Proposed nuclear waste treatment plant part of INEEL’s disposal
challenge
By GREG MOORE
Express Staff Writer
Early this fall, the public will have its last chance to comment
on a proposed nuclear and chemical waste treatment plant, including an incinerator, at the
Idaho National Engineering and Environmental Laboratory (INEEL) near Arco.
The Advanced Mixed Waste Treatment Project is designed to put 1.8
million cubic feet of temporarily stored nuclear waste into a form suitable for disposal
at the Waste Isolation Pilot Plant (WIPP) in New Mexico. The waste needs to be compacted
and repackaged, and some of it incinerated.
British Nuclear Fuels Ltd. (BNFL), contracted by the U.S. Department of
Energy to build the $300-million plant, would like to begin construction by November. But
before it can, it will need to obtain hazardous waste permits from the state of Idaho and
the U.S. Environmental Protection Agency. A 45-day public comment period will begin in
late September, with public hearings held in Boise, Idaho Falls and, possibly, Twin Falls.
Between 1970 and the mid-1980s, waste from federal facilities,
primarily from nuclear weapons production at the Rocky Flats Plant in Colorado, was
shipped to INEEL for temporary storage.
When the waste began to wear out its welcome with the state of Idaho,
the state obtained an agreement from the U.S. government that the waste would be taken out
of the state for permanent disposal by 2018, preferably by 2015.
The waste to be removed is by no means all the radioactive waste stored
at INEEL. The DOE is seeking a solution for how to deal with waste stored in underground
pits—a far more daunting challenge. That waste is feared to be leaking into the Snake
River aquifer.
Above ground waste is in drums and boxes covered with plywood and tarps
and several feet of dirt. Much of it is "transuranic" waste, which has an atomic
number higher than that of uranium. Transuranic waste at INEEL contains plutonium, a
dangerous carcinogen if inhaled or ingested.
Much of the waste is "mixed waste," containing chemicals as
well as radioactive material.
According to information supplied by BNFL, the waste needs to be
treated before shipping for four reasons:
· To put it into packages suitable for transport.
· To reduce the volume, which would reduce the number of
truckloads required to transport it; and to take up less space at WIPP. The compacted
waste would also be more physically stable. The DOE has requested a 65-percent volume
reduction.
· To remove hazardous chemicals which cannot be stored at WIPP.
· To concentrate low-level nuclear waste into higher-level,
transuranic waste. By federal law, the WIPP plant is authorized to accept only transuranic
waste.
Before the waste can be treated and repackaged, workers at INEEL will
need to retrieve it from the storage bunkers and find out what’s in each container,
using x-rays, measurements of radioactivity and laboratory analysis of chemical samples.
According to Cal Ozaki, BNFL’s deputy general manager for the
project, the DOE has detailed lists of the contents of most of the containers. However, he
said, such information is not available for waste shipped during the early 1970s, and the
contents of those containers is less certain.
Containers with only solid items—machine parts, rags, clothing,
etc.—will go directly to a monster crusher with 2,000 tons of force to squeeze the
55-gallon drums into 18-inch-high "pucks." Those containers are expected to make
up 34 percent of the waste to be treated.
The proposed plant will have two disassembly lines for containers with
liquids or gases—one to pull contents out of boxes and the other for drums. Each of
those would be inside a 10-by-50-foot cell. Workers would operate remote manipulators from
outside cells to cut open containers and sort contents.
Some of that material—expected to constitute 22 percent of the
total waste—contains organic chemicals and will require incineration. According to
information supplied by the DOE, there are no other good alternatives for treating mixed
waste.
"We can’t just throw it away untreated—landfills will
eventually leak and the waste would contaminate groundwater," the written material
says. "Permanent storage is not a treatment, much less a solution. Emerging
technologies hold out hope for destroying toxic compounds and may someday prove preferable
to incineration. But they are still in development and are not presently proven or
available."
Ozaki said much of the material to be incinerated was originally in the
form of sludge from oil out of electrical insulators, but has since been mixed with grout
to form blocks of cement. Those, he said, contain polychlorinated biphenyls, commonly
known as PCBs. PCBs have been blamed for cancer and other health problems and must by
disposed of only through incineration.
According to Ozaki, the incinerator will have two combustion chambers.
Waste will be fed through the 25-foot-long primary chamber, where organic compounds will
be vaporized and pass into the secondary combustion chamber, where they will be burned,
turning into carbon dioxide and water. The solid material, still radioactive, will fall
out of the bottom of the primary chamber as ash, which will be encapsulated in concrete
for shipping and disposal.
Ozaki said the vapors and airborne particulates will pass through a
10-stage air pollution control system, which will remove the particulates and inorganic
chemicals.
Under state air-quality regulations, the incinerator will need to
remove 99.99 percent of each of the hazardous substances involved, and 99.9999 percent of
the PCBs.
Ozaki said the emissions from the incinerator’s 90-foot-tall stack
will be composed of carbon dioxide and water. Asked how many other substances will be
emitted, he said, "Quite frankly, we don’t think any will, but we can’t say
zero—it depends how far out beyond the decimal point you do your math. But we know it
will meet the 99.9999-percent regulation by a large margin."
Ozaki said his firm’s air pollution permits will set emission
limits at each stage of the pollution-control process. If any of these are exceeded, he
said, the incinerator will automatically shut down.
