**NRC INSPECTION MANUAL**
APHB

INSPECTION MANUAL CHAPTER 0609 APPENDIX F ATTACHMENT 2

DEGRADATION RATING GUIDANCE

0609, App F		Issue Date: 02/28/05

This appendix provides guidance on the assignment of a low or high degradation rating to various findings.  Degradation rating guidance is provided for most of the finding categories defined in Step 1.3.  This attachment does not provide a complete list of all potential types of degradation.  The inspector should use the criteria provided along with their professional judgement when assigning a degradation rating.  Depending on the type or location of degradation, a finding that could be categorized as low degradation per the guidance below, may be more problematic than anticipated by the guidance and should be considered a high degradation item at the discretion of the inspection.  

FIRE PREVENTION AND ADMINISTRATIVE CONTROLS PROGRAMS

This section provides guidance on assignment of a degradation rating to findings against the plant fire prevention program and other administrative controls (e.g., hot work permitting, transient combustible control programs, fire watches, etc.).

Findings against hot work permitting or fire watch provisions

Low degradations are warranted for inspection violations that will not have any significant effect on the likelihood that a fire might occur, or that a fire which does occur might not be promptly suppressed.  Examples of low degradations are as follows:

· Fire watch is not familiar with the facility at the location of the hot work and does not know the hazards of the work and procedures for sounding an alarm.

· The individual performing fire watch duties had improper training consisting of records showing a lack of required basic courses, refresher courses, and practice drills.

· Cases where a portable extinguisher of the proper type is nearby (within 30 ft. of unobstructed distance) even though watchers are inadequately equipped with fire extinguishers or other required equipment.  This includes cases where the proper portable extinguisher is nearby even though the relevant staff:

· Does not have a portable fire extinguisher on the watch when one is required by the hot work permit.

· Has only a discharged or inadequately charged extinguisher.

· Has only the wrong type of extinguisher for the fire hazards involved or conditions at the site (e.g., dry chemical in an area of high wind currents).

· Violations of the hot work permitting program, but all normally required fire prevention measures (e.g., a properly equipped and trained fire watch) are in place.

· Violations associated with hot work record keeping.

High degradation implies that early suppression (by the fire watch) is not available.  Examples of high degradations are as follows:

· Failures to implement a continuous fire watch in positions to observe all areas of vulnerability to a fire from the hot work operation.

· Failure to implement a fire watch at the site.

· Fire watch that is inadequately equipped with fire extinguishers or other required equipment. Inadequately equipped includes:

· Not having a portable fire extinguisher on the watch when one is required by the hot work permit.

· Having a discharged or inadequately charged extinguisher.

· Having the wrong type of extinguisher for the fire hazards involved or conditions at the site (e.g., dry chemical in an area of high wind currents).

· Fire watch failing to maintain any one of the following safe conditions[footnoteRef:1] during hot work operations: [1:  	Safe conditions were obtained from list of conditions in subsection 3-3.2 in NFPA 51B, “Standard for Fire Prevention during Welding, Cutting, and Other Hot Work,” 1999.] 

· Location is free of combustibles or that combustibles that cannot be moved are shielded against ignition.

· Hot work equipment to be used shall be in satisfactory operating condition and in good repair.

· Where combustible materials, such as paper clippings, wood shavings, or textile fibers are on the floor, the floor shall be swept clean for a radius of 35 ft.

· Combustible floors wet down, covered with damp sand or fire-resistant sheets for a 35 ft. radius.

· Fire watch failing to maintain fire watch for at least 1⁄2 hour after completion of hot work at all required observation points.

Note that fire watches compensating for temporary loss of detection/suppression and/or barriers primarily impact early fire detection/suppression time for ignition sources other than hot work and are treated in their respective places in this document.

Findings against the combustible controls program:

Another finding which potentially can affect fire ignition frequency is violation of transient combustible control limits, specifically those combustibles which could result in the ignition of a fire from existing sources of heat or electrical energy.  Transient combustibles of significance from a fire frequency standpoint are considered to be low flashpoint liquids (below 200 F) and self-igniting combustibles (oily rags).  In addition to combustibles, evidence of tobacco smoking or the existence of unauthorized heaters or heat sources can also be considered as adversely affecting compartment fire frequency.

Degradations ratings for findings against the combustible controls program are either low or high.  Examples of low and high degradations are as follows:

· Low degradation:

· Low flashpoint combustible liquids in quantities above those allowed by plant regulations but in approved containers.

