Clearance and Tagging Flashcards Preview

LOIT 2020 GOP phase > Clearance and Tagging > Flashcards

Flashcards in Clearance and Tagging Deck (19)
Loading flashcards...

State the specific conditions that do not require a clearance to be utilized.

  • Hazard is not complex.
  • isolation points are, at a minimum, within the worker's line of sight and close enough that the worker can prevent others from operating.
  • Work activity is performed by one individual or a two-person team when only one of the two is performing hands-on work. 
  • Activity performs minor servicing of operational equipment 
  • Minor servicing is performed on a periodic basis or in the course of the worker's routine activities.
  • All installed personnel safety guards and personnel safety interlocks remain intact and/or are properly used.
  • Work does not extend beyond the worker's shift, unless a proceduralized turnover process exists and the work will be conducted continuously.
  • Work is controlled by approved plant procedures or work instruction that identifies the hazard, the protective measures, and includes specific steps for accomplishing the activity. 
  • Work is a normal part of the worker's craft or assignment.
  • Worker is qualified to service the equipment.


Who has the authority to deviate from clearance requirements and when are they allowed to do so?

  • During a declared emergency condition, the Emergency Coordinator (EC) has the authority to deviate from clearance requirements.
  • Only if compliance would result in significant hazard to personnel or equipment, or increase radioactive release off-site.



State when double isolation criteria is required.  What requirements must be met when double isolation is necessary?

  • > 200°F or > 500 psig
  • Requires an open tell-tale vent or drain valve between the two isolations.
  • If double isolation boundaries are not practical or possible, additional measures should be used to provide adequate protection (removing flanged connections, or providing a vent or drain path where energy will be diverted to a safe location).
  • Lethal Chemical System (none at PVNGS)


When are Red Danger Tags used?

  • Used on the isolation boundaries and at least one vent/drain.
  • Can be on same component as a SOD tag.
  • Vent/drain not required to be tagged open if:
    • CTMT closure is compromised by the valve being opened. (Use a caution tag instead)
    • Contamination concerns (Use a caution tag instead)
    • Vent/drain valve is used for testing purposes (LLRT) (Use a caution tag instead)
    • Potential for re-accumulation of hazardous stored energy no longer exists after the initial drain/venting operations (PW drained during outage)
    • Only available vent or drain valve is going to be worked or removed


What are SOD tags used for?

Single Owner Danger (SOD) Tags:

  • Clearance used by a single work discipline to perform maintenance.
  • Prevents equipment operation during maintenance which could endanger personnel or damage equipment.
  • SOD Tag is equivalent to a Danger Tag.
  • Issued to a SOD Tag qualified Acceptor


When are Yellow Caution Tags used?

  • Used where no danger to personnel is involved. States specific info, which shall be understood before operating the equipment.



What are the MOV tagging requirements?

MOV tagging requirements:

  • Fluid system boundary: tag power supply and local operator.
  • Hand wheel NOT tagged when:
    • Only electrical MOV work is required
    • If manual seating of the MOV is not required, then MOVs inside containment do not require tags on the hand wheels during Modes 1 - 4 or when containment access is restricted.


What are the check valve tagging requirements?

Check valves:

  • NOT reliable as clearance boundaries.
  • If a check valve is used, tags will NOT be hung at the check valve(s)
  • Unit Operations Manager and Maintenance Department Leader authorization required.




What are the requirements to use a failed closed AOV as a boundary?

Fail Closed AOVs:

  • AOV is in the failed position before hanging the tag and closing the air isolation valve.
  • Power supply and/or air supply are isolated and tagged.

Hand wheels or local operators are tagged.


What are the requirements to use a failed open AOV as a boundary?

Fail Open AOVs:

  • Manually jacked closed with an installed “jacking” (manual) device.
  • Hand wheels or local operators are tagged.



What are the requirements to use 13.8kV and non class 4.16kV breakers as boundaries?

  • 13.8kV and non-class 4.16kV breakers
    • Lowered or disconnected position
    • Removed from the cubicle
    • NAN-S07 13.8kV breakers in “DISC/TEST” position as indicated by the position indicator on the front of the cabinet with the breaker TEST lever inside the cabinet in the vertical, stored position.
    • Breaker alignment checks which involve raising the breaker from its fully lowered position shall not be performed.


