Table 5.1. Safety system functional requirements

DOE-STD-6003-96

The design of the SSCs that perform the safety-class and safety-significant safety func-

tions should meet the appropriate requirements established in Table 5.1.

TABLE 5.1. Safety system functional requirements

Requirement

Safety-Class Safety Function

Safety-Significant Safety Function

System design

Reliable methods of accomplishing the required

Nonredundant systems are normally used to

safety function should be provided. Some of the

perform the worker safety function. The safety

design techniques that would ensure system

system should be analyzed to preclude failures

reliability would include redundancy, diversity,

mechanisms that could disrupt the system

simplicity in design, independence, fail safe, fault

function. Multiple systems may be employed, at

tolerant. Each method should be analyzed to identify

the discretion of the facility developer, to ensure

potential failure mechanisms from performing the

that the system functions are performed.

safety function in the system and to minimize those

failures in the design. For further guidance on

providing reliable system designs, see

Section 6.7.3.1.

Codes and

Nationally accepted design codes should be used in

The codes and standards used for these systems

Standards

the design (see Chapter 6). The applicability,

should be those which have been validated

adequacy, and sufficiency of the codes and

through satisfactory performance in commercial

standards used should be evaluated. These codes

application.

and standards should be supplemented or modified

as necessary to ensure system performance in

keeping with the importance of the safety functions

to be performed.

Reliability

The safety system should be equivalent to that

Safety system should be demonstrated to have a

associated with commercial industrial safety

high reliability. One of the ways to demonstrate this

practices.

is by providing multiple, redundant, diverse

systems/barriers to accomplish the safety function.

Quality

The SSCs should require an appropriate level of

The systems required should be designed

quality for the design and construction to ensure the

in accordance with industrial quality requirements.

system function is performed. Quality assurance in

accordance with the requirements of 10 CFR

830.120 should be implemented.

Testability/

The SSCs should be tested/surveyed periodically to

The SSCs should be tested/surveyed periodically

determine that the function can be provided.

to determine that the function can be provided.

surveillance

Acceptance criteria should be established to

evaluate the test results that demonstrate when the

system is performing its intended function. The test

frequency should be established to ensure that the

system demand and reliability requirements are

achieved.

Natural

Design for natural phenomena should be in

The SSCs should be designed to withstand

phenomena

accordance with facility performance goals per

appropriate natural phenomena and continue to

DOE Order 420.1 (DOE 1995a).

provide the required safety function. Design for

natural phenomena should be in accordance with

facility performance goals per DOE Order 420.1

(DOE 1995a).