Work place monitoring haydar

1. Radiation Monitoring: Work
Place, Area and Environment
Monitoring
Training Course on Radiation Protection for Radiation Workers
and RCOs of BAEC, Medical Facilities & Industries, TI, AERE,
OCT 2021
Presented By:
Md. Abu Haydar
Principal Scientific Officer
Health Physics and Radioactive Waste Management
Unit, INST, AERE, Savar, Dhaka.

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Contents
 Introduction
 Work Place Monitoring
 Individual Monitoring
 Area Monitoring
 Environment monitoring

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Introduction
 Radiation monitoring involves the measurement of
radiation dose rate in the vicinity of a radiation
source, measurement of surface contamination, and
measurement of airborne radioactivity.
 According to the Bangladesh Atomic Energy
Regulatory Act, 2012 (Act No. 19 of 2012) and
Regulations 1997 (NSRC Regulations 1997) of
Bangladesh as well as other international bodies
(IAEA, ICRP etc.), the licensee of a
nuclear/radiological facility or practices involving
radiation sources must ensure the safety of the
occupational workers, public and the environment.
 To ensure the radiation safety of the occupational
workers, public and the environment, the radiation
monitoring program is essential.
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Introduction
Types of Radiation monitoring:
• Work Place Monitoring
• Individual Monitoring
• Environmental Monitoring
Radiation monitoring at different radiological
facilities Environmental
monitoring map for
RNPP
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Health: Public and private hospitals, Nuclear medicine
centers, Radioisotope production facility, X-rays
etc.
Industry: Industrial radiography/NDT, Nucleon gauge, Gas
mantle, Oil and gas explorations, Commercial
irradiator etc.
Research & Education: Operation and maintenance of 3
MW TRIGA MARK II Research Reactor (RR),
Food irradiation, Plant breeding, Insect
extermination, Accelerators etc.
NPP: Operation and maintenance of Rooppur Nuclear
Power Plant
NORMs: Coal mining, Beach Sand Minerals, Water
Nuclear/Radiological Facilities and Practices Involving
Radiation Exposure in Bangladesh
Introduction 3/5

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Introduction 4/5

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Type of facilities Radionuclides
Nuclear/Research Reactor
3H, 51Cr, 54Mn, 59Fe, 58Co, 60Co, 89Sr, 90Sr,
131I,134Cs, 137Cs, etc. Radioactive rare gas
Central Radioactive waste
Processing and Storage
facilities
3H, 14C, 60Co, 90Sr, 94Nb, 99Tc, 129I,
137Cs, etc.
Radioisotope Production
Facility
131I, 99mTc
Radionuclides Involved in the Nuclear/
Radiological Facilities
Introduction 5/5

