MAINTENANCE INSTRUCTIONS

Model 880 Delta, Model 880 Sigma and Model 880 Elite annual maintenance requirements

Model 880 Delta, Sigma and Elite exposure devices must receive inspection and maintenance at least once a year.

The locking mechanism and outlet port mechanism must be removed from the exposure device and disassembled for proper cleaning, inspection and lubrication on components that are critical to safety.

These procedures can only be performed on an empty exposure device, which requires transfer of the radioactive source assembly into an approved storage container.

The inspection and maintenance procedures must be performed by personnel specifically trained and qualified for this work. AEA Technology QSA service engineers will service these systems at one of their service centers or in the field upon request.

Trained and qualified personnel who wish to perform this work should use the following procedure:

1Perform a daily inspection of the system and transfer the radioactive source assembly into an approved storage container. Disengage remote controls and source guide tubes. The exposure device must be empty for the following steps. (See page 4.3)

2Remove the four 5/16-18 x 11/2in socket button-head screws that retain the locking mechanism plate from the empty Model 880 device using the tamperproof tool bit mounted in a ratchet.

3Remove the 10-32 socket head screws that retain the selector-ring and plunger lock housing from the mounting plate using a 5/32in Allen wrench.

4Disassemble the locking mechanism assembly, taking care not to lose the spring loaded parts. Place the disassembled locking mechanism components into a pan filled with fresh, clean solvent. Clean all parts using a brush to dislodge any dirt or grease. Remove cleaned parts from the solvent bath, dry and place on a clean surface. Inspect all parts for wear.

Replace worn parts as necessary.

Discard all used locking mechanism springs and replace with new springs.

When ordering spare parts, quote the model and serial number of the exposure device as well as the part number to ensure correct replacement.

Remove the lock retainer from the mounting plate by unscrewing the two 10-32 x 1/2in socket head screws using a 5/32in Allen wrench. Remove the plunger lock from the lock retainer by removing the cap screw using a 3/32in Allen wrench. Clean the lock plunger, lock retainer and springs in a solvent bath. Ensure the lock plunger is thoroughly rinsed to remove all dust from the key tumblers. Removed the cleaned parts from the solvent bath and dry thoroughly, using compressed air to dry the lock tumbler. Inspect all parts for wear. Replace worn parts as necessary. Lubricate the plunger lock barrel and tumbler using two drops of a light viscosity oil. Apply Vibratite™ thread sealant to the lock set screw and install. Check the plunger lock for proper function by using the key to engage and unlock. Apply Vibratite™ to the lock retainer's 10-32 x 1/2in screws, then mount the lock retainer to the locking mechanism plate. Hand-tighten the screws using a 5/32in Allen wrench.

Apply a light coating of lubrication to the inside surfaces of the selector ring and selector body using MIL-G-23827B or C, MIL-PRF-23827C grease or equivalent radiation resistant grease. Do not lubricate the lock slide and sleeve. Note that some types of greases may undergo chemical changes and form tars when exposed to radiation.

4.6