APPLICATION OF ONE-DIMENSIONAL HYDROGEN EVENT PRESSURE PULSE PROPAGATION AND DIMINISHMENT MODEL TO ANALYSIS AND DESIGN OF HANFORD WTP PIPING

摘要

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) will process waste slurries capable of generating a dispersed non-condensable gas phase. Under postulated conditions, the generated bubbles may coalesce to form flammable gas pockets. Ignition of such a gas pocket may result in a deflagration or detonation that can transmit a pressure pulse into the surrounding gas-liquid slurry. The transmitted pressure pulses will impose structural loads on the piping and associated supports. These loads, and their evolution as the pressure pulse propagates throughout the system, must be considered in the design of WTP piping. Recent work has demonstrated good agreement between experimental data and predictions of the pressure diminishment associated with the propagation of a pressure pulse through a bubbly medium using a simplified one-dimensional pursuit model (i.e., model of rarefaction wave overtaking shock front). This paper describes the application of the pursuit model to flammable gas pocket scenarios postulated in the design of WTP piping. The model is adapted to consider the effect of the time-evolution of the ignited gas pocket and parametric simulations are used to demonstrate the effect of key variables on the propagation and diminishment of the pressure pulse in piping. The practical applicability of the pursuit model for WTP piping design /analysis is illustrated through the development of a correlation that appropriately represents the results of the pursuit model for a wide range of conditions and that could be readily incorporated into existing structural analysis tools. Arguments are presented supporting the applicability of the simplified model even for scenarios in which the ignited gas pocket does not satisfy the model's one-dimensional assumption.