The hazards we discussed above occur primarily on the exterior of the ship. We now need to discuss some of the radar hazards you may encounter inside the ship.

CATHODE-RAY TUBES (CRTs)

Cathode-ray tubes can be very dangerous and should always be handled with extreme caution. The glass envelope encloses a high vacuum, and because of its large surface area, is subject to considerable force by atmospheric pressure. (The total force on the surface of a 10-inch CRT is 3,750 pounds or nearly 2 tons; over 1,000 pounds is exerted on its face alone.) Proper handling and disposal instructions for a CRT are as follows:

Avoid scratching or striking the surface.

Do not use excessive force when you remove or replace the CRT in its deflection yoke or its socket.

Do not try to remove an electromagnetic CRT from its yoke until you have discharged the high voltage from the anode connector (hole).

Never hold a CRT by its neck.

When you set a CRT down, always place its face down on a thick piece of felt, rubber, or smooth cloth.

Always handle the CRT gently. Rough handling or a sharp blow on the service bench can displace the electrodes within the tube, causing faulty operation.

Wear safety glasses and gloves whenever you handle a CRT.

RADIOACTIVE ELECTRON TUBES

Electron tubes containing radioactive material are common to radar equipment. These tubes are known as Transmit-Receive (TR), antitransmit-receive (ATR), spark-gap, voltage-regulator, gas-switching, and cold-cathode gas-rectifier tubes. Some of these tubes contain radioactive material that has a dangerous intensity level. Such tubes are so marked according to military specifications. In addition, all equipment containing radioactive tubes must have a standard warning label attached where maintenance personnel can see it as they enter the equipment.

As long as these electron tubes remain intact and are not broken, no great hazard exists. However, if they are broken, the radioactive material may become a potential hazard.

The radioactivity in a normal collection of electron tubes in a maintenance shop does not approach a dangerous level, and the hazards of injury from exposure are slight. However, at major supply points, the storage of large quantities of radioactive electron tubes in a relatively small area may create a hazard. If you work in an area where a large quantity of radioactive tubes is stored, you should become thoroughly familiar with the safety practices contained in Radiation Health Protection Manual, NAVMED P-5055. By complying strictly with the prescribed safety precautions and procedures of this manual, you should be able to avoid accidents and maintain a work environment that is conducive to good health.

The hazardous materials information system (HMIS) contains a listing of radioactive tubes, along with proper stowage techniques and disposal procedures. Afloat Supply Procedures, NAVSUP P-485 contains detailed custody procedures. Be sure you use proper procedures whenever you dispose of a radioactive tube. Also, be aware that federal and state disposal regulations may vary.

Any time you handle radioactive electron tubes, take the following precautions:

1. Do not remove a radioactive tube from its carton until just before you actually install it.

2. When you remove a tube containing a radioactive material from equipment, place it in an appropriate carton to keep it from breaking.

3. Never carry a radioactive tube in your pocket, or elsewhere on your person, in such a way that could cause the tube to break.

4. If you do break a radioactive tube, notify the appropriate authority and obtain the services of qualified radiological personnel immediately. The basic procedures for cleaning the area are covered in the EIMB, General, Section 3. If you are authorized to clean the area, get a radioactive spill kit with all the materials to clean the area quickly and properly. The ship must have at least one radioactive spill disposal kit for its electronic spaces. It may have more, depending on the number and location of spaces in which radioactive tubes are used or stored. Each kit should contain the following items:

Container-Must be large enough to hold all cleanup materials and pieces of broken radioactive tubes and must be airtight. A three-pound coffee can with a plastic lid or 30/50 caliber ammo box is an acceptable container. The container must be clearly marked "RADIOACTIVE SPILL DISPOSAL KIT."

Rubber gloves-Two pairs of surgical latex gloves to prevent contact with contaminated material.

Forceps or hemostats-Used for picking up large pieces.

Masking tape-One roll of 2-inch-wide tape for picking up small pieces.

Gauze pads or rags-One stack of 4-inch gauze pads (50 pads or more) for wiping down the area. Do NOT use sponges.

Container of water-A small container of water (approximately 2 ounces) in an unbreakable container, for wetting the gauze pads or rags.

Boundary rope and appropriate signs-Used for marking the contaminated area.

Respirator-With filters that are specific for radionuclides.

Radioactive material stickers-For labeling the material to be disposed of. (These can be made locally).

Two 12-inch plastic bags-For containing the used material.

Procedures-Step-by-step cleanup procedures.

Other items recommended by the type commander and the fleet training group.

5. Isolate the immediate area of exposure to protect other personnel from possible contamination and exposure.

6. Follow the established procedures set forth in NAVMED P-5055.

7. Do not permit contaminated material to contact any part of your body.

8. Avoid breathing any vapor or dust that may be released by tube breakage.

9. Wear rubber or plastic gloves at all times during cleanup and decontamination procedures.

10. Use a HEPA filtered vacuum cleaner (with an approved disposal collection bag) to remove the pieces of the tube. The vacuum cleaner should be designated for "Spill Response" or "For Cleanup of Radioactive Materials ONLY" and use the standard magenta/yellow markings for labeling. If a vacuum cleaner is not available, use forceps and/or a wet cloth to wipe the affected area. In this case, be sure to make one stroke at a time. DO NOT use a back-and-forth motion. After each stroke, fold the cloth in half, always holding one clean side and using the other for the new stroke. (Dispose of the cloth in the manner stated in item 14.)

11. Do not allow any food or drink to be brought into the contaminated area or near any radioactive material.

12. Immediately after leaving a contaminated area, if you handled radioactive material in any way, remove any contaminated clothing. Also wash your hands and arms thoroughly with soap and water and rinse them with clean water.

13. Immediately notify a medical officer if you sustain a wound from a sharp radioactive object. If a medical officer can not reach the scene immediately, stimulate mild bleeding by applying pressure about the wound and using suction bulbs. DO NOT USE YOUR MOUTH. If the wound is a puncture type, or the opening is small, make an incision to promote free bleeding, and to enable cleaning and flushing of the wound.

14. When you clean a contaminated area, seal all debris, cleaning cloths, and collection bags in a container such as a plastic bag, heavy wax paper, or glass jar. Place the container in a steel can until it can be disposed of properly. Decontaminate, using soap and water, all tools and implements you used to remove a radioactive substance. Monitor the tools and implements for radiation with an authorized radiac set. They should emit less than 0.1 MR/HR at the surface. (MR/HR is the abbreviation for milliroentgen/hour,which is defined as a unit of radioactive dose of exposure.)

References to Consult Concerning Radioactive Tubes

The following is a basic list of publications conerning the handling and use of radioactive tubes.

- Department of Defense Hazardous Materials Information System (HMIS), DOD 6050.1-L

- Radiation Health Protection Manual, NAVMED P-5055

- Afloat Supply Procedures, NAVSUP P-485

- EIMB, General

- EIMB, Radiac

- Safety Precautions for Forces Afloat

- Naval Ships' Technical Manual, Chapter 400

Technical Assistance

For technical assistance and advice regarding identification, stowage, or disposal of radioactive tubes, contact: Officer In Charge Naval Sea Systems Command Detachment Radiological Affairs Support Officer (NAVSEADET, RASO)

Naval Weapons Station
Yorktown, VA 23691-5098