978-1-61942-132-5_ch1

8/14/2019 978-1-61942-132-5_ch1

1/56

8/14/2019 978-1-61942-132-5_ch1

2/56

8/14/2019 978-1-61942-132-5_ch1

3/56

PHYSICS RESEARCH AND TECHNOLOGY

DIGITAL CONTROL SYSTEMSIMULATION FOR NUCLEAR

REACTOR NEUTRONIC

PARAMETERS

No part of this digital document may be reproduced, stored in a retrieval system or transmitted commercially

in any form or by any means. The publisher has taken reasonable care in the preparation of this digitaldocument, but makes no expressed or implied warranty of any kind and assumes no responsibility for any

errors or omissions. No liability is assumed for incidental or consequential damages in connection with or

arising out of information contained herein. This digital document is sold with the clear understanding that

the publisher is not engaged in rendering legal, medical or any other professional services.

8/14/2019 978-1-61942-132-5_ch1

4/56

PHYSICS RESEARCHAND TECHNOLOGY

Additional E-books in this series can be found on Novas website

under the E-book tab.

8/14/2019 978-1-61942-132-5_ch1

5/56

PHYSICS RESEARCH AND TECHNOLOGY

DIGITAL CONTROL SYSTEMSIMULATION FOR NUCLEAR

REACTOR NEUTRONICPARAMETERS

AMIR ZACARIAS MESQUITAANTNIO JUSCELINO PINTO

CLDOLA CSSIA OLIVEIRA DE TELLOAND

FERNANDO SOARES LAMEIRAS

Nova Science Publishers, Inc.

New York

8/14/2019 978-1-61942-132-5_ch1

6/56

Copyright 2012 by Nova Science Publishers, Inc.

All rights reserved.No part of this book may be reproduced, stored in a retrievalsystem or transmitted in any form or by any means: electronic, electrostatic,

magnetic, tape, mechanical photocopying, recording or otherwise without the written

permission of the Publisher.

For permission to use material from this book please contact us:

Telephone 631-231-7269; Fax 631-231-8175

Web Site: http://www.novapublishers.com

NOTICE TO THE READERThe Publisher has taken reasonable care in the preparation of this book, but makes no

expressed or implied warranty of any kind and assumes no responsibility for any

errors or omissions. No liability is assumed for incidental or consequential damages

in connection with or arising out of information contained in this book. The Publisher

shall not be liable for any special, consequential, or exemplary damages resulting, in

whole or in part, from the readers use of, or reliance upon, this material. Any parts of

this book based on government reports are so indicated and copyright is claimed for

those parts to the extent applicable to compilations of such works.

Independent verification should be sought for any data, advice or recommendations

contained in this book. In addition, no responsibility is assumed by the publisher for

any injury and/or damage to persons or property arising from any methods, products,

instructions, ideas or otherwise contained in this publication.

This publication is designed to provide accurate and authoritative information with

regard to the subject matter covered herein. It is sold with the clear understanding

that the Publisher is not engaged in rendering legal or any other professional services.

If legal or any other expert assistance is required, the services of a competent person

should be sought. FROM A DECLARATION OF PARTICIPANTS JOINTLY

ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION

AND A COMMITTEE OF PUBLISHERS.

Additional color graphics may be available in the e-book version of this book.

LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA

ISBN: 978-1-61942-132-5

Published by Nova Science Publishers, Inc. New York

8/14/2019 978-1-61942-132-5_ch1

7/56

CONTENTS

Preface viiChapter 1 Introduction 1Chapter 2 The IPR-R1 TRIGA Reactor 5Chapter 3 TRIGA Nuclear Reactor Kinetics and Control 9Chapter 4 Digital Instrumentation for Nuclear Reactors 23Chapter 5 Neutronic Parameters to be Simulated 27Chapter 6 Conclusion 37Acknowledgments 39References 41Index 43

8/14/2019 978-1-61942-132-5_ch1

8/56

8/14/2019 978-1-61942-132-5_ch1

9/56

PREFACE

The International Atomic Energy Agency recommends the use of

safety and friendly interfaces for monitoring and controlling the

operational parameters of the nuclear reactors (IAEA, 1998, 1999). The

most important variable in the nuclear reactors control is the power

released by fission of the fuel in the core, which is directly proportional

to neutron flux (IAEA, 2008). It was developed a digital system to

simulate the neutron evolution flux and monitor their interaction on the

other operational parameters. The control objective is to bring the reactor

power from its source level (mW) to a few W. It is intended for

education of basic reactor neutronic principles such as the multiplication

factor, criticality, reactivity, period, delayed neutron and control by rods.

The 250 kW IPR-R1 TRIGA research reactor at Nuclear Technology

Development Center - CDTN (Belo Horizonte/Brazil) was used as

reference. TRIGA reactors, developed by General Atomics (GA), are themost widely used research reactor in the world. They are cooled by light

water under natural convection and are characterized by being inherently

safe.

The simulation system was developed using the LabVIEW

(Laboratory Virtual Instruments Engineering Workbench) software,

considering the modern concept of virtual instruments (VIs) using

electronic processor and visual interface in video monitor (National

Instruments, 2007). The main purpose of the system is to provide trainingtools for students and reactor operator, allowing to study, to observe, and

to analyze the behavior, and the tendency of some processes that occur in

the reactor using a user-friendly operator interface. Some scenarios are

presented to demonstrate that it is possible to know the behavior of some

8/14/2019 978-1-61942-132-5_ch1

10/56

Amir Zacarias Mesquita, Antnio Juscelino Pinto et al.viii

variables from knowledge of input parameters. The TRIGA simulator

system will allow the study of parameters, which affect the reactor

operation, without the necessity of using the facility.

8/14/2019 978-1-61942-132-5_ch1

11/56

Chapter 1

INTRODUCTION

Rising concerns about global warming and energy security have

spurred a revival of interest in nuclear energy, giving birth to a nuclear

power renaissance in countries the world over. As humankind seeks

abundant and environmentally responsible energy in the coming decades,

the renaissance of nuclear power will undoubtedly become reality as it isa proven technology and has the potential to generate virtually limitless

energy with no greenhouse gas emissions during operations. In addition,

basic research and nuclear technology applications in chemistry, physics,

biology, agriculture, health and engineering have been showing their

importance in the innovation of nuclear technology applications with

sustainability.

Nuclear reactor instrumentation is designed so as to emphasize the

reliability, redundancy and diversity of control systems. Powermonitoring in nuclear reactors is of crucial importance with respect to

safety and efficient operation. Since the first criticality of a nuclear

reactor carried out by Fermi and collaborators on December 2, 1942, at

the Chicago University, there has been concern about safely monitoring

the parameters involved in the chain reaction.

