Nuclear Technology  

Nuclear Technology in General > s.a. nuclear physics.
* Radioactivity, uses: Paper is gauged at a paper mill, and band-aids are sterilized, with a radioactive source.
@ Nuclear weapons: issue PT(98)mar [banning nuclear tests]; Reed AJP(05)sep, AJP(11)feb [Manhattan Project, RL]; Bernstein AJP(11)may [1940 memoir by Otto Frisch and Rudolf Peierls].
@ Nuclear power: Flanagan AJP(10)oct [resource letter]; > s.a. below.
@ Related topics: Meshik SA(05)nov [ancient Oklo reactor].

NMR / MRI
* Idea: Magnetic Resonance Imaging (or MRI) machines have only been in use since 1977, but they have revolutionized the ability of doctors to visualize the inner workings of the human body; An MRI machine is basically an enormous magnet with a hollow tube in the middle; The part of the patient that is to be imaged is placed in the center of the magnetic field, which causes most of atoms in their cells to line up along the axis of the tube; The area is then bombarded with radio waves, and some of the atoms are knocked off axis; As they return to alignment, they release energy that is picked up by sensitive detectors; Sophisticated computer programs convert this data into 3D images of the tissue in question.
* Status: 1999, Achieved for gases, as opposed to liquids, and applied to the study of porous sandstone; Later will apply to medicine [@ news pn(99)oct].
@ References: Wolfson 91; Mamin et al NaN(07) + pw(07)apr [90-nm resolution].

Hot Fusion {& Rex Gandy, Auburn U, colloquium 14.10.1997.}
* Reactions: First generation will use D + T = α + n, easier to get although T is radioactive.
* Inertial confinement: Multiple laser/particle beams converge on a target that compresses and heats up a D-T mixture; Works in H bombs, not much known about controlled lab conditions; n = 1024/cm3, τ = 10–10 s.
* Magnetic confinement: Open traps (magnetic mirrors, they leak); Closed traps (tori with helical nested field lines), Tokamak (USSR 1950s, current in plasma) and Stellarator (USA 1950s, helical coils); n = 1014 cm–3 (10–3 atm!), τ = 1 s.
* Requirement: For D+T, need ≥ 1014 cm–3 · s, n = number density, τ = confinement time (determined mostly by e heat loss, not totally understood).
* Applications: Commercial electric energy; military.
* Status: 1997, largest is JET (Joint European Torus) Tokamak, near Oxford, UK; Produced 13 MW peak (50% of input) [@ Nat(97)nov]; 2002, Claims of tabletop d-d fusion by sonoluminescent bubbles [@ Taleyarkhan et al Sci(02)mar + pn(02)mar; news pn(04)mar]; 2006, ITER fusion reactor gets final approval, completion expected by 2015; 2009, The 2018 start date for ITER is not realistic; 2012, Further delays for the €15 billion ITER effort; 2013, Despite NIF's failure to achieve ignition, an independent review panel says the technology holds enough promise to continue research; 2014, ITER is consuming most of the US fusion-energy budget, looks set to cost as much as US$50G — about 10 times the original estimate — and will not begin its first fuelled experiments before 2027, but some upstart companies have raised money to try alternative designs.
* Future: 1997, Stellarators on the rise; ITER (International Thermonuclear Experimental Reactor) planned.
@ Status: Bishop PT(64)mar; Lindl et al PT(92)sep [inertial confinement]; Alejandre PW(96) [stellarator]; Fodor et al PT(96)dec, PT(97)jan, PT(97)mar [status, letters]; Hazeltine & Prager PT(02)jul [plasma confinement]; Boozer RMP(04) [magnetic confinement]; Hoang & Jacquinot pw(04)jan; Pitts et al pw(06)mar [+ ed pw(06)mar]; news pw(06)nov [ITER approved]; news PT(08)may [Compact Stellarator experiment canceled]; news Nat(09)nov [ITER 2018 start date not realistic]; Moyer SA(10)mar; news sp(12)mar, pppl(12)apr [breakthrough]; news pt(12)oct [NIF's failure to achieve ignition and emphasis shift]; news Nat(12)oct [further ITER delays]; news ns(13)feb; news sn(13)apr [ignition fails at NIF]; Rose Phy(14) [encouraging signs]; news pt(14)jun and sci(15)may [Senate panel orders US withdrawal from ITER]; news nat(14)jul [alternative fusion technologies]; news sci(15)may [spherical tokamak]; blog pt(15)aug [consequences of the 1960s US decision to abandon its lead in reactor design]; news tn(16)feb [EAST breakthrough, H at 50 MK for 102 s].
@ Power plants: Lake et al SA(02)jan; Wald SA(03)mar [dismantling].
@ Books: Herman 91; Wilhelmsson 00 [r pw(00)may]; Harms et al 00; Chen 11 [and energy issues, r PT(12)feb]; NRC report 13 [prospects].

Cold Fusion
* Status: 1989, Claims by Fleischmann and Pons; Not reproduced by others and later discredited; 2010, There is a community of scientists still trying to demonstrate a reproducible effect, so far without success (instead of "cold fusion" they now call the field "condensed-matter nuclear science" or "low-energy nuclear reaction"); 2011, New claim by Italian physicist and inventor Andrea Rossi.
@ Status: Pool Sci(89)mar, Sci(89)apr, Sci(89)apr, Sci(89)apr, Sci(89)may, Sci(89)jun, Sci(89)jul, Sci(89)oct, Sci(89)oct, Sci(89)nov; Sci(89)dec; Maddox Nat(89)jul; Chatterjee Nat(89)nov; Cohen & Davies Nat(89)nov; Lindley Nat(90)mar; PW(90)feb, p35; NS(91)jan19; news pw(99)mar; news pt(11)nov [comments in the press on Rossi's claim].
@ General references: Brown JRNCL(89) [refs]; Peat 89; Close 90; Huizenga 92; Taubes 93; Sheldon CP(08) [overview].


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