What are the requirements to use a class 4.16kV or 480Vac breaker as a boundary?

  • Class 4.16kV breakers
    • Lowered or disconnected position
      • Raised between 1 and 2” from the floor (seismic)
    • Removed from the cubicle
  • 480Vac load center breakers: Disconnected position or removed


What are the requirements to place clearance tags on fuses?

  • Load Center Fuses:
    • Remove fuse holder/block with fuses from the load center.
    • Rotate fuse holder/block and reinstall in the non-connected (visible) position in the load center.
    • Place tags on the fuse holder.
  • All Other Fuses:
    • Place tags as close to the fuse holder as practical or at a location obvious to anyone intending to replace the fuses.
    • Best location: directly on fuse holder (Not MCC control power fuses, which should be placed on the door).
    • Tags shall not be placed directly on the fuses.
  • Fuses that are removed should be individually bagged and identified (clearance/tag number, panel location, UNID)
  • If proper fuses cannot be located for reinstallation, submit a work request to ensure the proper fuses are installed.


What are the actions associated with a missing, worn or illegible tag?

Missing Tag Actions:

  • Immediately notify the MCR.
  • Responsible Supervisor ensures:
    • Work is stopped, establish positive control of the affected component, affected component is in the required condition.
    • Replace with new tag, document, use CV
    • Work Group(s) are notified that the tag has been rehung and stop work has been released.


Worn or illegible tag replacement:

  • Replace with new tag, document, use CV


What are the actions associated with a tag found unattached?

Unattached tag:

  • Leave the tag as found and report it to the MCR.
  • From an active clearance, Responsible Supervisor ensures:
    • Work is stopped, establish positive control of the affected component, affected component is in the required condition.
    • Tag is reattached using CV and documented
    • Work Group(s) are notified that the tag has been rehung and stop work has been released.
  • From a cancelled clearance, Responsible Supervisor ensures:
    • Tag is not being used as a credited tag.

Unattached tag is destroyed.



State the requirements to be a technical reviewer for clearances.

  • IV: checks clearance boundaries are adequate.
  • Licensed operator for Power Block Clearances (except for Ancillary Fire Protection Systems or Facilities Maintenance clearances).



Can PVGS work be performed under an ECC clearance?  

NO! a PVGS clearance is required in order to perform work.


How are zero energy checks performed on the following systems?

  • Electrical circuits
  • Pressurized systems
  • High temperature systems
  • Chemical Hazards

  • Electrical Circuits:
    • Check no voltage with voltmeter (preferred) or proximity tester.
      • MCC breakers checked with proximity probe by Ops (Check bus side, load side, then bus side)
    • Instrumentation in the failed position. Check breaker is disconnected. Attempt to start motors by normal means
  • Pressurized Systems
    • Check pressure is relieved at an open vent or drain (ensure it is not plugged) (preferred)
    • Use pressure instrumentation to check that the system is depressurized. Loosen a flange or valve bonnet. For saturated systems, check system temperature
  • High-Temperature Systems
    • Check temperature of the system at the work site
    • Use temperature instrumentation to check that the system is cooled. For a saturated system, check the system pressure
  • Chemical Hazards
    • Purge the system with inert fluid and sample by chemistry (preferred). 


Define the following tagging error levels and give examples of each:

Level 1

Level 2

Level 3

Level 4


  • Level 1 (Severe): Any issue leading to work being performed without protection. No barriers remaining.
    • Energy found unexpeced, in adequate boundary, red tagged component is manipulated or tag is willfully removed, 
  • Level 2 (Major): Problem with the Clearance is discovered after the tags are hung, but not accepted by Maintenance. Field issues potentially impact safety. One barrier remains, barrier is the willingness of the holder to sign on to the Clearance.
    • work performed without signing on to clearance, wrong compnent tagged but discovered before work commenced, errors found before work commences.
  • Level 3 (Minor): Problem with Clearance is discovered during the development and review process. Field Issues non-safety impacting. Two or more barriers remain.
  • Level 4 (Leading Indicator for Trending): Administrative related issues involving tagging process. Process efficiency or process improvements, not threats to process barriers