ML22066B334

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IP 71111.06 Flood Protection Measures
ML22066B334
Person / Time
Issue date: 08/01/2022
From: Aron Lewin
NRC/NRR/DRO/IRIB
To:
Aron Lewin, NRR/DRO/IRIB, 415-2259
Shared Package
ML22068A181 List:
References
CN 22-015
Download: ML22066B334 (10)
v • d • e


Text

NRC INSPECTION MANUAL IRIB

INSPECTION PROCEDURE 71111 ATTACHMENT 06

FLOOD PROTECTION MEASURES

Effective Date: January 1, 2023

PROGRAM APPLICABILITY: IMC 2515 A

CORNERSTONES: Initiating Events Mitigating Systems

INSPECTION BASES: See Inspection Manual Chapter (IMC) 0308, Attachment 2

SAMPLE REQUIREMENTS:

Sample Requirements Minimum Baseline Completion Budgeted Range Sample Requirements Sample Type Section(s) Frequency Sample Size Samples Hours Flooding 03.01 Annual 1 per site 1 to 3 per 6 to 18 per site site

71111.06- 01 INSPECTION OBJECTIVE

This inspection will focus on verifying that the licensees flooding mitigation plans and equipment are consistent with the licensees design requirements and the risk analysis assumptions.

71111.06 -02 GENERAL GUIDANCE

Inspectors should review: 1) the final safety analysis report (FSAR) and seek input from Senior Reactor Analysts regarding site-specific flood risk analysis documents (e.g., licensee events probabilistic risk assessment (PRA), and external significance determination process ( SDP) notebooks, as applicable) to identify those areas that are most likely to be affected by internal and external flooding, including water intake facilities. Individual plant examinations (IPE) may contain additional information. Consider seasonal susceptibilities to floods caused by hurricanes, heavy rains, and flash floods. 2) licensee documentation that shows the design basis flood levels for areas containing safety-related equipment. 3) condition reports and corrective actions for past flooding events. Consider weather-related information gathered during plant status reviews or from external news sources. Based on licensees flooding risk studies, inspectors should select plant areas containing risk-significant structures, systems, and components (SSCs) which are susceptible to flooding. As a minimum, one flooding sample associated with internal flooding should be performed. Based on a site-specific risk analysis and weather-related events, an additional flooding sample associated with external flooding may be

Issue Date: 08/01/22 1 71111.06 performed. Generic communications which contain additional background information on flood protection measures are found in the References section of this Inspection Procedure.

The following table provides general inspection guidance for sample selection.

Cornerstone Inspection Objective Risk Priority Examples Initiating Identify flooding Potentials for common-Adequate maintenance of Events which could cause cause failures expansion joints on high initiating events volume/low pressure Barriers between flood systems areas Firewater sprinkler Unanalyzed sources of maintenance flooding Unusual testing configurations for large volume water systems Identify postulated submergence Areas below the flood Cable rating and source and duration plain qualification is consistent for selected cable with postulated routing area(s) Cables whose failure due submergence conditions to moisture-induced Cables susceptible to damage could disable submergence are de-risk-significant equipment energized during postulated within the scope of the submergence conditions Maintenance Rule Mitigating Identify flooding Locations containing high Water-tight doors, Systems events which could volume/low pressure sump pumps, and alarms cause loss of safe-systems, such as shutdown equipment firewater, service water Adequate sealing of safe-and component cooling shutdown electrical water, especially in areas equipment below the flood containing flexible piping line expansion joints.

Check valves in open drain systems common to different flood areas Identify cable routing areas susceptible to Locations containing Cable rating and submergence during cables whose failure due qualification is consistent flooding conditions to moisture-induced with postulated (or where cables damage could disable submergence conditions may be exposed to risk-significant equipment moisture from within the scope of the Cables susceptible to condensation and Maintenance Rule submergence are de-wetting) energized during postulated submergence conditions

Issue Date: 08/01/22 2 71111.06 For each sample, routine review of problem identification and resolution activities should be conducted using IP 71152, Problem Identification and Resolution.

71111.06- 03 INSPECTION REQUIREMENTS

03.01 Flooding.

Verify that flooding sources are analyzed, designated flooding barriers and equipment are functional and appropriate to protect critical mitigating systems and equipment, and operator coping actions can reasonably be completed.

