Design and Stress Analysis of Extraterrestrial ... - The Black Vault

esistance in
prolonged operation.
the channels, as well as high reliability during;
Operational reliability is achieved by an absolute seal
to prevent, the mixing of the heat transfer agents in the
first and second loops. This is connected with the induced y-
activity acquired by the heat carrier of the first loop in transit
through the reactor as a result of the action of neatron flows.
Furthermore, with a breakdown in the coating density of the nuclear
reactor fuel elements, the heat carrier of the first loop can be
4 loaded by nuclear fuel fision fragments.
Through the active reactor core, along with the heat carrier,
pass the products of the corrosion and erosion of the structural
elements of the first loop. The radioactive isotopes formed in this
case can settle on the walls of the piping and the heat exchanger,
raising the radioactivity of the loop (to control this phenomenon
in
the first loop a special purification system for the heat transfer
agent is
usually provided).
Strict requirements for the seal of heat exchange equipment
are also dictated by the danger of the contamination of the heat
carrier in the first loop by foreign matter from the power loop,
which can cause a breakdown in
reactor operation.
To provide a seal for the heat exchange equipment during prolonged
operation it iZ recommended to weld all connections. Seal is ensured
by the selection of appropriate manufacturing procedures and quality
inspection methods (operational control) for the welded Joints. To
check the seal vacuum tests are made on the item as a whole and
the welds are inspected with a helium leak detector or by other
means.
Most frequently damage appears at the location of welds on
pipes as a result of thermal stress occurring during operation.
Therefore, in addition to quality welding technique, it is nece3sary
to provide structural measures reducing these stresses to a minirnui
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