[This tape was transfered from a 16mm film original by Colorlab
for the National Library of Medicine, April 2006,
NLM call number HF 1245]
[Music]
[The U.S. Department of Health, Education, and Welfare, Public Health Service, Presents]
[Radioactive Waste Disposal]
[Produced by the Communicable Disease Center for National Institutes of Health, Plant Safety Branch]
[Narrator:] As the use of radioactive materials increases,
the problems associated with the disposal
of the waste become ever more important.
Of all known toxic materials,
radioactive nuclides alone cannot be detoxified
or rendered harmless by any known chemical or physical processing.
Safe disposal of these materials requires that they be so segregated
that any return to man is in such a low concentration
as to be certainly harmless.
All manner of possible return paths must be considered
in choosing a processing and disposal method.
Disposal by burial on land requires the utmost care
to ensure that there is a negligible contact between
the waste product and water sources
through which the isotopes might return to man,
either directly or through food chains.
When intermediate products such as edible plants, animals,
and fish are involved,
the effects of biological concentrations of particular nuclides
in these intermediates must be carefully appraised.
[Intermediate Waste]
The most common radioactive waste problems concern the relatively
small user of isotopes obtained primarily from nuclear reactors.
[High Level Waste]
The high level waste originating from reactor operation itself,
and the associated chemical processing,
require special handling at the installations where the wastes originate.
The National Institutes of Health is an organization
devoted to research in clinical medicine
and the associated basic sciences.
Some 500 members of the scientific staff use about 100 curies
of radioactive isotopes each year.
Because of the biological emphasis of the research program,
carbon-14 and hydrogen-3, or tritium,
are the most commonly used nuclides.
Waste disposal methods must take into account
the particular properties of these isotopes.
At the National Institutes of Health,
the Radiation Safety Office is the organization
responsible for all radiation safety operations.
These operations include the processing
and disposal of radioactive wastes.
Safety office functions center around the isotope laboratory,
located apart from other laboratories and service buildings.
The disposal methods to be shown are the result
of over ten years of development
in cooperation with the United States Coast Guard.
The deep sea was chosen as the most desirable ultimate depository.
Burial at sea must be carried out so there will be no interference
with either commercial or sport fishing.
No significant concentrations of any isotope deposited must appear
at the surface of the sea or on any beach.
The waste disposal area, approximately 90 miles due east of Norfolk,
is over 1,000 fathoms in depth.
[Waste Disposal Area, Atlantic Ocean, 90 Miles, Depth Over 1,000 Fathoms]
Radioactive waste processing and packaging is carried out
in a restricted area near the isotope laboratory.
This area is surrounded by a custodial fence to separate it
from the activities and traffic of the Institutes.
Radioactive wastes must be classified into several different types,
and the disposal governed accordingly.
Here a chemical experiment is originating wastes of varying levels of activity.
Samples are being pipetted out for measuring preparatory to initiating the proper disposal procedures.
These liquid wastes will be assorted
depending upon the level of activity
as measured with the portable survey meter.
Carefully measured samples are placed in the counting
planchets to obtain the standardized volume
for checking with the scintillation counter.
All of these manipulations take place inside a hood
with absorbing paper underneath materials
so that spills can be readily discarded.
The waste of low activity will be disposed of directly
into the regular sewer system,
with water flushing the sample down the drain at the disposal time.
This other waste, which was found to contain somewhat greater activity,
will be put into a special sewer system.
This leads to a large underground retention tank
where the waste will be held for an appreciable length of time
before being released to the municipal sewer system.
Both of these wastes are short half-life,
or else disposal by either of these means would not be allowable.
Waste containing carbon-14 or tritium cannot be classified
by the crude assay method previously shown.
With these weak beta emitters, carefully prepared samples are counted in a liquid scintillator.
The scintillating solution,
and the photo multiplier tubes picking up the tiny flashes of light,
are kept at a very low temperature
in a deep freeze to reduce the effect of extraneous disturbances
on the electric circuits.
Carbon-14 and tritium wastes that are too concentrated
for direct disposal will be kept for burial at sea.
Each of these nuclides have a half-life that is too long
for appreciable decay to occur during any practical storage period.
Patient treatment areas generate large quantities
of contaminated articles, with bed linens an outstanding example.
Wherever possible, patients receiving radioisotopes
handle their own urine collections in the treatment areas.
Urines containing gamma emitters are kept
in heavily shielded containers and are collected at frequent intervals.
Another source of active waste material
comes from animal experiments.
This animal has been injected
with a long-lived radioactive material.
Note that the experimenters are wearing rubber gloves
to avoid contamination of hands.
Blood samples are withdrawn,
placed into counting planchets
for drying and subsequent assay.
Marking tape is used
whenever radioactive material is involved.