· High degradation:

· A measurable quantity of a low flashpoint (200F) combustible liquid beyond the quantity allowed by the plant’s combustible loading controls, unattended, and not in an approved container.

· Unattended storage of self-heating materials such as oily rags not in an approved container.

· Evidence of recent smoking in a non-smoking area.

· An unapproved heater or heat source in the area.

FIXED FIRE PROTECTION SYSTEMS

Fire Detection:

· Low degradation:

· Less than 10% of smoke or heat detectors are degraded (nonfunctional, misplaced or missing), and functional detection is available near combustibles of concern. (Not applicable for areas with the potential for unconfined combustible or flammable liquid fire).

· Less than 25% detectors (heat or smoke) degraded (nonfunctional, misplaced or missing) in continuously occupied areas.

· High degradation:  System will fail to function.

· Power off.

· Detectors incompatible with system.

· Annunciators disabled, inaudible, or nonfunctional.

· Greater than 10% of smoke or heat detectors are degraded, and functional detection is available near combustibles of concern.

· Greater than 25% detectors degraded in continuously occupied areas.

Water Based Suppression:

· Low degradation:

· Less than 10% of heads are obstructed or non-functional, and

· There is a functional head within 10 ft. of combustibles of concern (or the maximum spacing allowed between sprinklers by NFPA 13), and

· System is nominally code compliant.

· High degradation:

· Non-functional system, or

· 10% or more of heads obstructed or non-functional, or

· Nearest head greater than 10 ft. from combustibles of concern (or the maximum spacing allowed between sprinklers by NFPA 13).

Gaseous Based Suppression:

Note:  Depending on the type of degradation, a finding that could be categorized as low degradation, may be more problematic and should be considered a high degradation item.  For example, a system with a hole that goes to the control room may be effective at extinguishing a fire but the system may cause control room evacuation or the donning of SCBAs by the control room operators and therefore should be considered high degradation.

· Low degradation:

· Hole in wall or floor with an area less than a single five-inch diameter penetration seal (Not to control room or remote shutdown area).

· Hole in ceiling up to 100 square inches (Not to control room or remote shutdown area).

· Time delay in system operation of exceeds design by 60 seconds or less.

· Discharge time exceeds allowable by less than 25%.

· Lack of test data.

· Test data shows concentration for 15 minutes (where 20 minutes are required for licensing basis).

· Achievable concentration is Halon 6% (where 7% is committed), or CO2 50% (where 60% is committed).

· High degradation:

· Power off.

· Inadequate agent to achieve required concentration for deep seated fires: Halon less than 5%; CO2 less than 40%.

· Design concentration achieved but cannot be maintained for sufficient time to ensure fire extinguishment.

· Fully blocked discharge head where gas cannot be released. (e.g., something tied around the head, or a head that is encased in something.)

· Hole in wall, floor, or ceiling greater than specified in the low degradation section.

FIRE CONFINEMENT AND LOCALIZED CABLE OR COMPONENT PROTECTION 

The approach to assigning a degradation rating to fire confinement and localized cable or component protection findings (see Step 1.3) is similar.  The analysis approach for quantifying these two finding categories is also similar.  These two categories cover findings of degradation to any passive fire barrier feature.  The guidance for assigning low or high degradation levels depends on the type of fire barrier being considered.  Examples are provided below to illustrate how an observed degradation is correlated to a degradation rating for each of several fire barrier types.  The analyst should select the fire barrier type that most closely matches the barrier being considered and continue the evaluation.

Low Density/High Density Elastomers (e.g., Silicone Foam):

· Low Degradation

· Less than 10% of required seal depth missing.

· Barriers/components not in preventative maintenance program.

· Poor quality foam cell structure (falls within Dow Corning’s #6 category) over <25% of the surface area.

· Through-cracks in seal material smaller than 1/8 inch that are less than 50% of the seal depth.

· High Degradation

· More than 10% of required seal depth is missing.

· Poor quality foam cell structure (falls within Dow Corning’s #6 category) of approximately >25% of the surface area.

· No tested or evaluated seal configuration and less than 11 inches of foam.

· Greater than 3/8-inch cracks in seal material extend to opposite face.

Sacrificial and Non-sacrificial Boards or Blankets (e.g., Mineral Wool or Ceramic Fiber):

· Low Degradation:

· < 10% depth of barrier material removed or never installed.

· Through-crack of equivalent diameter of 1⁄2 inch or less.

