The Department of Energy’s Waste Isolation Pilot Plant in New Mexico received 48 shipments of transuranic waste during December, finishing 2023 with 489 shipments, the most in a year since the facility reopened in 2017, according to DOE’s public website.

The 489 shipments shattered the 2022 mark of 272 shipments to the Waste Isolation Pilot Plant (WIPP), although the 48 shipments for the past month were down from 53 shipments in December 2022.

That is all according to the latest numbers as of Tuesday from WIPP’s public website. The final calendar-year 2023 shipment to WIPP arrived on Dec. 28, according to the website. WIPP management’s annual goal for 2023 was 400 shipments.

The Idaho National Laboratory was responsible for all but five December shipments to the disposal site near Carlsbad for defense-related transuranic waste. There were also four shipments from the Savannah River Site in South Carolina and one from the Los Alamos National Laboratory in New Mexico.

An underground radiation leak caused by a ruptured drum in February 2014 forced the salt mine disposal site offline for about three years. Prior to 2023, the busiest post-accident calendar year at WIPP was 2018, when the mine took in 311 shipments.

WIPP’s 473 shipments for fiscal 2023, which ended Sept. 30, was also a post-accident best. In the years prior to the accident, the underground salt mine would often approach 700 or more shipments per year. DOE and its Bechtel-led contractor are in the process of commissioning the new Safety Significant Confinement Ventilation System. WIPP managers say the new ventilation system should triple underground airflow and enable the facility to again approach pre-accident emplacement rates.