The Crabshell
http://learning.blogs.nytimes.com/on-this-day/March-28/?th=&emc=tha213&nl=todaysheadlines
Radiation Is Released in Accident at Nuclear Plant in Pennsylvania
By Donald Janson
Special to The New York Times
By last night, officials of the Nuclear Regulatory Commission had still not determined the full extent of the radiation danger, but they said the amount of radiation that escaped was no threat to people in the area. Major amounts were released into the building housing the reactor, but workers were not believed to have been endangered.
Still, the accident at the Three Mile Island Nuclear Power Plant, on an island in the Susquehanna River about 11 miles south of Harrisburg, was described as the worst ever at an American nuclear generating plant.
The precise cause of the accident was not determined. A Federal nuclear expert suggested last night that it stemmed from problems with filters in the plant.
Officials of the Nuclear Regulatory Commission said radiation outside the plant was far less than that produced by diagnostic X-rays.
Come of the 60 employees on duty were contaminated, a plant spokesman said, but they did not require hospitalization. And the 15,000 people living within a mile of the plant were not evacuated, although a 'general emergency' was declared.
The commission said that "low levels of radiation" had been measured up to a mile from the plant and that traces had been found in the air up to 16 miles away. The amount in the immediate area were described as above normal for the plant site but below what is considered dangerous to health.
Details Remain Unclear
William Dornsife, a nuclear engineer with the State Bureau of Radiation Protection, confirmed that the radiation was not expected to pose a serious health threat, but there was some concern that radioactive iodine, one of the isotopes detected by the monitors, could show up in cow's milk in a week or two.
Details of the accident were in dispute almost immediately. Commission spokesmen first said it appeared to involve not just radioactive steam from the cooling system, but "direct radiation coming from radioactive material within the reactor containment." Last night, however, one commission investigator said the radiation was being emitted from nuclear-charged water.
Jack G. Herbein, a vice president of the Metropolitan Edison Company of Reading, one of a number of utilities that operate the power plant, said the accident began with the failure of a valve in a pump in the cooling system.
But officials of the company that manufactured the pump, Bingham-Willamette Company of
And late last night an engineer with N.R.C. suggested that malfunctioning "polishers," which he said were "filters," were at fault, not a pipe or valve. He did say, however, that that was still "supposition."
Whatever the initial cause, a cutoff of the flow of water in the primary cooling system appears to have resulted in uranium pellets in the fuel rods melting or cracking, releasing radiation before control rods could be inserted to stop the nuclear reaction.
In
The plant's backup system worked perfectly, Mr. Herbein said, but the overheating caused a rupture in a drain tank releasing radioactive steam. Because of the dangerous pressure buildup plant officials released some of the steam through the ventilation system.
Lieut. Gov. William Scranton 3d said the release of steam relieved "potentially dangerous pressure in the reactor chamber" but, because of a leak in the primary cooling system, "radioactive material was discharged into the air along with the steam." And late last night Federal officials said steam was still being vented to relieve the pressure.
Mr. Scranton also said the Department of Environmental Resources was not notified until after the discharges were halted at 1
When Mr. Herbein was asked about the delay in reporting the accident to the state and Federal authorities, he said that no escaping radioactivity was detected at first.
Part of the confusion over the exact chain of events was due to the inability of the monitoring team to inspect the reactor because of the high levels of radiation within the reactor dome. Based on readings taken outside, some N.R.C. officials said that levels inside the buildings were between 5,000 and 6,000 roentgens -- more than 10 times the lethal level.
However, company officials said those figures were too high.
Radiation Estimates Increased
Estimates of the amount of radiation escaping from the building were increased during the day, at one time reaching seven millirems. The rem is a standard radiation measurement that relates the strength of radiation (in roentgens) to the duration of exposure.
In a 5 P.M. statement, however, the commission said its maximum confirmed measurement, at a site a third of a mile from the plant, was three millirems, or thousandths of a rem.
The exposure from a standard diagnostic X-ray has been put at 72 millirems.
Scientists have held that exposure to manmade radiation should not exceed 170 millirems annually. At a news conference this afternoon Mr. Herbein reported a level of seven millirems at the plant, which would mean exposure to 168 millirems in 24 hours.
As company, state and Federal officials converged on the site, there were expressions of concern about the long-range effects of the radiation release.
Lieutenant Governor Scranton, who monitors energy matters for the state of
He said radioactivity had been detected in small amounts in
There was no radiation found in the river, Mr. Herbein said.
Company officials took pains to reassure the public.
"This is not a 'China Syndrome' type situation," said
The nuclear generator, which was operating at its full capacity of 959 megawatts, is one of two at the site and was put in operation only on Dec. 30. The other, which had been shut down for refueling, was installed in 1974.
Front Page Image Provided by UMI
© 2011 The New York Times Company
Donations can be sent to the
"The master class has always declared the wars; the subject class has always fought the battles. The master class has had all to gain and nothing to lose, while the subject class has had nothing to gain and everything to lose--especially their lives." Eugene Victor Debs
No comments:
Post a Comment