Experimental Breeder Reactor Ii Ebr Ii Shield Design

A description of the EBR-II shield and the methods employed in arriving at the final design are presented. The major shield design problems for that reactor are enumerated and discussed. (auth).

Koch, former manager of the Experimental Breeder Reactor-II (EBR-II), offers a first-hand account of the development, design, construction, and initial operation of this facility, which has contributed to the foundation of knowledge for all fast reactors. He explains why certain design choices were made while others were rejected. He also outlines how he thinks that future sodium cooled fast reactors should be designed, based on the experience gained with EBR-II. An appendix traces the lineage of EBR-II, including original memos and meeting notes, beginning with Enrico Fermi and Walter Zinn and progressing to the formation of the EBR-II project. B&w photos and illustrations are included. The book is of interest to designers of future fast reactors. There is no subject index.

A description of the EBR-II shield and the methods employed in arriving at the final design are presented. The major shield design problems for that reactor are enumerated and discussed.

The initial "Hazard Summary Report - Experimental Breeder Reactor-II (EBR-II)" was published as ANL-5719 in May, 1957. At the time of preparation of ANL-5719 (early 1957), the design of the EBR-II Facility was in progress - construction had not started. This Addendum is limited, for the most part, to changes which have been made in the EBR-II Facility, and to supporting experimental data developed, since the publication of ANL-5719.

The EBR-II reactor consists of an enriched core surrounded on all sides by a fertile blanket of depleted uranium. The fuel elements which comprise the core section of the reactor consist of small diameter cylindrical pin assemblies. The design of the fuel element is influenced by the desire for high thermal performance, high burnup, and simplicity of construction. The fuel pin is a loss fit in a thin-walled tube which provides a clearance annulus between the pin and the tube wall. This annulus is filled with static sodium to provide a heat transfer bond between the fuel and fuel tube. Heat is removed from the fuel element by the primary sodium flowing along the outside of the fuel tube.

The Experimental Breeder Reactor II (EBR-II) operated from 1964 to 1994. EBR-II was a sodium-cooled fast reactor operating at 69 MWth producing 19 MWe. Rather than using a loop approach for the coolant, EBR-II used a pool arrangement where the reactor core, primary coolant piping, and primary reactor coolant pumps were contained within the pool of sodium. Also contained within the pool was a heat exchanger where primary coolant, which is radioactive, transferred heat to secondary, nonradioactive, sodium. The nuclear power plant included a sodium boiler building where heat from the secondary sodium generated superheated steam, which was delivered to a turbine/generator for electricity production. EBR-II fuel was metallic uranium alloyed with various metals providing significant performance and safety enhancements over oxide fuel. The most significant EBR-II experiments occurred in April 1986. Relying on inherent physical properties of the reactor, two experiments were performed subjecting the reactor to loss of primary coolant flow without reactor SCRAM and loss of the secondary system heat removal without reactor SCRAM. In both experiments, the reactor experienced no damage. This chapter provides a description of the most important design features of EBR-II along with a summary of the landmark reactor safety experiments.

Experimental Breeder Reactor II (EBR-II) has operated for over 15 years at the Idaho National Engineering Laboratory near Idaho Falls. EBR-II has served the nation in providing information on fuels, materials, and components under conditions approaching those expected for commercial power plants. In addition, EBR-II is a power plant generating electricity with an availability of about 70%. A key component, the Intermediate Heat Exchanger (IHX), of any Liquid Metal Fast Breeder Reactor (LMFBR) must perform with a high degree of reliability for successful commercialization. The design and operating experience gained from EBR-II demonstrates that the IHX can be built and operated with confidence that its performance and reliability will be satisfactory.

EBR-II has operated for 25 years in support of several major programs. During this time period, several of the original, non-replaceable, flow sensors, RDT sensors and thermocouples have failed in the primary system. This has led to the development of new sensors and the use of calculated values using computer models of the plant. It is important for the next generation of LMR reactors to minimize or eliminate the use of non-replaceable sensors. EBR-II is perhaps the best modeled reactor in the world, thanks to a dedicated T-H analysis program. The success of this program relied on excellent measurements of temperature and flow in subassemblies in the core. The instrumented subassemblies of the XX series provided that measurement capability. From this test series, EBR-II calculations showed that the core could withstand a loss-of-flow without scram accident and a loss-of-heat sink without scram accident from full reactor power without core damage. From this, reactor designers can now design with confidence, inherently safe reactors. 11 refs., 8 figs.