Environmental Problems, Their Causes, and Sustainability 1

eactor core did not melt down and no human liveswere lost. Also, concern has risen about the vulnerabilityof nuclear power plants to terrorist attacks after theevents of September 11, 2001, in the United States.Experts are especially concerned about the vulnerabilityof poorly protected and intensely radioactive spentfuel rods stored in pools or casks outside of reactorbuildings.What Are the Advantages and Disadvantagesof the Conventional Nuclear Fuel Cycle?Better than Coal but Much More Costly andVulnerable to Terrorist AttackAdvantagesLarge fuelsupplyLowenvironmentalimpact (withoutaccidents)Emits 1/6 as muchCO 2 as coalModerate landdisruption andwater pollution(withoutaccidents)Moderateland useLow risk ofaccidentsbecause ofmultiplesafety systems(except in 35poorly designedand run reactorsin former SovietUnion andeastern Europe)Trade-OffsConventional Nuclear Fuel CycleDisadvantagesHigh cost even withlarge subsidiesLow net energy yieldHigh environmentalimpact (with majoraccidents)Catastrophicaccidents canhappen (Chernobyl)No widelyacceptable solutionfor long-term storageof radioactivewastes anddecommissioningworn-out plantsSubject to terroristattacksSpreads knowledgeand technology forbuilding nuclearweaponsFigure 17-26 Trade-offs: advantages and disadvantages ofusing the conventional nuclear fuel cycle (Figure 17-24) to produceelectricity. Pick the single advantage and disadvantagethat you think are the most important.The nuclear fuel cycle has a fairly low environmentalimpact and a very low risk of an accident, but costsare high, radioactive wastes must be stored safely forthousands of years, and facilities are vulnerable toterrorist attack.Figure 17-26 lists the major advantages and disadvantagesof the conventional nuclear fuel cycle. Usingnuclear power to produce electricity has some importantadvantages over coal-burning power plants (Figure17-27).Some proponents of nuclear power in the UnitedStates claim it will help reduce dependence on importedoil. But other analysts point out that nuclearpower has little effect on U.S. oil use because burningoil typically produces only 2–3% of the electricity inthe United States. The major use for oil is to producegasoline and diesel fuel for transportation, whichwould not be affected by increasing the use of nuclearpower to produce electricity.Proponents say we should increase the use of nuclearpower because its use does not release the greenhousegas carbon dioxide into the atmosphere. It istrue that nuclear power plants do not release carbondioxide. However, the nuclear fuel cycle does releasethis gas into the atmosphere, although emissions areless per unit of energy than burning fossil fuels (Figure17-16).Because of multiple built-in safety features, the riskof exposure to radioactivity from nuclear power plantsin the United States and most other developed countriesis extremely low. However, a partial or completemeltdown or explosion is possible, as the Chernobyland Three Mile Island accidents have taught us.The U.S. Nuclear Regulatory Commission (NRC)estimates there is a 15–45% chance of a complete coremeltdown at a U.S. reactor during the next 20 years.The NRC also found that 39 U.S. reactors have an 80%chance of failure in the containment shell from a meltdownor an explosion of gases inside containmentstructures.Throughout the world, nuclear scientists and governmentofficials urge the shutdown of 35 poorly designedand poorly operated nuclear reactors in somerepublics of the former Soviet Union and in easternEurope. This is unlikely without economic aid fromdeveloped countries.In the United States, there is widespread publicdistrust of the ability of the NRC and the Departmentof Energy (DOE) to enforce nuclear safety in commercial(NRC) and military (DOE) nuclear facilities. In1996, George Galatis, a respected senior nuclear engineer,said, “I believe in nuclear power but after seeingthe NRC in action I’m convinced a serious accident isnot just likely, but inevitable. ... They’re asleep at thewheel.”Concerns about the safety of some U.S. nuclearpower plants grew in 2002 when inspectors found thatleaking boric acid had eaten a softball-size holethrough nearly the entire reactor lid at a nuclear plantnear Toledo, Ohio. The only thing preventing a ruptureof the high-pressure reactor vessel and a possible370 CHAPTER 17 Nonrenewable Energy Resources