. Announced United States Nuclear Tests -- By Event. Event Name - ’ Data (GCT) - Location | Type. - Purpose Yield Range Platypus Accidental release of radioactivity detected onsite only 02/24/62 NTS Shaft WeaponsRelated Low Pleasant 05/29/63 NTS Shaft WeaponsRelated Low 08/27/69 NTS Shaft WeaponsRelated Less than 20 kt 10/29/69 NTS Shaft WeaponsRelated 20 to 200 kt Pommard 03/14/68 NTS Shaft WeaponsRelated 1.5 ke Ponil 09/27/85 NTS Shaft Weapons Related Less than 20 kt Pool 03/17/76 NTS Shaft Weapons Related 200 to 500 kt Poplar 07/12/58 Bikini Barge Weapons Related Portmanteau 08/30/74 NTS Shaft Weapons Related 20 to 200 kt Portulaca 06/28/73 NTS Shaft WeaponsRelated 20 to 200 kt Post 04/09/55 NTS Tower Weapons Related 2 kt Presidio 04/22/87 NTS Shaft WeaponsRelated Less than 20 kt Priscilla 06/24/57 NTS Balloon WeaponsRelated 37 kt Project 56 No. 1 11/01/55 NTS Surface Safety Experiment Zero Project 56 No, 2 11/03/55 NTS Surface Safety Experiment Zero Project 56 No. 3 Pu dispersal 11/05/55 NTS Surface Safety Experiment Noyield Project 56 No. 4 01/18/56 NTS Surface Safety Experiment Very slight Accidental release of radioactivity detected onsite only Pliers Accidental release of radioactivity detected onsite only Pod Accidental release of radioactivity detectedoff site Pu dispersal Pu dispersal -91-