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Neutron Reflector |  Nuclear Physics | class 12 physics subject notes lectures|CBSE|IITJEE|NEET
Neutron Reflector | Nuclear Physics | class 12 physics subject notes lectures|CBSE|IITJEE|NEET
Published: 2016/11/18
Channel: Wikitechy School
Perfect Neutron Reflector - Computer Simulation (for Susan)
Perfect Neutron Reflector - Computer Simulation (for Susan)
Published: 2012/07/18
Channel: Peter Alaric
Neutron reflector
Neutron reflector
Published: 2017/08/30
Channel: Search Engine
Neutron reflector
Neutron reflector
Published: 2017/04/03
Channel: Search Engine
Beryllium - A LIGHT Metal that REFLECTS NEUTRONS!
Beryllium - A LIGHT Metal that REFLECTS NEUTRONS!
Published: 2016/12/24
Channel: Thoisoi2 - Chemical Experiments!
SNAP-10A: First Nuclear Reactor In Space 1965 Atomic Energy Commission (AEC)
SNAP-10A: First Nuclear Reactor In Space 1965 Atomic Energy Commission (AEC)
Published: 2016/11/24
Channel: Jeff Quitney
Feed the beast- Mindcrack: Ep. 118 -Neutron Reflectors Are Breaking Bad
Feed the beast- Mindcrack: Ep. 118 -Neutron Reflectors Are Breaking Bad
Published: 2014/01/19
Channel: SuperPurplepaint
FTB 5 - The BEST Nuclear Reactor Setup - The Most Iridium I
FTB 5 - The BEST Nuclear Reactor Setup - The Most Iridium I've Used
Published: 2013/07/21
Channel: SonicWaffles
Rarpack Episode 12: I fixed the reflectors!
Rarpack Episode 12: I fixed the reflectors!
Published: 2014/10/17
Channel: Robert Arblaster
Neutron moderator
Neutron moderator
Published: 2014/11/15
Channel: Audiopedia
Mock Up Of Nuclear Bomb In A Suitcase - James Burke (1978)
Mock Up Of Nuclear Bomb In A Suitcase - James Burke (1978)
Published: 2017/05/18
Channel: Peter Borenius
Advanced Test Reactor ~ 1965 US Atomic Energy Commission; AEC Nuclear Reactor Research
Advanced Test Reactor ~ 1965 US Atomic Energy Commission; AEC Nuclear Reactor Research
Published: 2017/06/05
Channel: Jeff Quitney
Idea: Complementary Transmutation Nuclear Reactor
Idea: Complementary Transmutation Nuclear Reactor
Published: 2012/07/13
Channel: Peter Alaric
What is NUCLEAR REACTOR COOLANT? What does NUCLEAR REACTOR COOLANT meaning
What is NUCLEAR REACTOR COOLANT? What does NUCLEAR REACTOR COOLANT meaning
Published: 2017/08/29
Channel: The Audiopedia
A quick look at Neutron Reflectometry at Institut Laue-Langevin in Grenoble, France
A quick look at Neutron Reflectometry at Institut Laue-Langevin in Grenoble, France
Published: 2016/06/07
Channel: PENN REACT YouTube
Greening of Nuclear - Fission Energy
Greening of Nuclear - Fission Energy
Published: 2016/07/28
Channel: Microsoft Research
Nuclear Reactor - Understanding how it works | Physics Elearnin
Nuclear Reactor - Understanding how it works | Physics Elearnin
Published: 2013/04/23
Channel: Elearnin
Journal of Applied Physics : Boron carbide coatings for neutron detection probed by x-rays, ions...
Journal of Applied Physics : Boron carbide coatings for neutron detection probed by x-rays, ions...
Published: 2015/01/23
Channel: ScienceVio
Neutrons_Cadmium.avi
Neutrons_Cadmium.avi
Published: 2009/11/15
Channel: Carl Willis
ThruNite Neutron 2C V3 2017 Review
ThruNite Neutron 2C V3 2017 Review
Published: 2017/05/31
Channel: WeaponCollector
Response to iSuperiorReviews Questions
Response to iSuperiorReviews Questions
Published: 2013/05/10
Channel: antiprotons
First Test
First Test
Published: 2014/11/24
Channel: Tim Flaspoler
Neutron Source |  Nuclear Physics |class 12 physics subject notes lectures|CBSE|IITJEE|NEET
Neutron Source | Nuclear Physics |class 12 physics subject notes lectures|CBSE|IITJEE|NEET
Published: 2016/11/18
Channel: Wikitechy School
THE ADVANCE TEST REACTOR  ATR  NUCLEAR REACTOR 75614
THE ADVANCE TEST REACTOR ATR NUCLEAR REACTOR 75614
Published: 2015/08/19
Channel: PeriscopeFilm
The brand new Neutron Reflectivity Simulator in Eclipse ICE and what it took to make it
The brand new Neutron Reflectivity Simulator in Eclipse ICE and what it took to make it
Published: 2015/11/09
Channel: Eclipse Foundation
Telescopes: Crash Course Astronomy #6
Telescopes: Crash Course Astronomy #6
Published: 2015/02/19
Channel: CrashCourse
Boron as a neutron poison
Boron as a neutron poison
Published: 2011/04/03
Channel: Rohan Mishra
Beryllium oxide - The Russian Hahn David
Beryllium oxide - The Russian Hahn David's channel
Published: 2012/09/20
Channel: ruhahn
