Application of Contemporary Technology to the Rehabilitation of Deteriorated Cooling Towers

摘要

From the 1960's to around 2000, approximately 100 large hyperbolic cooling towers (HCTs) with weights up to 160 meters or about 525 feet were constructed in the US. This period roughly coincides with the expansion of the nuclear power industry. Since 2000 apparently very few towers have been built in the US, with the Braydon Pt. project (Smith, 2013) reported at SEI 2013 featuring the first new towers constructed in many years. Of the large US towers some have been demolished, such as the iconic Trojan Tower in Washington State, and some have been permanently shut down, such as the Three Mile Island Towers, but many remain in operation, either continuously for base power production or intermittently for peak load demands. Given the age of these towers and the often severe service environments, it is expected that most are in need of rehabilitation. The consensus documents for cooling tower design and construction produced in the 1970s were widely used for the design and construction of many of the large towers during that era but have not been updated. While deteriorated towers have been cosmetically repaired, it is desirable in many cases to carry out the rehabilitation in a manner that facilitates the determination of the structural capacity and service life of the restored structure. Given the vintage of the original consensus documents, it is evident that they are an insufficient basis for the complete rehabilitation of existing towers. In the decades since the US recommendations were produced, there have been many advancements in design methodologies and assessment provisions and technology, primarily in Europe. In this paper, key factors that affect the rehabilitation of deteriorated towers are reviewed and prioritized with consideration of current capabilities and developments so as to provide a reasonable basis for restoring any lost structural capacity and extending the service life.