A statistic was misprinted in a letter from Ellyn Weiss, general counsel of the Union of Concerned Scientists, which appeared Saturday on the Free for All page. The sentence should have read: "The NRC's own research shows a 10 percent to 50 percent chance of a meltdown in the United States within the next 20 years. (Published 11/ 17/87)

The Post's editorial "Nuclear Power and the Governors" {Nov. 7} overlooks the reason that the Shoreham and Seabrook nuclear plants have been sources of intense public controversy for more than a decade. The governors object because these nuclear plants are located in the midst of captive population centers, in places where no rational regulatory system would have allowed nuclear plants to be built.

In the early 1970s, as an assistant attorney general in Massachusetts, I represented that state in the initial hearings on whether Seabrook should be given a permit for construction. At that time, both Massachusetts and New Hampshire (through Warren Rudman, then its attorney general) as well as several citizens' groups argued against the site. It was plainly evident then, as it is now, that the 100,000 or more people who jam the nearby barrier beach during the summer would be trapped on the one narrow road out in the event of an accident.

At the time, the Nuclear Regulatory Commission ruled that an accident was so remotely improbable as to be "incredible" and that the beach-goers would therefore never have to be evacuated. A few years later, in 1979, the "incredible" Three Mile Island accident happened. Shortly thereafter, the NRC acknowledged that severe nuclear accidents can happen and passed a rule requiring, as a condition of operation, that each nuclear plant owner show that people within 10 miles of its site can be evacuated.

Seabrook was then still in the early stages of construction. Parties to the case petitioned the NRC to halt construction at least temporarily -- before $5 billion had been spent -- and hold hearings immediately to determine if the population around Seabrook could be evacuated in any reasonable time. At the urging of the owner, Public Service of New Hampshire, the NRC refused, stating that the company was proceeding with construction "at its own peril." The NRC's refusal was upheld by the U.S. Court of Appeals only because the agency promised that it would fairly review this issue after the plant was built and that the costs expended would be completely disregarded during that review. According to the NRC, if Seabrook couldn't meet the rules, it would not be allowed to operate, no matter how great the financial loss to its owner. It was not the plant's opponents who chose to make this case a game of economic chicken on a huge scale. On the contrary, the opponents anticipated what has taken place: that the federal government's promise would turn out to be a cynical fiction.

The fact is that the people around Seabrook cannot be evacuated rapidly or otherwise protected by sheltering. The Federal Emergency Management Agency held this past June that the emergency plans submitted by Gov. John Sununu for the New Hampshire part of the 10-mile zone do not meet its standards for public protection. Even if Massachusetts were to capitulate to the NRC's pressure today, that would not alter the basic demographic and geographic facts of the Seabrook site.

The NRC's own research shows a 10 percent to 15 percent chance of a meltdown in the United States within the next 20 years. That is precisely why the independent investigations after the TMI accident concluded that effective emergency response is as important an element in ensuring public safety as is reactor design. If Seabrook or Shoreham failed to meet the rules related to plant design, The Post would not be applauding the NRC for softening the rules. Weakening the emergency rules is as pernicious as relaxing design rules.

The governors have concluded that it is simply not possible to evacuate all those at risk in the event of a radiation release at Seabrook or Shoreham. On the basis of expert advice and studies, they also recognize that if a nuclear accident happens, it is the state that will be forced to cope with the consequent deaths, injuries and contamination.

-- Ellyn Weiss The writer is general counsel of the Union of Concerned Scientists.