THERMAL-DEGRADATION OF THE CONCRETE ROOF OF HIGH-LEVEL WASTE STORAGE TANK

The DOE's high-level waste storage tank (HLWST) sites consist of singl e- and double-shell concrete tanks covered with soil overburden. Due t o the high temperature (212 degrees F and above) of the liquid-filled waste, the concrete walls and domed roofs are expected to endure therm al degradation which, in turn, may lead to cracking of the concrete. A remote video camera inspection of one such HLWST indicated some 'irre gularities' on the inner surface of the tank dome. A finite element mo del using ADINA was developed to simulate the field conditions includi ng concrete strength deterioration. The model was first validated agai nst the results obtained from tests conducted on a 1/10th-scale model. The analysis was then extended to study the actual field behavior. Th e results confirmed the overall structural integrity of the tank by co nsidering the global response of the tank and a detailed analysis of l ikely crack patterns in the dome area. The paper describes the complex ities in validating the scale model as well as prototype response. (C) 1997 Elsevier Science Ltd.