A Nuclear Regulatory Commission (NRC) inspection of construction of the Mixed Oxide (MOX) Fuel Fabrication Facility identified two “apparent violations” involving structural welding by plant contractor CB&I AREVA MOX Services, according to a July 25 letter from the NRC to the firm.
The June 20-July 6 inspection reviewed an item that remained unresolved since a 2015 inspection identified “potentially inadequate welds” on some ledger assemblies that support floor panels in the Aqueous Polishing Building, a facility meant for the purification of weapon-grade material.
The MOX facility at the Department of Energy’s Savanah River Site in South Carolina is intended to convert 34 metric tons of weapon-grade plutonium into commercial nuclear fuel under a nonproliferation agreement with Russia. The Obama administration has sought to halt work on the unfinished facility in favor of an alternative dilute and dispose approach it says would be cheaper and faster.
One of the apparent violations involved the contractor’s failure to verify that the documents meant to certify that the welded ledger assemblies procured from Specialty Maintenance and Construction Inc. (SMCI) meet specifications indeed met those requirements. The second apparent violation involved failure to adequately audit SMCI, as these audit reports lacked “objective evidence of inspections or surveillances related to manual welding during their audits,” the letter said.
As a result, roughly 100 ledger assemblies were installed with deficiencies that included being undersize, shorter than the specified length, undercut, and with a “code prohibited joint design”; these assemblies required full capacity repairs to meet design requirements, it said.
The violations indicate deficiencies in the contractor’s quality assurance program in the areas of structural welding, oversight, and program implementation, the letter said.
“Without correction of the ledger deficiencies, any failures during future operations of the facility could have affected worker safety for workers in the rooms, and could have caused the failure of safety-related equipment in the impacted rooms, as well as cause other potential consequences,” the letter said, noting that the ledger assembly welds did not yield any actual nuclear safety consequences.
The two apparent violations are now “being considered for escalated enforcement action,” the NRC said. It noted that a final decision will depend on the status of corrective actions. The contractor now has 30 days to either respond in writing to the apparent violations or request a conference before the NRC makes an enforcement decision.
A July 26 letter from the NRC to the contractor said an investigation into whether an SMCI quality-control inspector falsified documents on safety-related welds found no evidence of “any kind of deliberate or willful misconduct” by SMCI, “even though they failed to meet the technical specifications of the ledger assemblies.”
“The findings point to inadequate training, a vendor going through a learning curve for nuclear work, and vague work instruction packages,” the letter said, noting that SMCI has since improved its nuclear program. “We plan no further action with regard to this matter,” the letter said.
The NRC held an open house in April to discuss its assessment of MOX activities last year, following a review in which it concluded that there were no construction activity areas needing improvement.
CB&I AREVA MOX Services spokespeople could not immediately be reached for comment.
