DNA 1240H-2 hazards were considered. Resultrc were calculated for two hotlers operating nt 120% of full power, and for ship entry times into the contaminated aeroso) ranging from 1 to 10 min after burst, and for ship exit times ranging from 7 to 20 min. The exact concentrution of fission-product activity in the aerosol produced by Shot Baker was not known, but was estimated to be between 0.1 and 4 curies/rt3. The external gamma doce to boiler-room personnel was then calculated “to be from 2 to 88 r, respectively. The study pointed out that if activity were absorbed on surfaces in the combustion air ducts, much higher doses could result to personnel exposed to the ducts. The inhalation hazards to personnel are discussed in Chapter 18, which deals with personnel hazards. A theoretical investigationwas carried out to estimate the significance of the doses due to contaminated ventilation air in below- decks spaces on a ship beyond the region of immobilization at the time of a shallow underweter burst. The investigation considered two cages: (1) all activity carried by the aerosol entering a below-decks space is deposited on the deck of the space; (2) all activity remains airborne and flows into and out of the space. It was assumed that no deposition of contaminant occurred in the ventilation ducts, and that the activity per unit volume of the aerosol entering the ship was the same as that surrounding the ship. Since the exact concentration of activity which would be produced in the aerosol by such a burst is unknown, the ventilation-air dose could not be computed directly, and instead was expressed as a fraction of the weather deck transit dose. Ratios were calculated for two ventilation conditions: (1) blowers OFF (ventilation by natural draft); (2) blowers ON (operating at rated capacity for var- ious speces). Ship entry times into the eserosol ranged from 0.3 min to 10 min; exit times, from 1 to 10 min. Results of the calculations indicated that, for the blowers OFF condition, the ventilation air dose was about 1.3% of the transit dose, and thus would be negligible. For the blowers ON condition, the ventilation air dose for 15 min (within the first half hour after burst) ranged from ahout 4% to 15% of the transit dose, and would be significant. The contact-beta and inhalation hazards to per- sonnel, which mlso may be considerable, are discussed in Chapter 18. If deposition occurred along the ventilation ducts, the ratio of the vent dose to the transit dose would be reduced in proportion to the amount of contaminant deposited, mit the ducts themselves would then hecome sources of radiation. Theoretical analyses indicated that, under certain conditions, the comtustion-air and ventilation-air systems of a ship could permit the ingress of contaminated aerosol to interior spaces of the ship, resulting in o complex radiological problem. Limited field-test experiments were carried out to determine the extent of the probdlem. 17-106 Cm mee ne = ee me ee 8 ee ee ee eeee -- pee ee eee -