order self-consistent phonon theory calculation by Goldman. The observed phonon-group line shapes at large energy and momentum transfers show evidence for multiphonon scattering in agreement with calculations by Glyde. Eckert et al. reported extremely large anharmonic isochoric temperature shifts of the phonon energies. The present work studied the shifts as a function of molar volume and temperature. Mode-Grueneisen-parameter dispersion curves have been measured using the present data and earlier measurements at lower density in the fcc phase by Traylor et al. Macroscopic Grueneisen parameters have been calculated from the phonon density of states obtained from the data

  17. ACIGA's high optical power test facility

    International Nuclear Information System (INIS)

    Ju, L; Aoun, M; Barriga, P

    2004-01-01

    Advanced laser interferometer detectors utilizing more than 100 W of laser power and with ∼10 6 W circulating laser power present many technological problems. The Australian Consortium for Interferometric Gravitational Astronomy (ACIGA) is developing a high power research facility in Gingin, north of Perth, Western Australia, which will test techniques for the next generation interferometers. In particular it will test thermal lensing compensation and control strategies for optical cavities in which optical spring effects and parametric instabilities may present major difficulties

  18. Active neutron and gamma-ray imaging of highly enriched uranium for treaty verification.

    Science.gov (United States)

    Hamel, Michael C; Polack, J Kyle; Ruch, Marc L; Marcath, Matthew J; Clarke, Shaun D; Pozzi, Sara A

    2017-08-11

    The detection and characterization of highly enriched uranium (HEU) presents a large challenge in the non-proliferation field. HEU has a low neutron emission rate and most gamma rays are low energy and easily shielded. To address this challenge, an instrument known as the dual-particle imager (DPI) was used with a portable deuterium-tritium (DT) neutron generator to detect neutrons and gamma rays from induced fission in HEU. We evaluated system response using a 13.7-kg HEU sphere in several configurations with no moderation, high-density polyethylene (HDPE) moderation, and tungsten moderation. A hollow tungsten sphere was interrogated to evaluate the response to a possible hoax item. First, localization capabilities were demonstrated by reconstructing neutron and gamma-ray images. Once localized, additional properties such as fast neutron energy spectra and time-dependent neutron count rates were attributed to the items. For the interrogated configurations containing HEU, the reconstructed neutron spectra resembled Watt spectra, which gave confidence that the interrogated items were undergoing induced fission. The time-dependent neutron count rate was also compared for each configuration and shown to be dependent on the neutron multiplication of the item. This result showed that the DPI is a viable tool for localizing and confirming fissile mass and multiplication.

  19. High Hydrogen Content Graphene Hydride Compounds & High Cross-Section Cladding Coatings for Fast Neutron Detection

    International Nuclear Information System (INIS)

    Chandrashekhar, MVS

    2017-01-01

    The objective is to develop and implement a superior low-cost, large area (potentially >32in), easily deployable, close proximity, harsh environment innovative neutron sensor needed for next generation fuel cycle monitoring. We will exploit recent breakthroughs at the PI's lab on the electrochemistry of epitaxial graphene (EG) formed on commercial SiC wafers, a transformative nanomaterial system with superior radiation detection and durability properties to develop a new paradigm in detection for fast neutrons, a by-product of fission reactors. There are currently few effective detection/monitoring schemes, especially solid-state ones at present. This is essential for monitoring and control of future fuel cycles to make them more efficient and reliable. By exploiting these novel materials, as well as innovative hybrid SiC/EG/Cladding device architectures conceived by the team, will develop low-cost, high performance solutions to fast-neutron detection. Finally, we will also explore 3-terminal device implementations for neutron detectors with built-in electronic gain to further shrink these devices and improve their sensitivity.

  20. Neutron radiography with the cyclotron

    International Nuclear Information System (INIS)

    Tazawa, Shuichi; Asada, Yorihisa; Yano, Munehiko; Nakanii, Takehiko.

    1985-01-01

    Neutron radiography is well recognized as a powerful tool in nondestructive testing, but not widely used yet owing to lack of high intense thermal neutron source convenient for practical use. This article presents a new neutron radiograph facility, utilizing a sub-compact cyclotron as neutron source and is equipped with vertical and horizontal irradiation ports. The article describes a series of experiments, we conducted using beams of a variable energy cyclotron at Tohoku University to investigate the characteristics of thermal neutron obtained from 9 Be(p, n) reaction and thermalized by elastic scattering process. The article also describes a computer simulation of neutron moderator to analyze conditions getting maximal thermal neutron flux. Further, some of practical neutron radiograph examinations of aero-space components and museum art objects of classic bronze mirror and an attempt realizing real time imaging technique, are introduced in the article. (author)