Combined Loads - hdbk60040053

DOE-HDBK-6004-99

Interaction Loads - Interaction loads should include the loads imposed on the tritium

systems by adjacent systems during normal or fault conditions.

Natural Phenomena Loads - Natural phenomena hazard loads should include loads

resulting from earthquake, wind, flood, tsunami and seiche. UCRL-15910 provides

guideline methods for establishing load levels and for evaluating the response of

structures, systems and components to the load levels.

Hydrogen Detonation Loads - Hydrogen detonation loads should include the mechanical

and thermal effects of tritium, deuterium and protium ignition or detonation, if the safety

analysis includes such failure as a design basis accident.

Missile Impact Loads - Missile impact loads should include missiles and pipe whip

resulting from failure of high energy systems, if the safety analysis includes such failure

as a design basis accident.

2. Combined Loads

Table I-1 lists the load combination which the design should consider for normal and anticipated off-

normal operations.

Because maintenance involves isolating, depressurizing and evacuating a system, the load during

maintenance is the static load only.

3. Cyclic Loads

Tritium systems are subject to thermal and pressure cyclic loadings during normal and anticipated off-

normal operation and maintenance. An evaluation should determine if a formal fatigue analysis is

necessary. ASME 93a or comparable computational methods provide criteria for the evaluation

which should use a conservative analysis for the number of cycles and service life including the

expected changes in material properties with time.

Structural Acceptance Criteria

Tritium systems that are safety-class should have design, fabrication, inspection and testing in

accordance with a recognized safety-class code such as the ASME Boiler and Pressure Vessel Code.

The specific codes and criteria selected should be commensurate with the level of safety required and

should have a technical justification.

Tritium systems that are NOT safety-class should have design, fabrication, inspection and testing in

accordance with a recognized national consensus code such as the ANSI/ASME Standard B31.3

"Chemical Plant and Petroleum Refinery Piping" (ANSI 93).

Structures, systems and components near a tritium system should be safety-class if their credible

failure could impact the safety function of a tritium system.