Nuclear reactor simulation involves mainly neutronic (neutron

physic) and thermal hydraulic (fluid and heat transfer). The dynamic

behavior of a reactor is associated with an important property known asits reactivity. This property changes when the fuel temperatures are

changed. The changes of reactivity occasioned by fuel changes of

temperatures form the effect that is called the temperature coefficient of

reactivity. For the IPR-R1 TRIGA reactor, this effect appears when the

8/14/2019 978-1-61942-132-5_ch1

12/56

r

l

t

t

t

Ami

eactor opera

evel, there

imulation w

atts, so o

perational p

imulated by

igure 1. Digit

arameters.

Nuclear

omputers (imulation sy

alidated in t

raphical in

ransparency

isualization

ata is stored

sed for rese

heir relative

esting groun

ontributes t

raining of t

sing the sof

r Zacarias M

es in power

is not the

s developed

nly the ne

rameters lik

this program

al control syst

eactor oper

icroprocessostem describ

e IPR-R1 T

terfaces im

in nuclea

and transmis

and can be

arch reactors

ly low cost

d for the re

the safe

e operation

ware LabVI

esquita, Ant

above nearl

nfluence of

for the reac

utronic par

e the fission

.

m simulation

ting is mov

r) for monitd here has b

IGA resear

lemented

r reactors

ion through

ade availab

can be late

llows resear

ctors of to

nd reliable

l staff. The

W

, where

nio Juscelin

1 kW. For

temperatur

tor operatin

meters we

product pois

for nuclear re

ng toward

ring and coneen develop

h reactor. T

rovide gre

operations.

the internet

le. Develop

applied to l

h reactors t

orrow. The

operation o

reactor sim

the user defi

Pinto et al.

low operati

. In this

at a power

e simulate

oning will al

ctor neutroni

wider use

trolling the pd and exper

e methodol

ater reliabi

Besides

r in the net

ents and in

arger power

provide an

work prese

nuclear re

lator was d

nes the requ

g power

ork, the

of a few

. Other

so not be

f digital

lant. Thementally

gies and

lity and

allowing

orks, the

ovations

reactors.

excellent

ted here

ctors by

eveloped

red final

8/14/2019 978-1-61942-132-5_ch1

13/56

Introduction 3

power, and some of the plant and controller parameters were graphically

and numerically available to the operator (National Instruments, 2007).

Figure 1 shows two user interface of the simulation system in two

computer video screens.

8/14/2019 978-1-61942-132-5_ch1

14/56

8/14/2019 978-1-61942-132-5_ch1

15/56

Chapter 2

THE IPR-R1TRIGAREACTOR

The IPR-R1 TRIGA (Instituto de Pesquisas Radiativas- Reactor 1,

Training Research Isotope General Atomic) reactor, located at the

Nuclear Technology Development Center - CDTN (Belo

Horizonte/Brazil), is a typical TRIGA Mark I light-water and open-pool

type reactor. The fuel elements in the reactor core are cooled by water

natural circulation. The heat removal capability of this process is great

enough for safety reasons at the current maximum 250 kW power level

configuration. However, a heat removal system is provided for removing

heat from the reactor pool water. The water is pumped through a heat

exchanger, where the heat is transferred from the primary to the

secondary loop. The secondary loop water is cooled in an external

cooling tower.

TRIGA reactors are the most widely used research reactor in theworld. There is an installed base of over sixty-five facilities in twenty-

four countries on five continents. General Atomics (GA), the supplier of

TRIGA research reactors, since the late 1950s, continues to design and

install TRIGA reactors around the world and has built TRIGA reactors in

a variety of configurations and capabilities, with steady state thermal

power levels ranging from 100 kW to 16 MW. TRIGA reactors are used

in many diverse applications, including production of radioisotopes for

medicine and industry, treatment of tumors, nondestructive testing, basicresearch on the properties of matter, and for education and training. The

TRIGA reactor is the only nuclear reactor in this category that offers true

"inherent safety, rather than relying on "engineered safety." It is

8/14/2019 978-1-61942-132-5_ch1

16/56

Ami

ossible due

uel, which

lexibility in

tomics, 201

ore with the

igure 2. The I

The IP

ctivation an

bout 6m hei

hielding. T

r Zacarias M

o the unique

rovides unri

sitting, wi

0). Figure 2

IPR-R1 TRI

PR-R1 TRIG

-1 TRIGA

lysis. The c

ht and 2m

e core has

esquita, Ant

properties o

aled safety

th minimal

shows two

A reactor i

nuclear reac

is used for

re is placed

iameter, abl

an annular

nio Juscelin

GA's urani

characteristi

environme

photograph

operation.

or.

training, r

at the botto

to assure a

raphite refl

Pinto et al.

m-zirconiu

s, which al

tal effects

of the pool

search and

of an ope

adequate ra

ector and c

hydride

o permit

(General

and the

neutron

tank of

dioactive

lindrical

8/14/2019 978-1-61942-132-5_ch1

17/56

The IPR-R1 TRIGA Reactor 7

configuration of six rings (A, B, C, D, E, F) with 90 positions able to

host either fuel rods or other components like control rods, graphite

dummies (mobile reflector), irradiating and measurement channels (e.g.,

central thimble alias A ring). A simplified view of the TRIGA current

configuration is show in Figure 3; anyway there is a very high number of

reactor loading configurations, so that it is possible to obtain the sub-

critical level required simply loading/unloading fuel rods from the core.

The prototypical cylindrical fuel elements are a homogeneous alloy of

zirconium hydride (neutron moderator) and uranium enriched at 20% in

235U. The reactor core has 58 aluminum-clad fuel elements and fivestainless steel-clad fuel elements. One of these steel-clad fuel elementsisinstrumented with three thermocouples along its centerline. This

instrumented fuel element was inserted by Mesquita (2005) in the reactor

core in order to evaluate the thermal hydraulic performance of the IPR-

R1 reactor. The fuel rod has about 3.5 cm diameter; the active length is

about 37 cm closed by graphite slugs at the top and bottom ends, which

act as axial reflector. The moderating effects are carried out mainly by

the zirconium hydride in the mixture and on a smaller scale by lightwater coolant. The characteristic of the fuel elements gives a very high

negative prompt temperature coefficient and is the main reason of the

high inherent safety behavior of the TRIGA reactors. The power level of

the reactor is controlled with three independent control rods: a

Regulating rod, a Shim rod, and a Safety rod.