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Work Place Monitoring

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Work Place Monitoring
What is Work Place Monitoring?
Workplace monitoring is an important technique to
achieve and maintain an acceptable protection of the
working environment from radiation hazards.
The objectives of the workplace monitoring:
 Confirmation of good or Identification of poor working
practices;
 Provision of information and/or Identification of changes
in conditions in the workplace;
 Identification of unusually high doses;
 Estimation of the exposure of workers;
 Provision of confidence in safety procedures and
improve workers attitudes to reduce their exposure;
 Provide information for the evaluation of doses in the
event of accidental exposures.
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Work Place Monitoring
Work Place Monitoring may includes:
• Dose rate measurement
• Surface contamination measurement
• Airborne contamination measurement
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Work Place Monitoring
• A sufficient quantity of suitable dose rate meters capable of
providing direct readings of the ambient dose equivalent
rate (H*(10)/h) with ranges from the μSv/h to Sv/h should
be available.
• Where high levels of surface contamination with beta/alpha
emitters is foreseen, equipment calibrated in H’(0.07)/h
should also be available.
• The equipment should be type tested and appropriate for
work in field conditions – for example some detectors with
liquid crystal screens are hard to read in broad daylight.
The screen should have back lighting for night work.
• The energy range, battery life and availability, temperature
range and other considerations are important criteria.
Requirement for Dose rate measurement
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It is important that:
1) Before making the reading, the worker should assure that
he or she is in a safe position or situation. When entering
a high dose rate area keep the meter turned on and
check the alarm settings earlier.
2) The worker using the dose rate meters should be familiar
with the equipment through use during routine work.
3) The dose rate meter passes through a functional test
every day before use: battery, cables, background and if
possible a check source.
4) In high dose rate areas, do not take the measurement too
quickly, take the minimum time necessary to make a
correct reading.
5) The detector can be wrapped in plastic to avoid
contamination.
Work Place Monitoring
Dose rate measurement
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Work Place Monitoring
Dose rate meters provide direct
measurements of external
exposure.
Dose rate measurement
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Work Place Monitoring
Dose rate measurement
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SL.
No.
Locations
Area
Classification
Bkg. Radiation level (Sv/h)
(Shutdown Condition)
Max. Gamma Dose-Rate (Sv/h)
at Power Level of
2.4 MW
Entrance Door (Ground floor)
Free Area
0.11 0.32
Neutron spectrometry laboratory 0.12 0.45
Control room (Operator position) 0.12 0.24
At the stack point 0.07 0.25
Staff seating room 0.13 0.50
Store room 0.11 0.22
Decay tank room 0.22 -
Public gallery (Glass wall)
Supervised Area
0.14 0.78
Control room (Glass wall surface) 0.16 2.46
UPS & computer room 0.15 2.10
Thermal column 0.08 2.88
Radial beam port-I 0.15 1.87
Radial beam port-II (on shielding surface) 0.12 2.06
Shielding surface of the Ion-exchange resin column 0.18 1.48
Charcoal Filter (C.F.) Inlet (before filtering) 0.11 2.38
C.F. Outlet (after filtering) 0.10 0.81
Entrance door (3rd floor) 0.13 0.61
Rabbit room 0.13 0.84
Tangential beam port 0.26 3.28
Outside the decay tank wall surface 0.28 3.56
Grating surface of the reactor top
Controlled Area
0.12 34.07
Primary cooling valve (MOV-1) 0.19 10.00
Piercing beam port 0.21 28.63
Surface of the Ion-exchange resin column 65.00 85.09
Primary pump 0.14 12.72
Heat exchanger’s surface 0.16 18.33
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In what circumstances the airborne contamination
measurement are needed:
 when gaseous or volatile materials are handled in
quantity
 during the processing of moderately (131I, 137Cs &
99mTc) to highly (239Pu, 241Am, 226Ra, 90Sr) toxic
radioactive materials
 during the handling of unsealed therapeutic
radionuclides in hospitals
Work Place Monitoring
Airborne contamination measurement
The monitoring of airborne
radioactive materials is
important because inhalation is
usually the most important
route of intake of such material
by radiation workers.
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Monitoring of airborne radioactive material in the
workplace can be used:
• to estimate worker intakes due to inhalation;
• to determine what protective equipment and
measures are appropriate;
• to indicate significantly elevated levels of airborne
radioactive materials;
• for assessing the individual dose when individual
in-vivo and/or bioassay methods are not available.
Work Place Monitoring
Airborne contamination measurement
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High Volume Air Sampler
HPGe Detector System
Airborne contamination measurement
Work Place Monitoring 10/15

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Whole Body Counting by FASTSCAN 2250
 Internal dose assessment to the occupational radiation
workers due to intake of radionuclides by Whole Body
Counting system.
Airborne contamination measurement
Work Place Monitoring 11/15

