Exigences relatives à l’instrumentation sismique des centrales et installations nucléaires

1.1 General

1.1.1 Requirements for nuclear power plants and nuclear facilities

This Standard describes the requirements for seismic instrumentation systems for nuclear power plants and nuclear facilities to monitor site-specific seismic responses. These plants and facilities include

(a) existing nuclear power plants and on-site nuclear facilities (e.g., spent fuel bays, dry fuel storage) (see Clause 4);

Note: "On-site" generally means within the protected area.

(b) new nuclear power plants and on-site nuclear facilities (e.g., spent fuel bays, dry fuel storage) (see Clause 5);

(c) new small reactors and on-site nuclear facilities (see Clause 6);

(d) new enriched fuel processing, fabrication, and storage facilities (see Clause 7); and

(e) new high- and intermediate-level radioactive waste storage facilities not in proximity to a nuclear power plant (see Clause 7).

Notes:

(1) "Existing nuclear power plants and nuclear facilities" refers to those licensed for operation prior to the publication date of this Standard.

(2) The requirements for new builds and existing plants might differ. Where requirements differ for new builds and existing plants, the difference is explicitly stated.

(3) "In proximity to" generally means either within the protected area or so close that the authority having jurisdiction (AHJ) judges that the instrumentation requirement in this Standard is satisfied by the instrumentation existing at the nuclear power plant.

1.1.2 Application for other nuclear facilities

This Standard is not required for, but may provide guidance to, other nuclear facilities that are under the jurisdiction of the Nuclear Safety and Control Act, such as

(a) existing small reactors;

(b) existing high- and intermediate-level radioactive waste storage facilities not associated with a nuclear power plant;

(c) nuclear substance processing facilities;

(d) low-level radioactive waste storage; and

(e) hospitals or nuclear research centres.

The operators of the facilities listed in Items (a) through (e) may, together with the AHJ, determine the applicability and suitability of the guidance provided by this Standard.

1.1.3 Scope exclusions

1.1.3.1 Seismic trigger units

Seismic trigger units (e.g., gas shut-off valves) are not considered in this Standard but can be used for specialized engineering applications.

Note: Trigger units are not part of a seismic instrumentation system.

1.1.3.2 Automatic shutdown

Automatic shutdown is not a seismic design requirement of this Standard; however, sufficient instrumentation of high reliability, as specified in this Standard, is needed to collect data in order to facilitate decision-making regarding continued safe operation, and the data could also be used in conjunction with other indicators to trip a reactor. Refer to Annex A.

1.2 Purpose

Where required to be installed, the purpose of seismic instrumentation is to

(a) measure the seismic response of the nuclear power plant or nuclear facility to the seismic ground motion;

(b) provide seismic motion parameters that can be used to determine whether the seismic design basis has been exceeded;

(c) generate seismic motion parameters that can be used in conjunction with inspections and testing of SSCs to determine whether the facility can continue operating; and

(d) provide input for validation of the dynamic analysis, as defined in CSA N289.3, of SSCs.

Notes:

(1) Nuclear power plant post-seismic response procedures (see Clause 6.5 of CSA N289.1) detail the inspections and testing requirements for safe shutdown, maintenance of fuel cooling, containment integrity, and monitoring.

(2) Annex A outlines criteria for seismic design basis exceedence of facility SSCs.

1.3 Terminology

In CSA standards, "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 (nonmandatory) to define their application.