Safe Return of Equipment

DOE-HDBK-6004-99

Safe Return of Equipment

Remote handling systems must be recoverable to a safe area for repair, without undo exposure to

personnel. The failure of a critical system must not prevent some secondary means of recovering that

equipment for repair, if its usage is required to continue operation.

Recommended Design Practices

Potential Safety Functions

Remote handling systems perform a number of safety functions to minimize personnel exposure to

radiation and other hazards during normal and off-normal conditions. In addition, system safety

functions may be required to prevent or mitigate the off-site consequences of off-normal events.

Potential safety functions include:

1. Erect portable radiation shielding panels

2. Place or relocate experimental devices or other equipment in high radiation fields

3. Test or inspect SSCs as necessary to assure performance of safety functions

4. Replace equipment or components in high radiation fields

5. Decontaminate SSCs in preparation for maintenance

6. Install/place diagnostic instruments

7. Install consequence mitigation devices in high radiation fields or otherwise unsafe conditions.

Safety Related-Design Guidance

Remote handling systems may be operated and stored near the fusion device in an area subject to

intense magnetic, thermal, neutron and gamma radiation environments. Persistent low levels of

hydrogen, deuterium, and tritium gases, as well as potential high levels of these gases during

unplanned events, may be present and should be considered in design. Activated dust from plasma

facing components may be present during maintenance or accident conditions and should be

considered. The design should accommodate the following general guidance:

1. The remote handling system should be designed such that the operator will not be exposed to a

whole body radiation dose rate greater than the current exposure limits.

2. Remote handling systems and components should not cause a collision with safety systems or

components while performing normal or abnormal plant maintenance. Wiring through sections

and / or modules of remote handling equipment should be provided within the equipment.

3. Allowances should be made for equipment movement so that, in performing intended operations,

safe distances can be maintained from personnel in normally accessible work areas.

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