Safety-Class Design Standards and Criteria

DOE-HDBK-6004-99

Beyond design basis accidents include internal and external initiators whose frequency is lower than

the design basis frequency limit specified in the safety analysis.

Safety-Class Design Standards and Criteria

For safety-class tritium systems, the following design standards and criteria should apply to the

system, structures or components:

Structural

General

The tritium systems boundary is the pressure (or vacuum) confinement barrier afforded by the piping,

fittings, vessels, valves, and instrumentation that are wetted on their interior surfaces by tritium. The

boundary extends to the first or second isolation valve in system piping to the fusion device' vacuum

vessel.

Loads

1. Individual Loads

Tritium systems should withstand the static load, vacuum, normal operating pressure, normal

operating thermal load, electromagnetic loads (normal operating and fault), interaction loads from

adjacent systems, natural phenomena hazard loads and loads due to missile impact and hydrogen

detonation (if these are design basis accidents, see Section IV).

Static Load - The static load should include the weight of the equipment identified as

constituting the system (or component), and any supported hardware.

Vacuum Load - The vacuum load should include forces arising from complete vacuum

within the primary confinement barrier. A vacuum of <10-2 torr within the primary

confinement system is customary for cleansing prior to and following maintenance,

inspections, etc.

Normal Operating Pressure - Normal operating pressure loads should range up to and

include the design pressure of the system or components.

Normal Operating Thermal Load - The normal operating thermal load should include

temperatures associated with routine processing operations, both cryogenic and elevated,

and elevated bakeout conditions required for cleansing prior to equipment removal.

Electromagnetic Loads - Electromagnetic loads should include the forces induced as a

result of power, instrument and control and eddy currents in the tritium system interacting

with magnetic fields of the fusion machine' normal operation.

Electromagnetic Loads During Faults - Electromagnetic loads should include the loads

induced during abnormal operating events such as control failures, power supply failures,

bus opens or shorts, or magnet faults.