Focusing on Both Nuclear Energy and Radiation Application for Constructing an Eco-Friendly and Healthy Society

●Nuclear Energy Research is the Bridge to Future Energy Development

To resist global warming, humankind must find new sources of energy to replace fossil fuels. At present, the production of hydrogen from renewable energy sources and the nuclear fusion are expected to be the most promising future energies. However, hydrogen is not a primary energy source and nuclear fusion may need additional 50 to 60 years to become a practical energy option. Nowadays, the nuclear fission energy holds an inevitable role during the period of transition from the major use of fossil energies to the hydrogen-based renewable energy and the nuclear fusion energy in the future. Therefore, the use and development of nuclear-fission power generation is currently a necessity to the world and remains an important energy source in advanced countries.

The Nuclear power generation represents an integration of four fundamental disciplines of engineering: neutron physics, thermal hydraulic, materials, and instrumentation & control.

The Institute of Nuclear Engineering and Science at the National Tsing Hua University (NTHU) offers comprehensive courses of nuclear power and solid trainings to our students. Many of our alumni are working in the Taiwan power company, the Atomic Energy Council, and the Institute of Nuclear Energy Research. They can be outstanding researchers that serve in national Laboratories, medical centers, foreign nuclear companies, academic and research institutions, and many fields of modern technologies. Cultivating successors and future faculty members of nuclear engineering is also one of the major objectives of our Institute.

• Nuclear Power Plant Engineering: Aiming at Research on Nuclear Safety

Many advanced countries are actively developing new nuclear power generation technologies. Taiwan must keep up with these developments to ensure the efficiency and safety of nuclear power plants. Nuclear power plant engineering is one of the major research topics of our Institute. All research results can be applied to improve the efficiency and safety of the existing and future nuclear reactors. Over the past few years, the fuel loading pattern design is the major research objective of our Institute; in this way, the increase of reactor power and/or the reduction of operation cost can be accomplished by optimizing the arrangement of the fuel rods and control rods in the core. By assigning a loading pattern that elucidates the variation of enrichment of the fuel rods distributed in the reactor core, an improved uniformity of the fuel burnup in the core can be realized; as a result, a satisfactory power shape flattening can be achieved for a reactor which ultimately benefits the efficiency and safety of a nuclear power plant. During the design of loading pattern, one has to prevent possible damages happened to the fuel rods and the radiation-releasing damage to the plant. Therefore, this is a subject that requires professional knowledge under the discipline of nuclear engineering.

Nuclear power systems are designed on the basis of detailed thermal and hydraulic analyses, so that the thermal energy produced from the fuel can be efficiently transferred to the coolant and subsequently used for generating electricity. In order to improve the safety of nuclear power plants, the faculty members of thermal hydraulics group develop sophisticated programs to analyze the fluid dynamics and the heat transfer phenomena in a reactor system. They also develop the safety analysis code associated with the rector control and power generation systems. Many kinds of accidents, such as the anticipated and abnormal plant transients, the loss of coolant accident, and the station blackout, have to be analyzed when designing a nuclear power plant. It is essential to understand how the parameters relating to the system statues change in every accidental situation, so that a safe and successful operation of a nuclear power plant can be achieved accordingly. In conjunction with the thermal hydraulic safety analysis of the system, the CFD codes are used to comprehensively analyze the complicated fluid flow and multiphase heat transfer phenomena, which gives the detailed distribution of temperature, pressure, and velocity inside a reactor.

Moreover, the research on material science is crucial to nuclear engineering as well. In long-term operation, the presence of intense radiation and high temperature can cause the corrosion, erosion, and aging to the components employed in a nuclear reactor. Therefore, the use of advanced materials for making the reactor components is essential to support the normal operation of nuclear power plants.

• Research on Next-Generation Nuclear Reactors: Moving on Sustainable Energy and Environment

Our Institute will continue the research of next-generation reactors and focus on realizing the energy and environmental sustainability in the future. The research of high temperature gas-cooled reactor aims at producing hydrogen and electricity. In parallel, the research of molten-salt reactor (MSR) seeks feasible solutions to process the long-lived radioactive elements (fission products) contained in the high-level spent fuel. These long-lived radionuclides can transmute to elements of much shorter half-lives by feeding spent fuels into a MSR; in this way, the primary concern about the high level radioactive waste final disposal can be resolved in a simpler and safer manner.