Walkdown a selected area(s) or room(s) susceptible to flooding.

Specific Guidance

Inspectors should conduct observation/design review s, including reviews of preventive maintenance (PM) activities, and consider the following attributes, giving priority to those attributes which are risk significant for the site -specific installation:

1. Flood Seals and Barriers
  • Sealing of equipment below the design basis flood elevation, such as electrical conduits. Consider if the service life of seals is consistent with the manufacturers recommendations or that a documented engineering evaluation provides justification for service life beyond the manufacturers recommendations.
  • Sealing of equipment floor plugs, holes or penetrations in floors and walls between flood areas. Consider if procedures or programs to monitor for degraded conditions have been implemented.
  • Adequacy of watertight doors between flood areas. Consider alignment of dog ears, adequacy of seals, and wear or impact damage on critical parts of the doors.
  • Condition and availability of temporary or removable flood barriers (i.e., gaskets, sandbags, or sand baskets).
  • Flood barrier impairment tracking and compensatory measures.
2. Drainage Systems and Sumps
  • Common drain system and sumps, including floor drain piping and check valves where credited for isolation of flood areas within plant buildings.
  • Drain system has adequate protection (screens/covers) to prevent debris from disabling the drain system or components in the drain system.
  • Operable sump pumps, level alarm and control circuits including maintenance and calibrations of flood protection equipment.

Issue Date: 08/01/22 3 71111.06

  • Anti-siphon features, such as check values and vacuum breaks, used to prevent external flooding ingress.
  • Perimeter drain systems that minimize the egress of water to safety-related plant areas are functional (external flooding).
3. Operator Actions
  • For those areas where operator actions are credited, inspectors should consider if such procedures can reasonably be used to achieve the desired actions, including whether the flooding event could limit or preclude the required operator actions.
  • Critical equipment, such as equipment necessary to perform Abnormal Operating Procedure (AOP) or Emergency Operating Procedure (EOP) actions, is not below the maximum room water level calculated for flooding events as described in AOPs or EOPs (as applicable).
  • Water levels and associated effects (e.g., waves, run-up, or debris) will not impair support functions or the performance of necessary actions.
  • Procedures or activities include a discussion on warning time and notification that a flood is imminent (external flooding).
  • Procedures or activities can be executed as specified and within the required timeframe (e.g., closure of water-tight doors achievable in the available timeframe).
  • Presence of other factors (e.g., equipment availability and staffing) will not prevent implementation of required actions.
  • Proposed actions will not result in consequences that adversely affect other required safety or security functions (e.g., impairing required cooling functions).
  • Procedures include a discussion on how long the site could be flooded and appropriate considerations for the duration of the flood (e.g., availability of required consumables) (external flooding).
  • Consider observing flood mitigation drills and tabletops when possible.
4. Other Considerations
  • Sources of potential flooding that are not analyzed or not adequately maintained, for example failure of flexible piping expansion joints, failure of fire protection system sprinklers, roof leaks, rest room backups, and failure of service water lines. For external flooding, are process es in place for incorporating or assimilating information from external sources (e.g., the National Oceanic and Atmospheric Administration or Army Corp of Engineers).
  • Inaccessible power cables ( e.g., those found in underground bunkers/manholes, cable trenches, cable troughs, above ground and underground duct banks, underground vaults, etc.) are adequately protected from environmental

Issue Date: 08/01/22 4 71111.06 conditions and being monitored (through inspection and/or testing) in accordance with licensee programs. Cable support structures are consistent with the design and any licensee commitments. Additional guidance on i naccessible power cables can be found in Attachment 1.

