An important activity to be held in radiation protection is the location of radioactive sources. The present work was devoted to the development of a virtual dosimetry tool for locating and detecting such sources. To this end, was created a three-dimensional virtual model of the Instituto de Engenharia Nuclear – IEN, endowed with virtual characters (avatars), capable of move and interact with the environment, radiation detectors (fixed and mobile) and radioactive sources. Aiming to assist in planning physical security of nuclear installations, the tool developed allows the detection simulation of individuals carrying radioactive sources through detectors installed at strategic points of the site. In addition, it is possible to detect and locate sources by handling portable detectors, operated by characters within the virtual environment. The results obtained show the behavior of the radiation detectors on continuous profile of radioactive sources, allowing calculate the dose rate at any position of the virtual environment. Thus, this work can assist in the training of security officers, as well as in evaluating the radiological safety of the nuclear site

Chelles, Daniel

Gonçalves, Deise

Machado, Daniel

Mól, Antônio Carlos de Abreu

Santo, André Cotelli

Carpe dIEN

2013 International Nuclear Atlantic Conference - INAC 2013 
Recife, PE, Brazil, November 24-29, 2013 
ASSOCIAÇÃO BRASILEIRA DE ENERGIA NUCLEAR - ABEN 
ISBN: 978-85-99141-05-2 
 
 
VIRTUAL DOSIMETRY APPLIED TO THE PHYSICAL SECURITY OF 
A NUCLEAR INSTALLATION 
 
André Cotelli do E. Santo
1
, Antônio C. A. Mól
2 
, Daniel M. Machado
3
, Daniel R. 
Chelles
4
 and Deise G. S. Gonçalves
5 
 
1,2,3,4,5
 Instituto de Engenharia (IEN / CNEN - RJ) 
Rua Hélio de Almeida, 75 
Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ 
cotelli.andre@gmail.com
1
, mol@ien.gov.br
2 
,  machado.mol@gmail.com
3
, daniel.chelles@gmail.com
4
, 
deise.galvao@gmail.com
5
 
 
 
 
ABSTRACT 
 
An important activity to be held in radiation protection is the location of radioactive sources. The present work 
was devoted to the development of a virtual dosimetry tool for locating and detecting such sources. To this end, 
was created a three-dimensional virtual model of the Instituto de Engenharia Nuclear – IEN, endowed with 
virtual characters (avatars), capable of move and interact with the environment, radiation detectors (fixed and 
mobile) and radioactive sources. Aiming to assist in planning physical security of nuclear installations, the tool 
developed allows the detection simulation of individuals carrying radioactive sources through detectors installed 
at strategic points of the site. In addition, it is possible to detect and locate sources by handling portable 
detectors, operated by characters within the virtual environment. 
The results obtained show the behavior of the radiation detectors on continuous profile of radioactive sources, 
allowing calculate the dose rate at any position of the virtual environment. Thus, this work can assist in the 
training of security officers, as well as in evaluating the radiological safety of the nuclear site. 
 
 
1. INTRODUCTION 
 
The physical security of nuclear installations has been a constant concern of the International 
Atomic Energy Agency (IAEA). Through reports and norms defined in the periodic planning 
of nuclear security [1] the IAEA guides the nuclear sites more intensely commits to control 
and security of its radioactive materials.   
To promote greater efficiency of the systems of control of these materials training of the 
teams of security of the nuclear installations is become fulfilled periodically. One way to help 
these trainings is the inclusion of new tools of computer simulations based on immersive 
virtual environments [2]. In the nuclear area some works already had demonstrated that such 
tools can assist in the training in nuclear installations [2, 3, 4]. Virtual environments make 
possible the qualification for operational procedures without the necessity to display the users 
to the taxes of ionizing radiation. Other works also show the contribution of the virtual reality 
in the nuclear area, as the CIPRES [5], developed for the IBERINCO (Iberdrola Ingenieria y 
Consultoria) and for the Polytechnic Universidad of Valence, that allows the training of 
operators of nuclear installations simulating operations of fuel recharge; The Vrdose [6] is a 
tool capable to show the distribution of the dose tax and to supply estimate of occupational 
doses scenarios of work in nuclear installations. The exposition of human beings the raised 
INAC 2013, Recife, PE, Brazil. 
 
doses of radiation cause damages to the health due to the somatic and genetic effect produced 
by the ionizing radiations [7, 8]. Therefore the use of computational systems is justified still 
more as training tools, calculating only a virtual exposition of ionizing radiation instead a real 
one. A way to produce computational environments virtual is by means of game engines - 
tools for the production of games, that already had revealed great assistant in the 
development of simulation systems [9]. The use of core of the game for simulation systems 
opened a new area called serious games. Different works demonstrate the applicability of the 
core of the game in this context [10, 11, 12]. Many cases are directed to the training of 
emergency situations [13, 14]. In the nuclear area, the virtual reality has been used mainly in 
the simulation of operations in installations with levels of radiation above of the natural 
standard. In this context, therefore, this work presents a methodology based on nucleus of 
games for the creation of measurements of virtual radiation, creating the possibility of if 
implementing, in the virtual tools of simulation, portable and mobile virtual detectors of 
radiation. As application of this work, detectors were inserted into a virtual nuclear facility 
physical security procedures are tested. The virtual detectors also make possible the 
measurement and the training of diverse operations in the nuclear area, as for example the 
training of radioprotection teams.  
 
