Additional Assessment Needed Before Actual Waste is Introduced, Board Says
Mike Nartker
WC Monitor
5/30/2014
As the Department of Energy works to get the Idaho Integrated Waste Treatment Unit fully operational, the Defense Nuclear Facilities Safety Board is calling on DOE to consider performing additional assessments prior to the introduction of actual radioactive waste due to changes that have been made during startup testing performed to date. Last week, the Board sent DOE a report that outlined a number of concerns with how the Department performed a readiness assessment at the facility this spring as part of its startup preparations, and that listed new issues that have since been discovered that could take significant work to resolve. “Based on issues identified during the DOE RA and the continued identification of new design and operational issues during IWTU’s startup testing, the Board believes that additional independent assessment is warranted before the commencement of radioactive waste processing operations,” DNFSB Chairman Peter Winokur wrote in a May 23 letter.
Winokur added, “Throughout the DOE RA, and subsequent startup testing, the need for substantial changes to the facility’s safety basis, credited control set, component design, and operating procedures were identified. These changes have the potential to result in substantial revisions and modifications that have not been subjected to readiness reviews.”
Schedule for Full Operations Unclear
The new concerns from the DNFSB are the latest hurdle for DOE and cleanup contractor CH2M-WG Idaho (CWI) in their efforts to get the IWTU, also known as the Sodium-Bearing Waste Treatment Facility, up and operational. The facility is intended to treat the approximately 900,000 gallons of remaining liquid waste at the Idaho site through a steam reforming process for disposal and to allow for closure of the site’s remaining waste tanks. DOE previously had a commitment to the state of Idaho to complete the liquid waste processing by the end of 2012, but in the summer of that year, startup of the IWTU facility was significantly disrupted by what has been described as a “pressure event” that occurred when the facility’s filters became clogged with carbon material during efforts to get it up to its operating temperature. The facility was shut down and DOE and CWI implemented a set of modifications, the last of which were completed last summer.
Once the facility modifications were complete, DOE and CWI worked again to get the IWTU to its normal operating temperature and pressure, and then moved forward with a contractor readiness assessment and subsequent DOE readiness assessment. In late April, the facility entered into a planned outage period that was expected to last about a month to complete plant modifications and checks prior to the next phase of startup, which will entail introducing steam and a waste simulant into the facility. DOE has a new commitment to the state of Idaho to complete the liquid waste processing by the end of this year, but it remains unclear if that goal can be met. DOE had previously said the IWTU facility was expected to begin full operations this spring, but nether the DOE Idaho Operations Office nor CWI responded this week when asked what the new schedule is for beginning actual waste operations. DOE and CWI also did not respond this week when asked if they each believed the new commitment to the state of Idaho can still be met.
In separate statements, both the DOE Idaho Operations Office and CWI stressed this week they are working to safely begin full operations at the IWTU. “DOE is thoroughly evaluating the DNFSB conclusions identified in the letter and will continue to communicate with the Board on how to effectively integrate the safety measures and operational procedures required to safely proceed with nuclear operations. We value the feedback we have received from the Board as we continue to make progress with the startup of IWTU and transition to treating the remaining radioactive tank waste at Idaho,” Department spokeswoman Danielle Miller said in a written response.
CWI President and CEO Tom Dieter said, “Our top priority is, and has been since the beginning, the protection of workers, public and the environment. It has always been CWI’s position that the IWTU facility will not start with radioactive material operations until it is thoroughly tested and reviewed. The types of issues we identify and resolve during the testing phases are normal during any new facility start-up.” He added, “It’s important to remember that IWTU is a complex, first-of-a-kind facility that will treat a challenging waste form. We are exploring new territory with each subsequent stage of testing. Completion of this rigorous testing is intended to provide the necessary assurances and ultimate authorization to begin sodium bearing waste treatment.”
Questions Over DOE Assessment
In its report, DNFSB staff outlined a number of concerns with how the Department performed its readiness assessment. Among such concerns was that the IWTU’s off-gas system, which had been modified in the wake of the 2012 pressure event, was not operating at the beginning of the DOE readiness assessment. “The modified components had not yet been tested under their normal operating temperature, pressure, and flow conditions. Therefore, the effects of these design modifications on operating parameters throughout the rest of the IWTU plant, including on safety systems, were unknown. The staff team believes that without this information, it is not possible to make a defensible conclusion that the facility can proceed safely with nuclear waste processing operations,” the report says.
CWI managers later agreed to a request from DOE to commence heating up the off-gas system during the Department’s assessment. “This evolution required the resolution of 21 specific engineering actions, from procedural changes to calculating new process operating parameters. Similar additional engineering actions are required before IWTU can introduce steam, and eventually waste simulant, into the process system, which is necessary to complete DOE-ID’s IWTU startup plan,” the DNFSB report states, adding, “While conducting the off-gas system heatup, a Technical Safety Requirement (TSR) violation occurred due to a safety-significant system in the off-gas system not being properly configured for operation. Operators entered a Limiting Condition for Operations and shifted the facility to its warm standby mode.”
DNFSB staff also noted concern with DOE’s scheduling decision for its assessment. While there was initially planned to be a two-week break between CWI’s readiness assessment and the Department’s, DOE later chose to commence its assessment approximately 48 hours after approval of the contractor’s final report. “The extent of the corrective actions that would be required by the CRA’s pre-start findings was unknown at the time the decision was made to move up the start date of the DOE RA. The DOE RA team’s final report included a post-start finding that concluded that DOE-ID is not holding IWTU to the requirements of DOE Order 425.1D, that the DOE RA was not in compliance with the approved POA, and that acceleration of the schedule between the CRA and DOE RA led to compromises regarding compliance with DOE’s readiness process,” the DNFSB report states. “The Board’s staff review team believes that the decision to reduce the time between the CRA and the DOE RA negatively impacted the ability of the RA to fulfill the need for an independent assessment of facility operations.”
Technical Issues Continue to be Found
In addition, the Board report notes that technical issues have continued to be identified at the IWTU facility after the DOE readiness assessment was completed. “These issues appear to require significant engineering efforts to resolve and may result in changes to the IWTU safety basis and design. The magnitude of the engineering and operational changes may be significant enough to warrant independent review prior to the start of nuclear operations,” the report says.
As one example, Board staff cited concerns over “inadequate operation” of the IWTU’s hydrogen analyzer system. As part of the preparations to add steam to the facility, CWI engineers found that a gas sampling line was “unexpectedly cold,” according to the report. “Gas samples are drawn from the Process Gas Filter (PGF), routed through the hydrogen analyzer, and returned to the Denitration Mineralization Reformer. An eductor provides the motive force to move the sampled gas. The engineers directed a series of troubleshooting actions to determine if obstructions existed in the sample lines or the eductor, but found none. The engineers believe that the design of the eductor is inadequate to draw the required sample from the PGF. They are re-evaluating the eductor’s design and intend to procure a replacement,” the report says. It adds, “This situation highlights the consequences of the numerous unknowns associated with how the as-built IWTU facility operates.”
