ORR reactor

8/11/2019 ORR reactor

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HFIR In the Oak Ridge Countryside

High Flux Isotope ReactorFrom Wikipedia, the free encyclopedia

The High Flux Isot ope Reac tor (or HFIR ) is a nuclear research reactor located at Oak Ridge NationalLaboratory (ORNL) in Oak Ridge, Tennessee, United States. Operating at 85 MW, HFIR is one of thehighest flux reactor-based sources of neutrons for condensed matter research in the United States, and itprovides one of the highest steady-state neutron fluxes of any research reactor in the world. The thermal cold neutrons produced by HFIR are used to study physics, chemistry, materials science, engineering, andbiology. The intense neutron flux, constant power density, and constant-length fuel cycles are used by mthan 500 researchers each year for neutron scattering research into the fundamental properties of condenmatter. HFIR has approximately 600 users each year for both scattering and in-core research.

The neutron scattering research facilities at HFIR contain a world-class collection of instruments used for fundamental and appliedresearch on the structure and dynamics of matter. The reactor is alsoused for medical, industrial, and research isotope production; researchon severe neutron damage to materials; and neutron activation to

examine trace elements in the environment. Additionally, the buildinghouses a gamma irradiation facility that uses spent fuel assemblies andis capable of accommodating high gamma dose experiments.

With projected regular operations, the next major shutdown for aberyllium reflector replacement will not be necessary untilapproximately 2023. This outage provides an opportunity to install acold source in radial beam tube HB-2, which would provide anunparalleled flux of cold neutrons feedinginstruments in a new guide hall. With or without this additionalcapability, HFIR is projected to continueoperating through 2040 and beyond.

In November 2007 ORNL officials announced that time-of-flight tests on a newly installed cold source(which uses liquid helium and hydrogen to slow the movement of neutrons) showed better performancedesign predictions, equaling or surpassing the previous world record set by the research reactor at the InLaue-Langevin in Grenoble, France.[1]

Contents

1 History2 Technical Description of HFIR[2]

2.1 Reactor Core Assembly2.2 Horizontal Beam Tubes

2.2.1 HB-1 and HB-32.2.2 HB-22.2.3 HB-4

Coordinates: 35.9181N 84.3040
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High Flux Isotope Reactor Timeline

3 In-Core Experiment Facilities3.1 Flux Trap Positions

3.1.1 Target Positions3.1.2 Peripheral Target Positions3.1.3 Hydraulic Tube Facility

3.2 Large Removable Beryllium Reflector Facilities

3.3 Small Removable Beryllium Facilities3.4 Control-Rod Access Plug Facilities3.5 Small Vertical Experiment Facilities3.6 Large Vertical Experiment Facilities3.7 Slant Engineering Facilities

4 Gamma Irradiation Facility4.1 Overview4.2 Radiation Dose Rates and Accumulated Doses4.3 Temperatures

5 Neutron Activation Analysis5.1 Program Highlights

5.1.1 Nuclear Nonproliferation5.2 Environmental5.3 Forensics5.4 Isotope Production

5.5 Ultra-Trace Metrology5.6 Materials Irradiation

6 References7 External links

History

In January 1958, the U.S. Atomic Energy Commission (AEC)reviewed the status of transuranium isotope production in the UnitedStates. By November of the same year, the commission decided tobuild the High Flux Isotope Reactor (HFIR) at Oak Ridge NationalLaboratory, with a fundamental focus on isotope research andproduction. Since it first went critical in 1965, the in-core uses forHFIR have broadened to include materials research, fuels research,and fusion energy research, in addition to isotope production andresearch for medical, nuclear, detector and security purposes.
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A low-power testing program was completed in January 1966, and operation cycles at 20, 50, 75, 90, aMW began. From the time it attained its design power of 100 MW in September 1966, a little over fivefrom the beginning of its construction, until it was temporarily shut down in late 1986, HFIR achieved record of operation time unsurpassed by any other reactor in the United States. By December 1973, it hcompleted its 100th fuel cycle, each lasting approximately 23 days.