It is most important that all packages be so marked,
and an approximate value given of the amount
of the isotope present, and the isotope identified.
Animal carcasses are stored at low temperature
until ready for disposal by approved methods.
Since licenses for radioactive materials are given
by possession limits,
it is necessary to keep a careful account of the isotopes that are thrown away.
Each package must be marked with the amount of the isotope which it contains.
Throughout all waste disposal operations and processing,
accurate records are kept of radiation exposure
of all personnel involved.
Film badge monitoring devices are loaded
and prepared for issue throughout the institutes.
A most important part of the monitoring consists of keeping records.
Most of these records will be needed perhaps
five to ten years after they have been entered,
so neatness, accuracy and legibility
are most important items in the record keeping.
Records must be kept of all radioactive waste materials
that are disposed of by whatever means.
This represents about one-half of a day's collection
from the laboratories and clinical areas at the Institutes.
Delivery of radioactive materials to the radiation safety office
is made so easy that there will be little or no temptation
to dispose of these materials by other methods.
Otherwise, these radioactive materials might be found in the regular trash containers,
or dumped indiscriminately into the municipal sewer system.
The polyethylene bags are the liners of the waste containers
which are handed out to all users of active materials.
Wastes are classified and records kept of each package,
its location, and the method of final disposal.
Here, materials of short half-life are being kept for decay
and for later incineration.
Materials which have too long a half-life to allow decay to take place
will be put into children-sized concrete burial vaults
for ultimate disposal at sea.
Liquids, solids, and activities of many different levels
are some of the diverse materials which are collected.
Vaults are standard commercially available containers of convenient size.
They are made of steel-reinforced concrete and have lifting eyes cast into the bottom.
Short lengths of steel cable are attached to these eyes for handling.
The vaults are packed as carefully as possible
to include a maximum amount of material.
This cuts down the number of containers required and aids
in obtaining the density required to ensure sinking in the ocean.
Special waste products require special methods of handling.
Here are the steps that lead to the ultimate disposal of some cobalt pellets.
They have already been packaged in lead and welded into a steel pipe.
Spacing rings encircle the cobalt container so that the pipe
will be centered into the steel disposal drum.
The drum will then be filled with concrete.
Although there is some gamma ray activity
at the surface of the steel container,
the handling is done without intervening shields because of the relatively short time involved.
Observe how the centering devices help as the pipe is lowered into the drum.
Note the marking of the drum to indicate that it now contains radioactive materials,
the amount and isotope being marked on the label.
A wet concrete mortar is now poured
around the steel container containing the cobalt pellets.
The concrete in this particular case fills the drum readily
without any tamping,
and a solid mass will result without any agitation.
The concrete can be mixed to any desired consistency.
The steel pipe is suspended from the top of the drum
to prevent it sinking through the soft mass before the concrete hardens.
An immediate check is made of the surface gamma activity of the container.
This is to make sure that it will comply
with all of the interstate commerce regulations
governing the shipment of radioactive materials over state highways.
The markings on the drums are made in accordance with requirements of AEC licensing.
They cover the amount and the isotope contained therein,
also identifying marks, so that if there is any future recovery,
the origin of the drum can be identified.
Waste materials are packed in the concrete burial vaults
and mixed intimately with a thin concrete mortar.
All of the polyethylene containers are broken
to ensure an intimate mix with the concrete
and also to obtain a maximum density
to ensure sinking in the ocean.
The vaults are shallow enough to permit
good mixing of the contents with thin concrete.
The safety office personnel working directly
over the vaults wear respirators to prevent the inhalation
of airborne radioactive materials.
This is not considered necessary for the cement workers
who have a casual contact and are not working directly over the vault
during the active breaking of the polyethylene containers.
The vaults are actively agitated
during the entire filling operation to eliminate voids
and obtain as intimate mixing as possible.
Actual tests show that the finished containers remain intact
under the hydrostatic pressures at depths of at least 6,000 feet.
Vacuum pumps used on a radon plant are contaminated
to an extent where decontamination would be more expensive than replacement,
so they are disposed of along with other types of waste.
This is a sample of the wastes collected at an institution
such as the National Institutes of Health.
The vaults are finally sealed with a few inches of richer cement mix
than is used in the body of the filling.
These vaults shown here represent about one day's processing
and contain approximately six months' waste supply from the Institutes.
Upon completion they are checked for gross gamma activity
with the gamma-sensitive meter.
Each vault must be marked with identifying symbols
to show the isotope contained therein, the approximate amount,
the authorization permits under which shipment is made,
and marks and dates for NIH identification purposes.
The radioactive materials contained in these vaults
are considered to be class D poisons.
And therefore require the use of
Interstate Commerce Commission labels,
as well as direct identification as radioactive materials.
