单项选择题

TEXT B
Tomorrow evening about 20 million Americans will be shown, on their television screens, how easy it is to steal plutonium (钚) and produce "the most terrifying blackmail weapon ever devised" -- a homemade atomic bomb.
They will be told that no commercial nuclear plant in the United States -- and probably in the world -- is adequately protected against a well planned armed attack by terrorists, and that there is enough information on public record to guide a nuclear thief not only to the underground rooms of nuclear plants where plutonium is stored, but also to tell him how the doors of those underground rooms are designed.
The hour-long television programme, "The Plutonium Connection", makes its point by showing how a 20-year-old student of the Massachusetts Institute of Technology in five weeks designed an atomic bomb composed of plutonium and parts from a hardware store.
The young man, whose identity is being kept secret for fear he may be kidnapped by terrorists, is quoted as saying: "I was pretty surprised about how easy it is to design a bomb. When I was working on my design, I kept thinking there’s got to be more to it than this, but actually there isn’t. It’s simple."
The student worked alone, using information he obtained from science libraries open to the public. The television programme, produced for non-commercial stations across the country by a Boston educational station, shows how quantities of other "secret" information are available to anyone.
The Atomic Energy Commission’s public reading room in Washington is described by the narrator as "the first place a bomb-designer would visit when he was planning his plutonium theft. On file there and freely available are the plans of every civilian nuclear installation in the country."
The programme seems certain to create enormous controversy -- not only over the lack of nuclear safeguards, But also over the morality of appointing the student to design a bomb and the wisdom of drawing attention to the ways that a nuclear thief can work.
Even an official of Public Broadcasting System, which is distributing the TV programme, confessed to uneasiness: "It’s a terribly important subject, and people should know about the dangers, but I can’t help wondering if the programme won’t give someone ideas."
"The Plutonium Connection" explains, for example, that the security systems of nuclear plants were all designed to prevent sabotage by perhaps one or agents of some foreign power. But now this appears less of a hazard than the possibility of an attack by an armed band of terrorists with dedicated disregard for their own lives.
The programme discusses two major plutonium reprocessing plants in the US -- one already operating in Oklahoma, one being completed in South Carolina -- neither of which has more than a handful of armed guards to supplement the alarms, fences and gun-detectors that Government security requires. Both are in such remote areas that it would take at least 45 minutes for a sizeable force to be assembled, if there were an attack.
An official of the South Carolina plant -- a joint operation of Allied Chemical, Gulf Oil and Royal Dutch Shell -- admits to television viewers that the "system we’ve designed would probably not prevent" a band of about 12 armed terrorists from entering.
Stealing plutonium is even easier, the programme suggests. Despite constant survey of all materials on the list, there are inevitably particles of plutonium unaccounted for -- about I lb a month at the Oklahoma plant, owned by the KerrMcGee oil company, which in a year adds up to enough to make an atomic bomb. It is suggested that stealing would be even easier if instrument technicians were unscrupulous enough to alter their measuring devices.
The television film also shows radioactive fuel being transported to nuclear processing plants in commercial armoured cars. As safety measure, US drivers of such cars are ordered to contact headquarters by radio telephone every two hours. But the equipment is "cumbersome and unreliable", and in difficult terrain there are radio black out areas.
The programmer ends with a warning from Dr. Theodore Taylor, a former Atomic Energy Commission officer who has long contended that any person of modest technical ability could make an atomic bomb: "If we don’t get this problem under international control within the next five or six years, there is a good chance that it will be permanently out of control."
What is the main theme of the passage