Unplanned Nuclear Reaction Rare
By H. JOSEF HEBERT Associated Press Writer
10-01-99 0142EDT
WASHINGTON (AP) -- There has been only one case in more than three decades in
which an unplanned nuclear chain reaction occurred at an American nuclear fuel fabrication
plant, industry and government officials say. But it killed a worker. It is extremely rare
for nuclear fuel to reach unexpected ``criticality,'' as apparently occurred at a fuel
plant Thursday in Japan where three workers were exposed to high levels of radiation and
hundreds of people were evacuated before the reaction was controlled.
There are seven nuclear fuel fabrication plants in the United States.
The only incident involving a nuclear chain reaction at a fabrication plant was
35 years ago at a plant no longer in operation near Charleston, R.I., said Michael Weber
of the Nuclear Regulatory Commission.
The incident in 1964 occurred when a worker poured a bottle of uranium solution
into a container for which it was not suited and the material went critical as he leaned
over the vat, killing him, Weber said.
Eight years ago at a fabrication plant operated by General Electric in
Wilmington, N.C., workers struggled for several days to keep uranium in a vat of water to
avert a nuclear chain reaction. They finally succeeded in cooling down the uranium by
injecting oxygen.
``They took a (uranium) solution and introduced it into (what) ... was not a
suitable tank,'' said Weber, violating NRC rules for safeguarding the nuclear material.
``There are very strict controls that we put on the plants,'' said Weber. These
include specifications on how much uranium can be in a container, the shape of the
container and the mass within a container. If any of these requirements are violated,
criticality can occur, he explained.
The accident in Japan occurred at a fuel fabrication plant, similar to seven
such plants operated by private companies in the United States, although the fabrication
process in Japan is somewhat different, nuclear expert said.
While the Japan incident continues to be investigated, it is believed the
nuclear chain reaction occurred when workers placed more than six times the amount of
uranium allowed into a vat of nitric acid, said an industry source who spoke on condition
of not being further identified.
The acid normally is used to remove impurities from recycled uranium left over
from fabricated fuel pellets, although the exact purpose of the actions at the Japanese
plant were not immediately known.
``This is a serious nuclear accident,'' Energy Secretary Bill Richardson said in
a telephone interview from Russia, where he is visiting nuclear facilities. ``The good
news is that it is not a widely contaminated area. It's a limited area.''
Richardson said the United States and Russia were prepared to send a joint team
of nuclear experts to help Japan deal with the problem. As of late Thursday, no request
for such assistance had been received. Officials in Japan said radiation levels near the
plant were back to normal.
But the issue was sure to fuel further the attack on Japan's nuclear program,
which, unlike the U.S. program, includes reprocessing spent nuclear fuel and widely using
plutonium mixed-oxide fuel. There is no indication plutonium was involved in the radiation
incident, however.
``Clearly, the Japanese are stepping ahead of themselves. It should give them
pause,'' said Paul Leventhal, head of the Washington-based Nuclear Control Institute. The
group has been critical of Japan's fuel reprocessing, arguing it leads to increased
concerns about proliferation of nuclear materials including plutonium.
The United States banned nuclear fuel recycling in the 1970s because of concern
it would make it easier for nuclear materials -- especially weapons-suitable plutonium --
to fall into the wrong hands.
The uranium fuel cycle in the United States is spread across a number of
facilities. First, uranium ore is converted to hexafloride gas, then it is shipped to
another plant for enrichment, and then to one of seven fuel fabrication plants that turn
the gaseous or liquid uranium into powder and then reactor fuel pellets.
According to the NRC, the seven U.S. nuclear fuel fabrication plants are: an ABB
Combustion Engineering plant in Hematite, Mo.; a General Electric plant in Wilmington,
N.C.; a Westinghouse plant in Columbia, S.C.; a Nuclear Fuel Services plant in Erwin,
Tenn.; the Framatome Cogema Fuels plant in Lynchburg, Va.; the BWX Technolgies plant, also
in Lynchburg; and a Siemens Power Corp. plant in Richland, Wash.
(PROFILE (CO:General Electric Co; TS:GE; IG:CGL;) )