In November 1986, tests on irradiation surveillance specimens indicated that the reactor vessel was beinembrittled by neutron irradiation at a rate faster than predicted. HFIR was shut down to allow for extenreviews and evaluation of the facility. Two years and five months later, after thorough reevaluation,modifications to extend the life of the plant while protecting the integrity of the pressure vessel, and upto management practices, the reactor was restarted at 85 MW. Coincident with physical and proceduralimprovements were renewed training, safety analysis, and quality assurance activities. Documents wereupdated, and new ones were generated where necessary. Technical specifications were amended andreformatted to keep abreast of the design changes as they were accepted by the U.S. Department of En(DOE), formerly the AEC. Not only were the primary coolant pressure and core power reduced to prevessel integrity while maintaining thermal margins, but long-term commitments were made for technoloand procedural upgrades.

After a thorough review of many aspects of HFIR operation, the reactor was restarted for fuel cycle 28April 18, 1989, to operate initially at very low power levels (8.5 MW) until all operating crews were futrained and it was possible to operate continuously at higher power. Following the April 1989 restart, ashutdown of nine months occurred as a consequence of a question as to procedural adequacy. During thperiod, oversight of HFIR was transferred to the DOE Office of Nuclear Energy (NE); previously, overwas through the Office of Energy Research (ER). Following permission by Secretary of Energy JamesWatkins to resume startup operation in January 1990, full power was reached on May 18, 1990. Ongoiprograms have been established for procedural and technological upgrade of the HFIR during its operalife.

In 2007, HFIR completed the most dramatic transformation in its 40-year history. During a shutdown othan a year, the facility was refurbished and a number of new instruments were installed, as well as a cneutron source. The reactor was restarted in mid-May; it attained its full power of 85 MW within a coudays, and experiments resumed within a week. Improvements and upgrades include an overhaul of the structure for reliable, sustained operation; significant upgrading of the eight thermal-neutron spectrometthe beam room; new computer system controls; installation of the liquid hydrogen cold source; and a nneutron guide hall. The upgraded HFIR will eventually house 15 instruments, including 7 for research cold neutrons.

Although HFIR's main mission is now neutron scattering research, one of its original primary purposes

the production of californium-252 and other transuranium isotopes for research, industrial, and medicalapplications. HFIR is the western world's sole supplier of californium-252, an isotope with uses such acancer therapy and the detection of pollutants in the environment and explosives in luggage. Beyond itcontributions to isotope production and neutron scattering, HFIR also provides for a variety of irradiatioand experiments that benefit from the facility's exceptionally high neutron flux.

Technical Description of HFIR [2]
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High Flux Isotope Reactor SimplifiCore

85 MW neutron flux graph for the

High Flux Isotope Reactor

HFIR is a beryllium-reflected, light-water-cooled and -moderated,flux-trap type reactor that uses highly enriched uranium-235 as thefuel. The preliminary conceptual design of the reactor was based onthe "flux trap" principle, in which the reactor core consists of anannular region of fuel surrounding an unfueled moderating region or"island." Such a configuration permits fast neutrons leaking from thefuel to be moderated in the island and thus produces a region of veryhigh thermal-neutron flux at the center of the island. This reservoir ofthermalized neutrons is "trapped" within the reactor, making itavailable for isotope production. The large flux of neutrons in thereflector outside the fuel of such a reactor may be tapped byextending empty "beam" tubes into the reflector, thus allowingneutrons to be beamed into experiments outside the reactor shielding.Finally, a variety of holes in the reflector may be provided in which toirradiate materials for experiments or isotope production.

The original mission of HFIR was the production of transplutoniumisotopes. However, the original designers included many otherexperiment facilities, and several others have been added since then.Experiment facilities available include (1) four horizontal beam tubes,which originate in the beryllium reflector; (2) the hydraulic tubeirradiation facility, located in the very high flux region of the fluxtrap, which allows for insertion and removal of samples while thereactor is operating; (3) thirty target positions in the flux trap, whichnormally contain transplutonium production rods but which can beused for the irradiation of other experiments (two of these positionscan accommodate instrumented targets); (4) six peripheral targetpositions located at the outer edge of the flux trap; (5) numerousvertical irradiation facilities of various sizes located throughout theberyllium reflector; (6) two pneumatic tube facilities in the berylliumreflector, which allow for insertion and removal of samples while thereactor is operating for neutron activation analysis; and (7) two slant access facilities, called "engineerinfacilities," located on the outer edge of the beryllium reflector. In addition, spent fuel assemblies are useprovide a gamma irradiation facility in the reactor pool.