Optimal routing vs. Route Reflector VNF - reconcile the fire with water
Optimal routing vs. Route Reflector VNF - reconcile the fire with water
Published: 2015/10/08
Channel: TeamNANOG
Minecraft Industrial Craft 2 Microcycle Nuclear Reactor Design(Generator, Breeder)
Minecraft Industrial Craft 2 Microcycle Nuclear Reactor Design(Generator, Breeder)
Published: 2013/11/20
Channel: Kcuziri
Minecraft 1.4.7 Industrialcraft 2 Modreview/Tutorial Deutsch/German Crafting/Erklärung AKW Teil 3
Minecraft 1.4.7 Industrialcraft 2 Modreview/Tutorial Deutsch/German Crafting/Erklärung AKW Teil 3
Published: 2013/08/06
Channel: Zaimän Zockt
How an Atom Bomb works*Nuclear Fission Chain Reaction*Concept Schools
How an Atom Bomb works*Nuclear Fission Chain Reaction*Concept Schools
Published: 2015/08/30
Channel: DOLL1789MarshalDhody
First US Commercial Nuclear Reactor: "Atomic Power at Shippingport" circa 1958 AEC-Westinghouse
First US Commercial Nuclear Reactor: "Atomic Power at Shippingport" circa 1958 AEC-Westinghouse
Published: 2012/09/17
Channel: Jeff Quitney
Best First Telescope for Astronomy
Best First Telescope for Astronomy
Published: 2017/06/27
Channel: Deep Astronomy
Nuclear Reactor Physics Basics | MEPhIx on edX
Nuclear Reactor Physics Basics | MEPhIx on edX
Published: 2017/03/22
Channel: edX
SSC scientific assistant exam physics Notes-31(NUCLEAR FISSION,FUSSION REACTOR)
SSC scientific assistant exam physics Notes-31(NUCLEAR FISSION,FUSSION REACTOR)
Published: 2017/09/23
Channel: SUCCESS FLOOR
The Missing Nickelodeon Movie - Internet Mysteries - GFM (The Hunt for Cry Baby Lane)
The Missing Nickelodeon Movie - Internet Mysteries - GFM (The Hunt for Cry Baby Lane)
Published: 2017/02/21
Channel: TheGamerFromMars
FTB Infinity lite 1.10, 0060 3 - IndustrialCraft 2; Molecular Transformer#2
FTB Infinity lite 1.10, 0060 3 - IndustrialCraft 2; Molecular Transformer#2
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Channel: Franz Pansen
Top 5 Telescopes for Amateur Astronomy Under $500
Top 5 Telescopes for Amateur Astronomy Under $500
Published: 2017/11/08
Channel: Deep Astronomy
TekkitPedia Episodio 10 - IC2 - Giochicchiando con il Nuclear Reactor e i suoi Components
TekkitPedia Episodio 10 - IC2 - Giochicchiando con il Nuclear Reactor e i suoi Components
Published: 2013/03/27
Channel: Luscha42
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What Are The Control Rods In A Nuclear Reactor Made Of?
Published: 2017/08/23
Channel: Obu Obu
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Published: 2016/08/11
Channel: ANSTOVideos
Nuclear Fission and Fusion
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Published: 2015/09/10
Channel: SliderBase
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CANDU Moderator Flow Studies - James Strack - McMaster University
Published: 2016/03/08
Channel: NSERCTube
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Published: 2016/10/17
Channel: Mike Sugiyama Jones
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4 vs 5 - DUOQ DIA 5 - Es posible!!
Published: 2015/07/14
Channel: alexelcapo
Thrunite Catapult V3 XML Led (Smooth Reflector)
Thrunite Catapult V3 XML Led (Smooth Reflector)
Published: 2011/04/05
Channel: SEXWAX2902
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Published: 2016/04/16
Channel: Pablo Marroquin
Is The Universe Infinite?
Is The Universe Infinite?
Published: 2017/03/03
Channel: The Science Asylum
(1/2) Astronomers Discover Most Massive Neutron Star Yet Known - Part I: Discovery
(1/2) Astronomers Discover Most Massive Neutron Star Yet Known - Part I: Discovery
Published: 2010/10/27
Channel: djxatlanta
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WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
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A neutron reflector is any material that reflects neutrons. This refers to elastic scattering rather than to a specular reflection. The material may be graphite, beryllium, steel, tungsten carbide, or other materials. A neutron reflector can make an otherwise subcritical mass of fissile material critical, or increase the amount of nuclear fission that a critical or supercritical mass will undergo. Such an effect was exhibited twice in accidents involving the Demon Core, a subcritical plutonium pit that went critical in two separate fatal incidents when the pit's surface was momentarily surrounded by too much neutron reflective material.

