Derevyannie Fermi Chertezhi3940891

Contents • • • • • • • • Fermi 1 [ ] The 69 MWe prototype Fermi 1 unit was under construction and development at the site from 1956 to 1963. Initial criticality was achieved on August 23, 1963. On October 5, 1966 Fermi 1. Two of the 92 fuel assemblies were partially damaged. According to the, there was no abnormal radioactivity released to the environment. Fermi 1 was a design. It was capable of producing 200 megawatts thermal (MWt) power or 69 MW electrical power with 26% enriched metallic uranium fuel.

このエントリーのトラックバックURL http://www.interline.or.jp/~k-z31/blog/mt-tb.cgi/1098.

The section of the reactor (core) was a 30 inch in diameter cylinder by 30 inches high and contained 92 fuel assemblies. The core was surrounded by 548 additional assemblies containing depleted uranium.

These assemblies were about 2.5 inches square by about 8 feet tall. Only the core section contained the enriched uranium while was placed above and below within the assemblies. The core also contained 2 control rods and 8 safety rods. The plant was designed for 430 MWt and 125 MWe using a newer uranium oxide fuel, but the plant was closed before the fuel was ever ordered. The shield plug was a rotating part of the inner reactor vessel and sat over the fuel. It could be rotated in order to facilitate fuel movements. The shield plug also provided radioactive shielding.

During fuel loading, new assemblies were lowered down a tube into an adjacent Transfer Rotor which was integral with the reactor vessel. Then an Offset Handling Mechanism lifted the assembly from the Transfer Rotor and placed it into the vessel.

Once all of the assemblies were loaded, a Hold Down Mechanism sat atop them so as to prevent them from moving upwards during operation. The Hold Down Mechanism also contained temperature measuring devices (resistance temperature detectors) to monitor sodium outlet temperatures from the assemblies. The (primary) sodium which flowed through the core exchanged heat with a secondary sodium system which then exited the containment. The secondary sodium then passed through the tube side of 3 parallel steam generators and transferred heat to water on the shell side. The “once through” design produced superheated steam which turned the main turbine-generator. A 168 oil-fired boiler was added in 1966 to utilize the turbine-generator during periods when the reactor was not producing power. The main cause of the partial meltdown was due to a temperature increase caused by a blockage in one of the lower support plate orifices that allowed the flow of liquid sodium into the reactor.

The blockage caused an insufficient amount of coolant to enter the fuel assembly; this was not noticed by the operators until the core temperature alarms sounded. Several fuel rod subassemblies reached high temperatures of around 700 °F (370 °C) (with an expected range near 580 °F, 304 °C), causing them to melt. Following an extended shutdown that involved fuel replacement, repairs to vessel, and cleanup, Fermi 1 restarted in July 1970 and reached full power. Due of lack of funds and aging equipment it was finally shut down permanently on November 27, 1972, and was officially December 31, 1975 under the definition of the. Later, the Nuclear Energy Commission replaced the AEC and under their new definitions, Fermi was re-designated as being in due to some remaining radioactivity at the site.