MSR Radiator 1 Radiator 1 1 Introduction Due to inefficiencies in the power conversion unit the reactor must generate extra heat waste heat which the radiator system must dissipate to prevent meltdown of the entire system The goal of the radiator group was to design a lightweight radiator that would dissipate the excess power from the MSR operating on either the Lunar or Martian surface This section will step through the process of choosing the radiator design and then present a detailed analysis of the chosen radiator First there is an overview of the specific requirements based on our proposed mission and the objectives agreed upon by the entire design team Next is an examination of the different radiator concepts that the group considered with analysis of the important facets of each The radiator group used decision methodology to determine the concepts that it would use in the design the third section breaks down this decision making process and explains the results Based on the conclusions of the concept analysis the fourth section describes the design the group chose and explores its important aspects The following section contains a summary of the analyses and calculations that the group performed in order to select and verify various parameters of the design Finally the sixth section will discuss ideas for future work 1 1 1 Goals The radiator design must take into account the five main programmatic goals for this design project 100 kWe 5 EFPY safe operation meets environmental regulations and works on the Moon and Mars All of these criteria have implications for the radiator s design parameters and the radiator group has embodied this in the decisions made throughout the design First the 100 kWe requirement combined with the efficiency and design of the power conversion system dictates the amount of waste heat that the reactor will generate and in what form that energy arrives at the radiator system Through much collaboration and compromise with the power conversion unit the selected PCU efficiency target was set at ten percent In this particular system given the 10 PCU efficiency the radiator must dissipate 900kWth for a 100kWe system and Next the design team had to ensure that the design was is robust enough to sustain five years of continuous operation Next Tthe safety and environmental protection guidelines required the group evaluate carefully the impact of the radiator s operation on the environment during both routine and abnormal conditions In this case the major safety and environmental threat is failure of a sufficient percentage of the radiator system to cause a core meltdown Finally any design the group considers must be able to function on the Moon and Mars which requires a constant consideration of the properties of both environments 1 MSR Radiator 1 1 2 Design Requirements From the overall design goals the radiator group created a set of more specific requirements These requirements pertain to how the radiator interacts with the other systems and the environment From the systems side consider how the radiator fits into the sequence of events from launch to surface operation first it must fit into the launch vehicle along with the other reactor components This means that not only must there be sufficient contiguous volume but also the weight of the radiator when added to the weight of the rest of the reactor must not exceed the available launch capacity This requirement necessitates give and take between the various design groups to arrive at the optimal parameters Second the radiator must be able to withstand the large g forces and vibrations associated with launch and landing without damaging itself or neighboring components Third the radiator must be in a configuration where it operates correctly after landing Whether or not there is unpacking required after the lander positions the reactor the radiator must be able to mate with the other systems and operate when the startup command is given This dictates consideration of the linkages between the radiator and the other components and its role in the reactor startup procedure Using the same sequence of events the design team generated the environmental requirements It is likely the radiator will contact the Earth s atmosphere when it is first constructed and packaged into the rocket The design must ensure that the high atmospheric pressure compared to its destinations does not damage any components and chemicals present in the air do not corrode or contaminated its surfaces Next during the rocket s transit from Earth to either the Moon or Mars the radiator will experience a microgravity environment and temperatures around zero Kelvin Once the radiator lands on the surface of the Moon or Mars the design team again must take into consideration gravity temperature 100 400K and chemical material reactions reactivity with the atmosphere and soil In addition since the radiator will begin to operate it is important to asses how operation interacts with the planetary environment 1 1 3 Scope With only the design goals and constraints given above this is still a very open design question In order to make the radiator design team s work efficient theThe range design team tailored the scope of the radiator design to a manageable set of design considerations of considerations was limited and it is important to Here we will describe understand what design aspects the team considered and which merit further analysis The primary considerations were that the design met the five goals outlined above and fulfilled the other design requirements as fully as possible In addition several other primary considerations drove the radiator group s reasoning Integration of the radiator with the other systems is critical in the creation of an overall tenable design for the MSR To this end the radiator group worked closely with the power conversion group which in turn collaborated with the core group to ensure that the three systems interfaced appropriately and to verify that the choices made by the 2 MSR Radiator radiator team met the entire design team s requirements Communication with the other groups was important for balancing mass and size issues and creating a geometry that complimented the rest of the system The environment is also a critical factor in our design since the peculiarities of the Martian and Lunar surface conditions control the effectiveness of a radiator The design group brought environmental factors into