Principles Sodium Reactor Experiment

cutaway view of sre reactor; rotatable shield 6 feet (1.8 m) thick (jarett, pg. ii-a-2)

the purpose of sodium reactor experiment demonstrate feasibility of sodium-cooled reactor heat source commercial power reactor produce electricity. secondary objective obtain operational data on enriched fuel , uranium-thorium fuel mixtures. reactor designed flexible development facility, , considered development tool emphasizing investigation of fuel materials.

compared water (or steam), sodium has relatively low vapor pressure @ operating temperatures of reactor. sodium reactor experiment design utilized sodium coolant high-pressure water systems not required. reactor did not have containment pressure vessel, because maximum credible accident not release enough gas volume require pressure containment. designed retain gases @ atmospheric pressure , reduce diffusion leakage potentially contaminated gas.

the sodium reactor experiment included complex of buildings, workshops , support systems. reactor housed in main reactor building, consisted of high bay area , hot cell facility. 3 cleaning cells located in main building. cleaning cells designed wash sodium fuel elements water in inert atmosphere. cleaning allowed examination of fuel rods after removed reactor. because sodium reacts violently water, wash cell sealed off , flooded inert gas minimize reaction during washing. operators worked behind thick walls limit exposure radiation emitted fuel elements, loaded cell through ceiling entrance hole (normally covered heavy shield plug).

fuel element sre reactor, 1957–1959; narrow clearance between fuel elements in center (jarett, pg. ii-a-6)

the reactor core sat in lower portion of vessel lined stainless steel , filled liquid sodium. sodium reactor experiment reactor core contained forty-three fuel elements, each comprising 7 fuel rods. fuel rod stainless steel tube 6 feet long, filled twelve uranium fuel slugs. many of fuel elements in sre instrumented thermocouples located in center of fuel materials @ several places in core. 2 of thermocouples monitored in reactor control room, while remaining measurements recorded on instrumentation outside control room. sodium temperature monitored @ several points within reactor system.

at full power, sodium @ temperature of approximately 500 °f (260 °c) passed through plenum chamber beneath reactor core through heat channels absorbing heat released fuel elements, , discharged upper pool (about 6 feet (1.8 m) deep) above core @ average temperature of 950 °f (510 °c). space filled helium gas, maintained @ pressure of approximately 3 pounds per square inch. piping circulated 50,000 pounds (22,680 kg) of heated liquid sodium reactor vessel 1 of 2 available heat exchangers. 1 heat exchanger transferred heat primary sodium loop, in turn dissipated heat in steam generator boiled water make steam use in turbine generating electricity.

the gases used cover gas in sodium systems (such reactor , fuel-assembly wash cells) potentially radioactive. design of sodium reactor experiment support facilities collect such gases tank, compress them , put them gas holding tank until had decayed sufficiently allow discharge environment outdoor stack.