Design, Construction and Characterization of an External Neutron Beam Facility at The Ohio State University Nuclear Reactor Laboratory PDF Download

Author: Danyal J. Turkoglu
Publisher:
ISBN:
Category :
Languages : en
Pages : 93

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Book Description
Abstract: The objective of this research was to bring a thermal neutron beam facility to the Ohio State University Nuclear Reactor Laboratory for the purposes of neutron-based research. The neutron beam is extracted from the reactor core through a neutron collimator emplaced in Beam Port #2, the radial beam port facing the core at a 30° angle. The collimator is an aluminum tube containing components designed to filter and shape the neutron beam. The filters are poly-crystalline bismuth (10.16 cm thickness, 12.7 cm diameter) for significantly reducing gamma ray content and single-crystal sapphire (12.7 cm thickness, 10.16 cm diameter) for preferentially passing thermal neutrons while scattering more energetic neutrons out of the beam. The thermal neutron beam is defined by multiple 3.0 cm diameter apertures in borated aluminum. Apertures in polyethylene-based disks and in Pb disks provide shielding for fast neutrons and gamma rays, respectively, in the neutron collimator. Characterization of the beam was performed using foil activation analysis to find the neutron flux and a low-cost digital neutron imaging apparatus to "see" the beam profile. The neutron collimator delivers the filtered thermal neutron beam with a 3.5 cm diameter umbra and a thermal neutron equivalent flux of (8.55 +̲ 0.19) x 106 cm−2s−1 at 450 kW reactor power (90% of rated limit) to the sample location. The beam is highly thermalized with a cadmium ratio of 266 +̲ 13. The facility was designed for neutron depth profiling, a nondestructive analytical technique for finding the concentration versus depth in the near surface (tens of microns) for isotopes that undergo charged particle emitting reactions, such as 10B(n, 4He)7Li, 6Li (n, 3H)4He, and 3He (n, 1H)3H, to name a few.

Author: Andrew M. Zapp
Publisher:
ISBN:
Category : Fast neutrons
Languages : en
Pages : 112

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Book Description
The ability of the Ohio State University Research Reactor, OSURR, to conduct experiments from the generation of the neutron flux is important in conducting research by the University and external entities that require a flux of this magnitude. In particular, research involving a fast neutron flux is of interest due to the different interactions fast neutrons have as opposed to thermal neutrons. The OSURR is able to operate up to 500 kW, which creates a neutron flux in the order of 1013 n/cm2-s. Currently, Beam Port 2 provides a thermal neutron beam profile of 30 mm in diameter for experimentation such as neutron depth profiling, activation analysis, and evaluation of radiation damage to electronics. Beam Port 1 uses a sample area located adjacent and perpendicular to the fuel plates of the reactor for in-core irradiation. During experimentation, the remainder of Beam Port 1 must be plugged with removable concrete shielding to prevent radiation exposure that can be upwards of 1x104 rem/hr. The upgrade to Beam Port 1 consists of a collimator to shape the neutron flux from the reactor into a beam of fast neutrons, similar in diameter to Beam Port 2, in order to irradiate samples external to the reactor. In addition, mobile external shielding is designed to prevent exceeding the exposure limits of 5 rem/yr when the facility is in use. With this upgrade the research reactor has the ability to conduct simultaneous experiments with a fast and thermal neutron beam, external to the biological shielding, without releasing any harmful exposure.

