Staff Reports
NS&D Monitor
7/31/2015
The Y-12 nuclear weapons plant had 56 reported infractions related to nuclear criticality safety in Fiscal Year 2014, and the Oak Ridge plant received a rating of “meets expectations” in the annual review of nuclear criticality safety programs by the Department of Energy.
The number of infractions was down from 71 the previous year, although the rating remained same.
Most the infractions were “minor non-compliances,” according to Ellen Boatner, a spokeswoman for the plant’s managing contractor, Consolidated Nuclear Security, and did not pose a threat of a criticality accident – an uncontrolled nuclear chain reaction with severe release of radiation.
Y-12 stands out among plants in the U.S. nuclear weapons complex because it houses the nation’s largest inventory of weapons-grade uranium and handles the fissionable material is many forms and configurations that require tight controls and procedures.
“Fissile material operations at Y-12 involve high equity solutions processing, casting and a variety of operations dealing with various solid forms ranging from finely divided forms to large parts,” the DOE report stated.
“Because of the variety, forms and nature of enriched uranium materials handled at Y-12 combined with extensive administrative control and aged facilities the risk of a criticality accident is non-trivial and requires an intensive Nuclear Criticality Safety program implementation.”
The last criticality accident at Y-12 was in June 1958, and eight workers were hospitalized with acute radiation doses.
Y-12 is managed in conjunction with Pantex – the main warhead assembly and disassembly center near Amarillo,Texas – under a combined contract award to Bechtel-led CNS. The new management contract took effect July 1, 2014.
One of the National Nuclear Security Administration’s goals is to gain efficiencies and avoid redundancies under the combined contract, sharing some activities by the two plants.
Among those sharing arrangements could be personnel and expertise associated with nuclear criticality safety, according to information provided by CNS.
“With the combination of the sites under one contract, the total staff are now available to either site, should the need arise,” Boatner said in response to questions about the criticality safety report and the staffing levels of criticality safety personnel – which has been one of the concerns at Y-12 in recent years.
Pantex, like Y-12, received an overall grade of “meets expectations” for its efforts to prevent unplanned and uncontrolled nuclear events.
But there are significant differences in the reports of the two weapons plants in the 76-page report that addresses issues and improvements made at DOE sites during Fiscal Year 2014.
While Y-12 had 56 reported infractions on criticality issues, the report said, “There have been no known infractions in 22 years at Pantex.”
Boatner emphasized that “operations at Y-12 and Pantex are fundamentally different.”
She said, “The Y-12 site has many uranium processing operations that range from chemical operations to metal operations, where the form of uranium is changed. It is these processes that could pose a risk of a criticality accident. At Pantex, the fissionable material is fixed in a form that ensures subcriticality, so the risk of a criticality accident is not prevalent.”
Therefore, the personnel needs are apparently quite different.
Y-12 has dozens of criticality safety engineers on its staff, and Pantex has only two.
The report noted that FY 2014 was “unique” in that the managing operators for the two sites changed, combining under one company (Consolidated Nuclear Security). Therefore, two different rating systems were used, although the oversight by the NNSA Production Office – which took shape well in advance of the contract operations because of protests on the contract award — remained the same.
Boatner said safety, however, is equally important at both sites.
“In the area of nuclear criticality safety, every operation with fissionable material is methodically evaluated to establish multiple, defense-in-depth controls that ensure safety,” she said via email. “These controls project against every credible abnormal condition ranging from a procedural error to equipment malfunctions. Y-12 identifies and tracks even the most monitor condition, which enables CNS to take actions that continuously improve work processes and safety.”
Y-12 has reportedly had a tough time keeping enough expertise on staff to handle all the nuclear safety needs.
According to a chart in the report, Y-12 staff had 26 FTEs (full-time equivalents) for nuclear criticality engineers in 2014 and that number represented a shortage of about 12 FTEs based on the projected work scope for FY 2015.
It was reported that Y-12 was actively hiring 10 criticality safety engineers and that three had already been hired, but the time element for that statement was unclear.
“General improvements” were noted from the previous year (FY’13), the report noted.
There also are a reported 25 FTEs associated with criticality safety for the Uranium Processing Facility, which is under development. According to the DOE report, that includes 5 from the Y-12 prime contractor, and 24 subcontractors, meeting programmatic requirements.
There has been a shift in the way those personnel are accounted for because in FY 2013, the managing contract at Y-12 also was managing UPF. But under the current arrangement, Bechtel National Inc. is a subcontractor for the UPF work, and the overall number of criticality safety personnel are separated from the main workforce at Y-12.
The DOE report noted that NNSA Production Office/Y-12 was addressing staffing issues and has continued efforts to improve other areas, such as container labeling and “the process evaluations for criticality safety.”
Reviews by the NNSA Production Office “have reported an improvement in the area of NCS staffing as compared to the previous year, which considered this a major concern.”
As for the infractions, they varied in type and significance. The report said there were two “potential inadequacies of the safety analysis” related to criticality safety. There were two “management concern occurrences,” one of which involved an “unsuccessful casting of uranium alloy feed” at Y-12.
“The material was loaded into two furnaces for concurrent operation,” the report stated. “After lowering one casting stack from a furnace, the crucible split into two halves while cooling. Within minutes, the crucible continued to deteriorate, the uranium-alloy in the crucible continued to react, and the crucible and its contents progressively crumbled and fell into the spill ring and furnace bowl. Similar issues were noted in a second casting stack although not quite to the extent of the first. Administrative control was established and an NCS (nuclear criticality safety) deficiency was filed.”
Even though there are two plants managed under the same contract, the NPO’s oversight mission did not change, according to the report. Nor did the evaluation of contractors.
“NPO’s fee write-up per the annual Performance Evaluation Plan included discussion of criticality safety in an objective along with nuclear safety and safety system engineering," the report stated.
Other sites, such as Sandia National Lab, received the “meets expectations” rating. Los Alamos National Lab’s overall performance was said to be “improving, but still lags expectations.” Isotek, the company that is managing the disposition of the fissionable uranium-233 stocks at Oak Ridge National Laboratory, received an “excellent” performance rating for nuclear criticality safety.