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Contamination is defined as the presence of radioactivity in an
unwanted area. Radioactive contamination occurs when
radioactive material is deposited on or in a working area,
object or a person.
The Dangers from Contamination
Contaminated areas in a lab can lead to;
external radiation exposure to lab personnel
internal absorption if comes into contact with skin or is
inhaled
interference with experiments being conducted in the lab
Work Place Monitoring: Surface Contamination
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Work Place Monitoring: Surface Contamination
Contamination Area
If removable radioactive contamination exceeds:
• 1,000 dpm/100 cm2 beta-gamma contamination or
• 20 dpm/100 cm2 alpha emitting contamination
High Contamination Area
If removable contamination exceeds 100 times the
Contamination Area levels:
• 100,000 dpm/100 cm2 beta-gamma contamination or
• 2,000 dpm/100 cm2 alpha emitting contamination
Detection of Contamination
To determine if an area has contamination, compare the
background counts/minute to the counts/minute of the wipe
or survey meter. If the ratio of counts/minute exceeds 3:1 the
area contains significant contamination.
The unit of contamination is dpm/100cm2, dms/cm2 or
Bq/cm2.
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 The probe should be held over contaminated area for at least 30
seconds so that it has sufficient time to respond to count rates.
 The probe should be held as close as practical to the surface being
monitored. It is important to avoid contaminating the probe.
 If the monitor does not have an energy discrimination device, alpha
particles may be distinguished from beta particles by placing a thin
sheet of paper over the sensitive area of the probe and beta
particles may be distinguished from photons by placing a thin metal
sheet between the detector and the contaminated surface.
 Monitors should be checked in a low background area before use.
Work Place Monitoring: Surface Contamination
Measurement of
Contamination
Contamination Monitor
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In some instances for spill (fixed or loose contamination),
where unsuitable geometry or interference from other
radiations prevents direct measurement, indirect methods of
surface contamination monitoring by a wipe or smear sample
from the surface using a tissue or filter paper may be used.
The smear should be taken to a lower radiation area or to a
sensitive radiation detector (HPGe) to be analyzed.
Monitoring techniques
Work Place Monitoring: Surface Contamination
Fig. (a) Smear Paper,
(b) Sample Collection
(c) Measuring Equipment
(a)
(b)
(c)
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Individual Monitoring

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Individual monitoring is the measurement of radiation doses
received by individuals working with radiation. Individuals
who regularly work in controlled areas or those who work full
time in supervised areas should wear personal dosimeters to
have their doses monitored on a regular basis.
Radiation Monitoring
Individual Monitoring
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An individual dosimeter is used for measurement of an
external dose:
Passive dosimeter
A passive dosimeter measures an accumulated dose. Since
the battery is unnecessary, the passive dosimeter is smaller
and lighter, and it can run out of power. However, it does not
have a direct readout and cannot measure a change of dose
rate, or have preset alarms to provide a warning of a change
of working conditions. Typical passive dosimeter are TLD,
OSL, RPL, Film etc.
Active dosimeter
An active dosimeter is an personal dosimeter (PD) which
integrates the counts of radiation and measures dose rate
and the accumulated dose. Since the active dosimeter needs
the power of a battery it generally is not suitable for
continuous use over several days, and it may not be useable
Radiation Monitoring: Individual Monitoring 2/3

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Personal dosimeters: TLD badges (A, B, C)
and film badges (D, E)
TLD
PD
Radiation Monitoring: Individual Monitoring 3/3

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Area Monitoring

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Area monitoring is the measurement of radiation dose
level at several pre-defined locations in and around a
facility where the radiation-emitting equipment is
located, or where radioactive sources are stored,
handled or used.
 To perform a routine evaluation of the radiation dose
to assure the safety of the working conditions for the
workers within the facility and
 To ensure the “Safety & Protection” of the
environment as well as the general public according
to ICRP/IAEA and national regulations.
Objectives
Area Monitoring
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Radiation Monitoring Points Located at 100 m
distance from BAEC TRIGA Research Reactor
Area Monitoring: Technique 2/3

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Area Monitoring: Equipment
Gamma Area Monitor
Noble Gas Area
Monitor
Neutron Area Monitor
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Environmental Monitoring

