RICHLAND -- Crews at the Hanford vitrification plant have lifted a 19-ton piping module over the 98-foot-tall walls of the plant's largest building, the Pretreatment Facility.
The module is the first and smallest of 13 complex piping modules that will be placed in the next few years, according to Department of Energy contractor Bechtel National.
The module was lowered into a space that provided less than two inches of clearance on each side and just a few feet on each end. It was set 56 feet above the ground.
The module was assembled at ground level by union pipefitters on a temporary steel structure outside the Pretreatment Facility.
"With such tight clearances, preassembly provides a safer working environment for our pipefitters because it allows them better accessibility and enables them to work at much lower heights," said Ray Patterson, area project manager for the facility.
Assembling the piping into modules before it is placed also increases efficiency because it allows piping, concrete and steel work to be done concurrently.
The module was placed in what will be one of the facility's highly radioactive areas, called a "black cell" because humans cannot enter when the plant begins pretreating radioactive waste. The black cell will house process equipment, which connects to the piping module, that will require no maintenance for the plant's planned 40-year lifespan.
"This pre-assembled module approach required extensive, detailed planning and collaboration during both the design and construction phases," said Wahed Abdul, DOE area project manager for the facility. "It was essential to ensure the modules were built and installed with precision and to the highest nuclear-quality standards."
Engineers used advanced technology, such as laser scanners that produced detailed three-dimensional images of the piping and the cells, to ensure accurate alignment and fit.
The module is 15 feet at its highest point and spans approximately 54 feet in length and 33 feet in width. It contains 3,900 linear feet of nuclear-quality stainless steel piping, ranging in size from 0.5 to 26 inches in diameter, and more than 70 pipe hangers.
The Pretreatment Facility is 79 percent designed and 37 percent constructed. The vitrification plant will be used to turn much of Hanford's 56 million gallons of radioactive waste held in underground tanks into a stable glass form for disposal. The Pretreatment Facility will separate the waste into high level and low activity radioactive waste.