Anti-Criticality Methods for Nuclear Thermal Rocket Launches and Their Associated Assembly / Disassembly in Space

When launching a nuclear reactor into space for use in a nuclear thermal rocket (NTR), safety to the public is of the outmost importance. Ensuring that the reactor will not go critical in an accident scenario is the biggest risk that must be overcome to protect the public. Use of anti-criticality devices and methods, such as the use of poison materials in the core or loading a select portion of the fuel on orbit, can prevent the reactor from going critical in any accident scenario. However, both methods (unpoisoning / loading fuel into the reactor core on orbit) will likely require the use of In Space Assembly and Manufacturing (ISAM) technology to remove the safeguards and ensure the reactor is fully operational before use. This paper discusses the use of ISAMs to help with the unpackaging of anti-criticality devices on orbit along with ISAMs ability to help verify and preform maintenance and inspection checks of the reactor system before operation and in between engine burns.