Document: 10 CFR Part 50
Document ID: 1c9db254-4b16-4016-8411-63ac96dc3718
Document Type: cfr
Title: Environmental qualification of electric equipment important to safety for nuclear power plants.
Source: 10 CFR Part 50
Source URL: https://www.ecfr.gov/current/title-10/part-50/section-50.49
Revision Date: 
Chapter: 
Section ID: 50.49
CFR Part: 50
CFR Title: 10

Content:
preconditioning to an end-of-installed life condition is not practicable, the equipment may be preconditioned to a shorter designated life. The equipment must be replaced or refurbished at the end of this designated life unless ongoing qualification demonstrates that the item has additional life. ( 6 ) Submergence (if subject to being submerged). ( 7 ) Synergistic effects. Synergistic effects must be considered when these effects are believed to have a significant effect on equipment performance. ( 8 ) Margins. Margins must be applied to account for unquantified uncertainty, such as the effects of production variations and inaccuracies in test instruments. These margins are in addition to any conservatisms applied during the derivation of local environmental conditions of the equipment unless these conservatisms can be quantified and shown to contain appropriate margins. ( f ) Each item of electric equipment important to safety must be qualified by one of the following methods: ( 1 ) Testing an identical item of equipment under identical conditions or under similar conditions with a supporting analysis to show that the equipment to be qualified is acceptable. ( 2 ) Testing a similar item of equipment with a supporting analysis to show that the equipment to be qualified is acceptable. ( 3 ) Experience with identical or similar equipment under similar conditions with a supporting analysis to show that the equipment to be qualified is acceptable. ( 4 ) Analysis in combination with partial type test data that supports the analytical assumptions and conclusions. ( g ) Each holder of an operating license issued prior to February 22, 1983, shall, by May 20, 1983, identify the electric equipment important to safety within the scope of this section already qualified and submit a schedule for either the qualification to the provisions of this section or for the replacement of the remaining electric equipment important to safety within the scope of this section. This schedule