Known Nuclides

http://sutekh.nd.rl.ac.uk/CoN/

Nuclear Fission

http://hyperphysics.phy-astr.gsu.edu/hbase/nucene/fission.html

Fission products

http://www.euronuclear.org/info/encyclopedia/f/fissionproducts.htm

http://en.wikipedia.org/wiki/Fission_products

Nuclear Reactors (LWR’s)

http://reactor.engr.wisc.edu/power.html

Boiling water reactor (BWR) Pressurized water reactor (PWR)66% of US reactors are this type

American Nuclear Plants

http://www.nrc.gov/info-finder/reactor/

Radioactive wastes

http://www.uic.com.au/nip09.htm

Nuclear Waste depots

http://en.wikipedia.org/wiki/Radioactive_waste

Yucca Mountain

http://www.ocrwm.doe.gov/ymp/about/why.shtml

Nuclear Plants world wide

http://en.wikipedia.org/wiki/Radioactive_waste

Nuclear Fusionhttp://www.nuc.berkeley.edu/fusion/fusion.html

The reaction shown is the easiest to use, but D-D is also possible and is whatwe discussed in class, simply because it is easier to get the fuel and the mathis a bit easier. 2*MD= 4.027106 amu vs. 3He + p = (3.0160293+1.007825) amu + ~2MeV or 3H + n = (3.0160492+1.008665) amu + ~3MeV

NOTE: 3He and p are stable 3H has a half-life of 12 years, n of 15 minutes.This process produces no long-lived radioactivity directly, unlike fission.

ITER

http://www.iter.org/index.htm

Proposed 500MWFusion testFacility. First plasma expected2016.

“InternationalThermonuclearExperimental Reactor”

Inertial confinement

http://www.nuc.berkeley.edu/thyd/icf/target.html

Review for Final Exam

• Exam will have roughly 28 questions (i.e. slightly longer than previous exams, but you have much more time).

• Roughly half of the questions will cover material discussed since exam II, the rest will be roughly equally split between material covered on exam I and exam II

• Cover page will be on ONCOURSE some time next week.

Exam Review: Electricity

• Action of a battery, the concept of EMF

• Ohm’s law and power: V=IR P= IV

• Parallel and series circuits

• Faraday’s law and the generation of electricity

• Transformers

• The electric power grid: Generation, transmission, distribution

Summary of wind power

• Power available is roughly:– P=2.8x10-4 D2 v3 kW (D in m, V in m/s)

• i.e. you get much more power at higher wind speeds with larger turbines

• 3-blade turbines are more efficient than multi-blade, but the latter work at lower wind speeds.

• At higher wind speeds you need to “feather” the blades to avoid overloading the generator and gears.

• Typical power turbines can produce 1 -3.5 MW• You still find people question having even this

form of generator near where they live!

• Provide a source of DC electric power where the EMF is provided by absorbed light

• Need to absorb the light– Anti-reflective coating + multiple layers

• Need to get the electrons out into the circuit (low resistance and recombination)– Low disorder helps with both (hence crystal is more efficient than

amorphous)

• Record efficiency of 42.8% was announced in July 2007 (U. Delaware/Dupont).

• Crystalline Si: highest efficiency (typically 15-25%), poorer coverage, bulk material but only the surface contributes, expensive (e.g. NASA).

• Amorphous Si: lower efficiency (5-13%), less stable (can degrade when exposed to sunlight).

Synopsis of Solar Cells

• Chemical energy is converted directly to (DC) electrical energy.

• Similar to battery, but there is an input fuel, you’re not limited to an “on-board” chemical supply.

• Need electrodes, electrolyte, probably catalysts at the electrodes, and perhaps a reformer.

• Different types have different chemistry, electrolyte, operating temperatures, efficiencies, size, and robustness (etc.)

Synopsis of Fuel Cells

• Alkaline Acid– High efficiency (up to 60%), small, pure H2 fuel, very sensitive– Used by NASA (very expensive, so only they can afford it)

• Molten Carbonate– High efficiency (up to 60%), high temp operation (600C), bulky,

robust– Used in back-up generation/ Combined Heat/Power (CHP) modes

(Fuel Cell Energy)• Polymer Electrolyte Membrane (PEM)

– Lower temp operation (<100C), sensitive catalysts/ reformers needed, compact, lower efficiency (35%??)

– Leading candidate for transportation (Ballard)• Solid Oxide Fuel Cells

– Highest efficiency (70%), very high-T operation (1000C)– Still in development, not yet commercially viable

Synopsis of Fuel Cells

Nuclear Energy

• Binding energy of nuclei are MUCH LARGER than that of moelcules– E=mc2

• Radioactivity– Comes from both the primary reactions (especially in fission)

and activation by the neutrons released in the reactions (both).– Half life, decay modes, health hazards

• Fission:– Split a large nucleus into smaller nuclei PLUS 2 or 3 neutrons

after absorption of a SLOW neutron. – Energy release on the order of 0.74MeV/amu of fuel– Lots of such plants exist throughout the world, but there are

problems• Expensive to build (especially in the US)• Safety issues

Nuclear Energy (cont.)

• Waste from nuclear power:– Spent fuel and decommissioned parts are both

radioactive– Short-term issue (proliferation concerns) as well as

long-term• Fusion:

– Combine two light nuclei (typically isotopes of hydrogen) into one (typically He) with release of energy ~0.84MeV/amu (and neutron(s)).

– Fuel “waste” is much easier to deal with (less active, shorter half-lives)

– Decommissioning may be even a bigger problem than with fission