Power monitoring of nuclear reactors is always done by means of

nuclear detectors, which are calibrated by thermal methods. In the IPR-

R1 reactor, four neutron-sensitive chambers are mounted around the

reactor core for flux measurement. The departure channel consists of a

fission counter with a pulse amplifier that a logarithmic count rate

circuit. The logarithmic channel consists of a compensated ion chamber,

whose signal is the input to a logarithmic amplifier, which gives a

logarithmic power indication from less than 0.1W to full power. The

linear channel consists of a compensated ion chamber, whose signal is

the input to a sensitive amplifier and recorder with a range switch, which

gives accurate power information from source level to full power on a

linear recorder. The percent channel consists of an uncompensated ion

chamber, whose signal is the input to a power level monitor circuit and

meter, which is calibrated in percentage of full power.

8/14/2019 978-1-61942-132-5_ch1

18/56

Ami

igure 3. Core

r Zacarias M

configuration

esquita, Ant

of IPR-R1 TR

nio Juscelin

IGA research

Pinto et al.

reactor.

8/14/2019 978-1-61942-132-5_ch1

19/56

Chapter 3

TRIGANUCLEAR REACTORKINETICS AND CONTROL

An overview of the basic neutronic parameters related to operation

of TRIGA type reactors, which will be simulated by the digital system

developed, will be given. The text has been adapted mainly from theprogram prepared for the International Atomic Energy Agency (IAEA)

by Bck and Villa (2004) and for the operator training course at Nuclear

Technology Development Center (CDTN, 1997).

NEUTRON FLUX

Prior to absorption, the neutrons in a reactor move about incomplicated paths as the result of repeated nuclear collisions. To a first

approximation, the overall effect of these collisions is that neutrons

undergo a kind of diffusion in the reactor medium, one similar to gas

diffusion (Lamarsh and Baratta, 2001). As a result, a neutron path

consists of many straight line segments joining the points of collision

(random motion). The combined effect of billions of neutrons darting in

all directions in a random motion is a cloudlike diffusion of neutrons

throughout the reactor material. Neutron flux is simply a term used todescribe the neutron cloud.

In the reactor volume V, there are a neutrons population N. The

neutrons have been assumed to be monoenergetic, so the neutron density,

n, is defined as:

8/14/2019 978-1-61942-132-5_ch1

20/56

Amir Zacarias Mesquita, Antnio Juscelino Pinto et al.10

V

Nn

= [ncm

-3

] (1)

The neutron flux is the number of neutrons in 1 cubic centimeter

multiplied by their average velocity:

= nv [ncm-2

s-1

] (2)

THE FISSION CHAIN REACTION,MULTIPLICATION FACTOR

The importance of fission, from the standpoint of the utilization of

nuclear energy, lies in three facts. First, the process is associated with the

release of a large amount of energy per unit mass of nuclear fuel. Second,

the fission reaction, which is initiated by neutrons, is accompanied by the

releases an average of 2.5 neutrons (fission of a

235

U). Third,approximately 0.73 % of the neutrons have delayed emission that

originate in the fission products; they reduce the rate of neutrons increase

allowing the chain reaction control. It is the combination of these three

circumstances that makes possible the design of nuclear reactor in which

a self-sustaining fission chain reaction occurs with the continuous release

of energy. Once the fission reaction has been started in a few nuclei by

means of an external source of neutrons, it can be maintained in other

nuclei by the neutrons produced in the reaction (Glasstone and Sesonske,

1994).

Such a chain reaction can be described quantitatively in terms of the

multiplication factor (k). This is defined as the ratio of the number of

fissions in one generation divided by the number of fissions in the

preceding generation, or:

k=number of fissions in one generation (Ni)

number of fissions in preceding generation (Ni-1)

If the number of neutrons from one generation to the next are exactly

equal, then k = 1, the reactor is critical and the chain reaction will

continue at a constant level. A reactor can be critical at any power level.

8/14/2019 978-1-61942-132-5_ch1

21/56

TRIGA Nuclear Reactor Kinetics and Control 11

If succeeding generations of neutrons are causing a decreasing number of

fissions between generations, then k < 1, the reactor is subcritical, and

the power level of the reactor will be decreasing. If succeeding

generations of neutrons are resulting in an increase of the number of

fissions between generations, then k > 1, the reactor is supercritical, and

the power level of the reactor will be increasing. The power level of a

reactor can only change if the reactor is subcritical (power will decrease)

or if the reactor is supercritical (power will increase). Maintaining reactor

power at a prescribed value, or changing reactor power to a new value at

a prescribed rate, are functions that must be performed by the reactorcontrol system. The reactor control system changes the value of k by

changing what happens to the neutrons during their life time, i.e., from

the time they are born until they either escape from the reactor or are

absorbed. For a critical reactor for each neutron born, exactly one

neutron must cause fission in the next generation. There are six factors

that govern the production, leakage and absorption neutrons, and enable

the quantitative description of the components that govern the

multiplication factor in the neutron cycle.The balance between the neutrons production and their absorption

in the core and leakage out of the core determines the value of the

multiplication factor. If the leakage is small enough to be neglected, the

multiplication factor depends only upon the balance between production

and absorption and is called the infinite multiplication factor, k (an

infinitely large core can have no leakage). When the leakage is included,

the factor is called the effective multiplication factor (keff). By definition,

the multiplication constants keffand kare dimensionless numbers (Bckand Villa, 2004).

REACTIVITY

Under normal operating conditions, a reactor is operating at or very

near criticality, i.e., kis nearly equal to 1.0. Small deviations of kabove

or below 1 will result in significant changes in reactor power. Under

these circumstances, it is more practical to work in terms of the amount

by which kdeviates from unity, instead of quoting several zeros before

we reach any significant digits after 1. The term that has been found

useful in reactor analysis to describe the behavior of the reactor when k

8/14/2019 978-1-61942-132-5_ch1

22/56

8/14/2019 978-1-61942-132-5_ch1

23/56


automatically in the event that potentially unsafe conditions should arise

(Fadaei and Setayeshi, 2009).

An important feature of a nuclear reactor that has bearing on the

control system design is that, in most reactors, the fuel supply cannot be

continuously replaced as it is consumed. Consequently, at the beginning

of each operational period, the reactor core mostly contains all the fuel

(fissile material) that will be required to produce a predetermined

quantity of energy. Furthermore, additional fuel is necessary to allow for

the decrease in neutron multiplication arising from fission-product

poisons and from the high operating temperature (the negativetemperature coefficient). When the reactor core is mounted before the

start of operation, it includes a considerable amount of excess fuel (about

2530%), more than required value for criticality in the initial cold

condition. The additional fissile material in the core is said to represent

built-in (or excess) reactivity. An essential requirement of the control

system is that it must be capable of introducing enough negative

reactivity to compensate for the positive reactivity at initial startup of the

reactor (Glasstone and Sesonke, 1994). The power level of the reactordepends on the macroscopic fission cross-section and the neutron flux.

