Loss of Liquid Lithium Coolant in an Accident in a DONES Test Cell Facility

A Demo-Oriented early NEutron Source (DONES) facility for material irradiation with nuclear is currently being designed. DONES aims to produce neutrons with fusion-relevant spectrum and fluence by means of D–Li stripping reactions occurring between a deuteron beam impacting a stable liquid lithium flowing film implementing the target. Given the hazard constituted by the liquid lithium inventory and the potential risk of reactions with water, air, and concrete eventually resulting in fire events, the Target Test Cell (TTC) is filled with helium and the reinforced concrete walls forming the bio-shield are covered with steel liners. A loss of Li in TTC, due to a large break in the Quench Tank, is postulated, and consequences are deterministically studied. With the TTC liner being water-cooled, the impact of the liner temperature rise following a leakage event is evaluated. Two separate MELCOR code models have been defined for the liquid lithium loop and water-cooled loop and are numerically coupled. The amount of leaked inventory dependent on the implemented safety logic and impact on TTC containment is evaluated. The water pressurization pattern within the liner cooling loop is studied to highlight possible risks of lithium–water/concrete reactions.

EVALUATION OF EQUILIBRIUM CORE OPERATION OF THE RSG-GAS REACTOR

The Indonesian Multipurpose Reactor, RSG-GAS reactor will accomplish its first lifetime in December 2020. The reactor has been operated in safe and reliable manner for about 33 years since it commenced in operation in 1987 to serve radioisotopes production, NAA, neutron beam experiments, material irradiation, and reactor physics experimental activities as well as training. The paper is intended to evaluate its in-core fuel management that is the conformance between the theory and implementation of the equilibrium core. Evaluation of the reactor operation parameter was carried out for core numbers 91 – 100. The data show that excess reactivity, shutdown reactivity and control rod reactivity have no significant difference at each core. The result shows that the BATAN-FUEL accurately determine the equilibrium core and its fuel loading pattern.This in-core fuel management of the RSG-GAS reactor supports the safety of reactor operation.

Effect Irradiation with 15 MeV Protons on Properties of 4H- SiC UV Detectors

The effect of irradiation by protons with an energy of 15 MeV with fluences of (1-40)٠1012 cm-2 on the spectral characteristics of UV 4H-SiC photodetectors was considered. Photodiodes with Schottky barriers were formed by thermal vacuum sputtering with a thickness of 20 nm and a diameter of 8 mm on 4H-SiC structures with CVD epitaxial layers with a concentration of uncompensated donors Nd-Na=(1-4)٠1014 cm-3 grown on n+-4H-SiC substrates. UV photodetectors withstand irradiation by protons with a fluences of 4٠1013 cm-2 with a photosensitivity improvement due to the gettering of simple radiation defects by localized cluster and amorphous areas, and partial structural improvement of the irradiated material. Irradiation of photodetectors by 15 MeV protons with a fluence of 4٠1012 cm-2 at a temperature of 2000 C led to an increase in quantum efficiency compared to samples irradiated in similar modes at 250 C due to an additional defective rearrangement.

Integration of Safety in IFMIF-DONES Design

The IFMIF-DONES (International Fusion Material Irradiation Facility-DEMO Oriented NEutron Source) facility is being designed with the general objective of providing irradiation of representative samples of power fusion machine materials under prototypical conditions. A linear accelerator will deliver deuterons at high intensity to circulating lithium in a loop, which will produce neutrons capable of obtaining the required damage conditions. As a result of this process, radionuclides will be produced as a by-product, which is characterized by several degrees of mobility. Shielding and radiation protection measures will be required in the facility. IFMIF-DONES will be classified as a first class radioactive facility according to national regulations, with Spain being the European candidate to site the facility. Several aspects of the main safety instructions affecting the facility’s design are explained and discussed in this paper.

Thermomechanical Safety Analyses for a 238Pu Production Target at the HFIR

Safety analyses at the high flux isotope reactor (HFIR) are required to qualify irradiation of production targets containing neptunium dioxide/aluminum cermet (NpO2/Al) pellets for the production of plutonium-238 (238Pu). High heat generation rates (HGRs) due to a fertile starting material (237Np), low melting temperatures, and previously unstudied material irradiation behavior (i.e., swelling/densification, fission gas release) require a sophisticated set of steady-state thermal simulations in order to ensure sufficient safety margins. Experience gained from previous models for preliminary target designs is incorporated into a more comprehensive production target model designed to qualify a target for three cycles of irradiation and illuminate potential in-reactor behavior of the target.