Scienza

rubrica  a cura di
Mario Bruschi
Dipartimento di Fisica
Universita` "La Sapienza"
e-mail: bruschi@roma1.infn.it

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Il sito di Greenpeace
contenente un calendario degli incidenti nucleari

……………………………………………….

September 16, 1999

Ohio uranium contamination reported

WASHINGTON (AP) - Federal reports collected by a watchdog

group indicate a southern Ohio defense plant handled a more

dangerous, undiluted type of plutonium-laced uranium than the

government has previously acknowledged. Documents gathered

by the organization Uranium Enrichment Project include an

Energy Department report describing plutonium contamination

at an unused building in the Portsmouth Gaseous Diffusion Plant

complex at Piketon, Ohio. Another described spent nuclear fuel

going directly from a federal facility in Idaho to the Portsmouth

Plant. Spent nuclear fuel would have a higher plutonium level

than material that arrived at Piketon from its sister facility in

Paducah, Ky., since some purification would have been done in

Kentucky.

………………………………

September 21, 1999

Uranium workers detail safety flaws

PADUCAH, Ky. (AP) - Workers at a federal uranium processing

plant wiped "green salt" off lunch tables, finding out later the

substance was actually a radioactive byproduct, current and

former employees testified at a hearing Monday. "Time after time,

we were put at risk, lied to and made to feel that we were safe,"

Phillip Foley, a 24-year worker at the Paducah Gaseous Diffusion

Plant, told a subcommittee of the Senate Committee on Energy

and Natural Resources. Foley testified during the first of several

planned congressional hearings into the operation of the plant.

For years, employees have complained about an increased

number of cancers they believe are linked to radiation exposure

while working with uranium they did not know was laced with

plutonium.

////////////////////////////////////////////

September 22, 1999

Buried radioactive site probed

DENVER (AP) - Back in 1991, the EPA thought the problem at the

old Shattuck Chemical Co. plant had been laid to rest. Instead of

digging up the contaminated soil and hauling it away, the EPA

decided to mix the more than 50,000 cubic yards of radioactive

dirt with concrete and fly ash and bury it on the spot under rock

and clay, creating a tomb designed to last hundreds of years. Now

that decision may come back to haunt the agency. City leaders

and residents of the blue-collar neighborhood surrounding the

Shattuck Superfund Site contend the waste is sinking and fear

that contamination may have already seeped into water supplies.

They are demanding the tomb be dug up and shipped out of state.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

  September 24, 1999

Paducah worries about radiation

PADUCAH, Ky. (AP) - The way the employees tell it, the

Paducah Gaseous Diffusion Plant sometimes operated as if Homer

Simpson were running the place. Except that what happened

there wasn't funny. Workers used to wipe "green salt" off the

plant lunch tables, fully aware it was a radioactive byproduct of

the plant's main task - enriching uranium for use as fuel in

nuclear reactors. They would bury truckloads of uranium

shavings that ignited and burned upon being exposed to the air.

They would dump thousands of barrels filled with radioactive

contaminants into ponds and bury them in the ground. All the

while, they were told they were working with materials that were

"safe enough to eat." Now the employees and many other people

in Paducah fear they are dying because of what happened at the

47-year-old plant, McCracken County's biggest source of jobs.

>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<

06:17 PM ET 09/27/99

Nuke Tank Explosion Said Unlikely

By LINDA ASHTON= Associated Press Writer= YAKIMA, Wash. (AP) _

Radioactive waste has risen like bread dough in a million-gallon storage tank at the Hanford nuclear reservation, provoking concerns about a possible explosion or environmental contamination. The managers at the Department of Energy site near Richland, less than 10 miles from the Columbia River in south-central Washington, say both scenarios are unlikely. ``The chance of explosion is very low,'' said Rick Raymond, the project manager for the contractor, Lockheed Martin Hanford. Still, ``any time you have a situation where you're trapping gas faster than releasing it, it's an unacceptable situation and needs to be dealt with in an urgent manner.'' The radioactive waste in Tank SY-101 is a byproduct of the process used to extract plutonium from uranium irradiated at Hanford's now-defunct nuclear reactors. The tank contains cesium and decaying organic materials that generate hydrogen, nitrogen, nitrous oxide and ammonia. The tank became notorious in the late 1980s and early '90s as Hanford's ``burping'' tank because it released thousands of cubic feet of gas every three months or so. If an ignition source had been present, the flammable gases could have exploded. A mixer pump installed in 1993 took care of the problem by allowing the continuous escape of small amounts of gas. But it also created a new problem no one expected _ without the periodic releases of huge amounts of gas, bubbles began to build up in the meringue-like crust floating in the liquid waste. The crust began to thicken and grow. It is now about 10 feet thick in a tank just over 38 feet tall. The top of the crust is 26 inches from the top of the tank, although it was 2 inches higher in May, when Hanford managers began releasing gas at the same rate it is produced. While the possibility exists that the waste could spill over and breach the tank, the |-inch-thick steel welds on the double-shell tank should prevent that from happening, Raymond said. Beginning in late October or early November, Lockheed Martin Hanford will begin pumping out Tank SY-101, diluting 300,000 gallons of the radioactive brew as it is transferred to another tank, and then diluting the 700,000 gallons still in SY-101 with water. That should be a permanent fix, said Craig Groendyke, manager for the SY-101 project for the Energy Department's Office of River Protection. Hanford was established in 1943 as part of the Manhattan Project to build the atomic bomb. Plutonium for nuclear weapons was produced at the site until 1986. The site has 54 million gallons of radioactive waste stored in 149 aging single-shell tanks, 67 of which have leaked. Newer tanks, such as SY-101, have two shells, and none have leaked.