Over a short time interval, the cross-section remains essentially constant,

although it may not have the same value at all locations in the core.

Hence, the power level at any instant can be considered proportional to

the neutron flux.

The loss of reactivity of the system due to the burn up of the fuel, the

production of isotopes, changes in temperature, and so on, should be

compensated. In most reactors, as the TRIGA reactor, this is

accomplished by control rods, which are also used to start up and shut

down a reactor or change its power level (Lamarsh and Baratta, 2001).

The calculation of the reactivity worth of control elements and groups the

effects of such elements on the power distribution in the core of a nuclear

reactor constitute a very important facet of nuclear reactor design. When

a control rod is inserted in a reactor core, it absorbs neutrons in its

vicinity and thereby produces a distortion of the neutron flux distribution.

The effect of absorber rods can be explained by considering a reactor in

which the maximum neutron flux is maintained constant, with or withoutcontrol rod insertion.

The adjustment of neutron flux or power level in the reactor is

achieved by movement of the control rods. They consist of a container

8/14/2019 978-1-61942-132-5_ch1

24/56


filled with a strongly neutron-absorbing medium such as boron,

cadmium, gadolinium, or hafnium. The rod has the property of change

multiplication factor (k), depending on whether the rod is inserted or

withdrawn from the core. This change in k results in a change in the

reactivity of the core. The worth of a control rod is, therefore, directly

related to its effect on reactivity and is usually measured in the same

units (Bck and Villa, 2004).

The physical effects produced by a control rod can be visualized in

the following way. If a thermal neutron, in the course of its diffusion

through the core, enters the absorbing boron, for example, its chance ofgetting through is almost zero. For practical purposes, boron is a perfect

absorber for thermal neutrons, in that all neutrons that reach the surface

are lost. Suppose a single absorber rod is inserted at the center of a

uniform reactor core; the radial neutron flux distribution will be as shown

in Figure 4. It can be seen that the neutron flux is decreased close to the

control rod, but farther out nearer the core boundary, the flux is increased

(Glasstone and Sesonke, 1994). The effectiveness, or worth, of a control

rod depends largely upon the value of the neutron flux at the location ofthe rod. The control rod will have maximum effect if it is placed in the

reactor where the flux is a maximum.

Nuclear reactors must have sufficient excess reactivity to

compensate the negative reactivity feedback effects such as those caused

by the fuel temperature, fuel burn up, fission poisoning production, and

also to allow full power operation for predetermined period of time. To

compensate for this excess reactivity, it is necessary to introduce an

amount of negative reactivity into the core, which one can adjust or

control at will. In the IPR-R1 TRIGA reactor, the reactivity control and

consequently the power level is done by three control rods that can be

inserted into or withdrawn from the core. They are: a Safety rod, a Shim

rod and a Regulating rod.

The variation in the worth of the rod as it is inserted or withdrawn

from the reactor is dependent on the axial flux shape. The flux is

typically less at the top and bottom of the reactor than in the middle.

Therefore, the control rod is worth less at the top and bottom than it is in

the middle during insertion or withdrawal. This behavior is typicallyillustrated in the differential and integral rod worth curves as shown in

Figure 5. The integral control rod worth curve is particularly important in

TRIGA research reactor operation.

8/14/2019 978-1-61942-132-5_ch1

25/56


Figure 4. Effect of a single central control rod on radial neutron flux distribution.

For a reactor that has a large amount of excess reactivity, severalcontrol rods will be required. To gain the full effectiveness of the rods

and a relatively even flux distribution, the rods would need to be

distributed appropriately. The exact amount of reactivity that each

control rod could insert is dependent upon the design of the reactor.

Core excess is the reactivity available that is above that necessary to

achieve criticality. In other words, it is what the reactivity of the system

would be if all of the control rods in the reactor were completely

withdrawn. The core excess of a reactor is constantly changing due tomany of the variables already discussed, such as fuel depletion,

temperature, and fission product poisons. It is also an important

parameter that is routinely assessed to provide assurance that there is

always sufficient negative reactivity in the control rods to shut the reactor

down; even perhaps with one rod or one group of rods stuck out. As

shown earlier, if the core excess is too low then it may not be possible to

go critical during the xenon peak after shutdown.

8/14/2019 978-1-61942-132-5_ch1

26/56


Figure 5. Integral and differential and control rod worth curves.

8/14/2019 978-1-61942-132-5_ch1

27/56


DELAYED

NEUTRONS

One of the most important aspects of the fission process from the

viewpoint of reactor control is the presence of delayed neutrons. A

delayed neutron is a neutron emitted by an excited fission product

nucleus during beta disintegration some appreciable time after the

fission. How long afterward is dependent on the half-life of the delayed

neutron precursor, since the neutron emission itself occurs in a very short

time. The symbol is used to denote the total fraction of delayed

neutrons (Bck and Villa, 2004).

Chart 1. Delayed neutrons fractions from thermalfission of 235U at IPR-R1 TRIGA reactor (CDTN, 1997)

Group

i

Proportion

i(%)

Half-life

ti(s)

Decay Constant

i(s-1)

Energy

Ei(keV)

1 0.022 55 0.013 250

2 0.145 22 0.032 560

3 0.131 6.0 0.12 430

4 0.242 2.2 0.31 620

5 0.083 0.50 1.39 420

6 0.027 0.18 3.85 -

Fraction delayed %65.0i== .

There are six decay chains that are of significance in the emission of

delayed neutrons. (Not all of these chains have been positively

identified.) Correspondingly, delayed neutrons are commonly discussed

as being in six groups. Each of these groups (i) is characterized by a

fractional yield iand a decay constant i. Chart 1 lists the properties of

the six known groups of delayed neutrons emitted during the fission of235

U. The fractional yield i is the number of delayed neutrons in a

reactor operating at steady state, which is due to neutron emission from

decay of fission products (precursors) in group i. The total yield of

delayed neutrons is the sum of the fractional values iover all groups i.

In general, delayed neutrons are more effective than prompt neutronsbecause they are born at somewhat lower energy compared to prompt

(fission) neutrons. Thus, they have a better chance to survive leakage and

resonance absorption. This is accounted for by giving the delayed

8/14/2019 978-1-61942-132-5_ch1

28/56

8/14/2019 978-1-61942-132-5_ch1

29/56


condition is used as the basis for a reactivity unit known as the dollar,

defined by:

Reactivity in dollars =

=$ (4)

The reactivity equivalent to one-hundredth of dollar is one cent. The

value of varies from fuel to fuel, so dollar is not an absolute unit. Due

the intrinsic fuel properties, the TRIGA is the only kind of reactor thatcan suddenly make prompt critical (pulse of neutrons).

