Recommended Design Practices

DOE-HDBK-6004-99

Recommended Design Practices

Use of a primary cooling system and a secondary cooling system is the recommended design to

comply with the general design criterion for containment of radioactivity assuming a single failure.

Closed heat exchangers are the recommended coupling between primary and secondary cooling

systems.

Use of multiple cooling loops in the primary and secondary systems is recommended as a design

feature to reduce the operational thermal-hydraulic transient associated with single (loop) failure.

Components and headers of systems should be designed to provide individual isolation capabilities

to ensure system function, control of system leakage, and allow system maintenance.

The use of leak before break (LBB) is recommended in the analysis of pipe break accidents. The

methodology described in section 3.6 of the Standard Review Plan, NUREG-0800 is recommended.

Generic System Descriptions

Fusion devices requiring cooling systems will usually radiate heat to the first wall of the plasma

chamber. The first wall will re-radiate heat to the shield wall. Cooling pipes in the shield wall will

remove the majority of the heat. The divertor provides a secondary but significant source of heat

which must be removed. Components such as the cryostat, vacuum pumps, magnetic coils will also

require some component cooling.

For further information on the latest new design, the International Thermonuclear Experimental

Reactor (ITERITER) has issued "ITER Outline Design Report," "ITER Outline Design Summary,"

and "Safety and Environment"(ITER). These documents provide generic descriptions of the cooling

systems.

Past Design Practices

Past design practice has been to provide defense in depth, redundancy of critical components or

systems and diversity. Some of these past practices may be applied to fusion machines. However,

the essential need for rigorous quality levels, impeccable safety standards and stringent regulations

will not be as applicable with the fusion machine. The needs of the fusion machine will be

investigated further before past design practices will be recommended for the fusion machine.

However, one may refer to International Thermonuclear Experimental Reactor (ITER)

documentation "ITER Outline Design Report," "ITER Outline Design Summary," and "Safety and

Environment" (ITER) for current information on current tokamak design practice.

ELECTRICAL POWER SYSTEMS

The electrical power system includes off-site sources and on-site AC/DC sources.

The switchyard is the interface between the grid and the facility receiving power from the off-site

grid. Power is transformed from the grid voltage (usually 345 or 500 kV) to the voltages which will

be used in the facility. Fusion device power supplies may be very large (500 MW) and of relatively