ML19291A958

IP 71111.06 Flood Protection Measures

ML19291A958
Person / Time
Issue date:	10/21/2020
From:	Cauffman C NRC/NRR/DRO/IRIB
To:
Cauffman C
Shared Package
ML19316A849, ML20233A512, ML20295A202	List:
References
CN 20-053, DC 19-029, DC 20-025
Download: ML19291A958 (9)

Text

Issue Date: 10/21/20 1

71111.06 NRC INSPECTION MANUAL IRIB INSPECTION PROCEDURE 71111 ATTACHMENT 06 FLOOD PROTECTION MEASURES Effective Date: 01/01/2021 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 Cable Degradation*

03.02 Annual 1 per site Not Required at Vogtle Units 3 & 4 1-2 Not Required at Vogtle Units 3 & 4

• Cable Degradation Sample is only required at sites with a history of cable degradation or failures due to submergence. Generic Letter 2007-01 responses indicate that the following sites experienced at least one in-service cable failure: Arkansas Nuclear One, Browns Ferry, Brunswick, Callaway, Columbia, D.C. Cook, Davis-Besse, Diablo Canyon, Farley, Fermi, Harris, Indian Point, Limerick, Monticello, North Anna, Palisades, Peach Bottom, Prairie Island, River Bend, Sequoyah, Turkey Point, Waterford, and Wolf Creek.

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.

Issue Date: 10/21/20 2

71111.06 71111.06-02 GENERAL GUIDANCE Review 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. Review licensee documentation that shows the design basis flood levels for areas containing safety-related equipment. Review condition reports and corrective actions for past flooding events.

Based on licensees flooding risk studies, select plant areas containing risk significant structures, systems, and components (SSCs) which are susceptible to flooding. For AP1000 units particular consideration should be given to inspecting feedwater lines, direct current (DC) electrical distribution and DC battery systems.

Select cable routing areas susceptible to submergence during flooding conditions, or where cables may be exposed to moisture from condensation and wetting, that contain multiple train or multiple risk-significant cables of a type susceptible to failure or degradation due to water submergence or moisture-induced damage. The inspection sample should be informed by the types of cables deployed at the site and their susceptibility to failure or degradation due to wetting, submergence, or moisture-induced damage as well as the effectiveness of the licensees programs for dewatering, monitoring, and/or performance testing of inaccessible or underground cables.

The following tables provide general inspection guidance for sample selection.

Cornerstone Inspection Objective Risk Priority Example 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

Issue Date: 10/21/20 3

71111.06 Cornerstone Inspection Objective Risk Priority Example 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 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 SAMPLES 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

a.

By observation/design reviews, including reviews of preventive maintenance (PM) activities, consider the following attributes. Give priority to those attributes which are risk significant for the site specific installation:

Issue Date: 10/21/20 4

71111.06

1.

Sealing of equipment below the design basis internal flood elevation, such as electrical conduits.

2.

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

3.

Adequacy of watertight doors between flood areas.

4.

Common drain system and sumps, including floor drain piping and check valves where credited for isolation of flood areas within plant buildings.

5.

Drain system has adequate protection (screens/covers) to prevent debris from disabling the drain system or components in the drain system.

6.

Operable sump pumps, level alarm and control circuits including maintenance and calibrations of flood protection equipment.

7.

Sources of potential internal 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.

8.

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

9.

Critical equipment such as equipment necessary to perform Emergency Operating Procedure (EOP) actions, is not below the maximum room water level calculated for flooding events as described in EOPs (as applicable).

10. Flood barrier impairment tracking and compensatory measures.

b.

For those areas where operator actions are credited, verify that the procedures such as abnormal or emergency procedures for coping with flooding can reasonably be used to achieve the desired actions, including whether the flooding event could limit or preclude the required operator actions.

03.02 Cable Degradation Verify that inaccessible power cables are adequately protected from environmental conditions and being monitored (through inspection and/or testing) in accordance with licensee programs. Verify that cable support structures are consistent with the design and any licensee commitments.

Specific Guidance This section is applicable only to sites with a history of underground cable failures or degradation due to condensation, wetting, submergence, or moisture-induced damage. 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 within the scope of the Maintenance Rule should be inspected when made reasonably accessible.

Issue Date: 10/21/20 5

71111.06 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, boroscopes/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 shall 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, verify by direct observation that the cables are not submerged in water.

For dry areas, assess 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 required to determine the extent of environmental degradation or impact on plant safety.

b.

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

Observe the condition of cable support structures. Verify the integrity of cables with degraded or missing support structures.

c.

If applicable, verify proper dewatering device (sump pump) operation and verify level alarm circuits are set appropriately to ensure that the cables will not be submerged. If dewatering devices are not installed, determine whether drainage is provided and is functioning for the cable routing areas selected. If neither dewatering devices nor drainage have been installed, verify that the operational environment of the cables is consistent with the manufacturers design specifications and qualification criteria.

d.

Inspections only need to be detailed enough to assess 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, verify that 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.

Review 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: 10/21/20 6

71111.06 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 Regulatory Guide 1.102, Flood Protection for 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.

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 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 02-12, Submerged Safety Related Electrical Cables IN 07-01, Recent Operating Experience Concerning Hydrostatic Barriers

Issue Date: 10/21/20 7

71111.06 Cross Reference of Generic Communications to IP 71111.06 and Inspection Resources:

https://drupal.nrc.gov/nrr/ope/33989 (nonpublic)

Operating Experience Gateway:

http://drupal.nrc.gov/nrr/ope (nonpublic)

IHSCodes and Standards:

https://drupal.nrc.gov/tech-lib/35748 (non-public)

NRC Technical Library:

https://drupal.nrc.gov/tech-lib (non-public)

END

Issue Date: 10/21/20 Att 1-1 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 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

Issue Date: 10/21/20 Att 1-2 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 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 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)