CSA N290.4:19

1.1 This Standard specifies requirements for the reactor control system (RCS) of water-cooled nuclear power plants (NPPs).

1.2 This Standard pertains to all components of the RCS, including mechanical, process, digital items, electrical, and instrumentation and control design used for the control of the neutron flux and the thermal power of the reactor. Note: Moderator purification systems which can be used to control flux are excluded from the scope of this Standard.

1.3 In this Standard, “control” refers to both manual and automatic action.

1.4 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.