Reactor Core Assembly

The reactor core assembly is contained in an 8-ft (2.44-m)-diameter pressure vessel located in a pool ofThe top of the pressure vessel is 17 ft (5.18 m) below the pool surface. The control plate drive mechanare located in a sub-pile room beneath the pressure vessel. These features provide the necessary shieldinworking above the reactor core and greatly facilitate access to the pressure vessel, core, and reflector re

The reactor core is cylindrical, approximately 2 ft (0.61 m) high and 15 inches (380 mm) in diameter. A(12.70-cm)-diameter hole, referred to as the "flux trap," forms the center of the core. The target is typicloaded with curium-244 and other transplutonium isotopes and is positioned on the reactor vertical axisthe flux trap. The fuel region is composed of two concentric fuel elements. The inner element contains
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High Flux Isotope Reactor FuelAssembly Photo

High Flux Isotope Reactor VerticalCross Section

fuel plates, and the outer element contains 369 fuel plates. The fuelplates are curved in the shape of an involute, thus providing aconstant coolant channel width. The fuel (93% U235 enriched U3O8-

Al cermet[3] pg.22) is non-uniformly distributed along the arc of theinvolute to minimize the radial peak-to-average power density ratio.A burnable poison (boron-10) is included in the inner fuel elementprimarily to flatten the radial flux peak providing a longer cycle foreach fuel element. The average core lifetime with typical experimentloading is approximately 23 days at 85 MW.

The fuel region is surrounded by a concentric ring of berylliumreflector approximately 1 ft (0.30 m) thick. This in turn is subdividedinto three regions: the removable reflector, the semi permanentreflector, and the permanent reflector. The beryllium is surrounded bya water reflector of effectively infinite thickness. In the axial direction,the reactor is reflected by water. The control plates, in the form of two

thin, nuclear poison-bearing concentric cylinders, are located in anannular region between the outer fuel element and the berylliumreflector. These plates are driven in opposite directions to open andclose a window at the core mid-plane. Reactivity is increased bydownward motion of the inner cylinder and the upward motion of thefour outer quadrant plates. The inner cylinder is used for shimmingand power regulation and has no fast safety function. The outercontrol cylinder consists of four separate quadrant plates, each havingan independent drive and safety release mechanism. All control plateshave three axial regions of different neutron poison content designed

to minimize the axial peak-to-average power-density ratio throughoutthe core lifetime. Any single quadrant plate or cylinder is capable ofshutting the reactor down.

The reactor instrumentation and control system design reflects theemphasis placed on continuity of and safety of operations. Threeindependent safety channels are arranged in a coincidence system thatrequires agreement of two of the three for safety shutdowns. This feature is complemented by an extens"on-line" testing system that permits the safety function of any one channel to be tested at any time durioperation. Additionally, three independent automatic control channels are arrayed so that failure of a sin

channel will not significantly disturb operation. All of these factors contribute to the continuity of operathe HFIR.

The primary coolant enters the pressure vessel through two 16-in. (40.64-cm)-diameter pipes above thepasses through the core, and exits through an 18-in. (45.72-cm)-diameter pipe beneath the core. The flois approximately 16,000 gpm (1.01 m/s), of which approximately 13,000 gpm (0.82 m/s) flows througfuel region. The remainder flows through the target, reflector, and control regions. The system is design
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High Flux Isotope Reactor Core CrSection

A rotary shutter is located outboard of the outer collimator assembly. The shutter is fabricated using carsteel and high-density concrete. High-density concrete blocks are placed around the shutter to preventstreaming. The purpose of the shutter is to provide shielding when the neutron beam is not required.

HB-4

The HB-4 cold neutron source beam tube is situated tangential to the reactor core so that the tube point

reflector material and does not point directly at the fuel.A vacuum tube fits closely inside in-vessel section of the HB-4 beam tube all the way to the spherical eThe vacuum tube contains and insulates a hydrogen moderator vessel and its associated tubing. Themoderator vessel contains supercritical hydrogen at 17K (nominal). Thermal neutrons scattered into themoderator vessel from the reflector are scattered and cooled by the hydrogen so that the 4-12 neutronscattered down the tube are maximized.

