(Reuters) - Florida Power & Light shut Unit 4 at the Turkey Point nuclear power station in Florida Sunday night due to a likely valve issue, and is reducing power at Unit 1 at the St Lucie power plant due to salt build up in the switchyard, a spokesman at the U.S. Nuclear Regulatory Commission said Monday. He could not say whether the Turkey Point 4 outage was related to Hurricane Irma, which battered Florida over the weekend, and he could not say whether FPC planned to shut or just reduce St Lucie 1. 