The program that helps maintain safety of material that accounts for one-third of the radioactivity of Hanford waste needs improvement, according to the Defense Nuclear Facilities Safety Board.
Its staff raised concerns after a review of the maintenance program at the Waste Encapsulation and Storage Facility, or WESF. The Department of Energy has 60 days to respond.
WESF stores 1,335 containers filled with cesium and 601 containers of strontium. In 1972, the two chemical elements, which generate substantial heat, were removed from Hanford's 177 underground tanks holding high- level radioactive waste from the past production of plutonium for the nation's nuclear weapons program.
The cesium and strontium capsules, which cast an eerie blue glow when the lights are turned off, are stored in a pool under water to shield workers from radiation.
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"The large quantity of radioactive material stored at WESF makes it imperative that all structures, systems and components serving a safety function be rigorously maintained and monitored," said defense board Chairman Peter Winokur in a letter to DOE.
As at other nuclear facilities, that requires a high degree of formality of maintenance operations and clear expectations from management, the letter said. In addition, all workers need to receive training specific to individual systems that help maintain safety, it said.
CH2M Hill Plateau Remediation Co. has performed 18 formal assessments in the past two years on elements of the WESF maintenance program, with only a need for one minor change identified, according to the defense board staff review.
"These results indicate to the staff that the contractor's oversight program may not be optimally effective or critical," the review said.
Given the significant issues identified by the defense board staff in its three-day review, DOE may want to evaluate the rigor of its contractor's program assessments, the review said.
The review's chief complaint was the quality and use of technical procedures at WESF.
Workers failed to catch readings out of the normal range on data sheets for water levels in the pool's cells and hot cell ventilation, the review said. The pool cell water levels are required to be verified weekly, but the data sheets for recording that do not have a place to record the method of verification, the review said.
In some cases, workers skipped steps outlined in written procedures if they could not be performed as written and performed actions that were not documented in tests of the stack radiation monitor system, the review said.
In other cases, workers used poor judgment during maintenance activities, the review said.
Workers found wet detector wires in an exhaust ventilation system, but they dried when the system was opened to perform repairs and the workers did not determine the source of the moisture, the review said.
In another instance, an operator indicated he did not understand how to read a complex gauge on a beta radiation monitor, so entered a reading from a remote computer monitor, the review said.
No training is offered specific to WESF, the review said.
However, specific training will become even more important because of the number of workers there near retirement age, the review said.
"The staff believes work force turnover at WESF will need to be managed prudently to ensure that knowledgeable and experienced personnel are available to maintain the WESF safety systems," the review said.
CH2M Hill promptly addressed several issues raised by the defense board staff, according to the review.
DOE recognizes the issues raised and is working with CH2M Hill on plans to address them, said DOE spokesman Geoff Tyree. DOE also will discuss issues with the defense board, he said.