Friday, October 12, 1990 - Page updated at 12:00 AM

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Hanford Leak Said To Be Underestimated -- Energy Agency Admits Blunder In Its Report

The Department of Energy now says 800,000 gallons of cooling water could have leaked from a ruptured nuclear-storage tank, in sharp contrast to the 5,000 gallons previously acknowledged as escaping from the Hanford container.

Discharges from some of Hanford's 65 other leaking tanks also could have been inaccurately reported, the agency admits. For example, cooling water was sprayed into another leaking tank, but no estimate is available on exactly how much was added.

In a letter sent late Wednesday to the state, the federal agency calculates that 832,000 gallons of water was added to Tank 105A in eight years. After evaporation, the Energy Department estimates from 632,000 to 800,000 gallons leaked from the single-shell tank, helping to flush radioactive and chemical waste into the desert soil. It is the worst leak ever made public by Hanford officials, far surpassing a 1973 incident at another single-shell tank that spilled 115,000 gallons of radioactive waste.

The Energy Department, though, warns that records are spotty for much of the period from 1971 through 1979, and that the estimates for Tank 105A are rough calculations. ``A clear chronology of water additions to Tank 105A is not known at this time. The records reviewed show inconsistencies and in some cases missing data,'' wrote Ron Gerton, director of Hanford's waste-management divisions.

The Energy Department says it will provide more information by Jan. 10. Still unknown is exactly how much radioactive waste leaked from the million-gallon concrete tank, ripped open in a 1965 steam explosion. The Energy Department says the waste did reach the surrounding soil but not the ground water.

Until now, public documents on the tank, built in 1955, indicate that only 5,000 gallons of waste had been spilled. But the reports did not calculate the amount of cooling water added to Tank 105A to prevent either an explosion or a melting of the container from the hot waste.

Memos and other internal documents reveal that a million or more gallons of cooling water may have been added to Tank 105A, one of 149 single-walled tanks at the site on the Columbia River. The aging tanks, along with 28 newer double-shell tanks, hold the waste from 45 years of making plutonium.

The state, unhappy at not being told about the leak before now, requested detailed information about Tank 105A and additions of cooling water.

The Energy Department and Westinghouse Hanford Co., the main contractor at the site, sent a 21-page reply to the state Department of Ecology, but said more time is needed to provide a complete picture of what happened at that tank and others.

``The numbers are pretty incomplete,'' said Don Provost, a technical manager at the Department of Ecology's office of nuclear and mixed waste. ``There are some big holes in the information they gave us.''

Provost said yesterday the state was surprised that the Energy Department backed away from its earlier position that most of the cooling water had gone up as steam in Tank 105A. Instead, the calculation is that only 40,000 to 200,000 gallons evaporated - meaning that under the most optimistic estimates, three-fourths of the cooling water leaked.

Copyright (c) 1990 Seattle Times Company, All Rights Reserved.


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