On-site Refueling Research Articles

Functions of low-capacity nuclear power plants in supplying energy

The development of low-capacity nuclear power plants (LCNPs) in our country and the world is reviewed. Examples of designs which have been implemented are examined. Modern designs developed in our country and abroad are presented and analyzed. The requirements which LCNPs must satisfy without on-site refueling are formulated. The prospects for developing low-capacity nuclear power plants to provide energy and economic security in remote regions of our country are examined.

Small PWR Using Coated Particle Fuel of Thorium and Plutonium

An innovative concept of PFPWR50 for district heating has been studied, which is a small PWR of 50MWt capability using coated particle fuels with conventional zircaloy cladding. This concept takes advantages of fuel integrity against fission products release of coated particle fuels and a high reliability of PWR technology based on the long history of a successful operation. We have investigated burnup characteristics of fuel rods, assemblies, and reactor cores by the calculation code SRAC95 in order to establish a core concept of long life without on-site refueling. The loading pattern of assemblies with various concentrations of burnable poison is optimized to obtain a flat excess reactivity during the core life in order to eliminate a soluble boron control system. The core life of a cycle is about 8.9 equivalent full power years. And we have also studied the applicability of SiC/SiC composite cladding in place of zircaloy cladding, which is now under development for gas cooled fast reactor fuels. It could be applicable to high burnup fuel rods for a long term operation. From the calculation results, it is found out that the burnup characteristics do not change significantly with SiC cladding and contribute to elongate the core life to 9.2 equivalent full power years.

Iaea activities for innovative small and medium sized reactors (SMRs)

The renewed interest in many Member States in the development and application of Small and Medium Sized Reactors (SMRs) is reflected in the increased activities of the IAEA's (the Agency's) Nuclear Power Technology Development Section (NPTDS) for this trend. The paper gives an overview, summarizes intermediate result, and presents major findings of the NPTDS activities for innovative SMRs, including the preparation of new Status Report on Innovative SMR Designs, dedicated Report on Small Reactors without On-Site Refuelling and Coordinated Research Project for the Development of Small Reactors without On-Site Refuelling.

Seawater desalination using reusable type small PWR

Demand for seawater desalination is increasing, especially in regions such as the Middle East and North Africa, where populations are growing at a high annual rate. If such demand is met by fossil fuel energy, the influence on the environment, such as global warming, cannot be disregarded. Since these regions are behind in their preparedness of social capital infrastructure, such as power transfer grids, small reactors are considered to be more suitable for introduction than the large reactors found commonly in developed countries. Therefore, a small reusable PWR with mid-range pressure and temperature services, which does not require on-site refuelling, was devised for seawater desalination. In a small reusable PWR, spent fuel is taken out together with the reactor vessel and refuelled on the exterior fuel exchange base prepared independently. Thus, the safeguards against nuclear proliferation increase at a plant site because the lid of the reactor vessel is never opened at the site, in principle. The reactor vessel will be transported from the plant site to a fuel exchange base under stipulated conditions within a transportation cask after a long (about six years) operation. Since fuel handling facilities at the site become unnecessary through centralisation at a fuel exchange base, initial plant construction costs are reduced. In addition, the reactor vessel is reused until its service life has expired. This examination was based on the marine reactor of the experimental nuclear ship, Mutsu, after it had been applied for land use: at a lowered, midrange pressure and temperature service, in theory. It is possible to produce fresh water through reverse osmosis (RO) membrane pressure–rising seawater by a steam turbine driven pump. Using the method of driving a desalination unit high-pressure pump directly by low-pressure steam generated from the heating reactor, fresh water can be produced efficiently. Furthermore, operating at reduced pressure makes it possible not only to improve the transport performance of the reactor vessel but also to save plant construction costs, thus reducing bill materials of the primary system. There has been a worldwide trend for the RO method to be used for seawater desalination. So the reverse osmosis method was examined using low-pressure steam generated from a small heating reactor and compared with electrical power and evaporation methods (MED or MSF) utilising low-pressure steam towards a sea area with high salt concentration and countries that have been familiar with evaporation methods by fossil fuel energy.

The encapsulated nuclear heat source reactor for low-waste proliferation-resistant nuclear energy

The encapsulated nuclear heat source (ENHS) is a new Pb-Bi cooled modular reactor concept that features a combination of the following useful features that may make nuclear energy more attractive: (1) 20 years of full power operation without refueling. (2) Nearly constant fissile fuel contents and k eff. (3) No on-site refueling and fueling hardware. (4) The ENHS modules are factory manufactured and transported already fueled to the site. (5) No access to neutrons. (6) No mechanical connections between the ENHS module and the energy conversion plant (The ENHS module has the function of a nuclear battery — with 20 years of full power operation at 125 MW th). (7) At end of life, the ENHS module serves as a spent fuel storage cask and, later, as a spent fuel shipping cask. That is, the fuel is locked inside the ENHS from “cradle to grave”. (8) 100% natural circulation resulting in passive load following capability and autonomous control. This combination of features offers a highly safe nuclear energy system that is characterized by low waste, high proliferation resistance and high uranium utilization. The low waste and high uranium ore utilization are achieved by recycling the Pu and MA many times using a proliferation-resistant dry process; only fission products are to be extracted between cycles. Spent LWR fuel can provide for the HM make-up. The high level of proliferation resistance is obtained by restricting access to the fuel and neutrons and by eliminating the economic incentive of the client country to invest in sensitive technologies or infrastructure that can be used for clandestine production of strategic nuclear materials.

A concept of the multipurpose liquid metallic-fueled fast reactor system (MPFR)

Against fossil fuels, the nuclear energy is the only alternative energy source in the next century. Such energy source as the future nuclear power plant is expected to meet the following requirements. First, high temperature output for the multiple energy conversion capability as the electricity generation and the production of alternative fuels (hydrogen), which can be used widely in transportation systems. Second, the capability for siting close to the energy consumption area without onsite refueling. Third, the capability for nuclear fuel breeding and incineration of long-lived fission products, and fourth, the harmonization between active and passive safety features. This paper describes the basic concept of the Multipurpose liquid metallic-fueled Fast Reactor system (MPFR), which satisfies all mentioned requirements with introducing the U-Pu- x ( x: Mn, Fe, Co) liquid metallic alloys for the fuel. We can obtain such characteristics as high operational temperature of the reactor (between 550 °C and 1200 °C) and elongation of the core operational lifetime by the inherent fission product separation in the liquid fuel by using these alloys. The enhanced self-controllability is achieved by the thermal expansion of liquid fuel; and the re-criticality phenomenon at the core compaction events can be eliminated by discharging of the liquid fuel from the core.

Upgrading your heliport

During the past three years, there has been much discussion and action concerning the upgrading of aeromedical helicopters. The availability of new twins, more powerful singles, new avionics equipment and new litter configurations have given our rapidly growing industry much to consider. But heliports have remained basically the same. Or have they? During my first exposure to the hospital-based helicopter industry in 1979, very few, if any hospital heliports, had on-site refueling capabilities. Heliport lighting was heliport lighting nothing to change here. And IFR approaches to hospitals were out of the questions. Size? One hospital, one helicopter that's all there is to it. It soon became apparent, however, that the average aeromedical program was paying in excess of $30,000 annually in terms of rotor time and premium fuel rates to refuel at the local airport following the completion of each aeromedical flight. Innovations began to appear in heliport lighting and approach aids. And a number of hospitals found that they were missing too many missions because their single helicopter was always out 'on other flights.

On-site refueling

On-site refueling