Fast Reactor Database 2006 Update

Overview and Introduction

For almost 40 years, the IAEA has been serving interested Member States as a major fulcrum for fast reactor information exchange and collaborative research and technology development. Since 1967, the keystone of the Agency’s activities in this field is the Technical Working Group on Fast Reactors (TWG-FR, previously International Working Group on Fast Reactors, IWG-FR).

Thanks to the TWG-FR activities and to the support of the Agency’s INIS and Nuclear Knowledge Management Section, and based on the contributions of the TWG-FR Member States, it was possible to collect and assemble fast reactor design and operational data, as well as various other parameters, boundary conditions, and data related to operational experience, thus establishing a comprehensive overview of fast reactor technology. In particular, it is hoped that this reference document would permit reproducing, to a full or at least partial extent, the effective design approaches for fast reactor systems and components, and thus avoiding the repetition of unsuccessful design approaches.

The fast reactor database (FRDB) summarized in this report is very detailed1. It includes operational parameters, physical, hydraulic and thermomechanical characteristics, technological requirements, methods and criteria to ensure safe operation; design data like dimensions, materials information and main design features and performance parameters of reactor cores, components, and various systems, along with sketches and drawings.

Specifically, scientific and technological sections of the FRDB include the following information:

The FRDB is structured according to three reactor categories:

(i) experimental reactors, typically of up to 100 MW(th) built to demonstrate the technology, but often including a steam plant and turbine-generators to allow operation as a small power station;

(ii) demonstration or prototype reactors, in which much of the scaling up required for a commercial station in terms of both overall size and individual components has been incorporated;

(iii) commercial-sized reactors developed as prototypes to demonstrate the system's capability to operate in a utility environment.

The FRDB is arranged in units: records of parameters, characteristics and design features are arranged in columns on paired pages as follows: data on experimental, demonstration or prototype reactors (two units for 24 reactors) and on commercial size fast reactors (one unit for 13 reactors) on the first and the second page, respectively. This database setup makes it possible not only to easily find the required parameter of a certain reactor, but also to compare it with that of the other reactors.

The FRDB includes data on 37 fast reactor plants, their thermal power ranging from 10 to 4000 MW. Thirty-one reactors out of 37 are connected to steam turbine-generators of 12 to 1 800 MW electric power. These reactor designs have been developed during a 50-year period using a variety of design approaches, such as:

The FRDB includes also system related information, e.g., type and sensitivity of systems for SG leak detection, which is required for ensuring safe operation of the main components and of the power plant as a whole:

The FRDB reflects stages that have led to the physical and technological substantiation of fast reactor designs (from the first multi-purpose demonstration plant BN-350 to the EFR commercial power plant project). It comprises the numerous R&D findings that form the basis of fast reactor technology and design, of which the corner stones are:

The causes and conditions of general achievements and setbacks in reactor and liquid metal coolant technologies are presented in the FRDB, e.g. those determining breeding characteristics (core geometry, fuel enrichment and fissile isotope content, volume fractions, intrinsic limits and smeared density of fuel and blanket pellet, etc), and the fuel burnup limits (chemical composition, fuel fabrication technology, neutron flux, dimensions, cladding and wrapper material, etc.)

The FRDB summarizes ongoing activities by documenting operational parameters and designs aiming at simplification, increase of reliability and improved economics of SGs (as one of the most important components of the heat transport system). The SG design development is reflected in the FRDB from the prototype fast reactors for which a section and module design approach was adopted, with each SG section consisting of evaporator (ev), superheater (sh), and reheater (rh) modules. Accordingly, the three Phénix SGs include 36 sections and 108 modules, while the three BN-600 SGs have 24 sections and 72 modules. This concept assured minimum operating loss caused by leak incidents. As a rule, repair and maintenance procedures were required for only one module at a time. For instance, in order to restore a failed SG module of the BN-600 reactor, it was not necessary to shut-down the reactor but only to slightly decrease its power and isolate the failed SG section by valves. However, SG modular design is complicated, metal-intensive and in some cases less reliable. The design of sodium-heated SG has been largely changed during the development of fast reactor technology. Studies were aimed at the creation of a reliable, low-cost design, which is easily inspected (diagnosed) during operation (after a SG unit switch-off). Experience gained during development and operation has shown that neither micro modular (BOR-60, Phénix), nor macro modular (BN-600), nor double wall (EBR-II) SG met completely these criteria. Upon experimental confirmation of the long-term resistance of steels (such as mono-metallic modified 9Cr-lMo steel) in sodium, water and steam (including wet steam), a possibility of assurance of once-through process in the tube (water heating, boiling, evaporation, and steam superheating) has appeared. This result, along with sodium replacement with steam in the reheater, has made it possible to use a single-vessel SG, which was first applied to the Super-Phénix reactor, namely: 750 .W power unit having welded coil tubes (10 000 welds) operated reliably. A high self power steam generator of 600 .W with straight long tubes was then designed for the EFR power plant. It should be emphasized, that although designs and parameters of the early experimental fast reactors showed a wide variability, those of the commercial-sized plants are rather similar. Even with the initiation of a wholly new line of development, such as Pb and Pb-Bi cooled reactor designs, it is interesting to observe that their parameters are close to those of traditional reactors being advocated elsewhere. It is a further proof that the laws of physics and the principles of good engineering inevitably lead to similar optimal solution.

Summing up, the FRDB attempts to document the knowledge in fast reactor design and technology, as well as to preserve and to disseminate it until sustainability and economics criteria will create the necessary condition for large-scale deployment of fast reactors.

Last Updated:23-Apr-2007