| oy Wt: Froject 2.10 - Verification of Washdown Fffectiveness as a Shipboard Radiological Countermeasure - M. M. Biggers ORIJZOTIVES Operation of YAG's and LST to be stationed in fallout area. Rai Safe support for NRDL projects. Washdown evaluation, DESCRIPPION AND TYTeR IMNTAT PRoOcEDuRes This project documents the procedures involved with the deployment and turn-about operations ef the YAG's ani LST. IJI*t also reports on the effectiveness of the washdown systems, R'SULTS Ship Oncratiors The project ships, YAG~-39, YAS~-29, and LST-611, successfully pmran d completed their mission| The ships operated in _ areas N and NNW of Bikini at rengcs of about 40, $C, and 100 miles respectively for the YAG-40, YAG-39, and LST-611, The YAG-49 enccuntered fallout at EB # 3 hours on deck in the nonwasnidown area. The radiation fiela on deck in the non-washdown area peaked at about 9 r/hr at H # 7 hours. The ship was closed and the washdownwas in operation for a reriod of about 15 hours. On the after part of the ship where the washiown was activated, the dose rates were 15 to 25% of those forward. All operational equipment functioned satisfactorily. YAG~39 intercepted light fallout at about H # 10 hours on D-day, Activity slowly increased to 35 mr/hr at about H #18 hours and held fairly constant at that level until about H # 28 hours. - 57 - The washdown

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