An internal collimator is installed in the outboard end of the HB-4 tube. This collimator is fabricated oucarbon steel and is plated with nickel. The collimator provides three rectangular apertures. The outboarddimensions of the apertures are 1.61 in by 4.33 in; 2.17 in by 3.65 in; and 1.78 in by 4.33 in.

A rotary shutter is located outboard of the outer collimator assembly. The shutter is fabricated using carsteel and high-density concrete. The purpose of the shutter is to provide shielding when the neutron beanot required. The shutter has provisions for routing the cryogenic hydrogen transfer line, gaseous heliuvacuum piping necessary to support the Cold Source.

In-Core Experiment Facilities

Flux Trap Positions

Target Positions

Thirty-one target positions are provided in the flux trap. Thesepositions were originally designed to be occupied by target rods usedfor the production of transplutonium elements; however, otherexperiments can be irradiated in any of these positions. A similartarget capsule configuration can be used in numerous applications. Athird type of target is designed to house up to nine 2 inch long isotopeor materials irradiation capsules that are similar to the rabbit facility

capsules. The use of this type of irradiation capsule simplifiesfabrication, shipping, and post-irradiation processing which translates to a cost savings for the experime

Target irradiation capsules of each type must be designed such that they can be adequately cooled by thcoolant flow available outside the target-rod shrouds. Excessive neutron poison loads in experiments inpositions are discouraged because of their adverse effects on both transplutonium isotope production ratfuel cycle length. Such experiments require careful coordination to ensure minimal effects on adjacentexperiments, fuel cycle length, and neutron scattering beam brightness. Two positions are now availablinstrumented target experiments: positions E3 and E6.
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Peripheral Target Positions

Six peripheral target positions (PTPs) are provided for experiments located at the outer radial edge of thtrap. Fast-neutron fluxes in these positions are the highest available to experiments in the reactor, althousteep radial gradient in the thermal-neutron flux exists at this location.

Like the target positions, a type of PTP capsule is available that houses up to nine 2 inch long isotope omaterials irradiation capsules that are similar to the rabbit facility capsules. The use of this type of irradicapsule simplifies fabrication, shipping, and post-irradiation processing which translates to a cost savingthe experimenter.

PTP irradiation capsules of each type must be designed such that they can be adequately cooled by thecoolant flow available. Typical experiments contain a neutron poison load equivalent to that associated 200 g of aluminum and 35 g of stainless steel distributed uniformly over a 20-in. (50.8-cm) length. PTPexperiments containing neutron poison loads in excess of that described are discouraged because of theadverse effects on isotope production rates, fuel cycle length, and fuel element power distribution.

Hydraulic Tube Facility

The HFIR hydraulic tube (HT) facility provides the ability to irradiate materials for durations less than standard ~23 day HFIR fuel cycle, which is ideal for the production of short half-life medical isotopes require retrieval on demand. The system consists of the necessary piping, valves, and instrumentation toshuttle a set of 2 -inch long aluminum capsules (called rabbits) between the capsule loading station aflux trap in the reactor core. The capsule loading station is located in the storage pool adjacent to the revessel pool. A full facility load consists of nine vertically stacked capsules.

Normally, the heat flux from neutron and gamma heating at the surface of the capsule is limited to 74,0Btu/h-ft (2.3 x 105 W/m). Furthermore, the neutron poison content of the facility load is limited such threactor cannot be tripped by a significant reactivity change upon insertion and removal of the samples.

