Operations

DOE-STD-3024-98

alarms) and the purpose of the setpoints. The

4.1.6.5

Interlocks, Bypasses, and Permissives

values of setpoints and other system limitations shall

be correlated with the system requirements,

This section shall identify interlocks, automatic and

especially TSR-required setpoints.

manual operating bypasses, permissives, and other

design constraints or conditions associated with the

Note: It is common practice to include

system being described. For example, the function

setpoints and limitations information in

of a particular safety system may become available

a set of tables in a stand-alone

automatically after system pressure exceeds a

document that contains such

specified value, but be deactivated below this

information for numerous systems.

pressure to prevent inadvertent actuation when the

When a setpoint entry is made into the

system is operating within a pressure range for

table, the entry needs to identify the

which the safety function is not needed. Interlocks

adjustment by name, where the

provided to prevent or permit certain system actions

adjustment is located physically, where

or responses only when specific conditions are met

and how the adjusted value is

shall be listed. Provisions for manually disabling,

determined, the nominal value of the

bypassing or otherwise altering system performance,

adjustment, the range of acceptable

and the conditions and limitations under which they

values for the setpoint, and the bases

are to be used shall be identified and explained.

for the values. The acceptable ranges

need to be specified in actual values,

not as tolerances, percentages, or other

4.2 Operations

approaches that necessitate

calculations.

In this section, where operations personnel have

voluntarily adopted good practices related to the

It may be advantageous not to repeat setpoint data

operation of the system, those practices should be

in the SDD in order to avoid the need to revise the

identified. For example, operations personnel may

SDD each time a setpoint specification is changed.

have assigned equipment nomenclatures and

When complete setpoint data is not provided as part

equipment labeling in accordance with a particular

of the SDD, a reference shall be provided to the

good practices guide.

separate document that contains the governing

setpoint information.

4.2.1 Initial Configuration (Pre-startup)

Internal controls and adjustments that are beyond

Some systems must be verified (for example, by

the domain of operators but within the domain of

system walkdown or status checks) to be in the

maintenance personnel should be identified. It is not

proper configuration for system operation prior to

necessary to identify all adjustments in the SDD;

those systems being started. When this is the case,

however, some setpoints will affect the limits of

the SDD should describe the pre-startup

performance of the equipment and should be made

configuration in general terms and provide a

known to the operators. For example, a backup

reference to the applicable procedure(s).

diesel generator may have an automatic trip on

overspeed or overcurrent. The preferred approach

Note: Previously, the use of footnotes

to these setpoints is to identify in the SDD those

and bibliographical information in an

setpoints that have a direct bearing on the limits of

Appendix has been discussed with

system performance and to present the nominal

regard to referring to system

values of those setpoints. The SDD should also

requirements and source documents.

provide a footnote reference to the maintenance

In a similar manner, footnotes should

procedures or other information that identifies all the

be used to refer to procedures for

internal setpoints and adjustments and provides the

system operations.

range of acceptable values.

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