Another future research direction is associated with the small modular reactors (SMRs). Although SMRs produce a lower amount of electricity than the current light-water reactors, they provide advantages on the improved safety and the reduced complexity of site selection. A SMR can be constructed on the outskirt of a city and provides sufficient, economical, safe, stable, sustainable and environmentally-friendly electricity to support the life of inhabitants therein. The high potential of SMRs makes it worth great investments to continue their future developments. Meanwhile, the development of liquid metal fast breeder reactors (LMFBRs) has made a brilliant achievement in the field of GEN-IV reactor research. With the advantages of energy and environmental sustainability, the LMFBR is considered as a rapidly maturing technology to demonstrate the construction of a GEN-IV nuclear power plant.

• Decommissioning and Disposal of Spent Fuel: Managing and Being Responsible for Engineering Lifecycle Management

The storage of spent fuel is also a significant part of nuclear power management. Currently, the method of dry storage has been implemented in Taiwan to achieve the interim storage of spent fuel. This strategy helps to solve the problems of overloaded spent fuel pool in the plants and enhance the storage safety. Relevant key techniques include the characterization of nuclear spent fuel, criticality safety estimation, heat transfer calculation, and radiation shielding. These techniques can also be applied to accomplish the preparation and evaluation of the process of decommissioning a nuclear power plant. In Taiwan, a decommissioning plan has to be proposed to the Atomic Energy Council (AEC) at least three years prior to the scheduled permanent shutdown. As the AEC grants the permission, the decommissioning has to be completed within the next 25 years. In addition to the existing six reactor units in Taiwan, the considerable quantities of second generation nuclear power plants established around the world will account for a great demand of decommission in the future. Therefore, the development of decommissioning techniques in Taiwan is necessary and can be a promising direction to produce huge profits for the associated industries.

●Various Radiation Applications Aim at Improving the Quality of Life

Radiation is closely related to human society. Natural radioactivity can be found in the environments all around us, such as these contained in the air, soil, buildings, water, and food. Our faculty members conduct extensive studies for understanding the characterizations of natural radiation, which contributes to the clarification of public’s misunderstanding of radiation risks. The applications of radiation have brought numerous benefits to us, including the nuclear power generation, medical diagnosis and treatments, airport inspection, non-destructive testing in industry, sterilization of agricultural products, archeology, and mining. Radiation and its related imaging and/or spectroscopic technologies also play essential roles in cutting-edge scientific research. The Tsing Hua Open-Pool Reactor (THOR), located in the campus of NTHU, is dedicated to be a cradle in Taiwan for nurturing our future scientists and engineers in nuclear engineering and radiation applications. The research on boron neutron capture therapy (BNCT) conducted in our institute is a successful example. In addition to developing a variety of applications with artificial radiation sources, our Institute focuses on education of radiation safety and radiation shielding techniques. Because of the wide use of radiation in science and technology, our alumni’s career directions can be extended to the fields of nuclear power generation, medicine, industry, agriculture, archeology, and geology.

• Boron Neutron Capture Therapy (BNCT): Opening a New Page to Targeted Heavy Particle Therapy

In the field of radiation applications, BNCT is the ongoing focus of our Institute. BNCT can accurately destroy tumor cells, reduce the chance of tumor recurrence, and alleviate side effects that may happen on normal tissues. At NTHU, BNCT has been employed to treat recurrent cancers that can be challenging if treated by other conventional methods of therapies.

In the process of BNCT treatment, the patient will first take the injection of a boron-containing drug which can selectively accumulate in cancer cells or malign tumors. Next, an epithermal neutron beam is introduced to irradiate the tumor region. As the epithermal neutrons enter the body and decelerate into thermal neutrons, many of them interact with the B-10 nuclei contained in the tumor cells and induce associated nuclear fissions that yield α and Li-7 particles. Because α and Li-7 possess the high linear energy transfer characteristics, they can rapidly deposit all of their energies over a very short distance inside a tumor cell and consequently cause a deep damage to the DNA of this tumor cell. Therefore, a targeted tumor cell can be effectively destroyed by an induced neutron capture reaction. In contrast, the normal tissues can experience a limited radiation injury throughout the BNCT, as this is attributed by the low boron concentration existing in normal regions and the little biological effect that the decelerated thermal neutrons can act on human body. BNCT combines the specialties of targeted cancer therapy and radiotherapy.

