Phlegmatic – unemotional or unenthusiastic

“There was nothing, nothing at all funny about a reactor leak. But Melekhin was known for his heavy sense of humor, and the doctor imagined that twenty years of working on reactors allowed him and the captain to view the potential dangers phlegmatically. Then, there was the implicit lesson in the story: never let someone who does not belong into the reactor spaces.”

thoughts of the soviet doctor, petrov, The hunt for red october, Tom Clancy