Draft Details

Review start date:Jan 21, 2021
Review end date:Mar 22, 2021
Contact email:mary.morgan(at)csagroup.org
Draft Scope/Description:

This Standard covers the design, qualification, installation, commissioning, operation, maintenance, testing, inspection, and documentation requirements for systems providing heat removal from the reactor core to the ultimate heat sink(s) for water-cooled nuclear power plants during outages.

This standard does not cover requirements for design extension conditions (DEC). Requirements and principles for maintaining fuel cooling for outages during DECs, including requirements for emergency cooling water and power supplies, are covered in CSA N290.16.

This Standard covers only fuel cooling within the reactor core and does not cover spent fuel pool cooling, off-reactor fuelling operations, or the completely defueled core state.

The term “outage” refers to the following reactor states:

a)  a shutdown state where subcriticality is assured by physical means; or

Note: For CANDU reactors, this refers to a guaranteed shutdown state.

b) critical or sub-critical at any power where the normal (at high power) heat sinks are not the primary heat sinks.

Note: Examples of high power heat sinks include steaming of boilers to turbine or condensers.

For the purposes of this Standard, the outage commences when the normal (at high power) heat sinks are no longer the primary heat sinks.

The outage is considered to be terminated when the normal (at high power) heat sinks are re-established as part of the plan to proceed to sustained high power operation.

This Standard covers all systems that contribute to the transfer of heat by

a) conveying heat to the ultimate heat sink;
b) providing power or compressed air;
c) providing inventory makeup to heat sink systems; or
d) monitoring and control.

Note: The combination of systems or portions of systems that contribute to these functions are referred to in this Standard as “heat sinks”.

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.

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