Technical requirements for in-service evaluation of zirconium alloy pressure tubes in CANDU reactors
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This Standard specifies the technical requirements for the licensee to ensure structural integrity of cold-worked Zr-2.5 wt% Nb alloy pressure tubes in operating CANDU reactors. Clause 13 of CSA N285.0/N285.6 Series requires that when in-service inspection results or material surveillance results do not satisfy the requirements of the original inspection program, a fitness-for-service evaluation must be performed in accordance with CSA N285.4 to demonstrate acceptance. The requirements of CSA N285.8 address the specific fitness-for-service evaluation requirements of CSA N285.4, Clause 12.
This Standard applies only to cold-worked Zr-2.5 wt% Nb alloy pressure tubes in operating CANDU reactors and to evaluation of the volumetric inspection results, pressure tube to calandria tube contact, and material surveillance measurements listed herein. The definition of pressure tube material types is provided in CSA N285.0/N285.6 Series.
This Standard does not apply to evaluation of pressure tube dimensional changes (other than pressure tube to calandria tube contact), material property surveillance measurements beyond those defined in CSA N285.4, or to other reactor types. This Standard does not apply to pressure tube materials other than cold-worked Zr-2.5 wt% Nb.
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