Nuclear reactors[edit]

In a uranium graphite chain reacting pile, the critical size may be considerably reduced by surrounding the pile with a layer of graphite, since such an envelope reflects many neutrons back into the pile.

To obtain a 30-year life span, the SSTAR nuclear reactor design calls for a moveable neutron reflector to be placed over the column of fuel. The reflector's slow downward travel over the column would cause the fuel to be burned from the top of the column to the bottom.

A reflector made of a light material like graphite or beryllium will also serve as a neutron moderator reducing neutron kinetic energy, while a heavy material like lead or lead-bismuth eutectic will have less effect on neutron velocity.

In power reactors, a neutron reflector reduces the non-uniformity of the power distribution in the peripheral fuel assemblies, reduces neutron leakage and reduces a coolant flow bypass of the core. By reducing neutron leakage, the reflector increases reactivity of the core and reduces the amount of fuel necessary to maintain the reactor critical for a long period. In light-water reactors, the neutron reflector is installed for following purposes[1]:

  • The neutron flux distribution is “flattened“, i.e., the ratio of the average flux to the maximum flux is increased. Therefore reflectors reduce the non-uniformity of the power distribution.
  • Because of the higher flux at the edge of the core, there is much better utilization in the peripheral fuel assemblies. This fuel, in the outer regions of the core, now contributes much more to the total power production.
  • The neutron reflector scatters back (or reflects) into the core many neutrons that would otherwise escape. The neutrons reflected back into the core are available for chain reaction. This means that the minimum critical size of the reactor is reduced. Alternatively, if the core size is maintained, the reflector makes additional reactivity available for higher fuel burnup. The decrease in the critical size of core required is known as the reflector savings.
  • Neutron reflectors reduce neutron leakage i.e. to reduce the neutron fluence on a reactor pressure vessel.
  • Neutron reflectors reduce a coolant flow bypass of a core.
  • Neutron reflectors serve as a thermal and radiation shield of a reactor core.

Nuclear weapons[edit]

A similar envelope can be used to reduce the critical size of a nuclear weapon, but here the envelope has an additional role: its very inertia delays the expansion of the reacting material. For this reason such an envelope is often called a tamper. The weapon tends to fly to bits as the reaction proceeds and this tends to stop the reaction, so the use of a tamper makes for a longer-lasting, more energetic, and more efficient explosion. The most effective tamper is the one having the highest density; high tensile strength is irrelevant because no material remains intact under the extreme pressures of a nuclear weapon. Coincidentally, high-density materials are excellent neutron reflectors. This makes them doubly suitable for nuclear weapons. The first nuclear weapons used heavy uranium or tungsten carbide tamper-reflectors.

On the other hand, a heavy tamper necessitates a larger high-explosive implosion system. The primary stage of a modern thermonuclear weapon may use a lightweight beryllium reflector, which is also transparent to X-rays when ionized, allowing the primary's energy output to escape quickly to be used in compressing the secondary stage.

While the effect of a tamper is to increase efficiency, both by reflecting neutrons and by delaying the expansion of the bomb, the effect on the critical mass is not as great. The reason for this is that the process of reflection is time-consuming. By the time reflected neutrons make it back into the core, several generations of the chain reaction have passed, meaning the contribution from the older generation is a tiny fraction of the neutron population.

See also[edit]

External links[edit]

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