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Highlights • A energy harvester using the gamma heating effect was conceptualized. • A energy harvester using the existing temperature within the canister was designed. • The thermal energy harvester can supply enough energy for the electronics for 50 years. Abstract Monitoring the conditions inside enclosed metal vessels as found in spent fuel canisters and nuclear reactor pressure vessels is crucial to ensuring safe dry cask storage and reactor operation. In this paper two energy harvesters, a gamma radiation energy harvester and a thermal energy harvester, are designed to power wireless through-wall communication and in-situ monitoring of interior conditions in nuclear canisters. Their performance over 50 years of service in the canister is analyzed using radiation and thermal modeling of the canister, and a scaled experiment is performed to validate the designs. The gamma radiation energy harvester was found to have an energy output of 17.8 mW during the first-year of canister storage. However, its power out decreases to less than 1.0 mW after 50-years storage. The thermal energy harvester proved to be more practical with a simulated power output of 93.9 mW and an experimental output of 46.3 mW even after 50-years storage in the canister. Cost-benefit analysis and discussion for both energy harvesters were also given. [ABSTRACT FROM AUTHOR]

A detailed three-dimensional thermal and fluid analysis of a vertical dry storage cask with a canister containing 32 high-burnup pressurized water reactor (PWR) spent fuel assemblies for a storage of 50 years was carried out using a CFD simulation. The input decay heat value was calculated based on a Westinghouse 17 × 17 PWR fuel assembly using the well validated package ORIGAMI imbedded in SCALE, with a total heat load of 38.44 kW for year 5 and 10.67 kW for year 55. The temperature-dependent and anisotropic thermal properties of the fuel assemblies, filling gas within the canister, and air covering the canister were considered in order to preserve accuracy. A peak temperature of 621.4 K occurred in the upper part of the fuel assemblies for at year 5, deceasing to 423.0 K after 50-year service. The simulation results shed light on the temperature and flow environment within the canister for an operational time of 50 years. [ABSTRACT FROM AUTHOR]

Safety is the most important issue in the development of nuclear energy. This paper reports experimental studies of a thermoelectric energy harvesting system designed for integration in a nuclear power plant capable of performing in radiation rich environments and producing enough power to run wireless sensors meant to increase plant safety. Furthermore, the system, which utilizes wasted heat present in coolant system piping, has the unique ability to provide power in both normal and accidental situations, to run the sensors without the need for external power. Two energy harvesting prototypes were designed utilizing a heat pipe for heat transfer. The first can supply a maximum power of 2.25 W using two Bi2Te3 thermoelectric modules of 2.79cm (1.1'') \times 2.79 cm (1.1”), in a source temperature near 250 °C. A second design was put forward to extend the application in higher-temperature primary loops, in which one PbTe-Bi2Te3 hybrid TEG module of 5.6cm (2.2'') \times 5.6 cm (2.2”) can provide a power of 3.0 W when the hot side temperature reaches 340 °C. In addition to the energy harvester, wireless communication circuits were developed along with an integrated power management circuit for wireless data transmission. A high intensity gamma radiation experiment was conducted during which each component was irradiated. A total dose of 200 kGy±10% (20M rads) was applied to the first prototype in order to approximate the expected lifetime accumulation for one implemented thermoelectric generator. Results showed that thermoelectric modules used in the prototype had no reduction in voltage output throughout irradiation. Throughout the experiment the harvester system witnessed a small voltage drop in open circuit voltage attributed to a reduction in heat pipe performance from radiation exposure. We also acquired a baseline radiation survivability level for non-hardened, non-shielded electronics of 10^2 Gy. [ABSTRACT FROM PUBLISHER]

This paper addresses the need for self-consistent simulation of mixed electrical and optical circuits and systems. Drawing on the use of modified nodal analysis (MNA) techniques ubiquitous in circuit simulation, an optical node is formulated which includes the magnitude and phase of the optical signal being simulated. This node consists of two propagating complex envelopes one for the forward direction and the other for the reverse direction. Using this formulation models are developed for a variety of devices including: lasers, photodiodes, multimode fiber, and optical connectors. The formulation allows for definition of multiple optical channels at different carrier frequencies, enables quick simulation of systems with large optical delays and optical interference effects. Several numerical examples are presented in this paper to illustrate the capability of the proposed framework and where practicable the results were compared to commercial simulators. These examples include a multimode fiber optical link, an integrated array of laser sources and a feedback controlled laser source used in a optical link with modulation achieved by the use of an electro-absorption device. [ABSTRACT FROM AUTHOR]

The thermoelectric generator (TEG) is a distinctive solid-state heat engine with great potential in various scale energy harvesting. Device-level heat transfer coupled with energy conversion makes the accurate analysis of the system very complicate. In this paper, the thermodynamic analysis in a TEG module is carried out to study the influence of the contact layer resistance, Thompson Effect, Joule heat, and thermo-pellet gap heat leakage on the performance of the TEG. All expressions of power output, current, matching load resistant factor, and efficiency of the device are derived and compared with a commercial module. The equations for the simplified model are also given concisely in order to give a full picture of TEG modeling. The research can evaluate the combined influence of all the factors and redress some derivations in the existing models. [ABSTRACT FROM AUTHOR]

A thermoelectric energy harvester composed of two thermoelectric modules, a wicked copper-water heat pipe, and finned heat sinks has been designed, modeled, and tested. The harvester is proposed to power sensor nodes on heating/cooling, steam, or exhaust pipes like these in power stations, chemical plants and vehicle systems. A model to analyze the heat transfer and thermoelectric performance of the energy harvesting system has been developed and validated against experiments. The results show that the model predicts the system power output and temperature response with reasonable accuracy. The model developed in this paper can be adapted for use with general heat sink, heat pipe, and thermoelectric systems. The design, incorporating a heat pipe and two 1.1″ by 1.1″ Bi 2 Te 3 modules generates 2.25 W ± 0.13 W power output with a temperature difference of 128 °C ± 1.12 °C and source temperature of 246 °C ± 1.9 °C, which is more than enough to operate wireless sensors or some actuators. The use of a heat pipe in this design increased the power output by 6 times over conventional designs. Based on the model, further improvement of the power output and energy harvesting efficiency of the system has been suggested by optimizing the number of thermoelectric modules. [ABSTRACT FROM AUTHOR]