Safety Functions and Structures, Systems, and Components

DOE-STD-6003-96

design-basis natural phenomenon: earthquake, flooding, severe winds, and so on.

However, any of these may be categorized as beyond-design-basis events depending on

the probability per event as assessed in the safety analysis. There are no specific design

requirements for beyond-design-basis events although such events may be considered in the

safety analysis process to quantify a range of hazards for site or public evacuation analysis.

The detailed design process should establish a set of requirements and limitations for

safe operation of the facility including consideration of

a. constraints on process variables and other important system parameters;

b. safety-class structures, systems and components (SSCs) settings;

c. requirements for maintenance, testing, and in-service inspection of the facility to

ensure the SSCs required to implement safety functions are within the design

envelope;

d. training requirements for facility personnel.

6.1.2 Safety Functions and Structures, Systems, and Components

Public safety functions as defined in DOE-STD-6002-96 are those essential characteris-

tics needed to ensure the safety of the facility and protection of the public and the environment.

DOE-STD-6002-96 defines the public safety function for fusion facilities as

confinement of radioactive (e.g., tritium, activated dust, activation and corrosion

products) and toxic (e.g., Be and V dust) materials.

SSCs required for the performance of a public safety function necessary to meet DOE-

STD-6002-96 evaluation guidelines should be designated as safety-class. This includes

supporting systems such as power, instrumentation and control (I&C), and cooling that directly

support a system performing such a public safety function (see Section 6.4). Safety-class items

should be subject to more formal and rigorous design, fabrication, and industrial test standards

and codes as well as an enhanced quality assurance (QA) program to increase the reliability of

the item and allow credit to be taken for its capabilities in the safety analysis process. These

SSCs should be designed to function in operational states and during and following off-normal

conditions, including design-basis events if credited to function in the safety analysis.

Associated with the public safety function are potential safety concerns that must be

addressed during the design process to minimize challenges to the public safety function.

Potential safety concerns associated with confinement of radioactive and/or toxic materials

should be considered: