I don't hold much hope for radar being used to search for debris in that environment. Surface borne India-band would be the only real option and that would need to be within say ten miles at the most to detect small pieces of debris. Sea clutter can be managed to a certain degree by adjusting gain / pin attenuation but that comes with the expense of loss of range.
Radar IMO would only be of any use once the debris range location has been already identified.