Preventive maintenance checks are made on a schedule that can range from daily to annually at the nation’s only underground transuranic waste repository. Quarterly efforts taking about a week tackle more comprehensive items.
Once a year, a multi-week outage takes on the projects needing the greatest effort. This year’s annual maintenance outage spans Feb. 15 to April 14, eight weeks that include 97 planned work activities relying on personnel from six departments, including mine operations, waste handling, hoisting, work control, safety, and engineering. The effort includes a site-wide power outage to accommodate electrical work.
If the outage seems long, it is.
“This is most definitely one of the longest outages we have had in several years. The others have typically run four to five weeks,” said WIPP outage manager Andy Cooper.
The major scheduled work includes multiple large projects in the area of the waste hoist, including:
- Replacement of bulkheads, which control airflow in an area where waste is downloaded to the underground.
- Leveling of the waste station rails, which are railroad-like rails used for the transfer of waste pallets. Movement of the underground’s salt rock has heaved the floor so the rails are no longer level. The rails and adjacent metal plates will be removed, the floor will be leveled, and the tracks reinstalled. At the same time, the steel superstructure surrounding the bottom of the waste hoist will be raised, the floor leveled underneath, and the superstructure lowered back into place. The site’s salt hoist underwent a similar operation a year ago. The 2,300-horsepower salt hoist is the only means of hoisting mined salt from the underground.
Air is the lifeblood of the WIPP underground. Several of the site’s fans will undergo quarterly mechanical preventive maintenance and other improvements. Three of those fans, known as the 860-series fans, were installed at WIPP more than 20 years ago. Two other fans, known as the 960-series fans, have their own filtration units and were installed after a fire and radiological events in 2014.
The site’s supplemental ventilation system will also undergo preventive maintenance. That’s a large fan that provides air to the north end of the WIPP mine, as well as a southerly loop that supports mining in Panel 8. Each of WIPP’s eight panels consist of seven rooms that are 33 feet wide, 13 feet tall, and 300 feet long — about the length of a football field.
The waste handling areas will be improved, including:
- Ventilation testing and airflow balance in the contact-handled (CH) waste bay and Room 108, where workers handle TRUPACT-III casks.
- Smoke testing in the CH bay, Room 108, and the site-generated waste room to determine if the waste handling building’s ventilation system is pulling enough air.
- Exhaust fan replacement on the mezzanine level of the CH waste building. This extensive work is scheduled to take two weeks. The fan pulls air through a high-efficiency particulate air (HEPA) filter from around waste casks as they are being opened.
- CH bay annual preventive maintenance, including work on overhead cranes.
- Painting the floors in two waste handling buildings and a conveyance loading room to meet state requirements.
The WIPP site gets 13,800-volt power from an adjacent switching station. Part of the work during the power outage will be the testing and repair of a 13.8-kilovolt feeder cable between two onsite substations.