REACTOR KINETIC,PERIOD,INHOUR EQUATION

The reactor period is defined as the time required for reactor neutron

flux (or reactor power) to change by a factor of e (about 2.718). The

period (T) is expressed in units of seconds (s). From the definition ofreactor period, it is possible to develop the relationship between reactor

power and reactor period that is expressed by Eq. 5 (CDTN/CNEN,

1997).

N(t) = N0et/T

(5)

Where:

N = transient reactor neutron flux

No= initial reactor neutron flux

T = reactor period (s)

t = time during the reactor transient (s).

The smaller the value of T, the faster the change in reactor power. If

the reactor period is positive, reactor power is increasing. If the reactor

period is negative, reactor power is decreasing.

The study of time-dependent phenomena in nuclear reactor system is

referred to as reactor kinetics or reactor dynamics. Most of the neutrons

emitted in fission appear at the instant of fission (more than 99%), these

are the prompt neutrons. A small fraction of the fission neutrons appears

8/14/2019 978-1-61942-132-5_ch1

30/56

8/14/2019 978-1-61942-132-5_ch1

31/56


presented in a graph. Figure 6 shows the results of such calculations

plotted for the IPR-R1 TRIGA reactor.

Figure 6. Relationship between reactor period and reactivity (CDTN, 1997).

8/14/2019 978-1-61942-132-5_ch1

32/56

8/14/2019 978-1-61942-132-5_ch1

33/56

Chapter 4

DIGITAL INSTRUMENTATIONFOR NUCLEAR REACTORS

Control and instrumentation of nuclear power plants has improved

rapidly and significantly in recent years as demands for reactor safety,

availability, and reliability increased. Development and design ofmodern, highly automated systems have become possible as new

measurement and control methods were introduced together with new

data processing techniques based on recent advances in electronic

components, transducers, and computers. There is now a new generation

of computerized nuclear power plant control systems that meet the high

demands for reactor safety and decrease the risk of accidents. The

experience gained using computers in reactor-control systems and in

monitoring the status of safety systems has shown the benefits that canbe gained from fully computerized shut-down systems. They are reliable,

flexible in design, and give a better man-machine interface.

Microcomputers and their software will dominate future systems.

Computers and their peripherals, e.g., graphical color screens, will

become the major source of information for the reactor operator. The

new digital control includes automatic start-up and shut-down procedures

to reduce risks for potential errors and to improve operational

management. The control methods employed are mainly supervisory

computer control and direct digital control (Sitnikov, 1983).

8/14/2019 978-1-61942-132-5_ch1

34/56


VIRTUAL

INSTRUMENTS

The rapid adoption of the PC in the last 20 years catalyzed a

revolution in instrumentation for test, measurement, and automation. One

major development resulting from the ubiquity of the PC is the concept

of virtual instrumentation, which offers several benefits to engineers and

scientists who require increased productivity, accuracy, and performance.

A virtual instrument (VI) consists of an industry-standard computer or

workstation equipped with powerful application software, cost-effective

hardware such as plug-in boards, and driver software, which togetherperform the functions of traditional instruments. The VI appearance and

operation imitate physical instruments. Traditional hardware

instrumentation systems are made up of pre-defined hardware

components, such as digital multimeters and oscilloscopes. These

systems are more limited in their versatility than virtual instrumentation

systems. The primary difference between hardware instrumentation and

virtual instrumentation is that software is used to replace a large amount

of hardware. Virtual instruments are computer programs that interactwith real world objects by means of sensors and that implement functions

of real or imaginary instruments. They can acquire, simulate and analyze

data. Virtual instruments represent a fundamental shift from traditional

hardware-centered instrumentation systems to software-centered systems

that exploit the computing power, productivity, display, and connectivity

capabilities of popular desktop computers and workstations. Although

the PC and integrated circuit technology have experienced significant

advances in the last two decades, it is software that truly provides theleverage to build on this powerful hardware foundation to create virtual

instruments, providing better ways to innovate and significantly reduce

cost. With virtual instruments, engineers and scientists build

measurement and automation systems that suit their needs exactly (user

defined) instead of being limited by traditional fixed-function

instruments (vendor defined). The synergy between them offers

advantages that cannot be matched by traditional instrumentation

(National Instruments, 2010).

The most popular software used in virtual instrumentation is the

LabVIEW

programs. LabVIEW

(Laboratory Virtual Instruments

Engineering Workbench) contains a comprehensive set of tools for

acquiring analyzing, displaying, and storing data. This software is used in

8/14/2019 978-1-61942-132-5_ch1

35/56

Digital Instrumentation for Nuclear Reactors 25

conventional plants and in some nuclear reactors, replacing the analog

control system with modern, user-friendly digital control (Pederson,

2005). LabVIEW, developed by National Instruments (2007), is an

amazingly intuitive program. It allows you to create programs using a

graphics-based programming language called G. This means there are no

longer lines upon lines of text-based code with hard-to-remember syntax

(e.g., C++, Fortran). You just drag the functions onto the screen and wire

them together. Also, LabVIEWis equipped with some very easy-to-use

functions that take care of the dirty low-level work of configuring the

computer hardware to establish communication between the computerand the instrument.

LabVIEW

software was used, in the work present here, to simulate

the neutronic parameter evolution of nuclear reactor. LabVIEW

VIs

contain three components: the front panel, the block diagram, and the

icon and connector panel. In LabVIEW

, the user builds an interface, or

front panel, with controls and indicators. Controls are knobs, switches,

push buttons, dials, and other input devices. Indicators are graphs,

meters, and other displays that simulate the front panel of a realinstrument. The code and structures to control the front panel objects are

added to the user interface. The block diagram contains this code. The

block diagram resembles a flowchart (National Instruments, 2007).

Digital electronics technology has rapidly taken over the bulk of new

electronic applications because of its vastly increased functionality,

lower cost, improved reliability and reduced maintenance requirements.

Microprocessors have revolutionized the instrumentation and control

systems. With their capability for convenient programming of complex

tasks, they have found applications in a phenomenally wide range of

applications. The extraordinary increase in computing power and the

simultaneous dramatic reduction in cost of computing hardware have

made it possible to develop high-performance plant monitoring and

control systems with a wide range of functions and features. Their most

recognizable feature is user friendly humanmachine interfaces (HMIs)

with graphical displays (IAEA, 1999).

Virtual instruments, by virtue of being PC-based, inherently take

advantage of the benefits from the latest technology incorporated intooff-the-shelf PCs. These advances in technology and performance, which

are quickly closing the gap between stand-alone instruments and PCs,

include powerful processors such as the Pentium i7 and operating

8/14/2019 978-1-61942-132-5_ch1

36/56


systems and technologies such as Microsoft Windows Vista and Seven.

