Energy Northwest reports two oil‑loss incidents; FSEC told discharges remained below detection limits

Columbia Generating Station staff updated the Energy Facilities Site Evaluation Council on two nonroutine oil‑loss events, describing responses, investigation status and corrective measures.

Kelly Elsa Fagan, providing the Columbia Generating Station update, summarized the August 15, 2025 event and a later February 15, 2026 event. She said an engineering evaluation reviewed by NPR Associates estimated "approximately 380 to 463 gallons of nonhazardous oil were released between May 31 and 08/17/2025" as the TOHX‑2 delta heat exchanger failed; that exchanger was removed from service and corrective measures were planned for the next refueling outage in spring 2027.

On the February 2026 event, Fagan said an oil‑water mixture was observed during startup and that "the maximum estimated release rate is 5.79 gallons of nonhazardous oil." She said staff promptly isolated the failed exchanger, placed backup equipment in service and notified Ecology, FSEC and the National Response Center on May 27, 2026 after completing initial investigations.

Fagan and staff said sampling and analysis did not detect laboratory‑verified oil concentrations above detection limits: "Water samples ... showed fats, oil, and grease concentrations below the laboratory detection limit of 5 milligrams per liter," she reported, and noted strengthened monitoring, enhanced inspection frequency and increased spill‑prevention awareness since the earlier event.

Council member Rivera thanked staff and noted the improvement in process and earlier detection: "I just wanna underscore the value of the process improvement that was put in place," Rivera said. Councilors had no further questions at the end of the update.

Energy Northwest told the council the failed heat exchangers will be inspected during the next refueling outage to confirm root cause and that replacement and additional corrective actions will be defined as needed. No enforcement action or formal council directive was announced during the June 17 meeting.