Computational modeling of accelerating corrosion in primary coolants of a typical PWR
High temperature and pressure environment along with large neutron and gamma-ray flux lead to significantly large corrosion in the stainless steel used in the primary coolant circuit of pressurized water reactors (PWRs). The corrosion products become activated in the reactor core upon circulation. Corrosion rate depends on reactor power and it can be a linear as well as a nonlinear function of time. Computer simulation offers a novel approach to study the effect of corrosion acceleration on coolant activity under transient conditions. We present two related mathematical models for corrosion acceleration under high temperature and flow rate transient conditions. In the first part of the work, we have formulated a mathematical model based on a system of coupled first order ordinary differential equations governing the isotopic concentration. In the second part, flow rate transients have been forced through non-homogeneous conditions. Numerical simulations show that for Na-24, Mn-56, Fe-59, Co-60 and Mo-99, the values of specific activities approach the equilibrium value fairly rapidly under normal operating conditions. Spikes are observed in the specific activity values of the primary coolant when corrosion acceleration and flow rate transients are employed in the model. Both the height and time of these spikes has been found to depend on the value of acceleration in corrosion.
Speciation and analysis of corrosion products in the primary coolant of pressurized water reactors
Abstract The procedure involves separate sampling and determination of the insoluble, cationic and anionic species of corrosion products (Fe, Ni, Cr, Mn, Co, Zn, Cu) in the primary coolant of pressurized water reactors (PWRs) with concentrations in the range 0–2000 mg l−1 boron and 0–5 mg l−1 lithium. Samples of coolant (0.2–1 l) are passed through packs consisting of one 0.45-μm filter paper, one cation-exchange membrane (Whatman SA-2) and one anion-exchange membrane (Whatman SB-2). The membranes are examined by wavelength-dispersive x-ray spectrometry. Selection of the ion-exchange membranes and the influence of the boron and lithium concentrations (and pH) on retention of soluble species are discussed. With sample volumes of 0.5 l, the detection limits are between 0.05 and 0.3 μg l−1 for undissolved species and from 0.03 to 0.14 μg l−1 for ions. Data collected during a PWR shutdown procedure are summarized.
Applying scenario technology analysis for new product dynamic strategic planning
This article intends to discuss the possibility of how to quickly improve the function of adaptive prediction direction for scenario analysis (SA) in technology-intensive industries. Therefore, this study is based on SA theory that combines the technology life cycle (TLC) viewpoint with the goal-oriented properties of path analysis model (PAM) to build an adapted SA for the purpose of dynamic technology forecasting. Using the goal-oriented properties of PAM, the adapted SA can quickly evaluate changes in the technical development of a market's dynamic schedule and can identify the gap between expectations and reality. This study proposes an adapted SA that allows the generation of both qualitative and quantitative scenarios that can be used as a helpful planning tool for dynamic assessment.