Reply #45: Reports of blue flash studied.. [View All]

Look how long it took for this to leak out:

http://nucnews.net/nucnews/2001nn/0106nn/010610nn.htm#084



Scientists offer varying theories about what may have caused event.

By Dennis J. Carroll
The Hawk Eye (Burlington, Iowa)
June 10, 2001
http://www.thehawkeye.com/specials/IAAP/breaking/b61000.html

Federal and state regulators are investigating the possibility that a runaway nuclear chain reaction at the Middletown munitions plant in the early 1970s released a large burst of radiation that may have killed two workers and sent large amounts of radiation into the environment.

One regulator, Dan McGhee of the Radiological Bureau of the Iowa Department of Public Health, said there appears to be "a 50-50 chance" that a nuclear "criticality" occurred in which people were killed.

According to Department of Energy reports, a criticality accident occurs when the minimal amount of fissionable material necessary to sustain a nuclear reaction inadvertently comes together, setting off the chain reaction.

There is a sudden release of energy and deadly radiation, but not necessarily an explosion.

Such an event is accompanied by a blue flash of light or a glow that can linger for some time.

It is thought that if such an event did occur at the Iowa Army Ammunition Plant, it may have occurred in one of the areas used to assemble and disassemble nuclear bombs.

In the entire Atomic Age, there have been only 60 documented criticality events reported worldwide, according to scientists at the Los Alamos National Laboratory in New Mexico, and only 21 fatalities reported since 1945.

Such an occurrence at the Middletown plant is not listed among those events, as published in a 2000 update of "A Review of Criticality Accidents" by the Los Alamos lab and Russian nuclear experts.

Investigators, who include the Iowa Department of Public Health, the Environmental Protection Agency and the U.S. Army Corps of Engineers, have centered their probe around information contained in recently declassified documents and the accounts of former IAAP workers who said they witnessed or were familiar with the event.

Pinning down a date has been difficult, but the reported flash is believed to have occurred in the summer of 1972 or 1973, according to researchers at the University of Iowa College Public Health who have talked with former nuclear weapons workers who said they saw or knew of the flash.

A report from the university survey team includes the account of a worker who said he witnessed a blue flash in a nuclear assembly room, then helped two injured workers who later died.

However, former workers remain reluctant to say much more --Êassuming they know more --Êand the reported victims have not been identified.

One is said to have died the day after the flash, the other a year later.

Nuclear weapons were assembled and, in later years, disassembled at Middletown in circular reinforced-concrete rooms, about 30 feet wide. The rooms were surrounded by earth and topped with tons of gravel to contain radiation from possible nuclear explosions or other radiation releases.

Daniel Bullen, former director of the nuclear reactor program at Iowa State University, said it is unlikely that a criticality would have occurred during the assembly or disassembly of a nuclear weapon.

"I would be extremely skeptical," he said.

Bullen is not involved in the IAAP investigation.

Other nuclear scientists have said such a glow could have been caused by a chemical fluorescence or phosphorescence or a glow from tritium -- a radioactive material sometimes handled by IAAP nuclear workers.

Scott Marquess, project manager for the EPA Superfund cleanup at the Iowa Army Ammunition Plant, said his agency is trying to determine whether there are residual signs of such a criticality that would remain nearly 30 years later.

For example, it is considered possible that fission materials from a criticality still might be embedded in nearby glass, and there still could be lingering radiation.

Bill Field, radiation expert with the university's team surveying the health of former IAAP nuclear workers, said the blue flash or glow seen by workers could have been what is known as Cerenkov radiation, in which charged radioactive particles traveling faster than the speed of light from a fission reaction release a blue glow.

That often is observed at nuclear power plants when spent nuclear rods are submerged in water, but that is a controlled environment.

In an April letter to Army officials urging a aerial radiological survey of the plant, Gov. Tom Vilsack cited recently declassified documents that he said refer to plutonium, "ground zero" and "an incident that may have led to contamination" in the early 1970s.

It has not be determined whether that "incident" was the blue flash seen by workers.

The Atomic Energy Commission assembled, test-fired and in later years, disassembled nuclear weapons and their components at IAAP from the late 1940s to the mid 1970s.