In addition to incorporating powerful features, these platforms also offer

easy access to powerful tools such as the Internet. Traditional

instruments also frequently lack portability, whereas virtual instruments

running on notebooks automatically incorporate their portable nature.

Engineers and scientists whose needs, applications, and requirements

change very quickly need flexibility to create their own solutions. You

can adapt a virtual instrument to your particular needs without having to

replace the entire device because of the application software installed on

the PC and the wide range of available plug-in hardware (NationalInstruments, 2010).

8/14/2019 978-1-61942-132-5_ch1

37/56

Chapter 5

NEUTRONIC PARAMETERSTO BE SIMULATED

The neutronic parameters to be simulated are those that appear in the

reactor startup caused by the control rods movement, leading to neutron

flux multiplication. As mentioned, the reactor reference is the IPR-R1TRIGA research reactor. In this reactor, the reactivity control, and

consequently the power level, is done by three control rods that can be

inserted into or withdrawn from the core. They are: a Safety Rod, a Shim

Rod and a Regulating Rod.

The front panel of the simulator system displays the responses of the

two main power measure channels, the Linear Channel and the

Logarithmic Channel. The reactivity () the period (T) and the inhour

equation are variables derived from these two channels.The boundary conditions are:

The inhour equation is only valid for stable period. The Safety Rod can be moved from position 150 (fully inserted)

to position 890 (totally removed). During reactor operation, this

rod is completely out.

The Shim Rod, during the reactor operation, normally works inan intermediate position. It can be moved from position 161

(fully inserted) to position 890 (totally removed).

The Regulation Rod also works in an intermediate position. Itcan be moved from position 171 (fully inserted) to position 900

(totally removed).

8/14/2019 978-1-61942-132-5_ch1

38/56


The simulation is valid for operations up to a maximum of 1kW. For higher power, the fuel temperature increase causes the

appearance of a negative reactivity in the core, not simulated by

the program. This property is called the "temperature coefficient

of reactivity."

The main VIs developed for the simulator were: the VI that relates

the control rod position with the reactivity inserted in the core

(calibration rod equation), the VI that relates reactor period with

reactivity (inhour curve) and the VI that relates the neutronmultiplication in the Linear Channel and Logarithmic Channel. Some

VIs were developed to manage the program. These instruments were

called "structure events.

ROUTINE STARTUP AND SHUTDOWNOF THE TRIGAREACTOR

The steps that are followed for the routine startup and shutdown the

TRIGA reactor are described here. With the control rods of the reactor

calibrated and a neutron source provided, the reactor might be taken up

to power from its shutdown condition by slowly withdrawing the Safety

rod to its ready position, followed by small stepwise withdrawal of the

Shim rod and the Regulating rod, maintaining approximately

symmetrical positions for this two rods. The multiplication of the

neutrons is followed with the period meter, the fission chamber (StartupChannel) and the ionization chamber (Logarithmic Channel), while the

reactor is still subcritical. If the motion of the shim or regulation rod

under withdrawal is stopped while the rector is in this condition, the

meters will come to rest and the period meter will return to the infinite-

period position (Hoag, 1958).

The slow adjustment of the shim rod and the regulating rod by the

operator is continued. There will come a time when, with the rods

stationary, the period meter not indicate an infinite period but somefinite, large value. This indicates that the reactor is slightly supercritical.

The shim rod positions should then be left as they are, and the regulating

rod adjusted slightly to set the period to a moderate value. In this state,

the reactor power is slowly rising and may be followed by the meter of

8/14/2019 978-1-61942-132-5_ch1

39/56

Neutronic Parameters to be Simulated 29

the logarithmic channel and later by the linear channel. When the desired

power level is obtained, the regulating rod should be slightly inserted

until the power level remains constant and the period meter returns to the

infinite-period position. The reactor may be shut down by one or more

methods. To shutdown the reactor, the scram button is pressed, thereby

releasing the control rods. They will then quickly insert the rods by

gravity and shut the rector down (Hoag, 1958).

DEVELOPMENT OF THE SIMULATOR

The system simulator design followed the methodology shown in the

flowchart of Figure 7 (Pinto, 2010). After being selected, the parameters

were created several virtual instruments (VIs) and for each VI, had

developed a LabVIEWblock diagram.

THE CONTROL RODSWORTH VI

The determination of the reactivity worth of individual control

elements and the effects of such elements on the power distribution in the

core is important to the safe and efficient operation of a nuclear reactor.

Once a control rod is calibrated, it is possible to evaluate the magnitude

of other reactivity changes by comparing the critical rod positions before

and after the change. All three-control rods are calibrated by the positiveperiod method. The method consists of withdrawing the control rod from

a known critical position through a small distance. This adds a positive

reactivity to the system, and the reactor power increases in a exponential

manner with time and establishes a stable period that is measured using

the doubling time, that is the time required for the power to increase by a

factor of two. Each successive step is compensated by lowering the other

control rod just enough to reestablish criticality. The reactivity associated

with the measurement is gotten from the graphical form of the inhourequation that gives the relationship between reactivity and the stable

reactor period.

8/14/2019 978-1-61942-132-5_ch1

40/56


Figure 7. Steps followed in developing the simulator system.

The experimental data obtained in the control rods calibration and

the integral fitted worth curves of the Regulating, Shim and Safety

control rods as a function of their positions are shown graphically in

Figure 8, Figure 9 and Figure 10, respectively. The equationsrepresenting the fitted model, and the coefficients of determination R

2,

that confirm the goodness of the fit are also shown in the figures. The

integral control rod worth curve is particularly important in research

8/14/2019 978-1-61942-132-5_ch1

41/56

reactor oper

afety contro

.8 cents, res

igure 8. Reac

igure 9. Reac

Neutron

tion The m

l rod worth f

ectively (M

ivity as functi

ivity as functi

c Parameter

asured val

r the IPR-R

squita and S

on of insertio

on of insertio

to be Simul

es of the

TRIGA rea

ouza, 2010).

of Regulatio

of Shim cont

ted

egulating, S

ctor were 0.

control rod.

ol rod.

31

him and

, 3.1 and

8/14/2019 978-1-61942-132-5_ch1

42/56

r

t

Ami2

igure 10. Rea

It was bu

ods worth

rogram. In to simulate t

ositions. Fi

laces where

osition step.

igure 11. Rea

r Zacarias M

ctivity as func

ilding the V

urves were

is VI, theree reactivity

ure 11 show

the user ente

ctivity versus

esquita, Ant

ion of inserti

named Co

added to th

are switchesnserted into

the graphi

rs with the v

egulating ro

nio Juscelin

n of the Safet

trol Rods

e block dia

and indicatthe core as

interface fo

riables del

position.

