Published on Sep 20, 2019
Nuclear microgenerators (Nuclear microbatteries) are micro scale power generators which convert radioactivity into electrical energy. They are generators that produce power without utilising any fusion or fission reaction. In nuclear micro batteries the energy of the spontaneously emitted Beta particle from the radioactive isotope is used to generate electric current. In the most recent type of nuclear micro battery, a radio isotope powered, self oscillating cantilever beam is used.
Description of Nuclear Micro Generator
The actuator realizes a direct collected-charge-to-motion conversion. A thin beam is placed at short distance from the radioactive source, and as the charged particles from the source are collected on the beam, it is attracted towards the source. As it contacts the source the beam is discharged and returns to its initial position. The process repeats and the cantilever oscillates continuously.
A static state model balancing the electrostatic and mechanical forces from an equivalent circuit leads to an analytic tractable solution for device performance and is presented. A piezoelectric crystal coupled with the cantilever can produce current pulses and finds revolutionary applications in microelectronics especially in MEMS and in nanotechnology.
One of the factors that hinder the exponential growth of micro and nano technological devices especially Micro Electro Mechanical Systems (MEMS) is the absence of onboard power supplies. MEMS technology provides integration of functionality in micro scale volumes, but similar scaling seems difficult for power sources. Hence, many investigators are paying more attention to the development of technologies for micro power supplies. Previously suggested power sources include fossil fuels, fuel cells, chemical batteries and solar energy.
Micro combustion based energy generation and micro-fuel-cells that aim to convert the mechanical, thermal and chemical energy into electricity are also proposed. These technologies still require external micro fluidics and external energy to drive the engine and to supply fuel into their working chamber, or to ignite the chemical reaction for energy conversion. Micro solar cell array have also been explored but need light.
This paper demonstrates the scope of nuclear microbatteries particularly a cantilever based micro generator for powering these devices. In this paper, a brief idea about different types of nuclear micro batteries are given and a detailed discussion of the theory, working, and performance of cantilever type are dealt with. The mathematical analysis of the microgenerator system is based on the electromechanical model developed, from which the equivalent circuit was derived.
Most of the commercial electronic equipments are using ordinary chemical batteries. These batteries are occupying a significant volume in the equipment than the circuitries. The most serious problem is that the battery size cannot be reduced beyond a limit. This is because of the low energy densities of ordinary chemical batteries. This paved the way to the development of nuclear batteries which have very high energy densities and long period of operation.