You are correct in your understanding of FLAC as Lossless, however you misunderstand the functionality of FLAC when expecting to have the resulting FLAC file the same size and bitrate as the wav.
While Lossless, FLAC does use compression. But unlike a lossy format (like mp3) it does NOT remove any information, simply squeezing it into a smaller package by fitting all the "chunks" tightly together. Think of a document file that has been made into a Zip or Rar file, it becomes smaller when compressed but opens into the same as it's original prior to compression.
Simply put, it is like a wav file with the extra airspace removed and repackaged to hold tags. (When playing I believe it gets decompressed back into wav before going to your soundcard.)
If you were to transcode the FLAC file back into a Wav file, it would match the original ripped wav once again.