Pinto et al.

control rod.

orth and th

ram of La

rs that allofunction of

r Regulating

a reactivity

e control

VIEW

the userthe rods

Rod and

and rod

8/14/2019 978-1-61942-132-5_ch1

43/56

I

(

(

t

The rela

PR-R1 TRI

peration, is

Equation 6);

rogram.

For IPR-

=100s), t

ultiplicatio

e determin

onsidered t

mitted durin

he graphic i

igure 12. Inh

Neutron

THE I

ionship bet

A reactor,

given by t

this equati

R1TRIGA r

e delayed n

factor (k

d when the

e properties

g the fission

terface of th

ur equation c

c Parameter

HOURE

een the rea

hich is not

e inhour eq

n was insert

actor: the n

eutron fracti

1 and k

reactivity i

of the six k

of235

U pres

program.

rve.

to be Simul

UATION

tivity () a

far above th

uation show

ed into the

utron gener

n and its d

.001) is kn

known an

own group

ented in Cha

ted

VI

d period (T

critical con

n in the Se

abVIEW

tion averag

cay constant

wn so the p

vice vers

of delayed

rt 1. Figure

33

) for the

dition of

tion 4.8

imulator

lifetime

, and the

riod can

. It was

neutrons

2 shows

8/14/2019 978-1-61942-132-5_ch1

44/56

i

Ami4

The VI

quation 5

nterface, the

resentation

ther resourc

raphical inte

igure 13. Lin

igure 14. Log

r Zacarias M

HENEUT

amed Neu

resented in

user inserts

of the powe

s can also b

rfaces availa

ar channel.

arithmic chan

esquita, Ant

RONMU

tron Multipl

Section 4.8,

the initial p

may be in

simulated.

le for the u

el.

nio Juscelin

TIPLICA

ication, wh

was develo

ower and th

linear or lo

igures 13 a

er.

Pinto et al.

IONVI

ich was ins

ed. In the

period (T).

arithmic sc

d Figure 14

rted the

raphical

Graphic

ales, and

show the

8/14/2019 978-1-61942-132-5_ch1

45/56

l

On the

ariables con

1 TRIGA r

Thein th

is 0.

The100

The bloc

ther VIs of t

igure 15. Blo

In the VI

hich when

ogical seque

Neutron

THE

VI "Control

cerning the i

actor:

xcess of the

inhour equ

01s.

neutron ave

s or 0.0001s.

k diagram o

he program

k diagram of

"Control Pa

licked, pres

ce for using

c Parameter

ONTRO

Panel," th

nhour equati

multiplicati

tion. The d

age lifetim

the control

ere develop

he Control Pa

el" is also a

nts to the u

the simulato

to be Simul

PANEL

user must

on, which is

n factor D

fault value f

L [s], f

panel is sh

d block dia

nel.

vailable the

er the reco

r system.

ted

I

enter the

specific for

lta K, whic

or the IPR-R

r IPR-R1 T

wn in Fig.

rams similar

utton name

mendations,

35

ollowing

the IPR-

h is used

1 reactor

RIGA is

5. In all

to this.

"Help,"

tips and

8/14/2019 978-1-61942-132-5_ch1

46/56

Ami6

igure 2. Cont

The ope

Up" and "D

n the scre

SCRAM o

rogram scr

isualizes the

ig 17.

igure 3. Cont

r Zacarias M

ol panel user i

THE

ator perfor

wn" on the

n. There ar

for all rods

en where t

rod movem

ol rods front

esquita, Ant

nterface.

RODSC

s the contro

I Control

e buttons t

simultaneou

e operator

nt in a sche

anel.

nio Juscelin

NTROL

l rods mov

ods. The r

cause the

ly "Emerge

starts the r

e of the TR

Pinto et al.

I

ment using

ods position

scram of

cy." This is

actor opera

GA core as

the keys

is shown

ach rod

the main

tion and

shown in

8/14/2019 978-1-61942-132-5_ch1

47/56

Chapter 6

CONCLUSION

The IPR-R1 TRIGA nuclear reactor at Nuclear TechnologyDevelopment Center (CDTN) is used for education, particularly for the

needs of the Brazilian Nuclear Power Plants operators training. Thus, a

digital system was developed that simulates the behavior of the main

variables related to the routine startup of the reactor in order to assist in

the training conducted in this reactor. Students of physics and post-

graduate students of nuclear engineering can carry out practical exercises

on this reactor simulator system.

The variables derived from the neutron multiplication that can be

simulated are: the inhour curve (relationship between the reactivity and

the stable period T); the control rods worth; the neutron multiplication

(power). The control panel shows the reactor power in Linear and

Logarithmic Channels. With the simulator, several exercises can beperformed by simulating various operation scenarios, such as neutron

multiplication as a function of the rod position or as a function of a given

period.

The program can evaluate the effect of extreme values of several

variables, allowing understanding the process behavior and its

implications. This is of extreme importance for the safe operation of

nuclear reactors. The use of video screens for monitoring the operational

parameters is important in the normal operation and to perform basicoperator training. Advanced human-system interface technology is being

integrated into existing nuclear plants as part of plant modification and

upgrades.

8/14/2019 978-1-61942-132-5_ch1

48/56


The system simulator was developed using the LabVIEWsoftware

that is the most commonly program used for monitoring, control,

simulation and data acquisition. In LabVIEW

, the user builds an

interface, or front panel, with controls and indicators. The use of

customizable software and modular measurement hardware to create

user-defined measurement systems is called virtual instruments (VIs).

Their appearance and operation imitate physical instruments. The

resulting system has a user-friendly operator interface. Advanced human-

system interface technology is being integrated into existing nuclear

plants as part of plant modification and upgrades.A new version of the simulator is being developed to simulate the

entire power range of the IPR-R1 TRIGA reactor (until 250 kW). For this

upgrade a mathematical expression must be inserted that takes into

account the temperature coefficient of reactivity that occurs in operation

powers above about 1 kW.

8/14/2019 978-1-61942-132-5_ch1

49/56

ACKNOWLEDGMENTS

The authors express their thanks to the Research Support Foundation

of the State of Minas Gerais (FAPEMIG) and to the Brazilian Council for

Scientific and Technological Development (CNPq) for the financial

support.

8/14/2019 978-1-61942-132-5_ch1

50/56

8/14/2019 978-1-61942-132-5_ch1

51/56

REFERENCES

Bck, H., Villa, M. Physics and Kinetics of TRIGA Reactors. AIAU

24310. June 2004 (prepared for the IAEA under Contractual Service

Agreement Pers/JCH/nbb/ior/NSNI/Rev.1).

CDTN Centro de Desenvolvimento da Tecnologia Nuclear. Training

Course for Operators of Research Reactors- CTORP. 5 ed. 2 vol.,Belo Horizonte, MG. 1997. (in Portuguese).

