Word: hre
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Dates: during 1960-1960
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Largely a brainchild of Dr. Weinberg, the reactor HRE-2 (for Homogeneous Reactor Experiment No. 2) is an attempt to avoid some of the worst disadvantages of solid-fuel reactors. Since solid uranium is quickly corroded at high temperature, it must be enclosed in a more resistant metal such as zirconium or stainless steel. As the uranium fissions, it generates gases that tend to burst the container. Other fission products absorb neutrons, and when too much of this "poison" has accumulated, it makes the nuclear reaction slow down or stop. At intervals, the fuel elements must be removed and their...
...HRE-2's fuel is uranyl sulphate dissolved in heavy water (which does not absorb as many neutrons as ordinary water). When this solution is flowing in a small-bore pipe, it does not react, because the fissionable uranium atoms are too strung out to form a critical mass. But when the fuel solution flows into a spherical reaction chamber, the compact mass becomes critical. A nuclear chain reaction starts, and heats the solution. Before the reaction goes too far, the solution is sucked away by pumps and forced through a heat exchanger, where it heats ordinary water...