Environmental Problems, Their Causes, and Sustainability 1

out the entire rail or truck trip instead of only in urbanareas.For example, a terrorist hidden along a busy highwayor railway or atop an urban building could use ashoulder-mounted missile launcher to fire one or moreantitank missiles that could penetrate the thick wallsof a shipping cask on a truck or train car (Figure 17-29)and release radioactive materials.There is disagreement over the possible effects ofsuch an event. Some analysts say it would spread radioactiveparticles over no more than a 1.6-kilometer(1-mile) radius and that the area and the people affectedcould be decontaminated by being hosed down.Other analysts say the affected area could be five tothirty times that estimate. And if such an event occurredin an urban area, the spreading radioactivitycould cause 300–18,000 fatal cancers, and result in atleast $10 billion in damages. According to a 2002 DOEstudy, in a worst-case scenario such an urban attackcould release enough radioactivity to expose 96,000people and cause 48 fatal cancers.In 2002, the U.S. National Academy of Sciences, incollaboration with Harvard and University of Tokyoscientists, urged the U.S. government to slow downand rethink the nuclear waste storage process. Theycontend that storing spent-fuel rods in dry-storagecasks in well-protected buildings at nuclear plant sitesis an adequate solution for at least 100 years in termsof safety and national security. This would buy time tocarry out more research on this complex problem andto evaluate other sites and storage methods that mightbe more acceptable scientifically and politically.Despite these suggestions and many objectionsfrom scientists and citizens, during the summer of2002 Congress approved Yucca Mountain as the officialsite for storing the country’s commercial nuclearwastes. Opponents want the law repealed. Meanwhile,Nevada is still fighting the project in the courts. Thisstory illustrates how science, politics, and economicscan interact as people attempt to solve a difficult andcontroversial problem.xHOW WOULD YOU VOTE? Should highly radioactivespent fuel be stored in well-protected buildings at nuclearpower plant sites instead of shipping them to a single site forunderground burial? Cast your vote online at http://biology.brookscole.com/miller14.What Can We Do with Worn-out NuclearPlants? A Costly DilemmaWhen a nuclear reactor reaches the end of its usefullife we have to keep its highly radioactive materialsfrom reaching the environment for thousands of years.When a nuclear plant comes to the end of its usefullife, it must be decommissioned. Scientists have proposedthree ways to do this.One is to dismantle the plant and store its largevolume of highly radioactive materials in a high-levelnuclear waste storage facility (Figure 17-28), whosesafety is questioned by a number of scientists.A second approach is to put up a physical barrieraround the plant and set up full-time security for30–100 years before the plant is dismantled. This allowstime for some of the radioactive material to decayto levels that make dismantlement safer. A third optionis to enclose the entire plant in a tomb that must lastand be monitored for several thousand years.Regardless of the method chosen, decommissioningadds to the total costs of nuclear power as an energyoption. So far, only a few plants have been torndown. But doing this cost two to ten times as much asit did to build them. The total estimated costs for decommissioningthe 103 reactors now in operation inthe United States range from $200 billion to $1 trillion.This further decreases the net energy yield of nuclearpower and adds to its already high cost.At least 228 large commercial reactors worldwide(20 in the United States) are scheduled for retirement by2012. However, the Nuclear Regulatory Commissionhas approved extending the life of at least 40 reactors to60 years. Opponents contend that this could increasethe risk of nuclear accidents in aging reactors. In 2003,congressional auditors reported that the owners of almosthalf the nuclear power reactors in the UnitedStates are not setting aside enough money to decommissionthem when they are retired, which will saddletaxpayers with the bill.What Are “Dirty” Radioactive Bombs?A Serious ThreatTerrorists could wrap conventional explosives aroundsmall amounts of various radioactive materials thatare fairly easy to get, detonate such bombs, andcontaminate an area with radioactivity for decades.Since the terrorist attacks in the United States on September11, 2001, there has been growing concern aboutthreats from explosions of so-called dirty bombs. Such abomb consists of an explosive such as dynamite mixedwith or wrapped around some form of radioactive material—anamount that could fit in a coffee cup.Radioactive materials can be stolen from thousandsof poorly guarded and difficult-to-protectsources or bought on the black market. Sources mightbe hospitals that use radioisotopes (such as cobalt-60)to treat cancer, diagnose diseases, and sterilize sometypes of medical equipment. Another source could beuniversity research labs. Some industries also useradioisotopes to detect leaks in underground pipes, irradiatefood, examine mail and other materials, anddetect flaws in pipe welds and boilers. Radioactivematerials such as americium-241 are also found insmoke detectors.http://biology.brookscole.com/miller14375