Professor Oka's research team succeeded to develop the conceptual nuclear reactor design of high plutonium breeding by light water cooling for the first time in the world. He devised a new fuel assembly where fuel rods are closely packed for reducing reactor coolant to fuel volume fraction for high breeding.
With computational analysis he succeeded high plutonium breeding with light water cooling. The study will open the way of commercialization of fast reactor and nuclear fuel cycle for peaceful use of nuclear energy based on the mature light water cooling technologies. The result of the study was published in January issue of "Journal of Nuclear Science and Technology" of Atomic Energy Society of Japan (AESJ) , entitled "Plutonium breeding of light water cooled fast reactors".
Fast Breeder reactors (FBR) produce more fissile material than consuming, while producing electric power. It is a "dream of nuclear power". The main line of FBR development is the liquid metal cooled fast breeder reactor (LMFBR) . It is, however, not yet commercialized because of the complexity of the plant due to using liquid sodium as the coolant.
High plutonium breeding by light water cooling has been studied for many years, but not yet attained. Nuclear power plants and fossil fired power plant use water as the coolant. It is good to develop fast breeder reactor based on the experience of water coolant technologies.
Commercialization of nuclear fuel cycle and fast breeder reactors are important for reducing the amount of spent nuclear fuel of light water reactors (LWR) as well as the efficient utilization of uranium resources. Nuclear power utilization is in progress in many developing countries. Commercialization of spent nuclear fuel reprocessing in advanced countries enhances the nuclear security in the world.
High conversion light water reactors have been studied for many years since 1970 at research institutes and industry in Japan. The highest breeding characteristics were reported by the conceptual design study of the doubly axial heterogeneous core of a reduced moderation boiling water reactor (RMWR) . The compound system doubling time (CSDT) was, however, approximately 245 years. It is substantially longer than that of LMFBR.
Breeding characteristics increases with decreasing the water to fuel volume ratio. Tight fuel lattice with narrow gap between fuel rods was adopted for RMWR. For further decreasing the water to fuel volume fraction, a new fuel assembly of closely packed fuel rods was devised. The new fuel assembly and its fuel lattice consisting of three fuel rods are depicted in Fig.1. The coolant flows through the central hole of fuel lattice. The integrity or the leak tightness of the fuel rod is maintained as the conventional fuel rod where both ends of the fuel cladding tube are welded by end plugs.
The reactor design was carried out by computational methods for the cores with new fuel assemblies. The highest breeding characteristics are obtained for the core layout of the fuel assemblies in Fig. 2. The comparison of the characteristics with the RMWR is given in Table 1. The compound system doubling time is 43 years. It is substantially shorter than that of RMWR, 245 years.
Goal of breeding characteristics
The energy demand increases with the gross domestic product (GDP) . The growth rate of GDP of seven advanced countries of OECD is 1.4% per year in 10 years. With this growth rate, the GDP becomes double in 50 years and the energy demand does. The breeding characteristic of Table1 is 43 years, shorter than 50 years. It means that the fast breeder reactors with the new fuel assembly meet the goal of energy demand growth of advanced countries.
Future Research and Development items
Reactor design of boiling water reactor (BWR) condition, safety design and evaluation, development of the new fuel assembly including testing, demonstration with a prototype reactor.
High breeding with water cooling technology will open the way of commercializing nuclear fuel cycle and fast breeder reactors. It made it possible to reduce the amount of spent LWR fuels, to enhance the deployment and the security of peaceful uses of nuclear power in developing countries.
Compound system doubling time (CSDT) : Time required for system of identical breeder reactors to double the fissile material in the system, assuming that the number of reactors is increasing at a rate such that all of the fissile material is being utilized.
Light water: Water of natural composition of H2O and D2O. It is a technical term of nuclear technology in order to distinguish heavy water consisting of pure D2O
Yoshiaki Oka, Takashi Inoue and Taishi Yoshida, "Plutonium breeding of light water cooled fast reactors", J. Nuclear Science and Technology, vol.50 No.1, 15-20 (2013)
Grant in Aid for Scientific Research (B) o. 22360398, JSPS/ MEXT.
"Research and Development of Super Fast Reactor" entrusted to Waseda University by MEXT/ JST
Further Reports about: boiling water > computational method > developing countries > doubling time > End User Development > Nuclear > nuclear fuel > nuclear power > Plutonium > power plant > water cooling
More articles from Physics and Astronomy:
A Hidden Population of Exotic Neutron Stars
24.05.2013 | Chandra X-ray Center
Hubble reveals the Ring Nebula’s true shape
24.05.2013 | NASA/Goddard Space Flight Center
This morning at 05:45 CEST, the earth trembled beneath the Okhotsk Sea in the Pacific Northwest. The quake, with a magnitude of 8.2, took place at an exceptional depth of 605 kilometers.
Because of the great depth of the earthquake a tsunami is not expected and there should also be no major damage due to shaking.
Professor Frederik Tilmann of the GFZ German Research Centre for Geosciences: "The epicenter is exceptionally deep, far below the earth's crust in the mantle. Such strong ...
The Ring Nebula's distinctive shape makes it a popular illustration for astronomy books. But new observations by NASA's Hubble Space Telescope of the glowing gas shroud around an old, dying, sun-like star reveal a new twist.
"The nebula is not like a bagel, but rather, it's like a jelly doughnut, because it's filled with material in the middle," said C. Robert O'Dell of Vanderbilt University in Nashville, Tenn.
He leads a research team that used Hubble and several ground-based telescopes to obtain the best view yet of ...
New indicator molecules visualise the activation of auto-aggressive T cells in the body as never before
Biological processes are generally based on events at the molecular and cellular level. To understand what happens in the course of infections, diseases or normal bodily functions, scientists would need to examine individual cells and their activity directly in the tissue.
The development of new microscopes and fluorescent dyes in ...
A fried breakfast food popular in Spain provided the inspiration for the development of doughnut-shaped droplets that may provide scientists with a new approach for studying fundamental issues in physics, mathematics and materials.
The doughnut-shaped droplets, a shape known as toroidal, are formed from two dissimilar liquids using a simple rotating stage and an injection needle. About a millimeter in overall size, the droplets are produced individually, their shapes maintained by a surrounding springy material made of polymers.
Droplets in this toroidal shape made ...
Frauhofer FEP will present a novel roll-to-roll manufacturing process for high-barriers and functional films for flexible displays at the SID DisplayWeek 2013 in Vancouver – the International showcase for the Display Industry.
Displays that are flexible and paper thin at the same time?! What might still seem like science fiction will be a major topic at the SID Display Week 2013 that currently takes place in Vancouver in Canada.
High manufacturing cost and a short lifetime are still a major obstacle on ...
24.05.2013 | Life Sciences
24.05.2013 | Ecology, The Environment and Conservation
24.05.2013 | Physics and Astronomy
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News