Design basis documents: What they are and why they are necessary
The U.S. Nuclear regulatory Commission (NRC) has been conducting safety system functional inspections (SSFIs) and safety system outage modification inspections (SSOMIs) since 1985. These inspections are somewhat different in approach. The SSFI is a system-oriented inspection as opposed to the SSOMI, which focuses attention on plant modifications. Both examine design in detail. A common thread emerging from these inspections is the unavailability of design basis information to support the as-configured system design and proposed plant modifications. The development of system-specific and topical design basis summary documents can markedly improve the modification process by providing a centralized access point for design basis information and a key to accessing the supporting design basis input, analyses, and output documents. The existence of these upper-tier design basis summary documents, however, is not a substitute for the supporting design basis documents. Design basis documents that support the as-configured plant design must be controlled and be readily available for use and reference by the engineering staff. A sufficient design basis must be available to support planned plant modifications such that a credible design verification can be performed in accordance with the guidance in ANSI N45.2.11-1974. If an adequate calculation basis does not exist to quantify the design margins remaining following a proposed modification, design analyses should be performed or recreated as necessary to support the final as-configured design of the system being modified.
- OSTI ID:
- 6835087
- Report Number(s):
- CONF-890604--
- Journal Information:
- Transactions of the American Nuclear Society; (USA), Journal Name: Transactions of the American Nuclear Society; (USA) Vol. 59; ISSN TANSA; ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
220200 -- Nuclear Reactor Technology-- Components & Accessories
220900* -- Nuclear Reactor Technology-- Reactor Safety
DESIGN
DIAGRAMS
DOCUMENTATION
ENGINEERED SAFETY SYSTEMS
ENGINEERING DRAWINGS
INSPECTION
MODIFICATIONS
NATIONAL ORGANIZATIONS
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
POWER PLANTS
QUALITY ASSURANCE
REACTOR SAFETY
SAFETY
THERMAL POWER PLANTS
US NRC
US ORGANIZATIONS