Instrument and Control Systems

DOE-STD-6003-96

4. The surface finish of all external materials should allow for ease of decontamina-

tion. Highly polished, nonoxidizing, and nonpainted surfaces should be used so as

to not entrap radiological material.

5. The potential for hydrogen embrittlement and weakening of structural members

should be considered in all locations where exposure to hydrogen, deuterium, or

tritium is anticipated. High-stress components that see a significant tritium envi-

ronment should be monitored for hydrogen embrittlement.

6. The radiological activation of materials in areas of high gamma and neutron fluxes

should be considered in the choice of materials. This includes metals, greases,

fluids, and elastomers.

d. Instrument and Control Systems

The following I&C features should be provided in the design of the remote-handling

equipment as necessary to prevent damage to the handling equipment, to nearby safety-class

or safety-significant SSCs, and to the handled components; to provide for personnel safety; and

to remotely recover equipment (to prevent the necessity of personnel recovery of equipment):

1. Underload--An interlock actuated upon a reduction in load, while lowering with

grapple attached, at other than full down position, to prevent any further downward

travel.

2. Overload--An interlock actuated upon an unacceptable increase in hoisting force

to prevent upward travel.

3. Up-position--An interlock set at a predetermined operational limit to prevent any

further upward travel.

4. Down-position--An interlock set at the predetermined operational limit to prevent

any further down travel.

5. End-travel (hardstop)--Physical limit to translation.

6. Up-limit (hardstop)--Physical limitation to hoisting.

7. Slow zone--Region of travel where a reduction in hoist speed is mandatory and

automatic.

8. Nonsimultaneous motion--Automatic restriction against simultaneous hoisting and

translating motions.

9. Grapple release--An interlock to prevent opening a grapple under load.

10. Bridge travel--An interlock at a predetermined operational bridge travel limit.

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