Large Removable Beryllium Reflector Facilities

Eight large diameter irradiation positions are located in the removable beryllium (RB) near the control rThese facilities are designated as RB-1A and -1B, RB-3A and -3B, RB-5A and -5B, and RB-7A and These are generally referred to as the RB* positions. The vertical centerline of these facilities is locatedin. (27.31 cm) from the vertical centerline of the reactor and they are lined with a permanent aluminum having an inside diameter of 1.811 in. (4.6 cm). These facilities are designed for either instrumented or instrumented experiments. The instrumented capsule design can also employ sweep or cooling gases asnecessary. Instrument leads and access tubes are accommodated through penetrations in the upper shrouflange and through special penetrations in the pressure vessel hatch. When not in use, these facilities coberyllium or aluminum plugs. Because of their close proximity to the fuel, RB* experiments are carefulreviewed with respect to their neutron poison content, which is limited because of its effect on fuel elempower distribution and fuel cycle length. These positions can accommodate (i.e., shielded) experiments,making them well suited for fusion materials irradiation. Uses for the RB* facilities have included theproduction of radioisotopes; High Temperature Gas-Cooled Reactor (HTGR) fuel irradiations; and theirradiation of candidate fusion reactor materials. The later type of experiment requires a fast neutron flusignificant fast flux is present in addition to the thermal flux. For this application the capsules are placed


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liner containing a thermal neutron poison for spectral-tailoring. These experiments are carefully reviewerespect to their neutron poison content and limited to certain positions to minimize their effect on adjaceneutron scattering beam tubes.

Small Removable Beryllium Facilities

Four small diameter irradiation positions are located in the removable beryllium (RB) near the control rThese facilities are designated as RB-2, RB-4, RB-6, and RB-8. The vertical centerline of these facilit ilocated 10.37 in. (26.35 cm) from the vertical centerline of the reactor and have an inside diameter of 0(1.27 cm). The small RB positions do not have an aluminum liner like the RB* facilities. When not in these positions contain beryllium plugs. The use of these facilities has been primarily for the productionradioisotopes. The neutron poison content limits and the available pressure drop requirements for experin these facilities is the same as in the RB* facilities previously discussed.

Control-Rod Access Plug Facilities

Eight 0.5-in. (1.27-cm) diameter irradiation positions are located in the semipermanent reflector. The

semipermanent reflector is made up of eight separate pieces of beryllium, four of which are referred to control-rod access plugs. Each control-rod access plug contains two unlined irradiation facilities, designCR-1 through CR-8. Each of these facilities accommodates an experiment capsule similar to those usedsmall removable beryllium facilities. The vertical centerlines of all control-rod access plug irradiation faare located 12.68 in. (32.2 cm) from the vertical centerline of the reactor. Only non-instrumented expercan be irradiated in these facilities. When not in use, these facilities contain beryllium plugs. A pressureof 10 psi (6.89 x 104 Pa) at full system flow is available to provide primary system coolant flow for cooexperiments.

Small Vertical Experiment Facilities

Sixteen irradiation positions located in the permanent reflector are referred to as the small vertical experfacilities (VXF). Each of these facilities has a permanent aluminum liner having an inside diameter of 1in. (4.02 cm). The facilities are located concentric with the core on two circles of radii 15.43 in. (39.2 c17.36 in. (44.1 cm), respectively. Those located on the inner circle (11 in all) are referred to as the inneVXFs. Those located on the outer circle (five in all) are referred to as the outer small VXFs. Normally,instrumented experiments are irradiated in these facilities. VXF-7 is dedicated to one of the pneumaticirradiation facilities that supports the Neutron Activation Analysis Laboratory and is unavailable for othA pressure drop of approximately 100 psi (6.89 x 105 Pa) at full system flow is available to provide primasystem coolant flow for cooling experiments. When not in use, these facilities may contain a beryllium aluminum plug or a flow-regulating orifice and no plug. Large neutron poison loads in these facilities ano particular concern with respect to fuel element power distribution perturbations or effects on fuel cylength because of their distance from the core; however, experiments are carefully reviewed with respectheir neutron poison content, which is limited to minimize their effect on adjacent neutron scattering beatubes.

Large Vertical Experiment Facilities


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High Flux Isotope Reactor Cherenkradiation

Six irradiation positions located in the permanent reflector are referred to as the large vertical experimenfacilities. These facilities are similar in all respects (as to characteristics and capabilities) to the small verexperiment facilities described in the preceding section except for location and size. The aluminum linethe large VXFs have an inside diameter of 2.834 in. (7.20 cm), and the facilities are located concentric the core on a circle of radius 18.23 in. (46.3 cm). When not in use, these facilities contain beryllium oraluminum plugs. Large neutron poison loads in these facilities are of no particular concern with respectelement power distribution perturbations or effects on fuel cycle length because of their distance from thcore; however, experiments are carefully reviewed with respect to their neutron poison content, which ilimited to minimize their effect on adjacent neutron scattering beam tubes.

