System Design Basis

DOESTD107393

A brief description of environmental limitations on system operation, such as normal

radiation fields and possible post-accident conditions;

Key instrumentation and control requirements to provide remote shutdown capability and

enable local monitoring of process activities and

System performance characteristics under various normal and infrequent operating modes

and off-normal operating conditions (examples include system head-flow characteristic

curves, natural circulation performance curves, and system hydraulic profile).

System Setpoints. Listing of important system setpoints with reference to design basis.

System Instrumentation and Alarms. Description of the requirements for instrumentation and

controls to ensure proper function and performance of the system. Description of alarm

capabilities.

System Interlocks. Descriptive information on interlocks with interfacing systems, the logic at

the interlock, and reference to logic diagram and bases of interlock.

SYSTEM DESIGN BASIS

The design basis information for a system DIS could be presented in the following DIS sections:

Authorization Basis. This DIS section describes those aspects of the design basis relied on by

DOE to authorize operation. The authorization basis is described in documents such as the

facility Safety Analysis Report and other safety analyses, hazard classification documents,

Technical Safety Requirements, DOE-issued Safety Evaluation Reports, and facility-specific

commitments made in order to satisfy DOE Orders or policies. This section may include

discussions of the applicable accident scenarios that require the system to operate and the

design inputs that need to be met. List any commitments to DOE.

Design Inputs. List important design inputs with emphasis on codes and standards. Identify the

original bases codes and standards (including year and addenda) adopted that specifically

apply to the DIS as a whole. Identify NRC and commercial nuclear codes and standards

adopted. List applicable DOE Orders, rules, and standards. Identify any exceptions to

requirements that are reflected in the design. The applicable codes and standards should be

listed along with a reference to the commitment to DOE. Identify whether the codes are

optional or required (committed). Any exceptions to, or interpretations of, these requirements

that are applicable to the current facility design are provided.

Design Constraints. List and/or reference applicable system design constraints, including

design procedures, methods, and guidelines.

Design Analysis and Calculations. List and/or reference applicable system design analysis and

calculations.

COMPONENT REQUIREMENTS AND BASIS

Major components often merit being addressed separately and uniquely. A separate DIS section on

component information addresses important component design information without breaking the flow of

system-level design information. Identify major system components. Identify important classes of

components within the system, such as motor-operated valves. Provide component-level design

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