Nuclear Cogeneration of Methanol and Acetaldehyde from Ethylene Glycol Using Ionizing Radiation

Despite offering low-carbon and reliable energy, the utilization of nuclear energy is declining globally due to high upfront capital costs and longer returns on investments. Nuclear cogeneration of valuable chemicals from waste biomass-derived feedstocks could have beneficial impacts while harnessing the underutilized resource of ionizing energy. Here, we demonstrate selective methanol or acetaldehyde production from ethylene glycol, a feedstock derived from glycerol, a byproduct of biodiesel, using irradiations from a nuclear fission reactor. The influence of radiation quality, dose rate, and the absorbed dose of irradiations on radiochemical yields (G-value) has been studied. Under low-dose-rate, γ-only radiolysis during reactor shutdown rate

Simultaneous, robot-compatible γ-ray spectroscopy and imaging of an operating nuclear reactor

The design and test of a robot-compatible, radiation detection instrument providing simultaneous γ-ray imaging and γ-ray spectroscopy is described. The sensing system comprises a cerium bromide inorganic scintillation detector and a cylindrical, lead slot collimator that is configured with a robot-compatible, on-board data acquisition system. The mount for the sensor is a lightweight, bespoke 3-axis gimbal actuated by servos for pan, tilt and rotation of the collimator for imaging capability. This paper discusses the integration of this relatively low-cost radiation detection apparatus with a commercially available, Robot-Operating-System-controlled robotic platform (a Clearpath Robotics™ Jackal). The detection system is compliant with the power and mass payload constraints of the robot. Its performance has been evaluated by means of two practical examples: a) measurements in a laboratory environment to assess the ability of the system to resolve two caesium-137 point sources, and b) deployment at the Jožef Stefan Institute TRIGA Mark II research reactor to assess the ability of the system to characterise the γ-ray emission at 1 kW from a horizontal tangential beam port in the reactor hall and from the reactor sample pool above the core

On teaching experimental reactor physics in times of pandemic

The COVID-19 induced restrictions have prevented reactor physics students from attending in-person reactor physics exercises which are a vital part of their education. Jozef Stefan Institute has organized remote exercises with the help of off-the-shelf technology, including multiple videoconferencing setups, remote desktop software, portable cameras, a dome camera, shared spreadsheets, and a common whiteboard. The students were encouraged to actively participate in the exercises by giving instructions to the reactor operator, asking and answering questions, logging data, operating digital acquisition systems, and performing analysis during the exercise. The first remote exercises were organized as a five-day course of experimental reactor physics for students from Uppsala University. The feedback was collected after the course using an anonymous online form and was generally positive but has revealed some problems with sound quality which were resolved later. The Jozef Stefan Institute can also organize a remote course during a full lockdown when the reactor is not able to operate using the in-house developed Research Reactor Simulator based on a point kinetics approximation and a simple thermohydraulic module

The Integration of a CeBr3 Detector with a Submersible ROV for Reactor Assessment at Fukushima Daiichi

The premise behind this research is the characterisation and integration of a unique detector system on board a submersible, remotely-operated vehicle (ROV) for the end purpose of fuel debris characterisation at Fukushima Daiichi. Currently, at Fukushima Daiichi. Whilst precise knowledge of the location of the core debris at Fukushima is not known it is commonly assumed that fuel has leaked through into the base of the pedestal below and it is suggested that it may have moved outside of the pedestal into the lower plenum. The flooding of the reactor floors immediately following the Fukushima accident adds an extra element of complexity for the detection system requiring it to be submersible and to hold any detector system in water-tight confinement. The research presented here focusses on the use of a CeBr3 inorganic scintillator detector with a unique configuration of an in-built HV supply for ease of integration within an ROV in a submerged environment. The detector has been tested in several environments: small wave tank for source identification and a TRIGA reactor and a 60Co irradiator. It is hoped that the CeBr3 detector will constitute one component of an on-board detector payload to determine the suitability for the localisation and identification of fuel debris inside the cores at Fukushima