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Exposure Pathways of Human from
Radiation
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 Routine monitoring
 Emergency monitoring
 Fallout monitoring for nuclear tests or
accidents
Environmental Monitoring: Types
The main components of routine monitoring program
are:
 monitoring locations;
 environmental media and specific nuclides to be
monitored;
 monitoring frequency;
 analytical frequency;
 minimum detectable limit for specific radioactivity;
 individual dose assessment for population
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Environmental Monitoring
Routine Monitoring: Locations for
RR/RNPP
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Sampling Items Sampling
Points
Frequency Measurement
Technique
Environmental Radioactivity
Monitoring (ERM) around 10 km
radial distance of RR:
(i) Meat, Milk and Grass
(ii) Air
(iii) Others (Vegetables, Soil,
Surface Water, etc.)
08 Yearly Gamma
Spectrometry
Expected Radionuclides:
• Fission products : Cs-134, Cs-137, Co-60, Sr-90 etc.
• Natural : U-238, 235 & Th-232 decay series nuclide &
K-40
Environmental Monitoring
HPGe Detector for
Characterizing
Environmental
samples
Routine Monitoring: Data for RR
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Sampling Items Samplin
g Points
Frequency Measurement
Technique
Environmental Radioactivity Monitoring
(ERM) around 32 km radial distance of
RNPP:
(i) Soil-Vegetation
(ii) Local Food Stuff
(iii)Air Sampling
(iv)Drinking Water
(v)Surface Water-Surface Layer
(vi)Bottom Sediment-Aquatic Vegetation
~109 3 times in a
year
Gamma
Spectrometry,
Gross A-B, Alpha
Spectrometry,
etc.
Expected Radionuclides:
• Fission products : Cs-134, Cs-137, Co-60, Sr-90 etc.
• Natural : U-238, 235 & Th-232 decay series nuclide &
K-40
Environmental Monitoring
Routine Monitoring (Pre-operational): Data for RNPP
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 To obtain rapid information about the magnitude and
location of the immediate hazard so as to define the
type and extent of any necessary emergency procedures
and countermeasures.
 To assess the effective dose actually experienced by the
public taking into account any countermeasures have
been applied.
 To obtain scientific information on the results of the
emergency and on the behavior of the released
radioactive materials.
Objectives
Environmental Monitoring: Emergency
The emergency monitoring program is conducted
during any accident or incident in a nuclear/
radiological facility.
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Environmental Monitoring: Emergency
Stage Purpose Monitoring items
1st • Grasp the air concentration
• Dose rate
• Estimation of the public dose
• Decision making for countermeasures
(Sheltering, evacuation, stable iodine)
• Meteorological data
• Release rate of radioactivity from facility
• Gamma ray air absorbed dose
• Concentration of iodine, U, Pu in air,
leafy vegetable, drinking water, milk etc.
2nd • Precise monitoring in wide area
• Dose assessment of public
• Restriction of food intake
• Grasp on the impact of accident to
environment
• meteorological data
• Gamma air absorbed dose
• Concentration of radioactivity in air, leafy
vegetable, drinking water, milk, etc.
• Measurement of accumulated γ dose
Recover • Dissolution of the restriction
• Precise assessment of effective dose
• Every monitoring items routinely
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Environmental Monitoring: Emergency
Mobile Radiation Monitoring
Aerial Radiation
Monitoring System
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Nuclear weapons tests are experiments carried out to
determine the effectiveness, yield and explosive
capability of nuclear weapons. Throughout the 20th
century, most nations that have developed nuclear
weapons have tested them. Moreover, there are some
nuclear power plant accidents happened in some
countries.
Fallout monitoring for nuclear tests and accidents
Environmental Monitoring: Fall-Out
15 kiloton ground burst
of a nuclear weapon
Chernobyl nuclear power
plant accident in USSR
Fukushima Daiichi
nuclear disaster
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What is radioactive fallout?
Radioactive fallout is the particulate matter (dust) produced by
a nuclear explosion and carried high up into the air by the
mushroom cloud. It drifts on the wind and most of it settles
back to earth downwind of the explosion.
Environmental Monitoring: Fall-Out
Fall-out Sampling
Sampling frequency
12 times per year (every month)
Sampling point
Open place and avoid place which are directly influenced building or
trees
The height of the upper peripheral of the basin should be about 1 m
above ground.
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 Sampling tools
Large stainless steel
basin
Receiving area : 5,000
cm2
Diameter : 80 cm
Depth : 30 cm
Environmental Monitoring: Fall-Out
Sampling method
 Pour the pure water into the basin with 1 cm depth at the first day of
month and keep the same water level for whole month.
 On the first day of the next month, let the total sample flow into the
collecting container. Rub off and collect the attached dust on the
inner surface with a tool such as a rubber spatula.
 Rinse inner surface of the basin with water. Add the rinse water into
the collecting container.
 Measure the total volume or weight of the collecting sample.
Gamma ray spectrometry system is used to measure the sample.
Sampling
Instrument
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Thanks for your kind
attention!