Biomass steam pretreatment is a key process in converting agricultural wastes to bioethanol. The pretreatment occurs in a large pressurized tank called a thermal reactor. Two key parameters influence the successfulness of the process: the reactor temperature, and the retention time. A particle pump pressurizes untreated biomass from atmospheric to reactor pressure with recycled steam from the r...

One of the actual problems of safe and reliable operation of NPP units with pressurized reactors is the development of tube plugging criterion for steam generator tubing. The basis for plugging criterion development is associated with existence of flaws with critical sizes at steam generator tubes. For effective application of this criterion the conditions of flaw instability should be analyzed...

This paper considers the modeling and control of a tubular fixed bed reactor with recycle stream for dimethyl ether (DME) production. For simulation purposes, a pseudo homogeneous model has been developed. By reactor simulation under steady state condition, effects of parameters such as feed rate, pressure and shell temperature are investigated. Using the steady state model, an optimizer that m...

Tarapur Atomic Power Station is a twin unit Boiling Water Reactors. The rated initial capacity of each unit was for 210 MWe. Subsequently due to Secondary Steam Generator tube leak problem, the units were de-rated to 160 MWe in the year 198485. The station has completed 36 years of successful commercial operation. TAPS reactor fuel channels are made of Zircaloy -4, material. These are used alon...

Best estimate system thermal-hydraulic codes in the nuclear engineering community, e.g., TRACE, RELAP3D, CATHARE-3, etc., were extended with 3D coarse-mesh components to better describe Thermal-Hydraulic (TH) phenomena taking place within Reactor Pressure Vessel (RPV) and core. The RPV is usually shaped like a cylinder while core mostly cube. Hence, TRACE code equipped Cylindrical VESSEL Cartes...

The significance determination process (SDP) provides a method to place inspection findings in context for risk significance in a manner that allows them to be combined with other plant performance results. This information is used to determine the level of NRC engagement in accordance with the Reactor Oversight Process. This appendix is used in conjunction with Inspection Procedure (IP) 71111....

Power generation in a nuclear plant is dependent on the Nuclear steam supply system (thermal energy source), the turbine generator (energy conversion), the circulating water system (heat rejection) and condensate/feed water system (regenerative heat and recycle of working fluid) and the plant electric system supporting these. These power generation processes must be operated so as to maintain e...

Two and three-dimensional simulations of experiments on atmosphere mixing and stratification in a nuclear power plant containment were performed with the code CFX4.4, with the inclusion of simple models for steam condensation. The purpose was to assess the applicability of the approach to simulate the behaviour of light gases in containments at accident conditions. The comparisons of experiment...

Important nuclear maintenance tasks, such as the steam generator nozzle dam placement, could be most effectively done by robotic systems. However, restricted teleoperator visibility and lack of absolute accuracy make such tasks very difficult to perform using conventional robotic control technology. In this paper, successful nozzle dam placement is achieved through a 3-D virtual viewing system ...