Author: Daniel Caldwell Barron
Publisher:
ISBN:
Category :
Languages : en
Pages : 518

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A fast neutron irradiation facility has been designed, modeled, and constructed in the beam port 4 facility at The University of Texas at Austin’s TRIGA Mark-II Reactor. This facility targets the Watt-fission neutron spectrum in a controlled environment by reducing the present thermal and epithermal flux while preserving the fast neutron flux. The present facility will open new avenues in nuclear non-proliferation for fast-fission yields in addition to measuring radionuclide migration. The filter system was designed using MCNP and Solidworks and consists of a lead plug to stop gamma-rays, filter elements of natural boron and 96% enriched B10, collimation elements of borated polyethylene and natural boron, and an exit filter of boron nitride. A beam stop was constructed to reduce the ambient dose rate using borated paraffin wax, polyethylene, cadmium, and lead. Sensitivity studies were performed to configure an economic facility by optimizing the amounts and configurations of materials used in the filter. The filter is modular to allow for rearrangement of elements and the ability to change the materials used as needed should higher efficiencies be desired or a higher total flux. Initial results indicate the facility produces a 10 cm diameter beam with an integrated flux of 6.63x105 n/cm2/s at a reactor power of 950 kW and resembles the Watt-fission spectrum well with a slightly elevated epithermal neutron flux. The fast neutron flux above 0.1 MeV constitutes 98.77% of the total flux and the thermal neutron flux only 0.0014% of the total flux. STAYSL PNNL was used to unfold the neutron spectrum from 9 measurable reactions in 5 flux foils. Results suggest that the fast neutron flux is higher than anticipated in all STAYSL runs although the total flux is lower than anticipated.

Author:
Publisher:
ISBN:
Category : Nuclear energy
Languages : en
Pages : 1550

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Author: Alibek Kenges
Publisher:
ISBN:
Category : Imaging systems
Languages : en
Pages : 0

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Book Description
Neutron imaging is a powerful tool in the field of non-destructive testing that utilizes unique attenuation properties of neutrons allowing through-images of some high-density objects. The Radiation Science and Engineering Center (RSEC) has had a neutron imaging facility for the last several decades. With the installation of a new core moderator assembly and new beam ports at the RSEC -- the Penn State Breazeale Reactor (PSBR) in 2018, a dedicated neutron beam port became available for a new neutron imaging facility at RSEC (RSEC -- NIF). The initial design of the beam port designated for the RSEC -- NIF was of divergent type that needed to be upgraded by means of collimator components and filters. After a thorough investigation of existing neutron imaging facilities around the world, it has been decided to collimate the beam port with convergent and divergent collimators and to filter the gamma and neutron content with the single crystal bismuth and sapphire filters. A set of system characterization experiments were conducted at the RSEC -- NIF that confirmed the system's correspondence to a Category I facility by ASTM standards. In addition to that, the collimation ratio of the new system was measured following the procedures given in the ASTM protocols and resulted in the effective L/D ratio value between 107 and 115. The thermal flux across the exit surface from the beam port at the biological shield was measured to be equal to 5.4E+06 n/cm^2-s at 1MWth reactor power. The application of the RSEC -- NIF's capabilities in neutron radiography (NR) and tomography (NT) techniques were demonstrated imaging different types of environmental samples for the presence and visualization of microplastic particles. Preliminary results of NT experiments conducted at the RSEC -- NIF have shown that this technique can be used as an intermediary step to visualize the content and spatial distribution of microplastics in the sand columns. Additionally, the NR capabilities of the RSEC -- NIF were utilized to visualize the microplastic particles in the sediment samples and used water filters. All obtained results and the continuation of research in this direction can potentially shed some light in the general research of microplastic transport mechanisms in different terrestrial and aquatic ecosystems.

Author: Otto K. Harling
Publisher: Springer Science & Business Media
ISBN: 1468458027
Category : Medical
Languages : en
Pages : 340

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Book Description
For this Workshop, the organizers have attempted to invite experts from all known centers which are engaged in neutron beam development for neutron capture therapy. The Workshop was designed around a series of nineteen invited papers which dealt with neutron source design and development and beam characterization and performance. Emphasis was placed on epithermal beams because they offer clinical advantages and are more challenging to implement than thermal beams. Fission reactor sources were the basis for the majority of the papers; however three papers dealt with accelerator neutron sources. An additional three invited papers provided a summary of clinical results of Ncr therapy in Japan between 1968 and 1989 and overviews of clinical considerations for neutron capture therapy and of the status of tumor targeting chemical agents for Ncr. Five contributed poster papers dealing with NCT beam design and performance were also presented. A rapporteurs' paper was prepared after the Workshop to attempt to summarize the major aspects, issues, and conclusions which resulted from this Workshop. Many people contributed to both the smooth functioning of the Workshop and to the preparation of these proceedings. Special thanks are reserved for Ms. Dorothy K.