The new concrete surfaces are painted to reduce moisture absorption
while awaiting final disposition.
The finished vaults are now checked to be sure there is no surface contamination.
This is done by making a series of wipes
across the surface of the finished concrete.
These wipes are then counted in a gas-flow counter.
This is required because of the possible presence
of either carbon-14 or tritium, both of which are beta emitters.
An automatic counter is used, each wipe being counted
for a preset number of counts,
with the time required being recorded on a paper tape.
If the counts are within prescribed limits, essentially zero,
the vaults can then be handled without gloves from here on.
If positive contamination is found on the surface,
it will be removed by scrubbing
or by covering the contaminant with a heavy coat of paint
or some other covering material.
Upon completion of the counts, the counting rate is carefully noted
and becomes a part of the record of each finished container.
As the vaults are made ready for loading into trucks
for transportation to the port of embarkation,
a final gamma check is made on each individual vault
to be sure that it fulfills the requirements for transportation over public roads.
Each truck is loaded so that very low activity vaults,
or those containing only nonpenetrating beta emitters,
are placed next to the driver.
This provides additional shielding between him and any vaults
which show an appreciable gamma activity at the surface.
This precaution is perhaps unnecessary but is carried out simply
because any radioactive exposure should be avoided whenever possible.
Each convoy is accompanied by a trained monitor in a separate vehicle
carrying monitoring instruments capable of making measurements
at any radioactive emergency which may arise during the shipment.
A truck convoy leaving for the port of embarkation
must comply with a variety of regulations.
Weight and vehicle spacings while underway are prescribed by state law.
The trucks, pulling into an official state weighing station,
have red lights flashing, merely to indicate a turn off the main highway.
The lights are not a part of the procedures associated
with the shipment of the radioactive materials.
Truck loadings are made with due regard for the loads allowed by state regulations.
Each finished vault weighs about 1,500 pounds in air.
Each shipment will have a total weight of 20 to 30 tons.
After weights are checked the convoy proceeds,
at all times following the regulations required for convoys.
Proper spacing between vehicles is maintained
so that overtaking vehicles need not pass the convoy as a unit,
but can pull in between the trucks if necessary.
In general, the convoying sedan follows behind the last truck
to take care of any stragglers who may have mechanical difficulties.
The convoy ends at the Coast Guard base at Norfolk, Virginia
where the waste containers are loaded
onto the fantail of the Coast Guard cutter.
This vessel is equipped with steel trays which prevent
contact of the waste container with the wooden deck,
and in addition raise the shipment to a level
that will clear the rail of the ship
during the dumping procedure.
One of the larger trays shown here
is equipped with sections of roller conveyors to facilitate
the off-loading of the concrete vaults
at the designated dumping site.
The steel platform is for handling the steel drums.
Each set of concrete vaults is locked in position
by a special locking device which can be tripped at sea
for the safe release of the containers.
As in the case of loading the trucks,
preference is given to those vaults
showing some gamma activity at the surface
by placing them outboard and away from the positions
which will be occupied by the crew
during the normal working of the vessel.
It will be noted that here the crew members
are handling the vaults without protective gloves,
because of the previous checks which have shown the surfaces
to be completely free of radioactive contamination.
Before the trucks are released to return to the Institutes,
a final check is made with a thin window counter to be sure
that no contamination has been left in the truck bodies.
When this has been so demonstrated, the signs are removed,
and the trucks are available for regular duties without restrictions.
Aboard ship, steel drums are lashed down to prevent movement
during the voyage out to the dumping ground.
The hands and feet of the crew members are checked
to be sure that no contamination has been received
by any of them in loading the vaults and drums.
These surveys are conducted with a Geiger counter
which will respond to carbon-14 and more energetic emitters,
but which will not detect tritium.
With a thorough mixing of the wastes,
it is hard to imagine a contamination of tritium alone.
And so an absence of activity is assumed to indicate an absence of tritium also.
Tripping a dog releases four vaults
which go overside almost simultaneously
but without any damaging collisions.
This is done at the dumping ground
prescribed in the waste disposal license
granted by the Atomic Energy Commission.
Experiments conducted at depths of 1,000 fathoms or 6,000 feet
suggest that about 15 to 20 minutes is required
for containers to reach the bottom.
All materials are disposed of at a depth of not less than 1,000 fathoms,
which in the Norfolk area means approximately 80 to 90 miles due east,
to carry the ship beyond the continental shelf.
[80 miles, 90 miles, 1000 fathoms]
Here the fathometer reading for one particular trip indicates
that disposal is made at a depth of 1,000 fathoms.
[Music]
[Directed by...Wilmer H. Kimberly, Technical Advisor...Dr. Howard L. Andrews]
[The End, CDC M-443]