The achievement of BNCT requires close collaborations supported by specialists coming from a variety of backgrounds. A number of faculty members and students of our Institute have devoted themselves into the BNCT research and use THOR to conduct BNCT clinical trials of cancer treatment. The high-quality epithermal neutron beams suitable for BNCT were constructed in 2004. Meanwhile, preclinical studies associated with the measurement of intensity and energy spectrum of neutron beam, the program of treatment planning, the boron-containing drugs, and the pharmacokinetic have been actively carried on over the years. We also collaborate with the Taipei Veterans General Hospital and the Kyoto University to implement the clinical treatments. The first BNCT clinical trial using the THOR at NTHU is carried out on August 11^th, 2010. During the first phase of clinical trials (completed in 2014), a total of 17 patients, having recurrent head and neck cancers that could be incurable by conventional therapies, was treated by BNCT (each patient received only two BNCT irradiation). Significantly improved condition and quality of life are achieved for the 17 patients. More importantly, 6 of them were declared as complete response to the tumor at the end. BNCT presents a promising and advanced treatment technology for the cancer patients.

• Medical Physics: Controlling the Quality of Medical Imaging and Radiotherapy

Medical use of radiation is very important in the field of radiation applications. As radiation is a probe to explore the structural and metabolic information of the human body, it brings medical imaging to help radiologists carry out diagnoses of patients. When radiation is used in a radiation therapy, the radiation beams are accurately aligned with a tumor, and then kill tumor cells with a larger dose while the damages are minimized to normal tissues. Medical physics is the physics applied in medicine and generally divided into two major fields: medical imaging and radiation therapy. These two applications require the participations of specialists with a profound knowledge of the interactions of radiation with matter.

To ensure the accuracy and optimization of medical use of radiation, the medical physicists are dedicated to develop specifications for imaging and therapy equipment, diagnostic radiation detectors, radiation therapy treatment, brachytherapy, simulation, and radiation measurement; to develop procedures for the initial and continuing evaluation of medical facilities; to provide evidence of compliance of imaging and therapy equipment with regulatory and accreditation agency rules and recommendations; to develop and evaluate of policies and procedures related to the appropriate clinical use of radiation for imaging/therapy purposes; to develop and manage of a comprehensive quality management program that monitors, evaluates, and optimizes imaging processes and treatment planning; to consult in the development and/or evaluation of a comprehensive clinical radiation safety program, to assure an optimized balance between image quality and patient dose; to review dosimetry information noted in patient records and consult on patient or personnel radiation dose and associated risks; to provide medical physics training for medical practitioners and other health-care providers.

The BNCT project conduced in our Institute is a multidisciplinary integration of the knowledge of medical imaging, nuclear medicine, and radiation therapy. Students involved in this research project will gain extensive experiences relating to computed tomography, positron emission tomography, and reactor-based neutron irradiation facilities. Our Institute also provides students solid courses and research opportunities in the fields of medical physics and biomedicine, which enables our students to team up with radiologists, oncologists, and technologists for improving radiation therapies.

• Beam Science: an Essential Foundation for Advancing Scientific Research

The research topics of beam science are developed on the basis of the interaction of X-rays, neutrons, high-energy electrons, and heavy charged particles with matters. By analyzing the scattered patterns, energy spectra of photons and charged particles, or images, the structural characteristic of a matter and the components contained in a material can be understood in details. Several faculty members of our Institute are specialized in the techniques of small angle scattering of X-rays and neutrons, which are utilized to explore the properties of soft matter and biomedical materials. They also cooperate with the National Synchrotron Radiation Center to carry out the research on energy materials, magnetic thin-film, and semiconductor structures by using the developed techniques of X-ray scattering spectrum and X-ray absorption spectrum. Regarding the development of novel radiation sources, a new trend of research is to apply femtosecond (fs, 10^-15s) laser pulses to drive a compact electron accelerator and produce keV coherent X-ray. Related applications include the developments of advanced X-ray diffraction microscopy and X-ray phase-contrast imaging capable of resolving nanostructures and biostructures, respectively. These techniques will subsequently contribute to the progress of associated physics, materials and biomedical detection technologies.