Appendix II-A Design Control

DOESTD107393

APPENDIX lIA

DESIGN CONTROL

Design controls are the measures established to assure that the design process activities are carried

out in a planned, orderly, correct, and documented manner. These controls assure the quality of the

design requirements and design basis obtained through the design process. Design controls are

constraints to the design process that ensure the following results: the correct identification of design

inputs and constraints; the design analysis and calculations are complete and correct; and the design

outputs are complete and consistent with the design basis. Design controls are implemented through

procedures.

DOE 5700.6C, Quality Assurance, defines DOE design control requirements. ANSI/ASME NQA-1,

Quality Assurance Requirements for Nuclear Power Plants, provides additional guidance on design

control. Examples of design controls include:

Organizational responsibility for design functions

Training and qualification of engineering personnel

Information exchange and interface controls

Controls for preparation, review, approval, release, and revision of design documents

Document controls for maintenance and retention of design documents

Identification of appropriate design inputs and constraints

ldentification of required design output documents

Identification of required changes to facility configuration documents

Determination of quality levels, and acceptance standards

Programs to track cumulative effects of design changes

Design verification reviews

Requirements for and performance of design assurance reviews

Conduct of audits and management reviews

Conduct of corrective action programs

Design controls should provide some measure of assurance that proposed changes do not incorporate

the same design deficiencies built into the original design, if any exist. The design engineering

organization should not blindly accept previous design work as correct. Rather, it should maintain a

questioning attitude that considers the credentials, vintage, methods, and assumptions of previous

design work. Design controls should call for reasonableness checks of key calculations and

assumptions, and other calculations on a sample basis. In cases in which the original design is suspect

and in other specified cases, a zero-basis justification should be performed. The zero-basis justification

involves a clean sheet approach to critically review or reanalyze the system design requirements to an

appropriate interface point. Further, whenever new design requirements are issued for SSCs with

incomplete, inadequate, or missing design basis, critical portions of the SSCs' design basis should be

re-established at that time.

Programs to track cumulative effects of design changes are important design controls that are

sometimes overlooked. Critical load growths should be identified for tracking. If untracked, these load

growths might exceed the design capacities or design assumptions. Design verification checklists may

be used to track cumulative effects for variable design features such as loads on batteries or

emergency diesels, heatloads in equipment rooms, or weight loads on structures, including cable trays.

The checklist could identify the need to update the applicable load lists and take other necessary

actions. This approach can ensure that the design constraints imposed by previous designs are met.

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