If recommended by Western Sunfolk it will be decently secluded but, knowing the habits of the Usk it would be very dangerous in times of heavy flow. These happen when rain in the Brecon Beacons comes flooding down causing the river level to suddenly rise and the current to become fierce.
Careful observation of the weather will minimise this risk.

I have not been skinny-dipping there but I would not hesitate take advantage of the opportunity.

Have skinny dipped there and at a whole number of spots further down river including just north of the old railway bridge in Usk grid ref SO 373 015.
As a regular canoeist on the Usk I would dispute the argument that it rises fast.  peak flow at Usk is normally around 12 hours after peak rainfall in the Beacons, So if it isn't raining now and hasn't rained significantly in the last 24 hours the river will not rise.

As a regular canoeist on the Usk I would dispute the argument that it rises fast. 

Delighted to be corrected.

Thanks a lot for the information.

I'll check it in the summer and will report back.

What is the best time to swim in river Usk? when is the water temperature highest?

Water temperatures around here peak in September however subject to it not having rained hard recently, I normally start in May