Slant Engineering Facilities

Provision has been made for installation of up to two engineering facilities to provide additional positioexperiments. These facilities consist of 4-in. (10.16-cm)-O.D. tubes that are inclined upward 49 fromhorizontal. The inner ends of the tubes terminate at the outer periphery of the beryllium. The upper endtubes terminate at the outer face of the pool wall in an experiment room one floor above the main beamOne of the engineering facilities houses the PT-2 pneumatic tube, which was installed in 1986.

Gamma Irradiation Facility

Overview

The HFIR Gamma Irradiation Facility is an experiment facility in theHigh Flux Isotope Reactor designed to irradiate materials withgamma radiation from the spent fuel elements in the HFIR loadingstation in the clean pool. The Gamma Irradiation Facility Chamber isa stainless steel chamber made of 0.065 wall thickness tubing tomaximize the internal dimensions of chamber to accommodate as/large as possible samples and still fit inside the cadmium post of thespent fuel loading station positions. The interior chamber isapproximately 3 inside diameter and will accommodate samples upto 25 inches (640 mm) long.

There are two configurations for the chamber assembly, with the only difference being the plugs. Theuninstrumented configuration has a top plug which is used for installation of the samples and to supporinert gas lines and maintain a leak tight environment while under water. The instrumented configurationchamber extension above the chamber and an umbilical to permit inert gas lines, electrical cables and

instrumentation cables for an instrumented experiment to connect with heater controls and instrumentatitesting equipment in the experiment room.

An inert gas control panel in the experiment room is required to provide inert gas flow and pressure relthe chamber. Inert gas pressure is maintained at approximately 15 psig to assure an leakage from the chwould be from the chamber to the pool and not water in leakage.

Samples in the chamber may be supported from the bottom of the chamber or from the plug (uninstrumconfiguration only).
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Using delayed neutron analysis, we are able to provide an inexpensive, precise, and accurate screening various materials for fissile content. The determination requires only six minutes and features a 15-picodetection limit. Samples of smears, vegetation, soil, rock, plastics, wood, metal, and sand are equallyamenable to delayed neutron analysis. This versatile and speedy tool facilitates International Atomic EnAgency IAEA efforts to establish wide area monitoring and enables individual inspectors to obtain largnumbers of samples in the hopes of finding required evidence. By screening those samples here, the vecosts of destructive analysis are required only for those samples deemed interesting." Delayed neutronanalysis is becoming increasingly useful for these studies.

A recent application involves the irradiation of programmable memory devices that have been coated wsmall amount of a fissile isotope. The fission events induced upon irradiation may be tracked spatially bcomparing the values in memory with those assigned to memory initially; areas of differences are attribdamage caused by the fission events. This work may assist efforts in analysis of microscopic particles thmay contain evidence of undeclared nuclear activities by locating such particles.

Environmental

NAA is well suited for determining about two-thirds of the known elements in geological and biologicmaterials nondestructively. Several projects were facilitated by NAA that otherwise would have been vchallenging or impossible by other methods. Mercury contamination in the Oak Ridge area, baseline solevels for many elements, and uranium isotopic ratio in Oak Ridge area soils and vegetation have all beaccomplished on the medium and large scale. The chemistry and history of Earths moon have beenelucidated by NAA and many different meteorites have been studied here. Trace elements were determanimal bone and tissue for efforts to understand effects of habitat pollution. The fate of the dinosaurs winvestigated by analyzing the element, iridium, in fossilized bone dated near in time to known major meimpacts. Recently, bioremediation strategies have been examined and rates of absorption of heavy elemhave been determined in indigenous plants and animals.