 
2. DOSIMETRY  
 
The determination of the tax of exposition (dose-rate) to the radiation in determined point or 
environment is understood as dosimetry. This rate consists of the relation between the interval 
of time and the dose of exposition. Rate of exposition is the reason between all the braked 
electron loads in a volume ∆V of air (in NTP), being these produced by interaction of rays-x 
or rays-γ with the mass ∆m of air of the volume in question. [8]. 
 
To express the dose, the unit used currently is Gray (Gy), defined as the dose of radiation 
absorbed for a portion of material, that corresponds to one joule for kilogram. However, a 
unit of measure generally used in real measurements is the tax of counting for unit of time, 
CPS (counts to per second), correspondent the rate of events registered in measurements, 
being this the unit used in the present work. 
 
The dosimetry norms establish acceptable limits of dose of radiation for the environment and 
the beings livings creature. In accordance with principle ALARA (As Low As Reasonably 
Achievable) (ICRP Publication 60, 1990), radiation exposure should only occur when it is 
really necessary, and must be so low when reasonable practicable, guaranteeing thus the 
observance of the safe limits of exposition, preventing a harmful dose to the individual. 
2.1. Radiation Detectors  
 
Detectors of radiation are devices by means of which it is possible to identify the presence of 
radiation in the environment, as well as measure its intensity and energy, making possible the 
detention and localization of radioactive sources. These devices can be found in diverse 
configurations - as much in fixed or mobile (portable) formats. 
 
For proper use of radiation detectors, it is necessary that the security agents are trained to 
handle the instrument and also for the correct interpretation of the data supplied for the 
readings of this. Such training needs careful planning, therefore, beyond involving high costs, 
INAC 2013, Recife, PE, Brazil. 
 
they can represent risks to the health of the Individuals Occupationally Exposed - IOE, 
affecting its limit of annual dose. 
 
 
3 . VIRTUAL REALITY AND GAME ENGINES 
 
One understands by Virtual Reality (VR) the set of techniques, technologies and interfaces 
destined to supply to the user the sensation of integration with the computational system and 
to make possible the immersion of this in the virtual environment (Burdea and Philippe, 
1994). With this intention, the VR uses three-dimensional interactions in real time, 
environments and computational equipment, allowing that the user has the sensation of if 
relating of actual form with the applications. 
 
Game engines are programs destined the production of electronic games. For this, these 
programs centralize diverse libraries and necessary functions to the development, simplifying 
for the programmer fast access to the tools required to the creation of the games and the 
graphical applications. Some of the functionalities frequently found in game engines are, for 
example, engine of game properly said, rendering of graphs in two and three dimensions, 
physics engine, detention of collisions, supported to artificial intelligence and different 
programming languages, etc. 
 
 
4. METHODOLOGY 
For accomplishment of this work a virtual model of the Instituto de Engenharia Nuclear 
(IEN) was developed, located in the Ilha do Fundão - Rio De Janeiro - Brazil. Using the tool 
Autodesk 3ds Max was made the modeling in three dimensions of the pertaining installations 
to the institute and, through the engine of Unity game 3D created the virtual environment in 
which the simulations will be carried through. 
 
With more details, they follow described the main tools used in the present work. 
4.1.  Autodesk 3ds Max 
 
The Autodesk 3ds Max consists of a software destined to the three-dimensional modeling, 
making possible the creation, animation and rendering of directed models the diverse 
applications of virtual reality, as virtual games, mockups, cinema, animations, etc [17]. Using 
this tool was developed the scenario used in this serious game, in accordance with the real 
installations of the Instituto de Engenharia Nuclear (IEN). The modeling respected the 
measures and ratio of the institute, aiming at to provide to the user one better immersion in 
the simulations.  The figure to follow presented consists of the image of building of the IEN 
shaped through 3ds Max. For accomplishment of the present work it was used version 2013. 
 
INAC 2013, Recife, PE, Brazil. 
 
 
 
Figure 1:  Modeling of building of the IEN in 3ds Max. 
 
