STS 3700 – Lecture 18 - The Public Confronts the Atom
- Nuclear enlistment, risks and costs, public concern
- Majority of reactors worldwide variations on American light water
reactor (LWR) design, Canadian heavy water reactor (HWR)
called the CANDU (Canadian Deuterium Uranium), 400-600MW
- highly enriched uranium fuel, moderator to increase likelihood of
fission
Nuclear Power Basics
- Boiling water LWR’s
- Fuel, moderator
- Fuel: nuclear reactors split atoms, releasing energy & heat
- Uranium isotopes and fission, energy release,U235, U238
- Enrichment: separating isotopes by weight to isolate most
fissionable, gaseous diffusion, expensive, complex, WWII
- Fuel with low-enriched U235 (5%), weapons grade (20-80%),
proliferation risk
- Moderator: neutrons and atoms, spontaneous emission
- Slower neutrons are more likely to cause fission
- Moderator slows down neutrons, fission, moderator leak, the
reaction slows down
- CANDU reactors, heavy water, isotope of hydrogen called
deuterium, neutrons
Waste Concerns
- Nuclear waste, thousands of years
- France: nuclear waste approximately 1.2 kg per person per year,
100kg of toxic industrial waste, 15kg of hospital waste, 3000 kg of
non-toxic industrial waste, and 700kg of agricultural waste
- Uranium mining, waste products, uranium in building
construction, spent uranium shell casings
- Suggested solutions: disposal in space, deep burial (underground
and underwater), mixing waste with glass and sealing it in steel
containers
- Reprocessing, reactors transmute harmful isotopes into shorter
lived materials
- Life span of nuclear waste, thousands of years, human institutions
for management
- Krypton & xenon into atmosphere, iodine and tritium into water
Nuclear Accidents
- 1960’s, probabilistic risk assessment (PRA)
- PRA calculated probability of Maximum Credible Accident
(MCA) over a period of time (e.g. the likelihood of an accident that
would kill 1000’s of people over 1000’s yrs)
- PRA: serious accident very rare, but still possible
- TMI March 28, 1979:
 Confusion over information, malfunctioning valves, core
overheat, hydrogen bubble formation
 TMI accident, unpredictable under PRA standards role of
organizations, personnel and methods taken from fossil
industry
 Technological momentum: experience with large fossil fuel
heating plants dominant when nuclear plants came on line
 Fossil plant, complex tasks and information broken down into
multiple readouts and they are monitored
 Nuclear plant, bewildering amount of information (TMI)
 Capital intensive fossil plants, constant operation to recover
costs, maximum capacity all the time, nuclear adopted this
approach
- Complex systems, small problems, accumulation, larger problems
- Chernobyl, April 25, 1986:
 Improper changes in testing protocols, spike power to burn off
Xenon, this led to meltdown and explosion
 Chernobyl: water absorbed neutrons, loss of water increased
rate of fission
 Heat spike caused steam explosion
- Two accidents: misinformation and deliberate disobedience of
safety protocols
Resistance to Nuclear Power
- Limited resistance to nuclear power in 1950’s, mid to late 1960’s
stronger public demonstrations against nuclear
- Mid 1970’s local protestors, global anti-nuclear movement
- Sit ins, protests, lobbying, flyer and leaflet distribution, public
meetings
- Resistance to nuclear varied by country
- Degree of resistance and development of nuclear
- Resistance to nuclear highest in West Germany, France,
Switzerland and the US, and lowest in the UK, Belgium and
Canada
- Resistance contributed to: safety systems, environmental
assessments, increased security, increased costs