71111.06- 04 REFERENCES

10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants

Circular 78-06, Potential Common Mode Flooding of ECCS Equipment Rooms at BWR Facilities, May 31, 1978

Generic Letter 2007- 01, Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients

IMC 0308, Attachment 2, Technical Basis for Inspection Program

IMC 2515, Appendix A, Risk -Informed Baseline Inspection Program

IMC 2515, Appendix D, Plant Status

IN 02-12, Submerged Safety Related Electrical Cables

IN 03-08, Potential Flooding Through Unsealed Concrete Floor Cracks

IN 05-11, Internal Flooding/Spray -Down of Safety-Related Equipment Due to Unsealed Equipment Hatch Floor Plugs and/or Blocked Floor Drains, May 6, 2005

IN 05-30, "Safe Shutdown Potentially Challenged by Unanalyzed Internal Flooding Events and Inadequate Design, November 07, 2005

IN 07-01, Recent Operating Experience Concerning Hydrostatic Barriers

IN 10-26, Submer ged Electrical Cables

IN 16-11, P otential for Material Handling Events to Cause Internal Flooding

IN 83-44, Potential Damage to Redundant Safety Equipment as a Result of Backflow Through the Equipment and Floor Drain System, July 1, 1983

IN 83-44s1, Potential Damage to Redundant Safety Equipment as a Result of Backflow Through the Equipment and Floor Drain System, August 30, 1990

IN 87-49, Deficiencies in Outside Containment Flooding Protection, October 9, 1987

IN 88-60, "Inadequate Design and Installation of Watertight Penetration Seals," August 11, 1988

IN 92-69, Water Leakage from Yard Area Through Conduits into Buildings, September 22, 1992

IN 94-27, Facility Operating Concerns Resulting from Local Area Flooding, March 31, 1994

Issue Date: 08/01/22 5 71111.06 IN 98-31, Fire Protection System Design Deficiencies and Common-Mode Flooding of Emergency Core Cooling System Rooms at Washington Nuclear Project Unit 2, August 18, 1998

IP 71152, Problem Identification and Resolution

END

Issue Date: 08/01/22 6 71111.06 Attachment 1: Inaccessible Power Cables

Inaccessible power cable routing areas or locations (e.g., underground bunkers/manholes, cable trenches, cable troughs, above ground and underground duct banks, underground vaults, cable entry points into buildings below ground level, etc.) that contain cables whose failure could disable risk-significant equipment or multiple trains within the scope of the Maintenance Rule should be inspected when made reasonably accessible. Cable failures or degradation can occur due to condensation, wetting, submergence, or moisture-induced damage.

NOTE: Inspection efforts should not create undue burden on the licensee. The intent is to coordinate access to the applicable areas (cable trenches, cable troughs, underground duct banks, underground vaults, etc.) in advance in order to minimize the impact on licensees. For those plants within the period of extended operation, bunkers/manholes within the scope of license renewal are also subject to inspections as part of the licensees aging management program for inaccessible power cables. Whenever possible, inspection activities should be arranged such that NRC inspectors accompany plant personnel on the licensees periodic inspections. If necessary, borescopes / cameras can be used to inspect cable routing areas in lieu of direct physical access. If sump pumps have been installed, verification that the sump pumps are functioning (e.g., level indication or alarm) is an acceptable alternative to direct observation if the affected areas are not periodically opened for direct inspection (provided that power is available to these systems during the postulated flooding events). However, these areas should be made a priority for inspection when availability exists. Additional guidance on reviews/tours of normally inaccessible areas is provided in Inspection Manual Chapter 2515, Appendix D, Plant Status.

a. When feasible, consider direct observation that the cables are not submerged in water.

For dry areas, consider current state for evidence (water marks on wall, debris in cable trays, etc.) which may indicate previous submergence. If the cables are submerged, or there is evidence of previous submergence, further evaluation in consultation with Regional or NRR subject matter experts may be considered to determine the extent of environmental degradation or impact on plant safety.

b. When feasible, consider by direct observation that cables and/or splices appear intact.

Consider observation of the condition of cable support structures. Consider the integrity of cables with degraded or missing support structures.

c. If applicable, consider proper dewatering device (sump pump) operation and level alarm circuits are set appropriately to ensure that the cables will not be submerged. If dewatering devices are not installed, consider whether drainage is provided and is functioning for the cable routing areas selected. If neither dewatering devices nor drainage have been installed, consider if the operational environment of the cables is consistent with the manufacturers design specifications and qualification criteria.
d. Inspections may only consider the condition of the cables located within the cable routing areas. If issues are identified, or questions arise during the inspection, inspectors should contact the Regional or NRR technical specialists for guidance and/or assistance in the determination of the acceptability or unacceptability of any issues.
e. (For those plants within the period of extended operation). If moisture is identified, consider if the licensee takes action to keep the cables dry and assess cable degradation in accordance with the licensees aging management program for inaccessible power cables.