4.2.  Unity 3D 
 
The Unity 3D consists of a robust engine of three-dimensional game, allied the diverse 
functions auxiliary for the content development 3D. It is presented as a tool multiplatform 
and multilanguage programming  (it supports C#, JavaScript and Boo) [15, 16]. It possesses 
vast documentation and active community, facilitating the learning. 
 
The development of the present work was based on this tool, that makes possible the creation 
of the necessary scenarios of avatars interacting with the environment, the importation of 
objects shaped in the Autodesk 3ds Max, programming of the radioactive sources and the 
functioning of the virtual dosemeters (fixed and mobile). 
 
The programming language used for accomplishment of implementations inside of this 
nucleus of game was C#, pertaining to Framework .NET, chosen for its simplicity and 
robustness, being object-oriented programming and strong typing. 
INAC 2013, Recife, PE, Brazil. 
 
 
 
Figure 2:  IEN shaped in the Unity 3D. 
 
 
 
5. RESULTS  
 
It was carried through the virtual environment, developed in this study, a comparative 
analysis between real dose-rates, measures in the terrain of the Instituto de Engenharia 
Nuclear, and dose-rates gotten in the virtual simulations. 
 
The Monitor Rejects Hospital MRH 7029 in set with the scintillation probe SCT 7026 was 
used. In the first, the average value of referring rates of dose to background (present value in 
the environment of natural form, without interference of external sources) of the institute was 
gotten, identified in 140CPS. At as a moment, diverse measurements proceeding from the 
insertion of a radioactive source in the environment had been collected. The table to follow 
supplies the values gotten in the experiment. 
 
Source Distance Rate of Counts 
120µCi 
1m 
572.90 CPS 
572.80 CPS 
573.20 CPS 
573.10 CPS 
573.10 CPS 
2m 
275.50 CPS 
275.50 CPS 
275.30 CPS 
275.20 CPS 
274.90 CPS 
a.  Dose rates measured in IEN. 
 
 
 
INAC 2013, Recife, PE, Brazil. 
 
The average value of dose rate for a source of 120µCi, to a distance of 1m, was of 
573.02CPS, and the average value of this rate with the same sample, at a distance of 2m, is of 
275.28CPS. Deducting background, they are had, respectively, rates of doses of 433.02CPS 
and 138.28CPS. 
 
In the virtual environment, from the gotten experimentally values, it was configured activity 
of the source in 573.02CPS, considering the inserted radioactive source in the environment in 
set with the existing activity of background in the Instituto de Engenharia Nuclear. The table 
that follows provides values gotten from the virtual simulation. 
 
 
Rate of Counts Distance Dose Received 
573.02CPS 
1.037924m 531.9102CPS 
1.055892m 513.9619CPS 
1.061809m 508.2499CPS 
1.065830m 504.4222CPS 
1.214441m 388.5235CPS 
1.226295m 381.0485CPS 
1.227114m 380.5399CPS 
1.622518m 217.6662CPS 
1.869039m 164.0336CPS 
2.077595m 132.7541CPS 
b.  Doses received by the avatar in the virtual environment. 
 
 
The figures that follow show the developed virtual environment, allowing to the visualization 
of the dose-rate in accordance with the localization of avatar in the environment. 
  
 
    
 
   Figure 3: Mobile dosimeter.         Figure 4:  Fixed dosimeter. 
INAC 2013, Recife, PE, Brazil. 
 
The tool produced in this study allow the accomplishment simulations to identify the 
environmental radiation location for both fixed source (located or abandoned in the site), as 
for identification of sources in movement, that is, perception of the attempt of removal of 
radioactive sources of a nuclear site. 
 
 
6. CONCLUSIONS  
 
The present work demonstrated the use of the Virtual Reality in the development of a tool of 
virtual dosimetry destined to the localization and detention of radioactive sources, with the 
objective of assisting in the planning of the safety level of nuclear installations. The 
visualization and the organization of strategies could be facilitated with the use of such tool, 
as well as the use of this for accomplishment of training and simulation of protection. Future 
improvements as the internal modeling of the building and the environment around of the 
IEN will be able to become this more efficient tool. 
 
 
ACKNOWLEDGMENTS 
 
This research was sponsored by Coordenação de Aperfeiçoamento de Pessoal de Nível 
Superior – CAPES and Conselho Nacional de desenvolvimento Científico e Tecnológico - 
CNPq. Our thanks also to the Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro - 
FAPERJ and Comissão Nacional de Energia Nuclear - CNEN, that, through the Instituto de 
Engenharia Nuclear - IEN, has provided all necessary resources to the development of this 
work. 
 
 
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Virtual dosimetry applied to the physical security of a nuclear installation

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Virtual dosimetry applied to the physical security of a nuclear installation

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