NRC INSPECTION MANUAL	IRIB

INSPECTION PROCEDURE 71111 ATTACHMENT 01

# ADVERSE WEATHER PROTECTION

# 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:

* Prior to the onset of seasonal extreme weather** When impending severe weather is anticipated

# 71111.01-01	INSPECTION OBJECTIVES

01.01	To verify that mitigating systems are not adversely impacted or challenged by adverse weather conditions.

01.02	To verify that adverse weather-related problems that could cause initiating events or impact the availability and functional capability of mitigating systems are identified and resolved.

# 71111.01-02	GENERAL GUIDANCE

This inspection procedure should be used to inspect weather-related risks (e.g., high winds, hurricanes, torrential rains, electrical storms, tornadoes, extreme high or low temperatures) adversely affecting the ultimate heat sink (e.g., debris, ice blockages, frazil ice, sea grass, fish, etc.), offsite power systems, and alternate AC power sources. When practical, the inspection should be performed prior to the onset of adverse weather conditions at the site.

For each sample, routine review of problem identification and resolution activities should be conducted using IP 71152, “Problem Identification and Resolution.”

Sample Considerations

# 71111.01-03	INSPECTION SAMPLES

## 03.01	Seasonal Extreme Weather.

Verify the adequacy of the licensee seasonal readiness prior to the onset of seasonal extreme weather conditions.

Specific Guidance

a. Consider review of seasonal extreme weather preparation procedures (e.g., extreme high temperatures, extreme low temperatures, or hurricane season preparations).

b. Consider if weather-related equipment deficiencies identified during the previous year have been corrected prior to the onset of seasonal extremes.

c. Consider implementation of the seasonal extreme weather preparation procedures and compensatory measures for the seasonal extremes. Consider accessibility of controls, indications, and equipment.

d. For summer readiness, consider review of the material condition of the plant’s offsite AC power systems and onsite alternate AC power systems, including the switchyard and transformers. Consider review of outstanding work orders.

e. Consider selection of two to four risk-significant systems that are required to be protected from the seasonal extreme weather conditions. Consider review of the updated final safety analysis report (UFSAR), technical specifications, and plant documents associated with these systems and then consider assessing the following:

1. The selected systems or components will remain operable/functional when challenged by seasonal extreme weather conditions.

2. As applicable, plant features and procedures for operation and continued availability of the ultimate heat sink (i.e., river, lake, and ocean) during seasonal extreme weather conditions are appropriate. Consider the licensee’s plans to address the ramifications of potentially lasting effects of seasonal extreme weather conditions (e.g., drought, flood, extreme cold weather). As applicable, the ultimate heat sink maximum and minimum temperature limits, as specified in the technical specifications and/or UFSAR, are appropriately and conservatively translated into system operating procedures, alarm response procedures, operability guidance, and design basis calculations. During extended periods of high or low temperatures, the vital plant areas (e.g., Emergency Core Cooling System pump rooms, containment or drywell, electrical switchgear rooms, and diesel rooms) cooled directly/indirectly by process mediums affected by external environmental conditions are adequately maintained within design basis limits. Independently verify by walkdowns where possible. This includes consideration for instrument accuracy to support conservative and timely operator action to ensure adequate margin to design basis limits.

3. As applicable, cold weather protection features, such as heat tracing, space heaters, and weatherized enclosures are monitored sufficiently to ensure that they support operability/functionality of the system, structure, or component (SSC) they protect. This includes instrument controller and alarm calibration programs, as necessary,

to support the cold weather protection function. As appropriate, consider performing a walkdown to verify the physical condition of weather protection features.

4. Operator actions defined in the licensee’s seasonal extreme weather procedure maintain readiness of essential systems. Minimum / adequate operator staffing is specified.

5. Systems and/or components required for a reactor shutdown and affected by the seasonal extreme weather conditions are available to perform their reactor shutdown functions under assumed conditions.

6. As applicable, the licensee can demonstrate through testing or analysis that diesel fuel oil Cloud Point[footnoteRef:2] specifications are acceptable for operability of diesel generator systems with above ground fuel storage tanks (e.g., emergency diesel generators, station blackout diesel generators, security diesels, fire protection diesel generators, etc.) during extreme cold weather conditions. [2:  Cloud Point defines the temperature at which a cloud or haze of wax crystals appears in the oil under prescribed test conditions, which generally relates to the temperature at which wax crystals begin to precipitate from the oil in use. [Source: ASTM D-975]] 

## 03.02	Impending Severe Weather.

Verify the adequacy of the overall preparations to protect risk-significant systems from impending severe weather.

Specific Guidance

a. Consider evaluating implementation of appropriate severe weather preparation procedures and compensatory measures for the severe weather that is currently impacting or is expected to imminently impact the facility, its operations, or the ability of personnel to respond to an emergency. Consider review of the licensee’s plans to address the ramifications of potentially lasting effects that may result from the severe weather conditions (e.g., drought, flood).

b. Consider if severe weather procedure operator actions maintain the readiness of essential systems. Verify that minimum/adequate operator staffing is specified. Consider accessibility of controls, indications, and equipment.

c. Consider if required surveillances are current, or are scheduled and completed, if practical, before anticipated severe weather conditions develop.

d. Consider the status of safety related equipment and to ensure inoperable equipment does not prompt a Notice of Enforcement Discretion (NOED) request. Note: The Enforcement Policy provides for the exercise of enforcement discretion under circumstances in which maintaining the stability and reliability of the electrical power supply system is consistent with protecting the public health and safety. Weather-related NOED requests usually involve a missed surveillance, an improperly scheduled surveillance, or inoperable equipment.

e. Consider review of plant modifications, maintenance activities (i.e., temporary hazard barrier removal), new evolutions, procedure revisions, or operator workarounds implemented to address periods of adverse weather that can inadvertently affect maintenance rule systems and SSCs. Consider if the licensee has assessed and managed these challenges to safe plant operation. Further follow-up may be appropriate using IP 71111.12, “Maintenance Effectiveness”; IP 71111.13, “Maintenance Risk Assessments and Emergent Work Control”; IP 71111.15, “Operability Determinations and Functionality Assessments”; and IP 71111.18, “Plant Modifications.”

# 71111.01-04	REFERENCES

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

IMC 0308, Attachment 2, “Technical Basis for Inspection Program”

IP 71111.07, “Heat Exchanger/Sink Performance”

IP 71111.12, “Maintenance Effectiveness”

IP 71111.13, “Maintenance Risk Assessments and Emergent Work Control”

IP 71111.15, “Operability Determinations and Functionality Assessments”

IP 71111.18, “Plant Modifications”

IP 71152, “Problem Identification and Resolution”

# END

Issue Date: 08/01/22	1	71111.01

Attachment 1: Revision History for IP 71111.01

Issue Date: 08/01/22	Att1-2	71111.01