ML21075A363

IP 71111.06 Flood Protection Measures

ML21075A363
Person / Time
Issue date:	07/09/2021
From:	Aron Lewin NRC/NRR/DRO/IRIB
To:
Aron Lewin, NRR/DRO/IRIB, 415-2259
Shared Package
ML21089A040, ML21158A122	List: ML21075A363
References
CN 21-023, DC 21-006
Download: ML21075A363 (10)

Text

Issue Date: 07/09/21 1

71111.06 NRC INSPECTION MANUAL IRIB INSPECTION PROCEDURE 71111 ATTACHMENT 06 FLOOD PROTECTION MEASURES Effective Date: 01/01/2022 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 Sample Requirements Budgeted Range Sample Type Section(s) Frequency Sample Size Samples Hours Internal Flooding 03.01 Annual 2 per site 2-4 20 +/- 3 per site 10 +/- 2 at Vogtle Units 3 & 4 1 per site at Vogtle Units 3 & 4 1-2 at Vogtle Units 3 & 4 71111.06-01 INSPECTION OBJECTIVE 01.01 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 internal 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 flooding, including water intake facilities. Individual plant examinations (IPE) may contain additional information. 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. Based on licensees flooding risk studies, inspectors should select plant areas containing risk significant structures, systems, and components (SSCs) which are susceptible to flooding.

Issue Date: 07/09/21 2

71111.06 Generic communications which contain additional background information on flood protection measures are found in the References section of this Inspection Procedure.

The following tables provide general inspection guidance for sample selection.

Cornerstone Inspection Objective Risk Priority Examples Initiating Events Identify internal flooding which could cause initiating events Identify postulated submergence source and duration for selected cable routing area(s)

Potentials for common-cause failures Barriers between flood areas Unanalyzed sources of internal flooding Areas below the flood plain Cables whose failure due to moisture-induced damage could disable risk-significant equipment within the scope of the Maintenance Rule Adequate maintenance of expansion joints on high volume/low pressure systems Firewater sprinkler maintenance Unusual testing configurations for large volume water systems Cable rating and qualification is consistent with postulated submergence conditions Cables susceptible to submergence are de-energized during postulated submergence conditions Mitigating Systems Identify internal flooding events which could cause loss of safe-shutdown equipment Identify cable routing areas susceptible to submergence during flooding conditions (or where cables may be exposed to moisture from condensation and wetting)

Locations containing high volume/low pressure systems, such as firewater, service water and component cooling water, especially in areas containing flexible piping expansion joints.

Locations containing cables whose failure due to moisture-induced damage could disable risk-significant equipment within the scope of the Maintenance Rule Water-tight doors, sump pumps, and alarms Adequate sealing of safe-shutdown electrical equipment below the flood line Check valves in open drain systems common to different flood areas Cable rating and qualification is consistent with postulated submergence conditions Cables susceptible to submergence are de-energized during postulated submergence conditions

Issue Date: 07/09/21 3

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 Internal Flooding Walkdown a selected area(s) or room(s) susceptible to internal flooding. Verify that internal flooding sources are analyzed, designated flooding barriers are functional and appropriate to protect critical mitigating systems and equipment, and operator coping actions can reasonably be completed.

Specific Guidance Inspectors should conduct observation/design reviews, 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 internal flood elevation, such as electrical conduits.

Sealing of equipment floor plugs, holes or penetrations in floors and walls between flood areas.

Adequacy of watertight doors between flood areas.

Condition and availability of temporary or removable flood barriers (i.e.,

gaskets).

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.

3.

Other Considerations Sources of potential internal flooding that are not analyzed or not adequately maintained, for example failure of flexible piping expansion

Issue Date: 07/09/21 4

71111.06 joints, failure of fire protection system sprinklers, roof leaks, rest room backups, and failure of service water lines.

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). 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.

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 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 inaccessible power cables can be found in Attachment 1.

71111.06-04 REFERENCES IMC 2515, Appendix A, Risk-Informed Baseline Inspection Program IMC 2515, Appendix D, Plant Status IMC 0308, Attachment 2, Technical Basis for Inspection Program IP 71152, Problem Identification and Resolution 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.

Information Notice (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.

Issue Date: 07/09/21 5

71111.06 IN 94-27, Facility Operating Concerns Resulting from Local Area Flooding, March 31, 1994.

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.

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.

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

IN 07-01, Recent Operating Experience Concerning Hydrostatic Barriers IN 10-26, Submerged Electrical Cables IN 16-11, Potential for Material Handling Events to Cause Internal Flooding END

Issue Date: 07/09/21 Att1-1 71111.06 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.

Issue Date: 07/09/21 Att1-2 71111.06

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.

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: 07/09/21 Att2-1 71111.06 Revision History for IP 71111.06 Commitment Tracking Number Accession Number Issue Date Change Notice Description of Change Description of Training Required and Completion Date Comment Resolution and Closed Feedback Form Accession Number (Pre-Decisional, Non-Public Information)

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

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

N/A N/A N/A ML063470601 01/25/07 CN-07-003 IP 71111.06 has been revised to address feedback form 71111.06-889 to update procedure based on 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 ML063470279 N/A ML072960248 01/31/08 CN-08-005 IP 71111.06 has been revised to address the 2007 ROP realignment, shifting external flooding review to IP 71111.01, and to correct typographic errors.

N/A ML073520328 N/A ML082120529 08/19/08 CN 08-024 IP 71111.06 has been revised to clearly state that an inspection sample is one area. This addresses feedback form 71111.06-1267.

N/A N/A

Issue Date: 07/09/21 Att2-2 71111.06 Commitment Tracking Number Accession Number Issue Date Change Notice Description of Change Description of Training Required and Completion Date Comment Resolution and Closed Feedback Form Accession Number (Pre-Decisional, Non-Public Information)

N/A ML083170651 06/25/09 CN-09-016 IP 71111.06 has been revised to address feedback form 71111.06-1294. A revision has also been made 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.

N/A ML090700224 N/A ML11244A012 10/28/11 CN-11-025 IP 71111.06 has been revised to include guidance on age-related degradation and license renewal aging management programs.

N/A ML11297A116 N/A ML15140A133 11/25/15 CN-15-027 IP 71111.06 has been revised to address feedback forms 71111.06-1768 and 71111.06-1863 and expand on guidance related to inspection of cable routing areas susceptible to flooding or where cables may be exposed to moisture from condensation or wetting.

N/A ML15141A040 71111.06-1768 ML15141A060 71111.06-1863 ML15141A072 N/A ML19291A958 10/21/20 CN 20-053 Major revision. Relocated optional requirements to the guidance section to better align with IMC 2515, Section 8.04, sample completion requirements.

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

None ML19316B052 (2019)

ML20233A518 (2020)

Issue Date: 07/09/21 Att2-3 71111.06 Commitment Tracking Number Accession Number Issue Date Change Notice Description of Change Description of Training Required and Completion Date Comment Resolution and Closed Feedback Form Accession Number (Pre-Decisional, Non-Public Information)

N/A ML21075A363 07/09/21 CN 21-023 Revisions include: 1) Address Feedback Form 71111.06-2434. Required cable degradation sample deleted. Oversight of cable degradation may be performed if desired as part of an Internal Flooding sample. 2) Clarified requirements vs guidance per OIG-16-A-12 (ML16097A515).

3) Formatting reflects current IMC 0040 (ML19352E640) requirements.

None ML21092A029 ML21075A362 71111.06-2434