pl Project 2.10 ~ Verification of Washdown Effectiveness as a Shipboard Radiological Countermeasure - M. M. Biggers OBJECTIVES Operation of YAG's and LST to be stationed in fallout area Rad Safe support for NRDL Projects Washdown evaluation DESCRIPTION AND EXPERIMENTAL PROCEDURES This project will document the procedures involved with the deploy-— ment and turn-about operations of the YAG's and LST. It will also report on the effectiveness of the washdown systen. 4 Ship Operations - Results The project ships, YAG-39, YAG-40 and LST-611, successfully conpleted their mission at shot CHEROKEE. The ships operated in Area 5, roughly N and NNW from Bikini Atoll at ranges as follows: YAG~ 40 YAG- 39 LST-611 - 40 miles - 70 miles - 100 miles YAG's 39 and 40 encountered small amounts of fallout measuring about 0.15 to 0.20 mr/hr on the deck, fallout. LST-611 received no measurable The ships were not closed nor was the washdown system activated. The YAG'ts 39 and 40 returned to Eniwetok Atoll on C £ 1 ani the LST-611 on C # 2, The ships were radiologically clean and no experi- mental or operational decontamination was performed. During the sortie, no major casualties of ships propulsion, auxiliaries, navigational, communications or control equipment were experienced. COMEDILOE LANL KC 7