………………

06:22 AM ET 09/28/99

Radioactive Waste Rising in Tank

 Radioactive Waste Rising in Tank
 By LINDA ASHTON= Associated Press Writer=YAKIMA, Wash. (AP) _ 

 A vast waste tank at the Hanford nuclear
 reservation that used to ``burp'' gas has a new problem: The
 radioactive goop inside has risen like bread dough.
 	   While the development within the million-gallon tank has
 provoked concerns about a possible explosion or contamination,
 managers at the Department of Energy site in south-central
 Washington say both scenarios are unlikely.
 	   ``The chance of explosion is very low,'' said Rick Raymond, the
 project manager for the contractor, Lockheed Martin Hanford. Still,
 ``any time you have a situation where you're trapping gas faster
 than releasing it, it's an unacceptable situation and needs to be
 dealt with in an urgent manner.''
 	   The radioactive waste in Tank SY-101 is a byproduct of the
 process used to extract plutonium from uranium irradiated at
 Hanford's now-defunct nuclear reactors. The tank, less than 10
 miles from the Columbia River near Richland, contains cesium and
 decaying organic materials that generate hydrogen, nitrogen,
 nitrous oxide and ammonia.
 	   The tank became notorious in the late 1980s and early '90s as
 Hanford's ``burping'' tank because it released thousands of cubic
 feet of gas every three months or so. If an ignition source had
 been present, the flammable gases could have exploded.
 	   A mixer pump installed in 1993 took care of the problem by
 allowing the continuous escape of small amounts of gas.
 	   But it also created a new problem no one expected _ without the
 periodic releases of huge amounts of gas, bubbles began to build up
 in the meringue-like crust floating in the liquid waste.
 	   The crust began to thicken and grow. It is now about 10 feet
 thick in a tank just over 38 feet tall. The top of the crust is 26
 inches from the top of the tank, although it was 2 inches higher in
 May, when Hanford managers began releasing gas at the same rate it
 is produced.
 	   While the possibility exists that the waste could spill over and
 breach the tank, the five-eighths-inch-thick steel welds on the
 double-shell tank should prevent that from happening, Raymond said.
 	   Beginning in late October or early November, Lockheed Martin
 Hanford will begin pumping out the tank, diluting 300,000 gallons
 of the radioactive brew as it is transferred to another tank, and
 then diluting the 700,000 gallons still in SY-101 with water.
 	   That should be a permanent fix, said Craig Groendyke, manager
 for the SY-101 project for the Energy Department's Office of River
 Protection.
 	   Hanford was established in 1943 as part of the Manhattan Project
 to build the atomic bomb. Plutonium for nuclear weapons was
 produced at the site until 1986.
 	   The site has 54 million gallons of radioactive waste stored in
 149 aging single-shell tanks, 67 of which have leaked. Newer tanks,
 such as SY-101, have two shells, and none has leaked.
 	   
 	   
 	

…………………………………………

September 30, 1999

Findings on DOE plants released

EVANSVILLE, Ind. (AP) - A federal official said Wednesday the

radioactive contaminant neptunium posed a greater threat to

workers than plutonium at three Energy Department plants

because there was so much more of it. "I've been focused very

much on the neptunium and it's a little dismaying to me all the

attention that's given to plutonium," said David Michaels, the

Department of Energy's assistant secretary for environment,

safety and health. Michaels made the comment during a

teleconference with reporters to announce preliminary findings

from a review of the handling of recycled uranium years ago at

the Energy Department's three gaseous diffusion plants in

Paducah, Ky., Oak Ridge, Tenn., and Piketon, Ohio.

……………………………………………………………………..

  October 01, 1999

U.S. nuclear safeguards have failed

WASHINGTON (AP) - Despite strict rules to guard against

unplanned nuclear chain reactions, U.S. nuclear fuel plants have

had at least two incidents in which those safeguards failed,

according to government and industry officials. Still, these

officials said, it is extremely rare for nuclear fuel to reach so-called

"criticality,'' as apparently occurred at the fuel plant in Japan in

which three workers were exposed to high levels of radiation and

hundreds of people were evacuated. The accident in Japan

occurred at a fuel fabrication plant, similar to seven such plants

operated by private companies in the U.S. Scientists at the

Lawrence Livermore National Laboratory were monitoring

atmospheric conditions to track the radioactive plume created

when radiation rushed from the plant. Unlike nuclear reactors,

fuel fabrication plants do not have protective containments.

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