One second shutdown system is proposed for the Tehran Research Reactor to
achieve the goal of higher safety in compliance with current operational
requirements and regulations and improve the overall reliability of the
reactor shutdown system. The proposed second shutdown system is a diverse,
independent shutdown system compared to the existing rod based one that
intends to achieve and maintain sub-criticality condition with an enough
shutdown margin in many of abnormal situations. It is designed as much as
practical based on neutron absorber solution injection into the existing core
while the changes and interferences with the existing core structure are kept
to a minimum. Core neutronic calculations were performed using MCNPX 2.6.0
and MTR_PC package for the current operational core equipped with the second
shutdown system, and one experiment was conducted in the Tehran Research
Reactor to test the neutronic calculations. A good agreement was seen between
theoretical results and experimental ones. In addition, capability of the
second shutdown system in the case of occurrence of design basis accident in
the Tehran Research Reactor is demonstrated using PARET program.
Oak Ridge Research Reactor shutdown maintenance and surveillance