Author: Takashi Emoto
Publisher:
ISBN:
Category :
Languages : en
Pages : 196

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Author: Joshua A. Robinson
Publisher:
ISBN:
Category : Nuclear activation analysis
Languages : en
Pages : 144

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Book Description
In this work, Neutron Depth Profiling (NDP) analysis capability has been added to the Oregon State University TRIGA® Reactor Prompt Gamma Neutron Activation Analysis Facility (PGNAA). This system has been implemented with an advanced digital spectroscopy system and is capable of rise time pulse shape analysis as well as coincidence measurements from multiple detectors. The digital spectroscopy system utilizes a high-speed multichannel digitizer with speeds up to 200 Megasamples/second (MS/s) with advanced hardware trigger and time stamping capabilities. These additions allow the facility to conduct simultaneous NDP and PGNAA combined measurements, which also enables cross calibration. The digital pulse processing is implemented with software programmed rise time pulse shape analysis capabilities for the analysis of the detector responses on a pulse-by-pulse basis to distinguish between different interactions in the detector. The advanced trigger capabilities of the digitizer were configured to accurately measure and correct for dead time effects from pulse pile up and preamplifier decay time.

Author: International Atomic Energy Agency
Publisher:
ISBN:
Category : Materials
Languages : en
Pages : 82

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"This publication is a compilation of the main results and findings of an IAEA coordinated research project (CRP) on development, characterization and testing of materials of relevance to nuclear energy sector using neutron beams. The document contains joint research results from nineteen institutions, which can be grouped into the main six technical areas: investigation of oxide dispersion-strengthened steels, research on zirconium based materials (including hydrogen uptake), investigations of welded structures and objects, results with irradiated materials, optimization of instruments for residual strain/stress measurements, and efforts towards standardization of neutron imaging. Particular emphasis was placed on variable environments during material characterization and testing as required by some applications such as intensive irradiation load, high temperature and high pressure conditions, and the presence of strong magnetic fields. The publication also includes some additional materials supplied by the international experts along with nineteen individual contributions describing the current status of use of diverse neutron beam techniques for materials research targeting the nuclear energy sector. These nineteen individual reports are available on CD-ROM attached to this publication. The publication will be of interest to physicists and engineers in the area of materials research, neutron beam scientists and personnel responsible for instruments, managers of neutron beam facilities, nuclear reactor designers and nuclear industry representatives."--Publisher's description.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The quality of a neutron imaging beam directly impacts the quality of radiographic images produced using that beam. Fully characterizing a neutron beam, including determination of the beam's effective length-to-diameter ratio, neutron flux profile, energy spectrum, image quality, and beam divergence, is vital for producing quality radiographic images. This project characterized the east neutron imaging beamline at the Idaho National Laboratory Neutron Radiography Reactor (NRAD). The experiments which measured the beam's effective length-to-diameter ratio and image quality are based on American Society for Testing and Materials (ASTM) standards. An analysis of the image produced by a calibrated phantom measured the beam divergence. The energy spectrum measurements consist of a series of foil irradiations using a selection of activation foils, compared to the results produced by a Monte Carlo n-Particle (MCNP) model of the beamline. Improvement of the existing NRAD MCNP beamline model includes validation of the model's energy spectrum and the development of enhanced image simulation methods. The image simulation methods predict the radiographic image of an object based on the foil reaction rate data obtained by placing a model of the object in front of the image plane in an MCNP beamline model.