Issue Date: 08/01/22 Att1-1 71111.06

f. Consider the licensees inspection, testing and monitoring programs to detect the degradation of inaccessible or underground power cables that support emergency diesel generators, offsite power, emergency service water, service water, component cooling water and other systems that are within the scope of 10 CFR 50.65 (the Maintenance Rule).

Issue Date: 08/01/22 Att1-2 71111.06 Attachment 2: Revision History for IP 71111.06

Commitment Accession Description of Change Description of Comment Resolution and Tracking Number Training Required Closed Feedback Form Number Issue Date and Completion Accession Number Change Notice Date (Pre-Decisional, Non-Public Information)

N/A 04/03/00 71111.06 has been issued to provide the minimum N/A N/A CN- 00- 003 inspection oversight for determining the safety performance of operating nuclear power reactors.

N/A 01/17/02 71111.06 has been issued to provide the minimum N/A N/A CN- 02- 001 inspection oversight for determining the safety performance of operating nuclear power reactors.

N/A ML063470601 IP 71111.06 has been revised to address feedback N/A ML063470279 01/25/07 form 71111.06-889 to update procedure based on CN- 07- 003 inspection and operating experience. Also, the Level of Effort and Inspection Basis sections were changed to give the flexibility to select either internal or external samples based on inspectors' discretion.

N/A ML072960248 IP 71111.06 has been revised to address the 2007 N/A ML073520328 01/31/08 ROP realignment, shifting external flooding review to CN-08-005 IP 71111.01, and to correct typographic errors.

N/A ML082120529 IP 71111.06 has been revised to clearly state that an N/A N/A 08/19/08 inspection sample is one area. This addresses CN 08-024 feedback form 71111.06-1267.

N/A ML083170651 IP 71111.06 has been revised to address feedback N/A ML090700224 06/25/09 form 71111.06-1294. A revision has also been made CN- 09- 016 to the inspection requirements associated with underground cables. This inspection was changed from an optional sample to a mandatory sample as a result of information gathered from GL 2007-01.

Issue Date: 08/01/22 Att2-1 71111.06 Commitment Accession Description of Change Description of Comment Resolution and Tracking Number Training Required Closed Feedback Form Number Issue Date and Completion Accession Number Change Notice Date (Pre-Decisional, Non-Public Information)

N/A ML11244A012 IP 71111.06 has been revised to include guidance N/A ML11297A116 10/28/11 on age-related degradation and license renewal CN-11-025 aging management programs.

N/A ML15140A133 IP 71111.06 has been revised to address feedback N/A ML15141A040 11/25/15 forms 71111.06-1768 and 71111.06-1863 and 71111.06-1768 CN-15- 027 expand on guidance related to inspection of cable ML15141A060 routing areas susceptible to flooding or where cables 71111.06-1863 may be exposed to moisture from condensation or ML15141A072 wetting.

N/A ML19291A958 Major revision. Relocated optional requirements to None ML19316B052 (2019) 10/21/20 the guidance section to better align with IMC 2515, CN 20- 053 Section 8.04, sample completion requirements. ML20233A518 (2020)

Added AP1000 sample requirements. Five year periodic review. Reformatted to conform to IMC 0040.

N/A ML21075A363 Revisions include: 1) Address Feedback Form None ML21092A029 07/09/21 71111.06-2434. Required cable degradation sample CN 21-023 deleted. Oversight of cable degradation may be ML21075A362 performed if desired as part of an Internal Flooding 71111.06-2434 sample. 2) Clarified requirements vs guidance per OIG-16-A-12 (ML16097A515). 3) Formatting reflects current IMC 0040 (ML19352E640) requirements.

N/A ML22066B334 Samples revised per NRR direction using None N/A Issued as final.

08/01/22 Enclosure 2 (ML19070A040) of SECY 0067 CN 22-015 (ML19070A050) as guidance.

Issue Date: 08/01/22 Att2-2 71111.06

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