CHAPTER 11
RADIOLOGICAL DEFENSE AND RECOVERY
Provide information for calculating the length of
Learning Objectives: Recall the different types of
time that contamination will exist in the area.
radioactivity, detection, indication, and computation
Determine the effectiveness of decontamination
(RADIAC) and dosimeter instruments and their design
measures.
limitations, the different types of radiological surveys,
and the different types of exposure control.
NOTE
Radiological defense is a very important part of
This chapter presents a brief introduction
the ship's recovery phase. Radiological defense is the
to specific radiac instruments you may use.
Detailed information on this subject is found
area of nuclear survivability that is most subject to
in the Naval Ships' Technical Manual (NSTM),
management by the ship. Even if the ship is physically
chapter 070.
unaffected, the overall mission capability will be
reduced by the effects of radiation on the crew. The
TYPES OF RADIAC INSTRUMENTS
radiological hazard can endanger ships in areas
hundreds of miles from surface zero and it lasts the
The detection of nuclear radiation is of vital
longest of any of the nuclear weapon effects. That is
importance to personnel. Serious injury or death can
why it is important to minimize the radiological
result from exposure to sufficient quantities of these
hazard to personnel through the proper use of
invisible rays and particles. In considering the effects
on personnel exposed to radiation, we need two kinds
radiological defense and recovery procedures.
of information:
RADIAC INSTRUMENTS USED FOR
1. The intensity of the radiation field
RADIOLOGICAL DEFENSE
2. The total dose or quantity of radiation received
per exposure or time interval
Learning Objective: Recall the different types of
"INTENSITY" may be defined as the strength of
RADIAC and dosimeter instruments and their design
the radiation. It is expressed as a quantity of radiation
limitations.
per unit of time. The quantity unit used is the roentgen
or the rad, and the time unit is usually the hour.
Nuclear radiation once present cannot be detected
Therefore, you need to remember the following:
b y a ny o f t h e five s e n s e s . T h e r e f o r e , s p e c i a l
INTENSITY is expressed as roentgens per hour
instruments and devices have been developed to do
(R/hr) or as rads per hour (rad/hr).
this job. From the military standpoint, we not only
need to detect radioactivity but we also need to know
DOSAGE is expressed in two values: the
where the radiation is and what the intensity is.
EXPOSURE DOSE, measured in roentgens, and
RADIAC instruments serve both of these needs and
the ABSORBED DOSE, measured in rads.
are designed to perform the following functions:
NOTE
Detect beta and gamma radiation.
A roentgen is a unit of radiation dosage
Measure the intensity of radiation.
equal to the quantity of ionizing radiation that
will produce one electrostatic unit of
Measure radiation dose.
electricity in one cubic centimeter of dry air at
0 Centigrade and standard atmospheric
Determine the extent of contamination.
pressure.
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