Facility Design Guidance

DOE-STD-6003-96

6. FACILITY DESIGN GUIDANCE

6.1 Introduction and General Guidance

This section describes an acceptable but not necessarily unique way to implement

DOE-STD-6002-96, "Safety of Magnetic Fusion Facilities: Safety Requirements," in the design

and construction of near-term deuterium-tritium (D-T) fusion facilities that will satisfy the intent

of Department of Energy (DOE) nonreactor nuclear safety requirements. To achieve adequate

safety, it is important to take safety into account as an inherent element in the design process,

beginning with conceptual design. Basic early design decisions, such as materials selection and

performance specifications, can have a significant impact on safety. A graded approach should

be used in the application of these safety design criteria to ensure that the level of detail

required and the magnitude of resources expended for the design are commensurate with the

facility's programmatic importance and the potential environmental, safety, and/or health impact

of normal operations and off-normal events, including design-basis events.

6.1.1 Design Basis

The facility design basis should specify the necessary capabilities of the facility to cope

with a specified range of operational states, maintenance, and other shutdown activities, as

well as off-normal conditions to meet the radiological and toxic material acceptance criteria in

DOE-STD-6002-96. The facility design should recognize that both internal (down to a probability

of 106/yr per event) and external challenges to all levels of defense may occur, and design

measures should be provided to ensure that key safety functions are accomplished and that

safety objectives can be met.

In establishing a set of external challenges, the design basis should include consideration

of natural phenomena (e.g., earthquakes, floods, high winds); environmental effects; and

dynamic effects (e.g., pipe ruptures, pipe whip, and missiles). The importance of these off-

normal events in the design basis should be evaluated based on the risk (both probability and

consequences) of these types of scenarios as identified by the event trees developed for the

facility safety analysis (see Chapter 5). Design-basis events should be specified in the safety

analysis and mitigated in the system design. The following are potential design-basis events for

fusion D-T facilities:

a. fusion overpower transient;

b. loss of flow or coolant pressure to actively cooled components;

c. loss of vacuum or vacuum pumping;

d. chemical reactions including hydrogen detonation;

e. site-generated missile impact from, for example, a catastrophic motor generator (MG)

set failure;