Design Constraints - doe-std-1073-20030025

DOE-STD-1073-2003

Configuration Management

exposure and aging on elastomeric materials, such as rubber O-rings and Teflon

tape.

Design Constraints are those general restrictions and limits to the engineering

design process that ensure consistency and quality of design (such as general

codes and standards, general regulatory commitments, quality assurance

requirements, engineering procedures and good practices, and adopted design

methodologies). In comparison to design inputs, design constraints are general in

nature; they apply to multiple classes and categories of designs and, therefore, to

many designs. For example, a design constraint for a safety system might be that

it will be able to accomplish its assigned safety function in the event of a single

failure.

Design Analysis and Calculations are those intermediate design products that are

necessary to convert the design inputs and constraints into appropriate and

complete design outputs. Design analysis and calculations consist of a wide

variety of engineering analyses, calculations, studies, reports, and technical

review checklists necessary to perform complete engineering design. Design

analyses and calculation capture the design assumptions and identify the available

design margin. The design margin is the conservatism between the specified

design requirement and the minimum requirement that could be developed from

the design basis. Examples of design analysis and calculations are:

transient analyses,

criticality analyses,

seismic stress calculations and analyses,

Equipment sizing calculations,

net positive suction head calculations, and

engineering evaluations of equipment qualifications and fire protection.

3.3.2 Design Output

Figure 3-4 also illustrates the design output documents, which are the products of the

design process that specify the design output requirements for the facility or activity

SSCs. The design output requirements are the composite result of the engineering

organization's consideration of the design inputs, design constraints, and design analysis

and calculations. Design output requirements specify that which is essential to support

the design basis, e.g., the necessary functions, capabilities, capacities, physical sizes and

dimensions, limits and setpoints. The design output requirements include the functional

requirements, as well as procurement requirements, quality assurance requirements,

construction/installation specifications and instructions, post-installation testing, post-

maintenance testing, and periodic surveillance/testing requirements. In some cases, the

design output requirements are also referred to as the "as designed conditions." The

design output documents identify the design requirements that dictate the physical

configuration of the facility. Design output requirements best support the configuration

management process objectives when they are documented in a format amenable for

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