System Control Features

DOE-STD-3024-98

installed remotely on a nearby control panel, or

System design characteristics such as preferred

installed remotely in a central location.

failure modes or "fail-safe" positions or states shall

be discussed. This section should discuss other

Instrumentation either directly subject to TSRs or

known failure modes of the system and their affects

that provide information to verify compliance with

on the system and the facility. (The associated

TSRs shall be identified as such.

compensatory measures and recovery action are

addressed in Section 4.2.4.) References should be

4.1.6.2

Control Capability and Locations

provided to applicable engineering studies or failure

modes and effects analyses (FMEAs), if such

System, equipment, and component manual

reports are known to exist. Features in the system

operational controls shall be described. The

design that make the system testable shall be

locations of these controls and the actions caused by

described.

actuating these controls shall be identified clearly.

Where the system includes redundant subsystems or

4.1.6.3

Automatic and Manual Actions

components, the SDD description shall identify

The SDD shall describe the conditions under which

these redundant features. The SDD shall describe

important features are to be activated and whether

the capacity and degree of redundancy provided.

For example, a particular design might require the

these features are activated automatically or

operation of two exhaust fans at all times, but four

manually. Where automatic or manual controls are

specifically associated with specific instrumentation,

fans are provided in the design. If two fans are

the instrumentation and control actions should be

necessary, each might be a 50% capacity fan, with

correlated in the SDD. For example, the control

two additional 50% fans in standby ready for

action might be taken only upon reaching a

operation. Also, discuss independence of the

particular value as detected by a specific

redundant features. Any technical limitations on the

instrumentation channel or displayed by a specific

use of the redundant features shall also be described.

For example, while four fans are available for

indicating device, or an indicator might provide

operation, a maximum of only three fans is allowed

feedback of system response that must be closely

monitored

to be operated at one time to avoid excessive flow

rates.

Where alarms are provided that are intended to

trigger manual safety actions, the SDD shall provide

4.1.6 System Control Features

an overview of the operator actions that are to be

taken and refer to the corresponding operating

This section shall describe the indication, alarm, and

procedures that govern the operator responses to the

control features of the system that are used to

alarms. Alarms for non-safety actions (such as

operate the system and monitor its performance.

those that identify the need for operational

Control logic diagrams should be provided.

adjustments or fine tuning) should be described

similarly. Here again, footnotes should be used to

4.1.6.1

System Monitoring

point to the particular procedure in the appropriate

appendix to the SDD. This discussion should be

The instrumentation, indicators, alarms, and other

coordinated with the discussion in Section 4.2

information provided to operations personnel,

"Operations" related to off-normal operations in a

remote and local, to allow assessment of system

manner that avoids unnecessary overlap and

status and performance shall be described, including

repetition.

types, ranges, and accuracies. This may include

indicators, recorders, status lights, CRT displayed

4.1.6.4

Setpoints and Ranges

information, computer printouts, and information

automatically stored on disks or tapes. The

This section of the SDD shall identify setpoints

locations of these items should be identified clearly,

associated with the system (including pre-trip

such as being mounted directly on the equipment,

Page 18