Fadaei, A.H., Setayeshi, S. Control Rod Worth Calculation for VVER-

1000 Nuclear Reactor using WINS and CITATION Codes. Progress

Nuclear Energy, 2009, v.51, pp 184-191. Elsevier Ltd. Oxford UK.

General Atomics, TRIGA

Fuels. Available at http://www.ga-

esi.com/triga/products/fuel.php, accessed on 2010.12.14.

Glasstone, S.; Sesonske, A. Nuclear Reactor Engineering. 4 ed.

Chapman and Hall. New York, NY. 1994, pp 238-320.

Hoag, J.B.Nuclear Reactor Experiments. Argonne National Laboratory.Van Nostrand Co. Inc. Princeton, NJ, 1958, pp 203-214.

IAEA - International Atomic Energy Agency, Modern Instrumentation

and Control for Nuclear Power Plants: A Guidebook, IAEA,

Vienna, 1999. (Technical Reports Series No. 387).

IAEA - International Atomic Energy Agency. Modernization of

Instrumentation and Control in Nuclear Power Plants. Vienna:

IAEA, 1998. (IAEA-TECDOC-1016).

IAEA - International Atomic Energy Agency. Operational Limits andConditions and Operating Procedures for Research Reactors.

Vienna: IAEA, 2008. (Safety Guide No. NS-G-4.4).

8/14/2019 978-1-61942-132-5_ch1

52/56


Lamarsh, J.R.; Baratta, A.J. Introduction to Nuclear Engineering; 3 ed.

New Jersey: Prentice Hall: Upper Saddle River, NJ, 2001, pp 327-

376.

Mesquita, A.Z., Experimental Investigation on Temperatures

Distribuitions in a Research Nuclear Reactor TRIGA IPR-R1, Ph.D

thesis, Universidade Estadual de Campinas, So Paulo, Brazil. 2005.

(in Portuguese).

Mesquita, A.Z.; Souza, R.M.G.P. On-Line Monitoring of the IPR-R1

TRIGA Reactor Neutronic Parameters. Progress in Nuclear Energy

(New series), 2010, v. 52, pp 292-297. Elsevier Ltd. Oxford UK.National Instruments. Measurement and Automation - Graphical

Programming for Instrumentation. Austin: NI, 2007.

National Instruments. Virtual Instrumentation. Available at:

http://zone.ni.com/devzone/cda/tut/p/id/4752. Accessed on

2010.08.14.

Pederson, N. Building a Nuclear Reactor Control System Upgrade with

NI LabVIEW and Fieldpoint. Los Alamos: National Instruments,

2005.Pinto, A.J.Digital System for Simulation of Neutronic Parameters of the

IPR-R1 TRIGA Nuclear Research Reactor. Masters Thesis.

Postgraduate Program in Science and Technology of Radiation,

Minerals and Materials of the Nuclear Technology Development

Center. Belo Horizonte, MG. 2010. (in Portuguese).

Sitnikov, G. Computers for Reliable Nuclear Power Plant Control.

Conference reports, IAEA Bulletin, Vol.25, No.1, 1983.

8/14/2019 978-1-61942-132-5_ch1

53/56

8/14/2019 978-1-61942-132-5_ch1

54/56

Index44

Ffinancial, 39

financial support, 39

fission, vii, 2, 7, 10, 11, 13, 14, 15, 17,

18, 19, 28, 33

flexibility, 6, 26

fluid, 1

fragments, 20

G

gadolinium, 14

gas diffusion, 9

global warming, 1

graduate students, 37

graph, 21

graphite, 6

gravity, 29

greenhouse, 1

H

hafnium, 14

half-life, 17

health, 1

heat removal, 5

heat transfer, 1

height, 6host, 7

human, 25, 37, 38

I

icon, 25

industry, 5, 24

injury, iv

insertion, 13, 14, 31, 32interface, vii, 3, 23, 25, 32, 33, 34, 36,

37, 38

International Atomic Energy Agency,

vii, 9, 41

ionization, 28

IPR, vii, 1, 2, 5, 6, 7, 8, 14, 17, 20, 21,27, 31, 33, 35, 37, 38, 42

K

kinetics, 18, 19

L

leakage, 11, 17, 18

leaks, 12

lifetime, 18, 20, 33, 35

light, vii, 5, 7

M

magnitude, 29

man, 23

management, 23

mass, 10

matter, iv, 5

measurement, 7, 23, 24, 29, 38

medicine, 5

meter, 7, 28

methodology, 29

Microsoft, 26

multiplication, vii, 10, 11, 12, 13, 14, 20,

27, 28, 33, 35, 37

N

neutrons, 9, 10, 11, 12, 13, 14, 17, 18,

19, 28, 33

next generation, 11

nuclei, 10

nucleus, 17

O

operating system, 26

operations, 1, 2, 12, 28

8/14/2019 978-1-61942-132-5_ch1

55/56

Index 45

Ppermission, iv

permit, 6

photographs, 6

physics, 1, 37

plants, 25, 37, 38

population, 9

portability, 26

power plants, 23

preparation, ivprinciples, vii

programming, 25

protection, 12

R

Radiation, 42

reactivity, vii, 1, 12, 13, 14, 15, 18, 19,

20, 21, 27, 28, 29, 32, 33, 37, 38reality, 1

recommendations, iv, 35

redundancy, 1

reliability, 1, 2, 23, 25

renaissance, 1

requirements, 25, 26

resources, 34

rights, iv

rings, 7

risk, 23

risks, 23

rods, vii, 7, 13, 14, 15, 27, 28, 29, 30, 32,

36, 37

S

safety, vii, 1, 5, 7, 23

security, 1

sensors, 24services, iv

shape, 14

showing, 1

simulation, vii, 1, 2, 28, 38

software, vii, 2, 23, 24, 25, 26, 38

state, 5, 17, 28steel, 7

structure, 28

supplier, 5

sustainability, 1

T

techniques, 23

technologies, 26technology, 1, 24, 25, 37, 38

temperature, 1, 7, 13, 14, 15, 28, 38

testing, 2, 5

training, vii, 2, 5, 6, 9, 37

transmission, 2

transparency, 2

treatment, 5

tumors, 5

U

UK, 41, 42

uniform, 14

uranium, 6, 7

V

variables, viii, 15, 27, 32, 35, 37velocity, 10

versatility, 24

virtual instruments, vii, 24, 26, 29, 38

visualization, 2

W

water, vii, 5, 7

withdrawal, 14, 28workstation, 24

8/14/2019 978-1-61942-132-5_ch1

56/56

978-1-61942-132-5_ch1

Documents