Preface

Rising concerns about global warming, supply security, and depleting fossil fuel reserves have spurred a revival of interest in nuclear power generation, 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 is a proven technology and has the potential to generate virtually limitless energy with no greenhouse gas emissions during operations. According to the International Atomic Energy Agency the number of nuclear power reactors in operation worldwide in 2011 is 433 units, and 65 under construction. A large-scale period of nuclear power plants construction would allow nuclear energy to contribute substantially to the decarbonisation of electricity generation. 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.

The renaissance of nuclear power has been threatened by the catastrophe in Japan and the atomic industry faces the challenge of assuring a skeptical public that new reactors are safer than the old ones and nearly disaster-proof. The disaster at the Fukushima Daiichi nuclear plant in Japan demonstrates that older nuclear reactor technology requires strict adherence to quality assurance practices and procedures. Newer nuclear reactor designs promote the use of passive cooling systems that would not fail after power outages, as well as other innovative approaches to managing reactor heat. New reactors use the same principle of power generation as in older water reactors such as the ones at Fukushima: nuclear reactors heat water to create steam that turns turbines to generate electricity. However, technological advances have improved efficiency and stricter safety precautions have made the third-generation reactors more secure. The new generation of pressurized water reactor plants has diesel-powered backup systems that are housed in separate buildings to protect them from any accident that might occur in the main reactor building. The plant must also have access to other sources of electricity if the diesel generators fail.

This book is targeted at nuclear regulatory authorities, environmental and energy scientists, students, researchers, engineers, seismologists and consultants. It presents a comprehensive review of studies in nuclear reactors technology from authors across

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the globe. Topics discussed in this compilation include: thermal hydraulic investigation of TRIGA type research reactor, materials testing reactor and high temperature gas-cooled reactor; the use of radiogenic lead recovered from ores as a coolant for fast reactors; decay heat in reactors and spent-fuel pools; present status of two-phase flow studies in reactor components; thermal aspects of conventional and alternative fuels in supercritical water‒cooled reactor; two-phase flow coolant behavior in boiling water reactors under earthquake condition; simulation of nuclear reactors core; fuel life control in light-water reactors; methods for monitoring and controlling power in nuclear reactors; structural materials modeling for the next generation of nuclear reactors; application of the results of finite group theory in reactor physics; and the usability of vermiculite as a shield for nuclear reactor. Concluding the book is presented a review of the use of neutron flux in the radioisotopes production for medicine.

> **Amir Zacarias Mesquita, ScD**. Researcher of Nuclear Technology Development Center (CDTN) Brazilian Nuclear Energy Commission (CNEN) Belo Horizonte - Brazil

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radioisotopes production for medicine.

the globe. Topics discussed in this compilation include: thermal hydraulic investigation of TRIGA type research reactor, materials testing reactor and high temperature gas-cooled reactor; the use of radiogenic lead recovered from ores as a coolant for fast reactors; decay heat in reactors and spent-fuel pools; present status of two-phase flow studies in reactor components; thermal aspects of conventional and alternative fuels in supercritical water‒cooled reactor; two-phase flow coolant behavior in boiling water reactors under earthquake condition; simulation of nuclear reactors core; fuel life control in light-water reactors; methods for monitoring and controlling power in nuclear reactors; structural materials modeling for the next generation of nuclear reactors; application of the results of finite group theory in reactor physics; and the usability of vermiculite as a shield for nuclear reactor. Concluding the book is presented a review of the use of neutron flux in the

**Amir Zacarias Mesquita, ScD**.

Belo Horizonte - Brazil

Nuclear Technology Development Center (CDTN) Brazilian Nuclear Energy Commission (CNEN)

Researcher of

**1** 

*Brazil* 

**Experimental Investigation of** 

Amir Zacarias Mesquita1, Daniel Artur P. Palma2, Antonella Lombardi Costa3, Cláubia Pereira3,

Maria Auxiliadora F. Veloso3 and Patrícia Amélia L. Reis3

*3Departamento de Engenharia Nuclear –Universidade Federal de Minas Gerais* 

*1Centro de Desenvolvimento da Tecnologia Nuclear/Comissão Nacional de Energia Nuclear* 

Rising concerns about global warming and energy security have spurred a revival of interest in nuclear energy, leading to a "nuclear power renaissance" in countries the world over. In Brazil, the nuclear renaissance can be seen in the completion of construction of its third nuclear power plant and in the government's decision to design and build the Brazilian Multipurpose research Reactor (RMB). The role of nuclear energy in Brazil is complementary to others sources. Presently two Nuclear Power Plants are in operation (Angra 1 and 2) with a total of 2000 MWe that accounts for the generation of approximately 3% of electric power consumed in Brazil. A third unity (Angra 3) is under construction. Even though with such relatively small nuclear park, Brazil has one of the biggest world nuclear resources, being the sixth natural uranium resource in the world and has a fuel cycle industry capable to provide fuel elements. Brazil has four research reactors in operation: the MB-01, a 0.1 kW critical facility; the IEA-R1, a 5 MW pool type reactor; the Argonauta, a 500 W Argonaut type reactor and the IPR-R1, a 100 kW TRIGA Mark I type reactor. They were constructed mainly for using in education, radioisotope production and nuclear research. Understanding the behavior of the operational parameters of nuclear reactors allow the development of improved analytical models to predict the fuel temperature, and contributing to their safety. The recent natural disaster that caused damage in four reactors at the Fukushima nuclear power plant shows the importance of studies and experiments on natural convection to remove heat from the residual remaining after the shutdown. Experiments, developments and innovations used for research reactors can be later applied to larger power reactors. Their relatively low cost allows research reactors to provide an

The IPR-R1 TRIGA Mark-I research reactor is located at the Nuclear Technology Development Centre - CDTN (Belo Horizonte/Brazil*)*, a research institute of the Brazilian Nuclear Energy Commission - CNEN. The IPR-R1 reached its first criticality on November

**1. Introduction** 

excellent testing ground for the reactors of tomorrow.

**Nuclear Reactor** 

*2Comissão Nacional de Energia Nuclear* 

**Thermal Hydraulics in the IPR-R1 TRIGA** 
