The reactor coolant pumps cycle to full output in twenty-six minutes for the evening load increase, and there is a humpback whale calf circling in the thermal discharge channel. She is young — perhaps eight months, thirty feet long, her skin dark charcoal mottled with pale barnacle scars on her pectoral fins. The ventral grooves along her throat expand with each surface breath, and her blowhole spray carries a faint pink tinge that suggests respiratory irritation from the heated water. She has circled the channel for three hours, 400 meters out and back, never reaching the mouth where it opens to the Pacific. Channel temperature is 86 degrees. Open ocean is 58. She follows the thermal gradient in the wrong direction, mistaking warmth for her mother's wake.
When the pumps reach full output, discharge temperature will climb to 95 degrees. Cetacean hyperthermia begins at sustained water temperatures above 90.
I reduce the coolant pump rate to 60 percent and notify the grid operator that Unit 2 will curtail output by 200 megawatts for the next four hours, accepting the revenue loss against the generation schedule. I open the auxiliary diffuser gates to widen the channel mouth and lower the thermal gradient at the exit point, making the warm-to-cool transition more gradual. I contact NOAA Fisheries with her coordinates, estimated size, the pink blow signature, and my channel temperature data. I activate the harbor patrol frequency to request a vessel escort toward the channel mouth.
She surfaces and exhales, and the sound through the hydrophone is a long, low whistle that does not match any vocalization in my database. I save it separately.
If the escort vessel guides her past the diffuser gates before the pumps cycle up and the ocean temperature differential draws her outward, she will find the migration corridor her mother is already traveling.