Two types of surveys are usually conducted—arapid, or gross, survey and a detailed survey.The rapid survey is a preliminary reconnaissance.Limited numbers of readings are taken in a minimumamount of time. The purpose of the rapid survey is toobtain a quick estimate of radiation levels at specifiedlocations to determine the possibility of keepingstations manned.A detailed survey is used to determine theeffectiveness of decontamination measures. Allaccessible areas and equipment are surveyed in a slow,methodical manner. Special attention is paid to areasthat tend to hold contamination (rust spots, caulking inwood decks, canvas, rope, and so on).Each member of a monitoring team wears aprotective mask and clothing and is equipped with botha pocket dosimeter and a high-range casualty dosimeter.No member with an open cut or wound should enter anycontaminated area. Smoking, drinking, and eating areprohibited in contaminated areas.CBR CONTAMINATION MARKERSA standard system is used to mark areascontaminated by CW, BW, or nuclear agents. Look atfigure 13-6, which shows CBR contamination markers.The markers are triangular in shape, with a base ofapproximately 11 1/2 inches and sides of about 8 inches.Each type of contamination is readily identified by thecolor of the marker. Additionally, they are labeled GAS,BIO, or ATOM, as appropriate. The front of the markerindicates the safe limits of the contaminated area. Nevergo beyond the markers without permission. The frontof each marker also contains information about thecontaminated area, such as the date and time ofdetection and the type of agent.NUCLEAR RADIATIONWhen a ship is exposed to radiation or isradiologically contaminated (such as from a base surgeor fallout), surveys are made to determine the degree ofcontamination.During surveys, two types of measurement aremade—intensity (dose rate) of the radiation field andthe total amount (dose) received. This information isused to calculate (find) the safe entry time (time afterexposure when an area may be entered safely) and staytime (length of time a person may remain in an areawithout exceeding permissible radiation exposurelevels). Dose rate is expressed in roentgens (gamma raymeasurement only). The total dose is expressed in rads(any type of radiation).One measurement instrument is the radiac meter(radiac stands for radioactivity detection, indication,and computation). Usually, only qualified damagecontrol (DC) personnel use the radiac meter; therefore,only the personnel dosimeter is covered here.Measurements are made using two basic types ofpersonnel dosimeters—self-reading and nonself-reading.The self-reading pocket dosimeter (fig. 13-7) isabout the size and shape of a fountain pen and comes inthe following ranges:0 to 5 roentgens0 to 200 roentgens0 to 600 roentgens0 to 200 milliroentgensSelf-reading instruments measure exposure toradiation over a period of time, not dose rates at anygiven time. Hold the dosimeter up to a light source and13-14Student Notes:Figure 13-5.—General outline of contaminated areas on weather decks.
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