Nuclear Technology

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.
@ References: Wolfson 91.

Hot Fusion {& Rex Gandy, Auburn U, colloquium 14.10.1997.}
* Reactions: First generation will use D + T = + 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, = 10^–10 s.
* Magnetic confinement: Open traps (magnetic mirrors, they leak); Closed traps (tori with helical nested field lines), Tokamak (USSR 1950's, current in plasma) and Stellarator (USA 1950's, helical coils); n = 10¹⁴ cm^–3 (10^–3 atm!), = 1 s.
* Requirement: For D+T, need n 10¹⁴ cm^–3 · s, n = number density, = 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) + pn(02)mar; news pn(04)mar]; 2006, ITER fusion reactor gets final approval, completion expected by 2015.
* Future: 1997, Stellarators on the rise; ITER (International Thermonuclear Experimental Reactor) planned.
@ Status: Lindl et al PT(92)sep [inertial confinement]; Fodor et al PT(96)dec, PT(97)jan, PT(97)mar [status, letters]; Hazeltine & Prager PT(02)jul [plasma 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].
@ Power plants: Lake et al SA(02)jan; Wald SA(03)mar [dismantling].
@ Texts: Herman 91; Wilhelmsson 00 [r pw(00)may]; Harms et al 00.

Cold Fusion
* Status: 1989, Claims by Fleischmann and Pons; Not reproduced by others and later discredited.
@ 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, 35; NS(91)jan19; news pw(99)mar.
@ General references: Brown JRNCL(89) [refs]; Peat 89; Close 90; Huizenga 92; Taubes 93.

Other Nuclear Technology
* 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)RL [Manhattan Project].
@ Related topics: Meshik SA(05)nov [ancient Oklo reactor].

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