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Portsmouth’s X-326 Process Building.
NDA technicians perform the systematic monitoring approach.
PIKETON, Ohio – An alternative approach to determine how much remaining uranium is in piping and equipment should reduce time safely preparing the EM Portsmouth Gaseous Diffusion Plant’s three massive process buildings for demolition.
Original plans called for traditional quantitative nondestructive assay (NDA) measurements of all process equipment and piping. But Fluor-BWXT Portsmouth (FBP), EM’s D&D contractor, proposed the systematic monitoring approach, which provides the same level of assurance that the deactivation and decommissioning (D&D) can be safely completed, while saving considerable time.
Successfully deployed in D&D of the K-25 Building at Oak Ridge, the systematic monitoring approach uses gamma-ray scans to determine which piping contains uranium levels significantly below pre-determined conservative limits. Piping that falls below those limits may be left in the building for demolition, and quantitative NDA measurements will not be needed.
“Where appropriate to use, this new approach saves considerable project resources,” said FBP Nuclear Safety and Engineering Director Heatherly Dukes.
The 30-acre X-326 Process Building processed millions of pounds of uranium from the 1950s until 2001. Although equipment was cleaned, the process gas components that produced enriched uranium for national defense and commercial power generation still contain small amounts of residual uranium.
Almost all of the X-326 converters, compressors, and coolers have now been removed and shipped off site, but more than a hundred miles of process piping and thousands of pieces of support equipment remain in the building. The remaining items, along with surface contamination, will be characterized and surveyed before the building can be demolished to ensure nuclear criticality safety.
Testing showed the gamma-ray scans are effective in identifying uranium deposits in piping. More complex components, such as valves and expansion joints, will still be measured using traditional NDA measurement methods. To provide additional confidence, additional sections of piping are selected for traditional quantitative measurements. These measurements will be used to further verify the effectiveness of the scans.
Federal Project Director Jud Lilly said EM is encouraged by the alternative approach.
“FBP first got their arms around the NDA process and the quality requirements, then FBP developed, demonstrated, and verified a more efficient approach to performing some of this work while still meeting those same quality requirements,” he said.
Lilly added that the project hopes the systematic monitoring approach can be implemented in other areas to maintain quality requirements and improve efficiency.