Draft Details

1.1 General

This Standard defines requirements for the periodic inspection of balance of plant pressure-retaining systems, components, and supports that form part of a CANDU nuclear power plant using a risk informed in-service inspection (RI-ISI) methodology. Periodic inspection (see Annex A for additional guidance) is considered to include the fluid boundary portions of balance of plant systems, components, and piping, including their supports that comprise a complete nuclear power plant, excluding the following systems or portions thereof:

a) Systems, and systems connected thereto, containing the fluid that, under normal conditions, directly transports heat from nuclear fuel, and other systems whose failure can result in a significant release of radioactive substances.

Note: These systems or portions of systems are subject to periodic inspection in accordance with Clause 3.3.1 a) in CSA N285.4.

b) Systems essential for the safe shutdown of the reactor and/or the safe cooling of the nuclear fuel in the event of a process system failure.

Note: These systems or portions of systems are subject to periodic inspection in accordance with Clause 3.3.1 b) in CSA N285.4.

Compressors, turbines, generators, engines, internal components of vessels and heat exchangers, and hydraulic or pneumatic cylinders are exempt from the periodic inspection requirements of this Standard. This includes piping internal to equipment or mounted upon equipment that carries fluid from one chamber to another on the same foundation.

Note: To arrive at a periodic inspection program, the user should consider the examinations and tests performed by other programs such as pipe wall thinning, vessel examinations, equipment reliability, and maintenance programs in addition to RI-ISI. Examinations performed as part of supporting programs are not expected to be repeated in this periodic inspection program, but should be credited to this periodic inspection program to provide assurance that the program satisfies the intended purpose as described in Annex A. See Annex H for additional detail on crediting of examinations conducted by In-Service Inspection Programs.

1.2 Inclusions

This Standard addresses the following requirements:

a) failure aspects;

b) risk categorization of areas subject to periodic inspection;

c) provision for access;

d) examination techniques and procedures;

e) personnel qualifications;

f) frequency of periodic inspection;

g) responsibilities;

h) documentation;

i) records;

j) evaluation of periodic inspection results;

k) dispositioning; and

l) repair, replacement, and modification requirements.

1.3 Units of measure

The values given in SI units are the units of record for the purposes of this Standard. The values given in parentheses are for information and comparison only.

1.4 Terminology

In this Standard, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the Standard; “should” is used to express a recommendation or that which is advised but not required; and “may” is used to express an option or that which is permissible within the limits of the Standard.

Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.

Notes to tables and figures are considered part of the table or figure and may be written as requirements.

Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.

1.5 Application of Standard

The requirements of this periodic inspection standard are applicable to the operational phase of a nuclear power plant, until the fuel is removed from the entire reactor core and up to the time at which systems for cooling of the fuel are drained for the purpose of refurbishment or decommissioning of the reactor core.

This periodic inspection standard does contain requirements for providing access to components for pre-service and in-service examinations (part of the periodic inspection program), and hence the requirements of this standard should be taken into account during plant design and construction.

This periodic inspection standard does contain provisions for crediting of manufacturing and installation examinations as a baseline record for the periodic inspection program, and hence the requirements of this standard should be taken into account during plant construction.

This periodic inspection standard is not applicable to the decommissioning phase of the nuclear power plant life cycle.