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General principles for public involvement
Published in Gianluca Ferraro, The Politics of Radioactive Waste Management, 2018
The peaceful use of nuclear energy in the European Union (EU) is governed by the Euratom Treaty which established the European Atomic Energy Community (Euratom) in 1957 (chapter 1). The Euratom Community is a separate legal entity from the EU, but is governed by the same institutions. In the framework of Euratom, the European Commission (EC) deals with nuclear activities with a focus on three major aspects: nuclear safety, nuclear security and nuclear safeguards. Nuclear safety is about the safe operation of nuclear installations and is complemented by radiation protection and radioactive waste management (RWM). Nuclear security relates to the physical protection of nuclear material and installations against intentional malicious acts (e.g., sabotage and theft). Nuclear safeguards are measures to ensure that nuclear materials are used only for the peaceful purposes declared by the users.1
Heat Transfer, Thermal Hydraulic, and Safety Analysis
Published in Kenneth D. Kok, Nuclear Engineering Handbook, 2016
In addition to the barriers and protection layers, the reactor is also designed with safety system. The three primary objectives of nuclear safety systems are (1) shut down the reactor, (2) maintain it in a shutdown condition, and (3) prevent the release of radioactive material during events and accidents. These objectives are accomplished using a variety of equipment, which are part of different systems, of which each performs specific functions. The safety systems are provided for each NPP and are explained below.
Safety Analysis in VVER-1000 Due to Large-Break Loss-of-Coolant Accident and Station Blackout Transient Using RELAP5/SCDAPSIM/MOD3.5
Published in Nuclear Science and Engineering, 2022
Fabiano Gibson Daud Thulu, Ayah Elshahat, Mohamed Hassan
Nuclear safety is defined by the International Atomic Energy Agency (IAEA) as “The achievement of proper operating conditions, prevention of accidents or mitigation of accident consequences, resulting in protection of workers, public and environment from undue radiation hazards.1 Reactor safety analysis helps to improve the environmental indicators used to evaluate the overall sustainability of the nuclear energy industry.2 Accidents that lead to a severely damaged reactor core are termed “severe.” Examples are station blackout (SBO) due to total loss of off-site power (LOOP) and large-break loss-of-coolant accident (LB-LOCA) without the availability of emergency core cooling systems3 (ECCSs). Initiating events to total core damage frequency (CDF) of VVER-1000 are presented in Fig. 1. It shows that the SBO accident is a dominant contributor to the total CDF (having a share of 26%). Loss of all alternating-current (AC) power sources is deemed as the failure of all normal operation power supply systems and diesel generators of the emergency power supply system.4 The SBO is easily identified due to loss of all normal and emergency operating systems with the exception of the direct-current (DC) system.5 Severe accident mitigation guidelines and emergency response are always needed to contain radioactive release in such accidents.
Analysis and Simulation of a Gripper for Fuel Handling on China Lead-Based Research Reactor
Published in Nuclear Technology, 2018
Meihua Zeng, Yong Song, Yunqing Bai, Minghuang Wang, Meisheng He, Jie Yu
The configuration of the primary system of CLEAR-I is compact and pool type. Nuclear safety is considered as the top priority in nuclear energy development, particularly after the Chernobyl and Fukushima nuclear accidents.17 The configuration adopts an in-vessel remote handling refueling system in CLEAR-I. The gripper is required to complete the assembly loading and unloading operational tasks in the vessel in a high-temperature and liquid heavy-metal environment.18,19 The spallation target is located at the center of the reactor core and it is attached to the end of the accelerator proton beam tube.20 The tube runs through the pile cap into the core, which blocks the movement of the refueling machine, and it cannot be removed when the refueling is being carried out in the closed state of the reactor cap. The LBE will bring significant influence of high temperature, corrosion, and buoyancy to the gripper. Meanwhile, the fuel assembly (FA) chosen uses metal-depleted uranium as ballast to overcome the buoyancy for the high density of the LBE and adopts an internal-type operating head, just as used in pressurized water reactors21,22 (PWRs). The weight of the FA becomes larger. It requires a gripper that is also an internal type and that has sufficient bearing capacity. Due to high temperature and the opaqueness of the coolant, cameras, laser sensors, or electromagnetic waves cannot be used to provide visual and positional feedback to the gripper.23 The above characteristics bring a great challenge to the design of the refueling system and gripper for CLEAR-I.
From “Inherently Safe” to “Proliferation Resistant”: New Perspectives on Reactor Designs
Published in Nuclear Technology, 2021
The emphasis on safety, and eventually “inherent safety,” emerged only gradually as it became clear that accidents were possible, some with significant consequences.26 In terms of design, this idea manifested itself in modifications of existing reactor types, not in entirely new designs. For example, engineers in the USSR kept upgrading the RBMK design, resulting in a series of RBMK “generations” that each featured safety improvements.7 Similarly, in the United States designers didn’t fundamentally alter their reactor lines, even though they continuously improved them based on experience with already operating units.27,gVery specific definitions of “inherent safety” were developed much later.28 The conversation about new reactor designs today revolves very much around the topic of safety, as sophisticated licensing, regulatory, and inspection regimes have evolved, albeit for only a few types of reactors.hIn addition to the U.S. Nuclear Regulatory Commission (NRC), such regulatory infrastructures include Ukraine’s State Nuclear Regulatory Inspectorate, Russia’s Rostechnadzor (which combines nuclear with environmental and industrial regulation), and European Union organizations such as the Western European Nuclear Regulators’ Association (WENRA) and the European Nuclear Safety Regulators Group (ENSREG) that coordinate European regulators, along with guidelines developed by the International Atomic Energy Agency (IAEA) (see, e.g., https://www.iaea.org/topics/regulatory-infrastructure and http://www.ensreg.eu/members-glance/national-regulators. Designs that don’t fit into any of these regimes face additional challenges because the rules of what constitutes safety aren’t yet established for them. This has led designers to shy away from truly revolutionary innovation, relying instead on both a proven safety record of certain features and materials and innovating within the frameworks that were developed for existing designs.10