Safety Limits, Limiting Control Settings, and Limiting Conditions for Operation

DOE-STD -3009-94

5.5.X.1

Safety Limits, Limiting Control Settings, and Limiting

Conditions for Operation

This section provides the basis and identifies information sufficient to derive

SLs, LCSs, and LCOs to support the facility TSR documentation required by

10 CFR 830.205. SLs, if used, are reserved for a small set of extremely

significant features that prevent potentially major offsite impact. LCSs are

developed for any SL that is protected by an automatic device with setpoints.

LCSs/LCOs act to keep normal operating conditions below the SLs and are

developed for each SL identified, thereby providing a margin of safety. Most

LCOs are assigned without an accompanying SL.

Generally SLs are applicable only for protection of passive barriers as close to

the accident source as possible whose failure, due to the occurrence of a

specific event, will result in exceeding the Evaluation Guideline. Mitigation of

releases is generally not amenable to useful definition of SLs. For example, a

ventilation system directing airflow through HEPA filters to keep offsite

radio logical dose below the Evaluation Guideline during an accident is

mitigative and is more appropriately covered by a LCO. Temporary loss of its

function during normal operations does not initiate a significant hazardous

material release. An LCO on the sys tem would identify the specific responses

necessary to compensate for the loss of safety function. Control of the

ventilation system via a SL would be academic for preventing accidents that

the ventilation system only mitigates. In contrast, consider a t ank that acts as a

barrier preventing an uncontrolled release of hazardous material that could

exceed the Evaluation Guideline without ventilation mitigation. If that tank

could experience a hydrogen explosion and rupture, then the tank hydrogen

concentration may warrant coverage by a SL.

5.5.X.2

Surveillance Requirements

This section provides the basis and identifies information necessary to derive

Surveillance Requirements that address testing, calibration, or inspection

requirements to maintain operatio n of the facility within SLs, LCSs, and

LCOs.

5.5.X.3

Administrative Controls

This section provides the basis and identifies information necessary to derive

TSR administrative controls. This section is the only applicable section for

those features listed in Section 5.3, "TSR Coverage," that are provided with

only TSR administrative controls. The rationale for assigning TSR

administrative controls need to be clearly and briefly stated.

A special type of TSR administrative control is that covering a safety

management program. The administrative controls section of the TSR

document will contain commitments to establish, maintain, and implement

these programs at the facility and, as appropriate, facility staffing requirements.

Specific administrative contro ls, when designated, provide specific actions

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