Examples of Design Requirements and Design Basis Information

DOESTD107393

Maintenance Requirements

- Preventive Maintenance

- Vendor requirements

Testing Requirements

- Post-modification testing

- Surveillance testing

- In-service inspection and testing

Construction and Installation Specifications

- Inspection requirements

Examples of Design Requirements and Design Basis Information.

System Level Design

Design Requirement: Emergency cooling system flow of 500 gpm must reach the reactor

vessel within 25 seconds after initiation signal.

Design Basis: The facility transient analysis assumes 500 gpm with a 25 second delay to

mitigate a small break loss-of-coolant accident. The actual engineering analysis provide

design margin for uncertainties by using 450 gpm with a 35 second delay. (ref. aa)

Design Requirement: Emergency electrical system must provide 1000 kW within 60 seconds of

initiation.

Design Basis: The nuclear safety electrical loads total 900 Kw. Cumulative additions to this

electrical load lists are tracked (ref. ee). The facility transient analysis identifies that no more

than 60 seconds elapse until emergency power is restored; the analysis assumes 85 seconds.

(ref. xy)

Design Requirement: Primary system water chemistry must be maintained with dissolved

oxygen between 500 and 1500 parts per billion.

Design Basis: Dissolved oxygen above 500 parts per billion is enough to keep nitrate stable.

Dissolved oxygen below 1500 parts per billion minimizes corrosion of stainless steel. (ref. fg)

Component Level Design

Design Requirement: Motor operated valve xyz must open in 10 seconds at 1 psid and 80

percent of rated voltage.

Design Basis: 10 seconds is desired in order to meet the system response time

requirement of emergency cooling system injection within 25 seconds at design basis

conditions. (ref. calc. jk)

II-B-7