RADIATION-MONITORING AND DECONTAMINATION TEAMS

A radiation-monitoring team will generally precede or accompany a repair party entering a gamma radiation field. Monitors serve as rad-safe support for repair parties. They make sure that appropriate precautions are taken to minimize exposure to gamma radiation and advise as necessary.

A monitoring team should consist of four persons: a monitor, a recorder, a marker and a messenger. The monitoring team will be equipped with a gamma-intensity radiac, a self-reading dosimeter, and materials for tabulating data. The team may be separate from the repair party, or it maybe made up of repair party personnel. They will use the radiacs periodically in the course of their work. One monitoring team can probably serve several repair parties working close together.

A radiation monitoring team can accompany decontamination teams for both technical and rad-safe support. It is organized as described previously and would function similarly.

As a part of a radiation monitoring team, you can help a decontamination team operate more efficiently by taking intensity readings of the area being decontaminated, before and after decontamination passes. Be especially careful to take the readings consistently and to inform the decontamination team of the effectiveness of its work. Gamma-intensity measurements are usually sufficient to locate the areas that need

Figure 8-19.-Gamma decay of fallout sample.

decontamination the most. Beta-radiation measurements may be required at hand-operated controls. In this case, use a beta-sensitive radiac.

A decontamination team, supported by a monitoring team, can concentrate on the locations having the highest radiation intensity.

Vary the monitoring technique in support of operations as required to suit the situation. When time is short and gamma-radiation levels are high, you should be concerned primarily with determining whether decontamination is reducing the gamma intensity. You should be taking measurements at the action stations during decontamination; the only measurements of importance are those taken at the actual locations to be occupied by personnel assigned to the stations. You should periodically note the improvement resulting from decontamination. Inform the decontamination crews when further decontamination appears impractical or when the acceptable intensity level has been reached.

After initial decontamination and when radiation levels are low enough so detailed monitoring can be performed without exceeding planning exposure levels, you can locate and identify hot

spots for the decontamination crews. You should note the general radiation level in the area and then locate hot spots. Locating hot spots with a radiac requires a detailed technique. Initially hold the radiac at waist height, and read the meter while moving slowly and steadily (so that body motion does not jiggle or sway the instrument's needle). Move side to side, and generally forward, until you determine a direction that gives the higher reading. You can further localize the hot spot by moving in the indicated direction until the radiac is within a few inches of the surface. Hot spots can often be readily suspected by the nature of the material in a given location. For example, cordage, rust, scale, and pools of water are likely to collect contamination.

After decontamination of the assigned area is completed, the monitoring teams should post the general intensity level and the computed maximum safe stay time, based on the planned exposure or the maximum permissible exposure (MPE). Radioactive decay should be ignored. Post this information in a conspicuous place, together with the time the reading was made. Teams should then report the final monitoring data, including the general intensity level.

When time is available and radiation levels are not high enough to be limiting, you can carry out the monitoring survey for either topside or interior decontamination in a detailed manner. Take readings before and after decontamination passes. After a decontamination pass, note the reduction in intensity in their assigned areas. If you find no significant reduction, inform the decontamination crews so that adjustments in the decontamination procedure can be made. After decontamination of the assigned area is completed, note the general intensity level, recheck the hot spots, take and check wipe samples as necessary, and report the final monitoring data. At this time, the monitoring teams should post the general intensity level in a conspicuous place, together with the time at which the reading was made. The safe stay time should also be posted if it is shorter than a normal watch.

SUMMARY

In this chapter, you have been introduced to nuclear bursts, effects, and countermeasures. You will need a good understanding of the radiac instruments since you will use them in the performance of your duties if you are assigned to the radiological monitoring team. When you conduct PMS on the radiac instruments, look them over and review the technical manuals supplied with the instruments. Discuss your repair party CBR assignments with your LPO so that you can relate the information presented in this chapter to your actual assignments. Review the various sections of this chapter as necessary until you are familiar with them. The information presented here may be used when an accident takes place during the handling of nuclear weapons, not just in the event of a nuclear war.