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hazards are only significant for close proximity/prolonged
exposures.
(3) GAMMA RAYS. Are the most penetrating of the
radiations emitted by DU. The exposure rate at 1 inch
from a typical source is 7 mrem/hr, but drops to undetectable
levels at a distance of about one to two feet from
most DU counterweights.
f. CHEMICAL HAZARDS FROM DU. Ingestion or inhalation
of DU may pose a chemical toxicity hazard. Once
DU enters the lungs much of it is dissolved in the blood.
It is then dispersed throughout the body and concentrates
primarily in the kidneys, bones, and liver, remaining
there for years. The metabolism of DU by the
body can damage tissues. These chemical effects include
kidney damage, and can be more serious than
those caused by the radiation if the exposure is acute.
g. PHYSICAL HAZARDS FROM DU. DU can be an
internal exposure problem when inhaled or incorporated
into the body through ingestion or open wounds. The
degree of risk from inhaled DU is directly related to the
particle size and exposure duration. A burning piece of
DU can emitted highly respirable particles (1-10 um
AMAD), and thus a DU fire (exhibited by white smoke)
should always be considered an internal exposure hazard.
Ingestion or incorporation of DU into open wounds
can also be a hazard. However, due to the relatively insoluble
nature of DU, inhalation exposure is considered
the greater risk. Appropriate emergency response actions
should always be taken during and after a DU fire.
These actions include crash site entry upwind, use of
respiratory protection (SCBA or HEPA filtered mask) if
available, and radiation surveys and decontamination of
all personnel and equipment exposed to fires involving
DU. Treatment of life
PENETRATION DISTANCES
ALPHA
BETA
GAMMA & X-RAYS
NEUTRON
PENETRATING ABILITY OF 3 RADIATIONS
4
2a
0
-1By
++
1 n
PAPER PLASTIC LEAD CONCRETE
3-19
TO 00-105E-9
threatening injuries always takes precedence over radiation
surveys or decontamination. DU
exposure, whether external or internal, is always accompanied
by some health risk, however during most aircraft
accidents, the risk from other hazards (UXOs, jet fuel,
composite materials, and various organic compounds
emiited during a aircraft fire heavily outweighs the risk
from DU exposure. This is due primarily to the relatively
low specific activity of DU and its low solubility when exposed
to high temperatures (i.e. UO2 form).
h. HOW DO I PROTECT MYSELF FROM DU HAZARDS?
External doses from DU are easily controlled by standard
health physics practices of reducing time, increasing
the distance, and using shielding around counterweights.
Wearing gloves will prevent skin contact and
reduce beta exposure when handling DU. Protective respiratory
masks are needed if DU dust exists. Dust from
DU is common when the material undergoes oxidation
(the material turns from silvery-white to a black or brownish
color). When in this state, the dust should be suppressed
by atomized water spray. As an internal radiation
hazard, thermoluminescent dosimeters and other
monitoring devices do not provide any reduction in exposure.
i. HOW MUCH RADIATION AM I BEING EXPOSED
TO? We are exposed every day to radiation that occurs
naturally in the environment. This background radiation
comes from cosmic and terrestrial sources that exist in
food, water, and the air. On average, Americans receive
350 mrem per year from background radiation sources.
Through safe handling practices, radiation from DU will
be significantly less than these background sources. By
Federal law, dose limits to members of the general public
are 100 mrem per year. As well, the Air Force applies
this limit to non-radiation workers including most aircraft
maintenance personnel.
j. SAFE HANDLING INSTRUCTIONS FOR DU.
(1) No drilling, filing, machining, sanding, or other
abra-sive procedures are permitted.
(2) Where prolonged body contact is possible or
where abrasive operations are likely to affect the DU.
DU parts will be removed and stored in secure areas.
(3) Materials used in handling corroded or damaged
DU (such as gloves or plastic wrap) will be bagged in
plastic and placed in radioactive waste containers for disposal
IAW applicable technical orders.
(4) Personnel handling DU will wash hands thoroughly
with soap and water immediately after removal of
gloves, before eating, drinking, and smoking or at the
end of work shifts.
(5) The Radiation Safety Officer should survey areas
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