Decouplable Radiation Shielding for Radioisotope-Powered Vehicles
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Solution Overview
Problem
Conventional nuclear reactor systems for vehicles, such as spacecraft, are hindered by the significant size and mass of radiation shielding needed to protect against radioisotope battery emissions, which affects performance and efficiency.
Innovation Solution
The implementation of a radioisotope power system with a strategically decouplable radiation shield that blocks radiation during preparation and ascent, and is then ejected to reduce mass, thereby enhancing the thrust-to-mass ratio and payload efficiency of the vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If radiation shielding is implemented to block radiation from radioisotope battery, then personnel and electronics are protected from radiation harm, but the mass and size of the vehicle increase significantly
Solution Approach 1:
The radiation shield is divided into a deployable portion and a retained portion. The deployable shield provides full radiation protection during launch and preparation when the vehicle is on the ground, while the retained shield provides minimal protection during space operations. This segmentation allows the vehicle to carry full shielding mass only when needed, significantly reducing operational mass.
Solution Approach 2:
The radiation shield transitions from a static, permanent structure to a dynamic, deployable system. The shield is deployed during ground operations and launch when radiation protection is critical, then collapsed or jettisoned during space operations where mass reduction is prioritized. This dynamic behavior optimizes the trade-off between radiation protection and mass across different mission phases.
2Reliability
If thick radiation shielding is used to reduce neutron fluence to safe levels, then radiation safety is improved, but the thickness and mass of the shielding structure increase
Solution Approach 1:
The shielding system is segmented into deployable and retained portions, with the deployable portion providing the additional thickness needed for ground safety while the retained portion provides minimal shielding during space operations. This eliminates the need for uniformly thick shielding throughout the entire mission duration.
Solution Approach 2:
Full radiation shielding is deployed during ground operations and launch when the vehicle is most vulnerable to radiation exposure. The shielding is then reduced after the vehicle reaches space, where radiation environments are different and mass reduction becomes the priority. This preliminary deployment ensures safety during critical ground-based phases.
3Object-affected harmful factors
If radiation shield is retained during space operations, then radiation protection is maintained, but the thrust to mass ratio and payload efficiency decrease
Solution Approach 1:
The shield is segmented so that only a minimal retained portion remains attached to the vehicle during space operations, while the bulk of the shielding mass is jettisoned. This retained portion provides sufficient protection for sensitive electronics while minimizing its impact on the vehicle's mass and performance characteristics.
Solution Approach 2:
The deployable radiation shield is discarded after serving its primary purpose during launch and ground operations. The shield's mass is no longer a burden during space operations, allowing the vehicle to achieve optimal thrust-to-mass ratio and payload efficiency for its mission objectives.
4Use of energy by moving object
If radioisotope battery is used to provide high power density, then energy efficiency is improved, but radiation emissions that can damage computer systems and harm humans are generated
Solution Approach 1:
The radiation protection function is extracted from the permanent vehicle structure and implemented as a separate, deployable shielding system. This allows the high-power-density radioisotope battery to be used for energy efficiency while the extracted shielding system provides radiation protection only when and where needed, rather than being a permanent mass penalty on the vehicle.
Solution Approach 2:
The radiation protection capability is made dynamic rather than static. The deployable shield can be activated when the radioisotope battery is being handled on the ground or when radiation protection is critical, then deactivated or collapsed during space operations. This dynamic approach allows the system to benefit from both high energy density and radiation protection as mission requirements change.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution increases the energy efficiency, mass efficiency, and duration capability of vehicles, allowing them to move faster for longer while protecting personnel and electronics from radiation.
Implementation Method 1
a radiation shield (105) configured to block radiation from the radioisotope battery (220)
Data Source
AI summary
Radiation shielding technologies for radioisotope battery-powered vehicles to protect computer systems and humans and increase the energy efficiency, mass efficiency, and duration capability of the vehicle during operation. A radioisotope power system includes a radioisotope power unit that emits a plurality of radiation particles. The radioisotope power system further includes a radiation shield configured to block a first radiation particle of the plurality of radiation particles. The radioisotope power system further includes a decoupling device configured to decouple the radiation shield from a vehicle. The radioisotope power unit can include one or more radioisotopes for power, propulsion, or both power and propulsion of the vehicle. The one or more radioisotopes can include an alpha emitting isotope, a beta emitting isotope, a gamma emitting isotope, or a combination thereof. The one or more radioisotopes can be for heat generation. The vehicle can be a spacecraft or an aircraft.