Model for ring closure in ER tubular network dynamics

Tubular networks of endoplasmic reticulum (ER) are dynamic structures whose steady-state conformations are maintained by a dynamic balance between the persistent generation and vanishing of the network elements. While factors producing the ER tubules and inter-tubular junctions have been investigated, the mechanisms behind their elimination remained unknown. Here we addressed the ER ring closure, the process resulting in the tubule and junction removal through constriction of the network unit-cells into junctional knots followed by the knot remodeling into regular junctions. We considered the ring closure to be driven by the tension existing in ER membranes. We modeled, computationally, the structures of the junctional knots containing internal nanopores and analyzed their tension dependence. We predicted an effective interaction between the nanopores facilitating the knot tightening and collapse of additional network unit cells. We analyzed the process of the pore sealing through membrane fission resulting in formation of regular junctions. Considering the hemi-fission as the rate-limiting stage of the fission reaction, we evaluated the membrane tensions guarantying the spontaneous character of the pore sealing. We concluded that feasible membrane tensions explain all stages of the ER ring closure.

Modelling of FPGA-based Reactor Protection Systems of an Experimental Power Reactor

The reactor protection system of nuclear power plants including an experimental power reactor which will be built by Indonesia is a safety system that actuates the control rods to be inserted in the reactor core to absorb the neutron to stop the fission reaction and then shut down the reactor (reactor trip). The reactor protection system (RPS) is actuated when the level of signals from the sensors of important components in the reactors deviates from the setpoint determined in the bi-stable processor of the RPS. RPS for the experimental power reactor has 3 redundant channels for reliability and to minimize fake signals from the sensors due to electrical noise. It can be done by selecting the channels in local coincidence logic in the RPS by voting 2 of 3 channels which are eligible to generate actuation signals to trip the reactor. Recently, the RPSs are based on the programmable logic controller (PLC). However, now the trend changes to FPGA-based RPS because of its simplicity and reliability. This paper investigates the model of the FPGA-based RPS for an experimental power reactor and the functionality of each component of the model. The results show that the model can represent the functionality of RPS for the experimental power reactor.

The Heat Transport System in a Heavy Water Nuclear Reactor

Nuclear power provided 10% of the world's electricity. In Ontario Nuclear provides the base electrical load on the grid. Nuclear power is very unique. It is able to release a tremendous amount of power if it is not controlled properly. There is three objectives that are required to be meet at all times when running a Nuclear power plant. These are called the three C’s. The three C’s are Control, Cool and Contain. The nuclear reaction in a power plant is required to be controlled, at all times. This is completed by maintaining the nuclear fission reaction in the reactor. The Nuclear fission reaction releases radioactivity. This radioactivity needs to be contained in the reactor and not released in the environment, at any cost. The reactor is required to be cooled at all times. This report will provide a basis on controlling the heat on a nuclear reactor. This design of the Instrumentation and Control of the Heat Transport System for a CANDU REACTOR, will be discussed in detail in this report. The Heat transport system is responsible to maintain the coolant mass balance of the nuclear power plant. The main control goal is to stabilize the water level at a reference value and to suppress the effect of various disturbances.

The study of prompt fission γ rays at the Oslo Cyclotron Laboratory

The study of prompt fission γ rays (PFGs) is crucial for understanding the energy and angular momentum distribution in fission, and over the last decade there has been an revived interest in this aspect of fission. We present the new experimental setup at the Oslo Cyclotron Laboratory for detecting PFGs resulting from charged particle-induced fission. Additionally, PFGs from the reaction 240Pu(d,pf) were measured in April 2018, and the fission gated proton-γ coincidence spectrum is shown. In order to explore the dependence of the PFG emission on the excitation energy and angular momentum of the compound nucleus, we plan several experiments where charged particle reactions are used to induce fission in various plutonium isotopes. The final results will be compared to predictions made by the Fission Reaction Event Yield Algorithm (FREYA) in an upcoming publication, to benchmark the current modelling of both the PFGs and the fission process.

ANALYSES OF INTEGRAL AND MOX CRITICAL EXPERIMENTS TO QUALIFY PARAGON2 PREDICTIONS*

This paper presents the qualification of the newly developed Westinghouse lattice physics code PARAGON2. PARAGON2 uses high energy resolution in the solution of the transport equation. The objective of this paper is to demonstrate that PARAGON2 accurately predicts the integral and critical experiments. The integral experiments are used to assess PARAGON2 predictions of fine neutronics parameters such as: resonance integrals and radial profiles of reactions rates, isotopics, and burnup for depleted pellets. The integral experiments considered are: the Hellstrand’s, TRX, and the PIE experiments. For critical experiments, this paper will focus only on VENUS-2 MOX critical experiment. The results obtained for the integral experiments clearly show the good predictions of PARAGON2 with the resonance scattering model which are close to measurement. The PARAGON2 predicted capture reaction rates, temperature coefficients, burnup and isotopic profiles match the measured values both in shape and magnitude. VENUS-2 reactivity prediction is in excellent agreement with the critical measurement value. Also, the standard deviations of measured minus predicted pin-wise fission reaction rates are very good (i.e. ≤ 2%) for both individual assemblies and the whole core.