The Defense Nuclear Facilities Safety Board (DNFSB) says the design of a planned new ventilation system at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, N.M., does not do enough to prevent radiation from a possible underground accident from reaching the surface.
The board wants the U.S. Energy Department to respond to the concerns in writing by end of November, plus a briefing within 90 days, according to an Aug. 27 letter to Energy Secretary Rick Perry from DNFSB Chairman Bruce Hamilton.
In a staff report, the board said an underground accident, such as an explosion, could push radiation toward the exhaust shaft leading to the surface and then into the environment.
The current design of the WIPP safety significant confinement ventilation system (SSCVS), scheduled for operation around 2022, does not fully protect against radiation from an underground accident contaminating a building on the surface. Such a scenario could “cause a release of contaminated air into the environment,” the DNFSB said.
This is because the SSCVS continuous air monitoring system might not issue a signal fast enough for safety equipment to head off a radiological release at the surface, according to the DNFSB. The board’s staff found “even for a release that is immediately detected, a 60 second damper closure time may not be adequate to prevent radiological contamination” on the surface, the report says.
“The Department has received DNFSB’s letters and will be responding to them through the proper channels,” a DOE spokesperson said by email Thursday.
The Defense Nuclear Facilities Safety Board has no actual regulatory authority over the Energy Department. It can, however, make recommendations to the energy secretary. The energy secretary must then publicly explain why he will or will not follow the board’s advice.
The Energy Department’s underground disposal facility for defense-related transuranic waste went offline for nearly three years following an underground radiation release in February 2014. It resumed emplacing underground waste from DOE generators across the weapons complex in April 2017 – albeit at a dramatically reduced rate.
The current underground ventilation system operates with filtered air at a reduced flow rate, which cannot provide adequate air quality to support simultaneous salt mining, waste emplacement, and maintenance, according to managers at DOE’s Carlsbad Field Office, which oversees WIPP.
Once up and running, the new ventilation setup should increase airflow to about 540,000 cubic feet per minute, roughly triple the current level.
The Energy Department and WIPP prime contractor Nuclear Waste Partnership have already awarded more than $210 million worth of contracts for the primary ventilation system, along with a new utility shaft that would accompany it.
In addition to the new shaft and massive ventilation fans, the SSCVS project includes much new infrastructure on the surface – a new filter building, salt reduction building, and exterior duct work. In particular, the salt reduction building is at risk of contamination following an underground radioactive release, DNFSB said.