· Compression of material.

· High Degradation:

· 10% or more design depth of barrier material removed or never installed over 6 square inch area.

· Through-crack of equivalent diameter greater than 1⁄2 inch.

· Large metallic cross-section support or large cross-section cables entering wrap with less than 6 inches of wrap.

· Barrier configuration not tested or evaluated.

Unique/Boot Seals:

· Low Degradation:

· Severe tears, loose bands, open bands.

· Missing boot both sides.

· High Degradation

· Support missing.

· Less than 3 inches of seal.

· No ceramic fiber.

Concrete and Cement-based Grout or Penetration Seal Materials:

· Low Degradation:

· Through-cracks smaller than 1/8 inch in barrier that are not more than 50% of the required barrier thickness.

· 1/16 inch through barrier gaps or cracks.

· High Degradation:

· Greater than 30% of required concrete depth missing.

· Large surface area deformations (over 50% of surface) which would cause higher heat absorptions.

· Cracks determined to interfere with structural integrity.

· Thickness < 4.5 inches.

Doors:

· Low Degradation:

· Door gap not exceeding 25% of manufacturer's recommended specifications or up to 3/8 inch gap.

· Multiple holes in door on one side of a door surface with less than 1/8 inch opening.

· High Degradation:

· Multiple holes in door surface with greater than 1 inch opening.

· Door propped open or broken latch.

· Fire Door closure mechanism fails to secure the door shut.

Dampers:

· Low Degradation:

· Damper not in maintenance inspection program.

· Damper can close completely.

· High Degradation:

· Temperature of fusible link excessively high or fusible link improperly installed.

· Temperature of Electro-Thermal Link (ETL) is excessively high or ETL is improperly installed.

· Damper will not close completely.

· No damper at fire barrier in steel duct work.

· Damper is not rated to close against anticipated ventilation.

· Broken latch (where latch required for closure).

· No damper installed.

Unsealed Conduits:

· Low Degradation:

· Conduits smaller than 1 inch with 3 feet on each side of barrier.

· High Degradation:

· Conduits > 1 inch regardless of length on each side of barrier.

Water Curtains:

· Low Degradation:

· Less than 10% of heads obstructed or fouled, and no adjacent heads fouled.

· High Degradation:

· Greater than 10% of heads obstructed or fouled or two adjacent heads fouled or obstructed.

· System nonfunctional.

Radiant Energy Shields:

Note:  If the radiant energy shield is a ‘Rated’ barrier (Darmatt, Interram), use the appropriate barrier type from above.

· Low Degradation:

· Barrier completely obstructs line of sight between the target of interest and    potential fire sources that could affect redundant targets, and it is non-combustible.

· High Degradation:

· Barrier provides no more than partial line of sight obstruction between target of interest and potential fire sources that could affect redundant targets, or

· It is combustible.

POST-FIRE SAFE SHUTDOWN 

Post-fire safe shutdown (SSD) findings are related to degradations in operational aspects of post-fire SSD such as manual actions, analysis of associated circuits, analysis of required circuits, spurious operation, alternate shutdown, fire response procedures, the post-fire SSD analysis, etc.

The post-fire SSD finding category is not intended to cover findings against physical protection of the designated safe shutdown path such as passive fire barriers, fire detection, and fire suppression. Findings against physical protection features are covered under other finding categories.

Degradations ratings for findings against the licensee’s post-fire SSD program are either low or high.  Examples of low and high degradations are as follows:

· Low Degradation:

· Minor procedural deficiencies that are compensated by operator experience or familiarity.

· High Degradation:

· Procedural inconsistencies between EOPs and Fire SSD procedures.

· Equipment or tools not staged or located as specified by procedures.

· Operator training on fire SSD procedures incomplete.

· Feasibility to perform specified manual actions with available staff is not apparent.

· Post-fire SSD analysis is incomplete.

· Locations for actions required in SSD procedures are in environmentally challenging areas (e.g., low or high temperatures, high humidity).

· Plant conditions cannot be assessed or readily inferred from information available to the operators or as addressed in Fire SSD or EOP procedures.

· Plant design or component design severely impacts operator performance of SSD operations.

· Lack of alternate shutdown procedure.

Issue Date:  05/02/18	7	0609 App F Att 2

ATTACHMENT 1

Revision History for IMC 0609, Appendix F Attachment 2

Issue Date:  05/02/18	Att1-2	0609 App F Att 2