Forensics

Since its inception, NAA has been an outstanding tool for forensic trace element investigations. Bullet and jacket, paint, brass, plastic, hair, and many other materials are often of interest for criminal investigAt ORNL, investigations involving presidents Kennedy and Taylor, investigation of cave vandals, andhomicide investigations have been undertaken. NAA excels at such determinations because it isnondestructive and because there are few sources of error, and all are known and can be estimated. Wenegotiation with Brookhaven National Laboratory scientists to continue their anthropogenic investigatioancient marble and sculpture. Such a partnership follows logically after the permanent shutdown of theBrookhaven reactor.

Isotope Production

Small quantities of various isotopes have been formed in the PT-1 facility over the years. Tracers for anstudies, radiolabeled pharmaceuticals, cancer treatment trial sources, and sources in support of materialsstudies have been prepared inexpensively. The PT-1 facility represents the quickest access to the reactoroften the lowest cost for low-quantity isotope production. Recently, gamma densitometry sources compof 169Yb were prepared and may be prepared on-demand for the foreseeable future.
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Ultra-T race Metrology

Many elements may be easily and precisely measured at the parts-per-trillion level using NAA. We assisprivate corporations with applied research into the properties of fiber optic starting materials and theirrelationship to trace element concentration and found that breakage frequency does depend on theconcentration of certain elements. Diamond and diamond films have been analyzed for ultra-trace impurand our determinations were the first to be reported on bulk synthetic diamond. Most recently, we deter

uranium and thorium in organic scintillator at the 1e-15 g/g level, a feat possible because of our highestavailableflux. The scintillator is to be used in a neutrino detection project in Japan that requires materiafree fromnatural radioactivity as possible.

Materia ls Irradiation

The combined effects of neutron and gamma radiation on materials are of interest for advanced materialresearch, fusion energy research, and for production of hardened components and systems. Many exaof materials irradiation activities are worthy of mention. A most recent example is the dose responseinvestigation of dichroic mirror ceramic materials for the fusion energy research program. The PT-1 and

facilities are well suited to fill the niche between the very high fluxes in the HFIR target region and the lower ones in the beam tubes.

Refer ences

1. ^ Data suggest world record at Oak Ridge reactor (http://www.knoxnews.com/news/2007/nov/26/data-suggeworld-record-oak-ridge-reactor/), By Frank Munger, Knoxville News Sentinel , November 26, 2007

2. ^ "HFIR Technical Paramters" (http://neutrons.ornl.gov/hfir/hfir_technical_parameters.shtml). Oak Ridge NLaboratory.

3. ^ N. Xoubi and R. T. Primm III (2004). "Modeling of the High Flux Isotope Reactor Cycle 400"(http://www.ornl.gov/info/reports/2005/34456057865571.pdf).Oak Ridge Technical Report ORNL/TM-2004/251

Exter nal links

Bryan, Chris (October 2011). "High Flux Isotope Reactor" (http://neutrons.ornl.gov/facilities/HFIOa k Ridge National Laboratory Research Reactors Division . United States Department of Energy.Retrieved October 26, 2011.

"Aerial view of HFIR site" (http://maps.google.com/maps?q=Oak+Ridge,+TN&t=k&hl=en&ll=35.918128,-84.303975&spn=0.01173,0.025663&om=1). GoMaps. 2006. Retrieved April 20, 2006."The HFIR Facility at Oak Ridge National Lab"(http://web.archive.org/web/20070629231331/http://neutrons.ornl.gov/facilities/facilities_hfir.shtmOak Ridge National Laboratory. 2007. Archived from the original(http://neutrons.ornl.gov/facilities/facilities_hfir.shtml) on June 29, 2007. Retrieved June 23, 2007
http://neutrons.ornl.gov/facilities/facilities_hfir.shtmlhttp://web.archive.org/web/20070629231331/http://neutrons.ornl.gov/facilities/facilities_hfir.shtmlhttp://maps.google.com/maps?q=Oak+Ridge,+TN&t=k&hl=en&ll=35.918128,-84.303975&spn=0.01173,0.025663&om=1http://neutrons.ornl.gov/facilities/HFIR/http://www.ornl.gov/info/reports/2005/34456057865571.pdfhttp://neutrons.ornl.gov/hfir/hfir_technical_parameters.shtmlhttp://en.wikipedia.org/wiki/Knoxville_News_Sentinelhttp://www.knoxnews.com/news/2007/nov/26/data-suggest-world-record-oak-ridge-reactor/


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